EP2126333B1 - Fuel injector comprising a coupler - Google Patents

Fuel injector comprising a coupler Download PDF

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Publication number
EP2126333B1
EP2126333B1 EP07858229A EP07858229A EP2126333B1 EP 2126333 B1 EP2126333 B1 EP 2126333B1 EP 07858229 A EP07858229 A EP 07858229A EP 07858229 A EP07858229 A EP 07858229A EP 2126333 B1 EP2126333 B1 EP 2126333B1
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EP
European Patent Office
Prior art keywords
coupler
valve member
injection valve
fuel injector
valve piston
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EP07858229A
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German (de)
French (fr)
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EP2126333A1 (en
Inventor
Andreas Kellner
Holger Rapp
Martin Katz
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Robert Bosch GmbH
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Robert Bosch GmbH
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Publication of EP2126333A1 publication Critical patent/EP2126333A1/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M51/00—Fuel-injection apparatus characterised by being operated electrically
    • F02M51/06—Injectors peculiar thereto with means directly operating the valve needle
    • F02M51/0603—Injectors peculiar thereto with means directly operating the valve needle using piezoelectric or magnetostrictive operating means
    • 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
    • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/04—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00 having valves, e.g. having a plurality of valves in series
    • F02M61/10—Other injectors with elongated valve bodies, i.e. of needle-valve type
    • F02M61/12—Other injectors with elongated valve bodies, i.e. of needle-valve type characterised by the provision of guiding or centring means for valve bodies
    • 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
    • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
    • F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
    • F02M61/167—Means for compensating clearance or thermal expansion

Definitions

  • Out DE 196 50 865 A1 is a solenoid valve for controlling the fuel pressure in a control chamber of an injection valve, such as for a common rail injection system, known. Via the fuel pressure in the control chamber, a stroke movement of a valve piston is controlled, with which an injection opening of the injection valve is opened or closed.
  • the solenoid valve comprises an electromagnet, a movable armature and a valve member which is moved with the armature and acted upon by a valve closing spring in the closing direction, which cooperates with the valve seat of the solenoid valve and thus controls the fuel drain from a control chamber.
  • a fuel injector which has a coupler, with which the force of a piezoelectric actuator is transmitted to a valve needle by the piezoelectric actuator moves a coupler piston and the movement of the coupler piston is transmitted through a fuel-filled coupler space on the valve needle.
  • the hydraulic coupler comprises a coupler sleeve with an internal bore in which the valve piston is guided.
  • the diameter of the coupler sleeve is larger than the outer diameter of the needle-shaped injection valve member.
  • the coupler sleeve rests on a nozzle body at its lower end with a sealing edge formed on its end face and thus encloses a coupler volume.
  • the coupler sleeve is employed in the idle state with a small, applied via a coil spring force to an end face of the nozzle needle.
  • the coupler sleeve or the coupler is surrounded by fuel under system pressure.
  • system pressure is meant the fuel pressure level generated in a fuel injection system, such as via a high pressure pump, within a high pressure reservoir body (common rail).
  • valve piston If the fuel injector is activated, the valve piston first moves upwards. This upward movement creates a negative pressure in the coupler volume compared to the external system pressure level. Due to the negative pressure follows the needle-shaped formed injection valve member to the valve piston and, as a result, rests again on its front side opposite the preferred needle-shaped injection valve member. As the valve piston stroke increases, the pressure in the coupler volume decreases because, due to the difference in diameter between the inner bore of the coupler sleeve and the outer diameter of the needle-shaped injection valve member, the available fuel volume in the coupler increases. After the end of the control, the valve piston and the needle-shaped injection valve member move back in the closing direction downwards.
  • the coupler sleeve on the valve piston with a comparatively large guide clearance on the order of a few microns, z. B. 8 microns, and over a length of a few mm, such. B. 5 mm, out.
  • the inner diameter of the coupler sleeve is about 3.8 mm and the outer diameter of the needle-shaped injection valve member is 3.5 mm.
  • a leak-free fuel injector which by means of an actuator, such as. B. a solenoid valve, is operable, wherein the difference in diameter between the inner diameter of the coupler sleeve and the outer diameter of the preferably needle-shaped injection valve member is not more than 0.2 mm.
  • the guide play between the injection valve member enclosing the coupler sleeve and the valve piston guided therein is reduced, in particular to a value of a few microns, such. B. to values of less than 5 microns. Due to the fact that the inflow volume flow is proportional to the pressure difference over the guide length but inversely proportional to the third power of the guide game, this measure is highly effective in terms of the flow of fuel into the coupler.
  • the guide length between the coupling needle sleeve which surrounds the preferably needle-shaped injection valve member and the needle-shaped injection valve member can be increased to values of more than 5 mm. Since the time delay until the needle-shaped injection valve member opens increases more and more as the volume of the coupler increases, the volume of the coupler remains limited to ⁇ 40 mm 3 in the idle state.
  • the subsequent flow of fuel into the coupler is largely reduced by the solution proposed by the invention during the injection process.
  • the volume of fuel contained in the coupler or the dead volume present there is kept small without the fuel afterflow in order to achieve the most direct possible coupling of the valve needle to reach with the valve piston.
  • a transition region is formed on the valve piston of the coupler, within which the diameter of the valve piston passes in a diameter corresponding to the diameter of a bore formed in the nozzle body, in which the injection valve member is guided with the outer diameter.
  • FIG. 1 is an embodiment of a coupler for a fuel injector according to the prior art can be seen.
  • FIG. 1 shows that a fuel injector 10 comprises a particular needle-shaped injection valve member 12.
  • the needle-shaped injection valve member 12 is guided in a bore 14 of a nozzle body 18.
  • the fuel injector 10 includes a cavity 16 in which system pressure p sys prevails.
  • the system pressure p sys corresponds to a pressure level which z. B. by a high pressure pumping unit in a storage body (common rail) is generated.
  • the nozzle body 18 comprises a bore 14, in which the particular needle-shaped injection valve member 12 is guided, and which has an end face 20.
  • An axis of the particular needle-shaped injection valve member 12 is denoted by reference numeral 22 and extends coaxially to the axis of a valve piston 24.
  • the valve piston 24 includes an end face 26 which faces an end face 28 of the particular needle-shaped injection valve member 12.
  • the valve piston 24 is enclosed by a coupler sleeve 30.
  • the coupler which comprises the valve piston 24 and the coupler sleeve 30 surrounding it, the stroke movement of an actuator, such as an electromagnet, for example or a piezoelectric actuator, to which in particular needle-shaped injection valve member 12 transmit.
  • an actuator such as an electromagnet, for example or a piezoelectric actuator
  • the coupler sleeve 30 comprises a first end face 32 and a second end face 34.
  • a biting edge 36 is formed on the second end face 34 of the coupler sleeve 30. With the biting edge 36, the coupler sleeve 30 is set against the end face 20 of the nozzle body 18.
  • the coupler sleeve 30 is a in FIG. 1 not shown biasing element acted upon by a biasing force. From the illustration according to FIG. 1 It can be seen that the valve piston 24, which is part of the hydraulic coupler, comprises a constriction 38.
  • the in FIG. 1 shown fuel injector 10 has between the inner diameter of the coupler sleeve 30 and the outer diameter of the injection valve member 12 has a diameter difference in the order of 0.3 mm.
  • This guide clearance leads to a lag of the coupler pressure with respect to the system pressure p sys by about 100 ⁇ s. Due to the guide clearance, which results from the difference in diameter in the order of 0.3 mm, runs during the lifting movement of the valve piston 24, a fuel quantity after. Since the coupler sleeve 30 lifts off after each injection of the end face 20 of the nozzle body 18, the coupler sleeve 30 is found after each injection a slightly different position, wherein the shape of the guide gap changes from injection to injection process.
  • the amount of fuel flowing into the coupler volume influences the closing movement and the closing time of the preferably needle-shaped injection valve member 12, which leads to lift / stroke spreads that are significantly greater compared to conventional injectors.
  • the valve piston is surrounded by fuel at low pressure (low pressure). This results in a continuous leakage from the control chamber along the valve piston guide on the one hand and from the high-pressure chamber along the injection valve member along the guide of the injection valve member in the surrounding the valve piston volume.
  • the volume surrounding the valve piston is connected to the high pressure area.
  • the leakage is omitted due to the lack of a pressure gradient on the guides of the relatively movable components.
  • FIG. 2 The representation according to FIG. 2 is a section through a proposed inventions coupler.
  • the needle-shaped injection valve member 12 includes, which is guided in the bore 14 of the nozzle body 18.
  • pressure p sys prevails.
  • the coupler sleeve 30 is employed at the end face 20 of the nozzle body 18. Their first end face is indicated by reference numeral 32 and the second end face by reference numeral 34.
  • Coupler sleeve 30 shown has the coupler sleeve 30 used in accordance with the invention proposed fuel injector 10 has a substantially rectangular cross-section.
  • the axis of the preferably needle-shaped injection valve member 12 is designated by reference numeral 22.
  • the biting edge 36 is located on the second end face 34 of the coupler sleeve 30, which has a substantially rectangular cross-section.
  • the coupler sleeve 30 is set against the end face 20 of the nozzle body 18 due to the effect of an adjusting force 50. From the illustration according to FIG. 2 moreover, it is apparent that a guide play 40 between the inner diameter 46 of the coupler sleeve 30 and the outer diameter of the valve piston 24 is ⁇ 5 ⁇ m.
  • the valve piston 24 has in the region, ie its guide length 58, in which this is guided in the coupler sleeve 30, the diameter 46, taking into account the guide clearance 40 of ⁇ 5 microns on the coupler sleeve 30.
  • a transition region 42nd indicated within which the diameter of the valve piston 24 merges into a diameter which corresponds to the diameter of the nozzle body 18 formed in the bore 14 and which corresponds substantially to the outer diameter 44 of the injection valve member 12. From the illustration according to FIG. 2 shows that in the illustrated stage of the lifting phase of the preferably needle-shaped injection valve member 12 and the valve piston 24 of the coupler, the end face 26 of the valve piston 24 abuts an end face 28 of the preferably needle-shaped injection valve member 12.
  • a coupler space 54 is formed, which has a coupler volume which is of the order of ⁇ 40 mm 3 .
  • the bore 14, in which a part of the valve piston 24 of the coupler and the preferably needle-shaped injection valve member 12 in Nozzle body 18 are guided, has a chamfer 52 on the end face 20.
  • a bevel 56 may be formed on the end face 26 of the valve piston 24 of the coupler.
  • the end faces 26 and 28 of the valve piston 24 or preferably needle-shaped injection valve member 12 executed plan.
  • 2 shown Kraftstoffinjektor 10 has on the one hand a difference in diameter between the inner diameter 46 of the coupler sleeve 30 and the outer diameter 44 of the preferably needle-shaped injection valve member 12 between 0.2 mm and 0 mm. Because of this small remaining difference in diameter, the pressure drop within the coupler during the lifting movement of the preferably needle-shaped injection valve member 12 is reduced. If the difference in diameter between the inner diameter 46 of the coupler sleeve 30 and the outer diameter 44 of the preferably needle-shaped injection valve member 12 0 mm, creates a pressure difference ⁇ p only during the lifting of the preferably needle-shaped injection valve member 12 from its seat and disappears again as soon as the preferably needle-shaped Injector valve member has left the seat throttle area.
  • the guide clearance 50 between the coupler sleeve 30 and the valve piston 24 is reduced to values ⁇ 5 ⁇ m, so that the volume flow flowing in via the reduced guide clearance 50 into the coupler space 54 is effectively reduced. Furthermore - as in FIG. 2 shown - the guide length 58, within which the valve piston 24 of the coupler is guided in the coupler sleeve 30, in comparison to in FIG. 1 shown guide length considerably extended. In order to achieve a lag-free as possible lagging the preferably needle-shaped injection valve member 12 relative to the valve piston 24, the fuel volume within the coupler sleeve 30 in the closed state of the fuel injector to values ⁇ 40 mm 3 is limited.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Fuel-Injection Apparatus (AREA)
  • Feeding And Controlling Fuel (AREA)

Abstract

The invention relates to a fuel injector having a coupler. The reciprocating movement of an actuator is transmitted by the coupler to a pin-shaped injection valve member which is guided into the nozzle body. The coupler has a valve piston and a coupler sleeve, and the valve piston is displaced in the inner diameter area of the coupler sleeve. The inner diameter of the coupler sleeve is greater than the outer diameter of the injection valve member. The difference between the inner diameter of the coupler housing and the outer diameter of the injection valve member is 0.2 mm or less.

Description

Stand der TechnikState of the art

Aus DE 196 50 865 A1 ist ein Magnetventil zur Steuerung des Kraftstoffdruckes in einem Steuerraum eines Einspritzventiles, so zum Beispiel für ein Common-Rail-Einspritzsystem, bekannt. Über den Kraftstoffdruck im Steuerraum wird eine Hubbewegung eines Ventilkolbens gesteuert, mit dem eine Einspritzöffnung des Einspritzventiles geöffnet oder geschlossen wird. Das Magnetventil umfasst einen Elektromagneten, einen beweglichen Anker und ein mit dem Anker bewegtes und von einer Ventilschließfeder in Schließrichtung beaufschlagtes Ventilglied, das mit dem Ventilsitz des Magnetventiles zusammenwirkt und so den Kraftstoffabfluss aus einem Steuerraum steuert.Out DE 196 50 865 A1 is a solenoid valve for controlling the fuel pressure in a control chamber of an injection valve, such as for a common rail injection system, known. Via the fuel pressure in the control chamber, a stroke movement of a valve piston is controlled, with which an injection opening of the injection valve is opened or closed. The solenoid valve comprises an electromagnet, a movable armature and a valve member which is moved with the armature and acted upon by a valve closing spring in the closing direction, which cooperates with the valve seat of the solenoid valve and thus controls the fuel drain from a control chamber.

Aus der WO 2006/008200 A1 ist darüber hinaus ein Kraftstoffinjektor bekannt, der einen Koppler aufweist, mit dem die Kraft eines Piezoaktors auf eine Ventilnadel übertragen wird, indem der Piezoaktor einen Kopplerkolben bewegt und die Bewegung des Kopplerkolbens durch einen kraftstoffgefüllten Kopplerraum auf die Ventilnadel übertragen wird.From the WO 2006/008200 A1 In addition, a fuel injector is known, which has a coupler, with which the force of a piezoelectric actuator is transmitted to a valve needle by the piezoelectric actuator moves a coupler piston and the movement of the coupler piston is transmitted through a fuel-filled coupler space on the valve needle.

Bei einem derzeit eingesetzten, leckagefreien Kraftstoffinjektor, der mittels eines Magnetventiles betätigt wird, erfolgt die Kopplung zwischen einem Ventilkolben und einem nadelförmig ausgebildeten Einspritzventilglied über einen hydraulischen Koppler. Der hydraulische Koppler umfasst eine Kopplerhülse mit einer Innenbohrung, in welcher der Ventilkolben geführt ist. Der Durchmesser der Kopplerhülse ist größer als der Außendurchmesser des nadelförmig ausgebildeten Einspritzventilgliedes. Die Kopplerhülse liegt an ihrem unteren Ende mit einer an deren Stirnseite ausgebildeten Dichtkante auf einem Düsenkörper auf und schließt somit ein Kopplervolumen ein. Die Kopplerhülse wird im Ruhezustand mit einer geringen, über eine Spiralfeder aufgebrachten Kraft an eine Stirnfläche der Düsennadel angestellt. Die Kopplerhülse beziehungsweise der Koppler ist von unter Systemdruck stehendem Kraftstoff umgeben. Unter Systemdruck ist das Kraftstoffdruckniveau zu verstehen, welches in einem Kraftstoffeinspritzsystem, so zum Beispiel über eine Hochdruckpumpe, innerhalb eines Hochdruckspeicherkörpers (Common-Rail) erzeugt wird.In a currently used, leak-free Kraftstoffinjektor which is actuated by means of a solenoid valve, the coupling between a valve piston and a needle-shaped injection valve member via a hydraulic coupler. The hydraulic coupler comprises a coupler sleeve with an internal bore in which the valve piston is guided. The diameter of the coupler sleeve is larger than the outer diameter of the needle-shaped injection valve member. The coupler sleeve rests on a nozzle body at its lower end with a sealing edge formed on its end face and thus encloses a coupler volume. The coupler sleeve is employed in the idle state with a small, applied via a coil spring force to an end face of the nozzle needle. The coupler sleeve or the coupler is surrounded by fuel under system pressure. By system pressure is meant the fuel pressure level generated in a fuel injection system, such as via a high pressure pump, within a high pressure reservoir body (common rail).

Wird der Kraftstoffinjektor angesteuert, so bewegt sich zunächst der Ventilkolben nach oben. Durch diese Aufwärtsbewegung entsteht ein Unterdruck im Kopplervolumen gegenüber dem außenliegenden Systemdruckniveau. Aufgrund des Unterdruckes folgt das nadelförmig ausgebildete Einspritzventilglied dem Ventilkolben und legt sich infolgedessen wieder an dessen dem bevorzugt nadelförmig ausgebildeten Einspritzventilglied gegenüberliegenden Stirnseite an. Bei größer werdendem Ventilkolbenhub sinkt der Druck im Kopplervolumen, da infolge des Durchmesserunterschiedes zwischen der Innenbohrung der Kopplerhülse und dem Außendurchmesser des nadelförmig ausgebildeten Einspritzventilgliedes das zur Verfügung stehende Kraftstoffvolumen im Koppler steigt. Nach Ende der Ansteuerung bewegen sich der Ventilkolben und das nadelförmig ausgebildete Einspritzventilglied wieder in Schließerichtung abwärts. Nähert sich das nadelförmig ausgebildete Einspritzventilglied seinem Sitz, so sinkt die von unten auf das nadelförmig ausgebildete Einspritzventilglied wirkende hydraulische Kraft, und das nadelförmige Einspritzventilglied eilt dem Ventilkolben in Schließrichtung voraus. Aufgrund des Umstandes, dass während der Hubbewegung über das Führungsspiel Kraftstoff in das Kopplervolumen nachgeströmt ist, erreicht der Druck im Koppler den Systemdruck bereits, bevor der Ventilkolben wieder auf der Stirnseite des nadelförmig ausgebildeten Einspritzventilgliedes aufliegt. Folglich entsteht innerhalb des Kopplers ein Überdruck, durch den die Kopplerhülse gegen die geringe Vorspannkraft von der Stirnseite des Düsenkörpers abgehoben wird, an den sie angestellt ist, so dass das nachgeströmte Volumen wieder entweicht.If the fuel injector is activated, the valve piston first moves upwards. This upward movement creates a negative pressure in the coupler volume compared to the external system pressure level. Due to the negative pressure follows the needle-shaped formed injection valve member to the valve piston and, as a result, rests again on its front side opposite the preferred needle-shaped injection valve member. As the valve piston stroke increases, the pressure in the coupler volume decreases because, due to the difference in diameter between the inner bore of the coupler sleeve and the outer diameter of the needle-shaped injection valve member, the available fuel volume in the coupler increases. After the end of the control, the valve piston and the needle-shaped injection valve member move back in the closing direction downwards. When the needle-shaped injection valve member approaches its seat, the hydraulic force acting from below on the needle-shaped injection valve member decreases, and the needle-shaped injection valve member leads the valve piston in the closing direction. Due to the fact that fuel has flowed into the coupler volume during the lifting movement via the guide clearance, the pressure in the coupler already reaches the system pressure before the valve piston rests again on the end face of the needle-shaped injection valve member. Consequently, within the coupler, an overpressure, by which the coupler sleeve is lifted against the small biasing force of the end face of the nozzle body to which it is employed, so that the nachgeströmte volume escapes again.

Um dynamische Druckunterschiede zwischen dem Kopplervolumen und dem umgebenden Kraftstoff zu vermeiden, ist die Kopplerhülse auf dem Ventilkolben mit einem vergleichsweise großen Führungsspiel in der Größenordnung von einigen µm, z. B. 8 µm, und auf einer Länge von einigen mm, so z. B. 5 mm, geführt. Der Innendurchmesser der Kopplerhülse beträgt etwa 3,8 mm und der Außendurchmesser des nadelförmig ausgebildeten Einspritzventilgliedes 3,5 mm. Diese Auslegung führt zu einem Nacheilen des Kopplerdrucks gegenüber dem Systemdruck im Ruhezustand in der Größenordnung von 100 µs. Über dieses Spiel läuft während der Hubbewegung des Ventilkolbens - wie oben erwähnt - eine Kraftstoffmenge nach. Da die Kopplerhülse nach jeder Einspritzung von ihrer Auflagefläche auf den Düsenkörper abhebt, findet diese Hülse nach jeder Einspritzung eine geringfügig andere Lage, und die Form des Führungsspaltes (Sichelspalt - Ringspalt) ändert sich von Einspritzvorgang zu Einspritzvorgang. Folglich ändert sich auch die während der Hubbewegung in den Koppler nachlaufende Menge von Einspritzung zu Einspritzung. Besonders groß können diese Unterschiede dann werden, wenn die nachlaufende Kraftstoffmenge pro Einspritzung groß ist, was insbesondere bei großem Hub des nadelförmig ausgebildeten Einspritzventilgliedes und hohem Systemdruck der Fall ist. Da das nachgeströmte Kraftstoffvolumen die Schließbewegung und den Schließzeitpunkt des Einspritzventilgliedes beeinflusst, führt dieser Vorgang schließlich zu Hub/Hub-Streuungen der Einspritzmenge, die relativ groß sind.To avoid dynamic pressure differences between the coupler volume and the surrounding fuel, the coupler sleeve on the valve piston with a comparatively large guide clearance on the order of a few microns, z. B. 8 microns, and over a length of a few mm, such. B. 5 mm, out. The inner diameter of the coupler sleeve is about 3.8 mm and the outer diameter of the needle-shaped injection valve member is 3.5 mm. This design leads to a lag of the coupler pressure against the system pressure at rest in the order of 100 microseconds. About this game runs during the lifting movement of the valve piston - as mentioned above - a quantity of fuel after. Since the coupler sleeve lifts off from its bearing surface on the nozzle body after each injection, this sleeve finds a slightly different position after each injection, and the shape of the guide gap (sickle gap - annular gap) changes from injection to injection. Consequently, the amount of injection trailing to the coupler during stroke movement also changes from injection to injection. These differences can be particularly large when the trailing fuel quantity per injection is large, which is the case in particular with a large stroke of the needle-shaped injection valve member and high system pressure. Finally, since the amount of fuel that has flowed affects the closing movement and the closing timing of the injection valve member, this process results in injection stroke-stroke spreads that are relatively large.

Offenbarung der ErfindungDisclosure of the invention

Erfindungsgemäß wird ein leckagefreier Kraftstoffinjektor vorgeschlagen, der mittels eines Aktors, wie z. B. eines Magnetventils, betätigbar ist, bei dem der Durchmesserunterschied zwischen dem Innendurchmesser der Kopplerhülse und dem Außendurchmesser des bevorzugt nadelförmig ausgebildeten Einspritzventilgliedes nicht mehr als 0,2 mm beträgt. Durch diese Reduzierung des Durchmesserunterschiedes zwischen dem Außendurchmesser des bevorzugt nadelförmig ausgebildeten Einspritzventilgliedes und dem Innendurchmesser der dieses umgebenden Kopplerraumhülse wird der Druckabfall im Koppler während der Hubbewegung reduziert. Beträgt der Durchmesserunterschied zwischen dem Innendurchmesser der Kopplerhülse und dem Außendurchmesser des nadelförmig ausgebildeten Einspritzventilgliedes 0, entsteht ein Druckunterschied nur noch während des Abhebens des bevorzugt nadelförmig ausgebildeten Einspritzventilgliedes aus dem Düsensitz und wird wieder zu 0, sobald das nadelförmig ausgebildete Einspritzventilglied den Sitzdrosselbereich verlassen hat. Ein geringer Durchmesserunterschied ist jedoch notwendig, um zur hydraulischen Kopplung zwischen dem Ventilkolben und dem Einspritzventilglied eine hydraulisch vorgespannte Feder zu realisieren.According to the invention, a leak-free fuel injector is proposed which by means of an actuator, such as. B. a solenoid valve, is operable, wherein the difference in diameter between the inner diameter of the coupler sleeve and the outer diameter of the preferably needle-shaped injection valve member is not more than 0.2 mm. As a result of this reduction in the diameter difference between the outer diameter of the preferably needle-shaped injection valve member and the inner diameter of the surrounding coupler space sleeve, the pressure drop in the coupler is reduced during the lifting movement. If the difference in diameter between the inner diameter of the coupler sleeve and the outer diameter of the needle-shaped injection valve member 0, a pressure difference arises only during the lifting of the preferably needle-shaped injection valve member from the nozzle seat and becomes 0 again as soon as the needle-shaped injection valve member has left the seat throttle range. However, a small difference in diameter is necessary to realize a hydraulic preloaded spring for hydraulic coupling between the valve piston and the injection valve member.

Des Weiteren ist vorteilhaft, wenn das Führungsspiel zwischen der das Einspritzventilglied umschließenden Kopplerhülse und dem darin geführten Ventilkolbenreduziert ist, insbesondere auf einen Werte von einigen µm, so z. B. auf Werte von weniger als 5 µm. Aufgrund des Umstandes, dass der nachströmende Volumenstrom proportional zum Druckunterschied über der Führungslänge jedoch umgekehrt proportional zur dritten Potenz des Führungsspieles ist, ist diese Maßnahme höchst wirkungsvoll, was das Nachströmen von Kraftstoff in den Koppler betrifft. Schließlich kann optional die Führungslänge zwischen der das bevorzugt nadelförmig ausgebildete Einspritzventilglied umgebenden Kopplerhülse und dem nadelförmig ausgebildeten Einspritzventilglied auf Werte von mehr als 5 mm gesteigert werden. Da mit zunehmendem Kopplervolumen im Ruhezustand die Zeitverzögerung bis zum Öffnen des nadelförmig ausgebildeten Einspritzventilgliedes immer mehr ansteigt, bleibt das Kopplervolumen im Ruhezustand auf Werte < 40 mm3 begrenzt.Furthermore, it is advantageous if the guide play between the injection valve member enclosing the coupler sleeve and the valve piston guided therein is reduced, in particular to a value of a few microns, such. B. to values of less than 5 microns. Due to the fact that the inflow volume flow is proportional to the pressure difference over the guide length but inversely proportional to the third power of the guide game, this measure is highly effective in terms of the flow of fuel into the coupler. Finally, optionally the guide length between the coupling needle sleeve which surrounds the preferably needle-shaped injection valve member and the needle-shaped injection valve member can be increased to values of more than 5 mm. Since the time delay until the needle-shaped injection valve member opens increases more and more as the volume of the coupler increases, the volume of the coupler remains limited to <40 mm 3 in the idle state.

Das Nachströmen von Kraftstoff in den Koppler wird durch die erfindungsgemäß vorgeschlagene Lösung während des Einspritzvorgangs weitestgehend reduziert. Das im Koppler enthaltene Kraftstoffvolumen bzw. das dort vorhandene Totvolumen wird ohne das Kraftstoffnachströmen klein gehalten, um eine möglichst direkte Kopplung der Ventilnadel mit dem Ventilkolben zu erreichen. Dadurch dass die Umgebung des Koppers vom Systemdruck umgeben ist, ist der Kraftstoffinjektor leckagefrei ausgeführt.The subsequent flow of fuel into the coupler is largely reduced by the solution proposed by the invention during the injection process. The volume of fuel contained in the coupler or the dead volume present there is kept small without the fuel afterflow in order to achieve the most direct possible coupling of the valve needle to reach with the valve piston. The fact that the environment of the Koppers is surrounded by the system pressure, the fuel injector is carried out leak-free.

Erfindungsgemäss ist am Ventilkolben des Kopplers ein Übergangsbereich ausgebildet, innerhalb dessen der Durchmesser des Ventilkolbens in einem Durchmesser übergeht, der dem Durchmesser einer im Düsenkörper ausgebildeten Bohrung entspricht, in welcher das Einspritzventilglied mit dem Aussendurchmesser geführt ist.According to the invention a transition region is formed on the valve piston of the coupler, within which the diameter of the valve piston passes in a diameter corresponding to the diameter of a bore formed in the nozzle body, in which the injection valve member is guided with the outer diameter.

Kurze Beschreibung der ZeichnungenBrief description of the drawings

Anhand der Zeichnung wird die Erfindung nachfolgend eingehender beschrieben.Reference to the drawings, the invention will be described below in more detail.

Es zeigt:

Figur 1
einen Kraftstoffinjektor aus dem Stande der Technik mit einer Kopplung zwi- schen dem Ventilkolben eines Kopplers und einem nadelförmig ausgebildeten Einspritzventilglied und
Figur 2
die erfindungsgemäß vorgeschlagene Ausgestaltung einer hydraulischen Kopplung zwischen einem Ventilkolben eines Kopplers und einem insbeson- dere nadelförmig ausgebildeten Einspritzventilglied.
It shows:
FIG. 1
a fuel injector of the prior art with a coupling between the valve piston of a coupler and a needle-shaped injection valve member and
FIG. 2
the inventively proposed embodiment of a hydraulic coupling between a valve piston of a coupler and an in particular needle-shaped injection valve member.

Ausführungsformenembodiments

Der Darstellung gemäß Figur 1 ist eine Ausführungsform eines Kopplers für einen Kraftstoffinjektor gemäß des Standes der Technik zu entnehmen.The representation according to FIG. 1 is an embodiment of a coupler for a fuel injector according to the prior art can be seen.

Aus Figur 1 geht hervor, dass ein Kraftstoffinjektor 10 ein insbesondere nadelförmig ausgebildetes Einspritzventilglied 12 umfasst. Das nadelförmig ausgebildete Einspritzventilglied 12 ist in einer Bohrung 14 eines Düsenkörpers 18 geführt. Der Kraftstoffinjektor 10 umfasst einen Hohlraum 16, in dem Systemdruck psys herrscht. Der Systemdruck psys entspricht einem Druckniveau, welches z. B. durch ein Hochdruckförderaggregat in einem Speicherkörper (Common-Rail) erzeugt wird. Der Düsenkörper 18 umfasst eine Bohrung 14, in der das insbesondere nadelförmig ausgebildete Einspritzventilglied 12 geführt ist, und welche eine Stirnseite 20 aufweist. Eine Achse des insbesondere nadelförmig ausgebildeten Einspritzventilgliedes 12 ist durch Bezugszeichen 22 bezeichnet und verläuft koaxial zu der Achse eines Ventilkolbens 24. Der Ventilkolben 24 umfasst eine Stirnseite 26, die einer Stirnseite 28 des insbesondere nadelförmig ausgebildeten Einspritzventilgliedes 12 gegenüberliegt. Der Ventilkolben 24 ist von einer Kopplerhülse 30 umschlossen.Out FIG. 1 shows that a fuel injector 10 comprises a particular needle-shaped injection valve member 12. The needle-shaped injection valve member 12 is guided in a bore 14 of a nozzle body 18. The fuel injector 10 includes a cavity 16 in which system pressure p sys prevails. The system pressure p sys corresponds to a pressure level which z. B. by a high pressure pumping unit in a storage body (common rail) is generated. The nozzle body 18 comprises a bore 14, in which the particular needle-shaped injection valve member 12 is guided, and which has an end face 20. An axis of the particular needle-shaped injection valve member 12 is denoted by reference numeral 22 and extends coaxially to the axis of a valve piston 24. The valve piston 24 includes an end face 26 which faces an end face 28 of the particular needle-shaped injection valve member 12. The valve piston 24 is enclosed by a coupler sleeve 30.

Mittels des Kopplers, welcher den Ventilkolben 24 sowie die diesen umschließende Kopplerhülse 30 umfasst, wird die Hubbewegung eines Aktors, so beispielsweise eines Elektromagneten oder eines Piezoaktors, an das insbesondere nadelförmig ausgebildete Einspritzventilglied 12 übertragen.By means of the coupler, which comprises the valve piston 24 and the coupler sleeve 30 surrounding it, the stroke movement of an actuator, such as an electromagnet, for example or a piezoelectric actuator, to which in particular needle-shaped injection valve member 12 transmit.

Die Kopplerhülse 30 umfasst eine erste Stirnseite 32 sowie eine zweite Stirnseite 34. An der zweiten Stirnseite 34 der Kopplerhülse 30 ist eine Beißkante 36 ausgebildet. Mit der Beißkante 36 ist die Kopplerhülse 30 an die Stirnseite 20 des Düsenkörpers 18 angestellt. Die Kopplerhülse 30 ist über ein in Figur 1 nicht dargestelltes Vorspannelement mit einer Vorspannkraft beaufschlagt. Aus der Darstellung gemäß Figur 1 geht hervor, dass der Ventilkolben 24, der Bestandteil des hydraulischen Kopplers ist, eine Einschnürung 38 umfasst.The coupler sleeve 30 comprises a first end face 32 and a second end face 34. A biting edge 36 is formed on the second end face 34 of the coupler sleeve 30. With the biting edge 36, the coupler sleeve 30 is set against the end face 20 of the nozzle body 18. The coupler sleeve 30 is a in FIG. 1 not shown biasing element acted upon by a biasing force. From the illustration according to FIG. 1 It can be seen that the valve piston 24, which is part of the hydraulic coupler, comprises a constriction 38.

Der in Figur 1 dargestellte Kraftstoffinjektor 10 weist zwischen dem Innendurchmesser der Kopplerhülse 30 und dem Außendurchmesser des Einspritzventilgliedes 12 eine Durchmesserdifferenz in der Größenordnung von 0,3 mm auf. Dieses Führungsspiel führt zu einem Nacheilen des Kopplerdruckes gegenüber dem Systemdruck psys um etwa 100 µs. Aufgrund des Führungsspiels, welches sich aus der Durchmesserdifferenz in der Größenordnung von 0,3 mm ergibt, läuft während der Hubbewegung des Ventilkolbens 24 eine Kraftstoffmenge nach. Da die Kopplerhülse 30 nach jeder Einspritzung von der Stirnfläche 20 des Düsenkörpers 18 abhebt, findet die Kopplerhülse 30 nach jeder Einspritzung eine geringfügig andere Lage, wobei sich die Form des Führungsspaltes von Einspritzvorgang zu Einspritzvorgang ändert. Die in das Kopplervolumen nachströmende Kraftstoffmenge beeinflusst die Schließbewegung und den Schließzeitpunkt des bevorzugt nadelförmig ausgebildeten Einspritzventilgliedes 12, was zu Hub/Hub-Streuungen führt, die deutlich größer sind im Vergleich zu herkömmlichen Injektoren. Bei diesen herkömmlichen leckagebehafteten Kraftstoffinjektoren ist der Ventilkolben von unter Rücklaufdruck (Niederdruck) stehendem Kraftstoff umgeben. Dadurch kommt es zu einer kontinuierlichen Leckage aus dem Steuerraum entlang der Ventilkolbenführung einerseits und aus dem Hochdruckraum entlang des Einspritzventilgliedes entlang der Führung des Einspritzventilgliedes in das den Ventilkolben umgebende Volumen.The in FIG. 1 shown fuel injector 10 has between the inner diameter of the coupler sleeve 30 and the outer diameter of the injection valve member 12 has a diameter difference in the order of 0.3 mm. This guide clearance leads to a lag of the coupler pressure with respect to the system pressure p sys by about 100 μs. Due to the guide clearance, which results from the difference in diameter in the order of 0.3 mm, runs during the lifting movement of the valve piston 24, a fuel quantity after. Since the coupler sleeve 30 lifts off after each injection of the end face 20 of the nozzle body 18, the coupler sleeve 30 is found after each injection a slightly different position, wherein the shape of the guide gap changes from injection to injection process. The amount of fuel flowing into the coupler volume influences the closing movement and the closing time of the preferably needle-shaped injection valve member 12, which leads to lift / stroke spreads that are significantly greater compared to conventional injectors. In these conventional leaking fuel injectors, the valve piston is surrounded by fuel at low pressure (low pressure). This results in a continuous leakage from the control chamber along the valve piston guide on the one hand and from the high-pressure chamber along the injection valve member along the guide of the injection valve member in the surrounding the valve piston volume.

Im Unterschied dazu wird bei leckagefreien Injektoren das den Ventilkolben umgebende Volumen an den Hochdruckbereich angeschlossen. Dadurch unterbleibt die Leckage mangels eines Druckgefälles an den Führungen der relativ zueinander beweglichen Bauteile.In contrast, with leakage-free injectors, the volume surrounding the valve piston is connected to the high pressure area. As a result, the leakage is omitted due to the lack of a pressure gradient on the guides of the relatively movable components.

Der Darstellung gemäß Figur 2 ist ein Schnitt durch einen erfindungsgemäß vorgeschlagenen Koppler zu entnehmen. Aus Figur 2 geht hervor, dass der Kraftstoffinjektor 10 das nadelförmig ausgebildete Einspritzventilglied 12 umfasst, welches in der Bohrung 14 des Düsenkörpers 18 geführt ist. Im Hohlraum 16 des Kraftstoffinjektors 10 herrscht Systemdruck psys. An die Stirnseite 20 des Düsenkörpers 18 ist die Kopplerhülse 30 angestellt. Deren erste Stirnseite ist durch Bezugszeichen 32 und deren zweite Stirnseite durch Bezugszeichen 34 gekennzeichnet. Im Unterschied zur in Figur 1 dargestellten Kopplerhülse 30 weist die am erfindungsgemäß vorgeschlagenen Kraftstoffinjektor 10 eingesetzte Kopplerhülse 30 einen im Wesentlichen rechteckförmigen Querschnitt auf. Die Achse des bevorzugt nadelförmig ausgebildeten Einspritzventilgliedes 12 ist durch Bezugszeichen 22 bezeichnet. An der zweiten Stirnseite 34 der einen im Wesentlichen rechteckförmigen Querschnitt aufweisenden Kopplerhülse 30 befindet sich die Beißkante 36. Die Kopplerhülse 30 ist aufgrund der Wirkung einer Anstellkraft 50 an die Stirnseite 20 des Düsenkörpers 18 angestellt. Aus der Darstellung gemäß Figur 2 geht überdies hervor, dass ein Führungsspiel 40 zwischen dem Innendurchmesser 46 der Kopplerhülse 30 und dem Außendurchmesser des Ventilkolbens 24 ≤ 5 µm beträgt. Der Ventilkolben 24 weist in dem Bereich, d. h. seiner Führungslänge 58, in dem dieser in der Kopplerhülse 30 geführt ist, den Durchmesser 46 auf unter Berücksichtigung des Führungsspieles 40 von ≤ 5 µm auf die Kopplerhülse 30. Am Ventilkolben 24 des Kopplers ist ein Übergangsbereich 42 angedeutet, innerhalb dessen der Durchmesser des Ventilkolbens 24 in einen Durchmesser übergeht, der dem Durchmesser der im Düsenkörper 18 ausgebildeten Bohrung 14 entspricht und der im Wesentlichen dem Außendurchmesser 44 des Einspritzventilgliedes 12 entspricht. Aus der Darstellung gemäß Figur 2 geht hervor, dass in dem dargestellten Stadium der Hubphase des bevorzugt nadelförmig ausgebildeten Einspritzventilgliedes 12 und des Ventilkolbens 24 des Kopplers die Stirnseite 26 des Ventilkolbens 24 an einer Stirnseite 28 des bevorzugt nadelförmig ausgebildeten Einspritzventilgliedes 12 anliegt.The representation according to FIG. 2 is a section through a proposed inventions coupler. Out FIG. 2 It can be seen that the fuel injector 10 the needle-shaped injection valve member 12 includes, which is guided in the bore 14 of the nozzle body 18. In the cavity 16 of the fuel injector 10 system pressure p sys prevails. At the end face 20 of the nozzle body 18, the coupler sleeve 30 is employed. Their first end face is indicated by reference numeral 32 and the second end face by reference numeral 34. Unlike in FIG. 1 Coupler sleeve 30 shown has the coupler sleeve 30 used in accordance with the invention proposed fuel injector 10 has a substantially rectangular cross-section. The axis of the preferably needle-shaped injection valve member 12 is designated by reference numeral 22. The biting edge 36 is located on the second end face 34 of the coupler sleeve 30, which has a substantially rectangular cross-section. The coupler sleeve 30 is set against the end face 20 of the nozzle body 18 due to the effect of an adjusting force 50. From the illustration according to FIG. 2 moreover, it is apparent that a guide play 40 between the inner diameter 46 of the coupler sleeve 30 and the outer diameter of the valve piston 24 is ≦ 5 μm. The valve piston 24 has in the region, ie its guide length 58, in which this is guided in the coupler sleeve 30, the diameter 46, taking into account the guide clearance 40 of ≤ 5 microns on the coupler sleeve 30. At the valve piston 24 of the coupler is a transition region 42nd indicated within which the diameter of the valve piston 24 merges into a diameter which corresponds to the diameter of the nozzle body 18 formed in the bore 14 and which corresponds substantially to the outer diameter 44 of the injection valve member 12. From the illustration according to FIG. 2 shows that in the illustrated stage of the lifting phase of the preferably needle-shaped injection valve member 12 and the valve piston 24 of the coupler, the end face 26 of the valve piston 24 abuts an end face 28 of the preferably needle-shaped injection valve member 12.

Zwischen der Kopplerhülse 30, dem Außenumfang des Ventilkolbens 24 und der Stirnseite 20 des Düsenkörpers 18 ist ein Kopplerraum 54 ausgebildet, der ein Kopplervolumen aufweist, das in der Größenordnung von ≤ 40 mm3 liegt. Bei einem minimalen Führungsspiel 40 von ≤ 5 µm zwischen dem Innendurchmesser 46 der Kopplerhülse 30 und dem Außendurchmesser des Ventilkolbens 24 strömt am Hohlraum 16, in dem Systemdruck psys herrscht, eine vernachlässigbare Menge von unter Systemdruck psys stehendem Kraftstoff in den Kopplerraum 54 nach. Da der in den Kopplerraum 54 nachströmende Volumenstrom proportional zum Druckunterschied über die Führungslänge 58 jedoch umgekehrt proportional zur dritten Potenz des Führungsspieles 40 ist, ist die Verringerung des Führungsspieles 40 auf Werte unterhalb 5 µm zur Reduktion des nachströmenden Volumenstroms äußerst wirkungsvoll. Die Bohrung 14, in welcher ein Teil des Ventilkolbens 24 des Kopplers sowie das bevorzugt nadelförmig ausgebildete Einspritzventilglied 12 im Düsenkörper 18 geführt sind, weist an der Stirnseite 20 eine Fase 52 auf. An der Stirnseite 26 des Ventilkolbens 24 des Kopplers kann ebenfalls eine Fase 56 ausgebildet sein. Bevorzugt werden die Stirnseiten 26 und 28 vom Ventilkolben 24 beziehungsweise bevorzugt nadelförmig ausgebildeten Einspritzventilglied 12 plan ausgeführt. Der in der Darstellung gemäß Figur 2 dargestellte Kraftstoffinjektor 10 weist einerseits einen Durchmesserunterschied zwischen dem Innendurchmesser 46 der Kopplerhülse 30 und dem Außendurchmesser 44 des bevorzugt nadelförmig ausgebildeten Einspritzventilgliedes 12 zwischen 0,2 mm und 0 mm auf. Aufgrund dieses geringen verbleibenden Durchmesserunterschiedes wird der Druckabfall innerhalb des Kopplers während der Hubbewegung des bevorzugt nadelförmig ausgebildeten Einspritzventilgliedes 12 reduziert. Beträgt der Durchmesserunterschied zwischen dem Innendurchmesser 46 der Kopplerhülse 30 und dem Außendurchmesser 44 des bevorzugt nadelförmig ausgebildeten Einspritzventilgliedes 12 0 mm, entsteht ein Druckunterschied Δp nur noch während des Abhebens des bevorzugt nadelförmig ausgebildeten Einspritzventilgliedes 12 aus seinem Sitz und verschwindet wieder, sobald das bevorzugt nadelförmig ausgebildete Einspritzventilglied den Sitzdrosselbereich verlassen hat. Das Führungsspiel 50 zwischen der Kopplerhülse 30 und dem Ventilkolben 24 ist auf Werte ≤ 5 µm reduziert, so dass der über das reduzierte Führungsspiel 50 in den Kopplerraum 54 nachströmende Volumenstrom wirksam reduziert ist. Des Weiteren ist - wie in Figur 2 dargestellt - die Führungslänge 58, innerhalb der der Ventilkolben 24 des Kopplers in der Kopplerhülse 30 geführt ist, im Vergleich zur in Figur 1 dargestellten Führungslänge erheblich verlängert. Um ein möglichst verzögerungsfreies Nacheilen des bevorzugt nadelförmig ausgebildeten Einspritzventilgliedes 12 gegenüber dem Ventilkolben 24 zu erreichen, wird das Kraftstoffvolumen innerhalb der Kopplerhülse 30 im geschlossenen Zustand des Kraftstoffinjektors auf Werte ≤ 40 mm3 begrenzt.Between the coupler sleeve 30, the outer circumference of the valve piston 24 and the end face 20 of the nozzle body 18, a coupler space 54 is formed, which has a coupler volume which is of the order of ≦ 40 mm 3 . With a minimum guide clearance 40 of ≦ 5 μm between the inner diameter 46 of the coupler sleeve 30 and the outer diameter of the valve piston 24, a negligible amount of fuel under system pressure p sys flows into the coupler space 54 at the cavity 16 in the system pressure p sys . Since the volumetric flow flowing into the coupler space 54 is proportional to the pressure difference over the guide length 58 inversely proportional to the cube of the guide play 40, the reduction of the guide play 40 to values below 5 μm is extremely effective for reducing the inflowing volume flow. The bore 14, in which a part of the valve piston 24 of the coupler and the preferably needle-shaped injection valve member 12 in Nozzle body 18 are guided, has a chamfer 52 on the end face 20. On the end face 26 of the valve piston 24 of the coupler also a bevel 56 may be formed. Preferably, the end faces 26 and 28 of the valve piston 24 or preferably needle-shaped injection valve member 12 executed plan. In the illustration according to FIG. 2 shown Kraftstoffinjektor 10 has on the one hand a difference in diameter between the inner diameter 46 of the coupler sleeve 30 and the outer diameter 44 of the preferably needle-shaped injection valve member 12 between 0.2 mm and 0 mm. Because of this small remaining difference in diameter, the pressure drop within the coupler during the lifting movement of the preferably needle-shaped injection valve member 12 is reduced. If the difference in diameter between the inner diameter 46 of the coupler sleeve 30 and the outer diameter 44 of the preferably needle-shaped injection valve member 12 0 mm, creates a pressure difference Δp only during the lifting of the preferably needle-shaped injection valve member 12 from its seat and disappears again as soon as the preferably needle-shaped Injector valve member has left the seat throttle area. The guide clearance 50 between the coupler sleeve 30 and the valve piston 24 is reduced to values ≦ 5 μm, so that the volume flow flowing in via the reduced guide clearance 50 into the coupler space 54 is effectively reduced. Furthermore - as in FIG. 2 shown - the guide length 58, within which the valve piston 24 of the coupler is guided in the coupler sleeve 30, in comparison to in FIG. 1 shown guide length considerably extended. In order to achieve a lag-free as possible lagging the preferably needle-shaped injection valve member 12 relative to the valve piston 24, the fuel volume within the coupler sleeve 30 in the closed state of the fuel injector to values ≤ 40 mm 3 is limited.

Claims (9)

  1. Fuel injector (10) having a coupler (24, 30) for transmitting the stroke movement of an actuator to an injection valve member (12) which is in particular of needle-shaped design and which is guided in a nozzle body (18), with the coupler (24, 30) comprising a valve piston (24) and a coupler sleeve (30), with the injection valve member (12) having an outer diameter (44) and with the coupler sleeve (30) having an inner diameter (46), with the valve piston (24) being guided in the inner diameter (46) of the coupler sleeve (30), and with the inner diameter (46) of the coupler sleeve (30) being greater than the outer diameter (44) of the injection valve member (12), characterized in that the difference between the inner diameter (46) of the coupler sleeve (30) and the outer diameter (44) of the injection valve member (12) is at most 0.2 mm, and a transition region (42) is formed on the valve piston (24) of the coupler, within which transition region (42) the diameter of the valve piston (24) changes to a diameter corresponding to the diameter of a bore (14) which is formed in the nozzle body (18) and in which the injection valve member (12) is guided with the outer diameter (44).
  2. Fuel injector (10) according to Claim 1, characterized in that a coupler chamber (54) is formed between the valve piston (24), the coupler sleeve (30) and the injection valve member (12), and in that the coupler volume of the coupler chamber (54) amounts to at most 40 mm3.
  3. Fuel injector (10) according to Claim 1 or 2, characterized in that a guide play (40) between the coupler sleeve (30) and the valve piston (24) amounts to at most 5 µm.
  4. Fuel injector (10) according to one of the preceding claims, characterized in that a guide length (58) within which the valve piston (24) and the coupler sleeve (30) are guided amounts to at least 5 mm.
  5. Fuel injector (10) according to one of the preceding claims, characterized in that the bore (14) has a bevel (52) in the region of an end side (20) of the nozzle body (18).
  6. Fuel injector (10) according to one of the preceding claims, characterized in that the coupler sleeve (30) is loaded with a preload force (50) against an end side (20) of the nozzle body (18).
  7. Fuel injector (10) according to one of the preceding claims, characterized in that the coupler sleeve (30) has a biting edge (36).
  8. Fuel injector (10) according to one of the preceding claims, characterized in that the valve piston (24) has a bevel (56) on its end side (26) facing towards the injection valve member (12).
  9. Fuel injector (10) according to one of the preceding claims, characterized in that the coupler sleeve (30) has a substantially rectangular cross section parallel to its axis of symmetry.
EP07858229A 2007-01-16 2007-12-28 Fuel injector comprising a coupler Active EP2126333B1 (en)

Applications Claiming Priority (2)

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DE102007002282A DE102007002282A1 (en) 2007-01-16 2007-01-16 Fuel injector with coupler
PCT/EP2007/064641 WO2008086941A1 (en) 2007-01-16 2007-12-28 Fuel injector comprising a coupler

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EP2126333A1 EP2126333A1 (en) 2009-12-02
EP2126333B1 true EP2126333B1 (en) 2010-09-29

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US (1) US7992810B2 (en)
EP (1) EP2126333B1 (en)
JP (1) JP5002023B2 (en)
CN (1) CN101583790A (en)
AT (1) ATE483106T1 (en)
BR (1) BRPI0718797B1 (en)
DE (2) DE102007002282A1 (en)
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WO (1) WO2008086941A1 (en)

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EP3499213B1 (en) * 2017-12-15 2021-09-15 Microjet Technology Co., Ltd. Particulate matter measuring device
CN114135430B (en) * 2021-12-08 2023-01-06 一汽解放汽车有限公司 Fuel injection valve

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3788406T2 (en) * 1986-09-25 1994-04-14 Ganser Hydromag Zuerich Electronically controlled injection system.
DE4026721A1 (en) * 1990-08-24 1992-02-27 Bosch Gmbh Robert INJECTION VALVE AND METHOD FOR PRODUCING AN INJECTION VALVE
DE19500706C2 (en) * 1995-01-12 2003-09-25 Bosch Gmbh Robert Metering valve for dosing liquids or gases
DE19650865A1 (en) 1996-12-07 1998-06-10 Bosch Gmbh Robert magnetic valve
DE19946827C1 (en) * 1999-09-30 2001-06-21 Bosch Gmbh Robert Valve for controlling liquids
DE10145620B4 (en) * 2001-09-15 2006-03-02 Robert Bosch Gmbh Valve for controlling fluids
DE102004035280A1 (en) 2004-07-21 2006-03-16 Robert Bosch Gmbh Fuel injector with direct multi-stage injection valve element control
DE102005007543A1 (en) 2005-02-18 2006-08-24 Robert Bosch Gmbh Fuel injector with direct needle control for an internal combustion engine
RU2280781C1 (en) * 2005-03-05 2006-07-27 Федеральное государственное образовательное учреждение высшего профессионального образования Воронежский государственный аграрный университет им. К.Д. Глинки Electrohydraulic nozzle for diesel engine

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JP5002023B2 (en) 2012-08-15
CN101583790A (en) 2009-11-18
DE102007002282A1 (en) 2008-07-17
WO2008086941A1 (en) 2008-07-24
DE502007005235D1 (en) 2010-11-11
RU2009131122A (en) 2011-02-27
JP2010515855A (en) 2010-05-13
BRPI0718797A2 (en) 2013-12-03
BRPI0718797B1 (en) 2018-08-07
US7992810B2 (en) 2011-08-09
RU2452867C2 (en) 2012-06-10
US20100090032A1 (en) 2010-04-15
ATE483106T1 (en) 2010-10-15
EP2126333A1 (en) 2009-12-02

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