Improving of Emissions and Performance of Rice Brawn Oil in Medium Grade Low Heat Rejection Diesel Engine

Abstract

Investigations were carried out to evaluate the performance of a medium grade low heat rejection (LHR) diesel engine with air gap insulated piston and air gap insulated liner with 3-mm air gap at different operating conditions [normal temperature and pre-heated temperature] of crude rice brawn oil (CRBO) with varied injection pressure and injection timing. Performance parameters of brake thermal efficiency, exhaust gas temperature, volumetric efficiency, coolant load and sound intensity were determined at various values of brake mean effective pressure (BMEP). Exhaust emissions of smoke and oxides of nitrogen (NOx) were recorded at various values of 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 deteriorated performance, while LHR engine showed improved performance with CRBO operation at recommended injection timing and pressure and 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 32 o bTDC for CE while it was 30 o bTDC with LHR engine with CRBO operation. Compatible performance in terms of peak brake thermal efficiency, exhaust gas temperature, coolant load, smoke levels were observed with LHR engine with CRBO operation at recommended injection timing of 27 o bTDC. (Before top dead centre) in comparison with pure diesel operation