World Renewable Energy Congress VIII: Book of Abstracts

For countries, which produce oil crops, vegetable oil is a potential source of alternative fuel. Over the years there have been many attempts to use various types of vegetable oil directly in diesel engines. These include palm oil, soybean oil, sunflower oil, safflower oil, coconut oil, rapeseed oil, jatropha oil etc. Crude Palm Oil (CPO) is one of the promising renewable bio-fuels. Many researchers have reported of successful short-term trials with this particular vegetable oil. However, long-term tests revealed degraded engine performance and problems such as deposit build up in the combustion chamber, injector coking, piston ring sticking and lubrication oil dilution. In the present research, a Yanmar L60AE single cylinder direct injection diesel engine was coupled to an electric dynamometer to provide load. The engine was run at a constant speed of 3600 r/min. Pressure transducer was used to measure the in-cylinder pressure while other instruments were available to determine fuel flow rate, ambient temperature and exhaust temperature. The engine was started with diesel fuel only and switched to CPO after the engine was warmed up. Despite the higher viscosity at 60°C, the ignition delay was found to be shorter for CPO than that of diesel, thus producing less intensive premix combustion. This was probably due to chemical reactions of CPO during the injection period. Breaking of the double bond carbon chain produce lighter volatile compound, leading to shorter ignition delay. Combustion analysis revealed that combustion of CPO reached a higher peak pressure at earlier crank angle and lower premix combustion than diesel. It was found that with CPO brake thermal efficiency was comparable to that of diesel, however, specific fuel consumption was higher, due to lower calorific value of CPO. In term of emission, relative to diesel engine CPO produces higher CO but comparable NO emission. * Tel: +618 8302 3439, Fax: +618 8302 3380, email: [email protected] (S. Bari) Biomass Conversion