EP1584814B1 - Fuel injector controlled by a servo valve - Google Patents

Fuel injector controlled by a servo valve Download PDF

Info

Publication number
EP1584814B1
EP1584814B1 EP05100659A EP05100659A EP1584814B1 EP 1584814 B1 EP1584814 B1 EP 1584814B1 EP 05100659 A EP05100659 A EP 05100659A EP 05100659 A EP05100659 A EP 05100659A EP 1584814 B1 EP1584814 B1 EP 1584814B1
Authority
EP
European Patent Office
Prior art keywords
pressure
control
valve
piston
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.)
Expired - Fee Related
Application number
EP05100659A
Other languages
German (de)
French (fr)
Other versions
EP1584814A1 (en
Inventor
Hans-Christoph Magel
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 EP1584814A1 publication Critical patent/EP1584814A1/en
Application granted granted Critical
Publication of EP1584814B1 publication Critical patent/EP1584814B1/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

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
    • F02M57/00—Fuel-injectors combined or associated with other devices
    • F02M57/02—Injectors structurally combined with fuel-injection pumps
    • F02M57/022—Injectors structurally combined with fuel-injection pumps characterised by the pump drive
    • F02M57/025—Injectors structurally combined with fuel-injection pumps characterised by the pump drive hydraulic, e.g. with pressure amplification
    • 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
    • F02M47/025—Hydraulically 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
    • 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
    • F02M2547/00—Special features for fuel-injection valves actuated by fluid pressure
    • F02M2547/006—Springs assisting hydraulic closing force
    • 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
    • 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
    • F02M63/0028—Valves characterised by the valve actuating means hydraulic
    • F02M63/0029—Valves characterised by the valve actuating means hydraulic using a pilot valve controlling a hydraulic chamber
    • 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
    • F02M63/0049—Combined valve units, e.g. for controlling pumping chamber and injection valve

Definitions

  • the invention relates to a fuel injector for an internal combustion engine according to the preamble of claim 1.
  • a fuel injector for internal combustion engines with a pressure booster device for pressure boosting and with a servo valve for pressure-controlled control of the fuel injector is known.
  • the servo valve which is constructed as a 3/2-way control valve is controlled by a designed as a solenoid valve switching valve, whereby the pressure control of the fuel injector is realized.
  • the control valve has a longitudinally displaceable in a bore control piston with a control edge, which separates a high pressure system from a low pressure system. At the control piston of the control valve while various pressure chambers for connecting control lines are necessary, which are acted upon from the inside with the high pressure of the injection system.
  • the fuel injector according to the invention with the characterizing features of claim 1 has the advantage that the pressure piston portion and the control piston portion of the control piston, which are executed with different diameters, are guided in each case separate guide elements. For the different diameters of these sections of the control piston thus no double guide on a common guide element is necessary, whereby the manufacturing cost of the control valve is reduced. As a result, the technical controllability and reproducibility for series production is improved. At the same time acting in the control valve on the control piston and the components associated therewith compressive forces are compensated, whereby the deformation forces acting in the control valve are kept low. Consequently, no high notch stresses occur on the components, eg. B. in Bohrungsverschneidungen, so that the stresses occurring remain well below the fatigue strength values.
  • control cylinder surrounds the valve chamber and a cooperating with the control edge connecting channel formed in the pressure-balanced state with closed sealing seat of the control piston, a hydraulic connection between the pressure chamber and the valve chamber. It is also expedient if the control cylinder forms a further sealing seat in the pressure chamber which, in the pressure-relieved state, separates the pressure chamber from a valve chamber formed in the valve body. In this state, the connecting channel between the pressure chamber and valve chamber is closed at the same time.
  • the control piston is expediently designed so that it has a closing pressure surface in a control chamber and an operating pressure applied by the system pressure and the pressure chamber exposed pressure surface having.
  • the sealing seat of the control piston When the fuel injector is in the inactive state, the sealing seat of the control piston is closed and the slide seal provided with the control edge is opened on the control cylinder. In the active state of the fuel injector, the sealing seat of the control piston is opened and provided with the control edge slide seal on the control cylinder closed.
  • the movement speed of the control piston can be set arbitrarily.
  • a constantly defined opening force acts on the control piston. This results in an exact valve movement and a stable persistence of the control piston at the opening stop in the open state. Thereby, a slow opening movement of the control piston can be realized, so that a stable partial opening is possible, whereby the injection of a small amount can be ensured.
  • the control edge between the control piston portion of the control piston and the valve body can be executed in many ways.
  • the use of a flat seat for the sealing seats for sealing the pressure chamber with respect to the low-pressure or return system is particularly useful because it can compensate for any axial misalignment of the components occurring.
  • sufficient closing force is provided by the closing pressure force on the pressure surface of the control piston to ensure a sufficiently high surface pressure on the flat seat for a good tightness. It is also possible to have additional spring forces act on the control piston to support the valve movement of the control piston.
  • the control valve is particularly useful in conjunction with a pressure booster device which is connected between high-pressure source and injection valve, wherein the pressure booster device has a cooperating with a pressure booster piston rear chamber which can be controlled by the control valve, so that via a pressure change in the pressure chamber acting on the injection valve pressure intensification he follows.
  • FIG. 1 shows a schematic sectional view of a fuel injector according to the invention.
  • the fuel injector shown in the figure is connected via a fuel line 3 with a high-pressure fuel source 5.
  • the high-pressure fuel source 5 comprises several elements, not shown, such as fuel tank, high-pressure pump and a high pressure line, for example, a known common rail system, the pump provides, for example, up to 1600 bar high fuel pressure via the high pressure line.
  • the fuel injector further comprises a fuel injection valve 10, which projects with injection openings 11 into a combustion chamber of an internal combustion engine.
  • the fuel injection valve 10 has a valve pin designed as a closing piston 12 with a pressure shoulder 13 which is surrounded by a pressure chamber 14.
  • the closing piston 12 is guided at an end facing away from the combustion chamber in a guide region 15, to which a closing pressure chamber 16 connects.
  • the closing piston 12 is biased by a closing spring 17 in the closing direction.
  • the fuel injector also has pressure amplification via a pressure booster 20.
  • the pressure booster 20 has a by means of a return spring 18 resiliently mounted booster piston 21, which has a first partial piston 22 and a smaller diameter second partial piston 23.
  • the partial pistons 22, 23 are each assigned a corresponding, stepped diameter-shaped cylinder 24, so that the smaller-diameter partial piston 23 in the cylinder 24 separates a high pressure chamber 25 from a rear space 26 liquid-tight.
  • the larger diameter first partial piston 22, which is guided in the cylinder portion of the cylinder 24 with the larger diameter, also separates the back space 26 of a pressure transmission chamber 27 from liquid-tight.
  • the return spring 18 is arranged, which is biased to produce a corresponding return movement for the booster piston 21 between a spring holder 28 and a ring member 29.
  • the fuel injector has a servo valve, which comprises a hydraulic control valve 30 and an electrically controllable switching valve 50, the drive being effected by an electromagnetic or piezoelectric actuator 51.
  • the switching valve 50 has an actuator piston 52 connected to the actuator 51, which is guided in an actuator bore 53.
  • the actuator piston 52 separates an actuator-side low-pressure chamber 55 from an actuator-side control chamber 56 in a liquid-tight manner with an actuator-side sealing seat 54.
  • the control valve 30 has a valve body 31 with a receptacle 32.
  • a bush 33 is arranged, in which a control piston 34 is guided with a pressure piston portion 35.
  • the control piston 34 further includes a control piston portion 36 having a smaller diameter than the pressure piston portion 35.
  • the control piston section 36 has a guide region with a control edge 45 acting as a sealing edge.
  • the control piston portion 36 is guided with the guide portion in a piston guide 43 of a control cylinder 41, wherein the control cylinder 41 is also disposed in the receptacle 32 and is present as a separate from the sleeve 33 guide member for the control piston 34.
  • the control piston 34 has at the pressure piston portion 35 a pointing into a control chamber 37 pressure surface 38. Between the pressure piston portion 35 and the control piston portion 36, an annular surface is formed, which forms an opening pressure surface 39, as will be explained later.
  • the receptacle 32 forms a pressure chamber 40, in which the bushing 33 and the control cylinder 41 are acted upon from the outside with system pressure.
  • a sealing seat 46 which acts on the bottom surface of the pressure space 40 and separates a valve chamber 47 formed in the control cylinder 41 from a connection chamber 48 connected to a low pressure or return system.
  • the control cylinder 41 further has an end face with a sealing surface or sealing edge, which forms a further sealing seat 42 at the bottom of the receptacle 32, which separates the pressure chamber 40 from the valve chamber 47.
  • a compression spring 49 acts, which presses the sealing seat 42, in particular in the pressure-relieved state against the bottom surface of the pressure chamber 40.
  • connecting channel 44 is formed, which forms a hydraulic connection between the pressure chamber 40 and the valve chamber 47 in the closed state of the sealing seat 46.
  • pressure booster 20, control valve 30 and switching valve 40 serve pressure lines, which are integrated, for example, in the fuel injector.
  • the pressure chamber 14 of the injection valve 10 is connected to a first pressure line 61 to the high-pressure chamber 25 of the pressure booster 20.
  • a second pressure line 62 leads to the rear space 26 of the pressure booster 20.
  • connection line 63 with throttle between closing pressure chamber 16 and high-pressure chamber 25.
  • the hydraulic pressure of the high-pressure fuel source 5 is via the high-pressure line 3 in the pressure chamber 40 and from there via a pressure chamber line 64 into the pressure transmission chamber 27 of the pressure booster 20 guided.
  • the pressure transmission chamber 27 is thereby in communication with the pressure chamber 40 of the control valve 30.
  • a back-room line 65 connects the rear space 26 of the pressure booster 20 to the valve chamber 47 of the control valve 30.
  • a first return line 71 returns via the low-pressure or return system into a fuel tank (not shown).
  • the control chamber 33 of the control valve 30 is connected by means of a control line 66 via an outlet throttle 67 with the actuator-side control chamber 56 of the switching valve 50.
  • a second return line 72 leads out of the actuator-side low-pressure chamber 55 of the switching valve 50 into the low-pressure or return system.
  • the return lines 71, 72 may also be formed as a common return system.
  • a connecting bore 68 leads via an inlet throttle 69 from the control chamber 33 into the pressure chamber 40 of the control valve 30.
  • the operation of the fuel injector is as shown below: At the beginning of the injection process is due to the constant pressure in the high-pressure accumulator 5 the voltage applied in the pressure booster chamber 27 pressure on the back room line 65 in the back room 26 and via the second pressure line 62 and the connecting line 63 in the high-pressure chamber 25 and from there via the first pressure line 61 in the pressure chamber 14 of the injection valve 10.
  • the actuator 51 of the switching valve 50 which is a solenoid valve in the present embodiment, is energized so that the actuator piston 52 closes the control line 66, which is in communication with the control chamber 33 of the control valve 30, against the actuator-side low-pressure chamber 55 which is in communication with the second return line 72 ,
  • the voltage applied in the pressure chamber 40 System pressure or rail pressure transmitted via the connecting hole 68 in the control chamber 33.
  • the high pressure acting in the control chamber 33 acts on the pressure surface 38 and presses the control piston 41 with its sealing seat 46 against the bottom surface of the pressure chamber 40, so that the sealing seat 46 shuts off the communicating chamber 48 communicating with the return line 71.
  • control edge 45 is located outside the piston guide 43 of the valve body 41, so that a hydraulic connection via the connecting channel 44 between the pressure chamber 40 and the valve chamber 47 is made.
  • the first return line 71 is thus decoupled from the high pressure or system pressure and the injection valve 10 is closed.
  • the opening stroke of the closing piston 12 of the injection valve 10 is initiated by lifting the Aktorkolben 52 from the actuator-side sealing seat 54 due to a corresponding energization of the actuator 51, so that the control chamber 33 is connected to the actuator-side control chamber 56 and the Aktor facultyen low-pressure chamber 55.
  • the flow resistances of the inlet throttle 69 and the outlet throttle 67 are dimensioned such that the pressure in the control chamber 33 drops and the control piston 34 lifts off from the sealing seat 46 with the end face of the control piston section 36 and at the same time the control edge 45 on the piston guide 43 closes the connection channel 44.
  • valve chamber 47 is separated from the ruling in the pressure chamber 40 rail or system pressure and at the same time leading into the valve chamber 47 back-space line 65 is connected via the connecting chamber 48 to the return line 71 and thus to the low-pressure system. Accordingly, the pressure prevailing in the rear space 26 of the pressure booster 20 pressure on the return line 71 is released and the pressure in the rear chamber 26 drops.
  • the pressure booster device 20 is activated and the lower effective area afflicted second partial piston 23 compresses the fuel in the high pressure chamber 25, so that in the pressure chamber 14 connected to the high pressure chamber 25 in the opening direction of the pressure shoulder 13 acting pressure force increases and the closing piston 12 releases the injection ports , As long as the rear space 26 is depressurized, the pressure booster device 20 remains activated and compresses the fuel in the high-pressure space 25.
  • the switching valve 50 is returned to its initial position. This is due to the seating of the control piston 34 the sealing seat 46 of the rear chamber 26 of the pressure booster 20 is separated from the return line 71 and again pressurized via the valve chamber 47, the connecting channel 44 and the pressure chamber 40 with system pressure.
  • the system pressure is also passed via the return line 65 into the rear space 26, whereby the pressure booster piston 21 is returned by the return spring 18 in its initial position.
  • the pressure in the high-pressure chamber 25 drops to system pressure, as a result of which system pressure is likewise applied again in the pressure chamber 14, the high-pressure chamber 25 being filled via the connecting line 63 from the fuel source 5.
  • the provision of the closing piston 12 is realized by the system pressure also applied via the second pressure line 62, supported by the closing spring 17 arranged in the closing pressure chamber 16.

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)

Description

Die Erfindung betrifft einen Kraftstoffinjektor für eine Brennkraftmaschine nach dem Oberbegriff des Anspruchs 1.The invention relates to a fuel injector for an internal combustion engine according to the preamble of claim 1.

Stand der TechnikState of the art

Aus DE 102 18 904 A1 ist ein Kraftstoffinjektor für Brennkraftmaschinen mit einer Druckübersetzungseinrichtung zur Druckverstärkung und mit einem Servoventil zur druckgesteuerten Ansteuerung des Kraftstoffinjektors bekannt. Das Servoventil, das als 3/2-Steuerventil aufgebaut ist, wird von einem als Magnetventil ausgeführten Schaltventil angesteuert, wodurch die Drucksteuerung des Kraftstoffinjektors realisiert wird. Das Steuerventil weist dabei einen in einer Bohrung längsverschiebbaren Steuerkolben mit einer Steuerkante auf, die ein Hochdrucksystem von einem Niederdrucksystem trennt. Am Steuerkolben des Steuerventils sind dabei verschiedene Druckkammern zum Anschluss von Steuerleitungen notwendig, die dabei von innen mit dem Hochdruck des Einspritzsystems beaufschlagt sind. Diese Druckbeaufschlagung führt zur Aufweitung der Leckspalten an hochdruckdichten Führungen, zu Verformungen und Aufweitungen an den Steuerkanten der Schieberdichtungen sowie zu hohen Kerbspannungen in Bohrungsverschneidungen. Diese auf Grund der Druckbelastung auftretenden Einwirkungen verschlechtern die Funktion und somit die Dauerfestigkeit des Steuerventils.From DE 102 18 904 A1 a fuel injector for internal combustion engines with a pressure booster device for pressure boosting and with a servo valve for pressure-controlled control of the fuel injector is known. The servo valve, which is constructed as a 3/2-way control valve is controlled by a designed as a solenoid valve switching valve, whereby the pressure control of the fuel injector is realized. The control valve has a longitudinally displaceable in a bore control piston with a control edge, which separates a high pressure system from a low pressure system. At the control piston of the control valve while various pressure chambers for connecting control lines are necessary, which are acted upon from the inside with the high pressure of the injection system. This pressurization leads to the widening of the leakage gaps on high-pressure-tight guides, to deformations and widening on the control edges of the slide seals and to high notch stresses in bore intersections. These effects due to the pressure load worsen the function and thus the fatigue strength of the control valve.

In der DE-Patentanmeldung 103 37 574 A wurde bereits vorgeschlagen, den Steuerkolben in einer Buchse zu führen, die von außen mit Systemdruck beaufschlagt ist. Dadurch werden Aufweitungen der hochdruckdichten Führungen und der Steuerkanten, Verformungen des Ventils und hohe Kerbspannungen in Bohrungsverschneidungen erheblich verringert. Nachteilig ist jedoch, dass der Steuerkolben auf zwei unterschiedliche Durchmesser mit der Buchse eingeschliffen werden muss, was einen hohen Fertigungsaufwand erfordert.In DE patent application 103 37 574 A has already been proposed to guide the control piston in a socket which is acted upon from the outside with system pressure. As a result, expansions of the high-pressure-tight guides and the control edges, Deformations of the valve and high notch stresses in bore intersections significantly reduced. The disadvantage, however, is that the control piston must be ground to two different diameter with the socket, which requires a high production cost.

Vorteile der ErfindungAdvantages of the invention

Der erfindungsgemäße Kraftstoffinjektor mit den kennzeichnenden Merkmalen des Anspruchs 1 hat den Vorteil, dass der Druckkolbenabschnitt und der Steuerkolbenabschnitt des Steuerkolbens, die mit unterschiedlichen Durchmessern ausgeführten sind, in jeweils voneinander getrennten Führungselementen geführt sind. Für die unterschiedlichen Durchmesser dieser Abschnitte des Steuerkolbens ist somit keine Doppelführung an einem gemeinsamen Führungselement notwendig, wodurch der Fertigungsaufwand für das Steuerventil reduziert wird. Dadurch wird die fertigungstechnische Beherrschbarkeit und Reproduzierbarkeit für eine Serienfertigung verbessert. Gleichzeitig werden die im Steuerventil am Steuerkolben und an den damit in Verbindung stehenden Bauteilen wirkenden Druckkräfte kompensiert, wodurch die im Steuerventil wirkenden Verformungskräfte gering gehalten werden. Folglich treten keine hohen Kerbspannungen an den Bauteilen, z. B. in Bohrungsverschneidungen auf, so dass die auftretenden Spannungen deutlich unter den Dauerfestigkeitswerten bleiben.The fuel injector according to the invention with the characterizing features of claim 1 has the advantage that the pressure piston portion and the control piston portion of the control piston, which are executed with different diameters, are guided in each case separate guide elements. For the different diameters of these sections of the control piston thus no double guide on a common guide element is necessary, whereby the manufacturing cost of the control valve is reduced. As a result, the technical controllability and reproducibility for series production is improved. At the same time acting in the control valve on the control piston and the components associated therewith compressive forces are compensated, whereby the deformation forces acting in the control valve are kept low. Consequently, no high notch stresses occur on the components, eg. B. in Bohrungsverschneidungen, so that the stresses occurring remain well below the fatigue strength values.

Durch die in den Unteransprüchen aufgeführten Maßnahmen sind vorteilhafte Weiterbildungen und Verbesserungen des im Hauptanspruch angegebenen Kraftstoffinjektors möglich.The measures listed in the dependent claims advantageous refinements and improvements of the main claim fuel injector are possible.

Besonders zweckmäßig ist es, wenn der Steuerzylinder die Ventilkammer umgibt und ein mit der Steuerkante zusammenwirkender Verbindungskanal im druckausgeglichenen Zustand bei geschlossenem Dichtsitz des Steuerkolbens eine hydraulische Verbindung zwischen Druckraum und Ventilkammer ausgebildet. Zweckmäßig ist ferner, wenn der Steuerzylinder einen weiterer Dichtsitz im Druckraum ausgebildet, der im druckentlasteten Zustand den Druckraum von einer im Ventilkörper ausgebildeten Ventilkammer trennt. In diesem Zustand ist gleichzeitig der Verbindungskanal Zwischen Druckraum und Ventilkammer geschlossen. Der Steuerkolben ist zweckmäßiger Weise so ausgebildet, dass er eine schließende Druckfläche im einem Steuerraum und eine vom Systemdruck beaufschlagt und den Druckraum ausgesetzte öffnende Druckfläche aufweist. Im inaktiven Zustand des Kraftstoffinjektors ist der Dichtsitz des Steuerkolbens geschlossen und die mit der Steuerkante versehene Schieberdichtung am Steuerzylinder geöffnet. Im aktiven Zustand des Kraftstoffinjektors ist der Dichtsitz des Steuerkolbens geöffnet und die mit der Steuerkante versehene Schieberdichtung am Steuerzylinder geschlossen.It is particularly useful when the control cylinder surrounds the valve chamber and a cooperating with the control edge connecting channel formed in the pressure-balanced state with closed sealing seat of the control piston, a hydraulic connection between the pressure chamber and the valve chamber. It is also expedient if the control cylinder forms a further sealing seat in the pressure chamber which, in the pressure-relieved state, separates the pressure chamber from a valve chamber formed in the valve body. In this state, the connecting channel between the pressure chamber and valve chamber is closed at the same time. The control piston is expediently designed so that it has a closing pressure surface in a control chamber and an operating pressure applied by the system pressure and the pressure chamber exposed pressure surface having. When the fuel injector is in the inactive state, the sealing seat of the control piston is closed and the slide seal provided with the control edge is opened on the control cylinder. In the active state of the fuel injector, the sealing seat of the control piston is opened and provided with the control edge slide seal on the control cylinder closed.

Durch eine geeignete Abstimmung einer ersten Drossel, über die eine Verbindung vom Steuerraum zu einem aktorseitigen Steuerraum erfolgt, und einer zweiten Drossel, über die eine Verbindung zwischen dem Steuerraum und dem Hochdruckraum realisiert wird, kann die Bewegungsgeschwindigkeit des Steuerkolbens beliebig eingestellt werden. Infolge des an der öffnenden Druckfläche ständig anliegenden Systemdrucks, wirkt dort eine ständig definierte öffnende Kraft auf den Steuerkolben ein. Damit ergibt sich eine exakte Ventilbewegung und ein stabiles Verharren des Steuerkolbens am Öffnungsanschlag im geöffneten Zustand. Dadurch kann eine langsame Öffnungsbewegung des Steuerkolbens realisiert werden, so dass eine stabile Teilöffnung möglich ist, wodurch die Einspritzung einer Kleinstmenge sicher gestellt werden kann.By a suitable tuning of a first throttle, via which a connection from the control chamber to an actuator-side control chamber, and a second throttle, via which a connection between the control chamber and the high-pressure chamber is realized, the movement speed of the control piston can be set arbitrarily. As a result of the system pressure constantly applied to the opening pressure surface, a constantly defined opening force acts on the control piston. This results in an exact valve movement and a stable persistence of the control piston at the opening stop in the open state. Thereby, a slow opening movement of the control piston can be realized, so that a stable partial opening is possible, whereby the injection of a small amount can be ensured.

Die Steuerkante zwischen dem Steuerkolbenabschnitt des Steuerkolbens und dem Ventilkörper ist in vielfältiger Weise ausführbar. Die Verwendung eines Flachsitzes für die Dichtsitze zur Abdichtung des Druckraums gegenüber dem Niederdruck- bzw. Rücklaufsystem ist besonders zweckmäßig, weil dadurch ein eventuell auftretender Achsversatz der Bauteile ausgeglichen werden kann. Außerdem ist durch die schließende Druckkraft über die Druckfläche des Steuerkolbens genügend Schließkraft vorhanden, um am Flachsitz eine genügend hohe Flächenpressung für eine gute Dichtheit zu garantieren. Außerdem ist es möglich, zur Unterstützung der Ventilbewegung des Steuerkolbens zusätzliche Federkräfte auf den Steuerkolben wirken zu lassen.The control edge between the control piston portion of the control piston and the valve body can be executed in many ways. The use of a flat seat for the sealing seats for sealing the pressure chamber with respect to the low-pressure or return system is particularly useful because it can compensate for any axial misalignment of the components occurring. In addition, sufficient closing force is provided by the closing pressure force on the pressure surface of the control piston to ensure a sufficiently high surface pressure on the flat seat for a good tightness. It is also possible to have additional spring forces act on the control piston to support the valve movement of the control piston.

Das Steuerventil ist besonders zweckmäßig einsetzbar in Verbindung mit einer Druckübersetzungseinrichtung, die zwischen Hochdruckquelle und Einspritzventil geschaltet ist, wobei die Druckübersetzungseinrichtung einen mit einem Druckübersetzerkolben zusammenwirkenden Rückraum besitzt, der vom Steuerventil ansteuerbar ist, so dass über eine Druckänderung im Druckraum eine auf das Einspritzventil einwirkende Druckübersetzung erfolgt.The control valve is particularly useful in conjunction with a pressure booster device which is connected between high-pressure source and injection valve, wherein the pressure booster device has a cooperating with a pressure booster piston rear chamber which can be controlled by the control valve, so that via a pressure change in the pressure chamber acting on the injection valve pressure intensification he follows.

Zeichnungdrawing

Ein Ausführungsbeispiel der Erfindung ist in der Zeichnung dargestellt und in der nachfolgenden Beschreibung näher erläutert. Die Figur zeigt eine schematische Schnittdarstellung eines erfindungsgemäßen Kraftstoffinjektors.An embodiment of the invention is illustrated in the drawing and explained in more detail in the following description. The figure shows a schematic sectional view of a fuel injector according to the invention.

Ausführungsbeispielembodiment

Der in der Figur dargestellte Kraftstoffinjektor ist über eine Kraftstoffleitung 3 mit einer Kraftstoffhochdruckquelle 5 verbunden. Die Kraftstoffhochdruckquelle 5 umfasst dabei mehrere nicht dargestellte Elemente, wie Kraftstofftank, Hochdruckpumpe und eine Hochdruckleitung, beispielsweise eines an sich bekannten Common-Rail-Systems, wobei die Pumpe beispielsweise einen bis zu 1600 bar hohen Kraftstoffdruck über die Hochdruckleitung bereitstellt. Der Kraftstoffinjektor weist ferner ein Kraftstoffeinspritzventil 10 auf, das mit Einspritzöffnungen 11 in einen Brennraum einer Brennkraftmaschine hineinragt.The fuel injector shown in the figure is connected via a fuel line 3 with a high-pressure fuel source 5. The high-pressure fuel source 5 comprises several elements, not shown, such as fuel tank, high-pressure pump and a high pressure line, for example, a known common rail system, the pump provides, for example, up to 1600 bar high fuel pressure via the high pressure line. The fuel injector further comprises a fuel injection valve 10, which projects with injection openings 11 into a combustion chamber of an internal combustion engine.

Das Kraftstoffeinspritzventil 10 besitzt einen als Ventilnadel ausgebildeten Schließkolben 12 mit einer Druckschulter 13, die von einem Druckraum 14 umgeben ist. Der Schließkolben 12 ist an einen dem Brennraum abgewandten Ende in einem Führungsbereich 15 geführt, an den sich ein Schließdruckraum 16 anschließt. Der Schließkolben 12 ist mittels einer Schließfeder 17 in Schließrichtung vorgespannt.The fuel injection valve 10 has a valve pin designed as a closing piston 12 with a pressure shoulder 13 which is surrounded by a pressure chamber 14. The closing piston 12 is guided at an end facing away from the combustion chamber in a guide region 15, to which a closing pressure chamber 16 connects. The closing piston 12 is biased by a closing spring 17 in the closing direction.

Der Kraftstoffinjektor verfügt ferner zur Druckverstärkung über eine Druckübersetzungseinrichtung 20. Die Druckübersetzungseinrichtung 20 besitzt einen mittels einer Rückstellfeder 18 federnd gelagerten Übersetzerkolben 21, der einen ersten Teilkolben 22 und einen im Durchmesser kleineren zweiten Teilkolben 23 aufweist. Den Teilkolben 22, 23 ist jeweils ein entsprechender, im Durchmesser gestuft ausgebildeter Zylinder 24 zugeordnet, so dass der im Durchmesser kleinere Teilkolben 23 im Zylinder 24 einen Hochdruckraum 25 von einem Rückraum 26 flüssigkeitsdicht abtrennt. Der im Durchmesser größere erste Teilkolben 22, der in dem Zylinderabschnitt des Zylinders 24 mit dem größeren Durchmesser geführt ist, trennt außerdem den Rückraum 26 von einem Druckübersetzungsraum 27 flüssigkeitsdicht ab. Im Druckübersetzungsraum 27 ist die Rückstellfeder 18 angeordnet, die zur Erzeugung einer entsprechenden Rückstellbewegung für den Übersetzerkolben 21 zwischen einem Federhalter 28 und einem Ringelement 29 vorgespannt ist.The fuel injector also has pressure amplification via a pressure booster 20. The pressure booster 20 has a by means of a return spring 18 resiliently mounted booster piston 21, which has a first partial piston 22 and a smaller diameter second partial piston 23. The partial pistons 22, 23 are each assigned a corresponding, stepped diameter-shaped cylinder 24, so that the smaller-diameter partial piston 23 in the cylinder 24 separates a high pressure chamber 25 from a rear space 26 liquid-tight. The larger diameter first partial piston 22, which is guided in the cylinder portion of the cylinder 24 with the larger diameter, also separates the back space 26 of a pressure transmission chamber 27 from liquid-tight. In the pressure booster chamber 27, the return spring 18 is arranged, which is biased to produce a corresponding return movement for the booster piston 21 between a spring holder 28 and a ring member 29.

Weiterhin verfügt der Kraftstoffnjektor über ein Servoventil, das ein hydraulisches Steuerventil 30 und ein elektrisch ansteuerbares Schaltventil 50 umfasst, wobei die Ansteuerung von einem elektromagnetischen oder piezoelektrischen Aktor 51 erfolgt. Das Schaltventil 50 weist einen mit dem Aktor 51 verbundenen Aktorkolben 52 auf, der in einer Aktorbohrung 53 geführt ist. Der Aktorkolben 52 trennt mit einem aktorseitigen Dichtsitz 54 einen aktorseitigen Niederdruckraum 55 von einem aktorseitigen Steuerraum 56 flüssigkeitsdicht ab.Furthermore, the fuel injector has a servo valve, which comprises a hydraulic control valve 30 and an electrically controllable switching valve 50, the drive being effected by an electromagnetic or piezoelectric actuator 51. The switching valve 50 has an actuator piston 52 connected to the actuator 51, which is guided in an actuator bore 53. The actuator piston 52 separates an actuator-side low-pressure chamber 55 from an actuator-side control chamber 56 in a liquid-tight manner with an actuator-side sealing seat 54.

Das Steuerventil 30 weist einen Ventilkörper 31 mit einer Aufnahme 32 auf. In der Aufnahme 32 ist eine Buchse 33 angeordnet, in der ein Steuerkolben 34 mit einem Druckkolbenabschnitt 35 geführt ist. Der Steuerkolben 34 umfasst weiterhin einen Steuerkolbenabschnitt 36, der einen kleineren Durchmesser als der Druckkolbenabschnitt 35 besitzt. Der Steuerkolbenabschnitt 36 weist einen Führungsbereich mit einer als Dichtkante wirkenden Steuerkante 45 auf. Der Steuerkolbenabschnitt 36 ist mit dem Führungsbereich in einer Kolbenführung 43 eines Steuerzylinders 41 geführt, wobei der Steuerzylinder 41 ebenfalls in der Aufnahme 32 angeordnet und als ein von der Buchse 33 getrenntes Führungselement für den Steuerkolben 34 vorliegt. Der Steuerkolben 34 besitzt am Druckkolbenabschnitt 35 eine in einen Steuerraum 37 weisende Druckfläche 38. Zwischen Druckkolbenabschnitt 35 und Steuerkolbenabschnitt 36 ist eine Ringfläche ausgebildet, die eine öffnende Druckfläche 39, wie später noch erläutert wird, bildet.The control valve 30 has a valve body 31 with a receptacle 32. In the receptacle 32, a bush 33 is arranged, in which a control piston 34 is guided with a pressure piston portion 35. The control piston 34 further includes a control piston portion 36 having a smaller diameter than the pressure piston portion 35. The control piston section 36 has a guide region with a control edge 45 acting as a sealing edge. The control piston portion 36 is guided with the guide portion in a piston guide 43 of a control cylinder 41, wherein the control cylinder 41 is also disposed in the receptacle 32 and is present as a separate from the sleeve 33 guide member for the control piston 34. The control piston 34 has at the pressure piston portion 35 a pointing into a control chamber 37 pressure surface 38. Between the pressure piston portion 35 and the control piston portion 36, an annular surface is formed, which forms an opening pressure surface 39, as will be explained later.

Die Aufnahme 32 bildet einen Druckraum 40, in dem die Buchse 33 und der Steuerzylinder 41 von außen mit Systemdruck beaufschlagt sind. An der Stirnfläche des Steuerkolbenabschnitts 36 ist ein Dichtsitz 46 vorhanden, der auf die Bodenfläche des Druckraums 40 einwirkt und eine im Steuerzylinder 41 ausgebildete Ventilkammer 47 von einer mit einem Niederdruck- bzw. Rücklaufsystem verbundene Verbindungskammer 48 trennt. Der Steuerzylinder 41 weist ferner eine Stirnfläche mit einer Dichtfläche bzw. Dichtkante auf, die am Boden der Aufnahme 32 einen weiteren Dichtsitz 42 ausbildet, der den Druckraum 40 von der Ventilkammer 47 trennt. Auf den Steuerzylinder 41 wirkt eine Druckfeder 49 ein, die den Dichtsitz 42, insbesondere im druckentlasteten Zustand gegen die Bodenfläche des Druckraums 40 drückt. Am Führungsbereich des Steuerkolbenabschnitts 36 ist ein mit der Steuerkante 45 zusammenwirkender Verbindungskanal 44 ausgebildet, der im geschlossenen Zustand des Dichtsitzes 46 eine hydraulische Verbindung zwischen Druckraum 40 und Ventilkammer 47 bildet.The receptacle 32 forms a pressure chamber 40, in which the bushing 33 and the control cylinder 41 are acted upon from the outside with system pressure. On the end face of the control piston portion 36 there is a sealing seat 46 which acts on the bottom surface of the pressure space 40 and separates a valve chamber 47 formed in the control cylinder 41 from a connection chamber 48 connected to a low pressure or return system. The control cylinder 41 further has an end face with a sealing surface or sealing edge, which forms a further sealing seat 42 at the bottom of the receptacle 32, which separates the pressure chamber 40 from the valve chamber 47. On the control cylinder 41, a compression spring 49 acts, which presses the sealing seat 42, in particular in the pressure-relieved state against the bottom surface of the pressure chamber 40. At the guide portion of the control piston portion 36 cooperating with the control edge 45 connecting channel 44 is formed, which forms a hydraulic connection between the pressure chamber 40 and the valve chamber 47 in the closed state of the sealing seat 46.

Zur Verbindung der einzelnen Komponenten Einspritzventil 10, Druckübersetzungseinrichtung 20, Steuerventil 30 und Schaltventil 40, dienen Druckleitungen, die beispielsweise in den Kraftstoffinjektor integriert sind. Der Druckraum 14 des Einspritzventils 10 ist mit einer ersten Druckleitung 61 mit dem Hochdruckraum 25 der Druckübersetzungseinrichtung 20 verbunden. Vom Schließdruckraum 16 des Einspritzventils 10 führt eine zweite Druckleitung 62 zum Rückraum 26 der Druckübersetzungseinrichtung 20. Zusätzlich existiert eine Verbindungsleitung 63 mit Drossel zwischen Schließdruckraum 16 und Hochdruckraum 25. Der hydraulische Druck der Kraftstoffhochdruckquelle 5 wird über die Hochdruckleitung 3 in den Druckraum 40 und von dort über eine Druckraumleitung 64 in den Druckübersetzungsraum 27 der Druckübersetzungseinrichtung 20 geführt. Der Druckübersetzungsraum 27 steht dadurch mit dem Druckraum 40 des Steuerventils 30 in Verbindung. Eine Rückraumleitung 65 verbindet den Rückraum 26 der Druckübersetzungseinrichtung 20 mit der Ventilkammer 47 des Steuerventils 30. Von der Verbindungskammer 48 führt eine erste Rücklaufleitung 71 über das Niederdruck- bzw. Rücklaufsystem in einen nicht dargestellten Kraftstofftank zurück. Der Steuerraum 33 des Steuerventils 30 ist mittels einer Steuerleitung 66 über eine Ablaufdrossel 67 mit dem aktorseitigen Steuerraum 56 des Schaltventils 50 verbunden. Eine zweite Rücklaufleitung 72 führt aus dem aktorseitigen Niederdruckraum 55 des Schaltventils 50 heraus in das Niederdruck- bzw. Rücklaufsystem hinein. Die Rücklaufleitungen 71, 72 können auch als ein gemeinsames Rücklaufsystem ausgebildet sein. Schließlich führt eine Verbindungsbohrung 68 über eine Zulaufdrossel 69 vom Steuerraum 33 in den Druckraum 40 des Steuerventils 30.To connect the individual components injection valve 10, pressure booster 20, control valve 30 and switching valve 40, serve pressure lines, which are integrated, for example, in the fuel injector. The pressure chamber 14 of the injection valve 10 is connected to a first pressure line 61 to the high-pressure chamber 25 of the pressure booster 20. From the closing pressure chamber 16 of the injection valve 10, a second pressure line 62 leads to the rear space 26 of the pressure booster 20. In addition, there is a connection line 63 with throttle between closing pressure chamber 16 and high-pressure chamber 25. The hydraulic pressure of the high-pressure fuel source 5 is via the high-pressure line 3 in the pressure chamber 40 and from there via a pressure chamber line 64 into the pressure transmission chamber 27 of the pressure booster 20 guided. The pressure transmission chamber 27 is thereby in communication with the pressure chamber 40 of the control valve 30. A back-room line 65 connects the rear space 26 of the pressure booster 20 to the valve chamber 47 of the control valve 30. From the connecting chamber 48, a first return line 71 returns via the low-pressure or return system into a fuel tank (not shown). The control chamber 33 of the control valve 30 is connected by means of a control line 66 via an outlet throttle 67 with the actuator-side control chamber 56 of the switching valve 50. A second return line 72 leads out of the actuator-side low-pressure chamber 55 of the switching valve 50 into the low-pressure or return system. The return lines 71, 72 may also be formed as a common return system. Finally, a connecting bore 68 leads via an inlet throttle 69 from the control chamber 33 into the pressure chamber 40 of the control valve 30.

Die Funktionsweise des Kraftstoffinjektors ist wie im Folgenden dargestellt: Zu Beginn des Einspritzvorgangs liegt durch den konstanten Druck im Hochdruckspeicher 5 der im Druckübersetzungsraum 27 anliegende Druck über die Rückraumleitung 65 auch im Rückraum 26 und über die zweite Druckleitung 62 und die Verbindungsleitung 63 im Hochdruckraum 25 und von dort über die erste Druckleitung 61 im Druckraum 14 des Einspritzventils 10 an. Der Aktor 51 des Schaltventils 50, das im vorliegenden Ausführungsbeispiel ein Magnetventil ist, ist so bestromt, dass der Aktorkolben 52 die mit dem Steuerraum 33 des Steuerventils 30 in Verbindung stehende Steuerleitung 66 gegen den mit der zweiten Rücklaufleitung 72 in Verbindung stehenden aktorseitigen Niederdruckraum 55 verschließt. Dadurch wird der im Druckraum 40 anliegende Systemdruck bzw. Raildruck über die Verbindungsbohrung 68 in den Steuerraum 33 übertragen. Der im Steuerraum 33 wirkende Hochdruck wirkt auf die Druckfläche 38 ein und drückt den Steuerkolben 41 mit seinem Dichtsitz 46 gegen die Bodenfläche des Druckraums 40, so dass der Dichtsitz 46 die mit der Rücklaufleitung 71 in Verbindung stehende Verbindungskammer 48 absperrt. In dieser Position des Steuerkolbens 41 befindet sich die Steuerkante 45 außerhalb der Kolbenführung 43 des Ventilkörpers 41, so dass eine hydraulische Verbindung über den Verbindungskanal 44 zwischen dem Druckraum 40 und der Ventilkammer 47 hergestellt ist. Die erste Rücklaufleitung 71 ist somit vom Hochdruck bzw. Systemdruck entkoppelt und das Einspritzventil 10 ist geschlossen.The operation of the fuel injector is as shown below: At the beginning of the injection process is due to the constant pressure in the high-pressure accumulator 5 the voltage applied in the pressure booster chamber 27 pressure on the back room line 65 in the back room 26 and via the second pressure line 62 and the connecting line 63 in the high-pressure chamber 25 and from there via the first pressure line 61 in the pressure chamber 14 of the injection valve 10. The actuator 51 of the switching valve 50, which is a solenoid valve in the present embodiment, is energized so that the actuator piston 52 closes the control line 66, which is in communication with the control chamber 33 of the control valve 30, against the actuator-side low-pressure chamber 55 which is in communication with the second return line 72 , As a result, the voltage applied in the pressure chamber 40 System pressure or rail pressure transmitted via the connecting hole 68 in the control chamber 33. The high pressure acting in the control chamber 33 acts on the pressure surface 38 and presses the control piston 41 with its sealing seat 46 against the bottom surface of the pressure chamber 40, so that the sealing seat 46 shuts off the communicating chamber 48 communicating with the return line 71. In this position of the control piston 41, the control edge 45 is located outside the piston guide 43 of the valve body 41, so that a hydraulic connection via the connecting channel 44 between the pressure chamber 40 and the valve chamber 47 is made. The first return line 71 is thus decoupled from the high pressure or system pressure and the injection valve 10 is closed.

Die Öffnungshubbewegung des Schließkolbens 12 des Einspritzventils 10 wird dadurch eingeleitet, indem auf Grund einer entsprechenden Bestromung des Aktors 51 der Aktorkolben 52 vom aktorseitigen Dichtsitz 54 abhebt, so dass der Steuerraum 33 mit dem aktorseitigen Steuerraum 56 und dem aktorseitigen Niederdruckraum 55 verbunden wird. Die Durchflusswiderstände der Zulaufdrossel 69 und der Ablaufdrossel 67 sind so bemessen, dass der Druck im Steuerraum 33 abfällt und der Steuerkolben 34 mit der Stirnfläche des Steuerkolbenabschnitts 36 vom Dichtsitz 46 abhebt und gleichzeitig die Steuerkante 45 an der Kolbenführung 43 den Verbindungskanal 44 verschließt. Dadurch ist die Ventilkammer 47 von dem in der Druckkammer 40 herrschenden Rail- bzw. Systemdruck getrennt und gleichzeitig ist die in die Ventilkammer 47 führende Rückraumleitung 65 über die Verbindungskammer 48 an die Rücklaufleitung 71 und damit an das Niederdrucksystem angeschlossen. Dementsprechend wird der im Rückraum 26 der Druckübersetzungseinrichtung 20 herrschende Druck über die Rücklaufleitung 71 entspannt und der Druck im Rückraum 26 fällt ab. Dadurch wird die Druckübersetzungseinrichtung 20 aktiviert und der mit geringerer Wirkfläche behaftete zweite Teilkolben 23 verdichtet den Kraftstoff im Hochdruckraum 25, so dass in dem mit dem Hochdruckraum 25 verbundenen Druckraum 14 die in Öffnungsrichtung an der Druckschulter 13 angreifende Druckkraft ansteigt und der Schließkolben 12 die Einspritzöffnungen freigibt. So lange der Rückraum 26 druckentlastet ist, bleibt die Druckübersetzungseinrichtung 20 aktiviert und verdichtet den Kraftstoff im Hochdruckraum 25.The opening stroke of the closing piston 12 of the injection valve 10 is initiated by lifting the Aktorkolben 52 from the actuator-side sealing seat 54 due to a corresponding energization of the actuator 51, so that the control chamber 33 is connected to the actuator-side control chamber 56 and the Aktorseitigen low-pressure chamber 55. The flow resistances of the inlet throttle 69 and the outlet throttle 67 are dimensioned such that the pressure in the control chamber 33 drops and the control piston 34 lifts off from the sealing seat 46 with the end face of the control piston section 36 and at the same time the control edge 45 on the piston guide 43 closes the connection channel 44. As a result, the valve chamber 47 is separated from the ruling in the pressure chamber 40 rail or system pressure and at the same time leading into the valve chamber 47 back-space line 65 is connected via the connecting chamber 48 to the return line 71 and thus to the low-pressure system. Accordingly, the pressure prevailing in the rear space 26 of the pressure booster 20 pressure on the return line 71 is released and the pressure in the rear chamber 26 drops. As a result, the pressure booster device 20 is activated and the lower effective area afflicted second partial piston 23 compresses the fuel in the high pressure chamber 25, so that in the pressure chamber 14 connected to the high pressure chamber 25 in the opening direction of the pressure shoulder 13 acting pressure force increases and the closing piston 12 releases the injection ports , As long as the rear space 26 is depressurized, the pressure booster device 20 remains activated and compresses the fuel in the high-pressure space 25.

Zum Beenden des Einspritzvorganges wird das Schaltventil 50 wieder in seine Ausgangsstellung überführt. Dadurch wird durch das Aufsitzen des Steuerkolbens 34 auf dem Dichtsitz 46 der Rückraum 26 der Druckübersetzungseinrichtung 20 von der Rücklaufleitung 71 getrennt und wieder über die Ventilkammer 47, den Verbindungskanal 44 und den Druckraum 40 mit Systemdruck beaufschlagt. Der Systemdruck wird über die Rücklaufleitung 65 ebenfalls in den Rückraum 26 geleitet, wodurch der Druckübersetzungskolben 21 unterstützt durch die Rückstellfeder 18 in seine Ausgangsstellung zurückgeführt wird. Dadurch fällt der Druck im Hochdruckraum 25 auf Systemdruck ab, wodurch im Druckraum 14 ebenfalls wieder Systemdruck anliegt, wobei der Hochdruckraum 25 über die Verbindungsleitung 63 aus der Kraftstoffquelle 5 befüllt wird. Die Rückstellung des Schließkolbens 12 wird dabei durch den ebenfalls über die zweite Druckleitung 62 anliegenden Systemdruck, unterstützt durch die im Schließdruckraum 16 angeordnete Schließfeder 17 realisiert.To end the injection process, the switching valve 50 is returned to its initial position. This is due to the seating of the control piston 34 the sealing seat 46 of the rear chamber 26 of the pressure booster 20 is separated from the return line 71 and again pressurized via the valve chamber 47, the connecting channel 44 and the pressure chamber 40 with system pressure. The system pressure is also passed via the return line 65 into the rear space 26, whereby the pressure booster piston 21 is returned by the return spring 18 in its initial position. As a result, the pressure in the high-pressure chamber 25 drops to system pressure, as a result of which system pressure is likewise applied again in the pressure chamber 14, the high-pressure chamber 25 being filled via the connecting line 63 from the fuel source 5. The provision of the closing piston 12 is realized by the system pressure also applied via the second pressure line 62, supported by the closing spring 17 arranged in the closing pressure chamber 16.

BezugszeichenlisteLIST OF REFERENCE NUMBERS

33
KraftstoffleitungFuel line
55
KraftstoffhochdruckquelleHigh-pressure fuel source
1010
KraftstoffeinspritzventilFuel injection valve
1111
EinspritzöffnungInjection port
1212
Schließkolbenclosing piston
1313
Druckschulterpressure shoulder
1414
Druckraumpressure chamber
1515
Führungsbereichguide region
1616
SchließdruckraumClosing pressure chamber
1717
Schließfederclosing spring
1818
RückstellfederReturn spring
2020
DruckübersetzungseinrichtungPressure booster device
2121
ÜbersetzerkolbenBooster piston
2222
erster Teilkolbenfirst part piston
2323
zweiter Teilkolbensecond partial piston
2424
Zylindercylinder
2525
HochdruckraumHigh-pressure chamber
2626
Rückraumbackcourt
2727
DruckübersetzungsraumPressure boosting chamber
2828
Federhalterpenholder
2929
Ringelementring element
3030
Steuerventilcontrol valve
3131
Ventilkörpervalve body
3232
Aufnahmeadmission
3333
BuchseRifle
3434
Steuerkolbenspool
3535
DruckkolbenabschnittPressure piston section
3636
SteuerkolbenabschnittSpool section
3737
Steuerraumcontrol room
3838
Druckflächeprint area
3939
Öffnende DruckflächeOpening pressure surface
4040
Druckraumpressure chamber
4141
Steuerzylindercontrol cylinder
4242
Dichtsitzsealing seat
4343
Zylinderführungcylinder guide
4444
Verbindungskanalconnecting channel
4545
Steuerkantecontrol edge
4646
Dichtsitzsealing seat
4747
Ventilkammervalve chamber
4848
Verbindungskammerconnecting chamber
4949
Druckfedercompression spring
5050
Schaltventilswitching valve
5151
Aktoractuator
5252
Aktorkolbenactuator piston
5353
Aktorbohrungactuator bore
5454
aktorseitiger DichtsitzActuator-side sealing seat
5555
aktorseitiger Niederdruckraumactuator-side low pressure space
5656
aktorseitiger SteuerraumActuator-side control room
6161
erste Druckleitungfirst pressure line
6262
zweite Druckleitungsecond pressure line
6363
Verbindungsleitungconnecting line
6464
DruckraumleitungPressure chamber line
6565
RückraumleitungBackcourt line
6666
Steuerleitungcontrol line
6767
Zulaufdrosselinlet throttle
6868
Verbindungsbohrungconnecting bore
6969
Zulaufdrosselinlet throttle
7171
erste Rücklaufleitungfirst return line
7272
zweite Rücklaufleitungsecond return line

Claims (10)

  1. Fuel injector for an internal combustion engine having a fuel injection valve (10), which is connected to a high pressure source, and having a control valve (30) which, in a valve body (31), comprises a control piston (34) which is arranged so as to be longitudinally displaceable and has one pressure piston section (35), which is guided in a sleeve (33), with a first pressure face (38), and one control piston section (36) with a sliding seal which has a control edge (45), the sleeve (33) being arranged in a pressure space (40) of the valve body (41) and being at least partially externally acted on with system pressure, the control piston (34) in a first valve position separating a valve chamber (47) from a low pressure or return system by means of a sealing seat (46) which is acted on by the pressure face (38), and the control piston (34) in a second valve position separating the pressure space (40) from the valve chamber (47) by means of the control edge (45) and, at the same time, producing a connection from the valve chamber (47) to the low pressure or return system by means of the sealing seat (46) and thereby initiating an actuation of the fuel injection valve (10), characterized in that the control piston section (36) of the control piston (34) is guided with the control edge (45) in a control cylinder (41) which is arranged in the pressure space (40) of the valve body (31) and is separate from the sleeve (33).
  2. Fuel injector according to Claim 1, characterized in that a connecting duct (44) which interacts with the control edge (45) is formed in a guide region of the control piston section (36) in such a way that, in the deactivated state with the sealing seat (46) of the control piston (34) closed, there is a hydraulic connection between the pressure space (40) and the valve chamber (47).
  3. Fuel injector according to Claim 1 or 2, characterized in that the control cylinder (41) has a further sealing seat (42) which, in the pressure-relieved state of the valve chamber (47), separates the pressure space (40) from the valve chamber (47).
  4. Fuel injector according to Claim 1, 2 or 3, characterized in that a pressure spring (49) is provided which acts on the control cylinder (41) in the closing direction of the further sealing seat (42).
  5. Fuel injector according to Claim 1, characterized in that the control piston (34) has an opening pressure face (39) which is exposed to the pressure space (40), is acted on with system pressure and acts constantly in the opening direction on the sealing seat (46).
  6. Fuel injector according to Claim 1, characterized in that the pressure face (38) in the sleeve delimits a control space (37) which can be switched by means of a switching valve (50) between a connection to the system pressure and the low pressure or return system.
  7. Fuel injector according to Claim 1, characterized in that the sealing seat (46) of the control piston (34) is formed with a flat seat.
  8. Fuel injector according to one of the preceding claims, characterized in that the control cylinder (41) is externally acted on at least partially within the pressure space (40) with system pressure.
  9. Fuel injection device according to Claim 1, characterized in that a pressure booster device (20) which has a pressure booster piston (21) and is controlled by the control valve (30) is connected between the high pressure source (5) and the injection valve (10).
  10. Fuel injection device according to Claim 9, characterized in that the pressure booster device (20) has a rear space (26) which interacts with the pressure booster piston (21) and can be controlled by the control valve (30) so that a pressure boost acting on the injection valve (10) takes place as a result of a pressure change in the rear space (26).
EP05100659A 2004-04-08 2005-02-01 Fuel injector controlled by a servo valve Expired - Fee Related EP1584814B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102004017304A DE102004017304A1 (en) 2004-04-08 2004-04-08 Servo valve controlled fuel injector
DE102004017304 2004-04-08

Publications (2)

Publication Number Publication Date
EP1584814A1 EP1584814A1 (en) 2005-10-12
EP1584814B1 true EP1584814B1 (en) 2007-05-16

Family

ID=34895517

Family Applications (1)

Application Number Title Priority Date Filing Date
EP05100659A Expired - Fee Related EP1584814B1 (en) 2004-04-08 2005-02-01 Fuel injector controlled by a servo valve

Country Status (4)

Country Link
US (1) US7210639B2 (en)
EP (1) EP1584814B1 (en)
DE (2) DE102004017304A1 (en)
ES (1) ES2284123T3 (en)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3994990B2 (en) * 2004-07-21 2007-10-24 株式会社豊田中央研究所 Fuel injection device
JP4305394B2 (en) * 2005-01-25 2009-07-29 株式会社デンソー Fuel injection device for internal combustion engine
DE102006038840A1 (en) 2006-08-18 2008-02-21 Robert Bosch Gmbh Fuel injector with piston return of a pressure booster piston
US7568632B2 (en) * 2006-10-17 2009-08-04 Sturman Digital Systems, Llc Fuel injector with boosted needle closure
JP2009103080A (en) * 2007-10-24 2009-05-14 Denso Corp Fuel injection valve
DK177456B1 (en) * 2011-06-27 2013-06-17 Man Diesel & Turbo Deutschland A fuel valve for large turbocharged two stroke diesel engines
GB201518923D0 (en) 2015-10-27 2015-12-09 Delphi Internat Operations Luxembourg S À R L Control valve arrangement of a fuel injector
CN114405764B (en) * 2022-02-23 2022-11-29 无锡冰平自动化技术有限公司 Injecting glue body that disk seat die cavity stroke is the same

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10218904A1 (en) * 2001-05-17 2002-12-05 Bosch Gmbh Robert Fuel injection system

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2145080A5 (en) * 1971-07-08 1973-02-16 Peugeot & Renault
US5669355A (en) * 1994-07-29 1997-09-23 Caterpillar Inc. Hydraulically-actuated fuel injector with direct control needle valve
US5687693A (en) * 1994-07-29 1997-11-18 Caterpillar Inc. Hydraulically-actuated fuel injector with direct control needle valve
US5975139A (en) * 1998-01-09 1999-11-02 Caterpillar Inc. Servo control valve for a hydraulically-actuated device
DE10123917A1 (en) * 2001-05-17 2002-11-28 Bosch Gmbh Robert Fuel injection system for internal combustion engine has closure piston region protruding into closure pressure chamber connected to high-pressure source so source fuel pressure acts on closure piston
DE10123911A1 (en) * 2001-05-17 2002-11-28 Bosch Gmbh Robert Fuel injection device for internal combustion engine has transfer piston separating chamber connected to source from high pressure and return chambers
DE10123914B4 (en) * 2001-05-17 2005-10-20 Bosch Gmbh Robert Fuel injection device with pressure booster device and pressure booster device
DE10229418A1 (en) * 2002-06-29 2004-01-29 Robert Bosch Gmbh Device for damping the needle stroke on fuel injectors
JP2006522254A (en) * 2003-04-02 2006-09-28 ローベルト　ボツシユ　ゲゼルシヤフト　ミツト　ベシユレンクテル　ハフツング Servo valve controlled fuel injector with intensifier
DE10337574A1 (en) * 2003-08-14 2005-03-10 Bosch Gmbh Robert Fuel injection device for internal combustion engines

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10218904A1 (en) * 2001-05-17 2002-12-05 Bosch Gmbh Robert Fuel injection system

Also Published As

Publication number Publication date
ES2284123T3 (en) 2007-11-01
US7210639B2 (en) 2007-05-01
DE502005000719D1 (en) 2007-06-28
EP1584814A1 (en) 2005-10-12
DE102004017304A1 (en) 2005-10-27
US20050224599A1 (en) 2005-10-13

Similar Documents

Publication Publication Date Title
EP1654455B1 (en) Control valve for a fuel injector that contains a pressure intensifier
EP1688611B1 (en) Fuel injector with direct needle control for an internal combustion engine
EP1584814B1 (en) Fuel injector controlled by a servo valve
EP1379775B1 (en) Valve for controlling liquids
EP1507082B1 (en) Fuel injection system for combustion engine
DE10315015B4 (en) Fuel injector with pressure booster and servo valve with optimized control quantity
EP1651862B1 (en) Control valve for a fuel injector comprising a pressure exchanger
EP1363015A1 (en) Fuel injection system for an internal combustion engine
EP1899597A1 (en) Injector with a pressure intensifier that can be switched on
EP1651861B1 (en) Control valve with pressure compensation for a fuel injector comprising a pressure intensifier
EP1925812B1 (en) Fuel injector valve for combustion engines
EP1682769B1 (en) Fuel injector with a multipart, directly controlled injection valve element
EP1421272B1 (en) Fuel-injection device for internal combustion engines
DE10141221B4 (en) Pressure-stroke controlled injector for fuel injection systems
EP1491757B1 (en) Fuel injection system for internal combustion engine
DE10160264A1 (en) Fuel injection device for internal combustion engine has smaller cross-section of connection to relief chamber exposed with increased injection valve element opening displacement
EP1961953A1 (en) Multiway valve
DE102007002759A1 (en) Fuel injector for injecting fuel into combustion chamber of internal combustion engine, has intermediate plate with step drill arranged between injector and nozzle bodies, and control and closing spaces, which are formed in step drill
DE10101802A1 (en) Valve for controlling liquids e.g. fuel injection valve in IC engine, has actuating piston movably arranged in control piston blind bore to bound hydraulic chamber, with actuating piston and valve closure element made in one piece
DE10050599B4 (en) Injection valve with a pump piston
DE10145822B4 (en) A fuel injector injector
DE10233574B4 (en) Valve for controlling fluids
EP1317621A1 (en) Hydraulically translated valve
DE102006027484A1 (en) Fuel injector for an internal combustion motor, with a common rail fuel injection system, has the armature of the magnetic setting unit in the equalizing zone with the control piston pressure surface to reduce injector height
DE102004038189A1 (en) Fuel injector linked to a high pressure fuel supply, for an IC motor, has an inner and a coaxial outer needle with separate control zones and switch valves

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU MC NL PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL BA HR LV MK YU

17P Request for examination filed

Effective date: 20060412

AKX Designation fees paid

Designated state(s): DE ES FR IT

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE ES FR IT

REF Corresponds to:

Ref document number: 502005000719

Country of ref document: DE

Date of ref document: 20070628

Kind code of ref document: P

ET Fr: translation filed
REG Reference to a national code

Ref country code: ES

Ref legal event code: FG2A

Ref document number: 2284123

Country of ref document: ES

Kind code of ref document: T3

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed

Effective date: 20080219

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: ES

Payment date: 20140220

Year of fee payment: 10

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 11

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: IT

Payment date: 20150223

Year of fee payment: 11

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20150217

Year of fee payment: 11

REG Reference to a national code

Ref country code: ES

Ref legal event code: FD2A

Effective date: 20160329

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20150202

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20161028

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20160201

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20160229

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20170427

Year of fee payment: 13

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 502005000719

Country of ref document: DE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20180901