{
  "url": "https://openlegislation.uk/eu-regulation-2017-654/annex-III/division-4/division-4.3",
  "json_url": "https://openlegislation.uk/eu-regulation-2017-654/annex-III/division-4/division-4.3.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/III/division/4/division/4.3",
  "kind": "division",
  "number": "4.3",
  "heading": null,
  "text": "DFs shall be determined as follows:\n4.3.1. On at least one test engine representing the configuration chosen to be the most likely to exceed HC + NOx emission limits, and constructed to be representative of production engines, the (full) test procedure emission testing shall be conducted as described in Annex VI after the number of hours representing stabilised emissions.\n4.3.2. If more than one engine is tested, the results shall be calculated as the average of the results for all the engines tested, rounded to the same number of decimal places as in the applicable limit, expressed to one additional significant figure.\n4.3.3. Such emission testing shall be conducted again following ageing of the engine. The ageing procedure should be designed to allow the manufacturer to appropriately predict the in-use emission deterioration expected over the EDP of the engine, taking into account the type of wear and other deterioration mechanisms expected under typical consumer use which could affect emissions performance. If more than one engine is tested, the results shall be calculated as the average of the results for all the engines tested, rounded to the same number of decimal places contained in the applicable limit, expressed to one additional significant figure.\n4.3.4. The emissions at the end of the EDP (average emissions, if applicable) for each regulated pollutant shall be divided by the stabilised emissions (average emissions, if applicable) and rounded to two significant figures. The resulting number shall be the DF, unless it is less than 1,00, in which case the DF shall be 1,00.\n4.3.5. The manufacturer may schedule additional emission test points between the stabilised emission test point and the end of the EDP. If intermediate tests are scheduled, the test points shall be evenly spaced over the EDP (plus or minus two hours) and one such test point shall be at one half of full EDP (plus or minus two hours).\n4.3.6. For each pollutant HC + NOx and CO, a straight line must be fitted to the data points treating the initial test as occurring at hour zero, and using the method of least-squares. The DF is the calculated emission at the end of the durability period divided by the calculated emission at zero hours.\nThe DF for each pollutant for the applicable test cycle shall be recorded in the test report set out in Appendix 1 of Annex VII to Implementing Regulation (EU) 2017/656.\n4.3.7. Calculated deterioration factors may cover families in addition to the one on which they were generated if the manufacturer submits a justification acceptable to the approval authority in advance of EU type-approval that the affected engine families can be reasonably expected to have similar emission deterioration characteristic based on the design and technology used.\nA non-exclusive list of design and technology groupings is given below:\nconventional two-stroke engines without after-treatment system,\nconventional two-stroke engines with a catalyst of the same active material and loading, and the same number of cells per cm2,\nstratified scavenging two-stroke engines,\nstratified scavenging two-stroke engines with a catalyst of the same active material and loading, and the same number of cells per cm2,\nfour-stroke engines with catalyst with same valve technology and identical lubrication system,\nfour-stroke engines without catalyst with the same valve technology and identical lubrication system.",
  "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/III/division/4/division/4.3",
    "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."
}