Appendix 5 F1

The Moving Averaging Window method is used to verify the overall trip dynamics. The test is divided in sub-sections (windows) and the subsequent analysis aims at determining whether the trip is valid for RDE purposes. The ‘normality’ of the windows is conducted by comparing their CO ₂ distance-specific emissions with a reference curve obtained from the vehicle CO ₂ emissions measured in accordance with the WLTP procedure.

Index (i) refers to the time step

Index (j) refers to the window

Index (k) refers to the category (t = total, u = urban, r = rural, m- = motorway) or to the CO ₂ characteristic curve (cc)

The instantaneous emissions calculated in accordance with Appendix 4 shall be integrated using a moving averaging window method, based on the reference CO ₂ mass.

The principle of the calculation is as follows: The RDE distance-specific CO ₂ mass emissions are not calculated for the complete data set, but for sub-sets of the complete data set, the length of these sub-sets being determined so as to match always the same fraction of the CO ₂ mass emitted by the vehicle over the WLTP cycle. The moving window calculations are conducted with a time increment Δt corresponding to the data sampling frequency. These sub-sets used to calculate the vehicle on-road CO ₂ emissions and its average speed are referred to as ‘averaging windows’ in the following sections.

The calculation described in the present point shall be run from the first data point (forward).

The following data shall not be considered for the calculation of the CO ₂ mass, the distance and the vehicle average speed in the averaging windows:

• The periodic verification of the instruments and/or after the zero drift verifications;

• Vehicle ground speed is smaller than 1 km/h.

The calculation shall start from when vehicle ground speed is higher than or equal to 1 km/h and include driving events during which no CO ₂ is emitted and where the vehicle ground speed is higher than or equal to 1 km/h.

The mass emissions $M_{{\mathrm{CO}}_2\mathrm{,j}}$ shall be determined by integrating the instantaneous emissions in g/s as specified in Appendix 4 to this Annex.

The duration ( t _{2 ,j} – t _{1 ,j} ) of the j ^th averaging window is determined by:

Where:

$M_{{\mathrm{CO}}_2}\left(t_{\mathrm{i,j}}\right)$ is the CO ₂ mass measured between the test start and time t _i,j , [g];

$M_{{\mathrm{CO}}_2,\mathrm{ref}}$ is the half of the CO ₂ mass emitted by the vehicle over the WLTP test conducted in accordance with Sub-Annex 6 to Annex XXI of this Regulation.

During type approval the CO ₂ reference value shall be taken from the WLTP performed during type approval testing of the individual vehicle.

For ISC testing purposes, the reference CO ₂ mass shall be obtained from point 12 of the Transparency list 1 of Appendix 5 of Annex II with interpolation between vehicle H and vehicle L (if relevant) as defined in Sub-Annex 7 of Annex XXI, using Test mass and Road load coefficients (f0, f1 & f2) obtained from the Certificate of Conformity for the individual vehicle as defined in Annex IX. The value for OVC-HEV vehicles is to be obtained from the WLTP test conducted using the Charge Sustaining mode.

t _{2 ,j} shall be selected such as:

Where Δt is the data sampling period.

The CO ₂ masses $M_{{\mathrm{CO}}_2,j}$ in the windows are calculated by integrating the instantaneous emissions calculated as specified in Appendix 4 to this Annex.

The following shall be calculated for each window determined in accordance with point 3.1.

• The distance-specific CO ₂ emissions $M_{{\mathrm{CO}}_2,\mathrm{d,j}}$;

• The average vehicle speed ${\bar{v}}_j$.

The reference dynamic conditions of the test vehicle are defined from the vehicle CO ₂ emissions versus average speed measured at type approval on the Type 1 test and referred to as ‘vehicle CO ₂ characteristic curve’. To obtain the distance specific CO ₂ emissions, the vehicle shall be tested on the WLTP cycle in accordance with Annex XXI to this Regulation.

The distance-specific CO ₂ emissions to be considered in this paragraph for the definition of the reference curve shall be obtained from point 12 of the Transparency list 1 of Appendix 5 of Annex II with interpolation between vehicle H and vehicle L (if relevant) as defined in Sub-Annex 7 of Annex XXI, using Test mass and Road load coefficients (f0, f1 & f2) obtained from the Certificate of Conformity for the individual vehicle as defined in Annex IX. The value for OVC-HEV vehicles is to be that obtained from the WLTP test conducted using the Charge Sustaining mode.

During type approval, the values shall be taken from the WLTP performed during type approval testing of the individual vehicle.

The reference points P ₁ , P ₂ and P ₃ required to define the vehicle CO ₂ characteristic curve shall be established as follows:

$\overline{v_{P1}}$ = 18,882 km/h (Average Speed of the Low Speed phase of the WLTP cycle)

$M_{{\mathrm{CO}}_2{\mathrm{,d,P}}_1}$ = Vehicle CO ₂ emissions over the Low Speed phase of the WLTP cycle [g/km]

$\overline{v_{P2}}$ = 56,664 km/h (Average Speed of the High Speed phase of the WLTP cycle)

$M_{{\mathrm{CO}}_2{\mathrm{,d,P}}_2}$ = Vehicle CO ₂ emissions over the High Speed phase of the WLTP cycle [g/km]

$\overline{v_{P3}}$ = 91,997 km/h (Average Speed of the Extra High Speed phase of the WLTP cycle)

$M_{{\mathrm{CO}}_2{\mathrm{,d,P}}_3}$ = Vehicle CO ₂ emissions over the Extra High Speed phase of the WLTP cycle [g/km]

Using the reference points defined in point 4.2, the characteristic curve CO ₂ emissions are calculated as a function of the average speed using two linear sections ( P ₁ , P ₂ ) and ( P ₂ , P ₃ ). The section ( P ₂ , P ₃ ) is limited to 145 km/h on the vehicle speed axis. The characteristic curve is defined by equations as follows:

For the section ( P ₁ , P ₂ ):

with : $a_1=\left(M_{{\mathrm{CO}}_2{\mathrm{,d,P}}_2}-M_{{\mathrm{CO}}_2{\mathrm{,d,P}}_1}\right)∕\left(\overline{v_{P2}}-\overline{v_{P1}}\right)$

and : $b_1=M_{{\mathrm{CO}}_2{\mathrm{,d,P}}_1}-a_1\overline{v_{P1}}$

For the section ( P ₂ , P ₃ ):

with : $a_2=\left(M_{{\mathrm{CO}}_2{\mathrm{,d,P}}_3}-M_{{\mathrm{CO}}_2{\mathrm{,d,P}}_2}\right)∕\left(\overline{v_{P3}}-\overline{v_{P2}}\right)$

and : $b_2=M_{{\mathrm{CO}}_2{\mathrm{,d,P}}_2}-a_2\overline{v_{P2}}$

Urban windows are characterized by average vehicle speeds ${\bar{v}}_j$ lower than 45 km/h.

Rural windows are characterized by average vehicle speeds ${\bar{v}}_j$ greater than or equal to 45 km/h and lower than 80 km/h.

For N2 category vehicles that are equipped in accordance with F2Regulation 36B of the Road Vehicles (Construction and Use) Regulations 1986 with a device limiting vehicle speed to 90 km/h, rural windows are characterized by average vehicle speeds ${\bar{v}}_j$ lower than 70 km/h.

Motorway windows are characterized by average vehicle speeds ${\bar{v}}_j$ greater than or equal to 80 km/h and lower than 145 km/h

For N2 category vehicles that are equipped in accordance with F3Regulation 36B of the Road Vehicles (Construction and Use) Regulations 1986 with a device limiting vehicle speed to 90 km/h, motorway windows are characterized by average vehicle speeds ${\bar{v}}_j$ greater than or equal to 70 km/h and lower than 90 km/h.

The upper tolerance of the vehicle CO ₂ characteristic curve is tol _1H = 45 % for urban driving and tol _1H = 40 % for rural and motorway driving.

The lower tolerance of the vehicle CO ₂ characteristic curve is tol _1L = 25 % for ICE and NOVC-HEV vehicles and tol _1L = 100 % for OVC-HEV vehicles.

The test is valid when it comprises at least 50 % of the urban, rural and motorway windows that are within the tolerances defined for the CO ₂ characteristic curve.

For NOVC-HEVs and OVC-HEVs, if the minimum requirement of 50 % between tol _1H and tol _1L is not met, the upper positive tolerance tol _1H may be increased by steps of 1 % until the 50 % target is reached. When using this mechanism, the value of tol _1H shall never exceed 50 %.