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EP0977942A1 - Fuel injection valve for internal combustion engines - Google Patents

Fuel injection valve for internal combustion engines

Info

Publication number
EP0977942A1
EP0977942A1 EP98936193A EP98936193A EP0977942A1 EP 0977942 A1 EP0977942 A1 EP 0977942A1 EP 98936193 A EP98936193 A EP 98936193A EP 98936193 A EP98936193 A EP 98936193A EP 0977942 A1 EP0977942 A1 EP 0977942A1
Authority
EP
European Patent Office
Prior art keywords
valve
chamber
spring
fuel injection
valve member
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP98936193A
Other languages
German (de)
French (fr)
Inventor
Wolfgang Ripper
Werner Wagner
Bernd Dittus
Manfred Mack
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP0977942A1 publication Critical patent/EP0977942A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M45/00—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship
    • F02M45/12—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship providing a continuous cyclic delivery with variable 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
    • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
    • F02M61/20—Closing valves mechanically, e.g. arrangements of springs or weights or permanent magnets; Damping of valve lift
    • F02M61/205—Means specially adapted for varying the spring tension or assisting the spring force to close the injection-valve, e.g. with damping of valve lift
    • 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
    • F02M2200/30—Fuel-injection apparatus having mechanical parts, the movement of which is damped
    • F02M2200/304—Fuel-injection apparatus having mechanical parts, the movement of which is damped using hydraulic means

Definitions

  • the invention is based on a fuel injection valve for internal combustion engines according to the preamble of claim 1.
  • a piston-shaped valve member is guided axially displaceably in a guide bore of a valve body.
  • the valve member has at its combustion chamber end a sealing surface with which it interacts to control an injection opening with a valve seat surface arranged on the valve body. With its end facing away from the combustion chamber, the valve member projects into a spring chamber in which at least one valve spring is arranged, which acts on the valve member in the closing direction towards the valve seat surface.
  • the valve member also has a pressure shoulder projecting into a pressure chamber that can be filled with high-pressure fuel, which is designed such that the high-pressure fuel acting on the pressure shoulder acts on the valve member in the opening direction against the restoring force of the valve springs.
  • the known fuel injection valve In order to generate a two-stage opening stroke curve on the known fuel injection valve, it has two valve springs arranged axially one behind the other become effective one after the other during the opening stroke course of the valve member and thus produce a stepped opening of the opening cross section on the injection valve. Furthermore, a damping space delimited by the valve member is provided on the known injection valve, which can be controlled during the opening stroke movement of the valve member in such a way that the pressure built up in it counteracts the opening stroke movement of the valve member during its remaining stroke in order to be able to carry out a two-stage injection curve even at high speeds and full load.
  • the known fuel injection valve has the disadvantage that it is very large due to the necessary two valve springs and the additional damping space and requires a large installation space, which is often not available in modern internal combustion engines. Furthermore, the production of the known fuel injection valve is relatively complex and therefore expensive.
  • the fuel injection valve for internal combustion engines according to the invention with the characterizing features of claim 1 has the advantage that the spring chamber itself is used as a hydraulic damper. This is made possible in a structurally simple manner by not removing the quantity of leakage oil from the spring chamber, as a result of which the pressure chamber filled with fuel acts as a hydraulic working chamber which applies an additional closing force to the valve member.
  • the hydraulic closing force of the damping chamber acts differently depending on the operating state of the internal combustion engine, ie speed, load and temperature.
  • the degree of damping or the closing force can be achieved by the play between the valve member and the guide bore wall guiding it as well as the size of the damping volume of the spring chamber.
  • the closing stroke movement of the valve member can also be influenced, the closing pressure in the spring chamber increasing with increasing load and speed also causing the valve member to close more quickly at the end of the injection.
  • Such a rapid closing of the valve member avoids the back-blowing of combustion gases into the injection valve and thus damage to the sealing seat.
  • the load-dependent and speed-dependent hydraulic closing pressure in the spring chamber thus permits a low opening pressure of the fuel injection valve, which together with the valve member stroke damping reduces the ignition delay during injection at the internal combustion engine and thus reduces the
  • valve member stroke damping is increased by the viscosity of the fuel and thus compensates for the increased combustion noise of the diesel internal combustion engine in this operating state.
  • the highest closing pressure is present in the spring chamber and prevents the combustion gases from blowing back by quickly closing the valve member.
  • FIG. 1 shows an exemplary embodiment of the fuel injection valve in a longitudinal section.
  • the fuel injection valve for internal combustion engines shown in FIG. 1 has a valve body 1 which, together with an intermediate disk 3 resting on its end facing away from the combustion chamber, is clamped to a valve holding body 7 by means of a union nut 5.
  • the valve body 1 projecting with its end facing away from the intermediate disk 3 into a combustion chamber (not shown) of an internal combustion engine has a guide bore 9 in which a piston-shaped valve member 11 is axially displaceably guided, which has a conical sealing surface 13 on one end face with which it is connected a valve seat 15 cooperating by reducing the diameter of the guide bore 9.
  • This valve seat 15 is arranged at the closed end of the valve body 1 on the combustion chamber side and adjoins the injection openings 17 provided at the end of the guide bore 9, which adjoin the valve seat 15 downstream in the injection direction.
  • the guide bore 9 of the valve member 11 is expanded at one point to a pressure chamber 19, in the area of which the valve member 11 has a pressure shoulder 21 and which is connected via an inlet channel 23 to a connecting piece 25 on the valve holding body 7 to which a fuel delivery line, not shown is connected by a high pressure fuel pump.
  • the pressure chamber 19 is in a known manner with an annular gap between the shaft of the valve member 11 and the wall of the guide bore 9 the valve seat 15 and the injection openings 17 connected.
  • valve member 11 With its end facing away from the combustion chamber, the valve member 11 projects into a spring plate 27 which, penetrating the washer 3, extends into a spring chamber 29 in the valve holding body 7.
  • a valve spring 31 is clamped, which rests with its lower end facing the combustion chamber on the spring plate 27 and which is supported with its upper end in a stationary manner on the upper end wall of the spring chamber 29 in the valve holding body 7.
  • an adjusting disk 33 is provided between the upper spring chamber wall and the upper end of the valve spring 31 in order to adjust the spring preload force.
  • an opening bore 35 is provided in the valve holding body 7, which opens into the spring chamber 29 from the outside.
  • a screw plug 37 is screwed into this opening bore 35, a sealing washer 39 being clamped between the housing and screw plug 37.
  • the hydraulic filling volume of the spring chamber 29 can be changed via the thickness of the sealing disk 39 or the screwing depth of the screw plug 37.
  • the valve member 11 and the spring plate 27 have a play on the wall of the guide bore 9 or the intermediate disk 3, which form a throttle gap between the pressure chamber 19 and the spring chamber 29, through which a throttled overflow of fuel occurs the pressure chamber 19 in the spring chamber 29 is possible.
  • This throttled overflow cross section can also be formed by longitudinal recesses on the valve member 11 in order to provide sufficient guide surfaces for a reliable axial guidance of the valve member 11.
  • the fuel injection valve for internal combustion engines works in the following manner. Before the start of high-pressure fuel injection, the pressure chamber 19 and, via this, also the spring chamber 29 are filled with fuel, whose pressure corresponds to the stand pressure in the high pressure supply system. The valve member 11 is held in contact with the valve seat 15 by the closing force of the valve spring 31. At the start of the high-pressure fuel injection, fuel under high pressure passes from the high-pressure fuel pump via the inlet channel 23 into the pressure chamber 19 and acts on the valve member 11 on the pressure shoulder 21 in the opening stroke direction. If the opening force acting on the pressure shoulder 21 exceeds the closing force of the valve spring 31, the valve member 11 in
  • Opening stroke direction shifted from valve seat 15. The injection cross section between the sealing surface 13 and the valve seat 15 is opened, so that the fuel under pressure at the valve seat 15 passes through the injection openings 17 for injection into the combustion chamber of the internal combustion engine.
  • the enclosed in the spring chamber 29 Kraf material volume acts as a hydraulic damper of the opening stroke movement of the valve member 11, so that the opening stroke movement of the valve member 11 is initially delayed. In this way, only a relatively small opening cross-section is initially opened at the beginning of high-pressure fuel injection, so that only a small amount of pre-injection reaches the combustion chamber of the internal combustion engine and causes a slight ignition delay there.
  • the spring chamber 29, which acts as a hydraulic working chamber, has a different effect depending on the speed or load, depending on the operating state of the internal combustion engine, with increasing closing pressures in the spring chamber 29 being achieved with increasing load and increasing speed.
  • the strength of the damping of the opening stroke movement of the valve member 11 can also be adjusted and optimized by the throttle gap dimension between the pressure chamber 19 and the spring chamber 29 and by the size of the hydraulic damping volume in the spring chamber 29.

Landscapes

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

Abstract

The invention relates to a fuel injection valve for internal combustion engines, comprising a valve member (11) that can be displaced in the axial direction in a valve body (1). Said valve member cooperates with a valve seat surface (15) on the valve body (1) and with a tight surface (13) to control an injection orifice (17). The end of said member facing away from the combustion chamber is impinged upon by a valve spring (31) arranged in a spring chamber (29) in the closed position. The valve member (11) has a pressure shoulder (21) working in the opened direction, which projects into a pressure chamber (19) that can be filled with high pressure fuel. The spring chamber (19) is connected to the pressure chamber (19) through a choke gap and is closed in relation to a fuel return system so that the spring chamber (29) acts as a hydraulic damper when the valve member (11) lifts to the opened position.

Description

Kraf stoffeinspritzventil für BrennkraftmaschinenFuel injection valve for internal combustion engines
Stand der TechnikState of the art
Die Erfindung geht von einem Kraftstoffeinspritzventil für Brennkraftmaschinen nach der Gattung des Patentanspruchs 1 aus. Bei einem derartigen aus der DE 44 40 182 AI bekannten Kraftstoffeinspritzventil ist ein kolbenförmiges Ventilglied in einer Führungsbohrung eines Ventilkörpers axial verschiebbar geführt. Das Ventilglied weist dabei an seinem brennraumseitigen Ende eine Dichtfläche auf, mit der es zur Steuerung einer Einspritzöffnung mit einer am Ventilkörper angeordneten Ventilsitzflache zusammenwirkt. Mit seinem brennraumabgewandten Ende ragt das Ventilglied in einen Federraum, in dem wenigstens eine Ventilfeder angeordnet ist, die das Ventilglied in Schließrichtung zur Ventilsitz- flache hin beaufschlagt. Das Ventilglied weist weiterhin eine in einen mit Kraftstoffhochdruck befüllbaren Druckraum ragende Druckschulter auf, die dabei so ausgebildet ist, daß der an der Druckschulter angreifende Kraftstoffhochdruck das Ventilglied in Öffnungsrichtung entgegen der Rückstellkraft der Ventilfedern beaufschlagt.The invention is based on a fuel injection valve for internal combustion engines according to the preamble of claim 1. In such a fuel injection valve known from DE 44 40 182 AI, a piston-shaped valve member is guided axially displaceably in a guide bore of a valve body. The valve member has at its combustion chamber end a sealing surface with which it interacts to control an injection opening with a valve seat surface arranged on the valve body. With its end facing away from the combustion chamber, the valve member projects into a spring chamber in which at least one valve spring is arranged, which acts on the valve member in the closing direction towards the valve seat surface. The valve member also has a pressure shoulder projecting into a pressure chamber that can be filled with high-pressure fuel, which is designed such that the high-pressure fuel acting on the pressure shoulder acts on the valve member in the opening direction against the restoring force of the valve springs.
Um dabei einen zweistufigen Öffnungshubverlauf am bekannten Kraftstoffeinspritzventil zu erzeugen, weist dieses zwei axial hintereinander angeordnete Ventilfedern auf, die während des Offnungshubverlaufes des Ventilgliedes nacheinander wirksam werden und somit ein stufenförmiges Aufsteuern des Öffnungsquerschnittes am Einspritzventil erzeugen. Des weiteren ist ein vom Ventilglied begrenzter Dämpfungsraum am bekannten Einspritzventil vorgesehen, der während der Öffnungshubbewegung des Ventilgliedes derart zusteuerbar ist, daß der darin aufgebaute Druck der Öffnungshubbewegung des Ventilgliedes während dessen Resthub entgegenwirkt um auch bei hohen Drehzahlen und Vollast eine zweistufige Einspritzverlaufsformung vornehmen zu können.In order to generate a two-stage opening stroke curve on the known fuel injection valve, it has two valve springs arranged axially one behind the other become effective one after the other during the opening stroke course of the valve member and thus produce a stepped opening of the opening cross section on the injection valve. Furthermore, a damping space delimited by the valve member is provided on the known injection valve, which can be controlled during the opening stroke movement of the valve member in such a way that the pressure built up in it counteracts the opening stroke movement of the valve member during its remaining stroke in order to be able to carry out a two-stage injection curve even at high speeds and full load.
Dabei weist das bekannte Kraftstoffeinspritzventil jedoch den Nachteil auf, daß es aufgrund der notwendigen zwei Ventilfedern und des zusätzlichen Dämpfungsraumes sehr groß baut und einen hohen Einbauraum benötigt, der an modernen Brennkraftmaschinen häufig nicht zur Verfügung steht. Des weiteren ist die Fertigung des bekannten Kraftstoffein- spritzventils relativ aufwendig und somit kostenintensiv.However, the known fuel injection valve has the disadvantage that it is very large due to the necessary two valve springs and the additional damping space and requires a large installation space, which is often not available in modern internal combustion engines. Furthermore, the production of the known fuel injection valve is relatively complex and therefore expensive.
Vorteile der ErfindungAdvantages of the invention
Das erfindungsgemäße Kraftstoffeinspritzventil für Brennkraftmaschinen mit den kennzeichnenden Merkmalen des Patentanspruchs 1 hat demgegenüber den Vorteil, daß der Federraum selbst als hydraulischer Dämpfer genutzt wird. Dies wird dabei in konstruktiv einfacher Weise durch das Nichtabführen der Leckölmenge aus dem Federraum möglich, wodurch der mit Kraftstoff gefüllte Druckraum als hydraulischer Arbeitsraum wirkt, der eine zusätzliche Schließkraft auf das Ventilglied aufbringt. Die hydraulische Schließkraft des Dämpfungsräumes wirkt dabei je nach Betriebszustand der Brennkraftmaschine, d.h. Drehzahl, Last und Temperatur unterschiedlich. Der Dämpfungsgrad bzw. die Schließkraft kann dabei durch das Spiel zwischen dem Ventilglied und der dieses führenden Führungsbohrungswand sowie der Größe des Dämpfungsvolumens des Federraumes eingestellt werden. Dabei kann neben einer Öffnungsverlaufsformung auch die Schließhubbewegung des Ventilgliedes beeinflußt werden, wobei der mit steigender Last und Drehzahl steigende Schließdruck im Federraum auch ein schnelleres Schließen des Ventilgliedes am Ende der Einspritzung bewirkt. Ein derartiges schnelles Schließen des Ventilgliedes vermeidet dabei ein Rückblasen von Verbrennungsgasen in das Einspritzventil und somit eine Beschädigung des Dichtsitzes. Der last- und drehzahlabhängige hydraulische Schließdruck im Federraum erlaubt somit einen niedrigen Öffnungsdruck des Kraftstoffeinspritz - ventils, der gemeinsam mit der Ventilgliedhubdampfung eine Reduzierung des Zündverzuges während der Einspritzung an der Brennkraftmaschine und somit eine Verringerung desThe fuel injection valve for internal combustion engines according to the invention with the characterizing features of claim 1 has the advantage that the spring chamber itself is used as a hydraulic damper. This is made possible in a structurally simple manner by not removing the quantity of leakage oil from the spring chamber, as a result of which the pressure chamber filled with fuel acts as a hydraulic working chamber which applies an additional closing force to the valve member. The hydraulic closing force of the damping chamber acts differently depending on the operating state of the internal combustion engine, ie speed, load and temperature. The degree of damping or the closing force can be achieved by the play between the valve member and the guide bore wall guiding it as well as the size of the damping volume of the spring chamber. In addition to shaping the course of the opening, the closing stroke movement of the valve member can also be influenced, the closing pressure in the spring chamber increasing with increasing load and speed also causing the valve member to close more quickly at the end of the injection. Such a rapid closing of the valve member avoids the back-blowing of combustion gases into the injection valve and thus damage to the sealing seat. The load-dependent and speed-dependent hydraulic closing pressure in the spring chamber thus permits a low opening pressure of the fuel injection valve, which together with the valve member stroke damping reduces the ignition delay during injection at the internal combustion engine and thus reduces the
Verbrennungsgeräusches zur Folge hat . Beim Start der noch kalten Brennkraftmaschine verstärkt sich diese Wirkung der Ventilgliedhubdampfung durch die Viskosität des Kraftstoffes und kompensiert somit das erhöhte Verbrennungsgeräusch der Dieselbrennkraftmaschine in diesem Betriebszustand. Bei Erreichen des Nenndrehzahlbereiches liegt der höchste Schließdruck im Federraum vor und verhindert durch das schnelle Schließen des Ventilgliedes das Rückblasen von Verbrennungsgasen .Combustion noise. At the start of the still cold internal combustion engine, this effect of valve member stroke damping is increased by the viscosity of the fuel and thus compensates for the increased combustion noise of the diesel internal combustion engine in this operating state. When the nominal speed range is reached, the highest closing pressure is present in the spring chamber and prevents the combustion gases from blowing back by quickly closing the valve member.
Mit dem erfindungsgemäßen Kraftstoffeinspritzventil ist es somit möglich in konstruktiv einfacher Weise eine geräuschmindernde Einspritzverlaufsfor ung am Kraftstoffeinspritz - venti1 vorzunehmen .With the fuel injection valve according to the invention, it is thus possible in a structurally simple manner to carry out a noise-reducing injection progression on the fuel injection valve 1.
Weitere Vorteile und vorteilhafte Ausgestaltungen des Gegenstandes der Erfindung sind der Beschreibung, der Zeichnung und den Patentansprüchen entnehmbar.Further advantages and advantageous configurations of the subject matter of the invention can be gathered from the description, the drawing and the patent claims.
Zeichnung Ein Ausführungsbeispiel des erfindungsgemäßen Kraftstoffeinspritzventils für Brennkraftmaschinen ist in der Zeichnung dargestellt und wird in der folgenden Beschreibung näher erläutert. Es zeigt die Figur 1 ein Ausführungsbei- spiel des Kraftstoffeinspritzventils in einem Längsschnitt.drawing An embodiment of the fuel injection valve for internal combustion engines according to the invention is shown in the drawing and is explained in more detail in the following description. FIG. 1 shows an exemplary embodiment of the fuel injection valve in a longitudinal section.
Beschreibung des AusführungsbeispielsDescription of the embodiment
Das in der Figur 1 dargestellte Kraftstoffeinspritzventil für Brennkraftmaschinen weist einen Ventilkörper 1 auf, der zusammen mit einer an seiner brennraumabgewandten Stirnseite anliegenden Zwischenscheibe 3 mittels einer Überwurfmutter 5 an einem Ventilhaltekörper 7 festgespannt ist. Der mit seinem der Zwischenscheibe 3 abgewandten Ende in einen nicht dargestellten Brennraum einer Brennkraftmaschine ragende Ventilkörper 1 weist eine Führungsbohrung 9 auf, in der ein kolbenförmiges Ventilglied 11 axial verschiebbar geführt ist, das an seiner einen Stirnseite eine konische Dichtfläche 13 aufweist, mit der es mit einem durch eine Verringerung des Durchmessers der Führungsbohrung 9 gebildeten Ventilsitz 15 zusammenwirkt. Dieser Ventilsitz 15 ist dabei am geschlossenen brennraumseitigen Ende des Ventilkörpers 1 angeordnet und grenzt an am Ende der Führungsbohrung 9 vorgesehene Einspritzöffnungen 17, die sich stromabwärts in Einspritzrichtung an den Ventilsitz 15 anschließen. Die Führungsbohrung 9 des Ventilgliedes 11 ist an einer Stelle zu einem Druckraum 19 erweitert, in dessen Bereich das Ventilglied 11 eine Druckschulter 21 aufweist und der über einen Zulaufkanal 23 mit einem Anschlußstutzen 25 am Ventilhaltekörper 7 verbunden ist, an den eine nicht dargestellte Kraftstoff-Förderleitung von einer Kraftstoffhochdruckpumpe angeschlossen ist. Der Druckraum 19 ist dabei in bekannter Weise über einen Ringspalt zwischen dem Schaft des Ventilgliedes 11 und der Wand der Führungsbohrung 9 mit der Ventilsitzfläche 15 bzw. den Einspritzöffnungen 17 verbunden. Mit seinem brennraumabgewandten Ende ragt das Ventilglied 11 in einen Federteller 27, der sich, die Zwischenscheibe 3 durchdringend, bis in einen Federraum 29 im Ventilhaltekörper 7 erstreckt. In diesem Federraum 29 ist eine Ventilfeder 31 eingespannt, die mit ihrem unteren brennraumzugewandten Ende am Federteller 27 anliegt und die sich mit ihrem oberen Ende ortsfest an der oberen Stirnwand des Federraumes 29 im Ventilhaltekörper 7 abstützt. Dabei ist zur Einstellung der Federvorspannkraft eine Einstell - scheibe 33 zwischen der oberen Federraumwand und dem oberen Ende der Ventilfeder 31 vorgesehen. Des weiteren ist eine Öffnungsbohrung 35 im Ventilhaltekörper 7 vorgesehen, die von außen in den Federraum 29 mündet. In diese Öffnungs- bohrung 35 ist eine Verschlußschraube 37 eingeschraubt, wobei zwischen Gehäuse und Verschlußschraube 37 eine Dichtscheibe 39 eingespannt ist. Dabei läßt sich über die Stärke der Dichtscheibe 39 bzw. die Einschraubtiefe der Verschlußschraube 37 das hydraulische Füllvolumen des Federraumes 29 verändern. Zur Befüllung des Federraumes 29 mit Kraftstoff weisen das Ventilglied 11 und der Federteller 27 ein Spiel zur Wand der Führungsbohrung 9 bzw. der Zwischenscheibe 3 auf, die einen Drosselspalt zwischen dem Druckraum 19 und dem Federraum 29 bilden, durch den ein gedrosseltes Überströmen von Kraftstoff aus dem Druckraum 19 in den Federraum 29 möglich ist. Dabei kann dieser gedrosselte Überströmquerschnitt auch durch Längsausnehmungen am Ventilglied 11 gebildet sein, um so ausreichend Führungs- flächen für eine sichere axiale Führung des Ventilgliedes 11 bereitzustellen.The fuel injection valve for internal combustion engines shown in FIG. 1 has a valve body 1 which, together with an intermediate disk 3 resting on its end facing away from the combustion chamber, is clamped to a valve holding body 7 by means of a union nut 5. The valve body 1 projecting with its end facing away from the intermediate disk 3 into a combustion chamber (not shown) of an internal combustion engine has a guide bore 9 in which a piston-shaped valve member 11 is axially displaceably guided, which has a conical sealing surface 13 on one end face with which it is connected a valve seat 15 cooperating by reducing the diameter of the guide bore 9. This valve seat 15 is arranged at the closed end of the valve body 1 on the combustion chamber side and adjoins the injection openings 17 provided at the end of the guide bore 9, which adjoin the valve seat 15 downstream in the injection direction. The guide bore 9 of the valve member 11 is expanded at one point to a pressure chamber 19, in the area of which the valve member 11 has a pressure shoulder 21 and which is connected via an inlet channel 23 to a connecting piece 25 on the valve holding body 7 to which a fuel delivery line, not shown is connected by a high pressure fuel pump. The pressure chamber 19 is in a known manner with an annular gap between the shaft of the valve member 11 and the wall of the guide bore 9 the valve seat 15 and the injection openings 17 connected. With its end facing away from the combustion chamber, the valve member 11 projects into a spring plate 27 which, penetrating the washer 3, extends into a spring chamber 29 in the valve holding body 7. In this spring chamber 29, a valve spring 31 is clamped, which rests with its lower end facing the combustion chamber on the spring plate 27 and which is supported with its upper end in a stationary manner on the upper end wall of the spring chamber 29 in the valve holding body 7. In this case, an adjusting disk 33 is provided between the upper spring chamber wall and the upper end of the valve spring 31 in order to adjust the spring preload force. Furthermore, an opening bore 35 is provided in the valve holding body 7, which opens into the spring chamber 29 from the outside. A screw plug 37 is screwed into this opening bore 35, a sealing washer 39 being clamped between the housing and screw plug 37. The hydraulic filling volume of the spring chamber 29 can be changed via the thickness of the sealing disk 39 or the screwing depth of the screw plug 37. To fill the spring chamber 29 with fuel, the valve member 11 and the spring plate 27 have a play on the wall of the guide bore 9 or the intermediate disk 3, which form a throttle gap between the pressure chamber 19 and the spring chamber 29, through which a throttled overflow of fuel occurs the pressure chamber 19 in the spring chamber 29 is possible. This throttled overflow cross section can also be formed by longitudinal recesses on the valve member 11 in order to provide sufficient guide surfaces for a reliable axial guidance of the valve member 11.
Das erfindungsgemäße Kraftstoffeinspritzventil für Brennkraftmaschinen arbeitet in folgender Weise. Vor Beginn der Kraftstoffhochdruckeinspritzung ist der Druckraum 19 und über diesen auch der Federraum 29 mit Kraftstoff gefüllt, dessen Druck dem Standdruck im Hochdruckzuleitungssystem entspricht. Dabei wird das Ventilglied 11 von der Schließkraft der Ventilfeder 31 in Anlage am Ventilsitz 15 gehalten. Mit Beginn der Kraftstoffhochdruckeinspritzung gelangt unter hohem Druck stehender Kraftstoff von der Kraftstoffhochdruckpumpe über den Zulaufkanal 23 in den Druckraum 19 und beaufschlagt dort das Ventilglied 11 an der Druckschulter 21 in Öffnungshubrichtung. Übersteigt die an der Druckschulter 21 angreifende Öffnungskraft die Schließ- kraft der Ventilfeder 31 wird das Ventilglied 11 inThe fuel injection valve for internal combustion engines works in the following manner. Before the start of high-pressure fuel injection, the pressure chamber 19 and, via this, also the spring chamber 29 are filled with fuel, whose pressure corresponds to the stand pressure in the high pressure supply system. The valve member 11 is held in contact with the valve seat 15 by the closing force of the valve spring 31. At the start of the high-pressure fuel injection, fuel under high pressure passes from the high-pressure fuel pump via the inlet channel 23 into the pressure chamber 19 and acts on the valve member 11 on the pressure shoulder 21 in the opening stroke direction. If the opening force acting on the pressure shoulder 21 exceeds the closing force of the valve spring 31, the valve member 11 in
Öffnungshubrichtung vom Ventilsitz 15 verschoben. Dabei wird der Einspritzquerschnitt zwischen der Dichtfläche 13 und dem Ventilsitz 15 aufgesteuert , so daß der am Ventilsitz 15 anstehende, unter hohem Druck stehende Kraftstoff durch die Einspritzöffnungen 17 zur Einspritzung in den Brennraum der Brennkraftmaschine gelangt. Dabei wirkt das im Federraum 29 eingeschlossene Kraf stoffvolumen als hydraulischer Dämpfer der Öffnungshubbewegung des Ventilgliedes 11 entgegen, so daß die Öffnungshubbewegung des Ventilgliedes 11 zunächst verzögert wird. Auf diese Weise wird am Beginn der Kraft- stoffhochdruckeinspritzung zunächst nur ein relativ kleiner Öffnungsquerschnitt aufgesteuert , so daß nur eine geringe Voreinspritzmenge in den Brennraum der Brennkraftmaschine gelangt und dort einen geringen Zündverzug bewirkt . Nach dem weiteren Anstieg des Druckes im Druckraum 19 wird diese hydraulische Dämpfungskraft im Federraum 29 und die Schließkraft der Ventilfeder 31 weiter überstiegen, so daß die sich nunmehr anschließende Öffnungshubbewegung des Ventilgliedes 11 rasch durchlaufen werden kann. Dabei erhöht sich der hydraulische Druck im Federraum 29 weiter durch das vom Federteller 27 verdrängte Volumen. Am Ende der Hochdruckeinspritzung bricht der Kraftstoffhochdruck im Druckraum 19 zusammen und unterschreitet die Schließkraft des Ventilgliedes 11, die sich aus der Summe der Schließkraft der Ventilfeder 31 und der hydraulischen Druckkraft im Federraum 29 zusammensetzt. Dabei bewirkt diese verstärkte Schließkraft am Ventilglied 11 ein sehr rasches Zurückverschieben des Ventilgliedes 11 auf den Ventilsitz 15, so daß ein rasches Schließen des Kraftstoffeinspritzventils gewährleistet ist.Opening stroke direction shifted from valve seat 15. The injection cross section between the sealing surface 13 and the valve seat 15 is opened, so that the fuel under pressure at the valve seat 15 passes through the injection openings 17 for injection into the combustion chamber of the internal combustion engine. The enclosed in the spring chamber 29 Kraf material volume acts as a hydraulic damper of the opening stroke movement of the valve member 11, so that the opening stroke movement of the valve member 11 is initially delayed. In this way, only a relatively small opening cross-section is initially opened at the beginning of high-pressure fuel injection, so that only a small amount of pre-injection reaches the combustion chamber of the internal combustion engine and causes a slight ignition delay there. After the pressure in the pressure chamber 19 has risen further, this hydraulic damping force in the spring chamber 29 and the closing force of the valve spring 31 are further exceeded, so that the opening stroke movement of the valve member 11 which then follows can be carried out quickly. The hydraulic pressure in the spring chamber 29 increases further due to the volume displaced by the spring plate 27. At the end of the high-pressure injection, the high fuel pressure in the pressure chamber 19 collapses and falls below the closing force of the valve member 11, which results from the sum of the closing force of the valve spring 31 and the hydraulic pressure force in the Spring chamber 29 is composed. This increased closing force on the valve member 11 causes the valve member 11 to be pushed back very quickly onto the valve seat 15, so that a rapid closing of the fuel injection valve is ensured.
Der als hydraulischer Arbeitsraum wirkende Federraum 29 hat dabei je nach Betriebszustand der Brennkraftmaschine drehzahl- bzw. lastabhängig eine unterschiedliche Wirkung, wobei mit steigender Last und steigender Drehzahl steigende Schließdrücke im Federraum 29 erreicht werden. Die Stärke der Dämpfung der Öffnungshubbewegung des Ventilgliedes 11 kann zudem durch das Drosselspaltmaß zwischen dem Druckraum 19 und dem Federraum 29 sowie durch die Größe des hydrau- lischen Dämpfungsvolumens im Federraum 29 eingestellt und optimiert werden. The spring chamber 29, which acts as a hydraulic working chamber, has a different effect depending on the speed or load, depending on the operating state of the internal combustion engine, with increasing closing pressures in the spring chamber 29 being achieved with increasing load and increasing speed. The strength of the damping of the opening stroke movement of the valve member 11 can also be adjusted and optimized by the throttle gap dimension between the pressure chamber 19 and the spring chamber 29 and by the size of the hydraulic damping volume in the spring chamber 29.

Claims

Ansprüche Expectations
1. Kraftstoffeinspritzventil für Brennkraftmaschinen mit einem in einem Ventilkörper (1) axial verschiebbaren Ventilglied (11) , das mit einer an seinem brennraumseitigen Ende vorgesehenen Dichtfläche (13) zur Steuerung einer Einspritzöffnung (17) mit einer am Ventilkörper (1) angeordneten Ventilsitzfläche (15) zusammenwirkt und dessen brennraumabgewandtes Ende von einer in einem Federraum (29) angeordneten Ventilfeder (31) in Schließrichtung zur Ventilsitzfläche (15) hin beaufschlagt ist, wobei das Ventilglied eine in Öffnungsrichtung wirkende Druckschulter (21) aufweist, die in einen mit Kraftstoffhochdruck befüllbaren Druckraum (19) ragt, dadurch gekennzeichnet, daß der Federraum (29) über einen Drosselquerschnitt mit dem Druckraum (19) verbunden und gegenüber einem Kraftstoff- rücklaufSystem verschlossen ist.1. Fuel injection valve for internal combustion engines with a valve member (11) which is axially displaceable in a valve body (1) and which has a sealing surface (13) on its combustion chamber end for controlling an injection opening (17) with a valve seat surface (15) arranged on the valve body (1) ) cooperates and the end facing away from the combustion chamber is acted upon by a valve spring (31) arranged in a spring chamber (29) in the closing direction towards the valve seat surface (15), the valve member having a pressure shoulder (21) which acts in the opening direction and which flows into a pressure chamber which can be filled with high fuel pressure (19) protrudes, characterized in that the spring chamber (29) is connected to the pressure chamber (19) via a throttle cross section and is closed off from a fuel return system.
2. Kraftstoffeinspritzventil nach Anspruch 1, dadurch gekennzeichnet, daß der Drosselquerschnitt zwischen dem Druckraum (19) und dem Federraum (29) als ringförmiger Drosselspalt zwischen dem Ventilglied (11) und einer Führungsbohrungswand (9) ausgebildet ist.2. Fuel injection valve according to claim 1, characterized in that the throttle cross section between the pressure chamber (19) and the spring chamber (29) is designed as an annular throttle gap between the valve member (11) and a guide bore wall (9).
3. Kraftstoffeinspritzventil nach Anspruch 1, dadurch gekennzeichnet, daß der Federraum (29) während der Öffnungsphase des Kraftstoffeinspritzventils als hydraulischer Arbeitsraum wirkt, der eine zusätzliche Schließkraft auf das Ventilglied (11) aufbringt.3. Fuel injection valve according to claim 1, characterized in that the spring chamber (29) during the opening phase of the fuel injection valve hydraulic working chamber acts, which exerts an additional closing force on the valve member (11).
4. Kraftstoffeinspritzventil nach Anspruch 1, dadurch gekennzeichnet, daß am brennraumabgewandten Ende des kolbenförmigen Ventilgliedes (11) ein Federteller (27) anliegt, der auf seiner ventilgliedabgewandten Seite von der Ventilfeder (31) beaufschlagt ist, wobei zwischen dem Federteller (27) und der diesem umgebenden Gehäusewand ein Durchströmquerschnitt vorgesehen ist.4. Fuel injection valve according to claim 1, characterized in that at the end of the piston-shaped valve member (11) facing away from the combustion chamber, a spring plate (27) bears, which is acted upon on its side facing away from the valve member by the valve spring (31), between the spring plate (27) and the a flow cross-section is provided in this surrounding housing wall.
5. Kraftstoffeinspritzventil nach Anspruch 1, dadurch gekennzeichnet, daß eine in den Federraum (29) mündende Öffnungsbohrung (35) vorgesehen ist, in die eine Verschluß- schraube (37) dichtend eingeschraubt ist, über deren Einschraubtiefe sich das hydraulische Volumen des Federraumes (29) einstellen läßt.5. Fuel injection valve according to claim 1, characterized in that an opening bore (35) opening into the spring chamber (29) is provided, into which a screw plug (37) is screwed in a sealing manner, via the screw-in depth of which the hydraulic volume of the spring chamber (29 ) can be set.
6. Kraftstoffeinspritzventil nach Anspruch 1, dadurch gekennzeichnet, daß zwischen der Ventilfeder (31) und einer gehäusefesten Anlagefläche eine Einstellscheibe (33) eingespannt ist. 6. Fuel injection valve according to claim 1, characterized in that an adjusting disc (33) is clamped between the valve spring (31) and a bearing surface fixed to the housing.
EP98936193A 1997-11-27 1998-06-17 Fuel injection valve for internal combustion engines Withdrawn EP0977942A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19752496A DE19752496A1 (en) 1997-11-27 1997-11-27 Fuel injection valve for internal combustion engines
DE19752496 1997-11-27
PCT/DE1998/001649 WO1999028616A1 (en) 1997-11-27 1998-06-17 Fuel injection valve for internal combustion engines

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EP0977942A1 true EP0977942A1 (en) 2000-02-09

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US (1) US6269795B1 (en)
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JP (1) JP2001509858A (en)
DE (1) DE19752496A1 (en)
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DE10112426A1 (en) * 2001-03-15 2002-09-19 Bosch Gmbh Robert Fuel injection valve has pressure chamber and spring chamber connected by throttling connection so that pressure in spring chamber after termination of injection cycle up to beginning of next cycle falls off to standing pressure
DE10115214A1 (en) * 2001-03-28 2002-10-10 Bosch Gmbh Robert High-pressure fuel system for internal combustion engines
DE10157411A1 (en) * 2001-11-23 2003-06-26 Bosch Gmbh Robert High pressure fuel injector
GB0209049D0 (en) * 2002-04-20 2002-05-29 Delphi Tech Inc Fuel injector
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US6269795B1 (en) 2001-08-07
WO1999028616A1 (en) 1999-06-10
DE19752496A1 (en) 1999-06-02
JP2001509858A (en) 2001-07-24

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