Internal combustion engine having a system for variable actuation of the intake valves, provided with a three-way solenoid valve

摘要

An internal-combustion engine with two intake valves (7A, 7B) for each cylinder is provided with a system for variable actuation of the intake valves, comprising a single solenoid valve for each cylinder that controls communication of the pressurized-fluid chamber (C) of the system with an exhaust channel (23). The solenoid valve is a three-way, three-position solenoid valve, comprising an inlet (i) permanently communicating with the pressurized-fluid chamber and with the hydraulic actuator of an intake valve (7B), and two outlets (u1, u2) communicating, respectively, with the actuator of the other intake valve (7A) and with said exhaust channel. The solenoid valve has a first position (P1), in which the inlet communicates with both of the outlets, a second position (P2), in which the inlet communicates only with the aforesaid outlet (u1) connected to the actuator of an intake valve (7A) and does not communicate, instead, with the outlet (u2) connected to the exhaust channel (23), and a third position (P3), in which the inlet (i) does not communicate with any of the two outlets (u1, u2).