The engine fuel filter blocking problem in vehicles running on biodiesel blends surfaced in 2007. Researchers discovered that this problem was due to the presence of steryl glucosides at very low level, less than 100 mg kg-1. In October 2008, the American Society for Testing and Materials (ASTM) incorporated a new parameter called the cold soak filtration test (CSFT) in the revised specification for biodiesel blend stock (B100) for middle distillate fuels (ASTM D6751-08). A CSFT time of 360 s and 200 s was set as the upper limit for both normal and low temperature conditions (at or below-12C), respectively.

Main Research: Yung Chee Liang