EP2256332B1 - Fuel injector with pressure intensifier piston - Google Patents

Fuel injector with pressure intensifier piston Download PDF

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Publication number
EP2256332B1
EP2256332B1 EP10158114.8A EP10158114A EP2256332B1 EP 2256332 B1 EP2256332 B1 EP 2256332B1 EP 10158114 A EP10158114 A EP 10158114A EP 2256332 B1 EP2256332 B1 EP 2256332B1
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EP
European Patent Office
Prior art keywords
pressure
piston
pressure piston
low
fuel injector
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
EP10158114.8A
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German (de)
French (fr)
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EP2256332A3 (en
EP2256332A2 (en
Inventor
Christoph Buehler
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Robert Bosch GmbH
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Robert Bosch GmbH
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Publication of EP2256332A2 publication Critical patent/EP2256332A2/en
Publication of EP2256332A3 publication Critical patent/EP2256332A3/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
    • F02M57/00—Fuel-injectors combined or associated with other devices
    • F02M57/02—Injectors structurally combined with fuel-injection pumps
    • F02M57/022—Injectors structurally combined with fuel-injection pumps characterised by the pump drive
    • F02M57/025—Injectors structurally combined with fuel-injection pumps characterised by the pump drive hydraulic, e.g. with pressure amplification
    • 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
    • F02M47/025—Hydraulically 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
    • F02M57/00—Fuel-injectors combined or associated with other devices
    • F02M57/02—Injectors structurally combined with fuel-injection pumps
    • F02M57/022—Injectors structurally combined with fuel-injection pumps characterised by the pump drive
    • F02M57/025—Injectors structurally combined with fuel-injection pumps characterised by the pump drive hydraulic, e.g. with pressure amplification
    • F02M57/026—Construction details of pressure amplifiers, e.g. fuel passages or check valves arranged in the intensifier piston or head, particular diameter relationships, stop members, arrangement of ports or conduits

Definitions

  • fuel injectors that have a pressure booster piston to boost the pressure of the fuel before injecting beyond the system pressure of the fuel system are off DE 10 2004 053 421 A1 and DE 10 2007 002 760 A1 known.
  • DE 10 2007 000 150 A1 discloses an injector having a boost mechanism and a nozzle.
  • the boost mechanism amplifies a fuel and the nozzle injects and feeds the fuel boosted by the boost mechanism.
  • the reinforcing mechanism has a tubular piston and a columnar piston.
  • the tubular piston has a bore extending through the tubular piston in a direction of a longitudinal axis of the tubular piston.
  • the columnar piston is loosely received in the tubular piston and has an end portion projecting from the tubular piston and engaged with the tubular piston.
  • the tubular piston is slidably received in a first cylinder.
  • the end portion of the columnar piston is slidably received in a second cylinder which is generally coaxial with the first cylinder and which has a diameter different from the diameter of the first cylinder.
  • WO 02/092998 A1 discloses a fuel injector for internal combustion engines having a fuel injector which can be supplied by a high-pressure fuel source, wherein a pressure booster having a movable piston is connected between the fuel injector and the high-pressure fuel source, and wherein the movable piston has a space connected to the high-pressure fuel source from a high-pressure space connected to the injector and from a rear space separates.
  • the high pressure chamber is connectable via a fuel line to the rear space.
  • Such a check valve reliably prevents a backflow of the fuel from the high-pressure region into the low-pressure region of the fuel injector.
  • a fuel injector according to the invention has a low-pressure piston and a high-pressure piston, wherein the high-pressure piston has a smaller diameter than the low-pressure piston.
  • the low-pressure piston is a parallel formed to the longitudinal direction of the low-pressure piston bore and a portion of the high pressure piston is disposed in the bore.
  • a pressure intensifier piston comprising a high-pressure piston and a low-pressure piston prevents hydraulic forces acting on the pressure intensifier piston from tilting the pressure intensifier piston in a bore surrounding it. Seizure of the pressure booster piston is thus reliably prevented and the wear of the pressure intensifier piston is reduced.
  • Coaxial honing and / or a special friction reducing coating of the intensifier piston is not required.
  • the requirements for the coaxiality of the piston with the surrounding bore, the concentricity and the parallelism are reduced.
  • the high pressure and low pressure pistons are coaxial with one another. This allows a simple construction and the use of a two-part pressure booster piston according to the invention in a conventional fuel injector.
  • the high pressure piston and the low pressure piston are connected by a coupling, the coupling being adapted to transmit forces in the axial direction, i. are aligned parallel to the longitudinal direction of the piston, is formed between the piston.
  • the coupling is formed as a shoulder on the circumference of the high-pressure piston and the low-pressure piston abuts against the shoulder.
  • a recess is formed in the periphery of the high-pressure piston, in which a coupling element, e.g. is designed as a ring surrounding the high-pressure piston, is mounted.
  • the coupling is formed as a hydraulic seal, which is sealed by the large forces acting on the piston axial forces.
  • a hydraulic seal allows hydraulic separation between the high pressure region and the low pressure region of the fuel injector.
  • an O-ring is additionally disposed between the high-pressure piston and the low-pressure piston in order to improve the sealing effect.
  • At least one of the pistons is formed substantially cylindrical. This allows a simple production of the piston and the use of a two-part pressure booster piston according to the invention in a conventional fuel injector.
  • a portion of the high pressure piston is disposed in the bore of the low pressure piston with radial play. Due to the radial clearance, the pistons are mechanically separated from each other and acting in the radial direction hydraulic shear forces are significantly reduced.
  • the clearance between the high-pressure piston and the low-pressure piston should be between 10 and 20 ⁇ m, preferably 15 ⁇ m.
  • the high pressure piston and the low pressure piston are manufactured to a fixed size plus tolerance. Thereafter, the respective holes for the high-pressure piston and for the low-pressure piston are made so that the desired game is created; i.e. High pressure piston and low pressure piston are paired. Thus, the desired game on the high-pressure piston and the low-pressure piston can be optimally adjusted.
  • FIG. 1 shows a section of a fuel injector 2 according to the invention in a sectional view.
  • the fuel injector 2 has a first injector body 32 and a second injector body 34, which are clamped hydraulically tight by a clamping nut 36.
  • a differential pressure space 14 and a compression space 24 are formed, which extend coaxially in the longitudinal direction of the fuel injector 2.
  • the compression chamber 24 has a smaller cross section than the differential pressure chamber 14 and is provided with a drain 26, the hydraulic compression chamber 24 with a in the FIG. 1 Not shown nozzle needle control chamber connects.
  • a working space 12 is formed, which has the same cross-section as the differential pressure chamber 14 and is arranged coaxially to the differential pressure chamber 14 when the first injector body 32 is clamped to the second injector body 34.
  • the working space 12 can be filled with fuel from an external fuel source by means of a fuel supply 10 formed in the second injector body 34.
  • control valve 28 On the side facing away from the first injector body 32 side of the second injector body 34 is a control valve 28.
  • the control valve 28 is connected via a working space line 30 and a differential pressure chamber 16 each hydraulically connected to the working space 12 and the differential pressure chamber 14.
  • a high-pressure piston 6 extends parallel to the longitudinal direction of the fuel injector 2 through the working chamber 12, the differential pressure chamber 14 and the compression chamber 24.
  • the high-pressure piston 6 an axially extending in the longitudinal direction of the high-pressure piston 6 fuel passage 20 is formed, which via hydraulic openings 40 hydraulically with the working space 12 is connected.
  • the cross-section of the high-pressure piston 6 is selected such that the high-pressure piston 6 is fitted into the compression space 24 and seals it hydraulically in a sealed manner.
  • the high pressure piston 6 has a smaller cross section than the working space 12 and as the differential pressure chamber 14 and is surrounded in the region of the working chamber 12 by a piston spring 18 which supports the high pressure piston 6 elastically on the first injector body 32. Between the first injector body 32 and the piston spring 18, a washer 38 is provided. By choosing the thickness of the washer 38, the force exerted by the piston spring 18 on the high-pressure piston 6, adjustable.
  • a check valve 22 is formed in the high-pressure piston 6.
  • the check valve 22 allows the flow of fuel from the fuel passage 20 into the compression space 24 and prevents the backflow of fuel from the compression space 24 into the fuel passage 20.
  • the high-pressure piston 6 In a region of the differential pressure chamber 14 adjoining the working space 12, the high-pressure piston 6 is surrounded by a low-pressure piston 4.
  • the low-pressure piston 4 is supported on a coupling 8 which is formed on the circumference of the high-pressure piston 6 from.
  • the coupling 8 is designed such that an axial force acting in the direction of the differential pressure chamber 14 and acting on the low-pressure piston 4 can be transmitted to the high-pressure piston 6.
  • the high pressure piston 6 is movable by moving the low pressure piston 4 in the direction of the differential pressure chamber 14.
  • the coupling 8 is designed as a hydraulic seal which seals the differential pressure chamber 14 with respect to the working space 12 hydraulically, so that a pressure difference between the differential pressure chamber 14 and the working space 12 can be constructed and maintained.
  • the differential pressure chamber 14 is delimited on the side facing the working chamber 12 by a first annular pressure surface 42 of the low-pressure piston 4.
  • the volume of the differential pressure space 14 is variable by moving the low-pressure piston 16 in the longitudinal direction of the fuel injector 2.
  • the working space 12 is hydraulically connected to the differential pressure chamber 14 via the working space line 30 and the differential pressure space line 16.
  • the differential pressure chamber 14 is connected via the differential pressure chamber line 16 with a fuel return 29.
  • the compression space 24 is delimited on the side facing the differential pressure chamber 14 by an end face 61 of the high-pressure piston 6, so that the volume of the compression space 24 can be varied by moving the high-pressure piston 6.
  • the compression chamber 23 from the working space 12 can be filled with fuel. In order to avoid that fuel from the compression chamber 24 flows through the fuel passage 20 back into the working space 12, the fuel passage 20 is blocked by the check valve 24 in this flow direction.
  • nozzle needle of the fuel injector 2 is movable by changing the pressure in the nozzle needle control space between a closed position in which no fuel is injected from the fuel injector 2 into a surrounding combustion chamber and an opened injection position.
  • the control valve 28 is switched so that the connection from the differential pressure chamber 14 via the differential pressure chamber line 16 is released into the fuel return 29 and the pressure in the differential pressure chamber 14 decreases.
  • the system pressure prevailing from the fuel supply continues to prevail, so that the pressure force prevailing there, which acts on a second pressure surface 41 of the low-pressure piston 4 facing the working space 12, is greater than the sum of the forces acting on the first, the differential pressure space 14 facing pressure surface 42 of the low-pressure piston 4 and the end face 61 of the high-pressure piston 6 act.
  • the low-pressure piston 4 is displaced into the compression space 19 by the resulting force. Via the coupling 8, the low-pressure piston 4 presses the high-pressure piston 6 into the compression space 24. The volume of the compression space 24 is reduced and the fuel present in the compression space 24 is compressed, so that the pressure in the compression space 24 is increased beyond the system pressure to the desired injection pressure , The thus compressed and high pressure fuel flows from the compression chamber 24 through the drain 26 into the nozzle space, not shown.
  • a second control valve is activated in such a way that the pressure in the nozzle needle control chamber decreases.
  • the pressure acting on the nozzle needle pressure in the nozzle chamber then exceeds the closing pressure in the nozzle needle control chamber.
  • the nozzle needle lifts off the valve seat and fuel is injected into the combustion chamber of the internal combustion engine with the injection pressure boosted by the high-pressure piston 6 beyond the system pressure.
  • the second control valve is switched so that the pressure in the nozzle needle control chamber increases to the injection pressure and the nozzle needle is pushed back into the valve seat, in which it closes the injection opening (s).
  • control valve 28 is switched so that it releases the connection from the working space 12 via the working space line 30 and the differential pressure space line 16 into the differential pressure space 14.
  • Fuel under system pressure flows out of the working chamber 12 into the differential pressure chamber 14.
  • system pressure builds up again and pushes the low-pressure piston 4 back into its starting position.
  • FIG. 2 shows a perspective view of a section of a fuel injector 2 according to the invention in the FIG. 2 only the first injector body 32 with the two-part pressure booster piston 4, 6 arranged therein is shown.
  • the second injector body 34, the clamping nut 36, the piston spring 18 and the control valve 28 are not shown for reasons of clarity.
  • FIG. 2 shown components are denoted by the same reference numerals as in the FIG. 1 designated.
  • the simple structure of a pressure booster piston 4, 6 according to the invention is in the FIG. 2 particularly recognizable.
  • the differential pressure space line 19 is in the in the FIG. 2 Not shown part of the first injector body 32 is formed and therefore in the FIG. 2 not visible.

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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

Kraftstoffinjektoren, die einen Druckverstärkerkolben haben, um den Druck des Kraftstoffs vor dem Einspritzen über den Systemdruck des Kraftstoffsystems hinaus zu verstärken, sind z.B. aus DE 10 2004 053 421 A1 und DE 10 2007 002 760 A1 bekannt.For example, fuel injectors that have a pressure booster piston to boost the pressure of the fuel before injecting beyond the system pressure of the fuel system are off DE 10 2004 053 421 A1 and DE 10 2007 002 760 A1 known.

In solchen Kraftstoffinjektoren tritt über die Länge des Druckverstärkerkolbens ein stark variierender Druckverlauf mit an beiden Enden des Kolbens entgegengesetzt angreifenden Kräften auf, die bestrebt sind, den Kolben zu verkippen. Ein Verkippen erhöht den Verschleiß und die Gefahr, dass der Kolben in der ihn umgebenden Bohrung verkantet. Um den Verschleiß zu verringern, wird der Umfang des Kolbens häufig mit einer Reibung verringernden Beschichtung versehen. Das Aufbringen einer solche Beschichtung verursacht zusätzliche Kosten und einen erhöhten Fertigungsaufwand.In such fuel injectors, over the length of the pressure intensifier piston, a widely varying pressure pattern occurs with opposing forces acting on both ends of the piston, which tend to tilt the piston. Tilting increases wear and the risk of the piston tilting in the surrounding hole. To reduce wear, the periphery of the piston is often provided with a friction reducing coating. The application of such a coating causes additional costs and increased production costs.

DE 10 2007 000 150 A1 offenbart eine Einspritzvorrichtung mit einem Verstärkungsmechanismus und einer Düse. Der Verstärkungsmechanismus verstärkt einen Kraftstoff, und die Düse spritzt den durch den Verstärkungsmechanismus verstärkten Kraftstoff ein und führt ihn zu. Der Verstärkungsmechanismus hat einen röhrenartigen Kolben und einen säulenartigen Kolben. Der röhrenartige Kolben hat eine Bohrung, die sich durch den röhrenartigen Kolben in einer Richtung einer Längsachse des röhrenartigen Kolbens erstreckt. Der säulenartige Kolben ist in dem röhrenartigen Kolben lose aufgenommen und hat einen Endabschnitt, der von dem röhrenartigen Kolben vorsteht und der mit dem röhrenartigen Kolben in Eingriff ist. Der röhrenartige Kolben ist in einem ersten Zylinder gleitbar aufgenommen. Der Endabschnitt des säulenartigen Kolbens ist in einem zweiten Zylinder gleitbar aufgenommen, der im Allgemeinen koaxial zu dem ersten Zylinder vorgesehen ist, und der einen Durchmesser aufweist, der sich von dem Durchmesser des ersten Zylinders unterscheidet. DE 10 2007 000 150 A1 discloses an injector having a boost mechanism and a nozzle. The boost mechanism amplifies a fuel and the nozzle injects and feeds the fuel boosted by the boost mechanism. The reinforcing mechanism has a tubular piston and a columnar piston. The tubular piston has a bore extending through the tubular piston in a direction of a longitudinal axis of the tubular piston. The columnar piston is loosely received in the tubular piston and has an end portion projecting from the tubular piston and engaged with the tubular piston. The tubular piston is slidably received in a first cylinder. The end portion of the columnar piston is slidably received in a second cylinder which is generally coaxial with the first cylinder and which has a diameter different from the diameter of the first cylinder.

WO 02/092998 A1 offenbart eine Kraftstoffeinspritzeinrichtung für Brennkraftmaschinen mit einem von einer Kraftstoffhochdruckquelle versorgbaren Kraftstoffinjektor, wobei zwischen dem Kraftstoffinjektor und der Kraftstoffhochdruckquelle eine einen beweglichen Kolben aufweisende Druckübersetzungseinrichtung geschaltet ist und wobei der bewegliche Kolben einen an die Kraftstoffhochdruckquelle angeschlossenen Raum von einem mit dem Injektor verbundenen Hochdruckraum sowie von einem Rückraum trennt. Der Hochdruckraum ist über eine Kraftstoffleitung mit dem Rückraum verbindbar. WO 02/092998 A1 discloses a fuel injector for internal combustion engines having a fuel injector which can be supplied by a high-pressure fuel source, wherein a pressure booster having a movable piston is connected between the fuel injector and the high-pressure fuel source, and wherein the movable piston has a space connected to the high-pressure fuel source from a high-pressure space connected to the injector and from a rear space separates. The high pressure chamber is connectable via a fuel line to the rear space.

Offenbarung der ErfindungDisclosure of the invention

Es ist eine Aufgabe der vorliegenden Erfindung, einen verbesserten Druck verstärkenden Kraftstoffinjektor bereit zu stellen, der wenig verschleißt und kostengünstig herstellbar ist.It is an object of the present invention to provide an improved pressure boosting fuel injector that is low in wear and inexpensive to manufacture.

Die Aufgabe wird von einem erfindungsgemäßen Kraftstoffinjektor gemäß dem unabhängigen Patentanspruch 1 gelöst. Die abhängigen Patentansprüche beschreiben vorteilhafte Ausgestaltungen des erfindungsgemäßen Kraftstoffinjektors nach dem unabhängigen Patentanspruch 1.The object is achieved by a fuel injector according to the invention according to independent claim 1. The dependent claims describe advantageous embodiments of the fuel injector according to the invention according to the independent claim. 1

Ein solches Rückschlagventil verhindert zuverlässig ein Zurückströmen des Kraftstoff aus dem Hochdruckbereich in den Niederdruckbereich des Kraftstoffinjektors.Such a check valve reliably prevents a backflow of the fuel from the high-pressure region into the low-pressure region of the fuel injector.

Ein erfindungsgemäßer Kraftstoffinjektor weist einen Niederdruckkolben und einen Hochdruckkolben auf, wobei der Hochdruckkolben einen kleineren Durchmesser als der Niederdruckkolben hat. In dem Niederdruckkolben ist eine parallel zur Längsrichtung des Niederdruckkolbens verlaufende Bohrung ausgebildet und ein Bereich des Hochdruckkolbens ist in der Bohrung angeordnet.A fuel injector according to the invention has a low-pressure piston and a high-pressure piston, wherein the high-pressure piston has a smaller diameter than the low-pressure piston. In the low-pressure piston is a parallel formed to the longitudinal direction of the low-pressure piston bore and a portion of the high pressure piston is disposed in the bore.

Der erfindungsgemäße Aufbau eines Druckverstärkerkolbens aus einem Hochdruckkolben und einem Niederdruckkolben vermeidet, dass hydraulische Kräfte, die auf den Druckverstärkerkolben wirken, den Druckverstärkerkolben in einer ihn umgebenden Bohrung verkanten. Ein Festfressen des Druckverstärkerkolbens wird so zuverlässig verhindert und der Verschleiß der Druckverstärkerkolben wird reduziert.The construction according to the invention of a pressure intensifier piston comprising a high-pressure piston and a low-pressure piston prevents hydraulic forces acting on the pressure intensifier piston from tilting the pressure intensifier piston in a bore surrounding it. Seizure of the pressure booster piston is thus reliably prevented and the wear of the pressure intensifier piston is reduced.

Ein Koaxialhonen und/oder eine spezielle, Reibung reduzierende Beschichtung des Druckverstärkerkolben sind nicht erforderlich. Die Anforderungen an die Koaxialität des Kolbens mit der umgebenden Bohrung, den Rundlauf und die Parallelität werden vermindert.Coaxial honing and / or a special friction reducing coating of the intensifier piston is not required. The requirements for the coaxiality of the piston with the surrounding bore, the concentricity and the parallelism are reduced.

In einer Ausführungsform sind der Hochdruck- und der Niederdruckkolben koaxial zueinander angeordnet. Dies ermöglicht einen einfachen Aufbau und die Verwendung eines erfindungsgemäßen zweiteiligen Druckverstärkerkolbens in einem herkömmlichen Kraftstoffinjektor.In one embodiment, the high pressure and low pressure pistons are coaxial with one another. This allows a simple construction and the use of a two-part pressure booster piston according to the invention in a conventional fuel injector.

In einer Ausführungsform sind der Hochdruckkolben und der Niederdruckkolben durch eine Kopplung verbunden, wobei die Kopplung zur Übertragung von Kräften, die in axialer Richtung, d.h. parallel zur Längsrichtung des Kolbens, ausgerichtet sind, zwischen den Kolben ausgebildet ist. In einer Ausführungsform ist die Kopplung als Absatz auf dem Umfang des Hochdruckkolbens ausgebildet und der Niederdruckkolben liegt an dem Absatz an. Alternativ ist im Umfang des Hochdruckkolbens eine Vertiefung ausgebildet, in der ein Kopplungselement, das z.B. als um den Hochdruckkolben umlaufender Ring ausgebildet ist, angebracht ist.In one embodiment, the high pressure piston and the low pressure piston are connected by a coupling, the coupling being adapted to transmit forces in the axial direction, i. are aligned parallel to the longitudinal direction of the piston, is formed between the piston. In one embodiment, the coupling is formed as a shoulder on the circumference of the high-pressure piston and the low-pressure piston abuts against the shoulder. Alternatively, a recess is formed in the periphery of the high-pressure piston, in which a coupling element, e.g. is designed as a ring surrounding the high-pressure piston, is mounted.

In einer Ausführungsform ist die Kopplung als hydraulischen Dichtung ausgebildet, die durch die großen auf die Kolben wirkenden Axialkräfte abgedichtet wird. Eine hydraulischen Dichtung ermöglicht eine hydraulische Trennung zwischen dem Hochdruckbereich und dem Niederdruckbereich des Kraftstoffinjektors. In einer Ausführungsform ist zusätzlich ein O-Ring zwischen dem Hochdruckkolben und den Niederdruckkolben angeordnet, um die Dichtwirkung zu verbessern.In one embodiment, the coupling is formed as a hydraulic seal, which is sealed by the large forces acting on the piston axial forces. A hydraulic seal allows hydraulic separation between the high pressure region and the low pressure region of the fuel injector. In one embodiment, an O-ring is additionally disposed between the high-pressure piston and the low-pressure piston in order to improve the sealing effect.

In einer Ausführungsform ist wenigstens einer der Kolben im wesentlichen zylinderförmig ausgebildet ist. Dies ermöglicht eine einfache Herstellung des Kolbens und die Verwendung eines erfindungsgemäßen zweiteiligen Druckverstärkerkolbens in einem herkömmlichen Kraftstoffinjektor.In one embodiment, at least one of the pistons is formed substantially cylindrical. This allows a simple production of the piston and the use of a two-part pressure booster piston according to the invention in a conventional fuel injector.

In einer Ausführungsform ist ein Bereich des Hochdruckkolbens mit radialem Spiel in der Bohrung des Niederdruckkolbens angeordnet. Durch das radiale Spiel sind die Kolben mechanisch voneinander getrennt und in radialer Richtung wirkende hydraulische Querkräfte werden signifikant verringert.In one embodiment, a portion of the high pressure piston is disposed in the bore of the low pressure piston with radial play. Due to the radial clearance, the pistons are mechanically separated from each other and acting in the radial direction hydraulic shear forces are significantly reduced.

Das Spiel zwischen dem Hochdruckkolben und dem Niederdruckkolben sollte zwischen 10 und 20 µm, vorzugsweise 15 µm betragen.The clearance between the high-pressure piston and the low-pressure piston should be between 10 and 20 μm, preferably 15 μm.

In einer Ausführungsform werden der Hochdruckkolben und der Niederdruckkolben auf ein Festmaß plus Toleranz gefertigt. Danach werden die jeweiligen Bohrungen für den Hochdruckkolben und für den Niederdruckkolben so gefertigt, das das gewünschte Spiel entsteht; d.h. Hochdruckkolben und Niederdruckkolben werden gepaart. So kann das gewünschte Spiel am Hochdruckkolben und am Niederdruckkolben optimal eingestellt werden.In one embodiment, the high pressure piston and the low pressure piston are manufactured to a fixed size plus tolerance. Thereafter, the respective holes for the high-pressure piston and for the low-pressure piston are made so that the desired game is created; i.e. High pressure piston and low pressure piston are paired. Thus, the desired game on the high-pressure piston and the low-pressure piston can be optimally adjusted.

Die Erfindung wird im Folgenden anhand der beiliegenden Figuren näher erläutert. Dabei zeigt:

  • Figur 1 eine Schnittdarstellung eines Ausschnitts aus einem erfindungsgemäßen Kraftstoffinjektor, und
  • Figur 2 eine perspektivische Schnittansicht eines erfindungsgemäßen Kraftstoffinjektors.
The invention will be explained in more detail below with reference to the accompanying figures. Showing:
  • FIG. 1 a sectional view of a section of a fuel injector according to the invention, and
  • FIG. 2 a perspective sectional view of a fuel injector according to the invention.

Figur 1 zeigt einen Ausschnitt aus einem erfindungsgemäßen Kraftstoffinjektor 2 in einer Schnittdarstellung. FIG. 1 shows a section of a fuel injector 2 according to the invention in a sectional view.

Der Kraftstoffinjektor 2 weist einen ersten Injektorkörper 32 und einen zweiten Injektorkörper 34 auf, die durch eine Spannmutter 36 hydraulisch dicht verspannt sind.The fuel injector 2 has a first injector body 32 and a second injector body 34, which are clamped hydraulically tight by a clamping nut 36.

In dem ersten Injektorkörper 32 sind ein Differendruckraum 14 und ein Kompressionsraum 24 ausgebildet, die sich koaxial in Längsrichtung des Kraftstoffinjektors 2 erstrecken. Der Kompressionsraum 24 hat einen kleineren Querschnitt als der Differenzdruckraum 14 und ist mit einem Ablauf 26 versehen, der den Kompressionsraum 24 hydraulisch mit einem in der Figur 1 nicht gezeigten Düsennadelsteuerraum verbindet.In the first injector body 32, a differential pressure space 14 and a compression space 24 are formed, which extend coaxially in the longitudinal direction of the fuel injector 2. The compression chamber 24 has a smaller cross section than the differential pressure chamber 14 and is provided with a drain 26, the hydraulic compression chamber 24 with a in the FIG. 1 Not shown nozzle needle control chamber connects.

In dem zweiten Injektorkörper 34 ist ein Arbeitsraum 12 ausgebildet, der den gleichen Querschnitt wie der Differenzdruckraum 14 hat und koaxial zu dem Differenzdruckraum 14 angeordnet ist, wenn der erste Injektorkörper 32 mit dem zweiten Injektorkörper 34 verspannt ist. Der Arbeitsraum 12 ist durch eine in dem zweiten Injektorkörper 34 ausgebildete Kraftstoffzufuhr 10 mit Kraftstoff aus einer externen Kraftstoffquelle befüllbar.In the second injector body 34, a working space 12 is formed, which has the same cross-section as the differential pressure chamber 14 and is arranged coaxially to the differential pressure chamber 14 when the first injector body 32 is clamped to the second injector body 34. The working space 12 can be filled with fuel from an external fuel source by means of a fuel supply 10 formed in the second injector body 34.

Auf der von dem ersten Injektorkörper 32 abgewandten Seite des zweiten Injektorkörpers 34 befindet sich ein Steuerventil 28. Das Steuerventil 28 ist über eine Arbeitsraumleitung 30 und eine Differenzdruckraumleitung 16 jeweils hydraulisch mit dem Arbeitsraum 12 und dem Differenzdruckraum 14 verbunden.On the side facing away from the first injector body 32 side of the second injector body 34 is a control valve 28. The control valve 28 is connected via a working space line 30 and a differential pressure chamber 16 each hydraulically connected to the working space 12 and the differential pressure chamber 14.

Ein Hochdruckkolben 6 erstreckt sich parallel zur Längsrichtung des Kraftstoffinjektors 2 durch den Arbeitsraum 12, den Differenzdruckraum 14 und den Kompressionsraum 24. In dem Hochdruckkolben 6 ist ein axial in Längsrichtung des Hochdruckkolbens 6 verlaufender Kraftstoffkanal 20 ausgebildet, der über radiale Öffnungen 40 hydraulisch mit dem Arbeitsraum 12 verbunden ist.A high-pressure piston 6 extends parallel to the longitudinal direction of the fuel injector 2 through the working chamber 12, the differential pressure chamber 14 and the compression chamber 24. In the high-pressure piston 6, an axially extending in the longitudinal direction of the high-pressure piston 6 fuel passage 20 is formed, which via hydraulic openings 40 hydraulically with the working space 12 is connected.

Der Querschnitt des Hochdruckkolbens 6 ist so gewählt, dass der Hochdruckkolben 6 in den Kompressionsraum 24 eingepasst ist und diesen hydraulisch dicht verschließt. Der Hochdruckkolben 6 hat einen kleinere Querschnitt als der Arbeitsraum 12 und als der Differenzdruckraum 14 und ist im Bereich des Arbeitsraums 12 von einer Kolbenfeder 18 umgeben, die den Hochdruckkolben 6 elastisch an dem ersten Injektorkörper 32 abstützt. Zwischen dem ersten Injektorkörper 32 und der Kolbenfeder 18 ist eine Unterlegscheibe 38 vorgesehen. Durch die Wahl der Dicke der Unterlegscheibe 38 ist die Kraft, welche die Kolbenfeder 18 auf den Hochdruckkolben 6 ausübt, einstellbar.The cross-section of the high-pressure piston 6 is selected such that the high-pressure piston 6 is fitted into the compression space 24 and seals it hydraulically in a sealed manner. The high pressure piston 6 has a smaller cross section than the working space 12 and as the differential pressure chamber 14 and is surrounded in the region of the working chamber 12 by a piston spring 18 which supports the high pressure piston 6 elastically on the first injector body 32. Between the first injector body 32 and the piston spring 18, a washer 38 is provided. By choosing the thickness of the washer 38, the force exerted by the piston spring 18 on the high-pressure piston 6, adjustable.

An dem in der Figur 1 rechts dargestellten Ende des Kraftstoffkanals 20, das dem Kompressionsraum 24 zugewandt ist, ist in dem Hochdruckkolben 6 ein Rückschlagventil 22 ausgebildet. Das Rückschlagventil 22 ermöglicht den Fluss von Kraftstoff aus dem Kraftstoffkanal 20 in den Kompressionsraum 24 und verhindert den Rückfluss von Kraftstoff aus dem Kompressionsraum 24 in den Kraftstoffkanal 20.At the in the FIG. 1 Right end of the fuel channel 20, which faces the compression space 24, a check valve 22 is formed in the high-pressure piston 6. The check valve 22 allows the flow of fuel from the fuel passage 20 into the compression space 24 and prevents the backflow of fuel from the compression space 24 into the fuel passage 20.

In einem an den Arbeitsraum 12 angrenzenden Bereich des Differenzdruckraums 14 ist der Hochdruckkolben 6 von einem Niederdruckolben 4 umgeben. Der Niederdruckkolben 4 stützt sich an einer Kopplung 8, die am Umfang des Hochdruckkolbens 6 ausgebildet ist, ab. Die Kopplung 8 ist so ausgebildet, dass eine in Richtung auf den Differenzdruckraum 14 ausgerichtete auf den Niederdruckkolben 4 wirkende axiale Kraft auf den Hochdruckkolben 6 übertragbar ist. Der Hochdruckkolben 6 ist durch Bewegen des Niederdruckkolben 4 in Richtung auf den Differenzdruckraum 14 bewegbar.In a region of the differential pressure chamber 14 adjoining the working space 12, the high-pressure piston 6 is surrounded by a low-pressure piston 4. The low-pressure piston 4 is supported on a coupling 8 which is formed on the circumference of the high-pressure piston 6 from. The coupling 8 is designed such that an axial force acting in the direction of the differential pressure chamber 14 and acting on the low-pressure piston 4 can be transmitted to the high-pressure piston 6. The high pressure piston 6 is movable by moving the low pressure piston 4 in the direction of the differential pressure chamber 14.

Die Kopplung 8 ist als hydraulische Dichtung ausgebildet, die den Differenzdruckraum 14 gegenüber dem Arbeitsraum 12 hydraulisch abdichtet, so dass ein Druckunterschied zwischen dem Differenzdruckraum 14 und dem Arbeitsraum 12 aufgebaut und aufrecht erhalten werden kann.The coupling 8 is designed as a hydraulic seal which seals the differential pressure chamber 14 with respect to the working space 12 hydraulically, so that a pressure difference between the differential pressure chamber 14 and the working space 12 can be constructed and maintained.

Der Differenzdruckraum 14 wird auf der dem Arbeitsraum 12 zugewandten Seite von einer ersten ringförmigen Druckfläche 42 des Niederdruckkolbens 4 begrenzt. Das Volumen des Differenzdruckraums 14 ist durch Bewegen des Niederdruckkolbens 16 in Längsrichtung des Kraftstoffinjektors 2 variierbar.The differential pressure chamber 14 is delimited on the side facing the working chamber 12 by a first annular pressure surface 42 of the low-pressure piston 4. The volume of the differential pressure space 14 is variable by moving the low-pressure piston 16 in the longitudinal direction of the fuel injector 2.

In einer ersten Schaltstellung des Steuerventils 28 ist der Arbeitsraum 12 über die Arbeitsraumleitung 30 und die Differenzdruckraumleitung 16 hydraulisch mit dem Differenzdruckraum 14 verbunden.In a first switching position of the control valve 28, the working space 12 is hydraulically connected to the differential pressure chamber 14 via the working space line 30 and the differential pressure space line 16.

In einer zweiten Schaltstellung des Steuerventils 28 ist der Differenzdruckraum 14 über die Differenzdruckraumleitung 16 mit einem Kraftstoffrücklauf 29 verbunden.In a second switching position of the control valve 28, the differential pressure chamber 14 is connected via the differential pressure chamber line 16 with a fuel return 29.

Der Kompressionsraum 24 wird auf der dem Differenzdruckraum 14 zugewandten Seite durch eine Stirnfläche 61 des Hochdruckkolbens 6 begrenzt, so dass das Volumen des Kompressionsraums 24 durch Bewegen des Hochdruckkolbens 6 variierbar ist. Über den in dem Hochdruckkolben 6 ausgebildeten Kraftstoffkanal 20 und das Rückschlagventil 22 ist der Kompressionsraum 23 aus dem Arbeitsraum 12 mit Kraftstoff befüllbar. Um zu vermeiden, dass Kraftstoff aus dem Kompressionsraum 24 über den Kraftstoffkanal 20 zurück in den Arbeitsraum 12 strömt, ist der Kraftstoffkanal 20 durch das Rückschlagventil 24 in dieser Strömungsrichtung gesperrt.The compression space 24 is delimited on the side facing the differential pressure chamber 14 by an end face 61 of the high-pressure piston 6, so that the volume of the compression space 24 can be varied by moving the high-pressure piston 6. About the formed in the high-pressure piston 6 fuel passage 20 and the check valve 22, the compression chamber 23 from the working space 12 can be filled with fuel. In order to avoid that fuel from the compression chamber 24 flows through the fuel passage 20 back into the working space 12, the fuel passage 20 is blocked by the check valve 24 in this flow direction.

Aus dem Kompressionsraum 24 gelangt Kraftstoff über einen Ablauf 26 in einen nicht gezeigten Düsenraum und einen ebenfalls nicht gezeigten Düsennadelsteuerraum. Die, nicht gezeigte, Düsennadel des Kraftstoffinjektors 2 ist durch eine Veränderung des Drucks im Düsennadelsteuerraum zwischen einer geschlossenen Position, in der kein Kraftstoff aus dem Kraftstoffinjektor 2 in einen umgebenden Brennraum eingespritzt wird, und einer geöffneten Einspritzposition bewegbar.From the compression chamber 24 fuel passes through a drain 26 in a nozzle chamber, not shown, and a nozzle needle control chamber, also not shown. The nozzle needle of the fuel injector 2, not shown, is movable by changing the pressure in the nozzle needle control space between a closed position in which no fuel is injected from the fuel injector 2 into a surrounding combustion chamber and an opened injection position.

Um den Einspritzvorgang zu starten, wird das Steuerventil 28 so geschaltet, dass die Verbindung vom Differenzdruckraum 14 über die Differenzdruckraumleitung 16 in den Kraftstoffrücklauf 29 freigegeben wird und der Druck im Differenzdruckraum 14 abnimmt. Im Arbeitsraum 12 herrscht weiterhin der von der Kraftstoffzufuhr vorgegebene Systemdruck, so dass die dort vorherrschende Druckkraft, die auf eine zweite, dem Arbeitsraum 12 zugewandte Druckfläche 41 des Niederdruckkolbens 4 wirkt, größer als die Summe der Kräfte ist, die auf die erste, dem Differenzdruckraum 14 zugewandte Druckfläche 42 des Niederdruckkolbens 4 und die Stirnfläche 61 des Hochdruckkolbens 6 wirken.To start the injection process, the control valve 28 is switched so that the connection from the differential pressure chamber 14 via the differential pressure chamber line 16 is released into the fuel return 29 and the pressure in the differential pressure chamber 14 decreases. In the working space 12, the system pressure prevailing from the fuel supply continues to prevail, so that the pressure force prevailing there, which acts on a second pressure surface 41 of the low-pressure piston 4 facing the working space 12, is greater than the sum of the forces acting on the first, the differential pressure space 14 facing pressure surface 42 of the low-pressure piston 4 and the end face 61 of the high-pressure piston 6 act.

Der Niederdruckkolben 4 wird von der resultierenden Kraft in den Kompressionsraum 19 hinein verschoben. Über die Kopplung 8 drückt der Niederdruckkolben 4 den Hochdruckkolben 6 in den Kompressionsraum 24. Das Volumen des Kompressionsraum 24 wird verringert und der im Kompressionsraum 24 vorhandene Kraftstoff wird komprimiert, so dass der Druck im Kompressionsraum 24 über den Systemdruck hinaus auf den gewünschten Einspritzdruck verstärkt wird. Der so komprimierte und unter hohem Druck stehende Kraftstoff strömt aus dem Kompressionsraum 24 durch den Ablauf 26 in den nicht gezeigten Düsenraum.The low-pressure piston 4 is displaced into the compression space 19 by the resulting force. Via the coupling 8, the low-pressure piston 4 presses the high-pressure piston 6 into the compression space 24. The volume of the compression space 24 is reduced and the fuel present in the compression space 24 is compressed, so that the pressure in the compression space 24 is increased beyond the system pressure to the desired injection pressure , The thus compressed and high pressure fuel flows from the compression chamber 24 through the drain 26 into the nozzle space, not shown.

Damit sich die Düsennadel aus ihrem Ventilsitz hebt und die nicht gezeigte(n) Einspritzöffnung(en) freigibt, wird ein zweites, nicht gezeigtes, Steuerventil so angesteuert, dass der Druck im Düsennadelsteuerraum abnimmt. Der auf die Düsenadel wirkende Druck im Düsenraum übersteigt dann den Schließdruck im Düsennadelsteuerraum. Die Düsennadel hebt vom Ventilsitz ab und Kraftstoff wird mit dem durch den Hochdruckkolben 6 über den Systemdruck hinaus verstärkten Einspritzdruck in den Brennraum der Verbrennungskraftmaschine eingespritzt.In order for the nozzle needle to lift out of its valve seat and release the injection opening (s) (not shown), a second control valve, not shown, is activated in such a way that the pressure in the nozzle needle control chamber decreases. The pressure acting on the nozzle needle pressure in the nozzle chamber then exceeds the closing pressure in the nozzle needle control chamber. The nozzle needle lifts off the valve seat and fuel is injected into the combustion chamber of the internal combustion engine with the injection pressure boosted by the high-pressure piston 6 beyond the system pressure.

Zum Beenden des Einspritzvorganges wird das zweite Steuerventil so geschaltet, dass der Druck im Düsennadelsteuerraum auf den Einspritzdruck ansteigt und die Düsennadel zurück in den Ventilsitz gedrückt wird, in dem sie die Einspritzöffnung(en) verschließt.To end the injection process, the second control valve is switched so that the pressure in the nozzle needle control chamber increases to the injection pressure and the nozzle needle is pushed back into the valve seat, in which it closes the injection opening (s).

Im nächsten Schritt wird das Steuerventil 28 so geschaltet, dass es die Verbindung vom Arbeitsraum 12 über die Arbeitsraumleitung 30 und die Differenzdruckraumleitung 16 in den Differenzdruckraum 14 freigibt. Unter Systemdruck stehender Kraftstoff strömt aus dem Arbeitsraum 12 in den Differenzdruckraum 14. Im Differenzdruckraum 14 baut sich wieder Systemdruck auf und drückt den Niederdruckkolben 4 zurück in seine Ausgangsposition.In the next step, the control valve 28 is switched so that it releases the connection from the working space 12 via the working space line 30 and the differential pressure space line 16 into the differential pressure space 14. Fuel under system pressure flows out of the working chamber 12 into the differential pressure chamber 14. In the differential pressure chamber 14 system pressure builds up again and pushes the low-pressure piston 4 back into its starting position.

Unterstützt von der Kolbenfeder 18 bewegt sich auch der Hochdruckkolben 4 aus dem Kompressionsraum 24 in Richtung auf den Arbeitsraum 12. Das Volumen des Kompressionsraums 24 vergrößert sich und der Druck im Kompressionsraum 24 nimmt ab. Sobald der Druck im Kompressionsraum 24 unter den Systemdruck gefallen ist, öffnet sich das Rückschlagventil 22 und Kraftstoff strömt aus dem Arbeitsraum 12 durch den Kraftstoffkanal 20 in den Kompressionsraum 24. Sobald der Hochdruckkolben 4 seine Ausgangsposition erreicht hat, in der das Volumen im Kompressionsraum 24 das Maximum erreicht hat, kann ein weiterer Einspritzvorgang gestartet werden.Supported by the piston spring 18 and the high pressure piston 4 moves from the compression chamber 24 in the direction of the working space 12. The volume of the compression chamber 24 increases and the pressure in the compression chamber 24 decreases. As soon as the pressure in the compression chamber 24 has fallen below the system pressure, the check valve 22 opens and fuel flows out of the working chamber 12 through the fuel passage 20 into the compression chamber 24. Once the high-pressure piston 4 has reached its starting position, in which the volume in the compression chamber 24 has reached the maximum, a further injection process can be started.

Figur 2 zeigt eine perspektivische Ansicht eines Ausschnitts aus einem erfindungsgemäßen Kraftstoffinjektor 2. In der Figur 2 ist nur der erste Injektorkörper 32 mit dem darin angeordneten zweiteiligen Druckverstärkerkolben 4, 6 gezeigt. Der zweite Injektorkörper 34, die Spannmutter 36, die Kolbenfeder 18 und das Steuerventil 28 sind aus Gründen der besseren Übersichtlichkeit nicht gezeigt. FIG. 2 shows a perspective view of a section of a fuel injector 2 according to the invention in the FIG. 2 only the first injector body 32 with the two-part pressure booster piston 4, 6 arranged therein is shown. The second injector body 34, the clamping nut 36, the piston spring 18 and the control valve 28 are not shown for reasons of clarity.

Die in Figur 2 gezeigten Bauelemente sind mit den gleichen Bezugszeichen wie in der Figur 1 bezeichnet. Der einfache Aufbau eines erfindungsgemäßen Druckverstärkerkolbens 4, 6 ist in der Figur 2 besonders gut erkennbar. Die Differenzdruckraumleitung 19 ist in dem in der Figur 2 nicht gezeigten Teil des ersten Injektorkörpers 32 ausgebildet und daher in der Figur 2 nicht sichtbar.In the FIG. 2 shown components are denoted by the same reference numerals as in the FIG. 1 designated. The simple structure of a pressure booster piston 4, 6 according to the invention is in the FIG. 2 particularly recognizable. The differential pressure space line 19 is in the in the FIG. 2 Not shown part of the first injector body 32 is formed and therefore in the FIG. 2 not visible.

Claims (8)

  1. Fuel injector (2), having
    a low-pressure piston (4) and a high-pressure piston (6),
    wherein the high-pressure piston (6) has a smaller cross section than the low-pressure piston (4); wherein, in the low-pressure piston (4), there is formed a bore which runs parallel to the longitudinal direction of the low-pressure piston (4) ;
    wherein a region of the high-pressure piston (6) is arranged in the bore;
    and wherein, in the high-pressure piston (6), there is formed a duct (20) which runs in the longitudinal direction of the high-pressure piston (6);
    characterized in that a check valve (22) is formed in the duct (20) which runs in the longitudinal direction of the high-pressure piston (6).
  2. Fuel injector (2) according to Claim 1, wherein the two pistons (4, 6) are arranged coaxially with respect to one another.
  3. Fuel injector (2) according to Claim 2, wherein a mechanical coupling (8) is formed between the high-pressure piston (6) and the low-pressure piston (4), and the coupling (8) is configured for transmitting forces oriented parallel to the common longitudinal axis of the pistons (4, 6).
  4. Fuel injector (2) according to Claim 3, wherein the coupling (8) is in the form of a hydraulic seal.
  5. Fuel injector (2) according to one of the preceding claims, wherein at least one of the pistons (4, 6) is of substantially cylindrical form.
  6. Fuel injector (2) according to one of the preceding claims, wherein the region of the high-pressure piston (6) is arranged with a radial clearance in the bore of the low-pressure piston (4).
  7. Fuel injector (2) according to Claim 6, wherein the clearance between the high-pressure piston (6) and the low-pressure piston (4) is configured such that the two pistons do not influence one another in the event of a movement in a radial direction.
  8. Fuel injector (2) according to Claim 6 or 7, wherein the clearance between the high-pressure piston (6) and the low-pressure piston (4) amounts to between 10 and 20 µm, and is preferably 15 µm.
EP10158114.8A 2009-05-29 2010-03-29 Fuel injector with pressure intensifier piston Not-in-force EP2256332B1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE200910026567 DE102009026567A1 (en) 2009-05-29 2009-05-29 Fuel injector with pressure intensifier piston

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EP2256332A2 EP2256332A2 (en) 2010-12-01
EP2256332A3 EP2256332A3 (en) 2013-03-20
EP2256332B1 true EP2256332B1 (en) 2016-08-17

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Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102010000828A1 (en) 2010-01-12 2011-07-14 Robert Bosch GmbH, 70469 Pressure boosting device for a fuel injection system and fuel injection system
US20240141856A1 (en) * 2022-11-02 2024-05-02 Ron Kukler High-pressure fuel injection system

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19954288A1 (en) * 1999-11-11 2001-05-17 Bosch Gmbh Robert Fuel injection valve for fitting to internal combustion engines has an injection valve element to control injection openings, a control valve to affect movement in injection valve elements and a valve element for regulating pressure
DE10123911A1 (en) * 2001-05-17 2002-11-28 Bosch Gmbh Robert Fuel injection device for internal combustion engine has transfer piston separating chamber connected to source from high pressure and return chambers
DE10314011A1 (en) * 2003-03-28 2004-10-07 Robert Bosch Gmbh Fuel injection valve for automobile IC engine, has valve control space of jet module coupled to valve space and feed channel for establishing pressure for closure of valve needle
DE102004053421A1 (en) 2004-11-05 2006-05-11 Robert Bosch Gmbh Fuel injector
JP4459183B2 (en) * 2006-03-16 2010-04-28 株式会社デンソー Injector
DE102007002760A1 (en) 2007-01-18 2008-07-24 Robert Bosch Gmbh Fuel injector with integrated pressure booster

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EP2256332A3 (en) 2013-03-20
EP2256332A2 (en) 2010-12-01

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