Apparatus for adjusting a camshaft, and method for operating an apparatus for adjusting a camshaft

Abstract

In an apparatus for adjusting a phase position of a camshaft in relation to a crankshaft which drives the camshaft, including an electric actuator for operating an adjustment mechanism, which can move the camshaft to a basic or emergency-operating position in the event of a shut-down as a result of an operational fault, the emergency-operating position can be reliably reached with the aid of the electric actuator which is supplied with energy by an energy supply that is separate from an operational energy supply and which is capable of moving the adjustment mechanism to the emergency-operating position. Also, a method for operating an apparatus for adjusting a phase position of a camshaft is provided.

1 . An apparatus for adjusting a phase position of a camshaft ( 12 ) in relation to a crankshaft which drives the camshaft ( 12 ), said apparatus including an adjustment mechanism for adjusting the phase position of the camshaft relative to the camshaft, an actuator ( 15 ) for operating the adjustment mechanism ( 11 ), the camshaft ( 12 ) being movable to an emergency-operating position in the event of a shut-down as a result of an operational fault, and an energy supply ( 19 ,  22 ) separate from an operating energy supply provided for the actuator ( 15 ) for supplying energy thereto for moving the adjustment mechanism ( 11 ) to the emergency-operating position.  
     
     
         2 . The apparatus as claimed in  claim 1 , wherein the separate energy supply ( 19 ,  22 ) comprises an energy store ( 19 ), by which the actuator ( 15 ) can be supplied with energy for a brief period of time.  
     
     
         3 . The apparatus as claimed in  claim 1 , wherein the separate energy supply ( 19 ,  22 ) is activatable by an engine controller ( 23 ).  
     
     
         4 . The apparatus as claimed in  claim 1 , wherein the energy supply ( 19 ) comprises a storage battery.  
     
     
         5 . The apparatus as claimed in  claim 1 , wherein the energy supply ( 19 ) comprises a capacitor.  
     
     
         6 . The apparatus as claimed in  claim 1 , wherein the separate energy supply ( 19 ,  22 ) comprises a connection ( 22 ) to an on-board vehicle electrical system ( 16 ), which connection is independent of the operating supply.  
     
     
         7 . The apparatus as claimed in  claim 1 , wherein the adjustment mechanism ( 11 ) is designed such that it automatically moves to a first end stop position when the actuator ( 15 ) is in the de-energized state.  
     
     
         8 . The apparatus as claimed in  claim 1 , wherein the actuator ( 15 ) is in the form of an electric brake.  
     
     
         9 . The apparatus as claimed in  claim 1 , wherein the actuator ( 15 ) is in the form of a hysteresis brake.  
     
     
         10 . The apparatus as claimed in  claim 9 , wherein the hysteresis brake has a separate auxiliary coil ( 27 ) which is actuatable in the event of an operational fault in a field coil ( 26 ) of the hysteresis brake.  
     
     
         11 . A method for operating an apparatus for adjusting a phase position of a camshaft ( 12 ) in relation to a crankshaft which drives the camshaft ( 12 ), the apparatus including an electric actuator ( 15 ) for operating an adjustment mechanism ( 11 ), with the camshaft ( 12 ) being movable to an emergency-operating position in the event of a shut-down as a result of an operational fault, said method comprising the steps of supplying the actuator ( 15 ) with energy from an energy supply ( 19 ,  22 ) which is separate from its normal operating energy supply for moving the adjustment mechanism ( 11 ) to the emergency-operating position.  
     
     
         12 . The method as claimed in  claim 11 , wherein, in the de-energized state, the adjustment mechanism ( 11 ) automatically moves to a first end stop position.  
     
     
         13 . The method as claimed in  claim 11 , wherein the adjustment mechanism ( 11 ) is moved in the direction toward a second end stop position by the actuator ( 15 ) which can be supplied with power by the separate energy supply ( 19 ,  22 ), for reaching a locking position in which the adjustment mechanism ( 11 ) is then locked.  
     
     
         14 . The method as claimed in  claim 13 , wherein the adjustment mechanism ( 11 ) is firmly engaged in the locked position.