Abstract
Unthrottled SI engines with variable valve actuation are one of the most promising technologies that were proposed in the last years for the reduction of gasoline consumption, especially at part loads. With respect to conventional, throttled engines, they introduce a major control task, that consists in the valve motion regulation, in order to track all the driver's load requests. Various valve control strategies have been introduced for this purpose. The electrohydraulic actuation appears to be the one with less impact on the traditional engine configuration.
In this paper, the development of a valve actuation controller is presented. The control logic is based upon a predictive model of the charge induction process, that is able to estimate the mass inducted per cycle during the online running of the engine, and was validated with respect to experimental data from a 5-cylinders VVA engine.
The control architecture is described in the paper. A feedforward action has been derived by optimizing the actuation commands in order to maximize the engine efficiency. A feedback action is also included, and the performances of the proposed strategy in tracking the desiderated load are verified with various engine simulations.