EP0270519A1 - Pump element of a fuel injection pump for an injection combustion engine - Google Patents

Pump element of a fuel injection pump for an injection combustion engine Download PDF

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Publication number
EP0270519A1
EP0270519A1 EP87890264A EP87890264A EP0270519A1 EP 0270519 A1 EP0270519 A1 EP 0270519A1 EP 87890264 A EP87890264 A EP 87890264A EP 87890264 A EP87890264 A EP 87890264A EP 0270519 A1 EP0270519 A1 EP 0270519A1
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EP
European Patent Office
Prior art keywords
pump
piston
pump piston
suction
radial bores
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Granted
Application number
EP87890264A
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German (de)
French (fr)
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EP0270519B1 (en
Inventor
Theodor Dipl.-Ing. Dr. Stipek
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Robert Bosch AG
Robert Bosch GmbH
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Robert Bosch AG
Robert Bosch GmbH
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Publication of EP0270519A1 publication Critical patent/EP0270519A1/en
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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
    • F02M55/00—Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump F02M37/00
    • F02M55/001—Pumps with means for preventing erosion on fuel discharge
    • 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
    • F02M59/20—Varying fuel delivery in quantity or timing
    • F02M59/24—Varying fuel delivery in quantity or timing with constant-length-stroke pistons having variable effective portion of stroke
    • F02M59/26—Varying fuel delivery in quantity or timing with constant-length-stroke pistons having variable effective portion of stroke caused by movements of pistons relative to their cylinders
    • F02M59/265—Varying fuel delivery in quantity or timing with constant-length-stroke pistons having variable effective portion of stroke caused by movements of pistons relative to their cylinders characterised by the arrangement or form of spill port of spill contour on the piston

Definitions

  • the invention relates to a pump element of a fuel injection pump for injection internal combustion engines, in which the pump piston liner has at least one suction and overflow bore which is ground over by control edges of the pump piston, at least one control edge arranged in the region of the piston end face determining the start of delivery and at least one arranged on the piston jacket. in particular oblique, control edge determines the delivery end and wherein there is a throttled line connection between the working space of the pump piston and the suction and overflow bore during at least part of the pressure stroke of the pump piston.
  • vapor bubbles or cavities form in the suction and overflow bores.
  • the pump piston brings the fuel in the pump's working space to very high pressures of, for example, 1500 bar and more, and at the end of delivery this highly compressed fuel flows into the suction and overflow bore. If no precautions are taken to remove these vapor bubbles, they will implode as a result of the sudden increase in pressure in the suction and overflow bore, causing cavitation and erosion on the wall of the suction and overflow bore and also on the piston skirt and on the control edge.
  • the object of the invention is to counteract such cavitations in the critical area and to increase the intensity of the removal of the vapor bubbles from this critical area.
  • the invention consists essentially in that the throttled line connection is formed by a plurality of radial bores arranged along the control edge that determines the start of delivery, which are connected to the working space of the pump piston and directly on the outer surface of the pump piston in a suction and Overflow bore overlap area of the same. Because radial bores open directly into the outer surface of the pump piston and not into a recess in the piston wall, the fuel, which is branched off from the working area of the pump piston and is under high pressure, enters the suction and overflow bore in the form of a directed jet and is directed through this jet the removal effect exerted on the vapor bubbles is significantly improved.
  • the arrangement of a plurality of radial bores along the control edge which determines the start of delivery ensures that at least one corresponding throttled fuel jet emerges in each rotational position of the pump piston for conveying away the vapor bubbles in the direction of the suction chamber, the radial direction of the rinsing bores guaranteeing proper removal of the vapor bubbles or cavities . Due to the adjacent radial bores, which have one or more in each rotational position dispensing thin flushing jets into the suction and overflow bore, a flushing curtain or flushing compartments for removing the steam bubbles is achieved with as little distortion of the delivery rate as possible from the pump chamber.
  • the radial bores run approximately parallel to the generatrices of the suction and overflow bores, as a result of which the removal of the jet emerging via the throttled line connection is optimal.
  • the pump piston liner has two diametrically opposite suction and overflow bores, the control edges of the pump piston being arranged centrally symmetrically on both piston sides in order to avoid a one-sided high load on the To avoid pump pistons, which leads to increased wear of the pump piston and the pump piston sleeve.
  • the mouths of the radial bores are arranged centrally symmetrically on both sides of the piston, so that the vapor bubbles are carried away in both suction and overflow bores.
  • the radial bores start from a central bore of the pump piston which is connected to the working space of the pump piston via a throttle cross section. This makes it possible to arrange the bores precisely perpendicular to the axis of the pump piston.
  • the radial bores are expediently spaced apart from one another arranged.
  • the mouths of the radial bores are equally spaced from the control edge. In both cases, the same conditions are created at all rotational positions of the pump piston, and because the throttle cross section is provided in the central bore, the amount of fuel diverted from the working space of the pump piston always remains independent of the number of radial bores connected to the suction and overflow bores equal.
  • the arrangement is preferably such that the mouths of the radial bores are at a distance from the control edge which determines the start of delivery, which is smaller than half the diameter of the suction and overflow bore. It is thereby achieved that the fuel jet emerging through the radial bores already enters the suction and overflow bore at the start of delivery or shortly after the start of delivery, so that there is sufficient time to convey the gas bubbles from the suction and overflow bore.
  • the fuel jet entering the suction and overflow bore also increases the pressure in the suction and overflow bore. However, this pressure increase is less than the pressure increase occurring at the end of the delivery due to the control jet.
  • the gas bubbles still in the suction and overflow bore are therefore brought to a softer imploding, as a result of which the cavitation and erosion phenomena are substantially reduced.
  • radial bores open just below the control edge which determines the start of delivery on the piston jacket surface means that the delivery effect is achieved as soon as delivery begins or just after delivery begins. According to the invention, however, radial bores can also open along the control edge which determines the delivery end and at equal distances therefrom on the lateral surface of the pump piston. As a result, the gas bubbles are conveyed away even at the end of delivery.
  • the design is such that the radial bores open only in those areas of the piston skirt which correspond to a rotational position of the pump piston for large injection quantities. In this way, it is possible to specifically eliminate the vapor bubbles that occur increasingly with large injection quantities and are therefore particularly harmful.
  • the radial holes are only opened for a short period of time by the suction and overflow holes. As a result, the amount of fuel emerging through the radial bores is kept low, so that the delivery characteristics are not significantly influenced.
  • the pump piston 1 is guided in the pump piston sleeve 2 to move up and down.
  • the drive is not shown.
  • two suction and overflow bores 3 are arranged diametrically opposite one another.
  • the upper edge 4 of the pump piston 1 controls the start of delivery by grinding the suction and overflow holes 3 and the oblique control edges 5 control the end of delivery by grinding the suction and overflow holes 3.
  • a central hole 6 is provided in the pump piston, from which radial holes 7 extend. which open directly on the outer surface of the piston 1.
  • the mouths 8 of these radial bores are therefore opened directly through the walls 9 of the suction and overflow bores 3.
  • the central bore 6 is connected via a throttle cross section 10 to the working space 11 of the pump piston 1, so that this throttle 10 acts on all radial bores 7.
  • a directed fuel jet which is indicated by the arrow 12, emerges from the radial bores 7 already at the start of delivery or just after this.
  • This directed fuel jet conveys the gas bubbles 13 away from the suction and overflow bores 3 in the direction of the suction chamber.
  • An arrow 14 indicates the direction of the fuel jet emerging at the end of delivery (FIG. 1a). This sharp fuel jet emerging at the end of delivery is disturbed by the fuel jets emerging through the radial bores 7 and deflected by the walls 9 of the suction and overflow bores.
  • the distance 15 between the orifices 8 of the radial bores 7, which are at the same distance from one another, is very small and the orifices 8 of the bores 7 are arranged at the same distance 15 from the piston face 4, which controls the start of delivery.
  • bores 16 are also arranged along the inclined control edge 5 that determines the end of the conveyor, which bores are all at the same distance 17 from this control edge 5.

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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)

Abstract

1. A pump element of a fuel injection pump for fuel-injected internal combustion engines, in which the pump piston bushing (2) has at least one suction and overflow bore (3) over which control edges (4, 5) of the pump piston (1) slide, at least one control edge (4) disposed in the region of the piston end face determining the start of flow and at least one, in particular oblique control edge (5) disposed on the piston casing determining the end of flow, and, during at least part of the compression stroke of the pump piston (1), a throttled line connexion being present between the operating chamber (11) of the pump piston (1) and the suction and overflow bore (3), the throttled line connexion being formed by a plurality of radial bores (7) which are arranged parallel to the control edge (4) determining the start of flow and which are connected to the operating chamber (11) of the pump piston (1), characterized in that a plurality of radial bores (7) open directly onto the casing surface of the pump piston in an area thereof which slides over the suction and overflow bore (3), the openings (8) of the radial bores (7) are at equal distances from the control edge (4), and the radial bores (7) open into only those areas of the piston casing which correspond to a rotational position of the pump piston (1) for large injection quantities.

Description

Die Erfindung bezieht sich auf ein Pumpenelement einer Brennstoffeinspritzpumpe für Einspritzbrennkraftmaschinen, bei welchem die Pumpenkolbenbüchse wenigstens eine Saug- und Überströmbohrung aufweist, die durch Steuerkanten des Pumpen­kolbens überschliffen wird, wobei wenigstens eine im Bereich der Kolbenstirnfläche angeordnete Steuerkante den Förderbe­ginn und wenigstens eine am Kolbenmantel angeordnete, ins­besondere schräge, Steuerkante das Förderende bestimmt und wobei während wenigstens eines Teiles des Druckhubes des Pumpenkolbens eine gedrosselte Leitungsverbindung zwischen dem Arbeitsraum des Pumpenkolbens und der Saug- und Über­strömbohrung besteht.The invention relates to a pump element of a fuel injection pump for injection internal combustion engines, in which the pump piston liner has at least one suction and overflow bore which is ground over by control edges of the pump piston, at least one control edge arranged in the region of the piston end face determining the start of delivery and at least one arranged on the piston jacket. in particular oblique, control edge determines the delivery end and wherein there is a throttled line connection between the working space of the pump piston and the suction and overflow bore during at least part of the pressure stroke of the pump piston.

Durch den plötzlichen Abschluß der Saug- und Überströmbohrung bei Förderbeginn bilden sich Dampfblasen bzw. Hohlräume in der Saug- und Überströmbohrung. Durch den Pumpenkolben wird der Kraftstoff im Arbeitsraum der Pumpe auf sehr hohe Drücke von beispielsweise 1500 bar und auch mehr gebracht und bei Förderende strömt dieser hochkomprimierte Kraftstoff in die Saug- und Überströmbohrung. Wenn keine Vorsorge für die Wegförderung dieser Dampfblasen getroffen wird, implodieren dieselben infolge der plötzlichen Drucksteigerung in der Saug- und Überströmbohrung und es werden dadurch Kavitationen und Erosionen an der Wandung der Saug- und Überströmbohrung und auch am Kolbenmantel und an der Steuerkante verursacht. Aus der DE-OS 28 07 808 ist es bekannt geworden, Kraftstoff, der im Pumpenarbeitsraum unter Druck gesetzt wurde, über eine Drosselöffnung abzuzweigen und vor dem Aufsteuern der Saug- ­und Überströmbohrung in diese einzuführen, um Dampfblasen aus dieser Saug- und Überströmbohrung wegzufördern. Bei dieser bekannten Anordnung gelangt der abgezweigte Brennstoff in eine Ausnehmung am Kolbenmantel und wird, sobald diese Ausnehmung die Saug- und Überströmbohrung überschleift, in die Saug- und Überströmbohrung gefördert. Hiebei wird aber lediglich der Druck in der Saug- und Überströmbohrung durch den abgezweigten Brennstoff erhöht, wodurch eine Tendenz zur Förderung der Dampfblasen in Richtung zum Saugraum besteht, jedoch ist noch kein sicheres Wegfördern der Dampfblasen aus dem kritischen Bereich der Kolbenwandung und der Steuerkanten der Saug- und Überströmbohrung ermöglicht.Due to the sudden completion of the suction and overflow bores at the start of delivery, vapor bubbles or cavities form in the suction and overflow bores. The pump piston brings the fuel in the pump's working space to very high pressures of, for example, 1500 bar and more, and at the end of delivery this highly compressed fuel flows into the suction and overflow bore. If no precautions are taken to remove these vapor bubbles, they will implode as a result of the sudden increase in pressure in the suction and overflow bore, causing cavitation and erosion on the wall of the suction and overflow bore and also on the piston skirt and on the control edge. From DE-OS 28 07 808 it has become known to branch off fuel which has been pressurized in the pump work space via a throttle opening and to introduce it into the suction and overflow bore in order to convey vapor bubbles away from this suction and overflow bore. In this known arrangement, the branched-off fuel gets into a recess on the piston skirt and, as soon as this recess grinds over the suction and overflow bore, into the suction and overflow drilling promoted. In this case, however, only the pressure in the suction and overflow bores is increased by the branched-off fuel, as a result of which there is a tendency to convey the steam bubbles towards the suction chamber, but there is still no safe removal of the steam bubbles from the critical area of the piston wall and the control edges of the suction - and overflow drilling possible.

Die Erfindung stellt sich zur Aufgabe, solchen Kavitationen im kritischen Bereich entgegenzuwirken und die Intensität der Wegförderung der Dampfblasen aus diesem kritischen Bereich zu erhöhen.The object of the invention is to counteract such cavitations in the critical area and to increase the intensity of the removal of the vapor bubbles from this critical area.

Zur Erfüllung dieser Aufgabe besteht die Erfindung im wesent­lichen darin, daß die gedrosselte Leitungsverbindung von mehreren entlang der den Förderbeginn bestimmenden Steuer­kante angeordneten Radialbohrungen gebildet ist, welche mit dem Arbeitsraum des Pumpenkolbens in Verbindung stehen und unmittelbar an der Mantelfläche des Pumpenkolbens in einem die Saug- und Überströmbohrung überschleifenden Bereich derselben münden. Dadurch, daß Radialbohrungen unmittelbar in die Mantelfläche des Pumpenkolbens münden und nicht in eine Ausnehmung der Kolbenwandung, tritt der aus dem Arbeitsraum des Pumpenkolbens abgezweigte, unter hohem Druck stehende Brennstoff in Form eines gerichteten Strahles in die Saug- ­und Überströmbohrung ein und durch diesen gerichteten Strahl wird die auf die Dampfblasen ausgeübte Wegförderwirkung wesentlich verbessert. Durch die Anordnungen mehrerer Radial­bohrungen entlang der den Förderbeginn bestimmenden Steuer­kante wird sichergestellt, daß in jeder Drehlage des Pumpen­kolbens wenigstens ein entsprechender gedrosselter Brenn­stoffstrahl zur Wegförderung der Dampfblasen in Richtung zum Saugraum austritt, wobei die radiale Richtung der Spülbohrun­gen einen ordnungsgemäßen Abtransport der Dampfblasen bzw. Hohlräume garantiert. Durch die nebeneinanderliegenden Radialbohrungen, welche in jeder Drehlage einen oder mehrere dünne Spülstrahlen in die Saug- und Überströmbohrung abgeben, wird dabei ein Spülvorhang bzw. Spülfächer zum Abtransport der Dampfblasen unter möglichst geringer Verfälschung der Fördermenge aus dem Pumpenraum erzielt.To achieve this object, the invention consists essentially in that the throttled line connection is formed by a plurality of radial bores arranged along the control edge that determines the start of delivery, which are connected to the working space of the pump piston and directly on the outer surface of the pump piston in a suction and Overflow bore overlap area of the same. Because radial bores open directly into the outer surface of the pump piston and not into a recess in the piston wall, the fuel, which is branched off from the working area of the pump piston and is under high pressure, enters the suction and overflow bore in the form of a directed jet and is directed through this jet the removal effect exerted on the vapor bubbles is significantly improved. The arrangement of a plurality of radial bores along the control edge which determines the start of delivery ensures that at least one corresponding throttled fuel jet emerges in each rotational position of the pump piston for conveying away the vapor bubbles in the direction of the suction chamber, the radial direction of the rinsing bores guaranteeing proper removal of the vapor bubbles or cavities . Due to the adjacent radial bores, which have one or more in each rotational position dispensing thin flushing jets into the suction and overflow bore, a flushing curtain or flushing compartments for removing the steam bubbles is achieved with as little distortion of the delivery rate as possible from the pump chamber.

Gemäß einer bevorzugten Ausführungsform der Erfindung ver­laufen die Radialbohrungen ungefähr parallel zu den Erzeugen­den der Saug- und Überströmbohrung, wodurch die Wegförderung des über die gedrosselte Leitungsverbindung austretenden Strahles optimal wird.According to a preferred embodiment of the invention, the radial bores run approximately parallel to the generatrices of the suction and overflow bores, as a result of which the removal of the jet emerging via the throttled line connection is optimal.

Bei Brennstoffeinspritzpumpen, welche mit hohen Drücken, wie beispielsweise 1500 bar oder darüber arbeiten, ist es zweck­mäßig, daß die Pumpenkolbenbüchse zwei diametral gegenüber­liegende Saug- und Überströmbohrungen aufweist, wobei die Steuerkanten des Pumpenkolbens zentralsymmetrisch an beiden Kolbenseiten angeordnet sind, um eine einseitige hohe Be­lastung des Pumpenkolbens, welche zu einem erhöhten Ver­schleiß des Pumpenkolbens und der Pumpenkolbenbüchse führt, zu vermeiden. Bei solchen Pumpenelementen sind gemäß der Erfindung die Mündungen der Radialbohrungen zentral­symmetrisch an beiden Kolbenseiten angeordnet, so daß in beiden Saug- und Überströmbohrungen die Dampfblasen wegge­fördert werden. Bei solchen mit hohen Drücken arbeitenden Pumpenelementen ist die Gefahr der Entstehung von Kavita­tionen und Erosionen besonders groß und es ist daher wesent­lich, daß diese Gefahr im Bereich der beiden Saug- und Überströmbohrungen ausgeschaltet wird.In fuel injection pumps, which operate at high pressures, such as 1500 bar or above, it is expedient that the pump piston liner has two diametrically opposite suction and overflow bores, the control edges of the pump piston being arranged centrally symmetrically on both piston sides in order to avoid a one-sided high load on the To avoid pump pistons, which leads to increased wear of the pump piston and the pump piston sleeve. In such pump elements, the mouths of the radial bores are arranged centrally symmetrically on both sides of the piston, so that the vapor bubbles are carried away in both suction and overflow bores. With such pump elements working at high pressures, the risk of cavitation and erosion is particularly great and it is therefore essential that this danger is eliminated in the area of the two suction and overflow bores.

Gemäß einer vorteilhaften Ausführungsform der Erfindung gehen die Radialbohrungen von einer zentralen, über einen Drossel­querschnitt mit dem Arbeitsraum des Pumpenkolbens in Verbin­dung stehenden Bohrung des Pumpenkolbens aus. Dadurch wird es ermöglicht, die Bohrungen präzise senkrecht zur Achse des Pumpenkolbens anzuordnen. Gemäß der Erfindung sind zweckmäßig die Radialbohrungen in gleichen Abständen voneinander angeordnet. Vorzugsweise liegen hiebei auch die Mündungen der Radialbohrungen in gleichen Abständen von der Steuerkante. In beiden Fällen werden bei allen Verdrehstellungen des Pumpen­kolbens gleiche Verhältnisse geschaffen und dadurch, daß der Drosselquerschnitt in der zentralen Bohrung vorgesehen ist, bleibt die aus dem Arbeitsraum des Pumpenkolbens abgezweigte Brennstoffmenge unabhängig von der Anzahl der mit den Saug- ­und Überströmbohrungen in Verbindung stehenden Radialbohrun­gen stets gleich.According to an advantageous embodiment of the invention, the radial bores start from a central bore of the pump piston which is connected to the working space of the pump piston via a throttle cross section. This makes it possible to arrange the bores precisely perpendicular to the axis of the pump piston. According to the invention, the radial bores are expediently spaced apart from one another arranged. Preferably, the mouths of the radial bores are equally spaced from the control edge. In both cases, the same conditions are created at all rotational positions of the pump piston, and because the throttle cross section is provided in the central bore, the amount of fuel diverted from the working space of the pump piston always remains independent of the number of radial bores connected to the suction and overflow bores equal.

Gemäß der Erfindung ist die Anordnung vorzugsweise so ge­troffen, daß die Mündungen der Radialbohrungen in einem Abstand von der den Förderbeginn bestimmenden Steuerkante liegen, welcher kleiner ist als der halbe Durchmesser der Saug- und Überströmbohrung. Dadurch wird erreicht, daß der durch die Radialbohrungen austretende Kraftstoffstrahl bereits bei Förderbeginn oder kurz nach Förderbeginn in die Saug- und Überströmbohrung eintritt, so daß genügend Zeit verbleibt, um die Gasblasen aus der Saug- und Überströmboh­rung wezufördern. Durch den in die Saug- und Überströmbohrung eintretenden Kraftstoffstrahl wird auch der Druck in der Saug- und Überströmbohrung erhöht. Diese Druckerhöhung ist aber geringer als die bei Förderende durch den Absteuerstrahl auftretende Druckerhöhung. Es werden daher die noch in der Saug- und Überströmbohrung befindlichen Gasblasen zu einem weicheren Implodieren gebracht, wodurch die Kavitations- und Erosionserscheinungen wesentlich verringert werden.According to the invention, the arrangement is preferably such that the mouths of the radial bores are at a distance from the control edge which determines the start of delivery, which is smaller than half the diameter of the suction and overflow bore. It is thereby achieved that the fuel jet emerging through the radial bores already enters the suction and overflow bore at the start of delivery or shortly after the start of delivery, so that there is sufficient time to convey the gas bubbles from the suction and overflow bore. The fuel jet entering the suction and overflow bore also increases the pressure in the suction and overflow bore. However, this pressure increase is less than the pressure increase occurring at the end of the delivery due to the control jet. The gas bubbles still in the suction and overflow bore are therefore brought to a softer imploding, as a result of which the cavitation and erosion phenomena are substantially reduced.

Dadurch, daß die Radialbohrungen knapp unter der den Förder­beginn bestimmenden Steuerkante an der Kolbenmantelfläche münden, wird der Fördereffekt bereits bei Förderbeginn oder knapp nach Förderbeginn erreicht. Gemäß der Erfindung können aber auch entlang der das Förderende bestimmenden Steuerkante und in gleichen Abständen von dieser Radialbohrungen an der Mantelfläche des Pumpenkolbens münden. Dadurch wird auch noch bei Förderende ein Wegfördern der Gasblasen erreicht.The fact that the radial bores open just below the control edge which determines the start of delivery on the piston jacket surface means that the delivery effect is achieved as soon as delivery begins or just after delivery begins. According to the invention, however, radial bores can also open along the control edge which determines the delivery end and at equal distances therefrom on the lateral surface of the pump piston. As a result, the gas bubbles are conveyed away even at the end of delivery.

Gemäß einer bevorzugten Ausführungsform der Erfindung ist die Ausbildung so getroffen, daß die Radialbohrungen nur in jenen Bereichen des Kolbenmantels münden, welche einer Drehstellung des Pumpenkolbens für große Einspritzmengen entsprechen. Dadurch kann gezielt eine Beseitigung der bei großen Ein­spritzmengen vermehrt auftretenden und daher besonders schädlichen Dampfblasen bewirkt werden.According to a preferred embodiment of the invention, the design is such that the radial bores open only in those areas of the piston skirt which correspond to a rotational position of the pump piston for large injection quantities. In this way, it is possible to specifically eliminate the vapor bubbles that occur increasingly with large injection quantities and are therefore particularly harmful.

Die Radialbohrungen werden nur über einen kurzen Zeitraum durch die Saug- und Überströmbohrungen aufgesteuert. Dadurch wird die durch die Radialbohrungen austretende Brennstoff­menge gering gehalten, so daß die Fördercharakteristik nicht wesentlich beeinflußt wird.The radial holes are only opened for a short period of time by the suction and overflow holes. As a result, the amount of fuel emerging through the radial bores is kept low, so that the delivery characteristics are not significantly influenced.

In der Zeichnung ist die Erfindung an Hand eines Ausführungs­beispieles schematisch erläutert.

  • Fig. 1 und 1a zeigen einen Axialschnitt durch Pumpenkolben und Pumpenkolbenbüchse, wobei Fig.1 die Kolbenstellung knapp nach Förderbeginn und Fig.1a die Kolbenstellung bei Förder­ende darstellt;
  • Fig. 2 zeigt eine Abwickelung der Kolbenman­telfläche in größerem Maßstab bei einer Ausführung nach Fig.1;
  • Fig. 3 zeigt eine Variante in Form einer Abwickelung der Kolbenmantelfläche.
In the drawing, the invention is explained schematically using an exemplary embodiment.
  • 1 and 1a show an axial section through the pump piston and pump piston liner, wherein FIG. 1 shows the piston position just after the start of delivery and FIG. 1a shows the piston position at the end of delivery;
  • Fig. 2 shows a development of the piston jacket surface on a larger scale in an embodiment according to Fig.1;
  • Fig. 3 shows a variant in the form of a development of the piston surface.

Der Pumpenkolben 1 ist in der Pumpenkolbenbüchse 2 zu auf- ­und abgehender Bewegung geführt. Der Antrieb ist nicht dargestellt. In der Pumpenkolbenbüchse 2 sind zwei Saug- und Überströmbohrungen 3 einander diametral gegenüberliegend angeordnet. Die Oberkante 4 des Pumpenkolbens 1 steuert durch Überschleifen der Saug- und Überströmbohrungen 3 den Förder­beginn und die schrägen Steuerkanten 5 steuern das Förderende durch Überschleifen der Saug- und Überströmbohrungen 3. Im Pumpenkolben ist eine zentrale Bohrung 6 vorgesehen, von welcher radiale Bohrungen 7 ausgehen, die unmittelbar an der Mantelfläche des Kolbens 1 münden. Die Mündungen 8 dieser radialen Bohrungen werden daher unmittelbar durch die Wandun­gen 9 der Saug- und Überströmbohrungen 3 aufgesteuert. Die zentrale Bohrung 6 steht über einen Drosselquerschnitt 10 mit dem Arbeitsraum 11 des Pumpenkolbens 1 in Verbindung, so daß diese Drossel 10 auf alle Radialbohrungen 7 wirkt.The pump piston 1 is guided in the pump piston sleeve 2 to move up and down. The drive is not shown. In the pump piston liner 2, two suction and overflow bores 3 are arranged diametrically opposite one another. The upper edge 4 of the pump piston 1 controls the start of delivery by grinding the suction and overflow holes 3 and the oblique control edges 5 control the end of delivery by grinding the suction and overflow holes 3. A central hole 6 is provided in the pump piston, from which radial holes 7 extend. which open directly on the outer surface of the piston 1. The mouths 8 of these radial bores are therefore opened directly through the walls 9 of the suction and overflow bores 3. The central bore 6 is connected via a throttle cross section 10 to the working space 11 of the pump piston 1, so that this throttle 10 acts on all radial bores 7.

Aus den Radialbohrungen 7 tritt bereits bei Förderbeginn oder knapp nach diesem ein gerichteter Brennstoffstrahl aus, der durch den Pfeil 12 angedeutet ist. Dieser gerichtete Brenn­stoffstrahl fördert die Gasblasen 13 in Richtung zum Ansaug­raum aus den Saug- und Überströmbohrungen 3 weg. Mit einem Pfeil 14 ist die Richtung des bei Förderende austretenden Brennstoffstrahles angedeutet (Fig.1a). Dieser bei Förderende austretende scharfe Brennstoffstrahl wird durch die durch die Radialbohrungen 7 austretenden Brennstoffstrahlen gestört und von den Wandungen 9 der Saug- und Überströmbohrungen abge­lenkt. Der Abstand 15 der voneinander in gleichem Abstand liegenden Mündungen 8 der Radialbohrungen 7 von der Kolben­stirnfläche 4 ist sehr klein bemessen und die Mündungen 8 der Bohrungen 7 sind durchwegs in gleichem Abstand 15 von der Kolbenstirnfläche 4, welche den Förderbeginn steuert, ange­ordnet.A directed fuel jet, which is indicated by the arrow 12, emerges from the radial bores 7 already at the start of delivery or just after this. This directed fuel jet conveys the gas bubbles 13 away from the suction and overflow bores 3 in the direction of the suction chamber. An arrow 14 indicates the direction of the fuel jet emerging at the end of delivery (FIG. 1a). This sharp fuel jet emerging at the end of delivery is disturbed by the fuel jets emerging through the radial bores 7 and deflected by the walls 9 of the suction and overflow bores. The distance 15 between the orifices 8 of the radial bores 7, which are at the same distance from one another, is very small and the orifices 8 of the bores 7 are arranged at the same distance 15 from the piston face 4, which controls the start of delivery.

Bei der Anordnung nach Fig.3 sind auch entlang der das Förderende bestimmenden schrägen Steuerkante 5 Bohrungen 16 angeordnet, welche durchwegs in gleichem Abstand 17 von dieser Steuerkante 5 liegen.In the arrangement according to FIG. 3, bores 16 are also arranged along the inclined control edge 5 that determines the end of the conveyor, which bores are all at the same distance 17 from this control edge 5.

Claims (9)

1. Pumpenelement einer Brennstoffeinspritzpumpe für Ein­spritzbrennkraftmaschinen, bei welchem die Pumpenkolben­büchse (2) wenigstens eine Saug- und Überströmbohrung (3) aufweist, die durch Steuerkanten (4,5) des Pumpenkolbens (1) überschliffen wird, wobei wenigstens eine im Bereich der Kolbenstirnfläche angeordnete Steuerkante (4) den Förder­beginn und wenigstens eine am Kolbenmantel angeordnete, insbesondere schräge, Steuerkante (5) das Förderende bestimmt und wobei während wenigstens eines Teiles des Druckhubes des Pumpenkolbens (1) eine gedrosselte Leitungsverbindung zwischen dem Arbeitsraum (11) des Pumpenkolbens (1) und der Saug- und Überströmbohrung (3) besteht, dadurch gekennzeich­net, daß die gedrosselte Leitungsverbindung von mehreren entlang der den Förderbeginn bestimmenden Steuerkante (4) angeordneten Radialbohrungen (7) gebildet ist, welche mit dem Arbeitsraum (11) des Pumpenkolbens (1) in Verbindung stehen und unmittelbar an der Mantelfläche des Pumpenkolbens in einem die Saug- und Überströmbohrung (3) überschleifenden Bereich derselben münden.1. Pump element of a fuel injection pump for injection internal combustion engines, in which the pump piston liner (2) has at least one suction and overflow bore (3) which is ground through control edges (4, 5) of the pump piston (1), at least one arranged in the region of the piston face Control edge (4) determines the start of delivery and at least one, in particular inclined, control edge (5) arranged on the piston skirt determines the end of delivery and wherein a throttled line connection between the working space (11) of the pump piston (1) during at least part of the pressure stroke of the pump piston (1) and the suction and overflow bore (3), characterized in that the throttled line connection is formed by a plurality of radial bores (7) arranged along the control edge (4) which determines the start of delivery, which are connected to the working space (11) of the pump piston (1) in Connect and directly on the outer surface of the pump piston in a di e The suction and overflow bore (3) overlapping area of the same open. 2. Pumpenelement nach Anspruch 1, dadurch gekennzeichnet, daß die Radialbohrungen (7) ungefähr parallel zu den Erzeugenden der Saug- und Überströmbohrung (3) verlaufen.2. Pump element according to claim 1, characterized in that the radial bores (7) run approximately parallel to the generatrix of the suction and overflow bore (3). 3. Pumpenelement nach Anspruch 1 oder 2, dadurch gekenn­zeichnet, daß die Radialbohrungen (7) von einer zentralen, über einen Drosselquerschnitt (10) mit dem Arbeitsraum des Pumpenkolbens in Verbindung stehenden Bohrung des Pumpen­kolbens (1) ausgehen.3. Pump element according to claim 1 or 2, characterized in that the radial bores (7) from a central, via a throttle cross-section (10) with the working space of the pump piston communicating bore of the pump piston (1). 4. Pumpenelement nach Anspruch 1, 2 oder 3, dadurch gekenn­zeichnet, daß die Radialbohrungen (7) in gleichen Abständen voneinander angeordnet sind.4. Pump element according to claim 1, 2 or 3, characterized in that the radial bores (7) are arranged at equal distances from one another. 5. Pumpenelement nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß die Mündungen (8) der Radialbohrungen (7) in gleichen Abständen von der Steuerkante (4) liegen.5. Pump element according to one of claims 1 to 4, characterized in that the mouths (8) of the radial bores (7) lie at equal distances from the control edge (4). 6. Pumpenelement nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß die Mündungen (8) der Radialbohrungen (7) in einem Abstand von der den Förderbeginn bestimmenden Steuerkante (4) liegen, welcher kleiner ist als der halbe Durchmesser der Saug- und Überströmbohrung (3).6. Pump element according to one of claims 1 to 5, characterized in that the mouths (8) of the radial bores (7) are at a distance from the control edge (4) determining the start of delivery, which is smaller than half the diameter of the suction and Overflow hole (3). 7. Pumpenelement nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß auch entlang der das Förderende be­stimmenden Steuerkante (5) und in gleichen Abständen von dieser Radialbohrungen (7) an der Mantelfläche des Pumpen­kolbens (1) münden.7. Pump element according to one of claims 1 to 6, characterized in that also along the control edge determining the conveying end (5) and at equal intervals from this radial bores (7) on the outer surface of the pump piston (1) open. 8. Pumpenelement nach einem der Ansprüche 1 bis 7, dadurch gekennzeichnet, daß die Radialbohrungen (7) nur in jenen Bereichen des Kolbenmantels münden, welche einer Drehstellung des Pumpenkolbens (1) für große Einspritzmengen entsprechen.8. Pump element according to one of claims 1 to 7, characterized in that the radial bores (7) open only in those regions of the piston skirt which correspond to a rotational position of the pump piston (1) for large injection quantities. 9. Pumpenelement nach einem der Ansprüche 1 bis 8, bei welchem die Pumpenkolbenbüchse (2) zwei diametral gegenüber­liegende Saug- und Überströmbohrungen (3) aufweist, wobei die Steuerkanten (4,5) des Pumpenkolbens (1) zentralsymmetrisch an beiden Kolbenseiten angeordnet sind, dadurch gekennzeich­net, daß die Mündungen (8) der Radialbohrungen (7) zentral­symmetrisch an beiden Kolbenseiten angeordnet sind.9. Pump element according to one of claims 1 to 8, in which the pump piston bushing (2) has two diametrically opposite suction and overflow bores (3), the control edges (4, 5) of the pump piston (1) being arranged centrally symmetrically on both piston sides, characterized in that the orifices (8) of the radial bores (7) are arranged centrally symmetrically on both sides of the piston.
EP87890264A 1986-11-21 1987-11-20 Pump element of a fuel injection pump for an injection combustion engine Expired - Lifetime EP0270519B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT3119/86 1986-11-21
AT311986 1986-11-21

Publications (2)

Publication Number Publication Date
EP0270519A1 true EP0270519A1 (en) 1988-06-08
EP0270519B1 EP0270519B1 (en) 1990-07-18

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Application Number Title Priority Date Filing Date
EP87890264A Expired - Lifetime EP0270519B1 (en) 1986-11-21 1987-11-20 Pump element of a fuel injection pump for an injection combustion engine

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EP (1) EP0270519B1 (en)
AT (1) ATE54723T1 (en)
DE (1) DE3763811D1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0444256A1 (en) * 1990-03-01 1991-09-04 Robert Bosch Gmbh Fuel injection device for injection-type internal combustion engines
DE4006899A1 (en) * 1990-03-06 1991-09-12 Mak Maschinenbau Krupp Piston for fuel injection pump - has increased radial clearance over end region to eliminate cavitation
EP0971123A3 (en) * 1998-07-10 2001-04-18 L'orange Gmbh Fuel injection pump

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR788642A (en) * 1935-04-11 1935-10-14 Fuel injection pumps
FR887767A (en) * 1940-06-10 1943-11-23 Saurer Ag Adolph Injection pump with no-load running adjustment
US2513883A (en) * 1947-01-15 1950-07-04 Ingersoll Rand Co Fuel pump for engines
DE1954123A1 (en) * 1968-11-04 1970-05-27 Nippon Denso Co Fuel injection pump for diesel engines
DE2932503A1 (en) * 1979-08-10 1981-02-26 Daimler Benz Ag Diesel engine fuel injection pump - has outlet throttled during part of stroke but throttle closed during cold-start by rotation of piston
GB2152155A (en) * 1983-12-29 1985-07-31 Bosch Gmbh Robert Fuel injection pump for an internal combustion engine

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR788642A (en) * 1935-04-11 1935-10-14 Fuel injection pumps
FR887767A (en) * 1940-06-10 1943-11-23 Saurer Ag Adolph Injection pump with no-load running adjustment
US2513883A (en) * 1947-01-15 1950-07-04 Ingersoll Rand Co Fuel pump for engines
DE1954123A1 (en) * 1968-11-04 1970-05-27 Nippon Denso Co Fuel injection pump for diesel engines
DE2932503A1 (en) * 1979-08-10 1981-02-26 Daimler Benz Ag Diesel engine fuel injection pump - has outlet throttled during part of stroke but throttle closed during cold-start by rotation of piston
GB2152155A (en) * 1983-12-29 1985-07-31 Bosch Gmbh Robert Fuel injection pump for an internal combustion engine

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0444256A1 (en) * 1990-03-01 1991-09-04 Robert Bosch Gmbh Fuel injection device for injection-type internal combustion engines
DE4006899A1 (en) * 1990-03-06 1991-09-12 Mak Maschinenbau Krupp Piston for fuel injection pump - has increased radial clearance over end region to eliminate cavitation
EP0971123A3 (en) * 1998-07-10 2001-04-18 L'orange Gmbh Fuel injection pump

Also Published As

Publication number Publication date
EP0270519B1 (en) 1990-07-18
ATE54723T1 (en) 1990-08-15
DE3763811D1 (en) 1990-08-23

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