EP0923671B1 - Fuel injection valve - Google Patents

Fuel injection valve Download PDF

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Publication number
EP0923671B1
EP0923671B1 EP98924009A EP98924009A EP0923671B1 EP 0923671 B1 EP0923671 B1 EP 0923671B1 EP 98924009 A EP98924009 A EP 98924009A EP 98924009 A EP98924009 A EP 98924009A EP 0923671 B1 EP0923671 B1 EP 0923671B1
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EP
European Patent Office
Prior art keywords
pressure
area
fuel injection
fuel
piston
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Expired - Lifetime
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EP98924009A
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German (de)
French (fr)
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EP0923671A1 (en
Inventor
Rudolf Heinz
Roger Potschin
Friedrich Boecking
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Robert Bosch GmbH
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Robert Bosch GmbH
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Publication of EP0923671A1 publication Critical patent/EP0923671A1/en
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M47/00Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
    • F02M47/02Fuel-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
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M61/00Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/16Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
    • F02M61/20Closing valves mechanically, e.g. arrangements of springs or weights or permanent magnets; Damping of valve lift
    • F02M61/205Means specially adapted for varying the spring tension or assisting the spring force to close the injection-valve, e.g. with damping of valve lift
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M47/00Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
    • F02M47/02Fuel-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
    • F02M47/027Electrically actuated valves draining the chamber to release the closing pressure
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M2200/00Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/21Fuel-injection apparatus with piezoelectric or magnetostrictive elements
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02MSUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M2200/00Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/40Fuel-injection apparatus with fuel accumulators, e.g. a fuel injector having an integrated fuel accumulator

Definitions

  • the invention relates to a fuel injection valve the genus of claim 1.
  • fuel injection valve is the actuating part of the valve member in one piece with executed the same.
  • the valve member has as an actuating part a piston that has on one side its front side limits the control pressure chamber and his other side about a pressure shoulder in an im Diameter passes the smaller part, at the end of which Sealing surface is arranged, which is the injection opening controls.
  • the pressure shoulder is exposed to the pressure in the pressure room, who is constantly in with a high pressure fuel accumulator Connection is, which in turn via a throttle in constant Connection to the control pressure chamber is.
  • This one has a second outlet controlled by a piezo valve becomes. When this outlet is opened, the pressure in the Control pressure chamber to a relief pressure that causes that the forces in the opening direction, for example, about the shoulder on the valve member, the injector to open.
  • FIG. 1 In the figure is a fuel injector schematically shown that with a high-pressure fuel storage 1 Fuel is supplied.
  • a high pressure fuel pump 3 sucks 4 fuel from a fuel tank and delivers it with high fuel injection pressure into the High-pressure fuel storage.
  • the fuel gets from there via a pressure line 6 into a pressure chamber 7 of the fuel injection valve 8.
  • the pressure chamber 7 is upstream a fuel injection opening 9, which leads to the inside Pressure chamber 7 is limited by a valve seat 10 and their connection between the pressure chamber 7 and the combustion chamber 11 of an associated internal combustion engine through a sealing surface 12 is controlled, which at the end of a valve member 14th is provided.
  • the valve member has an actuating part 15 and a needle part 16 which is in a guide bore 17 of the Actuating part leaves the pressure chamber 7 free and at the end Sealing surface 12 carries.
  • this is conical formed according to a conical valve seat 10.
  • a pressure shoulder 18 is formed, the pressure in Pressure chamber 7 is exposed such that from its load an acting in the opening direction of the valve member 14 resulting force is formed.
  • the actuating part 15 projects into a hydraulic space 20 in the housing of the fuel injector and points there an annular shoulder 21 which has a compensating pressure surface forms.
  • the actuating part 15 leads with one part 15a with reduced diameter from the hydraulic pressure chamber back out and is in a in a control pressure room 23 leading guide bore 24 out. It ends there Actuating part 15 in an end face 26, the pressure in Control pressure chamber 23 is exposed.
  • the control pressure room has via a throttle 28 a permanent connection to the high-pressure fuel accumulator. Furthermore leads from the control pressure room 23 a relief channel 29, in which, if necessary, a second Throttle 30 is arranged and by a valve member 31st an electrically controlled valve 32 opened or can be closed.
  • valve member 31 If the valve member 31 is opened, so the pressure in the control pressure chamber is reduced to a relief pressure lowered because 29 more via the relief line Fuel flows out than can flow through the throttle 28. By lowering this pressure with the falling, in Closing direction due to this pressure on the valve member acting forces outweigh those via the pressure shoulder 18 hydraulic forces acting on the valve member Opening direction. This means that the valve member is opened and the injection via the injection opening starts. To end this injection process, the Valve member 31 brought back in the closing direction, which for The consequence of this is that fuel that flows quickly in increases the control chamber pressure back to the original value in the amount of Brings fuel pressure in the high-pressure fuel reservoir 1. This high pressure causes a predominant force in Closing direction of the valve member 15 and directs the closing process on.
  • the hydraulic can be better controlled Room 20 provided with the compensating pressure surface 21 on the Ring shoulder between the actuating parts 15 and 15a.
  • the hydraulic room is closed but can be moved become.
  • a piston 33 is provided, which in a the bore opening into the hydraulic space can be moved tightly is stored.
  • This piston is designed as a stepped piston with a larger diameter part 35, the first Piston surface 36 limits the hydraulic space 20 and with a part 37 of smaller diameter, the second Piston surface, its end face 38 in a reference pressure space 39 ranges, which in turn with a throttle 40 High-pressure fuel accumulator 1 is connected.
  • the piston 33 has a stop 41, which is the displacement of the piston hydraulic space 20 limited.
  • the Pressure in the hydraulic pressure chamber can be kept constant namely on one compared to the pressure in the reference pressure space or reduced pressure in the high-pressure fuel reservoir 1.
  • This pressure in connection with the compensation pressure area places an additional load on the valve member 14 in Closing direction that remains essentially constant and thus, as a constant factor, the Opening characteristic of the valve member determined.
  • the throttle 40 also plays one Role with which the rigidity of the hydraulic column of the hydraulic space 20 and the retroactive force on the Valve member 14 can also be adjusted.
  • This throttle correctable to a non-linear force increase in Forces acting on the valve member in the opening direction influence.

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

Description

Stand der TechnikState of the art

Die Erfindung geht von einem Kraftstoffeinspritzventil nach der Gattung des Patentanspruchs 1 aus. Bei einem solchen, durch die GB-PS 1 320 057 bekannten Kraftstoffeinspritzventil ist das Betätigungsteil des Ventilglieds einstückig mit dem selben ausgeführt. Das Ventilglied hat dabei als Betätigungsteil einen Kolben, der auf seiner einen Seite mit seiner Stirnseite den Steuerdruckraum begrenzt und auf seiner anderen Seite über eine Druckschulter in einen im Durchmesser kleineren Teil übergeht, an dessen Ende die Dichtfläche angeordnet ist, welche die Einspritzöffnung steuert. Die Druckschulter ist dem Druck im Druckraum ausgesetzt, der ständig mit einem Kraftstoffhochdruckspeicher in Verbindung ist, welcher wiederum über eine Drossel in ständiger Verbindung mit dem Steuerdruckraum ist. Dieser hat einen zweiten Auslaß, der von einem Piezoventil gesteuert wird. Bei Öffnung dieses Auslasses sinkt der Druck im Steuerdruckraum auf einen Entlastungsdruck ab, der bewirkt, daß die Kräfte in Öffnungsrichtung, die beispielsweise über die Schulter auf das Ventilglied wirken, das Einspritzventils öffnen. The invention relates to a fuel injection valve the genus of claim 1. With such a known from GB-PS 1 320 057 fuel injection valve is the actuating part of the valve member in one piece with executed the same. The valve member has as an actuating part a piston that has on one side its front side limits the control pressure chamber and his other side about a pressure shoulder in an im Diameter passes the smaller part, at the end of which Sealing surface is arranged, which is the injection opening controls. The pressure shoulder is exposed to the pressure in the pressure room, who is constantly in with a high pressure fuel accumulator Connection is, which in turn via a throttle in constant Connection to the control pressure chamber is. This one has a second outlet controlled by a piezo valve becomes. When this outlet is opened, the pressure in the Control pressure chamber to a relief pressure that causes that the forces in the opening direction, for example, about the shoulder on the valve member, the injector to open.

Bei einem Kraftstoffeinspritzventil dieser Art besteht der Nachteil, daß eine genaue Dosierung der Kraftstoffeinspritzmenge über Zeit und Hub des Kraftstoffeinspritzventilgliedes nicht möglich ist. Beim Öffnen der Einspritzventilnadel hebt diese mit ihrer Dichtfläche vom Ventilsitz ab und es kann in diesem Augenblick der im Druckraum herrschende hohe Kraftstoffdruck auch auf die Dichtfläche in Öffnungsrichtung wirken. Damit erfährt das Ventilglied eine zusätzliche Kraft in Öffnungsrichtung, die sich gravierend auf das dynamische Öffnungsverhalten des Ventilglieds auswirkt. Über den Hub erreicht dabei die Kraft, die in Öffnungsrichtung wirkt einen Grenzwert. Der Kraftverlauf folgt dabei etwa einer Exponentialkurve. Diese Eigenschaft erschwert die Dosierung von kleinen Kraftstoffeinspritzmengen, bei denen ein Wiederschließen des Ventilglieds vor Erreichen seiner Endstellung bzw. vor Erreichen der maximalen, in Öffnungsrichtung wirkenden Kraft erforderlich ist. Eine genaue Dosierung von Kraftstoffeinspritzmengen ist vorallem im Zwischenhubbereich erschwert.In a fuel injector of this type Disadvantage that an exact dosage of the fuel injection quantity over time and stroke of the fuel injection valve member not possible. When the injector needle opens, it lifts this with its sealing surface from the valve seat and it can be in at this moment the high fuel pressure prevailing in the pressure chamber also on the sealing surface in the opening direction Act. The valve member thus experiences an additional force in the opening direction, which seriously affects the dynamic Opening behavior of the valve member affects. About the hub reaches the force that acts in the opening direction a limit. The force curve follows approximately one Exponential curve. This property makes dosing difficult of small fuel injection quantities, where a Reclosing the valve member before reaching it End position or before reaching the maximum, in the opening direction acting force is required. An exact Metering of fuel injection quantities is especially important Intermediate stroke range difficult.

Vorteile der ErfindungAdvantages of the invention

Mit dem erfindungsgemäßen Kraftstoffeinspritzventil gemäß den Merkmalen des Kennzeichens ist es nun möglich, den Öffnungsvorgang des Ventilgliedes besser zu beherrschen, so daß eine genauere Dosierung von kleinen Kraftstoffeinspritzmengen möglich wird. Mit Hilfe des Kolbens und des vom Ventilglied einerseits und dem Kolben andererseits angeschlossenen hydraulischen Raums erhält man über die Ausgleichsdruckfläche am Ventilglied eine stabilisierende Kraft, die den Öffnungsvorgang des Kraftstoffeinspritzventilgliedes vergleichmäßigt. Bereits mit der ersten Öffnungsbewegung des Ventilglieds baut sich in dem hydraulischen Raum ein Druck auf, der sehr schnell auf einen Höchstwert ansteigt, dann aber konstant bleibt, da sich die Position des Kolbens ab einem bestimmten Druck verändern kann und damit das Volumen konstant bleibt. In vorteilhafter Weiterbildung der Erfindung ist der Kolben mit unterschiedlich großen Kolbenflächen ausgestattet, so daß der Ausgangsdruck in dem hydraulischen Raum gegenüber dem Referenzdruck untersetzt ist, wobei, wenn als Referenzdruck der Druck der Kraftstoffhochdruckquelle gewählt ist auf die Ausgleichsdruckfläche am Ventilglied ein um das Untersetzungsverhältnis kleinerer Druck in Schließrichtung wirkt. Auf diese Art und Weise kann eine Gegenkraft auf das Ventilglied ab einem bestimmten Druck im wesentlichen konstant gehalten werden.With the fuel injection valve according to the invention the characteristics of the license plate it is now possible to Mastering the opening process of the valve member better, so that more accurate dosing of small amounts of fuel becomes possible. With the help of the piston and the Valve member on the one hand and the piston connected on the other hydraulic space is obtained via the compensation pressure area a stabilizing one on the valve member Force that causes the opening of the fuel injector member uniform. Already with the first opening movement of the valve member builds up in the hydraulic Space a pressure on that very quickly to a maximum increases, but then remains constant as the position changes of the piston can change from a certain pressure and so that the volume remains constant. In advantageous Further development of the invention is different with the piston large piston surfaces so that the Outlet pressure in the hydraulic room opposite that Reference pressure is reduced, whereby if as reference pressure the pressure of the high-pressure fuel source is selected on the Compensating pressure area on the valve member around the reduction ratio Smaller pressure acts in the closing direction. In this way, a counterforce can be exerted on the valve member essentially constant from a certain pressure being held.

Weitere Vorteile sind den restlichen Ansprüchen in Verbindung mit der nachfolgenden Beschreibung eines Ausführungsbeispiels zu entnehmen.Further advantages are related to the remaining claims with the following description of an embodiment refer to.

Beschreibungdescription

In der Figur ist schematisch ein Kraftstoffeinspritzventil dargestellt, das von einem Kraftstoffhochdruckspeicher 1 mit Kraftstoff versorgt wird. Eine Kraftstoffhochdruckpumpe 3 saugt aus einem Kraftstoffvorratsbehälter 4 Kraftstoff an und fördert ihn mit hohem Kraftstoffeinspritzdruck in den Kraftstoffhochdruckspeicher. Von dort gelangt der Kraftstoff über eine Druckleitung 6 in einen Druckraum 7 des Kraftstoffeinspritzventils 8. Der Druckraum 7 liegt stromaufwärts einer Kraftstoffeinspritzöffnung 9, die zum Innern zum Druckraum 7 hin von einem Ventilsitz 10 begrenzt ist und deren Verbindung zwischen dem Druckraum 7 und dem Brennraum 11 einer zugehörigen Brennkraftmaschine durch eine Dichtfläche 12 gesteuert wird, die am Ende eines Ventilglieds 14 vorgesehen ist. Das Ventilglied hat ein Betätigungsteil 15 und ein Nadelteil 16, der in einer Führungsbohrung 17 des Betätigungsteiles den Druckraum 7 freiläßt und am Ende die Dichtfläche 12 trägt. Dies ist im vorliegenden Falle kegelförmig ausgebildet entsprechend einem kegelförmigen Ventilsitz 10. Zwischen dem Betätigungsteil 15 und dem Nadelteil 16 wird eine Druckschulter 18 gebildet, die dem Druck im Druckraum 7 ausgesetzt ist derart, daß aus ihrer Belastung eine in Öffnungsrichtung des Ventilglieds 14 wirkende resultierende Kraft gebildet wird.In the figure is a fuel injector schematically shown that with a high-pressure fuel storage 1 Fuel is supplied. A high pressure fuel pump 3 sucks 4 fuel from a fuel tank and delivers it with high fuel injection pressure into the High-pressure fuel storage. The fuel gets from there via a pressure line 6 into a pressure chamber 7 of the fuel injection valve 8. The pressure chamber 7 is upstream a fuel injection opening 9, which leads to the inside Pressure chamber 7 is limited by a valve seat 10 and their connection between the pressure chamber 7 and the combustion chamber 11 of an associated internal combustion engine through a sealing surface 12 is controlled, which at the end of a valve member 14th is provided. The valve member has an actuating part 15 and a needle part 16 which is in a guide bore 17 of the Actuating part leaves the pressure chamber 7 free and at the end Sealing surface 12 carries. In the present case, this is conical formed according to a conical valve seat 10. Between the operating part 15 and the needle part 16, a pressure shoulder 18 is formed, the pressure in Pressure chamber 7 is exposed such that from its load an acting in the opening direction of the valve member 14 resulting force is formed.

Der Betätigungsteil 15 ragt in einen hydraulischen Raum 20 im Gehäuse des Kraftstoffeinspritzventils und weist dort eine Ringschulter 21 auf, die eine Ausgleichsdruckfläche bildet. Dabei führt das Betätigungsteil 15 mit einem Teil 15a mit reduziertem Durchmesser aus dem hydraulischen Druckraum wieder hinaus und wird in einer in einen Steuerdruckraum 23 mündenden Führungsbohrung 24 geführt. Dort endet das Betätigungsteil 15 in einer Stirnseite 26, die dem Druck im Steuerdruckraum 23 ausgesetzt ist. Der Steuerdruckraum hat über eine Drossel 28 eine ständige Verbindung mit dem Kraftstoffhochdruckspeicher. Weiterhin führt vom Steuerdruckraum 23 ein Entlastungskanal 29 ab, in dem ggf. eine zweite Drossel 30 angeordnet ist und der durch ein Ventilglied 31 eines elektrisch gesteuerten Ventils 32 geöffnet oder geschlossen werden kann. Wird das Ventilglied 31 geöffnet, so wird der Druck im Steuerdruckraum auf einen Entlastungsdruck abgesenkt, da über die Entlastungsleitung 29 mehr Kraftstoff abströmt, als über die Drossel 28 zuströmen kann. Mit Absenkung dieses Druckes damit mit den sinkenden, in Schließrichtung aufgrund dieses Druckes auf das Ventilglied wirkenden Kräften überwiegen die über die Druckschulter 18 auf das Ventilglied einwirkenden hydraulischen Kräfte in Öffnungsrichtung. Dies bedeutet, daß das Ventilglied geöffnet wird und die Einspritzung über die Einspritzöffnung beginnt. Zur Beendigung dieses Einspritzvorganges wird das Ventilglied 31 wieder in Schließrichtung gebracht, was zur Folge hat, daß schnell nachströmender Kraftstoff den Steuerraumdruck wieder auf den ursprünglichen Wert in Höhe des Kraftstoffdruckes im Kraftstoffhochdruckspeicher 1 bringt. Dieser hohe Druck bewirkt eine überwiegende Kraft in Schließrichtung des Ventilglieds 15 und leitet den Schließvorgang ein.The actuating part 15 projects into a hydraulic space 20 in the housing of the fuel injector and points there an annular shoulder 21 which has a compensating pressure surface forms. The actuating part 15 leads with one part 15a with reduced diameter from the hydraulic pressure chamber back out and is in a in a control pressure room 23 leading guide bore 24 out. It ends there Actuating part 15 in an end face 26, the pressure in Control pressure chamber 23 is exposed. The control pressure room has via a throttle 28 a permanent connection to the high-pressure fuel accumulator. Furthermore leads from the control pressure room 23 a relief channel 29, in which, if necessary, a second Throttle 30 is arranged and by a valve member 31st an electrically controlled valve 32 opened or can be closed. If the valve member 31 is opened, so the pressure in the control pressure chamber is reduced to a relief pressure lowered because 29 more via the relief line Fuel flows out than can flow through the throttle 28. By lowering this pressure with the falling, in Closing direction due to this pressure on the valve member acting forces outweigh those via the pressure shoulder 18 hydraulic forces acting on the valve member Opening direction. This means that the valve member is opened and the injection via the injection opening starts. To end this injection process, the Valve member 31 brought back in the closing direction, which for The consequence of this is that fuel that flows quickly in increases the control chamber pressure back to the original value in the amount of Brings fuel pressure in the high-pressure fuel reservoir 1. This high pressure causes a predominant force in Closing direction of the valve member 15 and directs the closing process on.

Die Flächen der Stirnseite 26 und der Druckschulter 18 müssen so aufeinander abgestimmt sein, daß ein Öffnungsvorgang bzw. ein Schließvorgang schnell und sicher durchgeführt werden können. Zusätzlich muß dabei beachtet werden, daß mit dem Abheben der Ventilnadel von ihrem Ventilsitz 10 eine zusätzliche Fläche vom Hochdruck beaufschlagt wird, so daß zunehmend Kräfte bis zu einem Grenzwert auf das Ventilglied in Öffnungsrichtung wirken. Der Verlauf dieser Kräfte über den Hub des Ventilglieds bzw. über die Zeit ist nicht linear. Somit ist es erschwert, einen Öffnungsquerschnitt im Zwischenbereich des Ventilnadelhubes zu bestimmen und zu bewerten. Solche reduzierten Öffnungshübe der Ventilnadel sind insbesondere dann von Wichtigkeit, wenn kleinste Kraftstoffeinspritzmengen zur Einspritzung gelangen sollen. Dies ist z.B. dann erforderlich wenn zur Steuerung des Verbrennungsablaufes über das Kraftstoffeinspritzventil Voreinspritzmengen vor einer Haupteinspritzung in den Brennraum eingebracht werden sollen. Um die Bewegung des Ventilglieds besser zu beherrschen ist erfindungsgemäß der hydraulische Raum 20 vorgesehen mit der Ausgleichsdruckfläche 21 an der Ringschulter zwischen den Betätigungsteilen 15 und 15a. Der hydraulische Raum ist geschlossen, kann aber verschoben werden. Dazu ist ein Kolben 33 vorgesehen, der in einer in den hydraulischen Raum mündenden Bohrung dicht verschiebbar gelagert ist. Dieser Kolben ist als Stufenkolben ausgebildet mit einem im Durchmesser größeren Teil 35, dessen erste Kolbenfläche 36 den hydraulischen Raum 20 begrenzt und mit einem im Durchmesser kleineren Teil 37, dessen zweite Kolbenfläche, seine Stirnseite 38 in einem Referenzdruckraum 39 reicht, der über eine Drossel 40 wiederum mit dem Kraftstoffhochdruckspeicher 1 verbunden ist. Der Kolben 33 hat einen Anschlag 41, der die Verschiebung des Kolbens zum hydraulischen Raum 20 hin begrenzt.The surfaces of the end face 26 and the pressure shoulder 18 must be coordinated so that an opening process or a closing process is carried out quickly and safely can be. In addition, it must be noted that with lifting the valve needle from its valve seat 10 one additional area is acted upon by the high pressure, so that increasingly forces up to a limit on the valve member act in the opening direction. The course of these forces over the stroke of the valve member or over time is not linear. It is therefore difficult to have an opening cross section in the To determine and close the intermediate range of the valve needle stroke rate. Such reduced opening strokes of the valve needle are particularly important when the smallest fuel injection quantities to get to the injection. This is e.g. then necessary when controlling the combustion process via the fuel injection valve pre-injection quantities before a main injection into the combustion chamber should be introduced. To the movement of the valve member According to the invention, the hydraulic can be better controlled Room 20 provided with the compensating pressure surface 21 on the Ring shoulder between the actuating parts 15 and 15a. The hydraulic room is closed but can be moved become. For this purpose, a piston 33 is provided, which in a the bore opening into the hydraulic space can be moved tightly is stored. This piston is designed as a stepped piston with a larger diameter part 35, the first Piston surface 36 limits the hydraulic space 20 and with a part 37 of smaller diameter, the second Piston surface, its end face 38 in a reference pressure space 39 ranges, which in turn with a throttle 40 High-pressure fuel accumulator 1 is connected. The piston 33 has a stop 41, which is the displacement of the piston hydraulic space 20 limited.

Wird, wie bereits oben beschrieben, ein Öffnungsvorgang des Ventilglieds 14 eingeleitet, wird also das Ventilglied 31 geöffnet und der Steuerdruckraum 23 auf Entlastungsdruck entlastet, so wird sich das Ventilglied beginnen in Öffnungsrichtung zu bewegen. Dabei taucht jedoch der im Durchmesser größere Betätigungsteil 15 weiter in den hydraulischen Raum 20 ein und verdrängt mit seiner Stirnfläche 21 Kraftstoff. Diese Verdrängung bewirkt zunächst einmal ein Druckerhöhung in diesem hydraulischen Raum aufgrund der Steifigkeit des hydraulischen Volumens und der elastischen Eigenschaften des darin enthaltenen hydraulischen Mediums. Dies ist im vorliegenden Fall Kraftstoff wie er auch in dem Referenzdruckraum 39 vorhanden ist. Aufgrund des Kolbens 33 ist in Ausgangslage der hydraulische Raum auf einen Druck vorgespannt, der sich aus dem Verhältnis der druckausgesetzten ersten und zweiten Kolbenfläche 36 und 38 ergibt. Aufgrund der Verschiebbarkeit des Kolbens kann dabei der Druck im hydraulischen Druckraum konstant gehalten werden und zwar auf einem gegenüber dem Druck im Referenzdruckraum bzw. im Kraftstoffhochdruckspeicher 1 reduzierten Druck. Dieser Druck in Verbindung mit der Ausgleichsdruckfläche stellt eine zusätzliche Belastung des Ventilgliedes 14 in Schließrichtung dar, die im wesentlichen konstant bleibt und somit als konstanter Faktor ganz wesentlich die Öffnungscharakteristik des Ventilglieds bestimmt. Mit dem Beginn ds Öffnungshubs des Ventilglieds 14 wird das Volumen im hydraulischen Raum 20 vorgespannt, dann aber aufgrund der Verschiebbarkeit des Kolbens 32 konstant gehalten. Der Anstieg der Vorspannung über den Hub wird neben der Kolbenfläche 21 im wesentlichen vom Volumen des hydraulischen Raumes 20 bestimmt. Je nach Druckniveau im Kraftstoffhochdruckspeicher kann eine korrigierende Kraft entgegen dem Öffnungshub des Kraftstoffeinspritz-ventilgliedes 14 eingestellt werden. Dabei spielt auch die Drossel 40 eine Rolle, mit der die Steifigkeit der hydraulischen Säule des hydraulischen Raumes 20 und die rückwirkende Kraft auf das Ventilglied 14 zusätzlich eingestellt werden kann. Insbesondere ist mit dieser Drossel ein dynamisches Verhalten korrigierbar, um einen nicht linearen Kraftanstieg der in Öffnungsrichtung auf das Ventilglied wirkenden Kräfte zu beeinflussen.If, as already described above, an opening process of the Valve member 14 initiated, so the valve member 31st opened and the control pressure chamber 23 to relief pressure relieved, the valve member will begin to open in the direction of opening to move. However, the Diameter larger actuating part 15 further in the hydraulic Space 20 and displaces with its end face 21st Fuel. This displacement initially has an effect Pressure increase in this hydraulic space due to the Rigidity of the hydraulic volume and the elastic Properties of the hydraulic medium contained therein. In the present case, this is fuel as it is in the Reference pressure space 39 is present. Due to the piston 33 in the starting position, the hydraulic space is at one pressure biased, resulting from the ratio of the pressurized results in first and second piston surfaces 36 and 38. Due to the displaceability of the piston, the Pressure in the hydraulic pressure chamber can be kept constant namely on one compared to the pressure in the reference pressure space or reduced pressure in the high-pressure fuel reservoir 1. This pressure in connection with the compensation pressure area places an additional load on the valve member 14 in Closing direction that remains essentially constant and thus, as a constant factor, the Opening characteristic of the valve member determined. With the The beginning of the opening stroke of the valve member 14 is the volume biased in the hydraulic space 20, but then due to the Displaceability of the piston 32 kept constant. The The preload increases over the stroke alongside the piston area 21 essentially from the volume of the hydraulic Room 20 determined. Depending on the pressure level in the high-pressure fuel reservoir can be a corrective force against the Opening stroke of the fuel injection valve member 14 is set become. The throttle 40 also plays one Role with which the rigidity of the hydraulic column of the hydraulic space 20 and the retroactive force on the Valve member 14 can also be adjusted. In particular is a dynamic behavior with this throttle correctable to a non-linear force increase in Forces acting on the valve member in the opening direction influence.

Mit einem solchen Kraftstoffeinspritzventil lassen sich genauer kleinste Kraftstoffeinspritzmengen einspritzen.With such a fuel injection valve Inject the smallest fuel injection quantities more precisely.

Claims (8)

  1. Fuel injection valve having a valve element (14) which is open towards the inside, in opposite direction to the fuel outlet direction, and has a sealing surface (12) which controls an injection opening (9) and to which, upstream of it, a pressure area (7) is connected, which is continuously connected to a fuel high-pressure source (1) and is bounded by a pressure shoulder (18) on the valve element (14), to which pressure shoulder (18) the pressure in the pressure area (7) is applied in the opposite direction to the closing force in the opening direction, and having an operating part (15, 15a) with a pressure surface (26) which is used for operating the valve element (14) in the closing direction, opposing opening forces, which pressure surface (26) is acted on by a control pressure, which can be varied between an operating pressure and relief pressure, in a control pressure area (23) in which case a relief pressure which is set there overcomes the opening forces on the valve element (14), characterized in that a compensating pressure surface (21) is provided, which acts on the valve element (14) and, on one side, bounds a hydraulic area (20), which is bounded on the other side by a first piston surface (36) of a piston (33) with the piston (33) having a second piston surface (38), which faces away from the first piston surface (36) and to which a reference pressure is applied, preferably a constant pressure, in the closing direction of the valve element (14).
  2. Fuel injection valve according to Claim 1, characterized in that the second piston surface area (38) is smaller than the first piston surface area (36) and is used as the reference pressure for the pressure of the fuel high-pressure source.
  3. Fuel injection valve according to Claim 1, characterized in that the compensating pressure surface (21) is dimensioned such that, when the relief pressure is set, the sum of the forces acting in the closing direction is less than the sum of the forces acting in the opening direction.
  4. Fuel injection valve according to Claim 1, characterized in that the forces acting in the closing direction comprise the sum of the forces which result from the pressure applied in the hydraulic area (20) plus the forces resulting from the pressure area (26) and the reduced control pressure, and the forces acting in the opening direction comprise the sum of the forces resulting from the pressure applied to the pressure shoulder (18) and to the sealing surface (12).
  5. Fuel injection valve according to one of the preceding claims, characterized in that the operating part (15, 15a) has an end surface (26) which bounds a control pressure area (23) that holds the control pressure, and the control pressure area is relieved of pressure by means of an electrically controlled control valve (32), or can be kept at the same pressure as the fuel high-pressure source.
  6. Fuel injection valve according to Claim 5, characterized in that the control pressure area (23) is continuously connected via a first restrictor (28) to the fuel high-pressure source (1), and the control valve is a 2/2 valve, by means of which the control pressure area (23) can be relieved of pressure to the relief pressure, in order to initiate high-pressure injection through the fuel injection valve (8).
  7. Fuel injection valve according to Claim 6, characterized in that the pressure in the control pressure area (23) is relieved via a second restrictor (29).
  8. Fuel injection valve according to one of the preceding claims, characterized in that the movement of the piston (33) towards the hydraulic area (20) is limited by a stop (51).
EP98924009A 1997-07-01 1998-03-14 Fuel injection valve Expired - Lifetime EP0923671B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19727896A DE19727896A1 (en) 1997-07-01 1997-07-01 Fuel injector
DE19727896 1997-07-01
PCT/DE1998/000764 WO1999001660A1 (en) 1997-07-01 1998-03-14 Fuel injection valve

Publications (2)

Publication Number Publication Date
EP0923671A1 EP0923671A1 (en) 1999-06-23
EP0923671B1 true EP0923671B1 (en) 2002-06-19

Family

ID=7834193

Family Applications (1)

Application Number Title Priority Date Filing Date
EP98924009A Expired - Lifetime EP0923671B1 (en) 1997-07-01 1998-03-14 Fuel injection valve

Country Status (7)

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US (1) US6367709B2 (en)
EP (1) EP0923671B1 (en)
JP (1) JP2001500215A (en)
KR (1) KR20000068338A (en)
CN (1) CN1089855C (en)
DE (2) DE19727896A1 (en)
WO (1) WO1999001660A1 (en)

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US20010050316A1 (en) 2001-12-13
DE59804494D1 (en) 2002-07-25
US6367709B2 (en) 2002-04-09
JP2001500215A (en) 2001-01-09
CN1231019A (en) 1999-10-06
DE19727896A1 (en) 1999-01-07
CN1089855C (en) 2002-08-28
KR20000068338A (en) 2000-11-25
EP0923671A1 (en) 1999-06-23
WO1999001660A1 (en) 1999-01-14

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