Document ID: chunk:federal_register_of_legislation:F2011C00805:reg:120:p2
Version: federal_register_of_legislation:F2011C00805
Segment Type: reg
Provision Reference: reg 120 (pt 2/23)
Character Range: 238575–241757

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 be identical to that used on the road.

           5.2.2.2. Test procedure

           5.2.2.2.1. Perform the operations specified in paragraphs 5.1.2.2.1. to 5.1.2.2.4. above.

           5.2.2.2.2. Perform the operations specified in paragraphs 5.2.1.2.1. to 5.2.1.2.4. above.

           5.2.2.2.3. Adjust the power absorption unit to reproduce the corrected total track torque indicated in paragraph 5.2.1.2.7. above.

           5.2.2.2.4. Proceed with the same operations as in paragraph 5.1.2.2.7., for the same purpose.

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Annex 4 - Appendix 4

VERIFICATION OF INERTIAS OTHER THAN MECHANICAL

         1.  OBJECT

         The method described in this Appendix makes it possible to check that the simulated total inertia of the dynamometer is carried out satisfactorily in the running phase of the operating cycle. The manufacturer of the dynamometer shall specify a method for verifying the specifications according to paragraph 3. below.

         2.   PRINCIPLE

         2.1.  Drawing-up working equations

         Since the dynamometer is subjected to variations in the rotating speed of the roller(s), the force at the surface of the roller(s) can be expressed by the formula:

F = I. = IM . + F1

         where:

               F = force at the surface of the roller(s),

               I = total inertia of the dynamometer (equivalent inertia of the vehicle: see the table in paragraph 5.1.),

               IM = inertia of the mechanical masses of the dynamometer,

               γ = tangential acceleration at roller surface,

               F1 =  inertia force.

         Note:  An explanation of this formula with reference to dynamometers with mechanically simulated inertias is appended.

         Thus, total inertia is expressed as follows:

 I = Im+ F1 /γ

         where:

         Im can be calculated or measured by traditional methods,

         F1 can be measured on the dynamometer,

         γ can be calculated from the peripheral speed of the rollers.

         The total inertia (I) will be determined during an acceleration or deceleration test with values higher than or equal to those obtained on an operating cycle.

         2.2.  Specification for the calculation of total inertia

         The test and calculation methods shall make it possible to determine the total inertia I with a relative error (∆I/I) of less than  2 per cent.

         3.   SPECIFICATION

         3.1.  The mass of the simulated total inertia I shall remain the same as the theoretical value of the equivalent inertia (see paragraph 5.1. of Annex 4) within the following limits:

         3.1.1.   5 per cent of the theoretical value for each instantaneous value;

         3.1.2.   2 per cent of the theoretical value for the average value calculated for each sequence of the cycle.

         3.2.  The limit given in paragraph 3.1.1. above