Abstract: A control servo valve is housed inside the casing of an internal combustion engine fuel injector, and has an actuator, a control chamber communicating with a fuel inlet and with a fuel outlet passage, and a shutter movable along an axis by the actuator between a closed position and an open position to close and open the outlet passage respectively; the servo valve also has a fixed axial rod interposed between the actuator and the control chamber; the outlet passage comes out through an outer lateral surface of the axial rod; and the shutter is defined by a sleeve which slides axially on the outer lateral surface, and, in the closed position, closes the outlet passage so as to be subjected to a zero axial resultant force by the pressure of the fuel.

Abstract: A fuel injector (1) for an internal-combustion engine has a shell (2) provided with two opposite terminal portions; the first terminal portion (4) has an inlet (7) for supply of the fuel and is generally designed to extend outside the engine, whilst the second terminal portion (5) has a nozzle (9) communicating with said inlet (7), is designed to be housed in the engine and has, in the radial direction, dimensions smaller than those of the first portion (4); the injector (1) further has an actuator (16) and a servo valve (15) housed in the first terminal portion (4); the servo valve (15) is provided with an open/close element (32), which can slide axially, under the action of the actuator (16) and substantially in a fluid-tight way, in a seat (27) and is subjected to an axial resultant of pressure of the fuel that is substantially zero; the fuel inlet (7) is made laterally in an intermediate axial position between the actuator (16) and the nozzle (9).

Abstract: A fuel-injection system (1, 1?, 1?, 1??) for an internal-combustion engine (2), of the type provided with compressor mechanism (4) for making available the fuel at a high pressure to an storage volume (7), and a plurality of injectors (8, 8?, 8??) fluidically connected to the storage volume (7) for taking in the fuel from the storage volume (7) and injecting it into respective combustion chambers (12) of the engine (2). The storage volume (7) is advantageously split into a plurality of distinct elementary storage volumes (9, 9?, 9a, 9b) fluidically connected to one another.

Abstract: A control servo valve (8) is housed inside the casing of an internal combustion engine fuel injector (1), and has an actuator (9), a control chamber (13) communicating with a fuel inlet (5) and with a fuel outlet passage (22), and a shutter (35) movable along an axis (3) by the actuator (9) between a closed position and an open position to close and open the outlet passage (22) respectively; the servo valve (8) also has a fixed axial rod (29) interposed between the actuator (9) and the control chamber (13); the outlet passage (22) comes out through an outer lateral surface (30) of the axial rod (29); and the shutter (35) is defined by a sleeve which slides axially on the outer lateral surface (30), and, in the closed position, closes the outlet passage (22) so as to be subjected to a zero axial resultant force by the pressure of the fuel.

Abstract: The metering servovalve (7) comprises a valve body (8, 30), an open/close element (45) and an electromagnet (15), and is housed in a casing (2) of the injector (1). The electromagnet (15) actuates a mobile armature (16) for a travel defined by a polar surface (19) of the core (18) of the electromagnet (15). This latter is fixed in the casing (2) by means of a threaded ring nut (40), with the interposition of at least one deformable adjustment shim (48). The ring nut (40) is screwed with a pre-set tightening torque on a thread (46) of the casing (2) so as to bring about an elastic deformation of the adjustment shim (48) and to prevent accidental unscrewing of the ring nut (40). The adjustment shim (48) is constituted by a metal ring with a cross section having a shape chosen between L, C, S, Z, and ?.

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: An internal combustion engine fuel injector (1) has a rod (10) movable along an axis (3) to open/close a nozzle, and a servovalve (7) having a control chamber (23) with a discharge passage (26) which is opened/closed by a shutter (17) movable axially under the control of an electro-actuator (14); the servovalve (7) also has a fixed axial rod (33) having an outer lateral surface (34) through which the discharge passage (26) comes out; the shutter (17) is fitted to the axial rod (33) to slide axially in substantially fluidtight manner, and, when closing the discharge passage (26), is subjected to substantially zero resultant axial pressure by the fuel; and the control chamber (23) is bounded radially by a tubular portion (8) formed in one piece with said axial rod (33).

Abstract: An internal combustion engine fuel injector (1) has a rod (10) movable along an axis (3) to open/close a nozzle, and a servovalve (7) having a control chamber (23) with a discharge passage (26, 48) which is opened/closed by a shutter (17) movable axially under the control of an electro-actuator; the servovalve also has a fixed axial rod (33) having an outer lateral surface (34) through which the discharge passage (26, 48) comes out; the shutter (17) is fitted to the axial rod (33) to slide axially in substantially fluidtight manner, and, when closing the discharge passage (26, 48), is subjected to substantially zero resultant axial pressure by the fuel; and a calibrated portion (42, 52) of the discharge passage (26, 48) is formed close to the outlet of the discharge passage to produce swirl and/or cavitation in the fuel outflow near to the closing area between the shutter (17) and the axial rod (33).

Abstract: A fuel injector for an internal-combustion engine houses, in a hollow injector body of its own, an injection-control valve, the valve body of which delimits, together with the injector body, an annular chamber designed to receive a fuel under pressure, and insulated in a fluid-tight way by a seal member carried by the valve body and made of plastic material.

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: A fuel-injection system (1, 1?, 1?, 1??) for an internal-combustion engine (2), of the type provided with: a tank (3) for collection of the fuel; compressor system (4) for drawing in the fuel from the tank (3) and making it available at high pressure to an storage volume (7); at least one injector (8, 8?, 8??) hydraulically connected to the storage volume (7) for taking in the fuel at a high pressure from the storage volume (7) and injecting it into a respective combustion chamber (12) of the engine (2); a fluid line (17) connecting the storage volume to the tank; and pressure-regulator means (19) in the storage volume (7) set along the fluid line (17); the pressure-regulator systems (19) are set hydraulically downstream of the storage volume (7) so as to enable a continuous flow of fuel through the storage volume (7) itself.

Abstract: A control servo valve (8) is housed inside the casing (2) of an internal combustion engine fuel injector (1), and has a piezoelectric actuator (40), and a control chamber (13) having a fuel outlet passage (21); the outlet passage (21) comes out inside an annular chamber (34) defined by a fixed tubular portion (25) and by a shutter (32), which engages the tubular portion (25) in substantially fluidtight manner and is slid axially by the piezoelectric actuator (40) from a closed position, in which it closes the annular chamber (34) and is subjected to a zero axial resultant force by the fuel pressure, to an open position, in which the outlet passage (21) communicates with a discharge conduit.

Abstract: A fuel-injection system (1, 1?, 1?, 1??) for an internal-combustion engine (2), of the type provided with compressor mechanism (4) for making available the fuel at a high pressure to an storage volume (7), and a plurality of injectors (8, 8?, 8??) fluidically connected to the storage volume (7) for taking in the fuel from the storage volume (7) and injecting it into respective combustion chambers (12) of the engine (2). The storage volume (7) is advantageously split into a plurality of distinct elementary storage volumes (9, 9?, 9a, 9b) fluidically connected to one another.

Abstract: A control servo valve (8) is housed inside the casing of an internal combustion engine fuel injector (1), and has an actuator (9), a control chamber (13) communicating with a fuel inlet (5) and with a fuel outlet passage (22), and a shutter (35) movable along an axis (3) by the actuator (9) between a closed position and an open position to close and open the outlet passage (22) respectively; the servo valve (8) also has a fixed axial rod (29) interposed between the actuator (9) and the control chamber (13); the outlet passage (22) comes out through an outer lateral surface (30) of the axial rod (29); and the shutter (35) is defined by a sleeve which slides axially on the outer lateral surface (30), and, in the closed position, closes the outlet passage (22) so as to be subjected to a zero axial resultant force by the pressure of the fuel.

Abstract: A fuel injector has an injector body extending along a given axis; a tubular valve body housed inside a hole in the injector body and coaxial with the injector body; and an annular chamber defined by the injector body and the valve body. The method of producing the injector includes connecting the valve body to the injector body, and fixing the valve body in a given position along the axis with respect to the injector body by means of a driving operation to interference fit the valve body inside the hole in the injector body.

Abstract: The injector has a hollow body supporting an ordinary injection nozzle and a metering valve for metering the fuel to be injected; and a support defined by a sleeve and by an end wall. The sleeve houses an electromagnet controlling the metering valve, and is fitted to the hollow body. For which purpose, there is provided a leaf spring having a ring-shaped portion engaging the end wall of the support; and a number of elastic blades, each terminating with a hook-shaped appendix which engages a corresponding retaining element on the hollow body.

Abstract: A fuel injector has an injector body extending along a given axis; a tubular valve body housed inside a hole in the injector body and coaxial with the injector body; and an annular chamber defined by the injector body and the valve body. The method of producing the injector includes connecting the valve body to the injector body, and fixing the valve body in a given position along the axis with respect to the injector body by means of a driving operation to interference fit the valve body inside the hole in the injector body.

Abstract: A fuel injector has an injector body extending along a given axis; a tubular valve body housed inside a hole in the injector body and coaxial with the injector body; and an annular chamber defined by the injector body and the valve body. The method of producing the injector includes connecting the valve body to the injector body, and fixing the valve body in a given position along the axis with respect to the injector body by means of a driving operation to interference fit the valve body inside the hole in the injector body.

Abstract: The injector has a hollow body housing a fuel metering valve closed by a closing spring; and a support housing an electromagnet controlling an armature. The support is connected to the hollow body, and the armature provides for opening the valve. The armature is fitted inside the hollow body by means of a leaf spring hinge having an annular portion fixed between the hollow body and the support, and a projecting radial tongue fixed to a central portion of the armature. The tongue, together with at least one radial appendix of the leaf spring hinge, provides for arresting the armature with a predetermined clearance with respect to the core of the electromagnet.

Abstract: The injector has a hollow body housing a fuel metering valve closed by a closing spring; and a support housing an electromagnet controlling an armature. The support is connected to the hollow body, and the armature provides for opening the valve. The armature is fitted inside the hollow body by means of a leaf spring hinge having an annular portion fixed between the hollow body and the support, and a projecting radial tongue fixed to a central portion of the armature. The tongue, together with at least one radial appendix of the leaf spring hinge, provides for arresting the armature with a predetermined clearance with respect to the core of the electromagnet.