Patent ID: 6918361
Filing Date: 2005-07-19
Classification: F01L

Abstract:
1. A device for controlling at least one opening cross section in a combustion cylinder of an internal combustion engine, comprising: a gas exchange valve positioned in the combustion cylinder and having a displaceable valve element with a valve shaft and a valve closure member formed on the valve shaft, the valve closure member cooperating with a valve seat surrounding the opening cross section; an actuator that drives the valve element to execute an opening stroke that lifts the valve closure member up from the valve seat and a closing stroke that sets down the valve closure member on the valve seat; a valve brake operative during a closing stroke of the valve element, the valve brake having a hydraulic damping element producing a fluid displacement volume that flows out through a throttle cross section of a throttle opening; and a control unit for controlling the throttle cross section as a function of a viscosity of the fluid displacement volume; wherein the damping element has a damping cylinder, a damping piston fixedly connected to the lifting movement of the valve element and axially displaceable in the damping cylinder, and a volume displacement chamber fillable with a fluid, the volume displacement chamber being delimited by the damping piston and being connected to the throttle opening; wherein the damping element is integrated into the actuator; and wherein: the actuator has a double-acting working cylinder with a cylinder housing and an actuator piston displaceable within the cylinder housing, the actuator being fixedly connected to the valve shaft of the valve element and delimiting first and second pressure chambers in the cylinder housing, the first pressure chamber being acted upon by a fluid pressure, and the second pressure chamber having an inlet and a return, being acted upon by and relieved of the fluid pressure; the damping cylinder is one piece with the cylinder housing; the volume displacement chamber is in a fluid exchange connection with the second pressure chamber; and the damping piston is fixedly connected to the actuating piston in such a way that the damping piston seals the return after a predetermined closing stroke of the valve element.