Investigations on reduction of pollutants in spark ignition engine

With a great vulnerability to oil embargoes and shortage of fossil fuels, attention is focussed on development of alternative fuel sources. Therefore alternative fuels like alcohol are preferred due to their comparable properties with gasoline. Reduction of exhaust emissions from engines has been focused and given importance in the development of new engines. The aim of the investigations is to determine and control of pollutants of the variable speed engine with piston surface, coated with copper and also inner side of the cylinder head as well as liner fuelled with gasohol [80% of gasoline blended with 20% of ethanol] by varying timing of spark ignition coupled with catalytic converter using catalyst of sponge iron incorporating air injection in catalytic chamber. The operating conditions of the investigations were configuration of the engine and ignition timing, with and without the provision of catalytic chamber. The exhaust emissions of carbon mono oxide (CO), un-burnt hydro carbons (UBHC) and nitrogen oxide (NOx) levels were determined at various values of brake mean effective pressure (BMEP) of the engine. CO emissions, UBHC emissions and NOx levels were evaluated with sophisticated analyzer at various values of BMEP of the engine. Copper coated engine with gasohol at its optimum ignition timing reduced pollution levels. Catalytic converter reduced pollution levels by 40% and further reduction of emissions were pronounced with the injection of air. The ignition timing which was found to be optimum with CE was 280bTDC (before top dead centre), while it was 270b TDC with copper coated engine (CCE).