Experimental assessment of performance and exhaust emission characteristics of a diesel engine fuelled with Punnai biodiesel/butanol fuel blends

This work examines the effect of butanol as an oxygenated additive to lower carbon monoxide, smoke, nitrogen oxide and hydrocarbon emissions and to improve the performance aspects of Calophyllum inophyllum (Punnai) biodiesel. Single-cylinder, oil-cooled compression ignition engines are employed in this work. Neat Punnai biodiesel (P100) is blended with butanol at 10% and 20% by volume and labelled as B10P90 and B20P80, respectively. Methanol and alkaline catalyst (KOH) were used for the transesterification process for biodiesel production. The transesterification technique yielded 88% biodiesel from raw Punnai oil. Engine tests resulted in lower CO, smoke, NOx and HC emissions when fuelled with both butanol blends when compared to P100. In addition, BSFC (brake-specific fuel consumption) reduced and BTE (brake thermal efficiency) increased with the inclusion of butanol blends (B10 and B20) to neat Punnai biodiesel.