Investigation on the Performance and Emission Characteristics of Biodiesel and its Blends with Oxygenated Additives in a Diesel Engine

An experimental investigation is carried out to evaluate the effects of biodiesel-dimethylcarbonate (BC) blends and biodiesel-diglyme (BG) blends on the combustion, performance and emission characteristics of a diesel engine at different loads and constant engine speed. The results show that for a specific engine load, compared with biodiesel, the ignition delay increases with the increase of dimethyl carbonate fraction in the blends while it decreases with the increase of diglyme (dimethylene glycol dimethyl ether) fraction in the blends. Compared with biodiesel, for a specific engine load, the total combustion duration decreases with the increase of both dimethyl carbonate and diglyme fraction in the blends. Compared with biodiesel, for a specific engine load, the BC blends have lower peak cylinder pressure at full load, while the BG blends show a slight variation in the peak cylinder pressure. The heat release rate is higher during premixed combustion phase for BC blends and lower for BG blends than for biodiesel at full load. In comparison with biodiesel, the BC and BG blends have slightly higher brake thermal efficiency. Drastic reduction in smoke is observed with BC and BG blends at higher engine loads. The BSNO_x emissions are found slightly lower for BE and BC blends at all loads. The BC blends have a slight variation in the BSHC and BSCO emissions while the BG blends have lower BSHC and BSCO emissions at all loads.