Effect of Ethanol Fumigation on Performance and Combustion Characteristics of Compression Ignition Engine Fuelled with Used Cooking Oil Methyl Ester in Dual-Fuel Mode

Exhaustion of crude oil reserves, increasing energy demand, drastic changes in weather conditions due to engine tail pipe emissions, stringent emission norms have induced the researchers for the search of biofuels. Methyl esters derived from used cooking oil (UCO) have properties closer to diesel fuel are considered as an ideal alternative fuel for compression ignition engine (CI engine). The present paper is to investigate the performance and combustion properties of single cylinder CI engine fuelled with used cooking oil methyl ester (UCOME) as the main fuel that is injected inside the cylinder and ethanol as a secondary fuel injected in the intake manifold by an electronic fuel injector which is controlled by ECU. Ethanol is injected at different mass flow rates of 0.1, 0.15 and 0.25 kg/h. It is observed that UCOME+E3 shows higher brake thermal efficiency (BTE) compared to other ethanol flow rates because of better combustion and air–ethanol blend quality in high engine loads. The brake-specific fuel consumption (BSFC) for ethanol fumigated with UCOME fuels has been reduced at higher loads as compared with neat UCOME fuel. Ethanol’s flame spread is higher, which increases the rate of change of pressure and increases in-cylinder pressure values. The values of heat release rate (HRR) have been found increased due to high oxygen content in ethanol.