Particulate emission and physical properties of particulate matter emitted from a diesel engine fueled with ternary fuel (diesel-biodiesel-ethanol) in blended and fumigation modes

The present study aimed to explore the influences of different fueling modes, including diesel alone, blended, fumigation and a combined fumigation + blended (F + B) modes, on the particulate emission and physical properties of particulate matter (PM) emitted from a 4-cylinder diesel engine fueled with a ternary fuel (diesel-biodiesel-ethanol, DBE) under two engine speeds and loads. Biodiesel-ethanol (BE) fuel was mixed with diesel fuel in the blended mode; but it was sprayed into the intake air manifold in fumigation mode. In the F + B mode, half of the BE fuel was sprayed into the intake air manifold (same as fumigation mode); while another half of it was mixed with diesel to produce the DBE fuel (same as blended mode). The blended, fumigation and F + B modes had the same fuel composition (D80B5E15, volume %) for comparison of their impacts. According to the average results, the blended mode has lower PM mass, total number concentration (TNC) and geometric mean diameter (GMD) compared to the fumigation mode. In respect of the PM physical properties, the blended mode has lower primary particle size, fringe length, tortuosity and fringe separation distance compared to the fumigation mode. The magnitudes of all the parameters investigated in the F + B mode are in between those of the fumigation mode and the blended mode. Despite of using the same fuel of D80B5E15, the blended and fumigation modes show different effects on the PM emission; this finding shows that the effect of fueling type is stronger than fuel type. It can be summarized that the application of DBE in the blended mode has effect on reducing the PM emissions, especially PM mass (-42.5%), TNC (-22.3%) and GMD (-8.8%), while fumigation mode has almost no effect on the PM mass and GMD but causes increase in TNC (36.2%) compared to diesel mode.