Experimental Investigation of Cyclic Variation of Combustion Parameters in a Catalytically Activated Two Stroke SI Engine Combustion Chamber

This paper presents the results of experimental work conducted on a catalytically activated two stroke spark ignited engine, to investigate the cyclic variation of combustion parameters. A comparative study was carried out with the base engine for finding out the effect of catalytic activation. The catalyst selected was copper and coated on the inside surface of combustion chamber walls and piston crown by plasma spraying technique. Cylinder pressures were recorded for 2000 continuous cycles using a piezoelectric pressure pickup and PC based data acquisition system. The covariance (COV) were calculated for the 2000 cycles and compared with base engine. The results show that the catalyst coating accelerates the pre-flame reaction and shortens the combustion duration. The cyclic variation of combustion parameters were less than the base engine and there is a group of cycles which deviate from the normal cycles. This deviation was in the upper side leading to higher mean values of peak pressures. But this does not affect the smooth running of the engine and COV of crank shaft speed was similar to that of base engine.