Diesel Piston Bowl Optimization

Today‘s car manufacturers inevitably have to focus on the reduction of fuel consumption while maintaining high performance standards. In this respect, turbocharged direct injection diesel engines represent an appealing solution. The challenge in developing these engines is – in addition to above-mentioned reduction of fuel consumption and high performance standards – the reduction of raw emissions. Both, fuel consumption and emission formation can be addressed by internal engine measures.

In the virtual development of future engine combustion processes 3D-CFD is an important tool. Hereby, the in-cylinder flow, the internal mixture formation and combustion as well as emission formation can be investigated.

The diesel engine combustion process is determined, besides flow induced by the intake ports, by fuel injection process and bowl shape. Small changes of the bowl geometry can lead to a significant improvement of mixture formation and thus reduced emission formation. For optimization of the bowl shape CAESES is used and coupled to the 3D-CFD software to evaluate designs in an automatic loop. Thereby, CAESES provides parametric models which are transferred to 3D-CFD software via a software connector. For each variant, the compression volume is kept constant by CAESES.

An optimizer analyses the results and creates new parameters as input for CAESES. The resulting bowl shapes are characterized by improved fuel consumption as well as low raw emissions.