STUDIES ON THE INFLUENCE OF CHARGE NON-HOMOGENEITY ON CYCLE-BY-CYCLE VARIATIONS IN COMBUSTION AND NITROGEN OXIDES EMISSIONS IN SI ENGINES

Abstract

Cycle-by-Cycle combustion variations in spark ignition engines have been known to exist for many years. A compre-hensive literature survey showed that very little information is available on the quantitative relationship of in-cylinder charge non-homogeneity yith combustion variations, even thO.ugh the charge inside the combustion chamber of liquid-fueled spark ignition engines is not expected to be entirely homogeneous. Secondly, not much data exists on the influence of such unorganized charge non-homogeneity on exhaust emissions. in the present study, an attempt has been made to investigate the dependence of combustion variations and the emissions of nitrogen oxides on in-cylinder charge non-homogeneity. The charge non-homogeneity was determined experimentally from the measured exhaust gas composition, using Eltinge's technique (69). This technique was also extended for application to alcohols. An on-line high speed data acquisition system, DIGITAP was used for the determination of cyclic variations in peak combustion pressure and the angle of its occurrence and other related Statistics.