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Division 2.1.3 Dry-to-wet concentration conversion

United Kingdom

Original text. Later amendments are not shown.

If the emissions are measured on a dry basis, the measured concentration c d on dry basis shall be converted to the concentration c w on a wet basis by means of equation (7-3):

c w = k w × c d (7-3)

where:

k w

  • dry-to-wet conversion factor [-]

    • c d

  • emission concentration on a dry basis [ppm] or [% vol]

    • For complete combustion, the dry-to-wet conversion factor for raw exhaust gas is written as k w,a [-] and shall be calculated by means of equation (7-4):

    F1 k w,a = 1 − 1,2442 × H a + 111,19 × w H × q m f, i q m ad, i 773,4 + 1,2442 × H a + q m f, i q m ad, i × k f × 1000 1 − p r p b (7-4)

    where:

    H a

  • intake air humidity [g H2O/kg dry air]

    • qm f, i

  • instantaneous fuel flow rate [kg/s]

    • qm ad, i

  • instantaneous dry intake air flow rate [kg/s]

    • p r

  • water pressure after cooler [kPa]

    • p b

  • total barometric pressure [kPa]

    • w H

  • hydrogen content of the fuel [% mass]

    • k f

  • combustion additional volume [m3/kg fuel]

    • with:

    k f = 0,055594 × w H + 0,0080021 × w N + 0,0070046 × w o (7-5)

    where:

    w H

  • hydrogen content of fuel [% mass]

    • w N

  • nitrogen content of fuel [% mass]

    • w O

  • oxygen content of fuel [% mass]

    • In equation (7-4), the ratio p r/p b may be assumed:

    1 1 − p r p b = 1,008 (7-6)

    For incomplete combustion (rich fuel air mixtures) and also for emission tests without direct air flow measurements, a second method of k w,a calculation is preferred:

    k w,a = 1 1 + α × 0,005 × c CO2 + c CO − K w1 1 − p r p b (7-7)

    where:

    c CO2

  • concentration of CO2 in the raw exhaust gas, on a dry basis [per cent vol]

    • c CO

  • concentration of CO in the raw exhaust gas, on a dry basis [ppm]

    • p r

  • water pressure after cooler [kPa]

    • p b

  • total barometric pressure [kPa]

    • α

  • molar to carbon hydrogen ratio [-]

    • k w1

  • intake air moisture [-]

    • k w1 = 1,608 × H a 1000 + 1,608 × H a (7-8)

    Annotations

    Textual amendments

    F1

    Substituted by Commission Delegated Regulation (EU) 2018/989 of 18 May 2018 amending and correcting Delegated Regulation (EU) 2017/654 supplementing Regulation (EU) 2016/1628 of the European Parliament and of the Council with regard to technical and general requirements relating to emission limits and type-approval for internal combustion engines for non-road mobile machinery (Text with EEA relevance).