{
  "url": "https://openlegislation.uk/eu-regulation-2017-654/annex-VIII/appendix-2",
  "json_url": "https://openlegislation.uk/eu-regulation-2017-654/annex-VIII/appendix-2.json",
  "legislation": "eur/2017/654",
  "legislation_title": "Commission Delegated Regulation (EU) 2017/654 of 19 December 2016 supplementing Regulation (EU) 2016/1628 of the European Parliament and of the Council with regard to technical and general requirements relating to emission limits and type-approval for internal combustion engines for non-road mobile machinery",
  "legislation_url": "https://openlegislation.uk/eu-regulation-2017-654",
  "path": "annex/VIII/appendix/2",
  "kind": "appendix",
  "number": "2",
  "heading": null,
  "text": "Emission test procedure requirements for dual-fuel engines\n1.\nGeneral\nThis point defines the additional requirements and exceptions of this Annex to enable emission testing of dual-fuel engines independent whether these emissions are solely exhaust emissions or also crankcase emissions added to the exhaust emissions according to point 6.10 of Annex VI. In the case that no additional requirement or exception is listed, the requirements of this Regulation shall apply to dual-fuel engines in the same way as they apply to any other approved engine types or engine families under Regulation (EU) 2016/1628.\nEmission testing of a dual-fuel engine is complicated by the fact that the fuel used by the engine can vary between pure liquid fuel and a combination of mainly gaseous fuel with only a small amount of liquid 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.\n2.\nTest conditions\nSection 6 of Annex VI shall apply.\n3.\nTest procedures\nSection 7 of Annex VI shall apply.\n4.\nMeasurement procedures\nSection 8 of Annex VI shall apply except as set out in this Appendix.\nA full-flow dilution measurement procedure for dual-fuel engines is illustrated in Figure 6.6 of Annex VI (CVS system).\nThis measurement procedure ensures that the variation of the fuel composition during the test will mainly influence the hydrocarbon measurement results. This shall be compensated via one of the methods described in point 7.\nRaw gaseous/partial flow measurement illustrated in Figure 6.7 of Annex VI may be used with some precautions regarding exhaust gas mass flow determination and calculation methods.\n5.\nMeasurement equipment\nSection 9 of Annex VI shall apply.\n6.\nParticle number emissions measurement\nAppendix 1 of Annex VI shall apply.\n7.\nEmission calculation\nThe emission calculation shall be performed according to Annex VII except as set out in this section. The additional requirements set out in point 7.1 shall apply for mass-based calculations and the additional requirements set out in point 7.2 shall apply for molar-based calculations.\nThe emission calculation requires knowledge of the composition of the fuels being used. When a gaseous fuel is supplied with a certificate confirming the properties of the fuel (e.g. gas from bottles) it is acceptable to use the composition specified by the supplier. Where the composition is not available (e.g. pipeline fuel) the fuel composition shall be analysed at least prior to and after the engine emission test is conducted. More frequent analysis shall be permitted and the results used in the calculation.\nWhere the gas energy ratio (GER) is used it shall be consistent with the definition in Article 3(2) of Regulation (EU) 2016/1628 and the specific provisions on total hydrocarbon (HC) limits for fully and partially gaseous-fuelled engines in Annex II of that Regulation. The average value of GER over the cycle shall be calculated by one of the following methods:\n(a) For hot-start NRTC and RMC NRSC by dividing the sum of the GER at each measurement point by the number of measurement points;\n(b) For discrete-mode NRSC by multiplying the average GER for each test mode by the corresponding weighting factor for that mode and calculating the sum for all modes. The weighting factors shall be taken from Appendix 1 of Annex XVII for the applicable cycle.\n7.1.\nMass-based emission calculation\nSection 2 of Annex VII shall apply except as set out in this section.\n7.1.1.\nDry/wet correction\n7.1.1.1.\nRaw exhaust gas\nEquations (7-3) and (7-4) of Annex VII shall be used to calculate the dry/wet correction.\nThe fuel specific parameters shall be determined in accordance with point 7.1.5.\n7.1.1.2.\nDiluted exhaust gas\nEquation (7-3) with either equation (7-25) or (7-26) of Annex VII shall be used to calculate the wet/dry correction.\nThe molar hydrogen ratio α of the combination of the two fuels shall be used for the dry/wet correction. This molar hydrogen ratio shall be calculated from the fuel consumption measurement values of both fuels in accordance with point 7.1.5.\n7.1.2.\nNOx correction for humidity\nThe NOx humidity correction for compression ignition engines as specified in equation (7-9) of Annex VII shall be used.\n7.1.3.\nPartial flow dilution (PFS) and raw gaseous measurement\n7.1.3.1.\nDetermination of exhaust gas mass flow\nThe exhaust gas mass flow shall be determined using a raw exhaust flow meter as described in point 9.4.5.3 of Annex VI.\nAlternatively the airflow and air to fuel ratio measurement method according to equations (7-17) to (7-19) of Annex VII may be used only if α, γ, δ and ε values are determined according to point 7.1.5.3. The use of a zirconia-type sensor to determine the air fuel ratio is not allowed.\nIn the case of testing engines subject to steady-state test cycles only the exhaust gas mass flow may be determined by the air and fuel measurement method in accordance with equation (7-15) of Annex VII.\n7.1.3.2.\nDetermination of the gaseous components\nPoint 2.1 of Annex VII shall apply except as set out in this section.\nThe possible variation of fuel composition will influence all the ugas factors and molar component ratios used in the emission calculations. One of the following approaches shall be used to determine ugas factors and molar component ratios at the choice of the manufacturer.\n(a) The exact equations in point 2.1.5.2 or 2.2.3 of Annex VII shall be applied to calculate instantaneous values of ugas using the instantaneous proportions of liquid and gaseous fuel (determined from instantaneous fuel consumption measurements or calculations) and instantaneous molar component ratios determined in accordance with point 7.1.5; or,\n(b) When the mass-based calculation in section 2 of Annex VII is used for the specific case of a dual-fuel engine operated on gas and diesel fuel, tabulated values may be used for the molar component ratios and ugas values. These tabulated values shall be applied as follows:\n(i) For engines operated on the applicable test cycle with an average gas energy ratio greater than or equal to 90 % (GER ≥ 0,9) the required values shall be those for the gaseous fuel taken from Tables 7.1 or 7.2 of Annex VII.\n(ii) For engines operated on the applicable test cycle with an average gas energy ratio between 10 % and 90 % (0,1 < GER < 0,9) the required values shall be assumed to be represented by those for a mixture of 50 % gaseous fuel and 50 % diesel fuel taken from Tables 8.1 and 8.2.\n(iii) For engines operated on the applicable test cycle with an average gas energy ratio less than or equal to 10 % (GER ≤ 0,1) the required values shall be those for diesel fuel taken from taken from Tables 7.1 or 7.2 of Annex VII.\n(iv) For the calculation of HC emissions the ugas value of the gaseous fuel shall be used in all cases irrespective of the average gas energy ratio (GER).\nTable 8.1\nMolar component ratios for a mixture of 50 % gaseous fuel and 50 % diesel fuel (mass %)\nGaseous fuel\nα\nγ\nδ\nε\nCH4\n2,8681\n0\n0\n0,0040\nGR\n2,7676\n0\n0\n0,0040\nG23\n2,7986\n0\n0,0703\n0,0043\nG25\n2,7377\n0\n0,1319\n0,0045\nPropane\n2,2633\n0\n0\n0,0039\nButane\n2,1837\n0\n0\n0,0038\nLPG\n2,1957\n0\n0\n0,0038\nLPG Fuel A\n2,1740\n0\n0\n0,0038\nLPG Fuel B\n2,2402\n0\n0\n0,0039\n7.1.3.2.1.\nMass per test of a gaseous emission\nIn the case that the exact equations are applied to calculate instantaneous values of u gas in accordance with paragraph 7.1.3.2(a) then, when calculating the mass per test of a gaseous emission for transient (NRTC and LSI-NRTC) test cycles and RMC, u gas shall be included in the summation in equation (7-2) of point 2.1.2 of Annex VII by means of equation (8-1):\nm gas = 1 f × k h × k × ∑ N i = 1 u gas, i × q mew, i × c gas, i\n(8-1)\nWhere:\nu gas, i is the instantaneous value of ugas\nThe remaining terms of the equation are as set out in point 2.1.2 of Annex VII.\nTable 8.2\nRaw exhaust gas u gas values and component densities for a mixture of 50 % gaseous fuel and 50 % diesel fuel (mass %)\nDepending on fuel.\nAt λ = 2, dry air, 273 K, 101,3 kPa.\nu accurate within 0,2 % for mass composition of: C = 58 – 76 %; H = 19 – 25 %; N = 0 – 14 % (CH4, G20, G23, and G25).\nNMHC on the basis of CH2,93 (for total HC the u gas coefficient of CH4 shall be used).\nu accurate within 0,2 % for mass composition of: C3 = 27 – 90 %; C4 = 10 – 73 % (LPG Fuels A and B)\nGaseous fuel\nGas\nρ e\nNOx\nCO\nHC\nCO2\nO2\nCH4\nρ gas [kg/m 3 ]\n2,053\n1,250\n1,9636\n1,4277\n0,716\nu gas\nCNG/LNG\n1,2786\n0,001606\n0,000978\n0,000528\n0,001536\n0,001117\n0,000560\nPropane\n1,2869\n0,001596\n0,000972\n0,000510\n0,001527\n0,001110\n0,000556\nButane\n1,2883\n0,001594\n0,000971\n0,000503\n0,001525\n0,001109\n0,000556\nLPG\n1,2881\n0,001594\n0,000971\n0,000506\n0,001525\n0,001109\n0,000556\n7.1.3.3.\nParticulate determination\nFor the determination of particulate emissions with the partial dilution measurement method the calculation shall be performed according to the equations in point 2.3 of Annex VII.\nThe requirements of point 8.2.1.2 of Annex VI shall apply for controlling the dilution ratio. In particular, if the combined transformation time of the exhaust gas flow measurement and the partial flow system exceeds 0,3 s, look-ahead control based on a pre-recorded test run shall be used. In this case, the combined rise time shall be ≤ 1 s and the combined delay time ≤ 10 s. Except in the case that the exhaust gas mass flow is measured directly the determination of exhaust gas mass flow shall use values of α, γ, δ and ε determined in accordance with point 7.1.5.3.\nThe quality check according to point 8.2.1.2 of Annex VI shall be performed for each measurement.\n7.1.3.4.\nAdditional requirements regarding the exhaust gas mass flow meter\nThe flow meter referred to in points 9.4.5.3 and 9.4.5.4 of Annex VI shall not be sensitive to the changes in exhaust gas composition and density. The small errors of e.g. pitot tube or orifice-type of measurement (equivalent with the square root of the exhaust gas density) may be neglected.\n7.1.4.\nFull flow dilution measurement (CVS)\nPoint 2.2 of Annex VII shall apply except as set out in this section.\nThe possible variation of the fuel composition will mainly influence the tabulated hydrocarbon ugas value. The exact equations shall be applied for the calculation of the hydrocarbon emissions using the molar component ratios determined from the fuel consumption measurements of both fuels according to point 7.1.5.\n7.1.4.1.\nDetermination of the background corrected concentrations\nTo determine the stoichiometric factor, the molar hydrogen ratio α of the fuel shall be calculated as the average molar hydrogen ratio of the fuel mix during the test according to point 7.1.5.3.\nAlternatively the Fs value of the gaseous fuel may be used in equation (7-28) of Annex VII.\n7.1.5.\nDetermination of molar component ratios\n7.1.5.1.\nGeneral\nThis section shall be used for the determination of molar component ratios when the fuel mix is known (exact method).\n7.1.5.2.\nCalculation of the fuel mixture components\nEquations (8-2) to (8-7) shall be used to calculate the elemental composition of the fuel mixture:\nq mf = q mf1 + q mf2\n(8-2)\nw H = w H1 × q m f1 + w H2 × q m f2 q m f1 + q m f2\n(8-3)\nw C = w C1 × q m f1 + w C2 × q m f2 q m f1 + q m f2\n(8-4)\nw S = w S1 × q m f1 + w S2 × q m f2 q m f1 + q m f2\n(8-5)\nw N = w N1 × q m f1 + w N2 × q m f2 q m f1 + q m f2\n(8-6)\nw O = w O1 × q m f1 + w O2 × q m f2 q m f1 + q m f2\n(8-7)\nwhere:\nq m f1 is the fuel mass flow rate of fuel 1 [kg/s]\nq m f2 is the fuel mass flow rate of fuel 2 [kg/s]\nw H is the hydrogen content of fuel [% mass]\nw C is the carbon content of fuel [% mass]\nw S is the sulphur content of fuel [% mass]\nw N is the nitrogen content of fuel [% mass]\nw O is the oxygen content of fuel [% mass]\n7.1.5.3.\nCalculation of the molar ratios of H, C, S, N and O related to C for the fuel mixture\nThe calculation of the atomic ratios (especially the H/C-ratio α) is given in Annex VII by means of equations (8-8) to (8-11):\nα = 11,9164 × w H w C\n(8-8)\nγ = 0,37464 × w S w C\n(8-9)\nδ = 0,85752 × w N w C\n(8-10)\nε = 0,75072 × w O w C\n(8-11)\nwhere:\nw H is the hydrogen content of fuel, mass fraction [g/g] or [% mass]\nw C is the carbon content of fuel, mass fraction [g/g] or [% mass]\nw S is the sulphur content of fuel, mass fraction [g/g] or [% mass]\nw N is the nitrogen content of fuel, mass fraction [g/g] or [% mass]\nw O is the oxygen content of fuel, mass fraction [g/g] or [% mass]\nα is the molar hydrogen ratio (H/C)\nγ is the molar sulphur ratio (S/C)\nδ is the molar nitrogen ratio (N/C)\nε is the molar oxygen ratio (O/C)\nreferring to a fuel CΗ αΟεΝδ S γ\n7.2.\nMolar-based emission calculation\nAnnex VII section 3 shall apply except as set out in this section.\n7.2.1.\nNOx correction for humidity\nEquation (7-102) of Annex VII (correction for compression ignition engines) shall be used.\n7.2.2.\nDetermination of exhaust gas mass flow when not using a raw exhaust flow meter\nEquation (7-112) of Annex VII (molar flow rate calculation based on intake air) shall be used. Equation (7-113) of Annex VII (molar flow rate calculation based on fuel mass flow rate) may alternatively be used only when conducting an NRSC test.\n7.2.3.\nMolar component ratios for determination of the gaseous components\nThe exact approach shall be used to determine the molar component ratios using the instantaneous proportions of liquid and gaseous fuel determined from instantaneous fuel consumption measurements or calculations. The instantaneous molar component ratios shall be input in the equations (7-88), (7-90), and (7-91) of Annex VII for the continuous chemical balance.\nThe determination of the ratios shall be either performed according to point 7.2.3.1 or point 7.1.5.3.\nGaseous fuels, either blended or sourced from a land line, may contain significant amounts of inert constituents such as CO2 and N2. The manufacturer shall either include these constituents in the atomic ratio calculations described in point 7.2.3.1 or point 7.1.5.3 as applicable, or, alternatively, the manufacturer shall exclude the inert constituents from the atomic ratios and allocate them appropriately to the chemical balance intake air parameters x O2int, x CO2int, and x H2Oint in point 3.4.3 of Annex VII.\n7.2.3.1.\nDetermination of molar component ratios\nInstantaneous molar component ratios of the number of hydrogen, oxygen, sulphur, and nitrogen atoms to carbons atoms in the mixed fuel for the dual-fuel engines may be calculated by means of equations (8-12) to (8-15):\nα t = ṁ liquid t × w H,liquid M H + ṁ gas t × w H,gas M H ṁ liquid t × w C,liquid M C + ṁ gas t × w C,gas M C = M C × ṁ liquid t × w H,liquid + ṁ gas t × w H,gas M H × ṁ liquid t × w C,liquid + ṁ gas t × w C,gas\n(8-12)\nβ t = ṁ liquid t × w O,liquid M O + ṁ gas t × w O,gas M O ṁ liquid t × w C,liquid M C + ṁ gas t × w C,gas M C = M C × ṁ liquid t × w O,liquid + ṁ gas t × w O,gas M O × ṁ liquid t × w C,liquid + ṁ gas t × w C,gas\n(8-13)\nγ t = ṁ liquid t × w S,liquid M S + ṁ gas t × w S,gas M S ṁ liquid t × w C,liquid M C + ṁ gas t × w C,gas M C = M C × ṁ liquid t × w S,liquid + ṁ gas t × w S,gas M S × ṁ liquid t × w C,liquid + ṁ gas t × w C,gas\n(8-14)\nδ t = ṁ liquid t × w N,liquid M N + ṁ gas t × w N,gas M N ṁ liquid t × w C,liquid M C + ṁ gas t × w C,gas M C = M C × ṁ liquid t × w N,liquid + ṁ gas t × w N,gas M N × ṁ liquid t × w C,liquid + ṁ gas t × w C,gas\n(8-15)\nWhere:\nw i, fuel the mass fraction of the element of interest, C, H, O, S, or N, of liquid or gaseous fuel;\nṁliquid (t) the instantaneous mass flow rate of the liquid fuel at time t, [kg/hr];\nṁgas (t) the instantaneous mass flow rate of the gaseous fuel at time t, [kg/hr];\nIn cases where exhaust gas mass flow rate is calculated based on the mixed fuel rate then w C in equation (7-113) of Annex VII shall be calculated by means of equation (8-16):\nw C = ṁ liquid × w C,liquid + ṁ gas × w C,gas ṁ liquid + ṁ gas\n(8-16)\nWhere:\nw C the mass fraction of the carbon in the diesel or gaseous fuel;\nṁliquid the mass flow rate of the liquid fuel, [kg/hr];\nṁgas the mass flow rate of the gaseous fuel, [kg/hr].\n7.3.\nCO2 determination\nAnnex VII shall apply except when the engine is tested on transient (NRTC and LSI-NRTC) test cycles or RMC using raw gas sampling.\n7.3.1\nCO2 determination when testing on transient (NRTC and LSI-NRTC) test cycles or RMC using raw gas sampling\nCalculation of CO2 emissions from measurement of CO2 in the exhaust gas in accordance with Annex VII shall not apply. Instead the following provisions shall apply:\nThe measured test-averaged fuel consumption shall be determined from the sum of the instantaneous values over the cycle and shall be used as the base for calculating the test averaged CO2 emissions.\nThe mass of each fuel consumed shall be used to determine, in accordance with section 7.1.5, the molar hydrogen ratio and the mass fractions of the fuel mix in the test.\nThe total corrected fuel mass of both fuels m fuel,corr [g/test] and CO2 mass emission coming from the fuel m CO2, fuel [g/test] shall be determined by means of equations (8-17) and (8-18).\nm fuel,corr = m fuel − m THC + A C + a × A H M CO xm CO + W GAM + W DEL + W EPS 100 × m fuel\n(8-17)\nm CO 2 fuel = M CO 2 A C + a + A H × m fuel,corr\n(8-18)\nWhere:\nm fuel total fuel mass of both fuels [g/test]\nm THC mass of total hydrocarbon emissions in the exhaust gas [g/test]\nm CO mass of carbon monoxide emissions in the exhaust gas [g/test]\nw GAM sulphur content of the fuels [per cent mass]\nw DEL nitrogen content of the fuels [per cent mass]\nw EPS is the oxygen content of the fuels [per cent mass]\nα is the molar hydrogen ratio of the fuels (H/C) [-]\nA C is the atomic mass of Carbon: 12,011 [g/mol]\nA H is the atomic mass of Hydrogen: 1,0079 [g/mol]\nM CO is the molecular mass of Carbon monoxide: 28,011 [g/mol]\nM CO2 is the molecular mass of Carbon dioxide: 44,01 [g/mol]\nThe CO2 emission resulting from urea m CO2,urea [g/test] shall be calculated by means of equation (8-19):\nm CO 2 ,urea = c urea 100 × M CO2 M CO NH 2 2 × m urea\n(8-19)\nWhere:\nc urea urea concentration [per cent]\nm urea total urea mass consumption [g/test]\nM CO(NH2)2 Molecular mass of urea: 60,056 [g/mol]\nThen the total CO2 emission m CO2 [g/test] shall be calculated by means of equation (8-20):\nmCO2 = mCO2,fuel + mCO2,urea\n(8-20)\nThe total CO2 emission calculated by means of equation (8-20) shall be used in the calculation of brake specific CO2 emissions, eCO2 [g/kWh] in section 2.4.1.1 or 3.8.1.1 of Annex VII. Where applicable, the correction for CO2 in the exhaust gas arising from CO2 in the gaseous fuel shall be performed in accordance with Appendix 3 to Annex IX.",
  "extent": "E+W+S+N.I.",
  "status": null,
  "version": "current",
  "annotations": [
    {
      "type": "F",
      "label": "F1",
      "text": "Substituted by Commission Delegated Regulation (EU) 2018/989 of 18 May 2018 amending and correcting Delegated Regulation (EU) 2017/654 supplementing Regulation (EU) 2016/1628 of the European Parliament and of the Council with regard to technical and general requirements relating to emission limits and type-approval for internal combustion engines for non-road mobile machinery (Text with EEA relevance)."
    },
    {
      "type": "F",
      "label": "F2",
      "text": "Inserted by Commission Delegated Regulation (EU) 2018/989 of 18 May 2018 amending and correcting Delegated Regulation (EU) 2017/654 supplementing Regulation (EU) 2016/1628 of the European Parliament and of the Council with regard to technical and general requirements relating to emission limits and type-approval for internal combustion engines for non-road mobile machinery (Text with EEA relevance)."
    },
    {
      "type": "footnote",
      "label": "f1",
      "text": "Depending on fuel."
    },
    {
      "type": "footnote",
      "label": "f2",
      "text": "At λ = 2, dry air, 273 K, 101,3 kPa."
    },
    {
      "type": "footnote",
      "label": "f3",
      "text": "u accurate within 0,2 % for mass composition of: C = 58 – 76 %; H = 19 – 25 %; N = 0 – 14 % (CH4, G20, G23, and G25)."
    },
    {
      "type": "footnote",
      "label": "f4",
      "text": "NMHC on the basis of CH2,93 (for total HC the u gas coefficient of CH4 shall be used)."
    },
    {
      "type": "footnote",
      "label": "f5",
      "text": "u accurate within 0,2 % for mass composition of: C3 = 27 – 90 %; C4 = 10 – 73 % (LPG Fuels A and B)"
    }
  ],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/eur/2017/654/annex/VIII/appendix/2",
    "retrieved_at": "2026-11-01T14:45:01.864924+00:00"
  },
  "licence": "Open Government Licence v3.0",
  "licence_url": "https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/",
  "attribution": "Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives."
}