Document ID: chunk:federal_register_of_legislation:F2024L00446:reg:16:p8
Version: federal_register_of_legislation:F2024L00446
Segment Type: reg
Provision Reference: reg 16 (pt 8/108)
Character Range: 905850–909128

equation:
              .
                     shall be no greater than 0.05 and may be disregarded if  is not greater than ±0.005 m/s2;
                  mst is the test vehicle mass at the start of the measurements and shall be measured immediately before the warm-up procedure and no earlier, kg;
                  mr is the equivalent effective mass of rotating components according to paragraph 2.5.1. of this annex, kg;
                  rj is the dynamic radius of the tyre determined at a reference point of 80 km/h or at the highest reference speed point of the vehicle if this speed is lower than 80 km/h, calculated using the following equation:
                                where:
                  n is the rotational frequency of the driven tyre, s-1;
                   is the arithmetic average acceleration, m/s2, calculated using the following equation:
                  where:
                  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  have been obtained, for which  satisfies the precision ρj according to the following equation:
              where:
           n is the number pairs of measurements for ;
                   is the running resistance at the speed vj, Nm, given by the equation:
                         where:
                   is the arithmetic average torque of the ith pair of measurements at speed vj, Nm, and given by:

              where:
                      Cjmai and Cjmbi are the arithmetic average torques of the ith measurement at speed  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:
                  h is a coefficient as a function of n as given in Table A4/4 in paragraph 4.3.1.4.2. of this annex.
              4.4.4. 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)
              The following least squares regression curve of arithmetic average running resistance shall be fitted to all the data pairs (vjm, Cjm) at all reference speeds described in paragraph 4.4.2.1. of this annex to determine the coefficients c0, c1 and c2.
              The coefficients, c0, c1 and c2 as well as the coastdown times measured on the chassis dynamometer (see paragraph 8.2.4. of this annex) shall be recorded.
              In the case that the tested vehicle is the representative vehicle of a road load matrix family, the coefficient c1 shall be set to zero and the coefficients c0 and c2 shall be recalculated with a least squares regression analysis.
              4.5. Correction to reference conditions and measurement equipment
              4.5.1. Air resistance correction factor
              The correction factor for air resistance K2 shall be determined using the following equation:
           where:
                  T