42. AEGPL points out the modifications made to the doc GFV-15-02 with respect of doc GFV-14-02, in line with the two comments received in the previous meeting of the group:

• a. Insertion of 80% energy minimum limit for LPG use in the definition of “bi-fuel type B vehicle” (see point 49 of the minutes GFV-14-06)
• b. Simultaneous extension of both proposals (R 115 and R83) to CNG (see point 53 of the minutes GFV-14-06)

43. NGVAE raises the issue of how to measure the actual gas consumption of such a system. In this definition, if the vehicle runs on less than 80% then the vehicle could not be homologated. In discussion, it is determined that the regulatory language can include flexibility in the methods of measuring the fuel consumption under this vehicle definition.

44. NGVAE raises a concern about the definition of a Bi-Fuel Type B being confused with a dual-fuel. NGV Global indicates that they share this same concern.

45. AEGPL highlights that dual-fuel definitions, as finally proposed, regard only diesel-gas vehicles, while the definitions under discussion relate only to petrol-gas cases, thus remaining in the topic of positive-ignition engines (same driving cycle, same emission limits,etc.);

46. TNO makes several comments and proposals:

• a. Definitions: rephrase the bi-fuel general definition in order to re-include bi-fuel Type A and B in the same “category” of vehicles;
• b. Minimum limit of gas use: convert it into a maximum limit of petrol use, and motivate the value of 80% that seems too low:
• c. Energy ratio calculation:
  • i. gas mass measurement: provide a suitable alternative method to static weighing of gas container – such as mass flow metering – ensuring the same accuracy;
  • ii. gas ratio calculation: provide more details on formula because it appears as a mass ratio rather than an energy ratio

47. In response to TNO comments, AEGPL observes:

• a. Definitions: a common definition of bi-fuel vehicle is agreeable and even better;
• b. Minimum limit of gas use: the choice of a gas limit instead of a petrol limit was due to the fact that petrol consumption is very low and, furthermore, it would be difficult to be measured with simple instruments, in a bench test; data will be collected to promote the value of 80%;
• c. Energy ratio calculation:
  • i. Gas mass measurement: allowing a possible alternative method with the same accuracy is agreeable; with particular reference to mass flow metering, AEGPL points out that the reliability of such type of instrument – on gas – seems not proven yet in transient conditions and, furthermore, its positioning and installation, in a bench test, might raise some problems, likely affecting reproducibility of the measurement method;
  • ii. Gas ratio calculation: it is an energy ratio where the heating value of gas has been deleted at the numerator and denominator; in fact, FC is conservatively determined considering the cycle is driven exclusively on gas;

48. There is an extended discussion about the definitions now specifying a Type A and Type B bi-fuel; the test procedures;; the possible combination of the current provision allowing only 60 seconds running on petrol and the new one setting an energy percentage limit;

49. Consensus: AEGPL will come with a new proposal taking into account the following:

• a. Definition of bi-fuel vehicles will be revised in accordance with TNO proposal;
• b. Minimum limit for gas use: data supporting 80% value will be collected and provided to the group;
• c. Energy ratio calculation:
  • i. Gas mass measurement: a safeguard clause allowing different but equivalent methods will be added;
  • ii. Gas ratio calculation: a detailed demonstration of the formula will be circulated to the group; an analytical explanation of the conservative approach of the formula when using FC calculated on gas only will be sent to the group;
• d. Petrol use in gas mode: a proposal aimed at combining the current time-based limit and the new energy-based cap will be submitted to the group;

50. There is a request (in abstentia) from Mr. Radzimirski about provisions in the scope of the regulation that must be considered, but this will be brought up again in a future meeting.