Abstract: A mobile valve member designed to be arranged in the nozzle body of a fuel injector, extends along a main axis and includes a piston formed of a first male cylinder of effective diameter forming the top end of the mobile member and of a second cylinder provided with an internal cylindrical bore of the effective diameter and a shutoff member including a male cylindrical shaft of the effective diameter that fits slidingly in the internal bore, and of a member extending as far as a pointed end provided with a mobile seat and forming the bottom end of the mobile member. The mobile member is hydraulically balanced and the length between the top end and the bottom end thereof is variable as a result of the sliding of the cylindrical shaft in the internal bore of the piston.

Abstract: A fuel injector includes an injector body with a bore; an injector needle located within the bore and engageable with a needle seat to control fuel injection through an injector outlet; an armature member, the armature member being engageable with an armature seat on the injector needle, the injector needle in part and the armature member in part defining a control chamber; an actuator arrangement arranged to control fuel pressure within the control chamber such that fuel pressure variations within the control chamber controls movement of the injector needle relative to the needle seat wherein the actuator arrangement is arranged to be capable of moving the armature member from a seated position in which it engages the armature seat to an unseated position in which the armature member has moved relative to the armature seat in order to bring the control chamber into fluid communication with a low pressure drain.

Abstract: A coil assembly includes an electric coiling included in an overmold, the coiling being suitable to drive the control valve of a fuel injector. The coil assembly is provided with a longitudinal bore suitable for receiving a spring and with an adjusting member for the setting of the spring which can be moved from outside the injector, the adjusting member forming a transfer of movement such that the movement of the adjusting member from outside the injector is transformed into a compression of the spring.

Abstract: A control valve for controlling the movement of a needle of a fuel injector includes a coil which is attached to a housing of the injector, which housing engages with an armature which can be moved between an open position and a closed position. The armature includes a magnetic plate, through the center of which a rod, which forms a valve piston, extends perpendicularly to the plate to a remote end. The piston slides into a bore in the injector housing, the movements of the armature and of the piston opening or closing channels in which pressurized fuel flows. The armature is provided with a device for quickly discharging the fuel which is captive between the coil and the plate.

Abstract: A fuel injector includes an injection nozzle with a body, in which a needle moves between a closed position, in which a first end of the needle rests on a seat, and an open position, in which the first end of the needle is lifted from the seat. The fuel injector also includes a control chamber, a control valve, and an upper guide guiding the needle axially by the second end thereof. An electric link in contact with the second end of the needle bring the needle to a predetermined electric potential. The needle is mounted in the body so as to be able to move therein while being electrically isolated from the body, except for the region of the seat, so that the needle is in electric contact with the body only in the closed position.

Abstract: A mobile valve member designed to be arranged in the nozzle body of a fuel injector, extends along a main axis and includes a piston formed of a first male cylinder of effective diameter forming the top end of the mobile member and of a second cylinder provided with an internal cylindrical bore of the effective diameter and a shutoff member including a male cylindrical shaft of the effective diameter that fits slidingly in the internal bore, and of a member extending as far as a pointed end provided with a mobile seat and forming the bottom end of the mobile member. The mobile member is hydraulically balanced and the length between the top end and the bottom end thereof is variable as a result of the sliding of the cylindrical shaft in the internal bore of the piston.

Abstract: A coil assembly includes an electric coiling included in an overmold, the coiling being suitable to drive the control valve of a fuel injector. The coil assembly is provided with a longitudinal bore suitable for receiving a spring and with an adjusting member for the setting of the spring which can be moved from outside the injector, the adjusting member forming a transfer of movement such that the movement of the adjusting member from outside the injector is transformed into a compression of the spring.

Abstract: An electrical module for use within a fuel injector for delivering fuel to an internal combustion engine is described. The electrical module has a variable length. The electrical module comprises electrical contacts for operatively connecting the electrical module to a power plug of a fuel injector. The electrical module also comprises an actuator for operatively controlling a control valve disposed within the fuel injector. The electrical module also comprises electrical conductors arranged within a protective housing. These electrical conductors provide an electrical connection between the electrical contacts and the actuator in order to provide electrical power to the actuator when the electrical contacts are operatively connected to the power plug of the fuel injector. The body of the electrical module is comprised of a compressible elastic element, such that the length of the module is variable by compressing the elastic element. Injectors including such electrical modules are also described.

Abstract: A fuel injector includes fixed metal components, in particular an injector body, a solenoid actuator equipped with a retaining spring that holds a control valve stem, a control valve body including a seat for the control valve stem, a spacer between the body of the control valve and an injection nozzle, a control chamber, and an injection needle seat. The fuel injector also includes movable metal components, in particular the control valve stem and an armature thereof and an injection needle. Surfaces of the metal components that are in contact with one another are contact surfaces. Resistive surface coatings are arranged on a number of the contact surfaces. The overall electrical resistivity of the injector between the body of the solenoid actuator and the body of the injector varies by at least three distinct ohm values intermittently according to the kinetics of the injection needle of the injector.

Abstract: The present invention relates to a control valve for a fuel injector. The control valve has a control valve body which defines a supply passage for high pressure fuel. A control chamber and a pressure compensating chamber are provided in the control valve. The control chamber and the pressure compensating chamber are both in fluid communication with the supply passage. A control valve member is provided for controlling fuel pressure in the control chamber. The pressure compensating chamber is spaced radially outwardly from the control chamber. The invention also relates to a control valve member having a pressure compensating cavity.

Abstract: A control valve for controlling the movement of a needle of a fuel injector includes a coil which is attached to a housing of the injector, which housing engages with an armature which can be moved between an open position and a closed position. The armature includes a magnetic plate, through the center of which a rod, which forms a valve piston, extends perpendicularly to the plate to a remote end. The piston slides into a bore in the injector housing, the movements of the armature and of the piston opening or closing channels in which pressurized fuel flows. The armature is provided with a device for quickly discharging the fuel which is captive between the coil and the plate.

Abstract: A fuel injector includes fixed metal components, in particular an injector body, a solenoid actuator equipped with a retaining spring that holds a control valve stem, a control valve body including a seat for the control valve stem, a spacer between the body of the control valve and an injection nozzle, a control chamber, and an injection needle seat. The fuel injector also includes movable metal components, in particular the control valve stem and an armature thereof and an injection needle. Surfaces of the metal components that are in contact with one another are contact surfaces. Resistive surface coatings are arranged on a number of the contact surfaces. The overall electrical resistivity of the injector between the body of the solenoid actuator and the body of the injector varies by at least three distinct ohm values intermittently according to the kinetics of the injection needle of the injector.

Abstract: A fuel injector includes an injector body with a bore; an injector needle located within the bore and engageable with a needle seat to control fuel injection through an injector outlet; an armature member, the armature member being engageable with an armature seat; on the injector needle, the injector needle in part and the armature member in part defining a control chamber; an actuator arrangement arranged to control fuel pressure within the control chamber such that fuel pressure variations within the control chamber controls movement of the injector needle relative to the needle seat wherein the actuator arrangement is arranged to be capable of moving the armature member from a seated position in which it engages the armature seat to an unseated position in which the armature member has moved relative to the armature seat in order to bring the control chamber into fluid communication with a low pressure drain.

Abstract: A pressurized fuel injector includes a tubular body which forms a nozzle at one end such that fuel flows in the body between an inlet and the nozzle. A needle is arranged in the body and moves between an open nozzle position and a closed nozzle position, the fuel circulating in a space between the needle and the inner surface of the body, the needle being controlled according to a difference in pressure between a first control chamber into which the upstream end of the needle opens and the nozzle which is located downstream, the pressure in the first control chamber being regulated by a control valve operated by an electromagnet. The injector is provided with a complementary means for controlling the needle, the means engaging with the first control chamber such that the pressure of the fuel at the inlet is entirely transmitted to the injection nozzle.

Abstract: The present invention relates to a control valve for a fuel injector. The control valve has a control valve body which defines a supply passage for high pressure fuel. A control chamber and a pressure compensating chamber are provided in the control valve. The control chamber and the pressure compensating chamber are both in fluid communication with the supply passage. A control valve member is provided for controlling fuel pressure in the control chamber. The pressure compensating chamber is spaced radially outwardly from the control chamber. The invention also relates to a control valve member having a pressure compensating cavity.

Abstract: An electrical module for use within a fuel injector for delivering fuel to an internal combustion engine is described. The electrical module has a variable length. The electrical module comprises electrical contacts for operatively connecting the electrical module to a power plug of a fuel injector. The electrical module also comprises an actuator for operatively controlling a control valve disposed within the fuel injector. The electrical module also comprises electrical conductors arranged within a protective housing. These electrical conductors provide an electrical connection between the electrical contacts and the actuator in order to provide electrical power to the actuator when the electrical contacts are operatively connected to the power plug of the fuel injector. The body of the electrical module is comprised of a compressible elastic element, such that the length of the module is variable by compressing the elastic element. Injectors including such electrical modules are also described.