Effect of Injection Timing on Exhaust Emissions and Combustion Characteristics of Direct Injection Diesel Engine with Ceramic Coated Cylinder Head

Abstract

Experiments were carried out to study exhaust emissions and combustion characteristics of diesel engine with low heat rejection (LHR–1) combustion chamber consisting of conventional piston, conventional liner and ceramic coated cylinder head with neat diesel with varied injection timing. Combustion diagnosis was determined by using miniature Piezo electric pressure transducer and TDC (top dead centre) by using pressure-crank angle software package. Exhaust emissions of particulate levels and nitrogen oxide (NOx) levels were found out with varied brake mean effective pressure (BMEP), while combustion characteristics of peak pressure, time of occurrence of peak pressure and maximum rate of pressure rise are were determined at full load operation of both versions of the combustion chamber. The optimum injection timing was found to be 31obTDC (before top dead centre) with conventional engine, while it was 30o bTDC for engine with LHR–1combustion chamber with diesel operation. Engine with LHR–1 combustion chamber with neat diesel operation showed comparable particulate emissions and increase of NOxlevels at manufacturer’s recommended injection timing of 27obTDC, and the combustion characteristics improved marginally with advanced injection timing of 30obTDC in comparison with CE at 27obTDC.