2006 Volume 48 Issue 143 Pages 117-127
A multi dimensional model for the simulation of flow and combustion in combustion chamber was extended to knock calculation by coupling turbulence combustion model with simple chemical kinetics model. A Flamelet model proposed by Tahry that based on the probability of finding the flame and take into account of the strain rate has been implemented for the accurate prediction of flame propagation in homogeneous-charge turbulent pre-mixed combustion. A Shell model proposed by Halstead, modified to satisfy the principle of mass conservation and conservation of oxygen atom was used for knock calculation and combined with the Flamelet model to estimate the knock onset location and the timing. Visualizations were performed in order to verify the calculation accuracy for flame propagation and knock onset location. Flame propagation was visualized in an optical access engine, while knock detection was visualized in an actual engine. Moreover, the Effects of in cylinder flow on knock onset location were examined at different conditions such as tumble, reverse tumble and swirl flow field. The results confirmed that the calculations predicted flame propagation well. Simulation of the knock onset location was also shown to be possible. Applying this calculation to different in cylinder flow conditions, these were show that in cylinder flow affects knock onset location greatly. Furthermore, these calculations well agreed with experimental results.
