COMPARATIVE STUDIES ON PERFORMANCE AND EMISSIONS OF TWO STROKE AND FOUR STROKE COPPER COATED SPARK IGNITION ENGINES WITH METHANOL BLENDED GASOLINE

摘要

Investigations were carried out to evaluate the performance of two stroke and four stroke of single cylinder, spark ignition (SI) engines having copper coated engine [CCE, copper-(thickness, 300 μ)] coated on piston crown and inner side of cylinder head] provided with catalytic converter with sponge iron as catalyst with methanol blended gasoline (80% gasoline and 20% methanol by volume) and compared with conventional engine (CE) with pure gasoline operation. Performance parameters- brake thermal efficiency (BTE), exhaust gas temperature (EGT), volumetric efficiency and exhaust emissions of carbon monoxide (CO) and un-burnt hydrocarbon (UBHC) were determined with different values of brake mean effective pressure (BMEP) of the engine and compared with one over the other of two stroke and four stroke SI engine with different versions of the engine. Formaldehyde and acetaldehyde emissions were measured by 2, 4 dinitrophenyl hydrazine (2,4 DNPH) method at peak load operation of CE and CCE of two-stroke and four-stroke SI engine. The engine was provided with catalytic converter with sponge iron as catalyst. There was provision for injection of air into the catalytic converter. Brake thermal efficiency increased with methanol blended gasoline with both versions of the engine. CCE showed improvement in the performance when compared with CE with both test fuels. Four-stroke engine decreased exhaust emissions effectively in comparison with two-stroke engine with both versions of the engine. Catalytic converter with air injection significantly reduced exhaust emissions with different test fuels on both configurations of the engine.