Grasreiner S. Combustion modeling for virtual SI engine calibration with the help of 0D/3D methods

Dissertation zur Erlangung des akademischen Grades Doktor-Ingenieur (Dr.-Ing.). — Freiberg: Von der Fakultät für Maschinenbau, Verfahrens- und Energietechnik der Technischen Universität Bergakademie Freiberg genehmigte, 2012. — 179 p.Abstract.
Spark ignited engines are still important for conventional as well as for hybrid power trains and are thus objective to optimization. Today a lot of functionalities arise from software solutions, which have to be calibrated. Modern engine technologies provide an extensive variability considering their valve train, fuel injection and load control.
Thus, calibration efforts are really high and shall be reduced by introduction of virtual methods.
In this work a physical 0D combustion model is set up, which can cope with a new generation of spark ignition engines. Therefore, at first cylinder thermodynamics are modeled and validated in the whole engine map with the help of a real-time capable approach. Afterwards an up to date turbulence model is introduced, which is based on a quasi-dimensional k " approach and can cope with turbulence production from large scale shearing. A simplified model for ignition delay is implemented which emphasizes the transfer from laminar to turbulent flame propagation after ignition. The modeling is completed with the calculation of overall heat release rates in a 0D entrainment approach with the help of turbulent flame velocities.
After validation of all sub-models, the 0D combustion prediction is used in combination with a 1D gas exchange analysis to virtually calibrate the modern engine torque structure and the ECU function for exhaust gas temperature with extensive simulations.