EP0687811B1 - Electromagnetically actuable fuel injection valve - Google Patents

Electromagnetically actuable fuel injection valve Download PDF

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Publication number
EP0687811B1
EP0687811B1 EP95107720A EP95107720A EP0687811B1 EP 0687811 B1 EP0687811 B1 EP 0687811B1 EP 95107720 A EP95107720 A EP 95107720A EP 95107720 A EP95107720 A EP 95107720A EP 0687811 B1 EP0687811 B1 EP 0687811B1
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EP
European Patent Office
Prior art keywords
protective sleeve
fuel injection
valve housing
space
injection valve
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.)
Expired - Lifetime
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EP95107720A
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German (de)
French (fr)
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EP0687811A1 (en
Inventor
Klaus-Henning Krohn
Waldemar Hans
Christian Preussner
Johann Bayer
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Robert Bosch GmbH
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Robert Bosch GmbH
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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
    • F02M51/00Fuel-injection apparatus characterised by being operated electrically
    • F02M51/06Injectors peculiar thereto with means directly operating the valve needle
    • F02M51/061Injectors peculiar thereto with means directly operating the valve needle using electromagnetic operating means
    • F02M51/0625Injectors peculiar thereto with means directly operating the valve needle using electromagnetic operating means characterised by arrangement of mobile armatures
    • F02M51/0664Injectors peculiar thereto with means directly operating the valve needle using electromagnetic operating means characterised by arrangement of mobile armatures having a cylindrically or partly cylindrically shaped armature, e.g. entering the winding; having a plate-shaped or undulated armature entering the winding
    • F02M51/0671Injectors peculiar thereto with means directly operating the valve needle using electromagnetic operating means characterised by arrangement of mobile armatures having a cylindrically or partly cylindrically shaped armature, e.g. entering the winding; having a plate-shaped or undulated armature entering the winding the armature having an elongated valve body attached thereto
    • F02M51/0675Injectors peculiar thereto with means directly operating the valve needle using electromagnetic operating means characterised by arrangement of mobile armatures having a cylindrically or partly cylindrically shaped armature, e.g. entering the winding; having a plate-shaped or undulated armature entering the winding the armature having an elongated valve body attached thereto the valve body having cylindrical guiding or metering portions, e.g. with fuel passages
    • F02M51/0678Injectors peculiar thereto with means directly operating the valve needle using electromagnetic operating means characterised by arrangement of mobile armatures having a cylindrically or partly cylindrically shaped armature, e.g. entering the winding; having a plate-shaped or undulated armature entering the winding the armature having an elongated valve body attached thereto the valve body having cylindrical guiding or metering portions, e.g. with fuel passages all portions having fuel passages, e.g. flats, grooves, diameter reductions
    • 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
    • F02M51/00Fuel-injection apparatus characterised by being operated electrically
    • F02M51/06Injectors peculiar thereto with means directly operating the valve needle
    • F02M51/061Injectors peculiar thereto with means directly operating the valve needle using electromagnetic operating means
    • 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

Definitions

  • the invention is based on an electromagnetically actuated Fuel injection valve according to the type of the main claim (compare DE-C-4230376, FIG. 1)
  • Numerous fuel injection valves are already known also from EP-PS 0 348 786, which has an electrical connector have, via which the electrical contacting a Solenoid coil and thus their excitation takes place.
  • the contacting itself is done via metallic contact pins that come from the solenoid to the actual connector and are largely encapsulated by plastic.
  • the encapsulation encloses here at least partially the valve housing.
  • connection between the plastic encapsulation and the contact pins or the valve housing is not pressure-tight. Much more are about the shrinkage behavior of the plastic after the extrusion coating finest capillary gaps formed that connect of the coil space with the external environment.
  • the coil space of the magnetic coil is heated. It takes place a volume equalization of the heated, expanding air in the Inside the valve with the atmosphere surrounding the valve. If the valve is cooled from a warm operating condition, then Ambient air in the coil space through the capillary gap between the plastic encapsulation and the contact pins or the valve housing sucked in; the inside of the valve "breathes". The cooling takes place of the injection valve by spray water or is at the cooling water on the capillaries, so the Liquid inside the valve, especially in the coil space sucked. The result is corrosion on the contact pins and the coil wire leading to destruction of the coil wire can lead.
  • the training of many is particularly advantageous small channels in the protective sleeve through narrow ribs be formed so that a large internal volume with a large surface area. This ensures that even when vibrating or changing position Liquid is kept away from the capillary gaps.
  • the due to the small channels of capillary holding forces prevent the sucked in from moving Liquid. Via the fuel injector, which is warmed up again and again vaporize the small amounts of liquid sucked in after a short time again, but not The prerequisite for the functioning of the protective sleeve is.
  • FIG. 1 shows a fuel injector
  • Figure 2 shows a section along the line II-II through the fuel injection valve in FIG. 1
  • FIG. 3 another example of channel formation in the protective sleeve.
  • the electromagnetic shown in Figure 1 for example actuable fuel injection valve for fuel injection systems of internal combustion engines has a tubular valve housing 1 made of a ferromagnetic material in which on a coil carrier 2 a magnetic coil 3 is arranged.
  • the coil former 2 partially surrounds a step-shaped, concentric to a valve longitudinal axis 7 extending core 4, which is tubular is formed and via which the fuel is supplied.
  • On its end facing away from the magnet coil 3 encloses the valve housing 1 in the axial direction partially a nozzle body 6.
  • Zur liquid-tight seal between the valve housing 1 and the nozzle body 6 is an annular groove on the circumference of the nozzle body 6 10 formed in which a sealing ring 11 is arranged.
  • Valve needle 21 is used between one of the solenoid 3 facing end face 13 of the Nozzle body 6 and one of the end faces 13 in the axial direction opposite inner shoulder 15 of the valve housing 1 .
  • Two trained for example as a square Guide portions 22 of the valve needle 21 are through guided the guide area of the longitudinal bore 17; but they leave also an axial passage for the fuel free.
  • the valve needle 21 penetrates a through opening with radial play 23 of the stop plate 16 and protrudes at its downstream end with a needle pin 25 from an injection opening 26 of the nozzle body 6 out.
  • the stop plate 16 end facing away from the nozzle body 6 is a truncated cone Seat 28 formed, which serves as a valve closing part End of the valve needle 21 cooperates and the opening or Closes the fuel injector.
  • valve needle 21 is tubular Anchor 30 firmly connected by the anchor 30 with one of the Area 32 facing area 32 a holding part 33 of the valve needle 21 embraces.
  • a return spring 37 On a paragraph facing the solenoid 3 34 of the armature 30 is a return spring 37 with one End at. The return spring is supported at its other end 37 on a tubular adjusting sleeve 40, which in a stepped through hole 41 of the core 4 is pressed.
  • To the connector made of plastic 45 include, for example, two metallic contact pins 46 that directly in connection with the winding of the magnetic coil 3 stand.
  • the contact pins 46 protrude upstream from the Magnetic coil 3 surrounding coil holder 2 and are largely encapsulated by plastic. Only lie at their pin end 47 the contact pins 46 free; so they are not immediately from Plastic enclosed so that a connector with a Corresponding plug part, not shown, is possible.
  • a water spray barrier serving protective sleeve 50 released the fuel injector on the outer circumference at least partially axially and completely radially surrounds.
  • the tubular, for example from a protective sleeve 50 made of plastic is integral, e.g. B. by means of ultrasonic welding, on the plastic jacket 43 tight with the connector 45 facing the upper end attached while the protective sleeve 50 with the valve housing 1 its lower end facing the injection opening 26 with a Game fit surrounds.
  • the breathing air from the injection valve then flows each over the capillary between the metal Valve housing 1 and the plastic casing 43 in between the valve housing 1 and the protective sleeve 50 formed Annular gap.
  • the protective sleeve 50 is stepped executed, similar to the outer contour of the valve housing 1.
  • the protective sleeve 50 surrounds with an outer lower shoulder 53 the valve housing 1, however, at a distance.
  • the between the Protective sleeve 50 and the valve housing 1 formed space 54 is used by "breathing" between the protective sleeve 50 and the valve housing Take up and hold 1 liquid that has been sucked in.
  • the room 54 is divided into numerous small channels or capillaries, through by the inner wall of the protective sleeve 50 ribs 57 projecting radially inwards. Two ribs each 57 delimit an intermediate channel.
  • the Figure 2 shows a section through the fuel injector with the protective sleeve 50 vividly the formation of the ribs 57.
  • the volume of the channels formed between the ribs 57 is much larger than that over the operating temperature range of the Internal combustion engine or the fuel injector occurring breathing volume. This ensures that sucked in Liquid does not get inside the fuel injector reached.
  • the labyrinth of many formed with the ribs 57 small channels prevents even when vibrating or changing position through the capillary holding forces that sucked liquid to the point sealed by the fuel-carrying parts Coil space 49 penetrates.
  • Figure 3 shows a further embodiment for the training of the labyrinth encompassing many channels in the protective sleeve 50.
  • the ribs 57 are now not radial arranged, but in a circular shape. Further, not shown Embodiments with different arrangement of the channels meet as well as the function described.

Description

Stand der TechnikState of the art

Die Erfindung geht aus von einem elektromagnetisch betätigbaren Brennstoffeinspritzventil nach der Gattung des Hauptanspruchs (vergleiche DE-C-4230376, FIG.1) Bekannt sind bereits zahlreiche Brennstoffeinspritzventile, so auch aus der EP-PS 0 348 786, die einen elektrischen Anschlußstecker aufweisen, über den die elektrische Kontaktierung einer Magnetspule und damit deren Erregung erfolgt. Die Kontaktierung an sich erfolgt über metallische Kontaktstifte, die von der Magnetspule bis hin zum eigentlichen Anschlußstecker verlaufen und weitgehend von Kunststoff umspritzt sind. Die Umspritzung umschließt hierbei zumindest teilweise das Ventilgehäuse.The invention is based on an electromagnetically actuated Fuel injection valve according to the type of the main claim (compare DE-C-4230376, FIG. 1) Numerous fuel injection valves are already known also from EP-PS 0 348 786, which has an electrical connector have, via which the electrical contacting a Solenoid coil and thus their excitation takes place. The contacting itself is done via metallic contact pins that come from the solenoid to the actual connector and are largely encapsulated by plastic. The encapsulation encloses here at least partially the valve housing.

Die Verbindung zwischen Kunststoffumspritzung und den Kontaktstiften bzw. dem Ventilgehäuse ist nicht druckdicht. Vielmehr werden über das Schrumpfverhalten des Kunststoffs nach der Umspritzung feinste Kapillarspalte gebildet, die eine Verbindung des Spulenraums mit der äußeren Umgebung darstellen.The connection between the plastic encapsulation and the contact pins or the valve housing is not pressure-tight. Much more are about the shrinkage behavior of the plastic after the extrusion coating finest capillary gaps formed that connect of the coil space with the external environment.

Bei Betrieb der Brennkraftmaschine bzw. des Brennstoffeinspritzventils wird der Spulenraum der Magnetspule erwärmt. Es erfolgt ein Volumenausgleich der erwärmten, sich ausdehnenden Luft im Inneren des Ventils mit der das Ventil umgebenden Atmosphäre. Wird das Ventil aus betriebswarmen Zustand abgekühlt, so wird Umgebungsluft in den Spulenraum über die Kapillarspalte zwischen der Kunststoffumspritzung und den Kontaktstiften bzw. dem Ventilgehäuse angesaugt; das Ventilinnere "atmet". Erfolgt die Abkühlung des Einspritzventils durch Spritzwasser bzw. steht bei der Abkühlung Spritzwasser an den Kapillaren an, so wird die Flüssigkeit in das Innere des Ventils, besonders in den Spulenraum gesaugt. Die Folge ist eine Korrosion an den Kontaktstiften und dem Spulendraht, die bis zu einer Zerstörung des Spulendrahtes führen kann.When operating the internal combustion engine or the fuel injector the coil space of the magnetic coil is heated. It takes place a volume equalization of the heated, expanding air in the Inside the valve with the atmosphere surrounding the valve. If the valve is cooled from a warm operating condition, then Ambient air in the coil space through the capillary gap between the plastic encapsulation and the contact pins or the valve housing sucked in; the inside of the valve "breathes". The cooling takes place of the injection valve by spray water or is at the cooling water on the capillaries, so the Liquid inside the valve, especially in the coil space sucked. The result is corrosion on the contact pins and the coil wire leading to destruction of the coil wire can lead.

Vorteile der ErfindungAdvantages of the invention

Das erfindungsgemäße Brennstoffeinspritzventil mit den kennzeichnenden Merkmalen des Hauptanspruchs hat demgegenüber den Vorteil, daß eine ungehinderte "Atmung" des Ventilinnenraums erfolgen kann, ohne daß anstehendes Spritzwasser oder andere Flüssigkeiten in das Ventilinnere, besonders in den Spulenraum und an die Kontaktstifte, transportiert wird. Vorteilhaft ist es zu diesem Zwecke, eine kostengünstige und robuste Schutzhülse am äußeren Umfang des Ventils zu befestigen, ohne eventuell auftretende Kapillaren zwischen der Kunststoffumspritzung und dem Ventilgehäuse zu verschließen. Anstehende Flüssigkeit wird nämlich nun ohne nennenswerte Widerstände beim "Atmen" des Ventils zwischen das Ventilgehäuse und die Schutzhülse gesaugt, wobei die Flüssigkeit das Ventilinnere nicht erreicht. Dies wird sichergestellt, weil das zwischen Schutzhülse und Ventilgehäuse gebildete Volumen größer ist als das durch die Temperaturerhöhung der im Inneren des Ventils eingeschlossenen Luft gebildete "atmende" Ausgleichsvolumen. The fuel injector according to the invention with the characteristic In contrast, features of the main claim the advantage that unimpeded "breathing" of the valve interior can be done without splashing water or other liquids in the valve interior, especially in the Coil space and to the contact pins, is transported. It is advantageous for this purpose to be an inexpensive and attach robust protective sleeve to the outer circumference of the valve, without any capillaries occurring between the Plastic encapsulation and to close the valve housing. Liquid present is now without any noteworthy Resistance when "breathing" the valve between the valve body and sucked the protective sleeve, the liquid Valve interior not reached. This is ensured because the volume formed between the protective sleeve and the valve housing is greater than that due to the temperature increase inside trapped air formed by the valve Compensation volume.

Durch die in den Unteransprüchen aufgeführten Maßnahmen sind vorteilhafte Weiterbildungen und Verbesserungen des im Hauptanspruch angegebenen Brennstoffeinspritzventils möglich.By the measures listed in the subclaims advantageous further developments and improvements of the Main claim specified fuel injector possible.

Von besonderem Vorteil ist die Ausbildung von zahlreichen kleinen Kanälen in der Schutzhülse, die durch schmale Rippen gebildet werden, so daß ein großes inneres Volumen mit einer großen Oberfläche entsteht. Somit wird gewährleistet, daß auch bei Schwingbelastung oder Lageänderung die eingesaugte Flüssigkeit von den Kapillarspalten ferngehalten wird. Die aufgrund der kleinen Kanäle auftretenden kapillaren Haltekräfte verhindern nämlich ein Verlagern der eingesaugten Flüssigkeit. Über das immer wieder neu erwärmte Brennstoffeinspritzventil dampfen die geringen eingesaugten Flüssigkeitsmengen nach kurzer Zeit wieder ab, was jedoch keine Voraussetzung für das Funktionieren der Schutzhülse ist.The training of many is particularly advantageous small channels in the protective sleeve through narrow ribs be formed so that a large internal volume with a large surface area. This ensures that even when vibrating or changing position Liquid is kept away from the capillary gaps. The due to the small channels of capillary holding forces prevent the sucked in from moving Liquid. Via the fuel injector, which is warmed up again and again vaporize the small amounts of liquid sucked in after a short time again, but not The prerequisite for the functioning of the protective sleeve is.

Von Vorteil kann es sein, eine Ausgleichsbohrung im Ventilgehäuse vorzusehen, wenn die Kapillarspalte nicht für einen drucklosen Volumenausgleich zwischen dem Spulenraum und dem zwischen Ventilgehäuse und Schutzhülse gebildeten Raum ausreichen.It may be advantageous to have a compensating hole in the valve housing to be provided if the capillary gap is not for one unpressurized volume compensation between the coil space and the sufficient space formed between the valve housing and protective sleeve.

Zeichnungdrawing

Ausführungsbeispiele der Erfindung sind in der Zeichnung vereinfacht dargestellt und in der nachfolgenden Beschreibung näher erläutert. Es zeigen Figur 1 ein Brennstoffeinspritzventil, Figur 2 einen Schnitt entlang der Linie II-II durch das Brennstoffeinspritzventil in Figur 1 und Figur 3 ein weiteres Beispiel der Kanalbildung in der Schutzhülse.Embodiments of the invention are in the drawing shown in simplified form and in the description below explained in more detail. 1 shows a fuel injector, Figure 2 shows a section along the line II-II through the fuel injection valve in FIG. 1 and FIG. 3 another example of channel formation in the protective sleeve.

Beschreibung der AusführungsbeispieleDescription of the embodiments

Das in der Figur 1 beispielsweise dargestellte elektromagnetisch betätigbare Brennstoffeinspritzventil für Brennstoffeinspritzanlagen von Brennkraftmaschinen hat ein rohrförmiges Ventilgehäuse 1 aus einem ferromagnetischen Material, in dem auf einem Spulenträger 2 eine Magnetspule 3 angeordnet ist. Der Spulenträger 2 umgibt teilweise einen stufenförmig ausgestalteten, konzentrisch zu einer Ventillängsachse 7 verlaufenden Kern 4, der rohrförmig ausgebildet ist und über den die Brennstoffzufuhr erfolgt. An seinem der Magnetspule 3 abgewandten Ende umschließt das Ventilgehäuse 1 in axialer Richtung teilweise einen Düsenkörper 6. Zur flüssigkeitsdichten Abdichtung zwischen dem Ventilgehäuse 1 und dem Düsenkörper 6 ist am Umfang des Düsenkörpers 6 eine Ringnut 10 ausgebildet, in der ein Dichtring 11 angeordnet ist.The electromagnetic shown in Figure 1, for example actuable fuel injection valve for fuel injection systems of internal combustion engines has a tubular valve housing 1 made of a ferromagnetic material in which on a coil carrier 2 a magnetic coil 3 is arranged. The coil former 2 partially surrounds a step-shaped, concentric to a valve longitudinal axis 7 extending core 4, which is tubular is formed and via which the fuel is supplied. On its end facing away from the magnet coil 3 encloses the valve housing 1 in the axial direction partially a nozzle body 6. Zur liquid-tight seal between the valve housing 1 and the nozzle body 6 is an annular groove on the circumference of the nozzle body 6 10 formed in which a sealing ring 11 is arranged.

Zwischen einer der Magnetspule 3 zugewandten Stirnfläche 13 des Düsenkörpers 6 und einer der Stirnfläche 13 in axialer Richtung gegenüberliegenden Innenschulter 15 des Ventilgehäuses 1 ist eine Anschlagplatte 16 eingeklemmt, die zur Begrenzung der Bewegung einer in einer abgestuften, einen Führungsbereich aufweisenden Längsbohrung 17 des Düsenkörpers 6 angeordneten und in eine abgestufte Längsöffnung 18 des Ventilgehäuses 1 ragenden Ventilnadel 21 dient. Zwei beispielsweise als Vierkante ausgebildete Führungsabschnitte 22 der Ventilnadel 21 werden durch den Führungsbereich der Längsbohrung 17 geführt; sie lassen aber auch einen axialen Durchgang für den Brennstoff frei. Die Ventilnadel 21 durchdringt mit Radialspiel eine Durchgangsöffnung 23 der Anschlagplatte 16 und ragt an ihrem stromabwärtigen Ende mit einem Nadelzapfen 25 aus einer Einspritzöffnung 26 des Düsenkörpers 6 heraus. Am stromabwärtigen, der Anschlagplatte 16 abgewandten Ende ist am Düsenkörper 6 eine kegelstumpfförmige Sitzfläche 28 gebildet, die mit einem als Ventilschließteil dienenden Ende der Ventilnadel 21 zusammenwirkt und das Öffnen bzw. Schließen des Brennstoffeinspritzventils bewirkt. Between one of the solenoid 3 facing end face 13 of the Nozzle body 6 and one of the end faces 13 in the axial direction opposite inner shoulder 15 of the valve housing 1 is one Stop plate 16 clamped to limit movement one in a graded, with a management area Longitudinal bore 17 of the nozzle body 6 arranged and in a stepped longitudinal opening 18 of the valve housing 1 projecting Valve needle 21 is used. Two trained for example as a square Guide portions 22 of the valve needle 21 are through guided the guide area of the longitudinal bore 17; but they leave also an axial passage for the fuel free. The valve needle 21 penetrates a through opening with radial play 23 of the stop plate 16 and protrudes at its downstream end with a needle pin 25 from an injection opening 26 of the nozzle body 6 out. At the downstream, the stop plate 16 end facing away from the nozzle body 6 is a truncated cone Seat 28 formed, which serves as a valve closing part End of the valve needle 21 cooperates and the opening or Closes the fuel injector.

An ihrem anderen Ende ist die Ventilnadel 21 mit einem rohrförmigen Anker 30 fest verbunden, indem der Anker 30 mit einem der Sitzfläche 28 zugewandten Bereich 32 ein Halteteil 33 der Ventilnadel 21 umgreift. An einem der Magnetspule 3 zugewandten Absatz 34 des Ankers 30 liegt eine Rückstellfeder 37 mit ihrem einen Ende an. Mit ihrem anderen Ende stützt sich die Rückstellfeder 37 an einer rohrförmigen Einstellhülse 40 ab, die in eine abgestufte Durchgangsbohrung 41 des Kerns 4 eingepreßt ist.At its other end, the valve needle 21 is tubular Anchor 30 firmly connected by the anchor 30 with one of the Area 32 facing area 32 a holding part 33 of the valve needle 21 embraces. On a paragraph facing the solenoid 3 34 of the armature 30 is a return spring 37 with one End at. The return spring is supported at its other end 37 on a tubular adjusting sleeve 40, which in a stepped through hole 41 of the core 4 is pressed.

Zumindest teilweise sind in axialer Richtung der Kern 4 und das Ventilgehäuse 1 durch eine Kunststoffummantelung 43 umschlossen. Ein elektrischer Anschlußstecker 45, über den die elektrische Kontaktierung der Magnetspule 3 und damit deren Erregung erfolgt, ist beispielsweise zusammen mit der Kunststoffummantelung 43 ausgeformt. Zu dem aus Kunststoff gefertigten Anschlußstecker 45 gehören beispielsweise zwei metallische Kontaktstifte 46, die unmittelbar mit der Wicklung der Magnetspule 3 in Verbindung stehen. Die Kontaktstifte 46 ragen stromaufwärts aus dem die Magnetspule 3 umgebenden Spulenträger 2 heraus und sind weitgehend von Kunststoff umspritzt. Erst an ihrem Stiftende 47 liegen die Kontaktstifte 46 frei; sie sind also nicht unmittelbar von Kunststoff umschlossen, so daß eine Steckverbindung mit einem nicht gezeigten korrespondierenden Steckerteil möglich ist.The core 4 and that are at least partially in the axial direction Valve housing 1 enclosed by a plastic sheath 43. An electrical connector 45 through which the electrical Contacting the solenoid 3 and thus its excitation takes place, is for example together with the plastic jacket 43 molded. To the connector made of plastic 45 include, for example, two metallic contact pins 46 that directly in connection with the winding of the magnetic coil 3 stand. The contact pins 46 protrude upstream from the Magnetic coil 3 surrounding coil holder 2 and are largely encapsulated by plastic. Only lie at their pin end 47 the contact pins 46 free; so they are not immediately from Plastic enclosed so that a connector with a Corresponding plug part, not shown, is possible.

Verbindungen zwischen Kunststoff- und Metallteilen sind nicht vollständig dicht. So ist es auch an Brennstoffeinspritzventilen nicht möglich, eine vollständige Dichtheit im Bereich der mit Kunststoff umspritzten Kontaktstifte 46 und im Bereich des der Einspritzöffnung 26 zugewandten Endes der Kunststoffummantelung 43 auf dem Ventilgehäuse 1 zu gewährleisten. Vielmehr bilden sich feinste Kapillarspalte zwischen den Metallteilen, wie den Kontaktstiften 46 und der Kunststoffummantelung 43. Besonders bei Wärmeeinwirkung wird dieser Effekt noch verstärkt, da die unterschiedlichen Wärmeausdehnungskoeffizienten von Kunststoff und Metall zu Materialverschiebungen führen. Beim Betrieb der Brennkraftmaschine bzw. des Brennstoffeinspritzventils wird gerade durch die Brennkraftmaschine und auch die Aufheizung der Magnetspule 3 eine Temperaturerhöhung im Bereich von Magnetspule 3 und Anschlußstecker 45 verursacht, die wiederum die Bildung von Kapillarspalten erhöht. Die feinsten Kapillarspalten sorgen dafür, daß direkte Verbindungen zwischen der zwischen Spulenträger 2 und Ventilgehäuse 1 eingeschlossenen Luft und der außerhalb des Brennstoffeinspritzventils existierenden Atmosphäre bestehen, so daß das Brennstoffeinspritzventil "atmen" kann.There are no connections between plastic and metal parts completely tight. It is the same with fuel injectors not possible to have a complete tightness in the area of Plastic molded contact pins 46 and in the area of the Injection opening 26 facing the end of the plastic jacket 43 to ensure on the valve housing 1. Rather educate finest capillary gaps between the metal parts, such as the Contact pins 46 and the plastic sheath 43. Especially this effect is increased when exposed to heat, since the different coefficients of thermal expansion of plastic and metal lead to material shifts. When operating the Internal combustion engine or the fuel injector is just by the internal combustion engine and also the heating of the Magnetic coil 3 a temperature increase in the area of the magnetic coil 3 and connector 45 causes, in turn, the formation increased by capillary gaps. The finest capillary gaps provide making direct connections between the between coil bobbins 2 and valve housing 1 trapped air and the outside existing atmosphere of the fuel injector, so that the fuel injector can "breathe".

Bei Temperaturerhöhung im Betrieb des Brennstoffeinspritzventils wird durch die Volumenausdehnung der Magnetspule 3 und der eingeschlossenen Luft der Innendruck über die Kapillarspalte nach außen abgebaut, so daß ein Druckgleichgewicht aufrechterhalten bleibt. Bei Abkühlung erfolgt der Druckausgleich in umgekehrter Richtung. Die Gefahr des Eintritts von Flüssigkeit in das Innere des Brennstoffeinspritzventils ist besonders dann sehr groß, wenn die Brennkraftmaschine stark spritzwassergefährdet ist. Da nicht nur reines Wasser in den Kapillarspalten eingesaugt werden kann, sondern auch andere Partikel (z.B. Salze) mitgenommen werden, kann die Korrosion im Spulenraum 49 sogar noch beschleunigt werden, so daß eine Zerstörung des Spulendrahtes nicht ausgeschlossen ist.When the temperature increases during operation of the fuel injector is enclosed by the volume expansion of the magnet coil 3 and The internal pressure is released via the capillary gaps degraded on the outside so that a pressure balance is maintained remains. When cooling, the pressure equalization takes place in reverse Direction. The risk of liquid entering inside of the fuel injector is particularly large, if the internal combustion engine is at high risk of splashing water. There not only pure water can be sucked into the capillary gaps other particles (e.g. salts) can be taken along, can even accelerate the corrosion in the coil space 49 be so that destruction of the coil wire is not excluded is.

Erfindungsgemäß wird dieses Problem durch eine als Spritzwassersperre dienende Schutzhülse 50 gelöst, die das Brennstoffeinspritzventil am äußeren Umfang zumindest teilweise axial und vollständig radial umgibt. Die rohrförmige, beispielsweise aus einem Kunststoff gefertigte Schutzhülse 50 ist stoffschlüssig, z. B. mittels Ultraschallschweißen, an der Kunststoffummantelung 43 mit dem dem Anschlußstecker 45 zugewandten oberen Ende dicht befestigt, während die Schutzhülse 50 das Ventilgehäuse 1 mit ihrem der Einspritzöffnung 26 zugewandten unteren Ende mit einer Spielpassung umgibt. Damit strömt die atmende Luft des Einspritzventils jeweils über die Kapillare zwischen dem metallenen Ventilgehäuse 1 und der Kunststoffummantelung 43 in einen zwischen dem Ventilgehäuse 1 und der Schutzhülse 50 gebildeten Ringspalt. Außer Kunststoff können auch andere Werkstoffe, wie Metalle, für die Schutzhülse 50 zum Einsatz kommen. Am der Einspritzöffnung 26 zugewandten Ende 52 ist die Schutzhülse 50 gestuft ausgeführt, ähnlich der äußeren Kontur des Ventilgehäuses 1. Mit einem äußeren unteren Absatz 53 umgibt die Schutzhülse 50 das Ventilgehäuse 1 jedoch mit einem Abstand. Der zwischen der Schutzhülse 50 und dem Ventilgehäuse 1 gebildete Raum 54 dient dazu, durch "Atmen" zwischen der Schutzhülse 50 und dem Ventilgehäuse 1 eingesaugte Flüssigkeit aufzunehmen und zu halten.According to the invention, this problem is solved by a water spray barrier serving protective sleeve 50 released the fuel injector on the outer circumference at least partially axially and completely radially surrounds. The tubular, for example from a protective sleeve 50 made of plastic is integral, e.g. B. by means of ultrasonic welding, on the plastic jacket 43 tight with the connector 45 facing the upper end attached while the protective sleeve 50 with the valve housing 1 its lower end facing the injection opening 26 with a Game fit surrounds. The breathing air from the injection valve then flows each over the capillary between the metal Valve housing 1 and the plastic casing 43 in between the valve housing 1 and the protective sleeve 50 formed Annular gap. In addition to plastic, other materials such as Metals for which protective sleeve 50 are used. At the injection port 26 facing end 52, the protective sleeve 50 is stepped executed, similar to the outer contour of the valve housing 1. The protective sleeve 50 surrounds with an outer lower shoulder 53 the valve housing 1, however, at a distance. The between the Protective sleeve 50 and the valve housing 1 formed space 54 is used by "breathing" between the protective sleeve 50 and the valve housing Take up and hold 1 liquid that has been sucked in.

Der Raum 54 ist in zahlreiche kleine Kanäle bzw. Kapillaren gegliedert, die durch von der inneren Wandung der Schutzhülse 50 radial nach innen ragende Rippen 57 entstehen. Jeweils zwei Rippen 57 begrenzen dabei einen dazwischenliegenden Kanal. Die Figur 2 zeigt als ein Schnitt durch das Brennstoffeinspritzventil mit der Schutzhülse 50 anschaulich die Ausbildung der Rippen 57. Das Volumen der zwischen den Rippen 57 gebildeten Kanäle ist wesentlich größer als das über den Betriebstemperaturbereich der Brennkraftmaschine bzw. des Brennstoffeinspritzventils auftretende atmende Volumen. Damit ist gewährleistet, daß eingesaugte Flüssigkeit nicht in das Innere des Brennstoffeinspritzventils gelangt. Das mit den Rippen 57 ausgebildete Labyrinth vieler kleiner Kanäle verhindert sogar bei Schwingbelastung oder Lageänderung durch die kapillaren Haltekräfte, daß eingesaugte Flüssigkeit bis zum von den brennstofführenden Teilen abgedichteten Spulenraum 49 vordringt. The room 54 is divided into numerous small channels or capillaries, through by the inner wall of the protective sleeve 50 ribs 57 projecting radially inwards. Two ribs each 57 delimit an intermediate channel. The Figure 2 shows a section through the fuel injector with the protective sleeve 50 vividly the formation of the ribs 57. The volume of the channels formed between the ribs 57 is much larger than that over the operating temperature range of the Internal combustion engine or the fuel injector occurring breathing volume. This ensures that sucked in Liquid does not get inside the fuel injector reached. The labyrinth of many formed with the ribs 57 small channels prevents even when vibrating or changing position through the capillary holding forces that sucked liquid to the point sealed by the fuel-carrying parts Coil space 49 penetrates.

Von Vorteil kann es sein, eine Ausgleichsbohrung 59 vom Spulenraum 49 zum Umfang des Ventilgehäuses 1 im Bereich der Überdeckung durch die Schutzhülse 50 vorzusehen, wenn die Kapillarspalte nicht für einen drucklosen Volumenausgleich zwischen dem Spulenraum und dem zwischen Ventilgehäuse 1 und Schutzhülse 50 gebildeten Raum 54 ausreichen.It may be advantageous to have a compensating bore 59 from the coil space 49 to the circumference of the valve housing 1 in the area of Cover provided by the protective sleeve 50 when the Capillary gaps not for unpressurized volume compensation between the coil space and between valve housing 1 and Protective sleeve 50 formed space 54 are sufficient.

Die Figur 3 zeigt ein weiteres Ausführungsbeispiel für die Ausbildung des viele Kanäle umfassenden Labyrinths in der Schutzhülse 50. Hierbei sind nun die Rippen 57 nicht radial verlaufend angeordnet, sondern in Kreisform. Weitere, nicht dargestellte Ausführungsformen mit unterschiedlicher Anordnung der Kanäle erfüllen genauso die beschriebene Funktion.Figure 3 shows a further embodiment for the training of the labyrinth encompassing many channels in the protective sleeve 50. Here, the ribs 57 are now not radial arranged, but in a circular shape. Further, not shown Embodiments with different arrangement of the channels meet as well as the function described.

Claims (7)

  1. Electromagnetically actuated fuel injection valve for fuel injection systems of internal combustion engines having a valve housing (1) in a ferromagnetic material, a magnet coil, a coil carrier at least partially surrounding the magnet coil (3), a core (4), an armature (30) interacting with the core, a plastic covering at least partially surrounding the valve housing and an electrical plug (45), likewise made of plastic, which includes at least two contact pins by means of which the excitation of the magnet coil takes place, a protective sleeve (50) surrounding the valve housing (1) completely, at least in the radial direction, wherein at least one region of the protective sleeve (50) is made in such a way that a space (54) occurs, because of a spatial distance between the protective sleeve (50) and the valve housing (1), and one end of the protective sleeve (50) is connected in a leak-tight manner to the plastic covering (43) and the other end of the protective sleeve (50) has clearance relative to the valve housing (1).
  2. Fuel injection valve according to Claim 1, characterized in that the space (54) between the valve housing (1) and the protective sleeve (50) is subdivided by numerous ribs (57) protruding radially inwards from the inner wall of the protective sleeve (50) and, because of this, the space (54) has many small passages.
  3. Fuel injection valve according to Claim 1, characterized in that the space (54) between the valve housing (1) and the protective sleeve (50) is subdivided by numerous ribs (57) which are arranged in circular shape and interleaved and the space (54) has, in consequence, many small passages.
  4. Fuel injection valve according to Claim 1, characterized in that the protective sleeve (50) is manufactured from a plastic and is fastened in a leak-tight manner to the plastic covering (43) by means of ultrasonic welding.
  5. Fuel injection valve according to Claim 1, characterized in that the space (54) is located at the end (52) facing away from the plastic covering (43).
  6. Fuel injection valve according to Claim 1, characterized in that the volume of the space (54) is greater than the breathing volume of the fuel injection valve during the normal operating temperature range.
  7. Fuel injection valve according to one of the preceding claims, characterized in that a balance hole (59) is provided from the coil space (49) to the periphery of the valve housing (1).
EP95107720A 1994-06-18 1995-05-20 Electromagnetically actuable fuel injection valve Expired - Lifetime EP0687811B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4421429A DE4421429A1 (en) 1994-06-18 1994-06-18 Electromagnetically actuated fuel injector
DE4421429 1994-06-18

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EP0687811A1 EP0687811A1 (en) 1995-12-20
EP0687811B1 true EP0687811B1 (en) 1999-03-17

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EP95107720A Expired - Lifetime EP0687811B1 (en) 1994-06-18 1995-05-20 Electromagnetically actuable fuel injection valve

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US (1) US5634597A (en)
EP (1) EP0687811B1 (en)
JP (1) JPH084622A (en)
DE (2) DE4421429A1 (en)
ES (1) ES2131726T3 (en)

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Also Published As

Publication number Publication date
ES2131726T3 (en) 1999-08-01
JPH084622A (en) 1996-01-09
EP0687811A1 (en) 1995-12-20
DE4421429A1 (en) 1995-12-21
DE59505356D1 (en) 1999-04-22
US5634597A (en) 1997-06-03

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