Weber, J: Optimization Methods for the Mixture Formation and

obtained. If the same spray parameters are applied to a virtual engine case, a similar good agreement is achieved although the mesh resolution is much finer and the mesh topology is different than for the spray chamber simulation. From this result, spray data for engine simulations should be provided and be used for sake of calibration before the engine simulation is conducted. Additionally data is obtained by PDA measurements at discrete points in the spray. That measurement technique is, however, limited to less dense areas. Nevertheless, it shows that also local data is in agreement with the simulation data. Agreement with spray penetration is thus a relatively good choice and accounts also for the physics on a local or microscopic level. That hypothesis is well supported by the data from the ethanol spray calibration. The excellent agreement with regard to the global spray penetration is reflected by the 2D comparison of liquid and vapor fuel concentrations and temperature, respectively. Furthermore, a similar good agreement in spray penetration is obtained if the breakup and collision model is not used. In that case, the spray penetration is only controlled by the evaporation process. The Genetic Algorithm finds a point in the parameter space with an initial SMR that is of the order of size of the outcome of the secondary droplet breakup. However in engine simulations, spray data is not always available. In that case the spray parameters have to be adjusted. That adjustment is carried out following a methodology that is presented in this work. Mainly, SOI and EGR variations have to be used to calibrated the spray and combustion model. That approach has been investigated for three different engine data sets for conventional and PCCI combustion mode. On the Cummins QSX engine, a conventional combustion has been studied. Spray parameters are subject of adjustment. On the Duramax 6600 Diesel engine, a conventional and PCCI combustion mode are investigated. For the PCCI combustion mode, the reaction mechanism is modified in order to account for a correct ignition delay in the low temperature combustion regime. The comparison between engine data and results from the simulation indicates a good agreement for the combustion and engineout emissions. On the Duramax full load case, most uncertainties are addressed to the spray-wall interaction. Uncertainties from physical not well based models will always occur in the engine simulation. Therefore, calibration of these models is a mean to quantify its influence and minimize the discrepancies.