Document ID: chunk:federal_register_of_legislation:F2024L00446:reg:16:p1
Version: federal_register_of_legislation:F2024L00446
Segment Type: reg
Provision Reference: reg 16 (pt 1/108)
Character Range: 885975–889095

16  2.1  30  2.0

              4.3.1.4.3. If during a measurement in one direction any external factor or driver action occurs that obviously influences the road load test, that measurement and the corresponding measurement in the opposite direction shall be rejected. All the rejected data and the reason for rejection shall be recorded, and the number of rejected pairs of measurement shall not exceed 1/3 of the total number of measurement pairs. In the case of split runs, the rejection criteria shall be applied at each split run speed range.

              Due to uncertainty of data validity and for practical reasons, more than the minimum number of run pairs required in paragraph 4.3.1.4.2. of this annex may be performed, but the total number of run pairs shall not exceed 30 runs including the rejected pairs as described in this paragraph. In this case, data evaluation shall be carried out as described in paragraph 4.3.1.4.2. of this annex starting from the first run pair, then including as many consecutive run pairs as needed to reach the statistical precision on a data set containing no more than 1/3 of rejected pairs. The remaining run pairs shall be disregarded.

              4.3.1.4.4. The following equation shall be used to compute the arithmetic average of the road load where the harmonic average of the alternate coastdown times shall be used:
           where:
                  Δv is 5 km/h;
                   is the harmonic average of alternate coastdown time measurements at velocity vj, seconds, s, given by:
              where:
                     are the harmonic average coastdown times in directions a and b, respectively, corresponding to reference speed , in seconds, s, given by the following two equations:
              and:
                      where:
                  mav is the arithmetic average of the test vehicle masses at the beginning and end of road load determination, kg;
                  mr is the equivalent effective mass of rotating components according to paragraph 2.5.1. of this annex;
              The coefficients, f0, f1 and f2 in the road load equation shall be calculated with a least squares regression analysis.
              In the case that the tested vehicle is the representative vehicle of a road load matrix family, the coefficient f1 shall be set to zero and the coefficients f0 and f2 shall be recalculated with a least squares regression analysis.
              4.3.1.4.5. Correction to reference conditions
              The curve determined in paragraph 4.3.1.4.4. of this annex shall be corrected to reference conditions as specified in paragraph 4.5. of this annex.
              4.3.2. Coastdown method using on-board anemometry
              The vehicle shall be warmed up and stabilised according to paragraph 4.2.4. of this annex.
              4.3.2.1. Additional instrumentation for on-board anemometry
              The on-board anemometer and instrumentation shall be calibrated by means of operation on the test vehicle where such calibration occurs during the warm-up for the test.
              4.3.2.1.1. Relative