EP0745184B1 - Process for reducing the fuel pressure in a fuel injection system - Google Patents

Process for reducing the fuel pressure in a fuel injection system Download PDF

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Publication number
EP0745184B1
EP0745184B1 EP95919966A EP95919966A EP0745184B1 EP 0745184 B1 EP0745184 B1 EP 0745184B1 EP 95919966 A EP95919966 A EP 95919966A EP 95919966 A EP95919966 A EP 95919966A EP 0745184 B1 EP0745184 B1 EP 0745184B1
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EP
European Patent Office
Prior art keywords
pressure
valve
injection
space
storage space
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP95919966A
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German (de)
French (fr)
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EP0745184A1 (en
Inventor
Eugen Drummer
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Robert Bosch GmbH
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Robert Bosch GmbH
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M47/00—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
    • F02M47/02—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure of accumulator-injector type, i.e. having fuel pressure of accumulator tending to open, and fuel pressure in other chamber tending to close, injection valves and having means for periodically releasing that closing pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/38—Controlling fuel injection of the high pressure type
    • F02D41/3809—Common rail control systems
    • F02D41/3836—Controlling the fuel pressure
    • F02D41/3863—Controlling the fuel pressure by controlling the flow out of the common rail, e.g. using pressure relief valves
    • F02D41/3872—Controlling the fuel pressure by controlling the flow out of the common rail, e.g. using pressure relief valves characterised by leakage flow in injectors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/04—Introducing corrections for particular operating conditions
    • F02D41/042—Introducing corrections for particular operating conditions for stopping the engine
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/38—Controlling fuel injection of the high pressure type
    • F02D41/3809—Common rail control systems
    • F02D41/3827—Common rail control systems for diesel engines
    • 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
    • F02M47/00—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
    • F02M47/02—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure of accumulator-injector type, i.e. having fuel pressure of accumulator tending to open, and fuel pressure in other chamber tending to close, injection valves and having means for periodically releasing that closing pressure
    • F02M47/027—Electrically actuated valves draining the chamber to release the closing pressure
    • 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
    • F02M55/00—Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump F02M37/00
    • F02M55/02—Conduits between injection pumps and injectors, e.g. conduits between pump and common-rail or conduits between common-rail and injectors
    • 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
    • F02M63/0003—Fuel-injection apparatus having a cyclically-operated valve for connecting a pressure source, e.g. constant pressure pump or accumulator, to an injection valve held closed mechanically, e.g. by springs, and automatically opened by fuel pressure
    • F02M63/0007—Fuel-injection apparatus having a cyclically-operated valve for connecting a pressure source, e.g. constant pressure pump or accumulator, to an injection valve held closed mechanically, e.g. by springs, and automatically opened by fuel pressure using electrically actuated valves
    • 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
    • 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
    • F02M69/00—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel
    • F02M69/46—Details, component parts or accessories not provided for in, or of interest apart from, the apparatus covered by groups F02M69/02 - F02M69/44
    • F02M69/462—Arrangement of fuel conduits, e.g. with valves for maintaining pressure in the pipes after the engine being shut-down
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2250/00—Engine control related to specific problems or objectives
    • F02D2250/31—Control of the fuel pressure

Definitions

  • the invention is based on a fuel injection device for internal combustion engines according to the preamble of the patent claim 1.
  • a high pressure feed pump fills the fuel injector a high pressure accumulator with fuel from a storage tank.
  • Lead from the high-pressure accumulator (common rail) Pressure lines to the individual, in the combustion chamber too supplying internal combustion engine projecting injection valves from that in the known device via a first Channel directly into one, the valve member of the injection valve in the opening direction Pressure chamber and a second channel with one that Valve member acting in the closing direction second, one Control room forming pressure chamber are connectable.
  • the second channel is a 3/2-way control valve used that the control chamber on the valve member with that of High pressure accumulator outgoing pressure line or one Relief line connects to the storage tank.
  • the 3/2-way control valve is operated by a solenoid valve actuated by one, different operating parameters of the Internal combustion engine manufacturing electronic control unit is controlled.
  • the injection valve is connected by the Control room with the high pressure accumulator kept closed, why the pressure application surface of the Valve member is made larger than that in the first Pressure application area protruding in the opening direction.
  • the control valve connects the control room to the relief line, so that the high pressure in the control room over this relieved in the storage tank, being used to control the Injection course also a throttle in the relief line is provided.
  • the pressure reduction in the control room causes due to the pressure in the first with the high pressure accumulator connected pressure chamber an opening stroke movement of the valve member, so that an injection cross section at the injection valve is controlled via which the fuel under high Pressure injected into the combustion chamber of the internal combustion engine becomes.
  • the injection is made by switching the Control valve and connecting the control room with the High-pressure accumulator ended, in the course of which the High fuel pressure builds up in the control room, so that Valve member is pushed back into its closed position.
  • the known fuel injection device has the disadvantage that the high fuel pressure too after switching off the internal combustion engine for a long time in the system remains what maintenance or repair work very makes dangerous, so that the known system the usual Security requirements are not enough.
  • the method according to the invention for reducing the fuel pressure in a fuel injector with the characterizing features of claim 1 on the other hand the advantage that it is possible to High pressure in the high pressure accumulator and the associated with it System after switching off the internal combustion engine on to lower the low, harmless pressure level. This takes place by means of the components already present on the system, so that unlike other solutions no additional pressure valve and no further line required be what in particular the manufacturing costs and thus the Injector cost reduced.
  • the pressure relief takes place in an advantageous manner according to the claims 4-6 via the control valve and the pressure chambers of the injection valve into the storage tank, which is why only one more Control possibility of the actuating the control valve Solenoid valve on the electronic control unit after switching off the internal combustion engine is to be provided.
  • the control of the Control valve is then so short that the injection valve the one necessary for lifting the valve member Can not build pressure. This takes place depending on the design Build up either by briefly relieving the pressure on the Control room on the valve member or by briefly applying pressure of the valve member in the opening direction acting pressure chamber, to which a new filling of the Control room or a pressure relief of the pressure room connect, so that the high pressure continuously over the Relief line can be dismantled in the storage tank.
  • the electronic control unit controls this Solenoid valve with a high frequency, preferably through a two-part control (pre-injection, main injection) and achieved by assuming a high engine speed is, with all the injection valves of the internal combustion engine in this relief process are included.
  • the control the individual control valves are carried out in succession, preferably in the order of the firing order of the individual cylinders.
  • FIG. 1 shows a first embodiment in a schematic representation, in which the injection valve two opposite to the valve member of the injector has acting pressure rooms, a first of which Pressure chamber constantly connected to and from the high pressure system which a second, the stroke movement of the valve member controlling pressure chamber by means of a 3/2-way control valve the high pressure system or a storage tank can be connected
  • 2 shows a second embodiment analogous to the figure 1, in which the second pressure chamber by means of a 2/2-way control valve can be connected to the storage tank
  • the fuel injector promotes one pressure-controllable high-pressure feed pump 1 fuel from one Storage tank 5 with high pressure via a delivery line 3 in a high-pressure storage space 7 (common rail), of which several corresponding to the number of injection points Pressure lines 9 to the individual, in the combustion chamber to supplying internal combustion engine projecting injection valves 11 lead away.
  • a high-pressure storage space 7 common rail
  • the injection valve 11 has a guide bore 13 axially displaceable piston-shaped valve member 15, with a conical valve sealing surface 17 at one end, with which it has a valve seat on the housing 21 of the injection valve 11 cooperates, being known in Downstream injection openings, not shown Connect to valve seat 19.
  • the valve member 15 protrudes into two inside the guide bore 13 formed pressure chambers, a first of which the valve member in the opening direction acting pressure chamber 23 by a Cross-sectional reduction of the valve member 15 is formed.
  • This first pressure chamber 23 is via a pressure channel 25 in the pressure line 9 opens continuously with the high-pressure storage space 7 connected and over in a known manner an annular gap between the valve member 15 and the Guide bore 13 up to the valve seat 19.
  • valve member 15 projects through against one another the high-pressure sealed spring chamber 26, in one that acts on the valve member 15 in the closing direction Valve spring 28 is arranged.
  • valve member At its end facing away from the valve seat 19, the valve member has a cross-sectional expansion, the valve seat facing away End face 27 a second, a control chamber 29 forming, acting on the valve member 15 in the closing direction Pressure space limited by a connecting channel 29 is connected to a 3/2-way control valve 31, which Control room 29 with a throttle 33 included Relief line 35 in the serving as a relief space Storage tank 5 or with the pressure line 9 from the high pressure storage space 7 connects, analogously also a relief line is possible without throttle.
  • the 3/2-way control valve is actuated by an electromagnet 37, the one is controlled electronic control unit 39, the in turn various sensors supplied to it via sensors 41 Operating parameters (speed, accelerator pedal position, etc.) of the supplying internal combustion engine processed. To do it too detect the pressure within the high pressure system and To be able to edit is also a pressure sensor 43 in the High-pressure storage space 7 used.
  • the fuel injector operates during operation the internal combustion engine in a known manner, the High-pressure feed pump 1 first the high-pressure storage space 7 filled with fuel under high pressure. This High fuel pressure builds up via the pressure lines 9 the individual injection valves 11 and acted upon there the first pressure chamber 23.
  • the valve member 15 is thereby by the force of the valve spring 28 and the pressure in Control chamber 29, through the 3/2-way control valve 31 with the Pressure line 9 is connected in the closed state of the Injector 11 held in contact with the valve seat 19, wherein the end face 27 of the valve member projecting into the control chamber 29 15 is larger than the first pressure chamber 23 limiting ring shoulder.
  • the end of the injection process is by switching again of the 3/2-way control valve 31 initiated the Control chamber 29 connects to the pressure line 9 again, see above that in the control chamber 29 again, the valve member 15 builds up its valve seat 19 moving back high pressure.
  • the explanation of the pressure reduction according to the invention in High-pressure storage space 7 and in the pressure lines 9 after parking the internal combustion engine is based on that in the figure 4 shown diagram, in which the duration of the Control signal of the electromagnet 37 (MV), the needle stroke (NH) of the 3/2-way control valve actuated by the electromagnet 37 31 and the pressure curve ( ⁇ P) in the high-pressure storage space 7 are plotted over time (t).
  • the control unit 39 adjusts the electromagnet 37 the shutdown of the internal combustion engine to be supplied with high Frequency, e.g. through a shared control (analog pre and main injection) can be achieved.
  • NH ballistic needle stroke
  • the process of reducing pressure is carried out by means of the Pressure sensor 43 monitored by the control unit 39, which in Dependence on the pressure in the high-pressure storage space 7 Pressure adjusts the control duration of the 3/2-way control valves 31.
  • the electromagnets 37 become shorter at high pressure controlled than at low, so that there is an optimal Drain time while safely avoiding one Can achieve fuel injection.
  • the second embodiment shown in Figure 2 a fuel injector for performing the The method according to the invention differs for the first In the embodiment shown in Figure 1 only in the type of connection of the control chamber 29 to the injection valve 11 with the pressure line 9 and the relief line 35 and the structure of the control valve that there as a 2/2-way control valve 45 is formed and the connection of the Control room 29 to the relief line 35 up or controls.
  • the control chamber 29 is a first one Throttle point 47 contained connecting line 49 with the Pressure line 9 connected.
  • In the connecting channel 30 to 2/2-way control valve 45 is a second throttle point 51 used, on the design of the discharge process of Fuel from the control room 29 in the storage tank 5 and thus the opening stroke movement of the valve member 15 adjustable is.
  • the second embodiment works analogously to the first, whereby during the operation of the internal combustion engine as a result opening the connection control room 29 relief line 35 by the 2/2-way control valve controlled by the electromagnet 37 45 the lifting of the valve member 15 from the valve seat 19 and thus the injection process takes place.
  • the pressure relief of the high pressure storage space 7 after switching off the internal combustion engine takes place as in the first Embodiment described by the short-term Open the connection between control room 29 and relief line 35, so that the constant refilling of the control room 29 from the high-pressure storage space 7 whose pressure is reduced can be.
  • the pressure relief of the Control room 29 only so short and to such a small extent, that there is no injection at the injection valves 11.
  • the third embodiment shown in Figure 3 has only one pressure chamber acting on the valve member 15 323 on the injection valve 11, via the 3/2-way control valve 31 controlled connection to the pressure line 9 of the high-pressure storage space 7 in a known manner Opening stroke of the valve member 15 against the force of the valve spring 28 and thus the opening of the injection valve 11 takes place, while on the connection of the pressure chamber 323 with the relief line 35 the pressure relief and in a row the injection valve 11 is closed.
  • Pressure valve a certain stand pressure in the pressure chamber 323.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Fuel-Injection Apparatus (AREA)

Abstract

A process for reducing the fuel pressure in a fuel injection system after the internal combustion engine supplied has been stopped, in which the high fuel pressure built up by a high-pressure feed pump (1) in a high-pressure storage chamber (common rail) (7) is discharge into the fuel tank (5) via the control valves (31) needed to control the injection process at the injection valves (11) connected to the high-pressure storage chamber (7). To this end the control valves (31) are operated in such a way that they connect pressure chamber (29) in the injection valve (11) briefly with the high-pressure storage chamber (7) or the fuel tank (5) in such a way that the pressure applied to the valve member (15) of the injection valve (11) in the opening direction remains below an opening pressure of the injection value (11), and said control valve (31, 323) operating process is repeated until a desired pressure is attained in the high-pressure storage chamber (7).

Description

Stand der TechnikState of the art

Die Erfindung geht von einer Kraftstoffeinspritzeinrichtung für Brennkraftmaschinen nach der Gattung des Patentanspruchs 1. Bei einer derartigen aus der Fachzeitschrift ATZ/MTZ Sonderheft Motor und Umwelt 1992, Seiten 28-30 bekannten Kraftstoffeinspritzeinrichtung füllt eine Hochdruckförderpumpe einen Hochdruckspeicher mit Kraftstoff aus einem Vorratstank. Vom Hochdruckspeicher (Common-Rail) führen Druckleitungen zu den einzelnen, in den Brennraum der zu versorgenden Brennkraftmaschine ragenden Einspritzventilen ab, die dabei bei der bekannten Einrichtung über einen ersten Kanal direkt in einen, das Ventilglied des Einspritzventils in Öffnungsrichtung beaufschlagenden ersten Druckraum münden und über einen zweiten Kanal mit einem, das Ventilglied in Schließrichtung beaufschlagenden zweiten, einen Steuerraum bildenden Druckraum verbindbar sind. In diesen zweiten Kanal ist dabei ein 3/2- Wegesteuerventil eingesetzt, daß den Steuerraum am Ventilglied mit der vom Hochdruckspeicher abgehenden Druckleitung oder einer Entlastungsleitung in den Vorratstank verbindet.The invention is based on a fuel injection device for internal combustion engines according to the preamble of the patent claim 1. In such a from the ATZ / MTZ special issue Motor und Umwelt 1992, pages 28-30 known A high pressure feed pump fills the fuel injector a high pressure accumulator with fuel from a storage tank. Lead from the high-pressure accumulator (common rail) Pressure lines to the individual, in the combustion chamber too supplying internal combustion engine projecting injection valves from that in the known device via a first Channel directly into one, the valve member of the injection valve in the opening direction Pressure chamber and a second channel with one that Valve member acting in the closing direction second, one Control room forming pressure chamber are connectable. In these the second channel is a 3/2-way control valve used that the control chamber on the valve member with that of High pressure accumulator outgoing pressure line or one Relief line connects to the storage tank.

Das 3/2-Wegesteuerventil wird dabei von einem Magnetventil betätigt, das von einem, verschiedene Betriebsparameter der Brennkraftmaschine verarbeitenden elektronischen Steuergerät angesteuert wird.The 3/2-way control valve is operated by a solenoid valve actuated by one, different operating parameters of the Internal combustion engine manufacturing electronic control unit is controlled.

Das Einspritzventil wird dabei durch die Verbindung des Steuerraumes mit dem Hochdruckspeicher geschlossen gehalten, wozu die in den Steuerraum ragende Druckangriffsfläche des Ventilgliedes größer ausgeführt ist, als die in den ersten Druckraum ragende Druckangriffsfläche in Öffnungsrichtung. The injection valve is connected by the Control room with the high pressure accumulator kept closed, why the pressure application surface of the Valve member is made larger than that in the first Pressure application area protruding in the opening direction.

Soll eine Einspritzung am Einspritzventil erfolgen, verbindet das Steuerventil den Steuerraum mit der Entlastungsleitung, so daß sich der Hochdruck im Steuerraum über diese in den Vorratstank entlastet, wobei zur Steuerung des Einspritzverlaufs zudem eine Drossel in der Entlastungsleitung vorgesehen ist. Der Druckabbau im Steuerraum bewirkt infolge des Drucks im ersten ständig mit dem Hochdruckspeicher verbundenen Druckraum eine Öffnungshubbewegung des Ventilgliedes, so daß ein Einspritzquerschnitt am Einspritzventil aufgesteuert wird, über den der Kraftstoff unter hohem Druck in den Brennraum der Brennkraftmaschine eingespritzt wird. Die Einspritzung wird durch das erneute Umschalten des Steuerventils und dem Verbinden des Steuerraumes mit dem Hochdruckspeicher beendet, in dessen Verlauf sich erneut der Kraftstoffhochdruck im Steuerraum aufbaut, so daß das Ventilglied in seine Schließlage zurückverschoben wird. Dabei weist die bekannte Kraftstoffeinspritzeinrichtung jedoch den Nachteil auf, daß der hohe Kraftstoffdruck auch nach Abstellen der Brennkraftmaschine noch lange Zeit im System verbleibt, was Wartungs- bzw. Reparaturarbeiten sehr gefährlich macht, so daß das bekannte System den üblichen Sicherheitsanforderungen nicht genügt.If the injection valve is to be injected, the control valve connects the control room to the relief line, so that the high pressure in the control room over this relieved in the storage tank, being used to control the Injection course also a throttle in the relief line is provided. The pressure reduction in the control room causes due to the pressure in the first with the high pressure accumulator connected pressure chamber an opening stroke movement of the valve member, so that an injection cross section at the injection valve is controlled via which the fuel under high Pressure injected into the combustion chamber of the internal combustion engine becomes. The injection is made by switching the Control valve and connecting the control room with the High-pressure accumulator ended, in the course of which the High fuel pressure builds up in the control room, so that Valve member is pushed back into its closed position. However, the known fuel injection device has the disadvantage that the high fuel pressure too after switching off the internal combustion engine for a long time in the system remains what maintenance or repair work very makes dangerous, so that the known system the usual Security requirements are not enough.

Vorteile der ErfindungAdvantages of the invention

Das erfindungsgemäße Verfahren zur Reduzierung des Kraftstoffdruckes in einer Kraftstoffeinspritzeinrichtung mit den kennzeichnenden Merkmalen des Patentanspruchs 1 weist demgegenüber den Vorteil auf, daß es möglich ist, den Hochdruck im Hochdruckspeicher und dem mit diesem verbundenen System nach dem Abstellen der Brennkraftmaschine auf ein geringes, ungefährliches Druckniveau abzusenken. Dies erfolgt dabei mittels der am System bereits vorhandenen Bauteile, so daß im Gegensatz zu anderen Lösungen kein zusätzliches Druckventil und keine weitere Leitung benötigt werden, was insbesondere den Fertigungsaufwand und somit die Kosten der Einspritzeinrichtung verringert.The method according to the invention for reducing the fuel pressure in a fuel injector with the characterizing features of claim 1 on the other hand the advantage that it is possible to High pressure in the high pressure accumulator and the associated with it System after switching off the internal combustion engine on to lower the low, harmless pressure level. This takes place by means of the components already present on the system, so that unlike other solutions no additional pressure valve and no further line required be what in particular the manufacturing costs and thus the Injector cost reduced.

Die Druckentlastung erfolgt dabei in vorteilhafter Weise gemäß dem Patentansprüchen 4-6 über das Steuerventil und die Druckräume des Einspritzventils in den Vorratstank, wozu lediglich eine weitere Ansteuermöglichkeit des das Steuerventil betätigenden Magnetventils am elektronischen Steuergerät nach Abstellen der Brennkraftmaschine vorzusehen ist. Die Ansteuerung des Steuerventils erfolgt dann so kurz, daß sich am Einspritzventil der für das Abheben des Ventilgliedes notwendige Druck nicht aufbauen kann. Dies erfolgt je nach konstruktivem Aufbau entweder durch das kurzzeitige Druckentlasten des Steuerraums am Ventilglied oder durch das kurze Druckbeaufschlagen des in Öffnungsrichtung auf das Ventilglied wirkenden Druckraumes, an das sich ein erneutes Befüllen des Steuerraumes bzw. ein Druckentlasten des Druckraumes anschließen, so daß der Hochdruck kontinuierlich über die Entlastungsleitung in den Vorratstank abgebaut werden kann. Um dabei ein möglichst kurzes Ansteuern des Steuerventils zu erreichen, steuert das elektronische Steuergerät das Magnetventil mit einer hohen Frequenz an, die vorzugsweise durch eine zweiteilige Ansteuerung (Vor-, Haupteinspritzung) und durch die Annahme einer hohen Motordrehzahl erreicht wird, wobei alle Einspritzventile der Brennkraftmaschine in diesen Entlastungsvorgang einbezogen sind. Die Ansteuerung der einzelnen Steuerventile erfolgt dabei nacheinander, vorzugsweise in der Reihenfolge der Zündfolge der einzelnen Zylinder.The pressure relief takes place in an advantageous manner according to the claims 4-6 via the control valve and the pressure chambers of the injection valve into the storage tank, which is why only one more Control possibility of the actuating the control valve Solenoid valve on the electronic control unit after switching off the internal combustion engine is to be provided. The control of the Control valve is then so short that the injection valve the one necessary for lifting the valve member Can not build pressure. This takes place depending on the design Build up either by briefly relieving the pressure on the Control room on the valve member or by briefly applying pressure of the valve member in the opening direction acting pressure chamber, to which a new filling of the Control room or a pressure relief of the pressure room connect, so that the high pressure continuously over the Relief line can be dismantled in the storage tank. In order to control the control valve as briefly as possible the electronic control unit controls this Solenoid valve with a high frequency, preferably through a two-part control (pre-injection, main injection) and achieved by assuming a high engine speed is, with all the injection valves of the internal combustion engine in this relief process are included. The control the individual control valves are carried out in succession, preferably in the order of the firing order of the individual cylinders.

Um dabei zu gewährleisten daß die Ansteuerdauer nur so kurz gewählt wird, daß Kraftstoff aus dem Leitungssystem entweichen kann, jedoch keine Einspritzung erfolgt, wird während des Druckentlastungsvorganges der Druck im Hochdrucksystem mittels wenigstens eines Drucksensors überwacht, der mit dem elektronischen Steuergerät gekoppelt ist, das die Ansteuerdauer der die Steuerventile betätigenden Magnetventile an den vorhandenen Systemdruck anpaßt. Durch diese Anpassung ist es in vorteilhafter Weise möglich, die Entleerungszeit zu verkürzen, da bei niedrigeren Drücken im System die Ansteuerzeit der Magnetventile bereits verlängert werden kann.In order to ensure that the activation time is only so short is chosen that fuel from the pipe system can escape, but no injection takes place the pressure in the high pressure system during the pressure relief process monitored by means of at least one pressure sensor, which is coupled to the electronic control unit that the control duration of the actuating the control valves Adapts solenoid valves to the existing system pressure. By this adjustment it is possible in an advantageous manner Shorten emptying time, because at lower pressures in System has already extended the activation time of the solenoid valves can be.

Weitere Vorteile und vorteilhafte Ausgestaltungen des Gegenstandes der Erfindung sind der Beschreibung, der Zeichnung und den Ansprüchen entnehmbar.Further advantages and advantageous configurations of the The invention relates to the description of Drawing and the claims can be removed.

Zeichnungdrawing

Drei Ausführungsbeispiele der erfindungsgemäßen Kraftstoffeinspritzeinrichtung zur Durchführung des Verfahrens zur Reduzierung des Kraftstoffdruckes nach Abstellen der zu versorgenden Brennkraftmaschine sind in der Zeichnung dargestellt und werden in der nachfolgenden Beschreibung erläutert.Three embodiments of the fuel injection device according to the invention to carry out the reduction process the fuel pressure after turning off the supplying internal combustion engine are in the drawing shown and are explained in the following description.

Es zeigen die Figur 1 ein erstes Ausführungsbeispiel in einer schematischen Darstellung, bei dem das Einspritzventil zwei entgegengesetzt auf das Ventilglied des Einspritzventils wirkende Druckräume aufweist, von denen ein erster Druckraum ständig mit dem Hochdrucksystem verbunden und von denen ein zweiter, die Hubbewegung des Ventilgliedes steuernder Druckraum mittels eines 3/2-Wegesteuerventils mit dem Hochdrucksystem oder einem Vorratstank verbindbar ist, die Figur 2 ein zweites Ausführungsbeispiel analog zur Figur 1, bei dem der zweite Druckraum mittels eines 2/2- Wegesteuerventils mit dem Vorratstank verbindbar ist, die Figur 3 ein drittes Ausführungsbeispiel in schematischer Darstellung, an dem nur ein, das Ventilglied entgegen einer Federkraft in Öffnungsrichtung beaufschlagender Druckraum vorgesehen ist, der mittels eines 3/2-Wegesteuerventils mit dem Hochdrucksystem oder dem Vorratstank verbindbar ist und die Figur 4 ein Diagramm, in dem die Dauer des Ansteuersignals des Magnetventils, die Dauer des Magnetventilnadelhubs und der Druck im System über der Zeit aufgetragen sind.1 shows a first embodiment in a schematic representation, in which the injection valve two opposite to the valve member of the injector has acting pressure rooms, a first of which Pressure chamber constantly connected to and from the high pressure system which a second, the stroke movement of the valve member controlling pressure chamber by means of a 3/2-way control valve the high pressure system or a storage tank can be connected, 2 shows a second embodiment analogous to the figure 1, in which the second pressure chamber by means of a 2/2-way control valve can be connected to the storage tank, FIG. 3 a third embodiment in a schematic representation, on the only one, the valve member against one Pressure chamber acting on the spring force in the opening direction is provided, which by means of a 3/2-way control valve the high pressure system or the storage tank is connectable and 4 shows a diagram in which the duration of the control signal of the solenoid valve, the duration of the solenoid valve needle stroke and the pressure in the system is plotted over time.

Beschreibung der AusführungsbeispieleDescription of the embodiments

Bei dem in der Figur 1 dargestellten ersten Ausführungsbeispiel der Kraftstoffeinspritzeinrichtung fördert eine druckregelbare Hochdruckförderpumpe 1 Kraftstoff aus einem Vorratstank 5 mit hohem Druck über eine Förderleitung 3 in einen Hochdruckspeicherraum 7 (Common Rail), von dem mehrere, der Anzahl der Einspritzstellen entsprechende Druckleitungen 9 zu den einzelnen, in den Brennraum der zu versorgenden Brennkraftmaschine ragenden Einspritzventilen 11 abführen.In the first embodiment shown in Figure 1 the fuel injector promotes one pressure-controllable high-pressure feed pump 1 fuel from one Storage tank 5 with high pressure via a delivery line 3 in a high-pressure storage space 7 (common rail), of which several corresponding to the number of injection points Pressure lines 9 to the individual, in the combustion chamber to supplying internal combustion engine projecting injection valves 11 lead away.

Das Einspritzventil 11 weist ein in einer Führungsbohrung 13 axial verschiebbares kolbenförmiges Ventilglied 15 auf, mit einer konischen Ventildichtfläche 17 an seinem einen Ende, mit der es mit einer Ventilsitzfläche am Gehäuse 21 des Einspritzventils 11 zusammenwirkt, wobei sich in bekannter Weise nicht näher dargestellte Einspritzöffnungen stromabwärts an den Ventilsitz 19 anschließen. Das Ventilglied 15 ragt dabei in zwei innerhalb der Führungsbohrung 13 gebildete Druckräume, von denen ein erster das Ventilglied in Öffnungsrichtung beaufschlagender Druckraum 23 durch eine Querschnittsverringerung des Ventilgliedes 15 gebildet ist. Dieser erste Druckraum 23 ist über einen Druckkanal 25, der in die Druckleitung 9 mündet ständig mit dem Hochdruckspeicherraum 7 verbunden und setzt sich in bekannter Weise über einen Ringspalt zwischen dem Ventilglied 15 und der Führungsbohrung 13 bis an den Ventilsitz 19 fort.The injection valve 11 has a guide bore 13 axially displaceable piston-shaped valve member 15, with a conical valve sealing surface 17 at one end, with which it has a valve seat on the housing 21 of the injection valve 11 cooperates, being known in Downstream injection openings, not shown Connect to valve seat 19. The valve member 15 protrudes into two inside the guide bore 13 formed pressure chambers, a first of which the valve member in the opening direction acting pressure chamber 23 by a Cross-sectional reduction of the valve member 15 is formed. This first pressure chamber 23 is via a pressure channel 25 in the pressure line 9 opens continuously with the high-pressure storage space 7 connected and over in a known manner an annular gap between the valve member 15 and the Guide bore 13 up to the valve seat 19.

Im mittleren Bereich durchragt das Ventilglied 15 einen gegen den Kraftstoffhochdruck abgedichteten Federraum 26, in dem eine das Ventilglied 15 in Schließrichtung beaufschlagende Ventilfeder 28 angeordnet ist. In the middle area, the valve member 15 projects through against one another the high-pressure sealed spring chamber 26, in one that acts on the valve member 15 in the closing direction Valve spring 28 is arranged.

An seinem dem Ventilsitz 19 abgewandten Ende weist das Ventilglied eine Querschnittserweiterung auf, deren ventilsitzabgewandte Stirnfläche 27 einen zweiten, einen Steuerraum 29 bildenden, das Ventilglied 15 in Schließrichtung beaufschlagenden Druckraum begrenzt, der über einen Verbindungskanal 29 an ein 3/2-Wegesteuerventil 31 angeschlossen ist, das den Steuerraum 29 mit einer eine Drossel 33 enthaltenen Entlastungsleitung 35 in den als Entlastungsraum dienenden Vorratstank 5 oder mit der Druckleitung 9 vom Hochdruckspeicherraum 7 verbindet, wobei analog auch eine Entlastungsleitung ohne Drossel möglich ist. Das 3/2-Wegesteuerventil wird dabei von einem Elektromagnet 37 betätigt, der von einem elektronischen Steuergerät 39 angesteuert wird, das seinerseits verschiedene diesem über Sensoren 41 zugeführte Betriebsparameter (Drehzahl, Fahrpedalstellung usw.) der zu versorgenden Brennkraftmaschine verarbeitet. Um dabei auch den Druck innerhalb des Hochdrucksystems erfassen und bearbeiten zu können ist zudem ein Drucksensor 43 in den Hochdruckspeicherraum 7 eingesetzt.At its end facing away from the valve seat 19, the valve member has a cross-sectional expansion, the valve seat facing away End face 27 a second, a control chamber 29 forming, acting on the valve member 15 in the closing direction Pressure space limited by a connecting channel 29 is connected to a 3/2-way control valve 31, which Control room 29 with a throttle 33 included Relief line 35 in the serving as a relief space Storage tank 5 or with the pressure line 9 from the high pressure storage space 7 connects, analogously also a relief line is possible without throttle. The 3/2-way control valve is actuated by an electromagnet 37, the one is controlled electronic control unit 39, the in turn various sensors supplied to it via sensors 41 Operating parameters (speed, accelerator pedal position, etc.) of the supplying internal combustion engine processed. To do it too detect the pressure within the high pressure system and To be able to edit is also a pressure sensor 43 in the High-pressure storage space 7 used.

Die Kraftstoffeinspritzeinrichtung arbeitet während des Betriebs der Brennkraftmaschine in bekannter Weise, wobei die Hochdruckförderpumpe 1 zunächst den Hochdruckspeicherraum 7 mit unter hohem Druck stehenden Kraftstoff befüllt. Dieser Kraftstoffhochdruck setzt sich über die Druckleitungen 9 zu den einzelnen Einspritzventilen 11 fort und beaufschlagt dort den ersten Druckraum 23. Das Ventilglied 15 wird dabei durch die Kraft der Ventilfeder 28 und den Druck im Steuerraum 29, der durch das 3/2-Wegesteuerventil 31 mit der Druckleitung 9 verbunden ist, im geschlossenen Zustand des Einspritzventils 11 in Anlage am Ventilsitz 19 gehalten, wobei die in den Steuerraum 29 ragende Stirnfläche 27 des Ventilgliedes 15 größer ist, als die den ersten Druckraum 23 begrenzende Ringschulter.The fuel injector operates during operation the internal combustion engine in a known manner, the High-pressure feed pump 1 first the high-pressure storage space 7 filled with fuel under high pressure. This High fuel pressure builds up via the pressure lines 9 the individual injection valves 11 and acted upon there the first pressure chamber 23. The valve member 15 is thereby by the force of the valve spring 28 and the pressure in Control chamber 29, through the 3/2-way control valve 31 with the Pressure line 9 is connected in the closed state of the Injector 11 held in contact with the valve seat 19, wherein the end face 27 of the valve member projecting into the control chamber 29 15 is larger than the first pressure chamber 23 limiting ring shoulder.

Soll eine Einspritzung am Einspritzventil 11 erfolgen, wird der Steuerraum 29 vom 3/2-Wegesteuerventil 31 mit der Entlastungsleitung 35 verbunden, so daß sich der Druck im Steuerraum 29 in den Vorratstank 5 entspannt. In Folge übersteigt der in Öffnungsrichtung auf das Ventilglied 15 wirkende Druck im Druckraum 23 die in Schließrichtung auf das Ventilglied 15 wirkenden Kräfte, so daß das Ventilglied 15 vom Ventilsitz 19 abhebt und Kraftstoff über die Einspritzöffnungen eingespritzt wird. Dabei läßt sich über die Dimensionierung der Drossel 33 der Entlastungsvorgang des Steuerraumes 29 und somit die Öffnungshubbewegung des Ventilgliedes 15 beeinflussen.If an injection is to take place at the injection valve 11, the control chamber 29 from the 3/2-way control valve 31 with the Relief line 35 connected so that the pressure in Control room 29 relaxed in the storage tank 5. As a result exceeds the valve member 15 in the opening direction acting pressure in the pressure chamber 23 in the closing direction the valve member 15 acting forces, so that the valve member 15 lifts off the valve seat 19 and fuel over the Injection openings is injected. It can be over the dimensioning of the throttle 33 of the relief process of the control chamber 29 and thus the opening stroke movement of the Influence valve member 15.

Das Ende des Einspritzvorganges wird durch das erneute Umschalten des 3/2-Wegesteuerventils 31 eingeleitet, das den Steuerraum 29 wieder mit der Druckleitung 9 verbindet, so daß sich im Steuerraum 29 erneut ein, das Ventilglied 15 auf seinen Ventilsitz 19 zurückbewegender Hochdruck aufbaut. Die Erläuterung der erfindungsgemäßen Druckreduzierung im Hochdruckspeicherraum 7 und in den Druckleitungen 9 nach Abstellen der Brennkraftmaschine erfolgt anhand des in der Figur 4 dargestellten Diagramms, in dem die Dauer des Ansteuersignals des Elektromagneten 37 (MV), der Nadelhub (NH) des vom Elektromagneten 37 betätigten 3/2-Wegesteuerventils 31 und der Druckverlauf (ΔP) im Hochdruckspeicherraum 7 über der Zeit (t) aufgetragen sind.The end of the injection process is by switching again of the 3/2-way control valve 31 initiated the Control chamber 29 connects to the pressure line 9 again, see above that in the control chamber 29 again, the valve member 15 builds up its valve seat 19 moving back high pressure. The explanation of the pressure reduction according to the invention in High-pressure storage space 7 and in the pressure lines 9 after parking the internal combustion engine is based on that in the figure 4 shown diagram, in which the duration of the Control signal of the electromagnet 37 (MV), the needle stroke (NH) of the 3/2-way control valve actuated by the electromagnet 37 31 and the pressure curve (ΔP) in the high-pressure storage space 7 are plotted over time (t).

Dabei steuert das Steuergerät 39 den Elektromagneten 37 nach dem Abstellen der zu versorgenden Brennkraftmaschine mit hoher Frequenz an, die sich z.B. durch eine geteilte Ansteuerung (analog Vor- und Haupteinspritzung) erreichen läßt. Durch die kurze Bestromung des Elektromagneten 37 führt das von diesem betätigte Ventilglied des 3/2-Wegesteuerventils 31 nur einen ballistischen Nadelhub (NH) aus, so daß das 3/2-Wegesteuerventil 31 die Verbindung zwischen dem Steuerraum 29 und der Entlastungsleitung 35 nicht vollständig öffnet. Auf diese Weise wird gewährleistet, daß der Druck im Steuerraum 29 nicht so weit absinkt, daß der Differenzdruck zum Druckraum 23 ausreicht, das Ventilglied 15 des Einspritzventils 11 von seinem Sitz 19 abheben zu lassen. Nach diesem kurzzeitigen Aufsteuern der Verbindung Steuerraum 29 und Entlastungsleitung 35, durch die sich ein Teil des Kraftstoffhochdrucks aus dem Steuerraum 29 in den Vorratstank 5 entspannt, wird der Steuerraum 29 erneut mit der Druckleitung 9 verbunden und mit dem hohen Systemdruck gefüllt.The control unit 39 adjusts the electromagnet 37 the shutdown of the internal combustion engine to be supplied with high Frequency, e.g. through a shared control (analog pre and main injection) can be achieved. This leads to the short current supply to the electromagnet 37 actuated by this valve member of the 3/2-way control valve 31 only one ballistic needle stroke (NH), so that 3/2-way control valve 31 the connection between the Control room 29 and the discharge line 35 are not complete opens. In this way it is ensured that the Pressure in the control room 29 does not drop so far that the Differential pressure to the pressure chamber 23 is sufficient, the valve member 15 of the injection valve 11 lift off from its seat 19 to let. After this brief opening of the connection Control room 29 and discharge line 35 through which one Part of the high fuel pressure from the control chamber 29 in the Storage tank 5 relaxed, the control room 29 is again with the pressure line 9 connected and with the high system pressure filled.

Dieses kurzzeitige Aufsteuern der Verbindung Steuerraum 29 zur Entlastungsleitung 35 erfolgt dabei so lange, bis der Kraftstoffhochdruck im Hochdruckspeicherraum 7 auf einen bestimmten Wert (ΔP) abgesunken ist. Die einzelnen Einspritzventile 11 werden dabei nacheinander angesteuert, was zum Beispiel in der Reihenfolge der Zündfolge der einzelnen Zylinder der Brennkraftmaschine erfolgen kann.This brief opening of the control room 29 connection to the relief line 35 takes place until the High fuel pressure in the high-pressure storage space 7 to a certain Value (ΔP) has dropped. The individual injectors 11 are controlled one after the other, which for Example in the order of the firing order of the individual cylinders the internal combustion engine can take place.

Der Vorgang der Druckreduzierung wird dabei mittels des Drucksensors 43 vom Steuergerät 39 überwacht, das in Abhängigkeit vom im Hochdruckspeicherraum 7 anliegenden Druck die Ansteuerdauer der 3/2-Wegesteuerventile 31 anpaßt. Dabei werden die Elektromagneten 37 bei hohem Druck kürzer angesteuert als bei niedrigem, so daß sich eine optimale Entleerungszeit bei gleichzeitigem sicheren Vermeiden einer Kraftstoffeinspritzung erreichen läßt.The process of reducing pressure is carried out by means of the Pressure sensor 43 monitored by the control unit 39, which in Dependence on the pressure in the high-pressure storage space 7 Pressure adjusts the control duration of the 3/2-way control valves 31. The electromagnets 37 become shorter at high pressure controlled than at low, so that there is an optimal Drain time while safely avoiding one Can achieve fuel injection.

Das in der Figur 2 dargestellte zweite Ausführungsbeispiel einer Kraftstoffeinspritzeinrichtung zur Durchführung des erfindungsgemäßen Verfahrens unterscheidet sich zum ersten in der Figur 1 gezeigten Ausführungsbeispiel lediglich in der Art der Verbindung des Steuerraumes 29 am Einspritzventil 11 mit der Druckleitung 9 und der Entlastungsleitung 35 sowie dem Aufbau des Steuerventils, daß dort als 2/2-Wegesteuerventil 45 ausgebildet ist und die Verbindung des Steuerraumes 29 zur Entlastungsleitung 35 auf- bzw. zusteuert. Der Steuerraum 29 ist dabei über einen eine erste Drosselstelle 47 enthaltene Verbindungsleitung 49 mit der Druckleitung 9 verbunden. In den Verbindungskanal 30 zum 2/2-Wegesteuerventil 45 ist eine zweite Drosselstelle 51 eingesetzt, über deren Auslegung der Abströmvorgang des Kraftstoffes aus dem Steuerraum 29 in den Vorratstank 5 und somit die Öffnungshubbewegung des Ventilgliedes 15 einstellbar ist.The second embodiment shown in Figure 2 a fuel injector for performing the The method according to the invention differs for the first In the embodiment shown in Figure 1 only in the type of connection of the control chamber 29 to the injection valve 11 with the pressure line 9 and the relief line 35 and the structure of the control valve that there as a 2/2-way control valve 45 is formed and the connection of the Control room 29 to the relief line 35 up or controls. The control chamber 29 is a first one Throttle point 47 contained connecting line 49 with the Pressure line 9 connected. In the connecting channel 30 to 2/2-way control valve 45 is a second throttle point 51 used, on the design of the discharge process of Fuel from the control room 29 in the storage tank 5 and thus the opening stroke movement of the valve member 15 adjustable is.

Das zweite Ausführungsbeispiel arbeitet analog zum Ersten, wobei während des Betriebs der Brennkraftmaschine infolge des Öffnens der Verbindung Steuerraum 29 Entlastungsleitung 35 durch das vom Elektromagneten 37 gesteuerte 2/2-Wegesteuerventil 45 das Abheben des Ventilgliedes 15 vom Ventilsitz 19 und somit der Einspritzvorgang erfolgt.The second embodiment works analogously to the first, whereby during the operation of the internal combustion engine as a result opening the connection control room 29 relief line 35 by the 2/2-way control valve controlled by the electromagnet 37 45 the lifting of the valve member 15 from the valve seat 19 and thus the injection process takes place.

Die Druckentlastung des Hochdruckspeicherraumes 7 nach Abstellen der Brennkraftmaschine erfolgt wie im ersten Ausführungsbeispiel beschrieben durch das kurzzeitige Aufsteuern der Verbindung Steuerraum 29 und Entlastungsleitung 35, so daß über das ständige Nachbefüllen des Steuerraumes 29 aus dem Hochdruckspeicherraum 7 dessen Druck abgesenkt werden kann. Auch hier erfolgt die Druckentlastung des Steuerraumes 29 nur so kurz und in jeweils so geringem Maß, daß keine Einspritzung an den Einspritzventilen 11 erfolgt. Das dritte in der Figur 3 dargestellte Ausführungsbeispiel weist nur einen auf das Ventilglied 15 wirkenden Druckraum 323 am Einspritzventil 11 auf, über dessen mittels des 3/2-Wegesteuerventils 31 gesteuerte Verbindung mit der Druckleitung 9 vom Hochdruckspeicherraum 7 in bekannter Weise der Öffnungshub des Ventilgliedes 15 entgegen der Kraft der Ventilfeder 28 und somit das Öffnen des Einspritzventils 11 erfolgt, wogegen über die Verbindung des Druckraumes 323 mit der Entlastungsleitung 35 die Druckentlastung und in Folge das Schließen des Einspritzventils 11 erfolgt. Dabei gewährleistet ein in die Entlastungsleitung 35 eingesetztes Druckventil einen bestimmten Standdruck im Druckraum 323. Die Reduzierung des Kraftstoffhochdruckes im Hochdruckspeicherraum 7 nach Abstellen der Brennkraftmaschine erfolgt im dritten Ausführungsbeispiel durch eine kurzzeitige Verbindung des Druckraumes 323 mit der Druckleitung 9, die jedoch wiederum derart kurz erfolgt, daß sich einerseits der für eine Einspritzung notwendige Druck im Druckraum 323 nicht aufbauen kann, der Druck aber andererseits über dem Öffnungsdruck des Druckventils 53 in der Entlastungsleitung 35 liegt, so daß der Hochdruck im Hochdruckspeicherraum 7 wie bereits beschrieben durch mehrmaliges Ansteuern des 3/2-Wegesteuerventils 31 bis auf den Öffnungsdruck des Druckventils 53 abgebaut werden kann.The pressure relief of the high pressure storage space 7 after switching off the internal combustion engine takes place as in the first Embodiment described by the short-term Open the connection between control room 29 and relief line 35, so that the constant refilling of the control room 29 from the high-pressure storage space 7 whose pressure is reduced can be. The pressure relief of the Control room 29 only so short and to such a small extent, that there is no injection at the injection valves 11. The third embodiment shown in Figure 3 has only one pressure chamber acting on the valve member 15 323 on the injection valve 11, via the 3/2-way control valve 31 controlled connection to the pressure line 9 of the high-pressure storage space 7 in a known manner Opening stroke of the valve member 15 against the force of the valve spring 28 and thus the opening of the injection valve 11 takes place, while on the connection of the pressure chamber 323 with the relief line 35 the pressure relief and in a row the injection valve 11 is closed. Here ensures an inserted in the relief line 35 Pressure valve a certain stand pressure in the pressure chamber 323. The reduction of high fuel pressure in the high-pressure storage space 7 after switching off the internal combustion engine takes place in third embodiment by a short-term connection of the pressure chamber 323 with the pressure line 9, however again so short that on the one hand the for an injection does not require pressure in the pressure chamber 323 can build up, but on the other hand the pressure above Opening pressure of the pressure valve 53 in the relief line 35 is so that the high pressure in the high pressure storage space 7th as already described by activating the 3/2-way control valve several times 31 up to the opening pressure of the pressure valve 53 can be reduced.

Es ist somit mit dem erfindungsgemäßen Verfahren möglich, eine aus Sicherheitsgründen notwendige Druckreduzierung im Einspritzsystem nach Abstellen der zu versorgenden Brennkraftmaschine zu ermöglichen, ohne dazu zusätzliche, kostenaufwendige Druckventile vorzusehen.It is thus possible with the method according to the invention a pressure reduction in the Injection system after switching off the internal combustion engine to be supplied to enable without additional to provide costly pressure valves.

Claims (9)

  1. Method for reducing the fuel pressure in a fuel injection device for internal combustion engines, the said fuel injection device having a pump (1) for feeding fuel into a high-pressure storage space (7), from which pressure conduits (9) lead off to injection valves (11), and with a control valve (31) located on the injection valve (11) and controlling injection through the injection valve (11), the said control valve, for control, connecting a pressure space (29,323) of the injection valve (11), the said pressure space acting on a valve member (15) of the injection valve (11), to the high-pressure storage space (7) or to a rellief conduit (35) into a supply tank (5), characterized in that, after the internal combustion engine has been switched off and the feed of the pump (1) has ended, the pressure in the high-pressure storage space (7) is relieved into the supply tank (5) via the control valve (31), for which purpose the control valve (31) briefly connects the pressure space (29, 323) of the injection valve (11) to the high-pressure storage space (7) or to the supply tank (5), in such a way that the pressure acting on the valve member (15) of the injection valve (11) in the opening direction remains below an opening pressure of the injection valve (11), this operation to activate the control valve (31, 323) being repeated until a desired reduced pressure is reached in the high-pressure storage space (7).
  2. Method according to Claim 1, characterized in that the control valves (31, 45) are activated at high frequencies in order to reduce the pressure in the high-pressure storage space (7) after the internal combustion engine has been switched off.
  3. Method according to Claim 1, characterized in that the control valves (31, 45) provided on the individual injection valves (11) are activated in succession in order to reduce the pressure in the high-pressure storage space (7) after the internal combustion engine has been switched off.
  4. Fuel injection device for carrying out the method according to Claim 1, with a fuel injection device for internal combustion engines, which has a pump (1) for feeding fuel into a high-pressure storage space (7), from which pressure conduits (9) lead off to injection valves (11), and with a control valve (31) located on the injection valve (11) and controlling injection through the injection valve (11), the said control valve, for control, connecting a pressure space (29, 323) of the injection valve (11), the said pressure space acting on a valve member (15) of the injection valve (11), to the high-pressure storage space (7) or to a relief conduit (35) into a supply tank (5), characterized in that there are provided on the injection valve (11) two pressure spaces which act on the injection valve member (15) and of which a first pressure space (23), acting on the valve member in the opening direction, is constantly connected to the high-pressure storage space (7) and a second pressure space, which forms a control space (29) and acts on the valve member (15) in the closing direction, can be connected to the high-pressure storage space (7) or to a relief space (5) by means of the control valve (31) designed as a 3/2-way valve, and with means for activating the control valve (31) in such a way that, after the internal combustion engine has been switched off, a relief of pressure out of the high-pressure storage space (7) into the supply tank (5) takes place, for which purpose the control valve (31) briefly connects the control space (29) of the injection valve (11) to the high-pressure storage space (7) or to the supply tank (5), in such a way that the pressure acting on the valve member (15) of the injection valve (11) in the opening direction remains below an opening pressure of the injection valve (11), this operation to activate the control valve (31) being repeated until a desired reduced pressure is reached in the high-pressure storage space (7).
  5. Fuel injection device for carrying out the method according to Claim 1, with a fuel injection device for internal combustion engines, which has a pump (1) for feeding fuel into a high-pressure storage space (7), from which pressure conduits (9) lead off to injection valves (11), and with a control valve (31) located on the injection valve (11) and controlling injection through the injection valve (11), the said control valve, for control, connecting a pressure space (29, 323) of the injection valve (11), the said pressure space acting on a valve member (15) of the injection valve (11), to the high-pressure storage space (7) or to a relief conduit (35) into a supply tank (5), characterized in that there are provided on the injection valve (11) two pressure spaces which act on the injection valve member (15) and of which a first pressure space (23), acting on the valve member (15) in the opening direction, is constantly connected to the high-pressure storage space (7) and a second pressure space, which forms a control space (29) and acts on the valve member (15) in the closing direction and which is constantly connected to the high-pressure storage space (7) via a connecting conduit (49) containing a first throttle (47), can be connected to a relief space (5) by means of a control valve designed as a 2/2-way valve (45), and with means for activating the control valve (45) in such a way that, after the internal combustion engine has been switched off, a relief of pressure out of the high-pressure storage space (7) into the supply tank (5) takes place, for which purpose the control valve (31) briefly connects the control space (29) of the injection valve (11) to the high-pressure storage space (7) or to the supply tank (5), in such a way that the pressure acting on the valve member (15) of the injection valve (11) in the opening direction remains below an opening pressure of the injection valve (11), this operation to activate the control valve (31) being repeated until a desired reduced pressure is reached in the high-pressure storage space (7).
  6. Fuel injection device for carrying out the method according to Claim 1, with a fuel injection device for internal combustion engines, which has a pump (1) for feeding fuel into a high-pressure storage space (7), from which pressure conduits (9) lead off to injection valves (11), and with a control valve (31) located on the injection valve (11) and controlling injection through the injection valve (11), the said control valve, for control, connecting a pressure space (29, 323) of the injection valve (11), the said pressure space acting on a valve member (15) of the injection valve (11), to the high-pressure storage space (7) or to a relief conduit (35) into a supply tank (5), characterized in that there is provided on the injection valve (11) a pressure space (323) which acts on the valve member (15) in the opening direction and which can be connected to the high-pressure storage space (7) or to a relief space (5) by means of the control valve designed as a 3/2-way valve (31), and with means for activating the control valve (31) in such a way that, after the internal combustion engine has been switched off, a relief of pressure out of the high-pressure storage space (7) into the supply tank (5) takes place, for which purpose the control valve (31) briefly connects the pressure space (323) of the injection valve (11) to the high-pressure storage space (7) or to the supply tank (5), in such a way that the pressure acting on the valve member (15) of the injection valve (11) in the opening direction remains below an opening pressure of the injection valve (11), this operation to activate the control valve (31, 323) being repeated until a desired reduced pressure is reached in the high-pressure storage space (7).
  7. Fuel injection device according to Claim 6, characterized in that a pressure valve (53) opening in the direction of the relief space (5) is arranged in the relief conduit (35) leading to the relief space (5).
  8. Fuel injection device according to Claims 4 to 6, characterized in that the control valve (31, 45) is connected to an electromagnet (37) which actuates the latter and which is activated by a control unit (39) processing operating parameters of the internal combustion engine.
  9. Fuel injection device according to Claim 7, characterized in that a pressure sensor (43), which is connected to the control unit (39) and which is preferably inserted into the high-pressure storage space (7), is provided.
EP95919966A 1994-12-20 1995-06-01 Process for reducing the fuel pressure in a fuel injection system Expired - Lifetime EP0745184B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE4445586A DE4445586A1 (en) 1994-12-20 1994-12-20 Method for reducing fuel pressure in a fuel injector
DE4445586 1994-12-20
PCT/DE1995/000713 WO1996019659A1 (en) 1994-12-20 1995-06-01 Process for reducing the fuel pressure in a fuel injection system

Publications (2)

Publication Number Publication Date
EP0745184A1 EP0745184A1 (en) 1996-12-04
EP0745184B1 true EP0745184B1 (en) 1998-10-28

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EP95919966A Expired - Lifetime EP0745184B1 (en) 1994-12-20 1995-06-01 Process for reducing the fuel pressure in a fuel injection system

Country Status (6)

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US (1) US5711274A (en)
EP (1) EP0745184B1 (en)
JP (1) JPH09509716A (en)
KR (1) KR100378722B1 (en)
DE (2) DE4445586A1 (en)
WO (1) WO1996019659A1 (en)

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Also Published As

Publication number Publication date
EP0745184A1 (en) 1996-12-04
DE4445586A1 (en) 1996-06-27
US5711274A (en) 1998-01-27
DE59504070D1 (en) 1998-12-03
WO1996019659A1 (en) 1996-06-27
JPH09509716A (en) 1997-09-30
KR970701309A (en) 1997-03-17
KR100378722B1 (en) 2003-06-19

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