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:F1

1. (a)

   for H marked engines with a market fuel within the H-range (0,89 ≤ S _λ ≤ 1,00);

2. (b)

   for L marked engines with a market fuel within the L-range (1,00 ≤ S _λ ≤ 1,19);

3. (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.