Patent ID: 7162982

Claim:
A hydraulic valve actuator for reciprocating engines, comprising: at least one hydraulic jack ( 3 ) connected to a high-pressure hydraulic circuit ( 10 ) by means of a duct and ensuring the opening of at least one valve ( 2 ), at least one hydraulic positive displacement pump ( 4 ) comprising at least one outlet and at least one inlet, and rotating at a speed proportional to that of the engine crankshaft, at least one pump outlet plug ( 8 ) which makes it possible to prevent the hydraulic fluid expelled at the outlet of the hydraulic positive displacement pump ( 4 ) from issuing into a low-pressure circuit ( 9 ) or into a reservoir ( 58 ) and to force it into a high-pressure circuit ( 10 ) communicating with one or more hydraulic jacks ( 3 ) ensuring the opening of one or more valves ( 2 ), at least one valve opening selector ( 11 ) which makes it possible to direct, via the high-pressure circuit ( 10 ), the hydraulic fluid expelled at the outlet of the hydraulic positive displacement pump ( 4 ) toward the hydraulic jack ( 3 ) of at least one valve ( 2 ) to be opened, while at the same time preventing said hydraulic fluid from being directed toward one or more other valves ( 2 ) to remain closed, at least one opening nonreturn valve ( 24 ) which is located on the high-pressure circuit ( 10 ) between the outlet or outlets of the hydraulic positive displacement pump ( 4 ) and the hydraulic jack ( 3 ) of at least one valve ( 2 ) and which makes it possible to retain the hydraulic fluid in said hydraulic jack ( 3 ) of said valve ( 2 ) in order to keep it open, at least one valve closing selector ( 25 ) which makes it possible to direct the hydraulic fluid contained in the hydraulic jack ( 3 ) of at least one valve ( 2 ) kept open by the opening nonreturn valve ( 24 ) toward the inlet or inlets of the hydraulic positive displacement pump ( 4 ), in order to ensure the closing of said valve or valves ( 2 ) and to prevent the hydraulic fluid contained in their hydraulic jacks ( 3 ) from being introduced into the hydraulic jack ( 3 ) of another valve or other valves ( 2 ) which is or are to remain in a closed position, and at least one pump inlet nonreturn valve ( 26 ) which is located at the inlet or inlets of the hydraulic positive displacement pump ( 4 ) and which makes it possible for the hydraulic fluid of the low-pressure circuit ( 9 ) or of the reservoir ( 58 ) to be admitted at the inlet or inlets of the hydraulic positive displacement pump ( 4 ) when the pressure of said low-pressure circuit ( 9 ) or of said reservoir ( 58 ) is higher than that of said inlet or inlets of the hydraulic positive displacement pump ( 4 ).