HYDRAULISCHES SYSTEM UNTER ELEKTRONISCHER KONTROLLE ZUR VARIABLEN BETÄTIGUNG DER VENTILE EINER BRENNKRAFTMASCHINE, MIT SCHNELLER BEFÜLLUNG DER HOCHDRUKTEILS DES SYSTEMS

A system (100) for variable actuation of the valves of an internal combustion engine having one or more cylinders, comprising, for each cylinder: - at least one intake valve and at least one exhaust valve (2), each provided with spring return means (3) adapted to return said valve (4) towards a closed position, - hydraulic means (4a, 5, C) including a pressurized fluid chamber (C), said pressurized fluid chamber (C) having a volume which is variable through the actuation of a pumping piston (6) facing the inside thereof, said pressurized fluid chamber (C) being hydraulically connected to an actuator (4) of said at least one intake valve or of said at least one exhaust valve, to enable the variable actuation thereof, - a tappet (7) actuated by a respective cam (8) carried by a camshaft (9) in order to control said pumping piston (6) and consequently said actuator (4) of said valve with variable actuation (2) by said hydraulic means (4a, 5, C), - a solenoid valve (11) hydraulically connected to said pressurized fluid chamber (C) and to said actuator, said solenoid valve (11) being adapted to set a hydraulic connection of said pressurized fluid chamber (C) and of said actuator (4) with an exhaust environment, in order to uncouple said valve with variable actuation (2) from the respective tappet (7) and to cause the closing thereof by said spring return means (3), - a first tank (12) defining said exhaust environment, - a hydraulic supply line (14) of said tank (12) connected thereto, and provided with a first check valve (15) adapted to allow a fluid flow only towards said tank (12), - a hydraulic accumulator (16) hydraulically connected (16a) to said first tank (12). The system (100) comprises a second check valve (17) hydraulically connected between said first tank (12) and said pressurized fluid chamber (C), said second check valve (17) being adapted to allow a fluid flow only out of said first tank (12) only, towards said pressurized fluid chamber (C), said second check valve (17) and said solenoid valve (11) being hydraulically connected in parallel to each other, and being both adapted to allow the fluid supply from said first tank (12) to said pressurized fluid chamber (C).