INFLUENCE OF TURBULENCE AFFECTING PARAMETERS ON THE PERFORMANCE OF I C ENGINES

Abstract

For many years, engine designers have sought means of improving the power and economy of their engines. Large improvements in the engine efficiencies have been realised by increasing the compression ratio, improving the ignition system etc. Additional improvements must now come from the advances in new areas of the engine-fuel relationship. At present one of the most serious blocks to an increased economy of fuel is the unsteady power on output of the engine. This unsteady power output is a result of the fact that the combustion is not the same from one cycle to another. This combustion variation is believed to be reduced by increasing the intensity of turbulence and swirl, in the neighbourhood of the spark plug, during combustion. Keeping this fact in mind various modifications were made in the inlet system and their effects on the engine performance with respect to the exhaust gas analysis, _11E54 the thermal efficiencies cyclic variations in peak pressure was studied, The modifications studied included the various range type, shrouded inlet valves and the inb]_usion of wire-mesh of various sizes in the inlet manifold. The major conclusibn is that the direction of the incoming flow and the intensity of turbulence and swirl in the charge at the time of cambustion'is an important factor in leading to a better and steadier combustion. Although, in our experiments with ,9R engine the shrouded valve gave the best performance, the vane type valves could give equally good or even better performance if a proper number of vanes with proper inclination are used.