Effect of Air Flow and Chamber Shape on Fuel Spray Configuration in a DI Diesel Engine.

Abstract

The requirements of meeting increasingly stringent emission regulations dictate increasing complexities in diesel engines and new thinking in the engine design. In this respect investigation of the diesel spray and mixture formation within the combustion chamber have attracted much attention. The diesel spray behavior has usually been investigated photographically in a pressurized vessel at ambient temperature. This paper presents the results of the fuel spray behavior for a modified direct injection diesel engine with a square piston of different combustion chambers. It was found that a strong squish affects the top side of spray significantly at early injection timings, higher engine speeds and narrow head clearances. The round lip in a reentrant type combustion chamber contributes to a better confinement of fuel and concave shape of the bottom surface helps the spray to reach to the air rich zone of the combustion chamber and mixture formation improves.