Properties Modification of Crude Jatropha Oil for Utilization as Fuel in Direct Injection Diesel Engine

Abstract

Renewable energy sources from plant appeared to be an alternative source of fuel for diesel engine. Jatropha oil is one of the promising alternative choices. The aim of this research is to study the effect of modification of Jatropha oil fuel properties on direct injection diesel engine performance and exhaust emissions. Modification of Jatropha oil fuel properties such as transesterification process to produce biodiesel, addition of water to produce emulsion fuel and blended with diesel fuel have been conducted. However, due to high free fatty acid contents of Jatropha oil, transesterification process alone is unable to produce Jatropha biodiesel and this fuel has been omitted as test fuel from this study. The engine performance and exhaust emissions of 20% of Jatropha oil blends with diesel fuel (J20), and Jatropha emulsion fuel (J20 Emul) are measured and has been compared with conventional diesel fuel. A 600cc single cylinder direct injection diesel engine was used. The experiment was conducted at 1500rpm with variable engine loads. The results indicated that J20 Emul showed the highest brake thermal efficiency. There is no significant difference of brake thermal efficiency produced by J20 and diesel fuel. Brake specific fuel consumption (BSFC) for J20 Emul is the lowest at low load and do not exhibit much difference with other test fuel at high loads. For the exhaust emissions, J20 Emul produced lowest emission of nitrogen oxide (NOx) and smoke number while diesel fuel produced the highest smoke number for all loads and emission of NOx for low loads. J20 on the other hand, showed the highest NOx emission at high loads. For the emission of carbon monoxide (CO), both J20 Emul and J20 show slight increment compared with diesel fuel.