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

Abstract

An apparatus for variably adjusting the 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 pressurized medium supply device allows pressurized medium to be fed to or discharged from the at least one pressure chamber. A phase angle of the output element relative to the driving element can be changed by supplying 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 connected to the pressurized medium supply device. The movable element can be moved against the force of an 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 to the pressure medium supply device,   with it being possible by means of the pressurization of the store chamber for the movable element to be moved counter to the force of a force   wherein the movable element has at least one second pressure surface which partially delimits a control chamber,   with it being possible by means of the pressurization of 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,   
     
     
         2 . The device of  claim 1 , wherein, during operation of the internal combustion engine, the control chamber is selectively connectable to a pressure source or to a tank. 
     
     
         3 . The device of  claim 1 , wherein the control chamber can be emptied into a tank without diversion via a consumer. 
     
     
         4 . The device of  claim 2 , wherein control means are provided, with it being possible for the control chamber to be selectively connected to a tank or to the pressure source by the control means. 
     
     
         5 . The device of  claim 2 , wherein control means are provided,
 which, in a first state, block a pressure medium flow from the store chamber to the pressure medium supply device and permit a pressure medium flow to the store chamber and to the control chamber, and   which, in a further state, permit the pressure medium flow from the store chamber to the pressure medium supply device and produce a connection between the control chamber and a tank without diversion via a consumer.   
     
     
         6 . The device of  claim 5 , wherein a store line is provided which connects the pressure medium supply device to the store chamber, and a control line is provided which connects the control chamber to a pressure source. 
     
     
         7 . The device of  claim 6 , wherein the control means is designed as a single directional valve which has in each case one port for the store line, the control line, the control chamber, the store chamber and the tank. 
     
     
         8 . The device of  claim 6 , wherein the control means comprise at least one first directional valve which is arranged in the control line. 
     
     
         9 . The device of  claim 8 , wherein the control means also comprise a second directional valve or a double check valve which is arranged in the store line. 
     
     
         10 . The device of  claim 8 , wherein the control means also comprise a double check valve which is arranged in the store line. 
     
     
         11 . The device of  claim 5 , wherein the store chamber and the control chamber are connected via a check valve, with a connection being arranged between control means and the store chamber and the control chamber and with the check valve blocking a pressure medium flow from the store chamber to the control chamber. 
     
     
         12 . The device of  claim 1 , wherein a check valve is provided between the control chamber and the pressure source, which check valve blocks a pressure medium flow from the control chamber in a direction of the pressure source. 
     
     
         13 . The device of  claim 1 , wherein a check valve is provided between the store chamber and the pressure medium supply device, which check valve blocks a pressure medium flow from the pressure medium supply device in a direction of the store chamber. 
     
     
         14 . The device of  claim 1 , wherein a pressurization of the store chamber moves the movable element a same direction as a pressurization of the control chamber. 
     
     
         15 . The device of  claim 1 , wherein the movable element has a third pressure surface which at least partially delimits a counterpressure chamber, with a pressurization of the counterpressure chamber moving the movable element in a opposite direction to a pressurization of the control chamber or of the store chamber. 
     
     
         16 . The device of  claim 2 , wherein a ratio between the minimum throughflow cross-section between the control chamber and the tank and the minimum throughflow cross-section between the store chamber and an actuating unit is greater than a ratio between a surface area of the second pressure surface and a surface area of the first pressure surface. 
     
     
         17 . The device of  claim 1 , wherein the store chamber and the control chamber do not communicate with one another within the pressure accumulator. 
     
     
         18 . The device of  claim 4 , wherein the control means are designed as a directional valve.