EP1537327A1 - Injector, especially a common rail injector controlled by a servo valve, for injecting fuel into the combustion chambers of internal combustion engines - Google Patents

Injector, especially a common rail injector controlled by a servo valve, for injecting fuel into the combustion chambers of internal combustion engines

Info

Publication number
EP1537327A1
EP1537327A1 EP03794766A EP03794766A EP1537327A1 EP 1537327 A1 EP1537327 A1 EP 1537327A1 EP 03794766 A EP03794766 A EP 03794766A EP 03794766 A EP03794766 A EP 03794766A EP 1537327 A1 EP1537327 A1 EP 1537327A1
Authority
EP
European Patent Office
Prior art keywords
nozzle needle
nozzle
injector
face
needle
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.)
Withdrawn
Application number
EP03794766A
Other languages
German (de)
French (fr)
Inventor
Karl-Heinz Stahl
Wolfgang Stoecklein
Dietmar Schmieder
Olivier Kristen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP1537327A1 publication Critical patent/EP1537327A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M47/00—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
    • F02M47/02—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure of accumulator-injector type, i.e. having fuel pressure of accumulator tending to open, and fuel pressure in other chamber tending to close, injection valves and having means for periodically releasing that closing pressure
    • 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
    • F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
    • F02M61/18—Injection nozzles, e.g. having valve seats; Details of valve member seated ends, not otherwise provided for
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M47/00—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
    • F02M47/02—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure of accumulator-injector type, i.e. having fuel pressure of accumulator tending to open, and fuel pressure in other chamber tending to close, injection valves and having means for periodically releasing that closing pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • 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
    • 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
    • F02M61/20—Closing valves mechanically, e.g. arrangements of springs or weights or permanent magnets; Damping of valve lift
    • F02M61/205—Means specially adapted for varying the spring tension or assisting the spring force to close the injection-valve, e.g. with damping of valve lift
    • 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
    • F02M2200/50—Arrangements of springs for valves used in fuel injectors or fuel injection pumps
    • 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
    • F02M2547/001—Control chambers formed by movable sleeves
    • 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
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/0014—Valves characterised by the valve actuating means
    • F02M63/0015—Valves characterised by the valve actuating means electrical, e.g. using solenoid
    • F02M63/0026—Valves characterised by the valve actuating means electrical, e.g. using solenoid using piezoelectric or magnetostrictive actuators

Definitions

  • the invention relates to an injector for injecting fuel into combustion chambers of internal combustion engines, in particular to a sentoventil-controlled common rail injector, with a nozzle body, on the combustion chamber-side (free) end of which a nozzle outlet is formed, with a nozzle needle which is in a longitudinal recess of the nozzle body is arranged to be axially movable or actuatable, with a closing part which closes the rear end (facing away from the nozzle outlet) and (above) adjoins the nozzle body and forms an opening stop for the nozzle needle, here with the rear end (facing away from the nozzle outlet) End face of the nozzle needle cooperates and thus limits the opening stroke of the nozzle needle, and with a control chamber formed between the rear nozzle needle end face and the end part, which is in hydraulic connection with a pressure connection serving the fuel supply TEHT.
  • a CR injector of the aforementioned type has become known from DE 199 36 668 A1.
  • the rear end face of the nozzle needle which cooperates with the flat stop face of the end part, is also flat.
  • the required needle stroke is produced by appropriate grinding of the back face of the nozzle needle.
  • the needle stroke tolerance has to be as small as possible - because of the quantity scatter of the individual injectors - there are several disadvantages from the known concept of two flat stop surfaces. On the one hand, it has the disadvantage that - due to manufacturing tolerances in the manufacture of the nozzle needle on the one hand and the guide bore for the
  • Nozzle needle in the nozzle body on the other hand - slight lateral or tilting movements of the nozzle needle occur during the axial movement of the nozzle needle (so-called "forehead").
  • the needle stroke can change when the nozzle needle is rotated, thereby increasing the needle stroke tolerance Oblique division of the end part to the guide hole of the nozzle needle.
  • the object of the invention is to avoid the disadvantages described above, ie to create an injector that is characterized by a minimal nozzle needle stroke tolerance and a constant nozzle needle stroke, even when the nozzle needle is twisted, and by a comparatively small adjustment tolerance when grinding in the nozzle needle stroke distinguished.
  • the object is achieved in an injector of the type described in the introduction in that the rear end face of the nozzle needle and / or the stop face of the end part interacting therewith is designed such that in the open position of the nozzle needle there is a punctiform or essentially punctiform contact surface between the rear nozzle needle face and the stop surface of the end piece.
  • the nozzle needle should have a spherical, preferably spherical, rear end face.
  • the measures according to the invention result at the upper stop of the nozzle needle, i.e. in the open position thereof, an (almost) punctiform contact surface between the end part and the rear (upper) end face of the nozzle needle.
  • the radius of the rear end of the nozzle needle should be dimensioned where it comes into contact with the stop surface of the end part so that - taking into account that on the nozzle needle effective opening force - the permissible Hertz 'see pressure is not exceeded.
  • Fig. 1 shows an embodiment of a CR injector, in vertical longitudinal section, and
  • FIG. 2 shows the detail “A” from FIG. 1 in an enlarged manner compared to FIG. 1
  • nozzle needle 14 designates 10 as a whole a multi-offset nozzle body with a central longitudinal recess 11 which narrows at its lower end to form a nozzle outlet 12. Above the nozzle outlet 12, the longitudinal recess 11 forms a conical valve seat 13. In the longitudinal recess 11. a nozzle needle, numbered 14 overall, is arranged to be axially movable. A lower, tapered end 15 of the nozzle needle 14 is conical and interacts with the likewise conical valve seat 13.
  • valve body 10 Above the valve body 10 and seated sealingly on its upper end face 16, a disc-shaped end part 17 is arranged.
  • the end part 17 is adjoined at the top - likewise sealingly - by a servo valve body 18, in which a servo valve 19, for example a piezoelectrically operated one, is received.
  • Valve body 10, end part 17 and servo valve body 18 are enclosed by an injector housing 20 and fixed in the assignment shown in FIG. 1.
  • a high-pressure channel 21 is incorporated into the servo valve body 18, which - via a (not shown) high-pressure connection - is in hydraulic connection with a (also not shown) fuel high-pressure accumulator (so-called common rail) ,
  • the high-pressure duct 21 opens out - via an extension 22 - on the lower end face 23 of the servo valve body 18 and is there with two into it
  • End part 17 incorporated holes 24 and 25 hydraulically connected.
  • the high-pressure fuel passes through the first bore 24 - via an annular space 26 - into the longitudinal recess 11 of the nozzle body 10 and thus - with the valve 13, 15 open - to the nozzle outlet 12.
  • a special feature of the second bore 25 is that it narrows in steps to a throttle bore 27 (so-called inlet throttle). Via this inlet throttle 27, fuel reaches a control chamber 28 which extends between the upper end of the nozzle needle 14 and the lower end face of the end part 17, numbered 29.
  • the control chamber 28 reaches its maximum volume when the nozzle needle 14 is in the closed position shown in FIGS. 1 and 2, the conical end 15 of which is sealingly in contact with the valve seat 13. In this closed position, the nozzle needle 14 is held on the one hand by the liquid pressure prevailing in the control chamber 28 and on the other hand by a compression spring 30.
  • a further bore 35 is machined, which is on the one hand via bore 24 and annular space 26 - with the high-pressure duct 21 and on the other hand - via a throttle bore 36 (so-called discharge throttle) - with the servo valve 19 in hydraulic operative connection.
  • the rear (upper) end face of the nozzle needle 14, numbered 37 has a spherical curvature.
  • the spherical radius is shown in Fig. 1 and 2 are denoted by r kuge ⁇ .
  • the apex P (see FIG. 2) of the spherical surface 37 determines the upper stop of the nozzle needle 14, which interacts with the surface 29 of the end part 17 as a counter stop.
  • the nozzle needle stroke denoted by h DN in FIG. 2.
  • the nozzle needle 14 In its (upper) open position, the nozzle needle 14 thus comes to rest at point P with the surface 29 of the end part 17.
  • the avoidance of a (large) surface contact of the nozzle needle 14 on the stop face 29 of the end part 17 results in an - otherwise possible - "sticking" of the nozzle needle 14 in its (
  • the spherical / spherical nozzle needle end face 37 ensures that a sufficiently large control space 28 remains in the open position of the nozzle needle 14.
  • the spherical / spherical design of the nozzle needle end face 37 results in the resulting almost punctiform nozzle needle stop moreover the advantage that the nozzle needle stroke h DN always remains constant in the event of any rotation of the nozzle needle 14 or when it is inclined due to manufacturing tolerances.

Landscapes

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

Abstract

An injector, especially a common rail injector controlled by a servo valve, for injecting fuel into the combustion chambers of internal combustion engines, comprising a nozzle body (10) with a nozzle outlet (12) formed on the combustion-sided (free) end thereof, in addition to a nozzle needle (14) which is arranged in a longitudinal recess (11) of the valve body (10) such that it can be displaced or actuated axially. The injector also comprises a sealing part (17) which is adjacent to (above) the valve body and which seals the rear end (i.e. end facing away from the nozzle outlet (12)) of the longitudinal recess (11) and which forms an opening stop (29) for the nozzle needle (14), cooperating with the rear (i.e. end facing away from the nozzle outlet (12)) surface (37) of the valve needle (14) and defines the opening lift (hDN) of the nozzle needle (14). The injector further comprises a control chamber (28) which is formed between the rear nozzle surface (37) and the sealing part (17) and which is hydraulically connected to a pressure connection (21) used to supply fuel. One particular aspect of the injector is that the rear surface (37) of the nozzle needle (14) and/or the stop surface (20) of the sealing part (17) cooperating therewith is configured in such a way that a dotted or substantially dotted contact surface is formed in an open position of said valve needle (14) between the rear nozzle needle surface (37) and the stop surface (29) of the sealing part (17).

Description

INJEKTOR ZUR EINSPRITZUNG VON KRAFTSTOFF IN BRENNRÄUME VON BRENNKRAFTMASCHINEN, INSBESONDERE SERVOVENTILGESTEUERTER COMMON-RAIL-INJEKTORINJECTOR FOR INJECTION OF FUEL IN COMBUSTION ROOMS OF INTERNAL COMBUSTION ENGINES, IN PARTICULAR SERVO VALVE CONTROLLED COMMON RAIL INJECTOR
Stand der TechnikState of the art
Die Erfindung bezieht sich auf einen Injektor zur Einspritzung von Kraftstoff in Brennräume von Brennkraftmaschinen, insbesondere auf einen sentoventilgesteuerten Common-Rail-Injektor, mit einem Düsenkörper, an dessen brennraumseitigen (freien) Ende ein Düsenaustritt ausgebildet ist, mit einer Düsennadel, die in einer Langsausnehmung des Düsenkörpers axial beweglich bzw. betätigbar angeordnet ist, mit einem das rückwärtige (vom Düsenaustritt abgewandte) Ende der Langsausnehmung abschließenden, (oberhalb) an den Düsenkörper angrenzenden Abschlussteil, welches einen Öffnungsanschlag für die Düsennadel bildet, hierbei mit der rückseitigen (vom Düsenaustritt abgewandten) Stirnfläche der Düsennadel zusammenwirkt und damit den Öffnungshub der Düsennadel begrenzt, und mit einem zwischen der rückwärtigen Düsennadel- Stirnfläche und dem Abschlussteil ausgebildeten Steuerraum, der mit einem der Kraftstoffzuführung dienenden Druckanschluss in hydraulischer Verbindung steht.The invention relates to an injector for injecting fuel into combustion chambers of internal combustion engines, in particular to a sentoventil-controlled common rail injector, with a nozzle body, on the combustion chamber-side (free) end of which a nozzle outlet is formed, with a nozzle needle which is in a longitudinal recess of the nozzle body is arranged to be axially movable or actuatable, with a closing part which closes the rear end (facing away from the nozzle outlet) and (above) adjoins the nozzle body and forms an opening stop for the nozzle needle, here with the rear end (facing away from the nozzle outlet) End face of the nozzle needle cooperates and thus limits the opening stroke of the nozzle needle, and with a control chamber formed between the rear nozzle needle end face and the end part, which is in hydraulic connection with a pressure connection serving the fuel supply TEHT.
Ein CR-lnjektor der vorbezeichneten Art ist durch die DE 199 36 668 A1 bekannt geworden. Bei dem bekannten Injektor ist die mit der ebenflächigen Anschlagfläche des Abschlussteils zusammenwirkende rückseitige Stirnfläche der Düsennadel ebenfalls plan ausgebildet. Der gewünschte Nadelhub wird durch entsprechende Schleifbearbeitung der rückseitigen Düsennadel-Stirnfläche hergestellt. Unter dem Aspekt, dass die Nadelhubtoleranz - wegen Mengenstreuungen der einzelnen Injektoren - möglichst klein sein muss, ergeben sich aus der bekannten Konzeption zweier ebenflächiger Anschlagflächen mehrere Nachteile. Zum einen wirkt es sich nachteilig aus, dass - infolge von Fertigungstoleranzen bei der Herstellung der Düsennadel einerseits und der Führungsbohrung für dieA CR injector of the aforementioned type has become known from DE 199 36 668 A1. In the known injector, the rear end face of the nozzle needle, which cooperates with the flat stop face of the end part, is also flat. The required needle stroke is produced by appropriate grinding of the back face of the nozzle needle. In view of the fact that the needle stroke tolerance has to be as small as possible - because of the quantity scatter of the individual injectors - there are several disadvantages from the known concept of two flat stop surfaces. On the one hand, it has the disadvantage that - due to manufacturing tolerances in the manufacture of the nozzle needle on the one hand and the guide bore for the
Düsennadel im Düsenkörper andererseits - bei der Axialbewegung der Düsennadel geringfügige Seitwärts- bzw. Kippbewegungen der Düsennadel auftreten (sog. „Stirnschlag"). Hierdurch kann sich beim Verdrehen der Düsennadel der Nadelhub verändern und damit die Nadelhubtoleranz vergrößern. Entsprechend nachteilige Auswirkungen hat auch eine toleranzbedingte Schrägsteilung des Abschlussteils zur Führungsbohrung der Düsennadel.Nozzle needle in the nozzle body, on the other hand - slight lateral or tilting movements of the nozzle needle occur during the axial movement of the nozzle needle (so-called "forehead"). As a result, the needle stroke can change when the nozzle needle is rotated, thereby increasing the needle stroke tolerance Oblique division of the end part to the guide hole of the nozzle needle.
Wegen der erforderlichen Flächenauflage des Messtasters beim Einschleifen des Nadelhubs an der Düsennadel ergibt sich eine nachteilige große Einstelltoleranz.Because of the required surface support of the probe when grinding in the needle stroke on the nozzle needle, there is a disadvantageous large setting tolerance.
In Öffnungsstellung der Düsenadel liegt deren rückseitige Stirnfläche plan auf der ebenfalls planen Anschlagfläche des Abschlussteils auf, was eine nachteilige Minimierung des oberhalb der Düsennadel ausgebildeten Steuerraums bedeutet. Hierdurch verringert sich nämlich der stirnseitige Steuerdruck auf die Düsennadel. Die Düsennadel „klebt" und schließt dadurch langsamer mit der nachteiligen Folge, dass die an der Düse austretende Einspritzmenge zu groß ist.In the open position of the nozzle needle, its rear end face lies flat on the likewise flat stop surface of the end part, which means a disadvantageous minimization of the control space formed above the nozzle needle. This reduces the control pressure on the end of the nozzle needle. The nozzle needle "sticks" and thereby closes more slowly, with the disadvantageous consequence that the injection quantity emerging at the nozzle is too large.
Aufgabe der Erfindung ist es, die im Vorstehenden geschilderten Nachteile zu vermeiden, d.h. einen Injektor zu schaffen, der sich durch eine nur minimale Düsennadel-Hubtoleranz und einen konstanten Düsennadelhub, auch bei Verdrehung der Düsennadel sowie durch eine nur vergleichsweise geringe Einstelltoleranz beim Einschleifen des Düsennadelhubs auszeichnet. Vorteile der ErfindungThe object of the invention is to avoid the disadvantages described above, ie to create an injector that is characterized by a minimal nozzle needle stroke tolerance and a constant nozzle needle stroke, even when the nozzle needle is twisted, and by a comparatively small adjustment tolerance when grinding in the nozzle needle stroke distinguished. Advantages of the invention
Gemäß der Erfindung wird die Aufgabe bei einem Injektor der eingangs bezeichneten Gattung dadurch gelöst, dass die rückseitige Stirnfläche der Düsennadel und/oder die mit dieser zusammenwirkende Anschlagfläche des Abschlussteils so ausgebildet ist, dass sich in Öffnungsstellung der Düsennadel eine punktformige oder im Wesentlichen punktformige Berührfläche zwischen der rückseitigen Düsennadel-Stirnfläche und der Anschlagfläche des Abschlusssteils ergibt.According to the invention, the object is achieved in an injector of the type described in the introduction in that the rear end face of the nozzle needle and / or the stop face of the end part interacting therewith is designed such that in the open position of the nozzle needle there is a punctiform or essentially punctiform contact surface between the rear nozzle needle face and the stop surface of the end piece.
Nach einer bevorzugten Ausführungsform der Erfindung, bei der die mit der rückseitigen Düsennadel-Stirnfläche zusammenwirkende Anschlagfläche des Abschlussteils ebenflächig ausgebildet ist, soll die Düsennadel eine ballige, vorzugsweise kugelförmige, rückseitige Stirnfläche aufweisen.According to a preferred embodiment of the invention, in which the abutment surface of the end part which interacts with the rear nozzle needle end face is flat, the nozzle needle should have a spherical, preferably spherical, rear end face.
Durch die erfindungsgemäßen Maßnahmen entsteht am oberen Anschlag der Düsennadel, d.h. in Öffnungsstellung derselben, eine (nahezu) punktformige Berührfläche zwischen dem Abschlussteil und der rückseitigen (oberen) Stirnfläche der Düsennadel. Dadurch werden - ohne großen technischen Aufwand - die oben geschilderten Unzulänglichkeiten bekannter Injektoren der in Rede stehenden Art beseitigt. So gelingt es, die Hubtoleranz der Düsennadel von +_ 0,01 mm auf +_ 0,003 mm zu reduzieren. Insbesondere wird das unerwünschte „Kleben" der Düsennadel am Anschlag in ihrer Öffnungsstellung verhindert, was eine größere Sparsamkeit bei den vom Injektor geförderten Einspritzmengen bedeutet.The measures according to the invention result at the upper stop of the nozzle needle, i.e. in the open position thereof, an (almost) punctiform contact surface between the end part and the rear (upper) end face of the nozzle needle. As a result, the shortcomings described above of known injectors of the type in question are eliminated without great technical effort. This enables the stroke tolerance of the nozzle needle to be reduced from + _ 0.01 mm to + _ 0.003 mm. In particular, the undesired "sticking" of the nozzle needle to the stop in its open position is prevented, which means greater economy in the injection quantities delivered by the injector.
Um plastische Verformungen an den zusammenwirkenden Flächen der Düsennadel einerseits und des Abschlussteils andererseits zu vermeiden, sollte der Radius der rückseitigen Düsennadel-Stirnfläche dort, wo diese mit der Anschlagfläche des Abschlussteils in Berührung kommt, so bemessen sein, dass - unter Berücksichtigung der auf die Düsennadel wirkenden Öffnungskraft - die zulässige Hertz' sehe Pressung nicht überschritten wird. ZeichnungIn order to avoid plastic deformations on the interacting surfaces of the nozzle needle on the one hand and the end part on the other hand, the radius of the rear end of the nozzle needle should be dimensioned where it comes into contact with the stop surface of the end part so that - taking into account that on the nozzle needle effective opening force - the permissible Hertz 'see pressure is not exceeded. drawing
Zur Veranschaulichung der Erfindung dient ein Ausführungsbeispiel, das in der Zeichnung dargestellt und im Folgenden detailliert beschrieben ist. Es zeigt:An exemplary embodiment is used to illustrate the invention, which is shown in the drawing and described in detail below. It shows:
Fig. 1 eine Ausführungsform eines CR-Injektors, im vertikalen Längsschnitt, undFig. 1 shows an embodiment of a CR injector, in vertical longitudinal section, and
Fig. 2 die Einzelheit „A" aus Fig. 1 in gegenüber Fig. 1 vergrößerterFIG. 2 shows the detail “A” from FIG. 1 in an enlarged manner compared to FIG. 1
Darstellung.Presentation.
Beschreibung des AusführungsbeispielsDescription of the embodiment
Es bezeichnet 10 insgesamt einen mehrfach abgesetzten Düsenkörper mit einer zentrischen Langsausnehmung 11 , die sich an ihrem unteren Ende zu einem Düsenaustritt 12 verengt. Oberhalb des Düsenaustritts 12 bildet die Langsausnehmung 11 einen konischen Ventilsitz 13. In der Langsausnehmung 11 . ist eine insgesamt mit 14 bezifferte Düsennadel axialbeweglich angeordnet. Ein unteres, verjüngtes Ende 15 der Düsennadel 14 ist konisch ausgebildet und wirkt mit dem ebenfalls konischen Ventilsitz 13 zusammen.It designates 10 as a whole a multi-offset nozzle body with a central longitudinal recess 11 which narrows at its lower end to form a nozzle outlet 12. Above the nozzle outlet 12, the longitudinal recess 11 forms a conical valve seat 13. In the longitudinal recess 11. a nozzle needle, numbered 14 overall, is arranged to be axially movable. A lower, tapered end 15 of the nozzle needle 14 is conical and interacts with the likewise conical valve seat 13.
Oberhalb des Ventilkörpers 10 und dichtend auf dessen oberer Stirnfläche 16 aufsitzend ist ein scheibenförmiges Abschlussteil 17 angeordnet. An das Abschlussteil 17 schließt sich oben - ebenfalls dichtend - ein Servoventilkörper 18 an, in dem ein - z.B. piezoelektrisch betätigtes - Servoventil 19 aufgenommen ist. Ventilkörper 10, Abschlussteil 17 und Servoventilkörper 18 sind von einem Injektorgehäuse 20 umschlossen und in der aus Fig. 1 ersichtlichen Zuordnung fixiert.Above the valve body 10 and seated sealingly on its upper end face 16, a disc-shaped end part 17 is arranged. The end part 17 is adjoined at the top - likewise sealingly - by a servo valve body 18, in which a servo valve 19, for example a piezoelectrically operated one, is received. Valve body 10, end part 17 and servo valve body 18 are enclosed by an injector housing 20 and fixed in the assignment shown in FIG. 1.
Wie des Weiteren aus Fig. 1 hervorgeht, ist in den Servoventilkörper 18 ein Hochdruckkanal 21 eingearbeitet, der - über einen (nicht gezeigten) Hochdruckanschluss - mit einem (ebenfalls nicht dargestellten) Kraftstoff- Hochdruckspeicher (sog. Common-Rail) in hydraulischer Verbindung steht. Der Hochdruckkanal 21 mündet - über eine Erweiterung 22 - an der unteren Stirnfläche 23 des Servoventilkörpers 18 aus und ist dort mit zwei in dasAs can further be seen from FIG. 1, a high-pressure channel 21 is incorporated into the servo valve body 18, which - via a (not shown) high-pressure connection - is in hydraulic connection with a (also not shown) fuel high-pressure accumulator (so-called common rail) , The high-pressure duct 21 opens out - via an extension 22 - on the lower end face 23 of the servo valve body 18 and is there with two into it
Abschlussteil 17 eingearbeiteten Bohrungen 24 und 25 hydraulisch verbunden. Durch die erste Bohrung 24 gelangt der unter Hochdruck stehende Kraftstoff - über einen Ringraum 26 - in die Langsausnehmung 11 des Düsenkörpers 10 und damit - bei geöffnetem Ventil 13, 15 - zum Düsenaustritt 12.End part 17 incorporated holes 24 and 25 hydraulically connected. The high-pressure fuel passes through the first bore 24 - via an annular space 26 - into the longitudinal recess 11 of the nozzle body 10 and thus - with the valve 13, 15 open - to the nozzle outlet 12.
Eine Besonderheit bei der zweiten Bohrung 25 besteht darin, dass diese sich stufenförmig zu einer Drosselbohrung 27 (sog. Zulaufdrossel) verengt. Über diese Zulaufdrossel 27 gelangt Kraftstoff in einen Steuerraum 28, der sich zwischen dem oberen Ende der Düsennadel 14 und der mit 29 bezifferten unteren Stirnfläche des Abschlussteils 17 erstreckt. Der Steuerraum 28 erreicht sein maximales Volumen bei der aus Fig. 1 und Fig. 2 ersichtlichen Schließstellung der Düsennadel 14, wobei diese mit ihrem konusförmigen Ende 15 dichtend mit dem Ventilsitz 13 in Anlage steht. In dieser Schließstellung wird die Düsennadel 14 zum einen durch den im Steuerraum 28 herrschenden Flüssigkeitsdruck und zum anderen durch eine Druckfeder 30 gehalten. Diese stützt sich hierbei mit ihrem oberen Ende über ein das obere Ende der Düsennadel 14 dichtend umschließendes Hülsenteil 31 an der unteren Stirnfläche 29 des Abschlussteils 17 ab. Ihre - in Pfeilrichtung 32 gerichtete - Schließkraft übt die Druckfeder 30 über ein weiteres Hülsenteil 33, das sich auf einem Absatz 34 der Düsennadel 14 abstützt, auf die Düsennadel 14 aus.A special feature of the second bore 25 is that it narrows in steps to a throttle bore 27 (so-called inlet throttle). Via this inlet throttle 27, fuel reaches a control chamber 28 which extends between the upper end of the nozzle needle 14 and the lower end face of the end part 17, numbered 29. The control chamber 28 reaches its maximum volume when the nozzle needle 14 is in the closed position shown in FIGS. 1 and 2, the conical end 15 of which is sealingly in contact with the valve seat 13. In this closed position, the nozzle needle 14 is held on the one hand by the liquid pressure prevailing in the control chamber 28 and on the other hand by a compression spring 30. This is supported with its upper end on a sleeve part 31 sealingly enclosing the upper end of the nozzle needle 14 on the lower end face 29 of the end part 17. Yours - in the direction of the arrow 32 directional - closing force exerts the compression spring 30 on the nozzle needle 14 via a further sleeve part 33, which is supported on a shoulder 34 of the nozzle needle 14.
In das Abschlussteil 17 ist eine weitere Bohrung 35 eingearbeitet, die einerseits über Bohrung 24 und Ringraum 26 - mit dem Hochdruckkanal 21 und andererseits - über eine Drosselbohrung 36 (sog. Ablaufdrossel) - mit dem Servoventil 19 in hydraulischer Wirkverbindung steht.In the end part 17, a further bore 35 is machined, which is on the one hand via bore 24 and annular space 26 - with the high-pressure duct 21 and on the other hand - via a throttle bore 36 (so-called discharge throttle) - with the servo valve 19 in hydraulic operative connection.
Eine wesentliche Besonderheit des dargestellten Ausführungsbeispiels besteht nun darin, dass die - mit 37 bezifferte - rückseitige (obere) Stirnfläche der Düsennadel 14 eine kugelförmige Krümmung aufweist. Der Kugelradius ist in Fig. 1 und 2 mit rkugeι bezeichnet. Durch den Scheitelpunkt P (s. Fig. 2) der Kugelfläche 37 wird der obere Anschlag der Düsennadel 14, welcher mit der Fläche 29 des Abschlussteils 17 als Gegenanschlag zusammenwirkt, bestimmt. Ausgehend von der Schließstellung der Düsennadel 14 (s. Fig. 1 und 2) ergibt sich daraus der - in Fig. 2 mit hDN bezeichnete - Düsennadelhub. In ihrer (oberen) Öffnungsstellung kommt die Düsennadel 14 somit am Punkt P mit der Fläche 29 des Abschlussteils 17 zur Anlage. Durch die - infolge der kugelförmig/balligen Gestaltung der Stirnfläche 37 der Düsennadel 14 gelungene -Vermeidung einer (groß-)flächigen Anlage der Düsennadel 14 an der Anschlagfläche 29 des Abschlussteils 17 wird ein - andernfalls mögliches - „Kleben" der Düsennadel 14 in ihrer (oberen) Öffnungsstellung verhindert. Außerdem sorgt die kugelförmig/ballige Düsennadel- Stirnfläche 37 dafür, dass auch in Öffnungsstellung der Düsennadel 14 noch ein ausreichend großer Steuerraum 28 verbleibt. Die kugelförmig/ballige Gestaltung der Düsennadel-Stirnfläche 37 mit dem daraus resultierenden nahezu punktförmigen Düsennadelanschlag erbringt darüber hinaus den Vorteil, dass der Düsennadelhub hDN bei einem etwaigen Verdrehen der Düsennadel 14 oder bei durch Fertigungstoleranzen bedingter Schrägstellung derselben stets konstant bleibt. An essential special feature of the exemplary embodiment shown is that the rear (upper) end face of the nozzle needle 14, numbered 37, has a spherical curvature. The spherical radius is shown in Fig. 1 and 2 are denoted by r kuge ι. The apex P (see FIG. 2) of the spherical surface 37 determines the upper stop of the nozzle needle 14, which interacts with the surface 29 of the end part 17 as a counter stop. Starting from the closed position of the nozzle needle 14 (see FIGS. 1 and 2), this results in the nozzle needle stroke — denoted by h DN in FIG. 2. In its (upper) open position, the nozzle needle 14 thus comes to rest at point P with the surface 29 of the end part 17. Because of the spherical / spherical design of the end face 37 of the nozzle needle 14, the avoidance of a (large) surface contact of the nozzle needle 14 on the stop face 29 of the end part 17 results in an - otherwise possible - "sticking" of the nozzle needle 14 in its ( In addition, the spherical / spherical nozzle needle end face 37 ensures that a sufficiently large control space 28 remains in the open position of the nozzle needle 14. The spherical / spherical design of the nozzle needle end face 37 results in the resulting almost punctiform nozzle needle stop moreover the advantage that the nozzle needle stroke h DN always remains constant in the event of any rotation of the nozzle needle 14 or when it is inclined due to manufacturing tolerances.

Claims

PATENTANSPRÜCHE
1. Injektor zur Einspritzung von Kraftstoff in Brennräume von1. Injector for injecting fuel into combustion chambers of
Brennkraftmaschinen, insbesondere servoventilgesteuerter Common-Rail- Injektor, mit einem Düsenkörper (10), an dessen brennraumseitigen (freien) Ende ein Düsenaustritt (12) ausgebildet ist, mit einer Düsennadel (14), die in einer Langsausnehmung (11) des Düsenkörpers (10) axial beweglich bzw. betätigbar angeordnet ist, mit einem das rückwärtige (vom Düsenaustritt (12) abgewandte) Ende der Langsausnehmung (11) abschließenden, (oberhalb) an den Düsenkörper (10) angrenzenden Abschlussteil (17), welches einen Öffnungsanschlag (29) für die Düsennadel (14) bildet, hierbei mit der rückseitigen (vom Düsenaustritt (12) abgewandten) Stirnfläche (37) derInternal combustion engines, in particular servo-valve-controlled common rail injector, with a nozzle body (10), on the combustion chamber-side (free) end of which a nozzle outlet (12) is formed, with a nozzle needle (14), which is located in a longitudinal recess (11) of the nozzle body (10 ) is arranged to be axially movable or actuatable, with a closing part (17) which closes the rear end (facing away from the nozzle outlet (12)) of the longitudinal recess (11) and (above) adjoins the nozzle body (10) and which has an opening stop (29) forms for the nozzle needle (14), in this case with the rear end face (37 facing away from the nozzle outlet (12))
Düsennadel (14) zusammenwirkt und damit den Öffnungshub (hDN) der Düsennadel (14) begrenzt, und mit einem zwischen der rückwärtigen Düsennadel-Stirnfläche (37) und dem Abschlussteil (17) ausgebildeten Steuerraum (28), der mit einem der Kraftstoffzuführung dienenden Druckanschluss (21) in hydraulischer Verbindung steht, dadurch gekennzeichnet, dass die rückseitige Stirnfläche (37) der Düsennadel (14) und/oder die mit dieser zusammenwirkende Anschlagfläche (29) des Abschlussteils (17) so ausgebildet ist, dass sich in Öffnungsstellung der Düsennadel (14) eine punktformige oder im Wesentlichen punktformige Berührfläche (P) zwischen der rückseitigen Düsennadel-Stirnfläche (37) und derNozzle needle (14) interacts and thus limits the opening stroke (h DN ) of the nozzle needle (14), and with a control chamber (28) formed between the rear end of the nozzle needle (37) and the end part (17), which is used to supply the fuel Pressure connection (21) is in hydraulic connection, characterized in that the rear end face (37) of the nozzle needle (14) and / or the stop face (29) of the end part (17) cooperating with it is designed such that the nozzle needle is in the open position (14) a point-shaped or essentially point-shaped contact surface (P) between the rear nozzle needle end face (37) and the
Anschlagfläche (29) des Abschlussteils (17) ergibt.Stop surface (29) of the end part (17) results.
2. Injektor nach Anspruch 1 , wobei die mit der rückseitigen Düsennadel-Stirnfläche (37) zusammenwirkende Anschlagfläche (29) des Abschlussteils (17) ebenflächig ausgebildet ist, dadurch gekennzeichnet, dass die Düsennadel (14) eine ballig ausgebildete rückseitige Stirnfläche (37) aufweist. 2. Injector according to claim 1, wherein the stop surface (29) of the end part (17) cooperating with the rear nozzle needle end face (37) is flat, characterized in that the nozzle needle (14) has a crowned rear end face (37) ,
3. Injektor nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass die rückseitige Stirnfläche (37) der Düsennadel (14) kugelförmig ausgebildet ist (Fig. 1 und 2).3. Injector according to claim 1 or 2, characterized in that the rear end face (37) of the nozzle needle (14) is spherical (Fig. 1 and 2).
4. Injektor nach Anspruch 1 , 2 oder 3, dadurch gekennzeichnet, dass der Radius (r kugei) der rückseitigen Düsennadel-Stirnfläche (37) dort, wo diese mit der4. Injector according to claim 1, 2 or 3, characterized in that the radius ( r ball i) d he rear nozzle needle end face (37) where this with the
Anschlagfläche (29) des Abschlussteils (17) in Berührung kommt (P), so bemessen ist, dass - unter Berücksichtigung der auf die Düsennadel (14) wirkenden Öffnungs kraft - die zulässige Hertz' sehe Pressung nicht überschritten wird. Stop face (29) of the end part (17) comes into contact (P), so dimensioned that - taking into account the opening force acting on the nozzle needle (14) - the permissible Hertz 'see pressure is not exceeded.
EP03794766A 2002-09-06 2003-06-26 Injector, especially a common rail injector controlled by a servo valve, for injecting fuel into the combustion chambers of internal combustion engines Withdrawn EP1537327A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10241462 2002-09-06
DE10241462A DE10241462A1 (en) 2002-09-06 2002-09-06 Fuel injector for internal combustion engines has end face of nozzle needle and/or stop face of shut-off component interacting with it constructed so that in open position of nozzle needle point-form contact face is formed between them
PCT/DE2003/002129 WO2004025114A1 (en) 2002-09-06 2003-06-26 Injector, especially a common rail injector controlled by a servo valve, for injecting fuel into the combustion chambers of internal combustion engines

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EP1537327A1 true EP1537327A1 (en) 2005-06-08

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EP03794766A Withdrawn EP1537327A1 (en) 2002-09-06 2003-06-26 Injector, especially a common rail injector controlled by a servo valve, for injecting fuel into the combustion chambers of internal combustion engines

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EP (1) EP1537327A1 (en)
JP (1) JP2005538296A (en)
KR (1) KR20050040936A (en)
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AT500774B8 (en) * 2004-08-06 2007-02-15 Bosch Gmbh Robert DEVICE FOR INJECTING FUEL IN THE COMBUSTION ENGINE OF AN INTERNAL COMBUSTION ENGINE
JP2007315186A (en) * 2006-05-23 2007-12-06 Aisan Ind Co Ltd Fuel injection device
DE102008003348A1 (en) * 2008-01-07 2009-07-09 Robert Bosch Gmbh fuel injector
FR2965018A1 (en) * 2010-09-20 2012-03-23 Renault Sas DYNAMIC LEAK INJECTOR REDUCED
CN102330627A (en) * 2011-10-16 2012-01-25 中国兵器工业集团第七0研究所 Oil nozzle for common rail injector of flat dual-opposed diesel engine
DE102014221586A1 (en) * 2014-10-23 2016-04-28 Robert Bosch Gmbh fuel injector
CN106677945B (en) * 2016-07-12 2019-07-05 江西汇尔油泵油嘴有限公司 The atomizer of oil spout and stage by stage fuel injecting method stage by stage
FR3057623B1 (en) * 2016-10-14 2020-12-25 Delphi Int Operations Luxembourg Sarl FUEL INJECTOR VALVE MEMBER
CN112431699B (en) * 2020-11-12 2021-12-24 一汽解放汽车有限公司 Matching parts high pressure flow measuring device of long needle valve fuel sprayer

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DE60015218T2 (en) * 1999-04-01 2006-02-16 Delphi Technologies, Inc., Troy Fuel injector
DE19936668A1 (en) * 1999-08-04 2001-02-22 Bosch Gmbh Robert Common rail injector
DE10020166A1 (en) * 2000-04-25 2001-10-31 Bosch Gmbh Robert Nozzle needle stroke adjustment on injectors of injection systems

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KR20050040936A (en) 2005-05-03
JP2005538296A (en) 2005-12-15
DE10241462A1 (en) 2004-03-18

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