Apparatus and method for coupling and decoupling actuating elements of a valve drive of an internal combustion engine

Abstract

In a method and apparatus for coupling or decoupling two actuating elements of a valve drive of an internal combustion engine for operating a gas exchange valve, comprising a locking element movable between two end positions for coupling the actuating elements, an electromagnet for actuating the movable locking element, a permanent magnet is associated with the armature for holding the armature and the locking element in one end position and means for biasing the armature and the locking element in the opposite end position, the electromagnet is energizable in one sense for moving the armature into one end position in which the armature is retained by the permanent magnet with a force greater than a counteracting force generated by the biasing means, and in the opposite sense so as to generate a force exceeding that of the permanent magnet for moving the armature in the opposite end position, where it is retained by said biasing means.

1 . A method for coupling or decoupling two actuating elements ( 2 ,  3 ) of a valve drive of an internal combustion engine for operating a gas exchange valve ( 1 ), comprising a locking element ( 5 ) movable between two end positions for coupling the actuating elements ( 2 ,  3 ), an electromagnet ( 9 ) for actuating the movable locking element ( 5 ) and including a coil ( 9   a ) and a yoke ( 9   b ) interacting with an armature ( 10 ) which is operatively connected to the locking element ( 5 ), a permanent magnet ( 15 ) associated with the armature ( 10 ) for holding the armature ( 10 ) and the locking element ( 5 ) in one end position and means ( 11 ) for biasing the armature ( 10 ) and the locking element in the opposite end position, said method comprising the steps of: energizing the coil ( 9   a ) in one sense for moving the armature into one end position in which the armature is retained by said permanent magnet with a force greater than a counteracting force generated by the biasing means ( 11 ), and energizing the coil ( 9   a ) in the opposite sense for generating a force exceeding that of the permanent magnet ( 15 ) for moving the armature ( 10 ) in the opposite end position, where it is retained by said biasing means ( 11 ).  
     
     
         2 . A method as claimed in  claim 1 , wherein, after the energization by the permanent magnetic effect has been switched off, the armature ( 10 ) retains at least one of its positions assumed as a result of preceding energization of the electro-magnet ( 9 ).  
     
     
         3 . A method as claimed in  claim 1 , wherein the armature comprises a permanently magneticeable material and the armature is permanently magnetized in one sense by energization of the electromagnet ( 9 ).  
     
     
         4 . An apparatus for coupling or decoupling two actuating elements ( 2 ,  3 ) of a valve drive of an internal combustion engine for optionally operating a gas exchange valve ( 1 ), comprising a locking element ( 5 ) movable two end positions for coupling the actuating elements ( 2 ,  3 ), an electromagnet ( 9 ) for actuating the movable locking element ( 5 ) and including a coil ( 9   a ) and a yoke ( 9   b ) interacting with an armature ( 10 ) which is part of the locking element ( 5 ), a permanent magnet ( 15 ) associated with the armature ( 10 ) for holding the armature ( 10 ) and the locking element ( 5 ) in one end position and means ( 11 ) for biasing the armature ( 10 ) and the locking element in the opposite end position, said coil ( 9   a ) when energized in one sense moving the armature into one end position in which the armature is retained by said permanent magnet ( 15 ) with a force greater than a counteracting force generated by the biasing means ( 11 ), and the coil ( 9   a ) when energized in the opposite sense generating a force exceeding that of the permanent magnet for moving the armature in the opposite end position, where it is retained by said biasing means ( 11 ).  
     
     
         5 . The apparatus as claimed in  claim 4 , wherein the means ( 11 ) for biasing the armature ( 10 ) in the opposite end position is a spring element ( 11 ).  
     
     
         6 . The apparatus as claimed in  claim 4 , wherein, the permanent magnetic force is generated by a permanent magnetic device ( 15 ) attached to the armature ( 10 ).  
     
     
         7 . The apparatus as claimed in  claim 4 , wherein the permanent magnetic force is generated by the armature ( 10 ) being permanently magnetized.  
     
     
         8 . The apparatus as claimed in  claim 4 , wherein the actuating elements comprise one of a camshaft adjuster, a supporting element, an equalizing element, a cam follower and a camshaft.