A New Coupling Approach Using a 1D System Simulation Software and a 3D Combustion Code Applied to Transient Engine Operation

Today's engine development concentrates mostly on steady state conditions to benchmark performance. In fact, the engine behaviour under transient operation is increasingly of interest due to the dynamic interactions between the engine sub-systems. Transient testing is however highly demanding and requires complex and sophisticated facilities.

This paper highlights an efficient way to investigate the transient engine behaviour using an original numerical approach based on the coupling between IFP-ENGINE, a 1D engine simulation tool, and IFP-C3D, a 3D combustion code. IFP-C3D is employed to extend or replace the experimental combustion maps used in IFP-ENGINE in the form of Wiebe's law. Basically, the process consists in first making the 3D in-cylinder combustion computations corresponding to all relevant engine operating conditions and then processing the combustion results via IFP-Combustion-Fitting, a specific tool that feeds IFP-ENGINE model with optimised Wiebe's law coefficients.

We first present the main tools as well as the coupling process. An application to the transient simulation of a turbo-charged gasoline direct injection engine is then proposed. The results of the numerical simulation are compared to the experimental results to demonstrate the predictability of this approach.