The Charter was first established in 1998 to increase understanding of the fuel quality needs of motor vehicle and engine technologies and to promote fuel quality harmonization worldwide in accordance with those needs. The Charter matches fuel specifications to the vehicle and engine specifications required to meet various customer needs around the world.

As many countries take steps to require vehicles and engines to meet strict fuel economy standards in addition to stringent emission standards, Category 5, which raises the minimum research octane number (RON) to 95, will enable some gasoline technologies that can help increase vehicle and engine efficiency.

Increasing the minimum octane rating available in the marketplace has the potential to help vehicles significantly improve fuel economy and, consequently, reduce vehicle CO₂ emissions. While the improvement will vary by powertrain design, load factor and calibration strategy, among other factors, vehicles currently designed for 91 RON gasoline could improve their efficiency by up to three percent if manufacturers could design them for 95 RON instead. Octane rating is becoming an especially important limiting factor in future efficiency improvements because new, more efficient engine designs, such as smaller displacement turbo-charged engines, are approaching their theoretical knock limits when using lower octane rated gasoline. Raising the minimum market octane to 95 RON will enable manufacturers to optimize powertrain hardware and calibrations for thermal efficiency and CO2 emissions. All of these technologies and actions will be needed to meet the highly challenging fuel economy and CO2 requirements emerging in many countries.

—Worldwide Fuel Charter 5^th ed.

For diesel fuel, this category establishes a high quality hydrocarbon-only specification that takes advantage of the characteristics of certain advanced biofuels, including hydro-treated vegetable oil (HVO) and Biomass-to-Liquid (BTL), provided all other specifications are respected and the resulting blend meets defined legislated limits.

Other changes from the previous edition include a new test method for trace metals and an updated gasoline volatility table.

Significant changes relate to biodiesel: the Charter now allows up to 5% biodiesel by volume in Category 4 diesel fuel; has new diesel fuel oxidation stability limits; and includes an alternative oxidation stability test method with correlations to other methods. The Charter also now references the E100 and B100 Guidelines published by the World Wide Fuel Charter Committee in 2009.

As countries move toward more stringent vehicle and engine requirements, fuel quality’s role in preserving the functionality of vehicles and engines continues to grow. Sulfur-free and metal-free fuels remain critical prerequisites for ultra-clean, efficient and durable emission control systems. The most advanced vehicles and engines require the best fuel quality to meet their design potential.

Resources

• Worldwide Fuel Charter 5^th ed. (2013)