Numerical study of the interchanging vapor, droplet, and film flows in a gasoline engine manifold

In gasoline engines, fuel may be introduced in a number of different ways, including upstream manifold injection at one or two points using either carburetors or throttle-body injectors, port injection or in-cylinder injection. The last is essentially experimental and used in stratified charge engines. The characteristics of the flow during acceleration/deceleration transients require investigation because of the lag effects related to the fuel reaching the engine from its point of injection. This paper deals with a numerical model of a single-point system in an unbranched manifold with specific consideration of the requirements necessary for studying the liquid/vapor fuel proportions entering the cylinder, and the behavior during transient operation.