Document ID: chunk:federal_register_of_legislation:F2024C00356:reg:21:p32
Version: federal_register_of_legislation:F2024C00356
Segment Type: reg
Provision Reference: reg 21 (pt 32/35)
Character Range: 376056–379083

cent of the particle counter nominal flow rate when checked with a calibrated flow meter.
              2.3.3. Each day, following the application of a HEPA filter of at least class H13 of EN 1822:2008, or equivalent performance, to the inlet of the particle counter, the particle counter shall report a concentration of ≤ 0.2 cm-3. Upon removal of this filter, the particle counter shall show an increase in measured concentration to at least 100 particles cm-3 when challenged with ambient air and a return to ≤ 0.2 cm-3 on replacement of the HEPA filter.
              2.3.4. Prior to the start of each test, it shall be confirmed that the measurement system indicates that the evaporation tube, where featured in the system, has reached its correct operating temperature.
              2.3.5. Prior to the start of each test, it shall be confirmed that the measurement system indicates that the diluter PND1 has reached its correct operating temperature.

Annex 4a - Appendix 6
  Verification of simulated inertia
              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. of this appendix.
              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:

 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 inertia is appended.
               Thus, total inertia is expressed as follows:
 I       =  Im+ F1 / 
 Where:
 Im         can be calculated or measured by traditional methods,
 F1         can be measured on the dynamometer,
           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 Appendix 1) within the following limits:
              3.1.1. 5 per cent of the