A systematic control of mixture formation with modern high-pressure injection systems enables us to achieve considerable improvements of the combustion pr- ess in terms of reduced fuel consumption and engine-out raw emissions. However, because of the growing number of free parameters due to more flexible injection systems, variable valve trains, the application of different combustion concepts within different regions of the engine map, etc., the prediction of spray and m- ture formation becomes increasingly complex. For this reason, the optimization of the in-cylinder processes using 3D computational fluid dynamics (CFD) becomes increasingly important. In these CFD codes, the detailed modeling of spray and mixture formation is a prerequisite for the correct calculation of the subsequent processes like ignition, combustion and formation of emissions. Although such simulation tools can be viewed as standard tools today, the predictive quality of the sub-models is c- stantly enhanced by a more accurate and detailed modeling of the relevant pr- esses, and by the inclusion of new important mechanisms and effects that come along with the development of new injection systems and have not been cons- ered so far. In this book the most widely used mathematical models for the simulation of spray and mixture formation in 3D CFD calculations are described and discussed. In order to give the reader an introduction into the complex processes, the book starts with a description of the fundamental mechanisms and categories of fuel - jection, spray break-up, and mixture formation in internal combustion engines.

Combustion Engines Development nowadays is based on simulation, not only of the transient reaction of vehicles or of the complete driveshaft, but also of the highly unsteady processes in the carburation process and the combustion chamber of an engine. Different physical and chemical approaches are described to show the potentials and limits of the models used for simulation.

In the engine development process, simulation and predictive programs have continuously gained in reliance. Due to the complexity of future internal combustion engines the application of simulation programs towards a reliable “virtual engine development” is a need that represents one of the greatest challenges. Marco Chiodi presents an innovative 3D-CFD-tool, exclusively dedicated and optimized for the simulation of internal combustion engines. Thanks to improved or newly developed 3D-CFD-models for the description of engine processes, this tool ensures an efficient and reliable calculation also by using coarse 3D-CFD-meshes. Based on this approach the CPU-time can be reduced up to a factor 100 in comparison to traditional 3D-CFD-simulations. In addition an integrated and automatic “evaluation tool” establishes a comprehensive analysis of the relevant engine parameters. Due to the capability of a reliable “virtual development” of full-engines, this fast response 3D-CFD-tool makes a major contribution to the engine development process. Südwestmetall-Förderpreis 2010