EP2726731B1 - Fuel injector - Google Patents

Fuel injector Download PDF

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Publication number
EP2726731B1
EP2726731B1 EP12723454.0A EP12723454A EP2726731B1 EP 2726731 B1 EP2726731 B1 EP 2726731B1 EP 12723454 A EP12723454 A EP 12723454A EP 2726731 B1 EP2726731 B1 EP 2726731B1
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EP
European Patent Office
Prior art keywords
valve
fuel injector
chamber
bolt
compression spring
Prior art date
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EP12723454.0A
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German (de)
French (fr)
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EP2726731A1 (en
Inventor
Holger Rapp
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Robert Bosch GmbH
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Robert Bosch GmbH
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Publication of EP2726731A1 publication Critical patent/EP2726731A1/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
    • 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
    • F02M63/0033—Lift valves, i.e. having a valve member that moves perpendicularly to the plane of the valve seat
    • F02M63/0035—Poppet valves, i.e. having a mushroom-shaped valve member that moves perpendicularly to the plane of the valve seat
    • 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
    • F02M47/00—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
    • F02M47/02—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure of accumulator-injector type, i.e. having fuel pressure of accumulator tending to open, and fuel pressure in other chamber tending to close, injection valves and having means for periodically releasing that closing pressure
    • F02M47/027—Electrically actuated valves draining the chamber to release the closing pressure
    • 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
    • F02M63/007—Details not provided for in, or of interest apart from, the apparatus of the groups F02M63/0014 - F02M63/0059
    • 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
    • F02M63/0071—Details not provided for in, or of interest apart from, the apparatus of the groups F02M63/0014 - F02M63/0059 characterised by guiding or centering means in valves including the absence of any guiding means, e.g. "flying arrangements"
    • 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
    • F02M63/0075—Stop members in valves, e.g. plates or disks limiting the movement of armature, valve or spring

Definitions

  • the invention relates to a fuel injector according to the preamble of claim 1.
  • Such a fuel injector is from the DE 10 2010 063 540 A1 the applicant known.
  • a pressure spring acting on the valve pin in its closed position in a low pressure region separated from the valve chamber is arranged, wherein the low pressure region is hydraulically separated from the valve chamber via a biting edge of a sealing sleeve.
  • the sealing sleeve in turn serves to guide the valve pin axially displaceably arranged valve pin and the hydraulic separation of the lower end face of the valve chamber.
  • a shim is arranged, against which at the same time an end face of the compression spring is supported, wherein the shim limiting the maximum opening stroke of the valve pin is used when it rests with its lower end face on the shim.
  • the compression spring is arranged within the region of a low-pressure region in the region of a guide body whose spherically formed bottom bears against the bottom of the low-pressure region in order to be able to compensate for tilting movements or plane errors of the bottom of the low-pressure region.
  • the invention has the object, a fuel injector according to the preamble of claim 1 such that a particularly simple or inexpensive adjustment of the opening stroke of the valve pin is achieved.
  • This object is achieved in a fuel injector with the features of claim 1, characterized in that the opening stroke is effected by an at least indirect concern of the valve pin on the sealing sleeve.
  • this means that the setting of the stroke of the valve pin is shifted out of the low pressure area in the valve chamber, so that the setting of the valve lift can be independent of the components arranged in the low pressure region and their accuracy, and thus relatively inexpensive.
  • it is thus sufficient to design the valve sleeve radially enclosing valve sleeve with respect to its length with a desired or required accuracy, so that a certain opening stroke of the valve pin is achieved.
  • the stroke limiter be effected by means of a shim which is arranged in the valve chamber.
  • the manufacture of the sealing sleeve can be subject to greater tolerances with regard to its length, which reduces its production costs.
  • this makes it possible, for example, to form the sealing sleeve and the adjusting disk made of different materials, wherein the adjusting disk is designed, for example, with a particularly wear-resistant or hard surface is to avoid wear on the impact of the valve pin on the shim or minimize.
  • the sealing sleeve may consist, for example, of a material softer or different from the adjusting disk.
  • the shim is arranged on the valve seat surface side facing the sealing sleeve and cooperating to form the stroke stop with an enlarged diameter portion of the valve pin.
  • the compression spring in the low-pressure region usually has a diameter, which is greater than the diameter of the valve pin, relative to the valve pin in the valve chamber.
  • a preferably disc-shaped transmission body is arranged in the low pressure region, which is loaded by the spring force of the compression spring on the end facing away from the valve face Valve pin rests.
  • the reaction rate of the actuated by the control valve, downstream high-pressure hydraulics on the valve pin movement depends in particular on the fuel volume in the valve chamber.
  • the sealing sleeve on the side facing the compression spring has a biting edge which rests sealingly on an end face of the valve chamber.
  • the compression spring rests on the side facing away from the valve pin on a spring support element.
  • This spring support element in particular forms a plane or even support for the compression spring.
  • a further improvement of the leadership of the compression spring is achieved when the spring support member is part of a guide member having a preferably pin-shaped guide portion which is radially surrounded by the compression spring.
  • a further improvement of the leadership of the compression spring by the spring support member is achieved when the spring support member on the side facing away from the compression spring has a radially circumferential chamfer.
  • a diameter of the sealing seat between the valve pin and the valve seat surface is greater than a diameter of a guide bore of the sealing sleeve, in which the valve pin is guided.
  • a first inventive fuel injector 1 is shown in fragmentary form, as it is used in particular for self-igniting internal combustion engines for injection into the combustion chamber of the internal combustion engine.
  • a preferred use of the fuel injector 1 is for a fuel injection system with a common rail, which leads the diesel fuel under high pressure to a plurality of fuel injectors 1.
  • the fuel injector 1 has a housing in which a throttle plate 2 and a valve plate 3 are arranged.
  • the throttle plate 2 has an end face 4.
  • the valve plate 3 has an end face 5, wherein the throttle plate 2 rests with its end face 4 on the end face 5 of the valve plate 3.
  • the throttle plate 2 facing away from the front side 4, another end face 6.
  • the channel section 7 has an inlet throttle 9 formed in the throttle plate 2.
  • the control chamber 8 is limited on the one hand by the end face 6 of the throttle plate 2, and on the other hand by an end face 10 of a nozzle needle 11 and laterally by a sleeve 12.
  • the sleeve 12 is located on the end face 6 of the throttle plate 2. According to the pressure in the control chamber 8, the nozzle needle 11 is held in a closed position or opened against the closing direction 13.
  • the pressure of the fuel in the control chamber 8 acts against a fuel pressure in a fuel chamber 14 and a nozzle spring tension. Due to the pending on the valve chamber end of the guide gap 48 high pressure creates a slight leakage flow through the guide gap 48 to the pressure-relieved space 27th
  • the control valve 15 has a valve chamber 16 which is formed in the valve plate 3.
  • the valve chamber 16 is bounded by an inner wall 17, which is formed on the valve plate 3 and a sealing surface 18, which is part of the end face 4 of the throttle plate 2.
  • valve pin 20 In the valve chamber 16, a sealing sleeve 19 and at least partially a valve pin 20 are arranged.
  • the valve pin 20 is guided in a guide bore 22 of the sealing sleeve 19.
  • the control valve 15 has a longitudinal axis 23 along which the valve pin 20 can be actuated.
  • the valve plate 3 has a recess 24 into which a drain hole 25 opens.
  • the drain hole 25 is connected via the recess 24 on the one hand with the valve chamber 16.
  • the drain hole 25 opens into the control chamber 8.
  • the drain hole 25 has an outlet throttle 26.
  • the drain hole connects 25, the control chamber 8 with the valve chamber 16.
  • the drain hole 25 is formed with the outlet throttle 26 in this embodiment in the throttle plate 2.
  • a low pressure area in the form of a pressure-relieved space 27 is also formed, which is connected via a return passage 28 with a low pressure return or the like.
  • the pressure-relieved space 27 thus forms a low-pressure region.
  • a guide member 29 for a compression spring 30 is arranged in the pressure-relieved space 27.
  • the guide element 29 has a pin-shaped guide section 31, which is radially surrounded by the compression spring 30.
  • the guide element 29 In the direction of the bottom 32 of the pressure-relieved space 27, which is designed in the form of a blind hole, the guide element 29 has a spring support element 33, which is integrally formed on the guide section 31.
  • the spring support element 33 has on the bottom 32 of the pressure-relieved space 27 side facing a radially encircling chamfer 34.
  • the compression spring 30 is supported with its one end face against the spring support element 33 and with its other end face against a disc-shaped transfer body 35 from.
  • Both the transmission body 35, and the spring support element 33 have a diameter which is preferably only slightly smaller than the inner diameter of the pressure-relieved space 27, in the transition region between its radially encircling inner wall toward the base 32 with a rounded edge 36 in the region Bevel 34 is formed.
  • the sealing sleeve 19 has on the compression spring 30 facing the end face a radially circumferential biting edge 38 which bears sealingly against the end face 4 of the throttle plate 2.
  • the valve plate 3 has a partially conical contact surface 40. Further, a valve seat surface 41 is formed on the valve plate 3, which is part of the conical bearing surface 40. The valve pin 20 cooperates with the valve seat surface 41 to form a sealing seat 42. In the unactuated state of the control valve 15, the sealing seat 42 is closed. In this case, on the one hand, the force of the compression spring 30 acts in the closing direction 13, on the other hand, during operation, a hydraulic force caused by the pressure of the fuel acts in the direction of the closed position 43.
  • a fuel gap 46 is formed between the inner wall 17 and an outer side 45 of the sealing sleeve 19, a fuel gap 46 is formed.
  • the fuel gap 46 is formed as an annular fuel gap 46. Via the fuel gap 46, the fuel passes from the drainage bore 25 to a passage gap 47 in the region of the conical contact surface 40. Via the passage gap 47, the fuel in turn passes into a guide gap 48 which is formed between the sealing sleeve 19 and the valve pin 20.
  • the actuation of the valve pin 20 is effected by an actuator 55, which acts on a transition piece 59 against the closing direction 43.
  • the actuator 55 may be formed as a piezoelectric actuator (preferably with a hydraulic coupler) or as a magnetic actuator.
  • an enlarged diameter portion 60 of the valve pin 20 cooperates with its underside 61 at least indirectly with the sealing sleeve 19.
  • a dial 65 is arranged between the bottom 61 and the portion 60 facing end face of the sealing sleeve 19.
  • the thickness 66 of the dial 65 results from the geometric dimensions of the valve chamber 16, in particular the height between the end 4 to the valve seat 41 and the height of the sealing sleeve 19. It is essential that in the open position of the valve pin 20, in the actuated actuator 55 the bottom 61 of the valve pin 20 rests on the top of the dial 65, between the compression spring 30 facing underside of the transfer body 35 and the guide member 29 still a gap 67 remains.
  • valve pin 20 and the adjusting disk 65 and / or between the adjusting disk 65 and the sealing sleeve 19 are particularly advantageous.
  • at least one contact surface between the valve pin 20 and the adjusting disk 65 and / or between the adjusting disk 65 and the sealing sleeve 19 with at least one radially circumferential groove, which in the illustration of Fig. 1 is not recognizable.
  • the guide member 29a only a spring receiving element 33a, but no guide portion 31 corresponding to the fuel injector 1.
  • the fuel injectors 1, 1a and 1b described so far can be modified or modified in a variety of ways. This is to adjust the stroke stop for the valve pin 20 in its open position by a corresponding dimensioning of the sealing sleeve 19, but in particular by the dimensioning of a dial 65 which is disposed between the sealing sleeve 19 and the throttle plate 2 and the pressure-relieved space 27. So it is also within the scope of the invention to dispense with the dial 65, and form the stroke limiter of the valve pin 20 by a correspondingly accurate production of the length or height of the sealing sleeve 19.
  • the contact surfaces between the sealing sleeve 19 and the shim 65 and / or between the shim 65 and the valve pin 20 may each be flat or conical.
  • the cone angles can each be selected such that a true contact surface is formed, but also in such a way that a contact line is formed.

Description

Stand der TechnikState of the art

Die Erfindung betrifft einen Kraftstoffinjektor nach dem Oberbegriff des Anspruchs 1.The invention relates to a fuel injector according to the preamble of claim 1.

Ein derartiger Kraftstoffinjektor ist aus der DE 10 2010 063 540 A1 der Anmelderin bekannt. Bei dem bekannten Kraftstoffinjektor ist es zur Verringerung des Kraftstoffvolumens im Ventilraum vorgesehen, dass eine den Ventilbolzen in seine Schließstellung mit Federkraft beaufschlagende Druckfeder in einem vom Ventilraum getrennten Niederdruckbereich angeordnet ist, wobei der Niederdruckbereich über eine Beißkante einer Dichthülse hydraulisch von dem Ventilraum getrennt ist. Die Dichthülse wiederum dient der Führung des im Ventilraum axial verschiebbar angeordneten Ventilbolzens und der hydraulischen Trennung von dessen unterer Stirnfläche von dem Ventilraum.Such a fuel injector is from the DE 10 2010 063 540 A1 the applicant known. In the known fuel injector, it is provided to reduce the fuel volume in the valve chamber, that a pressure spring acting on the valve pin in its closed position in a low pressure region separated from the valve chamber is arranged, wherein the low pressure region is hydraulically separated from the valve chamber via a biting edge of a sealing sleeve. The sealing sleeve in turn serves to guide the valve pin axially displaceably arranged valve pin and the hydraulic separation of the lower end face of the valve chamber.

Bei dem bekannten Kraftstoffinjektor ist es vorgesehen, dass innerhalb des Niederdruckbereichs eine Einstellscheibe angeordnet ist, gegen die sich gleichzeitig eine Stirnseite der Druckfeder abstützt, wobei die Einstellscheibe der Begrenzung des maximalen Öffnungshubs des Ventilbolzens dient, wenn dieser mit seiner unteren Stirnseite an der Einstellscheibe anliegt. Die Druckfeder ist innerhalb des Niederdruckbereichs im Bereich eines Führungskörpers angeordnet, dessen sphärisch ausgebildete Unterseite am Grund des Niederdruckbereichs anliegt, um Kippbewegungen bzw. Planfehler des Grundes des Niederdruckbereichs ausgleichen zu können.In the known fuel injector, it is provided that within the low pressure region, a shim is arranged, against which at the same time an end face of the compression spring is supported, wherein the shim limiting the maximum opening stroke of the valve pin is used when it rests with its lower end face on the shim. The compression spring is arranged within the region of a low-pressure region in the region of a guide body whose spherically formed bottom bears against the bottom of the low-pressure region in order to be able to compensate for tilting movements or plane errors of the bottom of the low-pressure region.

Nachteilig dabei ist, dass die Einstellung des maximalen Öffnungshubs des Ventilbolzens insofern relativ aufwendig ist, als dass die verwendete Einstellscheibe von der Genauigkeit der Ausbildung des Niederdruckbereichs, insbesondere von dessen Tiefe, sowie von der Genauigkeit der Fertigung des Führungskörpers abhängig ist. Man könnte nun zwar versuchen, durch eine plane bzw. ebene Fläche am Grund des Niederdruckbereichs eine einfachere Fertigung des Führungskörpers zu ermöglichen, eine derartige plane Oberfläche am Grund des Niederdruckbereichs ist jedoch mittels einer Bohr- bzw. Drehbearbeitung nicht zu fertigen, vielmehr müsste die Fläche plan geschliffen werden, was jedoch aus Kostengründen ausscheidet. Ein anderes Beispiel ist aus dem DE 10 2010 040 874 A1 bekannt.The disadvantage here is that the adjustment of the maximum opening stroke of the valve pin is relatively complicated insofar as that the dial used depends on the accuracy of the formation of the low pressure region, in particular its depth, as well as the accuracy of the production of the guide body. you Although now could try to allow by a plane or flat surface at the bottom of the low pressure area easier production of the guide body, however, such a flat surface at the bottom of the low pressure area is not finished by means of drilling or turning, but the surface should plan be sanded, but this eliminates cost reasons. Another example is from the DE 10 2010 040 874 A1 known.

Offenbarung der ErfindungDisclosure of the invention

Ausgehend von dem dargestellten Stand der Technik liegt der Erfindung die Aufgabe zugrunde, einen Kraftstoffinjektor nach dem Oberbegriff des Anspruchs 1 derart weiterzubilden, dass eine besonders einfache bzw. kostengünstige Einstellung des Öffnungshubs des Ventilbolzens erzielt wird. Diese Aufgabe wird erfindungsgemäß bei einem Kraftstoffinjektor mit den Merkmalen des Anspruchs 1 dadurch gelöst, dass der Öffnungshub durch ein zumindest mittelbares Anliegen des Ventilbolzens an der Dichthülse erfolgt. Mit anderen Worten gesagt bedeutet dies, dass die Einstellung des Hubs des Ventilbolzens aus dem Niederdruckbereich heraus in den Ventilraum verlagert wird, so dass die Einstellung des Ventilhubes unabhängig von den in dem Niederdruckbereich angeordneten Bauteilen und deren Genauigkeit, und somit relativ kostengünstig, erfolgen kann. Bei der Grundidee der Erfindung genügt es somit, die den Ventilbolzen radial umfassende Ventilhülse hinsichtlich ihrer Länge mit einer gewünschten bzw. erforderlichen Genauigkeit auszubilden, damit ein bestimmter Öffnungshub des Ventilbolzens erzielt wird.Based on the illustrated prior art, the invention has the object, a fuel injector according to the preamble of claim 1 such that a particularly simple or inexpensive adjustment of the opening stroke of the valve pin is achieved. This object is achieved in a fuel injector with the features of claim 1, characterized in that the opening stroke is effected by an at least indirect concern of the valve pin on the sealing sleeve. In other words, this means that the setting of the stroke of the valve pin is shifted out of the low pressure area in the valve chamber, so that the setting of the valve lift can be independent of the components arranged in the low pressure region and their accuracy, and thus relatively inexpensive. In the basic idea of the invention, it is thus sufficient to design the valve sleeve radially enclosing valve sleeve with respect to its length with a desired or required accuracy, so that a certain opening stroke of the valve pin is achieved.

Vorteilhafte Weiterbildungen des erfindungsgemäßen Kraftstoffinjektors sind in den Unteransprüchen angegeben. In den Rahmen der Erfindung fallen sämtliche Kombinationen aus zumindest zwei von in den Ansprüchen, der Beschreibung und/oder den Figuren offenbarten Merkmalen.Advantageous developments of the fuel injector according to the invention are specified in the subclaims. All combinations of at least two of the features disclosed in the claims, the description and / or the figures fall within the scope of the invention.

In einer ganz besonders bevorzugten konstruktiven Umsetzung der Erfindung wird vorgeschlagen, dass die Hubbegrenzung mittels einer Einstellscheibe erfolgt, die im Ventilraum angeordnet ist. Dadurch kann die Fertigung der Dichthülse hinsichtlich ihrer Länge mit größeren Toleranzen behaftet sein, was deren Herstellkosten verringert. Weiterhin wird es dadurch beispielsweise ermöglicht, die Dichthülse und die Einstellscheibe aus unterschiedlichem Material auszubilden, wobei die Einstellscheibe beispielsweise mit einer besonders verschleißfesten bzw. harten Oberfläche ausgestaltet ist, um Verschleißerscheinungen beim Auftreffen des Ventilbolzens an der Einstellscheibe zu vermeiden bzw. zu minimieren. Demgegenüber kann die Dichthülse beispielsweise aus einem gegenüber der Einstellscheibe weicherem bzw. anderem Material bestehen.In a very particularly preferred structural implementation of the invention, it is proposed that the stroke limiter be effected by means of a shim which is arranged in the valve chamber. As a result, the manufacture of the sealing sleeve can be subject to greater tolerances with regard to its length, which reduces its production costs. Furthermore, this makes it possible, for example, to form the sealing sleeve and the adjusting disk made of different materials, wherein the adjusting disk is designed, for example, with a particularly wear-resistant or hard surface is to avoid wear on the impact of the valve pin on the shim or minimize. In contrast, the sealing sleeve may consist, for example, of a material softer or different from the adjusting disk.

Bei letztgenannter Variante unter Benutzung einer Einstellscheibe ist es besonders bevorzugt vorgesehen, dass die Einstellscheibe auf der der Ventilsitzfläche zugewandten Seite der Dichthülse angeordnet ist und zur Ausbildung des Hubanschlags mit einem im Durchmesser vergrößerten Abschnitt des Ventilbolzens zusammenwirkt.In the latter variant using a shim, it is particularly preferably provided that the shim is arranged on the valve seat surface side facing the sealing sleeve and cooperating to form the stroke stop with an enlarged diameter portion of the valve pin.

Die Druckfeder im Niederdruckbereich weist gegenüber dem Ventilbolzen im Ventilraum üblicherweise einen Durchmesser auf, der größer ist als der Durchmesser des Ventilbolzens. Um eine einfache Übertragung der Federkraft von der Druckfeder auf den Ventilbolzen zu ermöglichen, ist es daher vorgesehen, dass zwischen der Druckfeder und dem Ventilbolzen ein vorzugsweise scheibenförmiger Übertragungskörper im Niederdruckbereich angeordnet ist, der von der Federkraft der Druckfeder belastet an der der Ventilfläche abgewandten Stirnseite des Ventilbolzens anliegt.The compression spring in the low-pressure region usually has a diameter, which is greater than the diameter of the valve pin, relative to the valve pin in the valve chamber. In order to enable a simple transmission of the spring force of the compression spring on the valve pin, it is therefore provided that between the compression spring and the valve pin, a preferably disc-shaped transmission body is arranged in the low pressure region, which is loaded by the spring force of the compression spring on the end facing away from the valve face Valve pin rests.

Die Reaktionsgeschwindigkeit der von dem Steuerventil betätigten, nachgeschalteten Hochdruckhydraulik auf die Ventilbolzenbewegung hängt insbesondere von dem Kraftstoffvolumen im Ventilraum ab. Um den Ventilraum zur Erzielung eines möglichst geringen Kraftstoffvolumens gegenüber dem Niederdruckbereich abzudichten ist es daher in einer weiteren Ausgestaltung der Erfindung vorgesehen, dass die Dichthülse auf der der Druckfeder zugewandten Seite eine Beißkante aufweist, die an einer Stirnfläche des Ventilraums dichtend anliegt.The reaction rate of the actuated by the control valve, downstream high-pressure hydraulics on the valve pin movement depends in particular on the fuel volume in the valve chamber. In order to seal the valve space to achieve the lowest possible fuel volume compared to the low-pressure region, it is therefore provided in a further embodiment of the invention that the sealing sleeve on the side facing the compression spring has a biting edge which rests sealingly on an end face of the valve chamber.

Um unabhängig von der Genauigkeit der Ausbildung des Grundes des Niederdruckbereichs eine möglichst gute Ausrichtung der Druckfeder zur Längsachse des Ventilbolzens zu ermöglichen, ist es in einer weiteren Ausgestaltung der Erfindung vorgesehen, dass die Druckfeder auf der dem Ventilbolzen abgewandten Seite an einem Federauflageelement anliegt. Dieses Federauflageelement bildet insbesondere eine plane bzw. ebene Auflage für die Druckfeder aus.In order to enable the best possible alignment of the compression spring to the longitudinal axis of the valve pin regardless of the accuracy of the formation of the bottom of the low pressure region, it is provided in a further embodiment of the invention that the compression spring rests on the side facing away from the valve pin on a spring support element. This spring support element in particular forms a plane or even support for the compression spring.

Eine weitere Verbesserung der Führung der Druckfeder wird erzielt, wenn das Federauflageelement Teil eines Führungselements ist, das einen vorzugsweise zapfenförmigen Führungsabschnitt aufweist, der von der Druckfeder radial umfasst ist.A further improvement of the leadership of the compression spring is achieved when the spring support member is part of a guide member having a preferably pin-shaped guide portion which is radially surrounded by the compression spring.

Eine nochmalige Verbesserung der Führung der Druckfeder durch das Federauflageelement wird erzielt, wenn das Federauflageelement auf der der Druckfeder abgewandten Seite eine radial umlaufende Fase aufweist. Dadurch liegt das Federauflageelement auch bei relativ großem Durchmesser, insbesondere einem Durchmesser der zumindest nahezu dem Durchmesser des Niederdruckbereichs entspricht, bündig am Grund des Niederdruckbereichs auf, da ein Übergangsbereich von der umlaufenden Seitenwand zum Grund vorhandene, fertigungstechnisch bedingte Ausrundung keinen Einfluss auf die plane Ausrichtung des Federauflageelements am Grund des Niederdruckbereichs hat.A further improvement of the leadership of the compression spring by the spring support member is achieved when the spring support member on the side facing away from the compression spring has a radially circumferential chamfer. As a result, even with a relatively large diameter, in particular a diameter which corresponds at least almost to the diameter of the low-pressure region, the spring-contact element is flush with the bottom of the low-pressure region, since a transitional region from the circumferential side wall to the base does not influence the flat alignment of the production-related rounding Spring support element has at the bottom of the low pressure area.

Zur Erhöhung der Schließkraft des Ventilbolzens in Richtung der Ventilsitzfläche durch Ausbildung einer hydraulischen Schließkraft wird darüber hinaus vorgeschlagen, dass ein Durchmesser des Dichtsitzes zwischen dem Ventilbolzen und der Ventilsitzfläche größer ist als ein Durchmesser einer Führungsbohrung der Dichthülse, in der der Ventilbolzen geführt ist.To increase the closing force of the valve pin in the direction of the valve seat surface by forming a hydraulic closing force is also proposed that a diameter of the sealing seat between the valve pin and the valve seat surface is greater than a diameter of a guide bore of the sealing sleeve, in which the valve pin is guided.

Weitere Vorteile, Merkmale und Einzelheiten der Erfindung ergeben sich aus der nachfolgenden Beschreibung bevorzugter Ausführungsbeispiele sowie anhand der Zeichnung.Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawing.

Diese zeigt in:

Fig. 1
einen Ausschnitt eines ersten erfindungsgemäßen Kraftstoffinjektors im Bereich des Steuerventils im Längsschnitt und
Fig. 2 und 3
jeweils modifizierte Kraftstoffinjektoren, bei denen die Anordnung der Druckfeder im Niederdruckbereich sich von der Anordnung der Druckfeder im Niederdruckbereich gemäß der Fig. 1 unterscheidet, ebenfalls im Längsschnitt.
This shows in:
Fig. 1
a detail of a first fuel injector according to the invention in the region of the control valve in longitudinal section and
FIGS. 2 and 3
each modified fuel injectors, in which the arrangement of the compression spring in the low-pressure region of the arrangement of the compression spring in the low-pressure region according to the Fig. 1 different, also in longitudinal section.

Gleiche Bauteile bzw. Bauteile mit gleicher Funktion sind in den Figuren mit den gleichen Bezugsziffern versehen.The same components or components with the same function are provided in the figures with the same reference numerals.

In der Fig. 1 ist ein erster erfindungsgemäßer Kraftstoffinjektor 1 ausschnittsweise dargestellt, wie er insbesondere für selbstzündende Brennkraftmaschinen zum Einspritzen in den Brennraum der Brennkraftmaschine dient. Ein bevorzugter Einsatz des Kraftstoffinjektors 1 besteht für eine Brennstoffeinspritzanlage mit einem Common-Rail, das den Dieselbrennstoff unter hohem Druck zu mehreren Kraftstoffinjektoren 1 führt. Der Kraftstoffinjektor 1 weist ein Gehäuse auf, in dem eine Drosselplatte 2 und eine Ventilplatte 3 angeordnet sind. Hierbei weist die Drosselplatte 2 eine Stirnseite 4 auf. Ferner weist die Ventilplatte 3 eine Stirnseite 5 auf, wobei die Drosselplatte 2 mit ihrer Stirnseite 4 an der Stirnseite 5 der Ventilplatte 3 anliegt. Weiterhin weist die Drosselplatte 2 eine von der Stirnseite 4 abgewandte, weitere Stirnseite 6 auf.In the Fig. 1 a first inventive fuel injector 1 is shown in fragmentary form, as it is used in particular for self-igniting internal combustion engines for injection into the combustion chamber of the internal combustion engine. A preferred use of the fuel injector 1 is for a fuel injection system with a common rail, which leads the diesel fuel under high pressure to a plurality of fuel injectors 1. The fuel injector 1 has a housing in which a throttle plate 2 and a valve plate 3 are arranged. In this case, the throttle plate 2 has an end face 4. Further, the valve plate 3 has an end face 5, wherein the throttle plate 2 rests with its end face 4 on the end face 5 of the valve plate 3. Furthermore, the throttle plate 2 facing away from the front side 4, another end face 6.

Beim Betrieb des Kraftstoffinjektors 1 wird von einer durch den Kraftstoffinjektor 1 geführten Brennstoffleitung über einen Kanalabschnitt 7, der durch die Drosselplatte 2 geführt ist, Brennstoff in einen Steuerraum 8 geführt. Hierbei weist der Kanalabschnitt 7 eine in der Drosselplatte 2 ausgebildete Zulaufdrossel 9 auf. Der Steuerraum 8 ist einerseits durch die Stirnseite 6 der Drosselplatte 2, und andererseits durch eine Stirnfläche 10 einer Düsennadel 11 sowie seitlich durch eine Hülse 12 begrenzt. Die Hülse 12 liegt an der Stirnseite 6 der Drosselplatte 2 an. Entsprechend dem Druck im Steuerraum 8 wird die Düsennadel 11 in einer Schließstellung gehalten oder entgegen der Schließrichtung 13 geöffnet. Der Druck des Brennstoffs im Steuerraum 8 wirkt hierbei gegen einen Brennstoffdruck in einem Brennstoffraum 14 und eine Düsenfederspannung. Aufgrund des an dem ventilraumseitigen Ende des Führungsspalts 48 anstehenden hohen Drucks entsteht ein geringfügiger Leckagestrom durch den Führungsspalt 48 zum druckentlasteten Raum 27.During operation of the fuel injector 1, fuel is guided into a control chamber 8 by a fuel line routed through the fuel injector 1 via a channel section 7 which is guided through the throttle plate 2. In this case, the channel section 7 has an inlet throttle 9 formed in the throttle plate 2. The control chamber 8 is limited on the one hand by the end face 6 of the throttle plate 2, and on the other hand by an end face 10 of a nozzle needle 11 and laterally by a sleeve 12. The sleeve 12 is located on the end face 6 of the throttle plate 2. According to the pressure in the control chamber 8, the nozzle needle 11 is held in a closed position or opened against the closing direction 13. The pressure of the fuel in the control chamber 8 acts against a fuel pressure in a fuel chamber 14 and a nozzle spring tension. Due to the pending on the valve chamber end of the guide gap 48 high pressure creates a slight leakage flow through the guide gap 48 to the pressure-relieved space 27th

Zum Steuern des Brennstoffdrucks im Steuerraum 8 dient ein Steuerventil 15. Das Steuerventil 15 weist einen Ventilraum 16 auf, der in der Ventilplatte 3 ausgebildet ist. Der Ventilraum 16 ist durch eine Innenwand 17, die an der Ventilplatte 3 ausgebildet ist und eine Dichtfläche 18 begrenzt, die Teil der Stirnseite 4 der Drosselplatte 2 ist.For controlling the fuel pressure in the control chamber 8 is a control valve 15. The control valve 15 has a valve chamber 16 which is formed in the valve plate 3. The valve chamber 16 is bounded by an inner wall 17, which is formed on the valve plate 3 and a sealing surface 18, which is part of the end face 4 of the throttle plate 2.

In dem Ventilraum 16 sind eine Dichthülse 19 und zumindest abschnittsweise ein Ventilbolzen 20 angeordnet. Der Ventilbolzen 20 ist in einer Führungsbohrung 22 der Dichthülse 19 geführt. Das Steuerventil 15 weist eine Längsachse 23 auf, entlang der der Ventilbolzen 20 betätigbar ist.In the valve chamber 16, a sealing sleeve 19 and at least partially a valve pin 20 are arranged. The valve pin 20 is guided in a guide bore 22 of the sealing sleeve 19. The control valve 15 has a longitudinal axis 23 along which the valve pin 20 can be actuated.

Die Ventilplatte 3 weist eine Ausnehmung 24 auf, in die eine Ablaufbohrung 25 mündet. Die Ablaufbohrung 25 ist über die Ausnehmung 24 einerseits mit dem Ventilraum 16 verbunden. Andererseits mündet die Ablaufbohrung 25 in den Steuerraum 8. Die Ablaufbohrung 25 weist eine Ablaufdrossel 26 auf. Somit verbindet die Ablaufbohrung 25 den Steuerraum 8 mit dem Ventilraum 16. Die Ablaufbohrung 25 ist mit der Ablaufdrossel 26 in diesem Ausführungsbeispiel in der Drosselplatte 2 ausgebildet.The valve plate 3 has a recess 24 into which a drain hole 25 opens. The drain hole 25 is connected via the recess 24 on the one hand with the valve chamber 16. On the other hand, the drain hole 25 opens into the control chamber 8. The drain hole 25 has an outlet throttle 26. Thus, the drain hole connects 25, the control chamber 8 with the valve chamber 16. The drain hole 25 is formed with the outlet throttle 26 in this embodiment in the throttle plate 2.

In der Drosselplatte 2 ist außerdem ein Niederdruckbereich in Form eines druckentlasteten Raums 27 ausgebildet, der über einen Rücklaufkanal 28 mit einem Niederdruckrücklauf oder dergleichen verbunden ist. Der druckentlastete Raum 27 bildet somit einen Niederdruckbereich aus. In dem druckentlasteten Raum 27 ist ein Führungselement 29 für eine Druckfeder 30 angeordnet. Hierbei weist das Führungselement 29 einen zapfenförmigen Führungsabschnitt 31 auf, der von der Druckfeder 30 radial umfasst ist. In Richtung des Grundes 32 des druckentlasteten Raums 27, der in Form einer Sacklochbohrung ausgebildet ist, weist das Führungselement 29 ein Federauflageelement 33 auf, das einstückig am Führungsabschnitt 31 angeformt ist. Das Federauflageelement 33 weist auf der dem Grund 32 des druckentlasteten Raums 27 zugewandten Seite eine radial umlaufende Fase 34 auf.In the throttle plate 2, a low pressure area in the form of a pressure-relieved space 27 is also formed, which is connected via a return passage 28 with a low pressure return or the like. The pressure-relieved space 27 thus forms a low-pressure region. In the pressure-relieved space 27, a guide member 29 for a compression spring 30 is arranged. In this case, the guide element 29 has a pin-shaped guide section 31, which is radially surrounded by the compression spring 30. In the direction of the bottom 32 of the pressure-relieved space 27, which is designed in the form of a blind hole, the guide element 29 has a spring support element 33, which is integrally formed on the guide section 31. The spring support element 33 has on the bottom 32 of the pressure-relieved space 27 side facing a radially encircling chamfer 34.

Die Druckfeder 30 stützt sich mit ihrer einen Stirnseite gegen das Federauflageelement 33 und mit ihrer anderen Stirnseite gegen einen scheibenförmigen Übertragungskörper 35 ab. Sowohl der Übertragungskörper 35, als auch das Federauflageelement 33 weisen einen Durchmesser auf, der vorzugsweise lediglich etwas kleiner ist als der Innendurchmesser des druckentlasteten Raums 27, der im Übergangsbereich zwischen seiner radial umlaufenden Innenwand zum Grund 32 hin mit einer gerundet ausgebildeten Kante 36 im Bereich der Fase 34 ausgebildet ist.The compression spring 30 is supported with its one end face against the spring support element 33 and with its other end face against a disc-shaped transfer body 35 from. Both the transmission body 35, and the spring support element 33 have a diameter which is preferably only slightly smaller than the inner diameter of the pressure-relieved space 27, in the transition region between its radially encircling inner wall toward the base 32 with a rounded edge 36 in the region Bevel 34 is formed.

Die Dichthülse 19 weist auf der der Druckfeder 30 zugewandten Stirnseite eine radial umlaufende Beißkante 38 auf, die an der Stirnseite 4 der Drosselplatte 2 dichtend anliegt.The sealing sleeve 19 has on the compression spring 30 facing the end face a radially circumferential biting edge 38 which bears sealingly against the end face 4 of the throttle plate 2.

Die Ventilplatte 3 weist eine teilweise kegelförmige Anlagefläche 40 auf. Ferner ist an der Ventilplatte 3 eine Ventilsitzfläche 41 ausgebildet, die Teil der kegelförmigen Anlagefläche 40 ist. Der Ventilbolzen 20 wirkt mit der Ventilsitzfläche 41 zu einem Dichtsitz 42 zusammen. In unbetätigtem Zustand des Steuerventils 15 ist der Dichtsitz 42 geschlossen. Hierbei wirkt zum Einen die Kraft der Druckfeder 30 in die Schließrichtung 13, zum Anderen wirkt beim Betrieb eine durch den Druck des Brennstoffs bedingte hydraulische Kraft in Richtung der Schließstellung 43.The valve plate 3 has a partially conical contact surface 40. Further, a valve seat surface 41 is formed on the valve plate 3, which is part of the conical bearing surface 40. The valve pin 20 cooperates with the valve seat surface 41 to form a sealing seat 42. In the unactuated state of the control valve 15, the sealing seat 42 is closed. In this case, on the one hand, the force of the compression spring 30 acts in the closing direction 13, on the other hand, during operation, a hydraulic force caused by the pressure of the fuel acts in the direction of the closed position 43.

Zwischen der Innenwand 17 und einer Außenseite 45 der Dichthülse 19 ist ein Brennstoffspalt 46 ausgebildet. In diesem Ausführungsbeispiel ist der Brennstoffspalt 46 als ringförmiger Brennstoffspalt 46 ausgebildet. Über den Brennstoffspalt 46 gelangt der Brennstoff aus der Ablaufbohrung 25 zu einem Durchgangsspalt 47 im Bereich der kegelförmigen Anlagefläche 40. Über den Durchgangsspalt 47 gelangt der Brennstoff wiederum in einen Führungsspalt 48, der zwischen der Dichthülse 19 und dem Ventilbolzen 20 ausgebildet ist.Between the inner wall 17 and an outer side 45 of the sealing sleeve 19, a fuel gap 46 is formed. In this embodiment, the fuel gap 46 is formed as an annular fuel gap 46. Via the fuel gap 46, the fuel passes from the drainage bore 25 to a passage gap 47 in the region of the conical contact surface 40. Via the passage gap 47, the fuel in turn passes into a guide gap 48 which is formed between the sealing sleeve 19 and the valve pin 20.

Beim Betrieb des Kraftstoffinjektors 1 wird unter Hochdruck stehender Brennstoff über die Zulaufdrossel 9 in den Steuerraum 8 geführt. Somit stellt sich auch im Brennstoffspalt 46 ein hoher Brennstoffdruck ein. Dieser hohe Brennstoffdruck wirkt über den Durchgangsspalt 47 auch im Führungsspalt 48. Aufgrund des geschlossenen Dichtsitzes 42 ist eine Abdichtung gegenüber einem Niederdruckraum 49 gewährleistet, der jenseits des Dichtsitzes 42 an den Ventilbolzen 20 angrenzt. Da ein Durchmesser 51 des Ventilbolzens 20 kleiner ist als ein Durchmesser 52 des Dichtsitzes 42 ergibt sich durch den Druck des Brennstoffs eine hydraulische Schließkraft in der Schließrichtung 43.During operation of the fuel injector 1, high-pressure fuel is conducted via the inlet throttle 9 into the control chamber 8. Thus, also in the fuel gap 46, a high fuel pressure. This high fuel pressure acts on the passage gap 47 in the guide gap 48. Due to the closed sealing seat 42 a seal against a low-pressure chamber 49 is ensured, which adjoins the valve pin 20 beyond the sealing seat 42. Since a diameter 51 of the valve pin 20 is smaller than a diameter 52 of the sealing seat 42 results from the pressure of the fuel, a hydraulic closing force in the closing direction 43rd

Die Betätigung des Ventilbolzens 20 erfolgt durch einen Aktor 55, der auf ein Übergangsstück 59 entgegen der Schließrichtung 43 wirkt. Der Aktor 55 kann als Piezoaktor (vorzugsweise mit hydraulischem Koppler) oder auch als Magnetaktor ausgebildet sein.The actuation of the valve pin 20 is effected by an actuator 55, which acts on a transition piece 59 against the closing direction 43. The actuator 55 may be formed as a piezoelectric actuator (preferably with a hydraulic coupler) or as a magnetic actuator.

Zur Begrenzung des Öffnungshubes des Ventilbolzens 20 bei betätigtem Aktor 55 wirkt ein im Durchmesser vergrößerter Abschnitt 60 des Ventilbolzens 20 mit seiner Unterseite 61 zumindest mittelbar mit der Dichthülse 19 zusammen. Hierzu ist zwischen der Unterseite 61 und der dem Abschnitt 60 zugewandten Stirnfläche der Dichthülse 19 eine Einstellscheibe 65 angeordnet. Die Dicke 66 der Einstellscheibe 65 ergibt sich aus den geometrischen Abmessungen des Ventilraums 16, insbesondere der Höhe zwischen der Stirnseite 4 zur Ventilsitzfläche 41 und der Höhe der Dichthülse 19. Wesentlich dabei ist, dass in der Öffnungsstellung des Ventilbolzens 20, in der bei betätigtem Aktor 55 die Unterseite 61 des Ventilbolzens 20 auf der Oberseite der Einstellscheibe 65 anliegt, zwischen der der Druckfeder 30 zugewandten Unterseite des Übertragungskörpers 35 und dem Führungselement 29 noch ein Spalt 67 verbleibt.In order to limit the opening stroke of the valve pin 20 when the actuator 55 is actuated, an enlarged diameter portion 60 of the valve pin 20 cooperates with its underside 61 at least indirectly with the sealing sleeve 19. For this purpose, a dial 65 is arranged between the bottom 61 and the portion 60 facing end face of the sealing sleeve 19. The thickness 66 of the dial 65 results from the geometric dimensions of the valve chamber 16, in particular the height between the end 4 to the valve seat 41 and the height of the sealing sleeve 19. It is essential that in the open position of the valve pin 20, in the actuated actuator 55 the bottom 61 of the valve pin 20 rests on the top of the dial 65, between the compression spring 30 facing underside of the transfer body 35 and the guide member 29 still a gap 67 remains.

Besonders vorteilhaft ist es, zumindest eine Kontaktfläche zwischen dem Ventilbolzen 20 und der Einstellscheibe 65 und/oder zwischen der Einstellscheibe 65 und der Dichthülse 19 mit mindestens einer radial umlaufenden Nut zu versehen, die in der Darstellung der Fig. 1 nicht erkennbar ist. Auf diese Weise wird erreicht, dass auch bei geöffnetem Steuerventil 15, also bei an seinem Hubanschlag befindlichen Ventilbolzen 20, das ventilraumseitige Ende des Kraftstoffspalts 48 hydraulisch mit dem Ventilraum 16 verbunden ist. Auf diese Weise wird ein hydraulisches Kleben zwischen dem Ventilbolzen 20 und der Dichthülse 19 vermieden.It is particularly advantageous to provide at least one contact surface between the valve pin 20 and the adjusting disk 65 and / or between the adjusting disk 65 and the sealing sleeve 19 with at least one radially circumferential groove, which in the illustration of Fig. 1 is not recognizable. In this way it is achieved that even with the control valve 15 open, that is located at its stroke stop valve pin 20, the valve-chamber-side end of the fuel gap 48 is hydraulically connected to the valve chamber 16. In this way, a hydraulic bonding between the valve pin 20 and the sealing sleeve 19 is avoided.

Bei dem in der Fig. 2 dargestellten Kraftstoffinjektor 1a weist das Führungselement 29a lediglich ein Federaufnahmeelement 33a, jedoch keinen Führungsabschnitt 31 entsprechend dem Kraftstoffinjektor 1 auf.In the in the Fig. 2 shown fuel injector 1a, the guide member 29a only a spring receiving element 33a, but no guide portion 31 corresponding to the fuel injector 1.

Bei dem in der Fig. 3 dargestellten Kraftstoffinjektor 1 b ist im Gegensatz zum Kraftstoffinjektor 1 innerhalb des druckentlasteten Raums 27 kein Führungselement 29 vorgesehen. Vielmehr stützt sich die Druckfeder 30 zwischen dem Übertragungskörper 35 und dem Grund 32 des druckentlasteten Raums 27 ab.In the in the Fig. 3 shown fuel injector 1 b, in contrast to the fuel injector 1 within the pressure-relieved space 27, no guide member 29 is provided. Rather, the compression spring 30 is supported between the transfer body 35 and the bottom 32 of the pressure-relieved space 27.

Die soweit beschriebenen Kraftstoffinjektoren 1, 1a und 1b können in vielfältiger Art und Weise abgewandelt bzw. modifiziert werden. Dieser besteht darin, den Hubanschlag für den Ventilbolzen 20 in seiner Öffnungsstellung durch eine entsprechende Dimensionierung der Dichthülse 19, insbesondere jedoch durch die Dimensionierung einer Einstellscheibe 65 einzustellen, die zwischen der Dichthülse 19 und der Drosselplatte 2 bzw. dem druckentlasteten Raum 27 angeordnet ist. So liegt es auch im Rahmen der Erfindung, auf die Einstellscheibe 65 zu verzichten, und die Hubbegrenzung des Ventilbolzens 20 durch eine entsprechend genaue Fertigung der Länge bzw. Höhe der Dichthülse 19 auszubilden. Weiterhin können die Kontaktflächen zwischen der Dichthülse 19 und der Einstellscheibe 65 und/oder zwischen der Einstellscheibe 65 und dem Ventilbolzen 20 jeweils plan oder konisch ausgebildet sein. Die Kegelwinkel können dabei jeweils derart gewählt sein, dass sich eine echte Kontaktfläche ausbildet, aber auch derart, dass sich eine Kontaktline ausbildet.The fuel injectors 1, 1a and 1b described so far can be modified or modified in a variety of ways. This is to adjust the stroke stop for the valve pin 20 in its open position by a corresponding dimensioning of the sealing sleeve 19, but in particular by the dimensioning of a dial 65 which is disposed between the sealing sleeve 19 and the throttle plate 2 and the pressure-relieved space 27. So it is also within the scope of the invention to dispense with the dial 65, and form the stroke limiter of the valve pin 20 by a correspondingly accurate production of the length or height of the sealing sleeve 19. Furthermore, the contact surfaces between the sealing sleeve 19 and the shim 65 and / or between the shim 65 and the valve pin 20 may each be flat or conical. The cone angles can each be selected such that a true contact surface is formed, but also in such a way that a contact line is formed.

Claims (11)

  1. Fuel injector (1; 1a; 1b), in particular for compression-ignition internal combustion engines, with a control valve (15) and a control chamber (8), wherein the control chamber (8) is connected via an outlet bore (25) to a valve chamber (16) of the control valve (15), wherein a valve bolt (20) is arranged in the valve chamber (16), wherein the valve bolt (20) is loaded by the spring force of a compression spring (30) in a first position into a closing position in which said valve bolt interacts with a valve seat surface (41), wherein the compression spring (30) is arranged in a low-pressure region (27) which is sealed in relation to the valve chamber (16), wherein the opening stroke of the valve bolt (20) can be set for a second position, in which the valve bolt (20) is spaced apart from the valve seat surface (41), and wherein the valve bolt (20) is guided in the valve chamber (16) by a sealing sleeve (19) which radially encloses the valve bolt (20),
    characterized
    in that the opening stroke of the valve bolt (20) is brought about by the valve bolt (20) at least indirectly bearing against the sealing sleeve (19).
  2. Fuel injector according to Claim 1,
    characterized
    in that the stroke is limited by means of a setting disc (65) which is arranged in the valve chamber (16).
  3. Fuel injector according to Claim 2,
    characterized
    in that the setting disc (65) is arranged on that side of the sealing sleeve (19) which faces the valve seat surface (41) and, in order to form the stroke stop, interacts with a diameter-enlarged portion (60) of the valve bolt (20).
  4. Fuel injector according to one of Claims 1 to 3,
    characterized
    in that a preferably disc-shaped transmission body (35) is arranged in the low-pressure region (27) between the compression spring (30) and the valve bolt (20), which transmission body (35) under loading by the spring force of the compression spring (30) bears against that end side of the valve bolt (20) which faces away from the valve seat surface (41).
  5. Fuel injector according to one of Claims 1 to 4,
    characterized
    in that the sealing sleeve (19) has, on the side facing the compression spring (30), a biting edge (38) which bears in a sealing manner against an end surface (18) of the valve chamber (16).
  6. Fuel injector according to one of Claims 1 to 5,
    characterized
    in that the compression spring (30) bears against a spring support element (33; 33a) on the side facing away from the valve bolt (20).
  7. Fuel injector according to Claim 6,
    characterized
    in that the spring support element (33) is part of a guide element (29) which has a preferably pin- shaped guide portion (31) which is radially enclosed by the compression spring (30).
  8. Fuel injector according to Claim 6 or 7,
    characterized
    in that the spring support element (33; 33a) has a radially encircling bevel (34) on the side facing away from the compression spring (30).
  9. Fuel injector according to one of Claims 1 to 8,
    characterized
    in that the low-pressure chamber (27) is designed as a blind hole and has a rounded edge (36) on the base (32) thereof.
  10. Fuel injector according to one of Claims 2 to 9,
    characterized
    in that at least one groove extending in the radial direction is formed at least on one of the contact surfaces between the valve bolt (20) and the setting disc (65), between the setting disc (65) and the sealing sleeve (19) or between the valve bolt (20) and the sealing sleeve (19), and in that the groove hydraulically connects the valve chamber (16) and the valve-chamber-side end of the guide gap between the sealing sleeve (19) and the valve bolt (20) to each other.
  11. Fuel injector according to one of Claims 1 to 10,
    characterized
    in that a diameter (52) of a sealing seat (42) between the valve bolt (20) and the valve seat surface (41) is larger than a diameter (51) of a guide bore (22) of the sealing sleeve (19), in which the valve bolt (20) is guided.
EP12723454.0A 2011-06-30 2012-05-23 Fuel injector Active EP2726731B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE201110078400 DE102011078400A1 (en) 2011-06-30 2011-06-30 fuel injector
PCT/EP2012/059532 WO2013000635A1 (en) 2011-06-30 2012-05-23 Fuel injector

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EP2726731A1 EP2726731A1 (en) 2014-05-07
EP2726731B1 true EP2726731B1 (en) 2015-07-08

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Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19618698A1 (en) * 1996-05-09 1997-11-13 Bosch Gmbh Robert Fuel injection valve for internal combustion engines
DE102004046191B3 (en) * 2004-09-23 2006-04-13 Siemens Ag Servo valve and injector
DE102007035698A1 (en) * 2007-07-30 2009-02-05 Robert Bosch Gmbh Fuel injection valve with improved tightness at the sealing seat of a pressure-balanced control valve
DE102009002742A1 (en) * 2009-04-30 2010-11-04 Robert Bosch Gmbh Fuel injector for injecting fuel into combustion chamber of internal-combustion engine, particularly common rail injector, comprises single or multipart injection valve element for opening and closing injection opening
DE102010040874A1 (en) * 2010-09-16 2012-03-22 Robert Bosch Gmbh Fuel injector
DE102010063540A1 (en) 2010-12-20 2012-06-21 Robert Bosch Gmbh Brennstoffeinspitzventil

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DE102011078400A1 (en) 2013-01-03
WO2013000635A1 (en) 2013-01-03
EP2726731A1 (en) 2014-05-07
CN103635686A (en) 2014-03-12

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