Document ID: chunk:federal_register_of_legislation:F2023C00229:reg:9:p17
Version: federal_register_of_legislation:F2023C00229
Segment Type: reg
Provision Reference: reg 9 (pt 17/71)
Character Range: 255963–259390

background corrected concentrations over the cycle from
                               integration (mandatory for NOx and HC) or bag measurement, ppm

              MTOTW = total mass of diluted exhaust gas over the cycle as determined in Section 4.1, kg KH,D = humidity correction factor for diesel engines as determined in Section 4.2
              KH,G = humidity correction factor for gas engines as determined in Section 4.2

         (1)     Based on C1 equivalent.

              Concentrations measured on a dry basis shall be converted to a wet basis in accordance with Annex III,

              The determination of NMHCconc depends on the method used (see Annex III, Appendix 4, Section 3.3.4). In both cases, the CH4 concentration shall be determined and subtracted from the HC concentration as follows:

                (a)    GC method

  NMHCconc = HCconc – CH4 conc

                (b)    NMC method

              where:

              HC(wCutter) = HC concentration with the sample gas flowing through the NMC HC(w/oCutter) = HC concentration with the sample gas bypassing the NMC
              CEM = methane efficiency as determined per Annex III, Appendix 5, Section 1.8.4.1 CEE = ethane efficiency as determined per Annex III, Appendix 5, Section 1.8.4.2
4.3.1.1.                    Determination of the background corrected concentrations

              The average background concentration of the gaseous pollutants in the dilution air shall be subtracted from measured concentrations to get the net concentrations of the pollutants. The average values of the background concentrations can be determined by the sample bag method or by continuous measurement with integration. The following formula shall be used.

              where:

                      conc = concentration of the respective pollutant in the diluted exhaust gas, corrected by the amount of the respective pollutant contained in the dilution air, ppm

                      conce = concentration of the respective pollutant measured in the diluted exhaust gas, ppm

                      concd = concentration of the respective pollutant measured in the dilution air, ppm

                      DF = dilution factor

              The dilution factor shall be calculated as follows:

                (a)    for diesel and LPG fuelled gas engines

                (b)    for NG-fuelled gas engines

              where:

              CO2, conce = concentration of CO2 in the diluted exhaust gas, % vol HCconce = concentration of HC in the diluted exhaust gas, ppm C1 NMHCconce = concentration of NMHC in the diluted exhaust gas, ppm C1 COconce              = concentration of CO in the diluted exhaust gas, ppm
              FS = stoichiometric factor

              Concentrations measured on dry basis shall be converted to a wet basis in accordance with Annex III, Appendix 1, Section 4.2.

              The stoichiometric factor shall be calculated as follows:

              where:

              x, y = fuel composition CxHy

              Alternatively, if the fuel composition is not known, the following stoichiometric factors may be used: FS (diesel) = 13,4
              FS (LPG) =   11,6

              FS (NG) = 9,5

4.3.2.                        Systems with flow compensation

              For systems without heat exchanger, the mass of the pollutants (g/test) shall