Abstract: A fuel-injection system (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?) 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 compressor mechanism (4) advantageously generates at least two distinct delivery lines (14), which are connected to respective distinct fractions (16) of the storage volume (7).

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: The pump (7) is provided with a body (16) having a compartment (17), and with at least one pumping element (13) that moves in a cylinder (12) in communication with the compartment (17), to raise the pressure of the fuel. The pump (7) comprises fluid-supply means (14, 22) for delivering the fuel to the pumping element (13), and an inlet mouth (26) made in the body (16) and supplied with the fuel coming directly from an external source (2). The inlet mouth (26) is fluidically connected to the compartment (17) to supply it with the fuel in order to lubricate and/or cool the pump (7) itself. Set between the inlet mouth (26) and the compartment (17) are: a non-return valve (33) to prevent in any case the pumping elements (13) from sucking the fuel from the compartment (17) of the body (16); and a flow regulator (29?), which allows an amount of fuel to pass such as to enable proper lubrication and cooling of the compartment (17) and of the parts present in the compartment (17).

Abstract: A fuel-injection system in an internal-combustion engine is provided with an electroinjector (1) comprising an injection nozzle (5), and a needle (7) mobile along an opening stroke and a closing stroke for opening/closing the nozzle (5) under the control of an electroactuator device (8). The opening stroke of the needle (7) is controlled by a rod (14) pushed by the pressure of the fuel in a control chamber (15), in such a way as to keep the needle (7) normally in the position for closing the nozzle (5). The control chamber (15) is equipped with an inlet duct (18) having a pre-set diameter (D4) and with an outlet passage (24) having a diameter (D5) and controlled by a control valve (16).

Abstract: The device comprises a connection tube (13) in communication with a hole (11) of a rail (7) for fuel under pressure, the tube (13) being provided with an end swelling (16). The device comprises a first threaded element (18) fixed to the rail (7) in a position corresponding to the hole (11) and a second threaded element (19) designed to engage the first threaded element (18). Removably set between the hole (11) and the swelling (16) is a seal element (21) designed to form a seal both with the hole (11) and with the swelling (16). The seal element (21) is a body of revolution (23) equipped with a passage (25) along a pre-set axis (A), and comprises two end noses (26, 27) designed to be inserted in the swelling (16) and in the hole (11), respectively, and two tapered seal stretches (28, 29).

Abstract: In order to reduce the size of a tubular rail for a high-pressure fluid, the rail is obtained from a hollow body with an external diameter and an internal diameter, and has two terminal portions, each provided with an external milling to favour gripping thereof. The millings have an external diameter such as to ensure, together with a cylindrical portion of a coaxial element, a radial strength at least equal to that of the hollow body. Made between the hollow body and each cylindrical portion is a front connection. For this purpose, the cylindrical portion has a plane front surface, whilst each terminal portion has an internal milling with an internal diameter greater than the internal diameter of the hollow body so as to house the cylindrical portion and so as to form an annular shoulder. A washer of softer material is set between the annular shoulder and the front surface.

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.

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: The injection system has a pump for supplying high-pressure fuel to a storage volume for supplying a number of injectors. The pump has at least one reciprocating pumping element performing a compression stroke synchronously with each fuel injection. The injection system has at least one control device for controlling the amount of fuel supplied by the pump to the storage volume, and which is controlled by a chopper control unit to modulate the fuel volume introduced into the compression chamber during the intake stroke (Ps-Pi). The delivery start instant of the pumping element during the compression stroke being unequivocally defined by the fuel volume introduced.

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: The high-pressure pump (7) comprises a number of pumping elements (18) actuated in reciprocating motion through corresponding suction and delivery strokes. Each pumping element (18) is provided with a corresponding intake valve (25) in communication with an intake pipe (10) supplied by a low-pressure pump (9). Set on the intake pipe (10) is an on-off solenoid valve (27) having a reduced flow rate substantially of the same order of magnitude as the maximum amount of fuel that can be injected by an injector (5). The solenoid valve (27) is controlled in a chopped way in synchronism with an intermediate part (32) of the suction stroke of each pumping element (18).

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 method is provided for controlling fuel injection in an internal-combustion engine provided with an electroinjector, including 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. The method supplies to the electroactuator 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.

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: The high-pressure pump (7) comprises a number of pumping elements (18) actuated in reciprocating motion through corresponding suction and delivery strokes. Each pumping element (18) is provided with a corresponding intake valve (25), in communication with an intake pipe (10), supplied by a low-pressure pump (9). Arranged on the intake pipe (10) is a shut-off valve (27) controlled in a choppered way in synchronism with an initial part (32; 32?) of the suction stroke of each pumping element (18).

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-injection system (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?) 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 compressor mechanism (4) advantageously generates at least two distinct delivery lines (14), which are connected to respective distinct fractions (16) of the storage volume (7).