Document ID: chunk:federal_register_of_legislation:F2024L00447:reg:0:p41
Version: federal_register_of_legislation:F2024L00447
Segment Type: reg
Provision Reference: reg 0 (pt 41/57)
Character Range: 204592–207577

exhaust mass flow rate are determined from ECU recording, the calculated instantaneous exhaust mass flow rate shall meet the linearity requirements specified for the exhaust mass flow rate in paragraph 3. of Annex 5 and the validation requirements specified in paragraph 4.3. of Annex 6.

       7.3. Calculation method using air mass flow and air-to-fuel ratio

The instantaneous exhaust mass flow rate can be calculated from the air mass flow rate and the air-to-fuel ratio as follows:

              where:

              where:

qmaw,i  is the instantaneous intake air mass flow rate [kg/s]

A/Fst   is the stoichiometric air-to-fuel ratio [kg/kg]

λi      is the instantaneous excess air ratio

cCO2    is the dry CO2 concentration [%]

cCO     is the dry CO concentration [ppm]

cHCw    is the wet HC concentration [ppm]

α       is the molar hydrogen ratio (H/C)

β       is the molar carbon ratio (C/C)

γ       is the molar sulphur ratio (S/C)

δ       is the molar nitrogen ratio (N/C)

ε       is the molar oxygen ratio (O/C)

Coefficients refer to a fuel Cβ Hα Oε Nδ Sγ with β = 1 for carbon based fuels. The concentration of HC emissions is typically low and may be omitted when calculating λi.
If the air mass flow rate and air-to-fuel ratio are determined from ECU recording, the calculated instantaneous exhaust mass flow rate shall meet the linearity requirements specified for the exhaust mass flow rate in paragraph 3. of Annex 5 and the validation requirements specified in paragraph 4.3. of Annex 6.

       7.4. Calculation method using fuel mass flow and air-to-fuel ratio

The instantaneous exhaust mass flow rate can be calculated from the fuel flow and the air-to-fuel ratio (calculated with A/Fst and λi according to paragraph 7.3.) as follows:
The calculated instantaneous exhaust mass flow rate shall meet the linearity requirements specified for the exhaust gas mass flow rate in paragraph 3. of Annex 5 and the validation requirements specified in paragraph 4.3. of Annex 6.

       8. Calculating the instantaneous mass emissions of gaseous components

              The instantaneous mass emissions [g/s] shall be determined by multiplying the instantaneous concentration of the pollutant under consideration [ppm] with the instantaneous exhaust mass flow rate [kg/s], both corrected and aligned for the transformation time, and the respective u value in Table A7/1. If measured on a dry basis, the dry-wet correction according to paragraph 5.1. shall be applied to the instantaneous component concentrations before executing any further calculations. If occurring, negative instantaneous emission values shall enter all subsequent data evaluations. Parameter values shall enter the calculation of instantaneous emissions [g/s] as reported by the analyser, flow-measuring instrument, sensor or the ECU. The following equation shall be applied:

              where:
mgas,i  is the mass of the exhaust component 'gas' [g/s]

ugas    is the ratio of the