For biofuels to succeed in the marketplace, they must be easy to use with a minimum of problems. The Vehicle Technologies Office has collaborated with industry to test biofuel samples and improve both their quality and consistency over time.
Unfortunately, in the mid-2000s, a substantial percentage of biodiesel sold did not meet fuel quality specifications and caused vehicles’ filters to clog. To improve the quality of biodiesel, VTO partnered with the National Biodiesel Board to improve the ASTM International (a standards setting organization) biodiesel fuel specifications. They also took steps to ensure producers adhered to those standards. To guarantee that producers were following the standards, VTO supported work to test representative samples of biodiesel and biodiesel blends.
As a result of VTO’s and the National Biodiesel Board’s work, they found that from 2005 to 2011, there was a large increase in compliance with the ASTM standard. There were fewer impurities in the fuel and biodiesel blends had more consistent concentration levels. In 2012, the National Renewable Energy Laboratory (NREL) conducted a biodiesel market survey which showed that there were very few issues with fuel quality. NREL will release an update to this survey in 2016.
Because of these improvements, many more manufacturers now endorse the use of biodiesel blends in their engines. Currently, all original engine manufacturers accept the use of B5 (5 percent biodiesel) in their vehicles and many accept the use of B20.
VTO has also collaborated with industry to improve ethanol blends. It worked with the Coordinating Research Council, a consortium of original engine manufacturers and oil companies, to sample the quality of E85 (up to 85 percent ethanol) and mid-level ethanol blends (above E10). Before this work was done, E85 often had poor volatility and other quality issues, which can result in poor vehicle operation and driver dissatisfaction. The E85 testing provided critical data and helped ASTM revise the E85 specification to ensure the fuel met quality requirements. The multi-level fuel blend surveys collected data from “blender pumps,” which blend ethanol to various levels such as E15, E20, and E30. This testing provided important data on the consistency of fuel blends from this new type of fueling infrastructure.
VTO is continuing work to improve biofuels quality and better understand its effects on vehicles. It is supporting work to sample and document the quality of B100, as well as investigating the cause of why some biodiesel blends are clogging fuel filters in cold weather conditions. It is also studying how small amounts of metal impurities in the fuel can affect the long-term durability of emission control systems in diesel engines.