EP1505295A1 - Method of positioning an actuator of a fuel injector and apparatus to carry out the method - Google Patents

Method of positioning an actuator of a fuel injector and apparatus to carry out the method Download PDF

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Publication number
EP1505295A1
EP1505295A1 EP20040026927 EP04026927A EP1505295A1 EP 1505295 A1 EP1505295 A1 EP 1505295A1 EP 20040026927 EP20040026927 EP 20040026927 EP 04026927 A EP04026927 A EP 04026927A EP 1505295 A1 EP1505295 A1 EP 1505295A1
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EP
European Patent Office
Prior art keywords
actuator
housing
piezoelectric actuator
fuel injector
bottom plate
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.)
Granted
Application number
EP20040026927
Other languages
German (de)
French (fr)
Other versions
EP1505295B1 (en
Inventor
Wilhelm Frank
Wendelin KLÜGL
Stefan Lehmann
Günter LEWENTZ
Martin Dr. Neumaier
Reda Rizk
Gerd Dr. Schmutzler
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
Original Assignee
Siemens AG
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Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Publication of EP1505295A1 publication Critical patent/EP1505295A1/en
Application granted granted Critical
Publication of EP1505295B1 publication Critical patent/EP1505295B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • 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
    • 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
    • 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
    • F02M2200/70—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
    • 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
    • F02M2200/80—Fuel injection apparatus manufacture, repair or assembly
    • F02M2200/8053—Fuel injection apparatus manufacture, repair or assembly involving mechanical deformation of the apparatus or parts thereof
    • 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
    • F02M2200/80—Fuel injection apparatus manufacture, repair or assembly
    • F02M2200/8069—Fuel injection apparatus manufacture, repair or assembly involving removal of material from the fuel apparatus, e.g. by punching, hydro-erosion or mechanical operation
    • 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
    • F02M2200/80—Fuel injection apparatus manufacture, repair or assembly
    • F02M2200/8092—Fuel injection apparatus manufacture, repair or assembly adjusting or calibration
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/598—With repair, tapping, assembly, or disassembly means
    • Y10T137/5987—Solenoid or electromagnetically operated valve
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49405—Valve or choke making
    • Y10T29/49412—Valve or choke making with assembly, disassembly or composite article making
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49405—Valve or choke making
    • Y10T29/49412—Valve or choke making with assembly, disassembly or composite article making
    • Y10T29/49416—Valve or choke making with assembly, disassembly or composite article making with material shaping or cutting
    • Y10T29/49423—Valve or choke making with assembly, disassembly or composite article making with material shaping or cutting including metal deforming

Definitions

  • the invention relates to a method for positioning the Actuator in a fuel injector according to the preamble of claims 1; a device for carrying out the method according to the preamble of claim 2 and a fuel injector according to the preamble of the claim 6th
  • the fuel injector generally comprises an injection valve, the hydraulically opened by a servo valve and is closed to the timing of the injection process to specify exactly in the combustion chamber.
  • the servo valve is thereby controlled by an electrically Actuator actuated, in particular, the use of piezoelectric Actuators to achieve sufficiently short switching times has proved favorable.
  • a piezoelectric Actuator becomes a longitudinal strain by applying voltage caused to be transmitted to the servo valve, which in turn opens or closes the injection valve.
  • the lying in the micron range longitudinal expansion of the piezoelectric Actuator can operate the servo valve, this is Elongation generally either mechanically by a lever levers mounted in fuel or hydraulically reinforced by a pressure chamber.
  • a fuel injector with a piezo actuator and hydraulic Reinforcement is described, for example, in U.S. Patent No. 5,779,149.
  • the idle stroke should on the one hand be as small as possible, always with defined conditions and to minimize the dynamic loads hold. On the other hand, there must always be a minimum clearance between the actor and actuator can be guaranteed to malfunction in the To avoid operation.
  • the setting of the idle stroke in the fuel injector is so far so made that the exact arrangement of each Components of the fuel injector and in particular their Distances to each other mathematically from the dimensions of this Components are determined.
  • each component must be individually measured consuming. After measuring the idle stroke is then through between the Injector housing and the actuator or the servo valve arranged Shims set, the minimum tolerance and therefore very much in production are expensive.
  • the object of the present invention is to provide a method for Positioning the actuator in a fuel injector and an apparatus for carrying out such a method to create, in which or at a low cost Reliable positioning of the actuator in the Fuel injector is possible and the one or more suitable for serial production Function test of the fuel injector allowed.
  • the above object is therefore solved by the setting the idle stroke is made so that the piezoelectric actuator before its installation in the fuel injector a defined Voltage is applied to a longitudinal expansion of the piezo elements cause exactly the desired idle stroke equivalent.
  • a defined Voltage is applied to a longitudinal expansion of the piezo elements cause exactly the desired idle stroke equivalent.
  • the bottom plate of the piezoelectric actuator with the housing the actuator ground flat In the current or voltage-free Condition is the bottom plate relative to the actuator housing then to return to the idle stroke.
  • a compensation ring between the piezoelectric actuator and the housing of the fuel injector intended.
  • the compensation ring is in the down to the piezoelectric actuator completely assembled fuel injector inserted and by a pretensioner with a plane effective area so long deformed, until the servo valve lifts from its valve seat. Then screw in place of the biasing device the piezo actuator until it stops at the balancing ring in the Injector housing, so inevitably arises before as specified above Leerhub between the bottom plate the piezoelectric actuator and the actuator of the fuel injector servo-valve one.
  • This is an active connection between the piezoelectric actuator and the actuator for the servo valve formed with fixed positions such that the Leerhub between piezoelectric actuator and actuator despite the inevitable Manufacturing tolerances of the individual components always corresponds to the predetermined value.
  • the balancing ring is preferably made of soft iron or soft copper.
  • the piezoelectric actuator before its installation without voltage applied plan be ground, the intended Idle stroke during the deformation of the compensation ring via a survey is set on the pretensioner.
  • the Biasing device not from a flat stamp, but from a stamp with embossed front.
  • the drawing shows schematically a sectional view of a fuel injector in the area the connection between a piezoelectric actuator and a Actuator for a servo valve.
  • the figure of the drawing shows in section a part of an injector for fuel injection into the combustion chamber of a Internal combustion engine in a common rail system.
  • a piezoelectric actuator 2 with a Housing 3 and a bottom plate 4 screwed.
  • a piezoelectric element array (not shown in detail), with the bottom plate 4 communicates. If to the piezoelectric element via (Also not shown) supply lines applied a voltage is changed, this changes their length, and the bottom plate 4 changed thereby their position relative to the actuator housing. 3
  • the piezoelectric actuator 2 acts when it is electrically driven, to a transmission element 5 in the fuel injector housing. 1 one. This means that when applying a voltage to the said piezoelectric element arrangement, the bottom plate 4 of the piezoelectric actuator 2 due to the voltage applied by the applied voltage Longitudinal expansion of the piezoelectric elements from the actuator housing outside, in the drawing down, shifts, and also the transmission element 5 is moved accordingly.
  • the transmission element 5 in the fuel injector housing 1 in turn acts on a valve stem 6, which at a Valve element 7 of a servo valve is applied.
  • the transmission element 5 shown can also be a provided hydraulic translation of the stroke of the piezoelectric actuator 2 become.
  • the bottom plate 4 of the piezoelectric actuator acts 2 on an actuator for the servo valve of Fuel injector. Piezoelectric actuator 2 and actuator form the actuator for the servo valve.
  • the piezoelectric actuator 2 before installation in the injector 1 edited so that the bottom plate 4 to exactly the predetermined Leerhub .DELTA.h relative to the housing 3 of the piezoelectric actuator back is.
  • the piezoelectric actuator 2 before installation exactly the voltage U is applied in the injector housing 1, which corresponds to a longitudinal expansion of the piezoelectric element arrangement the predetermined idle stroke .DELTA.h causes, and it will be the case 3 and the bottom plate 4 of the piezoelectric actuator 2 when applied Tension U flat ground.
  • the piezoelectric actuator 2 can do this, for example, in a grinding machine be clamped, the voltage U via slip rings is supplied.
  • the balancing ring 9 made of a soft, deformable material how soft iron or soft copper is made in the completely assembled except for the piezoelectric actuator 2 Fuel injector inserted. Then, instead of the piezoelectric actuator 2, a biasing device in the fuel injector screwed in, whose front, the side of the piezoelectric actuator 2 corresponds to the bottom plate 4, completely flat is. The pretensioner is screwed in until due to the actuation of the transmission element 5 by the plane front of the biasing device, the valve element. 7 of the servo valve begins to lift off its valve seat. There becomes the balancing ring made of a soft material 9, on the also the flat front of the Pretensioner acts permanently by material flow deformed. The balance ring 9 then retains when removing the Biasing means the thickness that he had as the biasing means just screwed in that far the servo valve began to open.
  • the piezoelectric actuator 2 instead of the biasing device, the piezoelectric actuator 2, the bottom plate 4 as described above to the given idle stroke .DELTA.h lags, until it stops in the Screwed housing 1 of the fuel injector, that is until the piezoelectric actuator housing 3 abuts against the compensation ring 9, so the leading edge of the Piezoaktorgepuruses 3 is exactly at the height, the front of the pretensioner had when the servo valve began to open.
  • the bottom plate 4 of the piezoelectric actuator 2 is set back by the given idle stroke ⁇ h the idle stroke of the actuator in the fuel injector, that is the game between the bottom plate 4 of the piezoelectric actuator. 2 and servo valve, exactly the predetermined value ⁇ h.
  • the piezoelectric actuator 2 before installation in the Injektorgepuruse 1 edited so that the bottom plate 4 and the housing 3 of the piezoelectric actuator 2 in the ready to install Condition, but ground without applied voltage become.
  • the bottom plate 4 of the piezoelectric actuator 2 is located thus at night the grinding process on exactly the same Height as the housing 3 of the piezoelectric actuator 2 Biasing device for deformation of the compensation ring 9 no plane front but a front on that on the one or more locations at which or the biasing device acting on the transmission element 5, a survey the height ⁇ h has.
  • the central effective surface on the pretensioner, with the transmission element 5 engages stands with others Words in installation direction by the predetermined value .DELTA.h for the idle stroke with respect to the circumferential effect on the edge, which engages with the balancing ring 9.
  • the pretensioner is the same as in the former embodiment instead of the piezoelectric actuator 2 so far in the Fuel injector screwed in until actuated of the transmission element 5 through the raised portion the front of the biasing device, the valve element. 7 of the servo valve begins to open.
  • the balancing ring 9 is while remaining deformed as above. Subsequently, instead of the Biasing device of the piezoelectric actuator 2, in the housing 3 and Bottom plate 4 were ground without voltage applied, until it stops at the compensation ring 9 in the housing. 1 screwed the fuel injector.
  • the idle stroke between Piezo actuator 2 and servo valve exactly the predetermined value .DELTA.h on, since the thickness of the balancing ring 9 with the biasing means is adjusted so that during operation of the Fuel injector begins to open the servo valve after the bottom plate 4 of the piezoelectric actuator 2 in its control has covered the free travel ⁇ h.

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

Abstract

The method involves applying a voltage to the piezo actuator (2) in the drive corresp. to a predefined idle stroke; surface grinding the actuator housing (3) and base plate (4) with the voltage applied before screwing the piezo actuator into the injector housing (1); and providing a compensation ring (9) between the injector and actuator housings, which is permanently deformed before screwing the actuator into the injector housing by a clamping device with a flat leading side until its thickness is such that a valve element (7) of a servovalve starts to open under the action of the leading side on a transfer element (5).

Description

Die Erfindung betrifft ein Verfahren zum Positionieren des Stellantriebs in einem Kraftstoffinjektor gemäß dem Oberbegriff der Patentansprüche 1; eine Vorrichtung zur Durchführung des Verfahrens gemäß dem Oberbegriff des Patentanspruchs 2 und einen Kraftstoffinjektor gemäß dem Oberbegriff des Patentanspruchs 6.The invention relates to a method for positioning the Actuator in a fuel injector according to the preamble of claims 1; a device for carrying out the method according to the preamble of claim 2 and a fuel injector according to the preamble of the claim 6th

Bei der Kraftstoffversorgung von Verbrennungsmotoren werden zunehmend Speichereinspritzsysteme verwendet, bei denen mit sehr hohen Einspritzdrücken und schnellen Schaltgeschwindigkeiten gearbeitet wird. Solche Einspritzsysteme sind als Common-Rail-Systeme (für Dieselmotoren) und HPDI-Einspritzsysteme (für Ottomotoren) bekannt. Bei diesen Speichereinspritzsystemen wird der Kraftstoff mittels einer Hochdruckpumpe in einen allen Zylindern des Motors gemeinsamen Hochdruckspeicher gefördert, von dem aus der Kraftstoff mit Hilfe von Kraftstoffinjektoren in die einzelnen Brennkammern des Verbrennungsmotors eingespritzt wird.When the fuel supply of internal combustion engines increasingly used in storage injection systems with which very high injection pressures and fast switching speeds is working. Such injection systems are called common-rail systems (for diesel engines) and HPDI injection systems (for gasoline engines) known. In these storage injection systems is the fuel by means of a high-pressure pump in a high-pressure accumulator common to all cylinders of the engine promoted, from which the fuel with the help of fuel injectors in the individual combustion chambers of the Internal combustion engine is injected.

Der Kraftstoffinjektor umfasst im Allgemeinen ein Einspritzventil, das hydraulisch von einem Servoventil geöffnet und geschlossen wird, um den zeitlichen Verlauf des Einspritzvorgangs in der Brennkammer genau festzulegen.The fuel injector generally comprises an injection valve, the hydraulically opened by a servo valve and is closed to the timing of the injection process to specify exactly in the combustion chamber.

Das Servoventil wird dabei von einem elektrisch angesteuerten Aktor betätigt, wobei sich vor allem der Einsatz von piezoelektrischen Aktoren zum Erzielen ausreichend kurzer Schaltzeiten als günstig erwiesen hat. In einem solchen piezoelektrischen Aktor wird durch Anlegen von Spannung eine Längsdehnung hervorgerufen, die auf das Servoventil übertragen wird, das dann wiederum das Einspritzventil öffnet oder schließt. The servo valve is thereby controlled by an electrically Actuator actuated, in particular, the use of piezoelectric Actuators to achieve sufficiently short switching times has proved favorable. In such a piezoelectric Actuator becomes a longitudinal strain by applying voltage caused to be transmitted to the servo valve, which in turn opens or closes the injection valve.

Damit die im µm-Bereich liegende Längsdehnung des piezoelektrischen Aktors das Servoventil betätigen kann, wird diese Längsdehnung im allgemeinen entweder mechanisch durch einen in Kraftstoff gelagerten Hebelübersetzer oder hydraulisch durch einen Druckraum verstärkt.Thus, the lying in the micron range longitudinal expansion of the piezoelectric Actuator can operate the servo valve, this is Elongation generally either mechanically by a lever levers mounted in fuel or hydraulically reinforced by a pressure chamber.

Ein Kraftstoffinjektor mit einem Piezoaktor und hydraulischer Verstärkung ist zum Beispiel im US-Patent Nr. 5 779 149 beschrieben.A fuel injector with a piezo actuator and hydraulic Reinforcement is described, for example, in U.S. Patent No. 5,779,149.

Um die für einen optimalen Verbrennungsverlauf erforderlichen hohen Schaltgeschwindigkeiten und kleinen Einspritzmengen mit dem Kraftstoffinjektor erzielen zu können, ist es erforderlich, den Kraftstoffinjektor sehr genau einzustellen.To those required for optimal combustion process high switching speeds and small injection quantities with To achieve the fuel injector, it is necessary to adjust the fuel injector very accurately.

Dies gilt insbesondere für den Leerhub zwischen dem piezoelektrischen Aktor und dem Servoventil. Der Leerhub soll einerseits möglichst klein sein, um stets definierte Bedingungen zu haben und um die dynamischen Belastungen gering zu halten. Andererseits muss stets ein Mindestspiel zwischen Aktor und Stellelement gewährleistet sein, um Fehlfunktionen im Betrieb zu vermeiden.This is especially true for the idle stroke between the piezoelectric Actuator and the servo valve. The idle stroke should on the one hand be as small as possible, always with defined conditions and to minimize the dynamic loads hold. On the other hand, there must always be a minimum clearance between the actor and actuator can be guaranteed to malfunction in the To avoid operation.

Die Einstellung des Leerhubs im Kraftstoffinjektor wird bisher so vorgenommen, dass die genaue Anordnung der einzelnen Komponenten des Kraftstoffinjektors und insbesondere deren Abstände zueinander rechnerisch aus den Abmessungen dieser Komponenten ermittelt werden.The setting of the idle stroke in the fuel injector is so far so made that the exact arrangement of each Components of the fuel injector and in particular their Distances to each other mathematically from the dimensions of this Components are determined.

Dazu muss jede Komponente einzeln aufwendig vermessen werden. Nach dem Ausmessen wird der Leerhub dann durch zwischen dem Injektorgehäuse und dem Aktor bzw. dem Servoventil angeordnete Einstellscheiben eingestellt, die nur eine minimale Toleranz aufweisen dürfen und die deshalb in der Fertigung sehr aufwendig sind. For this purpose, each component must be individually measured consuming. After measuring the idle stroke is then through between the Injector housing and the actuator or the servo valve arranged Shims set, the minimum tolerance and therefore very much in production are expensive.

Um den eingestellten Leerhub zu überprüfen, ist es bisher weiterhin erforderlich, den Kraftstoffinjektor komplett zusammenzubauen und unter Betriebsbedingungen zu testen. Falls Funktionsfehler festgestellt werden, muss der Kraftstoffinjektor nach dem Testlauf wieder vollständig in seine Einzelteile zerlegt, neu vermessen und eventuell nachgearbeitet werden bzw. es müssen Einstellscheiben ausgetauscht werden.To check the set idle stroke, it is so far further required to completely assemble the fuel injector and to test under operating conditions. If Functional errors must be detected, the fuel injector after the test run again completely into its individual parts disassembled, re-measured and possibly reworked or it must be replaced shims.

Aufgabe der vorliegenden Erfindung ist es, ein Verfahren zum Positionieren des Stellantriebs in einem Kraftstoffinjektor und eine Vorrichtung zur Durchführung eines solchen Verfahrens zu schaffen, bei dem bzw. bei der mit geringem Aufwand ein zuverlässiges Positionieren des Stellantriebs im Kraftstoffinjektor möglich ist und das bzw. die eine serientaugliche Funktionsprüfung des Kraftstoffinjektors erlaubt.The object of the present invention is to provide a method for Positioning the actuator in a fuel injector and an apparatus for carrying out such a method to create, in which or at a low cost Reliable positioning of the actuator in the Fuel injector is possible and the one or more suitable for serial production Function test of the fuel injector allowed.

Diese Aufgabe wird erfindungsgemäß mit den im Patentanspruch 1, im Patentanspruch 2 oder im Patentanspruch 6 angegebenen Maßnahmen gelöst. Bevorzugte Ausführungsformen der Erfindung sind in den Unteransprüchen angeführt.This object is achieved with the in the claim 1, specified in claim 2 or in claim 6 Measures resolved. Preferred embodiments of the invention are listed in the subclaims.

Die obige Aufgabe wird demnach dadurch gelöst, dass die Einstellung des Leerhubs so vorgenommen wird, dass an den Piezoaktor vor dessen Einbau in den Kraftstoffinjektor eine definierte Spannung angelegt wird, um eine Längsdehnung der Piezoelemente hervorzurufen, die exakt dem gewünschten Leerhub entspricht. In diesem Zustand, das heißt bei anliegender Spannung, wird die Bodenplatte des Piezoaktors mit dem Gehäuse des Aktors plan geschliffen. Im strom- bzw. spannungslosen Zustand steht die Bodenplatte gegenüber dem Aktorgehäuse dann um den Leerhub zurück. Erfindungsgemäß ist ein Ausgleichsring zwischen Piezoaktor und dem Gehäuse des Kraftstoffinjektors vorgesehen. Der Ausgleichsring wird in den bis auf den Piezoaktor komplett zusammengebauten Kraftstoffinjektor eingelegt und durch eine Vorspanneinrichtung mit planer Wirkfläche so lange verformt, bis das Servoventil von seinem Ventilsitz abhebt. Schraubt man anschließend anstelle der Vorspanneinrichtung den Piezoaktor bis zum Anschlag am Ausgleichsring in das Injektorgehäuse ein, so stellt sich zwangsläufig der vorher wie oben angegeben eingestellte Leerhub zwischen der Bodenplatte des Piezoaktors und dem Stellelement des Kraftstoffinjektor-Servo-ventils ein. Damit wird eine Wirkverbindung zwischen dem Piezoaktor und dem Stellelement für das Servoventil mit festgelegten Positionen derart ausgebildet, dass der Leerhub zwischen Piezoaktor und Stellelement trotz der unvermeidlichen Herstellungstoleranzen der einzelnen Bauteile immer dem vorgegebenen Wert entspricht.The above object is therefore solved by the setting the idle stroke is made so that the piezoelectric actuator before its installation in the fuel injector a defined Voltage is applied to a longitudinal expansion of the piezo elements cause exactly the desired idle stroke equivalent. In this condition, that is, when it is adjacent Voltage, the bottom plate of the piezoelectric actuator with the housing the actuator ground flat. In the current or voltage-free Condition is the bottom plate relative to the actuator housing then to return to the idle stroke. According to the invention, a compensation ring between the piezoelectric actuator and the housing of the fuel injector intended. The compensation ring is in the down to the piezoelectric actuator completely assembled fuel injector inserted and by a pretensioner with a plane effective area so long deformed, until the servo valve lifts from its valve seat. Then screw in place of the biasing device the piezo actuator until it stops at the balancing ring in the Injector housing, so inevitably arises before as specified above Leerhub between the bottom plate the piezoelectric actuator and the actuator of the fuel injector servo-valve one. This is an active connection between the piezoelectric actuator and the actuator for the servo valve formed with fixed positions such that the Leerhub between piezoelectric actuator and actuator despite the inevitable Manufacturing tolerances of the individual components always corresponds to the predetermined value.

Zum Planschleifen von Gehäuse und Bodenplatte des Piezoaktors wird dieser vorzugsweise in eine Schleifmaschine eingespannt, wobei die vorgegebene Spannung über Schleifringe an den Piezoaktor angelegt wird. Der Ausgleichsring besteht vorzugsweise aus Weicheisen oder weichem Kupfer. Beim Vorspannen fließt das Material des Ausgleichsrings, wodurch sich die Dicke des Ausgleichsrings bleibend verändert.For surface grinding of housing and bottom plate of the piezoelectric actuator this is preferably clamped in a grinding machine, where the predetermined voltage via slip rings to the piezoelectric actuator is created. The balancing ring is preferably made of soft iron or soft copper. When preloading flows the material of the balance ring, which increases the thickness of the Balancing ring changed permanently.

Alternativ kann auch der Piezoaktor vor seinem Einbau ohne anliegende Spannung plan geschliffen werden, wobei der vorgesehene Leerhub bei der Verformung des Ausgleichsrings über eine Erhebung an der Vorspanneinrichtung eingestellt wird. Bei dieser alternativen Ausführungsform besteht somit die Vorspanneinrichtung nicht aus einem ebenen Stempel, sondern aus einem Stempel mit geprägter Vorderseite.Alternatively, the piezoelectric actuator before its installation without voltage applied plan be ground, the intended Idle stroke during the deformation of the compensation ring via a survey is set on the pretensioner. In this alternative embodiment is thus the Biasing device not from a flat stamp, but from a stamp with embossed front.

Ausführungsbeispiele der Erfindung werden im Folgenden anhand der Zeichnung näher erläutert. Die Zeichnung zeigt schematisch eine Schnittansicht eines Kraftstoffinjektors im Bereich der Verbindung zwischen einem Piezoaktor und einem Stellantrieb für ein Servoventil.Embodiments of the invention will be described below explained in detail the drawing. The drawing shows schematically a sectional view of a fuel injector in the area the connection between a piezoelectric actuator and a Actuator for a servo valve.

Die Figur der Zeichnung zeigt im Schnitt einen Teil eines Injektors zur Kraftstoffeinspritzung in den Brennraum eines Verbrennungsmotors bei einem Common-Rail-System. In das Gehäuse 1 des Kraftstoffinjektors ist ein Piezoaktor 2 mit einem Gehäuse 3 und einer Bodenplatte 4 eingeschraubt. Im Gehäuse 3 des Piezoaktors 2 befindet sich eine Piezoelementanordnung (im Einzelnen nicht gezeigt), mit der die Bodenplatte 4 in Verbindung steht. Wenn an die Piezoelementanordnung über (ebenfalls nicht gezeigte) Zuleitungen eine Spannung angelegt wird, verändert diese ihre Länge, und die Bodenplatte 4 verändert dadurch ihre Lage bezüglich des Aktorgehäuses 3.The figure of the drawing shows in section a part of an injector for fuel injection into the combustion chamber of a Internal combustion engine in a common rail system. In the case 1 of the fuel injector is a piezoelectric actuator 2 with a Housing 3 and a bottom plate 4 screwed. In the case 3 of the piezoelectric actuator 2 is a piezoelectric element array (not shown in detail), with the bottom plate 4 communicates. If to the piezoelectric element via (Also not shown) supply lines applied a voltage is changed, this changes their length, and the bottom plate 4 changed thereby their position relative to the actuator housing. 3

Der Piezoaktor 2 wirkt, wenn er elektrisch angesteuert wird, auf ein Übertragungselement 5 im Kraftstoffinjektorgehäuse 1 ein. Das heißt, dass sich beim Anlegen einer Spannung an die genannte Piezoelementanordnung die Bodenplatte 4 des Piezoaktors 2 aufgrund der von der angelegten Spannung hervorgerufenen Längsdehnung der Piezoelemente aus dem Aktorgehäuse nach außen, in der Zeichnung nach unten, verschiebt, wobei auch das Übertragungselement 5 entsprechend bewegt wird.The piezoelectric actuator 2 acts when it is electrically driven, to a transmission element 5 in the fuel injector housing. 1 one. This means that when applying a voltage to the said piezoelectric element arrangement, the bottom plate 4 of the piezoelectric actuator 2 due to the voltage applied by the applied voltage Longitudinal expansion of the piezoelectric elements from the actuator housing outside, in the drawing down, shifts, and also the transmission element 5 is moved accordingly.

Das Übertragungselement 5 im Kraftstoffinjektorgehäuse 1 wirkt seinerseits auf einen Ventilstößel 6 ein, der an einem Ventilelement 7 eines Servoventils anliegt. Das Ventilelement 7 wird, solange der Piezoaktor 2 nicht angesteuert ist, von einer Feder 8 in seinen Ventilsitz gedrückt.The transmission element 5 in the fuel injector housing 1 in turn acts on a valve stem 6, which at a Valve element 7 of a servo valve is applied. The valve element 7, as long as the piezoelectric actuator 2 is not driven, from a spring 8 is pressed into its valve seat.

Statt des gezeigten Übertragungselements 5 kann auch eine hydraulische Übersetzung des Hubs des Piezoaktors 2 vorgesehen werden. Im Allgemeinen wirkt die Bodenplatte 4 des Piezoaktors 2 auf ein Stellelement für das Servoventil des Kraftstoffinjektors ein. Piezoaktor 2 und Stellelement bilden den Stellantrieb für das Servoventil.Instead of the transmission element 5 shown can also be a provided hydraulic translation of the stroke of the piezoelectric actuator 2 become. In general, the bottom plate 4 of the piezoelectric actuator acts 2 on an actuator for the servo valve of Fuel injector. Piezoelectric actuator 2 and actuator form the actuator for the servo valve.

Beim Abheben des Ventilelements 7 von seinem Sitz, das heißt beim Öffnen des Servoventils, kann auf die bekannte Weise (siehe z.B. das eingangs genannte US-Patent 5 779 149) Kraftstoff aus der Steuerkammer des im Kraftstoffinjektor enthaltenen Einspritzventils am Ventilelement 7 vorbei abfließen, wodurch sich der Druck in der Steuerkammer verringert und das Einspritzventil öffnet. When lifting the valve element 7 from its seat, that is when opening the servo valve, can in the known way (see, for example, U.S. Patent 5,779,149, cited at the outset) fuel from the control chamber of the fuel injector contained Drain fuel injector valve element 7 past, whereby the pressure in the control chamber decreases and the Injector opens.

Bei einer Beendigung der Ansteuerung des Piezoaktors 2 und der Rückkehr von Übertragungselement 5 und Ventilstößel 6 in die Ausgangsstellung wird das Ventilelement 7 des Servoventils von der Feder 8 wieder in seinen Sitz gedrückt, so dass sich in der Folge der Druck in der Steuerkammer des Einspritzventils wieder erhöht und das Einspritzventil schließt.At a termination of the control of the piezoelectric actuator 2 and the return of transmission element 5 and valve stem 6 in the starting position becomes the valve element 7 of the servo valve pushed back into its seat by the spring 8, so that as a result, the pressure in the control chamber of the injector again increased and the injection valve closes.

Zwischen dem Gehäuse 3 des Piezoaktors 2 und dem Gehäuse 1 des Kraftstoffinjektors befindet sich ein Ausgleichsring 9.Between the housing 3 of the piezoelectric actuator 2 and the housing first the fuel injector is a compensation ring. 9

Bei der Ansteuerung des Piezoaktors 2 bewegt sich somit die Bodenplatte 4 des Piezoaktors relativ zu dessen Gehäuse 3, das im Einbauzustand fest in das Gehäuse 1 des Kraftstoffinjektors eingeschraubt ist. Das Übertragungselement 5, das ein mechanischer Hebelübersetzer oder ein hydraulischer Übersetzer sein kann, überträgt diese Bewegung verstärkt auf den Ventilstößel 6, der das Ventilelement 7 des Servoventils betätigt.When driving the piezoelectric actuator 2 thus moves the Bottom plate 4 of the piezoelectric actuator relative to the housing 3, in the installed state firmly in the housing 1 of the fuel injector is screwed. The transmission element 5, the one mechanical lever translator or a hydraulic translator can transfer this movement more intensively to the Valve tappet 6, which actuates the valve element 7 of the servo valve.

Zur Einstellung eines definierten Leerhubes Δh im Stellantrieb aus Piezoaktor 2, Übertragungselement 5 und Ventilstößel 6 wird der Piezoaktor 2 vor dem Einbau in das Injektorgehäuse 1 so bearbeitet, dass die Bodenplatte 4 um genau den vorgegebenen Leerhub Δh gegenüber dem Gehäuse 3 des Piezoaktors zurücksteht. Dazu wird an den Piezoaktor 2 vor dem Einbau in das Injektorgehäuse 1 genau die Spannung U angelegt, die eine Längsdehnung der Piezoelementanordnung entsprechend dem vorgegebenen Leerhub Δh bewirkt, und es werden das Gehäuse 3 und die Bodenplatte 4 des Piezoaktors 2 bei angelegter Spannung U plangeschliffen.For setting a defined idle stroke Δh in the actuator from piezoelectric actuator 2, transmission element 5 and valve tappet 6, the piezoelectric actuator 2 before installation in the injector 1 edited so that the bottom plate 4 to exactly the predetermined Leerhub .DELTA.h relative to the housing 3 of the piezoelectric actuator back is. For this purpose, the piezoelectric actuator 2 before installation exactly the voltage U is applied in the injector housing 1, which corresponds to a longitudinal expansion of the piezoelectric element arrangement the predetermined idle stroke .DELTA.h causes, and it will be the case 3 and the bottom plate 4 of the piezoelectric actuator 2 when applied Tension U flat ground.

Der Piezoaktor 2 kann dazu zum Beispiel in eine Schleifmaschine eingespannt werden, wobei die Spannung U über Schleifringe zugeführt wird. The piezoelectric actuator 2 can do this, for example, in a grinding machine be clamped, the voltage U via slip rings is supplied.

Nach dem Schleifvorgang und nach Wegnahme der Spannung U steht dann die Bodenplatte 4 um den vorgegebenen Leerhub Δh gegenüber dem Gehäuse 3 des Piezoaktors 2 zurück.After the grinding process and after removing the voltage U then stands the bottom plate 4 by the predetermined idle stroke .DELTA.h relative to the housing 3 of the piezoelectric actuator 2 back.

Die Herstellungs- und sonstigen Toleranzen seitens des Kraftstoffinjektors werden durch den Ausgleichsring 9 ausgeglichen.The manufacturing and other tolerances on the part of Fuel injector are compensated by the balance ring 9.

Der Ausgleichsring 9, der aus einem weichen, verformbaren Material wie Weicheisen oder weichem Kupfer besteht, wird in den bis auf den Piezoaktor 2 komplett zusammengebauten Kraftstoffinjektor eingelegt. Dann wird anstelle des Piezoaktors 2 eine Vorspanneinrichtung in den Kraftstoffinjektor eingeschraubt, deren Vorderseite, die der Seite des Piezoaktors 2 mit der Bodenplatte 4 entspricht, vollständig plan ist. Die Vorspanneinrichtung wird so weit eingeschraubt, bis aufgrund der Betätigung des Übertragungselements 5 durch die plane Vorderseite der Vorspanneinrichtung das Ventilelement 7 des Servoventils von seinem Ventilsitz abzuheben beginnt. Dabei wird der aus einem weichen Material bestehende Ausgleichsring 9, auf den ebenfalls die plane Vorderseite der Vorspanneinrichtung einwirkt, durch Materialfließen dauerhaft verformt. Der Ausgleichsring 9 behält dann beim Entfernen der Vorspanneinrichtung die Dicke, die er hatte, als die Vorspanneinrichtung gerade so weit eingeschraubt war, dass sich das Servoventil zu öffnen begann.The balancing ring 9, made of a soft, deformable material how soft iron or soft copper is made in the completely assembled except for the piezoelectric actuator 2 Fuel injector inserted. Then, instead of the piezoelectric actuator 2, a biasing device in the fuel injector screwed in, whose front, the side of the piezoelectric actuator 2 corresponds to the bottom plate 4, completely flat is. The pretensioner is screwed in until due to the actuation of the transmission element 5 by the plane front of the biasing device, the valve element. 7 of the servo valve begins to lift off its valve seat. there becomes the balancing ring made of a soft material 9, on the also the flat front of the Pretensioner acts permanently by material flow deformed. The balance ring 9 then retains when removing the Biasing means the thickness that he had as the biasing means just screwed in that far the servo valve began to open.

Wird schließlich anstelle der Vorspanneinrichtung der Piezoaktor 2, dessen Bodenplatte 4 wie oben beschrieben um den vorgegebenen Leerhub Δh zurücksteht, bis zum Anschlag in das Gehäuse 1 des Kraftstoffinjektors eingeschraubt, das heißt bis zur Anlage des Piezoaktorgehäuses 3 am Ausgleichsring 9, so befindet sich die Vorderkante des Piezoaktorgehäuses 3 genau auf der Höhe, die die Vorderseite der Vorspanneinrichtung hatte, als sich das Servoventil zu öffnen begann. Da demgegenüber im spannungslosen Zustand die Bodenplatte 4 des Piezoaktors 2 um den vorgegebenen Leerhub Δh zurücksteht, entspricht der Leerhub des Stellantriebs im Kraftstoffinjektor, das heißt das Spiel zwischen Bodenplatte 4 des Piezoaktors 2 und Servoventil, genau dem vorgegebenen Wert Δh.Finally, instead of the biasing device, the piezoelectric actuator 2, the bottom plate 4 as described above to the given idle stroke .DELTA.h lags, until it stops in the Screwed housing 1 of the fuel injector, that is until the piezoelectric actuator housing 3 abuts against the compensation ring 9, so the leading edge of the Piezoaktorgehäuses 3 is exactly at the height, the front of the pretensioner had when the servo valve began to open. In contrast in the de-energized state, the bottom plate 4 of the piezoelectric actuator 2 is set back by the given idle stroke Δh the idle stroke of the actuator in the fuel injector, that is the game between the bottom plate 4 of the piezoelectric actuator. 2 and servo valve, exactly the predetermined value Δh.

Bei einer alternativen Vorgehensweise wird der Piezoaktor 2 vor dem Einbau in das Injektorgehäuse 1 so bearbeitet, dass die Bodenplatte 4 und das Gehäuse 3 des Piezoaktors 2 im einbaufertigen Zustand, aber ohne anliegende Spannung plan geschliffen werden. Die Bodenplatte 4 des Piezoaktors 2 befindet sich somit nacht dem Schleifvorgang auf genau der gleichen Höhe wie das Gehäuse 3 des Piezoaktors 2. Dafür weist die Vorspanneinrichtung zur Verformung des Ausgleichsrings 9 keine plane Vorderseite, sondern eine Vorderseite auf, die an der oder den Stellen, an der oder denen die Vorspanneinrichtung auf das Übertragungselement 5 einwirkt, eine Erhebung der Höhe Δh besitzt.In an alternative approach, the piezoelectric actuator 2 before installation in the Injektorgehäuse 1 edited so that the bottom plate 4 and the housing 3 of the piezoelectric actuator 2 in the ready to install Condition, but ground without applied voltage become. The bottom plate 4 of the piezoelectric actuator 2 is located thus at night the grinding process on exactly the same Height as the housing 3 of the piezoelectric actuator 2 Biasing device for deformation of the compensation ring 9 no plane front but a front on that on the one or more locations at which or the biasing device acting on the transmission element 5, a survey the height Δh has.

Die zentrale Wirkfläche an der Vorspanneinrichtung, die mit dem Übertragungselement 5 in Eingriff kommt, steht mit anderen Worten in Einbaurichtung um den vorgegebenen Wert Δh für den Leerhub gegenüber der am Rand umlaufenden Wirkflache vor, die mit dem Ausgleichsring 9 in Eingriff kommt.The central effective surface on the pretensioner, with the transmission element 5 engages stands with others Words in installation direction by the predetermined value .DELTA.h for the idle stroke with respect to the circumferential effect on the edge, which engages with the balancing ring 9.

Die Vorspanneinrichtung wird wie bei der erstgenannten Ausführungsform anstelle des Piezoaktors 2 so weit in den Kraftstoffinjektor eingeschraubt, bis durch die Betätigung des Übertragungselements 5 durch den erhabenen Abschnitt an der Vorderseite der Vorspanneinrichtung das Ventilelement 7 des Servoventils zu öffnen beginnt. Der Ausgleichsring 9 wird dabei wie oben bleibend verformt. Anschließend wird statt der Vorspanneinrichtung der Piezoaktor 2, bei dem Gehäuse 3 und Bodenplatte 4 ohne anliegende Spannung plan geschliffen wurden, bis zum Anschlag am Ausgleichsring 9 in das Gehäuse 1 des Kraftstoffinjektors eingeschraubt.The pretensioner is the same as in the former embodiment instead of the piezoelectric actuator 2 so far in the Fuel injector screwed in until actuated of the transmission element 5 through the raised portion the front of the biasing device, the valve element. 7 of the servo valve begins to open. The balancing ring 9 is while remaining deformed as above. Subsequently, instead of the Biasing device of the piezoelectric actuator 2, in the housing 3 and Bottom plate 4 were ground without voltage applied, until it stops at the compensation ring 9 in the housing. 1 screwed the fuel injector.

Auch bei dieser Ausführungsform weist der Leerhub zwischen Piezoaktor 2 und Servoventil genau den vorgegebenen Wert Δh auf, da die Dicke des Ausgleichsrings 9 mit der Vorspanneinrichtung so eingestellt wird, dass sich beim Betrieb des Kraftstoffinjektors das Servoventil erst zu öffnen beginnt, nachdem die Bodenplatte 4 des Piezoaktors 2 bei dessen Ansteuerung den Leerweg Δh zurückgelegt hat.Also in this embodiment, the idle stroke between Piezo actuator 2 and servo valve exactly the predetermined value .DELTA.h on, since the thickness of the balancing ring 9 with the biasing means is adjusted so that during operation of the Fuel injector begins to open the servo valve after the bottom plate 4 of the piezoelectric actuator 2 in its control has covered the free travel Δh.

Claims (6)

Verfahren zum Positionieren des Stellantriebs in einem Kraftstoffinjektorgehäuse (1) mit einem Piezoaktor (2) und einem Stellglied (5, 6, 7), die miteinander in einer Wirkverbindung stehen, wobei der Piezoaktor (3) beweglich in einem Gehäuse (3) eingebracht ist und eine Bodenplatte 4 aufweist, die einer Öffnung des Gehäuses (3) zugeordnet ist, gekennzeichnet durch
ein Planschleifen von Gehäuse (3) und Bodenplatte (4) des Piezoaktors (2);
ein Vorsehen eines Ausgleichsrings (9) zwischen dem Kraftstoffinjektor (1) und einem Gehäuse (3) des Piezoaktors (2), der durch eine Vorspanneinrichtung mit einer Vorderseite, die eine zentrale Erhebung aufweist, die einem vorgegebenen Leerhub (Δh) entspricht, plastisch verformt wird, bis er eine Dicke hat, bei der sich das Stellglied (5, 6, 7) aufgrund der Einwirkung der erhabenen Vorderseite der Vorspanneinrichtung zu öffnen beginnt.Method for positioning the actuator in a fuel injector housing (1) with a piezoelectric actuator (2) and an actuator (5, 6, 7), which are in operative connection with each other, wherein the piezoelectric actuator (3) is movably incorporated in a housing (3) and a bottom plate 4, which is associated with an opening of the housing (3), characterized by
a surface grinding of housing (3) and bottom plate (4) of the piezoelectric actuator (2);
a provision of a balancing ring (9) between the fuel injector (1) and a housing (3) of the piezoactuator (2) plastically deformed by a biasing device having a front side having a central elevation corresponding to a predetermined idle stroke (Δh) until it has a thickness at which the actuator (5, 6, 7) begins to open due to the action of the raised front of the pretensioner. Vorrichtung zum Positionieren des Stellantriebs in einem Kraftstoffinjektorgehäuse (1) mit einem Piezoaktor (2) und einem Stellglied (5, 6, 7), die miteinander in einer Wirkverbindung stehen, wobei der Piezoaktor (2) beweglich in einem Gehäuse (3) eingebracht ist und eine Bodenplatte (4) aufweist, die einer Öffnung des Gehäuses (3) zugeordnet ist, gekennzeichnet durch
einer Einrichtung zum Planschleifen von Gehäuse (3) und Bodenplatte (4) des Piezoaktors (2); und
eine Vorspanneinrichtung mit einer Vorderseite mit einer zentralen Erhebung, die einen vorgegebenen Leerhub (Δh) entspricht, zum plastischen Verformen eines Ausgleichsrings (9) zwischen dem Kraftstoffinjektorgehäuse (1) und dem Gehäuse (3) des Piezoaktors (2) bis zu einer Dicke, bei der sich das Stellglied (5, 6, 7) aufgrund der Einwirkung der Vorderseite der Vorspanneinrichtung zu öffnen beginnt. Device for positioning the actuator in a fuel injector housing (1) with a piezoelectric actuator (2) and an actuator (5, 6, 7), which are in operative connection with each other, wherein the piezoelectric actuator (2) is movably incorporated in a housing (3) and a bottom plate (4) associated with an opening of the housing (3), characterized by
a device for surface grinding of housing (3) and bottom plate (4) of the piezoelectric actuator (2); and
biasing means having a front face with a central elevation corresponding to a given idle stroke (Δh) for plastically deforming a balancing ring (9) between the fuel injector housing (1) and the housing (3) of the piezoactuator (2) to a thickness the actuator (5, 6, 7) begins to open due to the action of the front of the biasing device. Vorrichtung nach Anspruch 2, dadurch gekennzeichnet, dass der Ausgleichsring (9) zwischen zwei Planflächen eingelegt wird und durch ein Zusammenrücken der zwei Flächen auf eine vorgegebene Dicke plastisch verformt wird.Apparatus according to claim 2, characterized in that the compensating ring (9) is inserted between two plane surfaces and is plastically deformed by a compression of the two surfaces to a predetermined thickness. Vorrichtung nach Anspruch 2 oder 3, dadurch gekennzeichnet, dass der Ausgleichsring (9) aus einem fließbaren Material besteht, wobei beim Zusammendrücken des Ausgleichsrings das Material des Ausgleichsrings fließend beginnt und dadurch dauerhaft plastisch verformt wird.Apparatus according to claim 2 or 3, characterized in that the compensating ring (9) consists of a flowable material, wherein upon compression of the balancing ring, the material of the balancing ring starts flowing and is thus permanently plastically deformed. Vorrichtung nach Anspruch 4, dadurch gekennzeichnet, dass der Ausgleichsring (9) aus Weicheisen oder aus einem Kupfer besteht.Apparatus according to claim 4, characterized in that the compensating ring (9) consists of soft iron or a copper. Kraftstoffinjektor mit einem Piezoaktor (2) und einem Stellglied (5, 6, 7), die miteinander in Wirkverbindung stehen, wobei der Piezoaktor (2) beweglich in einem Gehäuse (3) eingebracht ist und eine Bodenplatte (4) aufweist, die einer Öffnung des Gehäuses (3) zugeordnet ist,
dadurch gekennzeichnet, dass
die Bodenplatte (4) des Piezoaktors (2), die in der Wirkverbindung mit dem Stellglied (5, 6, 7) steht, im spannungslosen Zustand auf der Höhe der Vorderkante des Gehäuses (3) angeordnet ist und
ein Ausgleichsring (9) zwischen einem Kraftstoffinjektorgehäuse (1) und dem Gehäuse (3) des Piezoaktors (2) angeordnet und plastisch so verformt ist, dass das Stellglied (5, 6, 7) um einen vorgegebenen Leerhubabstand (Δh) von der Vorderkante des Ausgleichrings (9) zurückgesetzt ist.Fuel injector with a piezoelectric actuator (2) and an actuator (5, 6, 7), which are in operative connection with each other, wherein the piezoelectric actuator (2) is movably incorporated in a housing (3) and a bottom plate (4) having an opening associated with the housing (3),
characterized in that
the bottom plate (4) of the piezoelectric actuator (2), which is in operative connection with the actuator (5, 6, 7), is arranged in the de-energized state at the height of the front edge of the housing (3) and
a balancing ring (9) is arranged between a fuel injector housing (1) and the housing (3) of the piezoactuator (2) and plastically deformed such that the actuator (5, 6, 7) moves by a predetermined idle stroke distance (Δh) from the leading edge of the Balancing ring (9) is reset.
EP20040026927 1999-05-07 2000-05-04 Method of positioning an actuator of a fuel injector and apparatus to carry out the method Expired - Lifetime EP1505295B1 (en)

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DE19921242 1999-05-07
DE1999121242 DE19921242C1 (en) 1999-05-07 1999-05-07 Method of positioning control drive in common rail fuel injector for motor vehicle internal combustion engine
EP20000943547 EP1144841B1 (en) 1999-05-07 2000-05-04 Method for positioning the actuating drive in a fuel injector and device for implementing said method

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EP20000943547 Expired - Lifetime EP1144841B1 (en) 1999-05-07 2000-05-04 Method for positioning the actuating drive in a fuel injector and device for implementing said method

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US (3) US6705587B1 (en)
EP (2) EP1144841B1 (en)
DE (3) DE19921242C1 (en)
WO (1) WO2000068563A2 (en)

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WO2000068563A3 (en) 2001-07-19
DE50015988D1 (en) 2010-10-21
US20080011972A1 (en) 2008-01-17
US20040256499A1 (en) 2004-12-23
EP1144841A2 (en) 2001-10-17
US7310986B2 (en) 2007-12-25
EP1144841B1 (en) 2005-07-20
DE19921242C1 (en) 2000-10-26
US6705587B1 (en) 2004-03-16
DE50010750D1 (en) 2005-08-25
US8720852B2 (en) 2014-05-13
EP1505295B1 (en) 2010-09-08
WO2000068563A2 (en) 2000-11-16

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