Patent ID: 7827951

Claim:
A gas exchange valve operating apparatus for an internal combustion engine with at least one overhead camshaft ( 10 , 10 ′) and with gas exchange valves ( 25 ) operated by the overhead camshaft ( 10 , 10 ′), with at least one hydraulic switchable support unit ( 13 ) and a lever-like cam follower ( 12 ) disposed on the support unit ( 13 ) and the valve ( 25 ) so as to be operated by the camshaft ( 10 , 10 ′) via the cam follower ( 12 ), each camshaft ( 10 , 10 ′) including a pressure medium supply passage ( 14 , 14 ′) and communication means extending between the camshaft ( 10 , 10 ′) and the support unit ( 13 ) placing it in communication with at least one pressure medium supply ( 16 ) via the pressure medium supply passage ( 14 , 14 ′) for supplying lubricant to the gas exchange valves ( 25 ), and a switching circuit ( 17 ) including a pressure control valve ( 41 ) for the pressure medium formed in the switching circuit of the support unit ( 13 ), which is in communication with a pressure medium supply ( 16 ) via the camshaft pressure medium supply passage ( 14 , 14 ′), and locking means ( 46 , 48 , 46 ′, 48 ′) for controlling the deactivation and reactivation of the valves depending on the pressure of the pressure medium in the switching circuit ( 17 ).