Multicylinder internal -combustion engine with electronically controlled hydraulic device for controlling variable actuation of the valves, integrated in a pre-assembled unit mounted on the engine cylinder head

A multicylinder internal-combustion engine, comprising:

• at least one intake valve and at least one exhaust valve for each cylinder, each valve being provided with respective elastic return means, which push the valve towards a closed position for controlling respective intake and exhaust pipes;
• and
• at least one camshaft, for activating the intake valves and exhaust valves of the engine cylinders by means of respective tappets;
• in which each intake valve is controlled by the respective tappet against the action of the aforesaid elastic return means by interposition of hydraulic means that include a pressurized fluid chamber;
• said pressurized fluid chamber being designed to be connected by means of a solenoid valve to an exhaust channel in order to uncouple the valve from the respective tappet and bring about fast closing of the valve as a result of the respective elastic return means;
• electronic control means for controlling each solenoid valve so as to vary the time and the opening stroke of the respective intake valve according to one or more operating parameters of the engine;
• in which the hydraulic control means for controlling the intake valves of the engine and the solenoid valves associated thereto form part of a pre-assembled unit mounted on the engine cylinder head.
• wherein associated the aforesaid pre-assembled unit integrates also the supports on which the camshaft is mounted so that it can turn.