# Commission Regulation (EU) No 582/2011 of 25 May 2011 implementing and amending Regulation (EC) No 595/2009 of the European Parliament and of the Council with respect to emissions from heavy duty vehicles (Euro VI) and amending Annexes I and III to Directive 2007/46/EC of the European Parliament and of the Council (Text with EEA relevance), Division 7.2.3.4: For CNG engines, including dual-fuel engines, all those tests may be conducted with market fuel in the following way:

Extent: E+W+S+N.I.

(a)for H marked engines with a market fuel within the H-range (0,89 ≤ S λ ≤ 1,00);
(b)for L marked engines with a market fuel within the L-range (1,00 ≤ S λ ≤ 1,19);
(c)for HL marked engines with a market fuel within the extreme range of the λ-shift factor (0,89 ≤ S λ ≤ 1,19).
However, at the manufacturer’s request, the reference fuels specified in Annex IX may be used. This implies tests as described in Section 1 of this Annex.

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Source: https://www.legislation.gov.uk/eur/2011/582/annex/I/division/7/division/7.2/division/7.2.3.4 (the official version)
Page: https://openlegislation.uk/eu-regulation-2011-582/annex-I/division-7/division-7.2/division-7.2.3.4
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.