The Combustion Process in Swirl Chamber Type Diesel Engines

Abstract

High-speed motion pictures taken through glass windows in a full-scale engine, have led to the following knowledge about the combustion process in a swirl chamber type Diesel engine. The gas in the swirl chamber rotates in the same direction throughout the combustion and, after ignition, flows out into the main chamber from its periphery, layer by layer. The fuel-air distribution in the swirl chamber, which depends primarily on the direction of fuel injection, has a predominant influence on the subsequent combustion process. In the case of fuel injection along the air-swirl, the formation of an overrich mixture in the peripheral zone brings about two favorable factors for a rapid and complete combustion ; one is the possibility of an earlier outflow of the mixture into the main chamber, and the other is the most effective use of thermal mixing effect in the swirl chamber. In addition, these factors were discussed in relation to the performance of a practical engine.