NGV Provisions Discussed at UNECE GRPE Meeting in Geneva

| Switzerland, Geneva

UNECE GRPE BannerThe UNECE Working Party on Pollution and Energy (GRPE) is the subsidiary body of the World Forum for Harmonization of Vehicle Regulations (WP.29) that prepares regulatory proposals on pollution and energy efficiency to WP.29.  This group of experts, which includes representation from NGV Global, conducts research and analysis to develop emission and energy requirements for vehicles. NGV Global reports here, on the two provisions related to natural gas vehicles (NGV) that were on last week’s agenda in Geneva.

Amendment to R.49, Emissions of compression ignition and positive ignition (LPG and CNG) engines

The International Organization of Car Manufacturers (OICA) introduced provisions to harmonize UNECE Regulation 49 with those in Europe (Emissions of compression ignition and positive ignition (LPG and CNG) engines).  There are only a few implications for NGVs and natural gas within this new harmonization of the UNECE regulation with EU regulations:

  1. related to gas composition;
  2. measurement options for either THC (total hydrocarbons or NMHC (non-methane hydrocarbons), and
  3. the addition of biomethane as part of the parameters for ‘natural gas.’

Supplement to the draft Regulation on uniform provisions concerning the approval of Heavy Duty Dual-Fuel Engine Retrofit Systems (HDDF-ERS) to be installed on heavy duty diesel engines and vehicles

An amendment to replace back-to-back testing requirements of dual-fuel engines was proposed by the European LPG Association (AEGPL) because in some cases the hydrocarbons (HC) and/or carbon monoxide (CO) emission values of the original diesel engine are far below the emission limit, which could make it impossible for gas to pass the emissions test.  A solution was developed by using a CO2 specific emissions approach.

CO2 specific emission results in the dual-fuel mode shall not exceed the applicable original emission limits for diesel operation as specified in Regulation No. 49 and transposed into CO2 specific emission limits using a new formula created for this purpose.


The next meeting of the GRPE will be held on 11-12th January 2018.

GRPE convenes officially twice a year and entrusts informal groups with specific problems that need to be solved urgently or that require special expertise.  More than 120 experts participate at the sessions of GRPE.

NGV GlobalNGV Global welcomes inquiries about the association’s involvement in UNECE and ISO activities, by email to

(Sources: NGV Global, UNECE)

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