EP0061529B1 - Fuel injection nozzle for internal-combustion engines - Google Patents

Fuel injection nozzle for internal-combustion engines Download PDF

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Publication number
EP0061529B1
EP0061529B1 EP81109692A EP81109692A EP0061529B1 EP 0061529 B1 EP0061529 B1 EP 0061529B1 EP 81109692 A EP81109692 A EP 81109692A EP 81109692 A EP81109692 A EP 81109692A EP 0061529 B1 EP0061529 B1 EP 0061529B1
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EP
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Prior art keywords
section
gap
restricting
neck
bore
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Expired
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EP81109692A
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German (de)
French (fr)
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EP0061529A1 (en
Inventor
Karl Hofmann
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Robert Bosch GmbH
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Robert Bosch GmbH
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/04—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00 having valves, e.g. having a plurality of valves in series
    • F02M61/06—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00 having valves, e.g. having a plurality of valves in series the valves being furnished at seated ends with pintle or plug shaped extensions

Definitions

  • the invention relates to a fuel injection nozzle according to the preamble of the main claim.
  • injection nozzles of this type DE-OS 2 709 892
  • the metering gap for the pre-jet of the fuel at its mouth into the combustion chamber of the machine is directly exposed to the combustion gases, so that it can gradually become clogged by combustion residues. This changes the size of the throttle gap and the metering of the fuel, which adversely affects the engine behavior.
  • a further throttle gap is provided between the conical valve seat and the throttle gap surrounding the cylindrical throttle pin, which is located immediately upstream of the ejection opening and which, alone or together with the throttle gap, at the ejection opening should maintain such high pressure in the fuel jet behind the valve seat that the valve needle is quickly moved into the open position after it has been lifted off the valve seat.
  • the throttle gap surrounding the cylindrical throttle pin and immediately preceding the ejection opening is exposed to the combustion gases, so that it can become clogged by combustion residues.
  • the arrangement according to the invention with the characterizing features of the main claim has the advantage that the metering gap for the fuel pre-jet in the nozzle bore is largely shielded from the attack of the combustion gases by a second throttle gap arranged downstream, the protective gap.
  • the free flow cross-section of the metering gap therefore maintains the prescribed size and shape over a long operating time, so that longer maintenance intervals than previously customary can be provided for such injection nozzles.
  • valve needle and possibly the nozzle bore can be simplified if the pin sections delimiting the restricting gaps and possibly also the wall sections of the nozzle bore delimiting the gaps have the same diameter.
  • the intermediate central section of the nozzle bore is then to be provided with a larger cross section than the sections mentioned.
  • the pin section delimiting the protective gap has a smaller diameter than the pin section delimiting the metering gap and the area of the nozzle bore lying between the columns has the same diameter as the hole area assigned to the metering gap. In this case, there is no central region of the nozzle bore which has an enlarged cross section.
  • the design of the valve needle according to the invention also allows the shape of the pre-jet and, if appropriate, the main jet of the injected fuel to be influenced in the desired manner by appropriate design of the throttle pin.
  • the throttle pin of the pin portion delimiting the protective gap can have a shaping attachment for the spray jet.
  • the section of the nozzle bore lying between the two throttling gaps has a profile in longitudinal section, the geometry of which roughly corresponds to the shape of the throttle pin in the region of the shaping attachment, of the pin portion delimiting the protective gap and its transition corresponds to the pin section with the smaller cross section.
  • FIG. 1 and 2 each show a partial section through one of the exemplary embodiments.
  • valve 1 has a nozzle body 10, in which a valve needle 12 is guided radially and is axially displaceably mounted.
  • a pressure chamber 14 is formed in the nozzle body 10, into which the fuel is introduced and which has a valve seat 16 on the bottom against which a sealing cone 18 of the valve needle 12 is pressed by a closing spring (not shown).
  • the valve seat 16 is followed by a nozzle bore 20, at the mouth of which an ejection opening 22 is formed.
  • a thrust pin 24 engages in the nozzle bore 20 and connects to the sealing cone 18 of the valve needle 12 and is connected to it in one piece.
  • the throttle pin 24 has a first cylindri seen from the sealing cone 18 see pin section 26, which merges conically at a control edge 28 into a pin section 30 with a smaller diameter. This passes over a conical intermediate area into a further cylindrical pin section 32, the diameter of which corresponds approximately to that of the pin section 26.
  • An injection molding neck 34 of the throttle pin is connected to the pin portion 32.
  • the nozzle bore 20 has a first cylindrical wall portion 35, the diameter of which is larger than the diameter of the pin portion 26 by twice the width of a desired annular gap between the pin portion 26 and the nozzle bore.
  • the cylindrical bore section 35 is adjoined by a bore section 36 which initially increases in diameter and then decreases again, which at the ejection opening 22 merges into a cylindrical bore section 38, the diameter of which corresponds to that of the bore section 35.
  • the largest diameter of the central bore section 36 is larger by approximately the difference in diameter between the bore section 35 and the pin section 30 than the pin section 32.
  • the position of the largest diameter of the central bore section 36 is selected such that it is with the valve needle 12 fully raised (right half Fig 1) is located approximately at the height of the pin section 32.
  • the control edge 28 on the pin portion 26 emerges from the bore portion 35 of the nozzle bore, after which the reduced-diameter pin portion 30 releases a larger annular gap between the nozzle bore and the throttle pin, through which the main jet of fuel can pass through virtually unthrottled .
  • its pin section 32 also comes out of the area of the throttle point 42, the cross section of the nozzle bore continuously expanding at this point and the throttling effect being dissolved.
  • the pin portion 32 has entered the area of the largest diameter of the central bore portion 36, so that a through the entire nozzle bore sufficiently large annular gap for unrestricted flow of fuel results.
  • a nozzle bore 44 has a first cylindrical section 46, which merges via a conical section 48 into a second cylindrical section 50 with a smaller diameter.
  • the cylindrical section 46 is formed by a smooth bore in a nozzle body 52, which leads from a pressure chamber 54 in the nozzle body to an end face of the nozzle body.
  • the two other bore sections 48 and 50 of the nozzle bore 44 run in a molding plate 56 which is fastened to the end face of the nozzle body 52, centered by a projection projecting into the bore 46.
  • a throttle pin 58 of a valve needle 60 projects into the nozzle bore 44 and is shaped such that it forms two throttle gaps 62 and 64 in the nozzle bore in the illustrated closed position of the valve needle 60 and delimits them radially inwards.
  • the throttle pin 60 has a first cylindrical section 66 which merges via a conical section 68 into a second cylindrical section 70 of smaller diameter, to which an injection molding pin 72 is attached.
  • the diameter of the cylindrical pin section 66 is smaller than the diameter of the bore section 46 by twice the width of the desired throttle gap 62.
  • the diameter of the pin section 70 is matched to the bore section 50 in the same way.
  • the throttle gap 64 is in front of the throttle gap 62 serving for metering fuel, so that it cannot be impaired by deposits from the combustion gases.
  • the throttle gap 64 contains, so that both the pre-jet and the subsequent main jet of the fuel can spray freely.

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

Description

Die Erfindung geht aus von einer Kraftstoff-Einspritzdüse nach der Gattung des Hauptanspruchs. Bei bekannten Einspritzdüsen dieser Gattung (DE-OS 2 709 892) ist der Zumeßspalt für den Vorstrahl des Kraftstoffs an seiner Ausmündung in die Brennkammer der Maschine unmittelbar den Verbrennungsgasen ausgesetzt, so daß er sich durch Verbrennungsrückstände allmählich zusetzen kann. Dadurch verändert sich die Größe des Drosselspaltes und die Zumessung des Kraftstoffs, wodurch das Motorverhalten nachteilig beeinflußt wird. Bei einer anderen bekannten Einspritzdüse mit einem zylindrischen Drosselzapfen (GB-A-562 033) ist zwischen dem konischen Ventilsitz und den dem zylindrischen Drosselzapfen umgebenden, der Ausspritzöffnung unmittelbar vorgelagerten Drosselspalt ein weiterer Drosselspalt vorgesehen, der allein oder zusammen mit dem Drosselspalt an der Ausspritzöffnung einen so hohen Druck im Kraftstoffstrahl hinter dem Ventilsitz aufrechterhalten soll, daß die Ventilnadel nach dem Abheben vom Ventilsitz rasch in die Offenstellung überführt wird. Jedoch ist auch bei dieser Ausführung der den zylindrischen Drosselzapfen umgebende, der Ausspritzöffnung unmittelbar vorgelagerte Drosselspalt den Verbrennungsgasen ausgesetzt, so daß er sich durch Verbrennungsrückstände zusetzen kann.The invention relates to a fuel injection nozzle according to the preamble of the main claim. In known injection nozzles of this type (DE-OS 2 709 892), the metering gap for the pre-jet of the fuel at its mouth into the combustion chamber of the machine is directly exposed to the combustion gases, so that it can gradually become clogged by combustion residues. This changes the size of the throttle gap and the metering of the fuel, which adversely affects the engine behavior. In another known injection nozzle with a cylindrical throttle pin (GB-A-562 033), a further throttle gap is provided between the conical valve seat and the throttle gap surrounding the cylindrical throttle pin, which is located immediately upstream of the ejection opening and which, alone or together with the throttle gap, at the ejection opening should maintain such high pressure in the fuel jet behind the valve seat that the valve needle is quickly moved into the open position after it has been lifted off the valve seat. However, even in this embodiment, the throttle gap surrounding the cylindrical throttle pin and immediately preceding the ejection opening is exposed to the combustion gases, so that it can become clogged by combustion residues.

Die erfindungsgemäße Anordnung mit den kennzeichnenden Merkmalen des Hauptanspruchs hat demgegenüber den Vorteil, daß der Zumeßspalt für den Kraftstoff-Vorstrahl in der Düsenbohrung durch einen stromab angeordneten zweiten Drosselspalt, den Schutzspalt, vor dem Angriff der Verbrennungsgase weitgehend abgeschirmt ist. Der freie Durchflußquerschnitt des Zumeßspaltes behält daher über eine lange Betriebszeit hinweg die vorgeschriebene Größe und Gestalt bei, so daß für solche Einspritzdüsen längere Wartungsintervalle als bisher üblich vorgesehen werden können.The arrangement according to the invention with the characterizing features of the main claim has the advantage that the metering gap for the fuel pre-jet in the nozzle bore is largely shielded from the attack of the combustion gases by a second throttle gap arranged downstream, the protective gap. The free flow cross-section of the metering gap therefore maintains the prescribed size and shape over a long operating time, so that longer maintenance intervals than previously customary can be provided for such injection nozzles.

Durch die in den Unteransprüchen aufgeführten Maßnahmen sind vorteilhafte Weiterbildungen der im Hauptanspruch angegebenen Anordnung möglich.Advantageous developments of the arrangement specified in the main claim are possible through the measures listed in the subclaims.

Bei Einspritzdüsen, deren Drosselzapfen eine umlaufende Steuerkante an dem der Ausspritzöffnung zugekehrten Ende eines den Zumeßspalt begrenzenden ersten Zapfenabschnitts hat, wird vorgeschlagen, daß sich an die Steuerkante des Drosselzapfens ein Zapfenabschnitt geringeren Querschnitts und daran ein den Schutzspalt begrenzender weiterer Zapfenabschnitt anschließt, und daß die Düsenbohrung in dem zwischen den beiden drosselnden Spalten liegenden Bereich einen gegenüber dem Schutzspalt erweiterten Bohrungsabschnitt hat.In the case of injection nozzles whose throttle pin has a circumferential control edge at the end of a first pin portion delimiting the metering gap, it is proposed that a pin portion of smaller cross-section and then another pin portion delimiting the protective gap adjoin the control edge of the throttle pin, and that the nozzle bore in the area between the two throttling gaps has a widened bore section compared to the protective gap.

Durch entsprechende Gestaltung und Bemessung des erweiterten Bohrungsabschnittes der Düsenbohrung läßt sich erreichen, daß unmittel- _bar nach Beginn des Öffnungshubes der Ventilnadel der Durchflußquerschnitt des vorgelagerten Schutzspaltes sich zu erweitern beginnt und in Hubendstellung der Ventilnadel für den Hauptstrahl des Kraftstoffs ein ungedrosselter Durchgang zur Verfügung steht.By appropriate design and dimensioning of the enlarged bore section of the nozzle bore, it can be achieved that immediately after the opening stroke of the valve needle begins, the flow cross-section of the upstream protective gap begins to widen and an unthrottled passage is available for the main jet of fuel in the end stroke position of the valve needle.

Die Fertigung der Ventilnadel und gegebenenfalls der Düsenbohrung kann vereinfacht werden, wenn die die drosselnden Spalte begrenzenden Zapfenabschnitte und gegebenenfalls auch die die Spalte nach außen begrenzenden Wandabschnitte der Düsenbohrung den gleichen Durchmesser haben. Der dazwischenliegende mittlere Abschnitt der Düsenbohrung ist dann mit einem größeren Querschnitt als die genannten Abschnitte zu versehen.The manufacture of the valve needle and possibly the nozzle bore can be simplified if the pin sections delimiting the restricting gaps and possibly also the wall sections of the nozzle bore delimiting the gaps have the same diameter. The intermediate central section of the nozzle bore is then to be provided with a larger cross section than the sections mentioned.

In einem anderen Fall kann es vorteilhaft sein, wenn der den Schutzspalt begrenzende Zapfenabschnitt einen kleineren Durchmesser als der den Zumeßspalt begrenzende Zapfenabschnitt hat und der zwischen den Spalten liegende Bereich der Düsenbohrung den gleichen Durchmesser wie der dem Zumeßspalt zugeordnete Bohrungsbereich hat. In diesem Fall entfällt ein im Querschnitt erweiterter mittlerer Bereich der Düsenbohrung.In another case, it can be advantageous if the pin section delimiting the protective gap has a smaller diameter than the pin section delimiting the metering gap and the area of the nozzle bore lying between the columns has the same diameter as the hole area assigned to the metering gap. In this case, there is no central region of the nozzle bore which has an enlarged cross section.

Die erfindungsgemäße Ausbildung der Ventilnadel erlaubt es auch, durch entsprechende Gestaltung des Drosselzapfens die Form des Vorstrahls und gegebenenfalls des Hauptstrahls des eingespritzten Kraftstoffes in dem gewünschten Sinne zu beeinflussen. Der Drosselzapfen kann in diesem Fall des den Schutzspalt begrenzendenZapfenabschnittes einen Formgebungsansatzfür den Spritzstrahl haben. Darüber hinaus ist es zu dem beabsichtigten Zweck von Vorteil, wenn der zwischen den beiden drosselnden Spalten liegende Abschnitt der Düsenbohrung im Längsschnitt gesehen ein Profil hat, dessen Geometrie in etwa der Gestalt des Drosselzapfens im Bereich des Formgebungsansatzes, des den Schutzspalt begrenzenden Zapfenabschnitts und dessen Übergang zum Zapfenabschnitt mit dem kleineren Querschnitt entspricht.The design of the valve needle according to the invention also allows the shape of the pre-jet and, if appropriate, the main jet of the injected fuel to be influenced in the desired manner by appropriate design of the throttle pin. In this case, the throttle pin of the pin portion delimiting the protective gap can have a shaping attachment for the spray jet. In addition, it is advantageous for the intended purpose if the section of the nozzle bore lying between the two throttling gaps has a profile in longitudinal section, the geometry of which roughly corresponds to the shape of the throttle pin in the region of the shaping attachment, of the pin portion delimiting the protective gap and its transition corresponds to the pin section with the smaller cross section.

Zwei Ausführungsbeispiele der Erfindung sind in der Zeichnung dargestellt und in der nachfolgenden Beschreibung näher erläutert. die Fig. 1 und 2 zeigen je einen Teilschnitt durch eines der Ausführungsbeispiele.Two embodiments of the invention are shown in the drawing and explained in more detail in the following description. 1 and 2 each show a partial section through one of the exemplary embodiments.

Die Einspritzdüse nach Fig. 1 hat einen Düsenkörper 10, in welchem eine Ventilnadel 12 radial geführt und axial verschiebbar gelagert ist. Im Düsenkörper 10 ist ein Druckraum 14 gebildet, in welchen der Kraftstoff eingeführt ist und welcher am Boden einen Ventilsitz 16 hat, gegen den ein Dichtkegel 18 der Ventilnadel 12 durch eine nicht gezeigte Schließfeder gedrückt ist. An den Ventilsitz 16 schließt sich eine Düsenbohrung 20 an, an deren Mündung eine Ausspritzöffnung 22 gebildet ist.1 has a nozzle body 10, in which a valve needle 12 is guided radially and is axially displaceably mounted. A pressure chamber 14 is formed in the nozzle body 10, into which the fuel is introduced and which has a valve seat 16 on the bottom against which a sealing cone 18 of the valve needle 12 is pressed by a closing spring (not shown). The valve seat 16 is followed by a nozzle bore 20, at the mouth of which an ejection opening 22 is formed.

In die Düsenbohrung 20 greift ein Drasselzapfen 24 ein, der sich an den Dichtkegel 18 der Ventilnadel 12 anschließt und mit dieser einstükkig verbunden ist. Der Drosselzapfen 24 hat vom Dichtkegel 18 aus gesehen einen ersten zylindrisehen Zapfenabschnitt 26, welcher an einer Steuerkante 28 konisch in einen im Durchmesser kleineren Zapfenabschnitt 30 übergeht. Dieser geht über einen konischen Zwischenbereich in einen weiteren zylindrischen Zapfenabschnitt 32 über, dessen Durchmesser in etwa jenem des Zapfenabschnittes 26 entspricht. An den Zapfenabschnitt 32 schließt sich ein Spritzformungsansatz 34 des Drossetzapfens an.A thrust pin 24 engages in the nozzle bore 20 and connects to the sealing cone 18 of the valve needle 12 and is connected to it in one piece. The throttle pin 24 has a first cylindri seen from the sealing cone 18 see pin section 26, which merges conically at a control edge 28 into a pin section 30 with a smaller diameter. This passes over a conical intermediate area into a further cylindrical pin section 32, the diameter of which corresponds approximately to that of the pin section 26. An injection molding neck 34 of the throttle pin is connected to the pin portion 32.

Die Düsenbohrung 20 hat einen ersten zylindrischen Wandabschnitt 35, dessen Durchmesser um die doppelte Breite eines erwünschten Ringspaltes zwischen dem Zapfenabschnitt 26 und der Düsenbohrung größer als der Durchmesser des Zapfenabschnitts 26 ist. An den zylindrischen Bohrungsabschnitt 35 schließt ein im Durchmesser sich zunächst vergrößernder und dann wieder verkleinernder Bohrungsabschnitt 36 an, welcher an der Ausspritzöffnung 22 in einen zylindrischen Bohrungsabschnitt 38 übergeht, dessen Durchmesser jenem des Bohrungsabschnittes 35 entspricht. Der größte Durchmesser des mittleren Bohrungsabschnittes 36 ist etwa um den Durchmesserunterschied zwischen Bohrungsabschnitt 35 und Zapfenabschnitt 30 größer als der Zapfenabschnitt 32. Die Lage des größten Durchmessers des mittleren Bohrungsabschnittes 36 ist etwa so gewählt, daß er sich bei voll angehobener Ventilnadel 12 (rechte Hälfte Fig. 1) in etwa in der Höhe des Zapfenabschnitts 32 befindet.The nozzle bore 20 has a first cylindrical wall portion 35, the diameter of which is larger than the diameter of the pin portion 26 by twice the width of a desired annular gap between the pin portion 26 and the nozzle bore. The cylindrical bore section 35 is adjoined by a bore section 36 which initially increases in diameter and then decreases again, which at the ejection opening 22 merges into a cylindrical bore section 38, the diameter of which corresponds to that of the bore section 35. The largest diameter of the central bore section 36 is larger by approximately the difference in diameter between the bore section 35 and the pin section 30 than the pin section 32. The position of the largest diameter of the central bore section 36 is selected such that it is with the valve needle 12 fully raised (right half Fig 1) is located approximately at the height of the pin section 32.

In der in der linken Hälfte von Fig. 1 dargestellten Schließlage der Einspritzdüse liegt der Dichtkegel 18 der Ventilnadel 12 auf dem Ventilsitz 16 auf. Der Zapfenabschnitt 26 des Drosselzapfens 24 taucht mit dem vorgegebenen Spiel in den Bohrungsabschnitt 35 ein und der Zapfenabschnitt 32 verschließt den Bohrungsabschnitt 38 mit dem gleichen radialen Spiel, oder, wenn funktionell günstiger, mit größerem oder kleinerem Spiel. Dadurch sind in der Schließlage des Ventils zwei radiale Drosselspalte 40 und 42 gebildet, von denen der eine zur Zumessung eines Kraftstoff-Vorstrahls während eines ersten Teilhubs der Ventilnadel dient und der zweite Drosselspalt 42 erfindungsgemäß den ersten vor den Angriffen der Verbrennungsgase schützt. Am Ende des ersten Teilhubes der Ventilnadel 12 tritt die Steuerkante 28 am Zapfenabschnitt 26 aus dem Bohrungsabschnitt 35 der Düsenbohrung aus, wonach der im Durchmesser verkleinerte Zapfenabschnitt 30 einen größeren Ringspalt zwischen Düsenbohrung und Drosselzapfen frei gibt, durch welchen der Hauptstrahl des Kraftstoffs praktisch ungedrosselt hindurchzutreten vermag. Während dieses ersten Teilhubes der Ventilnadel 12 gelangt auch deren Zapfenabschnitt 32 aus dem Bereich der Drosselstelle 42 heraus, wobei sich der Qerschnitt der Düsenbohrung an dieser Stelle ständig erweitert und die Drosselwirkung sich auflöst. Am Ende des vollen Öffnungshubes der Ventilnadel 12, bei welcher diese die in der rechten Hälfte der Fig. 1 dargestellte Lage einnimmt, ist der Zapfenabschnitt 32 in den Bereich des größten Durchmessers des mittleren Bohrungsabschnittes 36 getreten, so daß sich durch die ganze Düsenbohrung hindurch ein ausreichend großer Ringspalt zum ungedrosselten Hindurchströmen des Kraftstoffs ergibt.In the closed position of the injection nozzle shown in the left half of FIG. 1, the sealing cone 18 of the valve needle 12 rests on the valve seat 16. The pin section 26 of the throttle pin 24 dips into the bore section 35 with the predetermined play and the pin section 32 closes the bore section 38 with the same radial play, or, if functionally more favorable, with greater or smaller play. As a result, two radial throttle gaps 40 and 42 are formed in the closed position of the valve, one of which is used to meter a fuel pre-jet during a first partial stroke of the valve needle and the second throttle gap 42 protects the first from the attacks of the combustion gases according to the invention. At the end of the first partial stroke of the valve needle 12, the control edge 28 on the pin portion 26 emerges from the bore portion 35 of the nozzle bore, after which the reduced-diameter pin portion 30 releases a larger annular gap between the nozzle bore and the throttle pin, through which the main jet of fuel can pass through virtually unthrottled . During this first partial stroke of the valve needle 12, its pin section 32 also comes out of the area of the throttle point 42, the cross section of the nozzle bore continuously expanding at this point and the throttling effect being dissolved. At the end of the full opening stroke of the valve needle 12, in which it assumes the position shown in the right half of FIG. 1, the pin portion 32 has entered the area of the largest diameter of the central bore portion 36, so that a through the entire nozzle bore sufficiently large annular gap for unrestricted flow of fuel results.

In der Einspritzdüse nach Fig. 2 hat eine Düsenbohrung 44 einen ersten zylindrischen Abschnitt 46, der über einen kegeligen Abschnitt 48 in einen im Durchmesser kleineren zweiten zylindrischen Abschnitt 50 übergeht. Der zylindrische Abschnitt 46 ist durch eine glatte Bohrung in einem Düsenkörper 52 gebildet, die von einem Druckraum 54 im Düsenkörper bis zu einer Stirnseite des Düsenkörpers führt. Die beiden anderen Bohrungsabschnitte 48 und 50 der Düsenbohrung 44 verlaufen in einer Formplatte 56, welche an der Stirnseite des Düsenkörpers 52, durch einen in die Bohrung 46 passend hineinragenden Ansatz zentriert, befestigt ist.In the injection nozzle according to FIG. 2, a nozzle bore 44 has a first cylindrical section 46, which merges via a conical section 48 into a second cylindrical section 50 with a smaller diameter. The cylindrical section 46 is formed by a smooth bore in a nozzle body 52, which leads from a pressure chamber 54 in the nozzle body to an end face of the nozzle body. The two other bore sections 48 and 50 of the nozzle bore 44 run in a molding plate 56 which is fastened to the end face of the nozzle body 52, centered by a projection projecting into the bore 46.

In die Düsenbohrung 44 ragt ein Drosselzapfen 58 einer Ventilnadel 60 hinein, welcher so geformt ist, daß er in der dargestellten Schließlage der Ventilnadel 60 zwei Drosselspalte 62 und 64 in der Düsenbohrung bildet und radial nach innen begrenzt. Der Drosselzapfen 60 hat einen ersten zylindrischen Abschnitt 66, der über einen kegeligen Abschnitt 68 in einen zweiten zylindrischen Abschnitt 70 kleineren Durchmessers übergeht, an welchen ein Spritzformungszapfen 72 angesetzt ist. Der Durchmesser des zylindrischen Zapfenabschnitts 66 ist um die doppelte Breite des gewünschten Drosselspaltes 62 kleiner als der Durchmesser des Bohrungsabschnittes 46 aufgeführt. Der Durchmesser des Zapfenabschnittes 70 ist in gleicher Weise gegenüber dem Bohrungsabschnitt 50 abgestimmt.A throttle pin 58 of a valve needle 60 projects into the nozzle bore 44 and is shaped such that it forms two throttle gaps 62 and 64 in the nozzle bore in the illustrated closed position of the valve needle 60 and delimits them radially inwards. The throttle pin 60 has a first cylindrical section 66 which merges via a conical section 68 into a second cylindrical section 70 of smaller diameter, to which an injection molding pin 72 is attached. The diameter of the cylindrical pin section 66 is smaller than the diameter of the bore section 46 by twice the width of the desired throttle gap 62. The diameter of the pin section 70 is matched to the bore section 50 in the same way.

In der dargestellten Schließlage ist der Drosselspalt 64 dem der Kraftstoff-Zumessung dienenden Drosselspalt 62 schützend vorgelagert, so daß dieser durch Ablagerungen aus den Verbrennungsgasen nicht beeinträchtigt werden kann. Unmittelbar nach Beginn des Öffnungshubes der Ventilnadel 60 enthält der Drosselspalt 64, so daß sowohl der Vorstrahl als auch der nachfolgende Hauptstrahl des Kraftstoffs ungehindert abspritzen kann.In the closed position shown, the throttle gap 64 is in front of the throttle gap 62 serving for metering fuel, so that it cannot be impaired by deposits from the combustion gases. Immediately after the opening stroke of the valve needle 60 begins, the throttle gap 64 contains, so that both the pre-jet and the subsequent main jet of the fuel can spray freely.

Claims (7)

1. Fuel injection nozzle for internal-combustion engines, having a valve needle (12) opening counter to the flow direction of the fuel, formed onto which is a sealing cone (18), interacting with a valve seat (16) on the nozzle body (10), and onto which then is formed a restricting neck (24), which in the closed position of the valve needle (12) immerses with a cylindrical section (26) into a cylindrical section (35) of the nozzle bore (20) downstream of the valve seat (16) and delimits therein, over the extent of a first partial stroke of the valve needle (12), a restricting metering gap (40) for governing the size of a preliminary fuel jet, characterised in that a further cylindrical section (32, 38) is formed on the restricting neck (24) and/or in the nozzle bore (20) downstream of the metering gap (40), which section, in the closed position of the valve needle (12), forms with an opposite wall section (38, 32) of the nozzle bore (20) or of the restricting neck (24) a protective gap (42) of restricting cross section, the length of which is smaller in the closed position of the valve needle (12) than the length of the metering gap (40) formed in this position, and which extends as the opening stroke of the valve needle (12) begins, enlarging faster than the metering gap (40), up to a cross section not even restricting the main fuel jet.
2. Injection nozzle according to Claim 1, the restricting neck (24) of which has a control edge (28) on the end of the first neck section (26), delimiting the metering gap (40), facing the outlet orifice, characterised in that a neck section (30) of small cross section adjoins the control edge (28) and the other neck section (32) delimiting the protective gap (42) adjoins thereto, and in that the nozzle bore (20) has in the region lying between metering gap (40) and the protective gap (42) a bore section (36) extended with respect to the protective gap (42). 3. Injection nozzle according to Claim 2, characterised in that the neck sections (26, 32) delimiting the restricting gap (40) and the protective gap (42) have the same diameter.
4. Injection nozzle according to Claim 2, characterised in that the neck section (70) delimiting the protective gap (64, Fig. 2) has a smaller diameter than the neck section (66) delimiting the restricting gap (62), and in that the region of the nozzle bore (44) lying between the restricting gap (62) and the protective gap (64) has the same diameter at its widest section as the bore region (46) assigned to the restricting gap (62).
5. Injection nozzle according to one of Claims 2 to 4, characterised in that the restricting neck (24) has a shaping piece (34) for the injection jet downstream of the neck section (32) delimiting the protective gap (42).
6. Injection nozzle according to Claim 5, characterised in that the section (36) of the nozzle bore (20) lying between the restricting gap (40) and the protective gap (42) has a profile, viewed in longitudinal section, the geometry of which corresponds approximately to the form of the restricting neck (24) in the region of the shaping piece (34), of the neck section (32) delimiting the protective gap (42) and its transition to the neck section (30) having the smaller cross section.
7. Injection nozzle according to one of the preceding claims, characterised in that the bore section (50) of the nozzle bore (44) delimiting the protective gap (64, Fig. 2) is formed in an end plate (56) secured on the nozzle body (52).
EP81109692A 1981-03-28 1981-11-14 Fuel injection nozzle for internal-combustion engines Expired EP0061529B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19813112467 DE3112467A1 (en) 1981-03-28 1981-03-28 "FUEL INJECTION NOZZLE FOR INTERNAL COMBUSTION ENGINES"
DE3112467 1981-03-28

Publications (2)

Publication Number Publication Date
EP0061529A1 EP0061529A1 (en) 1982-10-06
EP0061529B1 true EP0061529B1 (en) 1985-06-19

Family

ID=6128671

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81109692A Expired EP0061529B1 (en) 1981-03-28 1981-11-14 Fuel injection nozzle for internal-combustion engines

Country Status (3)

Country Link
EP (1) EP0061529B1 (en)
JP (1) JPS57173556A (en)
DE (2) DE3112467A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2185070B (en) * 1983-07-12 1987-12-09 Lucas Ind Plc Fuel injection nozzles
JP2003501837A (en) * 1999-06-03 2003-01-14 コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ Semiconductor device including high-voltage circuit element

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH227665A (en) * 1941-10-08 1943-06-30 Bosch Gmbh Robert Injection nozzle for internal combustion engines.
GB562033A (en) * 1942-11-11 1944-06-15 William Reginald Cobb Improvements relating to fuel injectors for internal combustion engines
GB950252A (en) * 1961-02-18 1964-02-26 Bosch Gmbh Robert Improvements in fuel injection valves for internal combustion engines
JPS559837B2 (en) * 1973-04-26 1980-03-12
DE2710003A1 (en) * 1977-03-08 1978-09-14 Bosch Gmbh Robert IC engine fuel injector nozzle - has fuel opening located in auxiliary plate screwed to nozzle

Also Published As

Publication number Publication date
JPS57173556A (en) 1982-10-25
DE3112467A1 (en) 1982-12-30
EP0061529A1 (en) 1982-10-06
DE3171063D1 (en) 1985-07-25

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