Electrohydraulic valve actuator with reciprocating cam

Electrohydraulic valve actuator with cylinder and reciprocating cam for internal combustion engine (100), characterized in that it comprises:

• at least one valve-actuating hydraulic cylinder (2) which comprises at least one valve-actuating piston (3) which opens at least one valve (101) of an internal combustion engine (100) or of a piston compressor when the cylinder (2) is connected by a valve-opening solenoid valve (4) to at least one incoming high-pressure hydraulic circuit (5), said cylinder (2) closing said valve (101) when it is connected by a valve-closing solenoid valve (6) to at least one outgoing high-pressure circuit (7), and said cylinder (2) maintaining said valve (101) open when it is connected neither to the incoming high-pressure circuit (5) nor to the outgoing high-pressure circuit (7);
• at least one hydraulic positive displacement pump (8) comprising at least one outlet connected to a low-pressure circuit (9) connected to at least one low-pressure reservoir (10) and at least one inlet connected to said low-pressure hydraulic circuit (9), said pump (8) rotating at a speed proportional to that of a crankshaft (102) of the internal combustion engine (100);
• at least one high-pressure valve-opening duct (11) connecting the output of the hydraulic positive displacement pump (8) to the incoming high-pressure hydraulic circuit (5) of the valve-actuating hydraulic cylinder (2);
• at least one valve-closing high-pressure duct (12) connecting the inlet of the hydraulic positive displacement pump (8) to the outgoing high-pressure hydraulic circuit (7) of the valve-actuating hydraulic cylinder (2);
• at least one pump outlet closure member (13) which is able to prevent the hydraulic fluid expelled at the outlet of the hydraulic positive displacement pump (8) from returning to the low-pressure hydraulic circuit (9), so that said fluid is forced into the high-pressure valve-opening duct (11);
• at least one pump inlet non-return valve (14) which prevents the hydraulic fluid coming from the valve-actuating hydraulic cylinder (2) via the high-pressure valve-closing duct (12) from returning directly to the low-pressure hydraulic circuit (9), so that said fluid is forced to the inlet of the hydraulic positive displacement pump (8) while said valve enables the pump to intake the fluid contained in the low-pressure hydraulic circuit (9) when the pressure of the latter is greater than the pressure in the valve-closing high-pressure duct (12);
• at least one valve-opening cam (15) connected on the one hand to the valve-actuating hydraulic cylinder (2) by a mechanical transmission (16) and on the other hand to the valve (101) of the internal combustion engine (100) either directly or through an intermediate transmission (17), said cam (15) moving in one direction during the opening operations of the valve (101), then in the opposite direction during the closing operations of the valve (101);
• at least one return spring (19) of the valve-opening cam (15) which tends to return the cam (15) into the position it is in when the valve (101) of the internal combustion engine (100) is closed.