Assessment of Effect of Load and Injection Timing on the Performance of Diesel Engine Running on Diesel-Biodiesel Blends

Abstract

Biodiesels have many advantages over petroleum diesel in terms of their usage as alternative to diesel. The reduction in harmful engine emissions like CO, smoke, HC emissions have been associated with the biodiesel use. The present work was undertaken to analyze the performance and emission characteristics of the biodiesel produced from Jatropha curacs (JB100) and Pongammia (Karanja)(KB100) and their respective blends(JB20, JB50, KB20 and KB50) and to compare with those of the diesel. Constant speed, air cooled, single cylinder DI diesel engine that commonly is used in agricultural sector. The effect of blending biodiesel with diesel, load variations and variation of injection timings were studied on the Brake thermal efficiency (BTE), Brake specific fuel consumption (BSFC), smoke emissions, NOx emissions, HC emissions and exhaust gas temperatures (EGT) of the fuels tested. Increase in BSFC was observed with increasing the proportion of biodiesel in the diesel-biodiesel blend. BTE of diesel was highest at low loads where as JB20 had highest efficiency at high loads and all injection timings. Addition of biodiesels to diesel also improved the smoke emissions and HC emissions however the NOx emissions increased with addition of biodiesel. EGT of diesel were lower than those with the 20% and 50% blends but higher than those of pure biodiesels. Advancing the injection timing increased BTE and decreased BSFC, Smoke and HC emissions. NOx emissions, however, increased due to advanced injection timing.