The use of CNG in heavy-duty engines using a small amount of diesel as a pilot is increasing. Some companies have been developing this technology for more than 20 years.
At the Roundtable for Harmonization of Regulations Codes and Standards held in Geneva in January 2007, one of the recommendations was that there is a need for standards for dual fuel vehicles. This recommendation was acted on by ISO (International Standardization Organization) whose Technical Management Board referred the matter to one of its subcommittees, TC22/SC25, which is concerned with vehicle equipment. After consideration, that subcommittee decided that it would take no further action unless somebody submitted a request for a dual fuel related standard to be written.
Since this decision seemed to be at variance with the recommendation from the Roundtable, I organized a conference with two of the manufacturers of dual fuel systems. From this conference it was concluded that TC22/SC25 was indeed correct and that no new equipment related standards are needed. The existing equipment and safety standards (including those currently being written for LNG) relating to CNG, LNG and diesel (e.g. CNG cylinder and filling nozzle standards) are quite appropriate for the dual fuel situation.
Readers of NGV Global, especially dual fuel manufacturers, are invited to comment on this conclusion, especially if they feel there is a need for additional equipment related and safety standards. Please send an e-mail to iangv@iangv.org.
This request for comment does not apply to vehicle type approval and certification. It is recognized that there are a number of difficulties for dual fuel manufacturers in this area.
Garth Harris
Secretary-General
IANGV
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