EN
10.11.2022
Official Journal of the European Union
L 290/287
where: n is the rotational frequency of the driven tyre, s-1; αj is the arithmetic average acceleration, m/s2, calculated using the following equation:
αj ¼
k 1 Ü 3:6
Pk
i¼1 ti vji
kÜ
where:
Pk
Ä
2 i¼1 ti
Pk
i¼1 ti
Ä
hP
Pk
i¼1 vji i2
k i¼1 ti
ti is the time at which the ith data set was sampled, s. 4.4.3.2.
Measurement precision The measurements shall be carried out in opposite directions until a minimum of three pairs of measurements at each reference speed vi have been obtained, for which Cj satisfies the precision ρj according to the following equation:
hÜs ρj ¼ pﬃﬃﬃ Ï 0:030 n Ü Cj
where:
n is the number pairs of measurements for Cjm; Cj is the running resistance at the speed vi, Nm, given by the equation:
Cj ¼
where: Cjmi
1 n
Pn
i¼1
Cjmi
is the arithmetic average torque of the ith pair of measurements at speed vj, Nm, and given by:
Cjmi ¼
1 Ü ðCjmai þ Cjmbi Þ 2
where: Cjmai and Cjmbi
are the arithmetic average torques of the ith measurement at speed vj determined in paragraph 4.4.3.1. of this annex for each direction, a and b respectively, Nm;
s
is the standard deviation, Nm, calculated using the following equation: vﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃﬃ u k u 1 X s¼t ðCjmi Ä Cj Þ2 k Ä 1 i¼1
h 4.4.4.
is a coefficient as a function of n as given in Table A4/4 in paragraph 4.3.1.4.2. of this annex.
Running resistance curve determination The arithmetic average speed and arithmetic average torque at each reference speed point shall be calculated using the following equations: Vjm = ½ × (vjma + vjmb) Cjm = ½ × (Cjma +Cjmb)