Influence of the Relative Motions of Air and Fuel Vapor on the Mixture Formation Processes of the Direct Injection Diesel Engine

Investigations on the relative motion between fuel spray and air in a DI diesel combustion chamber were made on a single cylinder engine with help of the high speed Schlierenfilm technique.

The relative motion was varied by changing the air swirl velocity on the one hand and by changing the fuel jet velocity on the other hand. The effect of these different cases of mixture formation and heat release on fuel economy, pressure rise, HC-, CO-, NO- and soot emissions was studied on a single cylinder engine with a central 4-hole nozzle.