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Due to stricter fuel consumption and emissions requirements new gasoline engine concepts using advanced combustion systems such as fully variable valve train and controlled auto-ignition (HCCI) become important. Classical generic methods developed for system optimization with an increased number of variabilities (e.g. DoE - Design of Experiments), need extensions, because closed loop control is required for critical system parameters like valve train actuation and combustion behavior. This paper describes a new approach called “controlled optimization”, which is an extension of DoE using real-time controllers for critical system parameters (e. g. combustion timing). This ensures stable engine operation and protection under all conditions. Less critical parameters are still used as simple DoE-set values. Combustion timing, directly related to spark advance in conventional gasoline engines, is also strongly influenced by valve timing parameters.

To meet the future demands on internal combustion engines regarding efficiency emissions and durability all design parameters must be optimized together. As a result of progress in material engineering fuel injection technology turbo charging technology exhaust gas after treatment there arise a multiplicity of possible parameters, such as: design parameters (compression ratio, dimensioning depending on peak firing pressure and mean effective pressure), injection system (rate shaping, split injection, injection pressure, hole diameter), air management (turbo charging with or without VTG, EGR rate) combustion optimization (timing, air access ratio). The interaction of all these parameters can not be over-looked without simulation and optimization tools. This is valid for the concept layout, the optimization and the application process later on.