EP1843038B1 - Fuel injector with a conical high pressure housing sealing - Google Patents

Fuel injector with a conical high pressure housing sealing Download PDF

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Publication number
EP1843038B1
EP1843038B1 EP06007432A EP06007432A EP1843038B1 EP 1843038 B1 EP1843038 B1 EP 1843038B1 EP 06007432 A EP06007432 A EP 06007432A EP 06007432 A EP06007432 A EP 06007432A EP 1843038 B1 EP1843038 B1 EP 1843038B1
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EP
European Patent Office
Prior art keywords
fuel injector
housing
pressure
embodied
nozzle
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
EP06007432A
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German (de)
French (fr)
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EP1843038A1 (en
Inventor
Jürgen Dick
Hellmut Freudenberg
Walter Dr. Meindl
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.)
Continental Automotive GmbH
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Continental Automotive GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Continental Automotive GmbH filed Critical Continental Automotive GmbH
Priority to EP06007432A priority Critical patent/EP1843038B1/en
Priority to DE502006003182T priority patent/DE502006003182D1/en
Publication of EP1843038A1 publication Critical patent/EP1843038A1/en
Application granted granted Critical
Publication of EP1843038B1 publication Critical patent/EP1843038B1/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

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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
    • F02M63/0014—Valves characterised by the valve actuating means
    • F02M63/0015—Valves characterised by the valve actuating means electrical, e.g. using solenoid
    • F02M63/0026—Valves characterised by the valve actuating means electrical, e.g. using solenoid using piezoelectric or magnetostrictive actuators
    • 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
    • F02M51/00—Fuel-injection apparatus characterised by being operated electrically
    • F02M51/06—Injectors peculiar thereto with means directly operating the valve needle
    • F02M51/0603—Injectors peculiar thereto with means directly operating the valve needle using piezoelectric or magnetostrictive operating means
    • 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
    • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
    • 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
    • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
    • F02M61/168—Assembling; Disassembling; Manufacturing; Adjusting
    • 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
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/16—Sealing of fuel injection apparatus not otherwise provided for
    • 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
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/70—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger
    • F02M2200/701—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger mechanical
    • F02M2200/702—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger mechanical with actuator and actuated element moving in different directions, e.g. in opposite directions
    • 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
    • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
    • F02M61/167—Means for compensating clearance or thermal expansion

Definitions

  • the invention relates to a fuel injector having at least two cylindrical housing parts, which are joined together by means of a nozzle lock nut, according to the preamble of the main claim.
  • a fuel injector has a plurality of subassemblies which are assembled axially one above the other.
  • Such assemblies may be, for example, an injector housing and a nozzle housing held together by a nozzle lock nut.
  • the nozzle retaining nut is pushed over the nozzle housing as a union nut and firmly screwed to the injector housing.
  • the end faces of the two opposing housing parts are designed as sealing surfaces and are pressed together by the clamping force of the nozzle retaining nut.
  • a high pressure space e.g. Having fuel supply lines and / or pressure accumulator, formed, which is filled with fuel and in a diesel fuel injector of a common rail system may have a pressure of up to 2000 bar. Against this high pressure no leakage may occur at the end faces of the two assembled housing parts.
  • a piezoelectric injector with a directly driven register nozzle needle for fuel injection in an internal combustion engine is known.
  • the two nozzle needles of Registerdüsennadel are not operated to open the injection holes as usual via a servo valve or constructed in the injector fuel pressure, but directly from the piezoelectric actuator.
  • a fuel injection valve for internal combustion engines has a valve body, in which a valve member is guided axially displaceable and which is biased by a clamping nut axially against a valve holding body. Between the valve body and the valve holding body, an intermediate disc is clamped, which rests with its sealing surfaces sealingly against the axial end faces of the valve body and valve holding body. For a uniform introduction of force at the cross section between the washer and the valve body, at least one of the cooperating end faces on the valve body and on the intermediate disc is structurally curved outward.
  • an injection valve which has at the nozzle tip a nozzle sleeve which is biased by a threaded sleeve against the housing of the injection valve. Between the housing and the nozzle sleeve sealing surfaces are arranged, which are arranged at a fixed angle obliquely to the longitudinal axis of the injection valve.
  • an injection valve which is connected via a coupling piece with a fuel line. Between the coupling piece and the housing of the injection valve, a sealing surface is arranged, which is aligned at a fixed angle obliquely to the longitudinal axis of the injection valve.
  • the invention has for its object to improve in a fuel injector, the high-pressure tightness of two abutting sealing surfaces of two housing parts. This object is achieved with the characterizing feature of the main claim.
  • the two abutting sealing surfaces of the two housing parts are formed conically.
  • the two sealing surfaces of the two housing parts are thus not manufactured at an angle to the longitudinal axis, but with a predetermined cone angle.
  • a secure centering of the two housing parts can be achieved in an advantageous manner.
  • the two housing parts are placed on each other with the help of the cone and pressed firmly together by the high torque of the nozzle lock nut.
  • the upper housing has a softer material or a thinner wall thickness than the lower housing part, then the upper housing part will expand somewhat more than the lower housing part when there is a pressure increase inside the fuel injector in the radial direction.
  • both housing parts Due to the high biasing force of the nozzle lock nut, however, both housing parts are fixed in this position so that their relative position to one another no longer shift after the high pressure has dropped can. This ensures that no relative displacement can occur between the two sealing surfaces of the two housing parts.
  • the high-pressure seal is therefore wear-free and reliable high-pressure-tight.
  • the sealing surfaces are formed rounded one another.
  • the two superimposed sealing surfaces are conical with a predetermined cone angle or convex / concave preferably with a predetermined radius flush with each other, the frusto-conical sealing surfaces are inclined by a few degrees to each other or that the convex / concave sealing surfaces such a slightly different radius have that in a ring-shaped sealing region, the sealing effect is increased.
  • conical sealing surfaces can be easily formed on any housing parts.
  • a reliable high-pressure seal can also be achieved in this way between the injector housing and a further module, for example in the case of an inserted housing plate for the lever translator.
  • the high-pressure seal can be carried out in particular in a fuel injector, which has no leakage oil return.
  • a fuel injector which has no leakage oil return.
  • the high-pressure space in the interior of the fuel injector is made relatively large, so that the high-pressure seal is also exposed to particularly high loads.
  • Another aspect of the invention is that in the construction and in the design of the fuel injector it is no longer necessary to pay close attention to the fact that the wall thicknesses in the high-pressure region are the same as possible for you and for the material involved. This results in a much greater latitude for the designer in the design of the injector design.
  • FIG. 1 shows a detail of a longitudinal section through a fuel injector 1.
  • the fuel injector 1 is part of a common rail injection system, which is particularly suitable for diesel engines or gasoline engines.
  • the fuel injector 1 is formed without leakage oil return.
  • the fuel injector 1 is applicable to all types of fuel injectors.
  • a piezoelectric actuator 3 is arranged in the upper part of the FIG. 1 such that upon electrical excitation, its bottom plate can expand downwardly, while its top plate (in FIG. 1 not shown) is firmly connected to an injector 2. If the excitation voltage is switched off, then the lower part of the piezoelectric actuator 3 retracts back to its original position.
  • a hydraulic longitudinal compensation 10 is arranged in the central bore of the further below the bottom plate of the piezoelectric actuator 3.
  • the hydraulic longitudinal compensation 10 causes changes in length of the actuator as a result of temperature changes, aging, wear, etc. are compensated automatically by hydraulic means, so that always the full stroke of the piezoelectric actuator 3 is available.
  • the hydraulic longitudinal compensation 10 is pressed by means of a compression spring 11, which is supported at its upper end against the injector 2, down.
  • a lever translator 15 is arranged such that the change in length of the piezoelectric actuator 3 can be transmitted to the lever translator 15.
  • the lever translator 15 has two essential tasks to fulfill.
  • the hydraulic lever translator 15 is intended to increase the stroke of the piezoelectric actuator 3, which is usually of the order of magnitude of 50 to 80 ⁇ m. As a result, the opening travel of a nozzle needle 7 can be increased.
  • a second task for the lever translator 15 is also that the lever translator 15 is simultaneously designed as a Hubumnovaer.
  • the Hubumrocker causes the downward length alignment of the piezoelectric actuator 3 is converted into a lifting movement for the nozzle needle 7, which is directed upward.
  • the lever translator 15 is essentially a pressure lever 19, to which the pressure force of the piezoelectric actuator 3 by means of the hydraulic longitudinal compensation 10 can be transmitted.
  • the pressure lever 19 is arranged transversely in the central bore of the actuator housing 2.
  • the pressure lever 19 is supported with its right part on a fixed support block 14.
  • the fixed support block 14 is formed angularly, with its free leg engages in a groove of a nozzle needle 7, which at the shaft of the nozzle needle 7 slightly below the The head is arranged in a ring shape.
  • the free leg of the support block 14 is at the top of the groove of the nozzle needle 7 at.
  • the left part of the pressure lever 19 is designed to be movable. Below the left part of the pressure lever 19, a rocker arm 16 is arranged, which is in operative connection with the movable part of the pressure lever 19. The rocker arm 16 is guided with its free leg into the groove of the nozzle needle 7 and designed such that the nozzle needle 7 is lifted from its valve seat when the piezoelectric actuator 3 is actuated while the pressure lever 19 presses on the rocker arm 16.
  • a housing part 5 is arranged below the lever translator 15, a housing part 5 is arranged.
  • the lower end of the nozzle housing 6 is formed with spray holes which are opened when the piezoelectric actuator 3 is actuated or closed when the activation is switched off (in FIG FIG. 1 not shown).
  • a nozzle needle spring 13 is additionally arranged coaxially around the nozzle needle 7, which on the one hand against a lower end face of the housing part 5 and with its second end against a pressure surface of the nozzle needle. 7 supports and presses the nozzle needle 7 in the direction of its valve seat down.
  • the nozzle housing 6, the housing part 5 arranged above it and the injector housing 2 are held together with a nozzle retaining nut 4, wherein the nozzle retaining nut 4 is guided from below over the nozzle housing 6 and is firmly screwed to an external thread of the injector housing 2.
  • the housing part 5 is formed as a housing plate.
  • the housing part may be formed, for example, as a needle guide body or the like.
  • a high-pressure chamber 9 is formed, which is filled with fuel, diesel oil or gasoline.
  • the high pressure in the high pressure chamber 9 is by a pressure pump of the common rail injection system (in FIG. 1 not shown), wherein the fuel from the high pressure pump via corresponding channels of the fuel injector 1 to the high pressure chamber 9 and on to the nozzle tip of the nozzle housing 6 is performed.
  • the high-pressure chamber is limited on the one hand to the outside through the wall of the cylinder-shaped injector 2 upwards. At the bottom, the high-pressure chamber is bounded on the one hand by the shaft of the nozzle needle 7. Furthermore, there is a lateral boundary of the high-pressure chamber 9 through the wall of the cylinder-shaped housing part. 5
  • the lower end face of the fuel injector 2 which rests on the upper end face of the housing part 5, formed as a high-pressure seal 12. Since there is a fuel pressure inside the high-pressure chamber 9, in particular in the case of a diesel injector of up to 2000 bar, this high-pressure seal 12 must be designed to be particularly reliable and safe. In particular, it must be ensured that the high-pressure seal 12 is wear-free and durable, in particular if the wall thicknesses of the two assembled housing parts 2.5 are different degrees or if different rigid materials are used.
  • the wall thickness of the injector 2 is formed thinner than that of the housing part 5.
  • FIG. 2 shows a section with the high pressure seal 12, as shown in the longitudinal section of FIG. 1 on the right side is shown.
  • the wall thickness d1 of the injector housing 2 is smaller than the wall thickness d2 of the housing part 5.
  • Both housing parts 2, 5 are compressed by the nozzle lock nut 4 on the upper sealing surface 8a of the injector housing 2 and the lower sealing surface 8b of the housing part 5 by the bias of the nozzle lock nut 4.
  • FIG. 2 shows a section with the high pressure seal 12, as shown in the longitudinal section of FIG. 1 on the right side is shown.
  • the wall thickness d1 of the injector housing 2 is smaller than the wall thickness d2 of the housing part 5.
  • Both housing parts 2, 5 are compressed by the nozzle lock nut 4 on the upper sealing surface 8a of the injector housing 2 and the lower sealing surface 8b of the housing part 5 by the bias of the nozzle lock nut 4.
  • the two pressure surfaces 8a, 8b are formed conically with a cone angle ⁇ .
  • the conical or rounded design of the high pressure seal 12 is one aspect of the invention.
  • the cone angle ⁇ is formed so that the component with the thinner wall thickness or the weaker stiffness can not withstand pressure relief. As in the Figures 1 and 2 is shown, the cone angle ⁇ is formed leading downward. As a result, the injector housing 2 with the smaller wall thickness d1 can expand outward when the pressure rises, thereby sliding on the sealing surfaces 8a, 8b. Due to the high clamping force P v of the nozzle retaining nut 4, the two sealing surfaces 8a, 8b of the two housing parts 2, 5 are fixed in this position.
  • the clamping force P v of the nozzle lock nut 4 continues to act in the axial direction to the fuel injector 1 on the two sealing surfaces 8 a, 8 b.
  • the cone angle ⁇ prevents a stronger contraction of the wall of the injector housing 2 in the still existing clamping force P v of the nozzle retaining nut 4.
  • the result is that the high-pressure seal 12 is completely free of wear and reliably sealed high pressure-tight. Even with aging or temperature changes, a shift of the two sealing surfaces, 8a, 8b to each other can not form.
  • the cone angle ⁇ is preferably formed depending on the application and the prevailing fuel pressure between 10 and 20 °.
  • FIG. 3 shows an alternative embodiment of the sealing surfaces 8a, 8b FIG. 2 with rounded sealing surfaces 8a ', 8b'.
  • the concave sealing surface 8a ' is flush with the convex sealing surface 8b'.
  • the radius of the convex sealing surface 8b ' is slightly smaller than the radius of the concave sealing surface 8a', so that the better tighten the sealing surfaces and a sealing ring with increased surface pressure arises.

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

Description

Die Erfindung betrifft einen Kraftstoffinjektor, der wenigstens zwei zylinderförmige Gehäuseteile aufweist, die mittels einer Düsenspannmutter zusammengefügt sind, nach der Gattung des Hauptanspruchs. Es ist bereits bekannt, dass ein Kraftstoffinjektor mehrere Baugruppen aufweist, die axial übereinander liegend zusammengefügt sind. Solche Baugruppen können beispielsweise ein Injektorgehäuse und ein Düsengehäuse sein, die durch eine Düsenspannmutter zusammengehalten werden. Dabei wird in der Regel die Düsenspannmutter als Überwurfmutter über das Düsengehäuse geschoben und mit dem Injektorgehäuse fest verschraubt. Die Stirnflächen der beiden sich gegenüber liegenden Gehäuseteile sind als Dichtflächen ausgebildet und werden durch die Spannkraft der Düsenspannmutter zusammengepresst. Im Inneren des Kraftstoffinjektors ist ein Hochdruckraum, z.B. Kraftstoffzulaufleitungen und/oder Druckspeicher aufweisend, ausgebildet, der mit Kraftstoff gefüllt ist und bei einem Diesel-Kraftstoffinjektor eines Common-Rail-Systems einen Druck von bis zu 2000 bar aufweisen kann. Gegen diesen hohen Druck darf an den Stirnflächen der beiden zusammengefügten Gehäuseteile keine Undichtheit auftreten.The invention relates to a fuel injector having at least two cylindrical housing parts, which are joined together by means of a nozzle lock nut, according to the preamble of the main claim. It is already known that a fuel injector has a plurality of subassemblies which are assembled axially one above the other. Such assemblies may be, for example, an injector housing and a nozzle housing held together by a nozzle lock nut. As a rule, the nozzle retaining nut is pushed over the nozzle housing as a union nut and firmly screwed to the injector housing. The end faces of the two opposing housing parts are designed as sealing surfaces and are pressed together by the clamping force of the nozzle retaining nut. Inside the fuel injector is a high pressure space, e.g. Having fuel supply lines and / or pressure accumulator, formed, which is filled with fuel and in a diesel fuel injector of a common rail system may have a pressure of up to 2000 bar. Against this high pressure no leakage may occur at the end faces of the two assembled housing parts.

Bisher wurde dieses Problem dadurch gelöst, dass die Stirnflächen der beiden zusammenzufügenden Gehäuseteile winkelig und planparallel ausgeführt wurden. Es hat sich jedoch herausgestellt, dass sich insbesondere bei unterschiedlich dicken Gehäusewandungen oder einer ungleichen Materialsteifigkeit der beiden Gehäuseteile relative Verschiebungen an den Stirnflächen beziehungsweise an den Dichtflächen ergeben können. Die unterschiedlichen Verschiebungen entstehen durch eine unterschiedliche radiale Maerialausdehnung, insbesondere wenn im Hochdruckraum Druckänderungen auftreten.So far, this problem has been solved by the fact that the end faces of the two parts to be joined together were performed angular and plane-parallel. However, it has been found that relative displacements on the end faces or on the sealing surfaces can result, in particular in the case of housing walls of different thicknesses or an uneven material rigidity of the two housing parts. The different shifts are caused by a different radial Maerialausdehnung, especially when pressure changes occur in the high pressure chamber.

Bisher wurde dieses Problem dadurch gelöst, dass die Wandstärken im Bereich der Hochdruckdichtung möglichst gleich stark gewählt wurden. Des weiteren wurde für jedes Gehäuseteil ein Material mit gleicher Steifigkeit verwendet, damit keine relativen radialen Ausdehnungen an den Stirnflächen der sich gegenüberliegenden Gehäuseteile entstehen können. Allerdings ergibt sich dabei der Nachteil, dass durch die zuvor genannten Bedingungen die Konstruktion des Kraftstoffinjektors in seinem Design beeinträchtigt wirdSo far, this problem has been solved in that the wall thicknesses in the area of the high-pressure seal have been selected as equally strong. Furthermore, a material with the same rigidity was used for each housing part, so that no relative radial expansions can occur on the end faces of the opposite housing parts. However, this results in the disadvantage that the construction of the fuel injector is impaired in its design by the aforementioned conditions

Aus WO 2004/046540 A1 ist ein piezoelektrischer Injektor mit einer direkt angetriebenen Register-Düsennadel zur Kraftstoffeinspritzung in einem Verbrennungsmotor bekannt. Die beiden Düsennadeln der Registerdüsennadel werden zur Öffnung der Spritzlöcher nicht wie sonst üblich über ein Servoventil oder den im Injektor aufgebauten Kraftstoffdruck betätigt, sondern direkt von dem piezoelektrischen Aktor.Out WO 2004/046540 A1 For example, a piezoelectric injector with a directly driven register nozzle needle for fuel injection in an internal combustion engine is known. The two nozzle needles of Registerdüsennadel are not operated to open the injection holes as usual via a servo valve or constructed in the injector fuel pressure, but directly from the piezoelectric actuator.

Aus DE 196 08 575 A1 ist ein Kraftstoffeinspritzventil für Brennkraftmaschinen bekannt. Das Kraftstoffeinspritzventil weist einen Ventilkörper auf, in dem ein Ventilglied axial verschiebbar geführt ist und der mittels einer Spannmutter axial gegen einen Ventilhaltekörper vorgespannt ist. Zwischen dem Ventilkörper und dem Ventilhaltekörper ist eine Zwischenscheibe eingespannt, die mit ihren Dichtflächen dichtend an den axialen Stirnflächen des Ventilkörpers und Ventilhaltekörpers anliegt. Für eine gleichmäßige Krafteinleitung am Querschnitt zwischen der Zwischenscheibe und dem Ventilkörper ist wenigstens eine der zusammen wirkenden Stirnflächen am Ventilkörper und an der Zwischenscheibe baulich nach außen gewölbt.Out DE 196 08 575 A1 a fuel injection valve for internal combustion engines is known. The fuel injection valve has a valve body, in which a valve member is guided axially displaceable and which is biased by a clamping nut axially against a valve holding body. Between the valve body and the valve holding body, an intermediate disc is clamped, which rests with its sealing surfaces sealingly against the axial end faces of the valve body and valve holding body. For a uniform introduction of force at the cross section between the washer and the valve body, at least one of the cooperating end faces on the valve body and on the intermediate disc is structurally curved outward.

Aus US 1,692,107 A ist ein Einspritzventil bekannt, das an der Düsenspitze eine Düsenhülse aufweist, die über eine Schraubhülse gegen das Gehäuse des Einspritzventils vorgespannt ist. Zwischen dem Gehäuse und der Düsenhülse sind Dichtflächen angeordnet, die in einem festen Winkel schräg zur Längsachse des Einspritzventils angeordnet sind.Out US 1,692,107 A an injection valve is known, which has at the nozzle tip a nozzle sleeve which is biased by a threaded sleeve against the housing of the injection valve. Between the housing and the nozzle sleeve sealing surfaces are arranged, which are arranged at a fixed angle obliquely to the longitudinal axis of the injection valve.

Aus EP 1 619 383 A2 ist ein Einspritzventil bekannt, das über ein Kopplungsstück mit einer Kraftstoffleitung verbunden ist. Zwischen dem Kopplungsstück und dem Gehäuse des Einspritzventils ist eine Dichtfläche angeordnet, die in einem festgelegten Winkel schräg zur Längsachse des Einspritzventils ausgerichtet ist.Out EP 1 619 383 A2 an injection valve is known, which is connected via a coupling piece with a fuel line. Between the coupling piece and the housing of the injection valve, a sealing surface is arranged, which is aligned at a fixed angle obliquely to the longitudinal axis of the injection valve.

Der Erfindung liegt die Aufgabe zugrunde, bei einem Kraftstoffinjektor die Hochdruckdichtheit an zwei aneinander stoßenden Dichtflächen zweier Gehäuseteile zu verbessern. Diese Aufgabe wird mit dem kennzeichnenden Merkmal des Hauptanspruchs gelöst.The invention has for its object to improve in a fuel injector, the high-pressure tightness of two abutting sealing surfaces of two housing parts. This object is achieved with the characterizing feature of the main claim.

Ein wesentlicher Aspekt der Erfindung wird darin gesehen, dass die beiden aneinander stoßenden Dichtflächen der beiden Gehäuseteile kegelig ausgebildet sind. Die beiden Dichtflächen der beiden Gehäuseteile werden somit nicht winklig zur Längsachse gefertigt, sondern mit einem vorgegebenen Kegelwinkel. Dadurch kann in vorteilhafter Weise einerseits eine sichere Zentrierung der beiden Gehäuseteile erzielt werden. Andererseits werden die beiden Gehäuseteile mit Hilfe der Kegel aufeinander gesetzt und durch das hohe Anzugsmoment der Düsenspannmutter fest aufeinandergepresst. Wenn zum Beispiel das obere Gehäuse ein weicheres Material oder eine dünnere Wandstärke aufweist als das untere Gehäuseteil, dann wird sich das obere Gehäuseteil bei einem Druckanstieg im Innern des Kraftstoffinjektors in radialer Richtung etwas stärker ausdehnen als das untere Gehäuseteil. Durch die hohe Vorspannkraft der Düsenspannmutter werden beide Gehäuseteile jedoch in dieser Position fixiert, so dass sich deren relative Position zueinander nach Abfall des Hochdrucks nicht mehr verschieben kann. Dadurch ist gewährleistet, dass zwischen den beiden Dichtflächen des beiden Gehäuseteile keine relative Verschiebung entstehen kann. Die Hochdruckdichtung ist daher verschleißfrei und zuverlässig hochdruckdicht. Alternativ sind die Dichtflächen gerundet aufeinander liegend ausgebildet. Erfindungsgemäß sind die beiden aufeinander liegenden Dichtflächen konisch mit einem vorgegebenen Kegelwinkel oder konvex/konkav vorzugsweise mit einem vorgegebenen Radius bündig aneinander liegend, wobei die kegelstumpfförmigen Dichtflächen um wenige Grad so zueinander geneigt sind oder dass die konvex/konkav ausgebildeten Dichtflächen einen so leicht voneinander abweichenden Radius aufweisen, dass in einem ringförmigen Dichtbereich die Dichtwirkung erhöht ist.An essential aspect of the invention is seen in that the two abutting sealing surfaces of the two housing parts are formed conically. The two sealing surfaces of the two housing parts are thus not manufactured at an angle to the longitudinal axis, but with a predetermined cone angle. As a result, on the one hand a secure centering of the two housing parts can be achieved in an advantageous manner. On the other hand, the two housing parts are placed on each other with the help of the cone and pressed firmly together by the high torque of the nozzle lock nut. For example, if the upper housing has a softer material or a thinner wall thickness than the lower housing part, then the upper housing part will expand somewhat more than the lower housing part when there is a pressure increase inside the fuel injector in the radial direction. Due to the high biasing force of the nozzle lock nut, however, both housing parts are fixed in this position so that their relative position to one another no longer shift after the high pressure has dropped can. This ensures that no relative displacement can occur between the two sealing surfaces of the two housing parts. The high-pressure seal is therefore wear-free and reliable high-pressure-tight. Alternatively, the sealing surfaces are formed rounded one another. According to the two superimposed sealing surfaces are conical with a predetermined cone angle or convex / concave preferably with a predetermined radius flush with each other, the frusto-conical sealing surfaces are inclined by a few degrees to each other or that the convex / concave sealing surfaces such a slightly different radius have that in a ring-shaped sealing region, the sealing effect is increased.

Durch die in den abhängigen Ansprüchen aufgeführten Maßnahmen sind vorteilhafte Weiterbildungen und Verbesserungen des im Hauptanspruch angegebenen Kraftstoffinjektors gegeben. Als besonders vorteilhaft wird dabei angesehen, dass der Kegelwinkel so ausgebildet ist, dass in Verbindung mit der Vorspannkraft die beiden Dichtflächen sicher fixiert sind.The measures listed in the dependent claims advantageous refinements and improvements of the main claim fuel injector are given. Particularly advantageous is considered that the cone angle is formed so that in connection with the biasing force, the two sealing surfaces are securely fixed.

Ein weiterer Aspekt der Erfindung ist, dass die kegeligen Dichtflächen an beliebigen Gehäuseteilen sehr einfach ausgebildet werden können. Insbesondere kann auf diese Weise auch zwischen dem Injektorgehäuse und einer weiteren Baugruppe, beispielsweise bei einer eingefügten Gehäuseplatte für den Hebelübersetzer eine zuverlässige Hochdruckdichtung erreicht werden.Another aspect of the invention is that the conical sealing surfaces can be easily formed on any housing parts. In particular, a reliable high-pressure seal can also be achieved in this way between the injector housing and a further module, for example in the case of an inserted housing plate for the lever translator.

Ein weiterer Vorteil der Erfindung wird auch darin gesehen, dass die Hochdruckdichtung insbesondere bei einem Kraftstoffinjektor durchführbar ist, der keinen Leckölrücklauf aufweist. Bei einem solchen Kraftstoffinjektor ist der Hochdruckraum im Innern des Kraftstoffinjektors verhältnismäßig groß ausgebildet ist, so dass auch die Hochdruckdichtung besonders starken Belastungen ausgesetzt ist.Another advantage of the invention is also seen in the fact that the high-pressure seal can be carried out in particular in a fuel injector, which has no leakage oil return. In such a fuel injector, the high-pressure space in the interior of the fuel injector is made relatively large, so that the high-pressure seal is also exposed to particularly high loads.

Ein weiterer Aspekt der Erfindung besteht darin, dass bei der Konstruktion und im Design des Kraftstoffinjektors nicht mehr so gründlich darauf geachtet werden muss, dass die Wandstärken im Hochdruckbereich für die beteiligten Gehäuseteile möglichst exakt gleich dich und bezüglich des Materials gleichartig ausgebildet sind. Dadurch ergibt sich für den Konstrukteur ein wesentlich größerer Spielraum bei der Auslegung des Injektordesigns.Another aspect of the invention is that in the construction and in the design of the fuel injector it is no longer necessary to pay close attention to the fact that the wall thicknesses in the high-pressure region are the same as possible for you and for the material involved. This results in a much greater latitude for the designer in the design of the injector design.

Ein Ausführungsbeispiel der Erfindung ist in der Zeichnung dargestellt und wird in der nachfolgenden Beschreibung näher erläutert.

  • Figur 1 zeigt ausschnittsweise einen Längsschnitt eines Kraftstoffinjektors und
  • Figur 2 zeigt ausschnittsweise ein Detailbild einer Hochdruckdichtfläche.
  • Figur 3 zeigt eine alternative Ausformung der Dichtflächen aus Figur 2.
An embodiment of the invention is illustrated in the drawing and will be explained in more detail in the following description.
  • FIG. 1 shows a detail of a longitudinal section of a fuel injector and
  • FIG. 2 shows a detail of a detail of a high-pressure sealing surface.
  • FIG. 3 shows an alternative shape of the sealing surfaces FIG. 2 ,

Figur 1 zeigt ausschnittsweise einen Längsschnitt durch einen Kraftstoffinjektor 1. Der Kraftstoffinjektor 1 ist Teil eines Common-Rail-Einspritzsystems, das insbesondere für Dieselmotoren oder Benzinmotoren verwendbar ist. In einer besonderen Ausführungsform ist der Kraftstoffinjektor 1 ohne Leckölrücklauf ausgebildet. In alternativer Ausführungsform der Erfindung ist vorgesehen, dass der Kraftstoffinjektor 1 für alle Arten von Kraftstoffinjektoren anwendbar ist. FIG. 1 shows a detail of a longitudinal section through a fuel injector 1. The fuel injector 1 is part of a common rail injection system, which is particularly suitable for diesel engines or gasoline engines. In a particular embodiment, the fuel injector 1 is formed without leakage oil return. In an alternative embodiment of the invention it is provided that the fuel injector 1 is applicable to all types of fuel injectors.

Wie aus der Figur 1 weiter entnehmbar ist, ist im oberen Teil der Figur 1 ein piezoelektrischer Aktor 3 angeordnet. Der piezoelektrische Aktor 3 ist in einer zentralen Bohrung des Kraftstoffinjektors 1 derart angeordnet, dass bei elektrischer Erregung sich seine Bodenplatte nach unten hin ausdehnen kann, während seine Kopfplatte (in Figur 1 nicht dargestellt) mit einem Injektorgehäuse 2 fest verbunden ist. Wird die Erregungsspannung abgeschaltet, dann zieht sich der untere Teil des piezoelektrischen Aktors 3 wieder in seine Ausgangsposition zurück.Like from the FIG. 1 is further removed, is in the upper part of the FIG. 1 a piezoelectric actuator 3 is arranged. The piezoelectric actuator 3 is arranged in a central bore of the fuel injector 1 such that upon electrical excitation, its bottom plate can expand downwardly, while its top plate (in FIG. 1 not shown) is firmly connected to an injector 2. If the excitation voltage is switched off, then the lower part of the piezoelectric actuator 3 retracts back to its original position.

In der zentralen Bohrung ist des weiteren unterhalb der Bodenplatte des piezoelektrischen Aktors 3 ein hydraulischer Längsausgleich 10 angeordnet. Der hydraulische Längsausgleich 10 bewirkt, dass Längenänderungen des Aktors infolge von Temperaturänderungen, Alterung, Verschleiß etc. auf hydraulischem Wege automatisch ausgeglichen werden, so dass stets der volle Hub des piezoelektrischen Aktors 3 nutzbar ist. Der hydraulische Längsausgleich 10 wird mittels einer Druckfeder 11, die sich an ihrem oberen Ende gegen das Injektorgehäuse 2 abstützt, nach unten gedrückt.In the central bore of the further below the bottom plate of the piezoelectric actuator 3, a hydraulic longitudinal compensation 10 is arranged. The hydraulic longitudinal compensation 10 causes changes in length of the actuator as a result of temperature changes, aging, wear, etc. are compensated automatically by hydraulic means, so that always the full stroke of the piezoelectric actuator 3 is available. The hydraulic longitudinal compensation 10 is pressed by means of a compression spring 11, which is supported at its upper end against the injector 2, down.

Unterhalb des hydraulischen Längsausgleichs 10 ist ein Hebelübersetzer 15 derart angeordnet, dass die Längenänderung des piezoelektrischen Aktors 3 auf den Hebelübersetzer 15 übertragen werden kann. Der Hebelübersetzter 15 hat zwei wesentliche Aufgaben zu erfüllen. Einerseits soll der hydraulische Hebelübersetzer 15 den Hub des piezoelektrischen Aktors 3, der üblicherweise in der Größenordnung von 50 bis 80 µm liegt, vergrößern. Dadurch kann der Öffnungsweg einer Düsennadel 7 vergrößert werden. Eine zweite Aufgabe für den Hebelübersetzer 15 besteht auch darin, dass der Hebelübersetzer 15 gleichzeitig als Hubumkehrer ausgebildet ist. Der Hubumkehrer bewirkt, dass die nach unten gerichtete Längenausrichtung des piezoelektrischen Aktors 3 in eine Hubbewegung für die Düsennadel 7 umgesetzt wird, die nach oben gerichtet ist.Below the hydraulic longitudinal compensation 10, a lever translator 15 is arranged such that the change in length of the piezoelectric actuator 3 can be transmitted to the lever translator 15. The lever translator 15 has two essential tasks to fulfill. On the one hand, the hydraulic lever translator 15 is intended to increase the stroke of the piezoelectric actuator 3, which is usually of the order of magnitude of 50 to 80 μm. As a result, the opening travel of a nozzle needle 7 can be increased. A second task for the lever translator 15 is also that the lever translator 15 is simultaneously designed as a Hubumkehrer. The Hubumkehrer causes the downward length alignment of the piezoelectric actuator 3 is converted into a lifting movement for the nozzle needle 7, which is directed upward.

Zur Umkehrung des Aktorhubs weist der Hebelübersetzer 15 im wesentlichen einen Druckhebel 19 aus, auf den die Druckkraft des piezoelektrischen Aktors 3 mit Hilfe des hydraulischen Längsausgleichs 10 übertragen werden kann. Der Druckhebel 19 ist querliegend in der zentralen Bohrung des Aktorgehäuses 2 angeordnet.To reverse the Aktorhubs, the lever translator 15 is essentially a pressure lever 19, to which the pressure force of the piezoelectric actuator 3 by means of the hydraulic longitudinal compensation 10 can be transmitted. The pressure lever 19 is arranged transversely in the central bore of the actuator housing 2.

Wie in Figur 1 dargestellt ist, stützt sich der Druckhebel 19 mit seinem rechten Teil auf einen festen Auflageblock 14 ab. Der feste Auflageblock 14 ist winkelförmig ausgebildet, wobei sein freier Schenkel in eine Nut einer Düsennadel 7 eingreift, die am Schaft der Düsennadel 7 etwas unterhalb des Kopfendes ringförmig angeordnet ist. Im nicht angesteuerten Zustand, wenn die Düsenadel 7 auf ihrem Ventilsitz aufliegt und dadurch die im unteren Teil des Düsengehäuses 6 angeordneten Spritzlöcher verschließt (in Figur 1 nicht dargestellt), liegt der freie Schenkel des Auflageblocks 14 oben an der Nut der Düsennadel 7 an.As in FIG. 1 is shown, the pressure lever 19 is supported with its right part on a fixed support block 14. The fixed support block 14 is formed angularly, with its free leg engages in a groove of a nozzle needle 7, which at the shaft of the nozzle needle 7 slightly below the The head is arranged in a ring shape. In the non-activated state, when the nozzle needle 7 rests on its valve seat and thereby closes the injection holes arranged in the lower part of the nozzle housing 6 (in FIG FIG. 1 not shown), the free leg of the support block 14 is at the top of the groove of the nozzle needle 7 at.

Der linke Teil des Druckhebels 19 ist beweglich ausgebildet. Unterhalb des linken Teils des Druckhebels 19 ist ein Kipphebel 16 angeordnet, der mit dem beweglichen Teil des Druckhebels 19 in Wirkverbindung steht. Der Kipphebel 16 ist mit seinem freien Schenkel in die Nut des Düsennadel 7 geführt und derart ausgebildet, dass die Düsenadel 7 von ihrem Ventilsitz abgehoben wird, wenn der piezoelektrische Aktor 3 betätigt wird und dabei der Druckhebel 19 auf den Kipphebel 16 drückt.The left part of the pressure lever 19 is designed to be movable. Below the left part of the pressure lever 19, a rocker arm 16 is arranged, which is in operative connection with the movable part of the pressure lever 19. The rocker arm 16 is guided with its free leg into the groove of the nozzle needle 7 and designed such that the nozzle needle 7 is lifted from its valve seat when the piezoelectric actuator 3 is actuated while the pressure lever 19 presses on the rocker arm 16.

Unterhalb des Hebelübersetzers 15 ist ein Gehäuseteil 5 angeordnet. Darunter befindet sich ein Düsengehäuse 6, in dem die Düsennadel 7 zentral geführt wird. Vollständigkeitshalber wird darauf hingewiesen, dass das untere Ende des Düsengehäuses 6 mit Spritzlöchern ausgebildet ist, die bei Ansteuerung des piezoelektrischen Aktors 3 geöffnet bzw. bei Abschaltung der Ansteuerung geschlossen werden (in Figur 1 nicht dargestellt). Zur Sicherstellung, dass die Düsennadel 7 im nicht angesteuerten Zustand die Düsennadel hochdruckdicht verschließt, ist zusätzlich um die Düsennadel 7 herum eine Düsennadelfeder 13 koaxial angeordnet, die sich einerseits gegen eine untere Stirnfläche des Gehäuseteils 5 und mit ihrem zweiten Ende gegen eine Druckfläche der Düsennadel 7 abstützt und dabei die Düsennadel 7 in Richtung ihres Ventilsitzes nach unten drückt.Below the lever translator 15, a housing part 5 is arranged. Below is a nozzle housing 6, in which the nozzle needle 7 is guided centrally. For the sake of completeness, it is pointed out that the lower end of the nozzle housing 6 is formed with spray holes which are opened when the piezoelectric actuator 3 is actuated or closed when the activation is switched off (in FIG FIG. 1 not shown). To ensure that the nozzle needle 7 in the non-actuated state, the nozzle needle closes high pressure-tight, a nozzle needle spring 13 is additionally arranged coaxially around the nozzle needle 7, which on the one hand against a lower end face of the housing part 5 and with its second end against a pressure surface of the nozzle needle. 7 supports and presses the nozzle needle 7 in the direction of its valve seat down.

Das Düsengehäuse 6, das darüber angeordnete Gehäuseteil 5 und das Injektorgehäuse 2 werden mit einer Düsenspannmutter 4 zusammengehalten, wobei die Düsenspannmutter 4 von unten über das Düsengehäuse 6 geführt wird und mit einem Außengewinde des Injektorgehäuses 2 fest verschraubt wird.The nozzle housing 6, the housing part 5 arranged above it and the injector housing 2 are held together with a nozzle retaining nut 4, wherein the nozzle retaining nut 4 is guided from below over the nozzle housing 6 and is firmly screwed to an external thread of the injector housing 2.

Das Gehäuseteil 5 ist als Gehäuseplatte ausgebildet. Alternativ kann das Gehäuseteil beispielsweise auch als Nadelführungskörper oder dergleichen ausgebildet sein.The housing part 5 is formed as a housing plate. Alternatively, the housing part may be formed, for example, as a needle guide body or the like.

Im Bereich des Hebelübersetzers 15 ist ein Hochdruckraum 9 ausgebildet, der mit Kraftstoff, Dieselöl oder Benzin gefüllt ist. Der Hochdruck im Hochdruckraum 9 wird durch eine Druckpumpe des Common-Rail-Einspritzsystems (in Figur 1 nicht dargestellt) erzeugt, wobei der Kraftstoff von der Hochdruckpumpe über entsprechende Kanäle des Kraftstoffinjektors 1 bis zum Hochdruckraum 9 und weiter bis zur Düsenspitze des Düsengehäuses 6 geführt wird. Der Hochdruckraum wird einerseits nach außen hin durch die Wandung des zylinderförmig ausgebildeten Injektorgehäuses 2 nach oben hin begrenzt. Nach unten hin wird der Hochdruckraum einerseits durch den Schaft der Düsennadel 7 begrenzt. Des weiteren erfolgt eine seitliche Begrenzung des Hochdruckraums 9 durch die Wandung des zylinderförmig ausgebildeten Gehäuseteils 5.In the region of the lever translator 15, a high-pressure chamber 9 is formed, which is filled with fuel, diesel oil or gasoline. The high pressure in the high pressure chamber 9 is by a pressure pump of the common rail injection system (in FIG. 1 not shown), wherein the fuel from the high pressure pump via corresponding channels of the fuel injector 1 to the high pressure chamber 9 and on to the nozzle tip of the nozzle housing 6 is performed. The high-pressure chamber is limited on the one hand to the outside through the wall of the cylinder-shaped injector 2 upwards. At the bottom, the high-pressure chamber is bounded on the one hand by the shaft of the nozzle needle 7. Furthermore, there is a lateral boundary of the high-pressure chamber 9 through the wall of the cylinder-shaped housing part. 5

Wie Figur 1 weiter entnehmbar ist, ist die untere Stirnfläche des Kraftstoffinjektors 2, die auf der oberen Stirnfläche des Gehäuseteils 5 aufliegt, als Hochdruckdichtung 12 ausgebildet. Da im Innern des Hochdruckraums 9 ein Kraftstoffdruck, insbesondere bei einem Dieselinjektor von bis zu 2000 bar herrscht, muss diese Hochdruckdichtung 12 besonders zuverlässig und sicher ausgeführt werden. Insbesondere muss sichergestellt sein, dass die Hochdruckdichtung 12 verschleißfrei und dauerhaft ausgebildet ist, insbesondere wenn die Wandstärken der beiden zusammengefügten Gehäuseteile 2,5 unterschiedlich stark sind oder wenn unterschiedliche steife Materialien verwendet werden.As FIG. 1 can be further removed, the lower end face of the fuel injector 2, which rests on the upper end face of the housing part 5, formed as a high-pressure seal 12. Since there is a fuel pressure inside the high-pressure chamber 9, in particular in the case of a diesel injector of up to 2000 bar, this high-pressure seal 12 must be designed to be particularly reliable and safe. In particular, it must be ensured that the high-pressure seal 12 is wear-free and durable, in particular if the wall thicknesses of the two assembled housing parts 2.5 are different degrees or if different rigid materials are used.

Bei dem Ausführungsbeispiel der Erfindung ist die Wandstärke des Injektorgehäuses 2 dünner ausgebildet als die des Gehäuseteils 5. In Figur 2 ist dieser Zusammenhang noch einmal dargestellt. Figur 2 zeigt einen Ausschnitt mit der Hochdruckdichtung 12, wie sie in dem Längsschnitt der Figur 1 auf der rechten Seite dargestellt ist. Die Wandstärke d1 des Injektorgehäuses 2 ist kleiner als die Wandstärke d2 des Gehäuseteils 5. Beide Gehäuseteile 2, 5 werden durch die Düsenspannmutter 4 an der oberen Dichtfläche 8a des Injektorgehäuses 2 und der unteren Dichtfläche 8b des Gehäuseteils 5 durch die Vorspannung der Düsenspannmutter 4 zusammengepresst. Wie in Figur 1 dargestellt ist, zeigen die beiden gegeneinander gerichteten dicken Pfeile im Ausschnitt A, dass die Spannkraft Pv der Düsenspannmutter 4 in Achsrichtung wirkt und dadurch die beiden Dichtflächen 8a, 8b zusammengepresst werden. Auf die beiden Dichtflächen 8a, 8b wirkt jedoch auch der Kraftstoffhochdruck im Hochdruckraum 9. Aufgrund des sehr hohen Kraftstoffdrucks im Hochdruckraum 9 wird die Gehäusewand des Injektorgehäuses 2 radial auseinander gedrückt. Da der Hochdruck auch auf die Gehäusewand des Gehäuseteils 5 einwirkt, wird auch dieses Gehäuse auseinander gedrückt. Dieses ist symbolhaft durch die beiden unterschiedlichen langen Doppelpfeile P1 und P2 dargestellt. Aufgrund der unterschiedlichen Wandstärken d1 bzw. d2 werden auch die beiden Gehäuseteile 2, 5 unterschiedlich stark auseinander gedrückt. Dieses ist symbolisch durch die unterschiedlichen Längen der beiden Pfeile P1 und P2 wieder gegeben.In the embodiment of the invention, the wall thickness of the injector 2 is formed thinner than that of the housing part 5. In FIG. 2 this relationship is shown again. FIG. 2 shows a section with the high pressure seal 12, as shown in the longitudinal section of FIG. 1 on the right side is shown. The wall thickness d1 of the injector housing 2 is smaller than the wall thickness d2 of the housing part 5. Both housing parts 2, 5 are compressed by the nozzle lock nut 4 on the upper sealing surface 8a of the injector housing 2 and the lower sealing surface 8b of the housing part 5 by the bias of the nozzle lock nut 4. As in FIG. 1 is shown, the two oppositely directed thick arrows in the section A, that the clamping force P v of the nozzle lock nut 4 acts in the axial direction and thereby the two sealing surfaces 8a, 8b are pressed together. However, the fuel high pressure in the high-pressure chamber 9 also acts on the two sealing surfaces 8a, 8b. Because of the very high fuel pressure in the high-pressure chamber 9, the housing wall of the injector housing 2 is pressed radially apart. Since the high pressure also acts on the housing wall of the housing part 5, this housing is also pressed apart. This is symbolically represented by the two different long double arrows P 1 and P 2 . Due to the different wall thicknesses d1 and d2, the two housing parts 2, 5 are pressed apart to different degrees. This is symbolically given by the different lengths of the two arrows P 1 and P 2 again.

Um zu verhindern, dass bei Druckwechseln sich die beiden Gehäuseteile 2, 5 an ihren Dichtflächen 8a, 8b gegeneinander verschieben können, ist vorgesehen, dass die beiden Druckflächen 8a, 8b kegelig mit einem Kegelwinkel α ausgebildet sind.In order to prevent pressure changes when the two housing parts 2, 5 can move against each other at their sealing surfaces 8a, 8b, it is provided that the two pressure surfaces 8a, 8b are formed conically with a cone angle α.

Im folgenden wird die Funktionsweise der Hochdruckdichtung näher erläutert.In the following, the operation of the high-pressure seal is explained in detail.

Die kegelige oder gerundete Ausführung der Hochdruckdichtung 12 ist ein Aspekt der Erfindung. Der Kegelwinkel α wird dabei so ausgebildet, dass sich das Bauteil mit der dünneren Wandstärke bzw. der schwächeren Steifigkeit bei Druckentlastung nicht zurückziehen kann. Wie in den Figuren 1 und 2 dargestellt ist, ist der Kegelwinkel α nach unten führend ausgebildet. Dadurch kann sich das Injektorgehäuse 2 mit der geringeren Wandstärke d1 bei Druckanstieg nach außen ausdehnen und gleitet dabei auf den Dichtflächen 8a, 8b. Durch die hohe Spannkraft Pv der Düsenspannmutter 4 werden die beide Dichtflächen 8a, 8b der beiden Gehäuseteile 2, 5 in dieser Position fixiert.The conical or rounded design of the high pressure seal 12 is one aspect of the invention. The cone angle α is formed so that the component with the thinner wall thickness or the weaker stiffness can not withstand pressure relief. As in the Figures 1 and 2 is shown, the cone angle α is formed leading downward. As a result, the injector housing 2 with the smaller wall thickness d1 can expand outward when the pressure rises, thereby sliding on the sealing surfaces 8a, 8b. Due to the high clamping force P v of the nozzle retaining nut 4, the two sealing surfaces 8a, 8b of the two housing parts 2, 5 are fixed in this position.

Bei Druckentlastung wirkt die Spannkraft Pv der Düsenspannmutter 4 weiterhin in axialer Richtung zum Kraftstoffinjektor 1 auf die beiden Dichtflächen 8a, 8b. Bei Druckentlastung in dem Hochdruckraum 9 kann zwischen den beiden Dichtflächen 8a, 8b keine relative Bewegung zueinander stattfinden, da der Kegelwinkel α ein stärkeres Zusammenziehen der Wandung des Injektorgehäuses 2 bei der weiterhin bestehen Spannkraft Pv der Düsenspannmutter 4 verhindert. Die Folge ist, dass die Hochdruckdichtung 12 völlig verschleißfrei und zuverlässig hochdruckdicht abgedichtet ist. Auch bei einer Alterung oder Temperaturwechseln kann sich eine Verschiebung der beiden Dichtflächen, 8a, 8b zueinander nicht ausbilden. Der Kegelwinkel α wird vorzugsweise je nach Anwendung und dem vorherrschenden Kraftstoffdruck zwischen 10 und 20° ausgebildet.When pressure is released, the clamping force P v of the nozzle lock nut 4 continues to act in the axial direction to the fuel injector 1 on the two sealing surfaces 8 a, 8 b. When relieving pressure in the high-pressure chamber 9, no relative movement between the two sealing surfaces 8a, 8b take place, since the cone angle α prevents a stronger contraction of the wall of the injector housing 2 in the still existing clamping force P v of the nozzle retaining nut 4. The result is that the high-pressure seal 12 is completely free of wear and reliably sealed high pressure-tight. Even with aging or temperature changes, a shift of the two sealing surfaces, 8a, 8b to each other can not form. The cone angle α is preferably formed depending on the application and the prevailing fuel pressure between 10 and 20 °.

Figur 3 zeigt eine alternative Ausführung der Dichtflächen 8a, 8b aus Figur 2 mit gerundeten Dichtflächen 8a', 8b'. Die konkave Dichtfläche 8a' liegt bündig an der konvexen Dichtfläche 8b' an. FIG. 3 shows an alternative embodiment of the sealing surfaces 8a, 8b FIG. 2 with rounded sealing surfaces 8a ', 8b'. The concave sealing surface 8a 'is flush with the convex sealing surface 8b'.

Der Radius der konvexen Dichtfläche 8b' ist etwas kleiner als der Radius der konkaven Dichtfläche 8a', so dass die sich die Dichtflächen besser verspannen und ein Dichtring mit erhöhter Flächenpressung entsteht.The radius of the convex sealing surface 8b 'is slightly smaller than the radius of the concave sealing surface 8a', so that the better tighten the sealing surfaces and a sealing ring with increased surface pressure arises.

Claims (10)

  1. A fuel injector with at least two preferentially cylindrical housing parts (2,5) and with a clamping device (4), preferentially a nozzle clamping nut (4), wherein the two housing parts (2,5) are arranged axially lying on top of each other and wherein two adjoining end faces of the two housing parts (2,5) are at least partially embodied high pressure proof as sealing surfaces (8a, 8b) for a high-pressure chamber (9) filled with fuel and firmly pressed together by means of the clamping device (4) wherein
    - the two sealing faces (8a, 8b) lying on top of each other lie flush against each other conically with a predetermined cone angle (α) or
    - preferentially lie convexly/concavely (8b', 8a') flush against each other with a predetermined radius (R), wherein the truncated cone shaped sealing surfaces (8a, 8b) slope towards each other by a few degrees or that the convexly/concavely embodied sealing surfaces (8a', 8b') have such a radius (R) slightly deviating from each other that the sealing effect is increased in a ring-shaped sealing region.
  2. The fuel injector according to Claim 1, characterized in that the cone angle (α) is embodied in such a manner that during operation of the fuel injector (1) the sealing faces are clamped together through at least one-off pressurizing of the fuel injector - preferentially the pressure is in the range of the maximum permissible operating pressure of the fuel injector - so that during a later pressure change in the high-pressure chamber (9) no mutual displacement of the two sealing faces relative to each other (8a, 8b) occurs.
  3. The fuel injector according to Claim 1 or 2, characterized in that the two housing parts (2,5) are embodied with a material of differing stiffness.
  4. The fuel injector according to any one of the preceding claims, characterized in that the two housing parts (2,5) have a wall thickness (d1,d2) differing in size.
  5. The fuel injector according to any one of the preceding claims, characterized in that the cone angle (α) is embodied in such a manner that upon the first pressure increase in the high-pressure chamber (9) the housing part (2) with the lesser wall thickness or the material of lesser stiffness radially expands towards the outside.
  6. The fuel injector according to any one of the preceding claims, characterized in that the sealing faces (8a, 8b) are arranged on an injector housing (2) and a housing plate (5) or a nozzle housing (6).
  7. The fuel injector according to any one of the preceding claims, characterized in that the fuel injector (1) is embodied without leakage oil return.
  8. The fuel injector according to any one of the preceding claims, characterized in that the fuel injector (1) comprises a hydraulic longitudinal compensator and/or a lever translator (15) for actuating a nozzle needle (7).
  9. The fuel injector according to any one of the preceding claims, characterized in that the fuel injector (1) is embodied for a common rail injection system.
  10. The fuel injector according to any one of the preceding claims, characterized in that the fuel injector (1) comprises a piezoelectric actuator (3) which is arranged in the high-pressure chamber (9) and is activatable for injection of diesel oil or petrol.
EP06007432A 2006-04-07 2006-04-07 Fuel injector with a conical high pressure housing sealing Expired - Fee Related EP1843038B1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP06007432A EP1843038B1 (en) 2006-04-07 2006-04-07 Fuel injector with a conical high pressure housing sealing
DE502006003182T DE502006003182D1 (en) 2006-04-07 2006-04-07 Fuel injector with a conical housing high-pressure seal

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP06007432A EP1843038B1 (en) 2006-04-07 2006-04-07 Fuel injector with a conical high pressure housing sealing

Publications (2)

Publication Number Publication Date
EP1843038A1 EP1843038A1 (en) 2007-10-10
EP1843038B1 true EP1843038B1 (en) 2009-03-18

Family

ID=36758405

Family Applications (1)

Application Number Title Priority Date Filing Date
EP06007432A Expired - Fee Related EP1843038B1 (en) 2006-04-07 2006-04-07 Fuel injector with a conical high pressure housing sealing

Country Status (2)

Country Link
EP (1) EP1843038B1 (en)
DE (1) DE502006003182D1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102282360B (en) * 2009-01-13 2016-04-27 罗伯特·博世有限公司 Fuelinjection nozzle

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1692107A (en) * 1924-09-17 1928-11-20 Archaouloff Vadime Direct-injection fuel atomizer for internal-combustion engines
DE19608575B4 (en) * 1996-03-06 2005-10-20 Bosch Gmbh Robert Fuel injection valve for internal combustion engines
DE10254186A1 (en) * 2002-11-20 2004-06-17 Siemens Ag Injector with a directly driven register nozzle needle for fuel injection into an internal combustion engine
ITBO20040466A1 (en) * 2004-07-23 2004-10-23 Magneti Marelli Holding Spa FUEL INJECTOR WITH ELECTROMAGNETIC ACTUATION

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102282360B (en) * 2009-01-13 2016-04-27 罗伯特·博世有限公司 Fuelinjection nozzle

Also Published As

Publication number Publication date
EP1843038A1 (en) 2007-10-10
DE502006003182D1 (en) 2009-04-30

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