Numerical Simulation of the Progress of Chemical Reactions in a HCCI Engine

Authors

S. Hensel, W. Sauter, H. Kubach, A. Velji, U. Spicher, Institut für Kolbenmaschinen, Universität Karlsruhe (TH), A. Schubert, Ch. Hofrath, R. Schießl, U. Maas, Institut für Technische Thermodynamik, Universität Karlsruhe (TH)

Year

2007

Summary

The HCCI combustion in gasoline engines is a promising concept to reduce both emissions and fuel consumption at the same time. However HCCI operation is limited by steep pressure gradients at high loads and by decreasing operation stability at low loads. Because the spatial progress of the reactions can only be measured or described by extensive conventional measurement techniques or numeric tools, it is still not clear how the homogeneity of the charge can be used to minimise the pressure gradients or enhance the process stability. In this work simulations of a gasoline engine with HCCI combustion are shown. Based on a detailed reaction mechanism, an efficient model for treating the chemical reactions was developed and coupled with a CFD-Code. The results of experimental optical visualisation and of numerical simulation are compared and show good agreement. Hence the chemical model was used to investigate the influence of engine parameters on the spatial progress of the reactions in a HCCI engine.

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