Experimental investigation and exergy analysis of a homogeneous charge compression ignition engine fueled with natural gas and diethyl ether and a dual fuel engine

Abstract

Recent stringent emission norms and the deterioration of petroleum fuels seek alternative fuels or alternative designs for efficient internal combustion engines. The direct injection diesel engine gives good thermal efficiency and low HC emissions. But, due to its higher emissions of particulate matter and NOx emissions, it fails to meet the required emission standards when it is operated without after-treatment devices. After treatment devices are costly and create back pressure leading to diminishment in performance. Therefore, either alternative methods like boosting the intake pressure, exhaust gas re-circulation, pre-chamber, and variable valve timing can be employed in the diesel engine or the modified form of compression ignition engines like dual-fuel engines, homogeneous charged compression ignition engines, and premixed charge ignition engines can be used to reduce the harmful emissions. But, the reduction in NOx emissions leads to a reduction of brake thermal efficiency except in Homogeneous Charge Compression Ignition engine (HCCI engine). newlineThe gaseous fuels can be used in the diesel engine with a small quantity of pilot diesel fuel injection. But, the small quantity of pilot fuel is not sufficient for the complete combustion of the air-fuel mixture. This tends to increase the HC emissions. Therefore, the intake charge preheating would support in the reduction of the HC emissions. At full load operation, because of disassociation due to high heat release NOx and CO emissions are increased due to preheating in the dual fuel engine. But, use of gaseous fuel in HCCI engine has tendency to produce less NOx emissions with high thermal efficiency because of shorter spontaneous combustion of the premixed mixture. newline