Abstract: The invention relates to an actuator (1) comprising a housing (8), a coil (29) and an armature (2) which interacts with a tappet (30) and a spring, the armature plate (3) thereof being arranged to lie opposite an armature counterpiece (16), and said actuator (1) comprising at least one magnetostrictively-active component. According to the invention, an actuator (1) is provided with which large actuating paths can be travelled at high actuating forces. This is achieved by the actuator (1) additionally being designed to act as a solenoid.

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: The invention relates to an actuator (1) comprising a housing (8), a coil (29) and an armature (2) which interacts with a tappet (30) and a spring, the armature plate (3) thereof being arranged to lie opposite an armature counterpiece (16), and said actuator (1) comprising at least one magnetostrictively-active component. According to the invention, an actuator (1) is provided with which large actuating paths can be travelled at high actuating forces. This is achieved by the actuator (1) additionally being designed to act as a solenoid.

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: 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 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: The metering servovalve (7) includes a valve body (8, 30), a shutter (45), and an electromagnet (15), and is housed inside a casing (2) of the injector (1). The electromagnet (15) activates a movable armature (16) performing a travel defined by a stop member (19) carried by the electromagnet (15), which is fixed inside the casing by a threaded ring nut (40) with the interposition of at least one deformable shim (48). The ring nut (40) is screwed to a predetermined tightening torque to a thread (46) on the casing (2) to elastically deform the shim (48). And the shim (48) is defined by a metal ring with, for example, an L-, C-, S-, Z- or ?-shaped cross section.

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: A fuel injector for an internal-combustion engine comprises an injector body and an injection-control valve, which in turn comprises: an open/close element; an elastic thrust element for pushing the open/close element; and a solenoid actuator, which can be actuated for exerting an action countering the thrust exerted by the elastic element. The solenoid actuator is formed by a monolithic assembly obtained in a mould, in which there is injected, on a core and a coil coupled to one another, a plastic material, which defines, once it has solidified, a body for insulation of the core from the injector body and which forms, once it has solidified, a monolithic assembly with the core and the coil.

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: 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: 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 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 injection system has a high-pressure pump (7) having at least one pumping element (18) operated reciprocatingly to perform an intake stroke and a delivery stroke. Each pumping element (18) has a corresponding intake valve (25) communicating with an intake conduit (10) supplied by a low-pressure pump (9). The intake conduit (10) is fitted with an on-off solenoid valve (27) controlled by a control unit (16) asynchronously with respect to the intake of each pumping element (18). And the control unit (16) may control the on-off solenoid valve (27) by means of frequency-modulated and/or duty-cycle-modulated control signals (A, C).

Abstract: An electroinjector is provided for controlling fuel injection in an internal-combustion engine. The electroinjector includes an electroactuator, an injection nozzle, and a pin, which is movable along an opening stroke and a closing stroke for opening/closing the nozzle under the control of the electroactuator and according to the supply pressure of the fuel into the electroinjector. A first electrical command and at least a second electrical command, which are sufficiently close to one another as to displace the pin with a profile of motion without any discontinuity in time, and such as to cause the pin to perform a first opening displacement and, respectively, a second opening displacement, are supplied to the electroactuator.