Patent ID: 6997147

Claim:
An electrohydraulic unit for actuating the valves of an endothermic engine comprising a hydraulic actuator for lifting a respective valve by means of a pressurized liquid and a spring antagonistic to the hydraulic actuator in order to close the valve and to discharge the liquid from the hydraulic actuator in the final closure phase of the valve; the unit being characterized in that it comprises a calibrated orifice through which to pass said liquid in order to slow down the expulsion of the liquid and to maintain a substantially constant closing velocity of the valve during discharge of the liquid from the hydraulic actuator; characterized in that it comprises regulation means for varying the open cross-section of said calibrated orifice in such a manner as to regulate the closing velocity of the valve; said calibrated orifice having an open cross-section that can be varied between a minimum value and a maximum value; said regulation means being capable of varying said open cross-section by means of a plurality of oscillation cycles between said maximum value and said minimum value; each oscillation cycle having a corresponding average value of the open cross-section.