CO₂

— Carbon dioxide

— CO₂ savings [g CO₂/km]

idle_corr

— Correction factor for the idle fuel consumption

B_MC

— 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)

E_MC

— 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)

f_standstill

— Idle fuel consumption measured during vehicle standstill [g/s]

fuel_dens

— Fuel density [kg/m³]

f_acc

— 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]

I_eng

— 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]

RDC_RW

— Relative coasting distance under real world conditions defined as the distance travelled with coasting active divided by total driving distance per trip [%]

RCD_mNEDC

— 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]

S_UF

— 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]

v_min

— Minimum speed for coasting [km/h]

v_max

— 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]

η_DCDC

— DC/DC Converter efficiency, which is set equal to 0,92

η_{bat_discharge}

— Battery discharge efficiency, which is set equal to 0,94

η_alternator

— Alternator efficiency, which is set equal to 0,67

ΔRES_drag

— 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]

Δt_acc

— Time needed to accelerate the engine from idle speed to synchronisation speed [s]

Δγ_acc

— Delta rotational angle [rad]

Δω_acc

— Delta engine speed (from idle speed ω_idle to the synchronization speed ω_sync) [rad/s]

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) 2017/115337.

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.

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:

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]

s_coast

is the distance covered during coasting by the eco-innovative vehicle [m]

s_drag

is the distance covered during overrun by the baseline vehicle [m]

v_start

is the speed at the start of the manoeuvre (coasting or overrun) [m/s]

v_end

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]

t_coast

is the duration of the coasting event [s]

t_drag

is the duration of the overrun event [s].

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:

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:

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).

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:

1. (a)

   the velocity of the vehicle is zero;

2. (b)

   the start-stop system is disengaged;

3. (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:

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:

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:

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

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

where:

stand_speed_l

engine idle speed in standstill conditions during the l-th measurement;

L

number of measurement points.