Commission Regulation (EU) 2017/1151 of 1 June 2017 supplementing Regulation (EC) No 715/2007 of the European Parliament and of the Council on type-approval of motor vehicles with respect to emissions from light passenger and commercial vehicles (Euro 5 and Euro 6) and on access to vehicle repair and maintenance information, amending Directive 2007/46/EC of the European Parliament and of the Council, Commission Regulation (EC) No 692/2008 and Commission Regulation (EU) No 1230/2012 and repealing Commission Regulation (EC) No 692/2008 (Text with EEA relevance)

Appendix 7a Verification of overall trip dynamics

1.INTRODUCTION

This Appendix describes the calculation procedures to verify the overall trip dynamics, to determine the overall excess or absence of dynamics during urban, rural and motorway driving.

2.SYMBOLS, PARAMETERS AND UNITS

RPARelative Positive Acceleration

—

difference

—

larger

≥

—

larger or equal

—

per cent

—

smaller

≤

—

smaller or equal

—

acceleration [m/s²]

a_i

—

acceleration in time step i [m/s²]

a_pos

—

positive acceleration greater than 0,1 m/s² [m/s²]

a_pos,i,k

—

positive acceleration greater than 0,1 m/s² in time step i considering the urban, rural and motorway shares [m/s²]

a_res

—

acceleration resolution [m/s²]

d_i

—

distance covered in time step i [m]

d_i,k

—

distance covered in time step i considering the urban, rural and motorway shares [m]

Index (i)

—

discrete time step

Index (j)

—

discrete time step of positive acceleration datasets

Index (k)

—

refers to the respective category (t=total, u=urban, r=rural, m=motorway)

M_k

—

number of samples for urban, rural and motorway shares with positive acceleration greater than 0,1 m/s²

N _k

—

total number of samples for the urban, rural and motorway shares and the complete trip

RPA_k

—

relative positive acceleration for urban, rural and motorway shares [m/s² or kWs/(kg*km)]

t_k

—

duration of the urban, rural and motorway shares and the complete trip [s]

T4253H

—

compound data smoother

—

vehicle speed [km/h]

ν_i

—

actual vehicle speed in time step i [km/h]

ν_i,k

—

actual vehicle speed in time step i considering the urban, rural and motorway shares [km/h]

—

actual vehicle speed per acceleration in time step i [m²/s³ or W/kg]

—

actual vehicle speed per positive acceleration greater than 0,1 m/s² in time step j considering the urban, rural and motorway shares [m²/s³ or W/kg].

—

95^th percentile of the product of vehicle speed per positive acceleration greater than 0,1 m/s² for urban, rural and motorway shares [m²/s³ or W/kg]

—

average vehicle speed for urban, rural and motorway shares [km/h]

3.TRIP INDICATORS

3.1. Calculations

3.1.1. Data pre-processing

Dynamic parameters like acceleration, or RPA shall be determined with a speed signal of an accuracy of 0,1 % for all speed values above 3 km/h and a sampling frequency of 1 Hz. This accuracy requirement is generally fulfilled by signals obtained from a wheel (rotational) speed sensor.

The speed trace shall be checked for faulty or implausible sections. The vehicle speed trace of such sections is characterised by steps, jumps, terraced speed traces or missing values. Short faulty sections shall be corrected, for example by data interpolation or benchmarking against a secondary speed signal. Alternatively, short trips containing faulty sections could be excluded from the subsequent data analysis. In a second step the acceleration values shall be calculated and ranked in ascending order, as to determine the acceleration resolution .

If , the vehicle speed measurement is sufficiently accurate.

If , data smoothing by using a T4253H Hanning filter shall be performed

The T4235 Hanning filter performs the following calculations: The smoother starts with a running median of 4, which is centred by a running median of 2. The filter then re-smoothes these values by applying a running median of 5, a running median of 3, and hanning (running weighted averages). Residuals are computed by subtracting the smoothed series from the original series. This whole process is then repeated on the computed residuals. Finally, the smoothed final speed values are computed by summing up the smoothed values obtained the first time through the process with the computed residuals.

The correct speed trace builds the basis for further calculations and binning as described in paragraph 8.1.2.

3.1.2. Calculation of distance, acceleration and

The following calculations shall be performed over the whole time based speed trace (1 Hz resolution) from second 1 to second t_t (last second).

The distance increment per data sample shall be calculated as follows:

where:

d_i

is the distance covered in time step i [m]

ν _i

is the actual vehicle speed in time step i [km/h]

N _t

is the total number of samples

The acceleration shall be calculated as follows:

where:

a_i

is the acceleration in time step i [m/s²]. For i = 1: , for : .

The product of vehicle speed per acceleration shall be calculated as follows:

where:

is the product of the actual vehicle speed per acceleration in time step i [m²/s³ or W/kg].

3.1.3. Binning of the results

After the calculation of a_i and , the values v_i , d_i , a_i and shall be ranked in ascending order of the vehicle speed.

All datasets with belong to the ‘urban’ speed bin, all datasets with belong to the ‘rural’ speed bin and all datasets with belong to the ‘motorway’ speed bin.

The number of datasets with acceleration values shall be bigger or equal to 150 in each speed bin.

For each speed bin the average vehicle speed shall be calculated as follows:

where:

N_k

is the total number of samples of the urban, rural, and motorway shares.

3.1.4. Calculation of per speed bin

The 95^th percentile of the values shall be calculated as follows:

The values in each speed bin shall be ranked in ascending order for all datasets with and the total number of these samples M_k shall be determined.