An Investigation of Cylinder Gas Motion in the Direct Injection Diesel Engine

In earlier papers presented to the Society of Automotive Engineers (1)*(2) the authors described the development of the gas flow pattern during the induction and compression strokes in direct injection diesel engines. Cylinder gas velocities were measured in motored engines using hot wire probes with compensation for variations in gas temperature. This technique is often considered more appropriate for the research laboratory than for industrial use and many engine manufacturers rely on steady flow testing of cylinder heads for assessing the swirl potential of new designs. In this paper the validity of the steady flow method of predicting swirl is examined.