EP0220207A1 - Fuel injection nozzle for internal combustion engines. - Google Patents

Fuel injection nozzle for internal combustion engines.

Info

Publication number
EP0220207A1
EP0220207A1 EP86901817A EP86901817A EP0220207A1 EP 0220207 A1 EP0220207 A1 EP 0220207A1 EP 86901817 A EP86901817 A EP 86901817A EP 86901817 A EP86901817 A EP 86901817A EP 0220207 A1 EP0220207 A1 EP 0220207A1
Authority
EP
European Patent Office
Prior art keywords
piston
cap
valve needle
fuel
injection nozzle
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.)
Granted
Application number
EP86901817A
Other languages
German (de)
French (fr)
Other versions
EP0220207B1 (en
Inventor
Kurt Seifert
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP0220207A1 publication Critical patent/EP0220207A1/en
Application granted granted Critical
Publication of EP0220207B1 publication Critical patent/EP0220207B1/en
Expired legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • 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
    • F02M61/08—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 opening in direction of fuel flow
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
    • F02M61/20—Closing valves mechanically, e.g. arrangements of springs or weights or permanent magnets; Damping of valve lift
    • F02M61/205—Means specially adapted for varying the spring tension or assisting the spring force to close the injection-valve, e.g. with damping of valve lift

Definitions

  • the invention relates to a fuel injection nozzle according to the preamble of the main claim.
  • Injection nozzles of this type have the advantage that the opening stroke of the valve needle is damped.
  • the pressure piece slidably mounted in the base of the cap transmits the fuel pressure directly to the piston and via this to the valve needle during a preliminary stroke. It is thereby achieved that at the beginning of each injection process, a pre-jet is sprayed with a sufficiently large amount of fuel.
  • the pressure piece has the same diameter as the piston connected to the valve needle.
  • This version can be Process the hole in the cap slightly, but the pre-stroke of the valve needle runs practically completely undamped. In some cases, this can have an undesirable effect on the damping effect of the subsequent partial stroke or, in certain areas of the operating map, can lead to an unfavorable ratio of the pre-injection quantity to the main injection quantity.
  • the arrangement according to the invention with the characterizing features of the main claim has the advantage that the preliminary stroke of the valve needle is partially damped at least in the lower speed and load range.
  • the preliminary stroke of the valve needle is partially damped at least in the lower speed and load range.
  • FIG. 1 shows the first embodiment in longitudinal section and FIG. 2 shows a partial longitudinal section through the second embodiment.
  • FIGS. 3, 4 and 5 show functional diagrams of the injection nozzles according to FIGS. 1 and 2.
  • the injection nozzle according to FIG. 1 has a nozzle body 10 which is clamped to a nozzle holder 14 by a union nut 12.
  • a sleeve 16 Arranged between the nozzle body 10 and the nozzle holder 14 is a sleeve 16 which has an inwardly directed collar 18 which divides a chamber 20 from a chamber 22.
  • a valve seat 24 is formed in the nozzle body 10 and a valve needle 26 is displaceably mounted, the sealing cone 27 of which is pressed against the valve seat 24 by a closing spring 28.
  • the closing spring 28 is supported on the nozzle body 10 and engages via a flange part 30 on a support disk 32, which in turn is supported on a shoulder 34 of the valve needle 26.
  • the nozzle holder 14 contains an inlet bore 36 which opens into the chamber 20, which is connected to the chamber 22 via bores 38, 39 in the collar 18. From this, a bore 4o leads in the nozzle body 10 into an annular space 42, which is formed between the central bore wall of the nozzle body 10 and the circumference of a section 44 of the valve needle 26 which is weakened in diameter and immediately bar up to the valve seat 24. Between the flange part 30 and the nozzle body 10 there is a distance h g in the closed position shown, which corresponds to the total stroke of the valve needle 26. The valve needle 26 is displaced outward in the opening direction by the fuel pressure against the force of the closing spring 28 until the flange part 30 strikes the nozzle body 10. When the valve closes, the closing spring 28 returns the valve needle 26 inward to the closed position shown.
  • a piston 46 which passes through the collar 18 and projects into the chamber 20, is integrally formed on the valve needle 26 above the shoulder 34.
  • the diameter of the piston 46 corresponds to the guide diameter of the valve needle 26.
  • a cap 48 with a predetermined radial clearance is fitted on the piston 46, which has a flange 50 and is pressed against the collar 18 by a return spring 52.
  • the return spring 52 is supported on an annular shoulder 54 of the nozzle holder 14, which is formed at the transition from the chamber 20 to an enlarged section 56 of the inlet bore 36.
  • the cap 48 has a bottom 58, in which a pressure piece 60 is slidably mounted, which has a smaller diameter than the piston 46.
  • a fuel-filled damping space 62 is formed in the cap 48 between the end face of the piston 46 and the base 58 and is connected to the chambers 20, 22 and therefore to the flow path of the fuel via the bearing clearances of the piston 46 and the pressure piece 60.
  • the pressure piece 60 projects into the damping space 62 at the bottom and has an annular collar 64 at the top, on which a return spring 66 engages, which is supported on an annular shoulder 68 of the nozzle holder 14. In the starting position shown, the pressure piece 60 bears against the piston 46, its collar 64 being a distance h v from the upper end face of the cap 46.
  • the distance h v corresponds to a preliminary stroke of the valve needle, at which the valve needle is to experience a weaker damping in a certain area of the operating characteristic map than with the remaining stroke.
  • the parts assume the position shown in FIG. 1, in which the damping space 62 has its smallest volume.
  • the increasing fuel pressure now acts in full via the pressure piece 60 and throttled on the annular surface of the piston 46 not covered by the pressure piece 60.
  • the valve needle 26 is thereby displaced in the opening direction until after the advance stroke h v the pressure piece 60 comes to rest on the cap 48.
  • this process is represented by the partial distance a. Because the damping space 62 increases in this process, the movement of the valve needle 26 takes place more slowly than in the known arrangement in which the pressure piece 60 has the same diameter as the piston 46 and the damping space 60 does not enlarge during the preliminary stroke.
  • the closing spring 28 returns the valve needle 26 upwards into the closed position, whereby the cap 48 together with the pressure piece 60 also lifts and then through its return spring 52 in accordance with the throttling in the bearing gaps of the piston 46 and pressure piece 60 in the illustrated Starting position is reduced.
  • the valve needle 26 can advantageously only perform the preliminary stroke h v , as is shown in the diagram in FIG. 4.
  • the injection nozzle according to FIG. 2 differs from that according to FIG. 1 in that a cap 70 fitted onto the piston 46 is supported on the collar 18 fixed to the housing by means of a prestressed support spring 72, the annular shoulder 54 of the nozzle holder 1 4 catching the cap 70 upwards .
  • the pressure piece 60 acts, as in the above-described embodiment, directly on the piston 46 during a preliminary stroke h v and then comes to bear against the cap 70.
  • the pressure difference between the damping space 62 and the chamber 20 increases because the cap 70 initially cannot follow the movement of the valve needle 26 due to the action of the prestressed support spring 72.
  • the support spring 72 is designed so that its bias is not overcome in idle and in the medium speed range, so that the damping is effective over the entire needle stroke. In the upper speed and load range, the pressure difference between the chamber 20 and the damping chamber 62 increases to such an extent that the pretension of the support spring 72 is overcome.

Landscapes

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

Abstract

Un injecteur de carburant pour moteurs à combustion interne possédant un pointeau de soupape (26) s'ouvrant vers l'extérieur relié à un piston (46) qui délimite un espace d'amortissement (62) rempli de carburant, qui, pendant le cycle d'ouverture n'est relié à la trajectoire d'écoulement du carburant que par un passage d'étranglement. L'espace d'amortissement (62) est formé d'un capuchon (48) monté sur le piston (46). A la base (58) du capuchon (48) se trouve un élément de transmission de pression (60) commandé par le carburant qui presse directement sur le piston (46) pendant la course préliminaire (hv), puis vient reposer sur le capuchon (48). L'élément de transmission de pression (60) possède un diamètre plus petit que le piston (46), de sorte que la course préliminaire (hv) du pointeau (26) de la soupape est plus ou moins amortie au moins dans la faible gamme de t/m et de charge.A fuel injector for internal combustion engines having an outwardly opening valve needle (26) connected to a piston (46) which defines a damping space (62) filled with fuel, which during the cycle opening is connected to the fuel flow path only by a throttle passage. The damping space (62) is formed by a cap (48) mounted on the piston (46). At the base (58) of the cap (48) is a pressure transmission element (60) controlled by the fuel which presses directly on the piston (46) during the preliminary stroke (hv), then comes to rest on the cap ( 48). The pressure transmitting element (60) has a smaller diameter than the piston (46), so that the preliminary stroke (hv) of the needle (26) of the valve is more or less damped at least in the low range of t / m and load.

Description

Kraftstoff-Einspritzdüse für Brennkraft-maschinenFuel injection nozzle for internal combustion engines
Stand der TechnikState of the art
Die Erfindung geht aus von einer Kraftstoff-Einspritzdüse nach der Gattung des Hauptanspruchs. Einspritzdüsen dieser Gattung haben den Vorteil, daß der Öffnungshub der Ventilnadel gedämpft erfolgt. Durch entsprechende Abstimmung von Drosselkanal und Rückführfeder der Kappe kann erreicht werden, daß die Dämpfung in bestimmten Bereichen des Betriebkennfeldes nur über einen Teilhub der Ventilnadel wirksam ist. Das im Boden der Kappe verschiebbar gelagerte Druckstück überträgt während eines Vorhubes den Kraftstoffdruck direkt auf den Kolben und über diesen auf die Ventilnadel. Dadurch ist erreicht, daß zu Beginn eines jeden Einspritzvorganges ein Vorstrahl mit einer ausreichend großen Kraftstoffmenge ausgespritzt wird.The invention relates to a fuel injection nozzle according to the preamble of the main claim. Injection nozzles of this type have the advantage that the opening stroke of the valve needle is damped. By appropriate adjustment of the throttle channel and the return spring of the cap, it can be achieved that the damping in certain areas of the operating map is only effective over a partial stroke of the valve needle. The pressure piece slidably mounted in the base of the cap transmits the fuel pressure directly to the piston and via this to the valve needle during a preliminary stroke. It is thereby achieved that at the beginning of each injection process, a pre-jet is sprayed with a sufficiently large amount of fuel.
Bei einer bekannten Einspritzdüse der gattungsmäßigen Art (DE-Al 33 07 67 1 , Figur 2), hat das Druckstück den gleichen Durchmesser wie der mit der Ventilnadel verbundene Kolben. Bei dieser Ausführung läßt sich zwar die Bohrung in der Kappe leicht bearbeiten, jedoch läuft der Vorhub der Ventilnadel praktisch völlig ungedämpft ab. Das kann in manchen Fällen die Dämpfungswirkung des nachfolgenden Teilhubs unerwünscht beeinflussen oder in bestimmten Bereichen des Betriebskennfeldes zu einem ungünstigen Verhältnis der Voreinspritzmenge zur Haupteinspritzmenge führen.In a known injection nozzle of the generic type (DE-Al 33 07 67 1, Figure 2), the pressure piece has the same diameter as the piston connected to the valve needle. This version can be Process the hole in the cap slightly, but the pre-stroke of the valve needle runs practically completely undamped. In some cases, this can have an undesirable effect on the damping effect of the subsequent partial stroke or, in certain areas of the operating map, can lead to an unfavorable ratio of the pre-injection quantity to the main injection quantity.
Vorteile der Erf indungAdvantages of the Invention
Die erfindungsgemäße Anordnung mit den kennzeichnenden Merkmalen des Hauptanspruchs hat demgegenüber den Vorteil, daß der Vorhub der Ventilnadel zumindest im unteren Drehzahl- und Lastbereich teilweise gedämpft erfolgt. Durch gezielte Abstimmung der Durchmesser von Druckstück und Kolben mit dem in den Dämpfungsraum führenden Drosselkanal (Lagerspiele von Druckstück und Kolben) kann erreicht werden, daß bei Leerlauf der Maschine der gesamte Öffnungshub der Ventilnadel auf die Größe des Vorhubes beschränkt bleibt. Durch entsprechende Bemessung der Rückführfeder des Druckstücks und seines Lagerspaltes kann erreicht werden, daß das Druckstück in den Spritzpausen seine Ausgangslage, in der es am Kolben anliegt, nicht erreicht, so daß der Vorhub mindestens teilweise auch ungedämpft verläuft. Ein solcher Einspritzverlauf kann besonders bei hohen Drehzahlen und bei Vollast zur schnellen Einspritzung einer größeren Kraftstoffmenge vorteilhaft sein.The arrangement according to the invention with the characterizing features of the main claim has the advantage that the preliminary stroke of the valve needle is partially damped at least in the lower speed and load range. Through targeted coordination of the diameter of the pressure piece and piston with the throttle channel leading into the damping chamber (bearing play of the pressure piece and piston) it can be achieved that when the machine is idling, the entire opening stroke of the valve needle remains limited to the size of the preliminary stroke. By appropriate dimensioning of the return spring of the pressure piece and its bearing gap, it can be achieved that the pressure piece does not reach its starting position, in which it rests on the piston, during the spraying breaks, so that the preliminary stroke is also at least partially undamped. Such an injection profile can be advantageous, in particular at high speeds and at full load, for the rapid injection of a large amount of fuel.
Die Unteransprüche enthalten Maßnahmen zum vorteilhaften Weiterbilden des Gegenstandes des Hauptanspruchs. Zei chnungThe subclaims contain measures for the advantageous further development of the subject matter of the main claim. Drawing
Zwei Ausführungsbeispiele der Erfindung sind in der Zeichnung dargestellt und in der nachfolgenden Beschreibung näher erläutert. Es zeigen Figur 1 das erste Ausführungsbeispiel im Längsschnitt und Figur 2 einen Teil-Längsschnitt durch das zweite Ausführungsbeispiel. In den Figuren 3, 4 und 5 sind Funktionsschaubilder der Einspritzdüsen nach den Figuren 1 und 2 dargestellt.Two embodiments of the invention are shown in the drawing and explained in more detail in the following description. 1 shows the first embodiment in longitudinal section and FIG. 2 shows a partial longitudinal section through the second embodiment. FIGS. 3, 4 and 5 show functional diagrams of the injection nozzles according to FIGS. 1 and 2.
Beschreibung der AusführungsbeispieleDescription of the embodiments
Die Einspritzdüse nach Figur 1 hat einen Düsenkörper 10, der durch eine Überwurfmutter 12 an ei,pem Düsenhalter 14 festgespannt ist. Zwischen dem Düsenkörper 10 und dem Düsenhalter 14 ist eine Hülse 16 angeordnet, welche einen nach innen gerichteten Kragen 18 hat, der eine Kammer 20 von einer Kammer 22 abteilt. Im Düsenkörper 10 ist ein Ventilsitz 24 gebildet und eine Ventilnadel 26 verschiebbar gelagert, deren Dichtkegel 27 von einer Schließfeder 28 gegen den Ventilsitz 24 gedrückt ist. Die Schließfeder 28 stützt sich am Düsenkörper 10 ab und greift über ein Flanschteil 30 an einer Stützscheibe 32 an, die sich ihrerseits an einer Schulter 34 der Ventilnadel 26 abstützt.The injection nozzle according to FIG. 1 has a nozzle body 10 which is clamped to a nozzle holder 14 by a union nut 12. Arranged between the nozzle body 10 and the nozzle holder 14 is a sleeve 16 which has an inwardly directed collar 18 which divides a chamber 20 from a chamber 22. A valve seat 24 is formed in the nozzle body 10 and a valve needle 26 is displaceably mounted, the sealing cone 27 of which is pressed against the valve seat 24 by a closing spring 28. The closing spring 28 is supported on the nozzle body 10 and engages via a flange part 30 on a support disk 32, which in turn is supported on a shoulder 34 of the valve needle 26.
Der Düsenhalter 14 enthält eine Zulaufbohrung 36, welche in die Kammer 20 einmündet, die über Bohrungen 38, 39 im Kragen 18 mit der Kammer 22 verbunden ist. Aus dieser führt eine Bohrung 4o im Düsenkörper 10 in einen Ringraum 42 , der zwischen der zentralen Bohrungswand des Düsenkörpers 10 und dem Mantelumfang eines im Durchmesser geschwächten Abschnittes 44 der Ventilnadel 26 gebildet ist und unmittel bar bis vor den Ventilsitz 24 reicht. Zwischen dem Flanschteil 30 und dem Düsenkörper 10 ist in der dargestellten Schließlage ein Abstand hg vorhanden, welcher dem Gesamthub der Ventilnadel 26 entspricht. Die Ventilnadel 26 wird vom Kraftstoffdruck gegen die Kraft der Schließfeder 28 nach außen in Öffnungsrichtung verschoben, bis der Flanschteil 30 am Düsenkörper 10 anschlägt. Beim Schließen des Ventils führt die Schließfeder 28 die Ventilnadel 26 nach innen in die dargestellte Schließlage zurück.The nozzle holder 14 contains an inlet bore 36 which opens into the chamber 20, which is connected to the chamber 22 via bores 38, 39 in the collar 18. From this, a bore 4o leads in the nozzle body 10 into an annular space 42, which is formed between the central bore wall of the nozzle body 10 and the circumference of a section 44 of the valve needle 26 which is weakened in diameter and immediately bar up to the valve seat 24. Between the flange part 30 and the nozzle body 10 there is a distance h g in the closed position shown, which corresponds to the total stroke of the valve needle 26. The valve needle 26 is displaced outward in the opening direction by the fuel pressure against the force of the closing spring 28 until the flange part 30 strikes the nozzle body 10. When the valve closes, the closing spring 28 returns the valve needle 26 inward to the closed position shown.
An die Ventilnadel 26 ist oberhalb der Schulter 34 ein Kolben 46 einstückig angeformt, welcher durch den Kragen 18 hindurchtritt und in die Kammer 20 ragt. Der Durchmesser des Kolbens 46 entspricht dem Führungsdurchmesser der Ventilnadel 26. Auf dem Kolben 46 ist eine Kappe 48 mit vorgegebenem Radialspiel aufgesteckt, die einen Flanschrand 50 hat und von einer Rückführfeder 52 gegen den Kragen 18 gedrückt ist. Die Rückführfeder 52 stützt sich dabei an einer Ringschulter 54 des Düsenhalters 14 ab, die am Übergang der Kammer 20 zu einem erweiterten Abschnitt 56 der Zulaufbohrung 36 gebildet ist.A piston 46, which passes through the collar 18 and projects into the chamber 20, is integrally formed on the valve needle 26 above the shoulder 34. The diameter of the piston 46 corresponds to the guide diameter of the valve needle 26. A cap 48 with a predetermined radial clearance is fitted on the piston 46, which has a flange 50 and is pressed against the collar 18 by a return spring 52. The return spring 52 is supported on an annular shoulder 54 of the nozzle holder 14, which is formed at the transition from the chamber 20 to an enlarged section 56 of the inlet bore 36.
Die Kappe 48 hat einen Boden 58, in welchem ein Druckstück 60 verschiebbar gelagert ist, welches einen kleineren Durchmesser als der Kolben 46 hat. Zwischen der Stirnseite des Kolbens 46 und dem Boden 58 ist ein mit Kraftstoff gefüllter Dämpfungsraum 62 in der Kappe 48 gebildet, welcher über die Lagerspiele des Kolbens 46 und des Druckstückes 60 mit den Kammern 20, 22 und daher mit dem Strömungsweg des Kraftstoffs verbunden ist. Das Druckstück 60 ragt unten in den Dämpfungsraum 62 hinein und hat oben einen Ringbund 64 , an welchem eine Rückführfeder 66 angreift, die sich an einer Ringschulter 68 des Düsenhalters 14 abstützt. In der dargestellten Ausgangslage liegt das Druckstück 60 am Kolben 46 an, wobei sein Ringbund 64 von der oberen Stirnseite der Kappe 46 um einen Abstand hv entfernt ist. Der Abstand hv entspricht einem Vorhub der Ventilnadel, bei welchem die Ventilnadel in einem bestimmten Bereich des Betriebskennfeldes eine schwächere Dämpfung erfahren soll als bei dem verbleibenden Resthub.The cap 48 has a bottom 58, in which a pressure piece 60 is slidably mounted, which has a smaller diameter than the piston 46. A fuel-filled damping space 62 is formed in the cap 48 between the end face of the piston 46 and the base 58 and is connected to the chambers 20, 22 and therefore to the flow path of the fuel via the bearing clearances of the piston 46 and the pressure piece 60. The pressure piece 60 projects into the damping space 62 at the bottom and has an annular collar 64 at the top, on which a return spring 66 engages, which is supported on an annular shoulder 68 of the nozzle holder 14. In the starting position shown, the pressure piece 60 bears against the piston 46, its collar 64 being a distance h v from the upper end face of the cap 46. The distance h v corresponds to a preliminary stroke of the valve needle, at which the valve needle is to experience a weaker damping in a certain area of the operating characteristic map than with the remaining stroke.
Die Einspritzdüse nach Figur 1 arbeitet wie folgt:The injection nozzle according to Figure 1 works as follows:
Am Beginn eines Einspritzvorgangs nehmen die Teile die in Figur 1 gezeigte Lage ein, in welcher der Dämpfungsraum 62 sein kleinstes Volumen hat. Der ansteigende Kraftstoffdruck wirkt nun über das Druckstück 60 in voller Höhe und auf der vom Druckstück 60 nicht bedeckten Ringfläche des Kolbens 46 gedrosselt ein. Die Ventilnadel 26 wird dadurch in Öffnungsrichtung verschoben, bis nach Zurücklegung des Vorhubes hv das Druckstück 60 zur Anlage an der Kappe 48 kommt.At the beginning of an injection process, the parts assume the position shown in FIG. 1, in which the damping space 62 has its smallest volume. The increasing fuel pressure now acts in full via the pressure piece 60 and throttled on the annular surface of the piston 46 not covered by the pressure piece 60. The valve needle 26 is thereby displaced in the opening direction until after the advance stroke h v the pressure piece 60 comes to rest on the cap 48.
Im Funktionsschaubild nach Figur 3, welches den Ventilnadelhub h über der Spritzdauer t zeigt , ist dieser Vorgang durch die Teilstrecke a dargestellt. Weil sich bei diesem Vorgang der Dämpfungsraum 62 vergrößert, erfolgt die Bewegung der Ventilnadel 26 langsamer als bei der bekannten Anordnung, bei welcher das Druckstück 60 den gleichen Durchmesser wie der Kolben 46 hat und eine Vergrößerung des Dämpfungsraums 60 während des Vorhubes nicht eintritt.In the functional diagram according to FIG. 3, which shows the valve needle stroke h over the injection duration t, this process is represented by the partial distance a. Because the damping space 62 increases in this process, the movement of the valve needle 26 takes place more slowly than in the known arrangement in which the pressure piece 60 has the same diameter as the piston 46 and the damping space 60 does not enlarge during the preliminary stroke.
Nach dem Aufsetzen des Druckstücks 60 auf die gehäusefest abgestützte Kappe 48 wirkt allein der Kraftstoffdruck im Dämpfungsraum 62 auf die Ventilnadel ein, wodurch sich eine stärkere Dämpfung der weiteren Ventilnadelbewegung als vorher ergibt. In Figur 3 ist dieser Vorgang durch die Teil strecke b gekennzeichnet, die flacher als die Teilstrecke a verläuft. Je nach Betriebspunkt wird ein Endhub he der Ventilnadel erreicht, der bei Vollast und hoher Drehzahl demAfter the pressure piece 60 has been placed on the cap 48, which is fixed to the housing, only the fuel pressure in the damping space 62 acts on the valve needle, which results in greater damping of the further valve needle movement than before. In Figure 3, this process is by part marked route b, which is flatter than section a. Depending on the operating point, a final stroke h e of the valve needle is achieved, which at full load and high speed
Gesamthub hg entspricht. Dieser Betriebspunkt ist. in Figur 3 durch den gestrichelten Linienzug angedeutet.Total stroke h g corresponds. This operating point is. indicated in Figure 3 by the dashed line.
Am Ende des Einspritzvorganges führt die Schließfeder 28 die Ventilnadel 26 nach oben in die Schließlage zurück, wobei sich auch die Kappe 48 samt Druckstück 60 anhebt und danach durch ihre Rückführfeder 52 nach Maßgabe der Drosselung in den Lagerspalten von Kolben 46 und Druckstück 60 in die dargestellte Ausgangslage zurückgeführt wird. Im Leerlaufbetrieb kann die Ventilnadel 26 vorteilhaft nur den Vorhub hv ausführen, wie in dem Schaubild nach Figur 4 gezeigt ist.At the end of the injection process, the closing spring 28 returns the valve needle 26 upwards into the closed position, whereby the cap 48 together with the pressure piece 60 also lifts and then through its return spring 52 in accordance with the throttling in the bearing gaps of the piston 46 and pressure piece 60 in the illustrated Starting position is reduced. In idle mode, the valve needle 26 can advantageously only perform the preliminary stroke h v , as is shown in the diagram in FIG. 4.
Die Einspritzdüse nach Figur 2 weicht von jener nach Figur 1 dadurch, ab, daß eine auf den Kolben 46 aufgesteckte Kappe 70 über eine vorgespannte Stützfeder 72 am gehäusefesten Kragen 18 abgestützt ist, wobei die Ringschulter 54 des Düsenhalters 1 4 die Kappe 70 nach oben abfängt.The injection nozzle according to FIG. 2 differs from that according to FIG. 1 in that a cap 70 fitted onto the piston 46 is supported on the collar 18 fixed to the housing by means of a prestressed support spring 72, the annular shoulder 54 of the nozzle holder 1 4 catching the cap 70 upwards .
Das Druckstück 60 wirkt wie bei der vorbeschriebenen Ausführung während eines Vorhubes hv unmittelbar auf den Kolben 46 und kommt danach zur Anlage an der Kappe 70. Bei weiter ansteigendem Kraftstoffdruck vergrößert sich die Druckdifferenz zwischen dem Dämpfungsraum 62 und der Kammer 20, weil die Kappe 70 wegen der Einwirkung der vorgespannten Stützfeder 72 der Bewegung der Ventilnadel 26 zunächst nicht folgen kann. Die Stützfeder 72 ist so ausgelegt, daß ihre Vorspannung im Leerlauf und im mittleren Drehzahlbereich nicht überwunden wird, so daß dabei die Dämpfung über den gesamten Nadelhub wirksam ist. Im oberen Drehzahl- und Lastbereich steigt die Druckdifferenz zwischen der Kammer 20 und dem Dämpfungsraum 62 soweit an, daß die Vorspannung der Stützfeder 72 überwunden wird. Danach folgt unter Zusammendrücken der Stützfeder 72 die Kappe 70 der Ventilnadel 26, wodurch die Dämpfungswirkung weitgehend aufgehoben wird. Die Ventilnadel 26 wird dabei rasch in die volle Offenstellung überführt, was im Schaubild nach Figur 5 durch die Teilstrecke c dargestellt ist. Durch entsprechende Wahl bzw. Einstellung der Stützfeder 72 kann so die Dämpfungwirkung auf ein gewünschtes Maß druckabhängig begrenzt werden. The pressure piece 60 acts, as in the above-described embodiment, directly on the piston 46 during a preliminary stroke h v and then comes to bear against the cap 70. As the fuel pressure increases further, the pressure difference between the damping space 62 and the chamber 20 increases because the cap 70 initially cannot follow the movement of the valve needle 26 due to the action of the prestressed support spring 72. The support spring 72 is designed so that its bias is not overcome in idle and in the medium speed range, so that the damping is effective over the entire needle stroke. In the upper speed and load range, the pressure difference between the chamber 20 and the damping chamber 62 increases to such an extent that the pretension of the support spring 72 is overcome. This is followed by compression of the support spring 72, the cap 70 of the valve needle 26, whereby the damping effect is largely canceled. The valve needle 26 is quickly moved to the full open position, which is shown in the diagram of Figure 5 by the section c. By appropriate choice or adjustment of the support spring 72, the damping effect can be limited to a desired level depending on the pressure.

Claims

Ansprüche Expectations
1. Kraftstoff-Einspritzdüse für Brennkraftmaschinen, mit einer Ventilnadel, die sich beim Öffnungshub in Strömungsrichtung des Kraftstoffs verschiebt und die mit einem Kolben verbunden ist, der einen mit Kraftstoff gefüllten Dämpfungsraum begrenzt, welcher nur über einen Drosselkanal mit dem Strömungsweg des Kraftstoffs verbunden und in einer auf den Kolben aufgesteckten Kappe gebildet ist, die mindestens in einem bestimmten Bereich des Betriebskennfeldes gegenüber der in Öffnungsrichtung sich bewegenden Ventilnadel zurückgehalten ist, und ferner mit einem im Boden der Kappe verschiebbar gelagerten Druckstück, welches an der vom Dämpfungsraum abgekehrten Stirnseite von einer Rückführfeder und vom Kraftstoffdruck im Strömungsweg beaufschlagt ist, zu Beginn eines Öffnungshubes am Kolben anliegt und nach einem Vorhub der Ventilnadel an einer seine Weiterbewegung verhindernden Schulter der Kappe zur Anlage kommt, dadurch gekennzeichnet, daß das im Boden (58) der Kappe (48, 70) gelagerte Druckstück (60) einen kleineren Durchmesser als der mit der Ventilnadel (26) verbundene Kolben ( 46 ) hat.1.Fuel injector for internal combustion engines, with a valve needle that moves in the opening direction in the flow direction of the fuel and which is connected to a piston which delimits a fuel-filled damping space, which is connected to the flow path of the fuel only via a throttle channel and in a cap fitted to the piston is formed, which is held back at least in a certain area of the operating map with respect to the valve needle moving in the opening direction, and furthermore with a pressure piece which is displaceably mounted in the bottom of the cap and which is supported by a return spring on the front side facing away from the damping chamber and is acted upon by the fuel pressure in the flow path, abuts the piston at the beginning of an opening stroke and, after a preliminary stroke of the valve needle, comes into contact with a shoulder of the cap preventing its further movement, characterized in that the cap (48) in the bottom (58) , 70) mounted pressure piece (60) has a smaller diameter than the piston (46) connected to the valve needle (26).
2. Einspritzdüse nach Anspruch 1, dadurch gekennzeichnet, daß die Kappe (48) von einer Rückführfeder (52) in Richtung der Öffnungsbewegung der Ventilnadel (26) gegen eine Gehäuseschulter (18) gedrückt ist (Figur 1). 2. Injection nozzle according to claim 1, characterized in that the cap (48) is pressed by a return spring (52) in the direction of the opening movement of the valve needle (26) against a housing shoulder (18) (Figure 1).
3. Einspritzdüse nach Anspruch 1, dadurch gekennzeichnet, daß sich die Kappe (70) über eine vorgespannte Stützfeder (72) an einer Gehäuseschulter (18) abstützt und daß die Vorspannkraft der Stützfeder (72) an einer Gegenschulter (54) des Gehäuses (14) abgefangen ist (Figur 2).3. Injection nozzle according to claim 1, characterized in that the cap (70) is supported by a prestressed support spring (72) on a housing shoulder (18) and in that the biasing force of the support spring (72) on a counter shoulder (54) of the housing (14 ) is intercepted (Figure 2).
4 . Einspritzdüse nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß die in den Dämpfungsraum (62) führenden Drosselkanäle durch die Lagerspiele von Kolben ( 46 ) und Druckstück (60) gebildet sind. 4th Injection nozzle according to one of the preceding claims, characterized in that the throttle ducts leading into the damping space (62) are formed by the bearing clearances of the piston (46) and pressure piece (60).
EP86901817A 1985-05-02 1986-03-26 Fuel injection nozzle for internal combustion engines Expired EP0220207B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3515723 1985-05-02
DE19853515723 DE3515723A1 (en) 1985-05-02 1985-05-02 FUEL INJECTION NOZZLE FOR INTERNAL COMBUSTION ENGINES

Publications (2)

Publication Number Publication Date
EP0220207A1 true EP0220207A1 (en) 1987-05-06
EP0220207B1 EP0220207B1 (en) 1988-06-08

Family

ID=6269597

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EP86901817A Expired EP0220207B1 (en) 1985-05-02 1986-03-26 Fuel injection nozzle for internal combustion engines

Country Status (5)

Country Link
US (1) US4730785A (en)
EP (1) EP0220207B1 (en)
JP (1) JPS62502699A (en)
DE (2) DE3515723A1 (en)
WO (1) WO1986006441A1 (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DK65592D0 (en) * 1992-05-19 1992-05-19 Dysekompagniet I S V Svend End nozzle
GB9301793D0 (en) * 1993-01-29 1993-03-17 Lucas Ind Plc Fuel injection nozzle
US5836521A (en) * 1995-03-09 1998-11-17 Dysekompagniet I/S Valve device with impact member and solenoid for atomizing a liquid
DE19546033A1 (en) * 1995-12-09 1997-06-12 Bosch Gmbh Robert Fuel injection valve for internal combustion engines
GB9802061D0 (en) * 1998-01-31 1998-03-25 Lucas Ind Plc Spring assembly
DE19940558C2 (en) * 1998-09-16 2003-11-20 Siemens Ag Device for delaying the deflection of the nozzle needle of a fuel injector
US6042028A (en) * 1999-02-18 2000-03-28 General Motors Corporation Direct injection fuel injector spray nozzle and method

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Publication number Priority date Publication date Assignee Title
DE2451462A1 (en) * 1974-10-30 1976-05-06 Maschf Augsburg Nuernberg Ag INJECTION VALVE FOR RECEPTACLE COMBUSTION MACHINERY
DE2825982A1 (en) * 1978-06-14 1980-01-03 Bosch Gmbh Robert FUEL INJECTION NOZZLE FOR INTERNAL COMBUSTION ENGINES
DE3120060A1 (en) * 1981-05-20 1982-12-09 Robert Bosch Gmbh, 7000 Stuttgart FUEL INJECTION NOZZLE FOR INTERNAL COMBUSTION ENGINES
DE3220398A1 (en) * 1982-01-26 1983-07-28 Robert Bosch Gmbh, 7000 Stuttgart FUEL INJECTION NOZZLE FOR INTERNAL COMBUSTION ENGINES
DE3246916A1 (en) * 1982-12-18 1984-06-20 Robert Bosch Gmbh, 7000 Stuttgart FUEL INJECTION NOZZLE FOR INTERNAL COMBUSTION ENGINES
DE3307671A1 (en) * 1983-03-04 1984-09-06 Robert Bosch Gmbh, 7000 Stuttgart FUEL INJECTION NOZZLE FOR INTERNAL COMBUSTION ENGINES

Non-Patent Citations (1)

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Title
See references of WO8606441A1 *

Also Published As

Publication number Publication date
DE3660290D1 (en) 1988-07-14
JPS62502699A (en) 1987-10-15
DE3515723A1 (en) 1986-11-06
US4730785A (en) 1988-03-15
EP0220207B1 (en) 1988-06-08
WO1986006441A1 (en) 1986-11-06

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