Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:99:p34
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 99 (pt 34/39)
Character Range: 1249154–1252246

according to section A.6.4. of Appendix 6.

              Alternatively the Fs value of the gaseous fuel may be used in equation 59 or 60 of Annex 4.

              A.4.5. Equipment specification and verification (Annex 4, section 9.)

              A.4.5.1. Oxygen interference check gases (Annex 4, paragraph 9.3.3.4.)

              The oxygen concentrations required for dual-fuel engines are equal to those required for compression ignition engines listed in table 8 in paragraph 9.3.3.4. of Annex 4.

              A.4.5.2. Oxygen interference check (Annex 4, paragraph 9.3.7.3.)

              Instruments used to measure dual-fuel engines shall be checked using the same procedures as those used to measure compression ignition engines. The 21 per cent oxygen blend shall be used under item (b) in paragraph 9.3.7.3. of Annex 4.

              A.4.5.3. Water quench check (Annex 4, paragraph 9.3.9.2.2.)

              The water quench check in paragraph 9.3.9.2.2. of Annex 4 to this regulation applies to wet NOx concentration measurements only. For dual-fuel engines fuelled with natural gas this check should be performed with an assumed H/C ratio of 4 (Methane). In that case Hm = 2 x A. For dual-fuel engines fuelled with LPG this check should be performed with an assumed H/C ratio of 2.525. In that case Hm = 1.25 x A.

                   Annex 15 - Appendix 5 Additional PEMS emission test procedure requirements for dual-fuel engines
              A.5.1.  General

              This appendix defines the additional requirements and exceptions to Annex 8 of this regulation to enable PEMS emission testing of dual-fuel engines.

              Emission testing of a dual-fuel engine is complicated by the fact that the fuel used by the engine can vary between pure diesel fuel and a combination of mainly gaseous fuel with only a small amount of diesel fuel as an ignition source. The ratio between the fuels used by a dual-fuel engine can also change dynamically depending of the operating condition of the engine. As a result special precautions and restrictions are necessary to enable emission testing of these engines.

              A.5.2. The following amendments to Appendix 1 of Annex 8 shall apply:

              A.5.2.1. Note (2) of Table 1 in paragraph A.1.2.2. shall read:

              (2) Only for engines fuelled with natural gas

              A.5.2.2. Paragraph A.1.3.3. "Dry-Wet correction" shall read:

              If the concentration is measured on a dry basis, it shall be converted to a wet basis according to paragraph 8.1. of Annex 4 and paragraph 4.1.1. of Appendix 4 to this annex.

              A.5.2.3. Paragraph A.1.3.5. "Calculation of the instantaneous gaseous emissions" shall read:

              The mass emissions shall be determined as described in paragraph 8.4.2.3. of Annex 4. The ugas values shall be determined according to sections A.6.2. and A.6.3. of appendix 6 of Annex 15.

                   Annex 15 - Appendix 6 Determination of molar component ratios and ugas values for dual-fuel engines
              A.6.1.  General