EP1865195B1 - Device for injecting fuel - Google Patents

Device for injecting fuel Download PDF

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Publication number
EP1865195B1
EP1865195B1 EP07106972A EP07106972A EP1865195B1 EP 1865195 B1 EP1865195 B1 EP 1865195B1 EP 07106972 A EP07106972 A EP 07106972A EP 07106972 A EP07106972 A EP 07106972A EP 1865195 B1 EP1865195 B1 EP 1865195B1
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EP
European Patent Office
Prior art keywords
actuator
housing part
upper housing
valve member
control valve
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.)
Not-in-force
Application number
EP07106972A
Other languages
German (de)
French (fr)
Other versions
EP1865195A1 (en
Inventor
Friedrich Boecking
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
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Filing date
Publication date
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Publication of EP1865195A1 publication Critical patent/EP1865195A1/en
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Publication of EP1865195B1 publication Critical patent/EP1865195B1/en
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    • 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
    • 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
    • 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
    • F02M2547/00—Special features for fuel-injection valves actuated by fluid pressure
    • F02M2547/003—Valve inserts containing control chamber and valve piston
    • 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

Definitions

  • the invention relates to a device for injecting fuel into a combustion chamber of an internal combustion engine according to the preamble of claim 1.
  • the fuel injector generally comprises a control valve, which is designed as a solenoid valve or is actuated with a piezoelectric actuator.
  • Fuel injectors operated with a piezo actuator distinguish between inverse and non-inverse operated injectors. With inversely operated injectors fuel is injected into the combustion chamber, as long as the piezoelectric actuator is not energized. To stop the injection process, the piezoelectric actuator is energized again and expands with it. In non-inversely controlled fuel injectors, the injection process is started when the actuator is energized.
  • the control valve In non-inversely controlled fuel injectors, which are operated with a piezoelectric actuator, the control valve is generally designed so that this opens when the piezoelectric actuator is energized and expands.
  • the piezoelectric actuator acts either directly or hydraulically translated to the valve member of the control valve. The hydraulic ratio is necessary to achieve an additional stroke in short-built actuators to open the control valve far enough.
  • a directly controlled fuel injector with piezoelectric actuator is for example off DE-A 103 37 875 known.
  • a device for injecting fuel into a combustion chamber of an internal combustion engine in which the control valve for driving an injection valve member is driven by a piezoelectric actuator.
  • the piezoelectric actuator is enclosed by a housing part and supported against the housing part.
  • the control valve has a valve member which is connected to the housing part.
  • the housing part, on which the piezoelectric actuator is supported, is fixed by means of an electromagnetic fastening element within a cavity of an injector housing.
  • a control valve for actuating an injection valve member is operated with an actuator which expands when power is supplied.
  • the actuator When the actuator is energized, the control valve is opened and closed when the actuator is not energized.
  • the actuator is enclosed by an upper housing part, which is axially displaceable relative to the injector housing and which is connected to a valve member of the control valve.
  • the upper housing part is mounted with bolts on the valve member. The bolts are passed through a plate which is fixedly connected to the injector housing and on which the actuator is supported. By the bolts, with which the upper housing part is connected to the valve member, the valve member is moved in the direction of the actuator, as soon as it expands.
  • the closing element connected to the valve member is lifted from its seat and releases a connection from a control chamber to a fuel return.
  • the piezoelectric actuator is energized to start the injection process and thereby expands.
  • the upper housing part which is axially displaceable in the injector is displaced upwards.
  • the valve member connected to the upper housing part opens the control valve by lifting a closing element out of its seat.
  • the upper housing part is enclosed in a preferred embodiment of a cover which is connected to the injector.
  • a cover is a plastic or metal cap, which is connected to the injector.
  • the connection of the cover with the injector can be done, for example, that on the cover a bead is provided, which is screwed with a clamping nut on the injector.
  • a membrane is preferably received, by which the actuator is sealed against fuel.
  • the membrane is designed so that it does not hinder the opening and closing movement of the valve member.
  • the membrane is preferably fluid-tightly connected both to the housing and to the valve member.
  • the diaphragm is received between an upper portion and a lower portion of the valve member.
  • the membrane may be made of a resilient material.
  • the opening and closing movement of the valve member is then assisted by the spring force of the diaphragm.
  • a shim is preferably provided between a closing element holder on the valve member. The stroke is set by the thickness of the shim.
  • the actuator with a top bracket is positively secured to the upper housing part.
  • the movement of the actuator is transmitted directly to the upper housing part.
  • the upper holder of the actuator is not connected to the upper housing part and between the upper holder and the upper housing part, a gap is formed. This gap forms a forward stroke, by which an optionally occurring lifting error can be compensated.
  • the spring element In order to achieve a return movement of the closing element into its seat when the upper holder is not connected to the upper housing part, in this case between the upper housing part and the cover a spring element regardingnommnen, which is supported on the one hand on the upper housing part and on the other hand on the cover ,
  • the spring element surrounds the upper housing part and is supported on a rib on the upper housing part.
  • the spring element is for example designed as a helical spring compression spring.
  • a plate spring or a leaf spring can be used.
  • Advantage of the use of a plate spring or a leaf spring is that the space between the upper housing part and the cover kept small can be. This is also the case when the spring element encloses the upper housing part.
  • the upper housing part is preferably made of Invar.
  • Invar has a coefficient of thermal expansion, which corresponds approximately to that of a piezoelectric actuator.
  • FIG. 1 shows a control valve of an inventively designed fuel injector in a first embodiment.
  • An inventively designed device for injecting fuel into a combustion chamber of an internal combustion engine comprises a control valve 1, which is actuated by an actuator 2, which expands when power is supplied.
  • the actuator 2 is a piezoelectric actuator.
  • the actuator 2 is clamped between an upper holder 3 and a lower holder 4.
  • the required bias of the actuator 2 is achieved by a spring element 5.
  • the spring element 5 is in the embodiment shown here designed as a tension spring tube spring which surrounds the actuator 2 and is connected to the upper bracket 3 and the lower bracket 4.
  • the upper bracket 3 is in the in FIG. 1 embodiment shown positively connected to an upper housing part 6.
  • the positive connection takes place in the embodiment shown here by welding. In addition to the positive connection by welding, but it would also be conceivable that the upper bracket is connected by gluing or soldering or by a non-positive connection with the upper housing part 6. Suitable frictional connections are, for example, press-fitting or screwing.
  • the lower holder 4 is connected to a plate 7, which is dimensionally stable connected to the injector 8.
  • the lower bracket 4 is fixed to the plate 7 by a positive connection.
  • openings 9 are formed, are guided by the bolts 10 which are connected to the upper housing part 6.
  • the bolts 10 are connected to an upper portion 11 of a valve member 12.
  • the upper portion 11 of the valve member 12 is designed in the form of a valve pin an armature group of a magnet assembly.
  • the design of the upper portion 11 in the form of an armature of a solenoid valve assembly also makes it possible to easily connect the bolts 10, which are connected to the upper housing part 6, with the upper portion 11 of the valve member 12.
  • the upper portion 11 of the valve member 12 via threaded rods or pins (not according to the invention) are connected to the upper housing part 6.
  • the upper housing part 6 is enclosed by a cover 13.
  • the cover 13 is provided in the embodiment shown here with a bead 14. With a clamping nut 15 which engages over the bead 14, the cover 13 is connected to the injector 8.
  • the membrane 16 is liquid-tightly connected to the plate 7.
  • the connection is made for example via a weld.
  • the membrane 16 is performed under the upper portion of the valve member 12.
  • the membrane 16 may also be provided with an opening which surrounds the valve member 12. Around Opening the membrane 16 is liquid-tightly connected to the valve member 12.
  • the connection is then preferably via a weld.
  • a lower portion 17 of the valve member 12 connects.
  • the lower section 17 comprises a dial 18, a closing element receptacle 19 and a closing element 20.
  • the closing element 20 is of spherical design here.
  • the closing element 20 may also be formed, for example, conical or in the form of a flat seat.
  • the closing element 20 When the control valve 1 is closed, the closing element 20 is in a seat 21.
  • the control valve 1 closes or releases a drainage channel 22 with an outlet throttle 23 received therein.
  • the outlet channel 22 connects a control chamber 24 with a fuel return 25.
  • the control chamber 24 is bounded on one side by an upper end face 26 of a control piston 27.
  • the control chamber 24 is connected to a fuel inlet 29.
  • the fuel inlet 29 is connected, for example, to a high-pressure accumulator, not shown here, from which fuel under system pressure flows into the fuel injector. From the fuel inlet 29 branches off a high pressure passage 30 which is connected to a nozzle chamber. From the nozzle chamber, when the injection valve member is open, the fuel flows into the combustion chamber of the internal combustion engine.
  • the outlet channel 22 with the outlet throttle 23, the inlet throttle 28, the control chamber 24 and a guide 31 for the control piston 27 are formed in a valve piece 32. Furthermore, the seat 21 of the control valve 1 is formed in the valve piece.
  • the actuation of the actuator 2 via an electrical contact 33 is guided here by the plate 7 so that it is stationary and is not moved with the upper housing part 6.
  • the actuator 2 is energized. As a result, the actuator 2 expands. Since the lower holder 4 is received with the plate 7 stationary in the injector 8, the actuator 2 acts on the upper bracket 3 and thus on the upper housing part 6. This is raised. This also raises the upper portion 11 of the valve member 12 which is connected to the upper housing part 6 at. As a result, the closing element 20 also lifts out of its seat and releases the connection from the outlet channel 22 into the fuel return 25. Fuel flows from the control chamber 24 into the fuel return 25. As a result, the pressure in the control chamber 24 decreases. The Compressive force acting on the upper end surface 26 of the control piston 27, thereby becomes smaller. The control piston is no longer force-balanced and moves into the control chamber 24.
  • control chamber This increases the volume of a control chamber, not shown here, which is bounded by the end of the control piston 24, which is opposite to the upper end surface 26.
  • the second control chamber is further limited by an injection valve member. Due to the decreasing pressure, a lower pressure force acts on the injection valve member, so that this is lifted from its seat. The injection process begins.
  • FIG. 2 shows a section of a inventively designed fuel injector in a second embodiment.
  • the upper bracket 3 of the actuator 2 is not connected to the upper housing part 6.
  • the upper housing part 6 can be raised by the actuator 2 and the upper bracket 3, a shoulder 40 is formed on the upper bracket 3.
  • the shoulder 40 cooperates with a second shoulder 41 on the upper housing part 6.
  • the actuator 2 is energized and expands, the upper housing part 3 rises in the direction of the upper housing part 6.
  • the shoulder 40 of the upper bracket 3 is in contact with the second shoulder 41 of the upper housing part 6, the upper housing part 6 is raised.
  • a gap 42 is formed between the shoulder 40 of the upper bracket 3 and the second shoulder 41 of the upper housing part 6.
  • the gap 42 serves as a forward stroke, with which an optionally occurring lifting error can be compensated. This is the case, for example, if the piezoelectric actuator, if it is not energized, contracts further if the upper housing part can be moved in the direction of the control valve 1.
  • the upper housing part 6 is enclosed by a cover 13.
  • the cover 13 is fixedly connected to the injector 8.
  • the actuator 2 contracts the upper housing part 6 to move down again so that the control valve 1 is closed, encloses in the embodiment shown here, a spring element 43, the upper housing part 6.
  • the spring element 43 is in the embodiment shown here designed as a helical spring compression spring. So that the upper housing part 6 is moved in not energized actuator 2 in the direction of the control valve 1, the spring element 43 is supported with one side against the cover 13 and with the other side against an extension 44 on the upper housing part.
  • the spring element 43 is tensioned.
  • the spring force of the spring element 43 acts on the extension 44 of the movable upper housing part 6 and pushes it down.
  • the control valve 1 is closed by the closing element 20 is placed in its seat 21.
  • the cover 13 in the in FIG. 2 illustrated embodiment is fixedly connected to the injector, so that they can not move.
  • the spring element 43 is already biased even when not energized and thus not extended actuator 2.
  • the selected bias voltage is dependent on the force that is to act on the extension 44 on the upper housing part 6.

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

Abstract

A control valve (1) is operated so as to trigger a fuel injection valve element with an actuator (2), which expands during flow supply. When the actuator is supplied with a flow, the control valve is opened. When the actuator is not supplied with a flow, the control valve is closed. The actuator is enclosed by an upper casing part (6) linked to a valve element (12) in the control valve.

Description

Die Erfindung betrifft eine Vorrichtung zum Einspritzen von Kraftstoff in einen Brennraum einer Verbrennungskraftmaschine gemäß dem Oberbegriff von Anspruch 1.The invention relates to a device for injecting fuel into a combustion chamber of an internal combustion engine according to the preamble of claim 1.

Stand der TechnikState of the art

Üblicherweise werden Kraftstoffinjektoren elektrisch angesteuert. Hierzu umfasst der Kraftstoffinjektor im Allgemeinen ein Steuerventil, welches als Magnetventil ausgebildet ist oder mit einem Piezoaktor betätigt wird. Bei Kraftstoffinjektoren, die mit einem Piezoaktor betätigt werden, wird zwischen invers und nicht-invers betriebenen Injektoren unterschieden. Bei invers betriebenen Injektoren wird Kraftstoff in den Brennraum eingespritzt, solange der Piezoaktor nicht bestromt ist. Um den Einspritzvorgang zu beenden, wird der Piezoaktor wieder bestromt und dehnt sich damit aus. Bei nicht-invers angesteuerten Kraftstoffinjektoren wird der Einspritzvorgang gestartet, wenn der Aktor bestromt wird. Bei nicht-invers angesteuerten Kraftstoffinjektoren, die mit einem Piezoaktor betrieben werden, ist das Steuerventil im Allgemeinen so ausgebildet, dass dieses öffnet, wenn der Piezoaktor bestromt wird und sich ausdehnt. Hierbei wirkt der Piezoaktor entweder direkt oder hydraulisch übersetzt auf das Ventilglied des Steuerventils. Die hydraulische Übersetzung ist notwendig, um bei kurz gebauten Aktoren einen zusätzlichen Hub zu erreichen, um das Steuerventil weit genug öffnen zu können. Ein solcher direkt gesteuerter Kraftstoff-injektor mit Piezoaktor ist zum Beispiel aus DE-A 103 37 875 bekannt.Usually fuel injectors are electrically controlled. For this purpose, the fuel injector generally comprises a control valve, which is designed as a solenoid valve or is actuated with a piezoelectric actuator. Fuel injectors operated with a piezo actuator distinguish between inverse and non-inverse operated injectors. With inversely operated injectors fuel is injected into the combustion chamber, as long as the piezoelectric actuator is not energized. To stop the injection process, the piezoelectric actuator is energized again and expands with it. In non-inversely controlled fuel injectors, the injection process is started when the actuator is energized. In non-inversely controlled fuel injectors, which are operated with a piezoelectric actuator, the control valve is generally designed so that this opens when the piezoelectric actuator is energized and expands. Here, the piezoelectric actuator acts either directly or hydraulically translated to the valve member of the control valve. The hydraulic ratio is necessary to achieve an additional stroke in short-built actuators to open the control valve far enough. Such a directly controlled fuel injector with piezoelectric actuator is for example off DE-A 103 37 875 known.

Aus EP 1167 748 A2 ist eine Vorrichtung zum Einspritzen von Kraftstoff in einen Brennraum einer Brennkraftmaschine bekannt, bei der das Steuerventil zum Ansteuern eines Einspritzventilglieds von einem Piezoaktor angesteuert wird. Der Piezoaktor ist von einem Gehäuseteil umschlossen und gegen das Gehäuseteil abgestützt ist. Das Steuerventil weist ein Ventilglied auf, das mit dem Gehäuseteil verbunden ist. Das Gehäuseteil, an dem sich der Piezoaktor abstützt, ist mittels eines elektromagnetischen Befestigungselements innerhalb eines Hohlraums eines Injektorgehäuse fixiert.Out EP 1167 748 A2 a device for injecting fuel into a combustion chamber of an internal combustion engine is known, in which the control valve for driving an injection valve member is driven by a piezoelectric actuator. The piezoelectric actuator is enclosed by a housing part and supported against the housing part. The control valve has a valve member which is connected to the housing part. The housing part, on which the piezoelectric actuator is supported, is fixed by means of an electromagnetic fastening element within a cavity of an injector housing.

Offenbarung der ErfindungDisclosure of the invention

Bei einer erfindungsgemäßen Vorrichtung zum Einspritzen von Kraftstoff in einen Brennraum einer Verbrennungskraftmaschine wird ein Steuerventil zum Ansteuern eines Einspritzventilgliedes mit einem Aktor betrieben, der sich bei Stromzufuhr ausdehnt. Bei bestromtem Aktor wird das Steuerventil geöffnet und bei nicht bestromtem Aktor geschlossen. Der Aktor ist von einem oberen Gehäuseteil umschlossen, welches gegenüber dem Injektorgehäuse axial verschiebbar ist und das mit einem Ventilglied des Steuerventils verbunden ist. Das obere Gehäuseteil wird mit Bolzen am Ventilglied montiert. Die Bolzen sind durch eine Platte geführt, die mit dem Injektorgehäuse fest , verbunden ist und auf der sich der Aktor abstützt. Durch die Bolzen, mit denen das obere Gehäuseteil mit dem Ventilglied verbunden ist, wird das Ventilglied in Richtung des Aktors bewegt, sobald dieser sich ausdehnt. Das mit dem Ventilglied verbundene Schließelement wird aus seinem Sitz gehoben und gibt eine Verbindung von einem Steuerraum zu einem Kraftstoffrücklauf frei. Im Betrieb wird zum Starten des Einspritzvorganges der Piezoaktor bestromt und dehnt sich dadurch aus. Hierdurch wird das obere Gehäuseteil, welches im Injektorgehäuse axial verschiebbar ist nach oben verschoben. Das mit dem oberen Gehäuseteil verbundene Ventilglied öffnet das Steuerventil, indem ein Schließelement aus seinem Sitz gehoben wird. Hierdurch ist es möglich, einen Kraftstoffinjektor, der üblicherweise mit einem Magnetventil betrieben wird, mit einem Piezoaktor zu betreiben, indem die Magnetbaugruppe durch den Piezoaktor mit dem oberen Gehäuseteil ausgetauscht wird, ohne dass weitere konstruktive Änderungen am Injektor erforderlich sind.In a device according to the invention for injecting fuel into a combustion chamber of an internal combustion engine, a control valve for actuating an injection valve member is operated with an actuator which expands when power is supplied. When the actuator is energized, the control valve is opened and closed when the actuator is not energized. The actuator is enclosed by an upper housing part, which is axially displaceable relative to the injector housing and which is connected to a valve member of the control valve. The upper housing part is mounted with bolts on the valve member. The bolts are passed through a plate which is fixedly connected to the injector housing and on which the actuator is supported. By the bolts, with which the upper housing part is connected to the valve member, the valve member is moved in the direction of the actuator, as soon as it expands. The closing element connected to the valve member is lifted from its seat and releases a connection from a control chamber to a fuel return. In operation, the piezoelectric actuator is energized to start the injection process and thereby expands. As a result, the upper housing part, which is axially displaceable in the injector is displaced upwards. The valve member connected to the upper housing part opens the control valve by lifting a closing element out of its seat. This makes it possible to operate a fuel injector, which is usually operated with a solenoid valve, with a piezoelectric actuator by the magnet assembly is replaced by the piezoelectric actuator with the upper housing part, without further structural changes to the injector are required.

Damit im laufenden Betrieb keine sich bewegenden Teile aus dem Aktor herausragen, ist das obere Gehäuseteil in einer bevorzugten Ausführungsform von einer Abdeckung umschlossen, die mit dem Injektorgehäuse verbunden ist. Als Abdeckung eignet sich eine Kunststoff- oder Metallkappe, die mit dem Injektor verbunden wird. Die Verbindung der Abdeckung mit dem Injektor kann zum Beispiel dadurch erfolgen, dass an der Abdeckung ein Bördelrand vorgesehen ist, welcher mit einer Spannmutter auf dem Injektorgehäuse festgeschraubt wird. Daneben ist es aber auch möglich, die Abdeckung unlösbar mit dem Injektorgehäuse zum Beispiel durch Schweißen oder Kleben zu verbinden.So that during operation no moving parts protrude from the actuator, the upper housing part is enclosed in a preferred embodiment of a cover which is connected to the injector. As a cover is a plastic or metal cap, which is connected to the injector. The connection of the cover with the injector can be done, for example, that on the cover a bead is provided, which is screwed with a clamping nut on the injector. In addition, however, it is also possible to permanently connect the cover to the injector housing, for example by welding or gluing.

Zwischen dem Aktor und dem mit dem Ventilglied verbundenen Schließelement ist vorzugsweise eine Membran aufgenommen, durch die der Aktor gegen Kraftstoff abgedichtet wird. Die Membran ist dabei so ausgebildet, dass durch diese die Öffnungs-und Schließbewegung des Ventilgliedes nicht behindert wird. Um den Aktor wirksam gegen Kraftstoff abzudichten, wird die Membran vorzugsweise sowohl mit dem Gehäuse als auch mit dem Ventilglied flüssigkeitsdicht verbunden. In einer Ausführungsform ist die Membran zwischen einem oberen Abschnitt und einem unteren Abschnitt des Ventilgliedes aufgenommen.Between the actuator and the closing element connected to the valve member, a membrane is preferably received, by which the actuator is sealed against fuel. The membrane is designed so that it does not hinder the opening and closing movement of the valve member. In order to effectively seal the actuator against fuel, the membrane is preferably fluid-tightly connected both to the housing and to the valve member. In one embodiment the diaphragm is received between an upper portion and a lower portion of the valve member.

Um die Öffnungsbewegungen des Steuerventiles zu unterstützen, kann die Membran aus einem federelastischen Material gefertigt sein. Die Öffnungs- und Schließbewegung des Ventilgliedes wird dann durch die Federkraft der Membran unterstützt. Zum Einstellen des Hubes ist vorzugsweise zwischen einer Schließelementhalterung am Ventilglied eine Einstellscheibe vorgesehen. Der Hub wird eingestellt durch die Dicke der Einstellscheibe.In order to support the opening movements of the control valve, the membrane may be made of a resilient material. The opening and closing movement of the valve member is then assisted by the spring force of the diaphragm. For adjusting the stroke, a shim is preferably provided between a closing element holder on the valve member. The stroke is set by the thickness of the shim.

In einer Ausführungsform ist der Aktor mit einer oberen Halterung formschlüssig am oberen Gehäuseteil befestigt. In diesem Fall wird die Bewegung des Aktors direkt auf das obere Gehäuseteil übertragen. In einer alternativen Ausführungsform ist die obere Halterung des Aktors nicht mit dem oberen Gehäuseteil verbunden und zwischen der oberen Halterung und dem oberen Gehäuseteil ist ein Spalt ausgebildet. Dieser Spalt bildet einen Vorhub, durch den ein gegebenenfalls auftretender Hubfehler ausgeglichen werden kann. Um eine Rückstellbewegung des Schließelementes in seinen Sitz zu erzielen, wenn die obere Halterung nicht mit dem oberen Gehäuseteil verbunden ist, ist in diesem Fall zwischen dem oberen Gehäuseteil und der Abdeckung ein Federelement aufgenommnen, welches sich einerseits am oberen Gehäuseteil und andererseits an der Abdeckung abstützt. Vorzugsweise umschließt das Federelement das obere Gehäuseteil und stützt sich auf eine Rippe am oberen Gehäuseteil ab. Das Federelement ist zum Beispiel eine als Spiralfeder ausgebildete Druckfeder. Wenn sich das Federelement zwischen dem oberen Gehäuseteil und der Abdeckung befindet und auf die obere Stirnfläche des oberen Gehäuseteils wirkt, ist zum Beispiel auch eine Tellerfeder oder eine Blattfeder einsetzbar. Vorteil des Einsatzes einer Tellerfeder oder einer Blattfeder ist, dass der Bauraum zwischen dem oberen Gehäuseteil und der Abdeckung klein gehalten werden kann. Dies ist ebenfalls der Fall, wenn das Federelement das obere Gehäuseteil umschließt.In one embodiment, the actuator with a top bracket is positively secured to the upper housing part. In this case, the movement of the actuator is transmitted directly to the upper housing part. In an alternative embodiment, the upper holder of the actuator is not connected to the upper housing part and between the upper holder and the upper housing part, a gap is formed. This gap forms a forward stroke, by which an optionally occurring lifting error can be compensated. In order to achieve a return movement of the closing element into its seat when the upper holder is not connected to the upper housing part, in this case between the upper housing part and the cover a spring element aufgenommnen, which is supported on the one hand on the upper housing part and on the other hand on the cover , Preferably, the spring element surrounds the upper housing part and is supported on a rib on the upper housing part. The spring element is for example designed as a helical spring compression spring. When the spring element is located between the upper housing part and the cover and acts on the upper end face of the upper housing part, for example, a plate spring or a leaf spring can be used. Advantage of the use of a plate spring or a leaf spring is that the space between the upper housing part and the cover kept small can be. This is also the case when the spring element encloses the upper housing part.

Damit sich der Piezoaktor und das obere Gehäuseteil durch Erwärmung oder Abkühlung nicht unterschiedlich stark ausdehnen, ist das obere Gehäuseteil vorzugsweise aus Invar gefertigt. Vorteil von Invar ist, dass dieses einen Temperaturausdehnungskoeffizienten hat, der in etwa dem eines Piezoaktors entspricht.So that the piezoelectric actuator and the upper housing part do not expand to different extents due to heating or cooling, the upper housing part is preferably made of Invar. Advantage of Invar is that this has a coefficient of thermal expansion, which corresponds approximately to that of a piezoelectric actuator.

Kurze Beschreibung der ZeichnungenBrief description of the drawings

Ausführungsbeispiele der Erfindung sind in den Zeichnungen dargestellt und in der nachfolgenden Beschreibung näher erläutert.Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description.

Es zeigen:

  • Figur 1 ein erfindungsgemäß ausgebildetes Steuerventil eines Kraftstoffinjektors,
  • Figur 2 einen Ausschnitt aus einem oberen Gehäuseteil und einer Abdeckung in einer zweiten Ausführungsform.
Show it:
  • FIG. 1 an inventively designed control valve of a fuel injector,
  • FIG. 2 a section of an upper housing part and a cover in a second embodiment.

Ausführungsformen der ErfindungEmbodiments of the invention

Figur 1 zeigt ein Steuerventil eines erfindungsgemäß ausgebildeten Kraftstoffinjektors in einer ersten Ausführungsform. FIG. 1 shows a control valve of an inventively designed fuel injector in a first embodiment.

Eine erfindungsgemäß ausgebildete Vorrichtung zum Einspritzen von Brennstoff in einen Brennraum einer Verbrennungskraftmaschine umfasst ein Steuerventil 1, welches durch einen Aktor 2 betätigt wird, der sich bei Stromzufuhr ausdehnt. In der hier dargestellten Ausführungsform ist der Aktor 2 ein Piezoaktor. Der Aktor 2 ist zwischen einer oberen Halterung 3 und einer unteren Halterung 4 eingespannt. Die erforderliche Vorspannung des Aktors 2 wird durch ein Federelement 5 erzielt. Das Federelement 5 ist in der hier dargestellten Ausführungsform eine als Zugfeder ausgebildete Rohrfeder, die den Aktor 2 umschließt und mit der oberen Halterung 3 und der unteren Halterung 4 verbunden ist. Die obere Halterung 3 ist in der in Figur 1 dargestellten Ausführungsform formschlüssig mit einem oberen Gehäuseteil 6 verbunden. Die formschlüssige Verbindung erfolgt in der hier dargestellten Ausführungsform durch Verschweißen. Neben der formschlüssigen Verbindung durch Verschweißen wäre es aber auch denkbar, dass die obere Halterung durch Kleben oder Löten bzw. durch eine kraftschlüssige Verbindung mit dem oberen Gehäuseteil 6 verbunden wird. Geeignete kraftschlüssige Verbindungen sind zum Beispiel Einpressen oder Einschrauben.An inventively designed device for injecting fuel into a combustion chamber of an internal combustion engine comprises a control valve 1, which is actuated by an actuator 2, which expands when power is supplied. In the embodiment shown here, the actuator 2 is a piezoelectric actuator. The actuator 2 is clamped between an upper holder 3 and a lower holder 4. The required bias of the actuator 2 is achieved by a spring element 5. The spring element 5 is in the embodiment shown here designed as a tension spring tube spring which surrounds the actuator 2 and is connected to the upper bracket 3 and the lower bracket 4. The upper bracket 3 is in the in FIG. 1 embodiment shown positively connected to an upper housing part 6. The positive connection takes place in the embodiment shown here by welding. In addition to the positive connection by welding, but it would also be conceivable that the upper bracket is connected by gluing or soldering or by a non-positive connection with the upper housing part 6. Suitable frictional connections are, for example, press-fitting or screwing.

Die untere Halterung 4 ist mit einer Platte 7 verbunden, die formstabil mit dem Injektorgehäuse 8 verbunden ist. In der hier dargestellten Ausführungsform ist die untere Halterung 4 mit der Platte 7 durch eine formschlüssige Verbindung befestigt. In der Platte 7 sind Durchbrüche 9 ausgebildet, durch die Bolzen 10 geführt sind, die mit dem oberen Gehäuseteil 6 verbunden sind. Die Bolzen 10 sind mit einem oberen Abschnitt 11 eines Ventilgliedes 12 verbunden.The lower holder 4 is connected to a plate 7, which is dimensionally stable connected to the injector 8. In the embodiment shown here, the lower bracket 4 is fixed to the plate 7 by a positive connection. In the plate 7 openings 9 are formed, are guided by the bolts 10 which are connected to the upper housing part 6. The bolts 10 are connected to an upper portion 11 of a valve member 12.

Um den Aktor 2 anstelle einer Magnetbaugruppe in einem Kraftstoffinjektor gleicher Bauart einsetzen zu können, ist der obere Abschnitt 11 des Ventilglieds 12 in Form eines Ventilbolzens einer Ankergruppe einer Magnetbaugruppe ausgeführt. Die Gestaltung des oberen Abschnittes 11 in Form eines Ankers einer Magnetventilbaugruppe ermöglicht es auch, auf einfache Weise die Bolzen 10, die mit dem oberen Gehäuseteil 6 verbunden sind, mit dem oberen Abschnitt 11 des Ventilgliedes 12 zu verbinden.In order to use the actuator 2 instead of a magnet assembly in a fuel injector of the same type, the upper portion 11 of the valve member 12 is designed in the form of a valve pin an armature group of a magnet assembly. The design of the upper portion 11 in the form of an armature of a solenoid valve assembly also makes it possible to easily connect the bolts 10, which are connected to the upper housing part 6, with the upper portion 11 of the valve member 12.

Anstelle der Bolzen 10 kann der obere Abschnitt 11 des Ventilgliedes 12 auch über Gewindestangen oder Zapfen (jeweils nicht erfindungsgemäß) mit dem oberen Gehäuseteil 6 verbunden werden.Instead of the bolt 10, the upper portion 11 of the valve member 12 via threaded rods or pins (not according to the invention) are connected to the upper housing part 6.

Um den Aktor 2 gegen die Umwelt abzudichten und um zu vermieden, dass sich bewegende Teile aus dem Kraftstoffinjektor herausragen, ist das obere Gehäuseteil 6 von einer Abdeckung 13 umschlossen. Die Abdeckung 13 ist in der hier dargestellten Ausführungsform mit einem Bördelrand 14 versehen. Mit einer Spannmutter 15, die über den Bördelrand 14 greift ist die Abdeckung 13 mit dem Injektorgehäuse 8 verbunden.In order to seal the actuator 2 against the environment and to avoid that moving parts protrude from the fuel injector, the upper housing part 6 is enclosed by a cover 13. The cover 13 is provided in the embodiment shown here with a bead 14. With a clamping nut 15 which engages over the bead 14, the cover 13 is connected to the injector 8.

Eine Abdichtung des Aktors 2 gegenüber dem im Injektor enthaltenen Kraftstoff erfolgt über eine Membran 16. In der hier dargestellten Ausführungsform ist die Membran 16 flüssigkeitsdicht mit der Platte 7 verbunden. Die Verbindung erfolgt zum Beispiel über eine Schweißnaht. In der hier dargestellten Ausführungsform ist die Membran 16 unter dem oberen Abschnitt des Ventilgliedes 12 durchgeführt. Die Membran 16 kann aber auch mit einer Öffnung versehen sein, die das Ventilglied 12 umschließt. Im Bereich der Öffnung wird die Membran 16 mit dem Ventilglied 12 flüssigkeitsdicht verbunden. Die Verbindung erfolgt dann vorzugsweise über eine Schweißnaht. An die Membran 16 schließt sich ein unterer Abschnitt 17 des Ventilgliedes 12 an. Der untere Abschnitt 17 umfasst eine Einstellscheibe 18, eine Schließelementaufnahme 19 und ein Schließelement 20. Das Schließelement 20 ist hier kugelförmig ausgebildet. Anstatt kugelförmig kann das Schließelement 20 aber auch zum Beispiel kegelförmig oder in Form eines Flachsitzes ausgebildet sein. Bei verschlossenem Steuerventil 1 steht das Schließelement 20 in einem Sitz 21. Durch das Steuerventil 1 ist ein Ablaufkanal 22 mit einer darin aufgenommenen Ablaufdrossel 23 verschließbar oder freigebbar. Der Ablaufkanal 22 verbindet einen Steuerraum 24 mit einem Kraftstoffrücklauf 25. Der Steuerraum 24 ist an einer Seite durch eine obere Stirnfläche 26 eines Steuerkolbens 27 begrenzt. Über eine Zulaufdrossel 28 ist der Steuerraum 24 mit einem Kraftstoffzulauf 29 verbunden. Der Kraftstoffzulauf 29 ist zum Beispiel mit einem hier nicht dargestellten Hochdruckspeicher verbunden, aus welchem unter Systemdruck stehender Kraftstoff in den Kraftstoffinjektor strömt. Vom Kraftstoffzulauf 29 zweigt ein Hochdruckkanal 30 ab, der mit einem Düsenraum verbunden ist. Aus dem Düsenraum strömt bei geöffnetem Einspritzventilglied der Kraftstoff in den Brennraum der Verbrennungskraftmaschine.A seal of the actuator 2 with respect to the fuel contained in the injector via a membrane 16. In the embodiment shown here, the membrane 16 is liquid-tightly connected to the plate 7. The connection is made for example via a weld. In the embodiment shown here, the membrane 16 is performed under the upper portion of the valve member 12. The membrane 16 may also be provided with an opening which surrounds the valve member 12. Around Opening the membrane 16 is liquid-tightly connected to the valve member 12. The connection is then preferably via a weld. To the membrane 16, a lower portion 17 of the valve member 12 connects. The lower section 17 comprises a dial 18, a closing element receptacle 19 and a closing element 20. The closing element 20 is of spherical design here. But instead of spherical, the closing element 20 may also be formed, for example, conical or in the form of a flat seat. When the control valve 1 is closed, the closing element 20 is in a seat 21. The control valve 1 closes or releases a drainage channel 22 with an outlet throttle 23 received therein. The outlet channel 22 connects a control chamber 24 with a fuel return 25. The control chamber 24 is bounded on one side by an upper end face 26 of a control piston 27. Via an inlet throttle 28, the control chamber 24 is connected to a fuel inlet 29. The fuel inlet 29 is connected, for example, to a high-pressure accumulator, not shown here, from which fuel under system pressure flows into the fuel injector. From the fuel inlet 29 branches off a high pressure passage 30 which is connected to a nozzle chamber. From the nozzle chamber, when the injection valve member is open, the fuel flows into the combustion chamber of the internal combustion engine.

Um den Kraftstoffinjektor montieren zu können, sind in der hier dargestellten Ausführungsform der Ablaufkanal 22 mit der Ablaufdrossel 23, die Zulaufdrossel 28, der Steuerraum 24 und eine Führung 31 für den Steuerkolben 27 in einem Ventilstück 32 ausgebildet. Weiterhin ist auch der Sitz 21 des Steuerventils 1 im Ventilstück ausgebildet.In order to be able to mount the fuel injector, in the embodiment shown here, the outlet channel 22 with the outlet throttle 23, the inlet throttle 28, the control chamber 24 and a guide 31 for the control piston 27 are formed in a valve piece 32. Furthermore, the seat 21 of the control valve 1 is formed in the valve piece.

Die Ansteuerung des Aktors 2 erfolgt über einen elektrischen Kontakt 33. Der elektrische Kontakt 33 ist hier durch die Platte 7 geführt, damit dieser ortsfest ist und nicht mit dem oberen Gehäuseteil 6 mitbewegt wird.The actuation of the actuator 2 via an electrical contact 33. The electrical contact 33 is guided here by the plate 7 so that it is stationary and is not moved with the upper housing part 6.

Um den Einspritzvorgang zu starten, wird der Aktor 2 bestromt. Hierdurch dehnt sich der Aktor 2 aus. Da die untere Halterung 4 mit der Platte 7 ortsfest im Injektorgehäuse 8 aufgenommen ist, wirkt der Aktor 2 auf die obere Halterung 3 und damit auf das obere Gehäuseteil 6. Dieses wird angehoben. Hierdurch hebt sich auch der obere Abschnitt 11 des Ventilgliedes 12, der mit dem oberen Gehäuseteil 6 verbunden ist an. Hierdurch hebt sich auch das Schließelement 20 aus seinem Sitz und gibt die Verbindung vom Ablaufkanal 22 in den Kraftstoffrücklauf 25 frei. Kraftstoff strömt aus dem Steuerraum 24 in den Kraftstoffrücklauf 25. Hierdurch sinkt der Druck im Steuerraum 24 ab. Die Druckkraft, die auf die obere Stirnfläche 26 des Steuerkolbens 27 wirkt, wird hierdurch kleiner. Der Steuerkolben ist nicht mehr kraftausgeglichen und bewegt sich in den Steuerraum 24 hineein. Hierdurch vergrößert sich das Volumen eines hier nicht dargestellten Steuerraumes, der von dem Ende des Steuerkolbens 24 begrenzt wird, das der oberen Stirnfläche 26 gegenüberliegt. Der zweite Steuerraum wird weiterhin von einem Einspritzventilglied begrenzt. Durch den abnehmenden Druck wirkt eine geringere Druckkraft auf das Einspritzventilglied, so dass dieses aus seinem Sitz gehoben wird. Der Einspritzvorgang beginnt.To start the injection process, the actuator 2 is energized. As a result, the actuator 2 expands. Since the lower holder 4 is received with the plate 7 stationary in the injector 8, the actuator 2 acts on the upper bracket 3 and thus on the upper housing part 6. This is raised. This also raises the upper portion 11 of the valve member 12 which is connected to the upper housing part 6 at. As a result, the closing element 20 also lifts out of its seat and releases the connection from the outlet channel 22 into the fuel return 25. Fuel flows from the control chamber 24 into the fuel return 25. As a result, the pressure in the control chamber 24 decreases. The Compressive force acting on the upper end surface 26 of the control piston 27, thereby becomes smaller. The control piston is no longer force-balanced and moves into the control chamber 24. This increases the volume of a control chamber, not shown here, which is bounded by the end of the control piston 24, which is opposite to the upper end surface 26. The second control chamber is further limited by an injection valve member. Due to the decreasing pressure, a lower pressure force acts on the injection valve member, so that this is lifted from its seat. The injection process begins.

Um den Einspritzvorgang wieder zu beenden wird die Bestromung des Aktors 2 aufgehoben. Der Aktor 2 zieht sich zusammen. Hierdurch wird das obere Gehäuseteil 6, welches mit der oberen Halterung 3 verbunden ist, wieder nach unten bewegt. Hierdurch bewegt sich auch der obere Abschnitt 11 des Ventilgliedes 12 in Richtung des Sitzes 21. Der mit dem oberen Abschnitt 11 verbundene untere Abschnitt 17 des Ventilgliedes 12 bewegt sich ebenfalls in Richtung des Sitzes 21. Das Schließelement 20 wird in seinen Sitz 21 gestellt. Die Verbindung des Ablaufkanales 22 mit dem Kraftstoffrücklauf 25 wird verschlossen. Über die Zulaufdrossel 28 strömt unter Systemdruck stehender Kraftstoff in den Steuerraum 24. Im Steuerraum 24 baut sich somit wieder Systemdruck auf. Hierdurch nimmt die Druckkraft, die auf die obere Stirnfläche 26 des Steuerkolbens 27 wirkt, zu. Der Steuerkolben 27 wird in Richtung des zweiten Steuerraumes verschoben. Hierdurch nimmt das Volumen im zweiten Steuerraum ab, wodurch der Druck in diesem steigt. Aufgrund des steigenden Druckes nimmt die Druckkraft auf das Einspritzventilglied zu. Dieses wird in seinen Sitz gestellt. Hierdurch wird die Verbindung vom Düsenraum zur Einspritzöffnung verschlossen. Es kann kein Kraftstoff mehr aus dem Düsenraum über die Einspritzöffnung in den Brennraum strömen.To end the injection process again, the energization of the actuator 2 is released. The actuator 2 contracts. As a result, the upper housing part 6, which is connected to the upper bracket 3, moved back down. In this way, the upper portion 11 of the valve member 12 moves in the direction of the seat 21. The connected to the upper portion 11 lower portion 17 of the valve member 12 also moves in the direction of the seat 21. The closing element 20 is placed in its seat 21. The connection of the drainage channel 22 with the fuel return 25 is closed. Via the inlet throttle 28, fuel under system pressure flows into the control chamber 24. In the control chamber 24 system pressure therefore builds up again. As a result, the pressure force acting on the upper end surface 26 of the control piston 27 increases. The control piston 27 is moved in the direction of the second control chamber. As a result, the volume decreases in the second control chamber, whereby the pressure in this increases. Due to the increasing pressure, the pressure force on the injection valve member increases. This is put in his seat. As a result, the connection is closed from the nozzle chamber to the injection opening. It can no longer flow fuel from the nozzle chamber via the injection port into the combustion chamber.

Figur 2 zeigt einen Ausschnitt aus einem erfindungsgemäß ausgebildeten Kraftstoffinjektor in einer zweiten Ausführungsform. FIG. 2 shows a section of a inventively designed fuel injector in a second embodiment.

Bei der in Figur 2 dargestellten Ausführungsform ist die obere Halterung 3 des Aktors 2 nicht mit dem oberen Gehäuseteil 6 verbunden. Damit das obere Gehäuseteil 6 durch den Aktor 2 und die obere Halterung 3 angehoben werden kann, ist an der oberen Halterung 3 eine Schulter 40 ausgebildet. Die Schulter 40 wirkt mit einer zweiten Schulter 41 am oberen Gehäuseteil 6 zusammen. Sobald der Aktor 2 bestromt wird und sich ausdehnt, hebt sich das obere Gehäuseteil 3 in Richtung des oberen Gehäuseteils 6. Sobald die Schulter 40 der oberen Halterung 3 mit der zweiten Schulter 41 des oberen Gehäuseteiles 6 in Kontakt steht, wird das obere Gehäuseteil 6 angehoben. Bei nicht bestromtem Aktor 2 ist zwischen der Schulter 40 der oberen Halterung 3 und der zweiten Schulter 41 des oberen Gehäuseteiles 6 ein Spalt 42 ausgebildet. Der Spalt 42 dient als Vorhub, mit dem ein gegebenenfalls auftretender Hubfehler ausgeglichen werden kann. Dies ist zum Beispiel dann der Fall, wenn sich der Piezoaktor, wenn er nicht bestromt ist, weiter zusammenzieht falls sich das obere Gehäuseteil in Richtung des Steuerventils 1 bewegenen lässt.At the in FIG. 2 illustrated embodiment, the upper bracket 3 of the actuator 2 is not connected to the upper housing part 6. Thus, the upper housing part 6 can be raised by the actuator 2 and the upper bracket 3, a shoulder 40 is formed on the upper bracket 3. The shoulder 40 cooperates with a second shoulder 41 on the upper housing part 6. As soon as the actuator 2 is energized and expands, the upper housing part 3 rises in the direction of the upper housing part 6. Once the Shoulder 40 of the upper bracket 3 is in contact with the second shoulder 41 of the upper housing part 6, the upper housing part 6 is raised. When not energized actuator 2, a gap 42 is formed between the shoulder 40 of the upper bracket 3 and the second shoulder 41 of the upper housing part 6. The gap 42 serves as a forward stroke, with which an optionally occurring lifting error can be compensated. This is the case, for example, if the piezoelectric actuator, if it is not energized, contracts further if the upper housing part can be moved in the direction of the control valve 1.

Auch in der in Figur 2 dargestellten Ausführungsform ist das obere Gehäuseteil 6 von einer Abdeckung 13 umschlossen. Die Abdeckung 13 ist ortsfest mit dem Injektorgehäuse 8 verbunden. Um nach Beendigung des Einspritzvorganges, wenn die Bestromung aufgehoben wird und der Aktor 2 sich zusammenzieht das obere Gehäuseteil 6 wieder nach unten zu bewegen, damit das Steuerventil 1 geschlossen wird, umschließt in der hier dargestellten Ausführungsform ein Federelement 43 das obere Gehäuseteil 6. Das Federelement 43 ist in der hier dargestellten Ausführungsform eine als Spiralfeder ausgebildete Druckfeder. Damit das obere Gehäuseteil 6 bei nicht bestromtem Aktor 2 in Richtung des Steuerventils 1 bewegt wird, stützt sich das Federelement 43 mit einer Seite gegen die Abdeckung 13 und mit der anderen Seite gegen eine Erweiterung 44 am oberen Gehäuseteil ab. Sobald zum Beginn des Einspritzvorganges der Aktor 2 bestromt wird und sich ausdehnt und sich dadurch das obere Gehäuseteil 6 anhebt, wird das Federelement 43 gespannt. Wenn die Bestromung des Aktors 2 aufgehoben wird, um den Einspritzvorgang zu beenden, wirkt die Federkraft des Federelementes 43 auf die Erweiterung 44 des beweglichen oberen Gehäuseteils 6 und drückt dieses nach unten. Hierdurch wird das Steuerventil 1 geschlossen, indem das Schließelement 20 in seinen Sitz 21 gestellt wird. Um eine fehlerfreie Funktion des Kraftstoffinjektors zu erzielen, ist es unbedingt notwendig, dass die Abdeckung 13 in der in Figur 2 dargestellten Ausführungsform ortsfest mit dem Injektorgehäuse verbunden ist, damit diese sich nicht bewegen kann. Um eine ausreichend große Federkraft bereitzustellen, die auf die Erweiterung 44 am oberen Gehäuseteil 6 wirkt, ist das Federelement 43 auch bei nicht bestromtem und damit nicht ausgedehntem Aktor 2 bereits vorgespannt. Die gewählte Vorspannung ist dabei abhängig von der Kraft, die auf die Erweiterung 44 am oberen Gehäuseteil 6 wirken soll.Also in the in FIG. 2 illustrated embodiment, the upper housing part 6 is enclosed by a cover 13. The cover 13 is fixedly connected to the injector 8. In order, after completion of the injection process, when the energization is canceled and the actuator 2 contracts the upper housing part 6 to move down again so that the control valve 1 is closed, encloses in the embodiment shown here, a spring element 43, the upper housing part 6. The spring element 43 is in the embodiment shown here designed as a helical spring compression spring. So that the upper housing part 6 is moved in not energized actuator 2 in the direction of the control valve 1, the spring element 43 is supported with one side against the cover 13 and with the other side against an extension 44 on the upper housing part. As soon as the actuator 2 is energized at the beginning of the injection process and expands and thereby raises the upper housing part 6, the spring element 43 is tensioned. When the energization of the actuator 2 is released to end the injection process, the spring force of the spring element 43 acts on the extension 44 of the movable upper housing part 6 and pushes it down. As a result, the control valve 1 is closed by the closing element 20 is placed in its seat 21. In order to achieve a faultless function of the fuel injector, it is essential that the cover 13 in the in FIG. 2 illustrated embodiment is fixedly connected to the injector, so that they can not move. In order to provide a sufficiently large spring force acting on the extension 44 on the upper housing part 6, the spring element 43 is already biased even when not energized and thus not extended actuator 2. The selected bias voltage is dependent on the force that is to act on the extension 44 on the upper housing part 6.

Claims (10)

  1. Apparatus for injecting fuel into a combustion chamber of an internal combustion engine, in which a control valve (1) for actuating an injection-valve member is operated by way of an actuator (2) which extends when current is supplied, the control valve (1) being open when current is applied to the actuator (2) and being closed when current is not applied to the actuator (2), and the actuator (2) being enclosed by an upper housing part (6), and the upper housing part (6) being axially displaceable with respect to an injector housing (8) and being connected to a valve member (12) of the control valve (1), characterized in that the upper housing part (6) is mounted on the valve member (12) by way of bolts (10), the bolts (10) being guided through apertures (9) in a plate (7) which is connected fixedly to the injector housing (8) and on which the actuator (2) is supported.
  2. Apparatus according to Claim 1, characterized in that the actuator (2) is a piezoelectric actuator.
  3. Apparatus according to Claim 1 or 2, characterized in that the upper housing part (6) is enclosed by a cover (13) which is connected to the injector housing (8).
  4. Apparatus according to one of Claims 1 to 3, characterized in that a diaphragm (16) is received between the actuator (2) and a closing element (20) which is connected to the valve member (12), by way of which diaphragm (16) the actuator (2) is sealed against fuel.
  5. Apparatus according to one of Claims 1 to 4, characterized in that the actuator (2) is fastened positively to an upper holder (3) on the upper housing part (6).
  6. Apparatus according to one of Claims 1 to 6, characterized in that the upper holder (3) of the actuator (2) is not connected to the upper housing part (6) and a gap (42) is formed between the upper holder (3) and the upper housing part (6).
  7. Apparatus according to Claim 6, characterized in that a spring element (43) is received between the upper housing part (6) and the cover (13), which spring element (43) is supported on one side on the upper housing part (6) and on the other side on the cover (13).
  8. Apparatus according to Claim 7, characterized in that the spring element (43) encloses the upper housing part (6) and is supported on one side on a widened portion (44) on the upper housing part (6) and on the other side on the cover (13).
  9. Apparatus according to one of Claims 1 to 8, characterized in that the valve member (12) comprises an adjustment disc (18), by way of which the stroke is set.
  10. Apparatus according to one of Claims 1 to 4, characterized in that the upper housing part (6) is manufactured from Invar.
EP07106972A 2006-06-07 2007-04-26 Device for injecting fuel Not-in-force EP1865195B1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE102006026397A DE102006026397A1 (en) 2006-06-07 2006-06-07 Device for injecting fuel

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EP1865195A1 EP1865195A1 (en) 2007-12-12
EP1865195B1 true EP1865195B1 (en) 2009-08-19

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP07106972A Not-in-force EP1865195B1 (en) 2006-06-07 2007-04-26 Device for injecting fuel

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EP (1) EP1865195B1 (en)
AT (1) ATE440217T1 (en)
DE (2) DE102006026397A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102017208269A1 (en) * 2017-05-17 2018-11-22 Robert Bosch Gmbh Conveying unit for a fuel cell assembly for conveying and controlling a gaseous medium

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19519191C2 (en) * 1995-05-24 1997-04-10 Siemens Ag Injector
DE19702066C2 (en) * 1997-01-22 1998-10-29 Daimler Benz Ag Piezoelectric injector for fuel injection systems of internal combustion engines
IT1320475B1 (en) * 2000-06-30 2003-11-26 Fiat Ricerche SELF-COMPENSATED PIEZOELECTRIC ACTUATOR FOR A CONTROL VALVE.
JP4161635B2 (en) * 2002-08-19 2008-10-08 株式会社デンソー Fuel injection control device
DE20220800U1 (en) * 2002-10-24 2004-04-08 Vermes Technik Gmbh & Co. Kg Positioning system with piezoactuator has links between piezoactuator and transmission lever provided as rolling butt contact forming line contact and transmission lever is preloaded by spring
DE102004057464A1 (en) * 2004-11-29 2006-06-01 Robert Bosch Gmbh Piezoelectric actuator for internal combustion engine, has push rods guided in actuator movement direction through housing parts that are connected with one another after joining component parts of actuator

Also Published As

Publication number Publication date
DE102006026397A1 (en) 2007-12-13
EP1865195A1 (en) 2007-12-12
ATE440217T1 (en) 2009-09-15
DE502007001327D1 (en) 2009-10-01

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