Due to the large number of influencing parameters and interactions, the fuel injection and therewith fuel propagation and distribution are among the most complex processes in an internal combustion engine. For this reason, injection is usually the subject to highly detailed numerical modeling, which leads to unacceptably high computing times in the 3D-CFD simulation of a full engine domain. Marlene Wentsch presents a critical analysis, optimization and extension of injection modeling in an innovative, fast response 3D-CFD tool that is exclusively dedicated to the virtual development of internal combustion engines.