Abstract
Jatropha Curcas L. can produce a great source of biofuels which can be used on diesel engine as new supplier for the new biofuels source and it can be substituted for edible oil, especially Palm oil. Jatropha Curcas L. is a drought resistant species which is widely cultivated in the tropics; the crop grows as scrub, and often use as living fence. Furthermore, Jatropha Curcas L.oil can be used to develop domestic economy in rural areas. Jatropha Curcas oil (viscosity and pour point) has some chemical properties which are better than those of palm oil when it is applied for diesel engine. Experiments were carried out on a direct injection diesel engine with standard gas-oil and various Jatropha Curcas L.oils. These Jatropha Curcas L.oils included of crude oil, degummed oil and fatty acid methyl ester oil. The combustion processes of these fuels were diagnosed by using heat release rate and exhaust gas emission. The results of Jatropha Curcas L.oils were compared to the results of standard gas-oil. The results indicated that Jatropha Curcas L. crude oil has longest ignition delay and highest exhaust gas emissions of CO, HC and Smoke in comnarison with other tested fnels due to low Cetane index high viscosity and high Phosphorus content. The degumming process was used to reduce the Phosphorus content in Jatropha Curcas crude oil. However, the ignition delay was still much longer than standard gas-oil due to the low cetane index and high viscosity. For blended fuel, 10 % degummed Jatropha Curcas oil and 90 % gas-oil, the exhaust gas emission CO, NO_x had almost the same concentration and slightly lower HC emission in comparison with standard gas-oil. In case of fatty acid methyl ester, the ignition delay was shorter than gas-oil oil due to the higher cetane index along with small content of oxygen in fuel. The using of fatty acid methyl ester was reduced not only CO, HC smoke but also NO_x emission.
