Performance and Combustion Characteristics of a DI Diesel Engine Fueled with Jatropha Methyl Esters and its Blends

This study discusses the performance and combustion characteristics of a direct injection diesel engine fueled with Jatropha methyl ester (JME). In order to determine the performance and combustion characteristics, the experiments were conducted at the constant speed mode (1500rpm) under the full load condition of the engine on a single cylinder 4-stroke CI engine. The results indicate that when the test engine is fuelled with JME, the engine performance slightly weakens, the combustion characteristics slightly change when compared to a petroleum based diesel fuel. The biodiesel causes reduction in carbon monoxide (CO), unburned hydrocarbon (HC) emissions, but they cause increases in nitrogen oxides (NOx) emissions. The useful brake power obtained is similar to diesel fuel for all loads. The oxygen content in the exhaust is more with JME blend due to the fact that fuel itself contains oxygen .The trend of oxygen emission is similar to diesel fuel for all loads. Since JME contains 11% oxygen by weight and this oxygen helps to oxidize the combustion products in the cylinder, especially in rich zones, the addition of JME decreases CO emission. Although there has not been a significant difference in NOX emissions at part load. NOx is slightly increased due to the higher combustion temperature and the presence of fuel oxygen with the blend at full load. JME as a new Biodiesel and its blends can be used in diesel engines without any engine modification.