Towards a Universal Combustion Model in STAR-CD for IC Engines : From GDI to HCCI and Application to DI Diesel Combustion Optimization

Gasoline Direct Injection (GDI) appears to be the most relevant way to improve fuel efficiency of SI engines. Homogeneous Charge Compression Ignition (HCCI) has also emerged as a viable alternative combustion process for Spark Ignited (SI) and Compression Ignited (CI) engines. The development of such engines is difficult. Every parameter, such as piston shape, injector inclination, or mixing process for example, has to be carefully adapted. CFD is a useful tool to understand the processes taking place in the combustion chamber and the correlation between parameters and, therefore, a way to support the design. However, CFD will require specific sub-models able to describe the spray and its evaporation, the mixing process and stratification, and the combustion process including auto-ignition.