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 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.

Abstract: The injector comprises a balanced metering servovalve for controlling a rod for opening/closing a nebulizer. The servovalve has a valve body having a control chamber provided with an outlet passage that is opened/closed by an axially mobile open/close element. The open/close element is made of a single piece with a bushing separate from an armature plate of an electromagnet. The bushing is coupled to a stem in an axially slidable way for closing an exhaust duct in communication with the outlet passage The open/close element is kept in a closed position by a spring that acts upon the bushing through an intermediate body connected thereto. The armature plate can be displaced with respect to the bushing between a flange of the intermediate body and a shoulder of the bushing, for eliminating the rebounds of the open/close element upon closing of the servovalve.

Abstract: The injection system comprises a pump designed to send fuel at high pressure to an accumulation volume, for example formed by a common rail, for supplying a plurality of injectors. The pump comprises at least one pumping element actuated with reciprocating motion with a compression stroke at a sinusoidal speed, in synchronism with each step of fuel injection. The injection system comprises at least one by-pass solenoid valve, which is controlled by a chopper control unit for modulating the delivery of the pumping element by varying both the instant of start and the instant of end of delivery during the compression stroke, in such a way that the delivery is synchronous with the injection phase.

Abstract: The injector comprises a metering servo valve for controlling a rod for opening/closing a nebulizer. The servo valve has a valve body having a control chamber provided with an outlet passage that is opened/closed by an open/close element that is axially movable. The open/close element is separate from an armature of an electromagnet, and is slidable on an axial guide element for closing the outlet passage. The open/close element is held in the closing position by a spring acting through an intermediate body. The armature can be displaced with respect to the axial guide element between a flange of the intermediate body and a projection element of the guide member, for eliminating the rebounds of the open/close element upon closing of the solenoid valve.

Abstract: A metering servovalve for a fuel injector of an internal combustion engine has an electro-actuator and a fixed valve body, which defines a control chamber communicating with an inlet and with an outlet channel. The outlet channel has at least one calibrated restriction and exits through the lateral surface of an axial stem, on which a sleeve slides, in a substantially fluid-tight manner, to open/close the outlet channel and so vary the pressure in the control chamber. The outlet channel is closed by an end portion of the sleeve that is elastically deformable in a radially outward direction, under the thrust of the fuel pressure, to increase the diameter at which the seal against the valve body is formed, with respect to a non-deformed state, and to generate an axial unbalancing force on the sleeve upon opening when the outlet channel is closed.

Abstract: The injector comprises a balanced metering servovalve to control a rod for the opening/closing of a nozzle. La servovalve has a valve body with a control chamber radially delimited by a tubular portion and fitted with an outlet passage that is opened/closed by an axially movable shutter. The servovalve is also integral with an axial stem, provided with a lateral surface, through which the outlet channel exits. The shutter is coupled to the stem in an axially sliding manner and, when it closes the outlet passage, it is subjected to substantially null axial fuel pressure. The outlet passage has a calibrated segment distanced from the shutter and close to a bottom wall of the control chamber. The calibrated segment is carried by an element fixed to the valve body in correspondence to an axial segment of the outlet passage.

Abstract: The injection system (1) includes a storage volume (6) of pressurized fuel supplied by a high-pressure pump (7) along a delivery pipe (8); and a control unit (16) for defining the required fuel pressure of the storage volume (6) as a function of the operating conditions of the engine (2). The regulating device includes a bypass solenoid valve (14); and a pair of non-return valves (32, 33) connected antiparallel and located between the bypass valve (14) and the storage volume (6). One of the non-return valves (32, 33) permits fuel drainage from the storage volume (6) to the bypass valve (14) when the control unit (16) defines a predetermined reduction (?p) in the fuel pressure of the storage volume (6).

Abstract: A fuel injector comprising a hollow body for housing a metering valve with a calibrated pipe for outlet of the fuel from a control chamber. The calibrated pipe is normally kept closed by a shutter controlled by an electromagnet comprising a magnetic core and an electric coil housed in an annular slot of the core. The coil outer cylindrical surface forms a gap with the annular slot so as to be lapped by the fuel coming out of the calibrated pipe. The coil comprises a bobbin having a pair of appendages for supporting electric supply plugs, which are englobed at least in part in a block of non-magnetic material. The bobbin has a substantially cylindrical rib, one flange adjacent to an end portion of the plugs, and another flange having a smaller diameter that forms a passage for the fuel between the calibrated pipe and the gap.

Abstract: A servo valve (7) for fuel control is provided with an actuator (14) and a valve body (8, 28), which is set in a fixed position and has a stem (33) that extends along a longitudinal axis (3) and defines an internal passage (26); said internal passage (26) has at least two radial channels (39), which give out into an outlet through an outer lateral surface (34) of the stem (33) and have respective first portions (43) of calibrated length and cross section; said first portions (42) are followed by respective second portions of larger diameter; the servo valve (7) is provided with an open/close element (17), which is coupled to the outer lateral surface (34) of the stem (33) substantially in a fluid-tight way and is axially movable under the action of the actuator (14) for opening/closing the internal passage (26) of the stem (33); in the closing position, the open/close element (17) is subject to a zero axial resultant force by the pressure of the fuel.

Abstract: A fuel injector and servovalve for an internal combustion engine.

Abstract: The fuel injection system comprises a fuel injector controlled by commands of a control unit. The fuel injector comprises a metering servo valve having a control chamber provided with an outlet passage that is opened/closed by an open/close element that is axially movable. The open/close element is carried by an axial guide element that is separate from an armature of an electromagnet. The open/close element is held in the closing position by a spring acting through an intermediate body. In some instances, the strokes of the open/close element and of the armature are chosen so as to eliminate, upon closing of the servo valve, the rebounds of the open/close element subsequent to the first rebound. The control unit controls a fuel injection comprising a pilot fuel injection and a main fuel injection, via two distinct electrical commands, which are spaced apart by a dwell time such as to occur in an area of reduced variation of the amount of injected fuel.

Abstract: The system comprises an injector controlled by commands of a control unit. The injector comprises a dosing servo valve having a control chamber provided with an outlet passage that is opened/closed by an open/close element that is axially movable. The open/close element is carried by an axial guide element that is separate from an anchor of an electromagnet. The open/close element is held in the closing position by a spring acting through an intermediate body. Preferably, the strokes of the open/close element and of the anchor are chosen so as to eliminate, upon closing of the solenoid valve, the rebounds of the open/close element subsequent to the first rebound. The control unit controls an injection comprising a pre-injection and a main injection, via two distinct electrical commands, which are spaced apart by a dwell time such as to occur in an area of reduced variation of the amount of injected fuel; therefore, the stability of operation of the system increases as said dwell time varies.

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 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: The injector comprises a balanced metering servovalve for controlling a rod for opening/closing a nebulizer. The servovalve has a valve body having a control chamber provided with an outlet passage that is opened/closed by an axially mobile open/close element. The open/close element is made of a single piece with a bushing separate from an armature plate of an electromagnet. The bushing is coupled to a stem in an axially slidable way for closing an exhaust duct in communication with the outlet passage The open/close element is kept in a closed position by a spring that acts upon the bushing through an intermediate body connected thereto. The armature plate can be displaced with respect to the bushing between a flange of the intermediate body and a shoulder of the bushing, for eliminating the rebounds of the open/close element upon closing of the servovalve.

Abstract: The injector comprises a dosing servo valve for controlling a rod for opening/closing a nebulizer. The servo valve has a valve body having a control chamber provided with an outlet passage that is opened/closed by an open/close element that is axially movable. The open/close element is separate from an anchor of an electromagnet, and is slidable on an axial guide element for closing the outlet passage. The open/close element is held in the closing position by a spring acting through an intermediate body. The anchor can be displaced with respect to the axial guide element between a flange of the intermediate body and a projection element of the guide member, for eliminating the rebounds of the open/close element upon closing of the solenoid valve.

Abstract: A fuel adjustment and filtering device for a high-pressure pump of a fuel injection system, the device comprising at least one filter, comprising a removable filter cartridge, comprising a filtering body, housed within a filter casing; a shut-off solenoid valve for metering fuel; and, a pressure control valve for the fuel. The solenoid valve and pressure control valve are housed in a block separate from the pump. In one embodiment, in which the pressure control valve is optional, the solenoid valve may be mounted on the filter casing.