Document ID: chunk:federal_register_of_legislation:F2024L00446:reg:16:p23
Version: federal_register_of_legislation:F2024L00446
Segment Type: reg
Provision Reference: reg 16 (pt 23/108)
Character Range: 948338–951595

be applied if the overall accuracy of the absolute road load of vehicle N is compromised in any way.

              6.8.1. Determination of delta flat belt or chassis dynamometer coefficients

              The delta road load shall be calculated using the following equation:

              where:

              FDj,Delta  is the delta road load at reference speed j, N;

                     FDj,N is the corrected resistance measured on the flat belt or chassis dynamometer at reference speed j calculated according to paragraph 6.7.1. of this annex for vehicle N, N;

                     FDj,R is the corrected resistance of the reference vehicle measured on the flat belt or chassis dynamometer at reference speed j calculated according to paragraph 6.7.1. of this annex for reference vehicle R, N.

              For all calculated FDj,Delta, the coefficients f0,Delta, f1,Delta and f2,Delta in the road load equation shall be calculated with a least squares regression analysis.

              6.8.2. Determination of total road load

              If the interpolation method (see paragraph 3.2.3.2. of Annex B7) is not used, the road load coefficients for vehicle N shall be calculated according to the following equations:

                  where:

              N refers to the road load coefficients of vehicle N;

              R refers to the road load coefficients of reference vehicle R;

                  Delta refers to the delta road load coefficients determined in paragraph 6.8.1. of this annex.

              7. Transferring road load to a chassis dynamometer

              7.1. Preparation for chassis dynamometer test
              7.1.0. Selection of dynamometer operation
              The test shall be carried out in accordance with paragraph 2.4.2.4. of Annex B6.
              7.1.1. Laboratory conditions
              7.1.1.1. Roller(s)
              The chassis dynamometer roller(s) shall be clean, dry and free from foreign material that might cause tyre slippage. The dynamometer shall be run in the same coupled or uncoupled state as the subsequent Type 1 test. Chassis dynamometer speed shall be measured from the roller coupled to the power absorption unit.
              7.1.1.1.1. Tyre slippage
              Additional weight may be placed on or in the vehicle to eliminate tyre slippage. The manufacturer shall perform the load setting on the chassis dynamometer with the additional weight. The additional weight shall be present for both load setting and the emissions and fuel consumption tests. The use of any additional weight shall be recorded.
              7.1.1.2. Room temperature
              The laboratory atmospheric temperature shall be at a set point of 23 °C and shall not deviate by more than ±5 °C during the test unless otherwise required by any subsequent test.
              7.2. Preparation of chassis dynamometer
              7.2.1. Inertia mass setting
              The equivalent inertia mass of the chassis dynamometer shall be set according to paragraph 2.5.3. of this annex. If the chassis dynamometer is not capable to meet the inertia setting exactly, the next higher inertia setting shall be applied with a maximum increase of 10 kg.
              7.2.2. Chassis dynamometer