Document ID: chunk:federal_register_of_legislation:F2024L00446:reg:16:p27
Version: federal_register_of_legislation:F2024L00446
Segment Type: reg
Provision Reference: reg 16 (pt 27/108)
Character Range: 960067–963366

Bt and Ct are the target road load parameters;
                      Ftj is the target road load at reference speed vj, N;
                      vj is the jth reference speed, km/h.
           8.1.3.2. The measured road load shall be calculated using the following equation:
           where:
           Δv is 5 km/h;
           Fmj is the measured road load for each reference speed vj, N;
           TM is the test mass of the vehicle, kg;
                  mr is the equivalent effective mass of rotating components according to paragraph 2.5.1. of this annex, kg;
           ∆tj is the coastdown time corresponding to speed vj, s.
              8.1.3.3. The coefficients As, Bs and Cs in the road load equation of the simulated road load on the chassis dynamometer shall be calculated using a least squares regression analysis:
              The simulated road load for each reference speed vj shall be determined using the following equation, using the calculated As, Bs and Cs:
              8.1.3.4. For dynamometer load setting, two different methods may be used. If the vehicle is accelerated by the dynamometer, the methods described in paragraph 8.1.3.4.1. of this annex shall be used. If the vehicle is accelerated under its own power, the methods in paragraphs 8.1.3.4.1. or 8.1.3.4.2. of this annex shall be used and the minimum acceleration multiplied by speed shall be 6 m²/sec³. Vehicles which are unable to achieve 6 m2/s3 shall be driven with the acceleration control fully applied.
              8.1.3.4.1. Fixed run method
              8.1.3.4.1.1. The dynamometer software shall perform a total of four coastdowns. From the first coastdown, the dynamometer setting coefficients for the second run shall be calculated according to paragraph 8.1.4. of this annex. Following the first coastdown, the software shall perform three additional coastdowns with either the fixed dynamometer setting coefficients determined after the first coastdown or the adjusted dynamometer setting coefficients according to paragraph 8.1.4. of this annex.
              8.1.3.4.1.2. The final dynamometer setting coefficients A, B and C shall be calculated using the following equations:
              where:
                       At, Bt and Ct are the target road load parameters;
                        are the simulated road load coefficients of the nth run;
                        are the dynamometer setting coefficients of the nth run;
                       n is the index number of coastdowns including the first stabilisation run.
              8.1.3.4.2. Iterative method
              The calculated forces in the specified speed ranges shall either be within ±10 N after a least squares regression of the forces for two consecutive coastdowns when compared with the target values, or additional coastdowns shall be performed after adjusting the chassis dynamometer load setting according to paragraph 8.1.4. of this annex until the tolerance is satisfied.
              8.1.4. Adjustment
              The chassis dynamometer setting load shall be adjusted according to the following equations:
            Therefore:
                      where:
                  Fdj is the initial chassis dynamometer setting load, N;
                   is the adjusted chassis dynamometer setting