Air motion in a four-stroke direct-injection diesel engine

The investigation presented attempts to develop a suitable mathematical model which may be relied upon to predict the air motion within the cylinder of a motored, four-stroke direct-injection diesel engine. Using a method of hot wire anemometry, a three-wire anemometer was developed for measuring the magnitude and direction of the three-dimensional velocity vector within a variable density flow similar to that encountered inside a motored engine cylinder and an exhaustive experimental program undertaken to justify the technique. The results of the experimental program showed that the magnitude of, the. Three-dimensional velocity vector may be measured within an accuracy of ± 9% whilst the direction may be determined within ± 12%. Applying the method to an engine cylinder, measurements of the air motion were recorded over a range of engine speeds (500–1500 rpm) and the effect of a masked inlet valve and supercharging the engine at 10 psig were also investigated. [Continues.]