EP0419612B1 - Fuel injection pump for internal combustion engines - Google Patents

Fuel injection pump for internal combustion engines Download PDF

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Publication number
EP0419612B1
EP0419612B1 EP90904766A EP90904766A EP0419612B1 EP 0419612 B1 EP0419612 B1 EP 0419612B1 EP 90904766 A EP90904766 A EP 90904766A EP 90904766 A EP90904766 A EP 90904766A EP 0419612 B1 EP0419612 B1 EP 0419612B1
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EP
European Patent Office
Prior art keywords
pressure
space
return
fuel injection
internal combustion
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EP90904766A
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German (de)
French (fr)
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EP0419612A1 (en
Inventor
Josef Hain
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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
    • 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
    • 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

Definitions

  • the invention relates to a fuel injection pump according to the preamble of main claims 1, 2.
  • a fuel injection pump is known from DE-OS 31 48 214 and EP-A-250785.
  • the pressure valve provided there in the relief line of the return space can be controlled depending on the temperature in such a way that it is closed when the internal combustion engine is cold started and is open at the latest when the internal combustion engine is warm.
  • the pressure valve is designed as a check valve which can open at a maximum pressure and which is opened by a thermostatically controlled element. As long as the pressure valve is closed, the same pressure, which is determined by the delivery rate of the fuel feed pump, is established in the pressure chamber and in the resetting space, which pressure also acts on the spray adjustment device and adjusts it in the "early" direction.
  • This special early adjustment is canceled at the end of the warm-up phase by opening the pressure valve and then the pressure acting on the spray adjustment device is controlled in a known manner as a function of the speed by the pressure control valve.
  • the special early adjustment improves the cold start behavior and the running of the internal combustion engine in the warm-up phase.
  • the fuel injection pump according to the invention with the characterizing features of the main claims has the advantage that the drain throttle on the pressure control valve is closed quickly and safely during cold start, that the pressure mentioned for the cold start early adjustment can be reached regularly.
  • FIG. 1 shows a first exemplary embodiment of the fuel injection pump according to the invention in a schematic illustration
  • FIG. 2 shows a second exemplary embodiment of the invention
  • FIG Pressure curve in the pressure chamber in front of the pressure control valve or the control pressure effective at the spray adjustment device for various functional positions.
  • a spray adjustment device 2 which has a spray adjustment piston 4 which can be displaced in a cylinder 3 and which is acted upon on one end face by a return spring 5 which is supported in a stationary manner on an end face of the cylinder 3 and on the other end of a spray adjuster working space 6 is limited in the cylinder 3.
  • the injection adjuster working space 6 is connected via a throttle bore 7 in the injection adjustment piston to a suction space 9 in the interior of the fuel injection pump.
  • the suction chamber 9 is supplied with fuel by a feed pump 10, which is driven synchronously with the fuel injection pump 1, via a pressure line 11, the feed pump taking the fuel from a fuel reservoir 13 via a suction line 12.
  • a bypass line 15 is provided in parallel to the feed pump 10, in which a pressure control valve 16 is arranged.
  • This has an adjustable wall in the form of a control piston 17, which slides tightly in a cylinder 18 and delimits on one side a pressure chamber 19 into which the bypass line 15 opens from the pressure line 11.
  • the control piston delimits a return space 20 in which a return spring 22 is arranged, which is supported on the one hand on the control piston 17 and on the other hand is supported on an adjustable stop 23.
  • the reset space 20 is constantly connected to the pressure space 19 via a throttle 24.
  • the reset space 20 is connected to the pressure space via a relief line 26 27 of a pressure valve 28, which is designed as a pressure control valve in the form of a check valve, the valve closing member 29 of which can be pushed open by a temperature-dependent actuator 30.
  • This actuator is, for example, a thermostat or an expansion element, which is exposed to the cooling water of the internal combustion engine and thus detects the operating temperature of the internal combustion engine. Accordingly, the closing element 29 is pushed open by the actuator when the internal combustion engine is at operating temperature, and thus the relief line 26 is connected to a relief line part 26 leading further to the fuel supply 13 downstream of the valve closing element 29.
  • a second pressure valve 33 is connected in parallel to the pressure valve 28 and lies in a bypass line 34 to the pressure valve 28.
  • the second pressure valve 33 has a piston 37 which is tightly displaceable in a cylinder 36 and which delimits a pressure chamber 38 on the one side and a relieved space 39 on the other side, in which a return spring 40 which loads the piston 37 is arranged by means of an adjusting member 41 is adjustable.
  • the pressure chamber 38 is constantly connected to the delivery side of the feed pump 10 and thus has the same pressure that prevails in the suction chamber 9 or in the pressure chamber 19.
  • This pressure allows the piston 37 to be displaced against the return spring and, in the course of the displacement, comes with an annular groove 43 provided on the circumference of the piston in connection with an inlet opening 44 of the bypass line 34 in the cylinder wall of the cylinder 36. Because the annular groove 43 has a longitudinal bore 45 is permanently connected to the relieved space 39, at this moment the bypass line 34 is connected to the continuing part of the relief line 26 via the relieved space 39 and via a part of the bypass line 34 extending therefrom. At this moment, the pressure valve 28 is bypassed, so that the reset space 20 of the pressure control valve 16 is relieved, even when the pressure control valve 28 is closed.
  • the connection is established as a function of the pressure in the pressure chamber 38, which can be set with the aid of the setting member 41 or the return spring 40.
  • the pressure in the pressure chamber 38 is always the same as in the pressure chamber 19 of the pressure control valve, which ultimately controls this pressure in conjunction with the delivery rate of delivery pump 10, which is driven synchronously with the speed of the fuel injection pump.
  • the pressure control valve in the radial wall of the cylinder 18 has a discharge throttle 46 which is connected via a bypass line 15 to the suction line 12 of the feed pump 10 or via this to the relief chamber in the form of the fuel supply 13.
  • the cross section of the discharge throttle is determined by the Position of the control piston 17 determined and controlled by its front edge.
  • the position of the control piston is in turn determined by the pressure in the pressure chamber 19 and the force acting on it from the restoring chamber 20. This is essentially determined by return spring 22, the pretension of which is in turn determined by the adjustable stop 23.
  • This has the shape of a stepped piston, the part 49 of which has a smaller diameter at the end of the reset space 20 and whose larger part 50 includes a working space 51 which is connected via a line 52 to the relief line 26 or to the reset space 20.
  • the interior of the fuel injection pump is filled with fuel.
  • the feed pump 10 is set in motion and generates a pressure in the suction chamber 9 or pressure chamber 19 of the pressure control valve 16.
  • This pressure propagates through the throttle 24 into the reset chamber 20 and from there via the line 52 into the working chamber 51.
  • This pressure quickly causes a displacement of the adjustable stop in the direction of the control piston 17, so that it is moved so that the discharge throttle 46 is initially securely closed.
  • the relief line 26 is closed by the pressure valve 28 and the bypass line 34 is also closed by the second pressure valve 33.
  • an effective control pressure which could now be controlled via the pressure control valve 16, can build up very quickly in the interior of the fuel injection pump.
  • the pressure valve 28 When the internal combustion engine is at operating temperature, the pressure valve 28 is open from the start via the actuator 30, the adjustable stop 23 in its normal position relieving the return spring 22 and the pressure control valve 16 in the normal function. Accordingly, there is a profile of the pressure in the suction chamber 9 as a function of the speed according to the approximately linearly increasing characteristic curve 64 in FIG. 3. Without the measure according to the invention, a pressure curve according to characteristic curve 65 with little pronounced steepness at the start of the speed would result for the cold start.
  • FIG. 2 shows a variant of the embodiment according to FIG. 1.
  • the work space 51 is connected to the pressure space 19 via a separate line 54 in which a throttle 55 is arranged.
  • the pressure chamber 51 is also connected via a controllable pressure-maintaining valve 56 to the suction line 12 of the feed pump 10 or to the relief chamber 13.
  • the throttle 55 takes over the decoupling function that the throttle 24 from FIG. 1 had as a connecting element to the working chamber 51.
  • the controllable pressure-maintaining valve 56 functions in place of the pressure valve 28 or the second pressure valve 33. With the controllable pressure valve, the pressure in the working space 51 can now be controlled more precisely and taking into account specific parameters.
  • the temperature is also the main parameter for this pressure control valve.

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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)
  • High-Pressure Fuel Injection Pump Control (AREA)

Abstract

To ensure a very rapid increase in pressure inside a fuel injection pump for internal combustion engines, a pressure-control valve which controls this pressure is modified so that it is closed from the beginning when the internal combustion engine is started from the cold. To this end, the rear face of a control piston (17) of the pressure control valve (16) is acted on by a restoring spring (22) whose other point of support is an adjustable limit stop (23) which is acted on by the increasing pressure in the fuel injection pump, thereby preloading the restoring spring (22). This causes an outlet choke (46) controlled by the control piston (17) to close, so that all the fuel delivered by a feed pump (10) remains inside the pump chamber and contributes to the increase in pressure. This pressure results in very rapid adjustment of an injection adjustment piston (4), ensuring an early start of fuel injection which facilitates cold start and warm up.

Description

Stand der TechnikState of the art

Die Erfindung geht aus von einer Kraftstoffeinspritzpumpe nach der Gattung der Hauptansprüche 1, 2. Eine solche ist aus DE-OS 31 48 214 und EP-A-250785 bekannt. Das dort in der Entlastungsleitung des Rückstellraums vorgesehene Druckventil ist temperaturabhängig steuerbar derart, daß es beim Kaltstart der Brennkraftmaschine geschlossen ist und bei betriebswarmer Brennkraftmaschine spätestens geöffnet ist. Dabei ist das Druckventil als Rückschlagventil ausgebildet, das bei einem Höchstdruck öffnen kann und das durch ein thermostatisch gesteuertes Element aufgestoßen wird. Solange das Druckventil geschlossen ist, stellt sich im Druckraum und im Rückstellraum derselbe, durch die Förderrate der Kraftstofförderpumpe bestimmte Druck ein, der auch an der Spritzverstellvorrichtung wirksam wird und diese in Richtung "früh" verstellt. Diese spezielle Frühverstellung wird am Ende der Warmlaufphase durch Aufsteuern des Druckventils aufgehoben und danach der auf die Spritzverstellvorrichtung wirkende Druck in bekannter Weise drehzahlabhängig durch das Drucksteuerventil gesteuert. Die spezielle Frühverstellung bewirkt eine Verbesserung des Kaltstartverhaltens und des Laufes der Brennkraftmaschine in der Aufwärmphase.The invention relates to a fuel injection pump according to the preamble of main claims 1, 2. Such a pump is known from DE-OS 31 48 214 and EP-A-250785. The pressure valve provided there in the relief line of the return space can be controlled depending on the temperature in such a way that it is closed when the internal combustion engine is cold started and is open at the latest when the internal combustion engine is warm. The pressure valve is designed as a check valve which can open at a maximum pressure and which is opened by a thermostatically controlled element. As long as the pressure valve is closed, the same pressure, which is determined by the delivery rate of the fuel feed pump, is established in the pressure chamber and in the resetting space, which pressure also acts on the spray adjustment device and adjusts it in the "early" direction. This special early adjustment is canceled at the end of the warm-up phase by opening the pressure valve and then the pressure acting on the spray adjustment device is controlled in a known manner as a function of the speed by the pressure control valve. The special early adjustment improves the cold start behavior and the running of the internal combustion engine in the warm-up phase.

Nachteilig ist es bei der bekannten Einrichtung, daß am Drucksteuerventil beim Stillstand der Kraftstoffeinspritzpumpe ein kleiner Restspalt der Abflußdrossel vom Druckraum zum Entlastungsraum offen bleibt und beim Anlauf der Kraftstoffeinspritzpumpe der Förderpumpenliefergrad dann nicht ausreicht, den erforderlichen Druck bei niedrigen Drehzahlen in der Ablaufphase der Brennkraftmaschine bzw. der Kraftstoffeinspritzpumpe im Druckraum bzw. im Rückstellraum sofort zu erzeugen derart, daß zugleich die besondere Frühverstellung für den Kaltstart erzielt wird. Erst mit zunehmender Drehzahl und Liefermenge der Förderpumpe stellt sich dann verzögert der gewünschte Druck ein.It is a disadvantage of the known device that on the pressure control valve when the fuel injection pump is at a standstill, a small remaining gap of the discharge throttle from the pressure chamber to the relief chamber remains open and when the fuel injection pump starts, the delivery pump delivery rate is then insufficient, the required pressure at low speeds in the running phase of the internal combustion engine or to generate the fuel injection pump in the pressure chamber or in the recovery room immediately in such a way that the special early adjustment for the cold start is achieved at the same time. It is only with increasing speed and delivery quantity of the feed pump that the desired pressure is delayed.

Vorteile der ErfindungAdvantages of the invention

Die erfindungsgemäße Kraftstoffeinspritzpumpe mit den kennzeichnenden Merkmalen der Hauptansprüche hat demgegenüber den Vorteil, daß die Abflußdrossel am Drucksteuerventil beim Kaltstart sogleich schnell und sicher geschlossen ist, daß der eingangs genannte Druck für die Kaltstartfrühverstellung regelmäßig erreichbar ist.The fuel injection pump according to the invention with the characterizing features of the main claims has the advantage that the drain throttle on the pressure control valve is closed quickly and safely during cold start, that the pressure mentioned for the cold start early adjustment can be reached regularly.

Durch die in den Unteransprüchen aufgeführten Maßnahmen sind vorteilhafte Weiterbildungen und Verbesserungen der in den Hauptansprüchen angegebenen Kraftstoffeinspritzpumpe möglich.The measures listed in the subclaims permit advantageous developments and improvements of the fuel injection pump specified in the main claims.

Zeichnungdrawing

Zwei Ausführungsbeispiele der Erfindung sind in der Zeichnung vereinfacht dargestellt und im folgenden näher beschrieben.Two embodiments of the invention are shown in simplified form in the drawing and described in more detail below.

Es zeigen Figur 1 ein erstes Ausführungsbeispiel der erfindungsgemäßen Kraftstoffeinspritzpumpe in schematischer Darstellung, Figur 2 ein zweites Ausführungsbeispiel der Erfindung und Figur 3 den Druckverlauf im Druckraum vor dem Drucksteuerventil bzw. des an der Spritzverstellvorrichtung wirksamen Steuerdrucks bei verschiedenen Funktionslagen.1 shows a first exemplary embodiment of the fuel injection pump according to the invention in a schematic illustration, FIG. 2 shows a second exemplary embodiment of the invention and FIG Pressure curve in the pressure chamber in front of the pressure control valve or the control pressure effective at the spray adjustment device for various functional positions.

Beschreibung der AusführungsbeispieleDescription of the embodiments

In Figur 1 ist lediglich ein Teil einer Verteilerkraftstoffeinspritzpumpe 1 dargestellt mit einer Spritzverstellvorrichtung 2, die einen in einem Zylinder 3 verschiebbaren Spritzverstellkolben 4 aufweist, der auf seiner einen Stirnseite von einer Rückstellfeder 5 beaufschlagt ist, die sich ortsfest an einer Stirnseite des Zylinders 3 abstützt und auf dessen anderer Stirnseite ein Spritzverstellerarbeitsraum 6 im Zylinder 3 begrenzt wird. Der Spritzverstellerarbeitsraum 6 ist über eine Drosselbohrung 7 im Spritzverstellkolben mit einem Saugraum 9 im Innern der Kraftstoffeinspritzpumpe verbunden. Der Saugraum 9 wird von einer synchron zur Kraftstoffeinspritzpumpe 1 angetriebenen Förderpumpe 10 über eine Druckleitung 11 mit Kraftstoff versorgt, wobei die Förderpumpe über eine Saugleitung 12 den Kraftstoff aus einem Kraftstoffvorratsbehälter 13 entnimmt.In Figure 1, only a part of a distributor fuel injection pump 1 is shown with a spray adjustment device 2, which has a spray adjustment piston 4 which can be displaced in a cylinder 3 and which is acted upon on one end face by a return spring 5 which is supported in a stationary manner on an end face of the cylinder 3 and on the other end of a spray adjuster working space 6 is limited in the cylinder 3. The injection adjuster working space 6 is connected via a throttle bore 7 in the injection adjustment piston to a suction space 9 in the interior of the fuel injection pump. The suction chamber 9 is supplied with fuel by a feed pump 10, which is driven synchronously with the fuel injection pump 1, via a pressure line 11, the feed pump taking the fuel from a fuel reservoir 13 via a suction line 12.

Parallel zur Förderpumpe 10 ist eine Bypassleitung 15 vorgesehen, in der ein Drucksteuerventil 16 angeordnet ist. Dieses weist eine verstellbare Wand in Form eines Steuerkolbens 17, der in einem Zylinder 18 dicht gleitet und auf der einen Seite einen Druckraum 19 begrenzt, in den die Bypassleitung 15 von der Druckleitung 11 einmündet. Auf der anderen Seite begrenzt der Steuerkolben einen Rückstellraum 20, in dem eine Rückstellfeder 22 angeordnet ist, die sich einerseits am Steuerkolben 17 abstützt und andererseits an einem verstellbaren Anschlag 23 abstützt. Der Rückstellraum 20 ist mit dem Druckraum 19 ständig über eine Drossel 24 verbunden. Weiterhin ist der Rückstellraum 20 über eine Entlastungsleitung 26 mit dem Druckraum 27 eines Druckventils 28 verbunden, das als Druckhalteventil in Form eines Rückschlagventils ausgebildet ist, dessen Ventilschließglied 29 durch ein temperturabhängig betätigtes Stellglied 30 aufgestoßen werden kann. Dieses Stellglied ist zum Beispiel ein Thermostat oder ein Dehnstoffelement, das dem Kühlwasser der Brennkraftmaschine ausgesetzt ist und somit die Betriebstemperatur der Brennkraftmaschine erfaßt. Dementsprechend wird durch das Stellglied bei betriebswarmer Brennkraftmaschine das Schließglied 29 aufgestoßen und somit die Entlastungsleitung 26 mit einem stromabwärts des Ventilschließglieds 29 weiter zum Kraftstoffvorrat 13 führenden Entlastungsleitungsteil 26 verbunden.A bypass line 15 is provided in parallel to the feed pump 10, in which a pressure control valve 16 is arranged. This has an adjustable wall in the form of a control piston 17, which slides tightly in a cylinder 18 and delimits on one side a pressure chamber 19 into which the bypass line 15 opens from the pressure line 11. On the other hand, the control piston delimits a return space 20 in which a return spring 22 is arranged, which is supported on the one hand on the control piston 17 and on the other hand is supported on an adjustable stop 23. The reset space 20 is constantly connected to the pressure space 19 via a throttle 24. Furthermore, the reset space 20 is connected to the pressure space via a relief line 26 27 of a pressure valve 28, which is designed as a pressure control valve in the form of a check valve, the valve closing member 29 of which can be pushed open by a temperature-dependent actuator 30. This actuator is, for example, a thermostat or an expansion element, which is exposed to the cooling water of the internal combustion engine and thus detects the operating temperature of the internal combustion engine. Accordingly, the closing element 29 is pushed open by the actuator when the internal combustion engine is at operating temperature, and thus the relief line 26 is connected to a relief line part 26 leading further to the fuel supply 13 downstream of the valve closing element 29.

Parallel zum Druckventil 28 ist ein zweites Druckventil 33 geschaltet, das in einer Bypassleitung 34 zum Druckventil 28 liegt. Das zweite Druckventil 33 weist dabei einen in einem Zylinder 36 dicht verschiebbaren Kolben 37 auf, der auf der einen Seite einen Druckraum 38 und auf der anderen Seite einen entlasteten Raum 39 begrenzt, in dem eine den Kolben 37 belastende Rückstellfeder 40 angeordnet ist, die mittels eines Einstellglieds 41 einstellbar ist. Der Druckraum 38 ist ständig mit der Förderseite der Förderpumpe 10 verbunden und weist somit denselben Druck auf, der im Saugraum 9 bzw. im Druckraum 19 herrscht. Durch diesen Druck ist der Kolben 37 gegen die Rückstellfeder verschiebbar und kommt im Laufe der Verschiebung mit einer am Umfang des Kolbens vorgesehenen Ringnut 43 in Verbindung mit einer Eintrittsöffnung 44 der Bypassleitung 34 in der Zylinderwand des Zylinders 36. Da die Ringnut 43 über eine Längsbohrung 45 ständig mit dem entlasteten Raum 39 verbunden ist, so wird in diesem Moment die Bypassleitung 34 über den entlasteten Raum 39 und über ein von diesem weiterführenden Teil der Bypassleitung 34 mit dem weiterführenden Teil der Entlastungsleitung 26 verbunden. In diesem Moment ist das Druckventil 28 umgangen, so daß der Rückstellraum 20 des Drucksteuerventils 16 entlastet wird, auch dann wenn das Drucksteuerventil 28 geschlossen ist.A second pressure valve 33 is connected in parallel to the pressure valve 28 and lies in a bypass line 34 to the pressure valve 28. The second pressure valve 33 has a piston 37 which is tightly displaceable in a cylinder 36 and which delimits a pressure chamber 38 on the one side and a relieved space 39 on the other side, in which a return spring 40 which loads the piston 37 is arranged by means of an adjusting member 41 is adjustable. The pressure chamber 38 is constantly connected to the delivery side of the feed pump 10 and thus has the same pressure that prevails in the suction chamber 9 or in the pressure chamber 19. This pressure allows the piston 37 to be displaced against the return spring and, in the course of the displacement, comes with an annular groove 43 provided on the circumference of the piston in connection with an inlet opening 44 of the bypass line 34 in the cylinder wall of the cylinder 36. Because the annular groove 43 has a longitudinal bore 45 is permanently connected to the relieved space 39, at this moment the bypass line 34 is connected to the continuing part of the relief line 26 via the relieved space 39 and via a part of the bypass line 34 extending therefrom. At this moment, the pressure valve 28 is bypassed, so that the reset space 20 of the pressure control valve 16 is relieved, even when the pressure control valve 28 is closed.

Das Herstellen der Verbindung erfolgt in Abhängigkeit vom Druck im Druckraum 38, der mit Hilfe des Einstellglieds 41 bzw. der Rückstellfeder 40 einstellbar ist. Der Druck im Druckraum 38 ist immer derselbe wie im Druckraum 19 des Drucksteuerventils, das letztendlich diesen Druck in Verbindung mit dem Förderlieferungsgrad der synchron zur Drehzahl der Kraftstoffeinspritzpumpe angetriebenen Förderpumpe 10 steuert. Dazu weist das Drucksteuerventil in der radialen Wand des Zylinders 18 eine Abflußdrossel 46 auf, die über eine Bypassleitung 15 mit der Saugleitung 12 der Förderpumpe 10 verbunden ist bzw. über diese mit dem Entlastungsraum in Form des Kraftstoffvorrats 13. Der Querschnitt der Abflußdrossel wird durch die Stellung des Steuerkolbens 17 bestimmt und durch dessen stirnseitige Kante gesteuert. Die Stellung des Steuerkolbens wiederum wird durch den Druck im Druckraum 19 bestimmt und der vom Rückstellraum 20 her auf diesen wirkenden Kraft. Diese wird wesentlich durch Rückstellfeder 22 bestimmt, deren Vorspannung wiederum durch den verstellbaren Anschlag 23 bestimmt ist. Dieser weist die Form eines Stufenkolbens auf, dessen im Durchmesser kleinerer Teil 49 stirnseitig den Rückstellraum 20 begrenzt und dessen im Durchmesser größerer Teil 50 einen Arbeitsraum 51 einschließt, der über eine Leitung 52 mit der Entlastungsleitung 26 bzw. mit dem Rückstellraum 20 verbunden ist.The connection is established as a function of the pressure in the pressure chamber 38, which can be set with the aid of the setting member 41 or the return spring 40. The pressure in the pressure chamber 38 is always the same as in the pressure chamber 19 of the pressure control valve, which ultimately controls this pressure in conjunction with the delivery rate of delivery pump 10, which is driven synchronously with the speed of the fuel injection pump. For this purpose, the pressure control valve in the radial wall of the cylinder 18 has a discharge throttle 46 which is connected via a bypass line 15 to the suction line 12 of the feed pump 10 or via this to the relief chamber in the form of the fuel supply 13. The cross section of the discharge throttle is determined by the Position of the control piston 17 determined and controlled by its front edge. The position of the control piston is in turn determined by the pressure in the pressure chamber 19 and the force acting on it from the restoring chamber 20. This is essentially determined by return spring 22, the pretension of which is in turn determined by the adjustable stop 23. This has the shape of a stepped piston, the part 49 of which has a smaller diameter at the end of the reset space 20 and whose larger part 50 includes a working space 51 which is connected via a line 52 to the relief line 26 or to the reset space 20.

Im Betrieb der Kraftstoffeinspritzpumpe ist der Innenraum der Kraftstoffeinspritzpumpe mit Kraftstoff gefüllt. Beim Start wird die Förderpumpe 10 in Bewegung gesetzt und erzeugt einen Druck im Saugraum 9 bzw. Druckraum 19 des Drucksteuerventils 16. Dieser Druck pflanzt sich über die Drossel 24 fort in den Rückstellraum 20 und von dort über die Leitung 52 auch in den Arbeitsraum 51. Dieser Druck bewirkt schnell eine Verschiebung des verstellbaren Anschlags in Richtung Steuerkolben 17, so daß dieser so verschoben wird, daß zunächst die Abflußdrossel 46 sicher verschlossen ist. Dies unter der Voraussetzung, daß gemäß dem angenommenen Fall eines Kaltstarts die Entlastungsleitung 26 durch das Druckventil 28 geschlossen ist und auch die Bypassleitung 34 durch das zweite Druckventil 33 geschlossen ist. In der Folge kann sich im Innern der Kraftstoffeinspritzpumpe sehr schnell ein wirksamer Steuerdruck aufbauen, der nun über das Drucksteuerventil 16 gesteuert werden könnte. Wegen des vorhandenen Druckausgleichs zwischen Rückstellraum 20 und Druckraum 19 bleibt jedoch die Abflußdrossel 46 weiterhin geschlossen, so daß der Druck im Saugraum 9 schnell ansteigt. Dies ist der Kennlinie 60 in Figur 3 zu entnehmen. Nach einem steil ansteigenden Ast 62 wird dann jedoch im Punkt 63 ein Druck erreicht, bei dem das zweite Druckventil 33 öffnet und somit die Steuerdruckhöhe auf einen bestimmten Wert begrenzt wird. Entsprechend früh wird der Spritzverstellerkolben 4 entgegen der Feder 5 verschoben. Bei weiterem Drehzahlanstieg ergibt sich ein mit der Drehzahl zunehmender Verlauf des Steuerdrucks, da nun der Rückstellraum 20 des Drucksteuerventils 16 über das zweite Druckventil entlastet ist und das Drucksteuerventil nun drehzahlabhängig ab diesem Einsatzdruck den Druck im Saugraum 9 steuert durch mehr oder weniger Öffnen der Abflußdrossel 46. Auch der Arbeitsraum 51 ist durch Öffnen des zweiten Druckventils 33 entlastet, so daß der verstellbare Anschlag 23 in seine Normallage zurückgeht und das Drucksteuerventil 16 in gewünschter genauer Weise dem drehzahlabhängigen Druck im Saugraum 9 steuert. Es wurde somit erreicht, daß mit Hilfe des verstellbaren Anschlags 23 und dem verringerten Weg der Rückstellfeder 22 in bezug auf die Lage der Abflußdrossel 46 ein sicheres Schließen derselben erzielt wird, was den schnellen Druckaufbau bewirkt und einen schnellen Einsatz der Kaltstartfrühverstellung gewährleistet. Bei betriebswarmer Brennkraftmaschine ist das Druckventil 28 über das Stellglied 30 von anfang an geöffnet, der verstellbare Anschlag 23 in seiner die Rückstellfeder 22 entlastenden Normalstellung und das Drucksteuerventil 16 in Normalfunktion. Dementsprechend ergibt sich ein Verlauf des Drucks im Saugraum 9 in Abhängigkeit von der Drehzahl gemäß der etwa linear ansteigenden Kennlinie 64 in Figur 3. Ohne die erfindungsgemäße Maßnahme ergäbe sich für den Kaltstart ein Druckverlauf gemäß der Kennlinie 65 mit wenig ausgeprägter Steilheit bei Drehzahlbeginn.When the fuel injection pump is in operation, the interior of the fuel injection pump is filled with fuel. At the start, the feed pump 10 is set in motion and generates a pressure in the suction chamber 9 or pressure chamber 19 of the pressure control valve 16. This pressure propagates through the throttle 24 into the reset chamber 20 and from there via the line 52 into the working chamber 51. This pressure quickly causes a displacement of the adjustable stop in the direction of the control piston 17, so that it is moved so that the discharge throttle 46 is initially securely closed. This provided that, according to the assumed case of a cold start the relief line 26 is closed by the pressure valve 28 and the bypass line 34 is also closed by the second pressure valve 33. As a result, an effective control pressure, which could now be controlled via the pressure control valve 16, can build up very quickly in the interior of the fuel injection pump. Because of the existing pressure equalization between the recovery chamber 20 and the pressure chamber 19, however, the discharge throttle 46 remains closed, so that the pressure in the suction chamber 9 rises quickly. This can be seen from the characteristic curve 60 in FIG. 3. After a steeply rising branch 62, however, a pressure is then reached at point 63 at which the second pressure valve 33 opens and the control pressure level is thus limited to a certain value. The injection adjuster piston 4 is displaced accordingly early against the spring 5. With a further increase in speed, the course of the control pressure increases with the speed, since the return space 20 of the pressure control valve 16 is now relieved via the second pressure valve and the pressure control valve now controls the pressure in the suction space 9 as a function of the speed from this operating pressure by opening the discharge throttle 46 more or less The work chamber 51 is also relieved by opening the second pressure valve 33, so that the adjustable stop 23 returns to its normal position and the pressure control valve 16 controls the speed-dependent pressure in the suction chamber 9 in the desired precise manner. It was thus achieved that with the help of the adjustable stop 23 and the reduced path of the return spring 22 with respect to the position of the discharge throttle 46, a safe closing of the same is achieved, which causes the rapid pressure build-up and ensures a quick use of the cold start early adjustment. When the internal combustion engine is at operating temperature, the pressure valve 28 is open from the start via the actuator 30, the adjustable stop 23 in its normal position relieving the return spring 22 and the pressure control valve 16 in the normal function. Accordingly, there is a profile of the pressure in the suction chamber 9 as a function of the speed according to the approximately linearly increasing characteristic curve 64 in FIG. 3. Without the measure according to the invention, a pressure curve according to characteristic curve 65 with little pronounced steepness at the start of the speed would result for the cold start.

In Figur 2 ist eine Variante zur Ausführung nach Figur 1 dargestellt. In diesem Falle ist der Arbeitsraum 51 über eine separate Leitung 54, in der eine Drossel 55 angeordnet ist, mit dem Druckraum 19 verbunden. Der Druckraum 51 ist ferner über ein steuerbares Druckhalteventil 56 mit der Saugleitung 12 der Förderpumpe 10 verbunden bzw. mit dem Entlastungsraum 13. In diesem Falle übernimmt die Drossel 55 die abkoppelnde Funktion, die die Drossel 24 von Figur 1 als Verbindungselement zum Arbeitsraum 51 hatte. Ferner tritt das steuerbare Druckhalteventil 56 funktionsmäßig an die Stelle des Druckventils 28 bzw. des zweiten Druckventils 33. Mit dem steuerbaren Druckventil kann nun genauer und unter Berücksichtigung spezifischer Parameter der Druck im Arbeitsraum 51 gesteuert werden. Auch für dieses Druckhalteventil kommt als Hauptparameter die Temperatur in Frage.FIG. 2 shows a variant of the embodiment according to FIG. 1. In this case, the work space 51 is connected to the pressure space 19 via a separate line 54 in which a throttle 55 is arranged. The pressure chamber 51 is also connected via a controllable pressure-maintaining valve 56 to the suction line 12 of the feed pump 10 or to the relief chamber 13. In this case, the throttle 55 takes over the decoupling function that the throttle 24 from FIG. 1 had as a connecting element to the working chamber 51. Furthermore, the controllable pressure-maintaining valve 56 functions in place of the pressure valve 28 or the second pressure valve 33. With the controllable pressure valve, the pressure in the working space 51 can now be controlled more precisely and taking into account specific parameters. The temperature is also the main parameter for this pressure control valve.

Claims (4)

  1. Fuel injection pump for internal combustion engines, in particular distributor injection pumps, having a beginning of injection adjustment device (2), which has as a setting element a first wall (4) which can be adjusted against a return force (5) by a pressure medium control pressure which depends on rotational speed, having a feed pump (10) driven synchronously with the fuel injection pump, the delivery pressure of which feed pump (10) acts as a control pressure and is controlled by a pressure control valve (16) which has a second wall (17), which is acted on by the control pressure and can be adjusted against a return spring (22), which wall (17) separates a pressure space (19) from a return space (20) accommodating the return spring (22), which return space (20) is continuously connected to the pressure space (19) via a throttle (24), an outlet throttle (46) from the pressure space (19) to a relief space (13) being controlled by the setting motion of the adjustable second wall (17), and the return space (20) being connected to the relief space (13) via a relief conduit which contains a pressure retention valve (28), which can be controlled as a function of temperature and is opened when the internal combustion engine is at operating temperature, characterized in that the return spring (22) of the pressure control valve (16) is supported on an adjustable stop (23), which has, on its end facing away from the return space (20), a pressure surface which is larger relative to the end facing towards the return space, which pressure surface bounds a working space (51) which can be connected to the relief space (13) via the controllable pressure retention valve (28) and is connected to the pressure space (19) of the pressure control valve (16) via the throttle (24).
  2. Fuel injection pump for internal combustion engines, in particular distributor injection pumps, having a beginning of injection adjustment device (2), which has as a setting element a first wall (4) which can be adjusted against a return force (5) by a pressure medium control pressure which depends on rotational speed, having a feed pump (10) driven synchronously with the fuel injection pump, the delivery pressure of which feed pump (10) acts as a control pressure and is controlled by a pressure control valve (16) which has a second wall (17), which is acted on by the control pressure and can be adjusted against a return spring (22), which wall (17) separates a pressure space (19) from a return space (20) accommodating the return spring (22), which return space (20) is continuously connected to the pressure space (19) via a throttle (24), an outlet throttle (46) from the pressure space (19) to a relief space (13) being controlled by the setting motion of the adjustable second wall (17), and the return space (20) being connected to the relief space (13) via a relief conduit which contains a first pressure retention valve (28), which can be controlled as a function of temperature and is opened when the internal combustion engine is at operating temperature, characterized in that the return spring (22) of the pressure control valve (16) is supported on an adjustable stop (23), which has, on its end facing away from the return space (20), a pressure surface which is larger relative to the end facing towards the return space, which pressure surface bounds a working space (51) which can be connected to the relief space (13) via a controllable second pressure retention valve (56) and is connected to the pressure space (19) of the pressure control valve (16) via a second throttle (55).
  3. Fuel injection pump for internal combustion engines according to Claim 2, characterized in that the second throttle (55) is located in a conduit (54) between the pressure space (19) and the working space (51).
  4. Fuel injection pump according to Claim 3, characterized in that the retention pressure of the controllable second pressure retention valve (56) can be controlled as a function of the temperature.
EP90904766A 1989-04-18 1990-03-23 Fuel injection pump for internal combustion engines Expired - Lifetime EP0419612B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE3912624 1989-04-18
DE3912624A DE3912624A1 (en) 1989-04-18 1989-04-18 FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES
PCT/DE1990/000235 WO1990012957A1 (en) 1989-04-18 1990-03-23 Fuel injection pump for internal combustion engines

Publications (2)

Publication Number Publication Date
EP0419612A1 EP0419612A1 (en) 1991-04-03
EP0419612B1 true EP0419612B1 (en) 1994-08-03

Family

ID=6378874

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Application Number Title Priority Date Filing Date
EP90904766A Expired - Lifetime EP0419612B1 (en) 1989-04-18 1990-03-23 Fuel injection pump for internal combustion engines

Country Status (5)

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US (1) US5085196A (en)
EP (1) EP0419612B1 (en)
JP (1) JP2895218B2 (en)
DE (2) DE3912624A1 (en)
WO (1) WO1990012957A1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4117813A1 (en) * 1991-05-31 1992-12-03 Bosch Gmbh Robert FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES
EP0635100A1 (en) * 1992-04-09 1995-01-25 Lucas Industries Public Limited Company Fuel pumping apparatus
DE19832842C1 (en) * 1998-07-21 2000-02-17 Bosch Gmbh Robert Fuel delivery system for supplying fuel to an internal combustion engine

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1932600C3 (en) * 1969-06-27 1978-07-27 Robert Bosch Gmbh, 7000 Stuttgart Fuel injection system for compression ignition engines with a change in the start of injection
DE2854422A1 (en) * 1978-12-16 1980-07-03 Bosch Gmbh Robert FUEL INJECTION SYSTEM FOR DIESEL INTERNAL COMBUSTION ENGINES, ESPECIALLY FOR VEHICLE DIESEL ENGINES
DE2925418A1 (en) * 1979-06-23 1981-01-29 Bosch Gmbh Robert FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES
DE2931938A1 (en) * 1979-08-07 1981-02-26 Bosch Gmbh Robert FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES
DE2931937A1 (en) * 1979-08-07 1981-02-26 Bosch Gmbh Robert FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES
DE3037730A1 (en) * 1980-10-06 1982-05-19 Robert Bosch Gmbh, 7000 Stuttgart FUEL INJECTION SYSTEM FOR INTERNAL COMBUSTION ENGINES
DE3138606A1 (en) * 1981-09-29 1983-04-14 Robert Bosch Gmbh, 7000 Stuttgart FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES
DE3138607A1 (en) * 1981-09-29 1983-04-14 Robert Bosch Gmbh, 7000 Stuttgart FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES
DE3211877A1 (en) * 1982-03-31 1983-10-06 Bosch Gmbh Robert FUEL INJECTION PUMP
DE3410146A1 (en) * 1984-03-20 1985-10-03 Robert Bosch Gmbh, 7000 Stuttgart FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES
DE3517974A1 (en) * 1985-05-18 1986-11-20 Robert Bosch Gmbh, 7000 Stuttgart FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES
GB2178559A (en) * 1985-07-26 1987-02-11 Perkins Engines Group Fuel injection pump
DE3619325A1 (en) * 1986-06-09 1987-12-10 Bosch Gmbh Robert FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES
DE3822257A1 (en) * 1988-07-01 1990-01-04 Bosch Gmbh Robert FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES

Also Published As

Publication number Publication date
WO1990012957A1 (en) 1990-11-01
JP2895218B2 (en) 1999-05-24
US5085196A (en) 1992-02-04
DE3912624A1 (en) 1990-10-25
DE59006681D1 (en) 1994-09-08
JPH03505477A (en) 1991-11-28
EP0419612A1 (en) 1991-04-03

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