EP1357283A2 - Fuel injection system for internal combustion engine - Google Patents

Fuel injection system for internal combustion engine Download PDF

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Publication number
EP1357283A2
EP1357283A2 EP03004643A EP03004643A EP1357283A2 EP 1357283 A2 EP1357283 A2 EP 1357283A2 EP 03004643 A EP03004643 A EP 03004643A EP 03004643 A EP03004643 A EP 03004643A EP 1357283 A2 EP1357283 A2 EP 1357283A2
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EP
European Patent Office
Prior art keywords
pump
fuel
pressure
suction valve
fuel injection
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.)
Granted
Application number
EP03004643A
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German (de)
French (fr)
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EP1357283B1 (en
EP1357283A3 (en
Inventor
Stefan Kieferle
Achim Koehler
Sascha Ambrock
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Robert Bosch GmbH
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Robert Bosch GmbH
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Publication date
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Publication of EP1357283A2 publication Critical patent/EP1357283A2/en
Publication of EP1357283A3 publication Critical patent/EP1357283A3/en
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Publication of EP1357283B1 publication Critical patent/EP1357283B1/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
    • F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
    • F02M59/44—Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; Pumps having transducers, e.g. to measure displacement of pump rack or piston
    • F02M59/46—Valves
    • F02M59/464—Inlet valves of the check valve type
    • 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
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/02—Fuel-injection apparatus having several injectors fed by a common pumping element, or having several pumping elements feeding a common injector; Fuel-injection apparatus having provisions for cutting-out pumps, pumping elements, or injectors; Fuel-injection apparatus having provisions for variably interconnecting pumping elements and injectors alternatively
    • F02M63/0225—Fuel-injection apparatus having a common rail feeding several injectors ; Means for varying pressure in common rails; Pumps feeding common rails

Definitions

  • the invention is based on one Fuel injection device for an internal combustion engine according to the preamble of claim 1.
  • Such a fuel injection device is by DE 198 48 035 A1 known.
  • This fuel injector has a high-pressure pump that is used for a common rail injection system is provided, in which by the High pressure fuel pump under high pressure in a store is promoted. With the memory are on the cylinders of the Internal combustion engine arranged injectors connected. Commonly used in common rail injection systems Delivery pump provided by the fuel from a Storage container is pumped to the high pressure pump.
  • the High pressure pump has several pump elements, each with a working space delimiting in one stroke driven pump piston. It's a in the work space opening suction valve provided that the suction stroke of the Pump piston opens and through the fuel in the Workspace flows in.
  • the suction valve has a through Closing spring acted upon in a closing direction Valve member, with the closing spring on the pump piston supported. At the beginning of the suction stroke of the piston is through this compresses the closing spring the most, so that the Pressure at which the suction valve opens is higher than during the suction stroke of the pump piston during which the closing spring is increasingly relaxed. Under certain Operating conditions of the internal combustion engine, especially in Overrun, no fuel should be generated by the push-up pump be promoted to memory. To ensure this the opening differential pressure of the suction valve becomes relatively high set, for example to at least 2 bar. this leads to however, that the delivery rate of the high pressure pump is not is optimal.
  • the fuel injection device according to the invention with the Features according to claim 1 has the advantage that the minimum opening differential pressure of the suction valve very much low and therefore the delivery rate of the high pressure pump is improved.
  • FIG. 1 shows a Fuel injection device for an internal combustion engine of a motor vehicle in a schematic representation with a High-pressure pump
  • Figure 2 one designated in Figure 1 with II Section of the high pressure pump in an enlarged view with a pump piston at top dead center
  • FIG. 3 Section II with the pump piston in a lower one Dead center.
  • FIG. 1 is a fuel injection device for a Internal combustion engine, for example of a motor vehicle shown.
  • the internal combustion engine is preferably one self-igniting internal combustion engine and has one or several cylinders.
  • the fuel injector has a feed pump 10 which, for example, in a Fuel tank 12 of the motor vehicle arranged is, however, also be arranged outside the container 12 can.
  • the feed pump 10 can be an electric one Have drive motor and sucks in, for example Prefilter 14 fuel from the fuel tank 12 on.
  • the feed pump 10 can also be mechanical, for example are driven by the internal combustion engine. From the outlet the feed pump 10 leads a line 16 to a High pressure pump 18. Between the feed pump 10 and the High pressure pump 18 is a fuel filter in line 16 20 arranged, which is designed as a fine filter and that of the fuel delivered by the feed pump 10 is flowed through.
  • the high pressure pump 18 has, for example, several Pump elements 22, each one in one Have cylinder bore 24 guided pump piston 26, the via an eccentric drive 28 in one stroke is driven.
  • the high pressure pump 18 is preferred mechanically driven by the internal combustion engine.
  • the fuel delivered by the high pressure pump 18 is about a line 30 is fed to a memory 32.
  • each Pump element 22 has a delimited by the pump piston 26 Working space 34 into which an inlet from the feed pump 10 opens out and from which a sequence leads to the memory 32.
  • suction valve 36 In the inflow of each pump element 22 is in the work space 34 opening suction valve 36 provided and in the course of each Pump element 22 is an opening towards the reservoir 32 Pressure valve 38 is provided.
  • each injector 40 for each cylinder of the internal combustion engine 40 provided by the fuel in the combustion chamber of the Cylinder is injected.
  • Each injector 40 is over one Line 42 connected to the memory 32 and the opening of the Injector 40 for fuel injection is replaced by a electrically controlled valve 44 controlled by a electronic control device 46 is controlled.
  • a electrically controlled valve 44 controlled by a electronic control device 46 is controlled.
  • Of the injectors 40 can return 41 to Remove fuel tank 12 for not injected fuel.
  • a pressure valve 48 can be provided, that opens when a specified pressure is exceeded and a return via a line 50 from the memory 32 in the Fuel tank 12 releases.
  • a pressure sensor 52 through which the pressure is detected in the memory 32 and electrically with the Control device 46 is connected, which is thus a signal for the pressure prevailing in the accumulator 32 is supplied.
  • a high pressure pump 18 can be provided with a return 54 which, for example, leak a leakage of fuel can and which can open into line 50.
  • a fuel metering device 60 In the connection between the feed pump 10 and the High pressure pump 18 is a fuel metering device 60 arranged through which a flow cross section of the Connection to the high pressure pump 18 is set.
  • the Fuel metering device 60 is by the Control device 46 driven.
  • the Fuel metering device 60 has a flow control valve 62 on and an actuator 64 by the control device 46 is controlled.
  • By means of the flow control valve 62 can the flow cross section of the connection to High pressure pump 18 can be continuously adjusted between Zero and a maximum flow area.
  • actuator 64 an electromagnet or a piezo actuator can be used, each by the control device 46 with a defined electrical voltage and is supplied the flow control valve 62 in a defined position brings in which this has a defined flow cross-section releases.
  • the Internal combustion engine is allowed through the high pressure pump 18 has no fuel in the accumulator 32 be promoted.
  • the Fuel metering device 60 the flow cross section of the feed pump 10 to the high pressure pump 18 completely closed, so that the high pressure pump 18 no fuel flows more.
  • a target pressure in the memory 32nd specified.
  • the pressure sensor 52 receives the Control device 46 a signal for the actual pressure in the memory 32.
  • the pressure in the memory 32 is dependent on that by the High pressure pump 18 promoted in the memory 32 Fuel quantity.
  • the pumped by the high pressure pump 18 The amount of fuel can be changed by using of the fuel metering device 60 is the flow cross section the connection to the feed pump 10 is changed.
  • the Fuel metering device 60 is by the Control device 46 controlled so that this in the Connection to the feed pump 10 a flow cross section sets that is so large that that of the high pressure pump 18th inflowing amount of fuel is so large that by the High pressure pump 18 pumped into the memory 32 Amount of fuel to maintain the specified Target pressure in the memory 32 is sufficient. If the actual pressure in Memory 32 is less than the target pressure, so by the high pressure pump 18 has too little fuel promoted and by the control device Fuel metering device 60 is controlled such that it a larger flow cross section in the connection to Feed pump 10 releases and thus by the High pressure pump 18 delivered amount of fuel is increased.
  • the high pressure pump 18 becomes too large Fuel quantity promoted and by the control device 46 the fuel metering device 60 is controlled in such a way that this has a smaller flow cross section in the Releases connection to the feed pump 10 and thus through the high pressure pump 18 reduced amount of fuel delivered becomes.
  • the suction valve is shown below with reference to FIGS 36 of a pump element 22 explained in detail, all Pump elements 22 are identical.
  • one Housing part 70 of high-pressure pump 18 is an inlet channel 72 for the fuel delivered by the feed pump 10 in the Working space 34 is formed.
  • a valve seat 74 formed, for example, at least is approximately conical.
  • the suction valve 36 has a valve member 76, for example in the form of a Ball is formed and that with the valve seat 74 Control of the connection of the inlet channel 72 with the Working space 34 cooperates.
  • the valve member 76 is for example, arranged in a direction toward the pump piston 26 Carrier part 78 added.
  • the suction valve 36 also has a closing spring 80, which, for example, as Helical compression spring is formed and between the Pump piston 26 and the support member 78 is clamped.
  • a closing spring 80 becomes the valve member 76 in Closing direction pressed toward valve seat 74.
  • the Valve member 76 is also by the in the working space 34th prevailing pressure in the closing direction.
  • the pump piston 26 has on its the valve member 76 end facing a reduced diameter extension 82 on, at the transition from the full diameter of the Pump piston 26, on which it is in the cylinder bore 24 an annular shoulder 84 for the extension 82 is formed, on which the closing spring 80 is supported.
  • the Closing spring 80 surrounds extension 82 and carrier part 78 is then arranged on the extension 82. If the pump piston 26 is at its top dead center, the is the stroke position in which the pump piston 26 is closest is arranged towards the housing part 70, so between the Extension 82 of the pump piston 26 and the carrier part 78 Distance in the direction of the longitudinal axis 27 of the pump piston 26 present when the valve member 76 is in its Is in the closed position in which it is on the valve seat 74 is applied.
  • the front end of the Extension 82 of the pump piston 26 a stop Limiting the opening movement of the valve member 76 forms by the carrier part 78 coming to rest on the extension 82. If the pump piston 26 as shown in FIG is at its top dead center, the closing spring 80 of the suction valve 36 highly compressed and exercises accordingly a high force on the valve member 76 with which this is pressed against the valve seat 74. The one through the Closing spring 80 and by the in the working space 34th prevailing pressure generated force on the valve member 76th acts on the pressure prevailing in the inlet channel 72 the valve member 76 generates force in the opening direction opposite.
  • the pump piston 26 moves from its top dead center according to Figure 2 to its bottom dead center according to Figure 3.
  • the Closing spring 80 increasingly relaxed, so that this one less force in the closing direction on the valve member 76 causes and according to the opening differential pressure of the Suction valve 36 is lower. If the pump piston 26 is at its top dead center at the start of the suction stroke, so is the opening differential pressure of the suction valve 36 am highest and is subsequently called the maximum Opening differential pressure called.
  • the opening differential pressure decreases, being in an area of the middle suction stroke that is a middle stroke position of the pump piston 26 between its top dead center and its bottom dead center average opening differential pressure of the suction valve 36 results.
  • the opening differential pressure of the suction valve 36 When the pump piston 26 is at its bottom dead center is the opening differential pressure of the suction valve 36 least and is subsequently considered to be the minimum Opening differential pressure called. It is provided that the minimum opening differential pressure of the suction valve 36 is less than 0.9 bar, preferably at most 0.8 bar.
  • the mean opening differential pressure and the maximum Opening differential pressure of the suction valve 36 are then dependent from the spring rate c of the closing spring 80, that is the Change in the force generated by this in relation to the Travel, and from the stroke of the pump piston 26 between the top and bottom dead center.
  • the spring rate c the Closing spring 80 can have a small value, whereby the force exerted by the closing spring 80 on the Valve member 76, however, over the relatively large suction stroke of the Pump piston 26 changes significantly.
  • the middle one Opening differential pressure of the suction valve 36 is greater than 0.9 bar.
  • the ratio between the middle Opening differential pressure and the minimum Opening differential pressure of suction valve 36 is greater than 1 and is at most about 10.

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

Abstract

The device has a high pressure pump (18) feeding fuel under high pressure to a storage device (32) connected to injectors (40), a delivery pump (10) feeding fuel to the high pressure pump from a tank (12). The high pressure pump working chamber (34) is connected to the pressure side of the delivery pump and contains a suction valve (36) opening to the working chamber and with a minimal opening pressure difference less than 0.9 bar.

Description

Stand der TechnikState of the art

Die Erfindung geht aus von einer Kraftstoffeinspritzeinrichtung für eine Brennkraftmaschine nach der Gattung des Anspruchs 1.The invention is based on one Fuel injection device for an internal combustion engine according to the preamble of claim 1.

Eine solche Kraftstoffeinspritzeinrichtung ist durch die DE 198 48 035 A1 bekannt. Diese Kraftstoffeinspritzeinrichtung weist eine Hochdruckpumpe auf, die für ein Common-Rail-Einspritzsystem vorgesehen ist, bei dem durch die Hochdruckpumpe Kraftstoff unter Hochdruck in einen Speicher gefördert wird. Mit dem Speicher sind an den Zylindern der Brennkraftmaschine angeordnete Injektoren verbunden. Üblicherweise ist bei Common-Rail-Einspritzsystemen eine Förderpumpe vorgesehen, durch die Kraftstoff aus einem Vorratsbehälter zur Hochdruckpumpe gefördert wird. Die Hochdruckpumpe weist mehrere Pumpenelemente auf, mit jeweils einem einen Arbeitsraum begrenzenden, in einer Hubbewegung angetriebenen Pumpenkolben. Es ist ein in den Arbeitsraum öffnendes Saugventil vorgesehen, das beim Saughub des Pumpenkolbens öffnet und durch das Kraftstoff in den Arbeitsraum einströmt. Das Saugventil weist ein durch eine Schließfeder in einer Schließrichtung beaufschlagtes Ventilglied auf, wobei sich die Schließfeder am Pumpenkolben abstützt. Zu Beginn des Saughubs des Kolbens ist durch diesen die Schließfeder am stärksten komprimiert, so daß der Druck, bei dem das Saugventil öffnet höher ist als während des Saughubs des Pumpenkolbens, während dem die Schließfeder zunehmend entspannt wird. Unter bestimmten Betriebsbedingungen der Brennkraftmaschine, insbesondere im Schubbetrieb, soll durch die Hochdrückpumpe kein Kraftstoff in den Speicher gefördert werden. Um dies sicherzustellen, wird der Öffnungsdifferenzdruck des Saugventils relativ hoch eingestellt, beispielsweise auf mindestens 2 bar. Dies führt jedoch dazu, daß der Liefergrad der Hochdruckpumpe nicht optimal ist.Such a fuel injection device is by DE 198 48 035 A1 known. This fuel injector has a high-pressure pump that is used for a common rail injection system is provided, in which by the High pressure fuel pump under high pressure in a store is promoted. With the memory are on the cylinders of the Internal combustion engine arranged injectors connected. Commonly used in common rail injection systems Delivery pump provided by the fuel from a Storage container is pumped to the high pressure pump. The High pressure pump has several pump elements, each with a working space delimiting in one stroke driven pump piston. It's a in the work space opening suction valve provided that the suction stroke of the Pump piston opens and through the fuel in the Workspace flows in. The suction valve has a through Closing spring acted upon in a closing direction Valve member, with the closing spring on the pump piston supported. At the beginning of the suction stroke of the piston is through this compresses the closing spring the most, so that the Pressure at which the suction valve opens is higher than during the suction stroke of the pump piston during which the closing spring is increasingly relaxed. Under certain Operating conditions of the internal combustion engine, especially in Overrun, no fuel should be generated by the push-up pump be promoted to memory. To ensure this the opening differential pressure of the suction valve becomes relatively high set, for example to at least 2 bar. this leads to however, that the delivery rate of the high pressure pump is not is optimal.

Vorteile der ErfindungAdvantages of the invention

Die erfindungsgemäße Kraftstoffeinspritzeinrichtung mit den Merkmalen gemäß Anspruch 1 hat demgegenüber den Vorteil, daß der minimale Öffnungsdifferenzdruck des Saugventils sehr gering und dadurch der Liefergrad der Hochdruckpumpe verbessert ist.The fuel injection device according to the invention with the Features according to claim 1 has the advantage that the minimum opening differential pressure of the suction valve very much low and therefore the delivery rate of the high pressure pump is improved.

In den abhängigen Ansprüchen sind vorteilhafte Ausgestaltungen und Weiterbildungen der erfindungsgemäßen Kraftstoffeinspritzeinrichtung angegeben. Die Ausbildung gemäß Anspruch 5 ermöglicht es, daß eine Nullförderung der Hochdruckpumpe bei geringem Öffnungsdifferenzdruck des Saugventils erreicht werden kann, indem der Durchflußquerschnitt durch die Kraftstoffzumeßeinrichtung vollständig verschlossen wird.In the dependent claims are advantageous Refinements and developments of the invention Fuel injector specified. Training according to claim 5 enables zero funding of High pressure pump with low opening differential pressure of the Suction valve can be achieved by the Flow cross section through the fuel metering device is completely closed.

Zeichnungdrawing

Ein Ausführungsbeispiel der Erfindung ist in der Zeichnung dargestellt und in der nachfolgenden Beschreibung näher erläutert. Es zeigen Figur 1 eine Kraftstoffeinspritzeinrichtung für eine Brennkraftmaschine eines Kraftfahrzeugs in schematischer Darstellung mit einer Hochdruckpumpe, Figur 2 einen in Figur 1 mit II bezeichneten Ausschnitt der Hochdruckpumpe in vergrößerter Darstellung mit einem Pumpenkolben in einem oberen Totpunkt und Figur 3 den Ausschnitt II mit dem Pumpenkolben in einem unteren Totpunkt.An embodiment of the invention is in the drawing shown and in the description below explained. 1 shows a Fuel injection device for an internal combustion engine of a motor vehicle in a schematic representation with a High-pressure pump, Figure 2 one designated in Figure 1 with II Section of the high pressure pump in an enlarged view with a pump piston at top dead center and FIG. 3 Section II with the pump piston in a lower one Dead center.

Beschreibung des AusführungsbeispielsDescription of the embodiment

In Figur 1 ist eine Kraftstoffeinspritzeinrichtung für eine Brennkraftmaschine beispielsweise eines Kraftfahrzeugs dargestellt. Die Brennkraftmaschine ist vorzugsweise eine selbstzündende Brennkraftmaschine und weist einen oder mehrere Zylinder auf. Die Kraftstoffeinspritzeinrichtung weist eine Förderpumpe 10 auf, die beispielsweise in einem Kraftstoffvorratsbehälter 12 des Kraftfahrzeugs angeordnet ist, jedoch auch außerhalb des Behälters 12 angeordnet sein kann. Die Förderpumpe 10 kann einen elektrischen Antriebsmotor aufweisen und saugt beispielsweise über ein Vorfilter 14 Kraftstoff aus dem Kraftstoffvorratsbehälter 12 an. Die Förderpumpe 10 kann auch beispielsweise mechanisch durch die Brennkraftmaschine angetrieben werden. Vom Auslass der Förderpumpe 10 führt eine Leitung 16 zu einer Hochdruckpumpe 18. Zwischen der Förderpumpe 10 und der Hochdruckpumpe 18 ist in der Leitung 16 ein Kraftstoffilter 20 angeordnet, das als Feinfilter ausgebildet ist und das von dem durch die Förderpumpe 10 geförderten Kraftstoff durchströmt wird.In Figure 1 is a fuel injection device for a Internal combustion engine, for example of a motor vehicle shown. The internal combustion engine is preferably one self-igniting internal combustion engine and has one or several cylinders. The fuel injector has a feed pump 10 which, for example, in a Fuel tank 12 of the motor vehicle arranged is, however, also be arranged outside the container 12 can. The feed pump 10 can be an electric one Have drive motor and sucks in, for example Prefilter 14 fuel from the fuel tank 12 on. The feed pump 10 can also be mechanical, for example are driven by the internal combustion engine. From the outlet the feed pump 10 leads a line 16 to a High pressure pump 18. Between the feed pump 10 and the High pressure pump 18 is a fuel filter in line 16 20 arranged, which is designed as a fine filter and that of the fuel delivered by the feed pump 10 is flowed through.

Die Hochdruckpumpe 18 weist beispielsweise mehrere Pumpenelemente 22 auf, die jeweils einen in einer Zylinderbohrung 24 geführten Pumpenkolben 26 aufweisen, der über einen Exzenterantrieb 28 in einer Hubbewegung angetrieben wird. Die Hochdruckpumpe 18 wird vorzugsweise mechanisch durch die Brennkraftmaschine angetrieben. Der durch die Hochdruckpumpe 18 geförderte Kraftstoff wird über eine Leitung 30 einem Speicher 32 zugeführt. Jedes Pumpenelement 22 weist einen vom Pumpenkolben 26 begrenzten Arbeitsraum 34 auf, in den ein Zulauf von der Förderpumpe 10 her mündet und von dem ein Ablauf zum Speicher 32 abführt. Im Zulauf jedes Pumpenelements 22 ist ein in den Arbeitsraum 34 öffnendes Saugventil 36 vorgesehen und im Ablauf jedes Pumpenelements 22 ist ein zum Speicher 32 hin öffnendes Druckventil 38 vorgesehen. Beim Saughub des Pumpenkolben 26, wenn dieser sich radial nach innen bewegt, öffnet das jeweilige Saugventil 36 und in den Arbeitsraum 34 strömt Kraftstoff von der Förderpumpe 10 ein, während das Druckventil 38 geschlossen ist. Beim Förderhub des Pumpenkolbens 26, wenn dieser sich radial nach außen bewegt, öffnet das jeweilige Druckventil 38 und aus dem Arbeitsraum 34 strömt Kraftstoff zum Speicher 32 hin ab, während das Saugventil 36 geschlossen ist.The high pressure pump 18 has, for example, several Pump elements 22, each one in one Have cylinder bore 24 guided pump piston 26, the via an eccentric drive 28 in one stroke is driven. The high pressure pump 18 is preferred mechanically driven by the internal combustion engine. The fuel delivered by the high pressure pump 18 is about a line 30 is fed to a memory 32. each Pump element 22 has a delimited by the pump piston 26 Working space 34 into which an inlet from the feed pump 10 opens out and from which a sequence leads to the memory 32. In the inflow of each pump element 22 is in the work space 34 opening suction valve 36 provided and in the course of each Pump element 22 is an opening towards the reservoir 32 Pressure valve 38 is provided. During the suction stroke of the pump piston 26, if it moves radially inwards, that opens respective suction valve 36 and flows into the working space 34 Fuel from the feed pump 10 while the Pressure valve 38 is closed. During the delivery stroke of the Pump piston 26 when it moves radially outward opens the respective pressure valve 38 and from the work area 34 fuel flows out to the accumulator 32 while the Suction valve 36 is closed.

Für jeden Zylinder der Brennkraftmaschine ist ein Injektor 40 vorgesehen, durch den Kraftstoff in den Brennraum des Zylinders eingespritzt wird. Jeder Injektor 40 ist über eine Leitung 42 mit dem Speicher 32 verbunden und die Öffnung des Injektors 40 zur Kraftstoffeinspritzung wird durch ein elektrisch angesteuertes Ventil 44 gesteuert, das von einer elektronischen Steuereinrichtung 46 angesteuert wird. Von den Injektoren 40 kann ein Rücklauf 41 zum Kraftstoffvorratsbehälter 12 abführen für nicht eingespritzten Kraftstoff.There is an injector for each cylinder of the internal combustion engine 40 provided by the fuel in the combustion chamber of the Cylinder is injected. Each injector 40 is over one Line 42 connected to the memory 32 and the opening of the Injector 40 for fuel injection is replaced by a electrically controlled valve 44 controlled by a electronic control device 46 is controlled. Of the injectors 40 can return 41 to Remove fuel tank 12 for not injected fuel.

Zur Steuerung und/oder Begrenzung des im Speicher 32 herrschenden Drucks kann ein Druckventil 48 vorgesehen sein, das bei Überschreiten eines vorgegeben Drucks öffnet und einen Rücklauf über eine Leitung 50 vom Speicher 32 in den Kraftstoffvorratsbehälter 12 freigibt. Am Speicher 32 ist außerdem ein Drucksensor 52 angeordnet, durch den der Druck im Speicher 32 erfasst wird und der elektrisch mit der Steuereinrichtung 46 verbunden ist, der somit ein Signal für den im Speicher 32 herrschenden Druck zugeführt wird. An der Hochdruckpumpe 18 kann ein Rücklauf 54 vorgesehen sein, über den beispielsweise eine Leckmenge an Kraftstoff abfließen kann und der in die Leitung 50 münden kann.To control and / or limit the amount in memory 32 prevailing pressure, a pressure valve 48 can be provided, that opens when a specified pressure is exceeded and a return via a line 50 from the memory 32 in the Fuel tank 12 releases. At the memory 32 also arranged a pressure sensor 52 through which the pressure is detected in the memory 32 and electrically with the Control device 46 is connected, which is thus a signal for the pressure prevailing in the accumulator 32 is supplied. At the A high pressure pump 18 can be provided with a return 54 which, for example, leak a leakage of fuel can and which can open into line 50.

In der Verbindung zwischen der Förderpumpe 10 und der Hochdruckpumpe 18 ist eine Kraftstoffzumeßeinrichtung 60 angeordnet, durch die ein Durchflußquerschnitt der Verbindung zur Hochdruckpumpe 18 eingestellt wird. Die Kraftstoffzumeßeinrichtung 60 wird durch die Steuereinrichtung 46 angesteuert. Die Kraftstoffzumeßeinrichtung 60 weist ein Durchflußregelventil 62 auf und einen Aktor 64, der durch die Steuereinrichtung 46 angesteuert wird. Mittels des Durchflußregelventils 62 kann der Durchflußquerschnitt der Verbindung zur Hochdruckpumpe 18 kontinuierlich verstellt werden zwischen Null und einem maximalen Durchflußquerschnitt. Als Aktor 64 kann ein Elektromagnet oder ein Piezoaktor verwendet werden, der jeweils durch die Steuereinrichtung 46 mit einer definierten elektrischen Spannung versorgt wird und dabei das Durchflußregelventil 62 in eine definierte Stellung bringt, in der dieses einen definierten Durchflußquerschnitt freigibt. Unter bestimmten Betriebsbedingungen der Brennkraftmaschine, insbesondere im Schubbetrieb, darf durch die Hochdruckpumpe 18 kein Kraftstoff in den Speicher 32 gefördert werden. Hierzu wird durch die Kraftstoffzumeßeinrichtung 60 der Durchflußquerschnitt von der Förderpumpe 10 zur Hochdruckpumpe 18 vollständig verschlossen, so daß der Hochdruckpumpe 18 kein Kraftstoff mehr zufließt.In the connection between the feed pump 10 and the High pressure pump 18 is a fuel metering device 60 arranged through which a flow cross section of the Connection to the high pressure pump 18 is set. The Fuel metering device 60 is by the Control device 46 driven. The Fuel metering device 60 has a flow control valve 62 on and an actuator 64 by the control device 46 is controlled. By means of the flow control valve 62 can the flow cross section of the connection to High pressure pump 18 can be continuously adjusted between Zero and a maximum flow area. As actuator 64 an electromagnet or a piezo actuator can be used, each by the control device 46 with a defined electrical voltage and is supplied the flow control valve 62 in a defined position brings in which this has a defined flow cross-section releases. Under certain operating conditions the Internal combustion engine, especially in overrun mode, is allowed through the high pressure pump 18 has no fuel in the accumulator 32 be promoted. For this, the Fuel metering device 60 the flow cross section of the feed pump 10 to the high pressure pump 18 completely closed, so that the high pressure pump 18 no fuel flows more.

Abhängig von Betriebsparametern der Brennkraftmaschine, wie beispielsweise Drehzahl, Last und anderen, wird durch die Steuereinrichtung 46 ein Solldruck im Speicher 32 vorgegeben. Durch den Drucksensor 52 erhält die Steuereinrichtung 46 ein Signal für den Istdruck im Speicher 32. Der Druck im Speicher 32 ist abhängig von der durch die Hochdruckpumpe 18 in den Speicher 32 geförderten Kraftstoffmenge. Die durch die Hochdruckpumpe 18 geförderte Kraftstoffmenge kann dadurch verändert werden, daß mittels der Kraftstoffzumeßeinrichtung 60 der Durchflußquerschnitt der Verbindung zur Förderpumpe 10 verändert wird. Die Kraftstoffzumeßeinrichtung 60 wird durch die Steuereinrichtung 46 derart angesteuert, daß diese in der Verbindung zur Förderpumpe 10 einen Durchflußquerschnitt einstellt, der so groß ist, daß die der Hochdruckpumpe 18 zufließende Kraftstoffmenge so groß ist, daß die durch die Hochdruckpumpe 18 in den Speicher 32 geförderte Kraftstoffmenge zur Aufrechterhaltung des vorgegebenen Solldrucks im Speicher 32 ausreicht. Wenn der Istdruck im Speicher 32 geringer ist als der Solldruck, so wird durch die Hochdruckpumpe 18 eine zu geringe Kraftstoffmenge gefördert und durch die Steuereinrichtung wird die Kraftstoffzumeßeinrichtung 60 derart angesteuert, daß diese einen größeren Durchflußquerschnitt in der Verbindung zur Förderpumpe 10 freigibt und somit die durch die Hochdruckpumpe 18 geförderte Kraftstoffmenge erhöht wird. Wenn der Istdruck im Speicher 32 höher ist als der Solldruck, so wird durch die Hochdruckpumpe 18 eine zu große Kraftstoffmenge gefördert und durch die Steuereinrichtung 46 wird die Kraftstoffzumeßeinrichtung 60 derart angesteuert, daß diese einen kleineren Durchflußquerschnitt in der Verbindung zur Förderpumpe 10 freigibt und somit die durch die Hochdruckpumpe 18 geförderte Kraftstoffmenge verringert wird.Depending on the operating parameters of the internal combustion engine, such as for example speed, load and other, is determined by the Control device 46 a target pressure in the memory 32nd specified. The pressure sensor 52 receives the Control device 46 a signal for the actual pressure in the memory 32. The pressure in the memory 32 is dependent on that by the High pressure pump 18 promoted in the memory 32 Fuel quantity. The pumped by the high pressure pump 18 The amount of fuel can be changed by using of the fuel metering device 60 is the flow cross section the connection to the feed pump 10 is changed. The Fuel metering device 60 is by the Control device 46 controlled so that this in the Connection to the feed pump 10 a flow cross section sets that is so large that that of the high pressure pump 18th inflowing amount of fuel is so large that by the High pressure pump 18 pumped into the memory 32 Amount of fuel to maintain the specified Target pressure in the memory 32 is sufficient. If the actual pressure in Memory 32 is less than the target pressure, so by the high pressure pump 18 has too little fuel promoted and by the control device Fuel metering device 60 is controlled such that it a larger flow cross section in the connection to Feed pump 10 releases and thus by the High pressure pump 18 delivered amount of fuel is increased. If the actual pressure in the memory 32 is higher than that Desired pressure, the high pressure pump 18 becomes too large Fuel quantity promoted and by the control device 46 the fuel metering device 60 is controlled in such a way that this has a smaller flow cross section in the Releases connection to the feed pump 10 and thus through the high pressure pump 18 reduced amount of fuel delivered becomes.

Anhand der Figuren 2 und 3 wird nachfolgend das Saugventil 36 eines Pumpenelements 22 näher erläutert, wobei sämtliche Pumpenelemente 22 gleich ausgebildet sind. In einem Gehäuseteil 70 der Hochdruckpumpe 18 ist ein Zulaufkanal 72 für den von der Förderpumpe 10 geförderten Kraftstoff in den Arbeitsraum 34 ausgebildet. An der Mündung des Zulaufkanals 72 in den Arbeitsraum 34 ist dem Arbeitsraum 34 zugewandt ein Ventilsitz 74 ausgebildet, der beispielsweise zumindest annähernd konisch ausgebildet ist. Das Saugventil 36 weist ein Ventilglied 76 auf, das beispielsweise in Form einer Kugel ausgebildet ist und das mit dem Ventilsitz 74 zur Steuerung der Verbindung des Zulaufkanals 72 mit dem Arbeitsraum 34 zusammenwirkt. Das Ventilglied 76 ist beispielsweise in einem zum Pumpenkolben 26 hin angeordneten Trägerteil 78 aufgenommen. Das Saugventil 36 weist außerdem eine Schließfeder 80 auf, die beispielsweise als Schraubendruckfeder ausgebildet ist und die zwischen dem Pumpenkolben 26 und dem Trägerteil 78 eingespannt ist. Durch die Schließfeder 80 wird das Ventilglied 76 in Schließrichtung zum Ventilsitz 74 hin gedrückt. Das Ventilglied 76 wird außerdem durch den im Arbeitsraum 34 herrschenden Druck in Schließrichtung beaufschlagt.The suction valve is shown below with reference to FIGS 36 of a pump element 22 explained in detail, all Pump elements 22 are identical. In one Housing part 70 of high-pressure pump 18 is an inlet channel 72 for the fuel delivered by the feed pump 10 in the Working space 34 is formed. At the mouth of the inlet channel 72 in the working space 34 faces the working space 34 a valve seat 74 formed, for example, at least is approximately conical. The suction valve 36 has a valve member 76, for example in the form of a Ball is formed and that with the valve seat 74 Control of the connection of the inlet channel 72 with the Working space 34 cooperates. The valve member 76 is for example, arranged in a direction toward the pump piston 26 Carrier part 78 added. The suction valve 36 also has a closing spring 80, which, for example, as Helical compression spring is formed and between the Pump piston 26 and the support member 78 is clamped. By the closing spring 80 becomes the valve member 76 in Closing direction pressed toward valve seat 74. The Valve member 76 is also by the in the working space 34th prevailing pressure in the closing direction.

Der Pumpenkolben 26 weist an seinem dem Ventilglied 76 zugewandten Ende einen im Durchmesser verkleinerten Fortsatz 82 auf, wobei am Übergang vom vollen Durchmesser des Pumpenkolbens 26, an dem dieser in der Zylinderbohrung 24 dicht geführt ist, zum Fortsatz 82 eine Ringschulter 84 gebildet ist, an der sich die Schließfeder 80 abstützt. Die Schließfeder 80 umgibt den Fortsatz 82 und das Trägerteil 78 ist an den Fortsatz 82 anschließend angeordnet. Wenn sich der Pumpenkolben 26 in seinem oberen Totpunkt befindet, das ist die Hubstellung, in der der Pumpenkolben 26 am nächsten zum Gehäuseteil 70 hin angeordnet ist, so ist zwischen dem Fortsatz 82 des Pumpenkolbens 26 und dem Trägerteil 78 ein Abstand in Richtung der Längsachse 27 des Pumpenkolbens 26 vorhanden, wenn sich das Ventilglied 76 in seiner Schließstellung befindet, in der es am Ventilsitz 74 anliegt. Es kann vorgesehen sein, daß das Stirnende des Fortsatzes 82 des Pumpenkolbens 26 einen Anschlag zur Begrenzung der Öffnungsbewegung des Ventilglieds 76 bildet, indem das Trägerteil 78 am Fortsatz 82 zur Anlage kommt. Wenn sich der Pumpenkolben 26 wie in Figur 2 dargestellt in seinem oberen Totpunkt befindet, so ist die Schließfeder 80 des Saugventils 36 stark komprimiert und übt entsprechend eine hohe Kraft auf das Ventilglied 76 aus, mit der dieses gegen den Ventilsitz 74 gedrückt wird. Der durch die Schließfeder 80 und der durch den im Arbeitsraum 34 herrschenden Druck erzeugten Kraft auf das Ventilglied 76 wirkt die durch den im Zulaufkanal 72 herrschenden Druck auf das Ventilglied 76 erzeugte Kraft in Öffnungsrichtung entgegen. Wenn die durch den im Zulaufkanal 72 herrschenden Druck auf das Ventilglied 76 erzeugte Kraft größer ist als die durch die Schließfeder 80 und den im Arbeitsraum 34 herrschenden Druck auf das Ventilglied 76 bewirkte Kraft, so bewegt sich das Ventilglied 76 gegen die Kraft der Schließfeder 80 in Öffnungsrichtung und gibt die Mündung des Zulaufkanals 72 in den Arbeitsraum 34 frei. Der Druck, bei dem das Ventilglied 76 sich in Öffnungsrichtung bewegt, wird als Öffnungsdifferenzdruck des Saugventils 36 bezeichnet.The pump piston 26 has on its the valve member 76 end facing a reduced diameter extension 82 on, at the transition from the full diameter of the Pump piston 26, on which it is in the cylinder bore 24 an annular shoulder 84 for the extension 82 is formed, on which the closing spring 80 is supported. The Closing spring 80 surrounds extension 82 and carrier part 78 is then arranged on the extension 82. If the pump piston 26 is at its top dead center, the is the stroke position in which the pump piston 26 is closest is arranged towards the housing part 70, so between the Extension 82 of the pump piston 26 and the carrier part 78 Distance in the direction of the longitudinal axis 27 of the pump piston 26 present when the valve member 76 is in its Is in the closed position in which it is on the valve seat 74 is applied. It can be provided that the front end of the Extension 82 of the pump piston 26 a stop Limiting the opening movement of the valve member 76 forms by the carrier part 78 coming to rest on the extension 82. If the pump piston 26 as shown in FIG is at its top dead center, the closing spring 80 of the suction valve 36 highly compressed and exercises accordingly a high force on the valve member 76 with which this is pressed against the valve seat 74. The one through the Closing spring 80 and by the in the working space 34th prevailing pressure generated force on the valve member 76th acts on the pressure prevailing in the inlet channel 72 the valve member 76 generates force in the opening direction opposite. If the prevailing in the inlet channel 72 Pressure on the valve member 76 generated force is greater than by the closing spring 80 and in the working space 34 prevailing pressure on the valve member 76 force, so the valve member 76 moves against the force of the Closing spring 80 in the opening direction and gives the mouth of the Inlet channel 72 in the work space 34 free. The pressure at which the valve member 76 moves in the opening direction referred to as the opening differential pressure of the suction valve 36.

Beim Saughub bewegt sich der Pumpenkolben 26 von seinem oberen Totpunkt gemäß Figur 2 zu seinem unteren Totpunkt gemäß Figur 3. Beim Saughub des Pumpenkolbens 26 wird die Schließfeder 80 zunehmend entspannt, so daß diese eine geringere Kraft in Schließrichtung auf das Ventilglied 76 bewirkt und entsprechend der Öffnungsdifferenzdruck des Saugventils 36 geringer wird. Wenn sich der Pumpenkolben 26 zu Beginn des Saughubs in seinem oberen Totpunkt befindet, so ist der Öffnungsdifferenzdruck des Saugventils 36 am höchsten und wird nachfolgend als maximaler Öffnungsdifferenzdruck bezeichnet. Mit zunehmendem Saughub des Pumpenkolbens 26 nimmt der Öffnungsdifferenzdruck ab, wobei sich in einem Bereich des mittleren Saughubs, das ist eine mittlere Hubstellung des Pumpenkolbens 26 zwischen dessen oberem Totpunkt und dessen unterem Totpunkt, ein mittlerer Öffnungsdifferenzdruck des Saugventils 36 ergibt. Wenn sich der Pumpenkolben 26 in seinem unteren Totpunkt befindet, so ist der Öffnungsdifferenzdruck des Saugventils 36 am geringsten und wird nachfolgend als minimaler Öffnungsdifferenzdruck bezeichnet. Es ist vorgesehen, daß der minimale Öffnungsdifferenzdruck des Saugventils 36 weniger als 0,9 bar, vorzugsweise höchstens 0,8 bar beträgt. Der mittlere Öffnungsdifferenzdruck und der maximale Öffnungsdifferenzdruck des Saugventils 36 sind dann abhängig von der Federrate c der Schließfeder 80, das ist die Änderung der durch diese erzeugten Kraft bezogen auf den Federweg, und vom Hub des Pumpenkolbens 26 zwischen dessen oberem und unterem Totpunkt. Die Federrate c der Schließfeder 80 kann einen kleinen Wert aufweisen, wobei sich die durch die Schließfeder 80 ausgeübte Kraft auf das Ventilglied 76 jedoch über den relativ großen Saughub des Pumpenkolbens 26 wesentlich ändert. Der mittlere Öffnungsdifferenzdruck des Saugventils 36 ist größer als 0,9 bar. Das Verhältnis zwischen dem mittleren Öffnungsdifferenzdruck und dem minimalen Öffnungsdifferenzdruck des Saugventils 36 ist größer als 1 und beträgt höchstens etwa 10.During the suction stroke, the pump piston 26 moves from its top dead center according to Figure 2 to its bottom dead center according to Figure 3. During the suction stroke of the pump piston 26, the Closing spring 80 increasingly relaxed, so that this one less force in the closing direction on the valve member 76 causes and according to the opening differential pressure of the Suction valve 36 is lower. If the pump piston 26 is at its top dead center at the start of the suction stroke, so is the opening differential pressure of the suction valve 36 am highest and is subsequently called the maximum Opening differential pressure called. With increasing suction stroke of the pump piston 26, the opening differential pressure decreases, being in an area of the middle suction stroke that is a middle stroke position of the pump piston 26 between its top dead center and its bottom dead center average opening differential pressure of the suction valve 36 results. When the pump piston 26 is at its bottom dead center is the opening differential pressure of the suction valve 36 least and is subsequently considered to be the minimum Opening differential pressure called. It is provided that the minimum opening differential pressure of the suction valve 36 is less than 0.9 bar, preferably at most 0.8 bar. The mean opening differential pressure and the maximum Opening differential pressure of the suction valve 36 are then dependent from the spring rate c of the closing spring 80, that is the Change in the force generated by this in relation to the Travel, and from the stroke of the pump piston 26 between the top and bottom dead center. The spring rate c the Closing spring 80 can have a small value, whereby the force exerted by the closing spring 80 on the Valve member 76, however, over the relatively large suction stroke of the Pump piston 26 changes significantly. The middle one Opening differential pressure of the suction valve 36 is greater than 0.9 bar. The ratio between the middle Opening differential pressure and the minimum Opening differential pressure of suction valve 36 is greater than 1 and is at most about 10.

Dadurch, daß sich der Öffnungsdifferenzdruck des Saugventils 36 während des Saughubs des Pumpenkolbens 26 verringert, wird ein sicheres Öffnen des Saugventils 36 auch bei geringem Druck im Kraftstoffzulaufkanal 72 infolge eines durch die Kraftstoffzumeßeinrichtung 60 eingestellten kleinen Druchflußquerschnitts von der Förderpumpe 10 her erreicht. Es wird hierbei auch sichergestellt, daß die Saugventile 36 sämtlicher Pumpenelemente 22 der Hochdruckpumpe 18 gleichmäßig öffnen und somit eine gleichmäßige Befüllung der Arbeitsräume 34 sämtlicher Pumpenelemente 22 und somit eine gleichförmige Kraftstofförderung durch die Hochdruckpumpe 18 erreicht. Durch Verwendung einer Schließfeder 80 mit geringer Federrate c kann der Einfluß von Toleranzen der Bauteile der Hochdruckpumpe 18 auf den Öffnungsdruck verringert werden und dadurch ebenfalls eine Verbesserung der gleichmäßigen Kraftstofförderung durch sämtliche Pumpenelemente 22 erreicht werden. Außerdem kann durch einen geringen mittleren und minimalen Öffnungsdifferenzdruck des Saugventils 36 die Befüllung des Arbeitsraums 34 verbessert werden, da die beiden füllungsentscheidenden Parameter, nämlich die füllungswirksame Druckdifferenz vor und nach dem Saugventil 36 und die Öffnungsdauer des Saugventils 36, bei geringem Öffnungsdifferenzdruck des Saugventils 36 groß sind. Andererseits kann bei vorgegebener Füllung des Arbeitsraums 34 der Pumpenelemente 22 eine Förderpumpe 10 mit geringerer Förderleistung und entsprechend schwächer dimensioniertem Antrieb verwendet werden, die dadurch kostengünstiger ist. Dadurch, daß mittels der Kraftstoffzumeßeinrichtung 60 der Druchflußquerschnitt von der Förderpumpe 10 her vollständig verschließbar ist, ist auch bei geringem Öffnungsdifferenzdruck des Saugventils 36 eine Nullförderung der Hochdruckpumpe 18 sichergestellt.The fact that the opening differential pressure of the suction valve 36 reduced during the suction stroke of the pump piston 26, will also open the suction valve 36 safely low pressure in the fuel supply channel 72 due to a set by the fuel metering device 60 small flow cross section from the feed pump 10 ago reached. It is also ensured that the Suction valves 36 of all pump elements 22 Open high pressure pump 18 evenly and thus one uniform filling of the working spaces 34 all Pump elements 22 and thus a uniform one Fuel delivery achieved by the high pressure pump 18. By using a closing spring 80 with less Spring rate c can influence the tolerances of the components of the High pressure pump 18 can be reduced to the opening pressure and thereby also an improvement in the uniform Fuel delivery through all pump elements 22 can be achieved. In addition, by a small mean and minimum opening differential pressure of the Suction valve 36 improves the filling of the working space 34 because the two filling parameters, namely the filling pressure difference before and after Suction valve 36 and the opening time of the suction valve 36, at low opening differential pressure of the suction valve 36 large are. On the other hand, given the filling of the Working space 34 of the pump elements 22, a feed pump 10 with lower output and correspondingly weaker dimensioned drive can be used is cheaper. The fact that by means of Fuel metering device 60 the flow cross section of the feed pump 10 is completely closable, is even with a low opening differential pressure of the suction valve 36 zero delivery of the high pressure pump 18 is ensured.

Claims (6)

Kraftstoffeinspritzeinrichtung für eine Brennkraftmaschine mit einer Hochdruckpumpe (18), durch die Kraftstoff unter Hochdruck in einen Speicher (32) gefördert wird, mit dem an den Zylindern der Brennkraftmaschine angeordnete Injektoren (40) verbunden sind, mit einer Förderpumpe (10), durch die Kraftstoff aus einem Vorratsbehälter (12) zur Hochdruckpumpe (18) gefördert wird, wobei die Hochdruckpumpe (18) wenigstens ein Pumpenelement (22) aufweist mit einem einen Arbeitsraum (34) begrenzenden, in einer Hubbewegung angetriebenen Pumpenkolben (26), und wobei der Arbeitsraum (34) eine Verbindung mit der Druckseite der Förderpumpe (10) aufweist, in der ein zum Arbeitsraum (34) hin öffnendes Saugventil (36) angeordnet ist, durch das beim Saughub des Pumpenkolbens (26) Kraftstoff in den Arbeitsraum (34) einströmt, wobei das Saugventil (36) ein durch eine Schließfeder (80) in einer Schließrichtung beaufschlagtes Ventilglied (76) aufweist, wobei sich die Schließfeder (80) zumindest mittelbar am Pumpenkolben (26) abstützt und wobei mit zunehmendem Saughub des Pumpenkolbens (26) die durch die Schließfeder (80) auf das Ventilglied (76) ausgeübte Schließkraft geringer wird, dadurch gekennzeichnet, daß ein minimaler Öffnungsdifferenzdruck des Saugventils (36) weniger als 0,9 bar beträgt. Fuel injection device for an internal combustion engine with a high-pressure pump (18), through which fuel is delivered under high pressure into a memory (32), to which injectors (40) arranged on the cylinders of the internal combustion engine are connected, with a feed pump (10), through which fuel is conveyed from a storage container (12) to the high-pressure pump (18), the high-pressure pump (18) having at least one pump element (22) with a pump piston (26) which delimits a working space (34) and is driven in a lifting movement, and wherein 34) has a connection to the pressure side of the feed pump (10), in which a suction valve (36) opening towards the working chamber (34) is arranged, through which fuel flows into the working chamber (34) during the suction stroke of the pump piston (26), whereby the suction valve (36) has a valve member (76) acted upon by a closing spring (80) in a closing direction, the closing spring (80) being at least m supported directly on the pump piston (26) and, with increasing suction stroke of the pump piston (26), the closing force exerted by the closing spring (80) on the valve member (76) becomes lower, characterized in that a minimum opening differential pressure of the suction valve (36) is less than 0 , 9 bar. Kraftstoffeinspritzeinrichtung nach Anspruch 1, dadurch gekennzeichnet, daß der minimale Öffnungsdifferenzdruck des Saugventils (36) höchstens 0,8 bar beträgt.Fuel injection device according to Claim 1, characterized in that the minimum opening differential pressure of the suction valve (36) is at most 0.8 bar. Kraftstoffeinspritzeinrichtung nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß ein mittlerer Öffnungsdifferenzdruck des Saugventils (36) in einer Zwischenstellung des Pumpenkolbens (26) im Bereich des halben Saughubs des Pumpenkolbens (26) wenigstens 0,9 bar beträgt.Fuel injection device according to Claim 1 or 2, characterized in that an average opening differential pressure of the suction valve (36) in an intermediate position of the pump piston (26) in the region of half the suction stroke of the pump piston (26) is at least 0.9 bar. Kraftstoffeinspritzeinrichtung nach Anspruch 3, dadurch gekennzeichnet, daß das Verhältnis von mittlerem Öffnungsdifferenzdruck zu minimalem Öffnungsdifferenzdruck des Saugventils (36) größer als 1 ist und höchstens 10 beträgt.Fuel injection device according to Claim 3, characterized in that the ratio of the mean opening differential pressure to the minimum opening differential pressure of the suction valve (36) is greater than 1 and is at most 10. Kraftstoffeinspritzeinrichtung nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß zwischen der Förderpumpe (10) und dem Saugventil (36) eine Kraftstoffzumeßeinrichtung (60) angeordnet ist, durch die ein Durchflußquerschnitt für den zum Saugventil (36) fließenden Kraftstoff eingestellt wird und durch die der Druchflußquerschnitt vollständig verschließbar ist.Fuel injection device according to one of Claims 1 to 4, characterized in that a fuel metering device (60) is arranged between the feed pump (10) and the suction valve (36), through which a flow cross-section for the fuel flowing to the suction valve (36) is set and through which the flow cross section is completely closable. Kraftstoffeinspritzeinrichtung nach Anspruch 5, dadurch gekennzeichnet, daß durch die Kraftstoffzumeßeinrichtung (60) der Durchflußquerschnitt derart eingestellt wird, daß durch die Hochdruckpumpe (18) eine Kraftstoffmenge in den Speicher (32) gefördert wird, die erforderlich ist, um im Speicher (32) einen vorgegebenen Druck aufrechtzuerhalten.Fuel injection device according to Claim 5, characterized in that the flow cross-section is set by the fuel metering device (60) in such a way that the high-pressure pump (18) conveys a quantity of fuel into the accumulator (32) which is necessary in order to have a maintain predetermined pressure.
EP03004643.7A 2002-04-23 2003-03-03 Fuel injection system for internal combustion engine Expired - Lifetime EP1357283B1 (en)

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JP2003314409A (en) 2003-11-06
EP1357283B1 (en) 2014-07-02
JP4395319B2 (en) 2010-01-06
EP1357283A3 (en) 2004-09-22
US20030213471A1 (en) 2003-11-20
DE10218022A1 (en) 2003-11-06
US6959694B2 (en) 2005-11-01

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