EXPERIMENTAL INVESTIGATIONS ON EXHAUST EMISSIONS INSULATED DIESEL ENGINE FUELLED WITH COTTONSEED BIODIESEL

Investigations were carried out to determine exhaust emission of a low grade low heat rejection (LHR) diesel engine with ceramic coated cylinder head [ceramic coating of thickness 500 microns was done on inside portion of cylinder head] with different operating conditions [normal temperature and pre-heated temperature] of cotton seed biodiesel with varied injector opening pressure and injection timing. Performance parameter [brake thermal efficiency] was evaluated at different values of brake mean effective pressure (BMEP) of the engine, while exhaust emissions [particulate emissions and nitrogen oxide (NOx) levels)] were measured at full load operation of the engine. Comparative studies were made with conventional engine (CE) with biodiesel and also with diesel operation working on similar operating conditions. Engine with LHR combustion chamber improved its performance when compared with CE with biodiesel operation. The optimum injection timing with CE with biodiesel was 31o bTDC (before top dead centre), while it was 30o bTDC for engine with LHR combustion chamber. Engine with LHR combustion chamber was more suitable for biodiesel operation rather than neat diesel operation. Engine with LHR combustion chamber at optimum injection timing of 30o bTDC with biodiesel operation increased peak brake thermal efficiency by 7%, at full load operation–decreased particulate emissions by 36% and increased NOx levels by 25% in comparison with CE with neat diesel operation at manufacturer's recommended injection timing of 27o bTDC.