Modeling of auto ignition combustion with inhomogeneous mixture

Abstract

To predict the combustion characteristic of auto ignition combustion in internal combustion engines, it is necessary to consider the inhomogeneity of the fuel, EGR and air in the mixture. In this research, a PDF (Probability Density Function) combustion model considering the influence of the inhomogeneity of mixture on the auto ignition combustion is developed. In our approach, the PDF of the injected fuel and the EGR gas is predicted by two-zone turbulent mixing model and only the PDF at the top dead center of the combustion stroke is used to calculate combustion characteristic to realize the reasonable calculation time for the control system design tool. The prediction model was validated by comparing with the experimental result for various injection timings and EGR ratios. It found that the model can qualitatively predict the combustion characteristics with reasonable calculation time.