Document ID: chunk:federal_register_of_legislation:F2008C00323:reg:120:p1
Version: federal_register_of_legislation:F2008C00323
Segment Type: reg
Provision Reference: reg 120 (pt 1/23)
Character Range: 238359–241488

120       1.57 A 10-4  0.14

           5.1.2. On the dynamometer

           5.1.2.1. Measurement equipment and accuracy

           The equipment shall be identical to that used on the road.

           5.1.2.2. Test procedure

           5.1.2.2.1. Install the vehicle on the test dynamometer.

           5.1.2.2.2. Adjust the tyre pressure (cold) of the driving wheels as required by the dynamometer.

           5.1.2.2.3. Adjust the equivalent inertia of the dynamometer.

           5.1.2.2.4. Bring the vehicle and dynamometer to operating temperature in a suitable manner.

           5.1.2.2.5. Carry out the operations specified in paragraph 5.1.1.2. above (with the exception of paragraphs 5.1.1.2.4. and 5.1.1.2.5.), replacing M by I in the formula set out in paragraph 5.1.1.2.7.

           5.1.2.2.6. Adjust the brake to reproduce the corrected power (paragraph 5.1.1.2.8.) and to take into account the difference between the vehicle mass (M) on the track and the equivalent inertia test mass (I) to be used. This may be done by calculating the mean corrected road coast down time from V2 to V1 and reproducing the same time on the dynamometer by the following relationship:

             k = value specified in paragraph 5.1.1.2.8. above.

           5.1.2.2.7. The power Pa to be absorbed by the dynamometer shall be determined in order to enable the same power (paragraph 5.1.1.2.8.) to be reproduced for the same vehicle on different days.

           5.2. Torque measurements method at constant speed

           5.2.1. On the road

           5.2.1.1. Measurement equipment and error

           Torque measurement shall be carried out with an appropriate measuring device accurate to within  2 per cent.

           Speed measurement shall be accurate to within  2 per cent.

           5.2.1.2. Test procedure

           5.2.1.2.1. Bring the vehicle to the chosen stabilised speed V.

           5.2.1.2.2. Record the torque Ct and speed over a period of at least 20 seconds. The accuracy of the data recording system shall be at least  1 Nm for the torque and  0.2 km/h for the speed.

           5.2.1.2.3. Differences in torque Ct and speed relative to time shall not exceed 5 per cent for each second of the measurement period.

           5.2.1.2.4. The torque Ct1 is the average torque derived from the following   formula:

           5.2.1.2.5. The test shall be carried out three times in each direction. Determine the average torque from these six measurements for the reference speed. If the average speed deviates by more than 1 km/h from the reference speed, a linear regression shall be used for calculating the average torque.

           5.2.1.2.6. Determine the average of these two torques Ct1 and Ct2, i.e. Ct.

           5.2.1.2.7. The average torque CT determined on the track shall be corrected to the reference ambient conditions as follows:

CTcorrected  =  K . CTmeasured

           where K has the value specified in paragraph 5.1.1.2.8. of this Appendix.

5.2.2. On the dynamometer

           5.2.2.1. Measurement equipment and error

           The equipment shall