Experimental studies on the performance and emission characteristics of a compression ignition engine fuelled with jatropha oil methyl ester

Abstract

In this work, biodiesel obtained from jatropha seeds are used as alternative fuel to diesel in stationary diesel engines. The oil obtained from the jatropha seeds are trans-esterified to get biodiesel. The biodiesel obtained has good ignition ability due to its relatively high cetane number compared to that of conventional diesel fuel. The oxygen component in the biodiesel fuel has the effect of reducing the pollutant concentration in exhaust gases due to better burning of the fuel in the engine. But the viscosity of biodiesel is very high compared to diesel and this affects its atomization and penetration characteristics and hence it is blended with diesel while being used as an alternate fuel in diesel engines. Performance and emission tests of Jatropha Oil Methyl Ester (JOME) and their blends (80%, 60%, 40%, 20%) with diesel were carried out on a direct injection compression ignition engine at constant speed and at variable load conditions. The experimental results show that all the blends can be used as fuels for diesel engine without any major modification in the engines. It is also seen that the carbon monoxide, unburnt hydrocarbon and soot emissions are less at all loads for the blends compared to diesel fuel while oxides of nitrogen emissions are slightly higher. Tradeoff between oxides of nitrogen and soot emissions for various percentage of JOME in blends show that 19% of JOME blend are observed to be optimum considering both NOx and soot emissions. At the rated power output (4.4 kW) the NOx emissions are 7.46 g/kWh and the soot emissions are 120 mg/m3 for 19% JOME compared with diesel the NOx emissions are 7.25 g/kWh and the soot emissions are 166 mg/m3.

Keywords

• biodiesel
• jatrophaoil methyl ester
• emission analysis
• compression ignition engine
• optimum blend