Development costs and turnaround times can be significantly reduced by using a combination of computational and experimental methods. That is why, simulation methods have become an indispensable tool in the Diesel engines development process. The hardest part in this process is the model conception. The authors had created the model using a specialized soft "SolidEdge", the analysis being developed using Finite Element Method due to the COSMOS/M soft. In addition to the F.E.M., simulation methods are increasing in significance. Numerical methods are also becoming increasingly important as a tool for the development of combustion system applications. These methods provide a better understanding of the processes occurring inside an engine, allowing to perform dedicated fine- tuning of the various processes and to investigate the impact this has on performance, efficiency and emissions.