For the B10 fuel the brake thermal efficiency is
improved compared to pure diesel and for B15 fuel, it is
almost same of pure diesel. The possible reason for this
improvement is the molecules of biodiesel contain some
amount of excess oxygen which takes part in the
combustion process. It is noticed from the figures that,
with EGR the brake thermal efficiency increases a bit,
due to increase of the combustion velocity, caused by
higher intake charge temperature. Disassociation of
carbon dioxide to form free radicals can also be credited
to this improvement in efficiency.