Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:13:p56
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 13 (pt 56/56)
Character Range: 448076–449272

ASTM E 29–06B. No rounding of intermediate values leading to the final brake specific emission result is permissible.
              10.5. Determination of particle number background
              10.5.1. At the engine manufacturer's request, dilution tunnel background particle number concentrations may be sampled, prior to or after the test, from a point downstream of the particle and hydrocarbon filters into the particle number measurement system, to determine the tunnel background particle concentrations.
              10.5.2. Subtraction of particle number tunnel background concentrations shall not be allowed for type approval, but may be used at the manufacturer's request, with the prior approval of the Type Approval Authority , for conformity of production testing, if it can be demonstrated that tunnel background contribution is significant, which can then be subtracted from the values measured in the diluted exhaust.
Annex 4 ‑ Appendix 1 WHTC engine dynamometer schedule
Time  Norm. speed  Norm. torque     Time   Norm. speed  Norm. torque     Time  Norm. speed  Norm. torque
      per cent     per cent         s      per cent     per cent         s     per cent     per cent