Patent ID: 6729279
Filing Date: 2004-05-04
Classification: F01L

Abstract:
An arrangement for controlling an engine valve of a combustion engine comprising:the engine valve being movable between a valve closed and a valve opened condition; a piston connected with the engine valve for moving the engine valve between the valve closed and the valve opened conditions; a cylinder through which the piston is movable and the piston dividing the cylinder into first and second chambers defined at opposite sides of the piston; a loop hydraulic circuit; a pump in the hydraulic circuit which operates for pumping a hydraulic medium in a continuous flow through the hydraulic circuit in one direction; a control valve in the hydraulic circuit, the control valve being operable between a control valve first position and a control valve second position; in the control valve first position, a first fluid medium flow current is opened past the control valve to the first chamber for delivering the hydraulic medium to the first chamber and a second fluid medium flow current of the hydraulic medium is opened from the second chamber past the control valve for permitting exit of the hydraulic medium from the second chamber, whereby flow of the hydraulic medium into the first chamber moves the piston to move the engine valve to the open condition; the pump having an inlet disposed for receiving hydraulic medium which exits from the second chamber and in the control valve second position, a third fluid medium flow current of the hydraulic medium is opened past the control valve to the second chamber for delivering hydraulic medium to the second chamber and a fourth fluid medium current of the hydraulic medium is opened from the first chamber past the control valve for permitting exit of the hydraulic medium from the first chamber, whereby flow of the hydraulic medium into the second chamber moves the piston to move the engine valve to the closed condition; the pump inlet being disposed for receiving hydraulic medium which exits from the first chamber; whereby operation of the control valve between the control valve first and second positions respectively directs the continuous flow of medium into the first chamber and into the second chamber in the control valve first and second positions, respectively.