Investigations on preheated palm oil methyl esters in the diesel engine

The major drawback of vegetable oil fuels is their high viscosity. Various conventional approaches to reducing the viscosity of vegetable oils are studied theoretically and experimentally. An attempt to reduce the viscosity of the palm oil methyl esters (POME) by preheating the fuel was performed and a comparison on the basis of its projected chance of leading to 'diesel-like' combustion was also carried out with conventional diesel fuel. It was observed that by preheating the POME fuel above the conventional temperature, the engine performance, especially the brake power output and the exhaust emissions characteristics, is improved significantly, approaching 'diesel-like' performance. This is mainly attributed to the fact that as the fuel is preheated the viscosity is reduced close to ordinary diesel (OD) fuel. This will result in improved spray and atomization characteristics. Torque, brake power, specific fuel consumption, exhaust emissions and brake thermal efficiencies were measured and calculated. The potential for improved engine performance and reduction in emissions levels was demonstrated.