{
  "url": "https://openlegislation.uk/eu-regulation-2017-654/annex-VI/division-9/division-9.2/division-9.2.3/division-9.2.3.2",
  "json_url": "https://openlegislation.uk/eu-regulation-2017-654/annex-VI/division-9/division-9.2/division-9.2.3/division-9.2.3.2.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/VI/division/9/division/9.2/division/9.2.3/division/9.2.3.2",
  "kind": "division",
  "number": "9.2.3.2",
  "heading": "Dilution",
  "text": "The temperature of the diluents (ambient air, synthetic air, or nitrogen as quoted in point 9.2.1) shall be maintained between 293 and 325 K (20 to 52 °C) in close proximity to the entrance into the dilution tunnel.\nDe-humidifying the dilution air before entering the dilution system is permitted. The partial flow dilution system has to be designed to extract a proportional raw exhaust gas sample from the engine exhaust gas stream, thus responding to excursions in the exhaust gas stream flow rate, and introduce dilution air to this sample to achieve a temperature at the test filter as prescribed by point 9.3.3.4.3. For this it is essential that the dilution ratio be determined such that the accuracy requirements of point 8.1.8.6.1 are fulfilled.\nTo ensure that a flow is measured that corresponds to a measured concentration, either aqueous condensation shall be prevented between the sample probe location and the flow meter inlet in the dilution tunnel or aqueous condensation shall be allowed to occur and humidity at the flow meter inlet measured. The PFD system may be heated or insulated to prevent aqueous condensation. Aqueous condensation shall be prevented throughout the dilution tunnel.\nThe minimum dilution ratio shall be within the range of 5:1 to 7:1 based on the maximum engine exhaust gas flow rate during the test cycle or test interval.\nThe residence time in the system shall be between 0,5 and 5 s, as measured from the point of diluent introduction to the filter holder(s).\nTo determine the mass of the particulates, a particulate sampling system, a particulate sampling filter, a gravimetric balance, and a temperature and humidity controlled weighing chamber, are required.",
  "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/VI/division/9/division/9.2/division/9.2.3/division/9.2.3.2",
    "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."
}