EP0318535B1 - Fuel injection pump - Google Patents

Fuel injection pump Download PDF

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Publication number
EP0318535B1
EP0318535B1 EP88904480A EP88904480A EP0318535B1 EP 0318535 B1 EP0318535 B1 EP 0318535B1 EP 88904480 A EP88904480 A EP 88904480A EP 88904480 A EP88904480 A EP 88904480A EP 0318535 B1 EP0318535 B1 EP 0318535B1
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EP
European Patent Office
Prior art keywords
valve
pump
piston
distributor
bore
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP88904480A
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German (de)
French (fr)
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EP0318535A1 (en
Inventor
Gérard Duplat
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Robert Bosch GmbH
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Robert Bosch GmbH
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • 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
    • F02M59/36—Varying fuel delivery in quantity or timing by variably-timed valves controlling fuel passages to pumping elements or overflow passages
    • F02M59/366—Valves being actuated electrically
    • 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
    • F02M41/02—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor being spaced from pumping elements
    • F02M41/06—Fuel-injection apparatus with two or more injectors fed from a common pressure-source sequentially by means of a distributor the distributor being spaced from pumping elements the distributor rotating

Definitions

  • the invention is based on a fuel injection pump of the distributor type for supplying a plurality of injection nozzles of an internal combustion engine, in particular a diesel internal combustion engine, of the type defined in the preamble of claim 1.
  • a rotary valve is mounted, which is driven by a planetary gear during the rotation of the distributor piston and with recesses from in Axial direction of variable width is provided for controlling a relief line of the pump work space.
  • the valve member which is designed as a rotary slide valve, is longitudinally displaced by an electromagnet, in particular for controlling the fuel injection quantity, while it controls the start of injection and also the duration of the injection when it rotates.
  • an electromagnet in particular for controlling the fuel injection quantity, while it controls the start of injection and also the duration of the injection when it rotates.
  • a great deal of design effort and precise synchronization of the rotary drive of the rotary valve is required.
  • With the small size of the rotary valve there is also only a small overlap width, which should ensure the tightness of the valve at closing times. This is problematic due to the necessary play in the longitudinal and circumferential directions of the rotary valve and the high fuel pressure of the fuel to be controlled.
  • the object of the invention is to develop the fuel injection pump mentioned at the outset in such a way that precise and easy-to-implement control of the fuel injection is achieved.
  • the fuel injection pump according to the invention with the characterizing features of claim 1 has the advantage of an extremely reduced dead volume in the pump work space and a small space requirement. Instead of the complete electro valve, only the simple electromagnet is present in the pump housing itself. There are no holes in the pump housing for connecting the switching valve.
  • the fuel injection pump of the distributor type shown in longitudinal section in FIG. 1 is a radial piston pump for supplying a total of four injection nozzles of a diesel engine with predetermined fuel metering under injection pressure.
  • the fuel injection pump has a housing 11 which is closed in a liquid-tight manner by a housing cover 12.
  • a drive shaft 14 is rotatably mounted in the housing 11 by means of a bearing 13.
  • a cover part 15 protruding in a scar-like manner on the housing cover 12 is provided with an axial cylinder bore 16 and a total of four radial bores 17 which are uniformly offset in relation to one another in a cross-sectional plane, of which two radial bores 17 can be seen in FIG. 1.
  • a distributor piston 18 which is rotatably coupled to the drive shaft 14.
  • the coupling takes place via coupling elements 19 which lie in a form-fitting manner in grooves in the drive shaft 14 on the one hand and in the distributor piston 18 on the other hand.
  • the distributor piston 18 is secured in its axial position by a locking ring 20.
  • a pump piston 21 is sealingly guided, which projects out of the radial bore 17 and is connected there to a tappet cup 22.
  • the tappet cup 22 abuts a cam or roller 23 on the cam track 24 of a cam ring 25 connected in a rotationally fixed manner to the drive shaft 14.
  • Tappet cup 22 and roller 23 form a so-called roller tappet, which is displaceable in a guide shaft 26 coaxial with the radial bore 17, so that the assembly of roller 23, tappet cup 22 and pump piston 21 during the rotation of the cam ring 25 to the elevations and depressions of the cam track 24 can follow.
  • a helical compression spring 27, which is supported on the base of the guide shaft 26 and in the interior of the tappet cup 22, ensures the frictional engagement of the tappet cup 22 on the roller 23 and the roller 23 on the cam track 24.
  • Each pump piston 21 delimits on its inside a pump working chamber 28 which is open towards the distributor piston 18 and is delimited there by an annular groove 58 on the distributor piston 18.
  • the distributor piston 18 contains a distributor bore 30, which in the interior of the distributor piston 18 in a valve chamber 31 and on the circumference of the distributor piston 18 in a distributor groove 32 flows.
  • the axial length of the distributor groove 32 is dimensioned such that it extends from the annular groove 58 to the mouths of the injection bores 29, and connects the pump working chamber 28 to an injection bore 29 when the distributor piston 18 is suitably rotated.
  • the distributor piston 18 also contains an axial inlet groove 33, which extends from four radial inlet bores 34 in the cover part 15, which are evenly distributed in a cross-sectional plane over the circumference, to the annular groove 58, so that with a suitable rotational position of the distributor piston 18, an inlet bore 34 with the pump work space 28 is connected.
  • the inlet bores 34 open out in the interior 35 of the housing 11, which is filled with fuel by means of a feed pump 59 seated on the drive shaft 14, so that fuel can flow into the pump work chamber 28 via the inlet bore 34 during the suction stroke of the pump piston 21.
  • the amount of fuel delivered to the associated injection nozzle and injected there with each pump piston stroke is metered by means of a switching valve 36.
  • the switching valve 36 consists of an electromagnetically actuated valve member 37, which controls a valve opening 38, via which the pump working chamber 28 can be closed in order to build up pressure or be opened for sudden pressure reduction.
  • the valve opening 38 and the valve member 37 are integrated in the distributor piston 18.
  • this is provided with an axial relief bore 39, which opens at the lower end face of the distributor piston 18 and is connected to the interior 35 of the housing 11 via a recess 40 in the drive shaft 14.
  • the relief bore 39 opens into the valve chamber 31 via the valve opening 38.
  • the clear width of the valve opening 38 is selected to be smaller than the bore diameter of the relief bore 39 (see Fig. 2).
  • valve opening 38 is enclosed by a valve seat 41, on which the front end of the valve member 37 designed as a valve needle is pressed in the valve closed state.
  • the shaft 371 of the valve member 37 is displaceably in a guide bore 42 aligned with the relief bore 39.
  • This guide bore 42 runs through the distributor piston 18 from the valve chamber 31 to the upper end face.
  • a valve spring 43 which is biased in the valve opening direction and which is supported on the one hand on the end face of the distributor piston 18 and on the other hand on a stop 44 held on the valve member 37, for example a retaining ring.
  • the end of the valve member 37 facing away from the valve opening 38 bears against the rounded end of a plunger 45, which is connected to the armature 46 of an electromagnet 47 to close the switching valve 36.
  • the electromagnet 47 is constructed in a known manner and is described in detail, for example, in DE-OS 35 23 536. In short, this has a coil 49 received by a core 48, the winding ends of which are connected to two connecting plugs 50.
  • the plate-shaped anchor 46 connected to the plunger 45 lies opposite the core 48, which is covered with a disk 53, with the formation of two air gaps 51, 52.
  • the plunger 45 is axially displaceably guided in a central housing section 54 of the magnet housing 55 which carries the core 48, a return spring 56 being supported between the armature 46 and the housing section 54.
  • a stroke stop 57 limits the stroke movement of the armature 46 which, when the coil 49 is de-energized, bears against the stroke stop 57 under the action of the return spring 56.
  • the pump pistons 21 - controlled by the cam track 24 of the cam ring 25 - execute a reciprocating stroke movement.
  • the distributor piston 18 connects, successively and alternately, the pump work chamber 28 delimited by the pump piston 21 with one of the inlet bores 34 and one of the injection bores 29.
  • the cam track 24 is designed such that the pump work chamber 28 during a suction stroke of a pump piston 21 via the inlet groove 33 with an inlet bore 34 and is connected to the injection bore 29 via the distributor groove 32 during a delivery stroke of the pump piston 21.
  • the coil 49 of the electromagnet 47 is energized at the beginning of the delivery stroke.
  • the armature 46 is attracted against the restoring force of the restoring spring 56 and presses the valve member 37 onto the valve seat 41 via the tappet 45.
  • the valve opening 38 is thus closed and the relief bore 39 is separated from the pump work chamber 28.
  • the fuel pressure now building up in the pump work chamber 28 continues up to the injection nozzle and, after the opening pressure of the injection nozzle has been overcome, causes fuel to be injected into the combustion chamber of the diesel engine.
  • the power supply to the electromagnet 47 is switched off.
  • the armature 48 rests against the stroke stop 57 under the action of the return spring 56.
  • the valve member 37 lifts off from the valve seat 41 under the action of the valve spring 43 and releases the valve opening 38.
  • the pump working chamber 28 is thus via the annular groove 58, valve groove 32, valve bore 30, valve chamber 31 and valve opening 38 with the relief bore 39 connected.
  • the pressure in the pump working chamber 28 drops suddenly and the injection nozzle closes, so that the injection is ended.
  • the section of the valve member 37 located in the valve chamber 31 is advantageously shaped so that the pressure building up in the valve chamber 31 loads the valve member 37 in the opening direction. This ensures an abrupt opening of the switching valve 36 when the electromagnet 47 is switched off.
  • valve spring 43 which is designed as a helical compression spring in the exemplary embodiment in FIGS. 1 and 2 is replaced by a plate spring.
  • This disc spring is preferably designed as an elastic plastic disc.
  • Such a plate spring has a lower overall height than a helical compression spring, so that indentations on the end faces of the distributor piston 18 and the housing section 54 of the magnet housing 55, as are provided in FIGS. 1 and 2 for the purpose of reducing the axial overall height, can be dispensed with.

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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 fuel injection pump of the dispensing type comprises at least one axially-driven piston (21) which limits a working chamber (28) of the pump which can be connected to a fuel feed line and which conveys to an injector, at each delivery stroke, a quantity of fuel at injection pressure, a rotary dispensing piston (18) which, by turning, connects the work chamber (28) of the pump to an injector by means of a dispensing boring (30, 32), and a switching valve (36) serving to meter the quantity of fuel injected. To reduce the unused space in the working chamber (28) of the pump, at least the opening (38) of the switching valve (36) and valve unit (37) controlling the opening of the valve (38) are integrated in the dispensing piston (18). The opening of the valve (38) forms a connection between the dispensing boring (30, 32) and a discharge bore (39) of the dispensing piston which leads to a discharge aperture (40).

Description

Stand der TechnikState of the art

Die Erfindung geht aus von einer Kraftstoffeinspritzpumpe der Verteilerbauart zur Versorgung einer Mehrzahl von Einspritzdüsen einer Brennkraftmaschine, insbesondere einer Dieselbrennkraftmaschine, der im Oberbegriff des Anspruchs 1 definierten Gattung.The invention is based on a fuel injection pump of the distributor type for supplying a plurality of injection nozzles of an internal combustion engine, in particular a diesel internal combustion engine, of the type defined in the preamble of claim 1.

Bei einer bekannten Kraftstoffeinspritzpumpe dieser Art (US-A-4 552 117) ist im Bereich eines die radial gelagerten Pumpen­kolben aufnehmenden Bundes des Verteilerkolbens achsparallel zur Verteilerkolbenachse ein Drehschieber gelagert, der über ein Plane­tenradgetriebe bei der Drehung des Verteilerkolbens angetrieben wird und mit Ausnehmungen von in Achsrichtung variabler Breite zur Steu­erung einer Entlastungsleitung des Pumpenarbeitsraumes versehen ist.In a known fuel injection pump of this type (US-A-4 552 117), in the area of a radially mounted pump piston receiving collar of the distributor piston axially parallel to the distributor piston axis, a rotary valve is mounted, which is driven by a planetary gear during the rotation of the distributor piston and with recesses from in Axial direction of variable width is provided for controlling a relief line of the pump work space.

Das als Drehschieber ausgebildete Ventilglied wird insbesondere zur Steuerung der Kraftstoffeinspritzmenge durch einen Elektromagneten längs verschoben, während es bei seiner Drehbewegung den Spritzbe­ginn und auch die Spritzdauer steuert. Zur Verwirklichung dieses Prinzips bedarf es eines großen konstruktiven Aufwandes und einer genauen Synchronisation des Drehantriebes des Drehschiebers. Bei der kleinen Baugröße des Drehschiebers steht ferner nur eine geringe überdeckungsbreite, die die Dichtheit des Ventiles zu Schließzeiten gewährleisten soll, zur Verfügung. Dies ist bei dem einerseits not­wendigen Bewegungsspiel in Längs- und Umfangsrichtung des Drehschie­bers und dem hohen Kraftstoffdruck des zu steuernden Kraftstoffes problematisch.The valve member, which is designed as a rotary slide valve, is longitudinally displaced by an electromagnet, in particular for controlling the fuel injection quantity, while it controls the start of injection and also the duration of the injection when it rotates. In order to implement this principle, a great deal of design effort and precise synchronization of the rotary drive of the rotary valve is required. With the small size of the rotary valve, there is also only a small overlap width, which should ensure the tightness of the valve at closing times. This is problematic due to the necessary play in the longitudinal and circumferential directions of the rotary valve and the high fuel pressure of the fuel to be controlled.

Aufgabe der Erfindung ist es, die eingangs genannte Kraftstoffein­spritzpumpe so weiterzubilden, daß eine genaue und einfach zu ver­wirklichende Steuerung der Kraftstoffeinspritzung erzielt wird.The object of the invention is to develop the fuel injection pump mentioned at the outset in such a way that precise and easy-to-implement control of the fuel injection is achieved.

Vorteile der ErfindungAdvantages of the invention

Die erfindungsgemäße Kraftstoffeinspritzpumpe mit den Kennzeichnenden Merkmalen des Anspruchs 1 hat den Vorteil eines extrem verringerten Totvolumens im Pumpenarbeitsraum und eines geringen Raumbedarfs. Anstelle des kompletten EleKtroventils ist im Pumpengehäuse selbst nur noch der einfache Elektromagnet vorhanden. Bohrungen im Pumpengehäuse zum Anschluß des Schaltventils entfallen.The fuel injection pump according to the invention with the characterizing features of claim 1 has the advantage of an extremely reduced dead volume in the pump work space and a small space requirement. Instead of the complete electro valve, only the simple electromagnet is present in the pump housing itself. There are no holes in the pump housing for connecting the switching valve.

Durch die in den weiteren Anssprüchen aufgeführten Maßnahmen sind vorteilhafte Weiterbildungen und Verbesserungen der im Anspruch 1 angegebenen Kraftstoffeinspritzpumpe möglich.The measures listed in the further claims allow advantageous developments and improvements of the fuel injection pump specified in claim 1.

Zeichnungdrawing

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

  • Fig. 1 einen Längsschnitt einer Kraftstoffeinspritzpumpe der Verteilerbauart für eine Dieselbrennkraftmaschine,
  • Fig. 2 eine vergrößerte Darstellung von Schaltventil und Verteilerkolben der Kraftstoffeinspritzpumpe in Fig. 1,
  • Fig. 3 einen durch III in Fig. 2 gekennzeichneten Ausschnitt einer Kraftstoffeinspritzpumpe gemäß einem weiteren Ausführungsbeispiel.
The invention is explained in more detail in the following description with reference to exemplary embodiments shown in the drawing. Show it:
  • 1 shows a longitudinal section of a fuel injection pump of the distributor type for a diesel internal combustion engine,
  • 2 is an enlarged view of the switching valve and distributor piston of the fuel injection pump in Fig. 1,
  • 3 shows a section of a fuel injection pump according to a further exemplary embodiment, identified by III in FIG. 2.

Beschreibung der AusführungsbeispieleDescription of the embodiments

Die in Fig. 1 im Längsschnitt dargestellte Kraftstoffeinspritzpumpe der Verteilerbauart ist eine Radialkolbenpumpe zur Versorgung von insgesamt vier Einspritzdüsen eines Dieselmotors mit unter Einspritzdruck stehendem Kraftstoff vorgebener Zumessung. Die Kraftstoffeinspritzpumpe weist ein Gehäuse 11 auf, das von einem Gehäusedeckel 12 flüssigkeitsdicht abgeschlossen ist. In dem Gehäuse 11 ist mittels eines Lagers 13 eine Antriebswelle 14 drehbar gelagert. Ein am Gehäusedeckel 12 narbenartig vorstehender Deckelteil 15 ist mit einer axialen Zylinderbohrung 16 und insgesamt vier in einer Querschnittsebene gleichmäßig gegeneinander versetzten Radialbohrungen 17 versehen, von denen in Fig. 1 zwei Radialbohrungen 17 zu sehen sind. In der Zylinderbohrung 16 ist ein Verteilerkolben 18 gelagert, der mit der Antriebswelle 14 drehfest gekoppelt ist. Die Kopplung erfolgt dabei über Kupplungselemente 19, die in Nuten in der Antriebswelle 14 einerseits und in dem Verteilerkolben 18 andererseits formschlüssig einliegen. Der Verteilerkolben 18 ist in seiner Axialstellung durch einen Sicherungsring 20 gesichert.The fuel injection pump of the distributor type shown in longitudinal section in FIG. 1 is a radial piston pump for supplying a total of four injection nozzles of a diesel engine with predetermined fuel metering under injection pressure. The fuel injection pump has a housing 11 which is closed in a liquid-tight manner by a housing cover 12. A drive shaft 14 is rotatably mounted in the housing 11 by means of a bearing 13. A cover part 15 protruding in a scar-like manner on the housing cover 12 is provided with an axial cylinder bore 16 and a total of four radial bores 17 which are uniformly offset in relation to one another in a cross-sectional plane, of which two radial bores 17 can be seen in FIG. 1. In the cylinder bore 16 is a distributor piston 18 which is rotatably coupled to the drive shaft 14. The coupling takes place via coupling elements 19 which lie in a form-fitting manner in grooves in the drive shaft 14 on the one hand and in the distributor piston 18 on the other hand. The distributor piston 18 is secured in its axial position by a locking ring 20.

In den Radialbohrungen 17 ist jeweils ein Pumpenkolben 21 dicht geführt, der aus der Radialbohrung 17 vorsteht und dort mit einer Stößeltasse 22 verbunden ist. Die Stößeltasse 22 liegt über eine Walze oder Rolle 23 an der Nockenbahn 24 eines mit der Antriebswelle 14 drehfest verbundenen Nockenrings 25 an. Stößeltasse 22 und Rolle 23 bilden einen sog. Rollenstößel, der in einem zur Radialbohrung 17 koaxialen Führungsschacht 26 verschiebbar ist, so daß die Baueinheit aus Rolle 23, Stößeltasse 22 und Pumpenkolben 21 bei der Rotation des Nockenrings 25 den Erhebungen und Vertiefungen der Nockenbahn 24 zu folgen vermag. Für die kraftschlüssige Anlage der Stößeltasse 22 an der Rolle 23 und der Rolle 23 an der Nockenbahn 24 sorgt eine am Grund des Führungsschachtes 26 und im Innern der Stößeltasse 22 sich abstützende Schraubendruckfeder 27.In each of the radial bores 17, a pump piston 21 is sealingly guided, which projects out of the radial bore 17 and is connected there to a tappet cup 22. The tappet cup 22 abuts a cam or roller 23 on the cam track 24 of a cam ring 25 connected in a rotationally fixed manner to the drive shaft 14. Tappet cup 22 and roller 23 form a so-called roller tappet, which is displaceable in a guide shaft 26 coaxial with the radial bore 17, so that the assembly of roller 23, tappet cup 22 and pump piston 21 during the rotation of the cam ring 25 to the elevations and depressions of the cam track 24 can follow. A helical compression spring 27, which is supported on the base of the guide shaft 26 and in the interior of the tappet cup 22, ensures the frictional engagement of the tappet cup 22 on the roller 23 and the roller 23 on the cam track 24.

Jeder Pumpenkolben 21 begrenzt auf seiner Innenseite einen Pumpenarbeitsraum 28, der zum Verteilerkolben 18 hin offen und dort von einer Ringnut 58 auf dem Verteilerkolben 18 begrenzt ist. In einer oberhalb des Pumpenarbeitsraums 28 liegenden Querschnittsebene des Gehäusedeckels 12 münden in der Zylinderbohrung 16 vier über den Umfang gleichmäßig verteilte Einspritzbohrungen 29, von denen jeweils eine zu einer von insgesamt vier Einspritzdüsen führt. Der Verteilerkolben 18 enthält eine Verteilerbohrung 30, die im Innern des Verteilerkolbens 18 in einem Ventilraum 31 und am Umfang des Verteilerkolbens 18 in einer Verteilernut 32 mündet. Die axiale Länge der Verteilernut 32 ist so bemessen, daß sie von der Ringnut 58 bis hin zu den Mündungen der Einspritzbohrungen 29 reicht, und bei geeigneter Drehstellung des Verteilerkolbens 18 den Pumpenarbeitsraum 28 mit einer Einspritzbohrung 29 verbindet. Der Verteilerkolben 18 enthält ferner eine axiale Zulaufnut 33, die sich von in einer Querschnittsebene über den Umfang gleichmäßig verteilten vier radialen Zulaufbohrungen 34 im Deckelteil 15 bis hin zu der Ringnut 58 erstreckt, so daß bei geeigneter Drehstellung des Verteilerkolbens 18 eine Zulaufbohrung 34 mit dem Pumpenarbeitsraum 28 verbunden ist. Die Zulaufbohrungen 34 münden im Innenraum 35 des Gehäuses 11, der mittels einer auf der Antriebswelle 14 sitzenden Förderpumpe 59 mit Kraftstoff gefüllt ist, so daß beim Saughub des Pumpenkolbens 21 Kraftstoff über die Zulaufbohrung 34 in den Pumpenarbeitsraum 28 einströmen kann.Each pump piston 21 delimits on its inside a pump working chamber 28 which is open towards the distributor piston 18 and is delimited there by an annular groove 58 on the distributor piston 18. In a cross-sectional plane of the housing cover 12 lying above the pump work chamber 28, four injection bores 29, each of which leads uniformly distributed over the circumference, open into the cylinder bore 16, one of which leads to one of a total of four injection nozzles. The distributor piston 18 contains a distributor bore 30, which in the interior of the distributor piston 18 in a valve chamber 31 and on the circumference of the distributor piston 18 in a distributor groove 32 flows. The axial length of the distributor groove 32 is dimensioned such that it extends from the annular groove 58 to the mouths of the injection bores 29, and connects the pump working chamber 28 to an injection bore 29 when the distributor piston 18 is suitably rotated. The distributor piston 18 also contains an axial inlet groove 33, which extends from four radial inlet bores 34 in the cover part 15, which are evenly distributed in a cross-sectional plane over the circumference, to the annular groove 58, so that with a suitable rotational position of the distributor piston 18, an inlet bore 34 with the pump work space 28 is connected. The inlet bores 34 open out in the interior 35 of the housing 11, which is filled with fuel by means of a feed pump 59 seated on the drive shaft 14, so that fuel can flow into the pump work chamber 28 via the inlet bore 34 during the suction stroke of the pump piston 21.

Die bei jedem Pumpenkolbenhub zu der zugeordneten Einspritzdüse geförderte und dort zur Einspritzung gelangende Kraftstoffmenge wird mittels eines Schaltventils 36 zugemessen. Das Schaltventil 36 besteht aus einem elektromagnetisch betätigtem Ventilglied 37, das eine Ventilöffnung 38 steuert, über welche jeweils der Pumpenarbeitsraum 28 zum Druckaufbau verschlossen oder zum schlagartigen Druckabbau geöffnet werden kann. Die Ventilöffnung 38 und das Ventilglied 37 sind in dem Verteilerkolben 18 integriert. Hierzu ist dieser mit einer axialen Entlastungsbohrung 39 versehen, die an der unteren Stirnseite des Verteilerkolbens 18 mündet und über eine Ausnehmung 40 in der Antriebswelle 14 mit dem Innenraum 35 des Gehäuses 11 in Verbindung steht. Die Entlastungsbohrung 39 mündet über die Ventilöffnung 38 in dem Ventilraum 31. Die lichte Weite der Ventilöffnung 38 ist kleiner gewählt als der Bohrungsdurchmesser der Entlastungsbohrung 39 (vergl. Fig. 2). Die Ventilöffnung 38 wird von einem Ventilsitz 41 umschlossen, auf welcher das vordere Ende des als Ventilnadel ausgebildeten Ventilgliedes 37 im Ventilschließzustand aufgepreßt wird. Der Schaft 371 des Ventilgliedes 37 liegt in einer mit der Entlastungsbohrung 39 fluchtenden Führungsbohrung 42 verschieblich ein. Diese Führungsbohrung 42 durchzieht den Verteilerkolben 18 von dem Ventilraum 31 bis zur oberen Stirnseite. Auf dem aus der Führungsbohrung 42 vorstehenden Schaftabschnitt des Ventilgliedes 37 sitzt eine in Ventilöffnungsrichtung vorgespannte Ventilfeder 43, die sich einerseits auf der Stirnseite des Verteilerkolbens 18 und andererseits auf einen am Ventilglied 37 gehaltenen Anschlag 44, z.B. einem Sicherungsring, abstützt. Unter der Wirkung dieser Ventilfeder 43 liegt das von der Ventilöffnung 38 abgekehrte Stirnende des Ventilgliedes 37 an dem abgerundeten Ende eines Stößels 45 an, der zum Schließen des Schaltventils 36 mit dem Anker 46 eines Elektromagneten 47 verbunden ist.The amount of fuel delivered to the associated injection nozzle and injected there with each pump piston stroke is metered by means of a switching valve 36. The switching valve 36 consists of an electromagnetically actuated valve member 37, which controls a valve opening 38, via which the pump working chamber 28 can be closed in order to build up pressure or be opened for sudden pressure reduction. The valve opening 38 and the valve member 37 are integrated in the distributor piston 18. For this purpose, this is provided with an axial relief bore 39, which opens at the lower end face of the distributor piston 18 and is connected to the interior 35 of the housing 11 via a recess 40 in the drive shaft 14. The relief bore 39 opens into the valve chamber 31 via the valve opening 38. The clear width of the valve opening 38 is selected to be smaller than the bore diameter of the relief bore 39 (see Fig. 2). The valve opening 38 is enclosed by a valve seat 41, on which the front end of the valve member 37 designed as a valve needle is pressed in the valve closed state. The shaft 371 of the valve member 37 is displaceably in a guide bore 42 aligned with the relief bore 39. This guide bore 42 runs through the distributor piston 18 from the valve chamber 31 to the upper end face. On the stem section of the valve member 37 protruding from the guide bore 42 is seated a valve spring 43 which is biased in the valve opening direction and which is supported on the one hand on the end face of the distributor piston 18 and on the other hand on a stop 44 held on the valve member 37, for example a retaining ring. Under the action of this valve spring 43, the end of the valve member 37 facing away from the valve opening 38 bears against the rounded end of a plunger 45, which is connected to the armature 46 of an electromagnet 47 to close the switching valve 36.

Der Elektromagnet 47 ist in bekannter Weise aufgebaut und beispielsweise in der DE-OS 35 23 536 ausführlich beschrieben. Kurzgefaßt weist dieser eine von einem Kern 48 aufgenommene Spule 49 auf, deren Wicklungsenden mit zwei Anschlußsteckern 50 verbunden sind. Der mit dem Stößel 45 verbundene tellerförmige Anker 46 liegt unter Bildung zweier Luftspalte 51, 52 dem mit einer Scheibe 53 abgedeckten Kern 48 gegenüber. Der Stößel 45 ist in einem den Kern 48 tragenden zentrischen Gehäuseabschnitt 54 des Magnetgehäuses 55 axial verschieblich geführt, wobei sich eine Rückstellfeder 56 zwischen dem Anker 46 und dem Gehäuseabschnitt 54 abstützt. Ein Hubanschlag 57 begrenzt die Hubbewegung des Ankers 46, der bei stromloser Spule 49 unter der Wirkung der Rückstellfeder 56 an dem Hubanschlag 57 anliegt.The electromagnet 47 is constructed in a known manner and is described in detail, for example, in DE-OS 35 23 536. In short, this has a coil 49 received by a core 48, the winding ends of which are connected to two connecting plugs 50. The plate-shaped anchor 46 connected to the plunger 45 lies opposite the core 48, which is covered with a disk 53, with the formation of two air gaps 51, 52. The plunger 45 is axially displaceably guided in a central housing section 54 of the magnet housing 55 which carries the core 48, a return spring 56 being supported between the armature 46 and the housing section 54. A stroke stop 57 limits the stroke movement of the armature 46 which, when the coil 49 is de-energized, bears against the stroke stop 57 under the action of the return spring 56.

Die Arbeitsweise der beschriebenen Kraftstoffeinspritzpumpe ist wie folgt:The operation of the fuel injection pump described is as follows:

Bei Rotation der Antriebswelle 14 führen die Pumpenkolben 21 _ gesteuert von der Nockenbahn 24 des Nockenrings 25 _ eine hin- und hergehende Hubbewegung aus. Der Verteilerkolben 18 verbindet nacheinander und abwechselnd den von den Pumpenkolben 21 begrenzten Pumpenarbeitsraum 28 mit einer der Zulaufbohrungen 34 und einer der Einspritzbohrungen 29. Die Nockenbahn 24 ist so ausgebildet, daß der Pumpenarbeitsraum 28 bei einem Saughub eines Pumpenkolbens 21 über die Zulaufnut 33 mit einer Zulaufbohrung 34 und bei einem Förderhub des Pumpenkolbens 21 über die Verteilernut 32 mit der Einspritzbohrung 29 verbunden ist. Nach Füllen des Pumpenarbeitsraums 28 mit Kraftstoff wird mit Beginn des Förderhubs die Spule 49 des Elektromagneten 47 bestromt. Der Anker 46 wird gegen die Rückstellkraft der Rückstellfeder 56 angezogen und preßt über den Stößel 45 das Ventilglied 37 auf den Ventilsitz 41 auf. Die Ventilöffnung 38 ist damit geschlossen und die Entlastungsbohrung 39 vom Pumpenarbeitsraum 28 getrennt. Der jetzt im Pumpenarbeitsraum 28 sich aufbauende Kraftstoffdruck setzt sich bis zur Einspritzdüse fort und bewirkt nach Überwindung des Öffnungsdruckes der Einspritzdüse das Einspritzen von Kraftstoff in den Brennraum des Dieselmotors.When the drive shaft 14 rotates, the pump pistons 21 - controlled by the cam track 24 of the cam ring 25 - execute a reciprocating stroke movement. The distributor piston 18 connects, successively and alternately, the pump work chamber 28 delimited by the pump piston 21 with one of the inlet bores 34 and one of the injection bores 29. The cam track 24 is designed such that the pump work chamber 28 during a suction stroke of a pump piston 21 via the inlet groove 33 with an inlet bore 34 and is connected to the injection bore 29 via the distributor groove 32 during a delivery stroke of the pump piston 21. After filling the pump work chamber 28 with fuel, the coil 49 of the electromagnet 47 is energized at the beginning of the delivery stroke. The armature 46 is attracted against the restoring force of the restoring spring 56 and presses the valve member 37 onto the valve seat 41 via the tappet 45. The valve opening 38 is thus closed and the relief bore 39 is separated from the pump work chamber 28. The fuel pressure now building up in the pump work chamber 28 continues up to the injection nozzle and, after the opening pressure of the injection nozzle has been overcome, causes fuel to be injected into the combustion chamber of the diesel engine.

Zur Beendigung der Einspritzung wird die Stromzufuhr zum Elektromagneten 47 abgeschaltet. Der Anker 48 legt sich unter der Wirkung der Rückstellfeder 56 an den Hubanschlag 57 an. Das Ventilglied 37 hebt unter der Wirkung der Ventilfeder 43 vom Ventilsitz 41 ab und gibt die Ventilöffnung 38 frei. Damit ist der Pumpenarbeitsraum 28 über Ringnut 58, Ventilnut 32, Ventilbohrung 30, Ventilraum 31 und Ventilöffnung 38 mit der Entlastungsbohrung 39 verbunden. Dadurch fällt der Druck im Pumpenarbeitsraum 28 schlagartig ab und die Einspritzdüse schließt, so daß die Einspritzung beendet ist. Es sei angemerkt, daß vorteilhaft der im Ventilraum 31 befindliche Abschnitt des Ventilgliedes 37 so geformt ist, daß der im Ventilraum 31 sich aufbauende Druck das Ventilglied 37 in Öffnungsrichtung belastet. Dadurch wird ein schlagartiges Öffnen des Schaltventils 36 beim Abschalten des Elektromagneten 47 sichergestellt.To end the injection, the power supply to the electromagnet 47 is switched off. The armature 48 rests against the stroke stop 57 under the action of the return spring 56. The valve member 37 lifts off from the valve seat 41 under the action of the valve spring 43 and releases the valve opening 38. The pump working chamber 28 is thus via the annular groove 58, valve groove 32, valve bore 30, valve chamber 31 and valve opening 38 with the relief bore 39 connected. As a result, the pressure in the pump working chamber 28 drops suddenly and the injection nozzle closes, so that the injection is ended. It should be noted that the section of the valve member 37 located in the valve chamber 31 is advantageously shaped so that the pressure building up in the valve chamber 31 loads the valve member 37 in the opening direction. This ensures an abrupt opening of the switching valve 36 when the electromagnet 47 is switched off.

In der in Fig. 3 ausschnittweise dargestellten Variante der Kraftstoffeinspritzpumpe ist lediglich die Ventilfeder 43, die bei dem Ausführungsbeispiel in Fig. 1 und 2 als Schraubendruckfeder ausgebildet ist, durch eine Tellerfeder ersetzt. Diese Tellerfeder ist vorzugsweise als elastische Kunststoffscheibe ausgebildet. Eine solche Tellerfeder hat eine geringere Bauhöhe als eine Schraubendruckfeder, so daß auf Einsenkungen an den Stirnseiten des Verteilerkolbens 18 und des Gehäuseabschnittes 54 des Magnetgehäuses 55, wie diese in Fig. 1 und 2 zwecks Verringerung der axialen Bauhöhe vorgesehen sind, verzichtet werden kann.In the variant of the fuel injection pump shown in detail in FIG. 3, only the valve spring 43, which is designed as a helical compression spring in the exemplary embodiment in FIGS. 1 and 2, is replaced by a plate spring. This disc spring is preferably designed as an elastic plastic disc. Such a plate spring has a lower overall height than a helical compression spring, so that indentations on the end faces of the distributor piston 18 and the housing section 54 of the magnet housing 55, as are provided in FIGS. 1 and 2 for the purpose of reducing the axial overall height, can be dispensed with.

Claims (9)

1. Fuel injection pump of distributor type for supplying a plurality of fuel injectors of an internal combustion engine, in particular a diesel internal combustion engine, having at least one pump piston (21), which is driven in its axial direction, delimits a pump working chamber (28) that can be connected to a fuel feed line, and with each delivery stroke delivers fuel at injection pressure to a fuel injector, having a rotating distributor piston (18) which when rotating produces via a distributor line (30) a connection between pump working chamber (28) and fuel injector, and having a valve element (37), which is arranged in the distributor piston (18), can be axially adjusted by means of an electro­magnet (47) against the force of a return spring (43), and controls a relief line (39) in the distributor piston (18) in order to meter the fuel injection quantity, characterized in that the valve element (37) is a part of a control valve and is displaceably arranged coaxially with the distributor piston (18) in an axial guide bore (42) thereof, and interacts at one end with a valve seat (41) delimiting a valve opening (38) in the relief line (39) and at its other end projects from the guide bore (42) to bear, under the action of the valve spring (43), on a tappet (45) actuated by the electromagnet (47).
2. Pump according to Claim 1, characterized in that the tappet (45) is connected to an armature (46) of the electromagnet (47) and is rounded at its end bearing on the valve element (37).
3. Pump according to Claim 1 or 2, characterized in that the valve spring (43) is supported, on the one hand, on a stop (44) projecting radially over the valve element (37) and, on the other hand, on the end face of the distributor piston (18).
4. Pump according to Claim 3, characterized in that the valve spring (43) is constructed as a helical pres­sure spring (Fig. 2).
5. Pump according to Claim 3, characterized in that the valve spring (43) is constructed as a plate spring (Fig. 3).
6. Pump according to one of Claims 1-5, charac­terized in that the relief line (39) is constructed as an axial bore, which is aligned with the guide bore (42) and which is delimited by a valve opening (38) preferably having a smaller inside width with respect to the bore diameter.
7. Pump according to Claim 6, characterized in that the guide bore (42) and the relief bore (39) with valve opening (38) end at diametrically opposite sides of a valve chamber (31) connected to the distributor bore (30, 32).
8. Pump according to Claim 7, characterized in that, in the region of the valve chamber (31), the valve element (37) is shaped in such a way that the pressure prevailing in the valve chamber (31) produces a force component acting in the valve opening direction at the valve element (37).
9. Pump according to one of Claims 1-8, charac­terized in that the pump piston (21) constructed as a radial piston and the pump working chamber (28) delimited by the latter are arranged at right angles to the axis of the distributor piston (18), and in that the pump piston (21) is driven by means of a roller tappet (22, 23) which rolls on a cam ring (25), of which the cam ring (25) or the entire unit comprising roller tappet (22, 23) and pump piston (21) rotates together with the distributor piston (18).
EP88904480A 1987-06-13 1988-05-28 Fuel injection pump Expired - Lifetime EP0318535B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3719832 1987-06-13
DE19873719832 DE3719832A1 (en) 1987-06-13 1987-06-13 FUEL INJECTION PUMP

Publications (2)

Publication Number Publication Date
EP0318535A1 EP0318535A1 (en) 1989-06-07
EP0318535B1 true EP0318535B1 (en) 1991-02-20

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ID=6329673

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EP88904480A Expired - Lifetime EP0318535B1 (en) 1987-06-13 1988-05-28 Fuel injection pump

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US (1) US4940036A (en)
EP (1) EP0318535B1 (en)
JP (1) JP2695886B2 (en)
DE (2) DE3719832A1 (en)
WO (1) WO1988009868A1 (en)

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GB8918429D0 (en) * 1989-08-12 1989-09-20 Lucas Ind Plc Fuel pumping apparatus
DE4001435A1 (en) * 1990-01-19 1991-07-25 Kloeckner Humboldt Deutz Ag CONTROL VALVE
US5220235A (en) * 1990-04-20 1993-06-15 Koito Manufacturing Co., Ltd. Discharge lamp device
US5215449A (en) * 1991-12-05 1993-06-01 Stanadyne Automotive Corp. Distributor type fuel injection pump
DE4142998C1 (en) * 1991-12-24 1993-07-22 Robert Bosch Gmbh, 7000 Stuttgart, De
DE19717494A1 (en) * 1997-04-25 1998-10-29 Bosch Gmbh Robert Distributor type fuel injection pump
US7736242B2 (en) * 2004-03-23 2010-06-15 Nike, Inc. System for determining performance characteristics of a golf swing
US7451741B1 (en) * 2007-10-31 2008-11-18 Caterpillar Inc. High-pressure pump
FR3137419B1 (en) * 2022-07-04 2024-07-05 Delphi Tech Ip Ltd Fuel pump for direct fuel injection for internal combustion engines and valve for such a pump.

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DE3523536A1 (en) * 1984-09-14 1986-03-27 Robert Bosch Gmbh, 7000 Stuttgart Electrically controlled fuel injection pump for internal combustion engines

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US4426983A (en) * 1980-10-04 1984-01-24 Lucas Industries Limited Liquid fuel pumping apparatus
US4501244A (en) * 1982-07-15 1985-02-26 Lucas Industries Public Limited Company Fuel injection pumping apparatus
DE3342993A1 (en) * 1982-12-06 1984-06-07 Nissan Motor Co., Ltd., Yokohama, Kanagawa CONTROL DEVICE FOR THE FUEL INJECTION AMOUNT IN AN INTERNAL COMBUSTION ENGINE
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JPH0658100B2 (en) * 1986-02-06 1994-08-03 日本電装株式会社 Distributed fuel injection pump
GB8613409D0 (en) * 1986-06-03 1986-07-09 Lucas Ind Plc Fuel injection pumps
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DE3523536A1 (en) * 1984-09-14 1986-03-27 Robert Bosch Gmbh, 7000 Stuttgart Electrically controlled fuel injection pump for internal combustion engines

Also Published As

Publication number Publication date
DE3861788D1 (en) 1991-03-28
JP2695886B2 (en) 1998-01-14
US4940036A (en) 1990-07-10
JPH01503634A (en) 1989-12-07
WO1988009868A1 (en) 1988-12-15
EP0318535A1 (en) 1989-06-07
DE3719832A1 (en) 1988-12-22

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