Abstract: A gaseous fuel injection valve includes: a valve housing; a metallic nozzle member having a flat valve seat and a nozzle bore passing through a central portion of the valve seat; a valve body provided at one end face with a rubber seating member which is operated in cooperation with the valve seat; a coil; and a return spring for urging a stationary core and the valve body toward the valve seat. The stationary core attracts the valve body to move the seating member away from the valve seat, when the coil is excited. In this injection valve, a fluorine resin valve seat coating is formed on the valve seat so that the seating member is brought into close contact with the valve seat coating. Thus, an oil-repellent property of the valve seat coating is provided to the valve seat to prevent adherence of oil to the valve seat, leading to an improvement in valve-opening response of the valve body upon the excitation of the coil.

Abstract: An improved fuel injection spray director plate including conically chamfered entries to the flow passages through the plate. The conical chamfer may extend part way or all the way through the plate. In a currently preferred embodiment, the chamfer extends only part way through the plate, and the remaining cylindrical portion of the passage provides desirable directional capability for the spray. Preferably, the conical chamfer axis forms an angle with the cylindrical portion axis. Preferably, a flow passage is positioned in the director plate such that the main flow direction of fuel exiting the fuel injector valve is received into the chamfer of the passage. Preferably, a second conical portion is formed in the passage between the first conical portion and the cylindrical portion.

Abstract: An injector has a lift limiting member provided by a single plate member. The plate member has a stopper face, multiple hole sections, a flow passage hole, and a spring seat face. An axial end face of a needle head section of a needle contacts the stopper face when the needle lifts by a predetermined amount. Transmitting sections of a pressurizing piston are loosely inserted in the hole sections. High pressure fuel can pass through the flow passage hole. The spring seat face receives an end portion of a spring that biases the needle in a valve closing direction. The lift limiting member limits a valve opening lift position of the needle, so a stable injection quantity is obtained. Thus, a surface area of the single plate member can be used in multiple functions.

Abstract: A fuel injection device for fuel injection systems, e.g. for aircraft gas turbines, includes at least one fuel injection opening, through which a continuous flow of fuel 1 is issued, with the fuel injection opening having a non-circular cross-section.

Abstract: A fuel injector is provided having a needle valve element and a nozzle member with a central bore configured to slidingly receive the needle valve element. The fuel injector also has a spring configured to bias the needle valve element toward a closed position. In addition, the fuel injection assembly has a guide element configured to reduce a lateral movement of the needle valve element. The fuel injection assembly further has a fluid flow restricting device configured to restrict the flow of a fluid through the needle valve element and create a fluid pressure differential between the fluid upstream and downstream of the fluid flow restricting device.

Abstract: The invention relates to a dosing device for liquid fuels, in particular for the supply into a chemical reformer to obtain hydrogen, or into a postcombustion device to produce heat. The dosing device has at least one metering device to meter fuel into a metering line, and a conditioning unit, which abuts the metering line and delivers the fuel into a metering chamber. The conditioning unit is designed as a purely mechanical valve, which opens and closes at a frequency of approximately 1500 Hz.

Abstract: A fuel injector for the direct injection of fuel into a combustion chamber of an internal combustion engine includes an energizable actuator, a valve needle, which is in operative connection with the actuator and acted upon by a restoring spring in a closing direction to actuate a valve-closure member, which forms a sealing seat together with a valve-seat surface formed at a valve-seat body. The valve-seat body includes at least two spray-discharge orifices. The pressure of the fuel flowing through the fuel injector is greater than 10 bar.

Abstract: An electronic unit injector comprising a spray tip including a valve seat, a needle valve arranged to close on the seat to prevent discharge of fuel from the spray tip or to open off the seat to dispense fuel from the spray tip, a spring biasing the needle valve to a closed position, a spring seat between the spring and the needle valve, the needle valve overcoming the biasing force when the pressure reaches a predetermined level, the spring and seat being disposed in a cage having port areas circumferentially arranged about said spring and spring seat to supply low pressure fuel to the area occupied by said spring and spring seat to reduce the risk of cavitation in said spring cage.

Abstract: A nozzle for a low pressure fuel injection that improves the control and size of the spray angle, as well as enhances the atomization of the fuel delivered to the cylinder for an engine, at relatively low pressures. The nozzle includes a metering plate having inner and outer exit cavities in rings spaced circumferentially about a center exit cavity.

Abstract: A fuel injector with various embodiments of a annular damper member that reduces noise generated between a valve group subassembly and a power group subassembly during operation of the fuel injector. A mass annular damper member is also shown and described. A method of reducing sound in the valve group subassembly is also disclosed.

Abstract: In a method for detaching a plurality of ceramic components (11-15) from a ceramic component block (1), the following steps are provided: providing the component block (1); mounting a plurality of parallel wire segments (21-26) in a frame (3) to form a saw frame (2); and sawing the provided component block (1) into the plurality of components (11-15) using the saw frame (2).

Abstract: A fuel injection system having one high-pressure fuel pump and one fuel injection valve, communicating with the high-pressure fuel pump, for each cylinder of an internal combustion engine. A pump work chamber is defined by a pump piston, and the fuel injection valve has an injection valve member by which at least one injection opening is controlled. An electrically actuated control valve controls a communication of the pump work chamber with a relief region and a movable control piston acts at least indirectly in the closing direction on the injection valve member, and the control piston, on its side remote from the at least one injection valve member, is acted upon at least indirectly by the pressure prevailing in the pump work chamber. The control piston, with its side toward the injection valve member, defines a control chamber.

Abstract: A fuel injection valve has a first groove cut in a peripheral surface of a needle valve and second grooves cut in a seat surface of a nozzle tip. The first groove is provided so that the needle valve is rotated by flow of the fuel in the first groove caused by a reciprocating motion of the needle valve, and upper and lower ends of the first groove are opened to the outside so that the fuel can be introduced into the groove. The second grooves are twisted or tilted in the same direction as the rotating direction of the needle valve and are cut along the circumferential direction of the nozzle tip. The second grooves have an edge part for scraping off solid matters into the second grooves in cooperation with the tip seat surface of the needle valve by the rotation of the needle valve.

Abstract: A fuel injection valve includes a valve chamber, a control valve, an actuator, a control chamber, and a nozzle. The control valve is provided in the valve chamber. The actuator actuates the control valve. The control chamber is always communicated with the valve chamber through a communication passage. The nozzle has a needle for opening and closing an injection orifice, wherein the needle is biased in a valve closing direction for closing the injection orifice by pressure of fuel in the control chamber. High pressure fuel in a high-pressure fuel passage is introduced into the control chamber only through the communication passage in a state, where communication between the valve chamber and the high-pressure fuel passage is allowed by the control valve. The communication passage has a common orifice.

Abstract: A needle is received in a nozzle body and is adapted to reciprocate relative to an injection hole to open and close the injection hole. A pressure chamber receives the fuel and exerts a pressure against the needle in an opening direction away from the injection hole upon increasing of the pressure of the fuel in the pressure chamber. A damper arrangement is actuated upon increasing of the pressure in the pressure chamber to alleviate a change in the pressure in the pressure chamber. A pressurizing piston reciprocates to increase and decrease the pressure of the fuel in the pressure chamber.

Abstract: A fuel injector with direct triggering of an injection valve member in which an actuator is received in the hollow chamber which is subjected to fuel that is at high pressure via a high-pressure source disposed outside the fuel injector. The actuator is supplied with current in the closing position of the injection valve member and is not supplied with current in the open position of the injection valve member. The actuator acts directly on a booster piston of a pressure booster, which booster piston acts upon the booster chamber. A control chamber sleeve defining a control chamber is movably received in the booster piston.

Abstract: A fuel injection valve is provided that includes a valve seat member (3) having a conical valve seat (8) and a valve hole (7) formed through a central part of the valve seat (8), a valve body (18) working in cooperation with the valve seat (8), and an injector plate (10) joined to the valve seat member (3) and having a plurality of fuel injection holes (11) radially outwardly displaced from the valve hole (7), a diffusion chamber (39) providing communication between the valve hole (7) and the fuel injection holes (11) being provided between the valve seat member (3) and the injector plate (10), wherein the diffusion chamber (39) formed between the valve seat member (3) and the injector plate (10) is in an annular shape, has a diameter that is larger than that of the valve hole (7), and has inner ends of the fuel injection holes (11) opening therein, and a plurality of fuel passages (42a, 42b) are disposed within the valve hole (7), the plurality of fuel passages (42a, 42b) reversing within the valve hole (7)

Abstract: A fuel injector assembly for an emissions-based EMD 710 locomotive dieselengine. The fuel injector assembly includes a needle slidably positioned within a bore of a valve body of the injector assembly, where fuel pressure introduced into a bore chamber causes the needle to open a spray tip. A spring mounted within the bore forces the needle to close the spray tip when the fuel is not being applied. The spring is a dead coil spring including inactive coils where at least portions of the coils at both ends of the spring are in intimate contact with each other so as to reduce spring wear during operation of the assembly. Because the dead coil spring has reduced wear, the VOP set point of the fuel injector assembly can be reduced, which reduces NOx emissions.

Abstract: A fuel injector for use with LPG or other volatile fuels has fuel inlets through a cylindrical wall of a valve group tube assembly. Fuel venting is along a longitudinal axis of the fuel injector to an end opposite the injection end. An O-ring retaining cup is welded to the tube assembly above and below the fuel inlets to seal these members and to maintain alignment of holes in the cup with the fuel inlets.

Abstract: A method for fabricating a fuel nozzle assembly includes providing a nozzle portion including a fuel passageway defined about a center axis of the fuel nozzle assembly. A longitudinal axis of a first peg is oriented to intersect the fuel nozzle assembly center axis such that a first plane is defined. The first peg defines a first opening having a centerline intersecting the first peg longitudinal axis and obliquely oriented with respect to the first plane. The first peg is coupled in flow communication with the fuel passageway such that the first peg extends radially outward from the nozzle portion and such that the first opening is configured to direct a flow of fuel in an oblique direction with respect to the fuel nozzle assembly center axis to facilitate fuel mixing.

Abstract: A fuel injector is disclosed. The fuel injector includes an injector valve needle and a valve actuation assembly including a stator, an armature, and a valve, the valve in fluid communication with the injector valve needle. A stator protection device is positioned between the stator and at least a portion of the armature. The stator protection device is configured to prevent contact between the stator and the armature.

Abstract: The invention relates to an injection valve, comprising a control chamber (15) with a control piston (16) that is functionally linked with a nozzle needle (35). The control chamber (15) is linked, via an inlet throttle (13), with pressurized fuel, and with an outlet throttle (14) with a valve chamber (9). A servo valve (5) is disposed in the valve chamber (9), said servo valve opening a connection between the valve chamber (9) and a return element (40) depending on its position. The inventive injection valve further comprises a bypass throttle (12) that is interposed between the fuel feed line and the valve chamber.

Abstract: The fuel injector including an orifice plate which is provided with a multitude of outlet openings and situated downstream from a valve-seat body having a fixed valve seat. Directly upstream from the outlet openings is an inflow opening having an annular inflow cavity. The valve-seat body covers the inflow cavity in such a way that the downstream outlet openings of the orifice plate are covered. The outlet openings each have an inflow region whose diameter D1 is considerably larger than the diameter D2 of a region that abuts at a sharp angle directly downstream therefrom, which forms the narrowest cross section of the outlet opening and from where the outlet opening widens in the flow direction to a diameter D3 in a trumpet-shaped manner. The fuel injector may be particularly suitable for use in fuel injection systems of mixture-compressing ignition engines having externally supplied ignition.

Abstract: A fuel injection valve in which, even in an engine in which a fuel containing many foreign matters is used, pinching of solid foreign matters, such as impurities, dirt and dust, and combustion residues, in a sliding part on the outer periphery of a needle valve, the tip of the needle valve, and a seat of a nozzle tip, malfunction an seizure of the needle valve due to such containing, and poor combustion due to irregular injection are prevented from occurring. The fuel injection valve has a first groove cut in the periphery surface of the needle valve and the second grooves cut in a seat surface of the nozzle tip. The first groove is provided so that the needle valve is rotated by flow of the fuel in the first groove caused by reciprocating motion of the needle valve, and the upper and lower ends of the first groove are opened to the outside so that a part of fuel can be introduced in to the groove.

Abstract: A support assembly for a piezoelectric actuator (15), in particular for a piezoelectric actuator for driving an injector for the injection system of an internal combustion engine has a holder (5-10) for spatially securing a piezoelectric stack (2) and two associated connection pins (11, 12) for electrically contacting the stack (2). The support assembly is configured as a single support, which only holds a single piezoelectric stack (2) with two associated connection pins (11, 12).

Abstract: A control valve assembly includes a one-piece valve movable between a first position at which the valve closes a seat defined by a housing and positioned fluidly between a fluid inlet and a first fluid outlet, and a second position at which the valve is out of contact with the seat. The valve includes an outer diameter having an annular seating shoulder located thereon which is configured to contact a frustoconical surface of the seat when the valve is at the first position, and the annular seating shoulder is further configured to deform in response to contacting the frustonical surface without changing a seating diameter associated therewith. Closing the seat with the annular seating shoulder reduces performance variability of the valve over time.

Abstract: An injector with an adjustable-metering servo valve is provided. The injector has a shutter actuated by an armature of an electromagnet. The armature is mobile for an opening stroke defined by a surface of the core of the electromagnet, which is fixed in the casing by a ring nut and a hollow support of the core. The hollow support has a first contact surface that acts on a flange of the core. Set between the surface and a shoulder of the casing is a shim. An annular projection, having a second contact surface, is set between the surface and a shoulder of the casing. The second contact surface is contained at least in part in the area corresponding to the first contact surface so that the stroke of the armature is adjusted by plastic deformation of the shim or of the surface of the core.

Abstract: A fuel injector has a housing extending along a longitudinal axis between an inlet and an outlet. The housing has an elongated member connected to a body by a thin shell connector member with a stepped portion. The connector member has a generally constant thickness with a first internal volume and a second internal volume where the second internal volume is at least 1.1 times the first internal volume.

Abstract: Embodiments for minimizing relative thermal growth within a fuel nozzle of a gas turbine combustor are disclosed. Fuel nozzle configurations are provided in which a heating fluid is provided to one or more passages in a fuel nozzle from feed holes in the fuel nozzle base. The heating fluid passes through the fuel nozzle, thereby raising the operating temperature of portions of the fuel nozzle to reduce differences in thermal gradients within the fuel nozzle. Various fuel nozzle configurations and passageway geometries are also disclosed.

Abstract: In a control system and method for operating an ultrasonic liquid delivery device a first drive signal is delivered according to a first drive signal control schedule to an ultrasonic waveguide assembly to excite the ultrasonic waveguide for a predefined time. At each of a plurality of instances of the first drive signal control schedule a phase angle associated with the current and voltage in the waveguide assembly during ultrasonic vibration thereof is determined. A second drive signal control schedule is determined, including a second ultrasonic drive signal frequency for each of the instances at which the phase angle of the first drive signal was determined. The second drive signal frequency at each of the instances is based at least in part on the phase angle determined at each instance during ultrasonic vibration of the waveguide assembly in accordance with the first drive signal control schedule.

Abstract: In a fuel injection valve, a fuel guide member facing the valve hole is connected to an injector plate, and an annular diffusion chamber is formed between a valve seat member and the injector plate. A pair of first notches, a pair of second notches, and a plurality of closing parts are formed in an outer periphery of the fuel guide member. The first notches are arranged on a first diameter line of the valve hole. The second notches are arranged on a second diameter line perpendicular to the first diameter line. The closing parts are provided between the first and second notches to partially close the valve hole. A plurality of fuel injection holes are dispersally arranged in outside regions corresponding to the closing parts and inside regions corresponding to the first notches.

Abstract: A method for producing a fuel injector and a fuel injector for internal combustion engines, having a control valve with an electromagnetically actuatable valve needle; a coil is received in a magnet cup made of magnetizable material. At least one clamping sleeve, with a slot extending between the face ends of the clamping sleeve, is received in the magnet cup.

Abstract: An injection nozzle (4) for an internal combustion engine, the injection nozzle (4) including a nozzle body (6) provided with a bore (8) defining a valve seating surface, and having a first nozzle outlet and a second nozzle outlet, a first delivery chamber upstream of said nozzle outlets, an outer valve member, moveable within the bore (8) and itself provided with an axial bore (8), wherein the outer valve member is engageable with an outer valve seat defined by the valve seating surface so as to control fuel flow from a first delivery chamber to at least the first nozzle outlet when the outer valve member lifts from its seat.

Abstract: A low pressure fuel injector capable of atomizing fuel at relatively low pressure is configured to have reduced hydraulic resistance. Reduction in the hydraulic resistance minimizes the pressure drop within the fuel injector and thereby improves atomization of the fuel for improved fuel economy and performance, and decreased emissions.

Abstract: In an actuator unit, the piezo actuator (1) is located inside a tubular spring (3) under pre-stress. To compensate the thermal length modifications of the piezo actuator (1) in relation to the actuator housing (4, 3, 6, 5), the compensation element is configured as an aluminium compensation cylinder (2) that is situated in an extension tube (6). The piezo actuator (1) and the compensation cylinder (2) are mounted in series and conjointly pre-stressed by means of the tubular spring (3) that is extended in relation to the actuator housing by the extension tube (6).

Abstract: A control system for a fuel injector is disclosed. The control system has a nozzle member with at least one orifice, and a needle check valve. The needle check valve is recipratingly disposed to open and close the at least one orifice. The control system also has a control chamber located at the base end of the needle check valve, and a control valve movable to selectively drain and fill the control chamber. The control system further has an injector body, a first piston located within the injector body, and a second piston located within the injector body. The first piston is operatively connected to the control valve to move the control valve. The second piston is located a distance from the first piston to form a coupling chamber. The control system additionally has a partial-ball check valve associated with the coupling chamber to selectively replenish the coupling chamber.

Abstract: A coating for fuel injector components adapted for use with low lubricity fuels is disclosed. The invention consists of a metal carbon material coating or a metal nitride coating to the fuel pump plunger or other fuel injection system components. The invention utilizes a coating on the fuel injector plunger that minimizes scuffing or seizure associated with the plunger and barrel.

Abstract: A method of controlling wear in a fuel injector assembly is provided. The method can include selecting an injector assembly including a fuel injector plunger including a plunger substrate material and a first coating on the plunger substrate material, and a fuel injector bore including a bore substrate material and a second coating on the bore substrate material. The first and second coatings of the plunger and bore are in sliding engagement and can include chromium nitride. Fuel may be supplied to the bore assembly using a fuel that includes at least one of an ultra-low sulfur fuel and a low lubricity fuel.

Abstract: A nozzle clamping nut for an injection valve comprises two sections in the longitudinal direction, having different-sized free inner diameters (D1, D2). A shoulder forms a bearing surface (9) in a transition region between the first and second sections, extending in a circular manner perpendicularly to the longitudinal direction. The nozzle clamping nut has a large bearing surface with low stress concentration. The nozzle clamping nut consists of an inner tube (3) and an outer tube (1) which have different-sized inner diameters (D1, D2), which fit inside each other and which are connected to each other in a fixed manner, and the bearing surface (9) is formed by the annular front surface of the inner tube (3).

Abstract: A fuel injector nozzle assembly is disclosed. The assembly may include a nozzle casing, a first tip member, and a second tip member. The first tip member may extend longitudinally within the nozzle casing and may define first and second shoulders on the first tip member. The second tip member may extend longitudinally within the nozzle casing and may be arranged in predetermined rotational alignment with the first tip member. The second tip member may define a third shoulder on the second tip member configured to interact with the first shoulder to oppose rotation of the first tip member relative the second tip member in a first direction about a longitudinal axis of the first tip member. The second tip member may further define a fourth shoulder on the second tip member configured to interact with the second shoulder to oppose rotation of the first tip member relative the second tip member in a second direction about a longitudinal axis of the first tip member.

Abstract: A fuel injector is described. The fuel injector includes an inlet, outlet, seat, closure member, and a metering orifice disc. The metering orifice disc is disposed between the seat and the outlet. The metering orifice disc includes: a generally planar surface, a plurality of metering orifices that extends through the generally planar surface, the metering orifices being located radially outward of the seat orifice; and at least one flow channel having a cross-sectional area that decreases in magnitude starting at a location spaced from the longitudinal axis to proximate a perimeter of a metering orifice. A seat subassembly and a metering orifice disc are described. And a method of atomizing fuel is also described.

Abstract: A fuel injector tip seal is provided including improved resistance to the heat and pressures of combustion gas. According to one aspect, the tip seal is formed from polytetrafluoroethylene and between 10 and 35 percent carbon fiber. The material offers improved surface finish and deformation resistance as well as improved thermal conduction and keeps thermal expansion low as compared to conventional fuel injector tip seal designs. According to a further aspect, a revised seal groove design is provided that allows for expansion and deformation of the tip seal and creates more pressure to the outside diameter face when pressure is applied at the tip. According to another aspect, the tip seal is formed of a flat disk-shaped seal body that can be assembled on the fuel injector by an assembly cone device that allows the disk-shaped seal body to be flipped to a ring-shaped configuration in its assembled position.

Abstract: The present invention provides methods and apparatus for injecting reagent, such as an aqueous urea solution, into an exhaust stream in order to reduce oxides of nitrogen (NOx) emissions from diesel engine exhaust The present invention uses mechanical spill return atomization techniques to produce droplets approximately 50 ?m SMD (Sauter mean diameter) or smaller. This size range is appropriate to allow urea to react into ammonia within the residence time associated with an on-road diesel engine. This effect is achieved through the use of a whirl plate having a plurality of whirl slots surrounding an exit orifice of the injector, which produce a high velocity rotating flow in the whirl chamber. When the rotating flow of reagent is passed through the exit orifice into an exhaust stream, atomization occurs from a combination of centrifugal force and shearing of the reagent by air as it jets into the exhaust stream.

Abstract: An electrically operated injector (1) for feeding a gaseous fuel to a cylinder of an internal combustion engine, in particular for a motor vehicle, includes an electromagnetic actuator (2) acting on a mechanical interceptor member (3) arranged to free or intercept a passage (4) for the fuel from a feed conduit (61) to a delivery conduit (5) connected to an outlet (6), between the delivery conduit (5) and the interceptor member (3) there being positioned a seal element (40). This latter is carried by the interceptor member (3) and has a shape tapering towards the delivery conduit (5) in order to effectively intercept the fuel gas passage (4) and minimize the area of impact with an annular end portion (43) of the delivery conduit (5).

Abstract: Fuel injectors having control passages with relatively large volumes may have limited responsiveness. The injector described herein may help to reduce the control passage volume and improve responsiveness by providing a chamber for receiving a fluid, a control valve, a flow passage, and an insert. The control valve may be moveable between a first position and a second position. The flow passage may extend between the control valve and the chamber, and the flow passage may define a first volume. The insert may be located within the flow passage, and the insert may occupy a second volume. The placement of the insert within the flow passage reduces the volume of the flow passage that is available to receive the fluid to a third volume equal to the first volume less the second volume.

Abstract: A fuel injection valve with a valve member axially displaceable in a bore of a valve body comprises a valve stem, the combustion chamber end, with which it interacts with a valve face of the valve body, at least one injection opening downstream of the valve face and opening into the combustion chamber to be supplied with fuel, a guide section of the valve body guiding the valve member and being disposed axially between an annular gap connected to the high-pressure fuel line and an annular space leading to the valve face, a first throttle connection permanently interlinking the annular gap and the annular space, and a second throttle connection interlinking the annular gap and the annular space as of a defined opening stroke of the valve member and having a smaller throttle resistance than the first throttle connection. The guide section is configured by a guide sleeve that is fastened at the combustion chamber end of the valve body in the bore so as to be stationary.

Abstract: A fuel injector for delivering fuel to an engine in which a housing of the injector has an internal fuel chamber and at least one exhaust port in fluid communication with the fuel chamber. A valve member is moveable relative to the housing between a closed position in which fuel within the fuel chamber is inhibited against exhaustion from the housing, and an open position in which fuel is exhaustable from the housing. An ultrasonic waveguide is separate from the housing and valve member. The ultrasonic waveguide is elongate and has longitudinally opposite ends. The waveguide further has a first waveguide segment and a second waveguide segment. The first and second segments are disposed entirely within the fuel chamber of the housing. An excitation device is operable in the open position of the valve member to ultrasonically excite the ultrasonic waveguide.

Abstract: An injection valve (1) can be fitted into a cavity (4) of a cylinder head (5) of an internal combustion engine. The valve has at least one injection orifice (6) and a nozzle body (2) with a nozzle body shaft (8). The nozzle body shaft (8) has a coupling element (11), which projects radially from the nozzle body shaft (8) and when the injection valve (1) has been fitted, mechanically couples the nozzle body shaft (8) to the lateral area (10) of the cavity (8) of the cylinder head (5) in a radial direction.

Abstract: A fuel injector with various embodiments of a annular damper member that reduces noise generated between a valve group subassembly and a power group subassembly during operation of the fuel injector. A mass annular damper member is also shown and described. A method of reducing sound in the valve group subassembly is also disclosed.

Abstract: A fuel injector having a piezoelectric actuator in an injector body and held in contact with the injector body on one side and with a sleevelike booster piston on the other via first spring means. A nozzle body joined to the injector body and a stepped nozzle needle is guided in the body. A second spring disposed inside the booster piston which together with the injection pressure acting on the back side of the nozzle needle keeps the nozzle needle in the closing position. A control chamber on the end toward the nozzle needle of the booster piston communicates, via at least one leakage gap with a fuel supply at injection pressure, and the nozzle needle is urged in the opening direction by the fuel located in the control chamber.