The Importance of Turbulence and Initial Flame Kernel Center Position on the Cyclic Combustion Variations for Spark-Ignition Engine 961969

This paper investigates the effects of the variations of turbulence characteristics and initial flame kernel center position on the cyclic combustion variations by means of quasi-dimensional turbulent entrainment combustion model. The turbulence intensity and turbulence integral length scale at spark ignition time in the model are determined by maximizing the agreement between the predicted and measured results such as pressure diagrams, mass fraction burned etc. With different values of the turbulence intensity and turbulence integral length scale at spark ignition time, the calculation of the cyclic combustion variations for the engine is carried out. In addition, the prediction of the effect of different flame kernel center positions on the cyclic combustion variations is also studied. Finally, some conclusions are drawn out about the importance of turbulence and initial flame kernel center position on the cyclic combustion variations for spark-ignition engine.