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EP1318294B1 - Injector, especially for common rail injection systems of diesel engines - Google Patents

Injector, especially for common rail injection systems of diesel engines Download PDF

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Publication number
EP1318294B1
EP1318294B1 EP02023349A EP02023349A EP1318294B1 EP 1318294 B1 EP1318294 B1 EP 1318294B1 EP 02023349 A EP02023349 A EP 02023349A EP 02023349 A EP02023349 A EP 02023349A EP 1318294 B1 EP1318294 B1 EP 1318294B1
Authority
EP
European Patent Office
Prior art keywords
control piston
restrictor
throttle
upper side
outflow restrictor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP02023349A
Other languages
German (de)
French (fr)
Other versions
EP1318294A1 (en
Inventor
Hermann Koch-Groeber
Uemit Canlioglu
Thilo Klam
Andreas Gaudl
Stefan Schuster
Christoffer Uhr
Andreas Rettich
Wolfgang Fleiner
Markus Rueckle
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
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Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP1318294A1 publication Critical patent/EP1318294A1/en
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Publication of EP1318294B1 publication Critical patent/EP1318294B1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M47/00—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
    • F02M47/02—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure of accumulator-injector type, i.e. having fuel pressure of accumulator tending to open, and fuel pressure in other chamber tending to close, injection valves and having means for periodically releasing that closing pressure
    • F02M47/027—Electrically actuated valves draining the chamber to release the closing pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/28—Details of throttles in fuel-injection apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/30—Fuel-injection apparatus having mechanical parts, the movement of which is damped
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/30—Fuel-injection apparatus having mechanical parts, the movement of which is damped
    • F02M2200/304—Fuel-injection apparatus having mechanical parts, the movement of which is damped using hydraulic 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
    • F02M2547/00—Special features for fuel-injection valves actuated by fluid pressure
    • F02M2547/003—Valve inserts containing control chamber and valve piston
    • 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
    • F02M2547/008—Means for influencing the flow rate out of or into a control chamber, e.g. depending on the position of the needle

Definitions

  • the invention relates to an injector according to the preamble of independent claim 1.
  • the opening required for the injection of the nozzle needle is realized by a servo valve.
  • the pressure in the control chamber is increased by feeding fuel to the control chamber via a so-called intake throttle (Z throttle) from an external pressure supply, eg, a Commen rail accumulator.
  • Z throttle intake throttle
  • the control piston is moved in the opposite direction. Based on the position of the control piston usually the A-throttle is centrally located and the Z-throttle on the outside.
  • a pressure arises in the control chamber, the lowering of which relative to the pressure of the pressure supply is essentially determined by the current flows of the A and Z throttles.
  • the control piston reaches a stop, which can be designed as a mechanical or hydraulic stop.
  • An injector with a mechanical control piston stop shows, for example, the EP 0 548 916 ,
  • the invention is based on this EP 0 548 916 A1 ,
  • This injector has a nozzle needle and a control piston for actuating the nozzle needle.
  • the flow from the inlet throttle to the outlet throttle can be additionally throttled at a narrowest cross section, which is formed by bypass bores.
  • the control piston is conically formed on its upper side facing the drain throttle and the counterpart cooperating with the control piston with the drain throttle is conical in the same sense as the upper side of the control piston, but with a different cone angle.
  • An injector with a hydraulic control piston stop is through the EP 0 661 442 known. This is the state of the art from which the present invention is based.
  • the mode of action of a hydraulic stop is such that the control piston, due to its changed position, additionally throttles the current flow from the Z throttle to the A throttle. This results in an increased pressure before the additional throttle at the narrowest cross section.
  • the narrowest cross-section is commonly referred to as "E-choke.”
  • the increased pressure acts on a large portion of the surface of the control piston with a force that opposes an opening of the valve piston, the control piston occupies such a position and thus determines the opening of the E-throttle. Throttle so that the two pressure forces with the other forces on the control piston bring it into an equilibrium position.
  • the well-known hydraulic control piston stop after EP 0 661 442 has the disadvantage that periodic movements of the control piston take place about the position of the hydraulic stop, which lead to oscillations of the entire system of the hydraulic stop, which can be both self-excited as well as foreign-excited. Because of the vibrations the hydraulic stop also vibrates the nozzle needle and thus the injection rate. The oscillations are expressed as a wave-shaped course of the injection quantity of the injector as a function of the actuation time of the actuator.
  • the object of the invention is to minimize the amplitudes of the described vibrations in the system of hydraulic stop so that they no longer adversely affect the injection process and thus can be considered negligible.
  • the core of the invention is thus the design of the narrowest cross-section (E-throttle) by a cone on the top of the control piston and the execution of the geometry in the counterpart, such that - with centric to the control piston lying A-throttle and external Z-throttle - the E-choke results on the smallest possible diameter.
  • the counterpart in this case has a larger cone angle than the control piston.
  • a throttle Drain throttle
  • a control piston 14 Coaxially with the A-throttle 11 is in the valve housing 10, a control piston 14 in the direction of arrow 15, i. axially, movably arranged.
  • the A-throttle 11 facing (in the drawing upper) remote end 16 of the control piston 14 is frusto-conical and cooperates with the conical extension 12 of the A-throttle 11 together. This results in a narrowest flow cross-section from the control chamber 13 to the A-throttle 11, which is quantified with 17 and should be referred to as "E-throttle".
  • the control chamber 13 is replaced by a laterally opening bore 18 of relatively small diameter, which with a suitable pressure supply, e.g. a pressure accumulator (so-called common rail) is connected, fuel supplied.
  • a suitable pressure supply e.g. a pressure accumulator (so-called common rail) is connected, fuel supplied.
  • the bore 18 is referred to as so-called.
  • Inlet throttle Z-throttle It is arranged in the embodiment shown with respect to the A-throttle 11 and the control piston 14 outboard.
  • the conical part 16 of the control piston 14 forms a hydraulic stop, which cooperates with the conical counterpart 12 of the A-throttle 11 as a counter-stop.
  • the cone angle of the counterpart, ⁇ counterpart is 60 °. (However, this value is only to be regarded as exemplary.) In principle, a conical angle of 120 ° would also be conceivable for the counterpart.)
  • the drawing makes it clear that the cone angle of the control piston 14, ⁇ control piston, a little smaller than ⁇ counterpart.
  • the resulting from the drawing geometric relationships results - advantageously - a very small slope of the cross section of the E-throttle 17 as a function of the stroke of the control piston 14.
  • the apparent from the drawing and described above arrangement operates as follows.

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

Description

Stand der TechnikState of the art

Die Erfindung bezieht sich auf einen Injektor nach dem Oberbegriff des unabhängigen Patentanspruchs 1.The invention relates to an injector according to the preamble of independent claim 1.

Bei Injektoren, insbesondere solchen für Common-Rail-Einspritzsysteme von Dieselmotoren, wird die zur Einspritzung erforderliche Öffnung der Düsennadel durch ein Servoventil realisiert. Ein Aktor, z. B. ein Magnetventil oder Piezoelement, öffnet ein Ventil und senkt über eine sog. Ablauf-Drossel (A-Drossel) den Druck in einem Steuerraum. Dieser ist begrenzt durch den Steuerkolben, welcher auf die Düsennadel einwirkt. Der abgesenkte Druck im Steuerraum auf der Wirkfläche des Steuerkolbens verändert das Kräftegleichgewicht am Steuerkolben und setzt ihn bei Unterschreiten eines Schwellenwertes des Druckes in Bewegung. Wird das Ventil durch den Aktor geschlossen, so erfolgt im Steuerraum eine Anhebung des Druckes, indem dem Steuerraum über eine sog. Zulauf-Drossel (Z-Drossel) aus einer externen Druckversorgung, z.B. einem Commen-Rail-Speicher, Kraftstoff zugeführt wird. Infolge der Druckerhöhung wird der Steuerkolben in entgegengesetzte Richtung bewegt. Bezogen auf die Lage des Steuerkolbens ist üblicherweise die A-Drossel zentrisch und die Z-Drossel außenliegend angeordnet.In injectors, in particular those for common-rail injection systems of diesel engines, the opening required for the injection of the nozzle needle is realized by a servo valve. An actor, z. B. a solenoid valve or piezo element, opens a valve and lowers a so-called. Drain throttle (A-throttle) the pressure in a control room. This is limited by the control piston, which acts on the nozzle needle. The lowered pressure in the control chamber on the effective surface of the control piston changes the balance of forces on the control piston and sets it when falling below a threshold value of the pressure in motion. If the valve is closed by the actuator, the pressure in the control chamber is increased by feeding fuel to the control chamber via a so-called intake throttle (Z throttle) from an external pressure supply, eg, a Commen rail accumulator. As a result of the pressure increase, the control piston is moved in the opposite direction. Based on the position of the control piston usually the A-throttle is centrally located and the Z-throttle on the outside.

Im geöffneten Zustand des Ventils stellt sich im Steuerraum ein Druck ein, dessen Absenkung gegenüber dem Druck der Druckversorgung im Wesentlichen von den aktuellen Durchflüssen von A- und Z-Drossel bestimmt wird. Bei ausreichend langzeitiger Öffnung des Ventils erreicht der Steuerkolben einen Anschlag, der als mechanischer oder hydraulischer Anschlag ausgebildet sein kann. Einen Injektor mit einem mechanischen Steuerkolben-Anschlag (Festanschlag) zeigt beispielsweise die EP 0 548 916 .In the opened state of the valve, a pressure arises in the control chamber, the lowering of which relative to the pressure of the pressure supply is essentially determined by the current flows of the A and Z throttles. With sufficiently long-term opening of the valve, the control piston reaches a stop, which can be designed as a mechanical or hydraulic stop. An injector with a mechanical control piston stop (fixed stop) shows, for example, the EP 0 548 916 ,

Die Erfindung geht aus von dieser EP 0 548 916 A1 . Durch diese ist ein Injektor, insbesondere für Common-Rail-Einspritzsysteme von Dieselmotoren, bekannt. Dieser Injektor weist eine Düsennadel und einen Steuerkolben zur Betätigung der Düsennadel auf. Es ist ein den Steuerkolben betätigendes, durch einen Aktor, über eine Ablauf-Drossel und eine Zulauf-Drossel angesteuertes Ventil vorhanden. Für den Steuerkolben ist ein mechanischer Anschlag vorhanden. Wenn der Steuerkolben am Anschlag anliegt, so wird durch diesen der Durchfluss von der Zulauf-Drossel zur Ablauf-Drossel vollständig oder teilweise verschlossen. Der Durchfluss von der Zulauf-Drossel zur Ablauf-Drossel ist an einem engsten Querschnitt zusätzlich drosselbar, der durch Bypassbohrungen gebildet ist. Der Steuerkolben ist an seiner der Ablauf-Drossel zugewandten Oberseite konisch ausgebildet und das mit dem Steuerkolben zusammenwirkende Gegenstück mit der Ablauf-Drossel ist im gleichen Sinne wie die Oberseite des Steuerkolbens, jedoch mit differierendem Konuswinkel konisch ausgebildet.The invention is based on this EP 0 548 916 A1 , This is an injector, especially for common rail injection systems of diesel engines, known. This injector has a nozzle needle and a control piston for actuating the nozzle needle. There is a control piston actuating, actuated by an actuator, via a drain throttle and an inlet throttle valve available. There is a mechanical stop for the control piston. If the control piston abuts against the stop, then the flow from the inlet throttle to the outlet throttle is completely or partially closed by this. The flow from the inlet throttle to the outlet throttle can be additionally throttled at a narrowest cross section, which is formed by bypass bores. The control piston is conically formed on its upper side facing the drain throttle and the counterpart cooperating with the control piston with the drain throttle is conical in the same sense as the upper side of the control piston, but with a different cone angle.

Auch durch die EP 0 916 842 A1 ist ein Injektor bekannt, bei dem der Steuerkolben und das mit diesem zusammenwirkende Gegenstück mit der Ablauf-Drossel konisch ausgebildet sind, jedoch ein mechanischer Anschlag für den Steuerkolben vorhanden ist.Also by the EP 0 916 842 A1 an injector is known in which the control piston and cooperating with this counterpart with the drain throttle are conical, but a mechanical stop for the control piston is present.

Ein Injektor mit einem hydraulischen Steuerkolben-Anschlag ist durch die EP 0 661 442 bekannt geworden. Hierbei handelt es sich um den Stand der Technik, von dem die vorliegende Erfindung ausgeht. Die Wirkungsweise eines hydraulischen Anschlags ist dergestalt, dass der Steuerkolben durch seine veränderte Position den aktuellen Durchfluss von der Z--Drossel zur A-Drossel zusätzlich drosselt. Es ergibt sich dadurch ein erhöhter Druck vor der zusätzlichen Drossel am engsten Querschnitt. Der engste Querschnitt wird üblicherweise als E-Drossel" bezeichnet. Der erhöhte Druck wirkt auf einen großen Teil der Fläche des Steuerkolbens mit einer Kraft, die einer Öffnung des Ventilkolbens entgegenwirkt. Der Steuerkolben nimmt eine solche Position ein und bestimmt damit die Öffnung der E-Drossel so, dass die beiden Druckkräfte mit den weiteren Kräften am Steuerkolben diesen in eine Gleichgewichtsposition bringen.An injector with a hydraulic control piston stop is through the EP 0 661 442 known. This is the state of the art from which the present invention is based. The mode of action of a hydraulic stop is such that the control piston, due to its changed position, additionally throttles the current flow from the Z throttle to the A throttle. This results in an increased pressure before the additional throttle at the narrowest cross section. The narrowest cross-section is commonly referred to as "E-choke." The increased pressure acts on a large portion of the surface of the control piston with a force that opposes an opening of the valve piston, the control piston occupies such a position and thus determines the opening of the E-throttle. Throttle so that the two pressure forces with the other forces on the control piston bring it into an equilibrium position.

Der bekannte hydraulische Steuerkolben-Anschlag nach EP 0 661 442 hat den Nachteil, dass periodische Bewegungen des Steuerkolbens um die Position des hydraulischen Anschlags erfolgen, die zu Schwingungen des gesamten Systems des hydraulischen Anschlags führen, welche sowohl eigenerregt als auch fremderregt sein können. Aufgrund der Schwingungen des hydraulischen Anschlags schwingt auch die Düsennadel und damit die Einspritzrate. Die Schwingungen äußern sich als wellenförmiger Verlauf der Einspritzmenge des Injektors als Funktion der Ansteuerzeit des Aktors.The well-known hydraulic control piston stop after EP 0 661 442 has the disadvantage that periodic movements of the control piston take place about the position of the hydraulic stop, which lead to oscillations of the entire system of the hydraulic stop, which can be both self-excited as well as foreign-excited. Because of the vibrations the hydraulic stop also vibrates the nozzle needle and thus the injection rate. The oscillations are expressed as a wave-shaped course of the injection quantity of the injector as a function of the actuation time of the actuator.

Man hat zwar bereits versucht, durch Minimierung des Steuerraum-Volumens die Schwingungsamplituden zu verringern. Neuere Entwicklungen haben indessen gezeigt, dass diese Maßnahme nicht ausreichend ist und ihr konstruktive Grenzen gesetzt sind, z.B. dadurch, dass die relative Toleranz des Volumens sich bei Minimierung vergrößert, mit negativen Folgen für die Einspritzmengen-Toleranzen. Des Weiteren verstärkt sich die Neigung zu Schwingungen mit Erhöhung des Systemdrucks, was positiv für die Motorfunktion ist.It has already been attempted to reduce the vibration amplitudes by minimizing the control chamber volume. However, recent developments have shown that this measure is insufficient and has constructive limitations, e.g. in that the relative tolerance of the volume increases with minimization, with negative consequences for the injection quantity tolerances. Furthermore, the tendency for vibrations increases with increasing system pressure, which is positive for engine function.

Aufgabe der Erfindung ist es, die Amplituden der geschilderten Schwingungen im System des hydraulischen Anschlags so zu minimieren, dass sie sich auf den Einspritzvorgang nicht mehr nachteilig auswirken und damit als vernachlässigbar betrachtet werden können.The object of the invention is to minimize the amplitudes of the described vibrations in the system of hydraulic stop so that they no longer adversely affect the injection process and thus can be considered negligible.

Vorteile der ErfindungAdvantages of the invention

Gemäß der Erfindung wird die Aufgabe bei einem Injektor der eingangs bezeichneten Art durch die Merkmale des unabhängigen spruchs 1 gelöst.According to the invention, the object is achieved in an injector of the type described by the features of independent claim 1.

Durch die EP 0 548 916 ist es zwar an sich bekannt, den Steuerkolben mit einer konischen Oberseite zu versehen. Jedoch bezieht sich die genannte Druckschrift - im Gegensatz zur vorliegende Erfindung auf einen Festanschlag. Die aus der EP 0 548 916 bekannte Paarung zweier Konen (einerseits des Steuerkolbens, andererseits des Gegenstücks) dient nämlich einem von der Zielsetzung der vorliegenden Erfindung völlig abweichenden Zweck: Die Paarung der Konen hat lediglich die Aufgabe, den Durchmesser des Festanschlages zu definieren. Dieser Durchmesser muß erheblich kleiner sein als der Durchmesser des Steuerkolbens selbst, da andernfalls der Schließvorgang unbrauchbar verlangsamt wird.By the EP 0 548 916 Although it is known per se to provide the control piston with a conical top. However, the cited reference - in contrast to the present invention relates to a hard stop. The from the EP 0 548 916 Namely known pairing of two cones (on the one hand of the control piston, on the other hand, the counterpart) serves a purpose entirely different from the objective of the present invention: The mating of Konen has only the task to define the diameter of the fixed stop. This diameter must be considerably smaller than the diameter of the control piston itself, since otherwise the closing process is slowed useless.

Vorteilhafte Ausgestaltungen des Grundgedankens der Erfindung enthalten die abhängigen Ansprüche 2 - 5.Advantageous embodiments of the basic concept of the invention include the dependent claims 2-5.

Kern der Erfindung ist also die Ausgestaltung des engsten Querschnittes (E-Drossel) durch einen Konus auf der Oberseite des Steuerkolbens sowie die Ausführung der Geometrie im Gegenstück, derart, dass sich - bei zentrisch zum Steuerkolben liegender A-Drossel und aussenliegender Z-Drossel - die E-Drossel auf einem möglichst kleinen Durchmesser ergibt. Das Gegenstück weist in diesem Fall einen größeren Konuswinkel als der Steuerkolben auf.The core of the invention is thus the design of the narrowest cross-section (E-throttle) by a cone on the top of the control piston and the execution of the geometry in the counterpart, such that - with centric to the control piston lying A-throttle and external Z-throttle - the E-choke results on the smallest possible diameter. The counterpart in this case has a larger cone angle than the control piston.

Zeichnungdrawing

Die Erfindung ist in der Zeichnung anhand eines Ausführungsbeispiels veranschaulicht, das im Folgenden beschrieben wird. Die Zeichnung zeigt

  • im Vertikalschnitt und stark vergrößert - einen Ausschnitt eines Servoventils für Injektoren, mit einer Ausführungsform eines hydraulischen Anschlags.
The invention is illustrated in the drawing with reference to an embodiment which will be described below. The drawing shows
  • in vertical section and greatly enlarged - a section of a servo valve for injectors, with an embodiment of a hydraulic stop.

Beschreibung des AusführungsbeispielsDescription of the embodiment

Es bezeichnet 10 ein Ventilgehäuse mit einer Bohrung 11, die als sog. Ablauf-Drossel (A-Drossel) fungiert. Die A-Drossel 11 ist am unteren Ende - bei 12 - konisch erweitert ausgebildet und mündet dort in einen Steuerraum 13.It designates 10 a valve housing with a bore 11, which acts as a so-called. Drain throttle (A throttle). The A-throttle 11 is formed at the lower end - at 12 - flared and opens into a control room thirteenth

Koaxial zu der A-Drossel 11 ist im Ventilgehäuse 10 ein Steuerkolben 14 in Pfeilrichtung 15, d.h. axial, beweglich angeordnet. Das der A-Drossel 11 zugewandte (in der Zeichnung obere) abgesetzte Ende 16 des Steuerkolbens 14 ist kegelstumpfförmig ausgebildet und wirkt mit der konischen Erweiterung 12 der A-Drossel 11 zusammen. Hierbei ergibt sich ein engster Durchflussquerschnitt vom Steuerraum 13 zur A-Drossel 11, der mit 17 beziffert ist und als "E-Drossel" bezeichnet werden soll.Coaxially with the A-throttle 11 is in the valve housing 10, a control piston 14 in the direction of arrow 15, i. axially, movably arranged. The A-throttle 11 facing (in the drawing upper) remote end 16 of the control piston 14 is frusto-conical and cooperates with the conical extension 12 of the A-throttle 11 together. This results in a narrowest flow cross-section from the control chamber 13 to the A-throttle 11, which is quantified with 17 and should be referred to as "E-throttle".

Dem Steuerraum 13 wird durch eine seitlich einmündende Bohrung 18 vergleichsweise geringen Durchmessers, die mit einer geeigneten Druckversorgung, z.B. einem Druckspeicher (sog. Common-Rail), verbunden ist, Kraftstoff zugeführt. Die Bohrung 18 ist als sog. Zulauf-Drossel (Z-Drossel) bezeichnet. Sie ist bei dem gezeigten Ausführungsbeispiels in Hinsicht auf die A-Drossel 11 und den Steuerkolben 14 aussenliegend angeordnet.The control chamber 13 is replaced by a laterally opening bore 18 of relatively small diameter, which with a suitable pressure supply, e.g. a pressure accumulator (so-called common rail) is connected, fuel supplied. The bore 18 is referred to as so-called. Inlet throttle (Z-throttle). It is arranged in the embodiment shown with respect to the A-throttle 11 and the control piston 14 outboard.

Der konische Teil 16 des Steuerkolbens 14 bildet einen hydraulischen Anschlag, der mit dem konischen Gegenstück 12 der A-Drossel 11 als Gegenanschlag kooperiert. Bei dem dargestellten Ausführungsbeispiel beträgt der Konuswinkel des Gegenstücks, α Gegenstück 60°. (Dieser Wert ist jedoch nur als beispielhaft zu betrachten. Im Prinzip wäre für das Gegenstück auch ein Konuswinkel von 120° denkbar.) Die Zeichnung macht deutlich, dass der Konuswinkel des Steuerkolbens 14, α Steuerkolben, noch etwas kleiner bemessen ist als α Gegenstück. Durch die aus der Zeichnung hervorgehenden geometrischen Verhältnisse ergibt sich - vorteilhafterweise - eine sehr geringe Steigung des Querschnittes der E-Drossel 17 als Funktion des Hubes des Steuerkolbens 14. Die aus der Zeichnung ersichtliche und im Vorstehenden beschriebene Anordnung arbeitet wie folgt. In geöffnetem Zustand des Servoventils stellt sich im Steuerraum 13 ein Druck ein, der - bedingt durch die Drosselquerschnitte von A-Drossel 11 und Z-Drossel 18 - niedriger ist als der auf die (in der Zeichnung nicht gezeigte) Rückseite des Steuerkolbens 14 wirkende Druck der Druckversorgung (z.B. eines CR-Speichers). Infolge dieses Druckunterschiedes bewegt sich der Steuerkolben 14 in Pfeilrichtung 19. Bleibt das Servoventil genügend lange geöffnet, so erreicht der Steuerkolben 14 schließlich die in der Zeichnung dargestellte (obere) Anschlagstellung. Dass es sich hierbei um einen sog. hydraulischen Anschlag handelt, will besagen, dass der Steuerkolben 14 durch seine veränderte Position den aktuellen Durchfluss von der Z-Drossel 18 zur A-Drossel 11 (s. die Pfeile 20-23) zusätzlich drosselt. Dadurch ergibt sich ein erhöhter Druck vor der A-Drossel 11 am engsten Querschnitt (E-Drossel 17). Dieser erhöhte Druck wirkt auf einen großen Teil der Stirnfläche 24 des Steuerkolbens 14 mit einer Kraft, die einer Öffnungsbewegung des Ventilkolbens (nicht gezeigt) entgegenwirkt. Der Steuerkolben 14 nimmt somit eine Position ein, in der er die Öffnung der E-Drossel 17 so bestimmt, dass die beiden auf den Steuerkolben 14 wirkenden Druckkräfte zusammen mit den externen Kräften am Steuerkolben 14 im Gleichgewicht stehen.The conical part 16 of the control piston 14 forms a hydraulic stop, which cooperates with the conical counterpart 12 of the A-throttle 11 as a counter-stop. In the illustrated embodiment, the cone angle of the counterpart, α counterpart is 60 °. (However, this value is only to be regarded as exemplary.) In principle, a conical angle of 120 ° would also be conceivable for the counterpart.) The drawing makes it clear that the cone angle of the control piston 14, α control piston, a little smaller than α counterpart. The resulting from the drawing geometric relationships results - advantageously - a very small slope of the cross section of the E-throttle 17 as a function of the stroke of the control piston 14. The apparent from the drawing and described above arrangement operates as follows. In the open state of the servo valve is in the control chamber 13, a pressure which - due to the throttle cross-sections of the A-throttle 11 and Z-throttle 18 - is lower than the pressure acting on the (not shown in the drawing) back of the control piston 14 pressure the pressure supply (eg a CR memory). As a result of this pressure difference, the control piston 14 moves in the direction of arrow 19. If the servo valve remains open long enough, the control piston 14 finally reaches the (upper) stop position shown in the drawing. The fact that this is a so-called hydraulic stop means that the control piston 14 additionally throttles the current flow from the Z throttle 18 to the A throttle 11 (see arrows 20-23) due to its changed position. This results in an increased pressure before the A-throttle 11 at the narrowest cross-section (E-throttle 17). This increased pressure acts on a large part of the end face 24 of the control piston 14 with a force which counteracts an opening movement of the valve piston (not shown). The control piston 14 thus assumes a position in which it determines the opening of the E-throttle 17 so that the two pressure forces acting on the control piston 14 are in equilibrium together with the external forces on the control piston 14.

Claims (5)

  1. Injector, in particular for common rail injection systems of diesel engines, having a nozzle needle, having a control piston (14) for actuation of the nozzle needle, having a valve which actuates the control piston (14) and is activated by an actuator via an outflow restrictor (11) and a feed restrictor (18), and having a stop (16) for the control piston (14), it additionally being possible for the throughflow from the feed restrictor (18) to the outflow restrictor (11) to be throttled on a very narrow cross section, the control piston (14) being of at least partially conical configuration on its upper side (16) which faces the outflow restrictor (11), and the corresponding element to the outflow restrictor (11) which interacts with the control piston (14) being of conical configuration in the same direction as the upper side (16) of the control piston (14) but with a differing cone angle (α), characterized in that the control piston (14) has a recessed upper side (16) which is of conical configuration, in that the conical surface of the conically recessed upper side (16) of the control piston (14) interacts with the conical surface of the corresponding element to the outflow restrictor (11), in that the very narrow cross section (17) is formed between the conically configured, recessed upper side (16) of the control piston (14) and the corresponding element to the outflow restrictor (11), and in that an increased pressure is generated upstream of the outflow restrictor (11) as a result of the throttling action in the very narrow cross section (17), which increased pressure counteracts the reciprocating movement of the control piston (14) which is directed towards the corresponding element to the outflow restrictor (11), as a result of which a hydraulic stop (16) for the control piston (14) is formed.
  2. Injector according to Claim 1, characterized in that the cone angle (αcorresponding element) of the outflow restrictor (11) is greater than the cone angle (αcontrol piston) of the control piston (14).
  3. Injector according to one of the preceding claims, characterized in that the cone angles (α) of the control piston (14) and of the outflow restrictor (11) are acute angles.
  4. Injector according to Claim 3, characterized in that the cone angle (αcontrol piston) of the control piston (14) is smaller than or at most equal to 60°.
  5. Injector according to one of the preceding claims, characterized in that the conically configured, recessed upper side (16) of the control piston (14) is a truncated cone.
EP02023349A 2001-12-07 2002-10-18 Injector, especially for common rail injection systems of diesel engines Expired - Lifetime EP1318294B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE10160262 2001-12-07
DE10160262A DE10160262A1 (en) 2001-12-07 2001-12-07 Injector, in particular for common rail injection systems for diesel engines

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EP1318294A1 EP1318294A1 (en) 2003-06-11
EP1318294B1 true EP1318294B1 (en) 2007-08-15

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US (1) US6896198B2 (en)
EP (1) EP1318294B1 (en)
JP (1) JP2003193930A (en)
DE (2) DE10160262A1 (en)

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DE10334209A1 (en) * 2003-07-26 2005-02-10 Robert Bosch Gmbh Fuel injection device for an internal combustion engine
DE102004010759A1 (en) * 2004-03-05 2005-09-22 Robert Bosch Gmbh Common rail injector
EP2085604A1 (en) * 2008-02-04 2009-08-05 Robert Bosch GmbH Fuel injector
ATE546636T1 (en) * 2009-08-26 2012-03-15 Delphi Tech Holding Sarl FUEL INJECTOR
DE102010028046A1 (en) * 2010-04-21 2011-10-27 Robert Bosch Gmbh high pressure pump
EP2503138B1 (en) * 2011-03-24 2013-05-08 OMT Officine Meccaniche Torino S.p.A. Electrically-controlled fuel injector for large diesel engines
WO2014210148A1 (en) * 2013-06-26 2014-12-31 Cummins Inc. Fuel injector including features to reduce viscous heating in a control valve and a drain circuit

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EP0548916A1 (en) * 1991-12-24 1993-06-30 ELASIS SISTEMA RICERCA FIAT NEL MEZZOGIORNO Società Consortile per Azioni Electromagnetic fuel injection valve
EP0916842A1 (en) * 1997-11-18 1999-05-19 ELASIS SISTEMA RICERCA FIAT NEL MEZZOGIORNO Società Consortile per Azioni Device for controlling an internal combustion engine fuel injector

Also Published As

Publication number Publication date
DE10160262A1 (en) 2003-06-18
DE50210690D1 (en) 2007-09-27
JP2003193930A (en) 2003-07-09
EP1318294A1 (en) 2003-06-11
US6896198B2 (en) 2005-05-24
US20030106947A1 (en) 2003-06-12

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