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EP1163439A1 - Fuel injection pump - Google Patents

Fuel injection pump

Info

Publication number
EP1163439A1
EP1163439A1 EP01905608A EP01905608A EP1163439A1 EP 1163439 A1 EP1163439 A1 EP 1163439A1 EP 01905608 A EP01905608 A EP 01905608A EP 01905608 A EP01905608 A EP 01905608A EP 1163439 A1 EP1163439 A1 EP 1163439A1
Authority
EP
European Patent Office
Prior art keywords
piston
spring
injection pump
starting
pump
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.)
Withdrawn
Application number
EP01905608A
Other languages
German (de)
French (fr)
Inventor
Wolfgang Fehlmann
Wolfgang Geiger
Stephan Jonas
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP1163439A1 publication Critical patent/EP1163439A1/en
Withdrawn legal-status Critical Current

Links

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
    • 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
    • F02M41/123—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 characterised by means for varying fuel delivery or injection timing
    • F02M41/128—Varying injection timing by angular adjustment of the face-cam or the rollers support
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D1/00—Controlling fuel-injection pumps, e.g. of high pressure injection type
    • F02D1/16—Adjustment of injection timing
    • F02D1/18—Adjustment of injection timing with non-mechanical means for transmitting control impulse; with amplification of control impulse
    • F02D1/183—Adjustment of injection timing with non-mechanical means for transmitting control impulse; with amplification of control impulse hydraulic
    • F02D2001/186—Adjustment of injection timing with non-mechanical means for transmitting control impulse; with amplification of control impulse hydraulic using a pressure-actuated piston for adjustment of a stationary cam or roller support

Definitions

  • the invention relates to a fuel injection pump with a housing, a metering pump and a spray adjuster for the metering pump, the spray adjuster having a piston which is acted upon by a return spring.
  • Such a fuel injection pump is known from DE 43 44 865 A1.
  • This fuel injection pump is a so-called distributor injection pump, in which a single pump piston of the metering pump is used to inject the correct amount of fuel into the corresponding cylinder of an internal combustion engine.
  • the pump piston makes as many strokes during one revolution of the drive shaft as there are cylinders to be supplied to the motor; the drive shaft of the fuel injection pump rotates at half the speed of the crankshaft of the engine.
  • the injection adjuster is provided, by means of which the injection timing can be adapted to the prevailing operating conditions of the engine. In the case of a distributor injection pump, this is done by kolbe ⁇ actuating cam ring, which is driven by the drive shaft, is adjusted relative to this by about + 10 °.
  • the piston which is pressed by the return spring against an end flange, is provided for adjusting the cam ring.
  • This position in contact with the end flange corresponds to a spray adjustment in the "late” direction.
  • the side of the piston opposite the return spring is acted upon by a pressurized fluid which is controlled by a control slide and provided by a pre-feed pump of the injection pump. From this it follows, however, that when the fuel injection pump is at a standstill, the piston of the injection adjuster is in the "late” position, since no fluid flow can be provided at standstill and thus only the force acting on the piston is provided by the return spring.
  • the disadvantage here is that the position of the piston of the injection adjuster, which is predetermined by the return spring, is not optimal at a standstill for starting an internal combustion engine supplied by the fuel injection pump.
  • the fuel injection pump according to the invention with the features of claim 1 has the advantage that the return spring counteracting the return spring keeps the piston of the spray adjuster in the optimal position for starting the internal combustion engine when the fuel injection pump is at a standstill and consequently no fluid flow to it Is available with which the piston could be acted upon.
  • This optimal position which is chosen in particular with regard to the starting behavior at low temperatures, can preferably be determined by coordinating the preload and the spring constants of the return spring and the starting spring.
  • the starting spring is arranged in the interior of the piston. This results in a particularly compact design.
  • the starting spring is supported at one end on the housing of the injection pump. This results in a simple, open construction with low additional costs.
  • the starting spring is supported at one end on an auxiliary piston which is slidably mounted in a receiving bore in the piston and is supported on the housing.
  • a locking ring can be arranged in the receiving bore, which limits the displaceability of the auxiliary piston.
  • FIG. 1 is a sectional view of a fuel injection pump.
  • FIG. 2 shows schematically a spray adjuster of a fuel injection pump according to the invention in a sectional view
  • FIG. 3 shows a detail of the piston of the spray adjuster according to a first embodiment in a sectional view
  • FIG. 4 shows a detail of the piston of the spray adjuster according to a second embodiment in a sectional view.
  • the fuel injection pump shown partially in axial longitudinal section in FIG. 1 has a housing 10 in which a drive shaft 11 with slide bearings 12 is rotatably mounted.
  • the housing 10 surrounds a pump interior 13 which is filled with fuel under pressure.
  • the filling of the pump interior 13 is achieved with the aid of a prefeed pump 14 which is arranged in the pump interior 13 and is driven by the drive shaft 11.
  • a pump piston 18 is coupled in a rotationally fixed manner to the front cam disk 17, which is pressed against the front cam disk 17 by a spring 19 and presses a cam track 20 arranged on the front cam disk 17 against rollers 21 which are mounted in a radial orientation in a roller ring 22. With its circular outer contour, the latter is rotatably mounted in a corresponding circular cylindrical recess 23 in the pump interior 13, wherein it is supported axially via a skirt 24 on a disk 25 covering the pre-feed pump 14.
  • the coupling formed by the pair of claws 15 and the driving piece 16 between the drive shaft 11 and the pump piston 18 protrudes through the roller ring 22.
  • the roller ring 22 is rotatably supported to a limited extent in the circumferential direction and is actuated by a spray adjuster 26 in a known manner.
  • the roller ring 22 is coupled to a piston 28 of the injection adjuster via a bolt 27 extending radially to the drive shaft 11.
  • the coupling takes place via a sliding block 29. 2 shows the spray adjuster with the piston 28.
  • the piston 28 is displaceable in a bore 30, so that two working spaces 32, 34 which are separated from one another by the piston 28 are formed and can each be supplied with fluid by a supply bore 36, 38.
  • a control slide 40 and a proportional magnet 42 are provided for controlling the corresponding fluid flow.
  • the piston 28 is provided on its two end faces with a receiving bore 44 or 46, which serves to receive a spring.
  • a return spring 48 is arranged in the receiving bore 44, which tries to urge the piston 28 downward with respect to FIG. 2 into a position in which the working space 34 has a minimal volume.
  • a starting spring 50 (not shown in FIG. 2) is arranged in the receiving bore 46, which counteracts the return spring 48 and thus acts on the piston in the direction of a reduction in the working space 32.
  • FIG. 3 shows the end of the piston 28 provided with the starting spring 50 in accordance with a first embodiment.
  • An auxiliary piston 52 is displaceably arranged in the receiving bore 46 in the piston 28 of the injection adjuster, the starting spring 50 being designed as a compression spring and being supported between the bottom of the receiving bore 46 and the head of the auxiliary piston 52.
  • the auxiliary piston 52 is urged into contact with the housing 10, a locking ring 54 being arranged in the receiving bore 46, which prevents the auxiliary piston 52 from being pressed out of the receiving bore 46 by the starting spring 50.
  • the auxiliary piston 52 is provided with a ventilation opening 56, so that the space in which the starting spring 50 is arranged is at the same pressure as the working space 34.
  • FIG. 4 is a second embodiment. of the piston 28 of the injection adjuster shown.
  • the starting spring 50 arranged in the receiving bore 46 is supported with its bottom the receiving bore opposite end directly from the housing 10, a spring plate 58 being provided which is arranged on a center nose 60 on the housing.
  • the function of the piston 28 of the injection adjuster which is provided with a return spring 48 and a starting spring 50, is as follows:
  • the piston 28 When the fuel injection pump is at a standstill, ie when no fluid is provided by the pre-feed pump 14 for pressurizing the working spaces 32, 34 via the supply bores 36, 38 the piston 28 is approximately in the position shown in FIG. 2, in which the starting spring 50 ensures that the piston 28 does not abut the bottom of the working space 34, as would be the case with an injection pump from the prior art.
  • the optimal starting early position of the fuel injection pump results for optimal engine starting conditions. After starting the internal combustion engine, there is first a speed that corresponds to the lower idling speed.
  • the working chamber 32 is acted upon by the control slide 40 with fluid, so that the piston 28 of the spray adjuster with respect to FIG. 2 is adjusted downward into the "late” position, in which it is pressed against the bottom of the working chamber 34 into the end position that he would have had without the presence of the starting spring 50 (0 ° NW). If the speed is increased further, the pressure chamber 34 is supplied with fluid by the control slide 40, so that the piston 28 is moved back in the "early” direction. At maximum speed, it is then at the end stop for the "early” position, which corresponds to approximately 20 ° NW.
  • the starting spring 50 is only effective over an adjustment range of approximately 5 ° NW due to the presence of the auxiliary piston 52 and the locking ring 54; with a larger adjustment of the piston 28, the auxiliary piston 52 lifts off the housing 10.
  • the particular advantage of this embodiment is the good design of the spring; it is disadvantageous, however, that the resultant of the piston 28 acting spring forces experience a kink in the area in which the auxiliary piston 52 lifts off the housing 10.
  • the starting spring 50 remains effective over the entire adjustment range of the piston 28.
  • the spring stability and the fatigue strength of the spring are critical in this embodiment.
  • the position of the piston 28 in the bore 30 results from the arrangement of the locking ring 54 in the receiving bore 46; assuming a sufficiently strong dimensioning of the starting spring 50, the piston 28 is pressed by the auxiliary spring 50 in the "early" direction until the auxiliary piston 52 abuts the locking ring 54.
  • the corresponding position of the piston 28 results as an equilibrium position between the forces of the return spring 48 and the starting spring 50.
  • Adjustment disks 62 can be used for the exact adjustment of this position, which are located between the bottom of the receiving bore 46 and the starting spring 50 can be arranged.
  • the injection adjuster arrangement described above can also be used for radial piston pumps.
  • the roller ring 22 is then replaced by a cam ring which has an articulation pin with an articulation ball.
  • the coupling takes place by engagement of the articulation ball of the articulation pin with a driving bush, which in turn is firmly pressed into a transverse bore of the injection adjuster piston.

Landscapes

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

Abstract

The invention relates to a fuel injection pump comprising a housing (10), a dosing pump (18, 20) and an injection control device (26) for the dosing pump. Said injection control device is provided with a piston (28) which is impinged upon by a return spring (48). The aim of the invention is to improve starting behaviour of the internal combustion engine that is supplied by the injection pump. A starting spring (50) is additionally provided which impinges upon the piston (28) and acts against the return spring.

Description

Kraftstoff-Einspritzpumpe Fuel injection pump
Stand der TechnikState of the art
Die Erfindung betrifft eine Kraftstoff-Einspritzpumpe mit einem Gehäuse, einer Dosierpumpe und einem Spritzversteller für die Dosierpumpe, wobei der Spritz- versteller einen Kolben aufweist, der von einer Rückstellfeder beaufschlagt wird.The invention relates to a fuel injection pump with a housing, a metering pump and a spray adjuster for the metering pump, the spray adjuster having a piston which is acted upon by a return spring.
Eine solche Kraftstoff-Einspritzpumpe ist aus der DE 43 44 865 A1 bekannt. Es handelt sich bei dieser Kraftstoff-Einspritzpumpe um eine sogenannte Ver- teilereinsphtzpumpe, bei der ein einziger Pumpenkolben der Dosierpumpe dazu verwendet wird, die korrekte Kraftstoffmenge in den entsprechenden Zylinder eines Verbrennungsmotors einzuspritzen. Der Pumpenkolben macht während einer Umdrehung der Antriebswelle so viele Hübe, wie Zylinder des Motors zu versorgen sind; die Antriebswelle der Kraftstoff-Einspritzpumpe dreht sich dabei mit der halben Drehzahl der Kurbelwelle des Motors.Such a fuel injection pump is known from DE 43 44 865 A1. This fuel injection pump is a so-called distributor injection pump, in which a single pump piston of the metering pump is used to inject the correct amount of fuel into the corresponding cylinder of an internal combustion engine. The pump piston makes as many strokes during one revolution of the drive shaft as there are cylinders to be supplied to the motor; the drive shaft of the fuel injection pump rotates at half the speed of the crankshaft of the engine.
Da der Kraftstoff in die entsprechenden Zylinder, bezogen auf den Drehwinkel der Kurbelwelle, nicht immer zu demselben Zeitpunkt eingespritzt werden muß, ist der Spritzversteller vorgesehen, mittels dem der Einspritzzeitpunkt an die herrschenden Betriebsbedingungen des Motors angepaßt werden kann. Bei einer Verteilereinspritzpumpe geschieht dies dadurch, daß ein den Pumpen- kolbeπ betätigender Nockenring, der von der Antriebswelle angetrieben wird, relativ zu dieser um etwa + 10° verstellt wird.Since the fuel does not always have to be injected into the corresponding cylinders, based on the angle of rotation of the crankshaft, the injection adjuster is provided, by means of which the injection timing can be adapted to the prevailing operating conditions of the engine. In the case of a distributor injection pump, this is done by kolbeπ actuating cam ring, which is driven by the drive shaft, is adjusted relative to this by about + 10 °.
Zur Verstellung des Nockenrings ist der Kolben vorgesehen, der von der Rück- stellfeder gegen einen Endanschiag gedrückt wird. Diese Stellung in Anlage am Endanschiag entspricht einer Spritzverstellung in Richtung "spät". Um nun beim Betrieb die Spritzverstellung hervorzurufen, wird die der Rückstellfeder gegenüberliegende Seite des Kolbens mit einem unter Druck stehenden Fluid beaufschlagt, das von einem Steuerschieber gesteuert und von einer Vorförderpumpe der Einspritzpumpe bereitgestellt wird. Hieraus folgt aber, daß bei Stillstand der Kraftstoff-Einspritzpumpe sich der Kolben des Spritzverstellers in der Lage "spät" befindet, da im Stillstand kein Fluidstrom bereitgestellt werden kann und somit auf den Kolben ausschließlich die Kraft einwirkt, die von der Rückstellfeder bereitgestellt wird.The piston, which is pressed by the return spring against an end flange, is provided for adjusting the cam ring. This position in contact with the end flange corresponds to a spray adjustment in the "late" direction. In order to bring about the spray adjustment during operation, the side of the piston opposite the return spring is acted upon by a pressurized fluid which is controlled by a control slide and provided by a pre-feed pump of the injection pump. From this it follows, however, that when the fuel injection pump is at a standstill, the piston of the injection adjuster is in the "late" position, since no fluid flow can be provided at standstill and thus only the force acting on the piston is provided by the return spring.
Nachteilig hierbei ist, daß die von der Rückstellfeder vorgegebene Lage des Kolbens des Spritzverstellers im Stillstand nicht optimal ist für das Starten eines von der Kraftstoff-Einspritzpumpe versorgten Verbrennungsmotors.The disadvantage here is that the position of the piston of the injection adjuster, which is predetermined by the return spring, is not optimal at a standstill for starting an internal combustion engine supplied by the fuel injection pump.
Vorteile der ErfindungAdvantages of the invention
Die erfiπdungsgemäße Kraftstoff-Einspritzpumpe mit den Merkmalen des Patentanspruchs 1 bietet den Vorteil, daß die der Rückstellfeder entgegenwirkende Startfeder den Kolben des Spritzverstellers in der für einen Start des Verbrennungsmotors optimalen Stellung hält, wenn sich die Kraftstoff-Einspritzpumpe im Stillstand befindet und folglich kein Fluidstrom zur Verfügung steht, mit dem der Kolben beaufschlagt werden könnte. Diese optimale Stellung, die insbesondere im Hinblick auf das Startverhalten bei niedrigen Temperaturen gewählt wird, kann vorzugsweise durch Abstimmung der Vorspannung und der Federkonstanten der Rückstellfeder und der Startfeder bestimmt werden. Gemäß einer bevorzugten Ausführungsform ist vorgesehen, daß die Startfeder im Inneren des Kolbens angeordnet ist. Dies ergibt eine besonders kompakte Bauform.The fuel injection pump according to the invention with the features of claim 1 has the advantage that the return spring counteracting the return spring keeps the piston of the spray adjuster in the optimal position for starting the internal combustion engine when the fuel injection pump is at a standstill and consequently no fluid flow to it Is available with which the piston could be acted upon. This optimal position, which is chosen in particular with regard to the starting behavior at low temperatures, can preferably be determined by coordinating the preload and the spring constants of the return spring and the starting spring. According to a preferred embodiment it is provided that the starting spring is arranged in the interior of the piston. This results in a particularly compact design.
Gemäß einer Ausführungsform ist vorgesehen, daß sich die Startfeder mit einem Ende am Gehäuse der Einspritzpumpe abstützt. Auf diese Weise ergibt sich eine einfache, offene Konstruktion mit geringen Zusatzkosten.According to one embodiment it is provided that the starting spring is supported at one end on the housing of the injection pump. This results in a simple, open construction with low additional costs.
Gemäß einer alternativen Ausführungsform ist vorgesehen, daß die Startfeder sich mit einem Ende an einem Hilfskolbeπ abstützt, der verschiebbar in einer Aufπahmebohruπg im Kolben gelagert ist und sich am Gehäuse abstützt. Bei dieser gekapselten Lösung ist nur eine vergleichsweise kurze Feder erforderlich, die gut ausgelegt werden kann.According to an alternative embodiment it is provided that the starting spring is supported at one end on an auxiliary piston which is slidably mounted in a receiving bore in the piston and is supported on the housing. This encapsulated solution only requires a comparatively short spring that can be designed well.
Um zu verhindern, daß sich der Hilfskolben von dem Kolben des Spritzverstellers löst, kann in der Aufnahmebohrung ein Sicherungsring angeordnet sein, der die Verschiebbarkeit des Hilfskolbens begrenzt.In order to prevent the auxiliary piston from detaching from the piston of the injection adjuster, a locking ring can be arranged in the receiving bore, which limits the displaceability of the auxiliary piston.
Beschreibung der ZeichnungenDescription of the drawings
Die Erfindung wird nachfolgend unter Bezugnahme auf zwei bevorzugte Ausführungsformen beschrieben, die in den beigefügten Zeichnungen dargestellt sind. In diesen zeigen:The invention is described below with reference to two preferred embodiments which are illustrated in the accompanying drawings. In these show:
- Fig. 1 in einer Schnittansicht eine Kraftstoff-Einspritzpumpe;- Figure 1 is a sectional view of a fuel injection pump.
- Fig. 2 in einer Schπittansicht schematisch einen Spritzversteller einer erfindungsgemäßen Kraftstoff-Einspritzpumpe;- FIG. 2 shows schematically a spray adjuster of a fuel injection pump according to the invention in a sectional view;
- Fig. 3 in einer Schnittansicht ein Detail des Kolbens des Spritzverstellers gemäß einer ersten Ausführungsform; und - Fig. 4 in einer Schnittansicht ein Detail des Kolbens des Spritzverstellers gemäß einer zweiten Ausführungsform. Beschreibung der Ausführungsbeispiele3 shows a detail of the piston of the spray adjuster according to a first embodiment in a sectional view; and FIG. 4 shows a detail of the piston of the spray adjuster according to a second embodiment in a sectional view. Description of the embodiments
Die in Fig. 1 teilweise im axialen Längsschnitt dargestellte Kraftstoff-Einspritz- pumpe weist ein Gehäuse 10 auf, in welchem eine Antriebswelle 11 mit Gleitlagern 12 drehbar gelagert ist. Das Gehäuse 10 umgibt einen Pumpeninπen- raum 13, der mit unter Druck stehendem Kraftstoff gefüllt ist. Die Füllung des Pumpeninnenraums 13 wird mit Hilfe einer Vorförderpumpe 14 erzielt, die im Pumpeπinnenraum 13 angeordnet ist und von der Antriebswelle 1 1 angetrieben wird.The fuel injection pump shown partially in axial longitudinal section in FIG. 1 has a housing 10 in which a drive shaft 11 with slide bearings 12 is rotatably mounted. The housing 10 surrounds a pump interior 13 which is filled with fuel under pressure. The filling of the pump interior 13 is achieved with the aid of a prefeed pump 14 which is arranged in the pump interior 13 and is driven by the drive shaft 11.
Am Ende der Antriebswelle 11 befindet sich stirnseitig ein Klaueπpaar 1 5, das über ein Mitnahmestück 16 und entsprechende, nicht dargestellte Klauen eine Stirnnockenscheibe 17 drehend antreibt. Mit der Stirnnockenscheibe 17 ist ein Pumpenkolben 18 drehfest gekoppelt, der durch eine Feder 19 an die Stirnnockenscheibe 17 gedrückt wird und eine auf der Stirnnockenscheibe 17 angeordnete Nockenbahn 20 gegen Rollen 21 drückt, die in radialer Ausrichtung in einem Rollenring 22 gelagert sind. Dieser ist mit seiner kreisförmigen Außenkontur in einer entsprechenden kreiszylindrischen Ausnehmung 23 im Pum- peninnenraum 13 drehbar gelagert, wobei er sich axial über eine Schürze 24 an einer die Vorförderpumpe 14 abdeckenden Scheibe 25 abstützt. Die von dem Klauenpaar 15 und dem Mitnahmestück 16 gebildete Kupplung zwischen Antriebswelle 11 und Pumpenkolben 18 ragt durch den Rollenriπg 22 hindurch.At the end of the drive shaft 11 there is a pair of claws 15 on the end face, which rotates a front cam disk 17 via a driving piece 16 and corresponding claws, not shown. A pump piston 18 is coupled in a rotationally fixed manner to the front cam disk 17, which is pressed against the front cam disk 17 by a spring 19 and presses a cam track 20 arranged on the front cam disk 17 against rollers 21 which are mounted in a radial orientation in a roller ring 22. With its circular outer contour, the latter is rotatably mounted in a corresponding circular cylindrical recess 23 in the pump interior 13, wherein it is supported axially via a skirt 24 on a disk 25 covering the pre-feed pump 14. The coupling formed by the pair of claws 15 and the driving piece 16 between the drive shaft 11 and the pump piston 18 protrudes through the roller ring 22.
Der Rollenriπg 22 ist in Umfangsrichtung begrenzt drehbar gelagert und wird durch einen Spritzversteller 26 in bekannter Weise betätigt. Dazu ist der Rollenring 22 über einen radial zur Antriebswelle 11 verlaufenden Bolzen 27 mit einem Kolben 28 des Spritzverstellers gekoppelt. Die Kopplung erfolgt dabei über einen Gleitstein 29. In Fig. 2 ist der Spritzversteller mit dem Kolben 28 zu sehen. Der Kolben 28 ist in einer Bohrung 30 verschiebbar, so daß zwei durch den Kolben 28 voneinander getrennte Arbeitsräume 32, 34 gebildet sind, die jeweils von einer Versor- gungsbohruπg 36, 38 mit Fluid versorgt werden können. Zur Steuerung des entsprechenden Fluidstromes sind ein Steuerschieber 40 sowie ein Proportionalmagnet 42 vorgesehen.The roller ring 22 is rotatably supported to a limited extent in the circumferential direction and is actuated by a spray adjuster 26 in a known manner. For this purpose, the roller ring 22 is coupled to a piston 28 of the injection adjuster via a bolt 27 extending radially to the drive shaft 11. The coupling takes place via a sliding block 29. 2 shows the spray adjuster with the piston 28. The piston 28 is displaceable in a bore 30, so that two working spaces 32, 34 which are separated from one another by the piston 28 are formed and can each be supplied with fluid by a supply bore 36, 38. A control slide 40 and a proportional magnet 42 are provided for controlling the corresponding fluid flow.
Der Kolben 28 ist auf seinen beiden Stirnseiten jeweils mit einer Aufnahme- bohruπg 44 bzw. 46 versehen, die zur Aufnahme einer Feder dient. In der Aufnahmebohrung 44 ist eine Rückstellfeder 48 angeordnet, die den Kolben 28 bezüglich Fig. 2 nach unten in eine Stellung zu beaufschlagen sucht, in welcher der Arbeitsraum 34 ein minimales Volumen aufweist. In der Aufnahmebohrung 46 ist eine (in Fig. 2 nicht gezeigte) Startfeder 50 angeordnet, die der Rückstellfeder 48 entgegenwirkt und somit den Kolben in Richtung einer Ver- kleinerung des Arbeitsraumes 32 beaufschlagt.The piston 28 is provided on its two end faces with a receiving bore 44 or 46, which serves to receive a spring. A return spring 48 is arranged in the receiving bore 44, which tries to urge the piston 28 downward with respect to FIG. 2 into a position in which the working space 34 has a minimal volume. A starting spring 50 (not shown in FIG. 2) is arranged in the receiving bore 46, which counteracts the return spring 48 and thus acts on the piston in the direction of a reduction in the working space 32.
In Fig. 3 ist das mit der Startfeder 50 versehene Ende des Kolbens 28 gemäß einer ersten Ausführungsform gezeigt. In der Aufπahmebohrung 46 im Kolben 28 des Spritzverstellers ist ein Hilfskolben 52 verschiebbar angeordnet, wobei die Startfeder 50 als Druckfeder ausgebildet ist und sich zwischen dem Boden der Aufπahmebohrung 46 und dem Kopf des Hilfskolbens 52 abstützt. Somit wird der Hilfskolbeπ 52 in Anlage an das Gehäuse 10 beaufschlagt, wobei in der Aufπahmebohruπg 46 ein Sicherungsring 54 angeordnet ist, der verhindert, daß der Hilfskolben 52 von der Startfeder 50 aus der Aufπahmebohrung 46 herausgedrückt wird. Der Hilfskolbeπ 52 ist mit einer Belüftuπgsöffπung 56 versehen, so daß der Raum, in welchem die Startfeder 50 angeordnet ist, sich auf demselben Druck befindet wie der Arbeitsraum 34.3 shows the end of the piston 28 provided with the starting spring 50 in accordance with a first embodiment. An auxiliary piston 52 is displaceably arranged in the receiving bore 46 in the piston 28 of the injection adjuster, the starting spring 50 being designed as a compression spring and being supported between the bottom of the receiving bore 46 and the head of the auxiliary piston 52. Thus, the auxiliary piston 52 is urged into contact with the housing 10, a locking ring 54 being arranged in the receiving bore 46, which prevents the auxiliary piston 52 from being pressed out of the receiving bore 46 by the starting spring 50. The auxiliary piston 52 is provided with a ventilation opening 56, so that the space in which the starting spring 50 is arranged is at the same pressure as the working space 34.
In Fig. 4 ist eine zweite Ausführungsform. des Kolbens 28 des Spritzverstellers gezeigt. Im Unterschied zur in Fig. 3 gezeigten Ausfύhrungsform stützt sich die in der Aufπahmebohrung 46 angeordnete Startfeder 50 mit ihrem dem Boden der Aufnahmebohruπg gegenüberliegenden Ende unmittelbar am Gehäuse 10 ab, wobei ein Federteller 58 vorgesehen ist, der auf einer Zeπtriemase 60 am Gehäuse angeordnet ist.4 is a second embodiment. of the piston 28 of the injection adjuster shown. In contrast to the embodiment shown in FIG. 3, the starting spring 50 arranged in the receiving bore 46 is supported with its bottom the receiving bore opposite end directly from the housing 10, a spring plate 58 being provided which is arranged on a center nose 60 on the housing.
Die Funktionsweise des mit Rückstellfeder 48 und Startfeder 50 versehenen Kolbens 28 des Spritzverstellers ist die folgende: Im Stillstand der Kraftstoff- Einspritzpumpe, wenn also über die Versorgungsbohrungeπ 36, 38 kein Fluid von der Vorförderpumpe 14 zur Druckbeaufschlagung der Arbeitsräume 32, 34 bereitgestellt wird, befindet sich der Kolben 28 etwa in der in Fig. 2 gezeigten Stellung, in welcher die Startfeder 50 gewährleistet, daß der Kolben 28 nicht am Boden des Arbeitsraumes 34 anliegt, wie dies bei einer Einspritzpumpe aus dem Stand der Technik der Fall wäre. In dieser Stellung des Kolbens 28 ergibt sich die optimale Startfrühlage der Kraftstoff-Einspritzpumpe für optimale Motorstartbediπguπgen. Nach dem Starten des Verbrennungsmotors ergibt sich zunächst eine Drehzahl, die der unteren Leerlaufdrehzahl entspricht. Dabei wird zunächst der Arbeitsraum 32 von dem Steuerschieber 40 mit Fluid beaufschlagt, so daß sich der Kolben 28 des Spritzverstellers bezüglich Fig. 2 nach unten in die Lage "spät" verstellt, in der er an den Boden des Arbeitsraurnes 34 in die Endstellung gedrückt wird, die er ohne das Vorhandensein der Startfeder 50 hätte (0° NW). Wenn die Drehzahl weiter gesteigert wird, wird der Druckraum 34 vom Steuerschieber 40 mit Fluid versorgt, so daß der Kolben 28 zurück Richtung "früh" bewegt wird. Bei maximaler Drehzahl befindet er sich dann am Endanschlag für die Stellung "früh", was etwa 20° NW entspricht.The function of the piston 28 of the injection adjuster, which is provided with a return spring 48 and a starting spring 50, is as follows: When the fuel injection pump is at a standstill, ie when no fluid is provided by the pre-feed pump 14 for pressurizing the working spaces 32, 34 via the supply bores 36, 38 the piston 28 is approximately in the position shown in FIG. 2, in which the starting spring 50 ensures that the piston 28 does not abut the bottom of the working space 34, as would be the case with an injection pump from the prior art. In this position of the piston 28, the optimal starting early position of the fuel injection pump results for optimal engine starting conditions. After starting the internal combustion engine, there is first a speed that corresponds to the lower idling speed. First of all, the working chamber 32 is acted upon by the control slide 40 with fluid, so that the piston 28 of the spray adjuster with respect to FIG. 2 is adjusted downward into the "late" position, in which it is pressed against the bottom of the working chamber 34 into the end position that he would have had without the presence of the starting spring 50 (0 ° NW). If the speed is increased further, the pressure chamber 34 is supplied with fluid by the control slide 40, so that the piston 28 is moved back in the "early" direction. At maximum speed, it is then at the end stop for the "early" position, which corresponds to approximately 20 ° NW.
Bei der in Fig. 3 gezeigten Ausführungsform ist die Startfeder 50 aufgrund des Vorhandenseins des Hilfskolbens 52 und des Sicherungsringes 54 nur über einen Versteilbereich von ca. 5° NW wirksam; bei einer größeren Verstellung des Kolbens 28 hebt der Hilfskolben 52 vom Gehäuse 10 ab. Der besondere Vorteil dieser Ausführungsform besteht in der guten Auslegbarkeit der Feder; nachteilig ist allerdings, daß die Resultierende der auf den Kolben 28 einwirkendeπ Federkräfte einen Knick erfährt in dem Bereich, in welchem der Hilfskolben 52 vom Gehäuse 10 abhebt.In the embodiment shown in FIG. 3, the starting spring 50 is only effective over an adjustment range of approximately 5 ° NW due to the presence of the auxiliary piston 52 and the locking ring 54; with a larger adjustment of the piston 28, the auxiliary piston 52 lifts off the housing 10. The particular advantage of this embodiment is the good design of the spring; it is disadvantageous, however, that the resultant of the piston 28 acting spring forces experience a kink in the area in which the auxiliary piston 52 lifts off the housing 10.
Bei der in Fig. 4 gezeigten Ausführuπgsform bleibt die Startfeder 50 über den gesamten Verstellbereich des Kolbens 28 wirksam. Kritisch bei dieser Ausführungsform ist jedoch die Federstabilität und die Dauerfestigkeit der Feder.In the embodiment shown in FIG. 4, the starting spring 50 remains effective over the entire adjustment range of the piston 28. However, the spring stability and the fatigue strength of the spring are critical in this embodiment.
Bei der in Fig. 3 gezeigten Ausführungsform ergibt sich die Lage des Kolbens 28 in der Bohrung 30 durch die Anordnung des Sicherungsringes 54 in der Auf- πahmebohrung 46; unter der Annahme einer ausreichend starken Dimensionierung der Startfeder 50 wird der Kolben 28 von der Hilfsfeder 50 so weit Richtung "früh" gedrückt, bis der Hilfskolben 52 am Sicherungsring 54 anliegt. Bei der in Fig. 4 gezeigten Ausführungsform ergibt sich die entsprechende Lage des Kolbens 28 als Gleichgewichtsstellung zwischen den Kräften der Rück- stellfeder 48 und der Startfeder 50. Zur genauen Justierung dieser Stellung können Einstellscheiben 62 verwendet werden, die zwischen dem Boden der Aufnahmebohruπg 46 und der Startfeder 50 angeordnet werden.In the embodiment shown in FIG. 3, the position of the piston 28 in the bore 30 results from the arrangement of the locking ring 54 in the receiving bore 46; assuming a sufficiently strong dimensioning of the starting spring 50, the piston 28 is pressed by the auxiliary spring 50 in the "early" direction until the auxiliary piston 52 abuts the locking ring 54. In the embodiment shown in FIG. 4, the corresponding position of the piston 28 results as an equilibrium position between the forces of the return spring 48 and the starting spring 50. Adjustment disks 62 can be used for the exact adjustment of this position, which are located between the bottom of the receiving bore 46 and the starting spring 50 can be arranged.
Die vorstehend beschriebene Spritzverstelleranordnung kann auch für Radial- Kolbenpumpen verwendet werden. Der Rollenring 22 wird dann durch einen Nockenring ersetzt, der einen Aπlenkbolzen mit Aπlenkkugel aufweist. Die Kopplung erfolgt durch Eingriff der Anlenkkugel des Anleπkbolzens mit einer Mitπehmerbuchse, die wiederum fest in eine Querbohrung des Spritzversteller- kolbens eingepreßt ist. The injection adjuster arrangement described above can also be used for radial piston pumps. The roller ring 22 is then replaced by a cam ring which has an articulation pin with an articulation ball. The coupling takes place by engagement of the articulation ball of the articulation pin with a driving bush, which in turn is firmly pressed into a transverse bore of the injection adjuster piston.

Claims

Patentansprüche claims
1 . Kraftstoff-Einspritzpumpe mir einem Gehäuse (10), einer Dosierpumpe (18, 20) und einem Spritzversteller (26) für die Dosierpumpe, wobei der Spritz- versteller einen Kolben (28) aufweist, der von einer Rückstellfeder (48) beaufschlagt wird, dadurch gekennzeichnet, daß zusätzlich eine Startfeder (50) vorgesehen ist, die den Kolben (28) beaufschlagt und entgegen der Rückstellfeder wirkt.1 . Fuel injection pump with a housing (10), a metering pump (18, 20) and a spray adjuster (26) for the metering pump, the spray adjuster having a piston (28) which is acted upon by a return spring (48) characterized in that a starting spring (50) is additionally provided which acts on the piston (28) and acts counter to the return spring.
2. Einspritzpumpe nach Anspruch 1 , dadurch gekennzeichnet, daß die Startfeder (50) im Inneren des Kolbens angeordnet ist.2. Injection pump according to claim 1, characterized in that the starting spring (50) is arranged in the interior of the piston.
3. Einspritzpumpe nach Anspruch 2, dadurch gekennzeichnet, daß die Startfeder (50) sich mit einem Ende am Gehäuse (10) der Einspritzpumpe abstützt.3. Injection pump according to claim 2, characterized in that the starting spring (50) is supported at one end on the housing (10) of the injection pump.
4. Einspritzpumpe nach Anspruch 2, dadurch gekennzeichnet, daß die Startfeder (50) sich mit einem Ende an einem Hilfskolben (52) abstützt, der verschiebbar in einer Aufnahmebohruπg (46) im Kolben (28) gelagert ist und sich am Gehäuse (10) abstützt.4. Injection pump according to claim 2, characterized in that the starting spring (50) is supported at one end on an auxiliary piston (52) which is slidably mounted in a receiving bore (46) in the piston (28) and on the housing (10) supported.
5. Einspritzpumpe nach Anspruch 4, dadurch gekennzeichnet, daß in der Aufnahmebohruπg (46) ein Sicherungsring (54) angeordnet ist, der die Verschiebbarkeit des Hilfskolbens begrenzt. 5. Injection pump according to claim 4, characterized in that a retaining ring (54) is arranged in the receiving bore (46), which limits the displaceability of the auxiliary piston.
EP01905608A 2000-01-12 2001-01-08 Fuel injection pump Withdrawn EP1163439A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10000977 2000-01-12
DE10000977A DE10000977A1 (en) 2000-01-12 2000-01-12 Fuel injection pump
PCT/DE2001/000032 WO2001051803A1 (en) 2000-01-12 2001-01-08 Fuel injection pump

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EP1163439A1 true EP1163439A1 (en) 2001-12-19

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ID=7627281

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EP01905608A Withdrawn EP1163439A1 (en) 2000-01-12 2001-01-08 Fuel injection pump

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US (1) US6488014B2 (en)
EP (1) EP1163439A1 (en)
JP (1) JP2003519755A (en)
DE (1) DE10000977A1 (en)
WO (1) WO2001051803A1 (en)

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Publication number Priority date Publication date Assignee Title
US3486492A (en) * 1967-11-07 1969-12-30 Allis Chalmers Mfg Co Timing advance mechanism
JPS5026911A (en) * 1974-06-27 1975-03-20
DE2644042C2 (en) * 1976-09-30 1986-12-18 Robert Bosch Gmbh, 7000 Stuttgart Adjustment device for the start of injection in a fuel injection pump for an internal combustion engine
DE3121108A1 (en) * 1981-05-27 1982-12-16 Robert Bosch Gmbh, 7000 Stuttgart FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES
JPS58131326A (en) * 1982-02-01 1983-08-05 Japan Electronic Control Syst Co Ltd Injection timing control device for distributed fuel injection pump
DE3345155A1 (en) * 1983-12-14 1985-11-07 Robert Bosch Gmbh, 7000 Stuttgart FUEL INJECTION PUMP
JPS60259731A (en) * 1984-05-08 1985-12-21 Diesel Kiki Co Ltd Injection timing control unit for fuel distribution type injection pump
DE3611044A1 (en) * 1986-04-02 1987-10-08 Bosch Gmbh Robert ADJUSTMENT DEVICE FOR STARTING A SPRAY IN A FUEL INJECTION PUMP
DE4344865A1 (en) 1993-12-29 1995-07-06 Bosch Gmbh Robert Fuel injection pump
JPH0814067A (en) * 1994-06-24 1996-01-16 Zexel Corp Servo valve type timer for fuel injection pump
JPH08261019A (en) * 1995-01-24 1996-10-08 Nippon Soken Inc Injection timing control device for fuel injection pump
JP3572433B2 (en) * 1997-01-31 2004-10-06 日産自動車株式会社 Fuel injection timing control system for diesel engine fuel injection pump

Non-Patent Citations (1)

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Title
See references of WO0151803A1 *

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US6488014B2 (en) 2002-12-03
JP2003519755A (en) 2003-06-24
DE10000977A1 (en) 2001-08-02
US20020104515A1 (en) 2002-08-08
WO2001051803A1 (en) 2001-07-19

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