Experimental Investigations on DI Diesel Engine With Low Heat Rejection Combustion Chamber With Waste Fried Vegetable Oil and its Biodiesel

Biodiesels derived from vegetable oils present a very promising alternative fuels for diesel fuel, since they have numerous advantages compared to fossil fuels. However crude vegetable oil and biodiesel have high viscosity and low volatility causing combustion problems in CI engines, call for engine with hot combustion chamber. Investigations were carried out on single–cylinder, four–stroke, water cooled, 3.68 kW direct injection diesel engine at a speed of 1500 rpm to evaluate the performance of a engine with low heat rejection (LHR) combustion chamber. It consisted of an air gap (3 mm) insulated piston with superni (an alloy of nickel) crown and an air gap (3 mm) insulated liner with superni insert and ceramic coated cylinder head fuelled with different operating conditions (normal temperature and preheated temperature) of waste fried vegetable oil and its biodiesel with varied injection timing and injector opening pressure. Engine with LHR combustion chamber with biodiesel showed improved performance over conventional engine (CE) at 27° bTDC and at optimum injection timing. Biodiesel showed improved performance over crude vegetable oil with engine with both versions of the combustion chamber. Preheated test fuels and increase of injection pressure showed reduction of pollution levels and marginally improved performance over normal test fuels.