EP0153490B1 - Constant-pressure delivery valve for fuel injection pumps - Google Patents

Constant-pressure delivery valve for fuel injection pumps Download PDF

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Publication number
EP0153490B1
EP0153490B1 EP84116229A EP84116229A EP0153490B1 EP 0153490 B1 EP0153490 B1 EP 0153490B1 EP 84116229 A EP84116229 A EP 84116229A EP 84116229 A EP84116229 A EP 84116229A EP 0153490 B1 EP0153490 B1 EP 0153490B1
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EP
European Patent Office
Prior art keywords
valve
seat body
seat
passage
valve seat
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Expired
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EP84116229A
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German (de)
French (fr)
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EP0153490A1 (en
Inventor
Walter Ing. Häfele
Reinhard Dipl.-Ing. Schwartz
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Robert Bosch GmbH
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Robert Bosch GmbH
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Publication of EP0153490A1 publication Critical patent/EP0153490A1/en
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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
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
    • F02M59/46—Valves
    • F02M59/462—Delivery valves

Definitions

  • the invention relates to a constant pressure valve for fuel injection pumps of the type specified in the preamble of claim 1.
  • Such constant pressure valves control the fuel delivery of the injection pump to an injection nozzle and, on the other hand, are intended to prevent the formation of pressure waves in the pressure line system leading from the pump work space to the injection nozzle when the injection nozzle is closed, which are the cause of so-called post-spraying and cavitation in the pressure line system, and to maintain a predetermined stand pressure .
  • a known constant pressure valve of the generic type (US-A-2 214 364, Figures 4 and 5) has a first, disk-shaped valve seat body which carries a resilient, annular valve plate in the form of a spring plate with a central passage on a central pin.
  • the valve plate lies with an edge of its passage on the first valve seat of the first valve seat body and an outer edge of the valve plate cooperates with a second valve seat located on the pipe connection part of the injection pump, which has the disadvantage that to check the function of the constant pressure valve that the connection of the connecting piece leading to the injection nozzle leading pressure line must be checked together with the first valve seat body and the valve plate in one device. This means that when the valve is replaced or readjusted, the connector of the injection pump must also be replaced.
  • this known constant pressure valve does not have a backflow throttle required for the targeted tuning and damping of the fuel flowing back.
  • the first valve seat body which is in the installed state of the constant pressure valve on the delivery side of the injection pump, that is to say is adjacent to the pressure line system facing away from the pump work space, has a pin projecting towards the second valve seat body which, on the one hand, serves to center the annular valve plate and, on the other hand, forms a backflow throttle with the passage of the valve plate, for which purpose the valve plate surrounds the pin with play.
  • This game changes during the stroke movement of the valve plate, so that the size of the backflow throttle can therefore only be reproduced within wide tolerances and there are considerable variations in the specimen.
  • the fuel flows during fuel delivery through a central opening in the second valve seat body and through a large number of small, inclined bores in the first valve seat body to the pressure line system. Since the inclined bores must open outside the valve plate, they are at a relatively large radial distance from the valve axis. This means that there are relatively large dead spaces on the delivery side of the constant pressure valve as a harmful dead volume, which has an unfavorable effect on achieving a high injection pressure.
  • the object of the invention is the formation of a compact, easy-to-manufacture and outside of the fuel injection pump to be checked in its function, the pressure relief valve, in particular the reliability and uniform pressure relief of the fuel located in the line leading to the injector is in the foreground, which is why the design of the backflow throttle containing backflow channel is of particular importance, since the backflow throttle must be able to be manufactured and tested in a tightly tolerated manner.
  • the constant pressure valve according to the invention with the characterizing features of claim 1 has the advantage that the backflow throttle can be drilled precisely and closely.
  • the specimen scatter is extremely low. Due to the short axial length of the passage channels, there are only very small dead spaces. Larger injection pressures can thus be achieved with the valve according to the invention.
  • the disc-like design of the second valve seat body which is known per se from DE-A-18 15 254 already cited, makes it possible to test the complete valve assembly with both valve seat bodies and the valve plate outside the injection pump, without also including its connector.
  • the two valve seat bodies are held together by the high-pressure seal specified in the characterizing part of claim 2 and can thus also be used outside the injection pump without additional devices be checked.
  • the features of claims 2 or 3 or 4 provide the advantage of a complete, transport-safe structural unit for easier installation in the pump housing of the fuel injection pump.
  • the high-pressure seal also serves as mechanical cohesion, as a transport lock and as a seal in the pump housing. In the installed state, the constant pressure valve closes the open end of the cylinder liner with the pump piston sliding therein in a liquid-tight manner and delimits the pump work space.
  • the high-pressure seal also assumes the function of a centering ring when the constant pressure valve is placed on the cylinder liner of the fuel injection pump.
  • the constant pressure valve for a fuel injection pump which can be seen in longitudinal section in FIG.
  • the valve plate 14 is centered in a recess 15 on the end face 10a of the first valve seat body 10.
  • the valve plate 14 is annular and resilient and is realized here as a plate spring (spring plate) with a central passage 17.
  • the valve plate 14 bears with an edge 17a of the passage 17 against the first valve seat 12 of the first valve seat body 10 and with an outer edge 14a against the second valve seat 13 of the second valve seat body 11.
  • first valve seat body 10 Arranged in the first valve seat body 10 are a plurality of passage channels 18, 19 which are offset radially outward from the first valve seat 12 and are evenly offset from one another in the circumferential direction.
  • One of these passage channels is provided with a backflow throttle 19a through which the second valve seat body 11 flows.
  • the passage channels 18 and 19 with backflow throttle 19a end at the base 20 of the recess 15, the backflow throttle 19a being connected on the input side to an inlet groove 21 which forms a fuel passage 16 and which runs continuously in the cylinder wall of the recess 15 and in the base 20 thereof.
  • the passage channels 18 and 19 open into a flat, pot-shaped recess 23.
  • the second valve seat body 11 has a central through bore 24 which is substantially aligned with the central passage 17 of the valve plate 14.
  • the second valve seat 13 is offset to the outside with respect to the first valve seat 12, the passage channels 18 and 19 ending freely in the recess 15 between the two valve seats 12, 13.
  • the two valve seat bodies 10, 11 are connected to one another by means of a high-pressure seal 25 surrounding the circumference of the valve seat bodies 10, 11.
  • the high-pressure seal 25 overlaps the free end face 27 of the second valve seat body 11 with a flanging edge 26 and is fastened to the outer circumference of the first valve seat body 10 by means of beads 28.
  • the high-pressure seal 25 projects with a protrusion dimension and here forms a one-piece centering collar 29. In the installed state, the centering collar 29 overlaps a cylinder liner 30 shown in broken lines in FIG. 1 on the outer circumference.
  • the end face 22 of the first valve seat body 10 rests on an end face 30a of the cylinder liner 30 and, together with a pump piston 31 that slides axially in the cylinder liner 30, delimits a pump working chamber 32 of the fuel injection pump.
  • the constant pressure valve is pressed against the end face of the cylinder liner 30 by a connecting piece 33, also shown in broken lines in FIG. 1, which can be screwed into a bore in the pump housing, the high-pressure seal 25 ensuring a liquid-tight cover.
  • the connecting piece 33 has, in a known manner, a central bore 34 which is connected to an injection nozzle via a pressure line.
  • valve plate 14 During the pressure stroke of the pump piston 31, the valve plate 14 lifts with its surrounding area at the passage 17 from the first valve seat 12 on the first valve seat body 10, so that fuel can flow from the pump working space 32 via the passage channels 18, 19 to the central through bore 24 and from here via the Central bore 34 is promoted to the injector. After the delivery stroke has ended, the valve plate 14 rests on the first valve seat 12 on the first valve seat body 10, so that no fuel can flow back. However, since a high pressure occurs in the pressure line and in the central bore 34 as a result of the pressure waves which form when the injection nozzle closes, the outer edge 14a of the valve plate 14 is lifted off the second valve seat 13 on the second valve seat body 11.
  • the fuel can now flow back out of the central bore 34 via the central through bore 24, the inlet groove 21 and the backflow throttle 19a into the pump work chamber 32.
  • the pressure builds up at the closing pressure of the valve plate 14 on its second valve seat 13.
  • the backflow throttle 19a prevents excessive relief at high speed and fluttering of the valve plate 14.
  • the passage channels 18 are largely covered by the plate spring 14, so that only the backflow throttle 19a comes into effect.
  • the constant pressure valve according to the exemplary embodiment in FIG. 2 is largely identical to the constant pressure valve in FIG. 1, so that the same components are identified by the same reference numerals, which, however, are provided with a comma to distinguish them.
  • the two constant pressure valves differ only in the design of the high pressure seal 25 or 25 '.
  • the high pressure seal 25 ' encloses the two valve seat bodies 10' and 11 'facing one another on the outer circumference with their end faces 10a', 11a '.
  • the high-pressure seal 25 ' overlaps both the free end face 22' of the first valve seat body 10 'and the free end face 27' of the second valve seat body 11 ', each with a flange edge 26' and 35 '.
  • the structure and mode of operation of this constant pressure valve according to FIG. 2 is otherwise identical to that described for FIG.

Description

Stand der TechnikState of the art

Die Erfindung betrifft ein Gleichdruckventil für Kraftstoffeinspritzpumpen der im Oberbegriff des Patentanspruchs 1 angegebenen Gattung.The invention relates to a constant pressure valve for fuel injection pumps of the type specified in the preamble of claim 1.

Solche Gleichdruckventile steuern einerseits die Kraftstofförderung der Einspritzpumpe zu einer Einspritzdüse und sollen andererseits die Entstehung von Druckwellen in dem von dem Pumpenarbeitsraum zur Einspritzdüse führenden Druckleitungssystem beim Schließen der Einspritzdüse verhindern, die Ursache für sogenannte Nachspritzer und von Kavitationserscheinungen im Druckleitungssystem sind, und einen vorgegebenen Standdruck aufrechterhalten.Such constant pressure valves on the one hand control the fuel delivery of the injection pump to an injection nozzle and, on the other hand, are intended to prevent the formation of pressure waves in the pressure line system leading from the pump work space to the injection nozzle when the injection nozzle is closed, which are the cause of so-called post-spraying and cavitation in the pressure line system, and to maintain a predetermined stand pressure .

Ein bekanntes Gleichdruckventil der gattungsgemäßen Bauart (US-A-2 214 364, Figuren 4 und 5) weist einen ersten, scheibenartig ausgebildeten Ventilsitzkörper auf, der auf einem zentrischen Stift eine federnde, ringförmige Ventilplatte in Form einer Federplatte mit zentralem Durchlaß trägt. Die Ventilplatte liegt dabei mit einem Rand ihres Durchlasses an dem ersten Ventilsitz des ersten Ventilsitzkörpers an und ein Außenrand der Ventilplatte arbeitet mit einem am Rohranschlußteil der Einspritzpumpe befindlichen zweiten Ventilsitz zusammen, was den Nachteil hat, daß zur Überprüfung der Funktion des Gleichdruckventils das dem Anschluß der zur Einspritzdüse führenden Druckleitung dienende Anschlußstück zusammen mit dem ersten Ventilsitzkörper und der Ventilplatte in einer Vorrichtung geprüft werden müssen. Das bedeutet, daß beim Austausch oder bei einer Neueinstellung des Ventils auch das Anschlußstück der Einspritzpumpe mit ausgetauscht werden muß. Außerdem weist dieses bekannte Gleichdruckventil keine zur gezielten Abstimmung und Dämpfung des zurückströmenden Kraftstoffes erforderliche Rückströmdrossel auf.A known constant pressure valve of the generic type (US-A-2 214 364, Figures 4 and 5) has a first, disk-shaped valve seat body which carries a resilient, annular valve plate in the form of a spring plate with a central passage on a central pin. The valve plate lies with an edge of its passage on the first valve seat of the first valve seat body and an outer edge of the valve plate cooperates with a second valve seat located on the pipe connection part of the injection pump, which has the disadvantage that to check the function of the constant pressure valve that the connection of the connecting piece leading to the injection nozzle leading pressure line must be checked together with the first valve seat body and the valve plate in one device. This means that when the valve is replaced or readjusted, the connector of the injection pump must also be replaced. In addition, this known constant pressure valve does not have a backflow throttle required for the targeted tuning and damping of the fuel flowing back.

Bei einem anderen Gleichdruckventil ähnlicher Bauart (DE-A-18 15 254) weist allerdings der erste Ventilsitzkörper, der im Einbauzustand des Gleichdruckventils auf der Förderseite der Einspritzpumpe liegt, also vom Pumpenarbeitsraum abgekehrt an dem Druckleitungssystem angrenzt, einen zum zweiten Ventilsitzkörper hin vorspringenden Zapfen auf, der einerseits zur Zentrierung der ringförmigen Ventilplatte dient und andererseits mit dem Durchlaß der Ventilplatte eine Rückströmdrossel bildet, wozu die Ventilplatte den Zapfen mit Spiel umgibt. Dieses Spiel ändert sich bei der Hubbewegung der Ventilplatte, so daß die Größe der Rückströmdrossel daher nur in weiten Toleranzen reproduzierbar ist und sich erhebliche Exemplarstreuungen ergeben. Bei diesem bekannten Ventil fließt während der Kraftstoffförderung der Kraftstoff über eine Zentralöffnung im zweiten Ventilsitzkörper und durch sehr viele kleine schräggestellte Bohrungen im ersten Ventilsitzkörper zum Druckleitungssystem. Da die schräggestellten Bohrungen außerhalb der Ventilplatte münden müssen, weisen sie einen relativ großen radialen Abstand von der Ventilachse auf. Damit sind auf der Förderseite des Gleichdruckventils relativ große Toträume als schädliches Totvolumen vorhanden, was sich ungünstig auf die Erzielung eines hohen Einspritzdruckes auswirkt.In the case of another constant pressure valve of a similar type (DE-A-18 15 254), however, the first valve seat body, which is in the installed state of the constant pressure valve on the delivery side of the injection pump, that is to say is adjacent to the pressure line system facing away from the pump work space, has a pin projecting towards the second valve seat body which, on the one hand, serves to center the annular valve plate and, on the other hand, forms a backflow throttle with the passage of the valve plate, for which purpose the valve plate surrounds the pin with play. This game changes during the stroke movement of the valve plate, so that the size of the backflow throttle can therefore only be reproduced within wide tolerances and there are considerable variations in the specimen. In this known valve, the fuel flows during fuel delivery through a central opening in the second valve seat body and through a large number of small, inclined bores in the first valve seat body to the pressure line system. Since the inclined bores must open outside the valve plate, they are at a relatively large radial distance from the valve axis. This means that there are relatively large dead spaces on the delivery side of the constant pressure valve as a harmful dead volume, which has an unfavorable effect on achieving a high injection pressure.

Aufgabe der Erfindung ist nummehr die Bildung eines kompakten, einfach zu fertigenden und außerhalb der Kraftstoffeinspritzpumpe in seiner Funktion zu überprüfenden Gleichdruckentlastungsventils, wobei insbesondere die Funktionssicherheit und gleichmäßige Druckentlastung des in der zur Einspritzdüse führenden Leitung befindlichen Kraftstoffes im Vordergrund steht, weshalb der Ausgestaltung des die Rückströmdrossel enthaltenden Rückströmkanals eine besondere Bedeutung zukommt, da die Rückströmdrossel engtoleriert herstell- und prüfbar sein muß.The object of the invention is the formation of a compact, easy-to-manufacture and outside of the fuel injection pump to be checked in its function, the pressure relief valve, in particular the reliability and uniform pressure relief of the fuel located in the line leading to the injector is in the foreground, which is why the design of the backflow throttle containing backflow channel is of particular importance, since the backflow throttle must be able to be manufactured and tested in a tightly tolerated manner.

Vorteile der ErfindungAdvantages of the invention

Das erfindungsgemäße Gleichdruckventil mit den kennzeichnenden Merkmalen des Patentanspruchs 1 hat demgegenüber den Vorteil, daß die Rückströmdrossel exakt und eng toleriert gebohrt werden kann. Die Exemplarstreuungen sind extrem gering. Durch die geringe axiale Länge der Durchlaßkanäle sind nur sehr kleine Toträume vorhanden. Mit dem erfindungsgemäßen Ventil können damit größere Einspritzdrücke erzielt werden. Die scheibenartige Ausbildung des zweiten Ventilsitzkörpers, die an sich aus der bereits zitierten DE-A-18 15 254 bekannt ist, ermöglicht es, die komplette Ventilbaugruppe mit beiden Ventilsitzkörpern und der Ventilplatte außerhalb der Einspritzpumpe zu prüfen, ohne deren Anschlußstück auch mit einzubeziehen. Obwohl aus der GB-A-2 065 791 ein als Rückströmdrossel ausgebildeter Durchlaßkanal an sich bekannt ist, löst erst die erfindungsgemäße Kombination aller im kennzeichnenden Teil des Patentanspruchs 1 aufgeführten Merkmale die erfindungsgemäße Aufgabe, und die den Kraftstoffdurchlaß bildende Nut, die ständig mit der Rückströmdrossel in Verbindung steht, gewährleistet, daß beim Ende der Einspritzung und bei durch den rückströmenden Kraftstoff an die übrigen Rückströmkanäle angelegter Ventilplatte der Kraftstoff unter Umgehung des Außenrandes der Ventilplatte mit Hilfe der diese Umgehung bildenden Nut zur Rückströmdrossel und durch diese hindurch zum Pumpenarbeitsraum zurückfließen kann.The constant pressure valve according to the invention with the characterizing features of claim 1 has the advantage that the backflow throttle can be drilled precisely and closely. The specimen scatter is extremely low. Due to the short axial length of the passage channels, there are only very small dead spaces. Larger injection pressures can thus be achieved with the valve according to the invention. The disc-like design of the second valve seat body, which is known per se from DE-A-18 15 254 already cited, makes it possible to test the complete valve assembly with both valve seat bodies and the valve plate outside the injection pump, without also including its connector. Although from GB-A-2 065 791 a passage channel designed as a backflow throttle is known per se, it is only the combination according to the invention of all the features listed in the characterizing part of patent claim 1 that achieves the object according to the invention, and the groove forming the fuel passage, which is constantly connected to the backflow throttle is connected, ensures that at the end of the injection and with the valve plate applied by the returning fuel to the other return channels, the fuel can bypass the outer edge of the valve plate with the help of this bypass groove to the backflow throttle and through this back to the pump work space.

Vorteilhafte Weiterbildungen und Verbesserungen des im Patentanspruch 1 angegebenen Gleichdruckventils sind den Unteransprüchen zu entnehmen. So werden die beiden Ventilsitzkörper durch die im Kennzeichenteil des Anspruchs 2 angegebene Hochdruckdichtung zusammengehalten und können so auch außerhalb der Einspritzpumpe ohne zusätzliche Vorrichtungen geprüft werden. Außerdem ergibt sich bei einer kompakten Bauweise des Gleichdruckventils durch die Merkmale der Ansprüche 2 bzw. 3 oder 4 der Vorteil einer kompletten, transportsicheren Baueinheit für einen erleichterten Einbau in das Pumpengehäuse der Kraftstoffeinspritzpumpe. Die Hochdruckdichtung dient zugleich dem mechanischen Zusammenhalt, als Transportsicherung und als Dichtung im Pumpengehäuse. Im Einbauzustand schließt dabei das Gleichdruckventil die offene Stirnseite der Zylinderbüchse mit dem darin gleitenden Pumpenkolben flüssigkeitsdicht ab und begrenzt den Pumpenarbeitsraum. Mit den kennzeichnenden Merkmalen des Anspruchs 5 übernimmt die Hochdruckdichtung auch noch die Funktion eines Zentrierringes beim Aufsetzen des Gleichdruckventils auf der Zylinderbüchse der Kraftstoffeinspritzpumpe.Advantageous further developments and improvements of the constant pressure valve specified in claim 1 can be found in the subclaims. Thus, the two valve seat bodies are held together by the high-pressure seal specified in the characterizing part of claim 2 and can thus also be used outside the injection pump without additional devices be checked. In addition, in the case of a compact design of the constant pressure valve, the features of claims 2 or 3 or 4 provide the advantage of a complete, transport-safe structural unit for easier installation in the pump housing of the fuel injection pump. The high-pressure seal also serves as mechanical cohesion, as a transport lock and as a seal in the pump housing. In the installed state, the constant pressure valve closes the open end of the cylinder liner with the pump piston sliding therein in a liquid-tight manner and delimits the pump work space. With the characterizing features of claim 5, the high-pressure seal also assumes the function of a centering ring when the constant pressure valve is placed on the cylinder liner of the fuel injection pump.

Zeichnungdrawing

Die Erfindung ist anhand von in der Zeichnung dargestellten Ausführungsbeispielen in der nachfolgenden Beschreibung näher erläutert. Es zeigen :

  • Figuren 1 und 2 jeweils einen Längsschnitt eines Gleichdruckventils gemäß einem ersten und zweiten Ausführungsbeispiel,
  • Figur 3 einen Querschnitt einer Ventilplatte des Gleichdruckventils in Figur 1.
The invention is explained in more detail in the following description with reference to exemplary embodiments shown in the drawing. Show it :
  • FIGS. 1 and 2 each show a longitudinal section of a constant pressure valve according to a first and second exemplary embodiment,
  • FIG. 3 shows a cross section of a valve plate of the constant pressure valve in FIG. 1.

Beschreibung der AusführungsbeispieleDescription of the embodiments

Das in Figur 1 im Längsschnitt zu sehende Gleichdruckventil für eine Kraftstoffeinspritzpumpe weist zwei mit ihren Stirnseiten 10a, 11a aneinanderliegende Ventilsitzkörper 10, 11 mit jeweils einem Ventilsitz 12, 13 für eine dazwischenliegende Ventilplatte 14 auf. Die Ventilplatte 14 ist in einer Ausnehmung 15 auf der Stirnseite 10a des ersten Ventilsitzkörpers 10 zentriert. Wie aus Figur 3 ersichtlich, ist die Ventilplatte 14 ringförmig und federnd ausgebildet und ist hier als Tellerfeder (Federplatte) mit einem zentralen Durchlaß 17 realisiert. Die Ventilplatte 14 liegt mit einem Rand 17a des Durchlasses 17 an dem ersten Ventilsitz 12 des ersten Ventilsitzkörpers 10 und mit einem Außenrand 14a an dem zweiten Ventilsitz 13 des zweiten Ventilsitzkörpers 11 an.The constant pressure valve for a fuel injection pump, which can be seen in longitudinal section in FIG. The valve plate 14 is centered in a recess 15 on the end face 10a of the first valve seat body 10. As can be seen from Figure 3, the valve plate 14 is annular and resilient and is realized here as a plate spring (spring plate) with a central passage 17. The valve plate 14 bears with an edge 17a of the passage 17 against the first valve seat 12 of the first valve seat body 10 and with an outer edge 14a against the second valve seat 13 of the second valve seat body 11.

Im ersten Ventilsitzkörper 10 sind mehrere im Radialabstand zum ersten Ventilsitz 12 nach außen hin versetzte Durchlaßkanäle 18, 19 angeordnet, die in Umfangsrichtung gegeneinander gleichmäßig versetzt sind. Einer dieser Durchlaßkanäle ist mit einer Rückströmdrossel 19a versehen, die von dem zweiten Ventilsitzkörper 11 her durchströmt wird. Die Durchlaßkanäle 18 und 19 mit Rückströmdrossel 19a enden am Grund 20 der Ausnehmung 15, wobei die Rückströmdrossel 19a mit einer einen Kraftstoffdurchlaß 16 bildenden Einlaufnut 21 eingangsseitig in Verbindung steht, die durchgehend in der Zylinderwandung der Ausnehmung 15 und in deren Grund 20 verläuft. Auf der gegenüberliegenden Stirnseite 22 des ersten Ventilsitzkörpers 10 münden die Durchlaßkanäle 18 und 19 in einer flachen, topfförmigen Vertiefung 23.Arranged in the first valve seat body 10 are a plurality of passage channels 18, 19 which are offset radially outward from the first valve seat 12 and are evenly offset from one another in the circumferential direction. One of these passage channels is provided with a backflow throttle 19a through which the second valve seat body 11 flows. The passage channels 18 and 19 with backflow throttle 19a end at the base 20 of the recess 15, the backflow throttle 19a being connected on the input side to an inlet groove 21 which forms a fuel passage 16 and which runs continuously in the cylinder wall of the recess 15 and in the base 20 thereof. On the opposite end face 22 of the first valve seat body 10, the passage channels 18 and 19 open into a flat, pot-shaped recess 23.

Der zweite Ventilsitzkörper 11 weist eine zentrale Durchgangsbohrung 24 auf, die im wesentlichen mit dem zentralen Durchlaß 17 der Ventilplatte 14 fluchtet. Der zweite Ventilsitz 13 ist gegenüber dem ersten Ventilsitz 12 nach außen versetzt, wobei die Durchlaßkanäle 18 und 19 zwischen den beiden Ventilsitzen 12, 13 in der Ausnehmung 15 frei enden.The second valve seat body 11 has a central through bore 24 which is substantially aligned with the central passage 17 of the valve plate 14. The second valve seat 13 is offset to the outside with respect to the first valve seat 12, the passage channels 18 and 19 ending freely in the recess 15 between the two valve seats 12, 13.

Die beiden Ventilsitzkörper 10, 11 sind mittels einer den Umfang der Ventilsitzkörper 10, 11 umschließenden Hochdruckdichtung 25 miteinander verbunden. Die Hochdruckdichtung 25 übergreift mit einem Umbördelungsrand 26 die freie Stirnseite 27 des zweiten Ventilsitzkörpers 11 und ist mittels Sicken 28 am Außenumfang des ersten Ventilsitzkörpers 10 befestigt. Auf der freien Stirnseite 22 des ersten Ventilsitzkörpers 10 steht die Hochdruckdichtung 25 mit Überstandsmaß über und bildet hier einen einstückigen Zentrierbund 29. Im Einbauzustand übergreift der Zentrierbund 29 eine in Fig. 1 strichliniert dargestellte Zylinderbüchse 30 am Außenumfang. Die Stirnseite 22 des ersten Ventilsitzkörpers 10 liegt auf einer Stirnseite 30a der Zylinderbüchse 30 auf und begrenzt zusammen mit einem in der Zylinderbüchse 30 axial gleitenden Pumpenkolben 31 einen Pumpenarbeitsraum 32 der Kraftstoffeinspritzpumpe. Das Gleichdruckventil wird durch ein in Fig. 1 ebenfalls strichliniert dargestelltes Anschlußstück 33, das in einer Bohrung des Pumpengehäuses verschraubt werden kann, gegen die Stirnseite der Zylinderbüchse 30 gepreßt, wobei die Hochdruckdichtung 25 eine flüssigkeitsdichte Abdeckung gewährleistet. Das Anschlußstück 33 weist in bekannter Weise eine Zentralbohrung 34 auf, die über eine Druckleitung mit einer Einspritzdüse verbunden ist.The two valve seat bodies 10, 11 are connected to one another by means of a high-pressure seal 25 surrounding the circumference of the valve seat bodies 10, 11. The high-pressure seal 25 overlaps the free end face 27 of the second valve seat body 11 with a flanging edge 26 and is fastened to the outer circumference of the first valve seat body 10 by means of beads 28. On the free end face 22 of the first valve seat body 10, the high-pressure seal 25 projects with a protrusion dimension and here forms a one-piece centering collar 29. In the installed state, the centering collar 29 overlaps a cylinder liner 30 shown in broken lines in FIG. 1 on the outer circumference. The end face 22 of the first valve seat body 10 rests on an end face 30a of the cylinder liner 30 and, together with a pump piston 31 that slides axially in the cylinder liner 30, delimits a pump working chamber 32 of the fuel injection pump. The constant pressure valve is pressed against the end face of the cylinder liner 30 by a connecting piece 33, also shown in broken lines in FIG. 1, which can be screwed into a bore in the pump housing, the high-pressure seal 25 ensuring a liquid-tight cover. The connecting piece 33 has, in a known manner, a central bore 34 which is connected to an injection nozzle via a pressure line.

Die Wirkungsweise des Gleichdruckventils im Einbauzustand ist wie folgt :The principle of operation of the constant pressure valve when installed is as follows:

Beim Druckhub des Pumpenkolbens 31 hebt die Ventilplatte 14 mit ihrem Umgebungsbereich am Durchlaß 17 von dem ersten Ventilsitz 12 am ersten Ventilsitzkörper 10 ab, so daß Kraftstoff aus dem Pumpenarbeitsraum 32 über die Durchlaßkanäle 18, 19 zur zentralen Durchgangsbohrung 24 strömen kann und von hier über die Zentralbohrung 34 zur Einspritzdüse gefördert wird. Nach Beendigung des Förderhubs legt sich die Ventilplatte 14 wieder auf den ersten Ventilsitz 12 am ersten Ventilsitzkörper 10 auf, so daß kein Kraftstoff zurückfließen kann. Da Jedoch in der Druckleitung und in der Zentralbohrung 34 infolge der sich beim Schließen der Einspritzdüse ausbildenden Druckwellen ein hoher Druck auftritt, wird der Außenrand 14a der Ventilplatte 14 von dem zweiten Ventilsitz 13 am zweiten Ventilsitzkörper 11 abgehoben. Der Kraftstoff kann nunmehr aus der Zentralbohrung 34 über die zentrale Durchgangsbohrung 24, die Einlaufnut 21 und die Rückströmdrossel 19a in den Pumpenarbeitsraum 32 zurückfließen. Der Druck baut sich bis zum Schließdruck der Ventilplatte 14 an ihrem zweiten Ventilsitz 13 ab. Die Rückströmdrossel 19a verhindert eine zu starke Entlastung bei hoher Drehzahl und ein Flattern der Ventilplatte 14. Während des Entlastungsvorgangs sind die Durchlaßkanäle 18 von der Tellerfeder 14 weitgehend abgedeckt, so daß nur die Rückströmdrossel 19a zur Wirkung kommt.During the pressure stroke of the pump piston 31, the valve plate 14 lifts with its surrounding area at the passage 17 from the first valve seat 12 on the first valve seat body 10, so that fuel can flow from the pump working space 32 via the passage channels 18, 19 to the central through bore 24 and from here via the Central bore 34 is promoted to the injector. After the delivery stroke has ended, the valve plate 14 rests on the first valve seat 12 on the first valve seat body 10, so that no fuel can flow back. However, since a high pressure occurs in the pressure line and in the central bore 34 as a result of the pressure waves which form when the injection nozzle closes, the outer edge 14a of the valve plate 14 is lifted off the second valve seat 13 on the second valve seat body 11. The fuel can now flow back out of the central bore 34 via the central through bore 24, the inlet groove 21 and the backflow throttle 19a into the pump work chamber 32. The pressure builds up at the closing pressure of the valve plate 14 on its second valve seat 13. The backflow throttle 19a prevents excessive relief at high speed and fluttering of the valve plate 14. During the relief process, the passage channels 18 are largely covered by the plate spring 14, so that only the backflow throttle 19a comes into effect.

Das Gleichdruckventil gemäß dem Ausführungsbeispiel in Fig. 2 ist weitgehend identisch mit dem Gleichdruckventil in Fig. 1, so daß gleiche Bauteile mit gleichen Bezugszeichen gekennzeichnet sind, die jedoch zur Unterscheidung mit einem Beistrich versehen sind. Die beiden Gleichdruckventile unterscheiden sich lediglich in der Ausbildung der Hochdruckdichtung 25 bzw. 25'. Wie aus Figur 2 ersichtlich ist, umschließt hier wiederum die Hochdruckdichtung 25' die beiden mit ihren Stirnseiten 10a', 11a' einander zugewandte Ventilsitzkörper 10' und 11' am Außenumfang. Die Hochdruckdichtung 25' übergreift mit jeweils einem Umbördelungsrand 26' und 35' sowohl die freie Stirnseite 22' des ersten Ventilsitzkörpers 10' als auch die freie Stirnseite 27' des zweiten Ventilsitzkörpers 11'. Aufbau und Wirkungsweise dieses Gleichdruckventils gemäß Figur 2 ist ansonsten identisch wie zu Figur 1 beschrieben.The constant pressure valve according to the exemplary embodiment in FIG. 2 is largely identical to the constant pressure valve in FIG. 1, so that the same components are identified by the same reference numerals, which, however, are provided with a comma to distinguish them. The two constant pressure valves differ only in the design of the high pressure seal 25 or 25 '. As can be seen from FIG. 2, here again the high pressure seal 25 'encloses the two valve seat bodies 10' and 11 'facing one another on the outer circumference with their end faces 10a', 11a '. The high-pressure seal 25 'overlaps both the free end face 22' of the first valve seat body 10 'and the free end face 27' of the second valve seat body 11 ', each with a flange edge 26' and 35 '. The structure and mode of operation of this constant pressure valve according to FIG. 2 is otherwise identical to that described for FIG.

Claims (5)

1. Constant pressure-valve for fuel injection pumps, with a resilient annular valve plate (14) in the form of a spring plate with a central passage (17), and with two valve-seat bodies (10; 11) resting against one another, each with a valve seat (12, 13) for the valve plate (14) which is located between them and which rests by means of one edge (17a) of the passage (17) against the first valve seat (12) of the first valve-seat body (10) and by means of an outer edge (14a) against the second valve seat (13) of the second valve-seat body (11), the first valve-seat body (10) having at least two continuous passage channels (18, 19) extending axially in the first valve-seat body (10) between the first and second valve seats (12, 13) and offset relative to one another in the peripheral direction, and the second valve-seat body (11) having a central through-bore (24), and furthermore the first valve-seat body (10) being made disc-like, being installed facing a pump working space (32) of the fuel injection pump and receiving the valve plate (14) centrally in a circular recess (15) within its end face (10a) facing the second valve-seat body (11), characterized in that the second valve-seat body (11 ; 11') is also made disc-like, in that moreover one of the passage channels (19 ; 19') is equipped with a return-flow throttle (19a ; 19a'), and in that, furthermore, the return-flow throttle (19a; 19a') is constantly in communication with a groove (21 ; 21') which forms a fuel passage (16 ; 16') and starts outside the outer edge (14a) of the valve plate (14 ; 14') and therefore outside the second valve seat (13 ; 13') in the end face (10a, 10a') of the first valve-seat body (10 ; 10') resting against the second valve-seat body (11 ; 11'), and which extends continuously in the cylindrical wall of the recess (15 ; 15') and partially in its bottom (20 ; 20').
2. Valve according to Claim 1, characterized in that the two valve-seat bod ies (10, 11 ; 10', 11') are connected to one another by means of a high-pressure gasket (25 ; 25') surrounding at least the periphery of the valve-seat bodies (10, 11 ; 10', 11').
3. Valve according to Claim 2, characterized in that the high-pressure gasket (25') engages over each of the free end faces (27' ; 22') of the two valve-seat bodies (10', 11') by means of a flanged edge (26', 35').
4. Valve according to Claim 2, characterized in that the high-pressure gasket (25) engages over the free end face (27) of the second valve-seat body (11) by means of a flanged edge (26) and is fastened to the outer periphery of the first valve-seat body (10) by means of beads (28).
5. Valve according to Claim 4, characterized in that the high-pressure gasket (25) projects with excess length beyond the free end face (22) of the first valve-seat body (10) and forms a centering collar (29) for attachment onto a cylinder bush (30) guiding a pump piston (31) in the pump casing of the fuel injection pump.
EP84116229A 1984-02-10 1984-12-22 Constant-pressure delivery valve for fuel injection pumps Expired EP0153490B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE8404021U 1984-02-10
DE8404021U DE8404021U1 (en) 1984-02-10 1984-02-10 Equal pressure valve for fuel injection pumps

Publications (2)

Publication Number Publication Date
EP0153490A1 EP0153490A1 (en) 1985-09-04
EP0153490B1 true EP0153490B1 (en) 1988-05-04

Family

ID=6763407

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84116229A Expired EP0153490B1 (en) 1984-02-10 1984-12-22 Constant-pressure delivery valve for fuel injection pumps

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EP (1) EP0153490B1 (en)
JP (1) JPS60143165U (en)
DE (2) DE8404021U1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB9416784D0 (en) * 1994-08-19 1994-10-12 Lucas Ind Plc Pressure regulation valve

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2214364A (en) * 1937-12-16 1940-09-10 Timken Roller Bearing Co Valve for fuel injection pumps
CH212495A (en) * 1938-08-16 1940-11-30 Messerschmitt Boelkow Blohm Spring plate valve.
DE1815254A1 (en) * 1968-12-18 1970-08-13 Maschf Augsburg Nuernberg Ag Device for equal pressure relief on fuel injection pump pressure lines
DE2949014C2 (en) * 1979-12-06 1984-03-08 Daimler-Benz Ag, 7000 Stuttgart Fuel injection pump for internal combustion engines

Also Published As

Publication number Publication date
DE8404021U1 (en) 1985-06-13
DE3470912D1 (en) 1988-06-09
JPS60143165U (en) 1985-09-21
EP0153490A1 (en) 1985-09-04

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