Experimental investigations on pollution levels of low heat rejection diesel engine with varied air gap thickness

ABSTRACT Conservation of fossil fuels is gaining momentum along with adapting alternative fuel technology methods for the researchers and manufacturers involved in combustion research. The concept of low heat rejection (LHR) engine is to minimize heat flow to the coolant by providing thermal resistance in the path of heat flow to the coolant and thus increase thermal efficiency. It has significant characteristics of higher operating temperature, maximum heat release, and ability to handle low calorific value fuel. Investigations were carried out to determine exhaust emissions of diesel engine withair gap insulated low heat rejection (LHR–3) engine consisting of air gap insulated piston with superni crown, air gap insulated liner with superni insert and ceramic coated cylinder head with neat diesel with varied air gap thickness and injection timing. Exhaust emission of particulate emissions and nitrogen oxide levels were determined at various values of brake power.The optimum air gap thickness was found to be 2.8 mm withLHR–3engine with diesel operation.LHR engine with neat diesel operation showed deteriorated performance at manufacturer's recommended injection timing of27o bTDC (before top dead center) in comparison with CE.Exhaust emissions reduced with advanced injection timing of 28.5obTDC with LHR engine in comparison withsame configuration of the engine at 27obTDC.