The use of biofuel is essential for the reduction of greenhouse
gas emission. This paper highlights the use of biodiesel as a means
of reducing greenhouse gas emission from the diesel engine of
heavy-duty vehicles. Biodiesel is fatty acid methyl ester (FAME)
obtained through ester exchange reaction by adding methanol to oil,
such as rapeseed oil, soybean oil, palm oil, etc. The CO₂ emission
from combustion of biodiesel is defined to be equivalent to the CO₂
volume absorbed by its raw materials or plants in their course of
growth. On the other hand, however, biodiesel is known to increase
the NOx emission when compared with operating with conventional
diesel fuel, then suppressing this increase is regarded as a
critical issue.
This study is intended to identify the fuel properties of
biodiesel free from increase in the NOx emission. For this purpose,
multiple kinds of biodiesel differing in fuel properties were used
with the single-cylinder diesel engine, so that the effects of the
difference in fuel properties on combustion and exhaust gas
characteristics were clarified.