The Development of an Ignition and Combustion Model for Direct Injection Spark Ignition Engine Simulations

摘要

An improved spark ignition model has been developed and implemented into the KIVA-3V code. In this model, the spark ignition kernel growth is tracked by Lagrangian particle markers. The effects of turbulent flow and spark discharge energy on the kernel growth are considered. After the ignition kernel size exceeds a critical size related to the integral turbulent length scale of the flow, the turbulent flame is considered to be fully developed. A G-equation model is used to track the mean turbulent flame evolution. By ignoring the detailed turbulent flame brush structure, fine numerical resolution is not required, thus making the model suitable for use in multidimensional simulations of SI engines. Combined with a characteristic time scale combustion model, the models were used to simulate the ignition and combustion processes of a small marine DISI two-stroke engine that features two-spark plugs, where the triple flame structure must be considered. The evolution of the two spark kernels and turbulent flames starting from the two spark plugs are modeled. Good agreements with measured cylinder pressure was also obtained.