Abstract: An internal-combustion engine includes a three-way, three-position control valve with an inlet communicating with a pressurized-fluid chamber and with a hydraulic actuator of an intake valve, and two outlets communicating, respectively, with the actuator of the other intake valve and with said exhaust channel. The control valve has a first position, in which the inlet communicates with both of the outlets, a second position, in which the inlet communicates only with the outlet connected to the actuator of an intake valve and does not communicate, with the outlet connected to the exhaust channel, and a third position, in which the inlet does not communicate with the two outlets. The control valve has an electric actuator supplied only at three different values of electric current to bring the valve into the three positions.

Abstract: A fuel-injection system for an internal-combustion engine has at least one fuel injector with a fuel-metering servo valve provided with an open/close element, which is movable in response to the action of an electric actuator; and an electronic control unit which issues to the electric actuator two electrical commands, one for carrying out a pilot injection and one for carrying out a main injection; the two electrical commands being separated by an electrical dwell time such that the main injection starts, without solution of continuity with the pilot injection, when an open/close needle for carrying out fuel injections into a cylinder of the internal-combustion engine remains at a lift value in which the fuel flow rate is negligible; in particular, the second electrical command is issued during a rebound of the open/close element on the valve seat.

Abstract: A fuel electro-injector for a fuel injection system for an internal combustion engine, having an atomizer equipped with a nozzle and a valve needle defining a discharge section that is annular and has a width that continuously increases as the opening stroke of the valve needle proceeds. The opening stroke is directed outwards and is caused, in a proportional manner, by the operation of an electric actuator. The electro-injector has a high-pressure environment with an annular passageway around the lateral outer surface of the valve needle to supply fuel to the discharge section, and a low-pressure environment, which communicates with a fuel outlet and is separated from the high-pressure environment by a dynamic seal between the valve needle and the nozzle.

Abstract: An internal combustion engine for motor-vehicles, includes a system for variable actuation of the intake valves of the engine having a solenoid valve controllable between a closed condition and an open condition wherein it places a pressurized fluid chamber in communication with an exhaust chamber, with the aim of decoupling the intake valve from the respective tappet and causing the quick closing of the intake valve due to the respective return spring. The solenoid valve has a valve element with a cylindrical body having a first conical surface portion and a second conical surface portion. The conical surface portions are defined by the axially opposite ends of a circumferential groove formed on the valve element. The first conical surface portion cooperates with the valve seat. The other conical surface portion has an outer diameter substantially identical to the diameter of the annular edge defining the valve seat.

Abstract: An electrically actuated valve includes a first working way and a second working way and a poppet configured for providing a seal on a valve seat set hydraulically between the first working way and the second working way. The poppet includes a first operating position, a second operating position, and a third operating position, and is displaceable by an electrical-actuation device. In the first operating position, a passage area for a hydraulic fluid defined between said valve seat and said poppet has a maximum value. In the second operating position, the passage area is partialized and has a value lower than said maximum value. In the third operating position, the poppet is in contact with the valve seat, and the passage area has a substantially zero value, so that the first working way is isolated from the second working way.

Abstract: An internal-combustion engine includes a system for variable actuation of intake valves, including a control valve for each cylinder, which controls communication of a pressurized-fluid chamber with a discharge channel. The control valve has at least three different positions, namely, a first completely open position, a second partially open position, and a third completely closed position. Electronic control means are programmed for keeping the control valve in its closed position in operating stages in which the intake valve must remain coupled to the respective cam and for bringing the control valve from its completely closed position to its partially open position or to its completely open position in operating stages in which the intake valve must be uncoupled from the respective cam, selection between the first position and said second position of the control valve being made as a function of one or more operating parameters of the engine.

Abstract: An electrically actuated control valve has three mouths and three operating positions, in which the three mouths includes a first mouth for inlet of a working fluid, and a second mouth and a third mouth for outlet of the working fluid. The three operating positions include a first operating position in which a passage of fluid from the first mouth to the second mouth and the third mouth is enabled, a second operating position in which a passage of fluid from the first mouth to only one of said second and third mouths is enabled, and a third operating position in which the passage of fluid from the first to the second mouth and the third mouth is disabled. The control valve includes an electric or electromagnetic actuator for controlling the passage of fluid from the first mouth to the second and third mouths providing the aforesaid three operating positions.

Abstract: An internal-combustion engine includes a three-way, three-position control valve with an inlet communicating with a pressurized-fluid chamber and with a hydraulic actuator of an intake valve, and two outlets communicating, respectively, with the actuator of the other intake valve and with said exhaust channel. The control valve has a first position, in which the inlet communicates with both of the outlets, a second position, in which the inlet communicates only with the outlet connected to the actuator of an intake valve and does not communicate, with the outlet connected to the exhaust channel, and a third position, in which the inlet does not communicate with the two outlets. The control valve has an electric actuator supplied, only at three different values of electric current to bring the valve into the three positions.

Abstract: An internal-combustion engine includes a three-way, three-position solenoid valve, having an inlet communicating with a pressurized-fluid chamber and with a hydraulic actuator of an intake valve, and two outlets communicating with an actuator of another intake valve of a cylinder and the exhaust channel. The solenoid valve has a first position, in which the inlet communicates with both outlets, a second position, in which the inlet communicates only with the outlet connected to the actuator of the intake valve and a third position, in which the inlet does not communicate with any of the two outlets. During at least part of an active stroke of a tappet, the solenoid valve is kept in the third position to render the first intake valve active. During the active stroke of the tappet, the solenoid valve is never brought into the second position so that the second intake valve always remains closed.

Abstract: A solenoid valve comprises a first mouth for an inlet of a working fluid and a second mouth and a third mouth for an outlet of the working fluid. The valve has a first operating position in which a passage of fluid from the first mouth to the second mouth and the third mouth is enabled, a second operating position in which a passage of fluid from the first mouth to only one of the second and third mouths is enabled, and a third operating position in which the passage of fluid from the first to the second mouth and the third mouth is disabled.

Abstract: An internal-combustion engine with two intake valves 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 of the system with an exhaust channel. The solenoid valve is a three-way, three-position solenoid valve, comprising an inlet permanently communicating with the pressurized-fluid chamber and with the hydraulic actuator of an intake valve, and two outlets communicating, respectively, with the actuator of the other intake valve and with said exhaust channel. The solenoid valve has a first position, in which the inlet communicates with both of the outlets, a second position, in which the inlet communicates only with the aforesaid outlet connected to the actuator of an intake valve and does not communicate, instead, with the outlet connected to the exhaust channel, and a third position, in which the inlet does not communicate with any of the two outlets.

Abstract: A fuel injection system for an internal combustion engine, comprising: at least one fuel electroinjector; and one electronic control unit designed to supply the fuel electroinjector, in a fuel injection phase in an engine cylinder, with at least a first electrical command to perform a pilot fuel injection, and a second electrical command to perform a main fuel injection. The first and second electrical commands are separated in time by an electrical dwell time such that the main fuel injection starts without interruption with respect to the pilot fuel injection. The electrical dwell time between the first and second electrical commands belongs to an electrical dwell time range in which the total fuel amount injected in the pilot and main fuel injections in a fuel injection phase in an engine cylinder is substantially constant.

Abstract: A fuel injector has an injector body and a control rod, which is movable in the injector body along an axis to control the opening/closing of a nozzle that injects fuel into a cylinder of the engine; the injector body houses a metering servovalve having a control chamber, which is axially delimited by the control rod and communicates with an inlet and with a discharge channel; the metering servovalve is provided with a shutter, which slides axially on an axial guide, from which the discharge channel exits, to open and close the discharge channel and, in consequence, vary the pressure in the control chamber; the discharge channel has three restrictions having calibrated passage sections and arranged in series with each other to divide the pressure drop along the discharge channel.

Abstract: A fuel injector has an injector body and a control rod, which is movable in the injector body along an axis for controlling opening/closing of a nozzle that injects fuel in an engine cylinder; the injector body houses a metering servovalve, provided with a control chamber and with an open/close element of a balanced type, axial sliding of which causes a variation in pressure in the control chamber; the metering servovalve comprises a valve body made of two pieces coaxially coupled to one another via a deformable ring, which defines also a gasket for guaranteeing fluid tightness between the two pieces and maintains in a fixed position a disk on which a calibrated restriction is made.

Abstract: A fuel-injection system for an internal-combustion engine has at least one fuel injector with a fuel-metering servo valve provided with an open/close element, which is movable in response to the action of an electric actuator; and an electronic control unit which issues to the electric actuator two electrical commands, one for carrying out a pilot injection and one for carrying out a main injection; the two electrical commands being separated by an electrical dwell time such that the main injection starts, without solution of continuity with the pilot injection, when an open/close needle for carrying out fuel injections into a cylinder of the internal-combustion engine remains at a lift value in which the fuel flow rate is negligible; in particular, the second electrical command is issued during a rebound of the open/close element on the valve seat.

Abstract: A fuel injector has an injector body and a control rod, which is movable in the injector body along an axis to control the opening/closing of a nozzle that injects fuel into a cylinder of the engine; the injector body houses a metering servovalve having a control chamber, which is axially delimited by the control rod and communicates with an inlet and with a discharge channel; the metering servovalve is provided with a shutter, which slides axially on an axial guide, from which the discharge channel exits, to open and close the discharge channel and, in consequence, vary the pressure in the control chamber; the discharge channel has at least two restrictions having calibrated passage sections and arranged in series with each other to divide the pressure drop along the discharge channel.

Abstract: A solenoid valve comprises a first mouth for an inlet of a working fluid and a second mouth and a third mouth for an outlet of the working fluid. The valve has a first operating position in which a passage of fluid from the first mouth to the second mouth and the third mouth is enabled, a second operating position in which a passage of fluid from the first mouth to only one of the second and third mouths is enabled, and a third operating position in which the passage of fluid from the first to the second mouth and the third mouth is disabled.

Abstract: An internal-combustion engine with two intake valves 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 of the system with an exhaust channel. The solenoid valve is a three-way, three-position solenoid valve, comprising an inlet permanently communicating with the pressurized-fluid chamber and with the hydraulic actuator of an intake valve, and two outlets communicating, respectively, with the actuator of the other intake valve and with said exhaust channel. The solenoid valve has a first position, in which the inlet communicates with both of the outlets, a second position, in which the inlet communicates only with the aforesaid outlet connected to the actuator of an intake valve and does not communicate, instead, with the outlet connected to the exhaust channel, and a third position, in which the inlet does not communicate with any of the two outlets.

Abstract: An internal combustion engine for motor-vehicles, includes a system for variable actuation of the intake valves of the engine having a solenoid valve controllable between a closed condition and an open condition wherein it places a pressurized fluid chamber in communication with an exhaust chamber, with the aim of decoupling the intake valve from the respective tappet and causing the quick closing of the intake valve due to the respective return spring. The solenoid valve has a valve element with a cylindrical body having a first conical surface portion and a second conical surface portion. The conical surface portions are defined by the axially opposite ends of a circumferential groove formed on the valve element. The first conical surface portion cooperates with the valve seat. The other conical surface portion has an outer diameter substantially identical to the diameter of the annular edge defining the valve seat.

Abstract: A fuel injection system for an internal combustion engine, comprising: at least one fuel electroinjector; and one electronic control unit designed to supply the fuel electroinjector, in a fuel injection phase in an engine cylinder, with at least a first electrical command to perform a pilot fuel injection, and a second electrical command to perform a main fuel injection. The first and second electrical commands are separated in time by an electrical dwell time such that the main fuel injection starts without interruption with respect to the pilot fuel injection. The electrical dwell time between the first and second electrical commands belongs to an electrical dwell time range in which the total fuel amount injected in the pilot and main fuel injections in a fuel injection phase in an engine cylinder is substantially constant.