Document ID: chunk:federal_register_of_legislation:F2011C00805:reg:21:p2
Version: federal_register_of_legislation:F2011C00805
Segment Type: reg
Provision Reference: reg 21 (pt 2/7)
Character Range: 220212–223032

some other method of starting-up the dynamometer.

         2.2.3. Use the flywheel or any other system of inertia simulation for the particular inertia class to be used.

Figure 2/1

Diagram illustrating the power absorbed by the chassis dynamometer

 = F = a + b . V2         = (a + b . V2) _ 0.1 . F80       ∆ = (a + b . V2) + 0.1 . F80

         2.2.4. Bring the dynamometer to a speed of 80 km/h.

         2.2.5.  Note the load indicated Fi (N)

         2.2.6.  Bring the dynamometer to a speed of 90 km/h.

         2.2.7.  Disconnect the device used to start-up the dynamometer.

         2.2.8. Note the time taken by the dynamometer to pass from a speed of 85 km/h to a speed of 75 km/h.

         2.2.9. Set the power-absorption device at a different level.

         2.2.10. The requirements of paragraphs 2.2.4. to 2.2.9. shall be repeated sufficiently often to cover the range of loads used.

         2.2.11. Calculate the load absorbed using the formula:

         where:

                   F = load absorbed (N)
                   Mi = equivalent inertia in kg (excluding the inertial effects of the free rear roller)
                   Δ V = Speed deviation in m/s (10 km/h = 2.775 m/s)
                   t = time taken by the roller to pass from 85 km/h to 75 km/h.

         2.2.12. Figure 2/2 shows the load indicated at 80 km/h in terms of load absorbed at 80 km/h.

Figure 2/2

Load indicated at 80 km/h in terms of load absorbed at 80 km/h

         2.2.13. The requirements of paragraphs 2.2.3. to 2.2.12. above shall be repeated for all inertia classes to be used.

         2.3. Calibration of the load indicator as a function of the absorbed load for other speeds. The procedures described in paragraph 2.2. above shall be repeated as often as necessary for the chosen speeds.

         2.4. Verification of the load-absorption curve of the dynamometer from a reference setting at a speed of 80 km/h.

         2.4.1. Place the vehicle on the dynamometer or devise some other method of starting-up the dynamometer.

         2.4.2. Adjust the dynamometer to the absorbed load (F) at 80 km/h.

         2.4.3.  Note the load absorbed at 120, 100, 80, 60, 40 and 20 km/h.

         2.4.4. Draw the curve F(V) and verify that it corresponds to the requirements of paragraph 1.2.2. of this Appendix.

         2.4.5. Repeat the procedure set out in paragraphs 2.4.1. to 2.4.4. above for other values of power F at 80 km/h and for other values of inertias.

         2.5. The same procedure shall be used for force or torque calibration.

         3.  SETTING OF THE DYNAMOMETER

         3.1. Setting method

         3.1.1. Introduction

         This method is not a preferred method and shall be used only with fixed load curve shape dynamometers for determination of load setting at