{
  "url": "https://openlegislation.uk/eu-regulation-2017-654/annex-I/division-2/division-2.3/division-2.3.1/division-2.3.1.1",
  "json_url": "https://openlegislation.uk/eu-regulation-2017-654/annex-I/division-2/division-2.3/division-2.3.1/division-2.3.1.1.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/I/division/2/division/2.3/division/2.3.1/division/2.3.1.1",
  "kind": "division",
  "number": "2.3.1.1",
  "heading": null,
  "text": "For engines fuelled with compressed natural gas/biomethane (CNG) there are generally two types of fuel, high calorific fuel (H-gas) and low calorific fuel (L-gas), but with a significant spread within both ranges; they differ significantly in their energy content expressed by the Wobbe Index and in their λ-shift factor (Sλ). Natural gases with a λ-shift factor between 0,89 and 1,08 (0,89 ≤ Sλ ≤ 1,08) are considered to belong to H-range, while natural gases with a λ-shift factor between 1,08 and 1,19 (1,08 ≤ Sλ ≤ 1,19) are considered to belong to L-range. The composition of the reference fuels reflects the extreme variations of Sλ.\nThe parent engine shall meet the requirements of this Regulation on the reference fuels GR (fuel 1) and G25 (fuel 2), as specified in Annex IX, or on the equivalent fuels created using admixtures of pipeline gas with other gases as specified in Appendix 1 of Annex IX, without any manual readjustment to the engine fuelling system between the two tests (self-adaptation is required). One adaptation run is permitted after the change of the fuel. The adaption run shall consist of performing the pre-conditioning for the following emission test according to the respective test cycle. In the case of engines tested on the non-road steady-state test cycles (‘NRSC’), where the pre-conditioning cycle is inadequate for the engine fuelling to self-adapt an alternative adaption run specified by the manufacturer may be performed prior to pre-conditioning the engine.",
  "extent": "E+W+S+N.I.",
  "status": null,
  "version": "current",
  "annotations": [],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/eur/2017/654/annex/I/division/2/division/2.3/division/2.3.1/division/2.3.1.1",
    "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."
}