Combustion Analysis of Polanga (<i>Calophyllum inophyllum</i>) Biodiesel

Abstract

There is a mounting concern in many countries to explore fuels that are environment friendly. Although straight vegetable oils can be used in diesel engines, there are limitations in their usage due to their high viscosity, low volatility, and poor cold flow property. Biodiesel is a fatty acid alkyl ester, which can be derived from any vegetable oil by transesterification. Biodiesel is a renewable, biodegradable and non-toxic fuel. In the present study, polanga (Calophyllum inophyllum) oil was transesterified with methanol using sodium hydroxide as catalyst to obtain polanga biodiesel. To evaluate the combustion analysis, polanga biodiesel was tested in a single-cylinder, four-stroke, direct-injection, constant speed, diesel engine. The results were compared with combustion characteristics of diesel fuel. The result showed that polanga biodiesel exhibits similar combustion characteristics as that of diesel. The actual start of injection and start of combustion were found to be earlier for polanga biodiesel as compared to diesel. The ignition delay period was found to be shorter with polanga biodiesel. The magnitude of peak heat release rate and peak pressure was observed to be lower for polanga biodiesel. Though the location of peak heat release rate was earlier for polanga biodiesel, its peak pressure location was found be delayed when compared to diesel. Polanga biodiesel exhibits a shorter combustion duration than diesel. Since the measured parameters for biodiesel differs only by a smaller magnitude when compared with diesel, this investigation ensures the suitability of polanga biodiesel as a fuel for CI engines.