EP2354527B1 - Fuel injector - Google Patents

Fuel injector Download PDF

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Publication number
EP2354527B1
EP2354527B1 EP11150096.3A EP11150096A EP2354527B1 EP 2354527 B1 EP2354527 B1 EP 2354527B1 EP 11150096 A EP11150096 A EP 11150096A EP 2354527 B1 EP2354527 B1 EP 2354527B1
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EP
European Patent Office
Prior art keywords
valve
throttle
bore
space
control
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Not-in-force
Application number
EP11150096.3A
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German (de)
French (fr)
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EP2354527A2 (en
EP2354527A3 (en
Inventor
Holger Rapp
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Robert Bosch GmbH
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Robert Bosch GmbH
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Publication of EP2354527A2 publication Critical patent/EP2354527A2/en
Publication of EP2354527A3 publication Critical patent/EP2354527A3/en
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Publication of EP2354527B1 publication Critical patent/EP2354527B1/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • 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
    • F02M63/0045—Three-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
    • F02M47/00—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
    • F02M47/02—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure of accumulator-injector type, i.e. having fuel pressure of accumulator tending to open, and fuel pressure in other chamber tending to close, injection valves and having means for periodically releasing that closing pressure
    • F02M47/027—Electrically actuated valves draining the chamber to release the closing pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/28—Details of throttles in fuel-injection apparatus
    • 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 for a fuel injection system, in particular a common rail injection system, for injecting fuel into the combustion chamber of an internal combustion engine having the features of the preamble of claim 1.
  • the valve body is also accommodated in a valve chamber, which communicates with a control chamber via a first, serving as a drain hole in conjunction with a control chamber and a second, designated as a bypass bore in communication with an inlet channel.
  • fuel can flow into the control chamber via the bypass and the drainage channel in a first closed position of the valve body, so that a rapid closing of the nozzle needle is effected.
  • valve member of the control valve is in this case guided in a sleeve which rests sealingly on a throttle plate separating the valve chamber from the control chamber.
  • the sleeve defines between the valve member and the throttle plate a low pressure space, which leads to a reduction of the hydraulic closing force on the valve member and thus to a pressure relief of the valve member.
  • the required drive voltages or reduced currents is required.
  • the sleeve has a certain amount of space, so that the valve chamber must have a larger volume.
  • the increased valve chamber volume leads to a delayed pressure build-up both in the valve chamber and in the control chamber, which communicates with the valve chamber via at least one bore formed in the throttle plate.
  • the bore is to be guided in such a way that its mouth region lies outside the sleeve which bears sealingly against the throttle plate.
  • the sealing sleeve may be provided in the contact area with a reduced diameter and / or the valve space with a radial expansion in the mouth area of the bore, wherein a further increase in the valve space volume is unavoidable.
  • a throttle formed in the bore is often arranged in the region of the underside of the throttle plate, that is to say in the vicinity of the control chamber, the valve chamber volume is further increased by the outflow bore adjoining the throttle.
  • Object of the present invention is to develop a fuel injector of the type described above such that the valve chamber volume, especially in the arrangement of the valve member pressure-relieving sealing sleeve is kept as small as possible.
  • the formation of at least one arranged in the throttle plate bore or throttle should be simplified.
  • the proposed fuel injector has a nozzle needle in a hub movable guided nozzle needle for closing and releasing at least one formed in the nozzle body injection port and a control valve for indirect control of the nozzle needle by a valve needle in the closing direction acting control pressure is changed in a control room by opening or closing the control valve ,
  • the control valve in this case comprises a formed in a valve plate valve space which is bounded by a throttle plate which is arranged between the nozzle body and the valve plate and in which at least one bore for connecting the valve chamber with the control chamber and / or a high-pressure channel is formed.
  • the invention opens the at least one bore via an axial gap formed between the valve plate and the throttle plate in the valve chamber and has in the mouth region a reduced diameter d to form a throttle whose throttle effect on the height h of the axial gap can be influenced.
  • the throttle point is therefore displaced in the mouth region, so that the bore can be designed such that it has a constant diameter as far as possible.
  • the smallest quantity capability of the fuel injector and also its wear behavior in the area of the valve seat is improved. Because of the smaller valve space volume, the pressure in the valve chamber during the closing of the control valve increases rapidly, so that the remaining pressure stroke and the slippage of the valve in the seat after the impact decrease.
  • the production of the throttle is further simplified. This is now formed in the mouth region of the bore and thus at an easily accessible location on the top of the throttle plate. In addition, an outlet bore adjoining the throttle and / or a diffuser are eliminated. Furthermore, it is possible to dispense with a rounding of the bore in the region of the throttle, so that a further complicated production step is eliminated.
  • the throttling takes place in the mouth region of the bore and can be influenced by the height h of the axial gap between the valve plate and the throttle plate. Because of the throttle effect determining cross section corresponds to the lateral surface of an imaginary cylinder, which arises when the diameter d of the formed in the throttle plate outflow surface is projected onto the opposite surface of the valve plate. The height h of the axial gap corresponds to the height of the cylinder. The desired throttle effect can thus be achieved by establishing the parameters d and h during manufacture.
  • the height h of the axial gap is also chosen to be as small as possible in order to keep the valve space volume small.
  • the height h of the axial gap is preferably ⁇ 500 ⁇ m, preferably ⁇ 100 ⁇ m, more preferably ⁇ 50 ⁇ m.
  • the axial gap between the valve plate and the throttle plate is preferably formed by a primarily radially extending groove in the valve plate. Alternatively or additionally, however, a corresponding recess may also be provided in the throttle plate.
  • formed in the throttle plate bore connects the valve chamber of the control valve with the high-pressure passage and formed in the mouth region of the bore choke serves as a filler.
  • the height h of the axial gap is selected such that the fuel flowing out through the bore experiences a counter-pressure, that is to say a pressure counteracting the flow pressure, which reduces the entry of gas bubbles into the valve chamber when the valve is open.
  • the height h of the axial gap is chosen to be less than the height of a radial expansion of the valve space serving as a spout, which is usually about 1 mm.
  • the further bore serving as a drainage channel comprises an outlet throttle, which can be formed in a conventional manner by reducing the flow cross section of the bore in the region of the underside of the throttle plate, that is to say in the vicinity of the control chamber. At the throttle point is then followed by a long, the valve space volume magnifying discharge hole.
  • the bore formed in the throttle plate connects the valve space to the control chamber and the throttle formed in the mouth region of the bore serves as an outlet throttle.
  • the advantages described above in connection with the bore having the filling throttle now apply correspondingly to the bore serving as a drainage channel. This means that the hole is easy to produce due to its largely constant diameter.
  • the displacement of the throttle point in the mouth area also simplifies the formation of the throttle, which is now arranged at the top of the throttle plate and makes a long outflow bore and / or a diffuser dispensable.
  • a further, correspondingly formed bore or throttle for connecting the valve chamber to the high-pressure passage can be provided so that further a fast filling of the valve space volume and thus a rapid pressure build-up in the control chamber is ensured.
  • At least one bore provided in the throttle plate is formed to be hydroerosive rounded at least in a partial region. This measure proves to be particularly advantageous if the flow of a throttle scatters too much.
  • the rounding is preferably carried out in the assembled state with associated valve plate.
  • control valve comprises a cooperating with a valve seat liftable valve member whose valve seat opposite end is guided in a sealingly adjacent to the throttle plate and a low pressure space limiting sleeve, so that the valve member is relieved of pressure in contact with the valve seat. Because by the leadership of the valve member in such a sealing sleeve, the hydraulic closing force is reduced to the valve member. This in turn leads to a reduction of the switching forces and concomitantly to a reduction of the required drive voltages or currents.
  • sealing sleeve usually requires an enlarged valve chamber volume
  • advantages of the invention, in particular in a control valve with such a sealing sleeve come into play. Because the interaction of the throttle plate formed bore with the formed in the valve plate axial gap is able to compensate for at least a portion of the valve space enlargement.
  • the limited by the sleeve low pressure space is connected via a bore to a return.
  • the the low pressure chamber with a return connecting hole is at least partially also formed in the throttle plate.
  • a piezoelectric actuator is provided for actuating the control valve.
  • Fig. 1 is a section of an already known fuel injector refer.
  • the detail shows the fuel injector in the region of a throttle plate 7 including adjacent components.
  • the latter include a nozzle body 1, which is attached in the drawing from below to the throttle plate 7 and the recording of a liftably guided nozzle needle 2 for releasing or closing at least one nozzle opening formed in the injection orifice 1, and a valve plate 5, in the drawing from above is attached to the throttle plate 7 and the recording of a control valve 3 for indirect control of the nozzle needle 2 is used.
  • the control valve 3 has a valve space 6 which can be connected to a return 20 and which is furthermore connected to a control chamber 4 via a bore 12 designed as a drainage channel.
  • Control chamber 4 is in turn via an inlet channel 21 in hydraulic communication with a high pressure passage 9, so that a filling of the control chamber 4 is ensured with fuel with the control valve 3 closed.
  • the fuel flowing into the control chamber 4 via the inlet channel 21 causes an increase in the control pressure existing there, which acts on the nozzle needle 2 in the closing direction.
  • the nozzle needle 2 completes a closing movement or is held in its closed position. If the control valve 3 is opened, wherein a compound of the valve chamber 6 is prepared for return 20 and a Abêtmenge the return 20 is supplied, it comes in the valve chamber 6 and the control chamber 4 to a pressure drop, which allows an opening stroke of the nozzle needle 2.
  • the actuation of the control valve 3 takes place here by using a piezoelectric actuator, which lifts a valve member 16 of the control valve 3 from its valve seat 15 during energization and thus establishes the connection of the valve chamber 6 to the return line 20.
  • the valve member 16 is presently guided in a sleeve 18 which rests sealingly against the throttle plate 7 and a low-pressure chamber 17 radially limited. Through a bore 19 of the low-pressure chamber 17 is in communication with the return 20. Due to the fact that the valve seat facing away and absorbed in the sleeve 18 end of the valve member 16 is not high pressure, the valve member 16 is depressurized.
  • the actuation of the control valve therefore requires lower switching forces, that is, lower drive voltages or drive currents. This has an advantageous effect on the design of the piezoelectric actuator as an actuating means.
  • a further bore 8 is provided in the throttle plate, which the valve chamber. 6 connects directly to the high pressure channel 9.
  • the bores 8, 12 and 21 each have a reduced flow cross-section in the region of the underside of the throttle plate 7.
  • the reduced flow cross section is followed in each case by a long outlet bore, which opens into the valve chamber 6 in the region of a radial widening, that is to say a spout.
  • Both the long outflow holes, as well as the volume of the Schnaupen contribute to an undesirable increase in the volume of the valve chamber 6.
  • the disadvantage of an enlarged valve space volume due to the use of a sleeve 18 for pressure relief of the valve member 16 is compensated by the fact that the throttle 11 of the bore 8 has been moved into the mouth region of the bore 8. A long the valve chamber 6 enlarging discharge hole thus eliminated. Furthermore, the spout has been replaced by an axial gap 10 between the valve plate 5 and the throttle plate 7, over the height h of the throttle effect can be influenced. The axial gap 10 thus forms a part of the throttle 11.
  • the serving as a drain passage bore 12 is in the embodiment of Fig.
  • a throttle 14 which is formed in the lower region of the bore 12 and to which a long outflow bore connects.
  • a throttle 14 which is formed in the lower region of the bore 12 and to which a long outflow bore connects.
  • Alternatively, however, also serving as a drain passage bore 12 may be formed according to the bore 8 with a throttle 14 in the mouth region.
  • FIG. 3 Another alternative embodiment of serving as a drain passage bore 12 goes out of the in Fig. 3 illustrated embodiment of a fuel injector according to the invention.
  • the height h is selected such that a back pressure is applied to the outflowing fuel.
  • the back pressure should reduce the entry of gas bubbles in the valve chamber 6.
  • the axial gap 13 has a height h which is opposite to the height of the in Fig. 1 shown spout is significantly reduced, so that a reduction of the valve chamber volume is achieved.
  • the height h of the axial gap 13 is greater than the height h of the axial gap 10 chosen, since within the bore 12 is already formed a flow restrictor 14 for throttling the fuel flow.

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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

Die Erfindung betrifft einen Kraftstoffinjekor für ein Kraftstoffeinspritzsystem, insbesondere ein Common-Rail-Einspritzsystem, zum Einspritzen von Kraftstoff in den Brennraum einer Brennkraftmaschine mit den Merkmalen des Oberbegriffes des Anspruchs 1.The invention relates to a fuel injector for a fuel injection system, in particular a common rail injection system, for injecting fuel into the combustion chamber of an internal combustion engine having the features of the preamble of claim 1.

Stand der TechnikState of the art

Ein Kraftstoffinjektor der eingangs genannten Art geht beispielsweise aus der DE 10 2004 061 800 A1 hervor. Dieser weist zum Öffnen und Schließen einer in einem Düsenkörper hubbeweglich geführten Düsenadel ein Steuerventil mit einem Ventilkörper auf, der zumindest in einem Teilbereich geführt ist. Durch die Führung des Ventilköpers, beispielsweise mittels einer Hülse, ist eine verschleißarme Betätigung des Steuerventils gewährleistet. Der Ventilkörper ist zudem in einem Ventilraum aufgenommen, der über eine erste, als Ablaufkanal dienende Bohrung in Verbindung mit einem Steuerraum und über eine zweite, als Bypass bezeichnete Bohrung in Verbindung mit einem Zulaufkanal steht. Über den Bypass und den Ablaufkanal kann in einer ersten Schließstellung des Ventilkörpers zusätzlich Kraftstoff in den Steuerraum strömen, so dass ein schnelles Schließen der Düsennadel bewirkt wird.A fuel injector of the type mentioned, for example, from the DE 10 2004 061 800 A1 out. This has to open and close a liftable in a nozzle body guided nozzle needle on a control valve with a valve body which is guided at least in a partial area. By the leadership of Ventilköpers, for example by means of a sleeve, a low-wear operation of the control valve is ensured. The valve body is also accommodated in a valve chamber, which communicates with a control chamber via a first, serving as a drain hole in conjunction with a control chamber and a second, designated as a bypass bore in communication with an inlet channel. In addition, fuel can flow into the control chamber via the bypass and the drainage channel in a first closed position of the valve body, so that a rapid closing of the nozzle needle is effected.

Ein weiterer gattungsgemäßer Kraftstoffinjektor geht aus der Offenlegungsschrift DE 10 2008 001 330 A1 hervor. Das Ventilglied des Steuerventils ist hierbei in einer Hülse geführt, die dichtend an einer den Ventilraum vom Steuerraum trennenden Drosselplatte anliegt. Die Hülse begrenzt zwischen dem Ventilglied und der Drosselplatte einen Niederdruckraum, der zu einer Reduktion der hydraulischen Schließkraft am Ventilglied und damit zu einer Druckentlastung des Ventilglieds führt. Dadurch werden auch die benötigten Ansteuerspannungen bzw. ströme reduziert. Die Hülse besitzt jedoch einen gewissen Platzbedarf, so dass der Ventilraum ein größeres Volumen aufweisen muss. Das vergrößerte Ventilraumvolumen führt zu einem verzögerten Druckaufbau sowohl im Ventilraum, als auch im Steuerraum, der über wenigstens eine in der Drosselplatte ausgebildeten Bohrung in Verbindung mit dem Ventilraum steht. Ferner ist die Bohrung derart zu führen, dass ihr Mündungsbereich außerhalb der dichtend an der Drosselplatte anliegenden Hülse liegt. Hierzu kann die Dichthülse im Anlagebereich mit einem verringerten Durchmesser und/oder der Ventilraum mit einer radialen Aufweitung im Mündungsbreich der Bohrung ausgestattet sein, wobei eine weitere Vergrößerung des Ventilraumvolumens unvermeidlich ist. Da zudem eine in der Bohrung ausgebildete Drossel fertigungsbedingt oftmals im Bereich der Unterseite der Drosselplatte, das heißt in der Nähe des Steuerraums, angeordnet ist, wird das Ventilraumvolumen durch die sich an die Drossel anschließende Abströmbohrung weiter vergrößert.Another generic fuel injector is from the published patent application DE 10 2008 001 330 A1 out. The valve member of the control valve is in this case guided in a sleeve which rests sealingly on a throttle plate separating the valve chamber from the control chamber. The sleeve defines between the valve member and the throttle plate a low pressure space, which leads to a reduction of the hydraulic closing force on the valve member and thus to a pressure relief of the valve member. As a result, the required drive voltages or reduced currents. However, the sleeve has a certain amount of space, so that the valve chamber must have a larger volume. The increased valve chamber volume leads to a delayed pressure build-up both in the valve chamber and in the control chamber, which communicates with the valve chamber via at least one bore formed in the throttle plate. Furthermore, the bore is to be guided in such a way that its mouth region lies outside the sleeve which bears sealingly against the throttle plate. For this purpose, the sealing sleeve may be provided in the contact area with a reduced diameter and / or the valve space with a radial expansion in the mouth area of the bore, wherein a further increase in the valve space volume is unavoidable. Moreover, since a throttle formed in the bore is often arranged in the region of the underside of the throttle plate, that is to say in the vicinity of the control chamber, the valve chamber volume is further increased by the outflow bore adjoining the throttle.

Aus EP 0 976 924 A2 und EP 1 245 822 A2 sind darüber hinaus Kraftstoffeinspritzventile mit einem Servoventil bekannt, bei denen die Befüllung des Steuerraums über eine direkte Verbindung mit einem Hochdruckkanal geschieht.Out EP 0 976 924 A2 and EP 1 245 822 A2 In addition, fuel injection valves are known with a servo valve, in which the filling of the control chamber is done via a direct connection to a high-pressure channel.

Aufgabe der vorliegenden Erfindung ist es, einen Kraftstoffinjektor der vorstehend beschriebenen Art derart weiterzubilden, dass das Ventilraumvolumen, insbesondere bei Anordnung einer das Ventilglied druckentlastenden Dichthülse, möglichst klein gehalten wird. Zudem soll die Ausbildung wenigstens einer in der Drosselplatte angeordneten Bohrung bzw. Drossel vereinfacht werden.Object of the present invention is to develop a fuel injector of the type described above such that the valve chamber volume, especially in the arrangement of the valve member pressure-relieving sealing sleeve is kept as small as possible. In addition, the formation of at least one arranged in the throttle plate bore or throttle should be simplified.

Zur Lösung der Aufgabe wird ein Kraftstoffinjektor mit den Merkmalen des Anspruchs 1 vorgeschlagen. Bevorzugte Weiterbildungen der Erfindung werden in den Unteransprüchen angegeben.To solve the problem, a fuel injector with the features of claim 1 is proposed. Preferred developments of the invention are specified in the subclaims.

Offenbarung der ErfindungDisclosure of the invention

Der vorgeschlagene Kraftstoffinjektor weist eine in einem Düsenkörper hubbeweglich geführte Düsennadel zum Schließen und Freigeben wenigstens einer im Düsenkörper ausgebildeten Einspritzöffnung und ein Steuerventil zur indirekten Ansteuerung der Düsennadel auf, indem durch Öffnen oder Schließen des Steuerventils ein die Düsennadel in Schließrichtung beaufschlagender Steuerdruck in einem Steuerraum verändert wird. Das Steuerventil umfasst dabei einen in einer Ventilplatte ausgebildeten Ventilraum, der von einer Drosselplatte begrenzt wird, die zwischen dem Düsenkörper und der Ventilplatte angeordnet ist und in welcher wenigstens eine Bohrung zur Verbindung des Ventilraums mit dem Steuerraum und/oder einem Hochdruckkanal ausgebildet ist.The proposed fuel injector has a nozzle needle in a hub movable guided nozzle needle for closing and releasing at least one formed in the nozzle body injection port and a control valve for indirect control of the nozzle needle by a valve needle in the closing direction acting control pressure is changed in a control room by opening or closing the control valve , The control valve in this case comprises a formed in a valve plate valve space which is bounded by a throttle plate which is arranged between the nozzle body and the valve plate and in which at least one bore for connecting the valve chamber with the control chamber and / or a high-pressure channel is formed.

Erfindungsgemäß mündet die wenigstens eine Bohrung über einen zwischen der Ventilplatte und der Drosselplatte ausgebildeten Axialspalt in den Ventilraum und besitzt im Mündungsbereich einen reduzierten Durchmesser d zur Ausbildung einer Drossel, deren Drosselwirkung über die Höhe h des Axialspalts beeinflussbar ist. Die Drosselstelle ist demnach in den Mündungsbereich verlagert, so dass die Bohrung derart ausgebildet sein kann, dass sie weitestgehend einen konstanten Durchmesser besitzt. Dadurch wird zum Einen die Herstellung der Bohrung vereinfacht, zum Anderen kann eine im Bereich der Unterseite der Drosselplatte ausgebildete Drosselstelle und damit eine sich hieran anschließende lange Abströmbohrung entfallen. Durch den Wegfall der Abströmbohrung wird das Ventilraumvolumen verringert, was wiederum zu einem schnellen Druckaufbau und zu schnellen Schaltzeiten führt. Gleichzeitig wird die Kleinstmengenfähigkeit des Kraftstoffinjektors und ferner sein Verschleißverhalten im Bereich des Ventilsitzes verbessert. Denn aufgrund des kleineren Ventilraumvolumens steigt der Druck im Ventilraum während des Schließvorgangs des Steuerventils schnell an, so dass der verbleibende Druckhub und der Schlupf des Ventils im Sitz nach dem Einschlag sich verringern.According to the invention opens the at least one bore via an axial gap formed between the valve plate and the throttle plate in the valve chamber and has in the mouth region a reduced diameter d to form a throttle whose throttle effect on the height h of the axial gap can be influenced. The throttle point is therefore displaced in the mouth region, so that the bore can be designed such that it has a constant diameter as far as possible. As a result, on the one hand, the production of the bore is simplified, on the other hand, a throttling point formed in the region of the underside of the throttle plate and thus a long outflow bore following thereon can be dispensed with. The omission of the outflow bore reduces the valve volume, which in turn leads to a rapid pressure build-up and fast switching times. At the same time, the smallest quantity capability of the fuel injector and also its wear behavior in the area of the valve seat is improved. Because of the smaller valve space volume, the pressure in the valve chamber during the closing of the control valve increases rapidly, so that the remaining pressure stroke and the slippage of the valve in the seat after the impact decrease.

Neben der Herstellung der Bohrung wird ferner die Herstellung der Drossel vereinfacht. Diese ist nunmehr im Mündungsbereich der Bohrung und damit an leicht zugänglicher Stelle an der Oberseite der Drosselplatte ausgebildet. Zudem entfallen eine sich an die Drossel anschließende Abströmbohrung und/oder ein Diffusor. Des Weiteren kann auf eine Verrundung der Bohrung im Bereich der Drossel verzichtet werden, so dass ein weiterer aufwendiger Fertigungsschritt entfällt. Die Drosselung erfolgt im Mündungsbereich der Bohrung und kann über die Höhe h des Axialspalts zwischen der Ventilplatte und der Drosselplatte beeinflusst werden. Denn der die Drosselwirkung bestimmende Querschnitt entspricht der Mantelfläche eines gedachten Zylinders, der entsteht, wenn der Durchmesser d der in der Drosselplatte ausgebildeten Abströmfläche auf die gegenüberliegende Fläche der Ventilplatte projiziert wird. Die Höhe h des Axialspalts entspricht dabei der Höhe des Zylinders. Die gewünschte Drosselwirkung kann demnach durch Festlegung der Parameter d und h bei der Herstellung erreicht werden.In addition to the production of the bore, the production of the throttle is further simplified. This is now formed in the mouth region of the bore and thus at an easily accessible location on the top of the throttle plate. In addition, an outlet bore adjoining the throttle and / or a diffuser are eliminated. Furthermore, it is possible to dispense with a rounding of the bore in the region of the throttle, so that a further complicated production step is eliminated. The throttling takes place in the mouth region of the bore and can be influenced by the height h of the axial gap between the valve plate and the throttle plate. Because of the throttle effect determining cross section corresponds to the lateral surface of an imaginary cylinder, which arises when the diameter d of the formed in the throttle plate outflow surface is projected onto the opposite surface of the valve plate. The height h of the axial gap corresponds to the height of the cylinder. The desired throttle effect can thus be achieved by establishing the parameters d and h during manufacture.

Die Höhe h des Axialspalts ist zudem möglichst klein gewählt, um das Ventilraumvolumen klein zu halten. Bevorzugt beträgt die Höhe h des Axialspalts ≤ 500 µm, vorzugsweise ≤ 100 µm, weiterhin vorzugsweise ≤ 50 µm. Der Axialspalt zwischen der Ventilplatte und der Drosselplatte wird bevorzugt durch eine vorrangig radial verlaufende Nut in der Ventilplatte gebildet. Alternativ oder ergänzend kann aber auch eine entsprechende Ausnehmung in der Drosselplatte vorgesehen sein.The height h of the axial gap is also chosen to be as small as possible in order to keep the valve space volume small. The height h of the axial gap is preferably ≦ 500 μm, preferably ≦ 100 μm, more preferably ≦ 50 μm. The axial gap between the valve plate and the throttle plate is preferably formed by a primarily radially extending groove in the valve plate. Alternatively or additionally, however, a corresponding recess may also be provided in the throttle plate.

Erfindungsgemäß verbindet die in der Drosselplatte ausgebildete Bohrung den Ventilraum des Steuerventils mit dem Hochdruckkanal und die im Mündungsbereich der Bohrung ausgebildete Drossel dient als Fülldrossel. Durch diese Maßnahmen ist ein schnelles Befüllen des Ventilraumvolumens und damit ein schneller Druckaufbau im Steuerraum sichergestellt, der wiederum ein schnelles Düsennadelschließen gewährleistet. Denn der Ventilraum und der Steuerraum sind über wenigstens eine weitere in der Drosselplatte ausgebildete und als Ablaufkanal dienende Bohrung hydraulisch verbunden.According to the invention formed in the throttle plate bore connects the valve chamber of the control valve with the high-pressure passage and formed in the mouth region of the bore choke serves as a filler. By these measures, a fast filling of the valve space volume and thus a rapid pressure build-up in the control room is ensured, which in turn ensures a fast nozzle needle closing. Because the valve chamber and the control chamber are hydraulically connected via at least one further formed in the throttle plate and serving as a drainage hole.

Die als Ablaufkanal dienende weitere Bohrung, die den Ventilraum mit dem Steuerraum verbindet, mündet vorzugsweise über einen weiteren zwischen der Ventilplatte und der Drosselplatte ausgebildeten Axialspalt in den Ventilraum des Steuerventils. Dabei ist die Höhe h des Axialspalts derart gewählt, dass der über die Bohrung abströmende Kraftstoff einen Gegendruck, das heißt einen dem Strömungsdruck entgegen wirkenden Druck, erfährt, der den Eintrag von Gasblasen in den Ventilraum bei geöffnetem Ventil verrringert. Um diesen Gegendruck zu erzeugen, ist die Höhe h des Axialspalts geringer als die Höhe einer als Schnaupe dienenden radialen Aufweitung des Ventilraums gewählt, die üblicherweise bei etwa 1 mm liegt.Serving as a drain passage further bore which connects the valve chamber to the control chamber, preferably opens via a further formed between the valve plate and the throttle plate axial gap in the valve chamber of the control valve. In this case, the height h of the axial gap is selected such that the fuel flowing out through the bore experiences a counter-pressure, that is to say a pressure counteracting the flow pressure, which reduces the entry of gas bubbles into the valve chamber when the valve is open. In order to produce this back pressure, the height h of the axial gap is chosen to be less than the height of a radial expansion of the valve space serving as a spout, which is usually about 1 mm.

Die als Ablaufkanal dienende weitere Bohrung umfasst eine Ablaufdrossel, die in herkömmlicher Weise durch eine Verringerung des Durchströmungsquerschnitts der Bohrung im Bereich der Unterseite der Drosselplatte, das heißt in der Nähe zum Steuerraum, ausgebildet sein kann. An die Drosselstelle schließt sich dann eine lange, das Ventilraumvolumen vergrößernde Abströmbohrung an.The further bore serving as a drainage channel comprises an outlet throttle, which can be formed in a conventional manner by reducing the flow cross section of the bore in the region of the underside of the throttle plate, that is to say in the vicinity of the control chamber. At the throttle point is then followed by a long, the valve space volume magnifying discharge hole.

Um eine Vergrößerung des Ventilraumvolumens zu vermeiden, ist gemäß einer alternativen Ausführungsform bzw. einer Weiterbildung der Erfindung vorgesehen, dass die in der Drosselplatte ausgebildete Bohrung den Ventilraum mit dem Steuerraum verbindet und die im Mündungsbereich der Bohrung ausgebildete Drossel als Ablaufdrossel dient. Die vorstehend in Zusammenhang mit der die Fülldrossel aufweisenden Bohrung beschriebenen Vorteile gelten nunmehr für die als Ablaufkanal dienende Bohrung entsprechend. Das heißt, dass die Bohrung aufgrund ihres weitestgehend konstanten Durchmessers einfach herstellbar ist. Die Verlagerung der Drosselstelle in den Mündungsbereich vereinfacht zudem die Ausbildung der Drossel, die nunmehr an der Oberseite der Drosselplatte angeordnet ist und eine lange Abströmbohrung und/oder einen Diffusor entbehrlich macht. Zusätzlich zum Abaufkanal kann eine weitere, entsprechend ausgebildete Bohrung bzw. Drossel zur Verbindung des Ventilraums mit dem Hochdruckkanal vorgesehen sein, so dass ferner ein schnelles Befüllen des Ventilraumvolumens und damit einer schneller Druckaufbau im Steuerraum gewährleistet ist.In order to avoid an enlargement of the valve space volume, according to an alternative embodiment or a development of the invention, it is provided that the bore formed in the throttle plate connects the valve space to the control chamber and the throttle formed in the mouth region of the bore serves as an outlet throttle. The advantages described above in connection with the bore having the filling throttle now apply correspondingly to the bore serving as a drainage channel. This means that the hole is easy to produce due to its largely constant diameter. The displacement of the throttle point in the mouth area also simplifies the formation of the throttle, which is now arranged at the top of the throttle plate and makes a long outflow bore and / or a diffuser dispensable. In addition to the drainage channel, a further, correspondingly formed bore or throttle for connecting the valve chamber to the high-pressure passage can be provided so that further a fast filling of the valve space volume and thus a rapid pressure build-up in the control chamber is ensured.

Ergänzend kann vorgesehen sein, dass wenigstens eine in der Drosselplatte vorgesehene Bohrung zumindest in einem Teilbereich hydroerosiv verrundet ausgebildet ist. Diese Maßnahme erweist sich insbesondere dann als vorteilhaft, wenn der Durchfluss einer Drossel zu stark streut. Die Verrundung erfolgt vorzugsweise im zusammengefügten Zustand mit zugehöriger Ventilplatte.In addition, it may be provided that at least one bore provided in the throttle plate is formed to be hydroerosive rounded at least in a partial region. This measure proves to be particularly advantageous if the flow of a throttle scatters too much. The rounding is preferably carried out in the assembled state with associated valve plate.

Gemäß einer bevorzugten Ausführungsform umfasst das Steuerventil ein mit einem Ventilsitz zusammenwirkendes hubbewegliches Ventilglied, dessen ventilsitzabgewandtes Ende in einer an der Drosselplatte dichtend anliegenden und einen Niederdruckraum begrenzenden Hülse geführt ist, so dass das Ventilglied in Anlage am Ventilsitz druckentlastet ist. Denn durch die Führung des Ventilgliedes in einer solchen Dichthülse wird die hydraulische Schließkraft auf das Ventilglied reduziert. Dies wiederum führt zu einer Verringerung der Schaltkräfte und damit einhergehend zu einer Verringerung der benötigten Ansteuerspannungen bzw. -ströme.According to a preferred embodiment, the control valve comprises a cooperating with a valve seat liftable valve member whose valve seat opposite end is guided in a sealingly adjacent to the throttle plate and a low pressure space limiting sleeve, so that the valve member is relieved of pressure in contact with the valve seat. Because by the leadership of the valve member in such a sealing sleeve, the hydraulic closing force is reduced to the valve member. This in turn leads to a reduction of the switching forces and concomitantly to a reduction of the required drive voltages or currents.

Da die Dichthülse in der Regel ein vergrößertes Ventilraumvolumen erfordert, kommen die Vorteile der Erfindung insbesondere bei einem Steuerventil mit einer solchen Dichthülse zum Tragen. Denn das Zusammenwirken der in der Drosselplatte ausgebildeten Bohrung mit dem in der Ventilplatte ausgebildeten Axialspalt vermag zumindest einen Teil der Ventilraumvergrößerung zu kompensieren.Since the sealing sleeve usually requires an enlarged valve chamber volume, the advantages of the invention, in particular in a control valve with such a sealing sleeve come into play. Because the interaction of the throttle plate formed bore with the formed in the valve plate axial gap is able to compensate for at least a portion of the valve space enlargement.

Vorzugsweise ist der von der Hülse begrenzte Niederdruckraum über eine Bohrung an einen Rücklauf angeschlossen. Die den Niederdruckraum mit einem Rücklauf verbindende Bohrung ist zumindest teilweise ebenfalls in der Drosselplatte ausgebildet.Preferably, the limited by the sleeve low pressure space is connected via a bore to a return. The the low pressure chamber with a return connecting hole is at least partially also formed in the throttle plate.

Weiterhin vorzugsweise ist zur Betätigung des Steuerventils ein Piezoaktor vorgesehen.Further preferably, a piezoelectric actuator is provided for actuating the control valve.

Bevorzugte Ausführungsformen der Erfindung werden nachfolgend anhand der Zeichnungen näher erläutert. Diese zeigen:

  • Fig. 1 einen Längsschnitt durch einen aus dem Stand der Technik bekannten Kraftstoffinjektor im Bereich der Drosselplatte,
  • Fig. 2 einen Längsschnitt durch einen ersten erfindungsgemäßen Kraftstoffinjektor im Bereich der Drosselplatte und
  • Fig. 3 einen Längsschnitt durch einen zweiten erfindungsgemäßen Kraftstoffinjektor im Bereich der Drosselplatte.
Preferred embodiments of the invention are explained below with reference to the drawings. These show:
  • Fig. 1 a longitudinal section through a known from the prior art fuel injector in the throttle plate,
  • Fig. 2 a longitudinal section through a first fuel injector according to the invention in the region of the throttle plate and
  • Fig. 3 a longitudinal section through a second fuel injector according to the invention in the region of the throttle plate.

Ausführliche Beschreibung der ZeichnungenDetailed description of the drawings

Der Fig. 1 ist ein Ausschnitt eines bereits bekannten Kraftstoffinjektors zu entnehmen. Der Ausschnitt zeigt den Kraftstoffinjektor im Bereich einer Drosselplatte 7 einschließlich angrenzender Bauteile. Letztere umfassen einen Düsenkörper 1, der in der Zeichnung von unten an die Drosselplatte 7 angesetzt ist und der Aufnahme einer hubbeweglich geführten Düsennadel 2 zum Freigeben oder Verschließen wenigstens einer im Düsenkörper 1 ausgebildeten Einspritzöffnung dient, sowie eine Ventilplatte 5, die in der Zeichnung von oben an die Drosselplatte 7 angesetzt ist und der Aufnahme eines Steuerventils 3 zur indirekten Ansteuerung der Düsennadel 2 dient. Das Steuerventil 3 weist hierzu einen mit einem Rücklauf 20 verbindbaren Ventilraum 6 auf, der ferner über eine als Ablaufkanal ausgebildete Bohrung 12 mit einem Steuerraum 4 in Verbindung steht. Der Steuerraum 4 steht wiederum über einen Zulaufkanal 21 in hydraulischer Verbindung mit einem Hochdruckkanal 9, so dass eine Befüllung des Steuerraums 4 mit Kraftstoff bei geschlossenem Steuerventil 3 gewährleistet ist. Der über den Zulaufkanal 21 in den Steuerraum 4 einströmende Kraftstoff bewirkt einen Anstieg des dort vorhandenen Steuerdrucks, der die Düsennadel 2 in Schließrichtung beaufschlagt. Die Düsennadel 2 vollzieht eine Schließbewegung bzw. wird in ihrer Schließstellung gehalten. Wird das Steuerventil 3 geöffnet, wobei eine Verbindung des Ventilraums 6 zum Rücklauf 20 hergestellt und eine Absteuermenge dem Rücklauf 20 zugeführt wird, kommt es im Ventilraum 6 und im Steuerraum 4 zu einem Druckabfall, der einen Öffnungshub der Düsennadel 2 ermöglicht. Die Betätigung des Steuerventils 3 erfolgt vorliegend durch Einsatz eines Piezoaktors, der bei Bestromung ein Ventilglied 16 des Steuerventils 3 aus seinem Ventilsitz 15 hebt und damit die Verbindung des Ventilraums 6 zum Rücklauf 20 herstellt. Das Ventilglied 16 ist vorliegend in einer Hülse 18 geführt, die dichtend an der Drosselplatte 7 anliegt und einen Niederdruckraum 17 radial begrenzt. Über eine Bohrung 19 steht der Niederdruckraum 17 in Verbindung mit dem Rücklauf 20. Dadurch, dass das ventilsitzabgewandte und in der Hülse 18 aufgenommene Ende des Ventilgliedes 16 nicht hochdruckbeaufschlagt ist, wird das Ventilglied 16 druckentlastet. Die Betätigung des Steuerventils erfordert demnach geringere Schaltkräfte, das heißt geringere Ansteuerspannungen bzw. Ansteuerströme. Dies wirkt sich vorteilhaft auf die Auslegung des Piezoaktors als Betätigungsmittel aus.Of the Fig. 1 is a section of an already known fuel injector refer. The detail shows the fuel injector in the region of a throttle plate 7 including adjacent components. The latter include a nozzle body 1, which is attached in the drawing from below to the throttle plate 7 and the recording of a liftably guided nozzle needle 2 for releasing or closing at least one nozzle opening formed in the injection orifice 1, and a valve plate 5, in the drawing from above is attached to the throttle plate 7 and the recording of a control valve 3 for indirect control of the nozzle needle 2 is used. For this purpose, the control valve 3 has a valve space 6 which can be connected to a return 20 and which is furthermore connected to a control chamber 4 via a bore 12 designed as a drainage channel. Of the Control chamber 4 is in turn via an inlet channel 21 in hydraulic communication with a high pressure passage 9, so that a filling of the control chamber 4 is ensured with fuel with the control valve 3 closed. The fuel flowing into the control chamber 4 via the inlet channel 21 causes an increase in the control pressure existing there, which acts on the nozzle needle 2 in the closing direction. The nozzle needle 2 completes a closing movement or is held in its closed position. If the control valve 3 is opened, wherein a compound of the valve chamber 6 is prepared for return 20 and a Absteuermenge the return 20 is supplied, it comes in the valve chamber 6 and the control chamber 4 to a pressure drop, which allows an opening stroke of the nozzle needle 2. The actuation of the control valve 3 takes place here by using a piezoelectric actuator, which lifts a valve member 16 of the control valve 3 from its valve seat 15 during energization and thus establishes the connection of the valve chamber 6 to the return line 20. The valve member 16 is presently guided in a sleeve 18 which rests sealingly against the throttle plate 7 and a low-pressure chamber 17 radially limited. Through a bore 19 of the low-pressure chamber 17 is in communication with the return 20. Due to the fact that the valve seat facing away and absorbed in the sleeve 18 end of the valve member 16 is not high pressure, the valve member 16 is depressurized. The actuation of the control valve therefore requires lower switching forces, that is, lower drive voltages or drive currents. This has an advantageous effect on the design of the piezoelectric actuator as an actuating means.

Ein Nachteil der Anordnung einer Hülse 18 in dem Ventilraum 6 besteht jedoch darin, dass die Hülse 18 einen größeres Ventilraumvolumen erfordert. Um dennoch eine schnelle Befüllung und damit einen schnellen Druckanstieg im Ventilraum 6 und im mit dem Ventilraum 6 verbundenen Steuerraum 4 zu ermöglichen, ist neben der als Ablaufkanal dienenden Bohrung 12 und dem Zulaufkanal 21 eine weitere Bohrung 8 in der Drosselplatte vorgesehen, die den Ventilraum 6 direkt mit dem Hochdruckkanal 9 verbindet. Bei geschlossenem Steuerventil 3 strömt somit nicht nur Kraftstoff über den Zulaufkanal 21 in Steuerraum 4, sondern auch über die Bohrungen 8 und 12, wobei die als Ablaufkanal dienende Bohrung 12 in umgekehrter Richtung durchströmt wird.A disadvantage of the arrangement of a sleeve 18 in the valve chamber 6, however, is that the sleeve 18 requires a larger valve chamber volume. In order to still allow fast filling and thus a rapid increase in pressure in the valve chamber 6 and connected to the valve chamber 6 control chamber 4, in addition to serving as a drain passage bore 12 and the inlet channel 21, a further bore 8 is provided in the throttle plate, which the valve chamber. 6 connects directly to the high pressure channel 9. When the control valve 3 is closed, therefore, not only does fuel flow via the inlet channel 21 into the control chamber 4, but also via the bores 8 and 12, whereby the bore 12 serving as a drain channel is flowed through in the reverse direction.

Üblicherweise weist jede als Ablauf- und/oder als Zulaufkanal dienende Bohrung 8, 12, 21 eine Drossel 11, 14, 22 zur Drosselung des Kraftstoffstroms auf. Zur Ausbildung der Drosseln 11, 14, 22 weisen die Bohrungen 8, 12 und 21 jeweils einen verringerten Durchströmungsquerschnitt im Bereich der Unterseite der Drosselplatte 7 auf. An den verringerten Durchströmungsquerschnitt schließt sich jeweils eine lange Abströmbohrung an, die in den Ventilraum 6 im Bereich einer radialen Aufweitung, das heißt einer Schnaupe, mündet. Sowohl die langen Abströmbohrungen, als auch das Volumen der Schnaupen tragen zu einer unerwünschten Vergrößerung des Volumens des Ventilraums 6 bei.Usually, each serving as a drain and / or as an inlet channel bore 8, 12, 21, a throttle 11, 14, 22 for throttling the fuel flow. In order to form the throttles 11, 14, 22, the bores 8, 12 and 21 each have a reduced flow cross-section in the region of the underside of the throttle plate 7. The reduced flow cross section is followed in each case by a long outlet bore, which opens into the valve chamber 6 in the region of a radial widening, that is to say a spout. Both the long outflow holes, as well as the volume of the Schnaupen contribute to an undesirable increase in the volume of the valve chamber 6.

Bei dem in der Fig. 2 dargestellten erfindungsgemäßen Kraftstoffinjektor wird der Nachteil eines vergrößerten Ventilraumvolumens aufgrund des Einsatzes einer Hülse 18 zur Druckentlastung des Ventilgliedes 16 dadurch kompensiert, dass die Drossel 11 der Bohrung 8 in den Mündungsbereich der Bohrung 8 verlagert wurde. Eine lange den Ventilraum 6 vergrößernde Abströmbohrung entfällt somit. Des Weiteren wurde die Schnaupe durch einen Axialspalt 10 zwischen der Ventilplatte 5 und der Drosselplatte 7 ersetzt, über dessen Höhe h die Drosselwirkung beeinflussbar ist. Der Axialspalt 10 bildet somit einen Bestandteil der Drossel 11 aus. Die als Ablaufkanal dienende Bohrung 12 ist bei dem Ausführungsbeispiel der Fig. 2 weiterhin in herkömmlicher Weise ausgebildet, das heißt mit einer Drossel 14, die im unteren Bereich der Bohrung 12 ausgebildet ist und an welche sich eine lange Abströmbohrung anschließt. Alternativ kann aber auch die als Ablaufkanal dienende Bohrung 12 entsprechend der Bohrung 8 mit einer Drossel 14 im Mündungsbereich ausgebildet sein.In the in the Fig. 2 illustrated fuel injector according to the invention the disadvantage of an enlarged valve space volume due to the use of a sleeve 18 for pressure relief of the valve member 16 is compensated by the fact that the throttle 11 of the bore 8 has been moved into the mouth region of the bore 8. A long the valve chamber 6 enlarging discharge hole thus eliminated. Furthermore, the spout has been replaced by an axial gap 10 between the valve plate 5 and the throttle plate 7, over the height h of the throttle effect can be influenced. The axial gap 10 thus forms a part of the throttle 11. The serving as a drain passage bore 12 is in the embodiment of Fig. 2 further formed in a conventional manner, that is with a throttle 14, which is formed in the lower region of the bore 12 and to which a long outflow bore connects. Alternatively, however, also serving as a drain passage bore 12 may be formed according to the bore 8 with a throttle 14 in the mouth region.

Eine weitere alternative Ausführungsform der als Ablaufkanal dienenden Bohrung 12 geht aus dem in Fig. 3 dargestellten Ausführungsbeispiel eines erfindungsgemäßen Kraftstoffinjektors hervor. Im Unterschied zum Ausführungsbeispiel der Fig. 2 mündet die Bohrung 12 in einen Axialspalt 13, dessen Höhe h derart gewählt ist, dass ein Gegendruck auf den abströmenden Kraftstoff asugeübt wird. Der Gegendruck soll den Eintrag von Gasblasen in den Ventilraum 6 verringern. Der Axialspalt 13 weist hierzu eine Höhe h auf, die gegenüber der Höhe der in Fig. 1 dargestellten Schnaupe deutlich reduziert ist, so dass eine Verkleinerung des Ventilraumvolumens erreicht wird. Die Höhe h des Axialspalts 13 ist jedoch größer als die Höhe h des Axialspalts 10 gewählt, da innerhalb der Bohrung 12 bereits eine Ablaufdrossel 14 zur Drosselung des Kraftstoffstroms ausgebildet ist.Another alternative embodiment of serving as a drain passage bore 12 goes out of the in Fig. 3 illustrated embodiment of a fuel injector according to the invention. In contrast to the embodiment of Fig. 2 opens the bore 12 in an axial gap 13, the height h is selected such that a back pressure is applied to the outflowing fuel. The back pressure should reduce the entry of gas bubbles in the valve chamber 6. For this purpose, the axial gap 13 has a height h which is opposite to the height of the in Fig. 1 shown spout is significantly reduced, so that a reduction of the valve chamber volume is achieved. However, the height h of the axial gap 13 is greater than the height h of the axial gap 10 chosen, since within the bore 12 is already formed a flow restrictor 14 for throttling the fuel flow.

Claims (8)

  1. Fuel injector for a fuel injection system, with a nozzle needle (2), guided in reciprocating motion in a nozzle body (1), for closing and releasing at least one injection orifice formed in the nozzle body (1), and with a control valve (3) for the indirect activation of the nozzle needle (2), in that, when the control valve (3) being opened or closed, a control pressure acting upon the nozzle needle (2) in the closing direction is varied in a control space (4), the control valve (3) comprising a valve space (6) which is formed in a valve plate (5) and is delimited by a throttle plate (7) which is arranged between the nozzle body (1) and the valve plate (5) and in which at least one bore (8, 12) for connecting the valve space (6) to the control space (4) and/or to a high-pressure duct (9) is formed, the bore (8) issuing into the valve space (6) via an axial gap (10) formed between the valve plate (5) and the throttle plate (7) and possessing in the region of issue a reduced diameter d, so as to form a throttle (11, 14), the throttle action of which can be influenced via the height h of the axial gap (10), characterized in that the bore (8) connects the valve space (6) to the high-pressure duct (9), and the throttle (11) which serves as a filling throttle.
  2. Fuel injector according to Claim 1, characterized in that the height h of the axial gap (10, 13) amounts to ≤ 500 µm, preferably ≤ 100 µm, furthermore preferably ≤ 50 µm.
  3. Fuel injector according to one of the preceding claims, characterized in that, in the throttle plate (7), a further bore (12) is provided, which serves as an outflow duct and which connects the valve space (6) to the control space (4) and issues into the valve space (6) via a further axial gap (13) formed between the valve plate (5) and the throttle plate (7), the height h and the axial gap (13) being selected such that the fuel flowing out via the bore (12) experiences a counterpressure.
  4. Fuel injector according to Claim 3, characterized in that the further bore (12) connects the valve space (6) to the control space (4), and the throttle (14) serves as an outflow throttle.
  5. Fuel injector according to one of the preceding claims, characterized in that at least one bore (8, 12) is formed, at least in a sub region, so as to be rounded by hydroerosion.
  6. Fuel injector according to one of the preceding claims, characterized in that the control valve (3) comprises a reciprocal-motion valve member (16) which co-operates with a valve seat (15) and of which the end facing away from the valve seat is guided in a sleeve (18) bearing sealingly against the throttle plate (7) and delimiting a low-pressure space (17), so that the valve member (16) is relieved of pressure when it is in bearing contact on the valve seat (15).
  7. Fuel injector according to Claim 6, characterized in that the low-pressure space (17) is connected to a return (20) via a bore (19).
  8. Fuel injector according to one of the preceding claims, characterized in that a piezo-actuator is provided for actuating the control valve (3).
EP11150096.3A 2010-02-05 2011-01-04 Fuel injector Not-in-force EP2354527B1 (en)

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DE102010001612A DE102010001612A1 (en) 2010-02-05 2010-02-05 fuel injector

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DE102016217508A1 (en) 2016-09-14 2018-03-15 Robert Bosch Gmbh fuel injector
CN108131230B (en) * 2017-12-26 2024-03-08 南岳电控（衡阳）工业技术股份有限公司 High-pressure common rail heavy mechanical oil sprayer of diesel engine

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EP0976924B1 (en) * 1998-07-31 2003-09-17 Siemens Aktiengesellschaft Injector with a servo valve
GB0107575D0 (en) * 2001-03-27 2001-05-16 Delphi Tech Inc Control valve arrangement
US6955114B2 (en) * 2003-12-05 2005-10-18 Caterpillar Inc Three way valve and electro-hydraulic actuator using same
DE102004061800A1 (en) 2004-12-22 2006-07-06 Robert Bosch Gmbh Injector of a fuel injection system of an internal combustion engine
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EP2354527A2 (en) 2011-08-10
DE102010001612A1 (en) 2011-08-11
EP2354527A3 (en) 2013-07-31

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