EP1395744B1 - Fuel injection device for combustion motors, especially common rail injector, fuel system and internal combustion engine - Google Patents

Fuel injection device for combustion motors, especially common rail injector, fuel system and internal combustion engine Download PDF

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Publication number
EP1395744B1
EP1395744B1 EP02742681A EP02742681A EP1395744B1 EP 1395744 B1 EP1395744 B1 EP 1395744B1 EP 02742681 A EP02742681 A EP 02742681A EP 02742681 A EP02742681 A EP 02742681A EP 1395744 B1 EP1395744 B1 EP 1395744B1
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EP
European Patent Office
Prior art keywords
fuel
fuel injection
injection device
sleeve part
spring
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Expired - Lifetime
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EP02742681A
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German (de)
French (fr)
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EP1395744A1 (en
Inventor
Friedrich Boecking
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Robert Bosch GmbH
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Robert Bosch GmbH
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M47/00—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
    • F02M47/02—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure of accumulator-injector type, i.e. having fuel pressure of accumulator tending to open, and fuel pressure in other chamber tending to close, injection valves and having means for periodically releasing that closing pressure
    • F02M47/027—Electrically actuated valves draining the chamber to release the closing pressure

Definitions

  • the invention relates to a fuel injection device for internal combustion engines, in particular common rail injector, with a housing having an injection end, with a recess extending in the housing, with at least one axially movable valve element which is arranged in the recess with a Valve seat cooperates and has a pressure surface facing away from the injection end, which axially delimits a control chamber, with a sleeve member which limits the control chamber radially, and at least one device which the sleeve member against a first housing portion and the valve element in the direction of the injection End applied, wherein the device comprises separate biasing means, wherein each one biasing means acts on the valve element and another biasing means the sleeve part.
  • Such a fuel injection device is known from the market. It is a common rail injector.
  • the control chamber is limited by an axial end surface of a valve needle. Radially, the control chamber is limited by a sleeve part, in whose wall an inlet throttle is present. On the valve needle opposite side of the control chamber is limited by a housing part in which a drain throttle is present.
  • the inlet throttle is connected to a high-pressure inlet, whereas the drain throttle is connected via a control valve with a low-pressure region. The throttling effect of the inlet throttle is stronger than that of the drain throttle.
  • a compression spring is clamped between the sleeve part and an annular shoulder of the valve needle.
  • the valve needle is acted upon against a valve seat in the region of the injection end, and on the other hand, the sleeve part is acted upon against the housing part.
  • the pressure in the control chamber is lowered.
  • the closing force of the compression spring is overcome, so that moves the valve needle.
  • EP 1 118 765 A shows a generic device.
  • Object of the present invention is to develop a fuel injection device of the type mentioned so that with it the fuel can be injected even more precisely.
  • leaks between the sleeve part and the first housing section are equivalent to an enlarged cross section of the inlet throttle. at an existing leak between the sleeve part and the first housing portion can therefore flow at an initiated pressure drop in the control chamber of the fuel faster than desired in the control room, so that the pressure in the control room increases too quickly again. This leads to premature closing of the valve element.
  • Such a leak between the sleeve part and the first housing portion is avoided in the fuel injection device according to the invention.
  • the biasing device which acts on the valve element, must be relatively soft. Such individual embodiments of the corresponding biasing means are possible in the fuel injection device according to the invention.
  • the fuel injection device according to the invention thus allows an extremely inexpensive and simple way an optimal seal between the sleeve part and the first housing portion, which allows a precise and reproducible pressure curve in the control room. This in turn allows a precise opening and closing of the fuel injection device.
  • the seal is additionally improved by the fact that the sleeve part has a circumferential sharp edge, with which it bears against the first housing portion.
  • the pretensioning device which acts on the sleeve part, is supported on a second and stationary housing section. With such a support necessary for a good seal between the sleeve part and the first housing section forces can be well received.
  • an opening is present in the wall of the sleeve part, which forms an inlet flow throttle for the control chamber.
  • an inlet flow restrictor can be introduced into the sleeve part in a simple manner and with the highest precision.
  • the pretensioning device which acts on the sleeve part, to be supported on a shoulder of the recess in the housing. Since the recess in the housing, in which the valve element is arranged, is generally anyway formed as a stepped bore, such a shoulder can be provided without much additional effort.
  • the biasing means comprises a disc spring having an opening through which the valve element extends therethrough.
  • Such disc springs which If necessary, can also be arranged as a spring package, have a very high rigidity. With them, thus high contact pressure between the sleeve part and the first housing portion can be realized, which is advantageous for the desired seal. In addition, such disc springs build very compact.
  • At least one recess is present in the disc spring in the region of the radially outer edge.
  • the space in which the disc spring is arranged can also be used for the flow guidance of the fuel. The fuel can flow through the recess in this case.
  • the biasing means which acts on the sleeve part, comprise a spring sleeve.
  • a spring sleeve is generally in the shape of a cylinder and provides support in a location axially remote from the sleeve portion.
  • the wall of the spring sleeve at least one opening is present.
  • the space in which the spring sleeve is arranged also be used as a flow channel for the fuel. It is particularly preferred if an inlet flow restrictor is present in the wall of the spring sleeve.
  • Such an opening with a certain cross-section can be easily and inexpensively introduced into the spring sleeve, without adversely affecting their rigidity or life.
  • the biasing device which acts on the sleeve part, comprises a spring element with a support portion and at least two axially extending spring portions. Even with such a spring element, the support can axially from the sleeve part removed. Since the spring element comprises individual spring sections, between which intermediate spaces are present, the flow through the space in which the spring element is arranged, not or only slightly impaired.
  • the invention also relates to a fuel system with a fuel injection device which injects the fuel directly into the combustion chamber of an internal combustion engine, with at least one high-pressure fuel pump, and with a fuel manifold, to which the fuel injection device is connected.
  • the fuel injection device is formed in the above-mentioned manner.
  • the invention also relates to an internal combustion engine with at least one combustion chamber, in which the fuel is injected directly.
  • the internal combustion engine has a fuel system of the type mentioned above. Since the metering of the fuel into the combustion chamber is very precise with this fuel system, emissions can be kept low and fuel consumption kept low.
  • Fig. 1 carries a fuel injection device
  • the reference numeral 10 This is a common rail injector, which is used for the direct injection of highly compressed fuel into the combustion chamber of an internal combustion engine.
  • the injector 10 comprises a multi-part housing 12.
  • the housing 12 comprises a nozzle body 14 and an intermediate disk 16.
  • the nozzle body 14 and the intermediate disk 16 are braced against each other via a nozzle retaining nut, not shown in the drawing.
  • the lower end of the nozzle body 14 in FIG. 1 is designed as an injection end 18.
  • the nozzle body 14 extends in the longitudinal direction of a recess 20. This has the shape of a stepped bore and ends in the injection end 18.
  • a plurality of distributed over the circumference of the injection end 18 arranged fuel outlet openings 22 are present.
  • a Ventilelemnet 24 is arranged in the recess 20 in the nozzle body 14.
  • a valve needle which is coaxial with the recess 20 and is axially movable.
  • the valve needle 24 cooperates with a valve seat (without reference numeral) in the region of the injection end 18.
  • the valve needle 24 has a plurality of sections of different diameter: Between a smaller diameter section 26 and a larger diameter section 28, an inclined pressure surface 30 is present. Above section 28 there is a section 32 which has a smaller diameter than section 28. Above section 32, in turn, valve needle 24 has an end section 34 whose diameter is slightly larger than that of section 32. End section 34 retracts axially bounded above by a pressure surface 36.
  • the pressure surface 36 in turn limits axially a control chamber 38.
  • the control chamber 38 is limited by a sleeve member 40 which extends down to approximately at the level of the transition between the end portion 34 and the portion 32 of the valve needle 24.
  • the end portion 34 is guided tightly in the sleeve part 40.
  • the upper edge of the sleeve part 40 has a conical slope, so that a cutting-like biting edge 44 is formed, with which the sleeve part 40 rests against the intermediate disc 16.
  • the washer 16 limits the control chamber 38 upwards.
  • an intermediate disc 42 is arranged, passes through the opening of the portion 32 of the valve needle 24 with some play.
  • the washer is acted upon by an annular disc spring 46 upwards. With its radially outer edge, the disc spring 46 is supported on a shoulder 48 of the recess 20.
  • the portion 32 of the valve needle 24 passes through a central opening 47 of the disc spring 46 therethrough.
  • a helical compression spring 50 is supported on the disc spring 46.
  • the helical compression spring 50 is arranged coaxially with the valve needle 24.
  • the compression coil spring 50 is supported on an annular collar 52 of a guide sleeve 54.
  • the inner diameter of the guide sleeve 54 is slightly smaller than the outer diameter of the portion 28 of the valve needle 24. The guide sleeve 54 is therefore supported on the between the portion 28 and the portion 32 of the Valve needle 24 formed paragraph.
  • annular space 56th available between the sleeve part 40, the intermediate disc 42 and the guide sleeve 54 on the one hand and the wall of the recess 20 in the nozzle body 14 on the other hand. This is connected via a flow channel 58 with a high-pressure manifold 60. In the wall of the sleeve part 40, a bore is introduced in the upper region, which forms an inlet throttle 62.
  • a through hole 64 is provided in the radial center thereof, which has a portion with a small diameter, which forms a drain throttle 66.
  • the diameter of the inlet throttle 62 is smaller than that of the drain throttle 66.
  • the control chamber 38 is connected to a switching valve 68. This is again connected to a low pressure area (without reference number) on the outlet side.
  • the annular space 56 is connected by axial channels in the nozzle body 14, which are introduced into the wall of the recess 20, with an annular pressure chamber 70 which is present in the recess 20 at the level of the pressure surface 30. From the pressure chamber 70, another annular space 72, with open valve needle 24, leads to the fuel outlet openings 22. In the outer edge of the disc spring 46 distributed over the circumference a plurality of semi-circular recesses 74 are introduced. Through this, the area of the annular space 56 above the disc spring 46 is connected to the area below the disc spring 46. For the formation of the recesses 74 in the disc spring 46, reference is made to FIG.
  • the injector 10 shown in Fig. 1 operates as follows:
  • the switching valve 68 When the injector 10 is closed, the switching valve 68 is closed. In this case prevails in the control chamber 38 of the full system pressure, which in the high-pressure manifold 60, in the flow channel 58, in the inlet throttle 62 and in the annulus 56 prevails. This pressure acts on the pressure surface 36 at the upper end of the valve needle 24. In this way and by the action of the helical compression spring 50, the valve needle 24 is pressed against the injection end 18 of the nozzle body 14. The fuel outlet openings 22 are thus separated from the annular space 72, so that no fuel can escape.
  • the switching valve 68 is opened. Since the diameter of the outlet throttle 66 is greater than that of the inlet throttle 62, more fuel flows out of the control chamber 38 to the low pressure region than flows in again through the inlet throttle 62. Thus, the pressure in the control chamber 38. At the same time in the pressure chamber 70 is the full system pressure and acts on the pressure surface 30 on the valve needle 24. When the corresponding resultant force on the pressure surface 30, the closing force by the compression coil spring 50 and the pressure surface 36 outgoing force, lifts the valve needle 14 from the valve seat in the region of the injection end 18 and releases the fuel outlet openings 22 free.
  • the switching valve 68 is closed again.
  • fuel continues to flow into the control chamber 38 until the same pressure prevails in the control chamber 38 as in the annular space 56 and at all other locations within the injector 10.
  • the valve needle 24 is again moved toward the injection end 18 and the connection between the fuel outlet openings 22 and the annular space 72 is interrupted.
  • the pressure curve in the control chamber 38 must also correspond as closely as possible to the desired course.
  • the desired course is in turn influenced by an exact dimensioning on the one hand, the inlet throttle 62 and on the other hand, the drain throttle 66.
  • the disc spring 46 is very stiff. As a result, the biting edge 44 is pressed with a very high contact pressure against the wall of the washer 16, which creates an optimal seal. At the same time, however, the helical compression spring 50 is so soft that the opening operation of the valve needle 24 is not impaired.
  • FIG. 3 a second embodiment of an injector 10 is shown.
  • Such parts which are functionally equivalent to parts which have already been described in connection with FIGS. 1 and 2, bear the same reference numerals. They will not be discussed again in detail.
  • a spring sleeve 46 is provided in the injector shown in Fig. 3. This consists essentially of a hollow cylinder (see Fig. 4), in the wall in the azimuthal direction elongated openings 74 are present.
  • the upper edge of the spring sleeve 46 is supported on the between disc 42 from.
  • the lower edge of the spring sleeve 46 is supported on a shoulder 76, which is formed between a region 78 of the recess 20 with a larger diameter and a portion 80 of the recess 20 with a smaller diameter.
  • FIG. 5 A variant of such a spring sleeve is shown in Fig. 5.
  • This spring sleeve 46 has only a single opening in its wall, which forms an inlet throttle 62. Further, in this spring sleeve 46, two relatively stiff portions 82 and 84 are provided, between which a trained in accordion form spring portion 86 is arranged.
  • a spring element 46 is provided in the injector 10 shown in FIG. 6 instead of a disc spring.
  • This has an annular support portion 88, on which two axially extending spring portions 90 are formed.
  • a semicircular bulge 92 is in each case in the region of its lower end in Fig. 6, but slightly spaced therefrom (see also Fig. 7), which in each case forms a spiral spring.
  • an internal combustion engine 94 is shown schematically. It comprises a fuel system 96. This in turn has a fuel tank 98 from which a low-pressure electric fuel pump 100 the Fuel to a motor-driven high-pressure pump 102 promotes. From this fuel enters a fuel rail 104, which is commonly referred to as a "rail". To the fuel manifold 104, a plurality of injectors 10 are connected, which are formed according to FIG. 1, FIG. 3 or FIG. The injectors 10 each inject the fuel (diesel or gasoline) directly into combustion chambers 106.
  • top and bottom in the above description refer exclusively to the figures.
  • the device 10 can also be arranged in a different position than that shown in the figures.

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

Description

Stand der TechnikState of the art

Die Erfindung betrifft eine Kraftstoff-Einspritzvorrichtung für Brennkraftmaschinen, insbesondere Common-Rail-Injektor, mit einem Gehäuse mit einem Einspritz-Ende, mit einer in dem Gehäuse verlaufenden Ausnehmung, mit mindestens einem axial beweglichen Ventilelement, das in der Ausnehmung angeordnet ist, mit einem Ventilsitz zusammenarbeitet und eine vom Einspritz-Ende abgewandte Druckfläche aufweist, welche einen Steuerraum axial begrenzt, mit einem Hülsenteil, welches den Steuerraum radial begrenzt, und mit mindestens einer Einrichtung, welche das Hülsenteil gegen einen ersten Gehäuseabschnitt und das Ventilelement in Richtung auf das Einspritz-Ende beaufschlagt, wobei die Einrichtung separate Vorspanneinrichtungen umfasst, wobei jeweils eine Vorspanneinrichtung das Ventilelement und eine andere Vorspanneinrichtung das Hülsenteil beaufschlagt.The invention relates to a fuel injection device for internal combustion engines, in particular common rail injector, with a housing having an injection end, with a recess extending in the housing, with at least one axially movable valve element which is arranged in the recess with a Valve seat cooperates and has a pressure surface facing away from the injection end, which axially delimits a control chamber, with a sleeve member which limits the control chamber radially, and at least one device which the sleeve member against a first housing portion and the valve element in the direction of the injection End applied, wherein the device comprises separate biasing means, wherein each one biasing means acts on the valve element and another biasing means the sleeve part.

Eine derartige Kraftstoff-Einspritzvorrichtung ist vom Markt her bekannt. Bei ihr handelt es sich um einen Common-Rail-Injektor. Bei diesem wird der Steuerraum durch eine axiale Endfläche einer Ventilnadel begrenzt. Radial wird der Steuerraum durch ein Hülsenteil begrenzt, in dessen Wand eine Zulaufdrossel vorhanden ist. Auf der der Ventilnadel gegenüberliegenden Seite wird der Steuerraum durch ein Gehäuseteil begrenzt, in dem eine Ablauf-Drossel vorhanden ist. Die Zulauf-Drossel ist mit einem Hochdruckzulauf verbunden, wohingegen die Ablauf-Drossel über ein Steuerventil mit einem Niederdruckbereich verbunden ist. Die Drosselwirkung der Zulauf-Drossel ist stärker als jene der Ablauf-Drossel.Such a fuel injection device is known from the market. It is a common rail injector. In this case, the control chamber is limited by an axial end surface of a valve needle. Radially, the control chamber is limited by a sleeve part, in whose wall an inlet throttle is present. On the valve needle opposite side of the control chamber is limited by a housing part in which a drain throttle is present. The inlet throttle is connected to a high-pressure inlet, whereas the drain throttle is connected via a control valve with a low-pressure region. The throttling effect of the inlet throttle is stronger than that of the drain throttle.

Zwischen dem Hülsenteil und einem ringförmigen Absatz der Ventilnadel ist eine Druckfeder verspannt. Durch diese wird einerseits die Ventilnadel gegen einen Ventilsitz im Bereich des Einspritz-Endes beaufschlagt, und andererseits wird das Hülsenteil gegen das Gehäuseteil beaufschlagt. Um die Ventilnadel von ihrem Ventilsitz im Bereich des Einspritz-Endes abzuheben, wird der Druck im Steuerraum abgesenkt. An einer Druckfläche der Ventilnadel liegt weiterhin der normale Hochdruck an. Bei einer ausreichenden Druckdifferenz wird die Schließkraft der Druckfeder überwunden, so dass sich die Ventilnadel bewegt.Between the sleeve part and an annular shoulder of the valve needle, a compression spring is clamped. By this, on the one hand, the valve needle is acted upon against a valve seat in the region of the injection end, and on the other hand, the sleeve part is acted upon against the housing part. To lift the valve needle from its valve seat in the region of the injection end, the pressure in the control chamber is lowered. At a pressure surface of the valve needle is still the normal high pressure. At a sufficient pressure difference, the closing force of the compression spring is overcome, so that moves the valve needle.

Auch die EP 1 118 765 A zeigt eine gattungsgemäße Vorrichtung.Also EP 1 118 765 A shows a generic device.

Aufgabe der vorliegenden Erfindung ist, eine Kraftstoff-Einspritzvorrichtung der eingangs genannten Art so weiterzubilden, dass mit ihr der Kraftstoff noch präziser eingespritzt werden kann.Object of the present invention is to develop a fuel injection device of the type mentioned so that with it the fuel can be injected even more precisely.

Diese Aufgabe wird bei einer Kraftstoff-Einspritzvorrichtung der eingangs genannten Art dadurch gelöst, dass das Hülsenteil eine umlaufende scharfe Kante aufweist, mit der es an dem ersten Gehäuseabschnitt anliegt.This object is achieved in a fuel injection device of the type mentioned above in that the sleeve part has a circumferential sharp edge, with which it bears against the first housing portion.

Vorteile der ErfindungAdvantages of the invention

Erfindungsgemäß wurde erkannt, dass Undichtigkeiten zwischen dem Hülsenteil und dem ersten Gehäuseabschnitt äquivalent sind zu einem vergrößerten Querschnitt der Zulauf-Drossel. Bei einer vorhandenen Undichtigkeit zwischen dem Hülsenteil und dem ersten Gehäuseabschnitt kann daher bei einem eingeleiteten Druckabfall im Steuerraum der Kraftstoff schneller als gewünscht in den Steuerraum nachströmen, so dass der Druck im Steuerraum zu schnell wieder ansteigt. Dies führt zu einem vorzeitigen Schließen des Ventilelements. Eine derartige Undichtigkeit zwischen dem Hülsenteil und dem ersten Gehäuseabschnitt wird bei der erfindungsgemäßen Kraftstoff-Einspritzvorrichtung vermieden.According to the invention, it has been recognized that leaks between the sleeve part and the first housing section are equivalent to an enlarged cross section of the inlet throttle. at an existing leak between the sleeve part and the first housing portion can therefore flow at an initiated pressure drop in the control chamber of the fuel faster than desired in the control room, so that the pressure in the control room increases too quickly again. This leads to premature closing of the valve element. Such a leak between the sleeve part and the first housing portion is avoided in the fuel injection device according to the invention.

Dies erfolgt dadurch, dass die Kraft, mit welcher das Hülsenteil gegen den ersten Gehäuseabschnitt beaufschlagt wird, ausreichend hoch gewählt werden kann, so dass eine optimale Abdichtung zwischen Hülsenteil und erstem Gehäuseabschnitt vorliegt. Eine derartig hohe Anpresskraft ist jedoch nur dadurch möglich, dass einerseits für das Hülsenteil und andererseits für das Ventilelement jeweils separate Vorspanneinrichtungen vorgesehen sind.This is done by the force with which the sleeve part is acted upon against the first housing portion, can be chosen sufficiently high, so that there is an optimum seal between the sleeve part and the first housing portion. However, such a high contact pressure is only possible by the fact that on the one hand for the sleeve part and on the other hand for the valve element separate biasing means are provided.

Um die für die notwendige Abdichtung zwischen Hülsenteil und erstem Gehäuseabschnitt notwendige Anpresskraft bereitstellen zu können, ist nämlich eine sehr steife Feder erforderlich. Um andererseits eine Öffnungsbewegung des Ventilelements bereits bei einem geringen Druckabfall im Steuerraum bewirken zu können, muss die Vorspanneinrichtung, welche das Ventilelement beaufschlagt, relativ weich sein. Derartige individuelle Ausgestaltungen der entsprechenden Vorspanneinrichtungen sind bei der erfindungsgemäßen Kraftstoff-Einspritzvorrichtung möglich.In order to provide the necessary for the necessary seal between the sleeve part and the first housing portion pressing force, namely a very stiff spring is required. On the other hand, to be able to effect an opening movement of the valve element even at a low pressure drop in the control chamber, the biasing device, which acts on the valve element, must be relatively soft. Such individual embodiments of the corresponding biasing means are possible in the fuel injection device according to the invention.

Die erfindungsgemäße Kraftstoff-Einspritzvorrichtung gestattet somit auf äußerst preiswerte und einfache Art und Weise eine optimale Abdichtung zwischen Hülsenteil und erstem Gehäuseabschnitt, was einen präzisen und reproduzierbaren Druckverlauf im Steuerraum ermöglicht. Dies wiederum ermöglicht ein präzises Öffnen und Schließen der Kraftstoff-Einspritzvorrichtung.The fuel injection device according to the invention thus allows an extremely inexpensive and simple way an optimal seal between the sleeve part and the first housing portion, which allows a precise and reproducible pressure curve in the control room. This in turn allows a precise opening and closing of the fuel injection device.

Die Abdichtung wird zusätzlich noch dadurch verbessert, dass das Hülsenteil eine umlaufende scharfe Kante aufweist, mit der es an dem ersten Gehäuseabschnitt anliegt.The seal is additionally improved by the fact that the sleeve part has a circumferential sharp edge, with which it bears against the first housing portion.

Vorteilhafte Weiterbildungen der Erfindung sind in Unteransprüchen angegeben.Advantageous developments of the invention are specified in subclaims.

In einer ersten Weiterbildung ist genannt, dass sich die Vorspanneinrichtung, welche das Hülsenteil beaufschlagt, an einem zweiten und stationären Gehäuseabschnitt abstützt. Mit einer solchen Abstützung können die für eine gute Abdichtung zwischen Hülsenteil und erstem Gehäuseabschnitt notwendigen Kräfte gut aufgenommen werden.In a first development, it is mentioned that the pretensioning device, which acts on the sleeve part, is supported on a second and stationary housing section. With such a support necessary for a good seal between the sleeve part and the first housing section forces can be well received.

Vorteilhafterweise ist in der Wand des Hülsenteils eine Öffnung vorhanden, welche eine Zulauf-Strömungsdrossel für den Steuerraum bildet. Eine solche Zulauf-Strömungsdrossel ist in das Hülsenteil auf einfache Art und Weise und mit höchster Präzision einbringbar.Advantageously, an opening is present in the wall of the sleeve part, which forms an inlet flow throttle for the control chamber. Such an inlet flow restrictor can be introduced into the sleeve part in a simple manner and with the highest precision.

Ferner ist es möglich, dass sich die Vorspanneinrichtung, welche das Hülsenteil beaufschlagt, an einem Absatz der Ausnehmung im Gehäuse abstützt. Da die Ausnehmung im Gehäuse, in welcher das Ventilelement angeordnet ist, im Allgemeinen sowieso als Stufenbohrung ausgebildet ist, kann ein derartiger Absatz ohne großen Mehraufwand vorgesehen werden.Furthermore, it is possible for the pretensioning device, which acts on the sleeve part, to be supported on a shoulder of the recess in the housing. Since the recess in the housing, in which the valve element is arranged, is generally anyway formed as a stepped bore, such a shoulder can be provided without much additional effort.

Eine vorteilhafte Möglichkeit zur Ausgestaltung der Vorspanneinrichtung für das Hülsenteil besteht darin, dass die Vorspanneinrichtung eine Scheibenfeder mit einer Öffnung umfasst, durch welde sich das Ventilelement hindurch erstreckt. Derartige Scheibenfedern, welche gegebenenfalls auch als Federpaket angeordnet werden können, weisen eine sehr große Steifigkeit auf. Mit ihnen können somit hohe Anpresskräfte zwischen dem Hülsenteil und dem ersten Gehäuseabschnitt realisiert werden, was für die gewünschte Abdichtung vorteilhaft ist. Darüber hinaus bauen derartige Scheibenfedern sehr kompakt.An advantageous possibility for the design of the biasing means for the sleeve part is that the biasing means comprises a disc spring having an opening through which the valve element extends therethrough. Such disc springs, which If necessary, can also be arranged as a spring package, have a very high rigidity. With them, thus high contact pressure between the sleeve part and the first housing portion can be realized, which is advantageous for the desired seal. In addition, such disc springs build very compact.

Bei einer Weiterbildung ist in der Scheibenfeder im Bereich des radial äußeren Randes mindestens eine Ausnehmung vorhanden. In diesem Fall kann der Raum, in dem die Scheibenfeder angeordnet ist, auch für die Strömungsführung des Kraftstoffes verwendet werden. Der Kraftstoff kann in diesem Fall durch die Ausnehmung hindurchströmen.In a further development, at least one recess is present in the disc spring in the region of the radially outer edge. In this case, the space in which the disc spring is arranged can also be used for the flow guidance of the fuel. The fuel can flow through the recess in this case.

Alternativ kann die Vorspanneinrichtung, welche das Hülsenteil beaufschlagt, eine Federhülse umfassen. Eine solche Federhülse hat im Allgemeinen die Form eines Zylinders und ermöglicht eine Abstützung in einer axial vom Hülsenteil entfernten Stelle.Alternatively, the biasing means, which acts on the sleeve part, comprise a spring sleeve. Such a spring sleeve is generally in the shape of a cylinder and provides support in a location axially remote from the sleeve portion.

Dabei wird bevorzugt, wenn in der Wand der Federhülse mindestens eine Öffnung vorhanden ist. In diesem Fall kann der Raum, in dem die Federhülse angeordnet ist, ebenfalls als Strömungskanal für den Kraftstoff verwendet werden. Besonders bevorzugt ist dabei, wenn in der Wand der Federhülse eine Zulauf-Strömungsdrossel vorhanden ist. Eine derartige Öffnung mit einem bestimmten Querschnitt kann leicht und preiswert in die Federhülse eingebracht werden, ohne deren Steifigkeit oder Lebensdauer nachteilig zu beeinflussen.It is preferred if in the wall of the spring sleeve at least one opening is present. In this case, the space in which the spring sleeve is arranged, also be used as a flow channel for the fuel. It is particularly preferred if an inlet flow restrictor is present in the wall of the spring sleeve. Such an opening with a certain cross-section can be easily and inexpensively introduced into the spring sleeve, without adversely affecting their rigidity or life.

Möglich ist auch, dass die Vorspanneinrichtung, welche das Hülsenteil beaufschlagt, ein Federelement mit einem Stützabschnitt und mindestens zwei axial verlaufenden Federabschnitten umfasst. Auch bei einem solchen Federelement kann die Abstützung axial vom Hülsenteil entfernt erfolgen. Da das Federelement einzelne Federabschnitte umfasst, zwischen denen Zwischenräume vorhanden sind, ist die Strömung durch den Raum, in dem das Federelement angeordnet ist, nicht oder nur gering beeinträchtigt.It is also possible that the biasing device, which acts on the sleeve part, comprises a spring element with a support portion and at least two axially extending spring portions. Even with such a spring element, the support can axially from the sleeve part removed. Since the spring element comprises individual spring sections, between which intermediate spaces are present, the flow through the space in which the spring element is arranged, not or only slightly impaired.

Die Erfindung betrifft auch ein Kraftstoffsystem mit einer Kraftstoff-Einspritzvorrichtung, welche den Kraftstoff direkt in den Brennraum einer Brennkraftmaschine einspritzt, mit mindestens einer Hochdruck-Kraftstoffpumpe, und mit einer Kraftstoff-Sammelleitung, an die die Kraftstoff-Einspritzvorrichtung angeschlossen ist.The invention also relates to a fuel system with a fuel injection device which injects the fuel directly into the combustion chamber of an internal combustion engine, with at least one high-pressure fuel pump, and with a fuel manifold, to which the fuel injection device is connected.

Um bei einem solchen Kraftstoffsystem die Präzision der durchgeführten Einspritzungen zu verbessern, wird vorgeschlagen, dass die Kraftstoff-Einspritzvorrichtung nach der oben genannten Art ausgebildet ist.In order to improve the precision of the injections performed in such a fuel system, it is proposed that the fuel injection device is formed in the above-mentioned manner.

Ferner betrifft die Erfindung noch eine Brennkraftmaschine mit mindestens einem Brennraum, in den der Kraftstoff direkt eingespritzt wird.Furthermore, the invention also relates to an internal combustion engine with at least one combustion chamber, in which the fuel is injected directly.

Um den Betrieb dieser Brennkraftmaschine im Hinblick auf den Kraftstoffverbrauch und die Emissionen zu optimieren, wird vorgeschlagen, dass die Brennkraftmaschine ein Kraftstoffsystem der oben genannten Art aufweist. Da mit diesem Kraftstoffsystem die Zumessung des Kraftstoffs in den Brennraum sehr präzise erfolgt, können die Emissionen niedrig und der Kraftstoffverbrauch gering gehalten werden.In order to optimize the operation of this internal combustion engine in terms of fuel consumption and emissions, it is proposed that the internal combustion engine has a fuel system of the type mentioned above. Since the metering of the fuel into the combustion chamber is very precise with this fuel system, emissions can be kept low and fuel consumption kept low.

Zeichnungdrawing

Nachfolgend werden Ausführungsbeispiele der Erfindung unter Bezugnahme auf die beiliegende Zeichnung im Detail erläutert. In der Zeichnung zeigen:

Fig. 1:
einen teilweisen Längsschnitt durch ein erstes Ausführungsbeispiel einer Kraftstoff-Einspritzvorrichtung für Brennkraftmaschinen, mit einer Vorspanneinrichtung für ein Hülsenteil;
Fig. 2:
eine Draufsicht auf die Vorspanneinrichtung vn Fig. 1;
Fig. 3:
einen teilweisen Längsschnitt durch einen Bereich eines zweiten Ausführungsbeispiels einer Kraftstoff-Einspritzvorrichtung für Brennkraftmaschinen, mit einer Vorspanneinrichtung für ein Hülsenteil;
Fig. 4:
eine perspektivische Darstellung der Vorspanneinrichtung von Fig. 3;
Fig. 5:
eine Abwandlung der Vorspanneinrichtung von Fig. 4;
Fig. 6:
eine Ansicht ähnlich Fig. 1 eines dritten Ausführungsbeispiels einer Kraftstoff-Einspritzvorrichtung für Brennkraftmaschinen, mit einer Vorspanneinrichtung für ein Hülsenteil;
Fig. 7:
eine perspektivische Darstellung der Vorspanneinrichtung von Fig. 6; und
Fig. 8:
eine Prinzipdarstellung einer Brennkraftmaschine mit einem Kraftstoffsystem und mehreren Kraftstoff-Einspritzvorrichtungen entsprechend Fig. 1.
Hereinafter, embodiments of the invention will be explained in detail with reference to the accompanying drawings. In the drawing show:
Fig. 1:
a partial longitudinal section through a first embodiment of a fuel injection device for internal combustion engines, with a biasing means for a sleeve part;
Fig. 2:
a plan view of the biasing device vn Fig. 1;
3:
a partial longitudinal section through a portion of a second embodiment of a fuel injection device for internal combustion engines, with a biasing means for a sleeve part;
4:
a perspective view of the biasing device of Fig. 3;
Fig. 5:
a modification of the biasing device of Fig. 4;
Fig. 6:
a view similar to Figure 1 of a third embodiment of a fuel injection device for internal combustion engines, with a biasing means for a sleeve part.
Fig. 7:
a perspective view of the biasing device of Fig. 6; and
Fig. 8:
a schematic diagram of an internal combustion engine with a fuel system and a plurality of fuel injection devices according to FIG. 1.

Beschreibung der AusführungsbeispieleDescription of the embodiments

In Fig. 1 trägt eine Kraftstoff-Einspritzvorrichtung insgesamt das Bezugszeichen 10. Bei ihr handelt es sich um einen Common-Rail-Injektor, welcher für die direkte Einspritzung hochverdichteten Kraftstoffs in den Brennraum einer Brennkraftmaschine verwendet wird. Der Injektor 10 umfasst ein mehrteiliges Gehäuse 12. Das Gehäuse 12 umfasst einen Düsenkörper 14 und eine Zwischenscheibe 16. Der Düsenkörper 14 und die Zwischenscheibe 16 sind über eine in der Zeichnung nicht dargestellte Düsenspannmutter gegeneinander verspannt.In Fig. 1 carries a fuel injection device Overall, the reference numeral 10. This is a common rail injector, which is used for the direct injection of highly compressed fuel into the combustion chamber of an internal combustion engine. The injector 10 comprises a multi-part housing 12. The housing 12 comprises a nozzle body 14 and an intermediate disk 16. The nozzle body 14 and the intermediate disk 16 are braced against each other via a nozzle retaining nut, not shown in the drawing.

Das in Fig. 1 untere Ende des Düsenkörpers 14 ist als Einspritz-Ende 18 ausgebildet. Im Düsenkörper 14 verläuft in dessen Längsrichtung eine Ausnehmung 20. Diese hat die Form einer Stufenbohrung und endet im Einspritz-Ende 18. Am Einspritz-Ende 18 sind mehrere über den Umfang des Einspritz-Endes 18 verteilt angeordnete Kraftstoff-Austrittsöffnungen 22 vorhanden. In der Ausnehmung 20 im Düsenkörper 14 ist ein Ventilelemnet 24 angeordnet. Bei ihm handelt es sich um eine Ventilnadel, welche koaxial zur Ausnehmung 20 verläuft und axial beweglich ist. Die Ventilnadel 24 arbeitet mit einem Ventilsitz (ohne Bezugszeichen) im Bereich des Einspritz-Endes 18 zusammen.The lower end of the nozzle body 14 in FIG. 1 is designed as an injection end 18. In the nozzle body 14 extends in the longitudinal direction of a recess 20. This has the shape of a stepped bore and ends in the injection end 18. At the injection end 18 a plurality of distributed over the circumference of the injection end 18 arranged fuel outlet openings 22 are present. In the recess 20 in the nozzle body 14, a Ventilelemnet 24 is arranged. For him it is a valve needle, which is coaxial with the recess 20 and is axially movable. The valve needle 24 cooperates with a valve seat (without reference numeral) in the region of the injection end 18.

Die Ventilnadel 24 weist mehrere Abschnitte mit unterschiedlichem Durchmesser auf: Zwischen einem Abschnitt 26 mit kleinerem Durchmesser und einem Abschnitt 28 mit größerem Durchmesser ist eine schräge Druckfläche 30 vorhanden. Oberhalb des Abschnitts 28 ist ein Abschnitt 32 vorhanden, der kleineren Durchmesser hat als der Abschnitt 28. Oberhalb des Abschnitts 32 wiederum weist die Ventilnadel 24 einen Endabschnitt 34 auf, dessen Durchmesser etwas größer ist als der des Abschnitts 32. Der Endabschnitt 34 wird axial nach oben durch eine Druckfläche 36 begrenzt.The valve needle 24 has a plurality of sections of different diameter: Between a smaller diameter section 26 and a larger diameter section 28, an inclined pressure surface 30 is present. Above section 28 there is a section 32 which has a smaller diameter than section 28. Above section 32, in turn, valve needle 24 has an end section 34 whose diameter is slightly larger than that of section 32. End section 34 retracts axially bounded above by a pressure surface 36.

Die Druckfläche 36 begrenzt wiederum axial einen Steuerraum 38. Radial wird der Steuerraum 38 durch ein Hülsenteil 40 begrenzt, welches sich nach unten bis etwa auf Höhe des Übergangs zwischen dem Endabschnitt 34 und dem Abschnitt 32 der Ventilnadel 24 erstreckt. Der Endabschnitt 34 ist in dem Hülsenteil 40 dicht geführt. Der obere Rand des Hülsenteils 40 weist eine konische Schräge auf, so dass eine schneidenartige Beißkante 44 gebildet wird, mit welcher das Hülsenteil 40 an der Zwischenscheibe 16 anliegt. Die Zwischenscheibe 16 begrenzt den Steuerraum 38 nach oben.The pressure surface 36 in turn limits axially a control chamber 38. Radially, the control chamber 38 is limited by a sleeve member 40 which extends down to approximately at the level of the transition between the end portion 34 and the portion 32 of the valve needle 24. The end portion 34 is guided tightly in the sleeve part 40. The upper edge of the sleeve part 40 has a conical slope, so that a cutting-like biting edge 44 is formed, with which the sleeve part 40 rests against the intermediate disc 16. The washer 16 limits the control chamber 38 upwards.

Unterhalb des Hülsenteils 40 ist eine Zwischenscheibe 42 angeordnet, durch deren Öffnung der Abschnitt 32 der Ventilnadel 24 mit etwas Spiel hindurchtritt. Die Zwischenscheibe wird von einer ringförmigen Scheibenfeder 46 nach oben beaufschlagt. Mit ihrem radial äußeren Rand stützt sich die Scheibenfeder 46 an einem Absatz 48 der Ausnehmung 20 ab. Der Abschnitt 32 der Ventilnadel 24 tritt durch eine mittige Öffnung 47 der Scheibenfeder 46 hindurch.Below the sleeve part 40, an intermediate disc 42 is arranged, passes through the opening of the portion 32 of the valve needle 24 with some play. The washer is acted upon by an annular disc spring 46 upwards. With its radially outer edge, the disc spring 46 is supported on a shoulder 48 of the recess 20. The portion 32 of the valve needle 24 passes through a central opening 47 of the disc spring 46 therethrough.

An der Scheibenfeder 46 wiederum stützt sich eine Schrauben-Druckfeder 50 ab. Die Schrauben-Druckfeder 50 ist koaxial zur Ventilnadel 24 angeordnet. Nach unten hin stützt sich die Schrauben-Druckfeder 50 an einem Ringkragen 52 einer Führungshülse 54 ab. Die Scheibenfeder 46 und die Schrauben-Druckfeder 50 sind Teil einer Beaufschlagungseinrichtung 55. Der Innendurchmesser der Führungshülse 54 ist etwas kleiner als der Außendurchmesser des Abschnitts 28 der Ventilnadel 24. Die Führungshülse 54 stützt sich daher an dem zwischen dem Abschnitt 28 und dem Abschnitt 32 der Ventilnadel 24 gebildeten Absatz ab.In turn, a helical compression spring 50 is supported on the disc spring 46. The helical compression spring 50 is arranged coaxially with the valve needle 24. Towards the bottom, the compression coil spring 50 is supported on an annular collar 52 of a guide sleeve 54. The inner diameter of the guide sleeve 54 is slightly smaller than the outer diameter of the portion 28 of the valve needle 24. The guide sleeve 54 is therefore supported on the between the portion 28 and the portion 32 of the Valve needle 24 formed paragraph.

Zwischen dem Hülsenteil 40, der Zwischenscheibe 42 und der Führungshülse 54 einerseits und der Wand der Ausnehmung 20 im Düsenkörper 14 andererseits ist ein Ringraum 56 vorhanden. Dieser ist über einen Strömungskanal 58 mit einer Hochdruck-Sammelleitung 60 verbunden. In die Wand des Hülsenteils 40 ist in deren oberen Bereich eine Bohrung eingebracht, welche eine Zulauf-Drossel 62 bildet.Between the sleeve part 40, the intermediate disc 42 and the guide sleeve 54 on the one hand and the wall of the recess 20 in the nozzle body 14 on the other hand, an annular space 56th available. This is connected via a flow channel 58 with a high-pressure manifold 60. In the wall of the sleeve part 40, a bore is introduced in the upper region, which forms an inlet throttle 62.

In der Zwischenscheibe 16 ist in deren radialer Mitte eine Durchgangsbohrung 64 vorhanden, welche einen Abschnitt mit einem geringen Durchmesser aufweist, der eine Ablauf-Drossel 66 bildet. Der Durchmesser der Zulauf-Drossel 62 ist kleiner als jener der Ablauf-Drossel 66. Über die Durchgangsbohrung 64 mit der Ablauf-Drossel 66 ist der Steuerraum 38 mit einem Schaltventil 68 verbunden. Dieses ist auslassseitig wiederum an einen Niederdruckbereich (ohne Bezugszeichen) angeschlossen.In the intermediate disc 16, a through hole 64 is provided in the radial center thereof, which has a portion with a small diameter, which forms a drain throttle 66. The diameter of the inlet throttle 62 is smaller than that of the drain throttle 66. About the through hole 64 with the drain throttle 66, the control chamber 38 is connected to a switching valve 68. This is again connected to a low pressure area (without reference number) on the outlet side.

Der Ringraum 56 ist durch axiale Kanäle im Düsenkörper 14, welche in die Wand der Ausnehmung 20 eingebracht sind, mit einem ringförmigen Druckraum 70 verbunden, welcher in der Ausnehmung 20 auf Höhe der Druckfläche 30 vorhanden ist. Vom Druckraum 70 führt ein weiterer Ringraum 72, bei geöffneter Ventilnadel 24, bis zu den Kraftstoff-Austrittsöffnungen 22. In den äußeren Rand der Scheibenfeder 46 sind über den Umfang verteilt mehrere halbkreisförmige Ausnehmungen 74 eingebracht. Durch diese ist der Bereich des Ringraums 56 oberhalb der Scheibenfeder 46 mit dem Bereich unterhalb der Scheibenfeder 46 verbunden. Zur Ausbildung der Ausnehmungen 74 in der Scheibenfeder 46 wird auf Fig. 2 verwiesen.The annular space 56 is connected by axial channels in the nozzle body 14, which are introduced into the wall of the recess 20, with an annular pressure chamber 70 which is present in the recess 20 at the level of the pressure surface 30. From the pressure chamber 70, another annular space 72, with open valve needle 24, leads to the fuel outlet openings 22. In the outer edge of the disc spring 46 distributed over the circumference a plurality of semi-circular recesses 74 are introduced. Through this, the area of the annular space 56 above the disc spring 46 is connected to the area below the disc spring 46. For the formation of the recesses 74 in the disc spring 46, reference is made to FIG.

Der in Fig. 1 dargestellte Injektor 10 arbeitet folgendermaßen:The injector 10 shown in Fig. 1 operates as follows:

Bei geschlossenem Injektor 10 ist das Schaltventil 68 geschlossen. In diesem Fall herrscht im Steuerraum 38 der volle Systemdruck, welcher auch in der Hochdruck-Sammelleitung 60, im Strömungskanal 58, in der Zulauf-Drossel 62 und im Ringraum 56 herrscht. Dieser Druck wirkt auf die Druckfläche 36 am oberen Ende der Ventilnadel 24. Hierdurch und durch die Wirkung der Schrauben-Druckfeder 50 wird die Ventilnadel 24 gegen das Einspritzende 18 des Düsenkörpers 14 gedrückt. Die Kraftstoff-Austrittsöffnungen 22 sind somit vom Ringraum 72 getrennt, so dass kein Kraftstoff austreten kann.When the injector 10 is closed, the switching valve 68 is closed. In this case prevails in the control chamber 38 of the full system pressure, which in the high-pressure manifold 60, in the flow channel 58, in the inlet throttle 62 and in the annulus 56 prevails. This pressure acts on the pressure surface 36 at the upper end of the valve needle 24. In this way and by the action of the helical compression spring 50, the valve needle 24 is pressed against the injection end 18 of the nozzle body 14. The fuel outlet openings 22 are thus separated from the annular space 72, so that no fuel can escape.

Um mit dem Injektor 10 eine Einspritzung durchzuführen, wird das Schaltventil 68 geöffnet. Da der Durchmesser der Ablauf-Drossel 66 größer ist als jener der Zulauf-Drossel 62, strömt mehr Kraftstoff aus dem Steuerraum 38 zum Niederdruckbereich ab als durch die Zulauf-Drossel 62 wieder zuströmt. Somit sinkt der Druck im Steuerraum 38. Gleichzeitig liegt im Druckraum 70 der volle Systemdruck an und wirkt auf die Druckfläche 30 an der Ventilnadel 24. Wenn die entsprechende resultierende Kraft an der Druckfläche 30 die Schließkraft durch die Schrauben-Druckfeder 50 und die von der Druckfläche 36 ausgehende Kraft übersteigt, hebt die Ventilnadel 14 vom Ventilsitz im Bereich des Einspritz-Endes 18 ab und gibt die Kraftstoff-Austrittsöffnungen 22 frei.In order to perform an injection with the injector 10, the switching valve 68 is opened. Since the diameter of the outlet throttle 66 is greater than that of the inlet throttle 62, more fuel flows out of the control chamber 38 to the low pressure region than flows in again through the inlet throttle 62. Thus, the pressure in the control chamber 38. At the same time in the pressure chamber 70 is the full system pressure and acts on the pressure surface 30 on the valve needle 24. When the corresponding resultant force on the pressure surface 30, the closing force by the compression coil spring 50 and the pressure surface 36 outgoing force, lifts the valve needle 14 from the valve seat in the region of the injection end 18 and releases the fuel outlet openings 22 free.

Um eine Einspritzung zu beenden, wird das Schaltventil 68 wieder geschlossen. Durch die Zulauf-Drossel 62 strömt weiterhin Kraftstoff in den Steuerraum 38 zu, bis im Steuerraum 38 der gleiche Druck herrscht wie im Ringraum 56 und an allen anderen Stellen innerhalb des Injektors 10. Durch den Druck auf die Druckfläche 36 der Ventilnadel 24 und aufgrund der Kraft, welche von der Schrauben-Druckfeder 50 auf die Ventilnadel 24 ausgeübt wird, wird die Ventilnadel 24 wieder in Richtung auf das Einspritz-Ende 18 bewegt und die Verbindung zwischen den Kraftstoff-Austrittsöffnungen 22 und dem Ringraum 72 unterbrochen.To end an injection, the switching valve 68 is closed again. Through the inlet throttle 62 fuel continues to flow into the control chamber 38 until the same pressure prevails in the control chamber 38 as in the annular space 56 and at all other locations within the injector 10. By the pressure on the pressure surface 36 of the valve needle 24 and due to the Force exerted by the compression coil spring 50 on the valve needle 24, the valve needle 24 is again moved toward the injection end 18 and the connection between the fuel outlet openings 22 and the annular space 72 is interrupted.

Damit der Schließzeitpunkt der Ventilnadel 24 möglichst exakt dem gewünschten Wert entspricht, muss der Druckverlauf im Steuerraum 38 ebenfalls möglichst exakt dem gewünschten Verlauf entsprechen. Der gewünschte Verlauf wird wiederum durch eine exakte Dimensionierung einerseits der Zulauf-Drossel 62 und andererseits der Ablauf-Drossel 66 beeinflusst.So that the closing time of the valve needle 24 as possible exactly corresponds to the desired value, the pressure curve in the control chamber 38 must also correspond as closely as possible to the desired course. The desired course is in turn influenced by an exact dimensioning on the one hand, the inlet throttle 62 and on the other hand, the drain throttle 66.

Um zu verhindern, dass Kraftstoff vom Ringraum 56 durch einen Spalt zwischen dem Hülsenteil 40 und der Zwischenscheibe 16 in den Steuerraum 38 gelangt (dies entspräche einem größeren Durchmesser der Zulaufdrossel 62), ist die Scheibenfeder 46 sehr steif ausgebildet. Hierdurch wird die Beißkante 44 mit sehr hoher Anpresskraft gegen die Wand der Zwischenscheibe 16 gedrückt, was eine optimale Abdichtung schafft. Gleichzeitig ist die Schrauben-Druckfeder 50 jedoch so weich, dass der Öffnungsvorgang der Ventilnadel 24 nicht beeinträchtigt wird.To prevent fuel from the annular space 56 passes through a gap between the sleeve member 40 and the washer 16 in the control chamber 38 (this would correspond to a larger diameter of the inlet throttle 62), the disc spring 46 is very stiff. As a result, the biting edge 44 is pressed with a very high contact pressure against the wall of the washer 16, which creates an optimal seal. At the same time, however, the helical compression spring 50 is so soft that the opening operation of the valve needle 24 is not impaired.

In Fig. 3 ist ein zweites Ausführungsbeispiel eines Injektors 10 dargestellt. Solche Teile, welche funktionsäquivalent sind zu Teilen, die bereits im Zusammenhang mit den Fig. 1 und 2 beschrieben worden sind, tragen die gleichen Bezugszeichen. Auf sie wird nicht nochmals im Detail eingegangen.In Fig. 3, a second embodiment of an injector 10 is shown. Such parts, which are functionally equivalent to parts which have already been described in connection with FIGS. 1 and 2, bear the same reference numerals. They will not be discussed again in detail.

Die wesentlichen Unterschiede betreffen die Ausgestaltung der Vorspanneinrichtung, welche das Hülsenteil 40 gegen die Zwischenscheibe 16 beaufschlagt. Anstelle einer Scheibenfeder ist bei dem in Fig. 3 dargestellten Injektor eine Federhülse 46 vorgesehen. Diese besteht im Wesentlichen aus einem Hohlzylinder (vgl. Fig. 4), in dessen Wand in azimutaler Richtung längliche Öffnungen 74 vorhanden sind.The main differences relate to the design of the biasing device, which acts on the sleeve member 40 against the washer 16. Instead of a disc spring, a spring sleeve 46 is provided in the injector shown in Fig. 3. This consists essentially of a hollow cylinder (see Fig. 4), in the wall in the azimuthal direction elongated openings 74 are present.

Der obere Rand der Federhülse 46 stützt sich an der zwischenscheibe 42 ab. Der untere Rand der Federhülse 46 stützt sich an einem Absatz 76 ab, welcher zwischen einem Bereich 78 der Ausnehmung 20 mit größerem Durchmesser und einem Bereich 80 der Ausnehmung 20 mit kleinerem Durchmesser gebildet ist. Durch die Ausnehmungen 74 in der Federhülse 46 kann Krafttoff hindurchtreten.The upper edge of the spring sleeve 46 is supported on the between disc 42 from. The lower edge of the spring sleeve 46 is supported on a shoulder 76, which is formed between a region 78 of the recess 20 with a larger diameter and a portion 80 of the recess 20 with a smaller diameter. Through the recesses 74 in the spring sleeve 46 Krafttoff can pass.

Eine Variante einer solchen Federhülse ist in Fig. 5 dargestellt. Diese Federhülse 46 weist nur eine einzige Öffnung in ihrer Wand auf, welche eine Zulauf-Drossel 62 bildet. Ferner sind bei dieser Federhülse 46 zwei relativ steife Abschnitte 82 und 84 vorhanden, zwischen denen ein in Ziehharmonikaform ausgebildeter Federabschnitt 86 angeordnet ist.A variant of such a spring sleeve is shown in Fig. 5. This spring sleeve 46 has only a single opening in its wall, which forms an inlet throttle 62. Further, in this spring sleeve 46, two relatively stiff portions 82 and 84 are provided, between which a trained in accordion form spring portion 86 is arranged.

In Fig. 6 ist ein weiteres Ausführungsbeispiel eines Injektors 10 dargestellt. Auch hier gilt, dass solche Teile, welche äquivalente Funktionen zu Teilen aufweisen, die im Zusammenhang mit den Fig. 1 - 5 beschrieben wurden, die gleichen Bezugszeichen tragen und hier nicht nochmals im Detail erläutert sind.6, another embodiment of an injector 10 is shown. Again, it is true that those parts which have equivalent functions to parts, which were described in connection with FIGS. 1-5, bear the same reference numerals and are not explained again in detail here.

Im Unterschied zu dem in Fig. 1 dargestellten Injektor 10 ist bei dem in Fig. 6 dargestellten Injektor 10 anstelle einer Scheibenfeder ein Federelement 46 vorgesehen. Dieses weist einen ringförmigen Stützabschnitt 88 auf, an den zwei axial verlaufende Federabschnitte 90 angeformt sind. In die Federabschnitte 90 ist im Bereich ihres in Fig. 6 unteren Endes, jedoch etwas von diesem beabstandet, jeweils eine halbkreisförmige Ausbuchtung 92 eingebogen (vgl. auch Fig. 7), die jeweils eine Biegefeder bildet.In contrast to the injector 10 shown in Fig. 1, a spring element 46 is provided in the injector 10 shown in FIG. 6 instead of a disc spring. This has an annular support portion 88, on which two axially extending spring portions 90 are formed. In the spring sections 90, a semicircular bulge 92 is in each case in the region of its lower end in Fig. 6, but slightly spaced therefrom (see also Fig. 7), which in each case forms a spiral spring.

In Fig. 8 ist schematisch eine Brennkraftmaschine 94 dargestellt. Sie umfasst ein Kraftstoffsystem 96. Dieses weist wiederum einen Kraftstoffbehälter 98 auf, aus dem eine elektrische Niederdruck-Kraftstoffpumpe 100 den Kraftstoff zu einer motorgetriebenen Hochdruckpumpe 102 fördert. Von dieser gelangt der Kraftstoff in eine Kraftstoff-Sammelleitung 104, welche gemeinhin auch als "Rail" bezeichnet wird. An die Kraftstoff-Sammelleitung 104 sind mehrere Injektoren 10 angeschlossen, die entsprechend Fig. 1, Fig. 3 oder Fig. 6 ausgebildet sind. Die Injektoren 10 spritzen jeweils den Kraftstoff (Diesel oder Benzin) direkt in Brennräume 106 ein.In Fig. 8, an internal combustion engine 94 is shown schematically. It comprises a fuel system 96. This in turn has a fuel tank 98 from which a low-pressure electric fuel pump 100 the Fuel to a motor-driven high-pressure pump 102 promotes. From this fuel enters a fuel rail 104, which is commonly referred to as a "rail". To the fuel manifold 104, a plurality of injectors 10 are connected, which are formed according to FIG. 1, FIG. 3 or FIG. The injectors 10 each inject the fuel (diesel or gasoline) directly into combustion chambers 106.

Es sei noch darauf hingewiesen, dass die Begriffe "oben" und "unten" in der obigen Beschreibung sich ausschließlich auf die Figuren beziehen. Grundsätzlich kann die Vorrichtung 10 auch in einer anderen Lage als der in den Figuren dargestellten angeordnet werden.It should be noted that the terms "top" and "bottom" in the above description refer exclusively to the figures. In principle, the device 10 can also be arranged in a different position than that shown in the figures.

Claims (12)

  1. Fuel injection device (10) for internal combustion engines (94), in particular common-rail injector, with a housing (12) having an injection end (18), with a recess (20) running in the housing (12), with at least one axially movable valve element (24) which is arranged in the recess (20), cooperates with a valve seat and has a pressure surface (36) which faces away from the injection end (18) and delimits a control space (38) axially, with a sleeve part (40) which delimits the control space radially, and with at least one device (55) which loads the sleeve part (40) against a first housing portion (16) and loads the valve element (24) in the direction of the injection end (18), the device (55) comprising separate prestressing devices (46, 50), in each case one prestressing device (50) loading the valve element (24) and another prestressing device (46) loading the sleeve part (40), characterized in that the sleeve part (40) has a peripheral sharp edge (44) with which it bears against the first housing portion (16).
  2. Fuel injection device (10) according to Claim 1, characterized in that the prestressing device (46) which loads the sleeve part (40) is supported on a second and stationary housing portion (14).
  3. Fuel injection device (10) according to one of the preceding claims, characterized in that the prestressing device (46) which loads the sleeve part (40) is supported on a step (48) of the recess (20) in the housing (12).
  4. Fuel injection device (10) according to one of the preceding claims, characterized in that in the wall of the sleeve part (40) there is an orifice which forms an inrun flow throttle (62) for the control space (38).
  5. Fuel injection device (10) according to one of the preceding claims, characterized in that the prestressing device which loads the sleeve part (40) comprises a spring washer (46) with an orifice through which the valve element (24) extends.
  6. Fuel injection device (10) according to Claim 5, characterized in that there is at least one recess (74) in the spring washer (46) in the region of the radially outer edge.
  7. Fuel injection device (10) according to one of Claims 1 to 5, characterized in that the prestressing device which loads the sleeve part (40) comprises a spring sleeve (46).
  8. Fuel injection device (10) according to Claim 7, characterized in that there is at least one orifice (74) in the wall of the spring sleeve (46).
  9. Fuel injection device (10) according to Claim 7, characterized in that there is an inrun flow throttle (62) in the wall of the spring sleeve (46).
  10. Fuel injection device (10) according to one of Claims 1 to 4, characterized in that the prestressing device which loads the sleeve part (40) comprises a spring element (46) with a supporting portion (88) and with at least two axially running spring portions (90).
  11. Fuel system (96) with a fuel tank (98), with at least one fuel injection device (10) which injects the fuel directly into the combustion space (106) of an internal combustion engine (94), with at least one high-pressure fuel pump (102), and with a fuel collecting line (104) to which the fuel injection device (10) is connected, characterized in that the fuel injection device (10) is designed according to one of Claims 1 to 10.
  12. Internal combustion engine (94) with at least one combustion space (106) into which the fuel is injected directly, characterized in that it has a fuel system (96) according to Claim 11.
EP02742681A 2001-05-08 2002-04-18 Fuel injection device for combustion motors, especially common rail injector, fuel system and internal combustion engine Expired - Lifetime EP1395744B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10122256 2001-05-08
DE10122256A DE10122256A1 (en) 2001-05-08 2001-05-08 Fuel injection device for internal combustion engines, in particular common rail injector, and fuel system and internal combustion engine
PCT/DE2002/001435 WO2002090756A1 (en) 2001-05-08 2002-04-18 Fuel injection device for combustion motors, especially common rail injector, fuel system and internal combustion engine

Publications (2)

Publication Number Publication Date
EP1395744A1 EP1395744A1 (en) 2004-03-10
EP1395744B1 true EP1395744B1 (en) 2006-04-05

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP02742681A Expired - Lifetime EP1395744B1 (en) 2001-05-08 2002-04-18 Fuel injection device for combustion motors, especially common rail injector, fuel system and internal combustion engine

Country Status (5)

Country Link
US (1) US6928985B2 (en)
EP (1) EP1395744B1 (en)
JP (1) JP4130777B2 (en)
DE (2) DE10122256A1 (en)
WO (1) WO2002090756A1 (en)

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DE10351460A1 (en) 2003-11-04 2005-06-09 Robert Bosch Gmbh Fuel injection device, and method for its production
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DE102005020360A1 (en) * 2005-05-02 2006-11-09 Robert Bosch Gmbh Valve for controlling an injection valve of an internal combustion engine
DE102006009659A1 (en) * 2005-07-25 2007-02-01 Robert Bosch Gmbh Fuel injection device for internal combustion engine, has valve unit arranged in housing and composed of several parts including control piston and nozzle needle, where piston and needle are coupled to each other via hydraulic coupler
DE102007001549A1 (en) * 2007-01-10 2008-07-17 Robert Bosch Gmbh Dehnhülsenbefestigung
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Also Published As

Publication number Publication date
DE50206317D1 (en) 2006-05-18
US6928985B2 (en) 2005-08-16
JP2004519599A (en) 2004-07-02
DE10122256A1 (en) 2002-11-21
EP1395744A1 (en) 2004-03-10
WO2002090756A1 (en) 2002-11-14
JP4130777B2 (en) 2008-08-06
US20040025842A1 (en) 2004-02-12

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