EP1068445A1 - Fuel injection device for internal combustion engines - Google Patents

Fuel injection device for internal combustion engines

Info

Publication number
EP1068445A1
EP1068445A1 EP99964367A EP99964367A EP1068445A1 EP 1068445 A1 EP1068445 A1 EP 1068445A1 EP 99964367 A EP99964367 A EP 99964367A EP 99964367 A EP99964367 A EP 99964367A EP 1068445 A1 EP1068445 A1 EP 1068445A1
Authority
EP
European Patent Office
Prior art keywords
valve
pressure
fuel
injection
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
EP99964367A
Other languages
German (de)
French (fr)
Other versions
EP1068445B1 (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 EP1068445A1 publication Critical patent/EP1068445A1/en
Application granted granted Critical
Publication of EP1068445B1 publication Critical patent/EP1068445B1/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
    • 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
    • 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
    • F02M45/08—Injectors peculiar thereto
    • 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
    • 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
    • F02M63/0031—Valves characterized by the type of valves, e.g. special valve member details, valve seat details, valve housing details
    • F02M63/004—Sliding valves, e.g. spool valves, i.e. whereby the closing member has a sliding movement along a seat for opening and closing
    • 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
    • F02M63/0031—Valves characterized by the type of valves, e.g. special valve member details, valve seat details, valve housing details
    • F02M63/0045—Three-way 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
    • F02M63/0012—Valves
    • F02M63/0059—Arrangements of valve actuators
    • F02M63/0068—Actuators specially adapted for partial and full opening of the 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
    • 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

Definitions

  • the invention is based on a fuel injection device for internal combustion engines according to the preamble of claim 1.
  • a fuel injection device for internal combustion engines according to the preamble of claim 1.
  • the fuel injection valve member supplied by a high-pressure fuel source is controlled by various hydraulic forces acting on it in the opening and closing directions. It has an injection valve member for controlling an injection opening and, on its side facing away from the injection opening, includes a control chamber which is supplied with high fuel pressure by a high-pressure fuel source via a throttled inflow channel and which can be relieved via the control valve, which is actuated by a piezo actuator , so that in this case the injection valve member is opened by the hydraulic pressure acting on the pressure shoulder of the injection valve member and in the absence of hydraulic high pressure in the control chamber.
  • control valve is arranged in a drain channel of the control chamber.
  • Fuel injection device still be provided a connection to the pressure space delimited by the pressure shoulder of the injection valve member, which is constantly kept under high pressure.
  • This known device is complex for the reason described, since in addition to the multiple connection between the high-pressure fuel source to the control chamber on the one hand and to the pressure chamber on the other hand, the inlet and blue cross sections to the control chamber and the pressure-exposed areas on the injection valve member must be coordinated exactly with one another.
  • the fuel injection device according to the invention with the characterizing features of claim 1 has the
  • the injection valve member of the fuel injection valve can be opened quickly and exactly above the piezo drive for a pre-injection with simple means, then closed again in order to then be opened for the subsequent main injection. It is of essential advantage that the control valve member only has to be moved back and forth for the entire process. In particular, very short high-pressure supply times can be achieved in order to achieve the pre-injection via the short phase of opening both valve seats on the control valve while the control valve member is moving in the same direction. In a particularly advantageous manner, large opening strokes of the control valve member can be achieved by means of a hydraulic transmission, despite the small working strokes of a piezo actuator.
  • a further advantageous embodiment of the invention is that, according to claim 3, the high fuel pressure coming from the high-pressure fuel source when the control valve member is closed brings about a force equalization on the control valve member, since the same areas in both
  • the area ratio of the areas exposed to pressure acting on the control valve member can be selected so that the control valve member from the high pressure prevailing in the recess
  • High pressure fuel source in the direction of opening is slightly more loaded than in the closing direction.
  • the closing takes place by resetting spring forces on the control valve member.
  • the pressurization of the control valve member according to claim 5 is selected so that the supply of the pressure line to the valve chamber takes place coaxially with the valve tappet, so that when the valve head is in contact with its second valve seat, the connection between the high-pressure fuel source and the valve chamber or to the pressure chamber of the fuel injection valve is closed is.
  • the control valve member is acted upon by relatively large opening forces, the valve tappet bore is only acted on by the low fuel, so that the leakage losses of the control valve are low.
  • the pressurization on the valve lifter or the latter The leading valve tappet bore occurs only during the connection of the pressure line to the pressure chamber, that is to say during the injection phase of the fuel injection device.
  • FIG. 1 shows a schematic illustration of a fuel injection device with fuel supply from a high-pressure fuel reservoir and a fuel injection valve of a first exemplary embodiment
  • FIG. 2 shows the stroke profiles of the fuel injection valve and control valve member of the exemplary embodiment according to FIG. 1
  • FIG. 3 shows a modification of the exemplary embodiment according to FIG. 1 with interchanged connections of the pressure line that leads from the high-pressure fuel reservoir to the fuel injection valve.
  • a fuel injection device with which a large one at high injection pressures with little effort
  • a variation of the fuel injection with respect to the injection quantity and the injection timing is possible by means of a so-called common rail system.
  • This provides a different type of high-pressure fuel source, from which a fuel injection can take place than is specified in the usual high-pressure fuel injection pumps.
  • a high-pressure fuel reservoir 1 is provided as the high-pressure fuel source, which is supplied with fuel by a high-pressure fuel delivery pump 2 from a fuel reservoir 4, which is brought to the injection pressure.
  • the pressure in the high-pressure fuel reservoir is detected by a pressure sensor 6 and fed as a signal to an electrical control device 8, which controls the pressure in the high-pressure fuel reservoir via a pressure control valve 5.
  • the control device also controls the opening and closing of fuel injection valves 9, which are supplied for the injection of fuel from the high-pressure fuel reservoir.
  • a pressure line with the partial branches 10a, 10b leads from the high-pressure fuel accumulator 1 to a pressure chamber 11 in the fuel injection valve, which pressure chamber 11 surrounds the end of the fuel injection valve member 12 in a ring shape and penetrates up to a valve seat 13.
  • the injection valve member has in the area of the pressure chamber 11 a pressure shoulder 14 which is loaded by the pressure of the pressure chamber 11 in the opening direction of the injection valve member 12 against a closing spring 15 acting on the rear side of the injection valve member. If the hydraulic forces on the pressure shoulder 14 exceed the closing forces of the closing spring 15, the valve member lifts off with its sealing surface 16 from the valve seat 13 and establishes the connection between the pressure chamber 11 and the injection openings 17 so that the fuel injection can take place.
  • This fuel injection is controlled by supplying high-pressure fuel to the pressure chamber 11 via the pressure line 10a, 10b.
  • a control valve 18 is provided in this pressure line for controlling it.
  • This has a control valve member 20, with a valve tappet 21 which is guided in a valve tappet bore 22 and has at its end a valve head 23 which is movable within a valve chamber 24.
  • this carries a spring plate 26, between which and the housing
  • Closing spring 27 is clamped, which strives to bring the valve head with a valve head sealing surface 29 located on one side thereof to a correspondingly conical first valve seat 30.
  • the first valve seat 30 is located at the transition between the valve chamber 24 with a larger diameter to the tappet bore 22.
  • valve seat 31 On the side of the valve chamber 24 opposite the first valve seat 30 there is a second, likewise conical valve seat 31 at the outlet of the part 10b of the pressure line from the valve chamber 24, which pressure line part 10b leads to the pressure chamber 11.
  • a second valve head sealing surface 32 cooperates on the valve head 37, so that the connection between the valve chamber 24 and the pressure line 10b is closed when the control valve member 20 is moved from the first valve seat against the force of the closing spring 27 to the second valve seat 31.
  • the tappet 21 has an annular recess 33, which together with the valve head 23 resting on the first valve seat 30 the tappet bore 22 includes an annular space 34.
  • the pressure line part 10a which leads from the high-pressure fuel reservoir 1, opens into this. If the control valve member 20 is in the closed position shown in FIG. 1, the connection between the high-pressure fuel reservoir 1 and the pressure chamber 11 is closed. The forces acting on the control valve member 20 due to the high pressure loading of the annular space 34 are substantially balanced in the axial direction of the control valve member.
  • the pressurized surface on the control valve member 20, which points in the direction of the valve chamber 24, can be slightly larger than the surface acting on the tappet in the direction of the spring plate 24.
  • the closing spring 27 applies the closing force necessary for securely closing the control valve 18, which is greater than the resulting hydraulic force acting in the opening direction. This has the advantage that low actuation forces are necessary for the control valve member 20.
  • the control valve member 20 is actuated by means of a piezo actuator, the actuator 36 of which is partially shown in FIG. 1.
  • the actuator 36 delimits, with its end face 37, part of a closed transmission space 38, to which an end face 39 of a tappet actuating piston 40 also adjoins, which is guided tightly in a guide bore 41 which connects coaxially to the valve tappet bore 22.
  • the end face 37 of the actuator 36 is substantially larger than the end face 39 of the tappet actuating piston 40.
  • the piezo actuator is excited by the control device 8 and the actuator 36 is moved into the transmission space 38, the small stroke of the Actuator 36 enlarged by the area ratio of the end faces 37 and 39 into a larger stroke of the tappet actuating piston 40, which correspondingly moves the control valve member 20 to a relatively large opening stroke when it contacts the end of the valve tappet 21.
  • FIGS. 2a and 2b The movements of the control valve member 20 and the injection valve member 12 one above the other are shown in FIGS. 2a and 2b.
  • the piezo is excited in such a way that the valve head lifts off from its contact with the first valve seat 30 until it comes to contact with the second valve seat 31.
  • the two sub-lines 10a and 10b of the pressure line are connected to one another via the valve chamber 24, so that high fuel pressure can reach the pressure chamber 11 and cause the injection valve member 12 to rise there.
  • FIG. 2a with the stroke V.
  • the corresponding stroke of the control valve member is shown in Figure 2b over the area V s .
  • the connection of the pressure line parts 10a and 10b of the pressure line is interrupted again, which leads to a drop in the injection V according to FIG. 2a.
  • the control valve member 20 is then returned by appropriate activation of the piezo actuator in such a way that the valve head 23 assumes a stroke h Hs , at which it is spaced both from the first valve seat 30 and from the second valve seat 31 and thus the connection of the sub-lines 10a and 10b of the pressure line.
  • the main injection H then takes place over the duration of the control valve member remaining in this position.
  • the control valve member 20 becomes the end of the main injection completely returned so that the first
  • Valve head sealing surface 29 in turn close to the first valve seat
  • control valve member 20 In this embodiment of the control valve member, only small switching forces are required for the control valve member 20, since it is essentially force-balanced between the injections in the starting position shown in FIG. 1 when subjected to high pressure. However, the high fuel pressure is present on the valve tappet 21, so that leakage losses along the valve tappet bore 22 can occur. A corresponding procedure must be ensured.
  • control valve is used in the essentially identical configuration as in Figure 1.
  • the only difference here is that the pressure line with its pressure line part 10a does not open into the annular space 34, but opens into the valve space 24 at the second valve seat.
  • the pressure line part 10b of the pressure line then points from the annular space 34.
  • the control valve can be controlled in the same way as in the first exemplary embodiment. In the starting position, the valve head 23 rests with its first valve head sealing surface 29 on the first valve seat 30, so that the valve chamber 24 is exposed to the high pressure supplied by the pressure line 10a. This pressure keeps the valve closing member 20 in the closed position.
  • the control valve member 20 is moved as before from the first valve seat 30 to the second valve seat 31 and the connection between the pressure line parts 10a and 10b is established briefly, over a time that is sufficient Trigger pre-injection V according to Figure 2a.
  • this pre-injection is then ended and, after a pause P, the control valve member 20 is brought into an intermediate position between the two valve seats 30 and 31, as before, for carrying out the main injection H. Then this return movement is continued until the Valve head 23 rests against the first valve seat 30 and the main injection ends.
  • the amount of leakage along the valve tappet 21 is reduced, since the high fuel pressure is only applied to it during the injection phases.
  • larger actuation forces of the control valve member are required, but this can easily be achieved by a piezo actuator with hydraulic transmission.
  • the hydraulic ratio advantageously enables the large opening strokes h vs.

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

Abstract

Disclosed is a fuel injection device for internal combustion engines. Said device supplies fuel from a high pressure fuel source (1) to fuel injection valves (9) controlled by a control device (10). The fuel injection device has an injection valve member (12) that is impinged upon by the supplied high pressure fuel via an exposed annular area (14) and that can be opened for effecting injection. The fuel is supplied by means of a pressure line (10a, 10b). The passage of fuel is controlled by a control valve (20) whose control valve is movable in a valve chamber (24) between two valve seats (30, 31) and which controls the connection between the high pressure fuel source (1) and the fuel injection valve (9) for effecting a preinjection and a main injection.

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 solchen, durch die DE 196 24 001 AI bekannten Kraftstoffeinspritzeinrichtung wird das von einer Kraftstoffhochdruckquelle versorgte Kraftstoffeinspritzventilglied durch verschiedene an diesem in Öffnungs- und Schließrichtung angreifende hydraulischen Kräfte gesteuert. Es weist ein Einspritzventilglied zur Steuerung einer Einspritzöffnung auf und schließt auf seiner der Einspritzöffnung abgewandten Seite einen Steuerraum ein, der über einen gedrosselten Zuflußkanal von einer Kraftstoffhochdruckquelle mit hohem Kraftstoffdruck versorgt wird und der über das Steuerventil, das von einem Piezoaktor betätigt wird, entlastet werden kann, so daß in diesem Fall durch den an der Druckschulter des Einspritzventilglieds angreifenden hydraulischen Druck und bei dem im Steuerraum fehlenden hydraulischen Hochdruck das Einspritzventilglied geöffnet wird. Umgekehrt wird beim Verschluß des Steuerraums der hohe Kraftstof druck im Steuerraum wieder aufgebaut und das Einspritzventilglied wieder in Schließstellung gebracht. Bei der bekannten Kraftstoffeinspritzeinrichtung ist das Steuerventil in einem Abflußkanal des Steuerraums angeordnet. Zusätzlich zu der Verbindung vom Hochdruckspeicher zum Steuerraum muß bei der bekanntenThe invention is based on a fuel injection device for internal combustion engines according to the preamble of claim 1. In such a fuel injection device known from DE 196 24 001 A1, the fuel injection valve member supplied by a high-pressure fuel source is controlled by various hydraulic forces acting on it in the opening and closing directions. It has an injection valve member for controlling an injection opening and, on its side facing away from the injection opening, includes a control chamber which is supplied with high fuel pressure by a high-pressure fuel source via a throttled inflow channel and which can be relieved via the control valve, which is actuated by a piezo actuator , so that in this case the injection valve member is opened by the hydraulic pressure acting on the pressure shoulder of the injection valve member and in the absence of hydraulic high pressure in the control chamber. Conversely, when the control room is closed, the high fuel pressure in the control room is built up again brought the injection valve member back into the closed position. In the known fuel injection device, the control valve is arranged in a drain channel of the control chamber. In addition to the connection from the high pressure accumulator to the control room, the known must
Kraftstoffeinspritzvorrichtung noch eine Verbindung zu dem von der Druckschulter des Einspritzventilglieds begrenzten Druckraum bereitgestellt werden, der ständig unter Hochdruck gehalten wird. Diese bekannte Einrichtung ist aus dem geschilderten Grund aufwendig, da neben der mehrfachen Verbindung zwischen der Kraftstoffhochdruckquelle zum Steuerraum einerseits und zum Druckraum andererseits auch die Zu- und blaufcruerschnitte zum Steuerraum und die druckausgesetzten Flächen am Einspritzventilglied exakt aufeinander abgestimmt werden müssen.Fuel injection device still be provided a connection to the pressure space delimited by the pressure shoulder of the injection valve member, which is constantly kept under high pressure. This known device is complex for the reason described, since in addition to the multiple connection between the high-pressure fuel source to the control chamber on the one hand and to the pressure chamber on the other hand, the inlet and blue cross sections to the control chamber and the pressure-exposed areas on the injection valve member must be coordinated exactly with one another.
Vorteile der ErfindungAdvantages of the invention
Die erfindungsgemäße Kraftstoffeinspritzvorrichtung mit den kennzeichnenden Merkmalen des Patentanspruchs 1 hat denThe fuel injection device according to the invention with the characterizing features of claim 1 has the
Vorteil, daß mit einfachen Mitteln das Einspritzventilglied des Kraftstoffeinspritzventils schnell und exakt über dem Piezoantrieb für eine Voreinspritzung geöffnet werden kann, danach wieder geschlossen wird, um anschließend für die nachfolgende Haupteinspritzung geöffnet zu werden. Dabei ist es von wesentlichem Vorteil, daß das Steuerventilglied für den gesamten Vorgang nur einmal hin- und herbewegt werden muß. Insbesondere lassen sich über die kurze Phase der Öffnung beider Ventilsitze am Steuerventil bei durchgehender gleichgerichteten Bewegung des Steuerventilgliedes sehr kurze Hochdruckzufuhrzeiten zur Erzielung der Voreinspritzung erreichen. In besonders vorteilhafter Weise können gemäß Patentanspruch 2 trotz geringer Arbeitshübe eines Piezoaktors mittels einer hydraulischen Übersetzung große Öffnungshübe des Steuerventilglieds erzielt werden. Eine weitere vorteilhafte Ausgestaltung der Erfindung besteht darin, daß gemäß Patentanspruch 3 der bei geschlossenem Steuerventilglied an diesem anstehende hohe, von der Kraftstoffhochdruckquelle kommende Kraftstoffdruck ein Kräfteausgleich am Steuerventilglied bewirkt, da gleiche Flächen in beidenAdvantage that the injection valve member of the fuel injection valve can be opened quickly and exactly above the piezo drive for a pre-injection with simple means, then closed again in order to then be opened for the subsequent main injection. It is of essential advantage that the control valve member only has to be moved back and forth for the entire process. In particular, very short high-pressure supply times can be achieved in order to achieve the pre-injection via the short phase of opening both valve seats on the control valve while the control valve member is moving in the same direction. In a particularly advantageous manner, large opening strokes of the control valve member can be achieved by means of a hydraulic transmission, despite the small working strokes of a piezo actuator. A further advantageous embodiment of the invention is that, according to claim 3, the high fuel pressure coming from the high-pressure fuel source when the control valve member is closed brings about a force equalization on the control valve member, since the same areas in both
Bewegungsrichtungen des Steuerventilglieds gleich groß sind. Gemäß Patentanspruch 4 kann dabei das Flächenverhältnis der am Steuerventilglied wirkenden Druck ausgesetzten Flächen so gewählt werden, daß das Steuerventilglied vom in der Ausnehmung herrschenden Hochdruck derDirections of movement of the control valve member are the same size. According to claim 4, the area ratio of the areas exposed to pressure acting on the control valve member can be selected so that the control valve member from the high pressure prevailing in the recess
Kraftstoffhochdruckquelle in Öffnungsriehtung geringfügig mehr belastet wird als in Schließrichtung. Das Schließen erfolgt dabei durch rückstellende Federkräfte am Steuerventilglied.High pressure fuel source in the direction of opening is slightly more loaded than in the closing direction. The closing takes place by resetting spring forces on the control valve member.
In einer letzten Ausgestaltung schließlich ist die Druckbeaufschlagung des Steuerventilglieds gemäß Patentanspruch 5 so gewählt, daß der Zulauf der Druckleitung zum Ventilraum koaxial zum Ventilstößel erfolgt, so daß bei an seinem zweiten Ventilsitz anliegenden Ventilkopf die Verbindung zwischen Kraftstoffhochdruckquelle und Ventilraum bzw. zum Druckraum des Kraftstoffeinspritzventils geschlossen ist. Dabei wird zwar das Steuerventilglied von relativ großen Öffnungskräften beaufschlagt, doch wird die Ventilstößel- bohrung nur vom niedrigen Kraftstoff beaufschlagt, so daß die Leckverluste des Steuerventils gering sind. Die Druckbeaufschlagung auf den Ventilstößel bzw. die diesen führenden Ventilstößelbohrung erfolgt dabei lediglich während der Verbindung der Druckleitung zum Druckraum, das heißt während der Einspritzphase der Kraftstoffeinspritz- vorrichtung .In a last embodiment, finally, the pressurization of the control valve member according to claim 5 is selected so that the supply of the pressure line to the valve chamber takes place coaxially with the valve tappet, so that when the valve head is in contact with its second valve seat, the connection between the high-pressure fuel source and the valve chamber or to the pressure chamber of the fuel injection valve is closed is. Although the control valve member is acted upon by relatively large opening forces, the valve tappet bore is only acted on by the low fuel, so that the leakage losses of the control valve are low. The pressurization on the valve lifter or the latter The leading valve tappet bore occurs only during the connection of the pressure line to the pressure chamber, that is to say during the injection phase of the fuel injection device.
Zeichnungdrawing
Zwei Ausführungsbeispiele der Erfindung sind in der Zeichnung dargestellt und werden in der nachfolgenden Beschreibung näher erläutert . Es zeigen Figur 1 eine schematische Darstellung einer Kraftstoffeinspritzvorrichtung mit Kraftstoffversorgung aus einem Kraftstoffhochdruckspeicher und einem Kraftstoffeinspritzventil eines ersten Ausführungsbeispiels, Figur 2 eine Darstellung der Hubverläufe von Kraftstoffeinspritzventil und Steuerventilglied des Ausführungsbeispiels nach Figur 1 und Figur 3 eine Abwandlung des Ausführungsbeispiels nach Figur 1 mit vertauschten Anschlüssen von der Druckleitung, die vom Kraftstoffhochdruckspeicher zum Kraftstoffeinspritzventil führt.Two embodiments of the invention are shown in the drawing and are explained in more detail in the following description. 1 shows a schematic illustration of a fuel injection device with fuel supply from a high-pressure fuel reservoir and a fuel injection valve of a first exemplary embodiment, FIG. 2 shows the stroke profiles of the fuel injection valve and control valve member of the exemplary embodiment according to FIG. 1, and FIG. 3 shows a modification of the exemplary embodiment according to FIG. 1 with interchanged connections of the pressure line that leads from the high-pressure fuel reservoir to the fuel injection valve.
Beschreibung der AusführungsbeispieleDescription of the embodiments
Eine Kraftstoffeinspritzeinrichtung, mit der bei hohen Einspritzdrücken aber mit geringem Aufwand eine großeA fuel injection device with which a large one at high injection pressures with little effort
Variation der Kraftstoffeinspritzung bezüglich Einspritzmenge und Einspritzzeitpunkt möglich ist, wird durch ein sogenanntes Common Rail System verwirklicht. Dies stellt eine andere Art von Kraftstoffhochdruckquelle zur Verfügung, aus der eine Kraftstoffeinspritzung erfolgen kann als dies bei den üblichen Kraftstoffhochdruckeinspritzpumpen vorgegeben ist . Bei dem in Figur 1 dargestellten Common Rail Einspritzsystem ist als Kraftstoffhochdruckquelle ein Kraftstoff- hochdruckspeicher 1 vorgesehen, der von einer Kraftstoff- hochdruckförderpumpe 2 aus einem Kraftstoffvorratsbehälter 4 mit Kraftstoff versorgt wird, der auf Einspritzdruck gebracht ist . Der Druck im Kraftstoffhochdruckspeicher wird von einem Drucksensor 6 erfaßt und als Signal einer elektrischen Steuereinrichtung 8 zugeführt, die über ein Drucksteuerventil 5 dem Druck im Kraftstoffhochdruckspeicher steuert . Die Steuereinrichtung steuert ferner auch das Öffnen und Schließen von Kraftstoffeinspritzventilen 9, die zur Einspritzung von Kraftstoff aus dem Kraftstoffhochdruckspeicher versorgt werden.A variation of the fuel injection with respect to the injection quantity and the injection timing is possible by means of a so-called common rail system. This provides a different type of high-pressure fuel source, from which a fuel injection can take place than is specified in the usual high-pressure fuel injection pumps. In the common rail injection system shown in FIG. 1, a high-pressure fuel reservoir 1 is provided as the high-pressure fuel source, which is supplied with fuel by a high-pressure fuel delivery pump 2 from a fuel reservoir 4, which is brought to the injection pressure. The pressure in the high-pressure fuel reservoir is detected by a pressure sensor 6 and fed as a signal to an electrical control device 8, which controls the pressure in the high-pressure fuel reservoir via a pressure control valve 5. The control device also controls the opening and closing of fuel injection valves 9, which are supplied for the injection of fuel from the high-pressure fuel reservoir.
Dazu führt vom Kraftstoffhochdruckspeicher 1 eine Druckleitung mit den Teilzweigen 10a, 10b zu einem Druckraum 11 im Kraftstoffeinspritzventil, welcher Druckraum 11 das Ende des Kraftstoffeinspritzventilgliedes 12 ringförmig umgibt und bis zu einem Ventilsitz 13 vordringt. Das Einspritzventilglied hat dabei im Bereich des Druckraumes 11 eine Druckschulter 14, die durch den Druck des Druckraumes 11 in Öffnungsrichtung des Einspritzventilgliedes 12 entgegen einer auf der Rückseite des Einspritzventilgliedes angreifenden Schließfeder 15 belastet wird. Übersteigen die hydraulischen Kräfte an der Druckschulter 14 die Schließkräfte der Schließfeder 15, so hebt das Ventilglied mit seiner Dichtfläche 16 vom Ventilsitz 13 ab und stellt die Verbindung zwischen Druckraum 11 und Einspritzöffnungen 17 her, so daß die Kraftstoffeinspritzung erfolgen kann. Gesteuert wird diese Kraftstoffeinspritzung durch die Zufuhr von Kraftstoffhochdruck über die Druckleitung 10a, 10b zum Druckraum 11. Zu deren Steuerung ist in dieser Druckleitung ein Steuerventil 18 vorgesehen. Dieses weist ein Steuerventilglied 20 auf, mit einem Ventilstößel 21, der in einer Ventilstößelbohrung 22 geführt ist und an seinem Ende einen Ventilkopf 23 aufweist, der innerhalb eines Ventilraumes 24 bewegbar ist. An dem dem Ventilkopf 23 gegenüberliegenden Ende des Stößel 24 trägt dieser einen Federteller 26, zwischen dem und dem Gehäuse eineFor this purpose, a pressure line with the partial branches 10a, 10b leads from the high-pressure fuel accumulator 1 to a pressure chamber 11 in the fuel injection valve, which pressure chamber 11 surrounds the end of the fuel injection valve member 12 in a ring shape and penetrates up to a valve seat 13. The injection valve member has in the area of the pressure chamber 11 a pressure shoulder 14 which is loaded by the pressure of the pressure chamber 11 in the opening direction of the injection valve member 12 against a closing spring 15 acting on the rear side of the injection valve member. If the hydraulic forces on the pressure shoulder 14 exceed the closing forces of the closing spring 15, the valve member lifts off with its sealing surface 16 from the valve seat 13 and establishes the connection between the pressure chamber 11 and the injection openings 17 so that the fuel injection can take place. This fuel injection is controlled by supplying high-pressure fuel to the pressure chamber 11 via the pressure line 10a, 10b. A control valve 18 is provided in this pressure line for controlling it. This has a control valve member 20, with a valve tappet 21 which is guided in a valve tappet bore 22 and has at its end a valve head 23 which is movable within a valve chamber 24. At the end of the plunger 24 opposite the valve head 23, this carries a spring plate 26, between which and the housing
Schließfeder 27 eingespannt ist, die bestrebt ist, den Ventilkopf mit einer auf der einen Seite desselben befindlichen Ventilkopfdichtfläche 29 an einen entsprechend konisch ausgestalteten ersten Ventilsitz 30 zu bringen. Der erste Ventilsitz 30 befindet sich am Übergang zwischen dem im Durchmesser weiteren Ventilraum 24 zur Stößelbohrung 22.Closing spring 27 is clamped, which strives to bring the valve head with a valve head sealing surface 29 located on one side thereof to a correspondingly conical first valve seat 30. The first valve seat 30 is located at the transition between the valve chamber 24 with a larger diameter to the tappet bore 22.
Auf der dem ersten Ventilsitz 30 gegenüberliegenden Seite des Ventilraums 24 befindet sich ein zweiter, ebenfalls kegelförmiger Ventilsitz 31 am Austritt des Teils 10b der Druckleitung aus dem Ventilraum 24, welcher Druckleitungsteil 10b zum Druckraum 11 führt. Mit diesem zweiten Ventilsitz 31 wirkt eine zweite Ventilkopfdichtfläche 32 am Ventilkopf 37 zusammen, so daß die Verbindung zwischen dem Ventilraum 24 und der Druckleitung 10b geschlossen ist, wenn das Steuerventilglied 20 vom ersten Ventilsitz entgegen der Kraft der Schließfeder 27 zum zweiten Ventilsitz 31 bewegt wird.On the side of the valve chamber 24 opposite the first valve seat 30 there is a second, likewise conical valve seat 31 at the outlet of the part 10b of the pressure line from the valve chamber 24, which pressure line part 10b leads to the pressure chamber 11. With this second valve seat 31, a second valve head sealing surface 32 cooperates on the valve head 37, so that the connection between the valve chamber 24 and the pressure line 10b is closed when the control valve member 20 is moved from the first valve seat against the force of the closing spring 27 to the second valve seat 31.
Anschließend an die erste Ventilkopfdichtfläche 29 weist der Stößel 21 eine ringförmige Ausnehmung 33 auf, die bei am ersten Ventilsitz 30 anliegendem Ventilkopf 23 zusammen mit der Stößelbohrung 22 einen Ringraum 34 einschließt. In diesen mündet der Druckleitungsteil 10a, der vom Kraftstoffhochdruckspeicher 1 herführt. Ist das Steuerventilglied 20 in der in Figur 1 gezeigten geschlossenen Stellung, so ist die Verbindung zwischen Kraftstoffhochdruckspeicher 1 und Druckraum 11 verschlossen. Die aufgrund der Hochdruckbeaufschlagung des Ringraumes 34 auf das Steuerventilglied 20 wirkenden Kräfte sind in Achsrichtung des Steuerventilglieds im wesentlichen ausgeglichen. Durch entsprechende Gestaltung von erstem Ventilsitz 30 und erster Ventilkopfdichtfläche 29 kann die druckbeaufschlagte Fläche am Steuerventilglied 20, die in Richtung Ventilraum 24 weist, geringfügig größer sein, als die in Richtung Federteller 24 wirkende Fläche am Stößel. Die Schließfeder 27 bringt die zum sicheren Verschließen des Steuerventils 18 notwendige Schließkraft auf, die größer ist als die in Öffnungsrichtung wirkende resultierende hydraulische Kraft. Dies hat den Vorteil, daß geringe Betätigungskräfte für das Steuerventilglied 20 notwendig sind.Following the first valve head sealing surface 29, the tappet 21 has an annular recess 33, which together with the valve head 23 resting on the first valve seat 30 the tappet bore 22 includes an annular space 34. The pressure line part 10a, which leads from the high-pressure fuel reservoir 1, opens into this. If the control valve member 20 is in the closed position shown in FIG. 1, the connection between the high-pressure fuel reservoir 1 and the pressure chamber 11 is closed. The forces acting on the control valve member 20 due to the high pressure loading of the annular space 34 are substantially balanced in the axial direction of the control valve member. By appropriate design of the first valve seat 30 and the first valve head sealing surface 29, the pressurized surface on the control valve member 20, which points in the direction of the valve chamber 24, can be slightly larger than the surface acting on the tappet in the direction of the spring plate 24. The closing spring 27 applies the closing force necessary for securely closing the control valve 18, which is greater than the resulting hydraulic force acting in the opening direction. This has the advantage that low actuation forces are necessary for the control valve member 20.
Die Betätigung des Steuerventilglieds 20 erfolgt mittels eines Piezoaktors, dessen Stellglied 36 teilweise in Figur 1 dargestellt ist. Das Stellglied 36 begrenzt mit seiner Stirnseite 37 einen Teil eines geschlossenen Übertragungs- raumes 38, an den ferner eine Stirnseite 39 eines Stößelbetätigungskolbens 40 angrenzt, der dicht in einer Führungsbohrung 41 geführt ist, die sich koaxial an die Ventil- stδßelbohrung 22 anschließt. Die Stirnfläche 37 des Stellglieds 36 ist dabei wesentlich größer als die Stirnseite 39 des Stößelbetätigungskolbens 40. Wird der Piezoaktor durch die Steuereinrichtung 8 erregt und das Stellglied 36 in den Übertragungsraum 38 hineinbewegt, so wird der kleine Hub des Stellglieds 36 um das Flächenverhältnis der Stirnseiten 37 und 39 in einen größeren Hub des Stößelbetätigungskolbens 40 vergrößert, der entsprechend am Ende des Ventilstößels 21 anliegend das Steuerventilglied 20 zu einem relativ großen Öffnungshub bewegt .The control valve member 20 is actuated by means of a piezo actuator, the actuator 36 of which is partially shown in FIG. 1. The actuator 36 delimits, with its end face 37, part of a closed transmission space 38, to which an end face 39 of a tappet actuating piston 40 also adjoins, which is guided tightly in a guide bore 41 which connects coaxially to the valve tappet bore 22. The end face 37 of the actuator 36 is substantially larger than the end face 39 of the tappet actuating piston 40. If the piezo actuator is excited by the control device 8 and the actuator 36 is moved into the transmission space 38, the small stroke of the Actuator 36 enlarged by the area ratio of the end faces 37 and 39 into a larger stroke of the tappet actuating piston 40, which correspondingly moves the control valve member 20 to a relatively large opening stroke when it contacts the end of the valve tappet 21.
In der Figur 2a und Figur 2b sind die Bewegungen des Steuerventilglieds 20 und des Einspritzventilglieds 12 übereinander dargestellt . Zur Durchführung einer Vorein- spritzung wird der Piezo so erregt, daß der Ventilkopf von seiner Anlage am ersten Ventilsitz 30 abhebt, bis er zur Anlage am zweiten Ventilsitz 31 kommt. Über diese Bewegung hinweg sind die beiden Teilleitungen 10a und 10b der Druckleitung über den Ventilraum 24 miteinander verbunden, so daß Kraftstoffhochdruck in den Druckraum 11 gelangen kann und dort eine Erhebung des Einspritzventilglieds 12 bewirkt. Dies ist in der Figur 2a mit dem Hub V dargestellt. Der entsprechende Hub des Steuerventilglieds ist in Figur 2b über dem Bereich Vs dargestellt. Am Ende dieses Hubes, das in dem Diagramm mit hvs bezeichnet ist, ist die Verbindung der Druckleitungsteilen 10a und 10b der Druckleitung wieder unterbrochen, was zum Abfall der Einspritzung V gemäß Figur 2a führt . Nach einer Spritzpause P wird dann das Steuerventilglied 20 durch entsprechende Ansteuerung des Piezoaktors derart zurückgeführt, daß der Ventilkopf 23 einen Hub hHs einnimmt, bei dem er sowohl vom ersten Ventilsitz 30 als auch vom zweiten Ventilsitz 31 beabstandet ist und somit die Verbindung der Teilleitungen 10a und 10b der Druckleitung hergestellt hat. Über die Dauer des Verharrens des Steuerventilglieds in dieser Stellung erfolgt dann die Haupteinspritzung H. Schließlich wird zur Beendigung der Haupteinspritzung das Steuerventilglied 20 wieder ganz zurückgeführt, so daß die ersteThe movements of the control valve member 20 and the injection valve member 12 one above the other are shown in FIGS. 2a and 2b. To carry out a pre-injection, the piezo is excited in such a way that the valve head lifts off from its contact with the first valve seat 30 until it comes to contact with the second valve seat 31. Over this movement, the two sub-lines 10a and 10b of the pressure line are connected to one another via the valve chamber 24, so that high fuel pressure can reach the pressure chamber 11 and cause the injection valve member 12 to rise there. This is shown in FIG. 2a with the stroke V. The corresponding stroke of the control valve member is shown in Figure 2b over the area V s . At the end of this stroke, which is designated h vs in the diagram, the connection of the pressure line parts 10a and 10b of the pressure line is interrupted again, which leads to a drop in the injection V according to FIG. 2a. After a pause in spraying P, the control valve member 20 is then returned by appropriate activation of the piezo actuator in such a way that the valve head 23 assumes a stroke h Hs , at which it is spaced both from the first valve seat 30 and from the second valve seat 31 and thus the connection of the sub-lines 10a and 10b of the pressure line. The main injection H then takes place over the duration of the control valve member remaining in this position. Finally, the control valve member 20 becomes the end of the main injection completely returned so that the first
Ventilkopfdichtfläche 29 wiederum dicht am ersten VentilsitzValve head sealing surface 29 in turn close to the first valve seat
30 zur Anlage kommt.30 comes to the plant.
Bei dieser Ausgestaltung des Steuerventilglieds werden nur geringe Schaltkräfte für das Steuerventilglied 20 erforderlich, da es bei Hochdruckbeaufschlagung in der in Figur 1 gezeigten Ausgangsstellung zwischen den Einspritzungen im wesentlichen kraftausgeglichen ist. Allerdings liegt der hohe Kraftstoffdruck am Ventilstδßel 21 an, so daß es zu Leckverlusten entlang der Ventilstößelbohrung 22 kommen kann. Es ist für einen entsprechenden Ablauf Sorge zu tragen.In this embodiment of the control valve member, only small switching forces are required for the control valve member 20, since it is essentially force-balanced between the injections in the starting position shown in FIG. 1 when subjected to high pressure. However, the high fuel pressure is present on the valve tappet 21, so that leakage losses along the valve tappet bore 22 can occur. A corresponding procedure must be ensured.
In Figur 3 findet das Steuerventil in der im wesentlichen gleichartigen Ausgestaltung wie bei Figur 1 Anwendung. Unterschiedlich ist hier lediglich, daß die Druckleitung mit ihrem Druckleitungsteil 10a nicht in den Ringraum 34 mündet, sondern am zweiten Ventilsitz in den Ventilraum 24 einmündet. Der Druckleitungsteil 10b der Druckleitung zeigt dann vom Ringraum 34 ab. Die Steuerung des Steuerventils kann dabei in der gleichen Art und Weise erfolgen, wie beim ersten Ausführungsbeispiel. In der Ausgangsstellung liegt der Ventilkopf 23 mit seiner ersten Ventilkopfdichtflache 29 am ersten Ventilsitz 30 an, so daß der Ventilraum 24 dem von der Druckleitung 10a zugeführten hohen Druck ausgesetzt ist. Dieser Druck hält das Ventilschließglied 20 in Schließstellung. Soll eine Voreinspritzung erfolgen, so wird das Steuerventilglied 20 wie zuvor vom ersten Ventilsitz 30 weg, zum zweiten Ventilsitz 31 hinbewegt und es wird dabei die Verbindung zwischen den Druckleitungsteilen 10a und 10b kurzzeitig hergestellt, über eine Zeit, die ausreicht, eine Voreinspritzung V gemäß Figur 2a auszulösen. Bei Wiederanlage des Ventilkopfes 23 am zweiten Ventilsitz 31 ist dies Voreinspritzung dann beendet und nach einer Pause P wird das Steuerventilglied 20 wie zuvor in eine Zwischenstellung zwischen den beiden Ventilsitzen 30 und 31 gebracht zur Durchführung der Haupteinspritzung H. Anschließend wird diese Rückbewegung weitergeführt, bis der Ventilkopf 23 wieder am ersten Ventilsitz 30 anliegt und die Haupteinspritzung beendet .In Figure 3, the control valve is used in the essentially identical configuration as in Figure 1. The only difference here is that the pressure line with its pressure line part 10a does not open into the annular space 34, but opens into the valve space 24 at the second valve seat. The pressure line part 10b of the pressure line then points from the annular space 34. The control valve can be controlled in the same way as in the first exemplary embodiment. In the starting position, the valve head 23 rests with its first valve head sealing surface 29 on the first valve seat 30, so that the valve chamber 24 is exposed to the high pressure supplied by the pressure line 10a. This pressure keeps the valve closing member 20 in the closed position. If a pre-injection is to take place, the control valve member 20 is moved as before from the first valve seat 30 to the second valve seat 31 and the connection between the pressure line parts 10a and 10b is established briefly, over a time that is sufficient Trigger pre-injection V according to Figure 2a. When the valve head 23 is reinstalled on the second valve seat 31, this pre-injection is then ended and, after a pause P, the control valve member 20 is brought into an intermediate position between the two valve seats 30 and 31, as before, for carrying out the main injection H. Then this return movement is continued until the Valve head 23 rests against the first valve seat 30 and the main injection ends.
Bei dieser Ausgestaltung ist die Leckmenge entlang des Ventilstößels 21 reduziert, da dieser nur während der Einspritzphasen vom hohen Kraftstoffdruck beaufschlagt wird. Allerdings sind größere Betätigungskräfte des Steuerventilglieds erforderlich, was jedoch einfach durch einen Piezoaktor mit HydrauliküberSetzung erzielt werden kann. Die Hydraulikübersetzung ermöglicht dabei vorteilhaft die großen Öffnungshübe hvs . In this embodiment, the amount of leakage along the valve tappet 21 is reduced, since the high fuel pressure is only applied to it during the injection phases. However, larger actuation forces of the control valve member are required, but this can easily be achieved by a piezo actuator with hydraulic transmission. The hydraulic ratio advantageously enables the large opening strokes h vs.

Claims

Ansprüche Expectations
1. Kraftstoffeinspritzvorrichtung für Brennkraftmaschinen mit einer Kraftstoffhochdruckquelle (1) , aus der über eine Druckleitung (10a, 10b) ein Kraftstoffeinspritzventil (9) mit Kraftstoff versorgt wird, das zur Steuerung einer1. Fuel injection device for internal combustion engines with a high-pressure fuel source (1), from which a fuel injection valve (9) is supplied with fuel via a pressure line (10a, 10b), which is used to control a
Einspritzöffnung (17) ein Einspritzventilglied (12) aufweist mit einer einen Druckraum begrenzenden Druckschulter (14) , die vom Druck des über die Druckleitung (10a, 10b) zugeführten Kraftstoffs belastet ist, durch den das Einspritzventilglied (12) entgegen eine Rückstellkraft (15) zur Öffnung der Einspritzöffnung (17) von einem Einspritzventilsitz (13) abhebbar ist und mit einem die Bewegung des Einspritzventilgliedes (12) steuernden Steuerventil (18) , das ein von einem Piezoaktor (36) betätigtes Steuerventilglied (20) hat, mit einem in einem Gehäuse geführten Ventilstößel (21) , an dessen Ende ein in einen Ventilraum (24) ragender mit zwei einander gegenüberliegenden Ventilkopfdichtflachen (29, 32) versehener Ventilkopf (23) vorgesehen ist, der mit den Ventilkopfdichtflachen (29, 32) jeweils mit einem von zwei Ventilsitzen (30, 31) des Steuerventils zusammenwirkt und dabei den Durchtritt einer über den ersten Ventilsitz (30) dieser Ventilsitze in den Ventilraum (24) mündenden und den Ventilraum (24) über den zweiten Ventilsitz (31) dieser Ventilsitze verlassenden von der Kraftstoffhochdruckquelle herführenden Leitung (10a, 10b) steuert, wobei das Steuerventilglied (20) durch den Piezoaktor (36) so betätigbar ist, daß es mit seinem Ventilkopf (23) vom einem zum anderen der Ventilsitze bewegt wird oder in einer Zwischenstellung zwischen den beiden Ventilsitzen verharrt, in der beide Leitungsteile der von der Kraftstoffhochdruckquelle herführenden Leitung (10a, 10b) über den Ventilraum (24) miteinander verbunden sind, dadurch gekennzeichnet, daß das Steuerventil (20) zur Steuerung der Bewegung des Einspritzventilgliedes (12) in der zum von der Druckschulter (14) begrenzten Druckraum (11) führenden Druckleitung (10a, 10b) angeordnet ist.Injection opening (17) has an injection valve member (12) with a pressure shoulder (14) delimiting a pressure chamber, which is loaded by the pressure of the fuel supplied via the pressure line (10a, 10b), by means of which the injection valve member (12) counteracts a restoring force (15). for opening the injection opening (17) can be lifted off from an injection valve seat (13) and with a control valve (18) controlling the movement of the injection valve member (12) and having a control valve member (20) actuated by a piezo actuator (36), with one in one Housing-guided valve tappet (21), at the end of which a valve head (23), which projects into a valve chamber (24) and is provided with two valve head sealing faces (29, 32) lying opposite one another, is provided, which with the valve head sealing faces (29, 32) each has one of two Valve seats (30, 31) of the control valve cooperates and thereby the passage of one over the first valve seat (30) this valve seats opens into the valve chamber (24) and controls the valve chamber (24) via the second valve seat (31) of this valve seat and leads from the high-pressure fuel source (10a, 10b), the control valve member (20) being controlled by the piezo actuator (36) It can be actuated that it is moved with its valve head (23) from one to the other of the valve seats or remains in an intermediate position between the two valve seats, in which both line parts of the line (10a, 10b) leading from the high-pressure fuel source via the valve chamber (24) are interconnected, characterized in that the control valve (20) for controlling the movement of the injection valve member (12) is arranged in the pressure line (10a, 10b) leading to the pressure space (11) delimited by the pressure shoulder (14).
2. Kraftstoffeinspritzvorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß das Steuerventilglied (20) über eine hydraulische Übersetzung (37, 38, 39) vom Piezoaktor (36) betätigt wird.2. Fuel injection device according to claim 1, characterized in that the control valve member (20) via a hydraulic transmission (37, 38, 39) is actuated by the piezo actuator (36).
3. Kraftstoffeinspritzvorrichtung nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß der Ventilkopf (23) zwei konisch ausgebildete Ventilkopfdichtflachen (29, 32) aufweist, die mit kegelförmigen Ventilsitzen (30, 31) zusammenwirken und der Ventilstößel (21) anschließende an die Ventilkopfdichtflache (29) eine Ausnehmung (33) aufweist, die mit einer am ersten Ventilsitz endenden Ventilstößelbohrung (22) einen Ringraum (34) bildet, der mit der zur Kraftstoffhochdruckquelle (1) führenden Druckleitung (10a) ständig verbunden ist, welche Druckleitung (10b) vom zweiten Ventilsitz (31) aus weiter zum Druckraum (11) führt. 3. Fuel injection device according to claim 1 or 2, characterized in that the valve head (23) has two conical valve head sealing surfaces (29, 32) which cooperate with conical valve seats (30, 31) and the valve tappet (21) adjoining the valve head sealing surface ( 29) has a recess (33) which, with a valve tappet bore (22) ending at the first valve seat, forms an annular space (34) which is continuously connected to the pressure line (10a) leading to the high-pressure fuel source (1), which pressure line (10b) from second valve seat (31) leads further to the pressure chamber (11).
4. Kraftstoffeinspritzvorrichtung nach Anspruch 3, dadurch gekennzeichnet, daß in Richtung Ventilraum weisende größer ist als die entgegengesetzte zum Stößel weisende druckbeaufschlagte Fläche .4. Fuel injection device according to claim 3, characterized in that the direction pointing towards the valve chamber is larger than the opposite pressurized surface facing the tappet.
5. Kraftstoffeinspritzvorrichtung nach Anspruch 1 bis 3, dadurch gekennzeichnet, daß der Ventilkopf (23) zwei konisch ausgebildete Ventilkopfdichtflachen (29, 32) aufweist, die mit kegelförmigen Ventilsitzen (30, 31) zusammenwirken und der Ventilstößel (21) anschließende an die Ventilkopfdichtflache (29) eine Ausnehmung (33) aufweist, die mit einer am ersten Ventilsitz (30) endenden Ventilstößelbohrung (22) einen Ringraum (34) bildet, der mit der zum Druckraum (11) führenden Druckleitung (10b) ständig verbunden ist und die von Kraftstoffhochdruckquelle (1) herführende Druckleitung (10a) über den zweiten Ventilsitz (31) in den Ventilraum (24) mündet. 5. Fuel injection device according to claim 1 to 3, characterized in that the valve head (23) has two conical valve head sealing surfaces (29, 32) which cooperate with conical valve seats (30, 31) and the valve tappet (21) adjoining the valve head sealing surface ( 29) has a recess (33) which, with a valve tappet bore (22) ending at the first valve seat (30), forms an annular space (34) which is permanently connected to the pressure line (10b) leading to the pressure space (11) and which is from a high-pressure fuel source (1) leading pressure line (10a) opens into the valve chamber (24) via the second valve seat (31).
EP99964367A 1998-12-29 1999-11-24 Fuel injection device for internal combustion engines Expired - Lifetime EP1068445B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19860678 1998-12-29
DE19860678A DE19860678A1 (en) 1998-12-29 1998-12-29 Fuel injection device for internal combustion engines
PCT/DE1999/003721 WO2000039451A1 (en) 1998-12-29 1999-11-24 Fuel injection device for internal combustion engines

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EP1068445A1 true EP1068445A1 (en) 2001-01-17
EP1068445B1 EP1068445B1 (en) 2004-03-31

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US (1) US6422211B1 (en)
EP (1) EP1068445B1 (en)
JP (1) JP2002533613A (en)
DE (2) DE19860678A1 (en)
WO (1) WO2000039451A1 (en)

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DE19860678A1 (en) 2000-07-06
JP2002533613A (en) 2002-10-08
WO2000039451A1 (en) 2000-07-06
DE59909039D1 (en) 2004-05-06
US6422211B1 (en) 2002-07-23
EP1068445B1 (en) 2004-03-31

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