EP1651861B1 - Control valve with pressure compensation for a fuel injector comprising a pressure intensifier - Google Patents

Control valve with pressure compensation for a fuel injector comprising a pressure intensifier Download PDF

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Publication number
EP1651861B1
EP1651861B1 EP04738705A EP04738705A EP1651861B1 EP 1651861 B1 EP1651861 B1 EP 1651861B1 EP 04738705 A EP04738705 A EP 04738705A EP 04738705 A EP04738705 A EP 04738705A EP 1651861 B1 EP1651861 B1 EP 1651861B1
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EP
European Patent Office
Prior art keywords
pressure
valve
pressure chamber
chamber
valve needle
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
EP04738705A
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German (de)
French (fr)
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EP1651861A1 (en
Inventor
Hans-Christoph Magel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
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Robert Bosch GmbH
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Publication of EP1651861A1 publication Critical patent/EP1651861A1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M57/00—Fuel-injectors combined or associated with other devices
    • F02M57/02—Injectors structurally combined with fuel-injection pumps
    • F02M57/022—Injectors structurally combined with fuel-injection pumps characterised by the pump drive
    • F02M57/025—Injectors structurally combined with fuel-injection pumps characterised by the pump drive hydraulic, e.g. with pressure amplification
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/20—Varying fuel delivery in quantity or timing
    • F02M59/36—Varying fuel delivery in quantity or timing by variably-timed valves controlling fuel passages to pumping elements or overflow passages
    • F02M59/366—Valves being actuated electrically
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/0014—Valves characterised by the valve actuating means
    • F02M63/0015—Valves characterised by the valve actuating means electrical, e.g. using solenoid
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/0031—Valves characterized by the type of valves, e.g. special valve member details, valve seat details, valve housing details
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/0031—Valves characterized by the type of valves, e.g. special valve member details, valve seat details, valve housing details
    • F02M63/0045—Three-way valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/007—Details not provided for in, or of interest apart from, the apparatus of the groups F02M63/0014 - F02M63/0059
    • F02M63/0073—Pressure balanced valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/007—Details not provided for in, or of interest apart from, the apparatus of the groups F02M63/0014 - F02M63/0059
    • F02M63/0078—Valve member details, e.g. special shape, hollow or fuel passages in the valve member

Definitions

  • stroke-controlled injection systems with high-pressure reservoir (common rail) are used.
  • high-pressure reservoir common rail
  • the advantage of these injection systems is that the injection pressure in the combustion chamber can be adapted to the load and speed of the internal combustion engine in a wide range.
  • high injection pressure is required.
  • the achievable pressure level of high-pressure fuel pumps is limited for reasons of strength, so that pressure amplifiers in the fuel injectors are used to further increase the pressure in fuel injection systems.
  • the DE 101 23 917 A has the subject of a fuel injection device for internal combustion engines with a fuel injector which can be supplied by a high-pressure fuel source. Between the fuel injector and the high-pressure fuel source is connected to a movable pressure booster piston having pressure-transmitting device.
  • the pressure booster piston separates a connectable to the high-pressure fuel source space from a high-pressure chamber connected to the fuel injector. By filling a rear space of the pressure booster device with fuel or by emptying the rear space of fuel, the fuel pressure in the high-pressure chamber can be varied.
  • the fuel injector has a movable closing piston for opening and closing injection openings.
  • the closing piston protrudes into a closing pressure chamber, so that the closing piston can be acted upon by fuel pressure in order to achieve a force acting on the closing piston in the closing direction.
  • the closing pressure chamber and the rear space are formed by a common closing pressure-back space, wherein all portions of the closing pressure-return space permanently to exchange fuel with each other are connected.
  • a high-pressure chamber is so in communication with the high-pressure fuel source, that in the high-pressure chamber, apart from pressure oscillations, constantly at least the fuel pressure of the high-pressure fuel source may be present, the pressure chamber and the high-pressure chamber by a common injection space are formed. All sections of the injection space are permanently connected to each other for the exchange of fuel.
  • Another fuel injection device with an injection valve member, a pressure booster device and a switching valve designed as a 3/2-way valve for controlling the injection valve member and the pressure booster device is off DE 102 18 635 A1 known.
  • the pressure booster device has a pressure booster piston, which is exposed to a working space, a differential pressure chamber and a high-pressure chamber.
  • the injection valve member is in communication with a closing space.
  • By means of the 3/2-way valve is a pressure relief and pressurization of the differential pressure chamber. To achieve a closing force for the injection valve member of the working space of the pressure booster device and the closing space of the injection valve member are permanently hydraulically coupled together.
  • a switching valve with four connections and three switching positions for controlling a pressure-controlled fuel injector is off DE 100 31574 A1
  • the valve needle of the control valve comprises three control edges, wherein by means of two control edges a nozzle needle of the injection valve member via the connection with a high-pressure connection aufbwz. is taxable.
  • the further control edge belongs to a slide system, which connects the nozzle needle with a leak relief system for pressure relief.
  • DE 102 294 15.1 refers to a device for Nadelhubdämpfung pressure-controlled fuel injectors.
  • a device for injecting fuel into a combustion chamber of an internal combustion engine which comprises a fuel injector which can be acted upon by a high-pressure source with high-pressure fuel.
  • the fuel injector is actuated via a metering valve, wherein an injection valve member is enclosed by a pressure chamber and the injection valve member in the closing direction by a closing force can be acted upon.
  • the injection valve member is associated with a independently movable damping element, which defines a damping chamber and at least one overflow channel for connecting the damping chamber with a further hydraulic space.
  • the control of the fuel injector with a 3/2-way valve which can indeed represent a cost-effective and space-saving injector, but this valve has to control a relatively large amount of return of the push translator.
  • a direct switching designed as a 3/2-way valve switching valve is proposed, which is completely pressure balanced.
  • a sealing seat and a slide seal is formed at the valve needle of the switching valve.
  • a first first pressure chamber and a second pressure chamber formed at the switching valve.
  • an extension may be formed on the valve needle at the end facing the low-pressure space.
  • the sealing seat which is located above the low-pressure chamber, can be designed either as a flat seat or as a conical seat.
  • the actuator which actuates the directly switching switching valve can be designed both as a piezoelectric actuator and as a magnetic actuator.
  • a Nadelhubdämpfung be provided, with which the movement of the injection valve member can be limited in the smallest ways.
  • the inventive designed as a 3/2-way valve switching valve fuel injectors containing a pressure booster can be operated to control the large return quantities.
  • the solution according to the invention over than 3/2-servo valves trained switching valves have the advantage that they are much easier and thus cheaper to manufacture in terms of manufacturing effort, since only a one-piece valve needle is necessary and the hydraulic control room with the tolerance critical chokes and the necessary pilot valve is eliminated.
  • the formation in a one-piece valve housing ensures a lower number of parts and a high manufacturing accuracy between the needle guide and needle seat.
  • the valve housing can be advantageously formed in two parts, in conjunction with a sealing seat designed as a flat seat. In this case, the sealing seat of the flat seat lies in a second body part designed as a sealing plate. Due to the improved accessibility for processing of the sealing seat, slide edges and valve chambers, a much more cost-effective production of the valve can be achieved.
  • the representation according to Fig. 1 is to take a fuel injector with pressure booster, which is controllable via a differential pressure chamber and can be actuated by means of a direct-switching 3/2-way valve.
  • a pressure source 1 which may be, for example, a high-pressure accumulator (common rail) of a fuel injection system, is connected via a high pressure supply line to a pressure booster 3 in connection.
  • the high-pressure feed line 2 opens into a working space 4 of the pressure booster 3.
  • the working space 4 is separated from a pressure-relieving and pressurizable differential pressure chamber 6 via a booster piston 5.
  • An end face of the booster piston 5 acts on a compression chamber 8 of the pressure booster 3.
  • the booster piston 5 of the booster 3 is associated with a return spring 7, which supports the return movement of the booster piston 5 in its rest position. From the working space 4 of the pressure booster 3, an overflow line 9 extends to a switching valve 22nd
  • the differential pressure chamber 6 of the pressure booster 3 is also connected via a control line 10 to the switching valve 22, which can be actuated via an actuator 37.
  • the actuator 37 can, as in Fig. 1 indicated as a solenoid 38 comprehensive solenoid valve be designed or executed as a piezoelectric actuator.
  • a pressure chamber inlet 11 extends to a pressure chamber 12 which is formed in the body of a fuel injector.
  • an injection valve member 13 is received in the body of the fuel injector.
  • the injection valve member 13 has a pressure stage 14 in the region of the pressure chamber 12.
  • the injection valve member 13 is acted upon at its upper end side via a closing spring 15 accommodated in a control chamber in the closing direction.
  • Fuel injection ports 17 flows from the pressure chamber 12 from an annular gap 16, via which upon pressurization of the pressure chamber 12th Fuel injection ports 17 flows.
  • the injection openings 17 open into a combustion chamber 18 of a self-igniting internal combustion engine.
  • the control line 10 leading from the differential pressure chamber 6 to the switching valve 22 opens into a second pressure chamber 29 in the valve housing 35 of the switching valve 22.
  • the switching valve 22 comprises a valve needle 23.
  • the valve needle 23 has a diameter 27 in its guide region within the integrally formed valve housing 35, the a diameter 26 corresponds to a sealing seat 24 on the valve needle 23.
  • the integrally formed valve needle 23 of the switching valve 22 designed as a direct-switching 3/2 way valve is pressure balanced.
  • the one-piece valve needle 23 of the switching valve 22 has a slide seal 25.
  • the opening into the first pressure chamber 28 of the switching valve 22 from the working chamber 4 from overflow 9 can be closed against the second pressure chamber 29.
  • the sealing seat 24 is closed, the second pressure chamber 29 is closed against a low-pressure space 30.
  • From the low pressure chamber 30 branches off a low-pressure side return 32.2, which leads to a in Fig. 1 Not shown fuel supplies leads.
  • the slide seal 25 of the integrally formed valve needle 23 is formed by a housing side formed control edge 33 and a valve needle side formed control edge 34 and is the sealing seat 24 at the low pressure end of the integrally formed valve needle 23 opposite.
  • valve needle 23 is integrally formed and embedded in a likewise integrally formed valve housing 35.
  • the valve needle 23 is acted upon by a closing spring 36 in the closing direction, so that the sealing seat 24 always closes the second pressure chamber 29 to the low-pressure side return 32.2 when the actuator 37 is not actuated.
  • the sealing seat 24 may be formed as a sealing edge or as a sealing surface.
  • the actuator 37 is formed as a magnetic actuator, containing a coil 38.
  • the lower annular surface of the coil 38 of the magnetic actuator opposite, the integrally formed valve needle 23 has a plate 39.
  • the switching valve 22 is due to acting on the valve needle 23 closing spring 36 in a closed position.
  • the integrally formed valve needle 23 is the differential pressure chamber 6 via the open slide seal 25 of the switching valve 22 and the control line 10, the overflow 9 with the working space 4 in connection.
  • the sealing seat 24 is closed to the low-pressure chamber 30, so that the differential pressure chamber 6 is disconnected from the low-pressure side return and the pressure booster 3 is in is in its pressure balanced state and no pressure boost occurs.
  • the differential pressure chamber 6 is depressurized. This is done by a drive, i. an opening of the switching valve 22, which can be done for example by energizing the solenoid 38, so that the plate 39 is pulled at the top of the valve needle 23 in the direction of the coil 38. Due to this, the valve needle 23 moves upward. In this case, a covering of the control edges 33, 34 of the slide seal 25, so that it closes, whereas the sealing seat 24 opens at the low pressure end of the integrally formed valve needle 23. This results in a decoupling of the differential pressure chamber 6 from the working space 4, d. H.
  • the pressure source 1 and the differential pressure chamber 6 is depressurized via the control line 10, which opens into the second pressure chamber 29, the open sealing seat 24 in the low-pressure side return 32.2.
  • the booster piston 5 of the pressure booster 3 moves into the compression space 8, so that under extremely high pressure fuel passes from these via the pressure space supply line 11 into the pressure chamber 12.
  • the building up in the pressure chamber 12 hydraulic force engages the hydraulically active surface of the pressure stage 14 and moves the injection valve member 13 against the action of the closing spring 15 in an open position, so that from the pressure chamber 12 through the annular gap 16 the injection ports 17 incoming fuel into the combustion chamber 18 of the internal combustion engine can be injected.
  • the pressure balance of the switching valve 22 designed as a direct-switching 3/2-way valve is determined by matching diameter 26 in the region of the sealing seat 24 and in the region of the valve needle 23, cf. Needle diameter 27 achieved in the one-piece housing 35. As a result, both the fuel pressure present in the first pressure chamber 28 and the fuel pressure present in the second pressure chamber 29 exert no forces on the integrally formed valve needle 23.
  • this spring can also be housed in another room of the booster 3, or it can be generated by hydraulic means, a restoring force.
  • the sealing seat 24 may, for example, as a flat seat or as in Fig. 1 be indicated as a conical seat.
  • a two-part valve housing In connection with a two-part valve housing significant manufacturing advantages can be achieved in training the sealing seat 24 as a flat seat.
  • the sealing seat 24 designed as a flat seat can lie in a second valve housing part designed as a sealing plate 35.2 ( FIG. 3 ). Due to the improved accessibility for processing of the sealing seat 24 and the slide edges and valve chambers can be achieved when using a two-piece valve housing a more cost-effective production of the valve.
  • the actuator 37 as a solenoid 38
  • a piezoelectric actuator for actuating the one-piece valve needle 23 of the direct-switching 3/2-way valve 22 can be used.
  • the injection valve 13 can be assigned a damping piston, which controls the opening speed of the injection valve member 13 when the pressure amplifier 3 and its compression space are activated 8 in the pressure chamber 12 incoming, under increased pressure fuel dampens.
  • Fig. 2 shows a further embodiment of a direct-switching 3/2-way valve, the valve needle has a low-pressure side extension.
  • a second low-pressure side return 32.2 branches off.
  • Analogous to the representation of the one-piece valve needle 23 according to Fig. 1 includes the valve needle 23 according to the embodiment according to Fig. 2 a slide seal 25, which is formed by a valve needle-side control edge 34 and a valve housing-side control edge 33.
  • the guide diameter 27 of the valve needle 23 and the seat diameter 26 of the sealing seat 24 correspond to each other.
  • FIG. 2 illustrated embodiment can be achieved that occurring in the low pressure chamber 30 pressure forces do not act on the valve needle 23.
  • the operation of the embodiment, which in Fig. 2 is shown, corresponds to the operation of the in Fig. 1 shown fuel injector with pressure booster 3, which is actuated via the direct-switching switching valve 22, the valve needle 23 without the in Fig. 2 illustrated extension 31 is provided in the low-pressure chamber 30.
  • the switching valve 22 is a direct-switching 3/2-way Valve formed, and can be made due to the one-piece valve needle 23, be it with or without extension 31, much simpler and manufacturing technology cheaper and ensure the one-piece design of the valve housing 35 formed as a direct switching 3/2-way valve switching valve 22 a sufficient manufacturing accuracy and thus a tolerable tightness in high-pressure injection systems for direct-injection internal combustion engines.
  • a two-part valve housing 35 can be located in a trained as a flat seat sealing seat 24 in a designed as a sealing plate 35.2 valve housing part.
  • This embodiment opens up the possibility of improved accessibility for processing of the sealing seat 24 of the slide seal 25 and the Venteilschn the valve.
  • the variant of a direct switching 3/2-way valve with a multipart valve body is in FIG. 3 shown.
  • the multi-part valve housing 35 includes a first housing part 35.1, in which the valve needle 23 of the direct-switching switching valve 22 is guided. On the valve needle 23, which is formed in a diameter 27, a magnetic coil 38 opposite plate 39 is formed, which in turn is acted upon by the closing spring 36.
  • the housing-side control edge 33 which cooperates with the valve needle-side control edge 34 is formed.
  • the sealing seat 24 is preferably formed as a flat seat. By the sealing seat 24 of the low pressure space 30 is sealed. This can be formed in a particularly simple manner in manufacturing technology as a blind hole, branches off from a second low-pressure side return 32.2.
  • the control line 10 opens into the second pressure chamber 29, which branches off from the working space 4 of the pressure booster 3 overflow 9 opens into the first pressure chamber 28.
  • the second valve body part 35.2 of the multi-part valve housing 35 may be an independent component, which is formed separately from the injector body of a fuel injector. However, the second valve housing part 35.2 designed as a sealing plate can just as well be formed by the injector housing per se.
  • low-pressure side returns 32.1, 32.2 can be merged and connected to a two returns 32.1, 32.2 common return system.
  • the inventively proposed as a direct-switching 3/2-way valve trained switching valve 22 can be used in pressure booster 3, which are controlled by controlling the pressure in the differential pressure chamber 6.
  • pressure booster 3 which are controlled by controlling the pressure in the differential pressure chamber 6.
  • the higher the pressure prevailing there, the higher injection pressure can be achieved at the opening into the combustion chamber 18 of the internal combustion engine injection openings 17.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fuel-Injection Apparatus (AREA)

Abstract

The invention relates to a fuel injector comprising a pressure intensifier (3) that is supplied with high-pressure fuel from a pressure source (1). A working chamber (4) of the pressure intensifier (3) is separated from a differential pressure chamber (6) of the pressure intensifier (3) by means of a pressure relay piston (5). The differential pressure chamber (6) of the pressure intensifier (3) is relieved of pressure and subjected to pressure by means of a control valve (22). Said control valve is connected to the differential pressure chamber (6) by means of a control line (10). A pressure chamber (12) on an injection valve element (13) is connected to a compression chamber (8) of the pressure intensifier (3) by means of a pressure chamber supply line (11). The control valve (22) is embodied as a directly switching 3/2 distributing valve, the valve needle (23, 31) thereof being pressure-compensated and comprising both a sealing seat (24) and a slide seal (25).

Description

Technisches GebietTechnical area

Zum Einbringen von Kraftstoff in die Brennräume direkteinspritzender Verbrennungskraftmaschinen werden hubgesteuerte Einspritzsysteme mit Hochdruckspeicherraum (Common Rail) eingesetzt. Der Vorteil dieser Einspritzsysteme liegt darin, dass der Einspritzdruck in den Brennraum an Last und Drehzahl der Verbrennungskraftmaschine in weiten Bereichen angepasst werden kann. Zur Reduzierung der Emissionen und zum Erzielen einer hohen spezifischen Leistung ist ein hoher Einspritzdruck erforderlich. Das erreichbare Druckniveau von Hochdruckkraftstoffpumpen ist aus Festigkeitsgründen begrenzt, so dass zur weiteren Drucksteigerung bei Kraftstoffeinspritzsystemen Druckverstärker in den Kraftstoffinjektoren zum Einsatz kommen.For introducing fuel into the combustion chambers of direct-injection internal combustion engines, stroke-controlled injection systems with high-pressure reservoir (common rail) are used. The advantage of these injection systems is that the injection pressure in the combustion chamber can be adapted to the load and speed of the internal combustion engine in a wide range. To reduce emissions and achieve high specific power, high injection pressure is required. The achievable pressure level of high-pressure fuel pumps is limited for reasons of strength, so that pressure amplifiers in the fuel injectors are used to further increase the pressure in fuel injection systems.

Stand der TechnikState of the art

Die DE 101 23 917 A hat eine Kraftstoffeinspritzeinrichtung für Brennkraftmaschinen mit einem von einer Kraftstoffhochdruckquelle versorgbaren Kraftstoffinjektor zum Gegenstand. Zwischen dem Kraftstoffinjektor und der Kraftstoffhochdruckquelle ist eine einen beweglichen Druckübersetzerkolben aufweisende Drückübersetzungseinrichtung geschaltet. Der Druckübersetzerkolben trennt einen an die Kraftstoffhochdruckquelle anschließbaren Raum von einem mit dem Kraftstoffinjektor verbundenen Hochdruckraum. Durch Befüllen eines Rückraumes der Druckübersetzungseinrichtung mit Kraftstoff beziehungsweise durch Entleeren des Rückraumes von Kraftstoff kann der Kraftstoffdruck im Hochdruckraum variiert werden. Der Kraftstoffinjektor weist einen beweglichen Schließkolben zum Öffnen und Verschließen von Einspritzöffnungen auf. Der Schließkolben ragt in einen Schließdruckraum hinein, so dass der Schließkolben mit Kraftstoffdruck beaufschlagbar ist zur Erzielung einer in Schließrichtung auf den Schließkolben wirkenden Kraft. Der Schließdruckraum und der Rückraum werden durch einen gemeinsamen Schließdruck-Rückraum gebildet, wobei sämtliche Teilbereiche des Schließdruck-Rückraumes permanent zum Austausch von Kraftstoff miteinander verbunden sind. Es ist ein Druckraum zum Versorgen der Einspritzöffnungen mit Kraftstoff und zum Beaufschlagen des Schließkolbens mit einer in Öffnungsrichtung wirkenden Kraft vorgesehen. Ein Hochdruckraum steht derart mit der Kraftstoffhochdruckquelle in Verbindung, dass im Hochdruckraum, abgesehen von Druckschwingungen, ständig zumindest der Kraftstoffdruck der Kraftstoffhochdruckquelle anliegen kann, wobei der Druckraum und der Hochdruckraum durch einen gemeinsamen Einspritzraum gebildet werden. Sämtliche Teilbereiche des Einspritzraumes sind permanent zum Austausch von Kraftstoff miteinander verbunden.The DE 101 23 917 A has the subject of a fuel injection device for internal combustion engines with a fuel injector which can be supplied by a high-pressure fuel source. Between the fuel injector and the high-pressure fuel source is connected to a movable pressure booster piston having pressure-transmitting device. The pressure booster piston separates a connectable to the high-pressure fuel source space from a high-pressure chamber connected to the fuel injector. By filling a rear space of the pressure booster device with fuel or by emptying the rear space of fuel, the fuel pressure in the high-pressure chamber can be varied. The fuel injector has a movable closing piston for opening and closing injection openings. The closing piston protrudes into a closing pressure chamber, so that the closing piston can be acted upon by fuel pressure in order to achieve a force acting on the closing piston in the closing direction. The closing pressure chamber and the rear space are formed by a common closing pressure-back space, wherein all portions of the closing pressure-return space permanently to exchange fuel with each other are connected. There is provided a pressure space for supplying the injection openings with fuel and for acting on the closing piston with a force acting in the opening direction. A high-pressure chamber is so in communication with the high-pressure fuel source, that in the high-pressure chamber, apart from pressure oscillations, constantly at least the fuel pressure of the high-pressure fuel source may be present, the pressure chamber and the high-pressure chamber by a common injection space are formed. All sections of the injection space are permanently connected to each other for the exchange of fuel.

Eine weitere Kraftstoffeinspritzeinrichtung mit einem Einspritzventilglied, einer Druckübersetzungseinrichtung und einem als 3/2-Wege-Ventil ausgebildeten Schaltventil zur Ansteuerung des Einspritzventilglieds und der Druckübersetzungseinrichtung ist aus DE 102 18 635 A1 bekannt. Die Druckübersetzungseinrichtung weist einen Druckübersetzerkolben auf, der einem Arbeitsraum, einem Differenzdruckraum und einem Hochdruckraum ausgesetzt ist. Das Einspritzventilglied steht mit einem Schließraum in Verbindung. Mittels des 3/2-Wege-Ventils erfolgt eine Druckentlastung und Druckbeaufschlagung des Differenzdruckraums. Zur Erzielung einer Schließkraft für das Einspritzventilglied sind der Arbeitsraum der Druckübersetzungseinrichtung und der Schließraum des Einspritzventilglieds permanent hydraulisch miteinander gekoppelt.Another fuel injection device with an injection valve member, a pressure booster device and a switching valve designed as a 3/2-way valve for controlling the injection valve member and the pressure booster device is off DE 102 18 635 A1 known. The pressure booster device has a pressure booster piston, which is exposed to a working space, a differential pressure chamber and a high-pressure chamber. The injection valve member is in communication with a closing space. By means of the 3/2-way valve is a pressure relief and pressurization of the differential pressure chamber. To achieve a closing force for the injection valve member of the working space of the pressure booster device and the closing space of the injection valve member are permanently hydraulically coupled together.

Ein Schaltventil mit vier Anschlüssen und drei Schaltstellungen zur Ansteuerung eines druckgesteuerten Kraftstoffinjektors ist aus DE 100 31574 A1 bekannt Die Ventilnadel des Steuerventils umfasst drei Steuerkanten, wobei mittels zwei Steuerkanten eine Düsennadel des Einspritzventilglieds über die Verbindung mit einem Hochdruckanschluss auf- bwz. zusteuerbar ist. Die weitere Steuerkante gehört zu einem Schiebersystem, das zur Druckentlastung die Düsennadel mit einem Lecköseystem verbindet.A switching valve with four connections and three switching positions for controlling a pressure-controlled fuel injector is off DE 100 31574 A1 The valve needle of the control valve comprises three control edges, wherein by means of two control edges a nozzle needle of the injection valve member via the connection with a high-pressure connection aufbwz. is taxable. The further control edge belongs to a slide system, which connects the nozzle needle with a leak relief system for pressure relief.

DE 102 294 15.1 bezieht sich auf eine Einrichtung zur Nadelhubdämpfung an druckgesteuerten Kraftstoffinjektoren. Es wird eine Einrichtung zum Einspritzen von Kraftstoff in einen Brennraum einer Verbrennungskraftmaschine offenbart, die einen Kraftstoffinjektor umfasst, der über eine Hochdruckquelle mit unter hohem Druck stehenden Kraftstoff beaufschlagbar ist. Der Kraftstoffinjektor wird über ein Zumessventil betätigt, wobei ein Einspritzventilglied von einem Druckraum umschlossen ist und das Einspritzventilglied in Schließrichtung durch eine Schließkraft beaufschlagbar ist. Dem Einspritzventilglied ist ein von diesem unabhängig bewegbares Dämpfungselement zugeordnet, welches einen Dämpfungsraum begrenzt und mindestens einen Überströmkanal zur Verbindung des Dämpfungsraumes mit einem weiteren hydraulischen Raum aufweist. Gemäß DE 102 294 15.1 erfolgt die Steuerung des Kraftstoffinjektors mit einem 3/2-Ventil, wodurch sich zwar ein kostengünstiger und bauraumsparender Injektor darstellen lässt, jedoch dieses Ventil eine relativ große Rücklaufmenge des Drückübersetzers zu steuern hat. DE 102 294 15.1 refers to a device for Nadelhubdämpfung pressure-controlled fuel injectors. Disclosed is a device for injecting fuel into a combustion chamber of an internal combustion engine, which comprises a fuel injector which can be acted upon by a high-pressure source with high-pressure fuel. The fuel injector is actuated via a metering valve, wherein an injection valve member is enclosed by a pressure chamber and the injection valve member in the closing direction by a closing force can be acted upon. The injection valve member is associated with a independently movable damping element, which defines a damping chamber and at least one overflow channel for connecting the damping chamber with a further hydraulic space. According to DE 102 294 15.1 The control of the fuel injector with a 3/2-way valve, which can indeed represent a cost-effective and space-saving injector, but this valve has to control a relatively large amount of return of the push translator.

Anstelle der aus DE 102 294 15.1 bekannten Ausführungsform eines 3/2-Ventiles können auch Servoventile eingesetzt werden, die im Ruhe zustand des Servoventiles am Führungsabschnitt leckagefrei ausgebildet sind, was den Wirkungsgrad eines Kraftstoffinjektors günstig beeinflusst. Nachteilig ist jedoch der Umstand, dass im geöffneten Zustand des Servoventilkolbens des 3/2-Wegeventils keine in dessen Öffnungsrichtung weisende Druckfläche mit Systemdruck beaufschlagt ist. Dadurch wird die Bewegung des Servoventilkolbens in seinem Gehäuse sehr toleranzempfindlich. Ferner lässt sich eine langsame Öffnungsgeschwindigkeit des Servoventilkolbens nicht erreichen, wodurch die Kleinstmengenfähigkeit eines derart konfigurierten Servoventiles eingeschränkt ist. Im geöffneten Zustand des Servoventilkolbens stellt sich an einem an diesem ausgebildeten zweiten Ventilsitz nur eine ungenügende Schließkraft ein, was zu Undichtigkeiten und zu erhöhtem Verschleiß führen kann.Instead of the DE 102 294 15.1 known embodiment of a 3/2 valve and servo valves can be used, which are formed leak-free state at rest of the servo valve on the guide portion, which affects the efficiency of a fuel injector low. The disadvantage, however, is the fact that in the open state of the servo valve piston of the 3/2-way valve, no pressure surface pointing in its opening direction is subjected to system pressure. This makes the movement of the servo valve piston in its housing very sensitive to tolerances. Furthermore, a slow opening speed of the servo valve piston can not be achieved, whereby the small quantity capability of a servo valve configured in this way is limited. In the opened state of the servo valve piston, only an insufficient closing force arises at a second valve seat formed thereon, which can lead to leaks and to increased wear.

Nachteilig bei den aus dem Stande der Technik bekannten Servoventilen sind einerseits der große fertigungstechnische Aufwand sowie andererseits die damit verbunden Kosten.A disadvantage of the servovalves known from the prior art, on the one hand, the great manufacturing effort and, on the other hand, the associated costs.

Darstellung der ErfindungPresentation of the invention

Mit der erfindungsgemäß vorgeschlagenen Lösung wird ein direktschaltendes, als 3/2-Wegeventil ausgebildetes Schaltventil vorgeschlagen, welches vollständig druckausgeglichen ist. An der Ventilnadel des Schaltventiles ist sowohl ein Dichtsitz als auch eine Schieberdichtung ausgebildet. Am Schaltventil sind, oberhalb eines Niederdruckraumes ein erster erster Druckraum sowie ein zweiter Druckraum ausgebildet. Zur Erzielung einer Druckausgeglichenheit sind der Durchmesser des Dichtsitzes und der Durchmesser der Ventilnadel nahezu identisch, so dass der Kraftstoffdruck aus einem ersten Druckraum und der Kraftstoffdruck aus einem zweiten Druckraum keine Kräfte auf die Ventilnadel äuszuüben vermögen.With the proposed solution according to the invention a direct switching, designed as a 3/2-way valve switching valve is proposed, which is completely pressure balanced. At the valve needle of the switching valve both a sealing seat and a slide seal is formed. At the switching valve, above a low-pressure chamber, a first first pressure chamber and a second pressure chamber formed. To achieve a pressure balance of the diameter of the sealing seat and the diameter of the valve needle are almost identical, so that the fuel pressure from a first pressure chamber and the fuel pressure from a second pressure chamber are able to overexpose forces on the valve needle.

Um zu vermeiden, dass aus dem Niederdruckraum Kräfte auf die Ventilnadel wirken, kann an der Ventilnadel an dem dem Niederdruckraum zuweisenden Ende ein Fortsatz ausgebildet sein.In order to avoid forces acting on the valve needle from the low-pressure space, an extension may be formed on the valve needle at the end facing the low-pressure space.

Der Dichtsitz, der sich oberhalb des Niederdruckraumes befindet, kann entweder als Flachsitz oder als Kegelsitz ausgebildet werden. Der das direktschaltende Schaltventil betätigende Aktor kann sowohl als Piezosteller als auch als Magnetaktor ausgebildet sein. Zur Verbesserung der Zumessgenauigkeit und zur Dosierung kleiner Kraftstoffmengen kann eine Nadelhubdämpfung vorgesehen werden, mit welcher die Bewegung des Einspritzventilgliedes auf kleinste Wege begrenzt werden kann. Durch das erfindungsgemäße, als 3/2-Wegeventil ausgebildete Schaltventil können Kraftstoffinjektoren, die einen Druckverstärker enthalten betätigt werden, um die großen Rücklaufmengen zu beherrschen. Die erfindungsgemäße Lösung bietet gegenüber als 3/2-Servo-Ventilen ausgebildeten Schaltventilen den Vorteil, dass diese hinsichtlich des fertigungstechnischen Aufwandes wesentlich einfacher und damit kostengünstiger zu fertigen sind, da nur eine einteilige Ventilnadel notwendig ist und der hydraulische Steuerraum mit den toleranzkritischen Drosseln und dem notwendigen Vorsteuerventil entfällt. Die Ausbildung in einem einteiligen Ventilgehäuse gewährleistet eine geringere Teilanzahl und eine hohe Fertigungsgenauigkeit zwischen der Nadelführung und Nadelsitz. Andererseits kann das Ventilgehäuse in vorteilhafter Weise auch zweiteilig ausgebildet werden, in Verbindung mit einem als Flachsitz ausgebildeten Dichtsitz. Dabei liegt der Dichtsitz des Flachsitzes in einem zweiten als Dichtplatte ausgebildeten Körperteil. Durch die verbesserte Zugänglichkeit zur Bearbeitung von Dichtsitz, Schieberkanten und Ventilkammern lässt sich eine wesentlich kostengünstigere Fertigung des Ventiles erreichen.The sealing seat, which is located above the low-pressure chamber, can be designed either as a flat seat or as a conical seat. The actuator which actuates the directly switching switching valve can be designed both as a piezoelectric actuator and as a magnetic actuator. To improve the metering accuracy and the dosage of small amounts of fuel, a Nadelhubdämpfung be provided, with which the movement of the injection valve member can be limited in the smallest ways. The inventive, designed as a 3/2-way valve switching valve fuel injectors containing a pressure booster can be operated to control the large return quantities. The solution according to the invention over than 3/2-servo valves trained switching valves have the advantage that they are much easier and thus cheaper to manufacture in terms of manufacturing effort, since only a one-piece valve needle is necessary and the hydraulic control room with the tolerance critical chokes and the necessary pilot valve is eliminated. The formation in a one-piece valve housing ensures a lower number of parts and a high manufacturing accuracy between the needle guide and needle seat. On the other hand, the valve housing can be advantageously formed in two parts, in conjunction with a sealing seat designed as a flat seat. In this case, the sealing seat of the flat seat lies in a second body part designed as a sealing plate. Due to the improved accessibility for processing of the sealing seat, slide edges and valve chambers, a much more cost-effective production of the valve can be achieved.

Zeichnungdrawing

Anhand der Zeichnung wird die Erfindung nachstehend eingehender beschrieben.With reference to the drawing, the invention will be described below in more detail.

Es zeigt:

Figur 1
einen Kraftstoffinjektor mit Druckverstärker, welcher über den Differenzdruck- raum gesteuert wird und über ein direktschaltendes 3/2-Wegeventil geschaltet wird und
Figur 2
eine weitere Ausführungsvariante eines Kraftstoffinjektors, dessen 3/2- Schaltventil eine Ventilnadel aufweist, an welcher im Bereich des Niederdruck- raumes des Schaltventiles ein Fortsatz ausgebildet ist, und
Figur 3
ein mehrteiliges Ventilgehäuse eines direkt schaltenden 3/2-Wegeventils.
It shows:
FIG. 1
a fuel injector with pressure booster, which is controlled via the differential pressure chamber and is connected via a direct-switching 3/2-way valve and
FIG. 2
a further embodiment of a fuel injector whose 3/2-way valve has a valve needle, on which an extension is formed in the region of the low-pressure chamber of the switching valve, and
FIG. 3
a multi-part valve body of a direct-acting 3/2-way valve.

Ausführungsvariantenvariants

Der Darstellung gemäß Fig. 1 ist ein Kraftstoffinjektor mit Druckverstärker zu entnehmen, der über einen Differenzdruckraum steuerbar ist und mittels eines direktschaltenden 3/2-Wege-Ventiles betätigbar ist.The representation according to Fig. 1 is to take a fuel injector with pressure booster, which is controllable via a differential pressure chamber and can be actuated by means of a direct-switching 3/2-way valve.

Über eine Druckquelle 1, bei der es sich zum Beispiel um einen Hochdruckspeicher (Common Rail) eines Kraftstoffeinspritzsystems handeln kann, steht über eine Hochdruckzuleitung mit einem Druckverstärker 3 in Verbindung. Die Hochdruckzuleitung 2 mündet in einen Arbeitsraum 4 des Druckverstärkers 3. Der Arbeitsraum 4 ist von einem druckentlastbaren und druckbeaufschlagbaren Differenzdruckraum 6 über einen Verstärkerkolben 5 getrennt. Eine Stirnseite des Verstärkerkolbens 5 beaufschlagt einen Kompressionsraum 8 des Druckverstärkers 3. Dem Verstärkerkolben 5 des Druckverstärkers 3 ist eine Rückstellfeder 7 zugeordnet, welche die Rückstellbewegung des Verstärkerkolbens 5 in seine Ruhelage unterstützt. Vom Arbeitsraum 4 des Druckverstärkers 3 erstreckt sich eine Überströmleitung 9 zu einem Schaltventil 22.About a pressure source 1, which may be, for example, a high-pressure accumulator (common rail) of a fuel injection system, is connected via a high pressure supply line to a pressure booster 3 in connection. The high-pressure feed line 2 opens into a working space 4 of the pressure booster 3. The working space 4 is separated from a pressure-relieving and pressurizable differential pressure chamber 6 via a booster piston 5. An end face of the booster piston 5 acts on a compression chamber 8 of the pressure booster 3. The booster piston 5 of the booster 3 is associated with a return spring 7, which supports the return movement of the booster piston 5 in its rest position. From the working space 4 of the pressure booster 3, an overflow line 9 extends to a switching valve 22nd

Der Differenzdruckraum 6 des Druckverstärkers 3 ist über eine Steuerleitung 10 ebenfalls mit dem Schaltventil 22 verbunden, welches über einen Aktor 37 betätigbar ist. Der Aktor 37 kann, wie in Fig. 1 angedeutet, als ein eine Magnetspule 38 umfassendes Magnetventil ausgestaltet sein oder auch als Piezoaktor ausgeführt werden.The differential pressure chamber 6 of the pressure booster 3 is also connected via a control line 10 to the switching valve 22, which can be actuated via an actuator 37. The actuator 37 can, as in Fig. 1 indicated as a solenoid 38 comprehensive solenoid valve be designed or executed as a piezoelectric actuator.

Vom Kompressionsraum 8 des Druckverstärkers 3 erstreckt sich eine Druckraumzuleitung 11 zu einem Druckraum 12, der im Körper eines Kraftstoffinjektors ausgebildet ist. Im Körper des Kraftstofinjektors ist ein Einspritzventilglied 13 aufgenommen. Das Einspritzventilglied 13 weist im Bereich des Druckraumes 12 eine Druckstufe 14 auf. Das Einspritzventilglied 13 ist an seiner oberen Stirnseite über eine in einem Steuerraum aufgenommene Schließfeder 15 in Schließrichtung beaufschlagt. Vom Druckraum 12 aus erstreckt sich ein Ringspalt 16, über welchen bei Druckbeaufschlagung des Druckraumes 12 Kraftstoff Einspritzöffnungen 17 zuströmt. Die Einspritzöffnungen 17 münden in einen Brennraum 18 einer selbstzündenden Verbrennungskraftmaschine.From the compression chamber 8 of the pressure booster 3, a pressure chamber inlet 11 extends to a pressure chamber 12 which is formed in the body of a fuel injector. In the body of the fuel injector, an injection valve member 13 is received. The injection valve member 13 has a pressure stage 14 in the region of the pressure chamber 12. The injection valve member 13 is acted upon at its upper end side via a closing spring 15 accommodated in a control chamber in the closing direction. From the pressure chamber 12 from an annular gap 16, via which upon pressurization of the pressure chamber 12th Fuel injection ports 17 flows. The injection openings 17 open into a combustion chamber 18 of a self-igniting internal combustion engine.

Die Druckbeaufschlagung des die Schließfeder 15 aufnehmenden Steuerraumes oberhalb des Einspritzventilgliedes 13 erfolgt über eine den Differenzdruckraum 6 des Druckverstärkers 3 mit dem die Schließfeder aufnehmenden Steuerraum verbindende Verbindungsleitung 19. Von dieser zweigt ein Abzweig 20 ab, in welchem ein Befüllventil 21 aufgenommen ist, welches in den Kompressionsraum 8 des Druckverstärkers 3 mündet und zu dessen Wiederbefüllung bei einer Rückstellbewegung des Übersetzerkolbens 5 dient.The pressurization of the closing spring 15 receiving control chamber above the injection valve member 13 via a differential pressure chamber 6 of the pressure booster 3 with the closing spring receiving control room connecting connecting line 19. From this branches off a branch 20, in which a filling valve 21 is added, which in the Compression space 8 of the pressure booster 3 opens and serves to refill it during a return movement of the booster piston 5.

Die vom Differenzdruckraum 6 zum Schaltventil 22 führende Steuerleitung 10 mündet in einen zweiten Druckraum 29 im Ventilgehäuse 35 des Schaltventiles 22. Das Schaltventil 22 umfasst eine Ventilnadel 23. Die Ventilnadel 23 weist einen Durchmesser 27 in ihrem Führungsbereich innerhalb des einteilig ausgebildeten Ventilgehäuses 35 auf, der einem Durchmesser 26 an einem Dichtsitz 24 an der Ventilnadel 23 entspricht. Dadurch ist die einteilig ausgebildete Ventilnadel 23 des als direktschaltenden 3/2-Wege-Ventils beschaffenen Schaltventiles 22 druckausgeglichen. Darüber hinaus weist die einteilige Ventilnadel 23 des Schaltventiles 22 eine Schieberdichtung 25 auf.The control line 10 leading from the differential pressure chamber 6 to the switching valve 22 opens into a second pressure chamber 29 in the valve housing 35 of the switching valve 22. The switching valve 22 comprises a valve needle 23. The valve needle 23 has a diameter 27 in its guide region within the integrally formed valve housing 35, the a diameter 26 corresponds to a sealing seat 24 on the valve needle 23. As a result, the integrally formed valve needle 23 of the switching valve 22 designed as a direct-switching 3/2 way valve is pressure balanced. In addition, the one-piece valve needle 23 of the switching valve 22 has a slide seal 25.

Mittels der Schieberdichtung 25 an der einteilig ausgebildeten Ventilnadel 23 kann die in den ersten Druckraum 28 des Schaltventiles 22 vom Arbeitsraum 4 aus mündende Überströmleitung 9 gegen den zweiten Druckraum 29 verschlossen werden. Bei geschlossenem Dichtsitz 24 ist der zweite Druckraum 29 gegen einen Niederdruckraum 30 verschlossen. Vom Niederdruckraum 30 zweigt ein niederdruckseitiger Rücklauf 32.2 ab, der zu einem in Fig. 1 nicht dargestellten Kraftstoffreservoire führt.By means of the slide seal 25 on the integrally formed valve needle 23, the opening into the first pressure chamber 28 of the switching valve 22 from the working chamber 4 from overflow 9 can be closed against the second pressure chamber 29. When the sealing seat 24 is closed, the second pressure chamber 29 is closed against a low-pressure space 30. From the low pressure chamber 30 branches off a low-pressure side return 32.2, which leads to a in Fig. 1 Not shown fuel supplies leads.

Die Schieberdichtung 25 der einteilig ausgebildeten Ventilnadel 23 wird durch eine gehäuseseitig ausgebildete Steuerkante 33 und eine ventilnadelseitig ausgebildete Steuerkante 34 gebildet und liegt dem Dichtsitz 24 am niederdruckseitigen Ende der einteilig ausgebildeten Ventilnadel 23 gegenüber.The slide seal 25 of the integrally formed valve needle 23 is formed by a housing side formed control edge 33 and a valve needle side formed control edge 34 and is the sealing seat 24 at the low pressure end of the integrally formed valve needle 23 opposite.

In vorteilhafter Weise ist die Ventilnadel 23 einteilig ausgebildet und in ein ebenfalls einteilig ausgebildetes Ventilgehäuse 35 eingelassen. Die Ventilnadel 23 wird durch eine Schließfeder 36 in Schließrichtung beaufschlagt, so dass der Dichtsitz 24 bei nicht betätigtem Aktor 37 stets den zweiten Druckraum 29 zum niederdruckseitigen Rücklauf 32.2 verschließt. Der Dichtsitz 24 kann als Dichtkante oder als Dichtfläche ausgebildet werden. In der in Fig. 1 dargestellten Ausführungsvariante ist der Aktor 37 als Magnetaktor ausgebildet, eine Spule 38 enthaltend. Der unteren Ringfläche der Spule 38 des Magnetaktors gegenüberliegend, weist die einteilig ausgebildete Ventilnadel 23 eine Platte 39 auf.Advantageously, the valve needle 23 is integrally formed and embedded in a likewise integrally formed valve housing 35. The valve needle 23 is acted upon by a closing spring 36 in the closing direction, so that the sealing seat 24 always closes the second pressure chamber 29 to the low-pressure side return 32.2 when the actuator 37 is not actuated. The sealing seat 24 may be formed as a sealing edge or as a sealing surface. In the in Fig. 1 illustrated embodiment, the actuator 37 is formed as a magnetic actuator, containing a coil 38. The lower annular surface of the coil 38 of the magnetic actuator opposite, the integrally formed valve needle 23 has a plate 39.

Im deaktivierten Ruhezustand des Druckverstärkers 3 befindet sich das Schaltventil 22 aufgrund der auf die Ventilnadel 23 wirkenden Schließfeder 36 in einer geschlossenen Position. In dieser in Fig. 1 dargestellten Position der einteilig ausgebildeten Ventilnadel 23 steht der Differenzdruckraum 6 über die geöffnete Schieberdichtung 25 des Schaltventiles 22 und die Steuerleitung 10, die Überströmleitung 9 mit dem Arbeitsraum 4 in Verbindung. Dadurch herrscht im Differenzdruckraum 6 des Druckverstärkers 3 derselbe Druck wie im Arbeitsraum 4 des Druckverstärkers 3. Demgegenüber ist aufgrund der Schließkraft der Schließfeder 36 der Dichtsitz 24 zum Niederdruckraum 30 geschlossen, so dass der Differenzdruckraum 6 vom niederdruckseitigen Rücklauf abgekoppelt ist und der Druckverstärker 3 sich in seinem druckausgeglichenen Zustand befindet und keine Druckverstärkung auftritt.In the deactivated state of rest of the booster 3, the switching valve 22 is due to acting on the valve needle 23 closing spring 36 in a closed position. In this in Fig. 1 shown position of the integrally formed valve needle 23 is the differential pressure chamber 6 via the open slide seal 25 of the switching valve 22 and the control line 10, the overflow 9 with the working space 4 in connection. In contrast, due to the closing force of the closing spring 36, the sealing seat 24 is closed to the low-pressure chamber 30, so that the differential pressure chamber 6 is disconnected from the low-pressure side return and the pressure booster 3 is in is in its pressure balanced state and no pressure boost occurs.

Zur Aktivierung des Druckverstärkers 3 wird der Differenzdruckraum 6 druckentlastet. Dies erfolgt durch eine Ansteuerung, d.h. ein Öffnen des Schaltventiles 22, welches beispielsweise über eine Bestromung der Magnetspule 38 erfolgen kann, so dass die Platte 39 an der Oberseite der Ventilnadel 23 in Richtung auf die Spule 38 gezogen wird. Aufgrund dessen bewegt sich die Ventilnadel 23 nach oben. Dabei erfolgt ein Überdecken der Steuerkanten 33, 34 der Schieberdichtung 25, so dass diese schließt, wohingegen der Dichtsitz 24 am niederdruckseitigen Ende der einteilig ausgebildeten Ventilnadel 23 öffnet. Dadurch erfolgt eine Abkopplung des Differenzdruckraumes 6 vom Arbeitsraum 4, d. h. der Druckquelle 1 und der Differenzdruckraum 6 wird über die Steuerleitung 10, welche in den zweiten Druckraum 29 mündet, den offen stehenden Dichtsitz 24 in den niederdruckseitigen Rücklauf 32.2 druckentlastet. Dadurch fährt der Verstärkerkolben 5 des Druckverstärkers 3 in den Kompressionsraum 8 ein, so dass unter extrem hohem Druck stehender Kraftstoff von diesen via Druckraumzuleitung 11 in den Druckraum 12 gelangt. Die sich im Druckraum 12 aufbauende hydraulische Kraft greift an der hydraulisch wirksamen Fläche der Druckstufe 14 an und bewegt das Einspritzventilglied 13 entgegen der Wirkung der Schließfeder 15 in eine Öffnungsstellung, so dass vom Druckraum 12 über den Ringspalt 16 den Einspritzöffnungen 17 zuströmender Kraftstoff in den Brennraum 18 der Verbrennungskraftmaschine eingespritzt werden kann.To activate the pressure booster 3, the differential pressure chamber 6 is depressurized. This is done by a drive, i. an opening of the switching valve 22, which can be done for example by energizing the solenoid 38, so that the plate 39 is pulled at the top of the valve needle 23 in the direction of the coil 38. Due to this, the valve needle 23 moves upward. In this case, a covering of the control edges 33, 34 of the slide seal 25, so that it closes, whereas the sealing seat 24 opens at the low pressure end of the integrally formed valve needle 23. This results in a decoupling of the differential pressure chamber 6 from the working space 4, d. H. the pressure source 1 and the differential pressure chamber 6 is depressurized via the control line 10, which opens into the second pressure chamber 29, the open sealing seat 24 in the low-pressure side return 32.2. As a result, the booster piston 5 of the pressure booster 3 moves into the compression space 8, so that under extremely high pressure fuel passes from these via the pressure space supply line 11 into the pressure chamber 12. The building up in the pressure chamber 12 hydraulic force engages the hydraulically active surface of the pressure stage 14 and moves the injection valve member 13 against the action of the closing spring 15 in an open position, so that from the pressure chamber 12 through the annular gap 16 the injection ports 17 incoming fuel into the combustion chamber 18 of the internal combustion engine can be injected.

Zum Beenden des Einspritzvorganges wird das als direktschaltendes 3/2-Wege-Ventil ausgebildete Schaltventil 22 aktiviert, d.h. geschlossen. Über die Wirkung der Schließfeder 36 bewegt sich die einteilig ausgebildete Ventilnadel 23 in ihre untere Ausgangsstellung. Bei der vertikalen Abwärtsbewegung der einteilig ausgebildeten Ventilnadel 23 erfolgt ein Schließen des Dichtsitzes 24 und ein Öffnen der Schieberdichtung 25, gebildet durch die Steuerkanten 33 bzw. 34. Über den Arbeitsraum 4, die Überströmleitung 9, den ersten Druckraum 28, dem zweiten Druckraum 29 und die Steuerleitung 10 baut sich im Differenzdruckraum 6 des Druckverstärkers 3 Systemdruck auf, wodurch der Druckverstärker 3 deaktiviert wird, d. h. unterstützt durch die Rückstellfeder 7 wieder in seine Ruhelage zurückkehrt. Das Einspritzventilglied 13 schließt, da der Druck im Druckraum 12 bei Druckentlastung des Kompressionsraumes 8 ebenfalls abnimmt.To end the injection process designed as a direct-switching 3/2-way valve switching valve 22 is activated, ie closed. About the action of the closing spring 36, the integrally formed valve needle 23 moves to its lower starting position. In the vertical downward movement of the integrally formed valve needle 23 is a closing of the sealing seat 24 and opening the slide seal 25, formed by the control edges 33 and 34. About the working space 4, the overflow 9, the first pressure chamber 28, the second pressure chamber 29 and the control line 10 builds up in the differential pressure space 6 of the pressure booster 3 system pressure, whereby the pressure booster 3 is deactivated, that is supported by the return spring 7 returns to its rest position. The injection valve member 13 closes, since the pressure in the pressure chamber 12 at pressure relief of the compression chamber 8 also decreases.

Bei Wiederbefüllung des Differenzdruckraumes 6 über die Steuerleitung 10 erfolgt gleichzeitig ein Überströmen von Kraftstoff in die Verbindungsleitung 19 zu dem die Schließfeder 15 aufnehmenden Steuerraum des Einspritzventilgliedes 13. Über den von der Verbindungsleitung 19 abzweigenden Abzweig 20 strömt Kraftstoff über ein Befüllventil 21, welches beispielsweise als Rückschlagventil ausgebildet sein kann, dem wieder zu befüllenden Kompressionsraum 8 des Druckverstärkers 3 zu.When refilling the differential pressure chamber 6 via the control line 10 is simultaneously an overflow of fuel in the connecting line 19 to the closing spring 15 receiving control chamber of the injection valve member 13 via the branching off of the connecting line 19 branch 20 fuel flows through a filling valve 21, which, for example, as a check valve may be formed to the re-to be filled compression chamber 8 of the booster 3 to.

Die Druckausgeglichenheit des als direktschaltendes 3/2-Wege-Ventil ausgebildeten Schaltventiles 22 wird durch übereinstimmende Durchmesser 26 im Bereich des Dichtsitzes 24 und im Bereich der Ventilnadel 23, vgl. Nadeldurchmesser 27 im einteiligen Gehäuse 35 erreicht. Dadurch üben sowohl der im ersten Druckraum 28 anstehende Kraftstoffdruck als auch der im zweiten Druckraum 29 anstehende Kraftstoffdruck keine Kräfte auf die einteilig ausgebildete Ventilnadel 23 aus.The pressure balance of the switching valve 22 designed as a direct-switching 3/2-way valve is determined by matching diameter 26 in the region of the sealing seat 24 and in the region of the valve needle 23, cf. Needle diameter 27 achieved in the one-piece housing 35. As a result, both the fuel pressure present in the first pressure chamber 28 and the fuel pressure present in the second pressure chamber 29 exert no forces on the integrally formed valve needle 23.

Anstelle der im Differenzdruckraum 6 aufgenommenen Rückstellfeder 7 zur Unterstützung der Rückstellbewegung des Verstärkerkolbens 5 in seine Ruhelage, kann diese Stellfeder auch in einem anderen Raum des Druckverstärkers 3 untergebracht sein, oder es kann auf hydraulischem Wege eine Rückstellkraft erzeugt werden.Instead of the resumed in the differential pressure chamber 6 return spring 7 to support the return movement of the booster piston 5 in its rest position, this spring can also be housed in another room of the booster 3, or it can be generated by hydraulic means, a restoring force.

Der Dichtsitz 24 kann zum Beispiel als Flachsitz oder wie in Fig. 1 angedeutet als Kegelsitz ausgebildet werden. In Verbindung mit einem zweiteilig ausgebildeten Ventilgehäuse können bei Ausbildung des Dichtsitzes 24 als Flachsitz erhebliche fertigungstechnische Vorteile erzielt werden. Bei einem zweiteilig ausgebildeten Ventilgehäuse 35, kann der als Flachsitz ausgeführte Dichtsitz 24 in einem zweiten, als Dichtplatte 35.2 ausgebildeten Ventilgehäuseteil liegen (Figur 3). Durch die verbesserte Zugänglichkeit zur Bearbeitung des Dichtsitzes 24 sowie von Schieberkanten und Ventilkammern lässt sich bei Einsatz eines zweiteilig ausgebildeten Ventilgehäuses eine kostengünstigere Fertigung des Ventiles erreichen. Neben der in Fig. 1 dargestellten Ausführungsvariante des Aktors 37 als Magnetspule 38, kann auch ein Piezosteller zur Betätigung der einteiligen Ventilnadel 23 des direktschaltenden 3/2-Wege-Ventiles 22 eingesetzt werden. Zur Verbesserung der Zumessgenauigkeit und zur Darstellung kleiner Einspritzmengen kann dem Einspritzventil 13 ein Dämpfungskolben zugeordnet werden, welcher die Öffnungsgeschwindigkeit des Einspritzventilgliedes 13 bei aktiviertem Druckverstärker 3 und von dessen Kompressionraum 8 in den Druckraum 12 einströmenden, unter erhöhtem Druck stehenden Kraftstoff dämpft.The sealing seat 24 may, for example, as a flat seat or as in Fig. 1 be indicated as a conical seat. In connection with a two-part valve housing significant manufacturing advantages can be achieved in training the sealing seat 24 as a flat seat. In a two-part valve housing 35, the sealing seat 24 designed as a flat seat can lie in a second valve housing part designed as a sealing plate 35.2 ( FIG. 3 ). Due to the improved accessibility for processing of the sealing seat 24 and the slide edges and valve chambers can be achieved when using a two-piece valve housing a more cost-effective production of the valve. In addition to the in Fig. 1 illustrated embodiment of the actuator 37 as a solenoid 38, a piezoelectric actuator for actuating the one-piece valve needle 23 of the direct-switching 3/2-way valve 22 can be used. In order to improve the metering accuracy and to display small injection quantities, the injection valve 13 can be assigned a damping piston, which controls the opening speed of the injection valve member 13 when the pressure amplifier 3 and its compression space are activated 8 in the pressure chamber 12 incoming, under increased pressure fuel dampens.

Fig. 2 ist eine weitere Ausführungsvariante eines direktschaltenden 3/2-Wege-Ventiles zu entnehmen, dessen Ventilnadel einen niederdruckseitigen Fortsatz aufweist. Fig. 2 shows a further embodiment of a direct-switching 3/2-way valve, the valve needle has a low-pressure side extension.

Im Unterschied zur in Fig. 1 dargestellten Ausführungsvariante befindet sich an der Ventilnadel 23 unterhalb des Dichtsitzes 24 ein Fortsatz 31, welcher in den Niederdruckraum 30 eintaucht. Oberhalb des Fortsatzes 31 der einteilig ausgebildeten Ventilnadel 23 verläuft ein erster niederdruckseitiger Rücklauf 32.1, während unterhalb des Fortsatzes 31 ein zweiter niederdruckseitiger Rücklauf 32.2 abzweigt. Analog zur Darstellung der einteiligen Ventilnadel 23 gemäß Fig. 1 umfasst die Ventilnadel 23 gemäß der Ausführungsvariante nach Fig. 2 eine Schieberdichtung 25, welche durch eine ventilnadelseitige Steuerkante 34 und eine ventilgehäuseseitige Steuerkante 33 gebildet wird. Zur Druckausgeglichenheit der Ventilnadel 23 entsprechen der Führungsdurchmesser 27 der Ventilnadel 23 und der Sitzdurchmesser 26 des Dichtsitzes 24 einander. Mit der in Fig. 2 dargestellten Ausführungsvariante kann erreicht werden, dass im Niederdruckraum 30 auftretende Druckkräfte nicht auf die Ventilnadel 23 wirken. Die Funktionsweise der Ausführungsvariante, welche in Fig. 2 dargestellt ist, entspricht der Funktionsweise des in Fig. 1 dargestellten Kraftstoffinjektors mit Druckverstärker 3, der über das direktschaltende Schaltventil 22 betätigt wird, dessen Ventilnadel 23 ohne den in Fig. 2 dargestellten Fortsatz 31 im Niederdruckraum 30 beschaffen ist.Unlike in Fig. 1 illustrated embodiment is located on the valve needle 23 below the sealing seat 24, an extension 31, which dips into the low-pressure chamber 30. Above the extension 31 of the integrally formed valve needle 23 extends a first low-pressure side return 32.1, while below the extension 31, a second low-pressure side return 32.2 branches off. Analogous to the representation of the one-piece valve needle 23 according to Fig. 1 includes the valve needle 23 according to the embodiment according to Fig. 2 a slide seal 25, which is formed by a valve needle-side control edge 34 and a valve housing-side control edge 33. For pressure balance of the valve needle 23, the guide diameter 27 of the valve needle 23 and the seat diameter 26 of the sealing seat 24 correspond to each other. With the in Fig. 2 illustrated embodiment can be achieved that occurring in the low pressure chamber 30 pressure forces do not act on the valve needle 23. The operation of the embodiment, which in Fig. 2 is shown, corresponds to the operation of the in Fig. 1 shown fuel injector with pressure booster 3, which is actuated via the direct-switching switching valve 22, the valve needle 23 without the in Fig. 2 illustrated extension 31 is provided in the low-pressure chamber 30.

Im Vergleich zu den aus dem Stande der Technik bekannten Servoventilen, mit welchen ein Kraftstoffinjektor mit Druckverstärker 3 betätigbar ist, und mit welchen die hohen Absteuermengen bei Druckentlastung des Differenzdruckraumes 6 des Druckverstärkers 3 beherrschbar sind, ist das Schaltventil 22 als direktschaltendes 3/2-Wege-Ventil ausgebildet, und kann aufgrund der einteilig ausgebildeten Ventilnadel 23, sei sie mit oder ohne Fortsatz 31 ausgebildet, wesentlich einfach und fertigungstechnisch günstiger hergestellt werden und die einteilige Ausbildung des Ventilgehäuses 35 des als direktschaltendes 3/2-Wege-Ventils ausgebildeten Schaltventiles 22 gewährleisten eine ausreichende Fertigungsgenauigkeit und damit eine tolerierbare Dichtheit bei Hochdruckeinspritzsystemen für die direkteinspritzende Verbrennungskraftmaschinen.Compared to the known from the prior art servo valves, with which a fuel injector with pressure booster 3 can be actuated, and with which the high Absteuermengen at pressure relief of the differential pressure chamber 6 of the pressure booster 3 are manageable, the switching valve 22 is a direct-switching 3/2-way Valve formed, and can be made due to the one-piece valve needle 23, be it with or without extension 31, much simpler and manufacturing technology cheaper and ensure the one-piece design of the valve housing 35 formed as a direct switching 3/2-way valve switching valve 22 a sufficient manufacturing accuracy and thus a tolerable tightness in high-pressure injection systems for direct-injection internal combustion engines.

Bei einem zweiteilig ausgebildeten Ventilgehäuse 35 kann unter Einsatz eines als Flachsitz ausgebildeten Dichtsitzes 24 dieser in einem als Dichtplatte 35.2 ausgebildeten Ventilgehäuseteil liegen. Diese Ausführungsvariante eröffnet die Möglichkeit einer verbesserten Zugänglichkeit zur Bearbeitung des Dichtsitzes 24 der Schieberdichtung 25 sowie der Venteilkammern des Ventils. Die Ausführungsvariante eines direkt schaltenden 3/2-Wegeventiles mit einem mehrteiligen Ventilgehäuse ist in Figur 3 dargestellt. Das mehrteilige Ventilgehäuse 35 umfasst einen ersten Gehäuseteil 35.1, in welchem die Ventilnadel 23 des direkt schaltenden Schaltventiles 22 geführt ist. An der Ventilnadel 23, die in einem Durchmesser 27 ausgebildet ist, ist eine einer Magnetspule 38 gegenüberliegende Platte 39 ausgebildet, die ihrerseits von der Schließfeder 36 beaufschlagt ist. Im ersten Gehäuseteil 35.1 ist die gehäuseseitige Steuerkante 33, die mit der ventilnadelseitigen Steuerkante 34 zusammenwirkt, ausgebildet. Der Dichtsitz 24 wird bevorzugt als Flachsitz ausgebildet. Durch den Dichtsitz 24 wird der Niederdruckraum 30 abgedichtet. Dieser kann in fertigungstechnisch besonders einfacher Weise als Sacklochbohrung ausgebildet werden, von der ein zweiter niederdruckseitiger Rücklauf 32.2 abzweigt. Die Steuerleitung 10 mündet in den zweiten Druckraum 29, die vom Arbeitsraum 4 des Druckverstärkers 3 abzweigende Überströmleitung 9 mündet in den ersten Druckraum 28. Der zweite Ventilgehäuseteil 35.2 des mehrteiligen Ventilgehäuses 35 kann ein eigenständiges Bauteil darstellen, welches getrennt vom Injektorkörper eines Kraftstoffinjektors ausgebildet ist. Das als Dichtplatte ausgebildete zweite Ventilgehäuseteil 35.2 kann jedoch ebenso gut durch das Injektorgehäuse an sich gebildet werden.In a two-part valve housing 35 can be located in a trained as a flat seat sealing seat 24 in a designed as a sealing plate 35.2 valve housing part. This embodiment opens up the possibility of improved accessibility for processing of the sealing seat 24 of the slide seal 25 and the Venteilkammern the valve. The variant of a direct switching 3/2-way valve with a multipart valve body is in FIG. 3 shown. The multi-part valve housing 35 includes a first housing part 35.1, in which the valve needle 23 of the direct-switching switching valve 22 is guided. On the valve needle 23, which is formed in a diameter 27, a magnetic coil 38 opposite plate 39 is formed, which in turn is acted upon by the closing spring 36. In the first housing part 35.1, the housing-side control edge 33 which cooperates with the valve needle-side control edge 34 is formed. The sealing seat 24 is preferably formed as a flat seat. By the sealing seat 24 of the low pressure space 30 is sealed. This can be formed in a particularly simple manner in manufacturing technology as a blind hole, branches off from a second low-pressure side return 32.2. The control line 10 opens into the second pressure chamber 29, which branches off from the working space 4 of the pressure booster 3 overflow 9 opens into the first pressure chamber 28. The second valve body part 35.2 of the multi-part valve housing 35 may be an independent component, which is formed separately from the injector body of a fuel injector. However, the second valve housing part 35.2 designed as a sealing plate can just as well be formed by the injector housing per se.

Die in der Ausführungsvariante gemäß Figur 2 dargestellten niederdruckseitigen Rückläufe 32.1, 32.2 können zusammengeführt sein und an ein beiden Rückläufen 32.1, 32.2 gemeinsames Rücklaufsystem angeschlossen werden.The in the embodiment according to FIG. 2 illustrated low-pressure side returns 32.1, 32.2 can be merged and connected to a two returns 32.1, 32.2 common return system.

Das erfindungsgemäß vorgeschlagene als direktschaltendes 3/2-Wege-Ventil ausgebildete Schaltventil 22 lässt sich bei Druckverstärkern 3 einsetzen, die über eine Steuerung des Druckes im Differenzdruckraum 6 gesteuert werden. Entsprechend des Auslegungsverhältnisses des Druckverstärkers 3 erfolgt eine Druckerhöhung in dessen Kompressionsraum 8, welcher über die Druckraumzuleitung 11 im Druckraum 12 indem das Einspritzventilglied 13 im Bereich einer Druckstufe 14 umgebenden Druckraum 12 ansteht. Je höher der dort herrschende Druck ist, desto höherer Einspritzdruck lässt sich an den in den Brennraum 18 der Verbrennungskraftmaschine mündenden Einspritzöffnungen 17 erreichen. Bezugszeichenliste 1 Druckquelle (Common Rail) 33 gehäuseseitige Steuerkante 2 Hochdruckzuleitung 34 ventilnadelseitige Steuerkante 3 Druckverstärker 35 Ventilgehäuse 4 Arbeitsraum 35.1 erstes Gehäuseteill 5 Verstärkerkolben 35.2 zweites Gehäuseteil 6 Differenzdruckraum 36 Schließfeder 3/2-Ventil 7 Rückstellfeder 37 Aktor 8 Kompressionsraum 38 Magnetspule 9 Überströmleitung 39 Platte 10 Steuerleitung 11 Druckraumzuleitung 12 Druckraum 13 Einspritzventilglied 14 Druckstufe 15 Schließfeder 16 Ringspalt 17 Einspritzöffnung 18 Brennraum 19 Verbindungsleitung 20 Abzweig 21 Befüllventil 22 Schaltventil (3/2-Wege-Ventil) 23 Ventilnadel 24 Dichtsitz 25 Schieberdichtung 26 Durchmesser Dichtsitz 27 Führungsdurchmesser 28 erster Druckraum 29 zweiter Druckraum 30 Niederdruckraum 31 Ventilnadelfortsatz 32.1 erster niederdruckseitiger Rücklauf 32.2 zweiter niederdruckseitiger Rücklauf The inventively proposed as a direct-switching 3/2-way valve trained switching valve 22 can be used in pressure booster 3, which are controlled by controlling the pressure in the differential pressure chamber 6. According to the design ratio of the booster 3, there is a pressure increase in the compression chamber 8, which via the pressure chamber inlet 11 in the pressure chamber 12 by the injection valve member 13 in the region of a pressure stage 14 surrounding pressure chamber 12 is present. The higher the pressure prevailing there, the higher injection pressure can be achieved at the opening into the combustion chamber 18 of the internal combustion engine injection openings 17. <U> REFERENCE LIST </ u> 1 Pressure source (common rail) 33 housing-side control edge 2 High pressure supply line 34 Valve needle-side control edge 3 booster 35 valve housing 4 working space 35.1 first housing part 5 intensifier piston 35.2 second housing part 6 Differential pressure chamber 36 Closing spring 3/2 valve 7 Return spring 37 actuator 8th compression chamber 38 solenoid 9 overflow 39 plate 10 control line 11 Pressure chamber inlet 12 pressure chamber 13 Injection valve member 14 pressure stage 15 closing spring 16 annular gap 17 Injection port 18 combustion chamber 19 connecting line 20 junction 21 Filling 22 Switching valve (3/2-way valve) 23 valve needle 24 sealing seat 25 slide seal 26 Diameter sealing seat 27 Guide diameter 28 first pressure chamber 29 second pressure chamber 30 Low-pressure chamber 31 Valve needle extension 32.1 first low-pressure side return 32.2 second low-pressure side return

Claims (8)

  1. Fuel injector having a pressure booster (3) which is supplied with highly pressurized fuel from a pressure source (1) via a high-pressure supply line (2) and whose working chamber (4) is separated from a differential pressure chamber (6) by means of a booster piston (5), with the depressurization and pressurization of the differential pressure chamber (6) taking place via a switching valve (22) having a first pressure chamber (28) and a second pressure chamber (29) which is connected via a control line (10) to the differential pressure chamber (6), and a pressure chamber (12) at the injection valve member (13) is connected via a pressure chamber supply line (11) to a compression chamber (8) of the pressure booster (3), characterized in that the switching valve (22) is a direct-switching 3/2 directional valve whose valve needle (23, 31) is pressure-balanced and has both a sealing seat (24) and also a slide seal (25), in that the valve needle (23) has a guide diameter (27) in the valve housing (35), which guide diameter (27) corresponds substantially to a diameter (26) of the sealing seat (24) of the valve needle (23), in that the second pressure chamber (29) of the switching valve (22) can be separated from a low-pressure chamber (30) by means of the sealing seat (24), and in that an overflow line (9) which is connected to the high-pressure supply line (2) opens out into the first pressure chamber (28) of the switching valve (22), and a control line (10), which pressurizes or depressurizes the differential pressure chamber (6) of the pressure booster (3), opens out into the second pressure chamber (29) of the switching valve (22), with it being possible for the pressure chambers (28, 29) to be separated from or connected to one another via the slide seal (25) corresponding to the stroke movement of the valve needle (23).
  2. Fuel injector according to Claim 1, characterized in that the first pressure chamber (28) and the second pressure chamber (29) can be separated from one another by means of the slide seal (25).
  3. Fuel injector according to Claim 1, characterized in that the switching valve (22) has a single-piece valve needle (23).
  4. Fuel injector according to Claim 1, characterized in that the valve needle (23) comprises a valve needle projection (31) which is surrounded by a low-pressure chamber (30).
  5. Fuel injector according to Claim 1, characterized in that the sealing seat (24) on the low-pressure-chamber-side end of the valve needle (23) is formed as a conical seat or as a flat seat.
  6. Fuel injector according to Claim 3, characterized in that the single-piece valve needle (23) is held in a single-piece valve housing (35).
  7. Fuel injector according to Claim 3, characterized in that the single-piece valve needle (23) is guided in a multi-part valve housing (35).
  8. Fuel injector according to Claim 1, characterized in that the guide diameter (27) of the valve needle (23) corresponds to the diameter of the slide seal (25).
EP04738705A 2003-07-30 2004-06-17 Control valve with pressure compensation for a fuel injector comprising a pressure intensifier Expired - Fee Related EP1651861B1 (en)

Applications Claiming Priority (2)

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DE10334771A DE10334771A1 (en) 2003-07-30 2003-07-30 Pressure-equalizing valve for a fuel injector with pressure booster
PCT/DE2004/001254 WO2005015000A1 (en) 2003-07-30 2004-06-17 Control valve with pressure compensation for a fuel injector comprising a pressure intensifier

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EP1651861A1 EP1651861A1 (en) 2006-05-03
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JP4415962B2 (en) * 2006-03-17 2010-02-17 株式会社デンソー Injector
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EP1651861A1 (en) 2006-05-03
JP4113223B2 (en) 2008-07-09
DE502004011616D1 (en) 2010-10-14
US20060202139A1 (en) 2006-09-14
JP2006514217A (en) 2006-04-27
US7316361B2 (en) 2008-01-08
WO2005015000A1 (en) 2005-02-17
DE10334771A1 (en) 2005-02-24

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