EP0931215A1 - Fuel injection device for internal combustion engines - Google Patents

Fuel injection device for internal combustion engines

Info

Publication number
EP0931215A1
EP0931215A1 EP98928123A EP98928123A EP0931215A1 EP 0931215 A1 EP0931215 A1 EP 0931215A1 EP 98928123 A EP98928123 A EP 98928123A EP 98928123 A EP98928123 A EP 98928123A EP 0931215 A1 EP0931215 A1 EP 0931215A1
Authority
EP
European Patent Office
Prior art keywords
valve
fuel injection
valve seat
injection device
chamber
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
EP98928123A
Other languages
German (de)
French (fr)
Other versions
EP0931215B1 (en
Inventor
Friedrich Boecking
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP0931215A1 publication Critical patent/EP0931215A1/en
Application granted granted Critical
Publication of EP0931215B1 publication Critical patent/EP0931215B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • 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
    • 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
    • F02M63/0012—Valves
    • F02M63/0014—Valves characterised by the valve actuating means
    • F02M63/0015—Valves characterised by the valve actuating means electrical, e.g. using solenoid
    • F02M63/0026—Valves characterised by the valve actuating means electrical, e.g. using solenoid using piezoelectric or magnetostrictive actuators
    • 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
    • F02M45/00—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship
    • F02M45/02—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship with each cyclic delivery being separated into two or more parts
    • F02M45/04—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship with each cyclic delivery being separated into two or more parts with a small initial part, e.g. initial part for partial load and initial and main part for full load
    • 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
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/70—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger
    • F02M2200/703—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger hydraulic
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/70—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger
    • F02M2200/703—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger hydraulic
    • F02M2200/704—Linkage between actuator and actuated element, e.g. between piezoelectric actuator and needle valve or pump plunger hydraulic with actuator and actuated element moving in different directions, e.g. in opposite directions

Definitions

  • the invention is based on a fuel injection device for internal combustion engines according to the preamble of claim 1.
  • the control valve is designed as a single-acting flat seat valve which controls the exit of the drainage channel from the control chamber with its sealing surface.
  • the control valve is actuated by a piston which has the pressure shoulder.
  • the piston is supported on a second piston by means of a compression spring, which in turn is adjustable by the piezo drive and, with its end face adjacent to the pressure shoulder, delimits the hydraulic pressure chamber.
  • This known control valve works so that it either opens or closes the drain channel. Accordingly, the injection valve member of the fuel injection valve assumes either an open or a closed position.
  • the fuel injection device with the characterizing features of claim 1, however, has the advantage that two valve seats are provided in the course of the drain channel, and the closing body with its sealing surfaces is adjusted from one valve seat when actuated by the piezo drive to the other valve seat in a single sequence of movements, after an initial closure of the drain channel in the meantime is opened via the valve chamber and then closed again.
  • this leads to a very brief relief of the control space, which results in an opening of the fuel injection valve member with also a very short fuel injection.
  • very small injection quantities can advantageously be controlled, which is determined by the sequence of movements of the closing body from one valve seat to the other.
  • This sequence of movements is essentially dependent on a single excitation of the piezo drive and can therefore be limited to a very short period of time.
  • the time required for this injection can be kept technically much smaller than if the control valve for the same pre-injection process is opened twice with a first excitation of the piezo drive and then closed by reducing the excitation with a fuel injection device of the generic type.
  • This switching always requires a time-consuming reversal of the movement of the control valve member and a time component must also be included, which is required for the respective change in the excitation state of the piezo drive.
  • the loss time for the control of the injection sequence pre-injection and main injection in the solution according to the invention is considerably less.
  • the fuel injection device it is possible according to the fuel injection device according to the invention to hold the closing body in an intermediate position in the above position by appropriate metering of the excitation of the piezo drive
  • the control chamber is relieved for a longer period of time and can then be used to inject the desired main injection quantity following the pre-injection quantity introduced in the manner described above and an injection pause.
  • an injection can thus be realized in a highly precise manner, in which exactly very small fuel pre-injection quantities are injected, exactly a period of time between the pre-injection and the main injection can be maintained and, subsequently, also in the usual manner also produces the main injection in a very precisely metered manner becomes.
  • the stroke of the closing body is matched to the actuating speed by the piezo drive in such a way that the desired pre-injection quantity is achieved.
  • FIG. 1 shows the schematic representation of a fuel injection device of a known type
  • FIG. 2 shows the design of the control valve for the fuel injection device according to FIG. 1
  • FIG. 3 shows the movement sequence of the valve member of the control valve plotted over the stroke course of the injection valve member of the fuel injection valve. Description of the embodiment
  • FIG. 1 shows a fuel injection device of a known type with a fuel injection valve 1, which has an injection valve housing 2 with a bore 3, in which an injection valve member 5 is guided. This has at one end a conical sealing surface 6 which cooperates with a conical valve seat 7 at the end of the bore. Downstream of the valve seat 7 Kraf fuel injection openings 8 are arranged, which at
  • the pressure chamber 9 extends over an annular space 10 around the part 11 of the injection valve member, which adjoins the sealing surface 6 upstream and has a smaller diameter, towards the valve seat 7.
  • the pressure chamber 9 is in constant communication with a high-pressure fuel source 14 via a pressure line 12.
  • the part 11 of the injection valve member with a smaller diameter merges with a pressure shoulder 16 facing the valve seat 7 into a part 18 of the injection valve member with a larger diameter. This is tightly guided in the bore 3 and continues on the side facing away from the pressure shoulder 16 in a connecting part 19 up to a piston-shaped end 20 of the injection valve member.
  • this has a spring plate 22, between which and the housing 1 of the fuel injection valve a compression spring 21 is clamped, which acts on the fuel injection valve member in the closed position.
  • the piston-like end 20 delimits, with an end face 24, the area of which is larger than that of the pressure shoulder 16, in the housing 2 of the fuel injection valve a control chamber 25 which is in constant communication with the high-pressure fuel source 14 via a first throttle 26 and via a second throttle 27 arranged in a drain channel 28 is connected to a relief chamber 29.
  • the passage of the drain channel 28 is controlled by a control valve 31 with which the drain channel is either opened or closed.
  • the control valve 21 in the embodiment now designed according to the invention can be seen in FIG. 2.
  • the piston-like end 20 of the injection valve member is shown, which delimits the control chamber 25 in the fuel injection valve housing 2.
  • An inflow channel 33 containing the first throttle 26 opens into the control chamber, so that the control chamber 25 is continuously connected to the high-pressure fuel source 14.
  • the discharge channel 28 with the second throttle 27 leads from the control chamber 25 coaxially to the piston-shaped end 20.
  • Drain channel opens into a valve chamber 35 and has a first valve seat 36 at the confluence thereof, which is preferably designed as a conical valve seat.
  • a conical first sealing surface 37 of a closing body 38 interacts with this, which is adjustably arranged in the valve chamber 35 and has a second, likewise conical sealing surface 39 on its side facing away from the first valve surface 37, which with a corresponding position of the closing body 38 has a second valve seat 40, which is also conical, acts together.
  • the closing body 38 is located at the end of a plunger 42 which is guided in a guide bore 43 in the housing 2 of the fuel injection valve.
  • the guide bore 43 ends in an annular space 44, which extends between the guide bore 43 and the second valve seat 40 or the second sealing surface 39 and is delimited by the tappet 42 and the wall of the housing 2.
  • the annular space 44 is in constant communication with a further part 46 of the Drain channel that leads to the relief chamber 29.
  • the guide bore 43 opens into a spring chamber 48, within which the tappet 42 has a spring plate 49, between which and the housing 2 of the fuel injection valve a compression spring 50 is supported, which together with its closing body pushes the tappet in the direction of the first valve seat 36 acted out.
  • the tappet From the spring chamber 48, the tappet continues in a guide bore into a hydraulic pressure chamber 52, which is enclosed by a first piston 53 at the end of a cylinder bore 54, which serves to guide this piston.
  • a second piston 56 is guided coaxially to the first piston 53 in a blind bore 57 of the first piston, which limits the pressure chamber 52 with its first end face 58 acting as a pressure shoulder and together with the adjacent end face 59 of the first piston 53 as a movable wall.
  • the second end face 60 of the second piston 56 includes a first relief region 61 in the blind bore 57, which passes through a bore 62 through the bottom of the first piston 53 into a second relief region 62.
  • a piezo drive 65 acts as a drive, which can be assembled in a known manner from several elements and is excited by a control device (not shown further here) or is de-energized and experiences a linear expansion with high force when excited, which is transmitted to the first piston 53.
  • the first piston 53 is held in constant contact with the piezo drive 65 by a plate spring 66 which is arranged in the hydraulic pressure chamber 52.
  • the piezo drive 65 is not energized and the plunger 42 is actuated by the compression spring 50. proposes that the first sealing surface 37 is in tight contact with the first valve seat 36 and thus the control chamber 25 is closed. Accordingly, there arises the pressure which also prevails in the high-pressure fuel source 14, because of the constant connection between the latter and the control chamber 25 via the inflow channel 33.
  • This high pressure loads the injection valve member in such a way that it opposes the pressure forces acting on the pressure shoulder 16 Is held in the closed position, supported by the compression spring 21.
  • Blind bore 57 is immersed, displacing fuel from the first relief region 61 into the second relief region 62. This has increased in volume and thereby supports the immersion movement of the second piston into the blind bore 57. The operation in turn has the consequence that the plunger 42 moves against the force of the compression spring 50 and thereby the closing body 38 lifts off the first valve seat 36. At the moment, the control chamber 25 is relieved, since the drain channel 28 is connected to the further drain channel part 46 through the now open valve seats 36 and 40.
  • the closing body subsequently keeps the drain channel 28-46 closed, and the pressure increase in the control chamber 25 brings the injection valve member 5 permanently into the closed position.
  • the control chamber 25 for actuating the injection valve member for a main injection can subsequently be relieved after an injection break by the piezo drive being actuated in such a way that the closing body 38 is in an intermediate position between the first valve seat 36 and the second valve seat 40 remain. This is the special advantage of a piezo drive that it can also take intermediate positions according to excitation.
  • FIG. 3 shows the sequence of movements of the control valve in the upper curve and the sequence of movements of the fuel injection valve member 5 in the lower curve.
  • the upper curve shows that when the piezo drive is excited at point 0 of the abscissa, the plunger 42 travels a negative stroke over time from h a until the closing body 38 has reached the second valve seat 40 at height h 0 . About this stroke results there is an injection valve member movement V corresponding to a pre-injection in the diagram below.
  • the smallest injection quantities for operating an internal combustion engine with pre-injection and main injection can be achieved.
  • This arrangement has the particular advantage that the piezo drive is only energized when an injection is to take place. The piezo drive is therefore de-energized for most of the operation of the internal combustion engine and electrical energy is only required for the injection processes.

Landscapes

  • 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)
  • Fuel-Injection Apparatus (AREA)

Abstract

The invention concerns a fuel injection device for internal combustion engines, wherein the displacement of a member closing the fuel injection valve is controlled by pressure prevailing in a control chamber (25). The pressure prevailing in said chamber is further controlled by a pilot valve (31) whereof the closure member can be actuated by a piezoelectric drive (65), the movement being transmitted via a hydraulic chamber. Said closure member comprises two sealing surfaces (37, 39) which co-operate with valve seats (36, 40), and when it passes from one valve seat to the other, a brief discharge occurs in the control chamber (25), to control a brief fuel injection. In order to obtain larger amounts of injected fuel, the pilot valve can be put in open or closed position.

Description

Kraftstoffeinspritzvorrichtung für BrennkraftmaschinenFuel injection device for internal combustion engines
Stand der TechnikState of the art
Die Erfindung geht von einer Kraftstoffeinspritzvorrichtung für Brennkraftmaschinen nach der Gattung des Patentanspruchs 1 aus. Bei einer durch die DE-Cl-195 19 192 bekannten Kraftstoffeinspritzvorrichtung dieser Art ist das Steuerventil als einfach wirkendes Flachsitzventil ausgebildet, das mit seiner Dichtfläche den Austritt des Abflußka- nals aus dem Steuerraum steuert. Das Ventilglied diesesThe invention is based on a fuel injection device for internal combustion engines according to the preamble of claim 1. In a fuel injection device of this type known from DE-Cl-195 19 192, the control valve is designed as a single-acting flat seat valve which controls the exit of the drainage channel from the control chamber with its sealing surface. The valve member of this
Steuerventils wird dabei durch einen Kolben, der die Druckschulter aufweist, betätigt. Der Kolben stützt sich über eine Druckfeder an einem zweiten Kolben ab, der seinerseits durch den Piezoantrieb verstellbar ist und mit seiner Stirnfläche, der Druckschulter nebengeordnet, den hydraulischen Druckraum begrenzt. Dieses bekannte Steuerventil arbeitet so, daß es entweder den Abflußkanal öffnet oder verschließt. Dem entsprechend nimmt das Einspritzventilglied des Kraftstoffeinspritzventils entweder eine geöffnete oder eine geschlossene Stellung ein.The control valve is actuated by a piston which has the pressure shoulder. The piston is supported on a second piston by means of a compression spring, which in turn is adjustable by the piezo drive and, with its end face adjacent to the pressure shoulder, delimits the hydraulic pressure chamber. This known control valve works so that it either opens or closes the drain channel. Accordingly, the injection valve member of the fuel injection valve assumes either an open or a closed position.
Vorteile der ErfindungAdvantages of the invention
Die erfindungsgemäße Kraftstoffeinspritzvorrichtung mit den kennzeichnenden Merkmalen des Patentanspruchs 1 hat dagegen den Vorteil, daß zwei Ventilsitze im Laufe des Abflußkanals vorgesehen sind, und der Schließkörper mit seinen Dichtflächen vom einen Ventilsitz bei Betätigung durch den Piezo- antrieb zum anderen Ventilsitz in einer einzigen Bewe- gungsabfolge verstellt wird, wobei nach einem anfänglichen Verschluß des Abflußkanals dieser zwischenzeitlich über den Ventilraum geöffnet wird und anschließend wieder verschlossen wird. Dies führt in der Bewegungsabfolge des Schließkörpers eine sehr kurzzeitige Entlastung des Steuerraumes herbei, was ein Öffnen des Kraftstoffeinspritzventilglieds mit ebenfalls sehr kurzzeitigen Kraftstoffeinspritzung zur Folge hat. Auf diese Weise können vorteilhaft sehr kleine Einspritzmengen gesteuert werden, die durch den Bewegungsablauf des Schließkörpers vom einen zum anderen Ventilsitz bestimmt ist. Dieser Bewegungsablauf ist wesentlich von einer einzigen Erregung des Piezoantriebs abhängig und kann deshalb auf einen sehr kurzen Zeitraum begrenzt sein. Der Zeitbedarf für diese Einnspritzung läßt sich technisch wesentlich kleiner halten, als wenn mit einer Kraftstoffein- spritzvorrichtung der gattungsgemäßen Art das Steuerventil für denselben Vorgang der Voreinspritzung zweimal mit einer ersten Erregung des Piezoantriebs geöffnet wird und dann durch Abbau der Erregung geschlossen wird. Dieses Schalten macht jedesmal eine zeitraubende Bewegungsumkehr des Steuerventilglieds erforderlich und es ist ferner noch eine Zeitkomponente miteinzurechnen, die für die jeweilige Änderung des Erregungszustandes des Piezoantriebs erforderlich ist. Somit ist die Verlustzeit für die Steuerung der Einspritzfolge Vor- und Haupteinspritzung bei der erfindungsgemäßen Lösung wesentlich geringer.The fuel injection device according to the invention with the characterizing features of claim 1, however, has the advantage that two valve seats are provided in the course of the drain channel, and the closing body with its sealing surfaces is adjusted from one valve seat when actuated by the piezo drive to the other valve seat in a single sequence of movements, after an initial closure of the drain channel in the meantime is opened via the valve chamber and then closed again. In the sequence of movements of the closing body, this leads to a very brief relief of the control space, which results in an opening of the fuel injection valve member with also a very short fuel injection. In this way, very small injection quantities can advantageously be controlled, which is determined by the sequence of movements of the closing body from one valve seat to the other. This sequence of movements is essentially dependent on a single excitation of the piezo drive and can therefore be limited to a very short period of time. The time required for this injection can be kept technically much smaller than if the control valve for the same pre-injection process is opened twice with a first excitation of the piezo drive and then closed by reducing the excitation with a fuel injection device of the generic type. This switching always requires a time-consuming reversal of the movement of the control valve member and a time component must also be included, which is required for the respective change in the excitation state of the piezo drive. The loss time for the control of the injection sequence pre-injection and main injection in the solution according to the invention is considerably less.
Dabei ist es gemäß der erfindungsgemäßen Kraftstoffeinspritzvorrichtung möglich, durch entsprechende Dosierung der Erregung des Piezoantriebs den Schließkörper in einer Zwischenstellung zu halten, in der über der vorstehenden Arbeitsweise längere Zeit eine Entlastung des Steuerraums erfolgt und über die dann die gewünschte Haupteinspritzmenge im Anschluß an die in der vorbeschriebenen Weise eingebrachten Voreinspritzmenge sowie einer Einspritzpause zur Einspritzung gelangen kann. Mit der erfindungsgemäßen Kraftstoffeinspritzvorrichtung läßt sich somit in höchst genauer Weise eine Einspritzung verwirklichen, bei der exakt sehr kleine Kraftstoffvoreinspritzmengen zur Einspritzung kommen, exakt ein Zeitraum zwischen Voreinspritzung und Haupteinspritzung eingehalten werden kann und in der Folge in der üblichen Weise ebenfalls sehr genau dosiert die Haupteinspritzung bewirkt wird.It is possible according to the fuel injection device according to the invention to hold the closing body in an intermediate position in the above position by appropriate metering of the excitation of the piezo drive The control chamber is relieved for a longer period of time and can then be used to inject the desired main injection quantity following the pre-injection quantity introduced in the manner described above and an injection pause. With the fuel injection device according to the invention, an injection can thus be realized in a highly precise manner, in which exactly very small fuel pre-injection quantities are injected, exactly a period of time between the pre-injection and the main injection can be maintained and, subsequently, also in the usual manner also produces the main injection in a very precisely metered manner becomes.
In vorteilhafter Weise wird dabei gemäß Patentanspruch 2 der Hub des Schließkörpers mit der Stellgeschwindigkeit durch den Piezoantrieb so abgestimmt, daß die gewünschte Voreinspritzmenge erzielt wird.In an advantageous manner, the stroke of the closing body is matched to the actuating speed by the piezo drive in such a way that the desired pre-injection quantity is achieved.
Vorteilhafte Weiterbildungen der Erfindung sind in den Patentansprüchen 3 bis 9 gegeben. Sie werden anhand der Zeichnungen und der nachfolgenden Beschreibung näher erläutert .Advantageous developments of the invention are given in claims 3 to 9. They are explained in more detail using the drawings and the description below.
Zeichnungdrawing
Ein Ausführungsbeispiel der Erfindung ist in der Zeichnung wiedergegeben und wird nachfolgend näher beschrieben. Es zeigen Figur 1 die schematische Darstellung einer Kraftstoffeinspritzvorrichtung bekannter Art, Figur 2 die Ausgestaltung des Steuerventils für die Kraftstoffeinspritzvorrichtung gemäß Figur 1 und Figur 3 den Bewegungsablauf des Ventilglieds des Steuerventils aufgetragen über den Hubverlauf des Einspritzventilgliedes des Kraf stoffeinspritzventils . Beschreibung des AusführungsbeispielsAn embodiment of the invention is shown in the drawing and is described in more detail below. 1 shows the schematic representation of a fuel injection device of a known type, FIG. 2 shows the design of the control valve for the fuel injection device according to FIG. 1 and FIG. 3 shows the movement sequence of the valve member of the control valve plotted over the stroke course of the injection valve member of the fuel injection valve. Description of the embodiment
Figur 1 zeigt eine Kraftstoffeinspritzvorrichtung bekannter Art mit einem Kraftstoffeinspritzventil 1, das ein Einspritzventilgehäuse 2 aufweist mit einer Bohrung 3, in der ein Einspritzventilglied 5 geführt ist. Dieses weist an seinem einen Ende eine kegelförmige Dichtfläche 6 auf, die mit einem kegelförmigen Ventilsitz 7 am Ende der Bohrung zusammenwirkt. Stromabwärts von des Ventilsitzes 7 sind Kraf stoffeinspritzöffnungen 8 angeordnet, die beimFIG. 1 shows a fuel injection device of a known type with a fuel injection valve 1, which has an injection valve housing 2 with a bore 3, in which an injection valve member 5 is guided. This has at one end a conical sealing surface 6 which cooperates with a conical valve seat 7 at the end of the bore. Downstream of the valve seat 7 Kraf fuel injection openings 8 are arranged, which at
Aufsetzten der Dichtfläche 6 auf dem Ventilsitz 7 von einem Druckraum 9 getrennt werden. Der Druckraum 9 erstreckt sich über einen Ringraum 10 um den sich an die Dichtfläche 6 stromaufwärts anschließenden Teil 11 des Einspritzventil- glieds mit kleinerem Durchmesser zum Ventilsitz 7 hin. Der Druckraum 9 ist über eine Druckleitung 12 in ständiger Verbindung mit einer Kraftstoffhochdruckquelle 14. Im Bereich des Druckraumes 9 geht der im Durchmesser kleinere Teil 11 des Einspritzventilglieds mit einer zum Ventilsitz 7 weisenden Druckschulter 16 in einem im Durchmesser größeren Teil 18 des Einspritzventilglieds über. Dieser ist in der Bohrung 3 dicht geführt und setzt sich auf der der Druckschulter 16 abgewandten Seite in einem Verbindungsteil 19 fort bis hin zu einem kolbenförmigen Ende 20 des Einspritzventilglieds. Im Bereich des Verbindungsteils hat dieses einen Federteller 22, zwischen dem und dem Gehäuse 1 des Kraftstoffeinspritzventils eine Druckfeder 21 eingespannt ist, die das Kraftstoffeinspritzventilglied in Schließstellung beaufschlagt.Placing the sealing surface 6 on the valve seat 7 can be separated from a pressure chamber 9. The pressure chamber 9 extends over an annular space 10 around the part 11 of the injection valve member, which adjoins the sealing surface 6 upstream and has a smaller diameter, towards the valve seat 7. The pressure chamber 9 is in constant communication with a high-pressure fuel source 14 via a pressure line 12. In the area of the pressure chamber 9, the part 11 of the injection valve member with a smaller diameter merges with a pressure shoulder 16 facing the valve seat 7 into a part 18 of the injection valve member with a larger diameter. This is tightly guided in the bore 3 and continues on the side facing away from the pressure shoulder 16 in a connecting part 19 up to a piston-shaped end 20 of the injection valve member. In the area of the connecting part, this has a spring plate 22, between which and the housing 1 of the fuel injection valve a compression spring 21 is clamped, which acts on the fuel injection valve member in the closed position.
Das kolbenartige Ende 20 begrenzt mit einer Stirnseite 24 , deren Fläche größer ist als die der Druckschulter 16, im Gehäuse 2 des Kraftstoffeinspritzventils einen Steuerraum 25, der über eine erste Drossel 26 in ständiger Verbindung mit der Kraftstoffhochdruckquelle 14 ist und über eine zweite in einem Abflußkanal 28 angeordnete Drossel 27 zu einem Entlastungsraum 29 verbunden ist. Der Durchgang des Abflußkanals 28 wird durch ein Steuerventil 31 gesteuert, mit dem der Abflußkanal entweder geöffnet oder geschlossen wird.The piston-like end 20 delimits, with an end face 24, the area of which is larger than that of the pressure shoulder 16, in the housing 2 of the fuel injection valve a control chamber 25 which is in constant communication with the high-pressure fuel source 14 via a first throttle 26 and via a second throttle 27 arranged in a drain channel 28 is connected to a relief chamber 29. The passage of the drain channel 28 is controlled by a control valve 31 with which the drain channel is either opened or closed.
Das Steuerventil 21 in der nun erfindungsgemäß ausgestalteten Ausführung ist der Figur 2 zu entnehmen. Dort ist wiederum das kolbenartige Ende 20 des Einspritzventilgliedes gezeigt, das den Steuerraum 25 im Kraftstoffeinspritzventil- gehäuse 2 begrenzt . In den Steuerraum mündet ein die erste Drossel 26 enthaltender Zuflußkanal 33, sodaß der Steuerraum 25 ständig mit der Kraftstoffhochdruckquelle 14 verbunden ist. Koaxial zum kolbenförmigen Ende 20 führt vom Steuerraum 25 der Abflußkanal 28 mit der zweiten Drossel 27 ab. DerThe control valve 21 in the embodiment now designed according to the invention can be seen in FIG. 2. There, in turn, the piston-like end 20 of the injection valve member is shown, which delimits the control chamber 25 in the fuel injection valve housing 2. An inflow channel 33 containing the first throttle 26 opens into the control chamber, so that the control chamber 25 is continuously connected to the high-pressure fuel source 14. The discharge channel 28 with the second throttle 27 leads from the control chamber 25 coaxially to the piston-shaped end 20. The
Abflußkanal mündet dabei in einen Ventilraum 35 und weist an der Einmündung in diesen eine ersten Ventilsitz 36 auf, der vorzugsweise als kegelförmiger Ventilsitz ausgebildet ist. Mit diesem wirkt eine ebenfalls kegelförmig ausgebildete erste Dichtfläche 37 eines Schließkörpers 38 zusammen, der in dem Ventilraum 35 verstellbar angeordnet ist und auf seiner der ersten Ventilfläche 37 abgewandten Seite eine zweite, ebenfalls kegelförmige Dichtfläche 39 aufweist, die bei entsprechender Stellung des Schließkörpers 38 mit einem zweiten Ventilsitz 40, der ebenfalls kegelförmig ausgebildet ist, zusammen wirkt.Drain channel opens into a valve chamber 35 and has a first valve seat 36 at the confluence thereof, which is preferably designed as a conical valve seat. A conical first sealing surface 37 of a closing body 38 interacts with this, which is adjustably arranged in the valve chamber 35 and has a second, likewise conical sealing surface 39 on its side facing away from the first valve surface 37, which with a corresponding position of the closing body 38 has a second valve seat 40, which is also conical, acts together.
Der Schließkδrper 38 befindet sich am Ende eines Stößels 42, der in einer Führungsbohrung 43 im Gehäuse 2 des Kraftstoff- einspritzventils geführt ist. Die Führungsbohrung 43 endet in einem Ringraum 44, der sich zwischen der Führungsbohrung 43 und dem zweiten Ventilsitz 40 bzw. der zweiten Dichtfläche 39 erstreckt und von dem Stößel 42 und der Wand des Gehäuses 2 begrenzt wird. Der Ringraum 44 steht in ständiger Verbindung mit einem weiterführenden Teil 46 des Abflußkanals, der zu dem Entlastungsraum 29 führt. Anderen- endes mündet die Führungsbohrung 43 in einen Federraum 48, innerhalb dem der Stößel 42 einen Federteller 49 aufweist, zwischen dem und dem Gehäuse 2 des Kraftstoffeinspritz- ventils sich eine Druckfeder 50 abstützt, die den Stößel zusammen mit seinem Schließkörper in Richtung zum ersten Ventilsitz 36 hin beaufschlagt. Aus dem Federraum 48 heraus führt der Stößel weiter in einer Führungsbohrung in einen hydraulischen Druckraum 52, der von einem ersten Kolben 53 am Ende einer Zylinderbohrung 54, die der Führung dieses Kolbens dient, eingeschlossen ist. Koaxial zu dem ersten Kolben 53 ist ein zweiter Kolben 56 in einer Sackbohrung 57 des ersten Kolbens geführt, der mit seiner ersten als Druckschulter wirkenden Stirnseite 58 und zusammen mit der nebengeordneten Stirnseite 59 des ersten Kolbens 53 als bewegliche Wand den Druckraum 52 begrenzt. Die zweite Stirnseite 60 des zweiten Kolbens 56 schließt in der Sackbohrung 57 einen ersten Entlastungsbereich 61 ein, der durch eine Bohrung 62 durch den Boden des ersten Kolbens 53 in einen zweiten Entlastungsbereich 62 übergeht.The closing body 38 is located at the end of a plunger 42 which is guided in a guide bore 43 in the housing 2 of the fuel injection valve. The guide bore 43 ends in an annular space 44, which extends between the guide bore 43 and the second valve seat 40 or the second sealing surface 39 and is delimited by the tappet 42 and the wall of the housing 2. The annular space 44 is in constant communication with a further part 46 of the Drain channel that leads to the relief chamber 29. On the other hand, the guide bore 43 opens into a spring chamber 48, within which the tappet 42 has a spring plate 49, between which and the housing 2 of the fuel injection valve a compression spring 50 is supported, which together with its closing body pushes the tappet in the direction of the first valve seat 36 acted out. From the spring chamber 48, the tappet continues in a guide bore into a hydraulic pressure chamber 52, which is enclosed by a first piston 53 at the end of a cylinder bore 54, which serves to guide this piston. A second piston 56 is guided coaxially to the first piston 53 in a blind bore 57 of the first piston, which limits the pressure chamber 52 with its first end face 58 acting as a pressure shoulder and together with the adjacent end face 59 of the first piston 53 as a movable wall. The second end face 60 of the second piston 56 includes a first relief region 61 in the blind bore 57, which passes through a bore 62 through the bottom of the first piston 53 into a second relief region 62.
Auf der der Stirnseite 59 des ersten Kolbens 53 abgewandten Stirnseite 64, die in der Zylinderbohrung den Entlastungsbe- reich 62 begrenzt, wirkt als Antrieb ein Piezoantrieb 65, der in bekannter Weise aus mehreren Elementen zusammengesetzt werden kann und durch eine hier nicht weiter gezeigte Steuereinrichtung erregt bzw. entregt wird und bei Erregung eine Längenausdehnung mit hoher Kraftwirkung erfährt, die auf den ersten Kolben 53 übertragen wird.On the end face 59 facing away from the end face 59 of the first piston 53 and which delimits the relief region 62 in the cylinder bore, a piezo drive 65 acts as a drive, which can be assembled in a known manner from several elements and is excited by a control device (not shown further here) or is de-energized and experiences a linear expansion with high force when excited, which is transmitted to the first piston 53.
Der erste Kolben 53 wird durch eine Tellerfeder 66, die in dem hydraulischen Druckraum 52 angeordnet ist, in ständiger Anlage an dem Piezoantrieb 65 gehalten. In der in der Figur 2 gezeigten Stellung ist der Piezoantrieb 65 nicht erregt und es wird der Stößel 42 durch die Druckfeder 50 so beauf- schlagt, daß die erste Dichtfläche 37 in dichter Anlage am ersten Ventilsitz 36 ist und somit der Steuerraum 25 geschlossen ist. Demzufolge stellt sich dort der Druck ein, der auch in der Kraftstoffhochdruckquelle 14 herrscht, wegen der ständigen Verbindung zwischen dieser und dem Steuerraum 25 über den Zuflußkanal 33. Dieser hohe Druck belastet das Einspritzventilglied so, daß es entgegen der an der Druckschulter 16 wirkenden Druckkräfte in Schließstellung gehalten wird, unterstützt durch die Druckfeder 21.The first piston 53 is held in constant contact with the piezo drive 65 by a plate spring 66 which is arranged in the hydraulic pressure chamber 52. In the position shown in FIG. 2, the piezo drive 65 is not energized and the plunger 42 is actuated by the compression spring 50. proposes that the first sealing surface 37 is in tight contact with the first valve seat 36 and thus the control chamber 25 is closed. Accordingly, there arises the pressure which also prevails in the high-pressure fuel source 14, because of the constant connection between the latter and the control chamber 25 via the inflow channel 33. This high pressure loads the injection valve member in such a way that it opposes the pressure forces acting on the pressure shoulder 16 Is held in the closed position, supported by the compression spring 21.
Wird nun der Piezoantrieb erregt, so wird der erste Kolben 53 verschoben, was den Druck im hydraulischen Druckraum 52 erhöht, so daß in der Folge wegen des auf die Stirnseite 58 des zweiten, mit dem Stößel 42 verbundenen Kolbens 56 wirkenden Drucks dieser ausweicht und weiter in dieIf the piezo drive is now energized, the first piston 53 is displaced, which increases the pressure in the hydraulic pressure chamber 52, so that as a result of the pressure acting on the end face 58 of the second piston 56 connected to the tappet 42, the latter evades and continues in the
Sackbohrung 57 eintaucht, wobei er Kraftstoff aus dem ersten Entlastungsbereich 61 in den zweiten Entlastungsbereich 62 verdrängt. Dieser hat sich im Volumen vergrößert und unterstützt dabei die Eintauchbewegung des zweiten Kolbens in die Sackbohrung 57. Der Vorgang hat wiederum zur Folge, daß sich der Stößel 42 gegen die Kraft der Druckfeder 50 verschiebt und dabei den Schließkörper 38 vom ersten Ventilsitz 36 abhebt. In dem Moment erfolgt eine Entlastung des Steuerraums 25, da der Abflußkanal 28 mit dem weiterfüh- renden Abflußkanalteil 46 durch die nunmehr offenen Ventilsitze 36 und 40 verbunden ist. Ist die Erregung des Piezoantriebs 65 so groß, daß der Stößel 42 den Schließkörper 38 mit seiner zweiten Dichtfläche 39 an den zweiten Ventilsitz 40 zur Anlage bringt, so erfolgt ein Wiederverschluß des Abflußkanals, was zur Folge hat, daß im Steuerraum 25 nach zwischenzeitlicher Entlastung wieder der volle Druck der Kraftstoffhochdruckquelle aufgebaut wird. Wird dieser vorstehend beschriebene Vorgang in dieser Weise ausgeführt, so wird zwischen dem Öffnen am ersten Ventilsitz 36 und dem Wiederschließen des Abflußkanals am zweiten Ventilsitz 40 der Steuerraum 25 kurzzeitig entlastet. Dies hat zur Folge, daß auch das Einspritzventilglied 5 entlastet wird und kurzzeitig in eine zumindest teilgeöffnete Stellung bewegt wird. Damit kann, den kurzen Entlastungszeitraum zugrundegelegt, eine sehr kleine Kraftstoffeinspritzmenge zur Einspritzung gelangen. Am zweiten Ventilsitz 40 angelangt hält der Schließkörper in der Folge den Abflußkanal 28-46 verschlossen, und durch den Druckaufbau im Steuerraum 25 wird das Einspritzventilglied 5 wieder bleibend in Schließstellung gebracht. Anschließend an diese sehr kleine Kraftstoffeinspritzung, die vorzugseise eine Voreinspritzmenge sein kann, kann in der Folge nach einer Spritzpause der Steuerraum 25 zur Betätigung des Einspritzventilglieds für eine Haupteinspritzung wieder entlastet werden, indem der Piezoantrieb so angesteuert wird, daß der Schließkörper 38 in einer Zwischenstellung zwischen dem ersten Ventilsitz 36 und dem zweiten Ventilsitz 40 verharrt. Dies ist der besondere Vorzug eines Piezoantriebes, daß er auch Zwischenpositionen entsprechend einer Erregung einnehmen kann. Diese Zwischenposition wird nun solange beibehalten, bis die erforderliche Haupteinspritzmenge eingespritzt ist und dann die 'Erregung des Piezoantriebs beispielsweise ganz aufgehoben, so daß der Stößel mit Schließkörper 38 unter Einwirkung der Druckfeder 50 wieder in Schließstellung am ersten Ventilsitz 36 gelangt .Blind bore 57 is immersed, displacing fuel from the first relief region 61 into the second relief region 62. This has increased in volume and thereby supports the immersion movement of the second piston into the blind bore 57. The operation in turn has the consequence that the plunger 42 moves against the force of the compression spring 50 and thereby the closing body 38 lifts off the first valve seat 36. At the moment, the control chamber 25 is relieved, since the drain channel 28 is connected to the further drain channel part 46 through the now open valve seats 36 and 40. If the excitation of the piezo drive 65 is so great that the plunger 42 brings the closing body 38 with its second sealing surface 39 to the second valve seat 40, the drainage channel is reclosed, which has the consequence that in the control chamber 25 again after a relief the full pressure of the high-pressure fuel source is built up. If this process described above is carried out in this way, there will be between opening on the first valve seat 36 and reclosing the drain channel on the second Valve seat 40 temporarily relieves the control chamber 25. The result of this is that the injection valve member 5 is also relieved and is briefly moved into an at least partially open position. On the basis of the short relief period, a very small amount of fuel injection can thus be injected. Arrived at the second valve seat 40, the closing body subsequently keeps the drain channel 28-46 closed, and the pressure increase in the control chamber 25 brings the injection valve member 5 permanently into the closed position. Subsequent to this very small fuel injection, which can preferably be a pre-injection quantity, the control chamber 25 for actuating the injection valve member for a main injection can subsequently be relieved after an injection break by the piezo drive being actuated in such a way that the closing body 38 is in an intermediate position between the first valve seat 36 and the second valve seat 40 remain. This is the special advantage of a piezo drive that it can also take intermediate positions according to excitation. This intermediate position is now maintained until the required main injection quantity is injected and then the 'excitation of the piezo drive is completely canceled, for example, so that the plunger with the closing body 38, under the action of the compression spring 50, returns to the closed position on the first valve seat 36.
In der Figur 3 ist die Bewegungsabfolge des Steuerventils in dem oberen Kurvenzug dargestellt und die Bewegungsabfolge des Kraftstoffeinspritzventilglieds 5 in dem unteren Kurvenzug wiedergegeben. In dem oberen Kurvenzug erkennt man, daß bei einer Erregung des Piezoantriebs am Punkt 0 der Abszisse der Stößel 42 über die Zeit von ha aus einen negativen Hub zurücklegt bis bei der Höhe h0 der Schließkörper 38 an den zweiten Ventilsitz 40 gelangt ist. Über diesen Hub ergibt sich im darunterliegenden Diagramm eine Einspritzventil- gliedbewegung V entsprechend einer Voreinspritzung. Nach einer Zeitpause P, über die mit einem gewissen Nachlaufverhalten das Kraftstoffeinspritzventilglied 5 wieder in Schließstellung gelangt ist, erfolgt beispielsweise eine Teilerregung des Piezoantriebs, was den Stößel 42 auf ein Zwischenniveau hz bewegt, so daß beide Ventilsitze 36 und 40 geöffnet sind. Die resultierende Entlastung des Steuerraums 25 ergibt den Nadelhub H des Ein- spritzventilglieds 5 für die Haupteinsritzung. Bei weiterer Entregung des Piezoantriebs gelangt der Stößel 42 unter Einwirkung der Druckfeder wieder in Ausgangsstellung entsprechend den Hub ha_ Das Einspritzventilglied schließt im Nachlaufver-halten, was auch in der dynamischen Entlastung des Steuerraums 25 und die Auslegung der Drosseln 26 und 27 begründet ist.FIG. 3 shows the sequence of movements of the control valve in the upper curve and the sequence of movements of the fuel injection valve member 5 in the lower curve. The upper curve shows that when the piezo drive is excited at point 0 of the abscissa, the plunger 42 travels a negative stroke over time from h a until the closing body 38 has reached the second valve seat 40 at height h 0 . About this stroke results there is an injection valve member movement V corresponding to a pre-injection in the diagram below. After a pause P, over which the fuel injection valve member 5 has returned to the closed position with a certain lag behavior, there is, for example, partial excitation of the piezo drive, which moves the plunger 42 to an intermediate level h z , so that both valve seats 36 and 40 are open. The resulting relief of the control chamber 25 results in the needle stroke H of the injection valve member 5 for the main injection. When the piezo drive is de-energized further, the plunger 42 returns to the starting position corresponding to the stroke h a under the action of the compression spring. The injection valve member closes in the follow-up behavior, which is also due to the dynamic relief of the control chamber 25 and the design of the throttles 26 and 27.
Mit dieser erfindungsgemäßen Lösung lassen sich kleinste Einspritzmengen für einen Betrieb einer Brennkraftmaschine mit Voreinspritzung und Haupteinspritzung erzielen. Dabei hat diese Anordnung den besonderen Vorteil, daß eine Erregung des Piezoantriebs nur dann stattfindet, wenn eine Einspritzung erfolgen soll. Der Piezoantrieb ist somit über den größten Teil des Betriebs der Brennkraftmaschine stromlos und es ist eine Bereitstellung von elektrischer Energie nur für die Einspritzvorgänge erforderlich. With this solution according to the invention, the smallest injection quantities for operating an internal combustion engine with pre-injection and main injection can be achieved. This arrangement has the particular advantage that the piezo drive is only energized when an injection is to take place. The piezo drive is therefore de-energized for most of the operation of the internal combustion engine and electrical energy is only required for the injection processes.

Claims

Ansprüche Expectations
1. Kraftstoffeinspritzvorrichtung für Brennkraftmaschinen mit einer Kraftstoffhochdruckquelle, aus der ein Kraftstoffeinspritzventil (1) mit Kraftstoff versorgt wird, das ein Einspritzventilglied (5) zur Steuerung von Einspritzöffnungen (8) und einen Steuerraum (25) aufweist, der von einer beweglichen Wand (24) , die mit dem Einspritzventilglied (5) wenigstens mittelbar verbunden ist, begrenzt wird und der einen mittels einer Drossel (26) dimensionierten von einer Hochdruckquelle, vorzugsweise von der Kraftstoffhochdruckquelle kommen- den Zuflußkanal (33) , und einem Abflußkanal (28, 46) mit definiertem maximalen Abflußquerschnitt (27) zu einem Entlastungsraum (29) aufweist, an welchem Abflußkanal ein Ventilsitz (36) eines Steuerventils (31) ausgebildet ist, das ein von einer Feder (50) zum Ventil - sitz (36) hin beaufschlagtes, mit einer mit dem Ventilsitz (36) zusammenwirkenden Dichtfläche (37) versehenes Ventilglied (42, 38) aufweist, das an seinem der Dichtfläche (37) abgewandten Ende eine zum Ventilsitz (36) hin gerichtete Druckschulter (58) hat, die einen hydraulischen Druckraum (52) begrenzt, der andererseits durch eine von einem Piezoantrieb (65) betätigte bewegliche Wand (59) geschlossen wird, deren Fläche größer ist als die Fläche der Druckschulter dadurch gekenn- zeichnet, daß das Ventilglied (42, 38) einen in einer Führungsbohrung (43) geführten Stößel (42) hat, an dessen einem aus der Führungsbohrung (43) herausragenden Ende die Druckschulter (58) und an dessen anderem aus der Führungsbohrung herausragenden Ende ein1. Fuel injection device for internal combustion engines with a high-pressure fuel source, from which a fuel injection valve (1) is supplied with fuel, which has an injection valve member (5) for controlling injection openings (8) and a control chamber (25) which is supported by a movable wall (24) , which is at least indirectly connected to the injection valve member (5), and which also includes an inflow channel (33) and an outflow channel (28, 46), which are dimensioned by means of a throttle (26) from a high-pressure source, preferably from the high-pressure fuel source has a defined maximum discharge cross section (27) to a relief chamber (29), on which discharge channel a valve seat (36) of a control valve (31) is formed, which is acted upon by a spring (50) towards the valve seat (36) with a with the valve seat (36) cooperating sealing surface (37) provided valve member (42, 38) which on its sealing surface (37) at the other end has a pressure shoulder (58) directed towards the valve seat (36), which delimits a hydraulic pressure chamber (52) which, on the other hand, is closed by a movable wall (59) actuated by a piezo drive (65), the area of which is larger than that Area of the pressure shoulder shows that the valve member (42, 38) has a plunger (42) guided in a guide bore (43), at one end of which protrudes from the guide bore (43) the pressure shoulder (58) and at the other end which protrudes from the guide bore
Schließkörper (38) angeordnet ist, der in einem Ventil - räum (35) durch den Stößel (42) hin- und herbewegbar ist und auf seiner zum Steuerraum (25) hinweisenden Seite die eine, erste, mit dem einen, ersten Ventilsitz (36) zusammenwirkende Dichtfläche (37) hat und eine zweite, auf seiner der ersten Dichtfläche (37) abgewandten Seite liegende Dichtfläche (39) hat, die mit einem zweiten dem ersten Ventilsitz (36) gegenüberliegenden Ventilsitz (40) am Abflußkanal (28, 43) zusammenwirkt, wobei der Abstand zwischen dem erstenClosing body (38) is arranged, which can be moved back and forth in a valve chamber (35) by the plunger (42) and on its side facing the control chamber (25) has the one, first, with the one, first valve seat (36 ) has interacting sealing surface (37) and has a second sealing surface (39) on its side facing away from the first sealing surface (37), which has a second valve seat (40) on the outlet channel (28, 43) opposite the first valve seat (36) interacts, the distance between the first
(36) und dem zweiten Ventilsitz (40) so groß ist, das der Schließkörper (38) in einer Zwischenstellung an keinem der Ventilsitze in Anlage ist und über den Ventilraum (35) eine Verbindung zwischen den an den Ventilsitzen anschließenden Abflußkanalteilen (28, 43) hergestellt ist.(36) and the second valve seat (40) is so large that the closing body (38) is not in contact with any of the valve seats in an intermediate position and via the valve chamber (35) a connection between the outflow channel parts (28, 43 ) is manufactured.
2. Kraftstoffeinspritzvorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß der Hub des Schließkörper (38) von seiner Anlage an dem einen der Ventilsitze bis zur Anlage an dem anderen der Ventilsitze so groß ist, das unter Berücksichtigung der Stellgeschwindigkeit des Schließkörpers bei der während dieser Verstellung vom einem zum anderen der Ventilsitze entstehenden Verbin- düng der Abflußkanalteile miteinander bis zur Unterbrechung dieser Verbindung bei Anlage des Schließkörpers an einem der Ventilsitze eine eine Voreinspritzung bewirkende Entlastung des Steuerraumes erfolgt .2. Fuel injection device according to claim 1, characterized in that the stroke of the closing body (38) from its contact with one of the valve seats to the contact with the other of the valve seats is so large that taking into account the actuating speed of the closing body during this adjustment from one to the other of the valve seats connecting the discharge channel parts to each other until this connection is interrupted when the closing body is in contact Pre-injection relieves the pressure on the control chamber on one of the valve seats.
3. Kraftstoffeinspritzvorrichtung nach einem der vor- stehenden Ansprüche, dadurch gekennzeichnet, daß der erste Ventilsitz (36) als KegelVentilsitz ausgebildet ist .3. Fuel injection device according to one of the preceding claims, characterized in that the first valve seat (36) is designed as a cone valve seat.
4. Kraftstoffeinspritzvorrichtung nach Anspruch 3, dadurch gekennzeichnet, daß der zweite Ventilsitz (40) als Kegelsitz ausgebildet ist.4. Fuel injection device according to claim 3, characterized in that the second valve seat (40) is designed as a conical seat.
5. Kraftstoffeinspritzvorrichtung nach Anspruch 3, dadurch gekennzeichnet, daß der zweite Ventilsitz als Kugelsitz ausgebildet ist.5. Fuel injection device according to claim 3, characterized in that the second valve seat is designed as a ball seat.
6. Kraftstoffeinspritzvorrichtung nach Anspruch 3, dadurch gekennzeichnet, daß der zweite Ventilsitz als Flachsitz ausgebildet ist.6. Fuel injection device according to claim 3, characterized in that the second valve seat is designed as a flat seat.
7. Kraftstoffeinspritzvorrichtung nach einem der vorstehenden Ansprüche 3 bis 5, dadurch gekennzeichnet, daß der Schließkörper als Kugel ausgebildet ist.7. Fuel injection device according to one of the preceding claims 3 to 5, characterized in that the closing body is designed as a ball.
8. Kraftstoffeinspritzvorrichtung nach einem der8. Fuel injection device according to one of the
Ansprüche 1 bis 6 dadurch gekennzeichnet, daß die Führungsbohrung (43) in einen Ringraum (44) mündet, der zwischen dem aus der Führungsbohrung austretenden Stößel (42) , dem zweiten Ventilsitz (40) und der Wand des Gehäuses (1) des Einspritzventils gebildet wird und von dem der Abflußkanal (43) zum Entlastungsraum (29) abführt . Claims 1 to 6, characterized in that the guide bore (43) opens into an annular space (44) which is formed between the plunger (42) emerging from the guide bore, the second valve seat (40) and the wall of the housing (1) of the injection valve and from which the drain channel (43) leads to the relief chamber (29).
9. Kraftstoffeinspritzvorrichtung nach einem der vorstehenden Ansprüche dadurch gekennzeichnet, daß die Druckschulter (58) an einem mit dem Stößel (42) verbun- denen ersten Kolben (56) angeordnet ist, der in einer9. Fuel injection device according to one of the preceding claims, characterized in that the pressure shoulder (58) on a with the tappet (42) connected to the first piston (56) is arranged, which in a
Bohrung (57) eines zweiten in einer Zylinderbohrung (54) geführten Kolbens (53) verschiebbar ist, welcher mit seiner neben der Druckschulter (58) liegenden Stirnfläche (59) den hydraulischen Raum (52) ein- schließt und durch eine Feder (66) in Anlage an dem andererseits angeordneten Piezoantrieb (65) gehalten wird. Bore (57) of a second piston (53) which is guided in a cylinder bore (54) and which, with its end face (59) lying next to the pressure shoulder (58), encloses the hydraulic chamber (52) and is supported by a spring (66) is held in contact with the piezo drive (65) arranged on the other hand.
EP98928123A 1997-07-30 1998-04-03 Fuel injection device for internal combustion engines Expired - Lifetime EP0931215B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19732802 1997-07-30
DE19732802A DE19732802A1 (en) 1997-07-30 1997-07-30 Fuel injection device for internal combustion engines
PCT/DE1998/000944 WO1999006690A1 (en) 1997-07-30 1998-04-03 Fuel injection device for internal combustion engines

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EP0931215A1 true EP0931215A1 (en) 1999-07-28
EP0931215B1 EP0931215B1 (en) 2003-01-29

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EP98928123A Expired - Lifetime EP0931215B1 (en) 1997-07-30 1998-04-03 Fuel injection device for internal combustion engines

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US (1) US6021760A (en)
EP (1) EP0931215B1 (en)
JP (1) JP2001501272A (en)
KR (1) KR20000068640A (en)
CN (1) CN1095033C (en)
DE (2) DE19732802A1 (en)
RU (1) RU2193102C2 (en)
WO (1) WO1999006690A1 (en)

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Also Published As

Publication number Publication date
DE19732802A1 (en) 1999-02-04
EP0931215B1 (en) 2003-01-29
KR20000068640A (en) 2000-11-25
RU2193102C2 (en) 2002-11-20
CN1095033C (en) 2002-11-27
WO1999006690A1 (en) 1999-02-11
DE59807062D1 (en) 2003-03-06
CN1236417A (en) 1999-11-24
US6021760A (en) 2000-02-08
JP2001501272A (en) 2001-01-30

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