ANNEXES

Annex Number	Annex title	Page
I	Requirements for any other specified fuels, fuel mixtures or fuel emulsions
II	Arrangements with regard to conformity of production
III	Methodology for adapting the emission laboratory test results to include the deterioration factors
IV	Requirements with regard to emission control strategies, NOx control measures and particulate control measures
V	Measurements and tests with regard to the area associated with the non-road steady-state test cycle
VI	Conditions, methods, procedures and apparatus for the conduct of tests and for emission measurement and sampling
VII	Method for data evaluation and calculations
VIII	Performance requirements and test procedures for dual-fuel engines
IX	Technical characteristics of the reference fuels
X	Detailed technical specifications and conditions for delivering an engine separately from its exhaust after-treatment system
XI	Detailed technical specifications and conditions for the temporary placing on the market for the purposes of field testing
XII	Detailed technical specifications and conditions for special purpose engines
XIII	Acceptance of equivalent engine type-approvals
XIV	Details of the relevant information and instructions for OEMs
XV	Details of the relevant information and instructions for end-users
XVI	Performance standards and assessment of technical services
XVII	Characteristics of the steady-state and transient test cycles

ANNEX I

Requirements for any other specified fuels, fuel mixtures or fuel emulsions

1.   Requirements for engines fuelled with liquid fuels

1.1.   When applying for an EU type-approval, manufacturers may select one of the following options with regard to the engine's fuel range:

(a)	standard fuel range engine, in accordance with the requirements set out in point 1.2; or,

(b)	fuel-specific engine, in accordance with the requirements set out in point 1.3.

1.2.   Requirements for a standard fuel range (diesel, petrol) engine

A standard fuel range engine shall meet the requirements specified in points 1.2.1 to 1.2.4.

1.2.1.   The parent engine shall meet the applicable limit values set out in Annex II to Regulation (EU) 2016/1628 and the requirements set out in this Regulation when the engine is operated on the reference fuels specified in sections 1.1 or 2.1 of Annex IX.

1.2.2.   In the absence of either a standard from the European Committee for Standardization (‘CEN standard’) for non-road gas-oil or a table of fuel properties for non-road gas-oil in Directive 98/70/EC of the European Parliament and of the Council (1), the diesel (non-road gas-oil) reference fuel in Annex IX shall represent market non-road gas-oils with a sulphur content not greater than 10 mg/kg, cetane number not less than 45 and an Fatty-Acid Methyl Ester (‘FAME’) content not greater than 7,0 % v/v. Except where otherwise permitted in accordance with points 1.2.2.1, 1.2.3 and 1.2.4, the manufacturer shall make a corresponding declaration to the end-users in accordance with the requirements in Annex XV that operation of the engine on non-road gas-oil is limited to those fuels with a sulphur content not greater than 10 mg/kg (20 mg/kg at point of final distribution) cetane number not less than 45 and an FAME content not greater than 7,0 % v/v. The manufacturer may optionally specify other parameters (e.g. for lubricity).

1.2.2.1.   The engine manufacturer shall not indicate at the moment of EU type-approval that an engine type or engine family may be operated within the Union on market fuels other than those that comply with the requirements in this point unless the manufacturer additionally complies with the requirement in point 1.2.3.

(a)	In the case of petrol, Directive 98/70/EC or the CEN standard EN 228:2012. Lubricating oil may be added according to the specification of the manufacturer;

(b)	In the case of diesel (other than non-road gas-oil), Directive 98/70/EC of the European Parliament and of the Council or the CEN standard EN 590:2013;

(c)	In the case of diesel (non-road gas-oil), Directive 98/70/EC and also both a cetane number not less than 45 and FAME not greater than 7,0 % v/v.

1.2.3.   If the manufacturer permits engines to run on additional market fuels other than those identified in point 1.2.2, such as running on B100 (EN 14214:2012+A1:2014), B20 or B30 (EN16709:2015), or on specific fuels, fuel mixtures or fuel emulsions, all of the following actions shall be taken by the manufacturer in addition to the requirements of point 1.2.2.1:

(a)	declare, in the information document set out in Commission Implementing Regulation (EU) 2017/656 (2), the specification of the commercial fuels, fuel mixtures or emulsions on which the engine family is capable to run;

(b)	demonstrate the capability of the parent engine to meet the requirements of this Regulation on the fuels, fuel mixtures or emulsions declared;

(c)

be liable to meet the requirements of in-service monitoring specified in Commission Delegated Regulation (EU) 2017/655 (3) on the fuels, fuel mixtures or emulsions declared, including any blend between the declared fuels, fuel mixtures or emulsions, and the applicable market fuel identified in point 1.2.2.1.

1.2.4.   For SI engines, the fuel/oil mixture ratio must be the ratio which shall be recommended by the manufacturer. The percentage of oil in the fuel/lubricant mixture shall be recorded in the information document set out in Implementing Regulation (EU) 2017/656.

1.3.   Requirements for a fuel-specific (ED 95 or E 85) engine

A specific fuel (ED 95 or E 85) engine shall meet the requirements specified in points 1.3.1 and 1.3.2.

1.3.1.   For ED 95, the parent engine shall meet the applicable limit values set out in Annex II to Regulation (EU) 2016/1628 and the requirements set out in this Regulation when the engine is operated on the reference fuel specified in point 1.2 of Annex IX.

1.3.2.   For E 85, the parent engine shall meet the applicable limit values set out in Annex II to Regulation (EU) 2016/1628 and the requirements set out in this Regulation when the engine is operated on the reference fuel specified point 2.2 of Annex IX.

2.   Requirements for engines fuelled with natural gas/biomethane (NG) or liquefied petroleum gas (LPG), including dual-fuel engines

2.1.   When applying for an EU type-approval, manufacturers may select one of the following options with regard to the engine's fuel range:

(a)	universal fuel range engine, in accordance with the requirements set out in point 2.3;

(b)	restricted fuel range engine, in accordance with the requirements set out in point 2.4;

(c)	fuel-specific engine, in accordance with the requirements set out in point 2.5.

2.2.   Tables summarizing the requirements for EU type-approval of natural gas/biomethane fuelled engines, LPG-fuelled engines and dual-fuel engines are provided in Appendix 1.

2.3.   Requirements for a universal fuel range engine

2.3.1.   For engines fuelled with natural gas/biomethane, including dual-fuel engines, the manufacturer shall demonstrate the parent engine's capability to adapt to any natural gas/biomethane composition that may occur across the market. That demonstration shall be carried out in accordance with this section 2 and in case of dual-fuel engines, also in accordance with the additional provisions regarding the fuel adaptation procedure set out in point 6.4 of Annex VIII.

2.3.1.1.   For engines fuelled with compressed natural gas/biomethane (CNG) there are generally two types of fuel, high calorific fuel (H-gas) and low calorific fuel (L-gas), but with a significant spread within both ranges; they differ significantly in their energy content expressed by the Wobbe Index and in their λ-shift factor (Sλ). Natural gases with a λ-shift factor between 0,89 and 1,08 (0,89 ≤ Sλ ≤ 1,08) are considered to belong to H-range, while natural gases with a λ-shift factor between 1,08 and 1,19 (1,08 ≤ Sλ ≤ 1,19) are considered to belong to L-range. The composition of the reference fuels reflects the extreme variations of Sλ.

The parent engine shall meet the requirements of this Regulation on the reference fuels GR (fuel 1) and G25 (fuel 2), as specified in Annex IX, or on the equivalent fuels created using admixtures of pipeline gas with other gases as specified in Appendix 1 of Annex IX, without any manual readjustment to the engine fuelling system between the two tests (self-adaptation is required). One adaptation run is permitted after the change of the fuel. The adaption run shall consist of performing the pre-conditioning for the following emission test according to the respective test cycle. In the case of engines tested on the non-road steady-state test cycles (‘NRSC’), where the pre-conditioning cycle is inadequate for the engine fuelling to self-adapt an alternative adaption run specified by the manufacturer may be performed prior to pre-conditioning the engine.

2.3.1.1.1.   The manufacturer may test the engine on a third fuel (fuel 3) if the λ-shift factor (Sλ) lies between 0,89 (that is the lower range of GR) and 1,19 (that is the upper range of G25), for example when fuel 3 is a market fuel. The results of this test may be used as a basis for the evaluation of the conformity of the production.

2.3.1.2.   For engines fuelled with liquefied natural gas/liquefied biomethane (LNG), the parent engine shall meet the requirements of this Regulation on the reference fuels GR (fuel 1) and G20 (fuel 2), as specified in Annex IX, or on the equivalent fuels created using admixtures of pipeline gas with other gases as specified in Appendix 1 of Annex IX, without any manual readjustment to the engine fuelling system between the two tests (self-adaptation is required). One adaptation run is permitted after the change of the fuel. The adaption run shall consist of performing the pre-conditioning for the following emission test according to the respective test cycle. In the case of engines tested on the NRSC, where the pre-conditioning cycle is inadequate for the engine fuelling to self-adapt an alternative adaption run specified by the manufacturer may be performed prior to pre-conditioning the engine.

2.3.2.   For engines fuelled with compressed natural gas/biomethane (CNG) which are self-adaptive for the range of H-gases on the one hand and the range of L-gases on the other hand, and which switch between the H-range and the L-range by means of a switch, the parent engine shall be tested on the relevant reference fuel as specified in in Annex IX for each range, at each position of the switch. The fuels are GR (fuel 1) and G23 (fuel 3) for the H-range of gases and G25 (fuel 2) and G23 (fuel 3) for the L-range of gases, or the equivalent fuels created using admixtures of pipeline gas with other gases as specified in Appendix 1 of Annex IX. The parent engine shall meet the requirements of this Regulation at both positions of the switch without any readjustment to the fuelling between the two tests at each position of the switch. One adaptation run is permitted after the change of the fuel. The adaption run shall consist of performing the pre-conditioning for the following emission test according to the respective test cycle. In the case of engines tested on the NRSC, where the pre-conditioning cycle is inadequate for the engine fuelling to self-adapt an alternative adaption run specified by the manufacturer may be performed prior to pre-conditioning the engine.

2.3.2.1.   The manufacturers may test the engine on a third fuel instead of G23 (fuel 3) if the λ-shift factor (Sλ) lies between 0,89 (that is the lower range of GR) and 1,19 (that is the upper range of G25), for example when fuel 3 is a market fuel. The results of this test may be used as a basis for the evaluation of the conformity of the production.

2.3.3.   For engines fuelled with natural gas/biomethane, the ratio of the emission results ‘r’ shall be determined for each pollutant as follows:

or,

and

2.3.4.   For engines fuelled with LPG the manufacturer shall demonstrate the parent engine's capability to adapt to any fuel composition that may occur across the market.

For engines fuelled with LPG there are variations in C3/C4 composition. These variations are reflected in the reference fuels. The parent engine shall meet the emission requirements on the reference fuels A and B as specified in Annex IX without any readjustment to the fuelling between the two tests. One adaptation run is permitted after the change of the fuel. The adaption run shall consist of performing the pre-conditioning for the following emission test according to the respective test cycle. In the case of engines tested on the NRSC, where the pre-conditioning cycle is inadequate for the engine fuelling to self-adapt an alternative adaption run specified by the manufacturer may be performed prior to pre-conditioning the engine.

2.3.4.1.   The ratio of emission results ‘r’ shall be determined for each pollutant as follows:

2.4.   Requirements for a restricted fuel range engine

A restricted fuel range engine shall meet the requirements specified in points 2.4.1 to 2.4.3.

2.4.1.   For engines fuelled with CNG and designed for operation on either the range of H-gases or on the range of L-gases

2.4.1.1.   The parent engine shall be tested on the relevant reference fuel, as specified in Annex IX, for the relevant range. The fuels are GR (fuel 1) and G23 (fuel 3) for the H-range of gases and G25 (fuel 2) and G23 (fuel 3) for the L-range of gases or the equivalent fuels created using admixtures of pipeline gas with other gases as specified in Appendix 1 of Annex IX. The parent engine shall meet the requirements of this Regulation without any readjustment to the fuelling between the two tests. One adaptation run is permitted after the change of the fuel. The adaption run shall consist of performing the pre-conditioning for the following emission test according to the respective test cycle. In the case of engines tested on the NRSC, where the pre-conditioning cycle is inadequate for the engine fuelling to self-adapt an alternative adaption run specified by the manufacturer may be performed prior to pre-conditioning the engine.

2.4.1.2.   The manufacturers may test the engine on a third fuel instead of G23 (fuel 3) if the λ-shift factor (Sλ) lies between 0,89 (that is the lower range of GR) and 1,19 (that is the upper range of G25), for example when fuel 3 is a market fuel. The results of this test may be used as a basis for the evaluation of the conformity of the production.

2.4.1.3.   The ratio of emission results ‘r’ shall be determined for each pollutant as follows:

or,

and

2.4.1.4.   On delivery to the customer the engine shall bear a label as specified in Annex III to Regulation (EU) 2016/1628 stating for which range of gases the engine is EU type-approved.

2.4.2.   For engines fuelled with natural gas or LPG and designed for operation on one specific fuel composition

2.4.2.1.   The parent engine shall meet the emission requirements on the reference fuels GR and G25 or on the equivalent fuels created using admixtures of pipeline gas with other gases as specified in Appendix 1 of Annex IX in the case of CNG, on the reference fuels GR and G20 or on the equivalent fuels created using admixtures of pipeline gas with other gases as specified in Appendix 2 of Annex VI in the case of LNG, or on the reference fuels A and B in the case of LPG, as specified in Annex IX. Fine-tuning of the fuelling system is allowed between the tests. This fine-tuning will consist of a recalibration of the fuelling database, without any alteration to either the basic control strategy or the basic structure of the database. If necessary the exchange of parts that are directly related to the amount of fuel flow such as injector nozzles is allowed.

2.4.2.2.   For engines fuelled with CNG, the manufacturer may test the engine on the reference fuels GR and G23, or on the reference fuels G25 and G23, or on the equivalent fuels created using admixtures of pipeline gas with other gases as specified in Appendix 1 of Annex IX, in which case the EU type-approval is only valid for the H-range or the L-range of gases respectively.

2.4.2.3.   On delivery to the customer the engine shall bear a label as specified in Annex III to Implementing Regulation (EU) 2017/656 stating for which fuel range composition the engine has been calibrated.

2.5.   Requirements for a fuel-specific engine fuelled with liquefied natural gas/liquefied biomethane (LNG)

A fuel-specific engine fuelled with liquefied natural gas/liquefied biomethane shall meet the requirements specified in points 2.5.1 to 2.5.2.

2.5.1.   Fuel-specific engine fuelled with liquefied natural gas/liquefied biomethane (LNG)

2.5.1.1.   The engine shall be calibrated for a specific LNG gas composition resulting in a λ-shift factor not differing by more than 3 % from the λ -shift factor of the G20 fuel specified in Annex IX, and the ethane content of which does not exceed 1,5 %.

2.5.1.2.   If the requirements set out in point 2.5.1.1.are not fulfilled, the manufacturer shall apply for a universal fuel engine according to the specifications set out in point 2.1.3.2.

2.5.2.   Fuel-specific engine fuelled with Liquefied Natural Gas (LNG)

2.5.2.1.   For a dual-fuel engine family the engines shall be calibrated for a specific LNG gas composition resulting in a λ-shift factor not differing by more than 3 % from the λ-shift factor of the G20 fuel specified in Annex IX, and the ethane content of which does not exceed 1,5 %, the parent engine shall only be tested on the G20 reference gas fuel, or on the equivalent fuel created using an admixture of pipeline gas with other gases, as specified in Appendix 1 of Annex IX.

2.6.   EU type-approval of a member of a family

2.6.1.   With the exception of the case mentioned in point 2.6.2, the EU type-approval of a parent engine shall be extended to all family members, without further testing, for any fuel composition within the range for which the parent engine has been EU type-approved (in the case of engines described in point 2.5) or the same range of fuels (in the case of engines described in either point 2.3 or 2.4) for which the parent engine has been EU type-approved.

2.6.2.   Where the technical service determines that, with regard to the selected parent engine the submitted application does not fully represent the engine family defined in Annex IX to Implementing Regulation (EU) 2017/656, an alternative and if necessary an additional reference test engine may be selected by the technical service and tested.

2.7.   Additional requirements for dual-fuel engines

In order to receive an EU type-approval of a dual-fuel engine type or engine family, the manufacturer shall:

(a)	conduct the tests in accordance with Table 1.3 of Appendix 1;

(b)	in addition to the requirements set out in section 2, demonstrate that the dual-fuel engines are subject to the tests and comply with the requirements set out in Annex VIII.

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(1)  Directive 98/70/EC of the European Parliament and of the Council of 13 October 1998 relating to the quality of petrol and diesel fuels and amending Council Directive 93/12/EEC (OJ L 350, 28.12.1998, p. 58).

(2)  Commission Implementing Regulation (EU) 2017/656 of 19 December 2016 laying down the administrative requirements relating to emission limits and type-approval of internal combustion engines for non-road mobile machinery in accordance with Regulation (EU) 2016/1628 of the European Parliament and of the Council (See page 364 of this Official Journal).

(3)  Commission Delegated Regulation (EU) 2017/655 of 19 December 2016 supplementing Regulation (EU) 2016/1628 of the European Parliament and of the Council with regard to monitoring of gaseous pollutant emissions from in-service internal combustion engines installed in non-road mobile machinery (See page 334 of this Official Journal).

ANNEX II

Arrangements with regard to conformity of production

1.   Definitions

For the purposes of this Annex the following definitions shall apply:

1.1.	‘quality management system’ means a set of interrelated or interacting elements that organisations use to direct and control how quality policies are implemented and quality objectives are achieved;

1.2.	‘audit’ means an evidence-gathering process used to evaluate how well audit criteria are being applied; it should be objective, impartial and independent, and the audit process should be both systematic and documented;

1.3.	‘corrective actions’ means a problem-solving process with subsequent steps taken to remove the causes of a nonconformity or undesirable situation and designed to prevent their recurrence;

2.   Purpose

2.1.   The conformity of production arrangements aim to ensure that each engine is in conformity with the specification, performance and marking requirements of the approved engine type or engine family.

2.2.   Procedures include, inseparably, the assessment of quality management systems, referred as ‘initial assessment’ and set out in section 3 and verification and production-related controls, referred to as ‘product conformity arrangements’ and set out in section 4.

3.   Initial assessment

3.1.   Before granting EU type-approval, the approval authority shall verify the existence of satisfactory arrangements and procedures established by the manufacturer for ensuring effective control so that engines when in production conform to the approved engine type or engine family.

3.2.   Guidelines for quality and/or environmental management systems auditing set out in the EN ISO 19011:2011 standard shall apply to the initial assessment.

3.3.   The approval authority shall be satisfied with the initial assessment and the product conformity arrangements in section 4 taking account as necessary of one of the arrangements described in points 3.3.1 to 3.3.3 or a combination of those arrangements in full or in part as appropriate.

3.3.1.   The initial assessment and/or verification of product conformity arrangements shall be carried out by the approval authority granting the approval or an appointed body acting on behalf of the approval authority.

3.3.1.1.   When considering the extent of the initial assessment to be carried out, the approval authority may take account of available information relating to the manufacturer's certification which has not been accepted under point 3.3.3.

3.3.2.   The initial assessment and verification of product conformity arrangements may also be carried out by the approval authority of another Member State, or the appointed body designated for this purpose by the approval authority.

3.3.2.1.   In such a case, the approval authority of the other Member State shall prepare a statement of compliance outlining the areas and production facilities it has covered as relevant to the engines to be EU type-approved.

3.3.2.2.   On receiving an application for a compliance statement from the approval authority of a Member State granting EU type-approval, the approval authority of another Member State shall send forthwith the statement of compliance or advise that it is not in a position to provide such a statement.

3.3.2.3.   The statement of compliance shall include at least the following:

3.3.2.3.1.

group or company (e.g. XYZ manufacturing);

3.3.2.3.2.

particular organisation (e.g. European division);

3.3.2.3.3.

plants/sites (e.g. engine plant 1 (United Kingdom) — engine plant 2 (Germany));

3.3.2.3.4.

engine types/engine families included

3.3.2.3.5.

areas assessed (e.g. engine assembly, engine testing, after-treatment manufacture)

3.3.2.3.6.

documents examined (e.g. company and site quality manual and procedures);

3.3.2.3.7.

date of the assessment (e.g. audit conducted from 18 to 30.5.2013);

3.3.2.3.8.

planned monitoring visit (e.g. October 2014).

3.3.3.   The approval authority shall also accept the manufacturer's suitable certification to harmonised standard EN ISO 9001:2008 or an equivalent harmonised standard as satisfying the initial assessment requirements of point 3.3. The manufacturer shall provide details of the certification and undertake to inform the approval authority of any revisions to its validity or scope.

4.   Product conformity arrangements

4.1.   Every engine EU type-approved pursuant to Regulation (EU) 2016/1628, this Delegated Regulation, Delegated Regulation (EU) 2017/655 and Implementing Regulation (EU) 2017/656 shall be so manufactured as to conform to the approved engine type or engine family by meeting the requirements of this Annex, Regulation (EU) 2016/1628 and the abovementioned Delegated and Implementing Regulations.

4.2.   Before granting a EU type-approval pursuant to Regulation (EU) 2016/1628 and the delegated and implementing acts adopted pursuant to that Regulation, the approval authority shall verify the existence of adequate arrangements and documented control plans, to be agreed with the manufacturer for each approval, to carry out at specified intervals those tests or associated checks necessary to verify continued conformity with the approved engine type or engine family, including, where applicable, tests specified in Regulation (EU) 2016/1628 and the delegated and implementing acts adopted pursuant to that Regulation.

4.3.   The holder of the EU type-approval shall:

4.3.1.

ensure the existence and application of procedures for effective control of the conformity of engines to the approved engine type or engine family;

4.3.2.

have access to the testing or other appropriate equipment necessary for checking conformity to each approved engine type or engine family;

4.3.3.

ensure that test or check result data are recorded and that annexed documents remain available for a period of up to 10 years to be determined in agreement with the approval authority;

4.3.4.

for engine categories NRSh and NRS, except for NRS-v-2b and NRS-v-3, ensure that for each type of engine, at least the checks and the tests prescribed in Regulation (EU) 2016/1628 and the delegated and implementing acts adopted pursuant to that Regulation are carried out. For other categories tests at a component or assembly of components level with appropriate criterion may be agreed between the manufacturer and the approval authority.

4.3.5.

analyse the results of each type of test or check, in order to verify and ensure the stability of the product characteristics, making allowance for variation in industrial production;

4.3.6.

ensure that any set of samples or test pieces giving evidence of non-conformity in the type of test in question gives rise to a further sampling and test or check.

4.4.   If the further audit or check results referred to in point 4.3.6 are deemed not to be satisfactory in the opinion of the approval authority, the manufacturer shall ensure that conformity of production is restored as soon as possible by corrective actions to the satisfaction of the approval authority.

5.   Continued verification arrangements

5.1.   The authority which has granted EU type-approval may at any time verify the conformity of production control methods applied in each production facility by means of periodic audits. The manufacturer shall for that purpose allow access to the manufacture, inspection, testing, storage and distribution sites and shall provide all necessary information with regard to the quality management system documentation and records.

5.1.1.   The normal approach for such periodic audits shall be to monitor the continued effectiveness of the procedures laid down in sections 3 and 4 (initial assessment and product conformity arrangements).

5.1.1.1.   Surveillance activities carried out by the technical services (qualified or recognised as required in point 3.3.3) shall be accepted as satisfying the requirements of point 5.1.1 with regard to the procedures established at initial assessment.

5.1.1.2.   The minimum frequency of verifications (other than those referred to in point 5.1.1.1) to ensure that the relevant conformity of production controls applied in accordance with sections 3 and 4 are reviewed over a period consistent with the climate of trust established by the approval authority shall be at least once every two years. However, additional verifications shall be carried out by the approval authority depending on the yearly production, the results of previous evaluations, the need to monitor corrective actions and upon a reasoned request from another approval authority or any market surveillance authority.

5.2.   At every review, the records of tests, checks and production records, and in particular the records of those tests or checks documented as required in point 4.2, shall be available to the inspector.

5.3.   The inspector may select random samples to be tested in the manufacturer's laboratory or in the facilities of the technical service, in which case only physical tests shall be carried out. The minimum number of samples may be determined according to the results of the manufacturer's own verification.

5.4.   Where the level of control appears unsatisfactory, or when it seems necessary to verify the validity of the tests carried out in application of point 5.2, or upon a reasoned request from another approval authority or any market surveillance authority, the inspector shall select samples to be tested in the manufacturer's laboratory or sent to the technical service to perform physical tests in accordance with the requirements set out in section 6, in Regulation (EU) 2016/1628 and in the delegated and implementing acts adopted pursuant to that Regulation.

5.5.   Where unsatisfactory results are found by the approval authority during an inspection or a monitoring review, or by an approval authority in other Member State, in accordance with Article 39(3) of Regulation (EU) 2016/1628, the approval authority shall ensure that all necessary steps are taken to restore conformity of production as rapidly as possible.

6.   Conformity of production test requirements in cases of an unsatisfactory level of product conformity control as referred to in point 5.4.

6.1.   In case of an unsatisfactory level of product conformity control as referred to in point 5.4 or point 5.5, conformity of production shall be checked by emissions testing on the basis of the description in the EU type-approval certificates set out in Annex IV to Implementing Regulation (EU) 2017/656.

6.2.   Except otherwise provided in point 6.3, the following procedure shall apply:

6.2.1.   Three engines and, if applicable, three after-treatment systems shall randomly be taken for inspection from the series production of the engine type under consideration. Additional engines shall be taken as necessary to reach a pass or fail decision. For reaching a pass decision, a minimum of four engines needs to be tested.

6.2.2.   After the inspector's selection of the engines, the manufacturer shall not carry out any adjustment to the engines selected.

6.2.3.   Engines shall be subjected to emissions testing in accordance with the requirements of Annex VI, or, in the case of dual fuel engines, in accordance with Appendix 2 of Annex VIII, and shall be subject to the test cycles relevant for the engine type in accordance with Annex XVII.

6.2.4.   The limit values shall be those set out in Annex II to Regulation (EU) 2016/1628. Where an engine with after-treatment regenerates infrequently as referred to in point 6.6.2 of Annex VI, each gaseous or particulate pollutant emission result shall be adjusted by the factor applicable to the engine type. In all cases each gaseous or particulate pollutant emission result shall be adjusted by application of the appropriate deterioration factors (DFs) for that engine type, as determined in accordance with Annex III.

6.2.5.   The tests shall be carried out on newly manufactured engines.

6.2.5.1.   At the request of the manufacturer, the tests may be conducted on engines which have been run-in, up either 2 % of the emission durability period or, if this is a shorter period of time, 125 hours. Where the run-in procedure shall be conducted by the manufacturer who shall undertake not to make any adjustments to those engines. Where the manufacturer has specified a run-in procedure in point 3.3 of the information document, as set out in Annex I to Implementing Regulation (EU) 2017/656, the run-in shall be conducted using that procedure.

6.2.6.   On the basis of tests of the engine by sampling as set out in Appendix 1, the series production of the engines under consideration is regarded as conforming to the approved type where a pass decision is reached for all the pollutants and as non-conforming to the approved type where a fail decision is reached for one pollutant, in accordance with the test criteria applied in Appendix 1, and as shown in Figure 2.1.

6.2.7.   When a pass decision has been reached for one pollutant, this decision may not be changed as a consequence of a result from any additional tests made in order to reach a decision for the other pollutants.

If a pass decision is not reached for all the pollutants and no fail decision is reached for any of the pollutant, a test shall be carried out on another engine.

6.2.8.   If no decision is reached, the manufacturer may at any time decide to stop testing. In that case a fail decision shall be recorded.

6.3.   By derogation from point 6.2.1, the following procedure shall apply for engine types with a sales volume within the EU of less than 100 units per year:

6.3.1.

One engine and, if applicable, one after-treatment system shall be taken randomly for inspection from the series production of the engine type under consideration.

6.3.2.

If the engine meets the requirements outlined in point 6.2.4, a pass decision is reached and no further test is necessary.

6.3.3.

If the test does not satisfy the requirements outlined in point 6.2.4, the procedure outlined in points 6.2.6 to 6.2.9 shall be followed.

6.4.   All these tests may be conducted with the applicable market fuels. However, at the manufacturer's request, the reference fuels described in Annex IX shall be used. This implies tests, as described in Appendix 1 of Annex I, with at least two of the reference fuels for each gaseous-fuelled engine, except in the case of a gaseous-fuelled engine with a fuel-specific EU type-approval where only one reference fuel is required. Where more than one gaseous reference fuel is used the results shall demonstrate that the engine meets the limit values with each fuel.

6.5.   Non-compliance of gaseous-fuelled engines

In the case of dispute concerning compliance of gaseous-fuelled engines, including dual-fuel engines, when using a market fuel, the tests shall be performed with each reference fuel on which the parent engine has been tested, and, at the request of the manufacturer, with the possible additional third fuel, as referred to in points 2.3.1.1.1, 2.3.2.1 and 2.4.1.2 of Annex I, on which the parent engine may have been tested. When applicable, the result shall be converted by a calculation, applying the relevant factors ‘r’, ‘r a’ or ‘r b’ as described in points 2.3.3, 2.3.4.1 and 2.4.1.3 of Annex I. If r, r a or r b are less than 1, no correction shall take place. The measured results and, when applicable, the calculated results shall demonstrate that the engine meets the limit values with all relevant fuels (for example fuels 1, 2 and, if applicable, the third fuel in the case of natural gas/bio-methane engines, and fuels A and B in the case of LPG engines).

Figure 2.1

Schematic of production conformity testing

ANNEX III

Methodology for adapting the emission laboratory test results to include the deterioration factors

1.   Definitions

For the purposes of this Annex, the following definitions apply:

1.1.	‘Ageing cycle’ means the non-road mobile machinery or engine operation (speed, load, power) to be executed during the service accumulation period.

1.2.	‘Critical emission-related components’ means the exhaust after- treatment system, the electronic engine control unit and its associated sensors and actuators, and the exhaust gas recirculation (EGR) including all related filters, coolers, control valves and tubing.

1.3.	‘Critical emission-related maintenance’ means the maintenance to be performed on critical emission-related components of the engine.

1.4.	‘Emission-related maintenance’ means the maintenance which substantially affects emissions or which is likely to affect emissions performance of the non-road mobile machinery or the engine during normal in-use operation.

1.5.	‘Engine-after-treatment system family’ means a manufacturer's grouping of engines that comply with the definition of engine family, but which are further grouped into a family of engine families utilising a similar exhaust after-treatment system.

1.6.	‘Non-emission-related maintenance’ means maintenance which does not substantially affect emissions and which does not have a lasting effect on the emissions performance deterioration of the non-road mobile machinery or the engine during normal in-use operation once the maintenance is performed.

1.7.	‘Service accumulation schedule’ means the ageing cycle and the service accumulation period for determining the deterioration factors for the engine-after-treatment system family.

2.   General

2.1.   This Annex details the procedures for selecting engines to be tested over a service accumulation schedule for the purpose of determining deterioration factors for engine type or engine family EU type-approval and conformity of production assessments. The deterioration factors shall be applied to the emissions measured in accordance with Annex VI and calculated in accordance with Annex VII in accordance with the procedure set out in point 3.2.7 or point 4.3, respectively.

2.2.   The service accumulation tests or the emissions tests performed to determine deterioration need not be witnessed by the approval authority.

2.3.   This Annex also details the emission-related and non-emission-related maintenance that should be or may be carried out on engines undergoing a service accumulation schedule. Such maintenance shall conform to the maintenance performed on in-service engines and communicated to the end-users of new engines.

3.   Engine categories NRE, NRG, IWP, IWA, RLL, RLR, SMB, ATS and sub-categories NRS-v-2b and NRS-v-3

3.1.   Selection of engines for establishing emission durability period deterioration factors

3.1.1.   Engines shall be selected from the engine family defined in section 2 of Annex IX to Implementing Regulation (EU) 2017/656 for emission testing to establish emission durability period deterioration factors.

3.1.2.   Engines from different engine families may be further combined into families based on the type of exhaust after-treatment system utilised. In order to place engines with a different cylinder configuration but having similar technical specifications and installation for the exhaust after-treatment systems into the same engine after-treatment system family, the manufacturer shall provide data to the approval authority that demonstrates that the emissions reduction performance of such engines is similar.

3.1.3.   The engine manufacturer shall select one engine representing the engine-after-treatment system family, as determined in accordance with point 3.1.2, for testing over the service accumulation schedule referred to in point 3.2.2, and shall be reported to the approval authority before any testing commences.

3.1.4.   If the approval authority decides that the worst case emissions of the engine-after-treatment system family can be better characterised by another test engine, the test engine to be used shall be selected jointly by the approval authority and the engine manufacturer.

3.2.   Determination of emission durability period deterioration factors

3.2.1.   General

Deterioration factors applicable to an engine-after-treatment system family shall be developed from the selected engines based on a service accumulation schedule that includes periodic testing for gaseous and particulate emissions over each test cycle applicable to the engine category, as given in Annex IV to Regulation (EU) 2016/1628. In the case of non-road transient test cycles for engines of category NRE (‘NRTC’), only the results of the hot-start run of the NRTC (‘hot-start NRTC’) shall be used.

3.2.1.1.   At the request of the manufacturer, the approval authority may allow the use of deterioration factors that have been established using alternative procedures to those specified in points 3.2.2 to 3.2.5. In that case, the manufacturer shall demonstrate to the satisfaction of the approval authority that the alternative procedures used are not less rigorous than those set out in points 3.2.2 to 3.2.5.

3.2.2.   Service accumulation schedule

Service accumulation schedules may be carried out at the choice of the manufacturer by running a non-road mobile machinery equipped with the selected engine over an ‘in-service’ accumulation schedule or by running the selected engine over a ‘dynamometer service’ accumulation schedule. The manufacturer shall not be required to use reference fuel for the service accumulation in-between emission measurement test points.

3.2.2.1.   In-service and dynamometer service accumulation

3.2.2.1.1.   The manufacturer shall determine the form and duration of the service accumulation and the ageing cycle for engines in a manner consistent with good engineering judgment.

3.2.2.1.2.   The manufacturer shall determine the test points where gaseous and particulate emissions will be measured over the applicable cycles, as follows:

3.2.2.1.2.1.

When running a service accumulation schedule shorter than the emission durability period in accordance with point 3.2.2.1.7, the minimum number of test points shall be three, one at the beginning, one approximately in the middle and one at the end of the service accumulation schedule.

3.2.2.1.2.2.

When completing the service accumulation up to the end of the emission durability period, the minimum number of test points shall be two, one at the beginning and one at the end of the service accumulation.

3.2.2.1.2.3.

The manufacturer may additionally test at evenly spaced intermediate points.

3.2.2.1.3.   The emission values at the start point and at the emission durability period endpoint either calculated in accordance with point 3.2.5.1 or measured directly in accordance with point 3.2.2.1.2.2, shall be within the limit values applicable to the engine family. However individual emission results from the intermediate test points may exceed those limit values.

3.2.2.1.4.   For engine categories or sub-categories to which a NRTC applies, or for engines category or sub-categories NRS to which a large spark-ignition engines non-road transient test cycles (‘LSI-NRTC’) applies, the manufacturer may request the agreement of the approval authority to run only one test cycle (either the hot-start NRTC or LSI-NRTC, as applicable, or NRSC) at each test point, and to run the other test cycle only at the beginning and at the end of the service accumulation schedule.

3.2.2.1.5.   In the case of engine categories or sub-categories for which there is no applicable non-road transient cycle given in Annex IV to Regulation (EU) 2016/1628, only the NRSC shall be run at each test point.

3.2.2.1.6.   Service accumulation schedules may be different for different engine-after-treatment system families.

3.2.2.1.7.   Service accumulation schedules may be shorter than the emission durability period, but shall not be shorter than the equivalent of at least one quarter of the relevant emission durability period specified in Annex V to Regulation (EU) 2016/1628.

3.2.2.1.8.   Accelerated ageing by adjusting the service accumulation schedule on a fuel consumption basis is permitted. The adjustment shall be based on the ratio between the typical in-use fuel consumption and the fuel consumption on the ageing cycle, but fuel consumption on the ageing cycle shall not exceed typical in-use fuel consumption by more than 30 %.

3.2.2.1.9.   The manufacturer may use, if agreed by the approval authority, alternative methods of accelerated ageing.

3.2.2.1.10.   The service accumulation schedule shall be fully described in the application for EU type-approval and reported to the approval authority before the start of any testing.

3.2.2.2.   If the approval authority decides that additional measurements need to be performed between the points selected by the manufacturer it shall notify the manufacturer. The revised service accumulation schedule shall be prepared by the manufacturer and agreed by the approval authority.

3.2.3.   Engine testing

3.2.3.1.   Engine stabilisation

3.2.3.1.1.   For each engine-after-treatment system family, the manufacturer shall determine the number of hours of non-road mobile machinery or engine running after which the operation of the engine-after-treatment system has stabilised. If requested by the approval authority the manufacturer shall make available the data and analysis used to make this determination. As an alternative, the manufacturer may run the engine or non-road mobile machinery between 60 and 125 hours or the equivalent time on the ageing cycle to stabilise the engine-after-treatment system.

3.2.3.1.2.   The end of the stabilisation period determined in point 3.2.3.1.1 shall be deemed to be the start of the service accumulation schedule.

3.2.3.2.   Service accumulation testing

3.2.3.2.1.   After stabilisation, the engine shall be run over the service accumulation schedule selected by the manufacturer, as described in point 3.2.2. At the periodic intervals in the service accumulation schedule determined by the manufacturer, and, where applicable, decided by the approval authority in accordance with point 3.2.2.2, the engine shall be tested for gaseous and particulate emissions over the hot-start NRTC and NRSC, or LSI-NRTC and NRSC applicable to the engine category, as set out in Annex IV to Regulation (EU) 2016/1628.

The manufacturer may select to measure the pollutant emissions before any exhaust after-treatment system separately from the pollutant emissions after any exhaust after-treatment system.

In accordance with point 3.2.2.1.4, if it has been agreed that only one test cycle (hot-start NRTC, LSI-NRTC or NRSC) be run at each test point, the other test cycle (hot-start NRTC, LSI-NRTC or NRSC) shall be run at the beginning and at the end of the service accumulation schedule.

In accordance with point 3.2.2.1.5, in the case of engine categories or sub-categories for which there is no applicable non-road transient cycle given in Annex IV to Regulation (EU) 2016/1628, only the NRSC shall be run at each test point.

3.2.3.2.2.   During the service accumulation schedule, maintenance shall be carried out on the engine in accordance with point 3.4.

3.2.3.2.3.   During the service accumulation schedule, unscheduled maintenance on the engine or non-road mobile machinery may be performed, for example if the manufacturer's normal diagnostic system has detected a problem that would have indicated to the non-road mobile machinery operator that a fault had arisen.

3.2.4.   Reporting

3.2.4.1.   The results of all emission tests (hot-start NRTC, LSI-NRTC and NRSC) conducted during the service accumulation schedule shall be made available to the approval authority. If an emission test is declared to be void, the manufacturer shall provide reasons why the test has been declared void. In such a case, another series of emission tests shall be carried out within the following 100 hours of service accumulation.

3.2.4.2.   The manufacturer shall retain records of all information concerning all the emission tests and maintenance carried out on the engine during the service accumulation schedule. This information shall be submitted to the approval authority along with the results of the emission tests conducted over the service accumulation schedule.

3.2.5.   Determination of deterioration factors

3.2.5.1.   When running a service accumulation schedule in accordance with point 3.2.2.1.2.1 or point 3.2.2.1.2.3, for each pollutant measured over the hot-start NRTC, LSI-NRTC and NRSC at each test point during the service accumulation schedule, a ‘best fit’ linear regression analysis shall be made on the basis of all test results. The results of each test for each pollutant shall be expressed to the same number of decimal places as the limit value for that pollutant, as applicable to the engine family, plus one additional decimal place.

Where in accordance with point 3.2.2.1.4 or point 3.2.2.1.5, only one test cycle (hot-start NRTC, LSI-NRTC or NRSC) has been run at each test point, the regression analysis shall be made only on the basis of the test results from the test cycle run at each test point.

The manufacturer may request the prior approval of the approval authority for a non-linear regression.

3.2.5.2.   The emission values for each pollutant at the start of the service accumulation schedule and at the emission durability period end point that is applicable for the engine under test shall be either:

(a)	determined by extrapolation of the regression equation in point 3.2.5.1, when running a service accumulation schedule in accordance with point 3.2.2.1.2.1 or point 3.2.2.1.2.3, or

(b)	measured directly, when running a service accumulation schedule in accordance with point 3.2.2.1.2.2.

Where emission values are used for engine families in the same engine-after-treatment family but with different emission durability periods, then the emission values at the emission durability period end point shall be recalculated for each emission durability period by extrapolation or interpolation of the regression equation as determined in point 3.2.5.1.

3.2.5.3.   The deterioration factor (DF) for each pollutant is defined as the ratio of the applied emission values at the emission durability period end point and at the start of the service accumulation schedule (multiplicative deterioration factor).

The manufacturer may request the prior approval of the approval authority for the application of an additive DF for each pollutant may be applied. The additive DF is defined as the difference between the calculated emission values at the emission durability period end point and at the start of the service accumulation schedule.

An example for determination of DFs by using linear regression is shown in Figure 3.1 for NOx emission.

Mixing of multiplicative and additive DFs within one set of pollutants is not permitted.

If the calculation results in a value of less than 1,00 for a multiplicative DF, or less than 0,00 for an additive DF, then the deterioration factor shall be 1,0 or 0,00, respectively.

In accordance with point 3.2.2.1.4, if it has been agreed that only one test cycle (hot-start NRTC, LSI-NRTC or NRSC) be run at each test point and the other test cycle (hot-start NRTC, LSI-NRTC or NRSC) run only at the beginning and end of the service accumulation schedule, the deterioration factor calculated for the test cycle that has been run at each test point shall be applicable also for the other test cycle.

Figure 3.1

Example of DF determination

3.2.6.   Assigned deterioration factors

3.2.6.1.   As an alternative to using a service accumulation schedule to determine DFs, engine manufacturers may select to use assigned multiplicative DFs, as given in Table 3.1.

Table 3.1

Assigned deterioration factors

Test cycle	CO	HC	NOx	PM	PN
NRTC and LSI-NRTC	1,3	1,3	1,15	1,05	1,0
NRSC	1,3	1,3	1,15	1,05	1,0

Assigned additive DFs shall not be given. The assigned multiplicative DFs shall not be transformed into additive DFs.

For PN, either an additive DF of 0,0 or a multiplicative DF of 1,0 may be used, in conjunction with the results of previous DF testing that did not establish a value for PN if both of the following conditions are fulfilled:

(a)	the previous DF test was conducted on engine technology that would have qualified for inclusion in the same engine after-treatment system family, as set out in point 3.1.2, as the engine family to which it is intended to apply the DFs; and,

(b)	the test results were used in a previous type-approval granted before the applicable EU type-approval date given in Annex III to Regulation (EU) 2016/1628.

3.2.6.2.   Where assigned DFs are used, the manufacturer shall present to the approval authority robust evidence that the emission control components can reasonably be expected to have the emission durability associated with those assigned factors. This evidence may be based upon design analysis, or tests, or a combination of both.

3.2.7.   Application of deterioration factors

3.2.7.1.   The engines shall meet the respective emission limits for each pollutant, as applicable to the engine family, after application of the deterioration factors to the test result as measured in accordance with Annex VI (cycle-weighted specific emission for particulate and each individual gas). Depending on the type of DF, the following provisions apply:

(a)	Multiplicative: (cycle weighted specific emission) × DF ≤ emission limit

(b)	Additive: (cycle weighted specific emission) + DF ≤ emission limit

Cycle weighted specific emission may include the adjustment for infrequent regeneration, where applicable.

3.2.7.2.   For a multiplicative NOx + HC DF, separate HC and NOx DFs shall be determined and applied separately when calculating the deteriorated emission levels from an emissions test result before combining the resultant deteriorated NOx and HC values to establish compliance with the emission limit.

3.2.7.3.   The manufacturer may carry across the DFs determined for an engine-after-treatment system family to an engine that does not fall into the same engine-after-treatment system family. In such cases, the manufacturer shall demonstrate to the approval authority that the engine for which the engine-after-treatment system family was originally tested and the engine for which the DFs are being carried across have similar technical specifications and installation requirements on the non-road mobile machinery and that the emissions of such engine are similar.

Where DFs are carried across to an engine with a different emission durability period, the DFs shall be recalculated for the applicable emission durability period by extrapolation or interpolation of the regression equation as determined in point 3.2.5.1.

3.2.7.4.   The DF for each pollutant for each applicable test cycle shall be recorded in the test report set out in Appendix 1 of Annex VI to Implementing Regulation (EU) 2017/656.

3.3.   Checking of conformity of production

3.3.1.   Conformity of production for emissions compliance is checked on the basis of Section 6 of Annex II.

3.3.2.   The manufacturer may measure the pollutant emissions before any exhaust after-treatment system at the same time as the EU type-approval test is being performed. For that purpose, the manufacturer may develop informal DFs separately for the engine without after-treatment system and for the after-treatment system that may be used by the manufacturer as an aid to end of production line auditing.

3.3.3.   For the purposes of EU type-approval, only the DFs determined in accordance with point 3.2.5 or 3.2.6 shall be recorded in the test report set out in Appendix 1 of Annex VI to Implementing Regulation (EU) 2017/656.

3.4.   Maintenance

For the purpose of the service accumulation schedule, maintenance shall be performed in accordance with the manufacturer's manual for service and maintenance.

3.4.1.   Scheduled emission-related maintenance

3.4.1.1.   Scheduled emission-related maintenance during engine running, undertaken for the purpose of conducting a service accumulation schedule, shall occur at equivalent intervals to those that are specified in the manufacturer's maintenance instructions to the end-user of the non-road mobile machinery or engine. This schedule maintenance may be updated as necessary throughout the service accumulation schedule provided that no maintenance operation is deleted from the maintenance schedule after the operation has been performed on the test engine.

3.4.1.2.   Any adjustment, disassembly, cleaning or exchange of critical emission-related components which is performed on a periodic basis within the emission durability period to prevent malfunction of the engine, shall only be done to the extent that is technologically necessary to ensure proper functioning of the emission control system. The need for scheduled exchange, within the service accumulation schedule and after a certain running time of the engine, of critical emission-related components other than those qualifying as routine exchange items shall be avoided. In this context, consumable maintenance items for regular renewal or items that require cleaning after a certain running time of the engine, shall qualify as routine exchange items.

3.4.1.3.   Any scheduled maintenance requirements shall be subject to approval by the approval authority before an EU type-approval is granted and shall be included in the customer's manual. The approval authority shall not refuse to approve maintenance requirements that are reasonable and technically necessary, including but not limited to those identified in point 1.6.1.4.

3.4.1.4.   The engine manufacturer shall specify for the service accumulation schedules any adjustment, cleaning, maintenance (where necessary) and scheduled exchange of the following items:

—	filters and coolers in the exhaust gas recirculation (EGR)

—	positive crankcase ventilation valve, if applicable

—	fuel injector tips (only cleaning is permitted)

—	fuel injectors

—	turbocharger

—	electronic engine control unit and its associated sensors and actuators

—	particulate after-treatment system (including related components)

—	NOx after-treatment system (including related components)

—	exhaust gas recirculation (EGR), including all related control valves and tubing

—	any other exhaust after-treatment system.

3.4.1.5.   Scheduled critical emission-related maintenance shall only be performed if it is required to be performed in-use and that requirement is communicated to the end-user of the engine or non-road mobile machinery.

3.4.2.   Changes to scheduled maintenance

The manufacturer shall submit a request to the approval authority for approval of any new scheduled maintenance that it wishes to perform during the service accumulation schedule and subsequently to recommend to end-users of non-road mobile machinery and engines. The request shall be accompanied by data supporting the need for the new scheduled maintenance and the maintenance interval.

3.4.3.   Non-emission-related scheduled maintenance

Non-emission-related scheduled maintenance which is reasonable and technically necessary (for example oil change, oil filter change, fuel filter change, air filter change, cooling system maintenance, idle speed adjustment, governor, engine bolt torque, valve lash, injector lash, adjustment of the tension of any drive-belt, etc.) may be performed on engines or non-road mobile machinery selected for the service accumulation schedule at the least frequent intervals recommended by the manufacturer to the end-user (for example not at the intervals recommended for severe service).

3.5.   Repair

3.5.1.   Repairs to the components of an engine selected for testing over a service accumulation schedule shall be performed only as a result of component failure or engine malfunction. Repair of the engine itself, the emission control system or the fuel system is not permitted except to the extent defined in point 3.5.2.

3.5.2.   If the engine, its emission control system or its fuel system fails during the service accumulation schedule, the service accumulation shall be considered void, and a new service accumulation shall be started with a new engine.

The previous paragraph shall not apply when the failed components are replaced with equivalent components that have been subject to a similar number of hours of service accumulation.

4.   Engine categories and sub-categories NRSh and NRS, except for NRS-v-2b and NRS-v-3

4.1.   The applicable EDP category and corresponding deterioration factor (DF) shall be determined in accordance with this section 4.

4.2.   An engine family shall be considered as compliant with the limit values required for an engine sub-category when the emissions test results of all engines representing the engine family, once adjusted by multiplication by the DF laid down in section 2, are lower than or equal to the limit values required for that engine sub-category. However, where one or more emission test results of one or more engines representing the engine family, once adjusted by multiplication by the DF laid down in section 2, are higher than one or more single emission limit values required for that engine sub-category, the engine family shall be considered not compliant with the limit values required for that engine sub-category.

4.3.   DFs shall be determined as follows:

4.3.1.

On at least one test engine representing the configuration chosen to be the most likely to exceed HC + NOx emission limits, and constructed to be representative of production engines, the (full) test procedure emission testing shall be conducted as described in Annex VI after the number of hours representing stabilised emissions.

4.3.2.

If more than one engine is tested, the results shall be calculated as the average of the results for all the engines tested, rounded to the same number of decimal places as in the applicable limit, expressed to one additional significant figure.

4.3.3.

Such emission testing shall be conducted again following ageing of the engine. The ageing procedure should be designed to allow the manufacturer to appropriately predict the in-use emission deterioration expected over the EDP of the engine, taking into account the type of wear and other deterioration mechanisms expected under typical consumer use which could affect emissions performance. If more than one engine is tested, the results shall be calculated as the average of the results for all the engines tested, rounded to the same number of decimal places contained in the applicable limit, expressed to one additional significant figure.

4.3.4.

The emissions at the end of the EDP (average emissions, if applicable) for each regulated pollutant shall be divided by the stabilised emissions (average emissions, if applicable) and rounded to two significant figures. The resulting number shall be the DF, unless it is less than 1,00, in which case the DF shall be 1,00.

4.3.5.

The manufacturer may schedule additional emission test points between the stabilised emission test point and the end of the EDP. If intermediate tests are scheduled, the test points shall be evenly spaced over the EDP (plus or minus two hours) and one such test point shall be at one half of full EDP (plus or minus two hours).

4.3.6.

For each pollutant HC + NOx and CO, a straight line must be fitted to the data points treating the initial test as occurring at hour zero, and using the method of least-squares. The DF is the calculated emission at the end of the durability period divided by the calculated emission at zero hours. The DF for each pollutant for the applicable test cycle shall be recorded in the test report set out in Appendix 1 of Annex VII to Implementing Regulation (EU) 2017/656.

4.3.7.

Calculated deterioration factors may cover families in addition to the one on which they were generated if the manufacturer submits a justification acceptable to the approval authority in advance of EU type-approval that the affected engine families can be reasonably expected to have similar emission deterioration characteristic based on the design and technology used. A non-exclusive list of design and technology groupings is given below: — conventional two-stroke engines without after-treatment system, — conventional two-stroke engines with a catalyst of the same active material and loading, and the same number of cells per cm2, — stratified scavenging two-stroke engines, — stratified scavenging two-stroke engines with a catalyst of the same active material and loading, and the same number of cells per cm2, — four-stroke engines with catalyst with same valve technology and identical lubrication system, — four-stroke engines without catalyst with the same valve technology and identical lubrication system.

4.4.   EDP categories

4.4.1.   For those engine categories in Table V-3 or V-4 of Annex V to Regulation (EU) 2016/1628 that have alternative values for EDP, manufacturers shall declare the applicable EDP category for each engine family at the time of EU type-approval. Such category shall be the category from Table 3.2 which most closely approximates the expected useful lives of the equipment into which the engines are expected to be installed as determined by the engine manufacturer. Manufacturers shall retain data appropriate to support their choice of EDP category for each engine family. Such data shall be supplied to the approval authority upon request.

Table 3.2

EDP categories

EDP Category	Application of Engine
Cat 1	Consumer products
Cat 2	Semi-professional products
Cat 3	Professional products

4.4.2.   The manufacturer shall demonstrate to the satisfaction of the approval authority that the declared EDP category is appropriate. Data to support a manufacturer's choice of EDP category, for a given engine family, may include but are not limited to:

—	surveys of the life spans of the equipment in which the subject engines are installed,

—	engineering evaluations of field aged engines to ascertain when engine performance deteriorates to the point where usefulness and/or reliability is impacted to a degree sufficient to necessitate overhaul or replacement,

—	warranty statements and warranty periods,

—	marketing materials regarding engine life,

—	failure reports from engine customers, and

—	engineering evaluations of the durability, in hours, of specific engine technologies, engine materials or engine designs.

ANNEX IV

Requirements with regard to emission control strategies, NOx control measures and particulate control measures

1.   Definitions abbreviations and general requirements

1.1.   For the purposes of this Annex, the following definitions and abbreviations apply:

(1)	‘diagnostic trouble code (“DTC”)’ means a numeric or alphanumeric identifier which identifies or labels a NCM and/ PCM;

(2)	‘confirmed and active DTC’ means a DTC that is stored during the time the NCD and/or PCD system concludes that a malfunction exists;

(3)	‘NCD engine family’ means a manufacturer's grouping of engines having common methods of monitoring/diagnosing NCMs;

(4)

‘NOx Control Diagnostic system (NCD)’ means a system on-board the engine which has the capability of (a) detecting a NOx Control Malfunction, (b) identifying the likely cause of NOx control malfunctions by means of information stored in computer memory and/or communicating that information off-board;

(5)	‘NOx Control Malfunction (NCM)’ means an attempt to tamper with the NOx control system of an engine or a malfunction affecting that system that might be due to tampering, that is considered by this Regulation as requiring the activation of a warning or an inducement system once detected;

(6)

‘Particulate Control Diagnostic system (PCD)’ means a system on-board the engine which has a capability of: (a) detecting a Particulate Control Malfunction, (b) identifying the likely cause of particulate control malfunctions by means of information stored in computer memory and/or communicating that information off-board;

(7)

‘Particulate Control Malfunction (PCM)’ means an attempt to tamper with the particulate after-treatment system of an engine or a malfunction affecting the particulate after-treatment system that might be due to tampering, that is considered by this Regulation as requiring the activation of a warning once detected;

(8)	‘PCD engine family’ means a manufacturer's grouping of engines having common methods of monitoring/diagnosing PCMs;

(9)	‘Scan-tool’ means an external test equipment used for off-board communication with the NCD and/or PCD system.

1.2.   Ambient temperature

Notwithstanding Article 2(7), where reference is made to ambient temperature in relation to environments other than a laboratory environment, the following provisions shall apply:

1.2.1.

For an engine installed in a test-bed, ambient temperature shall be the temperature of the combustion air supplied to the engine, upstream of any part of the engine being tested.

1.2.2.

For an engine installed in non-road mobile machinery, ambient temperature shall be the air temperature immediately outside the perimeter of the non-road mobile machinery.

2.   Technical requirements relating to emission control strategies

2.1.   This section 2 shall apply for electronically controlled engines of categories NRE, NRG, IWP, IWA, RLL and RLR, complying with ‘Stage V’ emission limits set out in Annex II to Regulation (EU) 2016/1628 and using electronic control to determine both the quantity and timing of injecting fuel or using electronic control to activate, de-activate or modulate the emission control system used to reduce NOx.

2.2.   Requirements for base emission control strategy

2.2.1.   The base emission control strategy shall be designed as to enable the engine, in normal use, to comply with the provisions of this Regulation. Normal use is not restricted to the control conditions as specified in point 2.4.

2.2.2.   Base emission control strategies are, but not limited to, maps or algorithms for controlling:

(a)	timing of fuel injection or ignition (engine timing);

(b)	exhaust gas recirculation (EGR);

(c)	SCR catalyst reagent dosing.

2.2.3.   Any base emission control strategy that can distinguish engine operation between a standardised EU type-approval test and other operating conditions and subsequently reduce the level of emission control when not operating under conditions substantially included in the EU type-approval procedure is prohibited.

2.3.   Requirements for auxiliary emission control strategy

2.3.1.   An auxiliary emission control strategy may be activated by an engine or a non-road mobile non-road mobile machinery, provided that the auxiliary emission control strategy:

2.3.1.1.

does not permanently reduce the effectiveness of the emission control system;

2.3.1.2.

operates only outside the control conditions specified in points 2.4.1, 2.4.2 or 2.4.3 for the purposes defined in point 2.3.5 and only as long as is needed for those purposes, except as permitted by points 2.3.1.3, 2.3.2 and 2.3.4;

2.3.1.3.

is activated only exceptionally within the control conditions in points 2.4.1, 2.4.2 or 2.4.3, respectively, has been demonstrated to be necessary for the purposes identified in point 2.3.5 has been approved by the approval authority, and is not activated for longer than is needed for those purposes;

2.3.1.4.

ensures a level of performance of the emission control system that is as close as possible to that provided by the base emission control strategy.

2.3.2.   Where the auxiliary emission control strategy is activated during the EU type-approval test, activation shall not be limited to occur outside the control conditions set out in point 2.4, and the purpose shall not be limited to the criteria set out in point 2.3.5.

2.3.3.   Where the auxiliary emission control strategy is not activated during the EU type-approval test, it must be demonstrated that the auxiliary emission control strategy is active only for as long as required for the purposes set out in point 2.3.5.

2.3.4.   Cold temperature operation

An auxiliary emission control strategy may be activated on an engine equipped with exhaust gas recirculation (EGR) irrespective of the control conditions in point 2.4 if the ambient temperature is below 275 K (2 °C) and one of the two following criteria is met:

(a)	intake manifold temperature is less than or equal to the temperature defined by the following equation: IMTc = PIM/15,75 + 304,4, where: IMTc is the calculated intake manifold temperature, K and PIM is the absolute intake manifold pressure in kPa;

(b)	engine coolant temperature is less than or equal to the temperature defined by the following equation: ECTc = PIM/14,004 + 325,8, where: ECTc is the calculated engine coolant temperature, K and PIM is the absolute intake manifold pressure, kPa.

2.3.5.   Except as permitted by point 2.3.2, an auxiliary emission control strategy may solely be activated for the following purposes:

(a)	by on-board signals, for protecting the engine (including air-handling device protection) and/or non-road mobile machinery into which the engine is installed from damage;

(b)	for operational safety reasons;

(c)	for prevention of excessive emissions, during cold start or warming-up, during shut-down;

(d)

if used to trade-off the control of one regulated pollutant under specific ambient or operating conditions, for maintaining control of all other regulated pollutants, within the emission limit values that are appropriate for the engine concerned. The purpose is to compensate for naturally occurring phenomena in a manner that provides acceptable control of all emission constituents.

2.3.6.   The manufacturer shall demonstrate to the technical service at the time of the EU type-approval test that the operation of any auxiliary emission control strategy complies with the provisions of this section. The demonstration shall consist of an evaluation of the documentation referred to in point 2.6.

2.3.7.   Any operation of an auxiliary emission control strategy non-compliant with points 2.3.1 to 2.3.5 is prohibited.

2.4.   Control conditions

The control conditions specify an altitude, ambient temperature and engine coolant range that determines whether auxiliary emission control strategies may generally or only exceptionally be activated in accordance with point 2.3.

The control conditions specify an atmospheric pressure which is measured as absolute atmospheric static pressure (wet or dry) (‘Atmospheric pressure’)

2.4.1.   Control conditions for engines of categories IWP and IWA:

(a)	an altitude not exceeding 500 metres (or equivalent atmospheric pressure of 95,5 kPa);

(b)	an ambient temperature within the range 275 K to 303 K (2 °C to 30 °C);

(c)	the engine coolant temperature above 343 K (70 °C).

2.4.2.   Control conditions for engines of category RLL:

(a)	an altitude not exceeding 1 000 metres (or equivalent atmospheric pressure of 90 kPa);

(b)	an ambient temperature within the range 275 K to 303 K (2 °C to 30 °C);

(c)	the engine coolant temperature above 343 K (70 °C).

2.4.3.   Control conditions for engines of categories NRE, NRG and RLR:

(a)	the atmospheric pressure greater than or equal to 82,5 kPa;

(b)

the ambient temperature within the following range: — equal to or above 266 K (– 7 °C), — less than or equal to the temperature determined by the following equation at the specified atmospheric pressure: Tc = – 0,4514 × (101,3 – Pb) + 311, where: Tc is the calculated ambient air temperature, K and Pb is the atmospheric pressure, kPa;

(c)	the engine coolant temperature above 343 K (70 °C).

2.5.   Where the engine inlet air temperature sensor is being used to estimate ambient air temperature the nominal offset between the two measurement points shall be evaluated for an engine type or engine family. Where used, the measured intake air temperature shall be adjusted by an amount equal to the nominal offset to estimate ambient temperature for an installation using the specified engine type or engine family.

The evaluation of the offset shall be made using good engineering judgement based on technical elements (calculations, simulations, experimental results, data etc.) including:

(a)	the typical categories of non-road mobile machinery into which the engine type or engine family will be installed; and,

(b)	the installation instructions provided to the OEM by the manufacturer.

A copy of the evaluation shall be made available to the approval authority upon request.

2.6.   Documentation requirements

The manufacturer shall comply with the documentation requirements laid down in point 1.4 of Part A of Annex I to Implementing Regulation (EU) 2017/656 and Appendix 2 to that Annex.

3.   Technical requirements relating to NOx control measures

3.1.   This section 3 shall apply to electronically controlled engines of categories NRE, NRG, IWP, IWA, RLL and RLR, complying with ‘stage V’ emission limits set out in Annex II to Regulation (EU) 2016/1628 and using electronic control to determine both the quantity and timing of injecting fuel or using electronic control to activate, de-activate or modulate the emission control system used to reduce NOx.

3.2.   The manufacturer shall provide complete information on the functional operational characteristics of the NOx control measures using the documents set out in Annex I to Implementing Regulation (EU) 2017/656.

3.3.   The NOx control strategy shall be operational under all environmental conditions regularly occurring in the territory of the Union, especially at low ambient temperatures.

3.4.   The manufacturer shall demonstrate that the emission of ammonia during the applicable emission test cycle of the EU type-approval procedure, when a reagent is used, does not exceed a mean value of 25 ppm for engines of category RLL and 10 ppm for engines of all other applicable categories.

3.5.   If reagent containers are installed on or connected to a non-road mobile machinery, means for taking a sample of the reagent inside the containers must be included. The sampling point must be easily accessible without requiring the use of any specialised tool or device.

3.6.   In addition to the requirements set out in points 3.2 to 3.5, the following requirements shall apply:

(a)	For engines of category NRG the technical requirements set out in Appendix 1;

(b)

For engines of category NRE: (i) the requirements set out in Appendix 2, when the engine is exclusively intended for use in the place of Stage V engines of categories IWP and IWA, in accordance with Article 4(1), point (1)(b) of Regulation (EU) 2016/1628; or (ii) the requirements set out in Appendix 1 for engines not covered by subparagraph (i);

(c)	For engines of category IWP, IWA and RLR the technical requirements set out in Appendix 2;

(d)	For engines of category RLL the technical requirements set out in Appendix 3

4.   Technical requirements relating to particulate pollutant control measures

4.1.   This section shall apply to engines of sub-categories subject to a PN limit in accordance with the ‘stage V’ emission limits set out in Annex II to Regulation (EU) 2016/1628 fitted with a particulate after-treatment system In cases where the NOx control system and the particulate control system share the same physical components (e.g. same substrate (SCR on filter), same exhaust gas temperature sensor) the requirements of this section shall not apply to any component or malfunction where, after consideration of a reasoned assessment provided by the manufacturer, the approval authority concludes that a particulate control malfunction within the scope of this section would lead to a corresponding NOx control malfunction within the scope of section 3.

4.2.   The detailed technical requirements relating to particulate pollutant control measures are specified in Appendix 4.

ANNEX V

Measurements and tests with regard to the area associated with the non-road steady-state test cycle

1.   General requirements

This Annex shall apply for electronically controlled engines of categories NRE, NRG, IWP, IWA, and RLR, complying with ‘Stage V’ emission limits set out in Annex II to Regulation (EU) 2016/1628 and using electronic control to determine both the quantity and timing of injecting fuel or using electronic control to activate, de-activate or modulate the emission control system used to reduce NOx.

This Annex sets out the technical requirements relating to the area associated with the relevant NRSC, within which the amount by which that the emissions shall be permitted to exceed the emission limits set out in Annex II is controlled.

When an engine is tested in the manner set out in test requirements of section 4 the emissions sampled at any randomly selected point within the applicable control area set out in section 2 shall not exceed the applicable emission limit values in Annex II to Regulation (EU) 2016/1628 multiplied by a factor of 2,0.

Section 3 sets out the selection by the technical service of additional measurement points from within the control area during the emission bench test, in order to demonstrate that the requirements of this section 1 have been met.

The manufacturer may request that the Technical Service excludes operating points from any of the control areas set out in section 2 during the demonstration set out in section 3. The Technical Service may grant this exclusion if the manufacturer can demonstrate that the engine is never capable of operating at such points when used in any non-road mobile non-road mobile machinery combination.

The installation instructions provided by the manufacturer to the OEM in accordance with Annex XIV shall identify the upper and lower boundaries of the applicable control area and shall include a statement to clarify that the OEM shall not install the engine in such a way that it constrains the engine to operate permanently at only speed and load points outside of the control area for the torque curve corresponding to the approved engine type or engine family.

2.   Engine control area

The applicable control area for conducting the engine test shall be the area identified in this section 2 that corresponds to the applicable NRSC for the engine being tested.

2.1.   Control area for engines tested on NRSC cycle C1

These engines operate with variable-speed and load. Different control area exclusions apply depending upon the (sub-)category and operating speed of the engine.

2.1.1.   Variable-speed engines of category NRE with maximum net power ≥ 19 kW, variable-speed engines of category IWA with maximum net power ≥ 300 kW, variable-speed engines of category RLR and variable-speed engines of category NRG.

The control area (see Figure 5.1) is defined as follows:

upper torque limit: full load torque curve;

speed range: speed A to n hi;

where:

speed A = n lo + 0,15 × (n hi – n lo);

n hi	=	high speed [see Article 1(12)];
n lo	=	low speed [see Article 1(13)].

The following engine operating conditions shall be excluded from testing:

(a)	points below 30 % of maximum torque;

(b)	points below 30 % of maximum net power.

If the measured engine speed A is within ± 3 % of the engine speed declared by the manufacturer, the declared engine speeds shall be used. If the tolerance is exceeded for any of the test speeds, the measured engine speeds shall be used.

Intermediate test points within the control area shall be determined as follows:

%torque = % of maximum torque;

;

where: n100 % is the 100 % speed for the corresponding test cycle.

Figure 5.1

Control area for variable-speed engines of category NRE with maximum net power ≥ 19 kW, variable-speed engines of category IWA with maximum net power ≥ 300 kW and variable-speed engines of category NRG

2.1.2.   Variable-speed engines of category NRE with maximum net power < 19 kW and variable-speed engines of category IWA with maximum net power < 300 kW

The control area specified in point 2.1.1 shall apply but with the additional exclusion of the engine operating conditions given in this point and illustrated in Figures 5.2 and 5.3.

(a)	for particulate matter only, if the C speed is below 2 400 r/min, points to the right of or below the line formed by connecting the points of 30 % of maximum torque or 30 % of maximum net power, whichever is greater, at the B speed and 70 % of maximum net power at the high speed;

(b)

for particulate matter only, if the C speed is at or above 2 400 r/min, points to the right of the line formed by connecting the points of 30 % of maximum torque or 30 % of maximum net power, whichever is greater, at the B speed, 50 % of maximum net power at 2 400 r/min, and 70 % of maximum net power at the high speed.

where:

speed B = n lo + 0,5 × (n hi – n lo);

speed C = n lo + 0,75 × (n hi – n lo).

n hi	=	high speed [see Article 1(12)],
n lo	=	low speed [see Article 1(13)],

If the measured engine speeds A, B and C are within ± 3 % of the engine speed declared by the manufacturer, the declared engine speeds shall be used. If the tolerance is exceeded for any of the test speeds, the measured engine speeds shall be used.

Figure 5.2

Control area for variable-speed engines of category NRE with maximum net power < 19 kW and variable-speed engines of category IWA with maximum net power < 300 kW, speed C < 2 400 rpm

Key:

1	Engine Control Area
2	All Emissions Carve-Out
3	PM Carve-Out
a	% of maximum net power
b	% of maximum torque

Figure 5.3

Control area for variable-speed engines of category NRE with maximum net power < 19 kW and variable-speed engines of category IWA with maximum net power < 300 kW, speed C ≥ 2 400 rpm

Key:

1	Engine Control Area
2	All Emissions Carve-Out
3	PM Carve-Out
a	Percent of maximum net power
b	Percent of maximum torque

2.2.   Control area for engines tested on NRSC cycles D2, E2 and G2

These engines are mainly operated very close to their designed operating speed, hence the control area is defined as:

speed	:	100 %
torque range	:	50 % to the torque corresponding to maximum power.

2.3.   Control area for engines tested on NRSC cycle E3

These engines are mainly operated slightly above and below a fixed pitch propeller curve. The control area is related to the propeller curve and has exponents of mathematical equations defining the boundaries of the control area. The control area is defined as follows:

Lower speed limit	:	0,7 × n 100 %
Upper boundary curve	:	%power = 100 × (%speed/90)3,5;
Lower boundary curve	:	%power = 70 × (%speed/100)2,5;
Upper power limit	:	Full load power curve
Upper speed limit	:	Maximum speed permitted by governor

where:

%power is % of maximum net power;

%speed is % of n 100 %

n 100 % is the 100 % speed for the corresponding test cycle.

Figure 5.4

Control area for engines tested on NRSC cycle E3

Key:

1	Lower speed limit
2	Upper boundary curve
3	Lower boundary curve
4	Full load power curve
5	Governor maximum speed curve
6	Engine Control Area

3.   Demonstration requirements

The technical service shall select random load and speed points within the control area for testing. For engines subject to point 2.1 up to three points shall be selected. For engines subject to point 2.2 one point shall be selected. For engines subject to points 2.3 or 2.4 up to two points shall be selected. The technical service shall also determine a random running order of the test points. The test shall be run in accordance with the principal requirements of the NRSC, but each test point shall be evaluated separately.

4.   Test requirements

The test shall be carried out immediately after the discrete mode NRSC as follows:

(a)

the test shall be carried out immediately after the discrete-mode NRSC as described in points (a) to (e) of point 7.8.1.2 of Annex VI but before the post test procedures (f) or after the ramped modal non-road steady-state test cycle (‘RMC’) test in points (a) to (d) of point 7.8.2.3 of Annex VI but before the post test procedures (e) as relevant;

(b)	the tests shall be carried out as required in points (b) to (e) of point 7.8.1.2 of Annex VI using the multiple filter method (one filter for each test point) for each of the test points chosen in accordance with section 3;

(c)	a specific emission value shall be calculated (in g/kWh or #/kWh as applicable) for each test point;

(d)	emissions values may be calculated on a mass basis using section 2 of Annex VII or on a molar basis using section 3 of Annex VII, but shall be consistent with the method used for the discrete-mode NRSC or RMC test;

(e)	for gaseous and PN, if applicable, summation calculations, Nmode in equation (7-63) shall be set to 1 and a weighting factor of 1 shall be used;

(f)	for particulate calculations the multiple filter method shall be used; for summation calculations, Nmode in equation (7-64) shall be set to 1 and a weighting factor of 1 shall be used.

ANNEX VI

Conduct of emission tests and requirements for measurement equipment

1.   Introduction

This Annex describes the method of determining emissions of gaseous and particulate pollutants from the engine to be tested and the specifications related to the measurement equipment. As from section 6, the numbering of this Annex is consistent with the numbering of the NRMM gtr 11 and UN R 96-03, Annex 4B. However, some points of the NRMM gtr 11 are not needed in this Annex, or are modified in accordance with the technical progress.

2.   General overview

This Annex contains the following technical provisions needed for conducting an emissions test. Additional provisions are listed in point 3.

—	Section 5: Performance requirements, including the determination of tests speeds

—	Section 6: Test conditions, including the method for accounting for emissions of crankcase gases, the method for determining and accounting for continuous and infrequent regeneration of exhaust after-treatment systems

—	Section 7: Test procedures, including the mapping of engines, the test cycle generation and the test cycle running procedure

—	Section 8: Measurement procedures, including the instrument calibration and performance checks and the instrument validation for the test

—	Section 9: Measurement equipment, including the measurement instruments, the dilution procedures, the sampling procedures and the analytical gases and mass standards

—	Appendix 1: PN measurement procedure

3.   Related annexes

—	:	Data evaluation and calculation	:	Annex VII
—	:	Test procedures for dual-fuel engines	:	Annex VIII
—	:	Reference fuels	:	Annex IX
—	:	Test cycles	:	Annex XVII

4.   General requirements

The engines to be tested shall meet the performance requirements set out in section 5 when tested in accordance with the test conditions set out in section 6 and the test procedures set out in section 7.

5.   Performance requirements

5.1.   Emissions of gaseous and particulate pollutants and of CO2 and NH3

The pollutants are represented by:

(a)	Oxides of nitrogen, NOx;

(b)	Hydrocarbons, expressed as total hydrocarbons, HC or THC;

(c)	Carbon monoxide, CO;

(d)	Particulate matter, PM;

(e)	Particle number, PN.

The measured values of gaseous and particulate pollutants and of CO2 exhausted by the engine refer to the brake-specific emissions in grams per kilowatt-hour (g/kWh).

The gaseous and particulate pollutants that shall be measured are those for which limit values are applicable to the engine sub-category being tested as set out in Annex II to Regulation (EU) 2016/1628. The results, inclusive of the deterioration factor determined according to Annex III, shall not exceed the applicable limit values.

The CO2 shall be measured and reported for all engine sub-categories as required by Article 41(4) of Regulation (EU) 2016/1628.

The mean emission of ammonia (NH3) shall additionally be measured, as required in accordance with section 3 of Annex IV, when the NOx control measures that are part of the engine emission control system include use of a reagent, and shall not exceed the values set out in that section.

The emissions shall be determined on the duty cycles (steady-state and/or transient test cycles), as described in section 7 and in Annex XVII. The measurement systems shall meet the calibration and performance checks set out in section 8 with the measurement equipment described in section 9.

Other systems or analysers may be approved by the approval authority if it is found that they yield equivalent results in accordance with point 5.1.1. The results shall be calculated according to the requirements of Annex VII.

5.1.1.   Equivalency

The determination of system equivalency shall be based on a seven-sample pair (or larger) correlation study between the system under consideration and one of the systems of this annex. ‘Results’ refer to the specific cycle weighted emissions value. The correlation testing is to be performed at the same laboratory, test cell and on the same engine, and is preferred to be run concurrently. The equivalency of the sample pair averages shall be determined by F-test and t-test statistics as described in Appendix 3 of Annex VII, obtained under the laboratory, test cell and the engine conditions described above. Outliers shall be determined in accordance with ISO 5725 and excluded from the database. The systems to be used for correlation testing shall be subject to the approval by the approval authority.

5.2.   General requirements on the test cycles

5.2.1.   The EU type-approval test shall be conducted using the appropriate NRSC and, where applicable, NRTC or LSI-NRTC, as specified in Article 24 and Annex IV to Regulation (EU) 2016/1628.

5.2.2.   The technical specifications and characteristics of the NRSC are set out in Annex XVII, Appendix 1 (discrete-mode NRSC) and Appendix 2 (ramped-modal NRSC). At the choice of the manufacturer, a NRSC test may be run as a discrete-mode NRSC or, where available, as a ramped-modal NRSC (‘RMC’) as set out in point 7.4.1.

5.2.3.   The technical specifications and characteristics of the NRTC and LSI-NRTC are set out in Appendix 3 of Annex XVII.

5.2.4.   The test cycles specified in point 7.4 and in Annex XVII are designed around percentages of maximum torque or power and test speeds that need to be determined for the correct performance of the test cycles:

(a)	100 % speed (maximum test speed (MTS) or rated speed)

(b)	Intermediate speed(s) as specified in point 5.2.5.4;

(c)	Idle speed, as specified in point 5.2.5.5.

The determination of the test speeds is set out in point 5.2.5, the use of torque and power in point 5.2.6.

5.2.5.   Test speeds

5.2.5.1.   Maximum test speed (MTS)

The MTS shall be calculated in accordance with point 5.2.5.1.1 or point 5.2.5.1.3.

5.2.5.1.1.   Calculation of MTS

In order to calculate the MTS the transient mapping procedure shall be performed in accordance with point 7.4. The MTS is then determined from the mapped values of engine speed versus power. MTS shall be calculated by means of equation (6-1), (6-2) or (6-3):

(a)	MTS = n lo + 0,95 × (n hi – n lo)	(6-1)
(b)	MTS = n i	(6-2)

with:

n i	is the average of the lowest and highest speeds at which (n 2 norm i + P 2 norm i ) is equal to 98 % of the maximum value of (n 2 norm i + P 2 norm i )

(c)

If there is only one speed at which the value of (n 2 norm i + P 2 norm i ) is equal to 98 % of the maximum value of (n 2 norm i + P 2 norm i ): MTS = n i (6-3) with: n i is the speed at which the maximum value of (n 2 norm i + P 2 norm i ) occurs. where: n = is the engine speed i = is an indexing variable that represents one recorded value of an engine map n hi = is the high speed as defined in Article 2(12), n lo = is the low speed as defined in Article 2(13), n norm i = is an engine speed normalized by dividing it by P norm i = is an engine power normalized by dividing it by Pmax = is the average of the lowest and highest speeds at which power is equal to 98 % of P max. Linear interpolation shall be used between the mapped values to determine: (a) the speeds where power is equal to 98 % of P max. If there is only one speed at which power is equal to 98 % of Pmax, shall be the speed at which Pmax occurs; (b) the speeds where (n 2 norm i + P 2 n orm i ) is equal to 98 % of the maximum value of (n 2 norm i + P 2 n orm i ).

5.2.5.1.2.   Use of a declared MTS

If the MTS calculated in accordance with point 5.2.5.1.1 or 5.2.5.1.3 is within ± 3 % of the MTS declared by the manufacturer, the declared MTS may be used for the emissions test. If the tolerance is exceeded, the measured MTS shall be used for the emissions test.

5.2.5.1.3.   Use of an adjusted MTS

If the falling part of the full load curve has a very steep edge, this may cause problems to drive the 105 % speeds of the NRTC correctly. In this case it is allowed, with prior agreement of the technical service, to use an alternative value of MTS determined using one of the following methods:

(a)	the MTS may be slightly reduced (maximum 3 %) in order to make correct driving of the NRTC possible.

(b)

Calculate an alternative MTS by means of equation (6-4): MTS = ((n max – n idle)/1,05) + n idle (6-4) where: n max = is the engine speed at which the engine governor function controls engine speed with operator demand at maximum and with zero load applied (‘maximum no-load speed’) n idle = is the idle speed

5.2.5.2.   Rated speed

The rated speed is defined in Article 3(29) of Regulation (EU) 2016/1628. Rated speed for variable-speed engines subject to an emission test shall be determined from the applicable mapping procedure set out in section 7.6. Rated speed for constant-speed engines shall be declared by the manufacturer according to the characteristics of the governor. Where an engine type equipped with alternative speeds as permitted by Article 3(21) of Regulation (EU) 2016/1628 is subject to an emission test, each alternative speed shall be declared and tested.

If the rated speed determined from the mapping procedure in section 7.6 is within ± 150 rpm of the value declared by the manufacturer for engines of category NRS provided with governor, or within ± 350 rpm or ± 4 % for engines of category NRS without governor, whichever is smaller, or within ± 100 rpm for all other engine categories, the declared value may be used. If the tolerance is exceeded, the rated speed determined from the mapping procedure shall be used.

For engines of category NRSh the 100 % test speed shall be within ± 350 rpm of the rated speed.

Optionally, MTS may be used instead of rated speed for any steady state test cycle.

5.2.5.3.   Maximum torque speed for variable-speed engines

The maximum torque speed determined from the maximum torque curve established from the applicable engine mapping procedure in point 7.6.1 or 7.6.2 shall be one of the following:

(a)	The speed at which the highest torque was recorded; or,

(b)	The average of the lowest and highest speeds at which the torque is equal to 98 % of the maximum torque. Where necessary, linear interpolation shall be used to determine the speeds at which the torque is equal to 98 % of the maximum torque.

If the maximum torque speed determined from the maximum torque curve is within ± 4 % of the maximum torque speed declared by the manufacturer for engines of category NRS or NRSh, or ± 2,5 % of the maximum torque speed declared by the manufacturer for all other engine categories, the declared value may be used for the purpose of this regulation. If the tolerance is exceeded, the maximum torque speed determined from the maximum torque curve shall be used.

5.2.5.4.   Intermediate speed

The intermediate speed shall meet one of the following requirements:

(a)	For engines that are designed to operate over a speed range on a full load torque curve, the intermediate speed shall be the maximum torque speed if it occurs between 60 % and 75 % of rated speed;

(b)	If the maximum torque speed is less than 60 % of rated speed, then the intermediate speed shall be 60 % of the rated speed;

(c)	If the maximum torque speed is greater than 75 % of the rated speed then the intermediate speed shall be 75 % of rated speed. Where the engine is only capable of operation at speeds higher than 75 % of rated speed the intermediate speed shall be the lowest speed at which the engine can be operated;

(d)	For engines that are not designed to operate over a speed range on a full-load torque curve at steady-state conditions, the intermediate speed shall be between 60 % and 70 % of the rated speed.

(e)	For engines to be tested on cycle G1, except for engines of category ATS, the intermediate speed shall be 85 % of the rated speed.

(f)	For engines of category ATS tested on cycle G1 the intermediate speed shall be 60 % or 85 % of rated speed based on which is closer to the actual maximum torque speed.

Where the MTS is used in place of rated speed for the 100 % test speed, MTS shall also replace rated speed when determining the intermediate speed.

5.2.5.5.   Idle speed

The idle speed is the lowest engine speed with minimum load (greater than or equal to zero load), where an engine governor function controls engine speed. For engines without a governor function that controls idle speed, idle speed means the manufacturer-declared value for lowest engine speed possible with minimum load. Note that warm idle speed is the idle speed of a warmed-up engine.

5.2.5.6.   Test speed for constant-speed engines

The governors of constant-speed engines may not always maintain speed exactly constant. Typically speed can decrease (0,1 to 10) % below the speed at zero load, such that the minimum speed occurs near the engine's point of maximum power. The test speed for constant-speed engines may be commanded by using the governor installed on the engine or using a test-bed speed demand where this represents the engine governor.

Where the governor installed on the engine is used the 100 % speed shall be the engine governed speed as defined in Article 2(24).

Where a test-bed speed demand signal is used to simulate the governor, the 100 % speed at zero load shall be the no-load speed specified by the manufacturer for that governor setting and the 100 % speed at full load shall be the rated speed for that governor setting. Interpolation shall be used to determine the speed for the other test modes.

Where the governor has an isochronous operation setting, or the rated speed and no-load speed declared by the manufacturer differ by no more than 3 %, a single value declared by the manufacturer may be used for the 100 % speed at all load points.

5.2.6.   Torque and Power

5.2.6.1   Torque

The torque figures given in the test cycles are percentage values that represent, for a given test mode, one of the following:

(a)	The ratio of the required torque to the maximum possible torque at the specified test speed (all cycles except D2 & E2);

(b)	The ratio of the required torque to the torque corresponding to the rated net power declared by the manufacturer (cycle D2 & E2).

5.2.6.2.   Power

The power figures given in the test cycles are percentage values that represent, for a given test mode, one of the following:

(a)	For the test cycle E3 the power figures are percentage values of the maximum net power at the 100 % speed as this cycle is based on a theoretical propeller characteristic curve for vessels driven by heavy-duty engines without limitation of length.

(b)	For the test cycle F the power figures are percentage values of the maximum net power at the given test speed, except for idle speed where it is a percentage of the maximum net power at the 100 % speed.

6.   Test Conditions

6.1.   Laboratory test conditions

The absolute temperature (T a) of the engine air at the inlet to the engine expressed in Kelvin, and the dry atmospheric pressure (p s), expressed in kPa shall be measured and the parameter f a shall be determined in accordance with the following provisions and by means of equation (6-5) or (6-6). If the atmospheric pressure is measured in a duct, negligible pressure losses shall be ensured between the atmosphere and the measurement location, and changes in the duct's static pressure resulting from the flow shall be accounted for. In multi-cylinder engines having distinct groups of intake manifolds, such as in a ‘V’ engine configuration, the average temperature of the distinct groups shall be taken. The parameter fa shall be reported with the test results.

Naturally aspirated and mechanically supercharged engines:

(6-5)

Turbocharged engines with or without cooling of the intake air:

(6-6)

6.1.1.   For the test to be considered valid both the following conditions must be met:

(a)	f a shall be within the range 0,93 ≤ f a ≤ 1,07 except as permitted by points 6.1.2 and 6.1.4;

(b)	The temperature of intake air shall be maintained to 298 ± 5 K (25 ± 5 °C), measured upstream of any engine component, except as permitted by points 6.1.3 and 6.1.4, and as required by points 6.1.5 and 6.1.6.

6.1.2.   Where the altitude of the laboratory in which the engine is being tested exceeds 600 m, with the agreement of the manufacturer f a may exceed 1,07 on the condition that p s shall not be less than 80 kPa.

6.1.3.   Where the power of the engine being tested is greater than 560 kW, with the agreement of the manufacturer the maximum value of intake air temperature may exceed 303 K (30 °C) on the condition that it shall not exceed 308 K (35 °C).

6.1.4.   Where the altitude of the laboratory in which the engine is being tested exceeds 300 m and the power of the engine being tested is greater than 560 kW, with the agreement of the manufacturer f a may exceed 1,07 on the condition that p s shall not be less than 80 kPa and the maximum value of intake air temperature may exceed 303 K (30 °C) on the condition that it shall not exceed 308 K (35 °C).

6.1.5.   In the case of an engine family of category NRS less than 19 kW exclusively consisting of engine types to be used in snow throwers, the temperature of the intake air shall be maintained between 273 K and 268 K (0 °C and – 5 °C).

6.1.6.   For engines of category SMB the temperature of the intake air shall be maintained to 263 ± 5 K (– 10 ± 5 °C), except as permitted by point 6.1.6.1.

6.1.6.1.   For engines of category SMB fitted with electronically controlled fuel injection that adjusts the fuel flow to the intake air temperature, at the choice of the manufacturer the temperature of the intake air may alternatively be maintained to 298 ± 5 K (25 ± 5 °C).

6.1.7.   It is allowed to use:

(a)

an atmospheric pressure meter whose output is used as the atmospheric pressure for an entire test facility that has more than one dynamometer test cell, as long as the equipment for handling intake air maintains ambient pressure, where the engine is tested, within ± 1 kPa of the shared atmospheric pressure;

(b)	A humidity measurement device to measure the humidity of intake air for an entire test facility that has more than one dynamometer test cell, as long as the equipment for handling intake air maintains dew point, where the engine is tested, within ± 0,5 K of the shared humidity measurement.

6.2.   Engines with charge-air cooling

(a)

A charge-air cooling system with a total intake-air capacity that represents production engines' in-use installation shall be used. Any laboratory charge-air cooling system to minimize accumulation of condensate shall be designed. Any accumulated condensate shall be drained and all drains shall be completely closed before emission testing. The drains shall be kept closed during the emission test. Coolant conditions shall be maintained as follows: (a) a coolant temperature of at least 20 °C shall be maintained at the inlet to the charge-air cooler throughout testing; (b) at the rated speed and full load, the coolant flow rate shall be set to achieve an air temperature within ± 5 °C of the value designed by the manufacturer after the charge-air cooler's outlet. The air-outlet temperature shall be measured at the location specified by the manufacturer. This coolant flow rate set point shall be used throughout testing; (c) if the engine manufacturer specifies pressure-drop limits across the charge-air cooling system, it shall be ensured that the pressure drop across the charge-air cooling system at engine conditions specified by the manufacturer is within the manufacturer's specified limit(s). The pressure drop shall be measured at the manufacturer's specified locations; When the MTS defined in point 5.2.5.1 is being used in place of rated speed to run the test cycle then this speed may be used in place of rated speed when setting the charge air temperature. The objective is to produce emission results that are representative of in-use operation. If good engineering judgment indicates that the specifications in this section would result in unrepresentative testing (such as overcooling of the intake air), more sophisticated set points and controls of charge-air pressure drop, coolant temperature, and flow rate may be used to achieve more representative results.

6.3.   Engine power

6.3.1.   Basis for emission measurement

The basis of specific emissions measurement is uncorrected net power as defined in Article 3(23) of Regulation (EU) 2016/1628.

6.3.2.   Auxiliaries to be fitted

During the test, the auxiliaries necessary for the engine operation shall be installed on the test bench according to the requirements of Appendix 2.

Where the necessary auxiliaries cannot be fitted for the test, the power they absorb shall be determined and subtracted from the measured engine power.

6.3.3.   Auxiliaries to be removed

Certain auxiliaries whose definition is linked with the operation of the non-road mobile machinery and which may be mounted on the engine shall be removed for the test.

Where auxiliaries cannot be removed, the power they absorb in the unloaded condition may be determined and added to the measured engine power (see note g in Appendix 2). If this value is greater than 3 % of the maximum power at the test speed it may be verified by the technical service. The power absorbed by auxiliaries shall be used to adjust the set values and to calculate the work produced by the engine over the test cycle in accordance with point 7.7.1.3 or point 7.7.2.3.1.

6.3.4.   Determination of auxiliary power

The power absorbed by the auxiliaries/equipment needs only be determined, if:

(a)	Auxiliaries/equipment required according to Appendix 2, are not fitted to the engine; and/or

(b)	Auxiliaries/equipment not required according to Appendix 2, are fitted to the engine.

The values of auxiliary power and the measurement/calculation method for determining auxiliary power shall be submitted by the engine manufacturer for the whole operating area of the applicable test cycles, and approved by the approval authority.

6.3.5.   Engine cycle work

The calculation of reference and actual cycle work (see point 7.8.3.4) shall be based upon engine power in accordance with point 6.3.1. In this case, P f and P r of equation (6-7) are zero, and P equals P m.

If auxiliaries/equipment are installed in accordance with points 6.3.2 and/or 6.3.3, the power absorbed by them shall be used to correct each instantaneous cycle power value P m,i, by means of equation (6-8):

P i = P m,i – P f,i + P r,i	(6-7)
P AUX = P r,i – P f,i	(6-8)

Where:

P m,i	is the measured engine power, kW
P f,i	is the power absorbed by auxiliaries/equipment to be fitted for the test but that were not installed, kW
P r,i	is the power absorbed by auxiliaries/equipment to be removed for the test but that were installed, kW.

6.4.   Engine intake air

6.4.1.   Introduction

The intake-air system installed on the engine or one that represents a typical in-use configuration shall be used. This includes the charge-air cooling and exhaust gas recirculation (EGR).

6.4.2.   Intake air pressure restriction

An engine air intake system or a test laboratory system shall be used presenting an intake air pressure restriction within ± 300 Pa of the maximum value specified by the manufacturer for a clean air cleaner at the rated speed and full load. Where this is not possible due to the design of the test laboratory air supply system a pressure restriction not exceeding the value specified by the manufacturer for a dirty filter shall be permitted subject to prior approval of the technical service. The static differential pressure of the pressure restriction shall be measured at the location and at the speed and torque set points specified by the manufacturer. If the manufacturer does not specify a location, this pressure shall be measured upstream of any turbocharger or exhaust gas recirculation (EGR) connection to the intake air system.

When the MTS defined in point 5.2.5.1 is being used in place of rated speed to run the test cycle then this speed may be used in place of rated speed when setting the intake air pressure restriction.

6.5.   Engine exhaust system

The exhaust system installed with the engine or one that represents a typical in-use configuration shall be used. The exhaust system shall conform to the requirements for exhaust emissions sampling, as set out in point 9.3. An engine exhaust system or a test laboratory system shall be used presenting a static exhaust gas back-pressure within 80 to 100 % of the maximum exhaust gas pressure restriction at the rated speed and full load. The exhaust gas pressure restriction may be set using a valve. If the maximum exhaust gas pressure restriction is 5 kPa or less, the set point shall not be more than 1,0 kPa from the maximum. When the MTS defined in point 5.2.5.1 is being used in place of rated speed to run the test cycle then this speed may be used in place of rated speed when setting the exhaust gas pressure restriction.

6.6.   Engine with exhaust after-treatment system

If the engine is equipped with an exhaust after-treatment system that is not mounted directly on the engine, the exhaust pipe shall have the same diameter as found in-use for at least four pipe diameters upstream of the expansion section containing the after-treatment device. The distance from the exhaust manifold flange or turbocharger outlet to the exhaust after-treatment system shall be the same as in the non-road mobile machinery configuration or within the distance specifications of the manufacturer. Where specified by the manufacturer the pipe shall be insulated to achieve an after-treatment inlet temperature within the specification of the manufacturer. Where other installation requirements are specified by the manufacturer these shall also be respected for the test configuration. The exhaust gas back-pressure or pressure restriction shall be set according to point 6.5. For exhaust after-treatment devices with variable exhaust gas pressure restriction, the maximum exhaust gas pressure restriction used in point 6.5 is defined at the after-treatment condition (degreening/ageing and regeneration/loading level) specified by the manufacturer. The after-treatment container may be removed during dummy tests and during engine mapping, and replaced with an equivalent container having an inactive catalyst support.

The emissions measured on the test cycle shall be representative of the emissions in the field. In the case of an engine equipped with an exhaust after-treatment system that requires the consumption of a reagent, the reagent used for all tests shall be declared by the manufacturer.

For engines of category NRE, NRG, IWP, IWA, RLR, NRS, NRSh, SMB, and ATS equipped with exhaust after-treatment systems that are regenerated on an infrequent (periodic) basis, as described in point 6.6.2, emission results shall be adjusted to account for regeneration events. In this case, the average emission depends on the frequency of the regeneration event in terms of fraction of tests during which the regeneration occurs. After-treatment systems with a regeneration process that occurs either in a sustained manner or at least once over the applicable transient (NRTC or LSI-NRTC) test cycle or RMC (‘continuous regeneration’) in accordance with point 6.6.1 do not require a special test procedure.

6.6.1.   Continuous regeneration

For an exhaust after-treatment system based on a continuous regeneration process the emissions shall be measured on an after-treatment system that has been stabilized so as to result in repeatable emissions behaviour. The regeneration process shall occur at least once during the hot-start NRTC, LSI-NRTC or NRSC test, and the manufacturer shall declare the normal conditions under which regeneration occurs (soot load, temperature, exhaust gas back-pressure, etc.). In order to demonstrate that the regeneration process is continuous, at least three hot-start runs of the NRTC, LSI-NRTC or NRSC shall be conducted. In case of hot-start NRTC, the engine shall be warmed up in accordance with point 7.8.2.1, the engine be soaked according to point 7.4.2.1(b) and the first hot-start NRTC.

The subsequent hot-start NRTC shall be started after soaking according with point 7.4.2.1(b). During the tests, exhaust gas temperatures and pressures shall be recorded (temperature before and after the exhaust after-treatment system, exhaust gas back-pressure, etc.). The exhaust after-treatment system is considered to be satisfactory if the conditions declared by the manufacturer occur during the test within a sufficient time and the emission results do not scatter by more than ± 25 % from the mean value or 0,005 g/kWh, whichever is greater.

6.6.2.   Infrequent regeneration

This provision only applies to engines equipped with an exhaust after-treatment system that is regenerated on an infrequent basis, typically occurring in less than 100 hours of normal engine operation. For those engines, either additive or multiplicative factors shall be determined for upward and downward adjustment as referred to in point 6.6.2.4 (‘adjustment factor’).

Testing and development of adjustment factors is only required for one applicable transient (NRTC or LSI-NRTC) test cycle or RMC. The factors that have been developed may be applied to results from the other applicable test cycles including discrete-mode NRSC.

In case that no suitable adjustment factors are available from testing using transient (NRTC or LSI-NRTC) test cycle or RMC then adjustment factors shall be established using an applicable discrete-mode NRSC test. Factors developed using a discrete-mode NRSC test shall only be applied to discrete-mode NRSC.

It shall not be required to conduct testing and develop adjustment factors on both RMC and discrete-mode NRSC.

6.6.2.1.   Requirement for establishing adjustment factors using NRTC, LSI-NRTC or RMC

The emissions shall be measured on at least three hot-start runs of the NRTC, LSI-NRTC or RMC, one with and two without a regeneration event on a stabilized exhaust after-treatment system. The regeneration process shall occur at least once during the NRTC, LSI-NRTC or RMC with a regeneration event. If regeneration takes longer than one NRTC, LSI-NRTC or RMC, consecutive NRTC, LSI-NRTC or RMC shall be run and emissions continued to be measured without shutting the engine off until regeneration is completed and the average of the tests shall be calculated. If regeneration is completed during any test, the test shall be continued over its entire length.

An appropriate adjustment factor shall be determined for the entire applicable cycle by means of equations (6-10) to (6-13).

6.6.2.2.   Requirement for establishing adjustment factors using discrete-mode NRSC testing

Starting with a stabilized exhaust after-treatment system the emissions shall be measured on at least three runs of each test mode of the applicable discrete-mode NRSC on which the conditions for regeneration can be met, one with and two without a regeneration event. The measurement of PM shall be conducted using the multiple filter method described in point 7.8.1.2(c). If regeneration has started but is not complete at the end of the sampling period for a specific test mode extend the sampling period shall be extended until regeneration is complete. Where there are multiple runs for the same mode an average result shall be calculated. The process shall be repeated for each test mode.

An appropriate adjustment factor shall be determined by means of equations (6-10) to (6-13) for those modes of the applicable cycle for which regeneration occurs.

6.6.2.3.   General procedure for developing infrequent regeneration adjustment factors (IRAFs)

The manufacturer shall declare the normal parameter conditions under which the regeneration process occurs (soot load, temperature, exhaust gas back-pressure, etc.). The manufacturer shall also provide the frequency of the regeneration event in terms of number of tests during which the regeneration occurs. The exact procedure to determine this frequency shall be agreed by the type approval or certification authority based upon good engineering judgement.

For a regeneration test, the manufacturer shall provide an exhaust after-treatment system that has been loaded. Regeneration shall not occur during this engine conditioning phase. As an option, the manufacturer may run consecutive tests of the applicable cycle until the exhaust after-treatment system is loaded. Emissions measurement is not required on all tests.

Average emissions between regeneration phases shall be determined from the arithmetic mean of several approximately equidistant tests of the applicable cycle. As a minimum, at least one applicable cycle as close as possible prior to a regeneration test and one applicable cycle immediately after a regeneration test shall be conducted.

During the regeneration test, all the data needed to detect regeneration shall be recorded (CO or NOx emissions, temperature before and after the exhaust after-treatment system, exhaust gas back-pressure, etc.). During the regeneration process, the applicable emission limits may be exceeded. The test procedure is schematically shown in Figure 6.1.

Figure 6.1

Scheme of infrequent (periodic) regeneration with n number of measurements and n r number of measurements during regeneration.

The average specific emission rate related to the test runs conducted according to points 6.6.2.1 or 6.6.2.2 [g/kWh or #/kWh] shall be weighted by means of equation (6-9) (see Figure 6.1):

(6-9)

Where:

n	is the number of tests in which regeneration does not occur,
n r	is the number of tests in which regeneration occurs (minimum one test),
	is the average specific emission from a test in which the regeneration does not occur [g/kWh or #/kWh]
	is the average specific emission from a test in which the regeneration occurs [g/kWh or #/kWh]

At the choice of the manufacturer and based on upon good engineering judgment, the regeneration adjustment factor k r, expressing the average emission rate, may be calculated either multiplicative or additive for all gaseous pollutants, and, where there is an applicable limit, for PM and PN, by means of equations (6-10) to (6-13):

Multiplicative (upward adjustment factor) (6-10) (downward adjustment factor) (6-11)

Additive k ru,a = e w – e (upward adjustment factor) (6-12) k rd,a = e w – e r (downward adjustment factor) (6-13)

6.6.2.4.   Application of adjustment factors

Upward adjustment factors are multiplied with or added to measured emission rates for all tests in which the regeneration does not occur. Downward adjustment factors are multiplied with or added to measured emission rates for all tests in which the regeneration occurs. The occurrence of the regeneration shall be identified in a manner that is readily apparent during all testing. Where no regeneration is identified, the upward adjustment factor shall be applied.

With reference to Annex VII and Appendix 5 of Annex VII on brake specific emission calculations, the regeneration adjustment factor:

(a)	When established for an entire weighted cycle, shall be applied to the results of the applicable weighted NRTC, LSI-NRTC and NRSC;

(b)

When established specifically for the individual modes of the applicable discrete-mode NRSC, shall be applied to the results of those modes of the applicable discrete-mode NRSC for which regeneration occurs prior to calculating the cycle weighted emission result. In this case the multiple filter method shall be used for PM measurement;

(c)	May be extended to other members of the same engine family;

(d)

May be extended to other engine families within the same engine after-treatment system family, as defined in Annex IX to Implementing Regulation (EU) 2017/656, with the prior approval of the approval authority based on technical evidence to be supplied by the manufacturer that the emissions are similar.

The following options shall apply:

(a)

A manufacturer may elect to omit adjustment factors for one or more of its engine families (or configurations) because the effect of the regeneration is small, or because it is not practical to identify when regenerations occur. In these cases, no adjustment factor shall be used, and the manufacturer is liable for compliance with the emission limits for all tests, without regard to whether a regeneration occurs;

(b)

Upon request by the manufacturer, the approval authority may account for regeneration events differently than is provided in paragraph (a). However, this option only applies to events that occur extremely infrequently, and which cannot be practically addressed using the adjustment factors described in paragraph (a).

6.7.   Cooling system

An engine cooling system with sufficient capacity to maintain the engine, with its intake-air, oil, coolant, block and head temperatures, at normal operating temperatures prescribed by the manufacturer shall be used. Laboratory auxiliary coolers and fans may be used.

6.8.   Lubricating oil

The lubricating oil shall be specified by the manufacturer and be representative of lubricating oil available in the market; the specifications of the lubricating oil used for the test shall be recorded and presented with the results of the test.

6.9.   Specification of the reference fuel

The reference fuels to be used for the test are specified in Annex IX.

The fuel temperature shall be in accordance with the manufacturer's recommendations. The fuel temperature shall be measured at the inlet to the fuel injection pump or as specified by the manufacturer, and the location of measurement recorded.

6.10.   Crankcase emissions

This section shall apply to engines of category NRE, NRG, IWP, IWA, RLR, NRS, NRSh, SMB, & ATS complying with Stage V emission limits set out in Annex II to Regulation (EU) 2016/1628.

Crankcase emissions that are discharged directly into the ambient atmosphere shall be added to the exhaust emissions (either physically or mathematically) during all emission testing.

Manufacturers taking advantage of this exception shall install the engines so that all crankcase emission can be routed into the emissions sampling system. For the purpose of this point, crankcase emissions that are routed into the exhaust gas upstream of exhaust after-treatment system during all operation are not considered to be discharged directly into the ambient atmosphere.

Open crankcase emissions shall be routed into the exhaust system for emission measurement, as follows:

(a)	The tubing materials shall be smooth-walled, electrically conductive, and not reactive with crankcase emissions. Tube lengths shall be minimized as far as possible;

(b)	The number of bends in the laboratory crankcase tubing shall be minimized, and the radius of any unavoidable bend shall be maximized;

(c)	The laboratory crankcase exhaust tubing shall meet the engine manufacturer's specifications for crankcase back-pressure;

(d)

The crankcase exhaust tubing shall connect into the raw exhaust gas downstream of any exhaust after-treatment system, downstream of any installed exhaust emissions restriction, and sufficiently upstream of any sample probes to ensure complete mixing with the engine's exhaust system before sampling. The crankcase exhaust tube shall extend into the free stream of exhaust system to avoid boundary-layer effects and to promote mixing. The crankcase exhaust tube's outlet may orient in any direction relative to the raw exhaust gas flow.

7.   Test procedures

7.1.   Introduction

This chapter describes the determination of brake specific emissions of gaseous and particulate pollutants on engines to be tested. The test engine shall be the parent engine configuration for the engine family as specified Annex IX to Implementing Regulation (EU) 2017/656.

A laboratory emission test consists of measuring emissions and other parameters for the test cycles specified in Annex XVII. The following aspects are treated:

(a)	The laboratory configurations for measuring the emissions (point 7.2);

(b)	The pre-test and post-test verification procedures (point 7.3);

(c)	The test cycles (point 7.4);

(d)	The general test sequence (point 7.5);

(e)	The engine mapping (point 7.6);

(f)	The test cycle generation (point 7.7);

(g)	The specific test cycle running procedure (point 7.8).

7.2.   Principle of emission measurement

To measure the brake-specific emissions, the engine shall be operated over the test cycles defined in point 7.4, as applicable. The measurement of brake-specific emissions requires the determination of the mass of pollutants in the exhaust emissions (i.e. HC, CO, NOx and PM), the number of particulates in the exhaust emissions (i.e. PN), the mass of CO2 in the exhaust emissions, and the corresponding engine work.

7.2.1.   Mass of constituent

The total mass of each constituent shall be determined over the applicable test cycle by using the following methods:

7.2.1.1.   Continuous sampling

In continuous sampling, the constituent's concentration is measured continuously from raw or diluted exhaust gas. This concentration is multiplied by the continuous (raw or diluted) exhaust gas flow rate at the emission sampling location to determine the constituent's flow rate. The constituent's emission is continuously summed over the test interval. This sum is the total mass of the emitted constituent.

7.2.1.2.   Batch sampling

In batch sampling, a sample of raw or diluted exhaust gas is continuously extracted and stored for later measurement. The extracted sample shall be proportional to the raw or diluted exhaust gas flow rate. Examples of batch sampling are collecting diluted gaseous emissions in a bag and collecting PM on a filter. In principal the method of emission calculation is done as follows: the batch sampled concentrations are multiplied by the total mass or mass flow (raw or dilute) from which it was extracted during the test cycle. This product is the total mass or mass flow of the emitted constituent. To calculate the PM concentration, the PM deposited onto a filter from proportionally extracted exhaust gas shall be divided by the amount of filtered exhaust gas.

7.2.1.3.   Combined sampling

Any combination of continuous and batch sampling is permitted (e.g. PM with batch sampling and gaseous emissions with continuous sampling).

Figure 6.2 illustrates the two aspects of the test procedures for measuring emissions: the equipment with the sampling lines in raw and diluted exhaust gas and the operations requested to calculate the pollutant emissions in steady-state and transient test cycles.

Figure 6.2

Test procedures for emission measurement

7.2.2.   Work determination

The work shall be determined over the test cycle by synchronously multiplying speed and brake torque to calculate instantaneous values for engine brake power. Engine brake power shall be integrated over the test cycle to determine total work.

7.3.   Verification and calibration

7.3.1.   Pre-test procedures

7.3.1.1.   Preconditioning

To achieve stable conditions, the sampling system and the engine shall be preconditioned before starting a test sequence as specified in this point.

The intent of engine preconditioning is to achieve the representativeness of emissions and emission controls over the duty cycle and to reduce bias in order to meet stable conditions for the following emission test.

Emissions may be measured during preconditioning cycles, as long as a predefined number of preconditioning cycles are performed and the measurement system has been started according to the requirements of point 7.3.1.4. The amount of preconditioning shall be identified by the engine manufacturer before starting to precondition. Preconditioning shall be performed as follows, noting that the specific cycles for preconditioning are the same ones that apply for emission testing.

7.3.1.1.1.   Preconditioning for cold-start run of NRTC

The engine shall be preconditioned by running at least one hot-start NRTC. Immediately after completing each preconditioning cycle, the engine shall be shut down and the engine-off hot-soak period shall be completed. Immediately after completing the last preconditioning cycle, the engine shall be shut down and the engine cool down described in point 7.3.1.2 shall be started.

7.3.1.1.2.   Preconditioning for hot-start run of NRTC or for LSI-NRTC

This point describes the pre-conditioning that shall be applied when it is intended to sample emissions from the hot-start NRTC without running the cold-start run of the NRTC (‘cold-start NRTC’), or for the LSI-NRTC. The engine shall be preconditioned by running at least one hot-start NRTC or LSI-NRTC as applicable. Immediately after completing each preconditioning cycle, the engine shall be shut down, and then the next cycle shall be started as soon as practical. It is recommended that the next preconditioning cycle shall be started within 60 seconds after completing the last preconditioning cycle. Where applicable, following the last pre-conditioning cycle the appropriate hot-soak (hot-start NRTC) or cool-down (LSI-NRTC) period shall apply before the engine is started for the emissions test. Where no hot-soak or cool down period applies it is recommended that the emissions test shall be started within 60 seconds after completing the last pre-conditioning cycle.

7.3.1.1.3.   Preconditioning for discrete-mode NRSC

For engine categories other than NRS and NRSh the engine shall be warmed-up and run until engine temperatures (cooling water and lube oil) have been stabilized on 50 % speed and 50 % torque for any discrete-mode NRSC test cycle other than type D2, E2, or G, or nominal engine speed and 50 % torque for any discrete-mode NRSC test cycle D2, E2 or G. The 50 % speed shall be calculated in accordance with point 5.2.5.1 in the case of an engine where MTS is used for the generation of test speeds, and calculated in accordance with point 7.7.1.3 in all other cases. 50 % torque is defined as 50 % of the maximum available torque at this speed. The emissions test shall be started without stopping the engine.

For engine categories NRS and NRSh the engine shall be warmed up according to the recommendation of the manufacturer and good engineering judgment. Before emission sampling can start, the engine shall be running on mode 1 of the appropriate test cycle until engine temperatures have been stabilized. The emissions test shall be started without stopping the engine.

7.3.1.1.4.   Preconditioning for RMC

The engine manufacturer shall select one of the following pre-conditioning sequences (a) or (b). The engine shall be pre-conditioned according to the chosen sequence.

(a)

The engine shall be preconditioned by running at least the second half of the RMC, based on the number of test modes. The engine shall not be shut down between cycles. Immediately after completing each preconditioning cycle, the next cycle (including the emission test) shall be started as soon as practical. Where possible, it is recommended that the next cycle be started within 60 seconds after completing the last preconditioning cycle.

(b)

The engine shall be warmed-up and run until engine temperatures (cooling water and lube oil) have been stabilized on 50 % speed and 50 % torque for any RMC test cycle other than type D2, E2, or G, or nominal engine speed and 50 % torque for any RMC test cycle D2, E2 or G. The 50 % speed shall be calculated in accordance with point 5.2.5.1 in the case of an engine where MTS is used for the generation of test speeds, and be calculated in accordance with point 7.7.1.3 in all other cases. 50 % torque is defined as 50 % of the maximum available torque at this speed.

7.3.1.1.5.   Engine cool-down (NRTC)

A natural or forced cool-down procedure may be applied. For forced cool-down, good engineering judgment shall be used to set up systems to send cooling air across the engine, to send cool oil through the engine lubrication system, to remove heat from the coolant through the engine cooling system, and to remove heat from an exhaust after-treatment system. In the case of a forced after-treatment cool down, cooling air shall not be applied until the exhaust after-treatment system has cooled below its catalytic activation temperature. Any cooling procedure that results in unrepresentative emissions is not permitted.

7.3.1.2.   Verification of HC contamination

If there is any presumption of an essential HC contamination of the exhaust gas measuring system, the contamination with HC may be checked with zero gas and the hang-up may then be corrected. If the amount of contamination of the measuring system and the background HC system has to be checked, it shall be conducted within 8 hours of starting each test-cycle. The values shall be recorded for later correction. Before this check, the leak check has to be performed and the FID analyzer has to be calibrated.

7.3.1.3.   Preparation of measurement equipment for sampling

The following steps shall be taken before emission sampling begins:

(a)	Leak checks shall be performed within 8 hours prior to emission sampling according to point 8.1.8.7;

(b)	For batch sampling, clean storage media shall be connected, such as evacuated bags or tare-weighed filters;

(c)	All measurement instruments shall be started according to the instrument manufacturer's instructions and good engineering judgment;

(d)	Dilution systems, sample pumps, cooling fans, and the data-collection system shall be started;

(e)	The sample flow rates shall be adjusted to desired levels, using bypass flow, if desired;

(f)	Heat exchangers in the sampling system shall be pre-heated or pre-cooled to within their operating temperature ranges for a test;

(g)	Heated or cooled components such as sample lines, filters, chillers, and pumps shall be allowed to stabilize at their operating temperatures;

(h)	Exhaust gas dilution system flow shall be switched on at least 10 minutes before a test sequence;

(i)	Calibration of gas analyzers and zeroing of continuous analyzers shall be carried out according to the procedure of the next point 7.3.1.4;

(j)	Any electronic integrating devices shall be zeroed or re-zeroed, before the start of any test interval.

7.3.1.4.   Calibration of gas analyzers

Appropriate gas analyzer ranges shall be selected. Emission analyzers with automatic or manual range switching are allowed. During a test using transient (NRTC or LSI-NRTC) test cycles or RMC and during a sampling period of a gaseous emission at the end of each mode for discrete-mode NRSC testing, the range of the emission analyzers may not be switched. Also the gains of an analyzer's analogue operational amplifier(s) may not be switched during a test cycle.

All continuous analyzers shall be zeroed and spanned using internationally-traceable gases that meet the specifications of point 9.5.1. FID analyzers shall be spanned on a carbon number basis of one (C1).

7.3.1.5.   PM filter preconditioning and tare weighing

The procedures for PM filter preconditioning and tare weighing shall be followed according to point 8.2.3.

7.3.2.   Post-test procedures

The following steps shall be taken after emission sampling is complete:

7.3.2.1.   Verification of proportional sampling

For any proportional batch sample, such as a bag sample or PM sample, it shall be verified that proportional sampling was maintained according to point 8.2.1. For the single filter method and the discrete steady-state test cycle, effective PM weighting factor shall be calculated. Any sample that does not fulfil the requirements of point 8.2.1 shall be voided.

7.3.2.2.   Post-test PM conditioning and weighing

Used PM sample filters shall be placed into covered or sealed containers or the filter holders shall be closed, in order to protect the sample filters against ambient contamination. Thus protected, the loaded filters have to be returned to the PM-filter conditioning chamber or room. Then the PM sample filters shall be conditioned and weighted accordingly to point 8.2.4 (PM filter post-conditioning and total weighing procedures).

7.3.2.3.   Analysis of gaseous batch sampling

As soon as practical, the following shall be performed:

(a)	All batch gas analyzers shall be zeroed and spanned no later than 30 minutes after the test cycle is complete or during the soak period if practical to check if gaseous analyzers are still stable;

(b)	Any conventional gaseous batch samples shall be analyzed no later than 30 minutes after the hot-start NRTC is complete or during the soak period;

(c)	The background samples shall be analyzed no later than 60 minutes after the hot-start NRTC is complete.

7.3.2.4.   Drift verification

After quantifying exhaust gas, drift shall be verified as follows:

(a)	For batch and continuous gas analyzers, the mean analyzer value shall be recorded after stabilizing a zero gas to the analyzer. Stabilization may include time to purge the analyzer of any sample gas, plus any additional time to account for analyzer response;

(b)	The mean analyzer value shall be recorded after stabilizing the span gas to the analyzer. Stabilization may include time to purge the analyzer of any sample gas, plus any additional time to account for analyzer response;

(c)	These data shall be used to validate and correct for drift as described in point 8.2.2.

7.4.   Test cycles

The EU type-approval test shall be conducted using the appropriate NRSC and, where applicable, NRTC or LSI-NRTC, specified in Article 23 and Annex IV to Regulation (EU) 2016/1628. The technical specifications and characteristics of the NRSC, NRTC and LSI-NRTC are laid down in Annex XVII and the method for determination of the load and speed settings for these test cycles set out in section 5.2.

7.4.1.   Steady-state test cycles

Non-road steady-state test cycles (NRSC) are specified in Appendices 1 and 2 of Annex XVII as a list of discrete-modes NRSC (operating points), where each operating point has one value of speed and one value of torque. A NRSC shall be measured with a warmed up and running engine according to manufacturer's specification. At the choice of the manufacturer, a NRSC may be run as a discrete-mode NRSC or a RMC, as explained in points 7.4.1.1 and 7.4.1.2. It shall not be required to conduct an emission test according to both points 7.4.1.1 and 7.4.1.2.

7.4.1.1.   Discrete-mode NRSC

The discrete-mode NRSC are hot running cycles where emissions shall be started to be measured after the engine is started, warmed up and running as specified in point 7.8.1.2. Each cycle consists of a number of speed and load modes (with the respective weighing factor for each mode) which cover the typical operating range of the specified engine category.

7.4.1.2.   Ramped modal NRSC

The RMC are hot running cycles where emissions shall be started to be measured after the engine is started, warmed up and running as specified in point 7.8.2.1. The engine shall be continuously controlled by the test bed control unit during the RMC. The gaseous and particulate emissions shall be measured and sampled continuously during the RMC in the same way as in a transient (NRTC or LSI-NRTC) test cycles.

An RMC is intended to provide a method for performing a steady-state test in a pseudo-transient manner. Each RMC consists of a series of steady state modes with a linear transition between them. The relative total time at each mode and its preceding transition match the weighting of the discrete-mode NRSC. The change in engine speed and load from one mode to the next one has to be linearly controlled in a time of 20 ± 1 seconds. The mode change time is part of the new mode (including the first mode). In some cases modes are not run in the same order as the discrete-mode NRSC or are split to prevent extreme changes in temperature.

7.4.2.   Transient (NRTC and LSI-NRTC) test cycles

The non-road transient cycle for engines of category NRE (NRTC) and the non-road transient cycle for large spark ignition engines of category NRS (LSI-NRTC) are each specified in Appendix 3 of Annex XVII as a second-by-second sequence of normalized speed and torque values. In order to perform the test in an engine test cell, the normalized values shall be converted to their equivalent reference values for the individual engine to be tested, based on specific speed and torque values identified in the engine-mapping curve. The conversion is referred to as denormalization, and the resulting test cycle is the reference NRTC or LSI-NRTC test cycle of the engine to be tested (see point 7.7.2).

7.4.2.1.   Test sequence for NRTC

A graphical display of the normalized NRTC dynamometer schedule is shown in Figure 6.3.

Figure 6.3

NRTC normalized dynamometer schedule

The NRTC shall be run twice after completion of pre-conditioning (see point 7.3.1.1.1) in accordance with the following procedure:

(a)

the cold start after the engine and exhaust after-treatment systems have cooled down to room temperature after natural engine cool down, or the cold start after forced cool down and the engine, coolant and oil temperatures, exhaust after-treatment systems and all engine control devices are stabilized between 293 K and 303 K (20 °C and 30 °C). The measurement of the cold start emissions shall be started with the start of the cold engine;

(b)	the hot soak period shall commence immediately upon completion of the cold start phase. The engine shall be shut-down and conditioned for the hot-start run by soaking it for 20 minutes ± 1 minute;

(c)

the hot-start run shall be started immediately after the soak period with the cranking of the engine. The gaseous analyzers shall be switched on at least 10 seconds before the end of the soak period to avoid switching signal peaks. The measurement of emissions shall be started in parallel with the start of the hot-start NRTC, including the cranking of the engine.

Brake specific emissions expressed in (g/kWh) shall be determined by using the procedures set out in this section for both the cold-start and hot-start NRTC. Composite weighted emissions shall be computed by weighting the cold-start run results by 10 % and the hot-start run results by 90 % as detailed in Annex VII.

7.4.2.2.   Test sequence for LSI-NRTC

The LSI-NRTC shall be run once as a hot-start run after completion of pre-conditioning (see point 7.3.1.1.2) in accordance with the following procedure:

(a)	the engine shall be started and operated for the first 180 seconds of the duty cycle, then operated at idle without load for 30 seconds. Emissions shall not be measured during this warm-up sequence.

(b)	At the end of the 30-second idling period, emissions measurement shall be started and the engine be operated over the entire duty cycle from the beginning (time 0 sec).

Brake specific emissions expressed in (g/kWh) shall be determined by using the procedures of Annex VII.

If the engine was already operating before the test, use good engineering judgment to let the engine cool down enough so measured emissions will accurately represent those from an engine starting at room temperature. For example, if an engine starting at room temperature warms up enough in three minutes to start closed-loop operation and achieve full catalyst activity, then minimal engine cooling is necessary before starting the next test.

With the prior agreement of the technical service, the engine warm-up procedure may include up to 15 minutes of operation over the duty cycle.

7.5.   General test sequence

To measure engine emissions the following steps have to be performed:

(a)	The engine test speeds and test loads have to be defined for the engine to be tested by measuring the max torque (for constant-speed engines) or max torque curve (for variable-speed engines) as function of the engine speed;

(b)	Normalized test cycles have to be denormalized with the torque (for constant-speed engines) or speeds and torques (for variable-speed engines) found in the previous point 7.5(a);

(c)	The engine, equipment, and measurement instruments shall be prepared for the following emission test or test series (cold-start run and hot-start run) in advance;

(d)	Pre-test procedures shall be performed to verify proper operation of certain equipment and analyzers. All analysers have to be calibrated. All pre-test data shall be recorded;

(e)	The engine shall be started (NRTC) or kept running (steady-state cycles and LSI-NRTC) at the beginning of the test cycle and the sampling systems shall be started at the same time;

(f)	Emissions and other required parameters shall be measured or recorded during sampling time (for NRTC, LSI-NRTC and RMC throughout the whole test cycle);

(g)	Post-test procedures shall be performed to verify proper operation of certain equipment and analyzers;

(h)	PM filter(s) shall be pre-conditioned, weighed (empty weight), loaded, re-conditioned, again weighed (loaded weight) and then samples shall be evaluated according to pre- (para. 7.3.1.5) and post-test (para. 7.3.2.2) procedures;

(i)	Emission test results shall be evaluated.

Figure 6.4 gives an overview about the procedures needed to conduct NRMM test cycles with measuring exhaust engine emissions.

Figure 6.4

Test sequence

7.5.1.   Engine starting, and restarting

7.5.1.1.   Engine start

The engine shall be started:

(a)	As recommended in the end-users' instructions using a production starter motor or air-start system and either an adequately charged battery, a suitable power supply or a suitable compressed air source; or

(b)	By using the dynamometer to crank the engine until it starts. Typically operate the engine within ± 25 % of its typical in-use cranking speed or start the engine by linearly increasing the dynamometer speed from zero to 100 min– 1 below low idle speed but only until the engine starts.

Cranking shall be stopped within 1 s of starting the engine. If the engine does not start after 15 s of cranking, cranking shall be stopped and the reason for the failure to start determined, unless the end-users' instructions or the service-repair manual describes a longer cranking time as normal.

7.5.1.2.   Engine stalling

(a)	If the engine stalls anywhere during the cold-start NRTC, the test shall be voided;

(b)	If the engine stalls anywhere during the hot-start NRTC, the test shall be voided. The engine shall be soaked according to point 7.4.2.1(b), and the hot-start run repeated. In this case, the cold-start run does not need to be repeated;

(c)	If the engine stalls anywhere during the LSI-NRTC, the test shall be voided.

(d)

If the engine stalls anywhere during the NRSC (discrete or ramped), the test shall be voided and be repeated beginning with the engine warm-up procedure. In the case of PM measurement utilizing the multi-filter method (one sampling filter for each operating mode), the test shall be continued by stabilizing the engine at the previous mode for engine temperature conditioning and then initiating measurement with the mode where the engine stalled.

7.5.1.3   Engine operation

The ‘operator’ may be a person (i.e., manual), or a governor (i.e., automatic) that mechanically or electronically signals an input that demands engine output. Input may be from an accelerator pedal or signal, a throttle-control lever or signal, a fuel lever or signal, a speed lever or signal, or a governor set point or signal.

7.6.   Engine mapping

Before starting the engine mapping, the engine shall be warmed up and towards the end of the warm up it shall be operated for at least 10 minutes at maximum power or according to the recommendation of the manufacturer and good engineering judgement in order to stabilize the engine coolant and lube oil temperatures. When the engine is stabilized, the engine mapping shall be performed.

Where the manufacturer intends to use the torque signal broadcast by the electronic control unit, of engines so equipped, during the conduct of in-service monitoring tests according to Delegated Regulation (EU) 2017/655 on monitoring of emissions of in-service engines, the verification set out in Appendix 3 shall additionally be performed during the engine mapping.

Except constant-speed engines, engine mapping shall be performed with fully open fuel lever or governor using discrete speeds in ascending order. The minimum and maximum mapping speeds are defined as follows:

Minimum mapping speed	=	warm idle speed
Maximum mapping speed	=	n hi × 1,02 or speed where max torque drops off to zero, whichever is smaller.

Where:

n hi is the high speed, as defined in Article 2(12).

If the highest speed is unsafe or unrepresentative (e.g., for ungoverned engines), good engineering judgement shall be used to map up to the maximum safe speed or the maximum representative speed.

7.6.1.   Engine mapping for variable-speed NRSC

In the case of engine mapping for a variable-speed NRSC (only for engines which have not to run the NRTC or LSI-NRTC cycle), good engineering judgment shall be used to select a sufficient number of evenly spaced set-points. At each set-point, speed shall be stabilized and torque allowed to stabilize at least for 15 seconds. The mean speed and torque shall be recorded at each set-point. It is recommended that the mean speed and torque are calculated using the recorded data from the last 4 to 6 seconds. Linear interpolation shall be used to determine the NRSC test speeds and torques if needed. When engines are additionally required to run an NRTC or LSI-NRTC, the NRTC engine mapping curve shall be used to determine steady-state test speeds and torques.

At the choice of the manufacturer the engine mapping may alternatively be conducted according to the procedure in point 7.6.2.

7.6.2.   Engine mapping for NRTC and LSI-NRTC

The engine mapping shall be performed according to the following procedure:

(a)

The engine shall be unloaded and operated at idle speed; (i) For engines with a low-speed governor, the operator demand shall be set to the minimum, the dynamometer or another loading device shall be used to target a torque of zero on the engine's primary output shaft and the engine shall be allowed to govern the speed. This warm idle speed shall be measured; (ii) For engines without a low-speed governor, the dynamometer shall be set to target a torque of zero on the engine's primary output shaft, and the operator demand shall be set to control the speed to the manufacturer-declared lowest engine speed possible with minimum load (also known as manufacturer-declared warm idle speed); (iii) The manufacturer declared idle torque may be used for all variable-speed engines (with or without a low-speed governor), if a nonzero idle torque is representative of in-use operation;

(b)

Operator demand shall be set to maximum and engine speed shall be controlled to between warm idle and 95 % of its warm idle speed. For engines with reference duty cycles, which lowest speed is greater than warm idle speed, the mapping may be started at between the lowest reference speed and 95 % of the lowest reference speed;

(c)

The engine speed shall be increased at an average rate of 8 ± 1 min– 1/s or the engine shall be mapped by using a continuous sweep of speed at a constant rate such that it takes 4 to 6 min to sweep from minimum to maximum mapping speed. The mapping speed range shall be started between warm idle and 95 % of warm idle and ended at the highest speed above maximum power at which less than 70 % of maximum power occurs. If this highest speed is unsafe or unrepresentative (e.g., for ungoverned engines), good engineering judgment shall be used to map up to the maximum safe speed or the maximum representative speed. Engine speed and torque points shall be recorded at a sample rate of at least 1 Hz;

(d)

If a manufacturer believes that the above mapping techniques are unsafe or unrepresentative for any given engine, alternate mapping techniques may be used. These alternate techniques shall satisfy the intent of the specified mapping procedures to determine the maximum available torque at all engine speeds achieved during the test cycles. Deviations from the mapping techniques specified in this section for reasons of safety or representativeness shall be approved by the approval authority along with the justification for their use. In no case, however, the torque curve shall be run by descending engine speeds for governed or turbocharged engines;

(e)

An engine need not be mapped before each and every test cycle. An engine shall be remapped if: (i) an unreasonable amount of time has transpired since the last map, as determined by good engineering judgment; or (ii) physical changes or recalibrations have been made to the engine which potentially affect engine performance; or (iii) the atmospheric pressure near the engine's air inlet is not within ± 5 kPa of the value recorded at the time of the last engine map.

7.6.3.   Engine mapping for constant-speed NRSC

The engine may be operated with a production constant-speed governor or a constant-speed governor maybe simulated by controlling engine speed with an operator demand control system. Either isochronous or speed-droop governor operation shall be used, as appropriate.

7.6.3.1.   Rated power check for engines to be tested on cycles D2 or E2

The following check shall be conducted:

(a)	With the governor or simulated governor controlling speed using operator demand the engine shall be operated at the rated speed and the rated power for as long as required to achieve stable operation;

(b)

The torque shall be increased until the engine is unable to maintain the governed speed. The power at this point shall be recorded. Before this check is performed the method to safely determine when this point has been reached shall be agreed between the manufacturer and the technical service conducting the check, depending upon the characteristics of the governor. The power recorded at point (b) shall not exceed the rated power as defined in Article 3(25) of Regulation (EU) 2016/1628 by more than 12,5 %. If this value is exceeded the manufacturer shall revise the declared rated power.

If the specific engine being tested is unable to perform this check due to risk of damage to the engine or dynamometer the manufacturer shall present to the approval authority robust evidence that maximum power does not exceed the rated power by more than 12,5 %.

7.6.3.2.   Mapping procedure for constant-speed NRSC

(a)	With the governor or simulated governor controlling speed using operator demand, the engine shall be operated at no-load governed speed (at high speed, not low idle) for at least 15 seconds, unless the specific engine is unable to perform this task;

(b)

The dynamometer shall be used to increase torque at a constant rate. The map shall be conducted such that it takes no less than 2 min to sweep from no-load governed speed to the torque corresponding to rated power for engines to be tested on cycle D2 or E2 or to maximum torque in the case of other constant-speed test cycles. During the engine mapping actual speed and torque shall be recorded with at least 1 Hz;

(c)	In case of a constant-speed engine with a governor that can be reset to alternative speeds, the engine shall be tested at each applicable constant-speed.

For constant-speed engines good engineering judgment shall be used in agreement with the approval authority to apply other methods to record torque and power at the defined operating speed(s).

For engines tested on cycles other than D2 or E2, when both measured and declared values are available for the maximum torque, the declared value may be used instead of the measured value if it is between 95 and 100 % of the measured value.

7.7.   Test cycle generation

7.7.1.   Generation of NRSC

This point shall be used to generate the engine speeds and loads over which the engine shall be operated during steady-state tests with discrete-mode NRSC or RMC.

7.7.1.1.   Generation of NRSC test speeds for engines tested with both NRSC and either NRTC or LSI-NRTC.

For engines that are tested with either NRTC or LSI-NRTC in addition to a NRSC, the MTS specified in point 5.2.5.1 shall be used as the 100 % speed for both transient and steady state tests.

The MTS shall be used in place of rated speed when determining intermediate speed in accordance with point 5.2.5.4.

The idle speed shall be determined in accordance with point 5.2.5.5.

7.7.1.2.   Generation of NRSC test speeds for engines only tested with NRSC

For engines that are not tested with a transient (NRTC or LSI-NRTC) test cycle, the rated speed specified in point 5.2.5.3 shall be used as the 100 % speed.

The rated speed shall be used to determine the intermediate speed in accordance with point 5.2.5.4. If the NRSC specifies additional speeds as a percentage they shall be calculated as a percentage of the rated speed.

The idle speed shall be determined in accordance with point 5.2.5.5.

With prior approval of the technical service, MTS may be used instead of rated speed for the generation of test speeds in this point.

7.7.1.3.   Generation of NRSC load for each test mode

The per cent load for each test mode of the chosen test cycle shall be taken from the appropriate NRSC Table of Appendix 1 or 2 of Annex XVII. Depending upon the test cycle, the per cent load in these Tables is expressed as either power or torque in accordance with point 5.2.6 and in the footnotes for each Table.

The 100 % value at a given test speed shall be the measured or declared value taken from the mapping curve generated in accordance with point 7.6.1, point 7.6.2 or point 7.6.3 respectively, expressed as power (kW).

The engine setting for each test mode shall be calculated by means of equation (6-14):

(6-14)

Where:

S	is the dynamometer setting in kW
P max	is the maximum observed or declared power at the test speed under the test conditions (specified by the manufacturer) in kW
P AUX	is the declared total power absorbed by auxiliaries as defined in equation (6-8) (see point 6.3.5) at the specified test speed in kW
L	is per cent torque

A warm minimum torque that is representative of in-use operation may be declared and used for any load point that would otherwise fall below this value if the engine type will not normally operate below this minimum torque, for example because it will be connected to a non-road mobile machinery that does not operate below a certain minimum torque.

In the case of cycles E2 and D2 the manufacturer shall declare the rated power and these shall be used as 100 % power when generating the test cycle.

7.7.2.   Generation of NRTC & LSI-NRTC speed and load for each test point (denormalization)

This point shall be used to generate the corresponding engine speeds and loads over which the engine shall be operated during NRTC or LSI-NRTC tests. Appendix 3 of Annex XVII defines applicable test cycles in a normalized format. A normalized test cycle consists of a sequence of paired values for speed and torque %.

Normalized values of speed and torque shall be transformed using the following conventions:

(a)	The normalized speed shall be transformed into a sequence of reference speeds, n ref, in accordance with point 7.7.2.2;

(b)	The normalized torque is expressed as a percentage of the mapped torque from the curve generated according to point 7.6.2 at the corresponding reference speed. These normalized values shall be transformed into a sequence of reference torques, T ref, according to point 7.7.2.3;

(c)	The reference speed and reference torque values expressed in coherent units are multiplied to calculate the reference power values.

7.7.2.1.   Reserved

7.7.2.2.   Denormalization of engine speed

The engine speed shall be denormalized using by means of equation (6-15):

(6-15)

Where:

n ref	is the reference speed
MTS	is the maximum test speed
n idle	is the idle speed
%speed	is the value of NRTC or LSI-NRTC normalized speed taken from Appendix 3 of Annex XVII.

7.7.2.3   Denormalization of engine torque

The torque values in the engine dynamometer schedule of Appendix 3 of Annex XVII. are normalized to the maximum torque at the respective speed. The torque values of the reference cycle shall be denormalized, using the mapping curve determined according to point 7.6.2, by means of equation (6-16):

(6-16)

for the respective reference speed as determined in point 7.7.2.2

Where:

T ref	is the reference torque for the respective reference speed
max.torque	is the maximum torque for the respective test speed taken from the engine mapping performed in accordance with point 7.6.2 adjusted where necessary in accordance with point 7.7.2.3.1
%torque	is the value of NRTC or LSI-NRTC normalized torque taken from Appendix 3 of Annex XVII

(a)   Declared minimum torque

A minimum torque that is representative of in-use operation may be declared. For example, if the engine is typically connected to a non-road mobile machinery that does not operate below a certain minimum torque, this torque may be declared and used for any load point that would otherwise fall below this value.

(b)   Adjustment of engine torque due to auxiliaries fitted for the emissions test

Where auxiliaries are fitted in accordance with Appendix 2 there shall be no adjustment to the maximum torque for the respective test speed taken from the engine mapping performed according to point 7.6.2.

Where, according to points 6.3.2 or 6.3.3 necessary auxiliaries that should have been fitted for the test are not installed, or auxiliaries that should have been removed for the test are installed, the value of T max shall be adjusted by means of equation (6-17).

T max = T map – T AUX

(6-17)

with:

TAUX = Tr – Tf

(6-18)

where:

T map	is the unadjusted maximum torque for the respective test speed taken from the engine mapping performed in accordance with point 7.6.2
T f	is the torque required to drive auxiliaries that should have been fitted but were not installed for the test
Tr	is the torque required to drive auxiliaries that should have been removed for the test but were installed for the test

7.7.2.4.   Example of denormalization procedure

As an example, the following test point shall be denormalized:

% speed = 43 %

% torque = 82 %

Given the following values:

MTS = 2 200 min– 1

n idle = 600 min– 1

results in

With the maximum torque of 700 Nm observed from the mapping curve at 1 288 min– 1

7.8.   Specific test cycle running procedure

7.8.1.   Emission test sequence for discrete-mode NRSC

7.8.1.1.   Engine warming-up for steady state discrete-mode NRSC

Pre-test procedure according to point 7.3.1 shall be performed, including analyzer calibration. The engine shall be warmed-up using the pre-conditioning sequence in point 7.3.1.1.3. Immediately from this engine conditioning point, the test cycle measurement starts.

7.8.1.2.   Performing discrete-mode NRSC

(a)	The test shall be performed in ascending order of mode numbers as set out for the test cycle (see Appendix 1 of Annex XVII);

(b)

Each mode has a mode length of at least 10 minutes, except when testing spark ignition engines using cycles G1, G2 or G3 where each mode has a length of at least 3 minutes. In each mode the engine shall be stabilized for at least 5 minutes and emissions shall be sampled for 1-3 minutes for gaseous emissions and, where there is an applicable limit, PN at the end of each mode, except when testing spark ignition engines using cycles G1, G2 or G3 where emissions shall be sampled for at least the last 2 minutes of the respective test mode. Extended time of sampling is permitted to improve the accuracy of PM sampling; The mode length shall be recorded and reported.

(c)

The PM sampling may be done either with the single filter method or with the multiple filter method. Since the results of the methods may differ slightly, the method used shall be declared with the results; For the single filter method the modal weighting factors specified in the test cycle procedure and the actual exhaust gas flow shall be taken into account during sampling by adjusting sample flow rate and/or sampling time, accordingly. It is required that the effective weighing factor of the PM sampling is within ± 0,005 of the weighing factor of the given mode; Sampling shall be conducted as late as possible within each mode. For the single filter method, the completion of PM sampling shall be coincident within ± 5 s with the completion of the gaseous emission measurement. The sampling time per mode shall be at least 20 s for the single filter method and at least 60 s for the multi-filter method. For systems without bypass capability, the sampling time per mode shall be at least 60 s for single and multiple filter methods;

(d)	The engine speed and load, intake air temperature, fuel flow and where applicable air or exhaust gas flow shall be measured for each mode at the same time interval which is used for the measurement of the gaseous concentrations; Any additional data required for calculation shall be recorded.

(e)

If the engine stalls or the emission sampling is interrupted at any time after emission sampling begins for a discrete-mode NRSC and the single filter method, the test shall be voided and be repeated beginning with the engine warm-up procedure. In the case of PM measurement utilizing the multi-filter method (one sampling filter for each operating mode), the test shall be continued by stabilizing the engine at the previous mode for engine temperature conditioning and then initiating measurement with the mode where the engine stalled;

(f)	Post-test procedures according to point 7.3.2 shall be performed.

7.8.1.3.   Validation criteria

During each mode of the given steady-state test cycle after the initial transition period, the measured speed shall not deviate from the reference speed for more than ± 1 % of rated speed or ± 3 min– 1, whichever is greater except for idle which shall be within the tolerances declared by the manufacturer. The measured torque shall not deviate from the reference torque for more than ± 2 % of the maximum torque at the test speed.

7.8.2.   Emission test sequence for RMC

7.8.2.1.   Engine warming-up

Pre-test procedure according to point 7.3.1 shall be performed, including analyzer calibration. The engine shall be warmed-up using the pre-conditioning sequence in point 7.3.1.1.4. Immediately after this engine conditioning procedure, if the engine speed and torque are not already set for the first mode of the test they shall be changed in a linear ramp of 20 ± 1 s to the first mode of the test. In between 5 to 10 s after the end of the ramp, the test cycle measurement shall start.

7.8.2.2.   Performing an RMC

The test shall be performed in the order of mode numbers as set out for the test cycle (see Appendix 2 of Annex XVII) Where there is no RMC available for the specified NRSC the discrete-mode NRSC procedure set out in point 7.8.1 shall be followed.

The engine shall be operated for the prescribed time in each mode. The transition from one mode to the next shall be done linearly in 20 s ± 1 s following the tolerances prescribed in point 7.8.2.4.

For RMC, reference speed and torque values shall be generated at a minimum frequency of 1 Hz and this sequence of points shall be used to run the cycle. During the transition between modes, the denormalized reference speed and torque values shall be linearly ramped between modes to generate reference points. The normalized reference torque values shall not be linearly ramped between modes and then denormalized. If the speed and torque ramp runs through a point above the engine's torque curve, it shall be continued to command the reference torques and it shall be allowed for the operator demand to go to maximum.

Over the whole RMC (during each mode and including the ramps between the modes), the concentration of each gaseous pollutant shall be measured and where there is an applicable limit the PM and PN be sampled. The gaseous pollutants may be measured raw or diluted and be recorded continuously; if diluted, they can also be sampled into a sampling bag. The particulate sample shall be diluted with conditioned and clean air. One sample over the complete test procedure shall be taken, and, in the case of PM collected on a single PM sampling filter.

For calculation of the brake specific emissions, the actual cycle work shall be calculated by integrating actual engine power over the complete cycle.

7.8.2.3.   Emission test sequence

(a)	Execution of the RMC, sampling exhaust gas, recording data, and integrating measured values shall be started simultaneously;

(b)	Speed and torque shall be controlled to the first mode in the test cycle;

(c)	If the engine stalls anywhere during the RMC execution, the test shall be voided. The engine shall be pre-conditioned and the test repeated;

(d)

At the end of the RMC, sampling shall be continued, except for PM sampling, operating all systems to allow system response time to elapse. Then all sampling and recording shall be stopped, including the recording of background samples. Finally, any integrating devices shall be stopped and the end of the test cycle shall be indicated in the recorded data;

(e)	Post-test procedures according to point 7.3.2 shall be performed.

7.8.2.4.   Validation criteria

RMC tests shall be validated using the regression analysis as described in points 7.8.3.3 and 7.8.3.5. The allowed RMC tolerances are given in the following Table 6.1. Note that the RMC tolerances are different from the NRTC tolerances of Table 6.2. When conducting testing of engines of net power greater than 560 kW the regression line tolerances of Table 6.2 and the point deletion of Table 6.3 may be used.

Table 6.1

RMC Regression line tolerances

	Speed	Torque	Power
Standard error of estimate (SEE) of y on x	maximum 1 % of rated speed	maximum 2 % of maximum engine torque	maximum 2 % of maximum engine power
Slope of the regression line, a 1	0,99 to 1,01	0,98 - 1,02	0,98 - 1,02
Coefficient of determination, r 2	minimum 0,990	minimum 0,950	minimum 0,950
y intercept of the regression line, a 0	± 1 % of rated speed	± 20 Nm or 2 % of maximum torque whichever is greater	± 4 kW or 2 % of maximum power whichever is greater

In case of running the RMC test not on a transient test bed, where the second by second speed and torque values are not available, the following validation criteria shall be used.

At each mode the requirements for the speed and torque tolerances are given in point 7.8.1.3. For the 20 s linear speed and linear torque transitions between the RMC steady-state test modes (point 7.4.1.2) the following tolerances for speed and load shall be applied for the ramp:

(a)	the speed shall be held linear within ± 2 % of rated speed,

(b)	the torque shall be held linear within ± 5 % of the maximum torque at rated speed.

7.8.3.   Transient (NRTC and LSI-NRTC) test cycles

Reference speeds and torques commands shall be sequentially executed to perform the NRTC and LSI-NRTC. Speed and torque commands shall be issued at a frequency of at least 5 Hz. Because the reference test cycle is specified at 1 Hz, the in between speed and torque commands shall be linearly interpolated from the reference torque values generated from cycle generation.

Small denormalized speed values near warm idle speed may cause low-speed idle governors to activate and the engine torque to exceed the reference torque even though the operator demand is at a minimum. In such cases, it is recommended to control the dynamometer so it gives priority to follow the reference torque instead of the reference speed and let the engine govern the speed.

Under cold-start conditions engines may use an enhanced-idle device to quickly warm up the engine and the exhaust after-treatment system. Under these conditions, very low normalized speeds will generate reference speeds below this higher enhanced idle speed. In this case it is recommended controlling the dynamometer so it gives priority to follow the reference torque and let the engine govern the speed when the operator demand is at minimum.

During an emission test, reference speeds and torques and the feedback speeds and torques shall be recorded with a minimum frequency of 1 Hz, but preferably of 5 Hz or even 10 Hz. This larger recording frequency is important as it helps to minimize the biasing effect of the time lag between the reference and the measured feedback speed and torque values.

The reference and feedback speeds and torques maybe recorded at lower frequencies (as low as 1 Hz), if the average values over the time interval between recorded values are recorded. The average values shall be calculated based on feedback values updated at a frequency of at least 5 Hz. These recorded values shall be used to calculate cycle-validation statistics and total work.

7.8.3.1.   Performing an NRTC test

Pre-test procedures according to point 7.3.1 shall be performed, including pre-conditioning, cool-down and analyzer calibration.

Testing shall be started as follows:

The test sequence shall commence immediately after the engine has started from cooled down condition specified in point 7.3.1.2 in case of the cold-start NRTC or from hot soak condition in case of the hot-start NRTC. The sequence in point 7.4.2.1 shall be followed.

Data logging, sampling of exhaust gas and integrating measured values shall be initiated simultaneously at the start of the engine. The test cycle shall be initiated when the engine starts and shall be executed according to the schedule of Appendix 3 of Annex XVII.

At the end of the cycle, sampling shall be continued, operating all systems to allow system response time to elapse. Then all sampling and recording shall be stopped, including the recording of background samples. Finally, any integrating devices shall be stopped and the end of the test cycle shall be indicated in the recorded data.

Post-test procedures according to point 7.3.2 shall be performed.

7.8.3.2.   Performing an LSI-NRTC test

Pre-test procedures according to point 7.3.1 shall be performed, including pre-conditioning and analyzer calibration.

Testing shall be started as follows:

The test shall commence according to the sequence given in point 7.4.2.2.

Data logging, sampling of exhaust gas and integrating measured values shall be initiated simultaneously with the start of the LSI-NRTC at the end of the 30-second idle period specified in point 7.4.2.2(b). The test cycle shall be executed according to the schedule of Appendix 3 of Annex XVII.

At the end of the cycle, sampling shall be continued, operating all systems to allow system response time to elapse. Then all sampling and recording shall be stopped, including the recording of background samples. Finally, any integrating devices shall be stopped and the end of the test cycle shall be indicated in the recorded data.

Post-test procedures according to point 7.3.2 shall be performed.

7.8.3.3.   Cycle validation criteria for transient (NRTC and LSI-NRTC) test cycles

In order to check the validity of a test, the cycle-validation criteria in this point shall be applied to the reference and feedback values of speed, torque, power and overall work.

7.8.3.4.   Calculation of cycle work

Before calculating the cycle work, any speed and torque values recorded during engine starting shall be omitted. Points with negative torque values have to be accounted for as zero work. The actual cycle work W act (kWh) shall be calculated based on engine feedback speed and torque values. The reference cycle work W ref (kWh) shall be calculated based on engine reference speed and torque values. The actual cycle work W act is used for comparison to the reference cycle work W ref and for calculating the brake specific emissions (see point 7.2).

W act shall be between 85 % and 105 % of W ref.

7.8.3.5.   Validation statistics (see Appendix 2 of Annex VII)

Linear regression between the reference and the feedback values shall be calculated for speed, torque and power.

To minimize the biasing effect of the time lag between the reference and feedback cycle values, the entire engine speed and torque feedback signal sequence may be advanced or delayed in time with respect to the reference speed and torque sequence. If the feedback signals are shifted, both speed and torque shall be shifted by the same amount in the same direction.

The method of least squares shall be used, with the best-fit equation having the form set out in equation (6-19):

y= a 1 x + a 0

(6-19)

where:

y	is the feedback value of speed (min– 1), torque (Nm), or power (kW)
a 1	is the slope of the regression line
x	is the reference value of speed (min– 1), torque (Nm), or power (kW)
a 0	is the y intercept of the regression line.

The standard error of estimate (SEE) of y on x and the coefficient of determination (r 2) shall be calculated for each regression line in accordance with Appendix 3 of Annex VII.

It is recommended that this analysis be performed at 1 Hz. For a test to be considered valid, the criteria of Table 6.2 shall be met.

Table 6.2

Regression line tolerances

	Speed	Torque	Power
Standard error of estimate (SEE) of y on x	≤ 5,0 percent of maximum test speed	≤ 10,0 % of maximum mapped torque	≤ 10,0 % of maximum mapped power
Slope of the regression line, a 1	0,95 to 1,03	0,83 - 1,03	0,89 - 1,03
Coefficient of determination, r 2	minimum 0,970	minimum 0,850	minimum 0,910
y intercept of the regression line, a 0	≤ 10 % of idle	± 20 Nm or ± 2 % of maximum torque whichever is greater	± 4 kW or ± 2 % of maximum power whichever is greater

For regression purposes only, point deletions are permitted where noted in Table 6.3 before doing the regression calculation. However, those points shall not be deleted for the calculation of cycle work and emissions. An idle point is defined as a point having a normalized reference torque of 0 % and a normalized reference speed of 0 %. Point deletion may be applied to the whole or to any part of the cycle; points to which the point deletion is applied have to be specified.

Table 6.3

Permitted point deletions from regression analysis

Event	Conditions (n = engine speed, T = torque)	Permitted point deletions
Minimum operator demand (idle point)	n ref = n idle and T ref = 0 % and T act > (T ref – 0,02 T maxmappedtorque) and T act < (T ref + 0,02 T maxmappedtorque)	speed and power
Minimum operator demand	n act ≤ 1,02 n ref and T act > T ref or n act > n ref and T act ≤ T ref' or n act > 1,02 n ref and T ref < T act ≤ (T ref + 0,02 T maxmappedtorque)	power and either torque or speed
Maximum operator demand	n act < n ref and T act ≥ T ref or n act ≥ 0,98 n ref and T act < T ref or n act < 0,98 n ref and T ref > T act ≥ (T ref – 0,02 T maxmappedtorque)	power and either torque or speed

8.   Measurement procedures

8.1.   Calibration and performance checks

8.1.1.   Introduction

This point describes required calibrations and verifications of measurement systems. See point 9.4 for specifications that apply to individual instruments.

Calibrations or verifications shall be generally performed over the complete measurement chain.

If a calibration or verification for a portion of a measurement system is not specified, that portion of the system shall be calibrated and its performance verified at a frequency consistent with any recommendations from the measurement system manufacturer and consistent with good engineering judgment.

Internationally recognized-traceable standards shall be used to meet the tolerances specified for calibrations and verifications.

8.1.2.   Summary of calibration and verification

Table 6.4 summarizes the calibrations and verifications described in section 8 and indicates when these have to be performed.

Table 6.4

Summary of Calibration and Verifications

Type of calibration or verification	Minimum frequency (1)
8.1.3: accuracy, repeatability and noise	Accuracy: Not required, but recommended for initial installation. Repeatability: Not required, but recommended for initial installation. Noise: Not required, but recommended for initial installation.
8.1.4: linearity verification	Speed: Upon initial installation, within 370 days before testing and after major maintenance. Torque: Upon initial installation, within 370 days before testing and after major maintenance. Intake air, dilution air and diluted exhaust gas flows and batch sample flow rates: Upon initial installation, within 370 days before testing and after major maintenance, unless flow is verified by propane check or by carbon or oxygen balance. Raw exhaust gas flow: Upon initial installation, within 185 days before testing and after major maintenance, unless flow is verified by propane check or by carbon or oxygen balance. Gas dividers: Upon initial installation, within 370 days before testing and after major maintenance. Gas analyzers (unless otherwise noted): Upon initial installation, within 35 days before testing and after major maintenance. FTIR analyser: Upon installation, within 370 days before testing and after major maintenance. PM balance: Upon initial installation, within 370 days before testing and after major maintenance. Stand-alone pressure and temperature: Upon initial installation, within 370 days before testing and after major maintenance.
8.1.5: Continuous gas analyzer system response and updating-recording verification — for gas analyzers not continuously compensated for other gas species	Upon initial installation or after system modification that would affect response.
8.1.6: Continuous gas analyzer system response and updating-recording verification — for gas analyzers continuously compensated for other gas species	Upon initial installation or after system modification that would affect response.
8.1.7.1: torque	Upon initial installation and after major maintenance.
8.1.7.2: pressure, temperature, dew point	Upon initial installation and after major maintenance.
8.1.8.1: fuel flow	Upon initial installation and after major maintenance.
8.1.8.2: intake flow	Upon initial installation and after major maintenance.
8.1.8.3: exhaust gas flow	Upon initial installation and after major maintenance.
8.1.8.4: diluted exhaust gas flow (CVS and PFD)	Upon initial installation and after major maintenance.
8.1.8.5: CVS/PFD and batch sampler verification (2)	Upon initial installation, within 35 days before testing, and after major maintenance. (Propane check)
8.1.8.8: vacuum leak	Upon installation of the sampling system. Before each laboratory test according to point 7.1: within 8 hours before the start of the first test interval of each duty cycle sequence and after maintenance such as pre-filter changes.
8.1.9.1: CO2 NDIR H2O interference	Upon initial installation and after major maintenance.
8.1.9.2: CO NDIR CO2 and H2O interference	Upon initial installation and after major maintenance.
8.1.10.1: FID calibration HC FID optimization and HC FID verification	Calibrate, optimize, and determine CH4 response: upon initial installation and after major maintenance. Verify CH4 response: upon initial installation, within 185 days before testing, and after major maintenance.
8.1.10.2: raw exhaust gas FID O2 interference	For all FID analyzers: upon initial installation, and after major maintenance. For THC FID analyzers: upon initial installation, after major maintenance, and after FID optimization according to 8.1.10.1.
8.1.11.1: CLD CO2 and H2O quench	Upon initial installation and after major maintenance.
8.1.11.3: NDUV HC and H2O interference	Upon initial installation and after major maintenance.
8.1.11.4: cooling bath NO2 penetration (chiller)	Upon initial installation and after major maintenance.
8.1.11.5: NO2-to-NO converter conversion	Upon initial installation, within 35 days before testing, and after major maintenance.
8.1.12.1: Sample dryer verification	For thermal chillers: upon installation and after major maintenance. For osmotic membranes: upon installation, within 35 days of testing and after major maintenance
8.1.13.1: PM balance and weighing	Independent verification: upon initial installation, within 370 days before testing, and after major maintenance. Zero, span, and reference sample verifications: within 12 hours of weighing, and after major maintenance.

8.1.3.   Verifications for accuracy, repeatability, and noise

The performance values for individual instruments specified in Table 6.8 are the basis for the determination of the accuracy, repeatability, and noise of an instrument.

It is not required to verify instrument accuracy, repeatability, or noise. However, it may be useful to consider these verifications to define a specification for a new instrument, to verify the performance of a new instrument upon delivery, or to troubleshoot an existing instrument.

8.1.4.   Linearity verification

8.1.4.1.   Scope and frequency

A linearity verification shall be performed on each measurement system listed in Table 6.5 at least as frequently as indicated in the Table, consistent with measurement system manufacturer recommendations and good engineering judgment. The intent of a linearity verification is to determine that a measurement system responds proportionally over the measurement range of interest. A linearity verification shall consist of introducing a series of at least 10 reference values to a measurement system, unless otherwise specified. The measurement system quantifies each reference value. The measured values shall be collectively compared to the reference values by using a least squares linear regression and the linearity criteria specified in Table 6.5.

8.1.4.2.   Performance requirements

If a measurement system does not meet the applicable linearity criteria in Table 6.5, the deficiency shall be corrected by re-calibrating, servicing, or replacing components as needed. The linearity verification shall be repeated after correcting the deficiency to ensure that the measurement system meets the linearity criteria.

8.1.4.3.   Procedure

The following linearity verification protocol shall be used:

(a)	A measurement system shall be operated at its specified temperatures, pressures, and flows;

(b)	The instrument shall be zeroed as it would before an emission test by introducing a zero signal. For gas analyzers, a zero gas shall be used that meets the specifications of point 9.5.1 and it shall be introduced directly at the analyzer port;

(c)	The instrument shall be spanned as it would before an emission test by introducing a span signal. For gas analyzers, a span gas shall be used that meets the specifications of point 9.5.1 and it shall be introduced directly at the analyzer port;

(d)	After spanning the instrument, zero shall be checked with the same signal which has been used in paragraph (b) of this point. Based on the zero reading, good engineering judgment shall be used to determine whether or not to re-zero and or re-span the instrument before proceeding to the next step;

(e)

For all measured quantities manufacturer recommendations and good engineering judgment shall be used to select the reference values, y ref i , that cover the full range of values that are expected during emission testing, thus avoiding the need of extrapolation beyond these values. A zero reference signal shall be selected as one of the reference values of the linearity verification. For stand-alone pressure and temperature linearity verifications, at least three reference values shall be selected. For all other linearity verifications, at least ten reference values shall be selected;

(f)	Instrument manufacturer recommendations and good engineering judgment shall be used to select the order in which the series of reference values will be introduced;

(g)	Reference quantities shall be generated and introduced as described in point 8.1.4.4. For gas analyzers, gas concentrations known to be within the specifications of point 9.5.1 shall be used and they shall be introduced directly at the analyzer port;

(h)	Time for the instrument to stabilize while it measures the reference value shall be allowed;

(i)	At a recording frequency of at least the minimum frequency, as specified in Table 6.7, the reference value shall be measured for 30 s and the arithmetic mean of the recorded values, recorded;

(j)	Steps in paragraphs (g) to (i) of this point shall be repeated until all reference quantities are measured;

(k)	The arithmetic means , and reference values, y ref i , shall be used to calculate least-squares linear regression parameters and statistical values to compare to the minimum performance criteria specified in Table 6.5. The calculations described in Appendix 3 of Annex VII shall be used.

8.1.4.4.   Reference signals

This point describes recommended methods for generating reference values for the linearity-verification protocol in point 8.1.4.3. Reference values shall be used that simulate actual values, or an actual value shall be introduced and measured with a reference-measurement system. In the latter case, the reference value is the value reported by the reference-measurement system. Reference values and reference-measurement systems shall be internationally traceable.

For temperature measurement systems with sensors like thermocouples, RTDs, and thermistors, the linearity verification may be performed by removing the sensor from the system and using a simulator in its place. A simulator that is independently calibrated and cold junction compensated, as necessary shall be used. The internationally traceable simulator uncertainty scaled to temperature shall be less than 0,5 % of maximum operating temperature T max. If this option is used, it is necessary to use sensors that the supplier states are accurate to better than 0,5 % of T max compared to their standard calibration curve.

8.1.4.5.   Measurement systems that require linearity verification

Table 6.5 indicates measurement systems that require linearity verifications. For this Table the following provisions shall apply:

(a)	a linearity verification shall be performed more frequently if the instrument manufacturer recommends it or based on good engineering judgment;

(b)	‘min’ refers to the minimum reference value used during the linearity verification; Note that this value may be zero or a negative value depending on the signal;

(c)

‘max’ generally refers to the maximum reference value used during the linearity verification. For example for gas dividers, x max is the undivided, undiluted, span gas concentration. The following are special cases where ‘max’ refers to a different value: (i) For PM balance linearity verification, m max refers to the typical mass of a PM filter; (ii) For torque linearity verification, T max refers to the manufacturer's specified engine torque peak value of the highest torque engine to be tested;

(d)	the specified ranges are inclusive. For example, a specified range of 0,98-1,02 for the slope a 1 means 0,98 ≤ a 1 ≤ 1,02;

(e)

these linearity verifications are not required for systems that pass the flow-rate verification for diluted exhaust gas as described in point 8.1.8.5 for the propane check or for systems that agree within ± 2 % based on a chemical balance of carbon or oxygen of the intake air, fuel, and exhaust gas;

(f)	a 1 criteria for these quantities shall be met only if the absolute value of the quantity is required, as opposed to a signal that is only linearly proportional to the actual value;

(g)

stand-alone temperatures include engine temperatures and ambient conditions used to set or verify engine conditions; temperatures used to set or verify critical conditions in the test system; and temperatures used in emissions calculations: (i) these temperature linearity checks are required. Air intake; after-treatment bed(s) (for engines tested with exhaust after-treatment systems on cycles with cold start criteria); dilution air for PM sampling (CVS, double dilution, and partial flow systems); PM sample; and chiller sample (for gaseous sampling systems that use chillers to dry samples); (ii) these temperature linearity checks are only required if specified by the engine manufacturer. Fuel inlet; test cell charge air cooler air outlet (for engines tested with a test cell heat exchanger simulating a non-road mobile machinery charge air cooler); test cell charge air cooler coolant inlet (for engines tested with a test cell heat exchanger simulating a non-road mobile machinery charge air cooler); and oil in the sump/pan; coolant before the thermostat (for liquid cooled engines);

(h)

stand-alone pressures include engine pressures and ambient conditions used to set or verify engine conditions; pressures used to set or verify critical conditions in the test system; and pressures used in emissions calculations: (i) required pressure linearity checks are: intake air pressure restriction; exhaust gas back-pressure; barometer; CVS inlet gage pressure (if measurement using CVS); chiller sample (for gaseous sampling systems that use chillers to dry samples); (ii) pressure linearity checks that are required only if specified by the engine manufacturer: test cell charge air cooler and interconnecting pipe pressure drop (for turbo-charged engines tested with a test cell heat exchanger simulating a non-road mobile machinery charge air cooler) fuel inlet; and fuel outlet.

Table 6.5

Measurement systems that require linearity verifications

Measurement System	Quantity	Minimum verification frequency	Linearity Criteria
				α	SEE	r 2
Engine speed	n	Within 370 days before testing	≤ 0,05 % n max	0,98-1,02	≤ 2 % n max	≥ 0,990
Engine torque	T	Within 370 days before testing	≤ 1 % T max	0,98-1,02	≤ 2 % T max	≥ 0,990
Fuel flow rate	qm	Within 370 days before testing	≤ 1 % qm , max	0,98-1,02	≤ 2 % qm , max	≥ 0,990
Intake-air flow rate (1)	qV	Within 370 days before testing	≤ 1 % qV , max	0,98-1,02	≤ 2 % qV , max	≥ 0,990
Dilution air flow rate (1)	qV	Within 370 days before testing	≤ 1 % qV , max	0,98-1,02	≤ 2 % qV , max	≥ 0,990
Diluted exhaust gas flow rate (1)	qV	Within 370 days before testing	≤ 1 % qV , max	0,98-1,02	≤ 2 % qV , max	≥ 0,990
Raw exhaust gas flow rate (1)	qV	Within 185 days before testing	≤ 1 % qV , max	0,98-1,02	≤ 2 % qV , max	≥ 0,990
Batch sampler flow rates (1)	qV	Within 370 days before testing	≤ 1 % qV , max	0,98-1,02	≤ 2 % qV , max	≥ 0,990
Gas dividers	x/x span	Within 370 days before testing	≤ 0,5 % x max	0,98-1,02	≤ 2 % x max	≥ 0,990
Gas analyzers	x	Within 35 days before testing	≤ 0,5 % x max	0,99-1,01	≤ 1 % x max	≥ 0,998
PM balance	m	Within 370 days before testing	≤ 1 % m max	0,99-1,01	≤ 1 % m max	≥ 0,998
Stand-alone pressures	p	Within 370 days before testing	≤ 1 % p max	0,99-1,01	≤ 1 % p max	≥ 0,998
Analog-to-digital conversion of stand-alone temperature signals	T	Within 370 days before testing	≤ 1 % T max	0,99-1,01	≤ 1 % T max	≥ 0,998

8.1.5.   Continuous gas analyser system-response and updating-recording verification

This section describes a general verification procedure for continuous gas analyzer system response and update recording. See point 8.1.6 for verification procedures for compensation type analysers.

8.1.5.1.   Scope and frequency

This verification shall be performed after installing or replacing a gas analyzer that is used for continuous sampling. Also this verification shall be performed if the system is reconfigured in a way that would change system response. This verification is needed for continuous gas analysers used for transient (NRTC and LSI-NRTC) test cycles or RMC but is not needed for batch gas analyzer systems or for continuous gas analyzer systems used only for testing with a discrete-mode NRSC.

8.1.5.2.   Measurement principles

This test verifies that the updating and recording frequencies match the overall system response to a rapid change in the value of concentrations at the sample probe. Gas analyzer systems shall be optimized such that their overall response to a rapid change in concentration is updated and recorded at an appropriate frequency to prevent loss of information. This test also verifies that continuous gas analyzer systems meet a minimum response time.

The system settings for the response time evaluation shall be exactly the same as during measurement of the test run (i.e. pressure, flow rates, filter settings on the analyzers and all other response time influences). The response time determination shall be done with gas switching directly at the inlet of the sample probe. The devices for gas switching shall have a specification to perform the switching in less than 0,1 s. The gases used for the test shall cause a concentration change of at least 60 % full scale (FS).

The concentration trace of each single gas component shall be recorded.

8.1.5.3.   System requirements

(a)	The system response time shall be ≤ 10 s with a rise time of ≤ 5 s for all measured components (CO, NOx, 2 and HC) and all ranges used. All data (concentration, fuel and air flows) have to be shifted by their measured response times before performing the emission calculations given in Annex VII.

(b)

To demonstrate acceptable updating and recording with respect to the system's overall response, the system shall meet one of the following criteria: (i) The product of the mean rise time and the frequency at which the system records an updated concentration shall be at least 5. In any case the mean rise time shall be no more than 10 s; (ii) The frequency at which the system records the concentration shall be at least 2 Hz (see also Table 6.7).

8.1.5.4.   Procedure

The following procedure shall be used to verify the response of each continuous gas analyzer system:

(a)

The analyzer system manufacturer's start-up and operating instructions for the instrument setup shall be followed. The measurement system shall be adjusted as needed to optimize performance. This verification shall be run with the analyzer operating in the same manner as used for emission testing. If the analyzer shares its sampling system with other analyzers, and if gas flow to the other analyzers will affect the system response time, then the other analyzers shall be started up and operated while running this verification test. This verification test may be run on multiple analyzers sharing the same sampling system at the same time. If analogue or real-time digital filters are used during emission testing, those filters shall be operated in the same manner during this verification;

(b)

For equipment used to validate system response time, minimal gas transfer line lengths between all connections are recommended to be used, a zero-air source shall be connected to one inlet of a fast-acting 3-way valve (2 inlets, 1 outlet) in order to control the flow of zero and blended span gases to the sample system's probe inlet or a tee near the outlet of the probe. Normally the gas flow rate is higher than the probe sample flow rate and the excess is overflowed out the inlet of the probe. If the gas flow rate is lower than the probe flow rate, the gas concentrations shall be adjusted to account for the dilution from ambient air drawn into the probe. Binary or multi-gas span gases may be used. A gas blending or mixing device may be used to blend span gases. A gas blending or mixing device is recommended when blending span gases diluted in N2 with span gases diluted in air; Using a gas divider, an NO–CO–CO2–C3H8–CH4 (balance N2) span gas shall be equally blended with a span gas of NO2, balance purified synthetic air. Standard binary span gases may be also be used, where applicable, in place of blended NO-CO-CO2-C3H8-CH4, balance N2 span gas; in this case separate response tests shall be run for each analyzer. The gas divider outlet shall be connected to the other inlet of the 3-way valve. The valve outlet shall be connected to an overflow at the gas analyzer system's probe or to an overflow fitting between the probe and transfer line to all the analyzers being verified. A setup that avoids pressure pulsations due to stopping the flow through the gas blending device shall be used. Any of these gas constituents if they are not relevant to the analyzers for this verification shall be omitted. Alternatively the use of gas bottles with single gases and a separate measurement of response times is allowed;

(c)

Data collection shall be done as follows: (i) The valve shall be switched to start the flow of zero gas; (ii) Stabilization shall be allowed for, accounting for transport delays and the slowest analyzer's full response; (iii) Data recording shall be started at the frequency used during emission testing. Each recorded value shall be a unique updated concentration measured by the analyzer; interpolation or filtering may not be used to alter recorded values; (iv) The valve shall be switched to allow the blended span gases to flow to the analyzers. This time shall be recorded as t 0; (v) Transport delays and the slowest analyzer's full response shall be allowed for; (vi) The flow shall be switched to allow zero gas to flow to the analyzer. This time shall be recorded as t 100; (vii) Transport delays and the slowest analyzer's full response shall be allowed for; (viii) The steps in paragraphs (c)(iv) to (vii) of this point shall be repeated to record seven full cycles, ending with zero gas flowing to the analyzers; (ix) Recording shall be stopped.

8.1.5.5.   Performance evaluation

The data from point 8.1.5.4(c) shall be used to calculate the mean rise time for each of the analyzers.

(a)

If it is chosen to demonstrate compliance with point 8.1.5.3(b)(i) the following procedure has to be applied: The rise times (in s) shall be multiplied by their respective recording frequencies in Hertz (1/s). The value for each result shall be at least 5. If the value is less than 5, the recording frequency shall be increased or the flows adjusted or the design of the sampling system shall be changed to increase the rise time as needed. Also digital filters may be configured to increase rise time;

(b)	If it is chosen to demonstrate compliance with point 8.1.5.3(b)(ii), the demonstration of compliance with the requirements of point 8.1.5.3(b)(ii) is sufficient.

8.1.6.   Response time verification for compensation type analysers

8.1.6.1.   Scope and frequency

This verification shall be performed to determine a continuous gas analyzer's response, where one analyzer's response is compensated by another's to quantify a gaseous emission. For this check water vapour shall be considered to be a gaseous constituent. This verification is required for continuous gas analyzers used for transient (NRTC and LSI-NRTC) test cycles or RMC. This verification is not needed for batch gas analyzers or for continuous gas analyzers that are used only for testing with a discrete-mode NRSC. This verification does not apply to correction for water removed from the sample done in post-processing. This verification shall be performed after initial installation (i.e. test cell commissioning). After major maintenance, point 8.1.5 may be used to verify uniform response provided that any replaced components have gone through a humidified uniform response verification at some point.

8.1.6.2.   Measurement principles

This procedure verifies the time-alignment and uniform response of continuously combined gas measurements. For this procedure, it is necessary to ensure that all compensation algorithms and humidity corrections are turned on.

8.1.6.3.   System requirements

The general response time and rise time requirement set out in point 8.1.5.3(a) is also valid for compensation type analysers. Additionally, if the recording frequency is different than the update frequency of the continuously combined/compensated signal, the lower of these two frequencies shall be used for the verification required by point 8.1.5.3(b)(i).

8.1.6.4.   Procedure

All procedures set out in point 8.1.5.4(a) to (c) shall be used. Additionally also the response and rise time of water vapour has to be measured, if a compensation algorithm based on measured water vapour is used. In this case at least one of the used calibration gases (but not NO2) has to be humidified as follows:

If the system does not use a sample dryer to remove water from the sample gas, the span gas shall be humidified by flowing the gas mixture through a sealed vessel that humidifies the gas to the highest sample dew point that is estimated during emission sampling by bubbling it through distilled water. If the system uses a sample dryer during testing that has passed the sample dryer verification check, the humidified gas mixture may be introduced downstream of the sample dryer by bubbling it through distilled water in a sealed vessel at 298 ± 10 K (25 ± 10 °C), or a temperature greater than the dew point. In all cases, downstream of the vessel, the humidified gas shall be maintained at a temperature of at least 5 K (5 °C) above its local dew point in the line. Note that it is possible to omit any of these gas constituents if they are not relevant to the analyzers for this verification. If any of the gas constituents are not susceptible to water compensation, the response check for these analyzers may be performed without humidification.

8.1.7.   Measurement of engine parameters and ambient conditions

The engine manufacturer shall apply internal quality procedures traceable to recognised national or international standards. Otherwise the following procedures apply.

8.1.7.1.   Torque calibration

8.1.7.1.1.   Scope and frequency

All torque-measurement systems including dynamometer torque measurement transducers and systems shall be calibrated upon initial installation and after major maintenance using, among others, reference force or lever-arm length coupled with dead weight. Good engineering judgment shall be used to repeat the calibration. The torque transducer manufacturer's instructions shall be followed for linearizing the torque sensor's output. Other calibration methods are permitted.

8.1.7.1.2.   Dead-weight calibration

This technique applies a known force by hanging known weights at a known distance along a lever arm. It shall be made sure that the weights' lever arm is perpendicular to gravity (i.e., horizontal) and perpendicular to the dynamometer's rotational axis. At least six calibration-weight combinations shall be applied for each applicable torque-measuring range, spacing the weight quantities about equally over the range. The dynamometer shall be oscillated or rotated during calibration to reduce frictional static hysteresis. Each weight's force shall be determined by multiplying its internationally-traceable mass by the local acceleration of Earth's gravity.

8.1.7.1.3.   Strain gage or proving ring calibration

This technique applies force either by hanging weights on a lever arm (these weights and their lever arm length are not used as part of the reference torque determination) or by operating the dynamometer at different torques. At least six force combinations shall be applied for each applicable torque-measuring range, spacing the force quantities about equally over the range. The dynamometer shall be oscillated or rotated during calibration to reduce frictional static hysteresis. In this case, the reference torque is determined by multiplying the force output from the reference meter (such as a strain gage or proving ring) by its effective lever-arm length, which is measured from the point where the force measurement is made to the dynamometer's rotational axis. It shall be made sure that this length is measured perpendicular to the reference meter's measurement axis and perpendicular to the dynamometer's rotational axis.

8.1.7.2.   Pressure, temperature, and dew point calibration

Instruments shall be calibrated for measuring pressure, temperature, and dew point upon initial installation. The instrument manufacturer's instructions shall be followed and good engineering judgment shall be used to repeat the calibration.

For temperature measurement systems with thermocouple, RTD, or thermistor sensors, the calibration of the system shall be performed as described in point 8.1.4.4 for linearity verification.

8.1.8.   Flow-related measurements

8.1.8.1.   Fuel flow calibration

Fuel flow meters shall be calibrated upon initial installation. The instrument manufacturer's instructions shall be followed and good engineering judgment shall be used to repeat the calibration.

8.1.8.2.   Intake air flow calibration

Intake air flow meters shall be calibrated upon initial installation. The instrument manufacturer's instructions shall be followed and good engineering judgment shall be used to repeat the calibration.

8.1.8.3.   Exhaust gas flow calibration

Exhaust flow meters shall be calibrated upon initial installation. The instrument manufacturer's instructions shall be followed and good engineering judgment shall be used to repeat the calibration.

8.1.8.4.   Diluted exhaust gas flow (CVS) calibration

8.1.8.4.1.   Overview

(a)	This section describes how to calibrate flow meters for diluted exhaust gas constant-volume sampling (CVS) systems;

(b)

This calibration shall be performed while the flow meter is installed in its permanent position. This calibration shall be performed after any part of the flow configuration upstream or downstream of the flow meter has been changed that may affect the flow-meter calibration. This calibration shall be performed upon initial CVS installation and whenever corrective action does not resolve a failure to meet the diluted exhaust gas flow verification (i.e., propane check) in point 8.1.8.5;

(c)

A CVS flow meter shall be calibrated using a reference flow meter such as a subsonic venturi flow meter, a long-radius flow nozzle, a smooth approach orifice, a laminar flow element, a set of critical flow venturis, or an ultrasonic flow meter. A reference flow meter shall be used that reports quantities that are internationally-traceable within ± 1 % uncertainty. This reference flow meter's response to flow shall be used as the reference value for CVS flow-meter calibration;

(d)	An upstream screen or other pressure restriction that could affect the flow ahead of the reference flow meter may not be used, unless the flow meter has been calibrated with such a pressure restriction;

(e)	The calibration sequence described under this point 8.1.8.4 refers to the molar based approach. For the corresponding sequence used in the mass based approach, see point 2.5 of Annex VII.

(f)

By the choice of the manufacturer, CFV or SSV may alternatively be removed from its permanent position for calibration as long as the following requirements are met when installed in the CVS: (1) Upon installation of the CFV or SSV into the CVS, good engineering judgment shall be applied to verify that any leaks have not been introduced between the CVS inlet and the venturi. (2) After ex-situ venturi calibration, all venturi flow combinations must be verified for CFVs or at minimum of 10 flow points for an SSV using the propane check as described in point 8.1.8.5. The result of the propane check for each venturi flow point may not exceed the tolerance in point 8.1.8.5.6. (3) In order to verify the ex-situ calibration for a CVS with more than a single CFV, the following verification shall be conducted: (i) A constant flow device shall be used to deliver a constant flow of propane to the dilution tunnel. (ii) The hydrocarbon concentrations shall be measured at a minimum of 10 separate flow rates for an SSV flow meter, or at all possible flow combinations for a CFV flow meter, while keeping the flow of propane constant. (iii) The concentration of hydrocarbon background in the dilution air shall be measured at the beginning and end of this test. The average background concentration from each measurement at each flow point must be subtracted before performing the regression analysis in paragraph (iv). (iv) A power regression has to be performed using all the paired values of flow rate and corrected concentration to obtain a relationship in the form of y = a × xb, using the concentration as the independent variable and the flow rate as the dependent variable. For each data point, the calculation of the difference between the measured flow rate and the value represented by the curve fit is required. The difference at each point must be less than ± 1 % of the appropriate regression value. The value of b must be between – 1,005 and – 0,995. If the results do not meet these limits, corrective actions consistent with point 8.1.8.5.1(a) must be taken.

8.1.8.4.2.   PDP calibration

A positive-displacement pump (PDP) shall be calibrated to determine a flow-versus-PDP speed equation that accounts for flow leakage across sealing surfaces in the PDP as a function of PDP inlet pressure. Unique equation coefficients shall be determined for each speed at which the PDP is operated. A PDP flow meter shall be calibrated as follows:

(a)	The system shall be connected as shown in Figure 6.5;

(b)	Leaks between the calibration flow meter and the PDP shall be less than 0,3 % of the total flow at the lowest calibrated flow point; for example, at the highest pressure restriction and lowest PDP-speed point;

(c)	While the PDP operates, a constant temperature at the PDP inlet shall be maintained within ± 2 % of the mean absolute inlet temperature, T in;

(d)	The PDP speed is set to the first speed point at which it is intended to calibrate;

(e)	The variable restrictor is set to its wide-open position;

(f)

The PDP is operated for at least 3 minutes to stabilize the system. Then by continuously operating the PDP, the mean values of at least 30 s of sampled data of each of the following quantities are recorded: (i) The mean flow rate of the reference flow meter, ; (ii) The mean temperature at the PDP inlet, T in; (iii) The mean static absolute pressure at the PDP inlet, p in; (iv) The mean static absolute pressure at the PDP outlet, p out; (v) The mean PDP speed, n PDP;

(g)	The restrictor valve shall be incrementally closed to decrease the absolute pressure at the inlet to the PDP, p in;

(h)	The steps in paragraphs 8.1.8.4.2(f) and (g) shall be repeated to record data at a minimum of six restrictor positions reflecting the full range of possible in-use pressures at the PDP inlet;

(i)	The PDP shall be calibrated by using the collected data and the equations set out in Annex VII;

(j)	The steps in paragraphs (f) to (i) of this point shall be repeated for each speed at which the PDP is operated;

(k)	The equations in section 3 of Annex VII (molar based approach) or section 2 of Annex VII (mass based approach) shall be used to determine the PDP flow equation for emission testing;

(l)	The calibration shall be verified by performing a CVS verification (i.e., propane check) as described in point 8.1.8.5;

(m)	The PDP may not be used below the lowest inlet pressure tested during calibration.

8.1.8.4.3.   CFV calibration

A critical-flow venturi (CFV) shall be calibrated to verify its discharge coefficient, C d, at the lowest expected static differential pressure between the CFV inlet and outlet. A CFV flow meter shall be calibrated as follows:

(a)	The system shall be connected as shown in Figure 6.5;

(b)	The blower shall be started downstream of the CFV;

(c)	While the CFV operates, a constant temperature at the CFV inlet shall be maintained within ± 2 % of the mean absolute inlet temperature, T in;

(d)	Leaks between the calibration flow meter and the CFV shall be less than 0,3 % of the total flow at the highest pressure restriction;

(e)	The variable restrictor shall be set to its wide-open position. In lieu of a variable restrictor the pressure downstream of the CFV may be varied by varying blower speed or by introducing a controlled leak. Note that some blowers have limitations on non-loaded conditions;

(f)

The CFV shall be operated for at least 3 minutes to stabilize the system. The CFV shall continue operating and the mean values of at least 30 s of sampled data of each of the following quantities shall be recorded: (i) The mean flow rate of the reference flow meter, ; (ii) Optionally, the mean dew point of the calibration air, T dew. See Annex VII for permissible assumptions during emission measurements; (iii) The mean temperature at the venturi inlet, T in; (iv) The mean static absolute pressure at the venturi inlet, p in; (v) The mean static differential pressure between the CFV inlet and the CFV outlet, Δp CFV;

(g)	The restrictor valve shall be incrementally closed to decrease the absolute pressure at the inlet to the CFV, p in;

(h)

The steps in paragraphs (f) and (g) of this point shall be repeated to record mean data at a minimum of ten restrictor positions, such that the fullest practical range of Δp CFV expected during testing is tested. It is not required to remove calibration components or CVS components to calibrate at the lowest possible pressure restrictions;

(i)	Cd and the highest allowable pressure ratio r shall be determined as described in Annex VII;

(j)	Cd shall be used to determine CFV flow during an emission test. The CFV shall not be used above the highest allowed r, as determined in Annex VII;

(k)	The calibration shall be verified by performing a CVS verification (i.e., propane check) as described in point 8.1.z8.5;

(l)

If the CVS is configured to operate more than one CFV at a time in parallel, the CVS shall be calibrated by one of the following: (i) Every combination of CFVs shall be calibrated according to this section and with Annex VII. See Annex VII for instructions on calculating flow rates for this option; (ii) Each CFV shall be calibrated according to this point and Annex VII. See Annex VII for instructions on calculating flow rates for this option.

8.1.8.4.4.   SSV calibration

A subsonic venturi (SSV) shall be calibrated to determine its calibration coefficient, C d, for the expected range of inlet pressures. An SSV flow meter shall be calibrated as follows:

(a)	The system shall be connected as shown in Figure 6.5;

(b)	The blower shall be started downstream of the SSV;

(c)	Leaks between the calibration flow meter and the SSV shall be less than 0,3 % of the total flow at the highest pressure restriction;

(d)	While the SSV operates, a constant temperature at the SSV inlet shall be maintained within ± 2 % of the mean absolute inlet temperature, T in;

(e)

The variable restrictor or variable-speed blower shall be set to a flow rate greater than the greatest flow rate expected during testing. Flow rates may not be extrapolated beyond calibrated values, so it is recommended that it is made certain that a Reynolds number, Re, at the SSV throat at the greatest calibrated flow rate is greater than the maximum Re expected during testing;

(f)

The SSV shall be operated for at least 3 min to stabilize the system. The SSV shall continue operating and the mean of at least 30 s of sampled data of each of the following quantities shall be recorded: (i) The mean flow rate of the reference flow meter, ; (ii) Optionally, the mean dew point of the calibration air, T dew. See Annex VII for permissible assumptions; (iii) The mean temperature at the venturi inlet, T in; (iv) The mean static absolute pressure at the venturi inlet, p in; (v) Static differential pressure between the static pressure at the venturi inlet and the static pressure at the venturi throat, Δp SSV;

(g)	The restrictor valve shall be incrementally closed or the blower speed decreased to decrease the flow rate;

(h)	The steps in paragraphs (f) and (g) of this point shall be repeated to record data at a minimum of ten flow rates;

(i)	A functional form of C d versus Re shall be determined by using the collected data and the equations in Annex VII;

(j)	The calibration shall be verified by performing a CVS verification (i.e., propane check) as described in point 8.1.8.5 using the new C d versus Re equation;

(k)	The SSV shall be used only between the minimum and maximum calibrated flow rates;

(l)	The equations in section 3 of Annex VII (molar based approach) or section 2 of Annex VII (mass based approach) shall be used to determine SSV flow during a test.

8.1.8.4.5.   Ultrasonic calibration (reserved)

Figure 6.5

Schematic diagrams for diluted exhaust gas flow CVS calibration

8.1.8.5.   CVS and batch sampler verification (propane check)

8.1.8.5.1.   Introduction

(a)

A propane check serves as a CVS verification to determine if there is a discrepancy in measured values of diluted exhaust gas flow. A propane check also serves as a batch-sampler verification to determine if there is a discrepancy in a batch sampling system that extracts a sample from a CVS, as described in paragraph (f) of this point. Using good engineering judgment and safe practices, this check may be performed using a gas other than propane, such as CO2 or CO. A failed propane check might indicate one or more problems that may require corrective action, as follows: (i) Incorrect analyzer calibration. The FID analyzer shall be re-calibrated, repaired, or replaced; (ii) Leak checks shall be performed on CVS tunnel, connections, fasteners, and HC sampling system according to point 8.1.8.7; (iii) The verification for poor mixing shall be performed in accordance with point 9.2.2; (iv) The hydrocarbon contamination verification in the sample system shall be performed as described in point 7.3.1.2; (v) Change in CVS calibration. An in-situ calibration of the CVS flow meter shall be performed as described in point 8.1.8.4; (vi) Other problems with the CVS or sampling verification hardware or software. The CVS system, CVS verification hardware, and software shall be inspected for discrepancies;

(b)

A propane check uses either a reference mass or a reference flow rate of C3H8 as a tracer gas in a CVS. If a reference flow rate is used, any non-ideal gas behaviour of C3H8 in the reference flow meter shall be accounted for. See section 2 of Annex VII (mass based approach) or section 3 of Annex VII (molar based approach), which describe how to calibrate and use certain flow meters. No ideal gas assumption may be used in point 8.1.8.5 and Annex VII. The propane check compares the calculated mass of injected C3H8 using HC measurements and CVS flow rate measurements with the reference value.

8.1.8.5.2.   Method of introducing a known amount of propane into the CVS system

The total accuracy of the CVS sampling system and analytical system shall be determined by introducing a known mass of a pollutant gas into the system while it is being operated in the normal manner. The pollutant is analyzed, and the mass calculated in accordance with Annex VII. Either of the following two techniques shall be used:

(a)

Metering by means of a gravimetric technique shall be done as follows: A mass of a small cylinder filled with carbon monoxide or propane shall be determined with a precision of ± 0,01 g. For about 5 to 10 minutes, the CVS system shall be operated as in a normal exhaust emissions test, while carbon monoxide or propane is injected into the system. The quantity of pure gas discharged shall be determined by means of differential weighing. A gas sample shall be analyzed with the usual equipment (sampling bag or integrating method), and the mass of the gas calculated;

(b)

Metering with a critical flow orifice shall be done as follows: A known quantity of pure gas (carbon monoxide or propane) shall be fed into the CVS system through a calibrated critical orifice. If the inlet pressure is high enough, the flow rate, which is adjusted by means of the critical flow orifice, is independent of the orifice outlet pressure (critical flow). The CVS system shall be operated as in a normal exhaust emissions test for about 5 to 10 minutes. A gas sample shall be analyzed with the usual equipment (sampling bag or integrating method), and the mass of the gas calculated.

8.1.8.5.3.   Preparation of the propane check

The propane check shall be prepared as follows:

(a)	If a reference mass of C3H8 is used instead of a reference flow rate, a cylinder charged with C3H8 shall be obtained. The reference cylinder's mass of C3H8 shall be determined within ± 0,5 % of the amount of C3H8 that is expected to be used;

(b)	Appropriate flow rates shall be selected for the CVS and C3H8;

(c)	A C3H8 injection port shall be selected in the CVS. The port location shall be selected to be as close as practical to the location where engine exhaust system is introduced into the CVS. The C3H8 cylinder shall be connected to the injection system;

(d)	The CVS shall be operated and stabilized;

(e)	Any heat exchangers in the sampling system shall be pre-heated or pre-cooled;

(f)	Heated and cooled components such as sample lines, filters, chillers, and pumps shall be allowed to stabilize at operating temperature;

(g)	If applicable, a vacuum side leak verification of the HC sampling system shall be performed as described in point 8.1.8.7.

8.1.8.5.4.   Preparation of the HC sampling system for the propane check

Vacuum side leak check verification of the HC sampling system may be performed according to paragraph (g) of this point. If this procedure is used, the HC contamination procedure in point 7.3.1.2 may be used. If the vacuum side leak check is not performed according to paragraph (g), then the HC sampling system shall be zeroed, spanned, and verified for contamination, as follows:

(a)	The lowest HC analyzer range that can measure the C3H8 concentration expected for the CVS and C3H8 flow rates shall be selected;

(b)	The HC analyzer shall be zeroed using zero air introduced at the analyzer port;

(c)	The HC analyzer shall be spanned using C3H8 span gas introduced at the analyzer port;

(d)	Zero air shall be overflowed at the HC probe or into a fitting between the HC probe and the transfer line;