ANNEX

Methodology to determine the CO2 savings of efficient LED lighting by reference to the Worldwide Harmonised Light Vehicle Test Procedure

1.   INTRODUCTION

In order to determine the CO2 emission reductions that can be attributed to efficient LED lighting consisting of an appropriate combination of external vehicle LED lights for the use in internal combustion engine M1 vehicles and non-externally chargeable hybrid electrified M1 vehicles, it is necessary to establish the following:

(1)	the test conditions;

(2)	the test equipment;

(3)	the procedure to determine the power savings;

(4)	the procedure to determine the CO2 savings;

(5)	the procedure to determine the uncertainty of the CO2 savings.

2.   SYMBOLS, PARAMETERS AND UNITS

Latin symbols

AFS	—	Adaptive Front lighting System
B	—	Baseline
CO2	—	Carbon dioxide
	—	CO2 savings [g CO2/km]
C	—	Number of classes of the adaptive front lighting system
CF	—	Conversion factor (l/100 km) - (g CO2/km) [gCO2/l]
EI	—	Eco-innovative
HEV	—	Hybrid Electrified Vehicle
	—	CO2 correction factor, as defined in Regulation (EU) 2017/1151 Sub-Annex 8 Appendix 2
	—	Average of the T values of
m	—	Number of efficient exterior LED lights composing the package
MT	—	Minimum threshold [g CO2/km]
n	—	Number of measurements of the sample
NOVC	—	Not Off-Vehicle Charging
P	—	Power consumption of the vehicle light [W]
	—	Power consumption of the corresponding i light in a baseline vehicle [W]
	—	Power consumption of the corresponding n sample for each class vehicle [W]
	—	Power consumption for each class of vehicle (average of the n measurements) [W]
	—	Power consumption of the Low beam AFS [W]
	—	Average power consumption of the corresponding eco-innovative vehicle light [W]
ΔPi	—	Power savings of each efficient exterior LED light [W]
	—	Standard deviation of the total CO2 savings [g CO2/km]
	—	Standard deviation of the
	—	Standard deviation of average of the T values of
	—	Standard deviation of average of power consumption for each class of vehicle [W]
	—	Standard deviation of the LED light power consumption in eco-innovative vehicle [W]
	—	Standard deviation of the average LED light power consumption mean in eco-innovative vehicle [W]
	—	Uncertainty or Standard deviation of average of power of the Low beam AFS [W]
T	—	Number of measurements performed by the manufacturer for the extrapolation of the
t	—	Driving duration of the Worldwide Light vehicles Test Cycle (WLTC) [s], which is 1 800 s
UF	—	Usage factor for the vehicle light [-] as defined in Table 6
v	—	Mean driving speed of the Worldwide Light vehicles Test Cycle (WLTC) [km/h]
VPe	—	Consumption of effective power [l/kWh]
share c	—	Time percentage per speed band in each vehicle class
	—	Sensitivity of calculated CO2 savings related to the LED light power consumption
	—	Sensitivity of calculated CO2 savings related to the CO2 correction factor
ηA	—	Efficiency of the alternator [-]
ηDCDC	—	Efficiency of the DC-DC converter [-]

Subscripts

Index (c) refers to number of class of the adaptive front lighting system measurement of the sample

Index (i) refers to each vehicle lights

Index (j) refers to measurement of the sample

Index (t) refers to each number of measurements of T

3.   TESTING CONDITIONS

The testing conditions shall fulfil the requirements of UN/ECE Regulations Nos 4 (1), 6 (2), 7 (3), 19 (4), 23 (5), 38 (6), 48 (7), 100 (8), 112 (9), 119 (10) and 123 (11). The power consumption shall be determined in accordance with point 6.1.4 of UN/ECE Regulation No 112, and points 3.2.1 and 3.2.2 of Annex 10 to that Regulation.

For the low beam adaptive front lighting system (AFS) falling within at least two of the Classes C, E, V or W as defined in Regulation UN/ECE No 123, unless it is agreed with the technical service that Class C is the representative/average LED intensity for the vehicle application, power measurements shall be done at the LED intensity of each class (Pc) as defined in Regulation UN/ECE 123. If Class C is the representative/average LED intensity for the vehicle application, power measurements shall be done in the same way as for any other exterior LED light included in the combination.

Test equipment

The following equipment shall be used, as shown in the Figure below:

—	a power supply unit (i.e. variable voltage supplier);

—	two digital multimeters, one for measuring the DC-current, and the other for measuring the DC-voltage. In the Figure, a possible test set-up is shown, when the DC-voltage meter is integrated in the power supply unit.

Test set-up

Text of image

Measurements and determination of the power savings

For each efficient exterior LED light included in the combination the measurement of the current shall be performed as shown in the Figure at a voltage of 13,2 V. LED module(s) operated by an electronic light source control gear, shall be measured as specified by the applicant.

The manufacturer may request that other measurements of the current shall be done at other additional voltages. In that case, the manufacturer shall hand over verified documentation on the necessity to perform those other measurements to the type-approval authority. The measurements of the currents at each of those additional voltages shall be performed consecutively at least five times. The exact installed voltages and the measured current shall be recorded in four decimals.

The power consumption shall be determined by multiplying the installed voltage with the measured current. The average of the power consumption for each efficient exterior LED light (

) shall be calculated. Each value shall be expressed in four decimals. When a stepper motor or electronic controller is used for the supply of the electricity to the LED lights, the electric load of that component part shall be excluded from the measurement.

Additional measurements for Low beam Adaptive Front Lighting System (AFS)

Table 1

Classes of Low beam AFS

Class	See point 1.3 and footnote 2 of UN/ECE Regulation 123	% LED Intensity	Activation Mode (*1)
C	Base Passing Beam (Country)	100 %	50 km/h < speed < 100 km/h Or when no mode of another passing beam class is activated (V, W, E)
V	Town	85 %	Speed < 50 km/h
E	Motorway	110 %	Speed > 100 km/h
W	Adverse Conditions	90 %	Windshield wiper active > 2 min

Where the power measurements at the LED intensity of each class are needed, after conducting the measurements of each Pc, the power of the Low beam AFS (

) shall be calculated as a weighted average of the LED Power during the WLTC speed bands, with the following Formula 1.

Formula 1

Where:

is the power consumption (mean of the n measurements) for each class;

is the WLTC time percentage per speed band in each class (WLTC last 1 800 s in total):

Table 2

Speed band	Time	WLTC_sharec (%)
< 50 km/h:	1 058 s	0,588 (58,8 %)
50 – 100 km/h	560 s	0,311 (31,1 %)
> 100 km/h	182 s	0,101 (10,1 %)

When the Low beam AFS only has 2 classes not covering all WLTC speeds (e.g. C & V), the weighting of Class C power shall also include the WLTC time not covered by the 2nd class (e.g. Class C time ‘t’ = 0,588 + 0,101)

The resulting power savings of each efficient exterior LED light (ΔPi) shall be calculated with the following Formula 2:

Formula 2

where the power consumption of the corresponding baseline vehicle light is as specified in Table 3:

Table 3

Power consumptions for different baseline vehicle lights

Vehicle light	Total electric power (PB) [W]
Low beam headlamp	137
High beam headlamp	150
Front position	12
License plate	12
Front fog lamp	124
Rear fog lamp	26
Front turn signal lamp	13
Rear turn signal lamp	13
Reversing lamp	52
Cornering lamp	44
Static Bending lamp	44

4.   CALCULATION OF THE CO2 SAVINGS AND STATISTICAL MARGIN

4.1.   Calculation of the CO2 savings

The total CO2 savings of the lighting package shall be calculated in accordance with the specific powertrain of the vehicle (i.e. Conventional, NOVC-HEV).

4.1.1.   Conventional Vehicles (Internal Combustion Engine only)

The CO2 savings shall be calculated in accordance with the following Formula 3:

Formula 3

Where:

v: Mean driving speed of the WLTC [km/h], which is 46,60 km/h

ηA : Efficiency of the alternator, which is 0,67

VPe : Consumption of effective power as specified in Table 4

Table 4

Consumption of effective power

Type of engine	Consumption of effective power (VPe) [l/kWh]
Petrol	0,264
Petrol Turbo	0,280
Diesel	0,220

CF: Conversion factor (l/100 km) - (g CO2/km) [gCO2/l] as specified in Table 5:

Table 5

Fuel conversion factor

Type of fuel	Conversion factor (l/100 km) - (g CO2/km) (CF) [gCO2/l]
Petrol	2 330
Diesel	2 640

UFi : Usage factor for the vehicle light [-] as defined in Table 6.

Table 6

Usage factor for different vehicle lights

Vehicle light	Usage factor (UF) [-]
Low beam headlamp	0,33
High beam headlamp	0,03
Front position	0,36
License plate	0,36
Front fog lamp	0,01
Rear fog lamp	0,01
Front turn signal lamp	0,15
Rear turn signal lamp	0,15
Reversing lamp	0,01
Cornering lamp	0,076
Static Bending lamp	0,15

4.1.2.   Hybrid Vehicles (NOVC-HEV only)

The CO2 savings shall be calculated in accordance with the following Formula 4:

Formula 4

Where:

ηDCDC : Efficiency of the DC-DC converter

: CO2 correction factor

, as defined in paragraph 2.2 of Appendix 2 to Sub-Annex 8 to Annex XXI to Regulation (EU) 2017/1151.

The efficiency of the DC-DC converter (ηDCDC ) shall be evaluated in accordance with the appropriate vehicle architecture, as specified in Table 7:

Table 7

Usage factor for different vehicle lights

#	Architecture	ηDCDC
1	Lights connected in parallel to the low voltage battery (lights fed directly from the high voltage battery via DCDC converter)	0,xx
2	Lights connected in series after the low voltage battery, and the low voltage battery connected in series to the High voltage battery	1
3	High Voltage and low voltage batteries have exactly the same voltage (12 V, 48 V,…) as the lights	1

For architecture #1, the efficiency of the DC-DC converter (ηDCDC ) shall be the highest value resulting from the efficiency tests performed in the operative electric current range. The measuring interval shall be equal or lower than 10 % of the operative electric current range.

4.2.   Calculation of the statistical margin

The statistical margin of the lighting package shall be calculated in accordance with the specific powertrain of the vehicle (i.e. Conventional, NOVC-HEV).

4.2.1.   Conventional Vehicles (Internal Combustion Engine only)

The statistical margin of the results of the testing methodology caused by the measurements shall be quantified. For each efficient exterior LED light included in the package the standard deviation shall be calculated in accordance with Formula 5:

Formula 5

Where:

n: Number of measurements of the sample, which is at least 5

Where the standard deviation of the power consumption of each efficient exterior LED light (

) leads to an error in the CO2 savings (

) that error shall be calculated by means of Formula 6:

Formula 6

4.2.2.   Hybrid Vehicles (NOVC-HEV only)

The statistical margin of the results of the testing methodology caused by the measurements shall be quantified. For each efficient exterior LED light included in the package the standard deviation shall be calculated in accordance with Formula 7:

Formula 7

Where:

n: Number of measurements of the sample, which is at least 5

The CO2-emission correction factor

shall be determined from a set of T measurements performed by the manufacturer, in accordance with paragraph 2.2 of Appendix 2 to Sub-Annex 8 to Annex XXI to Regulation (EU) 2017/1151. For each measurement, electric balance during the test and the measured CO2-emissions shall be recorded.

In order to evaluate the statistical error of

, all T combinations without repetitions of T-1 measurements shall be used to extrapolate T different values of

(i.e.

). The extrapolation shall be performed in accordance with the method defined in paragraph 2.2 of Appendix 2 to Sub-Annex 8 to Annex XXI to Regulation (EU) 2017/1151.

The standard deviation of

shall be calculated in accordance with Formula 8.

Formula 8

Where:

T: Number of measurements performed by the manufacturer for the extrapolation of the

as defined in paragraph 2.2 of Appendix 2 to Sub-Annex 8 to Annex XXI to Regulation (EU) 2017/1151.

: mean of the T values of

Where the standard deviation of the power consumption of each efficient exterior LED light (

) and the standard deviation of the

lead to an error in the CO2 savings (

), that error shall be calculated by means of Formula 9.

Formula 9

4.3.   Statistical margin for Low beam AFS

Where the Low beam AFS is present, formulae 9 shall be adapted to take into account the additional measurements required.

The value of the uncertainty (

) that is to be used for the Low beam AFS shall be calculated with the following formulae 10 and 11:

Formula 10

Formula 11

Where:

n: Number of measurements of the sample, which is at least 5

: mean of the n values of Pc

5.   ROUNDING

The calculated CO2 savings value (

) and the statistical margin of the CO2 saving (

) shall be rounded to a maximum of two decimal places.

Each value used in the calculation of the CO2 savings may be applied unrounded or rounded to the minimum number of decimal places which allows the combined impact of all rounded values on the savings to be lower than 0,25 gCO2/km.

6.   STATISTICAL SIGNIFICANCE

It shall be demonstrated for each type, variant and version of a vehicle fitted with the efficient LED lightings that the uncertainty of the CO2 savings calculated in accordance with Formula 6 or Formula 9 is not greater than the difference between the total CO2 savings and the minimum savings threshold specified in Article 9(1) of Implementing Regulation (EU) No 725/2011 (see Formula 12).

Formula 12

Where:

MT	:	minimum threshold [g CO2/km]
	:	total CO2 saving [g CO2/km]
	:	standard deviation of the total CO2 saving [gCO2/km]

Where the total CO2 emission savings of the efficient LED lighting as determined in accordance with the testing methodology set out in this Annex are below the threshold specified in Article 9(1)(b) of Implementing Regulation (EU) No 725/2011 the second subparagraph of Article 11(2) of that Regulation shall apply.

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(1)   OJ L 4, 7.1.2012, p. 17.

(2)   OJ L 213, 18.7.2014, p. 1.

(3)   OJ L 285, 30.9.2014, p. 1.

(4)   OJ L 250, 22.8.2014, p. 1.

(5)   OJ L 237, 8.8.2014, p. 1.

(6)   OJ L 148, 12.6.2010, p. 55.

(7)   OJ L 323, 6.12.2011, p. 46.

(8)   OJ L 302, 28.11.2018, p. 114.

(9)   OJ L 250, 22.8.2014, p. 67.

(10)   OJ L 89, 25.3.2014, p. 101.

(11)   OJ L 222, 24.8.2010, p. 1.

(*1)  Activation speeds to be checked for each vehicle application in accordance with UN/ECE Regulation No 48 section 6, chapter 6.22, paragraphs 6.22.7.4.1 (class C), 6.22.7.4.2 (class V), 6.22.7.4.3 (class E), 6.22.7.4.4 (class W).