EP0515813B1 - Fuel injection pump for internal combustion engines - Google Patents

Fuel injection pump for internal combustion engines Download PDF

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Publication number
EP0515813B1
EP0515813B1 EP92106301A EP92106301A EP0515813B1 EP 0515813 B1 EP0515813 B1 EP 0515813B1 EP 92106301 A EP92106301 A EP 92106301A EP 92106301 A EP92106301 A EP 92106301A EP 0515813 B1 EP0515813 B1 EP 0515813B1
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EP
European Patent Office
Prior art keywords
pressure
space
control
control valve
restoring
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP92106301A
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German (de)
French (fr)
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EP0515813A1 (en
Inventor
Karl Konrath
Hannes Dipl.-Min. Pflug
Paul Wuetherich
Helmut Simon
Mohammad-Ali Dr.-Ing. Khosrawi
Berni Dipl.-Ing. Reisser
Christian Dipl.-Ing. Taudt
Wolfgang Goll
Michael Dipl.-Ing. Scharf
Thomas Dipl.-Wirt.-Ing. Fortenbacher (Fh)
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Robert Bosch GmbH
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Robert Bosch GmbH
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Publication of EP0515813A1 publication Critical patent/EP0515813A1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • 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
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/06—Fuel or fuel supply system parameters
    • F02D2200/0606—Fuel temperature

Definitions

  • the invention is based on a fuel injection pump according to the preamble of the main claim.
  • a fuel injection pump according to the preamble of the main claim.
  • Such is known from German patent application DE-A-39 12 624.
  • a hydraulic blocking of the pressure control valve of the feed pump prevents it from being deactivated and thus the entire fuel delivered is used to build up the control pressure. In this way, even with a cold internal combustion engine, a high suction chamber pressure and the associated spray adjustment in the direction of early can be achieved as quickly as possible.
  • the known cold start system consists of a fuel injection pump with an injection adjustment device, a feed pump via which a pressure control valve located in the feed line to the fuel injection pump controls the inflow to the suction space and two valves arranged in parallel in the relief line of the pressure control valve return space, one of which depends on the operating temperature of the engine and the other is opened depending on the control pressure in the suction chamber.
  • These two valves in the relief line of the pressure control reset chamber enable the fuel flow to be shut off in the warm-up phase or when the engine is started by hydraulically blocking the bypass line via the pressure control valve, so that all of the fuel flows to the fuel injection pump and can build up the control pressure quickly in a known manner , which results in an advance adjustment of the spray adjustment device.
  • the fuel injection pump according to the invention with the features of claim 1 has the advantage that the position of the actuating piston of the spray adjustment device is used as a speed-proportional signal to control the blocking of the relief line of the pressure control valve. This eliminates a separate pressure-controlled valve, which represents a noticeable cost advantage in the manufacture of the fuel injection pump. In addition, the tolerances of the spray adjustment during the transition from cold star acceleration to normal function can be kept small. Further advantages of advantageous embodiments of the invention can be found in the following description, the drawing and the claims.
  • FIG. 1 shows a schematic illustration of the fuel injection pump according to the invention
  • FIG. 2 shows the pressure curve in the pressure chamber of the pressure control valve or of the control pressure effective at the spray adjustment device in various functional positions of the actuating piston.
  • FIG. 1 shows a part of a distributor fuel injection pump 1 with a spray adjustment device 2, which has an 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 is supported is located in a reset space 9, which is formed by an end face and the wall of the cylinder 3, and an end face of the injection adjusting piston 4, on the other end side of which a spray adjuster working space 6 in the cylinder 3 is delimited.
  • the injection adjuster working space 6 is connected via a throttle bore 7 in the injection adjustment piston 4 to a suction space 8 inside the fuel injection pump.
  • the cylinder 3 has an inlet bore 10 on its cylindrical wall, which is opened or closed via a control edge 11 formed by a bore in the injection adjustment piston 4 that is permanently connected to the resetting space during the axial movement of the injection adjustment piston 4 in the cylinder 3.
  • a relief bore 12 opens into the resetting space 9 of the spray adjustment device 2 via the end face of the cylinder 3, so that this is constantly relieved of pressure via a return line 13 to the fuel tank 14.
  • the suction chamber 8 is supplied with fuel by a feed pump 15, which is driven synchronously with the distributor fuel injection pump 1, via a pressure line 16, the feed pump 15 taking the fuel from the fuel tank 14 via a suction line 17.
  • a bypass line 18, in which a pressure control valve 19 is located, is arranged parallel to the feed pump 15.
  • This has an adjustable wall in the form of a control piston 20, which slides tightly in a cylinder 21 and delimits a pressure chamber 22 on one end side, into which the bypass line 18 opens from the pressure line 16.
  • the control piston 20 delimits a pressure control valve return space 25, in which a return spring 26 is arranged, which is supported on the star piston 20 on the one hand and on the upper end side of the cylinder 21 on the other.
  • a drain line 23 of the pressure chamber 22 is introduced into the cylindrical wall of the cylinder 21, the cross section of which is opened or closed by a control edge 24 formed by the bottom of the control piston 20, depending on the axial position of the control piston 20.
  • This drain line 23 opens via the bypass line 18 into the suction line 17 to the feed pump 15.
  • the pressure control valve reset chamber 25 is connected to the pressure chamber 22 continuously via a throttle 27. Furthermore, the reset space 25 is connected to the fuel tank 14 via a relief line 29. In this relief line 29, a pressure holding valve 30 is arranged, which can block the outflow from the pressure control valve reset chamber 25.
  • This pressure holding valve 30 is designed as a check valve and is closed by a ball valve 31 with a spring element 32, the closing member being able to be pushed open by a temperature-dependent actuating element 33.
  • This actuator 33 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.
  • a relief line 39 leads to the inlet bore 10 in the cylinder 3 of the injection adjustment device 2, an opening cross section being released by the injection adjustment piston 4 from a certain axial position and the fuel from the recovery space 25 of the pressure control valve 19 via the recovery space 9 of the injection adjustment device 2 can flow to the fuel tank 14.
  • the fuel injection pump When the fuel injection pump is operating, its suction space is filled with fuel.
  • the return spring 26 adjusts the control piston 20 to the bottom of the cylinder 21 of the pressure control valve 19 and thus closes the drain line 23 held and closes the circumference of the inlet bore 10.
  • the feed pump 15 is set in motion and generates a pressure in the suction chamber 8 or in the pressure chamber 22 of the pressure control valve 19. Since the relief of the pressure control valve reset chamber 25 when the internal combustion engine is still cold in the pressure control valve 19 via the Pressure holding valve 30 and is blocked by the spray adjustment device 2, the control piston 20 is held in its initial position, and the bypass line 18 remains closed.
  • the temperature-dependent actuator 33 keeps the pressure-maintaining valve 30 open even when the engine is switched off and the fuel pressure drop associated therewith and when the coolant is hot, thus ensuring the constant relief of the pressure control valve return space 25 in the pressure control valve 19. If the engine is now started, the pressure is controlled and, with it, the spray adjustment is also speed-dependent via the pressure control valve 19.
  • the device according to the invention thus enables extreme spray adjustment, up to a degree limited by the adjustment piston of the spray adjuster, only when the internal combustion engine is cold. In this way, the advantage of a strong advance adjustment when the internal combustion engine is cold does not have a disadvantageous effect on starting when the internal combustion engine is at operating temperature.
  • the advantage to be emphasized of the fuel injection pump according to the invention consists in the saving of a pressure valve in the relief line 29 of the pressure control valve 19, in that the speed-dependent control is implemented during the warm-up phase of the engine via the adjusting piston 4 of the spray adjustment device 2 of the distributor fuel injection pump 1.
  • FIG. 2 shows the course of the spray adjustment in a diagram over the speed.
  • the dashed lines show the fuel injection pump according to the invention in relation to the full line of a distributor fuel injection pump without a cold start accelerator. After starting the engine, the rapid build-up of pressure in the suction chamber and the associated steep increase in the start of spraying can be seen (point A - point B).

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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)

Description

Stand der TechnikState of the art

Die Erfindung geht von einer Kraftstoffeinspritzpumpe nach der Gattung des Hauptanspruchs aus. Eine solche ist aus der deutschen Patentanmeldung DE-A-39 12 624 bekannt. Dort wird über eine hydraulische Blockierung des Drucksteuerventils der Förderpumpe dessen Absteuerung verhindert und somit der gesamte geförderte Kraftstoff zum Aufbau des Steuerdrucks verwendet. Auf diese Weise kann auch bei einer kalten Brennkraftmaschine möglichst schnell ein hoher Saugraumdruck und die damit verbundene Spritzverstellung in Richtung früh erreicht werden. Das bekannte Kaltstartsystem besteht aus einer Kraftstoffeinspritzpumpe mit einer Spritzverstelleinrichtung, einer Förderpumpe über die ein in der Zuleitung zur Kraftstoffeinspritzpumpe befindliches Drucksteuerventil den Zufluß zum Saugraum steuert und zwei parallel in der Entlastungsleitung des Drucksteuerventilrückstellraumes angeordnete Ventile, von denen eins in Abhängigkeit von der Betriebstemperatur des Motors und das andere in Abhängigkeit vom Steuerdruck im Saugraum geöffnet wird. Diese beiden Ventile in der Entlastungsleitung des Drucksteuerrückstellraumes ermöglichen in der Warmlaufphase bzw. beim Anlassen des Motors durch eine hydraulische Blockierung der Bypassleitung über das Drucksteuerventil, ein Absteuern des Kraftstoffzuflusses, so daß der gesamte Kraftstoff der Kraftstoffeinspritzpumpe zufließt und in bekannter Weise den Steuerdruck schnell aufbauen kann, was eine Verstellung der Spritzverstelleinrichtung in Richtung früh zur Folge hat. Diese spezielle Frühverstellung wird durch Erreichen eines bestimmten Druckes und dem damit verbundenen Öffnen des Druckventils oder am Ende der Warmlaufphase durch Aufsteuern des Druckhalteventils aufgehoben, wobei die Entlastungsleitung des Rückstellraumes des Drucksteuerventils nun geöffnet ist. Danach wird der auf die Spritzverstelleinrichtung wirkende Druck in bekannter Weise drehzahlabhängig durch das Drucksteuerventil gesteuert. Die Frühverstellung bewirkt eine Verbesserung des Kaltstartverhaltens und des Laufes der Brennkraftmaschine in der Warmlaufphase. Nachteilig bei der genannten Einrichtung ist die aufwendige zusätzliche Anordnung der Druckventile in der Entlastungsleitung des Drucksteuerventils der Förderpumpe' mit dem benötigten Bauraum und den damit verbundenen Kosten. Hieraus leitet sich die Forderung nach einem vereinfachten Aufbau der gesamten Kaltstarteinrichtung für eine Brennkraftmaschine ab.The invention is based on a fuel injection pump according to the preamble of the main claim. Such is known from German patent application DE-A-39 12 624. There, a hydraulic blocking of the pressure control valve of the feed pump prevents it from being deactivated and thus the entire fuel delivered is used to build up the control pressure. In this way, even with a cold internal combustion engine, a high suction chamber pressure and the associated spray adjustment in the direction of early can be achieved as quickly as possible. The known cold start system consists of a fuel injection pump with an injection adjustment device, a feed pump via which a pressure control valve located in the feed line to the fuel injection pump controls the inflow to the suction space and two valves arranged in parallel in the relief line of the pressure control valve return space, one of which depends on the operating temperature of the engine and the other is opened depending on the control pressure in the suction chamber. These two valves in the relief line of the pressure control reset chamber enable the fuel flow to be shut off in the warm-up phase or when the engine is started by hydraulically blocking the bypass line via the pressure control valve, so that all of the fuel flows to the fuel injection pump and can build up the control pressure quickly in a known manner , which results in an advance adjustment of the spray adjustment device. This special advance adjustment is canceled by reaching a certain pressure and the associated opening of the pressure valve or at the end of the warm-up phase by opening the pressure-maintaining valve, the relief line of the reset space of the pressure control valve now being open. 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 early adjustment improves the cold start behavior and the running of the internal combustion engine in the warm-up phase. A disadvantage of the device mentioned is the complex additional arrangement of the pressure valves in the relief line of the pressure control valve of the feed pump, with the required installation space and the associated costs. This leads to the demand for a simplified structure of the entire cold start device for an internal combustion engine.

Vorteile der ErfindungAdvantages of the invention

Die erfindungsgemäße Kraftstoffeinspritzpumpe mit den Merkmalen des Patentanspruchs 1 hat demgegenüber den Vorteil, daß die Position des Stellkolbens der Spritzverstelleinrichtung als drehzahlproportionales Signal genutzt wird, um die Blockierung der Entlastungsleitung des Drucksteuerventils zu steuern. Dadurch fällt ein separates druckgesteuertes Ventil weg, was einen merklichen Kostenvorteil bei der Herstellung der Kraftstoffeinspritzpumpe darstellt. Zudem können die Toleranzen der Spritzverstellage beim, Übergang von Kaltstarbeschleunigungs- auf Normalfunktion klein gehalten werden. Weitere Vorteile kund vorteilhafte Ausgestaltungen der Erfindung sind der nachfolgenden Beschreibung, der Zeichnung und den Ansprüchen entnehmbar.The fuel injection pump according to the invention with the features of claim 1 has the advantage that the position of the actuating piston of the spray adjustment device is used as a speed-proportional signal to control the blocking of the relief line of the pressure control valve. This eliminates a separate pressure-controlled valve, which represents a noticeable cost advantage in the manufacture of the fuel injection pump. In addition, the tolerances of the spray adjustment during the transition from cold star acceleration to normal function can be kept small. Further advantages of advantageous embodiments of the invention can be found in the following description, the drawing and the claims.

Zeichnungdrawing

Ein Ausführungsbeispiel der Erfindung ist in der Zeichnung vereinfacht dargestellt und im folgenden näher beschrieben. Es zeigen die Figur 1 eine schematische Darstellung der erfindungsgemäßen Kraftstoffeinspritzpumpe und die Figur 2 den Druckverlauf im Druckraum des Drucksteuerventils bzw. des an der Spritzverstelleinrichtung wirksamen Steuerdrucks bei verschiedenen Funktionslagen des Stellkolbens.An embodiment of the invention is shown in simplified form in the drawing and described in more detail below. FIG. 1 shows a schematic illustration of the fuel injection pump according to the invention, and FIG. 2 shows the pressure curve in the pressure chamber of the pressure control valve or of the control pressure effective at the spray adjustment device in various functional positions of the actuating piston.

Beschreibung des AusführungsbeispielsDescription of the embodiment

In Figur 1 ist ein Teil einer Verteilerkraftstoffeinspritzpumpe 1 dargestellt mit einer Spritzverstelleinrichtung 2, die einen in einem Zylinder 3 verschiebbaren Verstellkolben 4 aufweist, der auf seiner einen Stirnseite von einer Rückstellfeder 5 beaufschlagt ist, die sich ortsfest an einer Stirnseite des Zylinders 3 abstützt und sich in einem Rückstellraum 9 befindet, der von einer Stirnseite und der Wand des Zylinders 3, sowie einer Stirnseite des Spritzverstellkolbens 4 gebildet wird, auf dessen anderer Stirnseite ein Spritzverstellerarbeitsraum 6 im Zylinder 3 begrenzt wird. Der Spritzverstellerarbeitsraum 6 ist über eine Drosselbohrung, 7 im Spritzverstellkolben 4 mit einem Saugraum 8 im Inneren der Kraftstoffeinspritzpumpe verbunden. Im Bereich des Rückstellraumes 9 weist der Zylinder 3 an seiner zylindrischen Wand eine Eintrittsbohrung 10 auf, die über eine durch eine mit dem Rückstellraum ständig verbundene Bohrung im Spritzverstellkolben 4 gebildete Steuerkante 11 während der axialen Bewegung des Spritzverstellkolbens 4 im Zylinder 3 geöffnet oder verschlossen wird. Zudem mündet über die Stirnseite des Zylinders 3 eine Entlastungsbohrung 12 in den Rückstellraum 9 der Spritzverstelleinrichtung 2, so daß dieser über eine Rücklaufleitung 13 zum Kraftstofftank 14 ständig druckentlastet ist. Der Saugraum 8 wird von einer synchron zur Verteilerkraftstoffeinspritzpumpe 1 angetriebenen Förderpumpe 15 über eine Druckleitung 16 mit Kraftstoff versorgt, wobei die Förderpumpe 15 über eine Saugleitung 17 den Kraftstoff aus dem Kraftstofftank 14 entnimmt. Parallel zur Förderpumpe 15 ist eine Bypassleitung 18 angeordnet, in der sich ein Drucksteuerventil 19 befindet. Dieses weist eine verstellbare Wand in Form eines Steuerkolbens 20, der in einem Zylinder 21 dicht gleitet und auf der einen Stirnseite einen Druckraum 22 begrenzt, in den die Bypassleitung 18 von der Druckleitung 16 einmündet, auf. Auf der anderen Stirnseite begrenzt der Steuerkolben 20 einen Drucksteuerventilrückstellraum 25, in dem eine Rückstellfeder 26 angeordnet ist, die sich am Sternerkolben 20 einerseits und an der oberen Stirnseite des Zylinders 21 andererseits abstützt. Außerdem ist eine Abflußleitung 23 des Druckraumes 22 in die zylindrische Wand des Zylinders 21 eingebracht, deren Querschnitt durch eine vom Boden des Steuerkolbens 20 gebildeten Steuerkante 24 je nach axialer Stellung des Steuerkolbens 20 geöffnet oder verschlossen wird. Diese Abflußleitung 23 mündet über die Bypassleitung 18 wieder in die Saugleitung 17 zur Förderpumpe 15. Der Drucksteuerventilrückstellraum 25 ist mit dem Druckraum 22 ständig über eine Drossel 27 verbunden. Weiterhin ist der Rückstellraum 25 über eine Entlastungsleitung 29 mit dem Kraftstofftank 14 verbunden. In dieser Entlastungsleitung 29 ist ein Druckhalteventil 30 angeordnet, das das Abströmen aus dem Drucksteuerventilrückstellraum 25 blockieren kann. Dieses Druckhalteventil 30 ist als Rückschlagventil ausgebildet und, wird von einem Kugelventil 31 mit Federelement 32 verschlossen, wobei das Verschließglied durch ein temperaturabhängig betätigtes Stellglied 33 aufgestoßen werden kann. Dieses Stellglied 33 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 33 bei betriebswarmer Brennkraftmaschine das Schließglied gegen die Federkraft des Kugelventils 31 aufgestoßen und somit die Entlastungsleitung 29 zum Kraftstofftank 14 hin geöffnet. Parallel zum Druckhalteventil 30 führt eine Entlastungsleitung 39 zur Eintrittsbohrung 10 in den Zylinder 3 der Spritzverstelleinrichtung 2, wobei durch den Spritzverstellkolben 4 ab einer bestimmten axialen Stellung ein Öffnungsquerschnitt freigegeben wird und der Kraftstoff aus dem Rückstellraum 25 des Drucksteuerventils 19 über den Rückstellraum 9 der Spritzverstelleinrichtung 2 zum Kraftstofftank 14 abfließen kann. Im Betrieb der Kraftstoffeinspritzpumpe ist ihr Saugraum mit Kraftstoff gefüllt. Da im Druckraum 22 und im Drucksteuerventilrückstellraum 25 des Drucksteuerventils 19 derselbe Druck anliegt, verstellt die Rückstellfeder 26 den Steuerkolben 20 zum Boden des Zylinders 21 des Drucksteuerventils 19 und verschließt somit die Abflußleitung 23. Auch der Verstellkolben 4 wird dementsprechend von der Rückstellfeder 5 in seiner Ausgangslage gehalten und verschließt mit seinem Umfang die Eintrittsbohrung 10. Beim Start wird die Förderpumpe 15 in Bewegung versetzt und erzeugt einen Druck im Saugraum 8 bzw. im Druckraum 22 des Drucksteuerventils 19. Da die Entlastung des Drucksteuerventilrückstellraumes 25 bei noch kalter Brennkraftmaschine im Drucksteuerventil 19 über das Druckhalteventil 30 und über die Spritzverstelleinrichtung 2 blockiert ist, wird der Steuerkolben 20 in seiner Ausgangslage, gehalten und die Bypassleitung 18 bleibt verschlossen. Infolge dessen strömt der gesamte geförderte Kraftstoff in den Saugraum 8 der Verteilerkraftstoffeinspritzpumpe 1, so daß sich dort sehr schnell ein wirksamer Steuerdruck aufbauen kann. Dieses rasche Ansteigen des Druckes im Saugraum 8, bringt auch einen schnellen Druckanstieg über die Drosselbohrung 7 im Spritzverstellerarbeitsraum 6, wo es dann über eine axiale Bewegung des Verstellkolbens 4 zu einer Spritzbeginnverstellung in Richtung früh kommt. Bei einer Erhöhung der Drehzahl der Brennkraftmaschine und damit der Verteilerkraftstoffeinspritzpumpe steigt der Saugraumdruck weiter an, bis die Lage der Steuerkante 11 des Verstellkolbens 4 die Eintrittsbohrung 10 der Entlastungsleitung 29 des Drucksteuerventilrückstellraumes 25 freigibt. Nun ist die Enlastungsleitung nicht mehr blockiert, der Kraftstoff aus dem Rückstellraum 25 kann über den Rückstellraum 9 der Spritzverstelleinrichtung 2 abfließen, was einen sofortigen Druckabfall im Drucksteuerventilrückstellraum 25 des Drucksteuerventils 19 zur Folge hat. Der von der Förderpumpe 15 im Druckraum 22 erzeugte Druck reicht nun aus, den Steuerkolben 20 gegen die Federkraft der Rückstellfeder 26 zu bewegen und somit über die Steuerkante 24 am Steuerkolben 20 die Abflußleitung 23 freizugeben. Da nun ein Teil des geförderten Kraftstoffes über die Bypassleitung 18 des Drucksteuerventils 19 abfließt, kommt es zu einem Abregeln des steilen Druckanstieges im Saugraum 8 und der damit verbundenen Frühverstellung der Spritzverstelleinrichtung 2. Bei weiterem Drehzahlanstieg ergibt sich ein mit der Drehzahl zunehmender Verlauf des Steuerdruckes, da nun der Drucksteuerventilrückstellraum 25 des Drucksteuerventils 19 entlastet ist und das Drucksteuerventil 19 nun drehzahlabhängig den Druck im Saugraum 8, durch mehr oder weniger öffnen der Abflußdrossel 23 steuert. Das Druckhalteventil 30 wird temperaturabhängig bei einer bestimmten Betriebstemperatur der Brennkraftmaschine ebenfalls öffnen. Dieses Ventil in der Entlastungsleitung 29 des Drucksteuerventilrückstellraumes 25 hat die Aufgabe, die extreme Frühverstellung der Spritzverstelleinrichtung 2 nach Erreichen der Betriebstemperatur zu beenden und beim Anlassen der warmen Brennkraftmaschine einen frühen Spritzbeginn mit der damit verbundenen hohen Schadstoffemission zu vermeiden. Dies wird erreicht, indem das temperaturabhängige Stellglied 33 auch bei abgestelltem Motor und dem damit verbundenen Kraftstoffdruckabfall, bei heißem Kühlmittel das Druckhalteventil 30 geöffnet hält und somit die ständige Entlastung des Drucksteuerventilrückstellraumes 25 im Drucksteuerventil 19 gewährleistet. Wird nun der Motor gestartet, erfolgt die Druckregelung und, damit auch die Spritzverstellung sofort drehzahlabhängig über das Drucksteuerventil 19. Die erfindungsgemäße Einrichtung ermöglicht somit die extreme Spritzverstellung, bis, zu einem durch den Verstellkolben des Spritzverstellers begrenzten Grad, nur bei kalter Brennkraftmaschine. Auf diese Weise wirkt sich der Vorteil einer starken Frühverstellung bei kalter Brennkraftmaschine nicht nachteilig auf das Anlassen bei betriebswarmer Brennkraftmaschine aus. Der hervorzuhebende Vorteil der erfindungsgemäßen Kraftstoffeinspritzpumpe besteht in der Einsparung eines Druckventils in der Entlastungsleitung 29 des Drucksteuerventils 19, indem die drehzahlabhängige Steuerung während der Warmlaufphase des Motors über den Verstellkolben 4 der Spritzverstelleinrichtung2 der Verteilerkraftstoffeinspritzpumpe 1 realisiert wird. In der Figur 2 ist der Verlauf der Spritzverstellung in einem Diagramm über der Drehzahl dargestellt. Dabei zeigt die gestrichelte Linienführung die erfindungsgemäße Kraftstoffeinspritzpumpe gegenüber der Vollinie einer Verteilerkraftstoffeinspritzpumpe ohne Kaltstartbeschleuniger. Nach Anlassen des Motors ist der rasche Druckaufbau im Saugraum und damit verbunden der steile Anstieg des Spritzbeginns zu erkennen (Punkt A - Punkt B). Im Punkt B kommt es mit Erreichen einer bestimmten Frühverstellung und der damit verbundenen Stellung des Verstellkolbens der Spritzverstelleinrichtung zum Öffnen der Entlastungsleitung 29 im Rückstellraum 25 des Drucksteuerventils 19 und der damit verbundenen und bereits beschriebenen Abregelung des Kraftstoffzuflusses zum Saugraum 8 der Verteilerkraftstoffeinspritzpumpe 1. Von diesem Drehzahlpunkt an, bis zum Erreichen der dem Punkt C entsprechenden Drehzahl bleibt der Druck im Saugraum gleich oder steigt nur leicht an. Ab dem Drehzahlpunkt C übernimmt das Drucksteuerventil 19 die übliche drehzahlabhängige Steuerung des Steuerdrucks und damit des Spritzbeginns der Kraftstoffeinspritzpumpe.FIG. 1 shows a part of a distributor fuel injection pump 1 with a spray adjustment device 2, which has an 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 is supported is located in a reset space 9, which is formed by an end face and the wall of the cylinder 3, and an end face of the injection adjusting piston 4, on the other end side of which a spray adjuster working space 6 in the cylinder 3 is delimited. The injection adjuster working space 6 is connected via a throttle bore 7 in the injection adjustment piston 4 to a suction space 8 inside the fuel injection pump. In the area of the resetting space 9, the cylinder 3 has an inlet bore 10 on its cylindrical wall, which is opened or closed via a control edge 11 formed by a bore in the injection adjustment piston 4 that is permanently connected to the resetting space during the axial movement of the injection adjustment piston 4 in the cylinder 3. In addition, a relief bore 12 opens into the resetting space 9 of the spray adjustment device 2 via the end face of the cylinder 3, so that this is constantly relieved of pressure via a return line 13 to the fuel tank 14. The suction chamber 8 is supplied with fuel by a feed pump 15, which is driven synchronously with the distributor fuel injection pump 1, via a pressure line 16, the feed pump 15 taking the fuel from the fuel tank 14 via a suction line 17. A bypass line 18, in which a pressure control valve 19 is located, is arranged parallel to the feed pump 15. This has an adjustable wall in the form of a control piston 20, which slides tightly in a cylinder 21 and delimits a pressure chamber 22 on one end side, into which the bypass line 18 opens from the pressure line 16. On the other end, the control piston 20 delimits a pressure control valve return space 25, in which a return spring 26 is arranged, which is supported on the star piston 20 on the one hand and on the upper end side of the cylinder 21 on the other. In addition, a drain line 23 of the pressure chamber 22 is introduced into the cylindrical wall of the cylinder 21, the cross section of which is opened or closed by a control edge 24 formed by the bottom of the control piston 20, depending on the axial position of the control piston 20. This drain line 23 opens via the bypass line 18 into the suction line 17 to the feed pump 15. The pressure control valve reset chamber 25 is connected to the pressure chamber 22 continuously via a throttle 27. Furthermore, the reset space 25 is connected to the fuel tank 14 via a relief line 29. In this relief line 29, a pressure holding valve 30 is arranged, which can block the outflow from the pressure control valve reset chamber 25. This pressure holding valve 30 is designed as a check valve and is closed by a ball valve 31 with a spring element 32, the closing member being able to be pushed open by a temperature-dependent actuating element 33. This actuator 33 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 is pushed open against the spring force of the ball valve 31 by the actuator 33 when the internal combustion engine is at operating temperature, and the relief line 29 to the fuel tank 14 is thus opened. In parallel to the pressure control valve 30, a relief line 39 leads to the inlet bore 10 in the cylinder 3 of the injection adjustment device 2, an opening cross section being released by the injection adjustment piston 4 from a certain axial position and the fuel from the recovery space 25 of the pressure control valve 19 via the recovery space 9 of the injection adjustment device 2 can flow to the fuel tank 14. When the fuel injection pump is operating, its suction space is filled with fuel. Since the same pressure is present in the pressure chamber 22 and in the pressure control valve return chamber 25 of the pressure control valve 19, the return spring 26 adjusts the control piston 20 to the bottom of the cylinder 21 of the pressure control valve 19 and thus closes the drain line 23 held and closes the circumference of the inlet bore 10. At the start, the feed pump 15 is set in motion and generates a pressure in the suction chamber 8 or in the pressure chamber 22 of the pressure control valve 19. Since the relief of the pressure control valve reset chamber 25 when the internal combustion engine is still cold in the pressure control valve 19 via the Pressure holding valve 30 and is blocked by the spray adjustment device 2, the control piston 20 is held in its initial position, and the bypass line 18 remains closed. As a result, all of the fuel delivered flows into the suction chamber 8 of the distributor fuel injection pump 1, so that an effective control pressure can build up there very quickly. This rapid increase in the pressure in the suction chamber 8 also brings about a rapid rise in pressure via the throttle bore 7 in the injection adjuster working space 6, where an axial start of the adjustment piston 4 then leads to an early injection start. When the speed of the internal combustion engine and thus the distributor fuel injection pump increases, the suction chamber pressure continues to rise until the position of the control edge 11 of the adjusting piston 4 clears the inlet bore 10 of the relief line 29 of the pressure control valve reset chamber 25. Now the relief line is no longer blocked, the fuel from the resetting space 25 can flow out via the resetting space 9 of the spray adjustment device 2, which results in an immediate pressure drop in the pressure control valve resetting space 25 of the pressure control valve 19. The pressure generated by the feed pump 15 in the pressure chamber 22 is now sufficient to move the control piston 20 against the spring force of the return spring 26 and thus to release the drain line 23 via the control edge 24 on the control piston 20. Since part of the delivered fuel now flows through the bypass line 18 of the pressure control valve 19, the steep rise in pressure in the suction chamber 8 is reduced and the associated advance adjustment of the spray adjustment device 2. As the speed increases further, the control pressure increases with the speed, since the pressure control valve reset chamber 25 of the pressure control valve 19 is now relieved and the pressure control valve 19 now controls the pressure in the suction chamber 8 as a function of the speed by opening the discharge throttle 23 more or less. The pressure control valve 30 becomes temperature-dependent at a certain loading also open the drive temperature of the internal combustion engine. This valve in the relief line 29 of the pressure control valve reset chamber 25 has the task of ending the extreme early adjustment of the spray adjustment device 2 after the operating temperature has been reached and of avoiding an early start of spraying with the associated high pollutant emissions when the warm internal combustion engine is started. This is achieved in that the temperature-dependent actuator 33 keeps the pressure-maintaining valve 30 open even when the engine is switched off and the fuel pressure drop associated therewith and when the coolant is hot, thus ensuring the constant relief of the pressure control valve return space 25 in the pressure control valve 19. If the engine is now started, the pressure is controlled and, with it, the spray adjustment is also speed-dependent via the pressure control valve 19. The device according to the invention thus enables extreme spray adjustment, up to a degree limited by the adjustment piston of the spray adjuster, only when the internal combustion engine is cold. In this way, the advantage of a strong advance adjustment when the internal combustion engine is cold does not have a disadvantageous effect on starting when the internal combustion engine is at operating temperature. The advantage to be emphasized of the fuel injection pump according to the invention consists in the saving of a pressure valve in the relief line 29 of the pressure control valve 19, in that the speed-dependent control is implemented during the warm-up phase of the engine via the adjusting piston 4 of the spray adjustment device 2 of the distributor fuel injection pump 1. FIG. 2 shows the course of the spray adjustment in a diagram over the speed. The dashed lines show the fuel injection pump according to the invention in relation to the full line of a distributor fuel injection pump without a cold start accelerator. After starting the engine, the rapid build-up of pressure in the suction chamber and the associated steep increase in the start of spraying can be seen (point A - point B). In point B, when a certain early adjustment and the associated position of the adjusting piston of the spray adjustment device are reached, the relief line 29 in the resetting space 25 of the pressure control valve 19 opens and the associated and already described reduction of the fuel flow to the suction space 8 of the distributor fuel injection pump 1. From this speed point until the speed corresponding to point C is reached, the pressure in the suction chamber remains the same or only increases slightly. From the speed point C, the pressure control valve 19 takes over the usual speed-dependent control of the control pressure and thus the start of injection of the fuel injection pump.

Claims (1)

1. Fuel injection pump for internal combustion engines, particularly distributor-type fuel injection pumps (1), with an injection adjustment device (2) which has an adjusting piston (4) that can be displaced in a cylinder (3), at one end encloses a working space (6) situated in the cylinder (3) and subjected to a control pressure controlled as a function of rotational speed and, at the other end, delimits a restoring space (9) which contains a spring (5) which imposes a restoring force on the adjusting piston (4) and which is relieved via a return line (13), with a feed pump (15) which is driven in synchronism with the fuel injection pump and the delivery pressure of which is controlled as the control pressure by a pressure control valve (19), which has a wall that is acted upon by the control pressure, is adjustable counter to a restoring spring (26) and divides a pressure space (22) from a pressure-control valve restoring space (25) which accommodates the restoring spring (26) and which is connected continuously, via a restrictor hole (27), to the pressure space (22), the adjusting movement of the adjustable wall in the pressure control valve (19) being used to control a drain line (23) leading from the pressure space (22) to a relief space and the pressure-control valve restoring space (25) being relievable via a pressure-maintaining valve (30) whose operation depends on the temperature and via a pressure relief valve which has a control piston which is acted upon by the control pressure, is adjustable counter to a restoring spring and by means of which the passage cross-section of a relief line (29) connected to the pressure-control valve restoring space (25) can be controlled, characterized in that the adjusting piston (4) of the injection adjustment device (2) is used as the control piston of the pressure relief valve for the relief of the pressure-control valve restoring space (25) of the feed pump (15), the said adjusting piston having on a curved outer surface a control opening which is connected to the restoring space (9), is delimited by a control edge (11) and, from a particular displacement position of the adjusting piston (4), can be connected to the relief line (29) of the pressure-control valve restoring space (25), which opens into the cylinder (3).
EP92106301A 1991-05-31 1992-04-11 Fuel injection pump for internal combustion engines Expired - Lifetime EP0515813B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4117813 1991-05-31
DE4117813A DE4117813A1 (en) 1991-05-31 1991-05-31 FUEL INJECTION PUMP FOR INTERNAL COMBUSTION ENGINES

Publications (2)

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EP0515813A1 EP0515813A1 (en) 1992-12-02
EP0515813B1 true EP0515813B1 (en) 1995-03-08

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EP92106301A Expired - Lifetime EP0515813B1 (en) 1991-05-31 1992-04-11 Fuel injection pump for internal combustion engines

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US (1) US5188083A (en)
EP (1) EP0515813B1 (en)
JP (1) JPH05156970A (en)
DE (2) DE4117813A1 (en)

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GB9725415D0 (en) * 1997-12-02 1998-01-28 Lucas Ind Plc Advance arrangement
GB9826348D0 (en) * 1998-12-02 1999-01-27 Lucas Ind Plc Advance arrangement
DE19832842C1 (en) * 1998-07-21 2000-02-17 Bosch Gmbh Robert Fuel delivery system for supplying fuel to an internal combustion engine
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GB0122968D0 (en) * 2001-09-24 2001-11-14 Delphi Tech Inc Advance arrangement
EP2553241B1 (en) 2010-03-30 2019-11-27 Stephen Lee Cunningham Oscillating piston engine
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WO2013158452A1 (en) 2012-04-18 2013-10-24 Stuart Martin A Polygon oscillating piston engine

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Also Published As

Publication number Publication date
US5188083A (en) 1993-02-23
EP0515813A1 (en) 1992-12-02
JPH05156970A (en) 1993-06-22
DE59201577D1 (en) 1995-04-13
DE4117813A1 (en) 1992-12-03

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