Abstract
A novel 0-Dimensional cycle engine simulation has been developed through a series of our studies. For a whole range of operating conditions, it can predict well the engine performances such as torque, combustion noise, NOx emission, and so on. In that simulation, heat transfer through engine cylinder was evaluated by Woschni equation, which has been widely used in a general 0-D simulation. However it is questionable regarding the prediction accuracy because in-cylinder flow motion and fuel spray flow along the wall were not directly considered in that equation, although both of them have crucial impacts on heat transfer phenomena. In this study, the effect of in-cylinder flow on the heat transfer has been modeled based on the theory of plane turbulent boundary layer. In addition, the effect of wall-impingement of burning spray has been modeled by the similar formulation considering spray jet motion. Comparisons of results of 3-Dimensional simulation employing a precise heat transfer model reveal that the proposed models can well reproduce heat transfer process against varied fuel quantities, in spite of simple 0-D simulation. Resultantly, the effect of raised injection pressure on fuel economy can be also predicted well compared with measurement.
