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Appendix 3

United Kingdom

Original text. Later amendments are not shown.

Correction for CO2 in the exhaust gas arising from CO2 in the gaseous fuel

1.

Instantaneous mass flow rate of CO2 in the gaseous fuel stream

1.1.

Gas composition and gas flow shall be determined according to the requirements of sections 1 to 4 of Appendix 1.

1.2

The instantaneous mass flow rate of CO2 in a stream of gas supplied to the engine shall be calculated by means of equation (9-8).

ṁ CO2i = (M CO2/M stream) · x CO2i · ṁ streami (9-8)

Where:

ṁ CO2i

  • Instantaneous mass flow rate of CO2 from the gas stream [g/s]

    • ṁ streami,

  • Instantaneous mass flow rate of the gas stream [g/s]

    • x CO2i

  • Molar fraction of CO2 in the gaseous stream [-]

    • M CO2

  • Molar mass of CO2 [g/mol]

    • M stream

  • Molar mass of gas stream [g/mol]

    • M stream shall be calculated from all measured constituents (1, 2, …, n) by means of equation (9-9).

    M stream = x 1 · M 1 + x 2 · M 2 + … + x n · M n (9-9)

    Where:

    X 1, 2, … n

  • Molar fraction of each measured constituent in the gas stream (CH4, CO2, …) [-]

    • M 1, 2, … n

  • Molar mass of each measured constituent in the gas stream [g/mol]

    • 1.3.

    In order to determine the total mass flow rate of CO2 in the gaseous fuel entering the engine the calculation in equation (9-8) shall be performed for each individual gas stream containing CO2 that is entering the gas blending system and the result for each gas stream added together, or it shall be performed for the blended gas leaving the blending system and entering the engine by means of equation (9-10):

    ṁ CO2i, fuel = ṁ CO2i, a + ṁ CO2i, b + … + ṁ CO2i, n (9-10)

    Where:

    ṁ CO2i, fuel

  • instantaneous combined mass flow rate of CO2 arising from the CO2 in the gaseous fuel entering the engine [g/s]

    • ṁ CO2i, a, b, …, n

  • instantaneous mass flow rate of CO2 arising from the CO2 in each individual gas stream a, b, …, n [g/s]

    • 2.

    Calculation of specific CO2 emissions for transient (NRTC and LSI-NRTC) test cycles and RMC

    2.1

    The total mass per test of CO2 emission from the CO2 in the fuel m CO2, fuel [g/test] shall be calculated by summation of the instantaneous mass flow rate of CO2 in the gaseous fuel entering the engine ṁ CO2i, fuel [g/s] over the test cycle by means of equation (9-11):

    m CO2,fuel = 1 ƒ × ∑ N i = 1 ṁ CO2,fuel (9-11)

    Where:

    ƒ

  • data sampling rate [Hz]

    • N

  • number of measurements [-]

    • 2.2

    The total mass of CO2 emission m CO2 [g/test] used in equation (7-61), (7-63), (7-128) or (7-130) of Annex VII to calculate the specific emissions result e CO2 [g/kWh] shall be replaced in those equations by the corrected value m CO2, corr [g/test] calculated by means of equation (9-12).

    m CO2, corr = m CO2 – m CO2, fuel (9-12)

    3.

    Calculation of specific CO2 emissions for discrete-mode NRSC

    3.1

    The mean mass flow of CO2 emission from the CO2 in the fuel per hour qm CO2, fuel or ṁ CO2 fuel [g/h] shall be calculated for each individual test mode from the measurements of instantaneous mass flow rate of CO2 ṁ CO2i, fuel [g/s] given by equation (9-10) taken during the sampling period of the respective test mode by means of equation (9-13):

    q m CO2,fuel = ṁ CO2,fuel = 1 3600 × N × ∑ N i = 1 ṁ CO2,fuel (9-13)

    Where:

    N

  • number of measurements taken during the test mode [-]

    • 3.2

    The mean mass flow rate of CO2 emission qm CO2 or ṁ CO2 [g/h] for each individual test mode used in equation (7-64) or (7-131) of Annex VII to calculate the specific emissions result e CO2 [g/kWh] shall be replaced in those equations by the corrected value qm CO2, corr or ṁ CO2, corr [g/h] for each individual test mode calculated by means of equation (9-14) or (9-15).

    q m CO2, corr = q m CO2 – q m CO2, fuel (9-14)
    ṁ CO2, corr = ṁ CO2– ṁ CO2, fuel (9-15)