Knock Modeling: an Integrated Tool for Detailed Chemistry and Engine Cycle Simulation

For the simultaneous evaluation of the influence on engine knock of both chemical conditions and global operating parameters, a combined tool was developed. Thus, a two-zone kinetic model for SI engine combustion calculation (Ignition) was implemented into an engine cycle simulation commercial code. The combined model predictions are compared with experimental data from a single-cylinder test engine. This shows that the model can accurately predict the knock onset and in-cylinder pressure and temperature for different lambda conditions, with and without EGR. The influence of nitric oxide amount from residual gas in relation with knock is further investigated. The created numerical tool represents a useful support for experimental measurements, reducing the number of tests required to assess the proper engine control strategies.