71. The Chair of the informal group on GFVs proposed an amendment to UN Regulation No. 115 (GRPE-63-06-Rev.1), redefining the class of bi-fuel vehicles regarding the simultaneous use of gas and petrol in gas mode under certain conditions. This is similar to the amendment in UN Regulation No. 83 (paragraph 53, agenda item 8(a)).
72. GRPE agreed to distribute an updated version of GRPE-63-06-Rev.1 as an official document for consideration at its June 2012 session.
Mr Rijnders indicated that the documents GRPE 63-5 (R.83) and 63-06 (R.115) are informal documents for this GRPE.
Mr. Piccolo indicated that the group decided to look at a re-definition of bi-fuel vehicles to include new technologies making a more intensive use of gasoline in gaseous fuel vehicles, instead of providing ad-hoc provisions for gas systems intended to be fitted on direct injection petrol engines, in retrofit or new applications.
A common requirement for all types of systems has been defined: the use of petrol simultaneously with gas during the Type I test cycle is permitted provided that the energy consumption of the gaseous fuel is higher than 80% of the total amount of energy consumed during the test.
A gas energy ratio has been preferred to a petrol one since gas consumption measurement has been considered easier and more accurate.
Mr. Rijnders indicated that the proposals were agreed in the last GFV meeting but ask again if there are additional comments. Mr. Tappe (CLEPA/Bosch) notes that the present paragraph 3.2.5. of Annex 12 permits, within the maximum time frame of 60secs, the use of petrol during the entire test, while the proposed amendments would allow the use of pure petrol exclusively in the start-up phase;
Mr. Tappe pointed out that there are systems using the 60 seconds of petrol split over the cycle and not necessarily only in the starting phase.
He proposes to re-extend this possibility also to the rest of the driving cycle, adding the wording “only or” in the paragraph 3.2.5 of Annex 12 just after the first part of the sentence: “Without prejudice to paragraph 6.4.1.3. of Annex 4a, during the Type I test it is permissible to use petrol….”.
TUV remarks that recalculation of dilution factors might be needed because they do not take into consideration the use of different fuels.
Mr. Rijnders indicated that presently recalculation the use of petrol up to 60 seconds is not considered because the effect is negligible. Only for simultaneous use of the fuels is a recalculation is introduced. The dilution factors as well as fuel density of gas only are used in the calculations of the final emissions in gram/km, since these represent the “worst case” conditions. This basic assumption generates emission values (g/km) higher than those that would be generated by weighted factors and a mean density.
Mr. Piccolo brings forth document GFV-16-02, where there are detailed explanations on why the present calculation procedures of emissions, based only on gas parameters are not affected by the proposed amendments and do not need to be adapted.
Oliver Eberhardt (BMU, Germany) asked why extend the possibility to increase the use of petrol.
Mr. Rijnders explained the technical reason: in the gas mode, petrol injectors placed directly in the combustion chamber (direct injection) could be over-heated if not cooled by the passage of some petrol.
Mr. Erario asked if there will be an amendment from CLEPA because he is concerned there already is a document on the table for GRPE.
Mr. Rijnders indicates that if this point should be agreed here, it can be included in the informal document as proposed by GFV. Otherwise it would have to be included as an amendment from CLEPA.
It is decided that CLEPA and AEGPL will work together to create amended language that will be included in the GRPE document as a GFV ‘amendment’.