{
  "url": "https://openlegislation.uk/eu-regulation-2017-654/annex-VII/division-3/division-3.6/division-3.6.3",
  "json_url": "https://openlegislation.uk/eu-regulation-2017-654/annex-VII/division-3/division-3.6/division-3.6.3.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/VII/division/3/division/3.6/division/3.6.3",
  "kind": "division",
  "number": "3.6.3",
  "heading": "Exhaust gas molar flow rate",
  "text": "(a) Calculation via chemical balance;\nThe molar flow rate ṅ exh [mol/s] can be calculated based on fuel mass flow rate ṁ fuel by means of equation (7-113):\nṅ exh = ṁ fuel × w C × 1 + x H2Oexhdry M C × x Ccombdry\n(see equation 7-113)\nWhere:\nṅ exh raw exhaust gas molar flow rate from which emissions are measured\nṁ fuel fuel flow rate including humidity in intake air [g/s]\nw C carbon mass fraction for the given fuel [g/g]\nx H2Oexhdry amount of H2O per dry mole of measured flow [mol/mol]\nM C molecular mass of carbon 12,0107 g/mol\nx Ccombdry amount of carbon from fuel in the exhaust gas per mole of dry exhaust gas [mol/mol]\n(b) Measurement\nThe exhaust gas molar flow rate may be measured by means of three systems:\n(i) PDP molar flow rate. Based upon the speed at which the Positive Displacement Pump (PDP) operates for a test interval, the corresponding slope a 1 , and intercept, a 0 [-], as calculated with the calibration procedure set out in point 3.9.2, shall be used to calculate molar flow rate ṅ [mol/s] by means of equation (7-117):\nṅ = ƒ n,PDP × p in × V rev R × T in\n(7-117)\nwith:\nV rev = a 1 f n,PDP × p out − p in p in + a 0\n(7-118)\nwhere:\na 1 calibration coefficient [m3/s]\na 0 calibration coefficient [m3/rev]\np in, p out inlet/outlet pressure [Pa]\nR molar gas constant [J/(mol · K)]\nT in inlet temperature [K]\nV rev PDP pumped volume [m3/rev]\nf n.,PDP PDP speed [rev/s]\n(ii) SSV molar flow rate. Based on the C d versus R e # equation determined in accordance with point 3.9.4, the Sub-Sonic Venturi (SSV) molar flow rate during an emission test ṅ [mol/s] shall be calculated by means of equation (7-119):\nṅ = C d × C f × A t × p in Z × M mix × R × T in\n(7-119)\nWhere:\np in inlet pressure [Pa]\nA t Venturi throat cross-sectional area [m2]\nR molar gas constant [J/(mol · K)]\nT in inlet temperature [K]\nZ compressibility factor\nM mix molar mass of diluted exhaust gas [kg/mol]\nC d discharge coefficient of the SSV [-]\nC f flow coefficient of the SSV [-]\n(iii) CFV molar flow rate. To calculate the molar flow rate through one venturi or one combination of venturis, its respective mean C d and other constants, determined in accordance with point 3.9.5, shall be used. The calculation of its molar flow rate ṅ [mol/s] during an emission test shall be calculated by means of equation (7-120):\nṅ = C d × C f × A t × p in Z × M mix × R × T in\n(7-120)\nWhere:\np in inlet pressure [Pa]\nA t Venturi throat cross-sectional area [m2]\nR molar gas constant [J/(mol · K)]\nT in inlet temperature [K]\nZ compressibility factor\nM mix molar mass of diluted exhaust gas [kg/mol]\nC d discharge coefficient of the CFV [-]\nC f flow coefficient of the CFV [-]",
  "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)."
    }
  ],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/eur/2017/654/annex/VII/division/3/division/3.6/division/3.6.3",
    "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."
}