Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:20:p21
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 20 (pt 21/29)
Character Range: 276545–279480

shall be measured and the parameter fa shall be determined according to the following provisions. In multi-cylinder engines having distinct groups of intake manifolds, such as in a "Vee" engine configuration, the average temperature of the distinct groups shall be taken. The parameter fa shall be reported with the test results. For better repeatability and reproducibility of the test results, it is recommended that the parameter fa be such that: 0.93    fa    1.07.
              (a) Compression-ignition engines:
   Naturally aspirated and mechanically supercharged engines:
  (1)
 Turbocharged engines with or without cooling of the intake air:
  (2)
(b) Positive ignition engines:
  (3)
6.2. Engines with charge air-cooling
 The charge air temperature shall be recorded and shall be, at the rated speed and full load, within 5 K of the maximum charge air temperature specified by the manufacturer. The temperature of the cooling medium shall be at least 293 K (20 °C).
 If a test laboratory system or external blower is used, the coolant flow rate shall be set to achieve a charge air temperature within 5 K of the maximum charge air temperature specified by the manufacturer at the rated speed and full load. Coolant temperature and coolant flow rate of the charge air cooler at the above set point shall not be changed for the whole test cycle, unless this results in unrepresentative overcooling of the charge air. The charge air cooler volume shall be based upon good engineering practice and shall be representative of the production engine's in-use installation. The laboratory system shall be designed to minimize accumulation of condensate. Any accumulated condensate shall be drained and all drains shall be completely closed before emission testing.
 If the engine manufacturer specifies pressure-drop limits across the charge-air cooling system, it shall be ensured that the pressure drop across the charge-air cooling system at engine conditions specified by the manufacturer is within the manufacturer's specified limit(s). The pressure drop shall be measured at the manufacturer's specified locations.
6.3. Engine power
 The basis of specific emissions measurement is engine power and cycle work as determined in accordance with paragraphs 6.3.1. to 6.3.5.
6.3.1. General engine installation
 The engine shall be tested with the auxiliaries/equipment listed in Appendix 6.
 If auxiliaries/equipment are not installed as required, their power shall be taken into account in accordance with paragraphs 6.3.2. to 6.3.5.
       6.3.2.  Auxiliaries/equipment to be fitted for the emissions test
 If it is inappropriate to install the auxiliaries/equipment required according to Appendix 6 to this annex on the test bench, the power absorbed by them shall be determined and subtracted from the measured engine power (reference and actual) over the whole engine speed range of the WHTC and over the test speeds of the