Document ID: chunk:federal_register_of_legislation:F2023C00229:reg:9:p22
Version: federal_register_of_legislation:F2023C00229
Segment Type: reg
Provision Reference: reg 9 (pt 22/71)
Character Range: 270689–273757

as to maintain a gas temperature of 463K ± 10K (190 ± 10 °C). For NG fuelled gas engines, the hydrocarbon analyser may be of the non- heated Flame Ionisation Detector (FID) type depending upon the method used (see Annex V, Section 1.3).

3.3.4.                        Non-methane hydrocarbon (NMHC) analysis (NG fuelled gas engines only)

              Non-methane hydrocarbons shall be determined by either of the following methods:

3.3.4.1.                    Gas chromatographic (GC) method

              Non-methane hydrocarbons shall be determined by subtraction of the methane analysed with a Gas Chromatograph (GC) conditioned at 423 K (150 °C) from the hydrocarbons measured according to Section 3.3.3.

3.3.4.2.                    Non-methane cutter (NMC) method

              The determination of the non-methane fraction shall be performed with a heated NMC operated in line with an FID as per Section 3.3.3 by subtraction of the methane from the hydrocarbons.

3.3.5.                        Oxides of nitrogen (NOx) analysis

              The oxides of nitrogen analyser shall be of the ChemiLuminescent Detector (CLD) or Heated ChemiLuminescent Detector (HCLD) type with a NO2/NO converter, if measured on a dry  basis.  If measured on a wet basis, a HCLD with converter maintained above 328 K (55 °C) shall be used, provided   the water quench check (see Annex III, Appendix 5, Section 1.9.2.2) is satisfied.

3.4.                            Sampling of gaseous emissions

3.4.1.                        Raw exhaust gas (ESC only)

              The gaseous emissions sampling probes must be fitted at least 0,5 m or 3 times the diameter of the exhaust pipe whichever is the larger-upstream of the exit of the exhaust gas system as far as applicable and sufficiently close to the engine as to ensure an exhaust gas temperature of at least 343 K (70 °C) at the probe.

              In the case of a multi-cylinder engine with a branched exhaust manifold, the inlet of the probe shall be located sufficiently far downstream so as to ensure that the sample is representative of the average exhaust emissions from all cylinders. In multi-cylinder engines having distinct groups of manifolds, such as in a 'Vee' engine configuration, it is permissible to acquire a sample from each group individually and calculate an average exhaust emission. Other methods which have been shown to correlate with the above methods may be used. For exhaust emission calculation the total exhaust mass flow must be used.

              If the engine is equipped with an exhaust aftertreatment system, the exhaust sample shall be taken downstream of the exhaust aftertreatment system.

3.4.2.                        Diluted exhaust gas (mandatory for ETC, optional for ESC)

              The exhaust pipe between the engine and the full flow dilution system shall conform to the requirements of Annex V, Section 2.3.1, EP.

              The gaseous emissions sample probe(s) shall be installed in the dilution tunnel at a point where the dilution air and exhaust gas are