IMPROVEMENT OF PERFORMANCE AND EMISSION CHARACTERISTICS OF A DI DIESEL ENGINE WITH TURBULENCE INDUCED PISTON (INTERNAL JET PISTON) USING BIODIESEL BLENDS

Biodiesel derived from vegetable oil are quite promising alternative fuels for diesel engines, because of their low environmental impact and has potential as an alternative fuel for diesel engine without any modification on the engine Use of vegetable oils in diesel engines leads to slightly inferior performance and higher smoke emissions due to their high viscosity. The performance of vegetable oils can be improved by modifying them through the transesterification process. In this study, an attempt is made to investigate the influence of turbulence inducement using internal jets in a Direct Injection (DI) diesel engine combustion chamber with diesel and palm oil methyl ester (POME). The turbulence in engine cylinder is induced by providing internal jets on the piston crown, located diametrically opposite on the piston crown. The working fluid has a tangential entry into the bowl through these holes. For these changes the performance and emission characteristics are measured and evaluated on single cylinder water cooled direct injection diesel engine.

The experimental results concerning performance and emission characteristics of the engine from no load to full load condition is analyzed. The brake thermal efficiency for 20 % POME was found to be increased by 2.5% at full load conditions for internal jet piston than base engine with biodiesel blends. The NOx emissions were increased by 15 %, unburned hydro carbon and smoke emissions were decreased by 40 % and 35% respectively and 32 % reduction in CO emissions for 20 % POME with internal jet piston compared to base engine with biodiesel blends due to complete combustion of fuel with turbulence inducement by the internal jets in the combustion chamber.