Effect of LPG Intake Temperature, Pilot Fuel and Injection Timing on the Combustion Characteristics and Emission of a LPG - Diesel Dual Fuel Engine

Dual fuel engines suffer from problems of poor brake thermal efficiency and high UBHC emission, particularly at low outputs. Pilot fuel quantity and the intake temperature are the two important parameters which control the combustion process in duel fuel engines. In the present experimental work, the effects of LPG intake temperature, pilot fuel quantity and injection timing, on improving the performance of LPG-Diesel dual fuel have been studied. The experiments were conducted on a computer interfaced LPG-Diesel duel fuel engine and the results have been analyzed. Results at 75% of load indicated that an ignition timing of 27° before TDC, gives low emission and high thermal efficiency. At higher LPG intake temperature UBHC and CO levels are low, and improvement in brake thermal efficiency were observed. A marginal increase in NOx level was found with increase in LPG intake temperature. At optimum conditions ie. 27° btdc injection timing, 0.45kg/hr pilot-fuel and at higher loads brake thermal efficiency was found to be higher by 5% compared to diesel mode of operation. Results have been shown that higher pilot -diesel quantity and elevated temperatures are advantageous