This proposal describes a modification to previous formulas in order to take into account the presence of inert gas and providing the correct energy ratio.

Documents GRPE/2012/7 (referring to R115) and GRPE/2012/6 (referring to R83) introduce the calculation of NG/biomethane energy ratio during a Type I Cycle by weighting the NG/biomethane mass consumed. The formulas introduced respectively in Annex 6B (GRPE/2012/7) and Annex 12 – Appendix 2 (GRPE/2012/6) are affected by an error when G25 reference fuel is used. The error is due to the presence of inert gas (N2) in the G25 reference fuel, varying from 12 to 16% in molar fraction units.

The proposal in document GFV 20-05 indicates a preferred formula. Mr. Dekker suggests that the process being proposed does not need to include a complex formula since a standard reference fuel is being used. Possibly the calculation and proposal itself can be used as a rationale to support the reference fuel.

It is agreed to take on the proposal but Mr. Rijnders asks if we can agree to accept a fixed factor as opposed to a calculation. Mr. Piccolo and Mr. Castagnini agree. A fixed correction factor of .78 is acceptable.

Procedural aspect: Can this be made as a corrigendum or is another informal document required? This is a correction of something that has been overlooked. The informal document also can become a formal document and they can be merged together. But an informal document must be prepared, and it is now late to launch this to the GRPE.

The resolution is that we accept the document and proposal but that some corrections are needed. If corrections can be made immediately we can submit it as an informal document this week and the GFV secretariat will send it to the GRPE secretariat for submittal as an informal document. The difference between the proposals is that R.115 is restricted to direct injection engines but that R.83 is more general and not applicable only to direct injection engines.