ANNEX

METHODOLOGY TO DETERMINE THE CO2 SAVINGS OF THE ENGINE-ON COASTING FUNCTION FOR INTERNAL COMBUSTION ENGINE VEHICLES AND CERTAIN NOT OFF-VEHICLE CHARGING HYBRID ELECTRIC VEHICLES

1.   SYMBOLS, UNITS AND PARAMETERS

Latin symbols

CO2	— Carbon dioxide
	— CO2 savings [g CO2/km]
idle_corr	— Correction factor for the idle fuel consumption
BMC	— CO2 emissions of the baseline vehicle during the coasting corresponding manoeuvres under modified testing conditions [g CO2/km]
	— CO2 emissions of the baseline vehicle during the i-th coasting corresponding manoeuvres under modified testing conditions [g CO2/km]
	— CO2 emissions of the baseline vehicle at constant speed k (i.e. 32, 35, 50, 70, 120 km/h) during the i-th constant speed event [g CO2/km]
	— CO2 emissions of the baseline vehicle during the i-th overrun phase under modified testing conditions [g CO2/km]
	— CO2 emissions of the baseline vehicle during the i-th overrun phase under modified testing conditions due to the battery balance [g CO2/km]
	— Distance driven during the i-th overrun event [km]
	— Distance driven during the i-th coasting event [km]
ECE	— Elementary urban driving cycle (part of the NEDC)
EMC	— CO2 emissions of the eco-innovative vehicle under modified testing conditions [g CO2/km]
	— CO2 emissions during the i-th idle phase [g CO2/km]
	— Engine synchronization CO2 emissions during the i-th coasting event [g CO2/km]
	— Measured fuel consumption at constant speed phase k (i.e. 32, 35, 50, 70, 120 km/h) [g/s]
EUDC	— Extra-Urban Driving Cycle (part of the NEDC)
fstandstill	— Idle fuel consumption measured during vehicle standstill [g/s]
fuel_dens	— Fuel density [kg/m3]
facc	— Fuel consumption to accelerate the engine from the idle speed to the transmission speed [l]
	— Driving resistance in ‘neutral’ measured under WLTP conditions for automatic and manual transmission [N] (Section 3.2)
	— Driving resistance during ‘overrun’ measured under WLTP conditions for automatic transmission [N] (Section 4.1)
	— Driving resistance during ‘overrun’ evaluated under NEDC conditions [N] (Section 4.1)
	— Driving resistance in NEDC as converted from WLTP conditions in neutral [N]
	— Driving resistance in WLTP conditions with the x-th gear engaged for manual transmission [N]
Ieng	— Moment of inertia of engine (engine specific) [kgm2]
	— Measured power of the primary battery during the i-th overrun event [W]
	— Measured power of the secondary battery during the i-th overrun event [W]
RDCRW	— Relative coasting distance under real world conditions defined as the distance travelled with coasting active divided by total driving distance per trip [%]
RCDmNEDC	— Relative coasting distance under modified testing conditions defined as the distance travelled with coasting active divided by total driving distance of the mNEDC [%]
UF	— Usage factor of the coasting technology defined as
	— Uncertainty of the CO2 savings [g CO2/km]
	— Standard deviation of the arithmetic mean of the CO2 emissions of the eco-innovative vehicle under modified testing conditions [g CO2/km]
SUF	— Standard deviation of the arithmetic mean of the usage factor
	— Engine drag time of the i-th overrun event [h]
	— Duration of the i-th coasting event [s]
	— Minimum time for constant speed phases after acceleration or coasting deceleration [s]
	— Minimum time after every coasting deceleration to a standstill or constant speed phase [s]
	— Engine friction torque (engine specific) [Nm]
vmin	— Minimum speed for coasting [km/h]
vmax	— Maximum speed for coasting [km/h]
	— Constant driving speed k (i.e. 32, 35, 50, 70, 120 km/h) during the i-th constant speed event [km/h]

Greek symbols

ηDCDC	— DC/DC Converter efficiency, which is set equal to 0,92
ηbat_discharge	— Battery discharge efficiency, which is set equal to 0,94
ηalternator	— Alternator efficiency, which is set equal to 0,67
ΔRESdrag	— Difference between the driving resistance in ‘neutral’ gear position, during ‘overrun’ and measured under WLTP conditions [N]
	— Delta power due to WLTP driving resistance dyno settings occurring in the i-th constant speed event [W]
	— Difference of the vehicle driving resistance between the WLTP and NEDC occurring in the i-th constant speed event [N]
Δtacc	— Time needed to accelerate the engine from idle speed to synchronisation speed [s]
Δγacc	— Delta rotational angle [rad]
Δωacc	— Delta engine speed (from idle speed ωidle to the synchronization speed ωsync) [rad/s]

2.   TEST VEHICLES

The test vehicles shall fulfil the following requirements:

(a)

Eco-innovative vehicle: a vehicle with the innovative technology installed and active in default or predominant driving mode. The predominant driving mode is the driving mode that is always selected when the vehicle is switched on regardless of the operating mode selected when the vehicle was previously shut down. The engine-on coasting function shall not be deactivated by the driver in the predominant driving mode;

(b)

Baseline vehicle: a vehicle that in all aspects is identical to the eco-innovative vehicle with the exception of the innovative technology, which is either not installed or deactivated in default or predominant driving mode; The baseline vehicle tested may be the eco-innovative vehicle on the condition that a short brake action is applied before the deceleration events so as to avoid the coasting events that would normally appear due to the coasting function installed in the eco-innovative vehicle as, in principle, the coasting function can be inhibited by pressing the brake pedal before the deceleration events. The brake action temporarily inhibits the coasting function until the subsequent driving event.

3.   DEFINITION OF THE MODIFIED TESTING CONDITIONS

The steps defining the modified testing conditions are as follows:

1.	Definition of the Road Loads;

2.	Definition of the Coast Down Curve in engine-on coasting mode;

3.	Generation of the modified NEDC speed profile (mNEDC);

4.	Coasting corresponding manoeuvres for the baseline vehicle;

3.1.   Definition of the Road Loads

The road loads of the baseline and eco-innovative vehicle shall be determined in accordance with the procedure set out in Sub-Annex 4 to Annex XXI to Regulation (EU) 2017/1151 and be converted into NEDC road loads for vehicle high and low in accordance with point 2.3.8 of Annex I to Commission Implementing Regulation (EU) 2017/1153 (1).

3.2.   Definition of the Coast Down Curve in engine-on coasting mode

The coast down curve in engine-on coasting mode is defined as the coast down curve with the gear position in ‘neutral’, as determined during the type approval procedure in accordance with Sub-Annex 4 to Annex XXI to Regulation (EU) 2017/1151 and corrected to the corresponding NEDC coast down curve in accordance with point 2.3.8 of Annex I to Implementing Regulation (EU) 2017/1153.

3.3.   Generation of the modified NEDC speed profile (mNEDC)

The speed profile of the mNEDC shall be generated in accordance with the following:

(a)	The test sequence is composed of an urban cycle made of four elementary urban cycles and an extra-urban cycle;

(b)	All acceleration ramps are identical to the NEDC speed profile;

(c)	All constant speed levels are identical to the NEDC speed profile;

(d)	The speed and time tolerances shall be in accordance with paragraph 1.4 of Annex 7 to UN/ECE Regulation No 101;

(e)	The deviation from the NEDC profile shall be minimised and the overall distance must comply with the NEDC specified tolerances;

(f)	The distance at the end of each deceleration phase of the mNEDC profile shall be equal to the distance at the end of each deceleration phase of the NEDC profile;

(g)	During coasting phases the internal combustion engine (ICE) is decoupled and no active correction of the vehicle’s speed trajectory is permitted;

(h)	Lower speed limit for coasting vmin: The coasting mode has to be disabled at the lower speed limit for coasting (15 km/h) by engaging the brake;

(i)	In technically justified cases and in agreement with the type approval authority, the manufacturer may select the speed vmin at a higher speed than 15 km/h;

(j)	Minimum stop time: The minimum time after every coasting deceleration to a standstill or constant speed phase is 2 seconds;

(k)	Minimum time for constant speed phases: The minimum time for constant speed phases after acceleration or coasting deceleration is 2 seconds. For technical reasons this value can be increased and it shall be recorded in the test report;

(l)	The coasting mode can be enabled if the speed is below the maximum speed of the test cycle, i.e. 120 km/h

3.3.1.   Gearshift profile generation for vehicles with manual gearbox

For vehicles with manual gearbox, the gearshift Tables 1 and 2 in Annex 4a of Regulation UNECE 83 shall be adapted on the basis of the following:

1.	The gearshift selection during vehicle acceleration is as defined for the NEDC;

2.	The timing for the downshifts of the modified NEDC differs from the one of the NEDC in order to avoid downshifts during coasting phases (e.g. anticipated before deceleration phases).

The pre-defined shift points for the ECE and EUDC portion of the NEDC, as described in Table 1 and Table 2 of Annex 4a to Regulation UNECE 83, shall be modified in accordance with Table 1 and Table 2 shown below.

Table 1

Operation	Phase	Acceleration (m/s2)	Speed (km/h)	Duration of each		Cumulative time (s)	Gear to be used
				Operation (s)	Phase (s)
Idling	1	0	0	11	11	11	6s PM+5sK1 (1)
Acceleration	2	1,04	0-15	4	4	15	1
Steady speed	3	0	15	9	8	23	1
Deceleration	4	– 0,69	15-10	2	5	25	1
Deceleration, clutch disengaged		– 0,92	10-0	3		28	K1 (1)
Idling	5	0	0	21	21	49	16s PM+5sK(1)
Acceleration	6	0,83	0-15	5	12	54	1
Gear change			15	2		56
Acceleration		0,94	15-32	5		61	2
Steady speed	7	0	32	tconst1	tconst1	61+tconst1	2
Deceleration	8	coast down	[32-dv1]	Δtcd1	Δtcd1 + 8 -Δt1 + 3	61+tconst1+Δtcd1	2
Deceleration		– 0,75	[32-dv1]-10	8-Δt1		69+tconst1+Δtcd1-Δt1	2
Deceleration, clutch disengaged		– 0,92	10-0	3		72+tconst1+Δtcd1-Δt1	K 2 (1)
Idling	9	0	0	21-Δt1		117	16s-Δt1PM+5sK1 (1)
Acceleration	10	0,83	0-15	5	26	122	1
Gear change			15	2		124
Acceleration		0,62	15-35	9		133	2
Gear change			35	2		135
Acceleration		0,52	35-50	8		143	3
Steady speed	11	0	50	tconst2	tconst2	tconst2	3
Deceleration		coast down	[50- dv2]	Δtcd2	Δtcd2	tconst2+Δtcd2	3
Deceleration	12	– 0,52	[50- dv2]-35	8-Δt2	8-Δt2	tconst2+Δtcd2 + 8-Δt2	3
Steady speed	13	0	35	tconst3	tconst3	tconst2+Δtcd2 + 8-Δt2+tconst3	3
Gear change	14		35	2	12+Δtcd3-Δt3	tconst2+Δtcd2 + 10-Δt2+tconst3
Deceleration		coast down	[35- dv3]	Δtcd3		tconst2+Δtcd2 + 10-Δt2+tconst3+Δtcd3	2
Deceleration		– 0,99	[35- dv3]-10	7-Δt3		tconst2+Δtcd2 + 17-Δt2+tconst3+Δtcd3-Δt3	2
Deceleration clutch disengaged		– 0,92	10-0	3		tconst2+Δtcd2 + 20-Δt2+tconst3+Δtcd3-Δt3	K2 (1)
Idling	15	0	0	7-Δt3	7-Δt3	tconst2+Δtcd2 + 27-Δt2+tconst3+Δtcd3-2*Δt3	7s-Δt3PM(1)

Table 2

No of operation	Operation	Phase	Acceleration (m/s2)	Speed (km/h)	Duration of each		Cumulative time(s)	Gear to be used
					Operation (s)	Phase (s)
1	Idling	1	0	0	20	20		K1  (2)
2	Acceleration	2	0,83	0-15	5	41		1
3	Gear change			15	2			—
4	Acceleration		0,62	15-35	9			2
5	Gear change			35	2			—
6	Acceleration		0,52	35-50	8			3
7	Gear change			50	2			—
8	Acceleration		0,43	50-70	13			4
9	Steady speed	3	0	70	tconst4	tconst4		5
9’	Deceleration	3’	coastdown	70-dv4  (*2)	Δtcd4	Δtcd4		5
10	Deceleration	4	coastdown,  (*1)-0,69	dv4  (*2)-50	8-Δtcd4	8-Δtcd4		4
11	Steady speed	5	0	50	69	69		4
12	Acceleration	6	0,43	50-70	13	13		4
13	Steady speed	7	0	70	50	50		5
14	Acceleration	8	0,24	70-100	35	35		5
15	Steady speed (3)	9	0	100	30	30		5 (3)
16	Acceleration (3)	10	0,28	100-120	20	20		5 (3)
17	Steady speed (3)	11	0	120	tconst5	tconst5		5 (3)
17’	Deceleration (3)		coastdown	[120- dv5]	Δtcd5	Δtcd5		5 (3)
18-end	If dv5 ≥ 80
	Deceleration (3)	12	– 0,69	[120-dv5]-80	16-Δt5	34-Δt5		5 (3)
	Deceleration (3)		– 1,04	80-50	8			5 (3)
	Deceleration, clutch disengaged		1,39	50-0	10			K5  (2)
	Idling	13	0	0	20-Δt5	20-Δt5		PM (2)
	If 50 < dv5 < 80
	Deceleration (3)		– 1,04	[120-dv5]-50	8-Δt5	18-Δt5		5 (3)
	Deceleration, clutch disengaged		1,39	50-0	10			K5  (2)
	Idling	13	0	0	20-Δt5	20-Δt5		PM (2)
	If dv5 ≤ 50
	Deceleration, clutch disengaged		1,39	[120-dv5]	10-Δt5	10-Δt5		K5  (2)
	Idling	13	0	0	20-Δt5	20-Δt5		PM (2)

For the definition of the terms in Table 1 and Table 2 please refer to UNECE Regulation 83.

For vehicles with manual transmissions, coasting shall be interrupted during the deceleration from 70 km/h down to 50 km/h as gear shift is commanded from 5th to 4th gear. The gear shift shall interrupt the coasting and the vehicle shall follow the same pre-defined deceleration as in the NEDC until the vehicle reaches 50 km/h. In this case, only the coasting phase before the interruption will be considered in the calculation of the CO2 savings resulting from the implementation of the coasting on function.

3.4.   Coasting corresponding manoeuvres for the baseline vehicle

For each coasting event identified in the mNEDC for the eco-innovative vehicle, a corresponding manoeuvre shall be determined for the baseline vehicle. These manoeuvres shall be composed of a constant speed phase followed by a deceleration phase with engine in overrun conditions (i.e. the engine rotation is caused by the vehicle movement, the gas pedal is released and no fuel is injected), without braking, and they shall fulfil the speed tolerances and distances of the coasting manoeuvres as defined in UNECE Regulation 83. During these manoeuvres, the gearbox shall be engaged in case of automatic transmission, or the speed specific gear shall be engaged as set out in Section 3.3.1 in case of manual transmission.

In order to comply with points (a)-(l) of Section 3.3, the same distance must be covered under the NEDC and mNEDC. Since the distance covered by the baseline vehicle in overrun is shorter than the distance covered during coasting by the eco-innovative vehicle, due to the higher deceleration rate of the baseline vehicle, the difference in the distance to be covered by the baseline vehicle shall be supplemented by constant speed driving phases, where the constant speed driven shall be the speed of the baseline vehicle at the start of the coasting event prior to the engine overrun phases. In case the end speed of the coasting manoeuvre is not zero, the additional distances (Δs) shall be achieved in two sections at start speed and end speed respectively.

To determine the constant speed driving duration before the start of the coasting event

and after the end of the coasting event

, the following system of linear equations (Formula 1) shall be used:

Formula 1

where:

Δs	is the additional distance driven at constant speed by the baseline vehicle in comparison with the eco-innovative vehicle [m]
Δt	is the duration of the additional distance driven at constant speed by the baseline in comparison with the eco-innovative vehicle [s]
scoast	is the distance covered during coasting by the eco-innovative vehicle [m]
sdrag	is the distance covered during overrun by the baseline vehicle [m]
vstart	is the speed at the start of the manoeuvre (coasting or overrun) [m/s]
vend	is the speed at the end of the manoeuvre (coasting or overrun) [m/s]
	is the instant of time in which the overrun event begins [s]
	is the instant of time in which the overrun event ends [s]
tcoast	is the duration of the coasting event [s]
tdrag	is the duration of the overrun event [s].

4.   DETERMINATION OF THE ADDITIONAL PARAMETERS

The following tests shall be performed right after the WLTP Type I test in order to define the additional parameters required in the testing methodology:

—	Coast down in overrun mode (valid for the baseline vehicle) to measure the driving resistance during overrun phases (Section 4.1);

—	Constant speed test (valid for the baseline vehicle) to measure the constant speed fuel consumption. The test is based on a specific testing cycle composed by constant speed segments at 120, 70, 50, 35 and 32 km/h (Section 4.2);

—	Idle test (valid for the eco-innovative vehicle) to measure the idle fuel consumption (Section 4.3);

—	Engine synchronization energy determination (Section 4.4).

4.1.   Coast down in overrun mode (baseline vehicle)

In order to measure the driving resistance in overrun mode, a coast down with the gearbox engaged shall be performed (see Figure 2). The test shall be repeated three times as a minimum and shall be performed after the WLTP type I test during the Type Approval with a maximum time lag of 15 minutes. The coast down curve shall be recorded at least three times in a row.

4.1.1.   Automatic transmission

The vehicle can be accelerated by itself or by the dynamometer to a minimum speed of 130 km/h.

During each coast down, the driving resistance forces, the generator and battery current of all batteries shall be measured with steps of maximum 10 km/h.

The driving resistance in overrun mode shall be converted from WLTP settings to NEDC settings in accordance with Formula 2:

Formula 2

where:

ΔRESdrag	is the difference between the driving resistance in overrun condition and in neutral, measured under WLTP conditions [N]
	is the driving resistance measured as described in Section 3.2 [N]
	is the driving resistance in overrun condition, measured under WLTP conditions [N]
	is the driving resistance in NEDC as converted in accordance with point 2.3.8 of Annex I to Implementing Regulation (EU) 2017/1153, as described in Section 3.2 [N].

4.1.2.   Manual transmission

For vehicles with manual transmission, the coast down shall be repeated at different vehicle speeds and gears, at least three times for each gear:

—	Accelerate by using the engine to minimum 130 km/h and stabilize for 5s, then start the coast down in the highest gear and measure between 120-60 km/h;

—	Accelerate by using the engine to 90 km/h and stabilize for 5s, then start the coast down in gear 5 and measure between 70-60 km/h;

—	Accelerate by using the engine to 70 km/h and stabilize for 5s, then start the coast down in gear 3 and measure between 55-35 km/h;

—	Accelerate by using the engine to 60 km/h and stabilize for 5s, then start the coast down in gear 2 and measure between 40-15 km/h.

During each coast down, the driving resistance forces and the generator and battery current [A] of all batteries shall be measured with steps of maximum 10 km/h.

The driving resistance in overrun mode shall be converted from WLTP settings to NEDC settings, in accordance with Formula 3, for each gear x:

Formula 3

4.1.3.   Load balance of the battery in overrun mode

The load balance of the battery/batteries during the overrun phases shall be calculated in accordance with Formula 4 or 5.

In case the vehicle is equipped with a primary and a secondary battery, Formula 4 applies:

Formula 4

where:

	:	Energy recuperated during the i-th overrun event, as arithmetic mean of the values obtained from each coast down test in overrun mode [Wh];
	:	Duration of the i-th overrun event [h];
	:	Average (over the overrun test repetitions) measured power of the primary battery during the i-th overrun event [W];
	:	Average (over the overrun test repetitions) measured power of the secondary battery during the i-th overrun event [W];
ηDCDC	:	DC/DC Converter efficiency, which is set equal to 0,92; if no DC/DC Converter is present, this value is set equal to 1.

In case only one battery (i.e. the 12V battery) is available, Formula 5 applies instead:

Formula 5

The recuperated energy is converted into CO2 emissions by using Formula 6:

Formula 6

where:

ηbat_discharge	:	Battery discharge efficiency, which is 0,94;
ηalternator	:	Alternator efficiency, which is 0,67;
	:	Distance driven during the i-th overrun event [km];
Vpe	:	Consumption of effective power as specified in Table 3;
CF	:	Conversion factor as defined in Table 4.

Table 3

Consumption of effective power

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

Table 4

Fuel conversion factor

Type of fuel	Conversion factor (CF) g CO2/l
Petrol	2 330
Diesel	2 640

4.2.   Constant speed test

The constant driving speed phase fuel consumption shall be measured on a chassis dynamometer by using the on-board-fuel and/or energy consumption monitoring device (OBFCM) meeting the requirements set out in Annex XXII to Regulation (EU) 2017/1151.

The measurement of the fuel consumption is based on a driving pattern which includes all the NEDC constant driving speed phases at 32, 35, 50, 70 and 120 km/h. To ensure equal NEDC shifting points and selected gears for manual transmission vehicles, the sequence of the constant driving speed phases shall be as specified in Figure 3.

Each constant speed phase has a duration of 90 seconds, subdivided into 20 seconds for speed and emission stabilization, 60 seconds during which OBFCM measurement takes place and 10 seconds preparation time for the driver for the upcoming driving manoeuvre.

The speed and acceleration profiles are described in the Appendix to this Annex.

The constant speed test shall be performed after the Coast Down test in overrun mode is performed as set out in Section 4.1.

In order to obtain the NEDC constant speed fuel consumption, the results from the measurements carried out with the WLTP type approval dynamometer settings (vehicle road load and vehicle weight) have to be corrected to NEDC conditions as follows:

Formula 7

Formula 8

where:

	:	CO2 emissions at constant speed k (i.e. 32, 35, 50, 70, 120 km/h) during the i-th constant speed event [g CO2/km];
	:	Measured (WLTP) fuel consumption at constant speed k (i.e. 32, 35, 50, 70, 120 km/h) as arithmetic mean of the measurements [g/s];
	:	Duration of the i-th constant speed event [s];
	:	Distance driven during the i-th constant speed event [km];
fuel_dens	:	Fuel density [kg/m3];
	:	Delta power due to WLTP driving resistance dyno settings occurring in the i-th constant speed event [kW];
	:	Difference of vehicle driving resistance calculated between the WLTP and NEDC driving resistance dynamometer settings occurring in the i-th constant speed event as determined in Section 4.1 [N];
	:	Constant driving speed k (i.e. 32, 35, 50, 70, 120 km/h) during the i-th constant speed event [km/h].

The generator and battery current of all batteries shall be measured and the battery SOC during each 60s measurement window shall be corrected in accordance with Appendix 2 to Sub-Annex 8 to Annex XXI to Regulation (EU) 2017/1151.

The fuel consumption during each constant speed phase k shall be determined as follows:

Formula 9

Formula 10

where:

J	:	Number of measurement points (J = 60) for each constant speed phase k (32, 35, 50, 70 and 120 km/h);
	:	j-th fuel consumption measure at constant speed phase k (32, 35, 50, 70 and 120 km/h) [g/s];
	:	Standard deviation of the fuel consumption at constant speed phase k (32, 35, 50, 70 and 120 km/h).

4.3.   Idle fuel consumption or idle speed test

The idle fuel consumption during coasting can be directly measured with an OBFCM meeting the requirements set out in Annex XXII to Regulation (EU) 2017/1151, and this measured value can be used for the calculation of

.

As an alternative, Formula 12 can be used to calculate

in accordance with the following methodology:

The engine idle fuel consumption (g/s) shall be measured using an OBFCM meeting the requirements set out in Annex XXII to Regulation (EU) 2017/1151. The measurement shall be performed just after the Type 1 test when the engine is still warm and under the following conditions:

(a)	the velocity of the vehicle is zero;

(b)	the start-stop system is disengaged;

(c)	the battery state of charge is at balance conditions.

The vehicle shall be left to idle for 3 minutes so that it stabilizes. The fuel consumption shall be measured during 2 minutes. The first minute shall be disregarded. The idle fuel consumption shall be calculated as the average fuel consumption of the vehicle during the second minute.

A manufacturer may request that the engine idle fuel consumption measurements are used also for other vehicles belonging to the same interpolation family, provided that the engines run with the same idle speed. The manufacturer shall demonstrate to the type approval authority or technical service that those conditions are met.

Where the idle fuel consumption differs between engine on coasting and idling at standstill, a correction factor shall be applied as determined in accordance with Formula 11:

Formula 11

where:

	mean engine idle speed during coasting determined in accordance with Formula 14 [rpm];
	mean engine idle speed during stand-still determined in accordance with Formula 15 [rpm].

The mean engine idle speed during coasting is the arithmetic mean of the engine idle speeds measured via the OBD port during the deceleration from 130 km/h to 10 km/h, with steps of 10 km/h.

As an alternative, the ratio between the maximal possible engine speed during engine-on coasting and idle speed at standstill can be used.

In case the manufacturer can prove that the increase in engine idle speed that occurs during coasting on phases is lower than 5 % of the idle speed during standstill, idle_corr can be set equal to 1.

The corrected CO2 emissions during each phase

[g CO2/km], derived from the idle fuel consumption, shall be calculated in accordance with Formula 12:

Formula 12

where:

	:	CO2 emissions during the i-th idle phase [gCO2/km];
	:	duration of the i-th coasting event [s];
	:	distance driven during the i-th coasting event [km];
	:	mean idle fuel consumption in standstill conditions [g/s], which is the arithmetic mean of 60 measurements.

The mean idle speed during coasting is measured in steps of 10 km/h, considering U measurements for each step (with a 1s resolution), and shall be calculated in accordance with Formula 13:

Formula 13

Therefore, the mean idle speed during coasting considering all H steps of 10 km/h shall be calculated in accordance with Formula 14:

Formula 14

The mean idle speed in standstill conditions shall be calculated in accordance with Formula 15:

Formula 15

where:

stand_speedl	engine idle speed in standstill conditions during the l-th measurement;
L	number of measurement points.

4.4.   Engine synchronization energy determination

The engine synchronization CO2 emissions during the i-th coasting event

[g CO2/km], shall be determined in accordance with Formula 16:

Formula 16

where:

facc	:	fuel consumption to accelerate the engine from the idle speed to the synchronization speed [l];
CF	:	conversion factor as defined in Table 4 [g CO2/l];
	:	distance driven during the i-th coasting event [km].

Manufacturers shall provide engine synchronization fuel consumption value [l] to the type approval authority/technical service determined in accordance with the following methodology:

4.4.1.   Calculation of fuel consumption to accelerate the engine from the idle speed to the synchronization speed

When a coasting event is completed, an additional amount of energy is required (Eacc) to accelerate the engine to the synchronization speed.

The energy needed to accelerate the vehicle engine to synchronization speed, Eacc, is the sum of the energies associated with the acceleration and the friction work implemented in the vehicle and shall be calculated in accordance with Formula 17:

Formula 17

Eacc = Eacc,kin + Eacc,fric

where:

Eacc,kin	:	Energy associated with the acceleration work implemented in the vehicle [kJ];
Eacc,fric	:	Energy associated with the friction work implemented in the vehicle [kJ].

These energies shall be calculated in accordance with Formulas 18 and 19, respectively.

Formula 18

where:

Ieng	:	Moment of inertia of engine (engine specific) [kgm2];
	:	Delta engine speed (from idle speed ωidle to the target/synchronization speed ωsync) [rad/s].

Formula 19

where:

	:	Engine friction torque (engine specific) [Nm];
Δγacc	:	Delta rotational angle [rad] as determined in accordance with Formula 20.

Formula 20

Δγacceng = (ωidle + 0,5•Δωacc) • Δtacc

with Δtacc as defined in Formula 21:

Formula 21:

Δtacc = tsync – tidle

Finally, the amount of fuel [l] required to reach the synchronization speed, is calculated as follows:

Formula 22

acc = (Eacc,kin + Eacc,fric)•VPe • 3,6

where:

Vpe

:

Consumption of effective power as specified in Table 3 [l/kWh].

5.   DETERMINATION OF THE CO2 EMISSIONS OF THE ECO-INNOVATIVE VEHICLE UNDER MODIFIED TESTING CONDITIONS (EMC)

For each coasting event i, the corresponding CO2 emissions

[g CO2/km] of the eco-innovative vehicle shall be determined in accordance with Formula 23:

Formula 23

where:

	:	CO2 emissions during the i-th idle phase as set out in point 4.3;
	:	Engine synchronization CO2 emissions during the i-th coasting event as set out in point 4.4.

The total CO2 emissions of the eco-innovative vehicle during coasting events under modified testing conditions (EMC) [g CO2/km] shall be determined in accordance with Formula 24:

Formula 24

where

I	:	Total number of coasting events (for the eco-innovative vehicle) and corresponding driving manoeuvres (for the baseline vehicle);
i	:	i-th coasting event (for the eco-innovative vehicle) and corresponding driving manoeuvre (for the baseline vehicle).

6.   DETERMINATION OF THE CO2 EMISSIONS OF THE BASELINE VEHICLE UNDER MODIFIED CONDITIONS (BMC)

For each coasting corresponding manoeuvre i, as described in Section 3.4, the CO2 emissions of the baseline vehicle under modified conditions

[g CO2/km] shall be determined in accordance with Formula 25:

Formula 25

The total CO2 emissions of the baseline vehicle under modified conditions BMC [g CO2/km] shall be determined in accordance with Formula 26:

Formula 26

where:

	CO2 emissions (arithmetic mean) of the baseline vehicle during the i-th overrun phase under modified testing conditions due to the battery balance [g CO2/km] as defined with Formula 6;
	CO2 emissions at constant speed k (i.e. 32, 35, 50, 70, 120 km/h) during the i-th constant speed event [g CO2/km] as defined with Formula 7.

7.   CALCULATION OF CO2 SAVINGS

The CO2 savings of the engine-on coasting function shall be determined in accordance with Formula 27:

Formula 27

where

	:	CO2 savings [g CO2/km];
BMC	:	CO2 emissions of the baseline vehicle during the manoeuvres corresponding with coasting events under modified testing conditions [g CO2/km];
EMC	:	CO2 emissions of the eco-innovative vehicle during coasting events under modified testing conditions [g CO2/km];
UFMC	:	Usage factor of the coasting technology under modified conditions, which is 0,52 for vehicles equipped with automatic transmission and 0,48 for vehicles equipped with manual transmission with an automated clutch.

8.   CALCULATION OF THE UNCERTAINTY

The uncertainty of the CO2 savings

shall not exceed 0,5 g CO2/km.

This uncertainty of the CO2 savings shall be calculated as follows:

Formula 28

where

	:	Standard deviation of the arithmetic mean of the CO2 emissions of the baseline vehicle during the manoeuvres corresponding with coasting events under modified testing conditions [g CO2/km], determined in accordance with Formula 29;
	:	Standard deviation of the arithmetic mean of the CO2 emissions of the eco-innovative vehicle during coasting events under modified testing conditions [g CO2/km] determined in accordance with Formulas 30 to 34;
sUF	:	Standard deviation of the arithmetic mean of the usage factor, which is 0,027.

is determined as follows:

Formula 29

where:

and

is determined as follows, depending on the value of fidle:

If fidle = fidle_meas:

Formula 30

If fidle = fstandstill:

Formula 31

If fidle = idle_corr • fstandstill:

Formula 32

where:

Formula 33

and:

Formula 34

9.   CERTIFICATION OF CO2 SAVINGS BY THE TYPE APPROVAL AUTHORITY

The type approval authority shall, for each vehicle version fitted with the engine-on coasting function, certify the CO2 savings in accordance with Article 11 of Implementing Regulation (EU) No 725/2011, by taking the lowest of the CO2 savings determined respectively for vehicle low and vehicle high of the interpolation family to which the vehicle version belongs.

In determining the CO2 savings and assessing them against the minimum savings threshold of 1 g CO2/km, the uncertainty of the CO2 savings determined in accordance with Section 8 shall be taken into account as set out in Section 10.

The uncertainty of the CO2 savings shall be calculated for both vehicle low and vehicle high of the interpolation family. In case that in one of those vehicles, the criteria set out in sections 8 or 10 are not fulfilled, the type approval authority shall not certify savings for any of the vehicles belonging in the respective interpolation family.

10.   ASSESSMENT AGAINST THE MINIMUM THRESHOLD

Taking into account the uncertainty determined in accordance with section 8, the CO2 savings shall exceed the minimum threshold of 1 g CO2/km specified in Article 9(1) of Implementing Regulation (EU) No 725/2011, as follows:

Formula 35

where

MT	:	Minimum threshold (1 g CO2/km);
	:	CO2 savings [g CO2/km];
	:	uncertainty of the CO2 savings [g CO2/km].

Where the minimum threshold is met in accordance with Formula 35, the second subparagraph of Article 11(2) of Implementing Regulation (EU) No 725/2011 shall apply.

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(1)  Commission Implementing Regulation (EU) 2017/1153 of 2 June 2017 setting out a methodology for determining the correlation parameters necessary for reflecting the change in the regulatory test procedure and amending Regulation (EU) No 2014/2010 (OJ L 175, 7.7.2017, p. 679).

(2)  PM = gearbox in neutral, clutch engaged. K1, K5 = first or second gear engaged, clutch disengaged.

(3)  Additional gears can be used according to manufacturer recommendations if the vehicle is equipped with a transmission with more than five gears.

(*1)  Achieved velocity after 4 seconds with an acceleration of – 0,69 m/s2 is 60,064 km/h. This velocity is also used as gear shift indicator for modified NEDC cycle.

(*2)  dv4 ≥ 60,064 km/h.