Performance Evaluation of a Medium Grade Low Heat Rejection Diesel Engine with Mohr Oil Based Bio-Diesel (original) (raw)

Investigations were carried out to evaluate the performance of a low heat rejection (LHR) diesel engine with air gap insulated piston with superni (an alloy of nickel) and air gap insulated liner with different operating conditions [normal temperature and pre-heated temperature] of mohr oil based bio-diesel (MOBD) with varied injection pressure and injection timing. Performance parameters and exhaust emissions of smoke and oxides of nitrogen (NOx) were determined at different magnitudes of brake mean effective pressure (BMEP). Combustion characteristics at peak load operation of the engine were measured with TDC (top dead centre) encoder, pressure transducer, console and special pressure-crank angle software package. Conventional engine (CE) showed marginal improvement in performance with biodiesel operation, while LHR engine showed improved performance at recommended injection timing of 27 o bTDC (before top dead centre) and recommended injection pressure of 190 bar. The performance of both version of the engine improved with advanced injection timing and at higher injection pressure when compared with CE with pure diesel operation. The optimum injection timing was 33 o bTDC for CE while it was 31 o bTDC with LHR engine with biodiesel operation. Peak brake thermal efficiency increased by 12.5%, smoke levels decreased by 48% and NOx levels increased by 35% with MOBD operation on LHR engine at its optimum injection timing, when compared with pure diesel operation on CE at 27 o bTDC.