Indiscriminate extraction and lavish consumption of fossil fuels have led to reduction in underground based carbon resources. The search for an alternative fuel, which promises a harmonious correlation with sustainable development, energy conservation, management, efficiency and environmental preservation, has become highly pronounced from the refined edible vegetable oil such as Jatropha seed oil by alkaline catalyzed transesterification process. In the study reported herein, Jatropha oil was used as raw oil to produce biodiesel by transesterification reaction accompanied by peroxidation to further improve the fuel properties of the biodiesel. By means of high- speed mechanical homogenizer, the biodiesel product was then emulisified with distilled water and emulsifying surfactant to produce a three phase oil droplets in- water- droplets- in-oil(ie.O/W/O) biodiesel emulsion and an O/W/O emulsion that contained aqeous ammonia, which is a NO_x inhibitor agent. The prepared biodiesel was then subjected to performance and emission tests in order to evaluate its actual performance, when used as a diesel engine fuel. Asingle cylinder direct injection diesel engine was used for this work to investigate the engine performance and emission characteristics of the biodiesel, the O/W/O biodiesel emulsion, the O/W/O biodiesel emulsion that contained aqeous ammonia. The brake specifc fuel consumption (BSFC) and brake thermal efficiency (BTE) were calculated from the recorded data. Moreover, the existence of aqeous ammonia in the O/W/O biodiesel emulsion curtails NO_x formation, thus resulting in the lowest NO_x emissions among the four tested fuels in burning the O/W/O biodiesel emulsion that contained aqeous ammonia.

Keywords: Biodiesel; Esterification; Engine performance; Emulsion; peroxidation process.