EP2726728B1 - Fuel injector - Google Patents

Fuel injector Download PDF

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Publication number
EP2726728B1
EP2726728B1 EP12720199.4A EP12720199A EP2726728B1 EP 2726728 B1 EP2726728 B1 EP 2726728B1 EP 12720199 A EP12720199 A EP 12720199A EP 2726728 B1 EP2726728 B1 EP 2726728B1
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EP
European Patent Office
Prior art keywords
fuel injector
return
chamber
fuel
control valve
Prior art date
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Application number
EP12720199.4A
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German (de)
French (fr)
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EP2726728A1 (en
Inventor
Florian Schmid
Johannes UNRATH
Eike Kobes
Holger Rapp
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Robert Bosch GmbH
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Robert Bosch GmbH
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Publication of EP2726728A1 publication Critical patent/EP2726728A1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • 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
    • F02M55/00—Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump F02M37/00
    • F02M55/002—Arrangement of leakage or drain conduits in or from injectors
    • 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
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/0031—Valves characterized by the type of valves, e.g. special valve member details, valve seat details, valve housing details
    • F02M63/0043—Two-way valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/007—Details not provided for in, or of interest apart from, the apparatus of the groups F02M63/0014 - F02M63/0059
    • F02M63/0073—Pressure balanced valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M2547/00—Special features for fuel-injection valves actuated by fluid pressure
    • F02M2547/001—Control chambers formed by movable sleeves

Definitions

  • the invention relates to a fuel injector according to the preamble of claim 1, such as in the EP 2275666 shown.
  • Such a fuel injector is from the DE 10 2008 001 330 A1 the applicant known.
  • the movement of a nozzle needle arranged in a nozzle needle is generated via a control valve, which has a valve element, which in turn via a solenoid actuator or a piezoelectric actuator, at least indirectly, is controlled.
  • a control amount is derived in the receiving space of the Magnetaktors or the piezoelectric actuator, which in turn has a connection to a return port to the fuel injector.
  • the outflow of the fuel via throttles and the valve seat of the valve element is associated with a strong pressure reduction of the originally high-pressure fuel. Such pressure reduction is physically associated with a temperature increase of the fuel.
  • the present invention seeks to further develop a fuel injector according to the preamble of claim 1 such that the flowing into the receiving space for the piezoelectric actuator as well as in the return bore fuel occurs with respect to the prior art reduced temperature, without the need for additional (external) fuel supply from an area outside the fuel injector.
  • This object is achieved in a fuel injector with the features of claim 1 according to the invention that the outflowing when switching the control valve control amount passes through a flow path in an annular intermediate region between the nozzle retaining nut and the nozzle body and / or the valve plate and / or throttle plate. There, the fuel can be cooled before it enters the immediate vicinity of temperature-sensitive components.
  • connection to or from the annular intermediate region comprises, wherein the return channel opens at least indirectly in the return bore.
  • the diversion channel and the return channel are formed at least substantially as arranged radially to the longitudinal axis of the valve plate channels.
  • the discharge channel and the return channel on opposite sides of the from the valve plate, the throttle plate and the Nozzle body existing composite are arranged.
  • control quantity flows out of the control valve chamber into the actuator chamber.
  • connection has a drain, which opens into a discharge channel.
  • discharge channel opens through the annulus and a return passage in a riser, which is connected to the return line.
  • a fuel injector 1 according to the prior art is shown in longitudinal section.
  • the fuel injector 1 has a holding body 2, a valve plate 4, a throttle plate 6 and a nozzle body 8 which abut each other in this order.
  • the components are pressed against each other by a (nozzle) clamping nut 9, which is supported on a shoulder of the nozzle body 8 and is held by a thread on the holding body 2.
  • a (nozzle) clamping nut 9 which is supported on a shoulder of the nozzle body 8 and is held by a thread on the holding body 2.
  • an annular space 5 is formed, in the area at least the valve plate 4 and the throttle plate 6 spaced from the clamping nut 9 are arranged.
  • a pressure chamber 14 is formed, in which a piston-shaped nozzle needle 10 is arranged longitudinally displaceable.
  • the nozzle needle 10 has at its end facing the combustion chamber on a sealing surface 11, with which it cooperates with a nozzle seat 13 which is formed at the combustion chamber end of the pressure chamber 14. From the nozzle seat 13 go from one or more injection ports 12, which open in installation position of the fuel injector 1 directly into a combustion chamber of the internal combustion engine.
  • the nozzle needle 10 is guided in a middle section in the pressure chamber 14, wherein the fuel is passed through a plurality of bevels 15 to the injection openings 12.
  • the nozzle needle 10 is guided at its end remote from the combustion chamber of the internal combustion engine in a sleeve 22, wherein the sleeve 22 by a closing spring 18 which surrounds the nozzle needle 10 and the sleeve 22 facing away indirectly supported on a shoulder 16, presses against the throttle plate 6 ,
  • a control chamber 20 is limited, which is filled with fuel, so that exerted by the pressure in the control chamber 20, a hydraulic force on the side remote from the combustion chamber end face of the nozzle needle 10 and exerts a force in the direction of the nozzle seat 13 on the nozzle needle 10.
  • an inlet channel 25 is formed, is passed through the compressed fuel under high pressure from a high-pressure fuel source in the pressure chamber 14.
  • the inlet channel 25 is connected to the control chamber 20 via an inlet throttle 40 extending in the throttle plate 6.
  • control valve 30 For controlling the fuel pressure in the control chamber 20, the switchable between two switching positions control valve 30 is provided in the valve plate 4, wherein the control valve 30 has a control valve chamber 31 which is formed as a cavity in the valve plate 4.
  • the control valve chamber 31 is via an outlet throttle 42, which is formed in the throttle plate 6, connected to the control chamber 20 in the nozzle body 8.
  • a control valve member 34 is arranged longitudinally displaceable, wherein the control valve member 34 has a piston-shaped shape and at its end facing away from the throttle plate 6 has a mushroom-shaped extension on which a sealing surface 52 is formed, with which the control valve member 34 cooperates with a control valve seat 37, which is formed on the inside of the control valve chamber 31.
  • the control valve member 34 is guided at its end remote from the control valve seat 37 in a sleeve 36 which is supported at one end to the throttle plate 6, and between which and the control valve member 34, a spring 38 is arranged under compressive prestress.
  • a spring 38 is arranged under compressive prestress.
  • the control valve member 34 is pressed against the control valve seat 37, and on the other hand, the sleeve 36 against the throttle plate 6.
  • the piston 32 with the coupler housing 33 is in this case formed in a Aktorfactraum formed, always at low pressure actuator chamber 23, which is always depressurized.
  • a leakage chamber 54 is limited, in which a low pressure is present, and is relieved of pressure via a drain 45 drain.
  • the leakage oil drain 45 may in this case have, for example, a connection to the actuator chamber 23.
  • the fuel injector 100 In order to keep the component load on the piezoelectric actuator in the actuator chamber 23 as low as possible it is at a in the Fig. 2 fuel injector 100 according to the invention provided that the fuel flowing through the control valve seat 37 in the direction of the coupler body 33 at least partially, but preferably completely guided or discharged via one or more diversion channels 60 in the annular space 5.
  • a single diversion channel 60 is shown, which is arranged radially to the longitudinal axis of the valve plate 4.
  • the diversion channel 60 is located in an upper end region of the valve plate 4 with respect to the fuel injector 100.
  • the flow guide according to the Fig. 2 a drainage 45a, which has a connection in the throttle plate 6 radially arranged discharge 71 with the annular space 5.
  • a radially arranged herbleitkanal 72 is formed in an upper axial region, which also has connection with the annular space 5, and which opens into the riser 64.
  • a surface exposure region 73 is still formed, which forms a hydraulic connection between the actuator chamber 23 and the return bore 65.
  • Fig. 4 is one opposite the Fig. 3 modified flow guidance for the fuel from the leakage chamber 54 shown.
  • the fuel also passes through the leakage oil drain 45a and the discharge channel 71 into the annulus 5.
  • the return channel 75 consisting of the partial channel sections 76, 77 formed in the throttle plate 6, the same Has connection with the annular space 5, and which opens into the riser 64. It may be provided that the vertical part of the channel section 76 of the return channel 75 is not concentric with the riser 64, but is arranged in a certain offset to this.
  • a separating web (not shown) may be present in the preferably shorter distance between the vertical partial channel section 76 and the riser 64, so that the fuel has as long a flow path as possible until it enters the riser 64.
  • the fuel injector 100 according to the invention thus far described can be modified or modified in many ways without departing from the spirit of the invention. Conceivable modifications of the fuel injector 100 may be e.g. be such that only the fuel in the leakage chamber 54 is passed through the annulus 5. Finally, it is also conceivable to form the discharge of the fuel from the annular space 5 via a formed in the holding body 2 radial bore or formed in an end face of the holding body 2, radially extending groove directly into the return bore 65.

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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)
  • Fuel-Injection Apparatus (AREA)

Description

Stand der TechnikState of the art

Die Erfindung betrifft einen Kraftstoffinjektor nach dem Oberbegriff des Anspruchs 1, wie z.B. in der EP 2275666 gezeigt.The invention relates to a fuel injector according to the preamble of claim 1, such as in the EP 2275666 shown.

Ein derartiger Kraftstoffinjektor ist aus der DE 10 2008 001 330 A1 der Anmelderin bekannt. Bei dem bekannten Kraftstoffinjektor wird die Bewegung einer in einem Düsenkörper angeordneten Düsennadel über ein Steuerventil erzeugt, das ein Ventilelement aufweist, das wiederum über einen Magnetaktor oder einen Piezoaktor, zumindest mittelbar, angesteuert wird. Bei einer Bewegung des Ventilelements, die erforderlich ist, um ein Abheben der Düsennadel von ihrem Dichtsitz zu ermöglichen, wird eine Steuermenge in den Aufnahmeraum des Magnetaktors bzw. des Piezoaktors abgeleitet, welcher wiederum Verbindung zu einem Rücklaufanschluss am Kraftstoffinjektor hat. Das Abströmen des Kraftstoffes über Drosseln und den Ventilsitz des Ventilelements ist mit einer starken Druckverminderung des ursprünglich unter Hochdruck befindlichen Kraftstoffs verbunden. Eine derartige Druckverminderung ist physikalisch mit einer Temperaturerhöhung des Kraftstoffs verbunden.Such a fuel injector is from the DE 10 2008 001 330 A1 the applicant known. In the known fuel injector, the movement of a nozzle needle arranged in a nozzle needle is generated via a control valve, which has a valve element, which in turn via a solenoid actuator or a piezoelectric actuator, at least indirectly, is controlled. In a movement of the valve element, which is required to allow lifting of the nozzle needle from its sealing seat, a control amount is derived in the receiving space of the Magnetaktors or the piezoelectric actuator, which in turn has a connection to a return port to the fuel injector. The outflow of the fuel via throttles and the valve seat of the valve element is associated with a strong pressure reduction of the originally high-pressure fuel. Such pressure reduction is physically associated with a temperature increase of the fuel.

Derzeitige Kraftstoffeinspritzsysteme bei selbstzündenden Brennkraftmaschinen arbeiten mit einem Systemdruck von etwa 1500bar bis maximal etwa 2000bar. Für zukünftige Entwicklungen ist es aus Gründen der Kraftstoffeffizienz geplant, den Systemdruck auf deutlich mehr als 2000bar zu erhöhen. Das bedeutet, dass bei dem angesprochenen Abströmen der Steuermenge im Bereich des Steuerventils eine noch stärkere Druckreduzierung mit einer damit verbundenen noch stärkeren Erhöhung der Kraftstofftemperatur verbunden ist. Insbesondere bei Piezoaktoren gibt es eine Temperaturobergrenze, bis zu der die Piezoaktoren zuverlässig arbeiten, ohne dass hierzu zusätzliche konstruktive Maßnahmen bzw. Piezoaktoren aus temperaturbeständigeren Materialien erforderlich sind. Bei der angesprochenen geplanten Systemdruckerhöhung gelangt man jedoch in einen Temperaturbereich des Kraftstoffs, bei dem bei herkömmlichen Piezoaktoren ein zuverlässiger Betrieb nicht mehr gewährleistet ist. Aus diesem Grund ist es beispielsweise aus der nachveröffentlichten DE 10 2010 040381 A1 der Anmelderin bekannt, den Raum, in dem sich der Piezoaktor befindet, mittels eines zusätzlichen Kraftstoffzuflusses mit kühlerem bzw. vorab nicht durch den Hochdruckkreislauf geflossenem Kraftstoff zu kühlen. Eine derartige Maßnahme ist jedoch konstruktiv relativ aufwändig und erzeugt folglich unerwünschte Zusatzkosten.Current fuel injection systems in auto-ignition internal combustion engines operate at a system pressure of about 1500 bar to a maximum of about 2000 bar. For future fuel efficiency reasons, it is planned to increase the system pressure to well over 2000bar. This means that in the mentioned outflow of the control amount in the region of the control valve, an even greater pressure reduction is associated with an associated even greater increase in the fuel temperature. Especially with piezo actuators there is a temperature upper limit up to which the piezo actuators work reliably, without the need for additional design measures or piezoelectric actuators made of more temperature-resistant materials are required. However, in the case of the aforementioned planned system pressure increase, a temperature range of the fuel is reached at which reliable operation is no longer guaranteed in the case of conventional piezoelectric actuators. For this reason, it is for example from the post-published DE 10 2010 040381 A1 the applicant known to cool the space in which the piezoelectric actuator is located by means of an additional fuel flow with cooler or not previously flowed through the high-pressure circuit fuel. However, such a measure is structurally relatively complex and thus generates undesirable additional costs.

Offenbarung der ErfindungDisclosure of the invention

Ausgehend von dem dargestellten Stand der Technik liegt der Erfindung die Aufgabe zugrunde, einen Kraftstoffinjektor nach dem Oberbegriff des Anspruchs 1 derart weiterzubilden, dass der in den Aufnahmeraum für den Piezoaktor als auch in die Rücklaufbohrung einströmende Kraftstoff mit gegenüber dem Stand der Technik reduzierter Temperatur eintritt, ohne dass hierzu zusätzliche (externe) Kraftstoffzuführungen aus einem Bereich außerhalb des Kraftstoffinjektors erforderlich sind. Diese Aufgabe wird bei einem Kraftstoffinjektor mit den Merkmalen des Anspruchs 1 erfindungsgemäß dadurch gelöst, dass die beim Schalten des Steuerventils abströmende Steuermenge über einen Strömungsweg in einen ringförmigen Zwischenbereich zwischen der Düsenspannmutter und dem Düsenkörper und/oder der Ventilplatte und/oder der Drosselplatte gelangt. Dort kann der Kraftstoff abgekühlt werden, bevor er in die unmittelbare Umgebung temperaturempfindlicher Bauteile gelangt.Based on the illustrated prior art, the present invention seeks to further develop a fuel injector according to the preamble of claim 1 such that the flowing into the receiving space for the piezoelectric actuator as well as in the return bore fuel occurs with respect to the prior art reduced temperature, without the need for additional (external) fuel supply from an area outside the fuel injector. This object is achieved in a fuel injector with the features of claim 1 according to the invention that the outflowing when switching the control valve control amount passes through a flow path in an annular intermediate region between the nozzle retaining nut and the nozzle body and / or the valve plate and / or throttle plate. There, the fuel can be cooled before it enters the immediate vicinity of temperature-sensitive components.

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

In einer konstruktiven bevorzugten Umsetzung der Verbindung zum bzw. vom ringförmigen Zwischenbereich wird vorgeschlagen, dass die weitere Verbindung einen Ausleitkanal in den Ringraum und einen Rückleitkanal aus dem Ringraum umfasst, wobei der Rückleitkanal zumindest mittelbar in der Rücklaufbohrung mündet.In a constructive preferred implementation of the connection to or from the annular intermediate region is proposed that the further connection a discharge channel into the annulus and a return channel from the annulus comprises, wherein the return channel opens at least indirectly in the return bore.

Ganz besonders bevorzugt ist es vorgesehen, dass der Ausleitkanal und der Rückleitkanal zumindest im Wesentlichen als radial zur Längsachse der Ventilplatte angeordnete Kanäle ausgebildet sind.Most preferably, it is provided that the diversion channel and the return channel are formed at least substantially as arranged radially to the longitudinal axis of the valve plate channels.

Um einen möglichst langen Strömungsweg bzw. eine möglichst lange Verweilzeit des heißen Kraftstoffs in dem ringförmigen Zwischenbereich zu ermöglichen, ist es in einer weiteren Variante der Erfindung vorgesehen, dass der Ausleitkanal und der Rücklaufkanal auf einander gegenüberliegenden Seiten des aus der Ventilplatte, der Drosselplatte und des Düsenkörpers bestehenden Verbunds angeordnet sind.In order to allow the longest possible flow path or the longest possible residence time of the hot fuel in the annular intermediate region, it is provided in a further variant of the invention that the discharge channel and the return channel on opposite sides of the from the valve plate, the throttle plate and the Nozzle body existing composite are arranged.

Zusätzlich kann es weiterhin vorgesehen sein, dass ein Teil der Steuermenge aus dem Steuerventilraum in den Aktorraum abströmt. Mit anderen Worten gesagt bedeutet dies, dass lediglich ein Teil der Steuermenge über den ringförmigen Zwischenbereich geführt wird, während ein anderer Teil der Steuermenge unmittelbar in den Aktorraum abgeleitet wird.In addition, it may further be provided that a part of the control quantity flows out of the control valve chamber into the actuator chamber. In other words, this means that only part of the control amount is passed over the annular intermediate area, while another part of the control amount is discharged directly into the actuator space.

Aus der eingangs erwähnten DE 10 2008 001 330 A1 ist es bekannt, das Steuerventil mit einer Dichthülse auszubilden, in der der Steuerbolzen längsverschiebbar angeordnet ist. Über den Ringspalt zwischen dem Ventilbolzen und der Dichthülse gelangt unter Hochdruck stehender Kraftstoff in einen Leckage-bzw. Niederdruckraum bzw. eine Ablaufbohrung. Da der in den Ringspalt einströmende Kraftstoff bereits zuvor ggf. durch das Durchströmen der Drosseln erwärmt und anschließend durch das Schließen des Steuerventils erneut komprimiert wurde, kann hier durch eine nochmalige Erwärmung des bereits erhitzten Kraftstoffs eine besonders hohe Kraftstofftemperatur entstehen. Daher wird in einer weiteren Variante vorgeschlagen, dass eine zusätzliche Verbindung zwischen dem Leckage- bzw. Niederdruckraum und der Rücklaufbohrung vorgesehen ist, die mit dem Ringraum verbunden ist.From the above-mentioned DE 10 2008 001 330 A1 It is known to form the control valve with a sealing sleeve, in which the control bolt is arranged longitudinally displaceable. About the annular gap between the valve pin and the sealing sleeve passes under high pressure fuel in a leakage or. Low pressure chamber or a drain hole. Since the fuel flowing into the annular gap has previously been heated, if necessary, by the flow through the throttles and then compressed again by the closing of the control valve, a particularly high fuel temperature can be produced here by reheating the already heated fuel. Therefore, it is proposed in a further variant that an additional connection between the leakage or low-pressure chamber and the return bore is provided, which is connected to the annulus.

In einer Variante der letztgenannten Ausführung ist es möglich, dass die Verbindung einen Ablauf aufweist, der in einen Ausleitkanal mündet. Zusätzlich kann es vorgesehen sein, dass der Ausleitkanal über den Ringraum und einen Rückleitkanal in eine Steigleitung mündet, die mit der Rücklaufleitung verbunden ist. Eine soweit beschriebene Ausgestaltung lässt sich konstruktiv relativ einfach und kompakt ausbilden.In a variant of the last-mentioned embodiment, it is possible that the connection has a drain, which opens into a discharge channel. Additionally it can be provided be that the discharge channel opens through the annulus and a return passage in a riser, which is connected to the return line. An embodiment described so far can be structurally relatively simple and compact form.

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

Diese zeigt in:

Fig. 1
einen Teilbereich eines Kraftstoffinjektors gemäß dem Stand der Technik in einem Längsschnitt,
Fig. 2
einen Ausschnitt aus einem erfindungsgemäßen Kraftstoffinjektor, bei der eine Steuermenge an Kraftstoff aus einem Steuerraum erfindungsgemäß über einen Ringraum geführt, als auch erneut in den Verbund der im konkreten Fall zwischen einem Haltekörper und einer Düsenspannmutter verspannten Platten eingeleitet wird, wobei die Steuermenge über einen Rücklaufpfad aus dem Injektor ausgeleitet werden kann, in einem geknickten Längsschnitt und
Fig. 3 und Fig. 4
einen erfindungsgemäßen Kraftstoffinjektor, bei dem eine Leckagemenge aus einem Niederdruckraum in einem Ringraum gekühlt wird, ebenfalls in geknickten Längsschnitten.
This shows in:
Fig. 1
a portion of a fuel injector according to the prior art in a longitudinal section,
Fig. 2
a section of a fuel injector according to the invention, in which a control amount of fuel from a control room according to the invention led through an annulus, as is again introduced into the composite of braced in the specific case between a holding body and a nozzle retaining nut plates, wherein the control amount via a return path the injector can be discharged in a kinked longitudinal section and
FIG. 3 and FIG. 4
a fuel injector according to the invention, in which a leakage amount from a low-pressure space is cooled in an annular space, also in kinked longitudinal sections.

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

In der Fig. 1 ist ein Kraftstoffinjektor 1 nach dem Stand der Technik im Längsschnitt dargestellt. Der Kraftstoffinjektor 1 weist einen Haltekörper 2, eine Ventilplatte 4, eine Drosselplatte 6 und einen Düsenkörper 8 auf, die in dieser Reihenfolge aneinander anliegen. Die Bauteile werden durch eine (Düsen-) Spannmutter 9 gegeneinander gepresst, die sich an einer Schulter des Düsenkörpers 8 abstützt und durch ein Gewinde am Haltekörper 2 gehalten wird. Zwischen der Spannmutter 9 und einem Teilbereich des Düsenkörpers 8 sowie über die gesamte Höhe der Ventilplatte 4 und der Drosselplatte 6 ist ein Ringraum 5 ausgebildet, in dessen Bereich zumindest die Ventilplatte 4 und die Drosselplatte 6 beabstandet zur Spannmutter 9 angeordnet sind. Im Düsenkörper 8 ist ein Druckraum 14 ausgebildet, in dem eine kolbenförmige Düsennadel 10 längsverschiebbar angeordnet ist. Die Düsennadel 10 weist an ihrem dem Brennraum zugewandten Ende eine Dichtfläche 11 auf, mit der sie mit einem Düsensitz 13 zusammenwirkt, der am brennraumseitigen Ende des Druckraums 14 ausgebildet ist. Vom Düsensitz 13 gehen eine oder mehrere Einspritzöffnungen 12 ab, die in Einbaulage des Kraftstoffinjektors 1 direkt in einen Brennraum der Brennkraftmaschine münden. Die Düsennadel 10 wird in einem mittleren Abschnitt im Druckraum 14 geführt, wobei der Kraftstoff durch mehrere Anschliffe 15 zu den Einspritzöffnungen 12 geleitet wird.In the Fig. 1 a fuel injector 1 according to the prior art is shown in longitudinal section. The fuel injector 1 has a holding body 2, a valve plate 4, a throttle plate 6 and a nozzle body 8 which abut each other in this order. The components are pressed against each other by a (nozzle) clamping nut 9, which is supported on a shoulder of the nozzle body 8 and is held by a thread on the holding body 2. Between the Clamping nut 9 and a portion of the nozzle body 8 and over the entire height of the valve plate 4 and the throttle plate 6, an annular space 5 is formed, in the area at least the valve plate 4 and the throttle plate 6 spaced from the clamping nut 9 are arranged. In the nozzle body 8, a pressure chamber 14 is formed, in which a piston-shaped nozzle needle 10 is arranged longitudinally displaceable. The nozzle needle 10 has at its end facing the combustion chamber on a sealing surface 11, with which it cooperates with a nozzle seat 13 which is formed at the combustion chamber end of the pressure chamber 14. From the nozzle seat 13 go from one or more injection ports 12, which open in installation position of the fuel injector 1 directly into a combustion chamber of the internal combustion engine. The nozzle needle 10 is guided in a middle section in the pressure chamber 14, wherein the fuel is passed through a plurality of bevels 15 to the injection openings 12.

Die Düsennadel 10 ist an ihrem vom Brennraum der Brennkraftmaschine abgewandten Ende in einer Hülse 22 geführt, wobei die Hülse 22 durch eine Schließfeder 18, die die Düsennadel 10 umgibt und sich der Hülse 22 abgewandt mittelbar an einem Absatz 16 abstützt, gegen die Drosselplatte 6 drückt. Durch die Hülse 22, die vom Brennraum abgewandten Stirnseite der Düsennadel 10 und die Drosselplatte 6 wird ein Steuerraum 20 begrenzt, der mit Kraftstoff befüllt ist, so dass durch den Druck im Steuerraum 20 eine hydraulische Kraft auf die vom Brennraum abgewandte Stirnseite der Düsennadel 10 ausgeübt wird und eine Kraft in Richtung des Düsensitzes 13 auf die Düsennadel 10 ausübt.The nozzle needle 10 is guided at its end remote from the combustion chamber of the internal combustion engine in a sleeve 22, wherein the sleeve 22 by a closing spring 18 which surrounds the nozzle needle 10 and the sleeve 22 facing away indirectly supported on a shoulder 16, presses against the throttle plate 6 , Through the sleeve 22, facing away from the combustion chamber end face of the nozzle needle 10 and the throttle plate 6, a control chamber 20 is limited, which is filled with fuel, so that exerted by the pressure in the control chamber 20, a hydraulic force on the side remote from the combustion chamber end face of the nozzle needle 10 and exerts a force in the direction of the nozzle seat 13 on the nozzle needle 10.

Im Haltekörper 2, der Ventilplatte 4 und der Drosselplatte 6 ist ein Zulaufkanal 25 ausgebildet, über den verdichteter Kraftstoff unter hohem Druck von einer Kraftstoffhochdruckquelle in den Druckraum 14 geleitet wird. Der Zulaufkanal 25 ist mit dem Steuerraum 20 über eine in der Drosselplatte 6 verlaufende Zulaufdrossel 40 verbunden. Mit einer gewissen zeitlichen Verzögerung stellt sich so bei geschlossenem Steuerventil 30 stets der gleiche Kraftstoffdruck im Zulaufkanal 25 und im Steuerraum 20 ein.In the holding body 2, the valve plate 4 and the throttle plate 6, an inlet channel 25 is formed, is passed through the compressed fuel under high pressure from a high-pressure fuel source in the pressure chamber 14. The inlet channel 25 is connected to the control chamber 20 via an inlet throttle 40 extending in the throttle plate 6. With a certain time delay, the same fuel pressure always occurs in the inlet channel 25 and in the control chamber 20 when the control valve 30 is closed.

Zur Steuerung des Kraftstoffdrucks im Steuerraum 20 ist das zwischen zwei Schaltstellungen schaltbares Steuerventil 30 in der Ventilplatte 4 vorgesehen, wobei das Steuerventil 30 einen Steuerventilraum 31 aufweist, der als Hohlraum in der Ventilplatte 4 ausgebildet ist. Der Steuerventilraum 31 ist über eine Ablaufdrossel 42, die in der Drosselplatte 6 ausgebildet ist, mit dem Steuerraum 20 im Düsenkörper 8 verbunden. Im Steuerventilraum 31 ist ein Steuerventilglied 34 längsverschiebbar angeordnet, wobei das Steuerventilglied 34 eine kolbenförmige Gestalt aufweist und an seinem der Drosselplatte 6 abgewandten Ende eine pilzförmige Erweiterung hat, an der eine Dichtfläche 52 ausgebildet ist, mit der das Steuerventilglied 34 mit einem Steuerventilsitz 37 zusammenwirkt, der an der Innenseite des Steuerventilraums 31 ausgebildet ist.For controlling the fuel pressure in the control chamber 20, the switchable between two switching positions control valve 30 is provided in the valve plate 4, wherein the control valve 30 has a control valve chamber 31 which is formed as a cavity in the valve plate 4. The control valve chamber 31 is via an outlet throttle 42, which is formed in the throttle plate 6, connected to the control chamber 20 in the nozzle body 8. In the control valve chamber 31, a control valve member 34 is arranged longitudinally displaceable, wherein the control valve member 34 has a piston-shaped shape and at its end facing away from the throttle plate 6 has a mushroom-shaped extension on which a sealing surface 52 is formed, with which the control valve member 34 cooperates with a control valve seat 37, which is formed on the inside of the control valve chamber 31.

Das Steuerventilglied 34 ist an seinem dem Steuerventilsitz 37 abgewandten Ende in einer Hülse 36 geführt, die sich mit einem Ende an der Drosselplatte 6 abstützt, und zwischen der und dem Steuerventilglied 34 eine Feder 38 unter Druckvorspannung angeordnet ist. Durch die Kraft der Feder 38 wird einerseits das Steuerventilglied 34 gegen den Steuerventilsitz 37 gepresst, und andererseits die Hülse 36 gegen die Drosselplatte 6. Die Bewegung des Steuerventilglieds 34 im Steuerventilraum 31 geschieht über einen in einem Kopplergehäuse 33 geführten Kolben 32, der im Haltekörper 2 angeordnet ist, und der durch einen elektrischen Aktor in seiner Längsrichtung bewegbar ist, insbesondere durch einen einzelnen nicht dargestellten Piezoaktor. Der Kolben 32 mit dem Kopplergehäuse 33 befindet sich hierbei in einem als Aktoraufnahmeraum ausgebildeten, stets unter Niederdruck stehenden Aktorraum 23, der stets druckentlastet ist.The control valve member 34 is guided at its end remote from the control valve seat 37 in a sleeve 36 which is supported at one end to the throttle plate 6, and between which and the control valve member 34, a spring 38 is arranged under compressive prestress. By the force of the spring 38 on the one hand, the control valve member 34 is pressed against the control valve seat 37, and on the other hand, the sleeve 36 against the throttle plate 6. The movement of the control valve member 34 in the control valve chamber 31 via a guided in a coupler housing 33 piston 32 which in the holding body is arranged, and which is movable by an electric actuator in its longitudinal direction, in particular by a single piezoelectric actuator, not shown. The piston 32 with the coupler housing 33 is in this case formed in a Aktoraufnahmeraum formed, always at low pressure actuator chamber 23, which is always depressurized.

Durch die Hülse 36, das Steuerventilglied 34 und die Drosselplatte 6 wird ein Leckageraum 54 begrenzt, in dem ein Niederdruck vorhanden ist, und der über einen Leckölablauf 45 druckentlastet ist. Der Leckölablauf 45 kann hierbei beispielsweise eine Verbindung mit dem Aktorraum 23 aufweisen.Through the sleeve 36, the control valve member 34 and the throttle plate 6, a leakage chamber 54 is limited, in which a low pressure is present, and is relieved of pressure via a drain 45 drain. The leakage oil drain 45 may in this case have, for example, a connection to the actuator chamber 23.

Bezüglich der Funktionsweise eines derartigen, aus dem Stand der Technik bekannten Kraftstoffinjektors 1 wird auf die DE 10 2008 001 330 A1 der Anmelderin verwiesen, die insoweit Bestandteil dieser Anmeldung sein soll.Regarding the operation of such, known from the prior art fuel injector 1 is on the DE 10 2008 001 330 A1 the applicant referred, which should be part of this application.

Beim Betrieb des Kraftstoffinjektors 1 gelangt Kraftstoff beim Öffnen des Steuerventils 30 über den Steuerventilsitz 37 und durch Abströmbohrungen 35 im Kopplergehäuse 33 in den Aktorraum 23, in dem auch der Piezoaktor angeordnet ist. Infolge der Druckreduzierung des Kraftstoffes weist der Kraftstoff dabei eine relativ hohe Temperatur auf. Dabei erwärmt sich der Kraftstoff umso mehr, desto höher der Systemdruck bzw. der Betriebsdruck des Kraftstoffinjektors 1 ist, da in diesem Fall eine besonders große Druckreduzierung mit einer damit verbundenen besonders großen Temperaturerhöhung des Kraftstoffes einhergeht.During operation of the fuel injector 1, when the control valve 30 is opened, fuel passes via the control valve seat 37 and through outflow bores 35 in the coupler housing 33 into the actuator chamber 23, in which the piezoactuator is also arranged. As a result of the pressure reduction of the fuel, the fuel has a relatively high temperature. In this case, the more the fuel heats up, the higher the system pressure or the operating pressure of the fuel injector 1 is, since In this case, a particularly large pressure reduction associated with a particularly large increase in temperature of the fuel associated.

Um die Bauteilebelastung am Piezoaktor im Aktorraum 23 möglichst gering zu halten ist es bei einem in der Fig. 2 dargestellten erfindungsgemäßen Kraftstoffinjektor 100 vorgesehen, dass der über den Steuerventilsitz 37 in Richtung des Kopplerkörpers 33 strömende Kraftstoff zumindest teilweise, vorzugsweise jedoch vollständig über einen oder mehrere Ausleitkanäle 60 in den Ringraum 5 geführt bzw. ausgeleitet wird. Hierbei ist in der Fig. 2 lediglich ein einziger Ausleitkanal 60 dargestellt, der radial zur Längsachse der Ventilplatte 4 angeordnet ist. Der Ausleitkanal 60 befindet sich dabei in einem in Bezug auf den Kraftstoffinjektor 100 oberen Endbereich der Ventilplatte 4.In order to keep the component load on the piezoelectric actuator in the actuator chamber 23 as low as possible it is at a in the Fig. 2 fuel injector 100 according to the invention provided that the fuel flowing through the control valve seat 37 in the direction of the coupler body 33 at least partially, but preferably completely guided or discharged via one or more diversion channels 60 in the annular space 5. Here is in the Fig. 2 only a single diversion channel 60 is shown, which is arranged radially to the longitudinal axis of the valve plate 4. The diversion channel 60 is located in an upper end region of the valve plate 4 with respect to the fuel injector 100.

Besonders vorteilhaft ist es, wenn die in der Fig. 1 dargestellten Abströmbohrungen 35 entfallen. In diesem Fall wird die komplette, über den geöffneten Ventilsitz 37 abströmende Kraftstoffmenge über den Ausleitkanal 60 in den Ringraum 5 geführt.It is particularly advantageous if the in the Fig. 1 illustrated discharge holes 35 omitted. In this case, the complete amount of fuel flowing out via the open valve seat 37 is led via the diversion channel 60 into the annular space 5.

Weiterhin erkennt man in der Fig. 2 im mittleren Bereich der Drosselplatte 6 auf der dem Ausleitkanal gegenüberliegenden Seite einen Rückleitkanal 61, der vom Rand der Drosselplatte 6 radial nach innen ragt, und der über einen senkrecht angeordneten Rückleitkanalabschnitt 62 Verbindung mit einer umlaufenden Ringnut 63 hat, die an der der Drosselplatte 6 zugewandten Stirnseite der Ventilplatte 4 ausgebildet ist, und die vorzugsweise auf der dem Rücklaufkanalabschnitt 62 gegenüberliegenden Seite hydraulisch mit einer insbesondere in der Fig. 4 erkennbaren Steigleitung 64 Verbindung hat, die im Bereich der Ventilplatte 6 ausgebildet ist. Die Steigleitung 64 hat wiederum hydraulische Verbindung mit einer im Haltekörper 2 ausgebildeten Rücklaufbohrung 65, die mit einem nicht dargestellten Rücklaufanschluss des Kraftstoffinjektors 100 verbunden ist. Ferner erkennt man an der Fig. 2 noch, dass der Leckageraum 54 über einen Leckölablauf 45a mit dem Rücklaufkanal 61 verbunden ist.Furthermore one recognizes in the Fig. 2 in the central region of the throttle plate 6 on the opposite side of the discharge channel a return duct 61 which projects radially inwardly from the edge of the throttle plate 6, and via a vertically arranged Rückleitkanalabschnitt 62 connection with a circumferential annular groove 63 which facing the throttle plate 6 Front side of the valve plate 4 is formed, and preferably on the return channel portion 62 opposite side hydraulically with a particular in the Fig. 4 recognizable riser 64 has connection, which is formed in the region of the valve plate 6. The riser 64 in turn has hydraulic connection with a retaining body 2 formed in the return bore 65 which is connected to a return port, not shown, of the fuel injector 100. Furthermore one recognizes at the Fig. 2 nor that the leakage chamber 54 is connected via a drainage drain 45a to the return channel 61.

Beim Betrieb des Kraftstoffinjektors 100 gelangt über den Steuerventilsitz 37 in Richtung des Kopplerkörpers 33 ausströmender Kraftstoff zunächst über den Ausleitkanal 60 in den Ringraum 5 und von dort über den Rücklaufkanal 61 und den Rücklaufkanalabschnitt 62 in die Ringnut 63, von wo der Kraftstoff über die Steigleitung 64 und die Rücklaufbohrung 65 aus dem Kraftstoffinjektor 100 abgeführt wird. Dadurch, dass der Kraftstoff insbesondere durch den Ringraum 5 strömt, findet eine Abkühlung bzw. Temperaturerniedrigung des Kraftstoffes statt, bevor er in den Bereich des Haltekörpers 2 gelangt. Dasselbe gilt auch für den aus dem Leckageraum 54 ausströmenden Kraftstoff, der sich insbesondere mit dem bereits im Ringraum 5 befindlichen bzw. den Ringraum 5 durchströmenden Kraftstoff mischt.During operation of the fuel injector 100 via the control valve seat 37 in the direction of the coupler body 33 escaping fuel first via the discharge channel 60 into the annular space 5 and from there via the return channel 61 and the return channel section 62 into the annular groove 63, from where the fuel on the Riser 64 and the return bore 65 is discharged from the fuel injector 100. Due to the fact that the fuel flows in particular through the annular space 5, cooling or temperature reduction of the fuel takes place before it reaches the area of the holding body 2. The same also applies to the fuel flowing out of the leakage chamber 54, which mixes in particular with the fuel already flowing in the annular space 5 or through the annular space 5.

Ergänzend wird erwähnt, dass anstelle des Leckölablaufs 45a der Leckageraum 54 auch entsprechend dem Stand der Technik (vgl. Fig. 1) über einen Leckölablauf 45 verfügen kann.In addition, it is mentioned that instead of the leakage oil outlet 45a of the leakage chamber 54 also according to the prior art (see. Fig. 1 ) may have a leakage drain 45.

In der Fig. 3 ist eine alternative Strömungsführung zum Abführen von Kraftstoff aus dem Leckageraum 54 dargestellt.In the Fig. 3 an alternative flow guide for removing fuel from the leakage chamber 54 is shown.

Hierbei weist die Strömungsführung entsprechend der Fig. 2 einen Leckölablauf 45a auf, der über einen in der Drosselplatte 6 radial angeordneten Ausleitkanal 71 Verbindung mit dem Ringraum 5 hat. In der Ventilplatte 4 ist in einem oberen axialen Bereich ein radial angeordneter Rückleitkanal 72 ausgebildet, der ebenfalls Verbindung mit dem Ringraum 5 hat, und der in die Steigleitung 64 mündet. Somit kann im Leckageraum 54 vorhandener, aufgrund der Druckreduzierung eine relativ hohe Temperatur aufweisender Kraftstoff über den Ausleitkanal 71 und dem Ringraum 5 in den Rückleitkanal 72 gelangen, wobei durch die Strömungsführung in dem Ringraum 5 eine Abkühlung des Kraftstoffs stattfindet. Über den Rückleitkanal 72 gelangt der Kraftstoff anschließend über die Rücklaufbohrung 65 in den Kraftstoffrücklauf der Brennkraftmaschine.Here, the flow guide according to the Fig. 2 a drainage 45a, which has a connection in the throttle plate 6 radially arranged discharge 71 with the annular space 5. In the valve plate 4, a radially arranged Rückleitkanal 72 is formed in an upper axial region, which also has connection with the annular space 5, and which opens into the riser 64. Thus, existing in the leakage chamber 54, due to the pressure reduction, a relatively high temperature having fuel via the discharge channel 71 and the annular space 5 in the return passage 72, wherein the flow guidance in the annulus 5, a cooling of the fuel takes place. About the return passage 72 of the fuel then passes through the return bore 65 in the fuel return of the engine.

Zusätzlich wird erwähnt, dass in der Fig. 3 im Bereich des Haltekörpers 2 noch ein Flächenfreilegungsbereich 73 ausgebildet ist, der eine hydraulische Verbindung zwischen dem Aktoraum 23 und der Rücklaufbohrung 65 ausbildet.In addition it is mentioned that in the Fig. 3 In the region of the holding body 2, a surface exposure region 73 is still formed, which forms a hydraulic connection between the actuator chamber 23 and the return bore 65.

In der Fig. 4 ist eine gegenüber der Fig. 3 modifizierte Strömungsführung für den Kraftstoff aus dem Leckageraum 54 dargestellt. Hierbei gelangt der Kraftstoff über den Leckölablauf 45a und den Ausleitkanal 71 ebenfalls in den Ringraum 5. Im Unterschied zur Fig. 3 ist in der Fig. 4 der Rückleitkanal 75, bestehend aus den Teilkanalabschnitten 76, 77 in der Drosselplatte 6 ausgebildet, der ebenso Verbindung mit dem Ringraum 5 hat, und der in der Steigleitung 64 mündet. Dabei kann es vorgesehen sein, dass der vertikale Teilkanalabschnitt 76 des Rückleitkanals 75 nicht konzentrisch zur Steigleitung 64 ist, sondern in einem gewissen Versatz hierzu angeordnet ist. Im Bereich der Ringnut 63 kann ein (nicht dargestellter) Trennsteg in dem vorzugsweise kürzerem Abstand zwischen dem vertikalen Teilkanalabschnitt 76 und der Steigleitung 64 vorhanden sein, so dass der Kraftstoff einen möglichst langen Strömungsweg bis zum Eintritt in die Steigleitung 64 hat.In the Fig. 4 is one opposite the Fig. 3 modified flow guidance for the fuel from the leakage chamber 54 shown. In this case, the fuel also passes through the leakage oil drain 45a and the discharge channel 71 into the annulus 5. In contrast to Fig. 3 is in the Fig. 4 the return channel 75, consisting of the partial channel sections 76, 77 formed in the throttle plate 6, the same Has connection with the annular space 5, and which opens into the riser 64. It may be provided that the vertical part of the channel section 76 of the return channel 75 is not concentric with the riser 64, but is arranged in a certain offset to this. In the region of the annular groove 63, a separating web (not shown) may be present in the preferably shorter distance between the vertical partial channel section 76 and the riser 64, so that the fuel has as long a flow path as possible until it enters the riser 64.

Der soweit beschriebene erfindungsgemäße Kraftstoffinjektor 100 kann in vielfältiger Art und Weise abgewandelt bzw. modifiziert werden, ohne vom Erfindungsgedanken abzuweichen. Denkbare Modifikationen des Kraftstoffinjektors 100 können z.B. derart sein, dass lediglich der in dem Leckageraum 54 befindliche Kraftstoff über den Ringraum 5 geführt wird. Zuletzt ist es auch denkbar, die Ableitung des Kraftstoffes aus dem Ringraum 5 über eine in dem Haltekörper 2 ausgebildete Radialbohrung oder eine in einer Stirnfläche des Haltekörpers 2 ausgebildete, radial verlaufende Nut direkt in die Rücklaufbohrung 65 auszubilden. The fuel injector 100 according to the invention thus far described can be modified or modified in many ways without departing from the spirit of the invention. Conceivable modifications of the fuel injector 100 may be e.g. be such that only the fuel in the leakage chamber 54 is passed through the annulus 5. Finally, it is also conceivable to form the discharge of the fuel from the annular space 5 via a formed in the holding body 2 radial bore or formed in an end face of the holding body 2, radially extending groove directly into the return bore 65.

Claims (10)

  1. Fuel injector (100), having a holding body (2) and having a nozzle body (8) which is braced axially against the holding body (2) by means of a nozzle clamping nut (9) with the interposition of a throttle plate (6) and a valve plate (4), wherein, in the valve plate (4), a control valve (30) which is switchable between at least two switching positions is arranged in a control valve chamber (31), which control valve can be actuated by means of an actuator, preferably in the form of a piezo actuator, arranged in an actuator chamber (23) of the holding body (2), wherein the actuator chamber (23) can be flowed through by fuel which, via a connection (73), is hydraulically coupled to a return bore (65), and wherein a return quantity of fuel emerging from the control valve chamber (31) during the switching of the control valve (30) and/or a return quantity of the fuel emerging from the control valve chamber (31) during the switching intervals of the control valve (30) can be channelled off at least indirectly into the return bore (65) via a further connection,
    characterized
    in that the further connection has a flow path which comprises the ring-shaped chamber (5) between the nozzle clamping nut (9) and the nozzle body (8) and/or the valve plate (4) and/or the throttle plate (6).
  2. Fuel injector according to Claim 1,
    characterized
    in that the further connection comprises a channelling-out duct (60) into the ring-shaped chamber (5) and a return-channelling duct (61) out of the ring-shaped chamber (5), wherein the return-channelling duct (61) issues at least indirectly into the return bore (65).
  3. Fuel injector according to Claim 2,
    characterized
    in that the channelling-out duct (60) and the return-channelling duct (61) are at least substantially formed as ducts arranged radially with respect to the longitudinal axis of the valve plate (4).
  4. Fuel injector according to Claim 2 or 3,
    characterized
    in that the channelling-out duct (60) and the return-channelling duct (61) are arranged on mutually opposite sides of the assembly composed of valve plate (4), throttle plate (6) and nozzle body (8).
  5. Fuel injector according to one of Claims 1 to 4,
    characterized
    in that the further flow path comprises a ring-shaped groove (63) formed on a face side of the valve plate (4) and/or of the throttle plate (6).
  6. Fuel injector according to Claim 5,
    characterized
    in that a separating element, in particular in the form of a separating web, is arranged in the ring-shaped groove (63).
  7. Fuel injector according to one of Claims 1 to 6,
    characterized
    in that a part of the control quantity flows off from the control valve chamber (31) into the actuator chamber (23).
  8. Fuel injector according to Claim 1,
    characterized
    in that the connection has an outflow (45a) which issues into a channelling-out duct (71).
  9. Fuel injector according to Claim 8,
    characterized
    in that the channelling-out duct (71) issues, via the ring-shaped chamber (5) and a return-channelling duct (72, 75), into a rising line (64) which is connected to the return line (65), or in that the ring-shaped chamber (5) is connected to the return line (65) via a flow path which is formed in the holding body (2).
  10. Fuel injector according to one of Claims 1 to 9,
    characterized
    in that the maximum system pressure in the fuel injector (100) is greater than 2000 bar.
EP12720199.4A 2011-06-30 2012-05-11 Fuel injector Active EP2726728B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE102011078381 2011-06-30
DE102011081643A DE102011081643A1 (en) 2011-06-30 2011-08-26 fuel injector
PCT/EP2012/058808 WO2013000618A1 (en) 2011-06-30 2012-05-11 Fuel injector

Publications (2)

Publication Number Publication Date
EP2726728A1 EP2726728A1 (en) 2014-05-07
EP2726728B1 true EP2726728B1 (en) 2015-11-04

Family

ID=47355064

Family Applications (1)

Application Number Title Priority Date Filing Date
EP12720199.4A Active EP2726728B1 (en) 2011-06-30 2012-05-11 Fuel injector

Country Status (3)

Country Link
EP (1) EP2726728B1 (en)
DE (1) DE102011081643A1 (en)
WO (1) WO2013000618A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102018211679A1 (en) * 2018-07-12 2020-01-16 Robert Bosch Gmbh Fuel injector and method for operating a fuel injector

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102007017126A1 (en) * 2007-04-11 2008-10-16 Robert Bosch Gmbh Injection Module
DE102008001330A1 (en) 2008-04-23 2009-10-29 Robert Bosch Gmbh Fuel injection valve for internal combustion engines
DE102009001099A1 (en) * 2009-02-24 2010-08-26 Robert Bosch Gmbh Fuel injection valve for internal-combustion engine, has valve unit partially guided in sleeve, and spring element surrounding sleeve and subjecting sleeve with compressive force for position fixation in axial and/or radial directions
DE102009027494A1 (en) * 2009-07-07 2011-01-13 Robert Bosch Gmbh Fuel injector with pressure compensated control valve
DE102009055267A1 (en) * 2009-12-23 2011-06-30 Robert Bosch GmbH, 70469 Pressure compensated fuel injector with bypass and minimized valve volume
DE102010040381A1 (en) 2010-09-08 2012-03-08 Robert Bosch Gmbh Fuel injector and fuel injection system with at least one fuel injector

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WO2013000618A1 (en) 2013-01-03
EP2726728A1 (en) 2014-05-07

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