The emission, performance and combustion characteristics of croton biodiesel blends were tested in a direct injection (DI) single
cylinder four stroke diesel engine. The physico-chemical properties of the biodiesel blends were all found to be within the standard
ASTM values. The reduction in exhaust smoke emissions for the biodiesel blends ranged from 10% to 41% at maximum engine load
of 10 Kg while a slight increase in NOx emissions was observed with increase in concentration of biodiesel in the blends. Similar
general increase in brake thermal efficiency (BTE), temperature of exhaust emissions and fuel flow rate was observed with increasing
engine load for both petro-diesel and biodiesel blends. The difference between BTE for petro-diesel and biodiesel blends ranged from
2.04 to 5.03%. The brake specific energy consumption (BSEC) decreased with increasing engine load for both petro-diesel and
biodiesel blends. An increase in both engine pressure and heat released was observed with increase in concentration of biodiesel in the
blends. The difference in maximum engine pressure ranged from 1.05 bar at 0 Kg to 3.77 bar at 10 Kg load. The greatest difference in
maximum engine pressure was recorded between petro-diesel and B50 blend. The observed difference in position of peaks for
maximum heat released showed that there was slight delay in ignition of biodiesel blends as compared to petro-diesel. The results
obtained in this study showed that higher blends of up to 50% biodiesel can be effectively used as an alternative to petro-diesel without
compromising the engine performance.
Key words:Croton biodiesel blends, Diesel engine, Emission and performance characteristics.