Abstract: The invention relates to an injection valve (1) for injecting fuel into the combustion chamber of an internal combustion engine. The injector needle (17) of the injection valve (1) is guided inside the housing in such a way that it can be displaced longitudinally with a shaft (19) in order to open and close the injection cross-sections. The injector needle (17) is actuated by the fuel pressure which acts upon the injector needle and by a closing spring (16) acting in the closing direction of the injector needle. The closing spring (16) is pre-compressed between abutments on the injector needle (17) and the housing and is situated on the perimeter of the injector needle in the area between the injector needle guide (26) and the valve seat (18). One advantage of said arrangement is the compact construction of the injection valve (1) and the low dead volume of the control chamber (11) on the reverse side of the injector needle.

Abstract: The invention concerns an injector for the injection of fuel into the combustion chambers of combustion engines. Inside an injector housing (9) is located a nozzle needle (14), which is surrounded by a nozzle chamber (18). The nozzle needle (14) is moveable back and forth within the injector housing, and is aligned by the guiding sections (16, 22) inside the injector housing (9). A thick spring (11) pressed the nozzle needle against the injector (14) a ring canal (23) is formed between injector housing (9) and nozzle needle (14) and a conical section (33) of said nozzle needle (14) follows in the direction towards the seat (30).

Abstract: In a fuel injection valve for internal combustion engines, having a valve housing, having an axially movable valve member for opening and closing an injection opening of the injection valve, and having a part, which acts in the closing direction of the valve member, which is guided with its end remote from the injection opening in a bore of a first valve piece inserted into the valve housing and with this end, encloses a control pressure chamber in the first valve piece, which control pressure chamber can be connected to a high-pressure fuel connection via an inlet conduit, which is provided with at least one inlet throttle, and can be connected to a low-pressure fuel connection via an outlet conduit, which has an outlet throttle and can be closed by a movable control valve member, where the injection process can be controlled by means of the fuel pressure in the control pressure chamber, the proposal is made that at least the section of the inlet conduit provided with the inlet throttle be disposed in a seco

Abstract: An oil activated fuel injector control valve which reduces bouncing of the spool and an impact of the spool on an open coil. This eliminates shot by shot variations in the fuel injector as well as increasing the efficiency of the fuel injector. The fuel injector includes a valve control body which has a vent holes which prevent air from mixing with the working fluid. In this manner, the working fluid does not have to compress and/or dissolve the air in the working ports prior to acting on the piston and plunger mechanism in an intensifier body of the fuel injector.

Abstract: The present invention relates to a valve for controlling fluids, which includes a valve member (4) that is actuatable via a piezoelectric actuator (2) and a hydraulic booster (3). The valve further includes a holder (6), a valve piece (7), a shim (8), and a nozzle body (9). The valve piece (7), the shim (8), and the nozzle body (9) are joined together via at least two screws (13), and the screws (13) are disposed radially to a center axis (M-M) of the valve. This makes both a simple design of the valve and economical assembly possible.

Abstract: A fuel injection device has an actuator, and a displacement amplification chamber for amplifying the amount of displacement of the actuator. The displacement amplification chamber is connected to a fuel passage via a replenishment fuel passage that has a check valve that allows a fuel to flow only toward the displacement amplification chamber. A throttle portion is formed in the replenishment fuel passage.

Abstract: A variable pressure fuel injection system and multi-flow rate injector is provided which produces multiple fuel injection flow rates from a common source of pressurized fuel to enable reductions in emissions, combustion noise and particulates while improving fuel consumption. The present invention includes inner and outer needle valve elements biased into respective closed positions against respective valve seats for controlling the flow through corresponding sets of injection orifices. The movement of each valve is controlled by an injection control valve controlling the drain flow of control fuel from respective control volumes positioned at outer ends of the valve elements. Valve element bias spring preloads along with control flow orifices and needle valve element surface areas are selected to cause, for example, single valve operation at low fuel supply pressure and dual valve operation at high supply pressure.

Abstract: In a fuel injection valve having a pressure control chamber, a nozzle, and an electromagnetic valve, a fuel flow-in passage, a fuel flow-out passage and at least a part of the pressure control chamber are formed in a single piece of a plate in such a manner that the part of the pressure control chamber is opened to an axial end surface of the plate and the fuel flow-out passage extends so as to penetrate the plate axially from an inner wall of the part of the pressure control chamber to another axial end surface of the plate and the fuel flow-in passage comprises a first passage extending from the axial end surface of the plate and a second passage extending from the inner wall of the part of the pressure control chamber, which intersect with each other within the plate, wherein an entrance orifice is formed in first passage.

Abstract: In an injection nozzle for a fuel injection system, the opening stroke of the nozzle needle is to be limited selectively, so that different injection cross sections can be employed. To that end, the injection nozzle is provided with a nozzle body, a nozzle needle displaceable in the nozzle body, two groups of injection ports, which are uncovered as a function of an opening stroke of the nozzle needle, a piston that is connected to the nozzle needle, a stop chamber in which the piston is disposed and which is provided with an outlet, and a control valve that can open and close the outlet of the stop chamber, as a result of which the stroke of the piston in the stop chamber and thus the opening stroke of the nozzle needle can be selectively limited.

Abstract: A fuel injection valve includes a housing in which a pistonlike valve member is disposed longitudinally displaceably in a bore to cause at least one injection opening to communicate with a pressure chamber embodied in the housing. An inlet conduit discharges into the pressure chamber to fill the pressure chamber with fuel at high pressure. A fuel-filled control chamber in the housing at least indirectly exerts a force acting in the closing direction on the valve member. The control chamber communicates with the inlet conduit and can be made to communicate via a control valve with a leak fuel chamber. A damping chamber communicates with the inlet conduit via a throttle.

Abstract: An injection for injecting fuel under high pressure in a combustion chamber of an internal combustion engine has a control chamber, a valve body which is pressure loaded from the control chamber, a further control chamber, a nozzle needle which is pressure loaded from the further control chamber, a nozzle inlet, a nozzle chamber provided for the nozzle needle and loaded from the nozzle inlet, a valve body formed as a 3/2-way valve for pressure controlling the injector, a 2/2-way valve for stroke controlling of the injector at a leakage oil side, and a common controller, the valves being controllable either by the common controller or separately from one another.

Abstract: When an engine is cold-started, the engine oil is quite viscous and requires larger passageways to flow through the engine than when the engine is warmed up and the engine oil flows readily. The present invention relates to a pin valve assembly which may be used on a fuel injector of an engine. The pin valve assembly of the present invention includes a movable shuttle which allows for a relatively large fluid flow space within the pin valve assembly when the engine is cold, and then moves to reduce the fluid flow space when the engine oil is less viscous and requires less room to flow as desired. Therefore, the advantages of a relatively large fluid flow space as well as a shorter pin travel distance within the pin valve assembly are both preserved.

Abstract: A unitary fuel injector and nozzle assembly comprising a high-pressure piston pump and a cylinder body that define a high-pressure fuel pump chamber. An injector nozzle assembly is in fluid communication with the pump chamber and is held in place by a nozzle nut detachably secured to the cylinder body. A nozzle valve assembly includes a spring located in a spring cage within the nozzle nut. A control module is assembled between the cylinder body and the spring cage, the module including a module body having a valve chamber that receives a control valve and a stator assembly as separate and removable elements of the module whereby the stator assembly, the nozzle valve assembly and the control valve can be changed independently of the other elements of the injector to meet various operating requirements.

Abstract: A dual solenoid latching actuator is disclosed and provides an electrical circuit that includes at least one current restrictor, which are preferably a first diode and a second diode. The at least one current restrictor is positioned and arranged such that current flowing in a first direction can energize only one of a first solenoid coil and a second solenoid coil and current flowing in a second direction can energize only the other solenoid coil.

Abstract: A fuel injection device for an internal combustion engines includes a housing with an injection end. A recess extends inside the housing contains an axially movable valve element, which cooperates with a valve seat and has a pressure surface oriented away from the injection end, which pressure surface axially delimits a control chamber. A device is provided which acts on the valve element counter to the force resultant of the pressure surface. A control valve is connected to the control chamber via a flow throttle. The control valve has at least three connections and at least two switching positions and is connected to a high-pressure fluid inlet and a low-pressure fluid outlet on the one side and be connected to the flow throttle on the other side.

Abstract: A common-rail injection system includes a first accumulator of high pressure and a second accumulator of low pressure. The common-rail injection system includes a post injection control device for injecting additional low-pressure fuel from the second accumulator through a fuel injection nozzle after main fuel is injected. The post injection control device injects the additional fuel the injection terminates at a first timing when the fuel pressure in either fuel passage or second accumulator lowers to a predetermined value lower than that of the high-pressure fuel or at a second timing when an exhaust stroke of the engine is completed, whichever earlier.

Abstract: An improved fuel injector is provided which effectively controls fuel injection events using two injection control valves which operate in series to control the movement of a nozzle valve element. An outer injection control valve and actuator assembly operates to control fluid pressure in a control volume adjacent an inner injection control valve thereby controlling the movement of the inner control valve which, in turn, controls fuel pressure in an inner control volume adjacent one end of the nozzle valve element. A particular design of the inner injection control valve prevents control valve oscillations thereby minimizing unwanted fuel injection variations.

Abstract: The movement of the intensifier piston in a fuel injector, to control the pressurization of fuel, can be controlled with a flow control valve. The flow control valve provides different flow rates depending upon the direction of flow. In a first direction, flow control valve has a first rate of flow and in the second direction flow control valve allows a second different rate of flow. Typically, this can be applied to a intensifier piston as follows: flow traveling to the intensifier piston, in the first direction, has a first flow rate, allowing the intensifier to move downward and pressurize fuel. When injection is over, and the intensifier piston is vented, the flow control valve allows a second flow rate which is greater than the first flow rate, allowing the intensifier piston to vent quickly and reset for another injection.

Abstract: An injector for injecting fuel in a combustion chamber of an internal combustion engine has an injector housing, 2/2-way double valves received in the injector housing and coupled with one another for joint vertical movements, a hydraulic multiplier associated with the 2/2-way-control valves, a nozzle chamber which surrounds a nozzle needle and supplied with high pressure fuel by the hydraulic multiplier, the 2/2-way control valves in the housing being turned relative to one another and have valve bodies and guiding elements which surround the valve bodies.

Abstract: A fuel injector for injecting pressure fuel in a combustion chamber of an internal combustion engine has an injector housing, an inlet connectable with a high pressure collecting chamber, a nozzle inlet line, a 2/2-way valve for opening and closing the nozzle inlet line, a control chamber in which a pressure change occurs, at least one first ball valve positioned at a side of the control chamber, at least one second ball valve positioned at a side of the inlet, and a guide element movable in the housing, the first and second ball valve being positioned opposite to one another and associated with the movable guide element.

Abstract: The invention relates to an injector for injecting fuel into combustion chambers of an internal combustion engine. The injector includes an injector housing, in which a control chamber is embodied that can be subjected to a control volume via an inlet throttle. The control chamber can be pressure-relieved to an actuator-actuatable control element as a result of which a control part is movable vertically in the injector housing. The control part and the nozzle needle are embodied integrally.

Abstract: The movement of the intensifier piston in a fuel injector, to control the pressurization of fuel, can be controlled with a flow control valve. The flow control valve provides different flow rates depending upon the direction of flow. In a first direction, flow control valve has a first rate of flow and in the second direction flow control valve allows a second different rate of flow. Typically, this can be applied to a intensifier piston as follows: flow traveling to the intensifier piston, in the first direction, has a first flow rate, allowing the intensifier to move downward and pressurize fuel. When injection is over, and the intensifier piston is vented, the flow control valve allows a second flow rate which is greater than the first flow rate, allowing the intensifier piston to vent quickly and reset for another injection.

Abstract: An ultrasonic fuel injector for injecting a pressurized liquid fuel into the combustion chamber of an internal combustion engine that uses an overhead cam for actuating the injector, includes an injector body and an injector needle. The injector needle is disposed within the body and includes a magnetostrictive portion disposed in the region of the body defined by a ceramic wall, which is transparent to magnetic fields changing at ultrasonic frequencies. A wire coil is wound around the outside surface of the ceramic wall and connected to a source of electric power that is controlled to oscillate at ultrasonic frequencies during predetermined intervals of operation of the injector. A sensor is configured to signal when the overhead cam is actuating the injector to inject fuel into the combustion chamber of the engine.

Abstract: In a pressure-controlled fuel injection system, a nozzle needle is subjected to pressure in the closing direction by a nozzle spring. A nozzle chamber for opening the nozzle needle is connectable to a pressure reservoir via a pressure line. A hydraulic device is embodied to reinforce the closing performance of the nozzle needle. As a result, a faster closing performance of the nozzle needle is achieved.

Abstract: In some hydraulically actuated fuel injectors, a pressure communication passage extends from a pilot valve to the underside of a spool valve to control movement of the same. For the spool valve to move, a substantial amount of fluid flow past the pilot valve is required due to the relatively large amount of fluid that must be displaced by movement of the spool valve member. However, during cold start, when the oil in the pressure communication passage is relatively viscous, it is difficult to move enough fluid past the relatively small flow area through the pilot valve to allow the spool valve to advance to its upper position. Therefore, the fuel injector of the present invention includes a pressure communication passage that is connected to the underside of the spool valve to be separated from the branch that passes through the pilot valve.

Abstract: An injector for injecting fuel into the combustion chambers of an internal combustion engine in which a movable control part is contained in the housing of the injector and is guided in this injector housing to unblock the inlet to an injection nozzle when a closing element relieves the pressure in a control chamber or closes the inlet when a pressure is built up in the control chamber. The nozzle needle of the injector is associated with a piston element which encourages the closing movement of the nozzle needle and counteracts its opening movement.

Abstract: An oil activated fuel injector control valve which substantially eliminates captured air within working fluid of the fuel injector. This eliminates shot by shot variations in the fuel injector as well as increasing the efficiency of the fuel injector. The fuel injector includes a control valve body which has vent holes which prevent air from mixing with the working fluid. In this manner, the working fluid does not have to compress and/or dissolve the air in the working ports prior to acting on the piston and plunger mechanism in an intensifier body of the fuel injector.

Abstract: The invention relates to an injector for injecting fuel into combustion chambers of an internal combustion engine. A control part is provided in the housing of the injector and protrudes into a control chamber, in which a control volume is enclosed. The control chamber can be pressure-relieved via an actuator. In the housing of the injector body, the control part is acted upon by spring elements. The control part is guided in a guide sleeve that defines the control chamber.

Abstract: The invention relates to a common rail fuel injector having an injector housing with a fuel inlet in communication with a central high-pressure fuel reservoir outside the injector housing and with a pressure chamber inside the injector housing. A control valve that assures that a nozzle needle lifts from a seat when the pressure in the pressure chamber is greater than the pressure in a control chamber that communicates with the fuel inlet via an inlet throttle and with a relief chamber via a fuel outlet. The control chamber is integrated with the end, remote from the combustion chamber, of the nozzle needle.

Abstract: The present invention relates to an injection device having an injection valve (12), a valve device (18, 20) for controlling the injection, and a setting element (22) for operating the valve device (18, 20), the valve device having at least one first valve (18) and a second valve (20) which can be operated by the settling element (22) via a common hydraulic coupling space (24). The present invention further relates to a method for injecting fluid in which a setting element is (22) is activated, a valve device (18, 20) is operated by the setting element (22), and an injection valve (12) is opened, the first valve (18) and a second valve (20) of the valve device (18, 20) being operated by the setting element (22) via a common hydraulic coupling space.

Abstract: The invention relates to an injector with a valve chamber which is contained in an injector housing and can be loaded by way of an inlet from the high-pressure accumulation chamber. This valve chamber loads a nozzle inlet to an injection nozzle by means of a control element that can be moved in the injector housing upon the pressure relief of a control chamber. On the control element, which is embodied of one part or multiple parts, a control surface is disposed in the pressure relief region of the nozzle inlet.

Abstract: The invention relates to an injector for injecting fuel into the combustion chambers of an internal combustion engine. The inlet originating at a high-pressure collection chamber (common rail) discharges into the housing of the injector, in which a control part is received, movable vertically. The motion of the control part is effected via the pressure relief of a control chamber, provided in the housing of the injector, by means of an actuator-actuatable closing element. Upon triggering of the control part via the actuator-actuatable closing element, a seat valve embodied as a spherical control body closes or opens inlets and outlets.

Abstract: Disclosed in an injector for injecting fuel into the combustion chambers of an internal combustion engine, in which control part body is received movably in an injector housing and its opening and closing motion is effected via pressure relief of a control chamber. The pressure relief of the control chamber is controlled via an externally actuatable actuator. On the control part body, a sealing seat diameter that seals off the valve chamber is provided, which closes and opens the inlet from a common rail. An annular throttle element of variable cross section is located downstream of the sealing seat diameter of the control part body. An annular throttle element of variable cross section, or a throttle slide with a throttle, is located downstream of the sealing seat diameter of the control part body.

Abstract: In a fuel injection nozzle for an internal combustion engine, having a nozzle body (10), a nozzle needle (12) which is displaceable in the nozzle body between a closed position, in which it rests on a sealing seat (16), and an opened position in which it is lifted from the sealing seat in the direction toward the combustion chamber, having a pressure chamber (24), which communicates with a fuel inlet (26), having a control chamber (42), which under the control of a control valve (46) communicates with the fuel inlet, and having a thrust rod (40), which communicates with the nozzle needle and protrudes into the control chamber, the object is to reliably furnish a closing force that overcomes an opening force generated in the region of the sealing seat.

Abstract: A fuel injector having a fuel flow rate set by injector stroke is disclosed. The fuel injector includes a housing having a hollow passage and a seat disposed at one end of the hollow passage. A needle is slidably mounted in the hollow passage. The needle is operable between a first position wherein the needle engages the seat and a second position wherein the needle is disposed away from the seat. A first flow area is formed by a minimum frusto-conical area between the seat and the needle when the needle is disposed away from the seat. The fuel injector also includes an opening at the one end of the hollow passage proximate to the seat. The opening has a second flow area larger than the first flow area. A method for setting a gaseous fuel injector flow rate with injector stroke is also disclosed.

Abstract: A pressure-controlled injector for injection systems for injecting fuel that is at high pressure into combustion chambers of internal combustion engines. A 3/2-way valve body is provided, which communicates with an inlet for fuel from a high-pressure collection chamber (common rail). The nozzle chamber of a nozzle needle can also be acted upon by fuel at high pressure. The stroke motion of the nozzle needle can be achieved via a hydraulic control chamber that can be pressure-relieved via a control line that has an externally actuatable control element.

Abstract: An electronically-controlled fuel injector includes a pressurized fluid chamber that communicates high pressure fluid to first and second pressure control chambers. A direct-operated check moves between closed and open positions in response to a difference in fluid pressure in the first and second pressure control chambers. A thermally pre-stressed bender actuator is used to operate a control valve that controls the fluid pressure in the first pressure control chamber to effectively control opening and closing of the check during portions of an injection sequence.

Abstract: The invention relates to a fuel injector which includes a hydraulic booster which can be made to communicate on the high-pressure side with an inlet from a high-pressure source. Between a high-pressure side and a system pressure side, there is a throttle restriction. A throttle element that can be acted upon by pressure from the high-pressure side and that is associated with an outflow opening is received movably in a hollow chamber of the injector body and closes a sealing gap that lengthens a sealing length.

Abstract: The fuel injection valve (16) has an injection valve member (24), by which at least one injection opening (26) is controlled. The motion of the injection valve member (24) is influenced by a control valve (18), which has a control valve member (62) by which the pressure in a control pressure chamber (48) is controlled and which is movable by an adjusting force generated by a piezoelectric actuator (80) and in the process control the communication of the control pressure chamber (48) with a relief chamber (12). The control valve (18) has two valve seats (60, 74), spaced apart from one another in the direction of motion of the control valve member (62), with which seats the control valve member (62) cooperates, each with a respective sealing face (66, 69) disposed on it, so that the control valve member (62) has two closing positions, in which the control pressure chamber (48) is disconnected from the relief chamber (12).

Abstract: A common rail injector is proposed which offers great freedom in designing the course of the preinjection main injection and of the injection pressure. Moreover, it offers improved security against leaks into the combustion chamber, caused for instance by a leaking nozzle needle valve seat.

Abstract: The invention relates to an injector for injecting fuel into the combustion chambers of an internal combustion engine. An injector body (3) is provided, which is movable in a housing (2) and whose vertical stroke motion relative to the housing (2) is effected by means of a control chamber (6) that can be pressure relieved via an actuator (10). Via the vertical stroke motion of the injector body (3), the closure or opening of a nozzle inlet line (21) to the injection nozzle (5) takes place. On the injector body, for stroke and/or pressure control of the injector (1), a first slide (23) and a second slide (25) are embodied, offset from one another.

Abstract: An improved closed nozzle injector assembly for injecting high pressure fuel into the combustion chamber of an engine is provided which includes a first needle valve element associated with a first set of injector orifices, a first needle valve control device for controlling the opening and closing of the first needle valve, a second needle valve associated with a second set of injector orifices and a second needle valve control device for controlling the opening and closing of the second needle valve. Each needle valve control device includes a control volume positioned at one end of the respective needle valve, a control volume charge circuit for supplying high pressure fuel to the respective control volume and the respective injection control valve for controlling the flow of high pressure fuel from the respective control volume to a low pressure drain thereby controlling the movement of the respective needle valve.

Abstract: A closed needle injector assembly and method are provided which effectively extending injection duration and improving fueling accuracy at part load conditions, providing a low quantity detached pilot injection at all operating conditions and controlling the duration of, and dwell time between, the pilot injection and one or more higher flow rate primary injections independent of fuel injection pressure. The closed needle injector assembly includes first and second needle valve elements, respective control volumes and a single injection control valve to control the movement of the needle valve elements. A sequencing device is mounted on the injector to permit movement of only the inner needle valve element to define a low fuel injection rate event and permit selectively, controlled movement of both the inner and outer needle valve elements to open positions to define a subsequent primary fuel injection event.

Abstract: A nozzle supply valve is positioned in the nozzle supply passage of a fuel injector, and is constructed to generate a boot shaped rate trace mechanically. The goal of the concept is to restrict the flow area during the first boot step and release the flow area restriction in the second step. During the first stage of injection, the flow to the nozzle only goes through a restricted orifice. When the line pressure is high enough to overcome the valve movement pressure spring preload, the nozzle supply valve moves to an unrestricted position, and the boot shaped rate trace is formed. Since this boot shape rate trace is generated mechanically, it can be combined with fuel injectors having a direct control needle valve in order to get different rate traces including, ramps, squares, pilots, posts and other split injections.

Abstract: An injection nozzle of a pressure-controlled fuel injection system has a control chamber for exerting pressure on a nozzle needle. The control chamber is connectable to a pressure reservoir via a pressure line that includes a 2/2-way valve. On the end of the nozzle needle that can be acted upon by pressure and is remote from the injection opening, a bore is embodied, by way of which the control chamber of the injection nozzle can be made to communicate with a leakage line as a function of the stroke of nozzle needle.

Abstract: In some hydraulically actuated fuel injectors, a pressure communication passage extends from a pilot valve to the underside of a spool valve to control movement of the same. For the spool valve to move, a substantial amount of fluid flow past the pilot valve is required due to the relatively large amount of fluid that must be displaced by movement of the spool valve member. However, during cold start, when the oil in the pressure communication passage is relatively viscous, it is difficult to move enough fluid past the relatively small flow area through the pilot valve to allow the spool valve to advance to its upper position. Therefore, the fuel injector of the present invention includes a pressure communication passage that is connected to the underside of the spool valve to be separated from the branch that passes through the pilot valve.

Abstract: An ultrasonic fuel injector for injecting a pressurized liquid fuel into the combustion chamber of an internal combustion engine that uses an overhead cam for actuating the injector includes a valve body having an injector needle disposed therein forming a needle valve to meter the flow of fuel through the injector. The valve body is formed of ceramic material that is transparent to magnetic fields changing at ultrasonic frequencies. The injector needle includes a magnetostrictive portion disposed in the region of the valve body that is surrounded by a wire coil wound around the outside surface of the ceramic valve body. The wire coil is connected to a source of electric power that oscillates at ultrasonic frequencies. A sensor is configured to signal when the overhead cam is actuating the injector to inject fuel into the combustion chamber of the engine.

Abstract: The control space of the fuel injection valve is delimited, on the one hand, by the piston of the injection-valve member, on the other hand by the slide-valve body and circumferentially by the sleeve. Both the double-acting piston and the slide-valve body are guided in a narrow sliding fit on the sleeve. The throttle passage runs through the slide-valve body and is flow-connected permanently to the control passage in the control body. The throttle inlet leads from the high-pressure space into the control passage. The latter, on the side facing away from the slide-valve body, can, via a pilot valve, be connected to a low-pressure space and be separated again from the latter. The connection of the control passage to the low-pressure space leads to a pressure drop in the control space, with the result being that the injection-valve member moves in the direction of the slide-valve body and releases the injection nozzles.

Abstract: An injector for a common rail fuel injection system in which the opening of the nozzle needle is done under pressure control, while the nozzle needle is compulsorily closed when the control valve closes. This has advantages with regard to the onset of injection and the closing of the nozzle needle.

Abstract: The injector has an injector body having a seat for a metering valve in turn having a control chamber for controlling a control rod. The control chamber has an inlet conduit and a drain conduit controlled by a shutter, and is defined by two parts, one of which is defined by a bush having a through opening for guiding the control rod, and the other of which is defined by a plug member for closing the control chamber. The inlet conduit is located on the bush, and the drain conduit on the plug member. The bush is of such a diameter as to interfere slightly with at least one cylindrical portion of the seat, and is driven in fluidtight manner inside the seat so that an end edge rests on a shoulder of the seat. The plug member is fixed in fluidtight manner to the opposite end of the bush by means of a ring nut having a projection which acts along the centerline of the thickness of the bush.