Impact Study of High Biodiesel Blends on Performance of Exhaust Aftertreatment Systems

Biodiesel Fuel (BDF) Research Work Group works on identifying technological issues on the use of high biodiesel blends (over 5 mass%) in conventional diesel vehicles under the Japan Auto-Oil Program started in 2007. The Work Group conducts an analytical study on the issues to develop measures to be taken by fuel products and vehicle manufacturers, and to produce new technological findings that could contribute to the study of its introduction in Japan, including establishment of a national fuel quality standard covering high biodiesel blends. For evaluation of the impacts of high biodiesel blends on performance of diesel particulate filter system, a wide variety of biodiesel blendstocks were prepared, ranging from some kinds of fatty acid methyl esters (FAME) to another type of BDF such as hydrotreated biodiesel (HBD). Evaluation was mainly conducted on blend levels of 20% and 50%, but also conducted on 10% blends and neat FAME in some tests. The evaluation test items include balance point temperature (BPT), DPF regeneration rate, active regeneration control of DPF system, PM composition analysis, and so on. The study results showed that high biodiesel blends had a small impact on BPT and DPF regeneration rate. On the other hand, concern was raised about high biodiesel blends in active regeneration control of DPF.