Division 1.2.2 Exhaust emissions type-approval of an engine running on natural gas/biomethane or LPG and designed for operation on one specific fuel composition.F1

The parent engine shall meet the emission requirements on the reference fuels G _R and G ₂₅ in the case of CNG, on the reference fuels G _R and G ₂₀ in the case of LNG, or on the reference fuels A and B in the case of LPG, as specified in Annex IX. Fine-tuning of the fuelling system is allowed between the tests. This fine-tuning will consist of a recalibration of the fuelling database, without any alteration to either the basic control strategy or the basic structure of the database. If necessary, the exchange of parts that are directly related to the amount of fuel flow such as injector nozzles is allowed.