Efficient Layout and Calibration of Variable Valve Trains

Today it is relatively common for modern SI engines to have dual continuously controlled camshaft phasing. To achieve less fuel consumption and emissions the optimal valve timing has to be chosen for every operating point. Conventional grid measurement leads to unacceptably long duration of measurement. This paper shows that statistical experimental methods - like Design of Experiments (DoE) - can shorten test expenses and development time by more than the factor of ten without quality loss. Different layout strategies are applied and compared using the same data set. Using this method the complex relationships of full variable valve trains can be treated, which was not possible until now.