Document ID: chunk:federal_register_of_legislation:F2024L00446:reg:16:p13
Version: federal_register_of_legislation:F2024L00446
Segment Type: reg
Provision Reference: reg 16 (pt 13/108)
Character Range: 920002–922968

axles belong to different energy efficiency classes, the weighted mean shall be used, calculated using the equation in paragraph 3.2.3.2.2.2. of Annex B7.
              If the same tyres were fitted to test vehicles L and H, the value of RRind when using the interpolation method shall be set to RRH.
              5.1.2. For the calculation of the running resistance of vehicles of a road load matrix family, the vehicle parameters described in paragraph 4.2.1.4. of this annex and the running resistance coefficients of the representative test vehicle determined in paragraph 4.4. of this annex shall be used.
              5.1.2.1. The running resistance for an individual vehicle shall be calculated using the following equation:
              where:
                  Cc is the calculated running resistance as a function of vehicle velocity, Nm;
                  c0 is the constant running resistance coefficient, Nm, defined by the equation:
c0 = r'/1.02 × Max((0.05 × 1.02 × c0r/r' + 0.95 × (1.02 × c0r/r' × TM/TMr +  × 9.81 × TM));
(0.2 × 1.02 × c0r/r' + 0.8 × (1.02 × c0r/r' × TM/TMr +  × 9.81 × TM)))

                  c0r is the constant running resistance coefficient of the representative vehicle of the road load matrix family, Nm;
                  c1 is the first order running resistance coefficient, Nm/(km/h), and shall be set to zero;
                  c2 is the second order running resistance coefficient, Nm/(km/h)², defined by the equation:
c2 = r'/1.02 × Max((0.05 × 1.02 × c2r/r' + 0.95 × 1.02 × c2r/r' × Af / Afr); (0.2 × 1.02 × c2r/r' + 0.8 × 1.02 ×c2r/r' × Af / Afr))

                  c2r is the second order running resistance coefficient of the representative vehicle of the road load matrix family, N/(km/h)2;
              v is the vehicle speed, km/h;
                  TM is the actual test mass of the individual vehicle of the road load matrix family, kg;
                  TMr is the test mass of the representative vehicle of the road load matrix family, kg;
                  Af is the frontal area of the individual vehicle of the road load matrix family, m²;
                  Afr is the frontal area of the representative vehicle of the road load matrix family, m2;
                  RR is the tyre rolling resistance of the individual vehicle of the road load matrix family, kg/tonne;
                  RRr is the tyre rolling resistance of the representative vehicle of the road load matrix family, kg/tonne;
                  r' is the dynamic radius of the tyre on the chassis dynamometer obtained at 80 km/h, m;
                  1.02 is an approximate coefficient compensating for drivetrain losses.
              5.2. Calculation of the default road load based on vehicle parameters
              5.2.1. As an alternative for determining road load with the coastdown or torque meter method, a calculation method for default road load may be used.
              For the calculation of a default road load based