PERFORMANCE OF DIESEL ENGINE FUELLED WITH BIODIESEL-BUTANOL BLENDS

Diesel engine designed to operate on the regular diesel oil shows unsatisfactory performance with biodiesel. The reason is the difference in fuel's properties. The negative effect of biodiesel properties could be mitigated by use of fuel additives. Goal of this research was the improvement of the performance of diesel engine running on biodiesel by addition of butanol. Jatropha biodiesel and its blends with butanol have been tested in the four stroke direct injection air cooled diesel engine. The engine fuelled with the blend made up of 80% of biodiesel and 20% of butanol has shown improved by 2% fuel conversion efficiency and decreased by 3% nitrogen oxides, by 17% smoke, and by 15% carbon monoxide emissions in comparison with pure biodiesel. Analysis of fuel injection and combustion characteristics revealed that such a change in engine outputs was the net result of an earlier by 0.5 degree start of fuel injection, longer by 1.2 degree ignition delay period and later by 0.8 degree start of combustion of blend as compared to pure biodiesel. It was also shown that effect of butanol is proportional to its fraction in the blend. It was also concluded that satisfactory engine operation with biodiesel can be achieved by alcohol additive without engine modification.