Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:99:p35
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 99 (pt 35/39)
Character Range: 1251973–1256101

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

              This appendix defines the determination of molar component ratios and ugas values for the dry-wet factor and emissions calculations for emission testing of dual-fuel engines.

              A.6.2. Operation in dual-fuel mode

              A.6.2.1. For Type 1A or 1B dual-fuel engines operating in dual-fuel mode the molar component ratios and the ugas values of the gaseous fuel shall be used.

              A.6.2.2. For Type 2A or 2B dual-fuel engines operating in dual-fuel mode the molar component ratios and the ugas values from tables A6.1 and A6.2 shall be used.

Table A6.1
Molar component ratios for a mixture of 50% gaseous fuel and 50% diesel fuel (mass %)
Gaseous Fuel  α       γ      δ           ε
 CH4          2.8681      0  0           0.0040
GR            2.7676      0  0           0.0040
G23           2.7986      0      0.0703  0.0043
G25           2.7377      0      0.1319  0.0045
Propane       2.2633  0      0           0.0039
Butane        2.1837  0      0           0.0038
LPG           2.1957  0      0           0.0038
LPG Fuel A    2.1740  0      0           0.0038
LPG Fuel B    2.2402  0      0           0.0039

Table A6.2
Raw exhaust gas ugas values and component densities for a mixture of 50% gaseous fuel and 50% diesel fuel (mass %)
                                                                                                                                e                              Gas
Gaseous Fuel
NOx                                                                                                                             CO      HC            CO2       O2          CH4
                                                                                                                                        gas [kg/m3]
2.053                                                                                                                           1.250   a)            1.9636    1.4277      0.716
                                                                                                                                        ugasb)
CNG/LNGc)                                                                                                                       1.2786  0.001606      0.000978  0.000528d)  0.001536  0.001117  0.000560
Propane                                                                                                                         1.2869  0.001596      0.000972  0.000510    0.001527  0.001110  0.000556
Butane                                                                                                                          1.2883  0.001594      0.000971  0.000503    0.001525  0.001109  0.000556
LPGe)                                                                                                                           1.2881  0.001594      0.000971  0.000506    0.001525  0.001109  0.000556
   a) depending on fuel
   b) at  = 2, dry air, 273 K, 101.3 kPa
   c) u accurate within 0.2 % for mass composition of: C = 58 - 76 %; H = 19 - 25 %; N = 0 - 14 %  (CH4, G20, GR, G23 and G25)
   d) NMHC on the basis of CH2.93 (for total HC the ugas coefficient of CH4 shall be used)
   e) u accurate within 0.2 % for mass composition of: C3 = 27 - 90 %; C4 = 10 - 73 % (LPG Fuels A and B)

A.6.2.3. For Type 3B dual-fuel engines operating in dual-fuel mode the molar component ratios and the ugas values of diesel fuel shall be used.
              A.6.2.4. For the calculation of the hydrocarbon emissions of all types of dual-fuel engines operating in dual-fuel mode, the following shall apply:

                - For the calculation of the THC emissions, the ugas value of the gaseous fuel shall be used.

                - For the calculation of the NMHC emissions, the ugas value on the basis of CH2.93 shall be used.

                -