Modeling of the Interaction of Intake Flow and Fuel Spray in DISI Engines 2000-01-0656
The interaction between in-cylinder flow and injected fuel spray in direct ignition spark ignition (DISI) engines have been investigated. The study shows that the major effect of intake flow on the fuel spray is that the induced flow tends to make the spray collapse. This deformation of spray will prevent the fuel spray from spreading out, evaporating, and mixing well with air and also increase fuel wetting on the wall. It has been demonstrated that the intake flow effect on the fuel spray can be alleviated by increasing the masking between the two intake ports. Swirl and tumble motion effects on the fuel air mixing and wall wetting in DISI engines were also studied. A counter-rotating vortex structure is identified in the case with tumble dominating in-cylinder flow structure. This vortex structure tends to hinder fuel air mixing and increase wall wetting. It is shown that some swirl motion is helpful to improve mixing quality and decrease the wall wetting.