Assessment of emission and performance of compression ignition engine with varying injection timing

Engine performance improvement and exhaust emissions reduction are the two most important issues to develop a more efficient engine with less environmental impact. For a diesel engine, injection timing is one of the major parameters that affect the engine performance and emissions. Now-a-days, alternative fuels for internal combustion engines have created interest among the researchers around the world due to the limited reserve and rapid depletion of petroleum based fuels. In this paper, studies focused on characterizing influence of injection timing on engine performance and exhaust emissions have been critically reviewed where diesel, biodiesel, alcohol and other alternative fuels are used. In case of diesel fuel, advancement in injection timing results in lower carbon monoxide (CO) and hydrocarbon (HC) emission; though it increases nitrogen oxides (NOx) emission. Advance injection timing increases brake thermal efficiency (BTE) and decreases brake specific fuel consumption (BSFC). Biodiesel-diesel blends produce more HC and CO emission, but reduce NOx emission when injection timing is retarded. Advancement in injection timing results in higher exhaust gas temperature with increase of biodiesel percentage in the blends