EP0422130B1 - Fuel injection pump for internal combustion engines - Google Patents

Fuel injection pump for internal combustion engines Download PDF

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Publication number
EP0422130B1
EP0422130B1 EP89909154A EP89909154A EP0422130B1 EP 0422130 B1 EP0422130 B1 EP 0422130B1 EP 89909154 A EP89909154 A EP 89909154A EP 89909154 A EP89909154 A EP 89909154A EP 0422130 B1 EP0422130 B1 EP 0422130B1
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EP
European Patent Office
Prior art keywords
damping
pump
fuel injection
pump piston
injection pump
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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EP89909154A
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German (de)
French (fr)
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EP0422130A1 (en
Inventor
Roland Kupzik
Eberhard Schunck
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Robert Bosch GmbH
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Robert Bosch GmbH
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Publication of EP0422130A1 publication Critical patent/EP0422130A1/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
    • F02M41/00—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor
    • F02M41/08—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined
    • F02M41/10—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor
    • F02M41/12—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor the pistons rotating to act as the distributor
    • F02M41/121—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor the pistons rotating to act as the distributor with piston arranged axially to driving shaft
    • 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
    • F02M41/00—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor
    • F02M41/08—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined
    • F02M41/10—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor
    • F02M41/12—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor and pumping elements being combined pump pistons acting as the distributor the pistons rotating to act as the distributor
    • 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

Definitions

  • the invention relates to a fuel injection pump according to the preamble of the main claim. It is already known from DE-OS 31 44 277 a fuel injection pump, which has a hydraulic interception device to increase performance by increasing the conveying speed of the pump piston in order to retard the oscillating pump piston, from the coil springs that hold the pump piston in contact with the Forehead cams should hold, supplementary restoring forces that can no longer be realized.
  • the known hydraulic interception device requires a throttle groove on the pump piston in order to limit the outflow of the fuel from a damping chamber. Attaching the throttle groove to the pump piston requires additional and also cost-intensive work processes, since the throttle groove on the pump piston usually has to be created by eroding. Furthermore, the braking effect of this interception device acts on the major part of the pump piston movement, so that higher driving forces than necessary are necessary.
  • EP-AO 182 159 discloses a fuel injection pump with a hydraulic interception device for the pump piston.
  • a control piston On a part of the stepped pump piston, a control piston is fixed in a longitudinally displaceable manner and, during the delivery stroke of the pump piston, against which the stepped annular shoulder rests and forms the throttling annular gap to the suction chamber of the fuel injection pump when immersed in the damping chamber opposite the cylinder liner and thereby brakes the pump piston.
  • the object of the invention is to further develop the generic fuel injection pump so that, in the case of simply designed pump pistons, braking of the pump piston only occurs in the event of an actual lifting of the pump piston taking place at high operating speeds or the cam disk driving this from the roller ring.
  • FIG. 1 shows a simplified side view of a fuel injection pump, partially in section
  • FIG. 2 shows a schematic illustration of a partial section through a cylinder liner of the fuel injection pump with the pump piston guided in the cylinder liner.
  • FIG. 1 a partial section through a fuel injection pump of the valve type is shown in a simplified representation in FIG. 1, in which a drive shaft 2 is mounted in a housing 1 and to which a lifting disk 3 arranged transversely to the drive shaft 2 is coupled, which corresponds to the number to be supplied Cylinder the internal combustion engine is provided with front cams 4.
  • a pump piston 9 sliding in a bore 7 of a cylinder liner 8 has a collar 10 on its drive-side end which projects into a fuel-filled suction chamber 26 and is connected to the lifting disk 3 in a rotationally fixed manner.
  • a control slide 11 which surrounds the pump piston 9, slides on the drive-side pump piston section, in which a transverse bore 12 controlled by the control slide 11 is arranged for the control of partial quantities of the fuel delivered, which is connected to a longitudinal bore 13 leading to the front side of the pump piston 9 and there opens into a pump work room 14.
  • Adjustment means 15 act on the control slide 11, the position of which is controlled in a known manner by a speed controller.
  • a slide rail 16 against which a yoke 18 loaded by at least one return spring 17 presses.
  • a return spring 17 Extending coaxially with the return spring 17 is a guide pin 19 which is fastened on the one hand in size 1 and on the other hand reaches through a fit 20 in the yoke 18 so that the yoke 18 is secured against rotation.
  • the return spring 17 is supported at one end by a spring plate 21 on the housing 1 and at the other end on the yoke 18, whereby the lifting disk 3 is pressed against the rollers 5.
  • FIG. 2 shows a partial view of a fuel injection pump according to FIG. 1 modified according to the invention.
  • the pump piston 9 is of stepped design, wherein the smaller diameter part of the pump piston 9 is slidably guided in the bore 7 of the cylinder liner 8.
  • the cylinder liner 8 has a damping bore 24, which is designed as a damping chamber and extends from the suction chamber and faces the larger diameter part of the pump piston 9 and whose axis coincides with the axis of the pump piston 9.
  • the end-face annular surface between the large diameter and the small diameter of the pump piston 9 forms a damping surface 23.
  • the pump piston 9 assumes a lowermost movement position UT and an uppermost movement position OT within one movement cycle.
  • the pump piston 9 in contact with the end cam 4 with the damping surface 23 in TDC approaches the front boundary of the damping chamber 22 to a small extent, which is less than 1 mm, exceeds the inertial force of the pump piston 9 at high speed the contact pressure of the return spring 17, the positive connection between the pump piston 9 and front cam 4 is lost.
  • the damping surface 23 of the pump piston 9 can thus enter the damping space 23, as a result of which it forms an annular gap 25 between the outer surface of the larger diameter part of the pump piston 9 and the damping bore 24 delimiting the damping space, which gap then forms the only connection between the two Damping chamber 22 to a suction chamber 26 of the fuel injection pump leading as a relief chamber.
  • the throttled evasive capacity of the fuel enclosed in the damping chamber 22 creates a hydraulic spring, the restoring force of which counteracts the movement of the pump piston 9 and supports the actuating force of the return spring 17 in the same direction after the delivery stroke movement of the pump piston 9.
  • other or additional throttle connections from the damping space 22 to the suction space 26 or other storage spaces can also be provided in order to reduce the maximum pressure.
  • the functional sequence described results in the following sequence of effects.
  • the front cam 4 has its smallest outer contour in TDC Radius on with the result that the form-fitting following pump piston 9 experiences the greatest delays here.
  • a strongly accelerated pump piston 9 lifts off the front cam 4 before TDC, but is quickly limited and quickly returned to the front cam 4 by the damped braking shortly after TDC, which increases the functionality of the cam drive.
  • the transverse forces caused by the delivery stroke pressure as a result of the torsion of the drive shaft 2 and the displacements of the cam drive can cause wear points which lead to the pump piston 9 jamming.
  • the previously described positive locking separation between pump piston 9 and end cam 4 avoids the influence of transverse forces on the pump piston before TDC; this largely avoids the bearing wear of the pump piston 9.
  • the exemplary embodiment described thus allows, by intercepting the oscillating pump piston 9 by means of the additional hydraulic force in the manner according to the invention, with lower susceptibility to wear, higher delivery speeds or drive speeds of the fuel injection pump or higher stroke rates of the pump piston per revolution with the same delivery rate, which results in an increase in performance of the fuel injection pump.

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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

A device for retarding the pump piston (9) of a fuel injection pump for internal combustion engines comprises a pump piston (9) slidingly and rotatably mounted in a bore (7). The pump piston (9) is of stepped design and, if it is subjected to high accelerations and the positive engagement with the cam drive fails, the section of widest diameter can penetrate into a stationary damping chamber (22), to form an annular gap (25), shortly after reaching the end of its upward stroke. This restricts the escape of the fuel inside the damping chamber (22), thereby creating a hydraulic spring whose restoring force acts counter to the direction of motion of the pump piston (9). The pump piston (9) is therefore intercepted even at high delivery rates, which enhances the efficiency of the fuel injection pump.

Description

Stand der TechnikState of the art

Die Erfindung geht aus von einer Kraftstoffeinspritzpumpe nach der Gattung des Hauptanspruchs. Es ist schon durch die DE-OS 31 44 277 eine Kraftstoffeinspritzpumpe bekannt, die zur Leistungssteigerung über die Erhöhung der Fördergeschwindigkeit des Pumpenkolbens eine hydraulische Abfangvorrichtung aufweist, um die zur Verzögerung des oszillierenden Pumpenkolbens erforderlichen, von den Schraubenfedern, die den Pumpenkolben in Anlage mit dem Stirnnocken halten sollen, nicht mehr realisierbaren Rückstellkräfte zu ergänzen. Die bekannte hydraulische Abfangvorrichtung benötigt eine Drosselnut am Pumpenkolben, um die Abströmung des Kraftstoffes aus einem Dämpfungsraum zu begrenzen. Das Anbringen der Drosselnut am Pumpenkolben erfordert zusätzliche und zudem kostenintensive Arbeitsvorgänge, da die Drosselnut am Pumpenkolben üblicherweise durch Ero- dieren erstellt werden muß. Des weiteren beaufschlagt die Bremswirkung dieser Abfangvorrichtung den überwiegenden Teil der Pumpenkolbenbewegung, so daß höhere Antriebskräfte als erforderlich notwendig werden.The invention relates to a fuel injection pump according to the preamble of the main claim. It is already known from DE-OS 31 44 277 a fuel injection pump, which has a hydraulic interception device to increase performance by increasing the conveying speed of the pump piston in order to retard the oscillating pump piston, from the coil springs that hold the pump piston in contact with the Forehead cams should hold, supplementary restoring forces that can no longer be realized. The known hydraulic interception device requires a throttle groove on the pump piston in order to limit the outflow of the fuel from a damping chamber. Attaching the throttle groove to the pump piston requires additional and also cost-intensive work processes, since the throttle groove on the pump piston usually has to be created by eroding. Furthermore, the braking effect of this interception device acts on the major part of the pump piston movement, so that higher driving forces than necessary are necessary.

Des weiteren ist auch durch die EP-A-O 182 159 eine Kraftstoffeinspritzpumpe mit einer hydraulischen Abfangvorrichtung für den Pumpenkolben bekannt. Auf einem Teil des gestuften Pumpenkolben ist ein Steuerkolben längsverschiebbar festgelegt, der beim Förderhub des Pumpenkolbens, an dessen die Stufung bildenden Ringschulter anliegt und beim Eintauchen in den Dämpfungsraum gegenüber der Zylinderbüchse den drosselnden Ringspalt zum Saugraum der Kraftstoffeinspritzpumpe bildet und dadurch den Pumpenkolben abbremst.Furthermore, EP-AO 182 159 discloses a fuel injection pump with a hydraulic interception device for the pump piston. On a part of the stepped pump piston, a control piston is fixed in a longitudinally displaceable manner and, during the delivery stroke of the pump piston, against which the stepped annular shoulder rests and forms the throttling annular gap to the suction chamber of the fuel injection pump when immersed in the damping chamber opposite the cylinder liner and thereby brakes the pump piston.

Beim anschließenden Saughub kehrt sich die Axialbewegung des Pumpenkolbens um, wodurch sich der Steuerkolben unter Bildung eines der Füllung des Dämpfungsraumes dienenden Spaltes von der Ringschulter löst, bis er zur Anlage an eine am Pumpenkolben fixierte Ringfeder kommt.During the subsequent suction stroke, the axial movement of the pump piston is reversed, as a result of which the control piston separates from the annular shoulder, forming a gap which serves to fill the damping space, until it comes to rest against an annular spring fixed to the pump piston.

Diese Anordnung ist durch die auf dem Pumpenkolben angebrachten Zusatzteile aufwendig, wodurch ein zusätzliches Fehlerpotential gebildet ist.This arrangement is complex due to the additional parts attached to the pump piston, as a result of which an additional error potential is formed.

Aufgabe der Erfindung ist, die gattungsgemäße Kraftstoffeinspritzpumpe so weiterzubilden, daß bei einfach gestalteten Pumpenkolben ein Abbremsen des Pumpenkolbens erst im Falle eines tatsächlichen, bei hohen Betriebsdrehzahlen erfolgenden Abhebens des Pumpenkolbens oder die diesen antreibenden Nockenscheibe vom Rollenring auftritt.The object of the invention is to further develop the generic fuel injection pump so that, in the case of simply designed pump pistons, braking of the pump piston only occurs in the event of an actual lifting of the pump piston taking place at high operating speeds or the cam disk driving this from the roller ring.

Diese Aufgabe wird erfindungsgemäß durch die kennzeichnenden Merkmale des Patentanspruchs 1 gelöst.This object is achieved by the characterizing features of claim 1.

Damit ist eine weitere Erhöhung der Geschwindigkeit des Pumpenkolbens und damit eine Leistungssteigerung der Kraftstoffeinspritzpumpe möglich, obwohl der hydraulische Anschlag keine zusätzliche Entlastungsnut aufweist und die Bremswirkung nur partiell im Bereich des oberen Umkehrpunktes des Pumpenkolbens erfolgt. Besonders vorteilhaft ist dabei, daß der Förderhubdruck und der Bremsdruck auf dem Pumpenkolben zeitlich hintereinander ablaufen und so Querkräfte, die das Blockieren des Pumpenkolbens hervorrufen können, vermieden werden. Durch die in den Unteransprüchen aufgeführten Maßnahmen sind vorteilhafte Weiterbildungen und Verbesserungen der im Hauptanspruch angegebenen hydraulischen Abfangvorrichtung möglich.A further increase in the speed of the pump piston and thus an increase in performance of the fuel injection pump is possible, although the hydraulic stop has no additional relief groove and the braking effect is only partially in the area of the upper turning point of the pump piston. It is particularly advantageous that the delivery stroke pressure and the brake pressure on the pump piston run in succession, thus avoiding transverse forces that can cause the pump piston to lock. The measures listed in the subclaims allow advantageous developments and improvements of the hydraulic interception device specified in the main claim.

Zeichnungdrawing

Die Erfindung ist in der Zeichnung anhand zweier Figuren dargestellt und in der nachfolgenden Beschreibung nähen erläutert. Es zeigt Figur 1 eine vereinfachte Seitenansicht einen Kraftstoffeinspritzpumpe, teilweise geschnitten und Figur 2 in schematischen Darstellung einen Teilschnitt durch eine Zylinderbüchse der Kraftstoffeinspritzpumpe mit dem in den Zylinderbüchse geführten Pumpenkolben.The invention is illustrated in the drawing with reference to two figures and sewing explained in the following description. FIG. 1 shows a simplified side view of a fuel injection pump, partially in section, and FIG. 2 shows a schematic illustration of a partial section through a cylinder liner of the fuel injection pump with the pump piston guided in the cylinder liner.

Beschreibung den AusführungsbeispieleDescription of the embodiments

In den Zeichnung ist in Figur 1 in vereinfachten Darstellung ein Teilschnitt durch eine Kraftstoffeinspritzpumpe den Venteilerbauart dangestellt, bei den in einem Gehäuse 1 eine Antriebswelle 2 gelagert und an welche eine quer zur Antriebswelle 2 angeordnete Hubscheibe 3 gekoppelt ist, die entsprechend den zu versorgenden Zahl den Zylinder den Brennkraftmaschine mit Stirnnocken 4 versehen ist.In the drawing, a partial section through a fuel injection pump of the valve type is shown in a simplified representation in FIG. 1, in which a drive shaft 2 is mounted in a housing 1 and to which a lifting disk 3 arranged transversely to the drive shaft 2 is coupled, which corresponds to the number to be supplied Cylinder the internal combustion engine is provided with front cams 4.

Die Lauffläche der Hubscheibe 3 liegt auf Rollen 5 auf, die in einem feststehenden Rollenring 6 gehalten sind. Ein in einer Bohrung 7 einer Zylinderbüchse 8 gleitender Pumpenkolben 9 hat an seinem antriebsseitigen, in einen kraftstoffgefüllten Saugraum 26 ragenden Ende einen Bund 10, der mit der Hubscheibe 3 drehfest verbunden ist. Zur Steuerung der Kraftstoffeinspritzmenge gleitet ein dem Pumpenkolben 9 umgreifender Steuerschieber 11 auf dem antriebsseitigen Pumpenkolbenabschnitt, in dem zum Absteuern von Teilmengen des geförderten Kraftstoffs eine vom Steuerschieber 11 gesteuerte Querbohrung 12 angeordnet ist, die mit einer zur Stirnseite des Pumpenkolbens 9 führenden Längsbohrung 13 verbunden ist und dort in einen Pumpenarbeitsraum 14 mündet. An dem Steuerschieber 11 greifen Verstellmittel 15 an, deren Stellung in bekannter Weise von einem Drehzahlregler gesteuert wird. An dem Bund 10 des Pumpenkolbens 9 liegt eine Gleitschiene 16 an, gegen die ein von wenigstens einer Rückholfeder 17 belastetes Joch 18 drückt. Vereinfachend ist nur eine Rückholfeder 17 dargestellt, vorzugsweise sind jedoch zwei oder mehrere Rückholfedern 17 vorgesehen. Gleichachsig zur Rückholfeder 17 erstreckt sich ein Führungsstift 19, der einerseits in Größe 1 befestigt und andererseits durch eine Paßform 20 im Joch 18 hindurchgreift, so daß das Joch 18 gegen Verdrehen gesichert ist. Die Rückholfeder 17 stützt sich mit ihrem einen Ende über einen Federteller 21 am Gehäuse 1 und mit dem anderen Ende am Joch 18 ab, wodurch die Hubscheibe 3 gegen die Rollen 5 gedrückt wird. Beim Drehen der Antriebswelle 2 wird der Pumpenkolben 9 in gleicher Weise mitgedreht und zusätzlich hin und her bewegt, wobei der Förderhub durch die Stirnnocken 4 der Hubscheibe 13 entgegen der Wirkung der Rückholfeder 17 und der Saughub durch die gespeicherte Kraft der Rückholfeder 17 bewirkt wird.The running surface of the lifting disk 3 rests on rollers 5 which are held in a fixed roller ring 6. A pump piston 9 sliding in a bore 7 of a cylinder liner 8 has a collar 10 on its drive-side end which projects into a fuel-filled suction chamber 26 and is connected to the lifting disk 3 in a rotationally fixed manner. In order to control the fuel injection quantity, a control slide 11, which surrounds the pump piston 9, slides on the drive-side pump piston section, in which a transverse bore 12 controlled by the control slide 11 is arranged for the control of partial quantities of the fuel delivered, which is connected to a longitudinal bore 13 leading to the front side of the pump piston 9 and there opens into a pump work room 14. Adjustment means 15 act on the control slide 11, the position of which is controlled in a known manner by a speed controller. On the collar 10 of the pump piston 9 is a slide rail 16 against which a yoke 18 loaded by at least one return spring 17 presses. To simplify matters, only one return spring 17 is shown, but preferably two or more return springs 17 are provided. Extending coaxially with the return spring 17 is a guide pin 19 which is fastened on the one hand in size 1 and on the other hand reaches through a fit 20 in the yoke 18 so that the yoke 18 is secured against rotation. The return spring 17 is supported at one end by a spring plate 21 on the housing 1 and at the other end on the yoke 18, whereby the lifting disk 3 is pressed against the rollers 5. When the drive shaft 2 is rotated, the pump piston 9 is rotated in the same way and additionally moved back and forth, the delivery stroke being effected by the end cams 4 of the lifting disk 13 counter to the action of the return spring 17 and the suction stroke by the stored force of the return spring 17.

Das in Figur 2 dargestellte Ausführungsbeispiel zeigt eine Teilansicht einer erfindungsgemäß modifizierten Kraftstoffeinspritzpumpe nach Figur 1. Dabei ist der Pumpenkolben 9 gestuft ausgeführt, wobei der im Durchmesser kleinere Teil des Pumpenkolbens 9 in der Bohrung 7 der Zylinderbüchse 8 gleitend geführt ist. Die Zylinderbüchse 8 weist eine als Dämpfungsraum ausgebildete, vom Saugraum ausgehende Dämpfungsbohrung 24 auf, die dem im Durchmesser größeren Teil des Pumpenkolbens 9 zugewandt ist und deren Achse mit der Achse des Pumpenkolbens 9 zusammenfällt. Die stirnseitige Ringfläche zwischen dem großen Durchmesser und dem kleinen Durchmesser des Pumpenkolbens 9 bildet eine Dämpfungsfläche 23. Der Pumpenkolben 9 nimmt innerhalb einem Bewegungszyklus eine unterste Bewegungslage UT und eine oberste Bewegungslage OT ein. Bei einer Förderhubbewegung nähert sich der in Anlage mit dem Stirnnocken 4 befindliche Pumpenkolben 9 mit der Dämpfungsfläche 23 in OT bis auf ein geringes Maß, das geringer als 1 mm ist, der vorderen Begrenzung des Dämpfungsraums 22. Übersteigt bei hoher Geschwindigkeit die Massenkraft des Pumpenkolbens 9 die Anpreßkraft der Rückholfeder 17, so geht der Formschluß zwischen Pumpenkolben 9 und Stirnnocken 4 verloren. Kurz nach OT kann dadurch die Dämpfungsfläche 23 des Pumpenkolbens 9 in den Dämpfungsraum 23 eintreten, wodurch sie zwischen der Mantelfläche des im Durchmesser größeren Teils des Pumpenkolbens 9 und er dem Dämpfungsraum begrenzenden Dämpfungsbohrung 24 ein ringförmiger Spalt 25 bildet, der dann die einzige Verbindung von dem Dämpfungsraum 22 zu einem als Entlastungsraum führenden Saugraum 26 der Kraftstoffeinspritzpumpe darstellt. Durch das gedrosselte Ausweichvermögen des im Dämpfungsraum 22 eingeschlossenen Kraftstoffs entsteht eine hydraulische Feder, deren Rückstellkraft der Bewegung des Pumpenkolbens 9 entgegengerichtet ist und nach der Förderhubbewegung des Pumpenkolbens 9 die Stellkraft der Rückholfeder 17 gleichgerichtet unterstützt. Zur Modifikation der Rückführkraft bzw. Dämpfung können auch andere oder zusätzliche Drosselverbindungen des Dämpfungsraumes 22 zum Saugraum 26 oder anderen Speicherräumen vorgesehen werden, um den Maximaldruck zu reduzieren.The exemplary embodiment shown in FIG. 2 shows a partial view of a fuel injection pump according to FIG. 1 modified according to the invention. The pump piston 9 is of stepped design, wherein the smaller diameter part of the pump piston 9 is slidably guided in the bore 7 of the cylinder liner 8. The cylinder liner 8 has a damping bore 24, which is designed as a damping chamber and extends from the suction chamber and faces the larger diameter part of the pump piston 9 and whose axis coincides with the axis of the pump piston 9. The end-face annular surface between the large diameter and the small diameter of the pump piston 9 forms a damping surface 23. The pump piston 9 assumes a lowermost movement position UT and an uppermost movement position OT within one movement cycle. During a conveying stroke movement, the pump piston 9 in contact with the end cam 4 with the damping surface 23 in TDC approaches the front boundary of the damping chamber 22 to a small extent, which is less than 1 mm, exceeds the inertial force of the pump piston 9 at high speed the contact pressure of the return spring 17, the positive connection between the pump piston 9 and front cam 4 is lost. Shortly after TDC, the damping surface 23 of the pump piston 9 can thus enter the damping space 23, as a result of which it forms an annular gap 25 between the outer surface of the larger diameter part of the pump piston 9 and the damping bore 24 delimiting the damping space, which gap then forms the only connection between the two Damping chamber 22 to a suction chamber 26 of the fuel injection pump leading as a relief chamber. The throttled evasive capacity of the fuel enclosed in the damping chamber 22 creates a hydraulic spring, the restoring force of which counteracts the movement of the pump piston 9 and supports the actuating force of the return spring 17 in the same direction after the delivery stroke movement of the pump piston 9. To modify the return force or damping, other or additional throttle connections from the damping space 22 to the suction space 26 or other storage spaces can also be provided in order to reduce the maximum pressure.

Der beschriebene Funktionsablauf ergibt den nachfolgenden Wirkungsablauf. Der Stirnnocken 4 weist seiner Außenkontur in OT kleinsten Radius auf mit der Folge, daß der formschlüssig folgende Pumpenkolben 9 hier die größten Verzögerungen erfährt. Bei dem geschilderten Ausführungsbeispiel hebt ein stark beschleunigter Pumpenkolben 9 vor OT von dem Stirnnocken 4 ab, wird jedoch durch die gedämpfte Abbremsung kurz nach OT in seinem Freiflug schnell begrenzt und rasch auf den Stirnnocken 4 zurückgeführt, wodurch die Funktionsfähigkeit des Nockentriebs erhöht wird. Die durch den Förderhubdruck verursachten Querkräfter infolge der Torsion der Antriebswelle 2 und der Verschiebungen des Nockentriebs können Verschleißstellen verursachen, die zum Festlaufen des Pumpenkolbens 9 führen. Die zuvor beschriebene Formschlußtrennung zwischen Pumpenkolben 9 und Stirnnocken 4 vermeidet den Querkrafteinfluß auf den Pumpenkolben vor OT; damit wird der Lagerverschleiß des Pumpenkolbens 9 weitgehend umgangen. Das geschilderte Ausführungsbeispiel erlaubt somit durch das Abfangen des oszillierenden Pumpenkolbens 9 mittels der hydraulischen Zusatzkraft in der erfindungsgemäßen Art bei geringerer Verschleißanfälligkeit höhere Fördergeschwindigkeiten bzw. Antriebsdrehzahlen der Kraftstoffeinspritzpumpe oder höhere Hubzahlen des Pumpenkolbens pro Umdrehung bei gleicher Fördermenge, was eine Leistungssteigerung der Kraftstoffeinspritzpumpe zur Folge hat.The functional sequence described results in the following sequence of effects. The front cam 4 has its smallest outer contour in TDC Radius on with the result that the form-fitting following pump piston 9 experiences the greatest delays here. In the described embodiment, a strongly accelerated pump piston 9 lifts off the front cam 4 before TDC, but is quickly limited and quickly returned to the front cam 4 by the damped braking shortly after TDC, which increases the functionality of the cam drive. The transverse forces caused by the delivery stroke pressure as a result of the torsion of the drive shaft 2 and the displacements of the cam drive can cause wear points which lead to the pump piston 9 jamming. The previously described positive locking separation between pump piston 9 and end cam 4 avoids the influence of transverse forces on the pump piston before TDC; this largely avoids the bearing wear of the pump piston 9. The exemplary embodiment described thus allows, by intercepting the oscillating pump piston 9 by means of the additional hydraulic force in the manner according to the invention, with lower susceptibility to wear, higher delivery speeds or drive speeds of the fuel injection pump or higher stroke rates of the pump piston per revolution with the same delivery rate, which results in an increase in performance of the fuel injection pump.

Claims (4)

1. Fuel injection pump for internal combustion engines having at least one stepped pump plunger (9), which is moved by a cam drive and whose part of smaller diameter alternately executes a suction stroke and a delivery stroke in a bore (7) of a cylinder sleeve (8) of the fuel injection pump for the purpose of supplying fuel to an injection system and at the same time delimits with one end face a pump working space (14), having a damping space (22), which is connected to a suction space (26) of the fuel injection pump and the volume of which can be altered by the pump plunger (9), and having at least one return spring (17) which guides the pump plunger (9) back and can be brought [sic] into contact with the cam drive and is supported against the housing (1), having a damping face (23) which extends on the part of the pump plunger (9) of larger diameter, perpendicularly to the delivery direction of the pump plunger (9), and, at the end of the delivery stroke of the pump plunger (9) can be brought into the damping space (22), forming a throttling gap (25) which then forms a sole connection to the suction space, characterised in that the damping face (23) only reaches the entry cross-section of the damping space (22) shortly after the uppermost cam-drive-guided motional position (TDC) of the pump plunger (9), in which the latter has lifted off from the cam drive.
2. Fuel injection pump according to Claim 1, characterized in that the damping space (22) is delimited radially by a damping bore (24) and the axes of the damping bore (24) and of the bore (7) of the cylinder sleeve (8) are the same.
3. Fuel injection pump according to Claim 1, characterized in that the damping face (23) is formed from an annular front face between the large diameter and the small diameter of the pump plunger (9).
4. Fuel injection pump according to preceding claims, characterized in that the gap (25) is formed by the motional play between the circumferential surface of the larger part of the pump plunger (9) and a damping bore (24) radially delimiting the damping space (22).
EP89909154A 1988-12-22 1989-08-17 Fuel injection pump for internal combustion engines Expired - Lifetime EP0422130B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3843162A DE3843162A1 (en) 1988-12-22 1988-12-22 FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES
DE3843162 1988-12-22

Publications (2)

Publication Number Publication Date
EP0422130A1 EP0422130A1 (en) 1991-04-17
EP0422130B1 true EP0422130B1 (en) 1992-05-13

Family

ID=6369796

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Application Number Title Priority Date Filing Date
EP89909154A Expired - Lifetime EP0422130B1 (en) 1988-12-22 1989-08-17 Fuel injection pump for internal combustion engines

Country Status (7)

Country Link
US (1) US5127381A (en)
EP (1) EP0422130B1 (en)
KR (1) KR960010289B1 (en)
BR (1) BR8907259A (en)
DE (2) DE3843162A1 (en)
ES (1) ES2019764A6 (en)
WO (1) WO1990007055A1 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3943245A1 (en) * 1989-12-29 1991-07-04 Bosch Gmbh Robert FUEL INJECTION PUMP
US6126412A (en) * 1997-12-10 2000-10-03 Caterpillar Inc. Fluid driven piston assembly and fuel injector using same
DE10126686A1 (en) * 2001-06-01 2002-12-19 Bosch Gmbh Robert Fuel injection system, for an IC motor, has a pressure amplifier with a sliding piston and controlled outflow cross section stages to set the fuel pressure according to the piston stroke and give a boot injection action
ITCS20070034A1 (en) * 2007-07-12 2009-01-13 Ungaro S R L HEAT EXCHANGER FOR TERMINAL BOARD
WO2020248275A1 (en) * 2019-06-14 2020-12-17 胡永生 Feeding mechanism of wallboard forming machine for prefabricated integration

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2142704C3 (en) * 1971-08-26 1974-04-25 Robert Bosch Gmbh, 7000 Stuttgart Fuel injection pump for multi-cylinder internal combustion engines
DE2349581C2 (en) * 1973-10-03 1983-10-13 Robert Bosch Gmbh, 7000 Stuttgart Fuel distributor injection pump for internal combustion engines
DE3144277C2 (en) * 1981-11-07 1995-06-01 Bosch Gmbh Robert Fuel injection pump for internal combustion engines
DE3329384A1 (en) * 1983-08-13 1985-02-28 Robert Bosch Gmbh, 7000 Stuttgart Fuel injection pump for internal combustion engines
DE3336869A1 (en) * 1983-10-11 1985-04-25 Robert Bosch Gmbh, 7000 Stuttgart Fuel injection pump for multi-cylinder internal combustion engines
JPS61112771A (en) * 1984-11-06 1986-05-30 Nissan Motor Co Ltd Distributive fuel injection pump
DE3516455A1 (en) * 1985-05-08 1986-11-13 Robert Bosch Gmbh, 7000 Stuttgart FUEL INJECTION PUMP
DE3788406T2 (en) * 1986-09-25 1994-04-14 Ganser Hydromag Zuerich Electronically controlled injection system.
JPH01244144A (en) * 1988-03-25 1989-09-28 Yamaha Motor Co Ltd High pressure fuel injection device for engine

Also Published As

Publication number Publication date
WO1990007055A1 (en) 1990-06-28
KR910700405A (en) 1991-03-15
BR8907259A (en) 1991-03-12
KR960010289B1 (en) 1996-07-27
EP0422130A1 (en) 1991-04-17
DE3843162A1 (en) 1990-06-28
DE58901432D1 (en) 1992-06-17
ES2019764A6 (en) 1991-07-01
US5127381A (en) 1992-07-07

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