WWFC Committee releases Worldwide Fuel Charter for Methane-Based Transportation Fuels
28 October 2019
The Worldwide Fuel Charter (WWFC) Committee—representing engine and vehicle manufacturers grouped in ACEA, Auto Alliance, EMA and JAMA—released the first edition of the Worldwide Fuel Charter for Methane-Based Transportation Fuels. The document presents recommendations for methane-based fuel quality specifications for markets with the most advanced motor vehicles and engines, as well as for markets with less advanced vehicles and engines.
As the use of methane-based fuels for transportation has grown rapidly in recent years, and the quality of these fuels varies widely around the world, the Committee saw a need to provide information about these fuels and how to match their quality with the needs and capabilities of modern vehicle and engine technologies. The Methane-Based Fuels Charter recommends quality specifications for methane-based fuels used for transportation purposes, including compressed natural gas (CNG), liquefied natural gas (LNG) and biogas.
Like the Worldwide Fuel Charter for Gasoline and Diesel Fuel, the Methane-Based Fuels Charter divides the vehicle and engine markets into categories of increasing performance and emissions regulations. Moving from the lowest category (least stringent performance and emission controls) to the highest (the most stringent requirements) will typically achieve improved performance and lower emissions from the vehicles and engines using the fuel specified for the category.
The Methane-Based Fuels Charter provides recommendations for Categories 3, 4, and 5 to closely match the emission controls for each category with their gasoline and diesel fuel equivalents in the Worldwide Fuel Charter. In the Gasoline and Diesel Fuel Charter, Category 1 and 2 fuels were intended for markets with no emission controls or first generation emission controls such as US Tier 1, Euro 2/II, or Euro 3/III. Methane-based fuels are inherently cleaner, however, so engines/vehicles that are able to use methane generally meet the more stringent emission control requirements aligned with the Gasoline and Diesel Fuel Charter’s Category 3 and above; therefore, Categories 1 and 2 are not listed in the Methane-Based Fuels Charter.
The methane-based fuel categories defined in the Charter are:
- Category 3—Basic quality for methane-based fuels, recommended for use in natural gas vehicles/engines with either no emission controls or stoichiometric positive-ignition engines and 3-way emission control catalysts.
- Category 4—Higher methane-based fuel quality, recommended for use in natural gas vehicles/engines with advanced exhaust aftertreatment and/or enhanced performance (e.g., positive-ignition engines with a high compression ratio), or having other market demands.
- Category 5—Highest methane-based fuel quality, recommended for use in natural gas vehicles/engines with highly advanced exhaust aftertreatment and/or enhanced performance, or having other market demands. Category 5 markets require the highest Methane Number (MN ≥ 75) and energy content (Wobbe Index, WI ≥ 46 MJ/m3) fuel that simultaneously enables a longer driving range and higher fuel efficiency.
The WWFC Committee also published the sixth edition of the Worldwide Fuel Charter for Gasoline and Diesel Fuel. The sixth edition of the WWFC updates the fifth edition in several ways and presents each fuel in its own chapter for easier reading. The gasoline chapter introduces a new Category 6 to address anticipated vehicle and engine regulations for emission control and fuel efficiency in certain major markets.
Also, it introduces new metrics to help reduce particle emissions. Notably, in light of global progress on gasoline quality since the WWFC was first published more than two decades ago, the sixth edition has retired Category 1 gasoline as obsolete. Category 1 diesel fuel has been retained, but only as guidance to a transitional quality fuel—the Committee intends to retire Category 1 diesel fuel in a future edition.
Source: ACEA