This paper considers an overview of the fully variable valve train as a possible
solution to reduce emissions and improve internal combustion engines. For a complete understanding of the full variable valve train (FVVT) system that is described in this chapter it is important to understand the basics of a conventional valve train as currently used in common four-stroke combustion engines. First, the BMW K71 engine that is being used for this research project will be presented. To demonstrate the reasons for substituting the conventional valve train by a mechatronic control unit, the basics of a four-stroke engine and its valve actuation are explained in detail. Furthermore, the influence of the engine valve control with regard to performance and emissions is explained. The chapter closes with research results on existing (fully) variable valve trains.