Multidimensional Modelling of Knocking Combustion in SI Engines

A two-dimensional model for the simulation of flow and premixed combustion in engines is extended to include a knock sub-model. An autoignition model based upon a degenerately branched chain mechanism /14/ was modified for this purpose. Rapid-compression machine experiments could be reproduced as well as engine knocking tendencies. The coexistence of the new knock model and the overall combustion model of Arrhenius type was arranged by a suitable switch-off criterion for the autoignition reactions. Simulation of pressure waves and respective flowfields under knocking conditions are also shown to be possible. A parametric study of the influence of engine geometry, EGR and swirl on knocking tendency is presented.