The application of biodiesel as an alternative fuel for
petroleum diesel fuel is very effective for the reduction of CO₂
emission, because biodiesel is produced from renewable biomass
resources. In Japan, neat biodiesel derived from waste cooking oil
has often been applied to commercial vehicles. However, it is
possible that the difference of fuel properties between
conventional diesel fuel and biodiesel causes the problems on
exhaust emission characteristics of diesel engine. Therefore, it is
necessary to clarify the effect of biodiesel fuelling on exhaust
emissions from commercial vehicles.
Light-duty garbage trucks and heavy-duty diesel buses which were
actually fueled with biodiesel in Kyoto, Japan, were used for test
vehicles in this study. The exhaust emissions from these vehicles
during JE05 mode tests were compared between biodiesel derived from
waste cooking oil and conventional diesel fuel.
As a result, the application of biodiesel to older vehicles did
not cause a negative effect on the exhaust emissions. On the other
hand, biodiesel blending deteriorated NOx emission from new
vehicles. In addition, other problems related to the use of
biodiesel have been reported (e.g., oil dilution in vehicles
equipped with DPF, etc.). Therefore, it will be necessary to modify
engine components for the improvements of safe and environmental
performances when using biodiesel.