Patent ID: 8020526

Claim:
Hydraulic unit for a cylinder head of an internal combustion engine with a hydraulic, variable valve train, comprising: at least one drive-side master unit, at least one driven-side slave unit activating a gas-exchange valve, at least one controllable hydraulic valve, at least one medium-pressure chamber, at least one high-pressure chamber that is arranged in a transmission sense between an associated one of the at least one drive-side master unit and an associated one of the at least one driven-side slave unit and that can be connected to an associated one of the at least one medium-pressure chamber via an associated one of the at least one hydraulic valve, and a hydraulic housing with a housing bottom part and a housing top part, wherein at least the at least one master unit, the at least one slave unit, the at least one high-pressure chamber, the at least one hydraulic valve, and the at least one medium-pressure chamber in connection with the hydraulic housing belong to the hydraulic unit that can be mounted on the cylinder head, and a low-pressure chamber used as a hydraulic medium reservoir is formed in a housing top part, the low-pressure chamber communicates with the at least one medium-pressure chamber merely via at least one choke opening, and the choke opening passes through a separating wall extending between the at least one low-pressure chamber and the at least one medium-pressure chamber.