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Division 5.4 Correction factor for engines equipped with exhaust after-treatment systems that are regenerated on a periodic basis

United Kingdom

Original text. Later amendments are not shown.

For engines equipped with exhaust after-treatment systems that are regenerated on a periodic basis defined in accordance with paragraph 6.6.1 of Annex 4 to UN/ECE Regulation 49 Rev.06, fuel consumption shall be adjusted to account for regeneration events by a correction factor.

This correction factor, CFRegPer, shall be determined in accordance with paragraph 6.6.2 of Annex 4 to UN/ECE Regulation 49 Rev.06.

For engines equipped with exhaust after-treatment systems with continuous regeneration, defined in accordance with paragraph 6.6 of Annex 4 to UN/ECE Regulation 49 Rev.06, no correction factor shall be determined and the value of the factor CFRegPer shall be set to 1.

The engine full load curve recorded in accordance with paragraph 4.3.1 shall be used for the denormalization of the WHTC reference cycle and all calculations of reference values performed in accordance with paragraphs 7.4.6, 7.4.7 and 7.4.8 of Annex 4 to UN/ECE Regulation 49 Rev.06.

In addition to the provisions defined in Annex 4 to UN/ECE Regulation 49 Rev.06 the actual fuel mass flow consumed by the engine in accordance with paragraph 3.4 shall be recorded for each WHTC hot start test performed in accordance with paragraph 6.6.2 of Annex 4 to UN/ECE Regulation 49 Rev.06.

The specific fuel consumption for each WHTC hot start test performed shall be calculated by the following equation:

SFCmeas, m = (Σ FCmeas, m) / (Wact, m)

where:

SFCmeas, m

  • Specific fuel consumption [g/kWh]

    • Σ FCmeas,m

  • Total fuel consumption over the WHTC [g] determined in accordance with paragraph 5.2 of this Annex

    • Wact, m

  • Total engine work over the WHTC [kWh] determined in accordance with paragraph 5.1 of this Annex

    • m

  • Index defining each individual WHTC hot start test

    • The specific fuel consumption values for the individual WHTC tests shall be weighted by the following equation:

    SFC w = n × SFC avg + n r × SFC avg,r n + n r

    where:

    n

  • the number of WHTC hot start tests without regeneration

    • nr

  • the number of WHTC hot start tests with regeneration (minimum number is one test)

    • SFCavg

  • the average specific fuel consumption from all WHTC hot start tests without regeneration [g/kWh]

    • SFCavg,r

  • the average specific fuel consumption from all WHTC hot start tests with regeneration [g/kWh]

    • The correction factor, CFRegPer, shall be calculated by the following equation:

    CF RegPer = SFC w SFC avg