Özet:

Aim: Investigations were carried out to evaluate the performance of a medium grade low heat rejection (LHR) diesel engine consisting of air gap insulated piston with 3-mm air gap, with superni (an alloy of nickel) crown and air gap insulated liner with superni insert with different operating conditions of raw jatropha oil with varied injection timing and injection pressure. The performance parameters of brake thermal efficiency (BTE), exhaust gas temperature (EGT) and volumetric efficiency (VE) were determined at various values of brake average effective pressure (BMEP). Methodology: Exhaust emissions of smoke and oxides of nitrogen (NOx) were recorded at different values of BMEP. Combustion characteristics of peak pressure (PP), time of occurrence of peak pressure (TOPP), maximum rate of pressure rise (MRPR) and time of occurrence of maximum rate of pressure (TOMRPR) were measured with TDC (top dead center) encoder, pressure transducer, console and special pressure-crank angle software package. Brief Results: Conventional engine (CE) showed deteriorated performance, while LHR engine showed improved performance with crude jatropha oil (CJO) operation when compared with pure diesel operation at recommended injection timing and pressure. The performance of both versions of the engine improved with advanced injection timing and higher injection pressure with test fuels. Peak brake thermal efficiency increased by 4%, volumetric efficiency decreased by 8%, smoke levels decreased by 4% and NOx levels increased by 37% with vegetable oil operation on LHR engine at its optimal injection timing, when compared with pure diesel operation on CE at manufacturer's recommended injection timing. Summary: Purpose: Research was conducted with 3 mm air gap, superni (nikel alloy), air gap isolated by shirt, superni addition, raw jatrofa oil's different working conditions, various injection times and injection pressure, to assess the performance of a medium low heat output diesel engine. Work Design: The performance parameters of the brake thermal effect (BTE), the exhaust gas temperature (EGT) and the volume effect (VE) are defined in the various values of the main brake active pressure (BMEP). Method: Nitrogen oxides and smoke emissions were recorded in the different values of BMEP. The highest pressure burning characteristics (PP), the highest pressure observation time (TOPP), the highest rate of pressure increase (MRPR) and the highest rate of pressure observation time (TOMRPR) were measured by the TDC (top dead point) coder, pressure converter, console and special pressure disease angle package software. Short results: The recommended injection time and pressure compared to the pure diesel work, the LHR engine has improved performance with raw jatrofa oil while the traditional engine (CE) has improved performance. The performance of both versions of the engine type was also developed with test fuels, high injection pressure and improved injection time. Compared with the manufacturer’s recommended injection time with pure diesel work on the LHR engine, its optimal injection time with vegetable oil operation increased the maximum brake heat efficiency by 4%, volume efficiency decreased by 8%, smoke levels decreased by 4%, nitrogen oxide levels increased by 37%.