Field of the Invention
The invention relates to a device for setting the movement behavior of gas-exchange valves of an internal combustion engine having a camshaft. A control unit generates a setting signal which controls an adjustment of the camshaft. A pilot control system is additionally provided for additively correcting the setting signal.
An appliance for rotating a camshaft relative to the crankshaft in an internal combustion engine is known from German Patent DE 43 40 614 C2. The appliance has a control unit that generates a setting signal as a function of the deviation of an actual position of the camshaft from a required position. The setting signal is multiplicatively corrected by a correction factor that is determined as a function of a rotational speed and an oil temperature. Such appliances exhibit significant delay times, which reduce the maximum achievable control rate. It has been found, in practice, that the control unit can be parametrically organized either in such a way that a step in the required position is followed up only slowly or in such a way that there is a rapid follow-up to a step in the required position with the consequence of a small stability reserve. A rapid follow-up of steps in the required position is, however, necessary in order to also ensure comfortable operation of the internal combustion engine in transient operation with, at the same time, a low fuel consumption and high power.