Abstract:

Tests were carried out in an electric controlled high pressure common rail diesel engine to research on
microscopic characteristics of particle emitted from a diesel engine fueled with biodiesel. A diesel engine fueled with
different proportions of biodiesel/diesel blends was operated stably at 2 000 r/min and 225 N·m. The fractal dimension
of the particles emission was calculated according to the Brasil algorithm using high-resolution transmission electron
microscope (HRTEM). The results show that spherical primary particles of which mean diameter ranged between 26.56
nm and 28.61 nm consist of the particles exhibiting characteristics of fractal structure generated by the combustion of the
fuels with biodiesel volume fraction of 0%, 10% and 50%. Mean diameter of primary particles for fuel with volume fraction
of biodiesel of 100% is 45.57 nm, which is quite different from the other three kinds of fuels. With increasing percentage of
Pistaciachinensis Bunge seed biodiesel, fractal dimension increases gradually and primary particles become more close
while mean fringe separation distances decrease and the oxidation activities become lower.

Key words: high pressure common rail diesel engine, biodiesel, high-resolution transmission electron microscope (HRTEM), fractal dimension, fringe separation distance