Performance and emission studies of a LPG fueled spark ignition engine with steam induction

Abstract

In this study the combustion and emission characteristics of a conventional naturally aspirated, four-cylinder, multipoint port fuel injection S.I engine modified to run with liquefied petroleum gas (LPG) injection along with steam induction are evaluated. Experiments are conducted at wide-open throttle condition and at a speed range of 2000 rpm to 4500 rpm with a static ignition timing of 6-degree bTDC. The steam flow rates of 10 to 25% of LPG flow rates (by mass) are used. The results with LPG and 25% steam induction at wide-open throttle condition and 3500 rpm indicates that the brake thermal efficiency has reduced by 2%, and the peak cylinder pressure has reduced by about 10 bar, with the location of the peak pressure being way from top dead centre when compared to LPG combustion. Oxides of nitrogen emission has reduced significantly with the induction of steam with a reduction of 45% when compared to LPG at 3500 rpm. The carbon monoxide and unburnt hydrocarbon emissions at the above condition have increased marginally. Thus the induction of steam along with LPG has resulted in notable reduction in the oxides of nitrogen emissions with a slight reduction in engine performance.