Division 6.6.3 Correcting measured chassis dynamometer forces to those on a flat surfaceF1

The measured forces on the chassis dynamometer shall be corrected to a reference equivalent to the road (flat surface) and the result shall be referred to as f_j.

$f_{j} = f_{jDyno} \times c1 \times \sqrt{\frac{1}{\frac{R_{Wheel}}{R_{Dyno}} \times c2 + 1}} + f_{jDyno} \times (1 - c1)$

where:

is the tyre rolling resistance fraction of f_jDyno;

is a chassis dynamometer-specific radius correction factor;

f_jDyno

is the force calculated in paragraph 6.5.2.3.3. for each reference speed j, N;

R_Wheel

is one-half of the nominal design tyre diameter, m;

R_Dyno

is the radius of the chassis dynamometer roller, m.

The manufacturer and the approval authority shall agree on the factors c1 and c2 to be used, based on correlation test evidence provided by the manufacturer for the range of tyre characteristics intended to be tested on the chassis dynamometer.

As an alternative the following conservative equation may be used:

$f_{j} = f_{jDyno} \times \sqrt{\frac{1}{\frac{R_{Wheel}}{R_{Dyno}} \times 0,2 + 1}}$

C2 shall be 0,2 except that 2,0 shall be used if the road load delta method (see paragraph 6.8.) is used and the road load delta calculated in accordance with paragraph 6.8.1. is negative.

Annotations

Textual amendments

F1: Substituted by Commission Regulation (EU) 2018/1832 of 5 November 2018 amending Directive 2007/46/EC of the European Parliament and of the Council, Commission Regulation (EC) No 692/2008 and Commission Regulation (EU) 2017/1151 for the purpose of improving the emission type approval tests and procedures for light passenger and commercial vehicles, including those for in-service conformity and real-driving emissions and introducing devices for monitoring the consumption of fuel and electric energy (Text with EEA relevance).