AN EXPERIMENTAL STUDY ON THE EFFECT OF ENGINE SPEED VARIATION ON PREMIXED RATIO, EQUIVALENCE RATIO AND EMISSIONS OF DUAL FUEL HCCI ENGINE

In this study, effect of engine speed variation on premixed ratio, equivalence ratio and emissions of a dual fuel HCCI engine are investigated. The experiments were conducted on a variable compression ratio (VCR) single-cylinder research engine with compression ratio of 17.5:1. Premixed gasoline was introduced to inlet manifold through a carburetor which is equipped with a needle screw to adjust the gasoline mass flow rate. Results show that the CO, HC and soot emissions increases by increasing the engine speed due to less hornogeneity in the mixture and decreasing the overall reactivity, also the premixed fuel and therefore the equivalence ratio increases as a result of engine speed increase in HCCI combustion.