Apparatus for variably adjusting the control times of gas exchange valves in an internal combustion engine

Abstract

An apparatus for variably adjusting control times of gas exchange valves in an internal combustion engine. The apparatus has a driving element, an output element, at least one pressure chamber, a pressurized medium supply device, and at least one pressure accumulator. The supply device allows pressurized medium to be fed to or discharged from the pressure chamber. A phase angle of the output element relative to the input element can be changed by feeding or discharging pressurized medium to or from the pressure chamber. The pressure accumulator encompasses a movable element that has a first pressure surface which partially delimits a storage space. The storage space is or can be connected to the supply device. An energy store applies a force to the movable element in the direction of an initial position. The movable element can be moved against the force of the energy store by pressurizing the storage space.

1 . A device for variably adjusting control times of gas exchange valves of an internal combustion engine, comprising:
 a drive input element; a drive output element; at least one pressure chamber; a pressure medium supply device; and at least one pressure accumulator,   with it being possible for pressure medium to be supplied to or discharged from the at least one pressure chamber by means of the pressure medium supply device,   with it being possible for a phase position of the drive output element relative to the drive input element to be varied by means of the supply of pressure medium to or discharge of pressure medium out of the pressure chamber,   with the pressure accumulator having a movable element which is provided with a first pressure surface which partially delimits a store chamber,   with the store chamber being connected or being connectable to the pressure medium supply device,   with a force store loading the movable element with a force in a direction of an initial position, and   with it being possible by means of a pressurization of the store chamber for the movable element to be moved counter to the force of the force store,   wherein the movable element has a counterpressure surface which at least partially delimits a counterpressure chamber, with it being possible by means of the pressurization of the counterpressure chamber for the movable element to be moved in the direction of the initial position.   
     
     
         2 . The device of  claim 1 , wherein the movable element has at least one second pressure surface which partially delimits a control chamber, with it being possible by means of an application of pressure medium to the control chamber for the movable element to be moved counter to the force of the force store, and with a pressure medium flow within the pressure accumulator from the store chamber into the control chamber being prevented. 
     
     
         3 . The device as  claim 2 , wherein an application of pressure medium to the store chamber moves the movable element in the same direction as an application of pressure medium to the control chamber. 
     
     
         4 . The device of  claim 1 , wherein the counterpresssure chamber can be selectively connected to a pressure source or to a tank. 
     
     
         5 . The device of  claim 1 , wherein control means are provided, with it being possible for the counterpressure chamber to be selectively connected to a tank or to a pressure source by the control means. 
     
     
         6 . The device of  claim 1 , wherein the counterpressure chamber can be connected to a pressure medium pump of the internal combustion engine. 
     
     
         7 . The device of  claim 1 , wherein the counterpressure chamber can be connected to a tank of the internal combustion engine. 
     
     
         8 . The device of  claim 5 , wherein a directional valve is provided as a control means, which directional valve has in each case one port connected to a pressure source, to a tank and to the counterpressure chamber. 
     
     
         9 . The device of  claim 8 , wherein the directional valve has a further port which is connected to the store chamber or to a control chamber. 
     
     
         10 . The device of  claim 2 , wherein the store chamber and the control chamber do not communicate with one another within the pressure accumulator.