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: 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 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: 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: 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: 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 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-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 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: 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 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 device includes a connection tube in communication with a hole of a rail for fuel under pressure, the tube being provided with an end swelling. The device has a first threaded element fixed to the rail in a position corresponding to the hole and a second threaded element designed to engage the first threaded element. Removably set between the hole and the swelling is a seal element designed to form a seal both with the hole and with the swelling. The seal element is a body of revolution equipped with a passage along a pre-set axis, and includes two end noses designed to be inserted in the swelling and in the hole, respectively, and two tapered seal stretches.

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 injection system (1) comprises a pump (7) designed to send fuel at high pressure to an accumulation volume, for example formed by a common rail (6), for supplying a plurality of injectors (5). The pump (7) comprises at least one pumping element (18) actuated with reciprocating motion with a compression stroke (Pi-Ps) at a sinusoidal speed (24), in synchronism with each step of fuel injection. The injection system (1) comprises at least one by-pass solenoid valve (14), which is controlled by a chopper control unit (16, 28) for modulating the delivery of the pumping element (18) by varying both the instant of start (To) and the instant of end (T1) of delivery during the compression stroke (Pi-Ps), in such a way that the delivery is synchronous with the injection phase.

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 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 (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: 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.