Ecology, Environment and Conservation Paper

INVESTIGATIONS ON REDUCTION OF POLLUTANTS IN SPARKIGNITION ENGINE

Y. Nagini, M.V.S. Murali Krishna and S. Naga Sarada

Abstract

With a great vulnerability to oil embargoes and shortage of fossil fuels, attention is focussed ondevelopmentof alternative fuel sources. Therefore alternative fuels like alcohol are preferred due to their comparableproperties with gasoline. Reduction of exhaust emissions from engines has been focused and givenimportance in the development of new engines. The aim of the investigations is to determine and control ofpollutants of the variable speed engine with piston surface, coated with copper and also inner side of thecylinder head as well as liner fuelled with gasohol [80% of gasoline blended with 20% of ethanol] byvarying timing of spark ignition coupled with catalytic converter using catalyst of sponge iron incorporatingair injection in catalytic chamber. The operating conditions of the investigations were configuration of theengine and ignition timing, with and without the provision of catalytic chamber. The exhaust emissions ofcarbon mono oxide (CO), un-burnt hydro carbons (UBHC) and nitrogen oxide (NOx) levels were determinedat various values of brake mean effective pressure (BMEP) of the engine. CO emissions, UBHC emissionsand NOx levels were evaluated with sophisticated analyzer at various values of BMEP of theengine. Coppercoated engine with gasohol at its optimum ignition timing reduced pollution levels. Catalyticconverterreduced pollution levels by 40% and further reduction of emissions were pronounced with the injection ofair. 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).