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In this paper, we present simulations of one dimensional stratified charge combustion. Our initial simulations are based on the experiments of Moriyoshi et al. [1]. In agreement with their experiments, our results show that the degree of stratification significantly affects the combustion process, and that incorporation in a stratified system causes mixtures to burn which would not burn in a homogeneous charge situation. For example, a lean mixture with an equivalence ratio of 0.4 will burn when stratified with a mixture of equivalence ratio 1.0. We also demonstrate how tailoring the stratification can improve the combustion characteristics.

Multi-dimensional numerical simulation of the combustion process in spark ignition engines were performed using the Coherent Flame Model (CFM) which is based on the flamelet assumption. The CFM uses a balance equation for the flame surface area to simulate flame surface advection, diffusion, production and destruction in a turbulent reacting flow. There are two model constants in CFM, one associated with the modeling of flame surface production and the other with the modeling of flame surface destruction. Previous experimental results on two test engines charged with propane-air mixtures were used to compare with the computations for different engine speeds, loads, equivalence ratios and spark plug locations. Predicted engine cylinder pressure histories agree well with the experimental results for various operating conditions after the model constants were calibrated against a reference operating condition.