Fuel Injection and Combustion in the Swirl Chamber of a Diesel Engine

Abstract

The state of air-swirl, mixture formation and combustion in the swirl chamber of a Diesel engine was studied through a glass window by using the high-speed photograthy. The air in a swirl chamber rotates in the same direction throughout the combustion. After ignition, gas flows out into a cylinder from its periphery, layer by layer. The boundary of fuel spray is blown off and the core is bent by the strong swirl. However, the distribution of fuel in a swirl chamber is mainly settled by the direction of fuel injection : 1) The fuel injected against the swirl is concentrated near the center of the chamber and remains there throughout the combustion, thereby causing soot formation. 2) In the case of fuel injection along the swirl, rich mixture forms in the peripheral layer, flows out rapidly into a cylinder and mixes there with air, thus burning up completely.