Effects of EGR, swirl augmentation techniques on combustion of biodiesel/ethanol and their blends in a diesel engine

Abstract

The diminishing resources and continuously increasing cost of petroleum in association with their alarming pollution levels from diesel engines have caused an interest in finding alternative fuels to diesel which are renewable and sustainable. Emission control and engine efficiency are two most important parameters in current engine design. The impending introduction of emission standards such as Euro IV and Euro V is forcing the research towards developing new technologies for combating engine emissions. The classification of Euro IV and V norms is applicable to heavy-duty engines in Europe, where as Euro 5 is applicable to light-duty engines. This paper presents the effects of exhaust gas recirculation (EGR), swirl augmentation techniques and ethanol addition on the combustion of Honge oil methyl ester (HOME) and its blends with ethanol in a diesel engine. From the experimental work conducted, it is found that the combustion of HOME plus up to 15% ethanol blend in a diesel engine operated with optimised parameters of injection timing 23° Before Top Dead Centre and compression ratio 17.5 results in acceptable combustion emissions and improved brake thermal efficiency (BTE). The addition of ethanol increased BTE with reduced hydrocarbons (HCs), CO and smoke emissions. However, NOx emissions increased dramatically. Use of appropriate EGR reduces NOx to acceptable levels. The implementation of swirl augmentation techniques further resulted in increased BTE and considerable reduction in tail pipe emissions such as smoke, HCs, CO and NOx. The effect of swirl by providing grooves on the piston was taken into consideration to find the overall biodiesel engine performance, which gives scope for further studies. © 2013 Copyright Taylor and Francis Group, LLC.