EP0606436A1 - Fuel injection nozzle for internal combustion engines. - Google Patents

Fuel injection nozzle for internal combustion engines.

Info

Publication number
EP0606436A1
EP0606436A1 EP93915674A EP93915674A EP0606436A1 EP 0606436 A1 EP0606436 A1 EP 0606436A1 EP 93915674 A EP93915674 A EP 93915674A EP 93915674 A EP93915674 A EP 93915674A EP 0606436 A1 EP0606436 A1 EP 0606436A1
Authority
EP
European Patent Office
Prior art keywords
valve needle
piston
stroke
pressure
pressure chamber
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP93915674A
Other languages
German (de)
French (fr)
Other versions
EP0606436B1 (en
Inventor
Karl Hofmann
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 EP0606436A1 publication Critical patent/EP0606436A1/en
Application granted granted Critical
Publication of EP0606436B1 publication Critical patent/EP0606436B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • F02M45/00—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship
    • F02M45/02—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship with each cyclic delivery being separated into two or more parts
    • F02M45/04—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship with each cyclic delivery being separated into two or more parts with a small initial part, e.g. initial part for partial load and initial and main part for full load
    • F02M45/08—Injectors peculiar thereto

Definitions

  • the invention relates to a fuel injection nozzle according to the preamble of claim 1.
  • Injectors of this type have a pre-injection and a main injection by means of stroke control of the valve needle to reduce the combustion noise.
  • the fuel injector according to the invention with the characterizing features of claim 1 has the advantage that Achieving a stepped opening stroke of the closing needle down to the piston, the same parts are used as in a single-spring holder, the piston being formed by a special but nevertheless easy to manufacture design of the pressure pin transmitting the closing force of the closing spring to the valve needle.
  • FIG. 1 shows an injection nozzle in longitudinal section
  • FIG. 2 shows a detail A from FIG. 1 on an enlarged scale, left in the closed and right in the open position of the valve needle
  • FIG. 3 shows an alternative to the exemplary embodiment according to FIG. 2, also on the left in the closed and on the right in the open position of the valve needle.
  • the injection nozzle has a nozzle body 10 which is clamped together with an intermediate disk 11 with a union nut 13 to a holding body 12.
  • a valve needle 15 is slidably mounted in the nozzle body 10 and cooperates with a valve seat 16 which is turned inwards in the nozzle body 10 and is arranged in front of a plurality of spray openings 17.
  • the guide bore 18 of the valve needle 15 is, as usual, expanded at one point to a pressure chamber 19, in the area of which the valve needle 15 has a pressure shoulder 19 and which is connected via a channel 22 and a filter body 23 to a connecting piece 24 on the holding body 12 for connecting a fuel line is.
  • the fuel acting on the pressure shoulder 20 of the valve needle 15 pushes the valve needle 15 upward against the graduated force curve of a closing force arrangement described below, the fuel being injected through the injection openings 17 in a pre-injection phase and a main injection phase.
  • a spring chamber 26 is formed in the holding body 12 for receiving a closing spring 27, which is supported on the one hand by a disk 28 at the bottom of the chamber 26 and on the other hand on a pressure piece 29.
  • the pressure piece 29 rests on a piston 30 which is tightly guided in a cylindrical through bore 31 in the intermediate disk 11.
  • the piston 30 passes through the through hole 31 completely and is supported on the valve needle 15, which loads it in the closing direction.
  • a longitudinal groove 35 connects in the jacket of the piston 30 this pressure chamber 33 temporarily with the spring chamber 26, which is relieved of pressure via a leak channel 38 and a connecting piece 39.
  • the longitudinal groove 35 is delimited by a control edge 36 which, in the closed position of the valve needle 15 and piston 30 supported thereon, is at a distance from the annular edge 37 at the transition of the partial surface into the through bore 31 of the intermediate disk 11 hv, which corresponds to the required advance stroke of the valve needle 11.
  • a flat abrasion for example a surface grinding, can alternatively be arranged on the piston 30.
  • the diameter d or the hydraulic effective area of the piston 30 K is smaller than the diameter D ⁇ or the effective area of the valve
  • the end face 41 of the valve needle 15 delimiting the pressure chamber 33 is flat and the opposite end face 42 of the piston 30 is spherical.
  • the valve needle 15 has, as usual, a pressure pin 44 which is offset over a shoulder 43 and which projects with play into a blind bore 45 of the piston 30 and supports it on the base 46 of the blind bore 45.
  • the known injection nozzle works as follows: When fuel is supplied from an injection pump through the channel 22 into the pressure chamber 19, when a certain opening pressure is reached, the valve needle 15 becomes counter to the action of the closing spring 27, which loads the valve needle 15 indirectly via the piston 30 , lifted off the valve seat 16; injection begins. With increasing pressure, the valve needle 15 continues to lift off the valve seat 16 and thereby moves the piston 30 until its control edge 36, after a preliminary stroke h, the v
  • the piston 30 since the effective area of the piston 30 is smaller than that of the valve needle 15, and thus at the end of the advance stroke h the force generated by the piston 30 is smaller than the force generated by the valve needle 15, which is the same as the closing spring force, the piston 30 remains so long in contact with the valve needle 15 until the supply pressure and thus also the control pressure in the pressure chamber 33 have risen so far that the force generated by the piston 30 exceeds the pretensioning force of the closing spring 27 reached at the end of the forward stroke in the preliminary stroke position. During this time, the valve needle 15 also remains in the pre-stroke position.
  • the effective area of the piston 30 is smaller than that of the valve needle 15, the travel of the piston 30 becomes greater than that of the valve needle 15 after the advance stroke h has been covered. ge that the closing force exerted by the piston 30 via the hydraulic cushion in the pressure chamber 33 on the valve needle 15 increases with the same spring stiffness, the characteristic of the described injector thus corresponds to that of a two-spring holder.

Landscapes

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

Abstract

Un injecteur de carburant pour moteurs à combustion interne pour préinjection/injection principale comporte un pointeau (15) s'ouvrant vers l'intérieur qui est taré par un seul ressort de fermeture (27). Après une précourse (hv) pendant laquelle la pression d'alimentation commande la course en liaison avec la surface active du pointeau (15), il y a inversion de course sur un piston intercalé (30) dont la surface active est moins grande que celle du pointeau (15). En raison de la force du piston (30) qui tend le ressort de fermeture (27), proportionnellement réduite par rapport à la force du pointeau, ce dernier s'ouvre de manière plus plate après la précourse (hv) que pendant la précourse.A fuel injector for internal combustion engines for pre-injection/main injection comprises an inwardly opening needle valve (15) which is calibrated by a single closing spring (27). After a pre-stroke (hv) during which the supply pressure controls the stroke in conjunction with the active surface of the needle (15), there is stroke reversal on an interposed piston (30) whose active surface is smaller than that of the needle (15). Due to the force of the piston (30) which tensions the closing spring (27), proportionally reduced compared to the force of the needle valve, the latter opens flatter after the pre-stroke (hv) than during the pre-stroke.

Description

Kraftstoff-Einspritzdüse für BrennkraftmaschinenFuel injection nozzle for internal combustion engines
Stand der TechnikState of the art
Die Erfindung bezieht sich auf eine Kraftstoff-Einspritzdüse nach der Gattung des Anspruchs 1. Einspritzdüsen dieser Gattung haben zum Senken des Verbrennungsgeräusches eine Vor- und eine Hauptein¬ spritzung durch Hubsteuerung der Ventilnadel .The invention relates to a fuel injection nozzle according to the preamble of claim 1. Injectors of this type have a pre-injection and a main injection by means of stroke control of the valve needle to reduce the combustion noise.
Bei einer durch die EP-A 240 683 bekannten Einspritzdüse dieser Art stößt die Ventilnadel am Ende des Vorhubs am Kolben der Drucküber¬ tragungseinrichtung an, der die Weiterbewegung der Ventilnadel stoppt, bis der Kraftstoffdruck so weit angestiegen ist, daß seine in Öffnungsrichtung auf die Ventilnadel ausgeübte Kraft die Kraft der Schließfeder und die vom Kolben ausgeübte Kraft überträgt. Die bekannte Einspritzdüse baut zwar klein, jedoch unterliegt die Zwischenwand wegen der Ausbildung der Druckkammer und deren An¬ schlußkanal einem komplizierten Fertigungsverfahren.In the case of an injection nozzle of this type known from EP-A 240 683, the valve needle abuts the piston of the pressure transmission device at the end of the forward stroke, which stops the further movement of the valve needle until the fuel pressure has risen to such an extent that it presses on the valve needle in the opening direction applied force transmits the force of the closing spring and the force exerted by the piston. Although the known injection nozzle is small, the intermediate wall is subject to a complicated manufacturing process due to the formation of the pressure chamber and its connecting channel.
Vorteile der ErfindungAdvantages of the invention
Die erfindungsgemäße Kraftstoff-Einspritzdüse mit den kennzeich¬ nenden Merkmalen des Anspruchs 1 hat den Vorteil, daß zum Erzielen eines gestuften Öffnungshubes der Schließnadel bis auf den Kolben die gleichen Teile wie bei einem Ein-Federhalter verwendet sind, wobei der Kolben durch besondere, aber dennoch einfach her¬ stellbare Gestaltung des die Schießkraft der Schließfeder auf die Ventilnadel übertragenden Druckbolzens gebildet ist.The fuel injector according to the invention with the characterizing features of claim 1 has the advantage that Achieving a stepped opening stroke of the closing needle down to the piston, the same parts are used as in a single-spring holder, the piston being formed by a special but nevertheless easy to manufacture design of the pressure pin transmitting the closing force of the closing spring to the valve needle.
Durch die in den Unteransprüchen enthaltenen Merkmale sind vorteil¬ hafte Weiterbildungen der Einspritzdüse nach dem Anspruch 1 möglich.Advantageous developments of the injection nozzle according to claim 1 are possible due to the features contained in the subclaims.
Zeichnungdrawing
Ausführungsbeispiele der Erfindung sind in der Zeichnung dargestellt und werden im folgenden näher beschrieben. Es zeigen Figur 1 eine Einspritzdüse im Längsschnitt, Figur 2 einen Ausschnitt A aus Figur 1 in vergrößertem Maßstab, links in Schließ- und rechts in Offen¬ stellung der Ventilnadel, und Figur 3 eine Alternative zu dem Aus¬ führungsbeispiel nach Figur 2, ebenfalls links in Schließ- und rechts in Offenstellung der Ventilnadel.Embodiments of the invention are shown in the drawing and are described in more detail below. FIG. 1 shows an injection nozzle in longitudinal section, FIG. 2 shows a detail A from FIG. 1 on an enlarged scale, left in the closed and right in the open position of the valve needle, and FIG. 3 shows an alternative to the exemplary embodiment according to FIG. 2, also on the left in the closed and on the right in the open position of the valve needle.
Beschreibung der AusführungsbeispieleDescription of the embodiments
Die Einspritzdüse hat einen Düsenkörper 10, der zusammen mit einer Zwischenscheibe 11 mit einer Überwurfmutter 13 an einem Haltekörper 12 festgespannt ist. Im Düsenkörper 10 ist eine Ventilnadel 15 ver¬ schiebbar gelagert, die mit einem nach innen gekehrten Ventilsitz 16 im Düsenkörper 10 zusammenarbeitet, der mehreren Spritzöffnungen 17 vorgelagert ist. Die Führungsbohrung 18 der Ventilnadel 15 ist wie üblich an einer Stelle zu einem Druckraum 19 erweitert, in dessen Bereich die Ventilnadel 15 eine Druckschulter 19 hat und der über einen Kanal 22 und einen Filterkörper 23 mit einem Stutzen 24 am Haltekörper 12 zum Anschließen einer Kraftstoffleitung verbunden ist. Der an der Druckschulter 20 der Ventilnadel 15 angreifende Kraftstoff schiebt die Ventilnadel 15 entgegen dem abgestuften Kraftverlauf einer im folgenden beschriebenen Schließkraftanordnung nach oben, wobei der Kraftstoff in einer Voreinspritzphase und einer Haupteinspritzphase durch die Spritzöffnungen 17 ausgespritzt wird.The injection nozzle has a nozzle body 10 which is clamped together with an intermediate disk 11 with a union nut 13 to a holding body 12. A valve needle 15 is slidably mounted in the nozzle body 10 and cooperates with a valve seat 16 which is turned inwards in the nozzle body 10 and is arranged in front of a plurality of spray openings 17. The guide bore 18 of the valve needle 15 is, as usual, expanded at one point to a pressure chamber 19, in the area of which the valve needle 15 has a pressure shoulder 19 and which is connected via a channel 22 and a filter body 23 to a connecting piece 24 on the holding body 12 for connecting a fuel line is. The fuel acting on the pressure shoulder 20 of the valve needle 15 pushes the valve needle 15 upward against the graduated force curve of a closing force arrangement described below, the fuel being injected through the injection openings 17 in a pre-injection phase and a main injection phase.
Im Haltekörper 12 ist eine Federkammer 26 zur Aufnahme einer Schließfeder 27 gebildet, die sich einerseits über eine Scheibe 28 am Boden der Kammer 26 und andererseits auf einem Druckstück 29 ab¬ stützt. Das Druckstück 29 liegt auf einem Kolben 30 auf, der in einer zylindrischen Durchgangsbohrung 31 in der Zwischenscheibe 11 dicht geführt ist. Der Kolben 30 durchsetzt die Durchgangsbohrung 31 vollständig und stützt sich auf der Ventilnadel 15, diese in Schließrichtung belastend, ab.A spring chamber 26 is formed in the holding body 12 for receiving a closing spring 27, which is supported on the one hand by a disk 28 at the bottom of the chamber 26 and on the other hand on a pressure piece 29. The pressure piece 29 rests on a piston 30 which is tightly guided in a cylindrical through bore 31 in the intermediate disk 11. The piston 30 passes through the through hole 31 completely and is supported on the valve needle 15, which loads it in the closing direction.
Die einander zugewandten Seiten des Kolbens 30 und der Ventilnadel 15 begrenzen zusammen mit einer Erweiterung 32 der Führungsbohrung 18 im Düsenkörper 10 nahe der Zwischenscheibe 11 und einer nahe¬ liegenden Teilfläche der Zwischenscheibe 11 eine Druckkammer 33. Eine L ngsnut 35 im Mantel des Kolbens 30 verbindet diese Druck¬ kammer 33 zeitweise mit der Federkammer 26, die über einen Leckkanal 38 und einen Anschlußstutzen 39 druckentlastet ist. Nahe der die Druckkammer 33 begrenzenden Seite des Kolbens 30 ist die Längsnut 35 von einer Steuerkante 36 begrenzt, welche in Schließstellung der Ventilnadel 15 und sich auf dieser abstützendem Kolben 30 von der Ringkante 37 am Übergang der Teilfläche in die Durchgangsbohrung 31 der Zwischenscheibe 11 einen Abstand hv hat, der dem erforder- liehen Vorhub der Ventilnadel 11 entspricht. Anstelle einer L ngsnut 35 im Umfang des Kolbens 30 kann alternativ auch eine flache Ab¬ tragung, beispielsweise ein Flächenanschliff am Kolben 30 angeordnet sein. Der Durchmesser d bzw. die hydraulische Wirkfläche des Kolbens 30 K ist kleiner als der Durchmesser Dτ bzw. die Wirkfläche der Ven-The mutually facing sides of the piston 30 and the valve needle 15, together with an extension 32 of the guide bore 18 in the nozzle body 10, delimit a pressure chamber 33 near the intermediate disk 11 and a nearby partial surface of the intermediate disk 11. A longitudinal groove 35 connects in the jacket of the piston 30 this pressure chamber 33 temporarily with the spring chamber 26, which is relieved of pressure via a leak channel 38 and a connecting piece 39. Near the side of the piston 30 which delimits the pressure chamber 33, the longitudinal groove 35 is delimited by a control edge 36 which, in the closed position of the valve needle 15 and piston 30 supported thereon, is at a distance from the annular edge 37 at the transition of the partial surface into the through bore 31 of the intermediate disk 11 hv, which corresponds to the required advance stroke of the valve needle 11. Instead of a longitudinal groove 35 in the circumference of the piston 30, a flat abrasion, for example a surface grinding, can alternatively be arranged on the piston 30. The diameter d or the hydraulic effective area of the piston 30 K is smaller than the diameter D τ or the effective area of the valve
N tilnadel 15. Beim Ausführungsbeispiel nach Figur 2 sind die die Druckkammer 33 begrenzende Stirnseite 41 der Ventilnadel 15 eben und die gegenüberliegende Stirnseite 42 des Kolbens 30 ballig ausge¬ bildet. Alternativ dazu hat beim Ausführungsbeispiel nach Figur 3 die Ventilnadel 15, wie auch üblich, einen über eine Schulter 43 ab¬ gesetzten Druckzapfen 44, der mit Spiel in eine Sackbohrung 45 des Kolbens 30 ragt und diesen am Grund 46 der Sackbohrung 45 abstützt.In the exemplary embodiment according to FIG. 2, the end face 41 of the valve needle 15 delimiting the pressure chamber 33 is flat and the opposite end face 42 of the piston 30 is spherical. As an alternative to this, in the exemplary embodiment according to FIG. 3, the valve needle 15 has, as usual, a pressure pin 44 which is offset over a shoulder 43 and which projects with play into a blind bore 45 of the piston 30 and supports it on the base 46 of the blind bore 45.
Die bekannte Einspritzdüse arbeitet wie folgt: Beim Zuführen von Kraftstoff von einer Einspritzpumpe durch den Kanal 22 in den Druck¬ raum 19 wird bei Erreichen eines bestimmten Öffnungsdruckes die Ventilnadel 15 entgegen der Wirkung der Schließfeder 27, welche die Ventilnadel 15 mittelbar über den Kolben 30 belastet, vom Ventilsitz 16 abgehoben; die Einspritzung beginnt. Bei steigendem Druck hebt die Ventilnadel 15 weiter vom Ventilsitz 16 ab und verschiebt dabei den Kolben 30, bis dessen Steuerkante 36 nach einem Vorhub h die vThe known injection nozzle works as follows: When fuel is supplied from an injection pump through the channel 22 into the pressure chamber 19, when a certain opening pressure is reached, the valve needle 15 becomes counter to the action of the closing spring 27, which loads the valve needle 15 indirectly via the piston 30 , lifted off the valve seat 16; injection begins. With increasing pressure, the valve needle 15 continues to lift off the valve seat 16 and thereby moves the piston 30 until its control edge 36, after a preliminary stroke h, the v
Verbindung der Druckkammer 33 mit der Federkammer 26 unterbricht. Während dieser Vorhubphase verdrängt die Ventilnadel 15 aufgrund ihres großen Durchmessers mehr Kraftstoffvolumen in der Druckkammer 33 als durch unmittelbares Verschieben des Kolbens 30 frei wird, der einen kleineren Durchmesser hat. Das Differenzvolumen wird dabei aus der Druckkammer 33 durch die L ngsnut 35 im Kolben 30 in die druck¬ entlastete Federkammer 36 verdrängt. Die Schließfeder 27 wird wäh¬ rend dieser Vorhubphase mit einer Kraft gespannt, die sich aus dem ansteigenden Kraftstoffzuführdruck in Verbindung mit der Wirkfläche der Ventilnadel 15 unter Vernachlässigung der Reibungsverluste er¬ gibt. Am Ende des Vorhubs h , wenn die Steuerkante 36 des Kolbens vInterruption of the pressure chamber 33 with the spring chamber 26. During this preliminary stroke phase, the valve needle 15 displaces more fuel volume in the pressure chamber 33 due to its large diameter than is released by directly displacing the piston 30, which has a smaller diameter. The differential volume is displaced from the pressure chamber 33 through the longitudinal groove 35 in the piston 30 into the pressure-relieved spring chamber 36. During this pre-stroke phase, the closing spring 27 is tensioned with a force which results from the increasing fuel supply pressure in connection with the active surface of the valve needle 15, neglecting the frictional losses. At the end of the advance stroke h, when the control edge 36 of the piston v
30 die Druckkammer 33 absperrt, baut sich anschließend unter der Pumpwirkung der Ventilnadel 15, die weiterhin vom steigenden Zuführ- druck beaufschlagt ist, in der Druckkammer 33 ein Steuerdruck auf, der den Kolben 30 beaufschlagt. Dieser Steuerdruck ist, da die Wirk¬ fläche an der Zuführseite der Ventilnadel 15 und die Wirkfläche an der die Druckkammer 33 begrenzenden Seite gleich groß sind, im wesentlichen gleich dem Zuführdruck. Ab dem Zeitpunkt aber, wo die Druckkammer 33 abgesperrt worden ist, verdrängt das von der Ventil¬ nadel 15 verdrängte Volumen den Kolben 30, der von der um den Vorhub h weiter vorgespannten Schließfeder 26 belastet ist. Da aber die Wirkfläche des Kolbens 30 kleiner ist als die der Ventilnadel 15, und damit am Ende des Vorhubs h die vom Kolben 30 erzeugte Kraft kleiner als die von der Ventilnadel 15 erzeugte Kraft ist, die der Schließfederkraft gleich ist, verbleibt der Kolben 30 so lange in Anlage an der Ventilnadel 15, bis der Zuführdruck und damit auch der Steuerdruck in der Druckkammer 33 so weit gestiegen sind, daß die vom Kolben 30 erzeugte Kraft die am Ende des Vorhubs erreichte Vor¬ spannkraft der Schließfeder 27 in der Vorhubstellung übersteigt. Während dieser Zeit verbleibt auch die Ventilnadel 15 in Vorhub- stellung. Erreicht dann der Zuführdruck und damit auch der Steuer¬ druck in der Druckkammer 33 einen Wert, aufgrund dessen der Kolben 30 mit einer Kraft belastet wird, die der der vorgespannten Schlie߬ feder 26 gleichkommt und größer wird, setzt eine hydraulische Hub¬ umsetzung von der Ventilnadel 15 auf den Kolben 30 ein, aufgrund der das Spannen der Schließfeder 27 nun vom Kolben 30 durchgeführt wird. In Abhängigkeit von der Differenz des Durchmessers der Ventilnadel 15 und des Kolbens 30 verschiebt sich nun der Kolben 30 bei weiterem Druckanstieg pro Hubeinheit der Ventilnadel 15 um eine größere Hub¬ einheit. Der Kolben 30 hebt dadurch von der Stirnseite 41 der Ven¬ tilnadel 15 ab und entfernt sich von dieser immer mehr, bis die Ven¬ tilnadel 15 mit ihrer Stirnseite 41, bzw. Schulter 43 nach Durch¬ laufen des Gesamthubes h an der Zwischenscheibe 11 anschlägt. Da, wie oben erwähnt, die Wirkfläche des Kolbens 30 kleiner ist als die der Ventilnadel 15, wird nach Zurücklegen des Vorhubs h der Weg des Kolbens 30 größer als der der Ventilnadel 15. Dies hat zur Fol- ge, daß bei gleicher Federsteifigkeit die vom Kolben 30 über das hy¬ draulische Kissen in der Druckkammer 33 auf die Ventilnadel 15 aus¬ geübte Schließkraft größer wird, die Charakteristik der beschrie¬ benen Einspritzdüse also der eines Zweifederhalters entspricht. 30 shuts off the pressure chamber 33, a control pressure subsequently builds up in the pressure chamber 33 under the pumping action of the valve needle 15, which is still acted upon by the increasing supply pressure, which acts on the piston 30. Since the effective area on the supply side of the valve needle 15 and the effective area on the side delimiting the pressure chamber 33 are of the same size, this control pressure is essentially the same as the supply pressure. However, from the point in time at which the pressure chamber 33 has been shut off, the volume displaced by the valve needle 15 displaces the piston 30, which is loaded by the closing spring 26 which is further biased by the forward stroke h. However, since the effective area of the piston 30 is smaller than that of the valve needle 15, and thus at the end of the advance stroke h the force generated by the piston 30 is smaller than the force generated by the valve needle 15, which is the same as the closing spring force, the piston 30 remains so long in contact with the valve needle 15 until the supply pressure and thus also the control pressure in the pressure chamber 33 have risen so far that the force generated by the piston 30 exceeds the pretensioning force of the closing spring 27 reached at the end of the forward stroke in the preliminary stroke position. During this time, the valve needle 15 also remains in the pre-stroke position. If the supply pressure and thus also the control pressure in the pressure chamber 33 then reach a value on the basis of which the piston 30 is loaded with a force which is equal to and greater than that of the prestressed closing spring 26, a hydraulic stroke conversion of the Valve needle 15 on the piston 30, due to which the tensioning of the closing spring 27 is now carried out by the piston 30. Depending on the difference in the diameter of the valve needle 15 and the piston 30, the piston 30 is now displaced by a larger stroke unit as the pressure increases per stroke unit of the valve needle 15. As a result, the piston 30 lifts off the end face 41 of the valve needle 15 and moves away from it until the valve needle 15 strikes the intermediate disk 11 with its end face 41 or shoulder 43 after passing through the total stroke h . Since, as mentioned above, the effective area of the piston 30 is smaller than that of the valve needle 15, the travel of the piston 30 becomes greater than that of the valve needle 15 after the advance stroke h has been covered. ge that the closing force exerted by the piston 30 via the hydraulic cushion in the pressure chamber 33 on the valve needle 15 increases with the same spring stiffness, the characteristic of the described injector thus corresponds to that of a two-spring holder.

Claims

Ansprüche Expectations
1. Kraftstoff-Einspritzdüse für Brennkraftmaschinen mit einem Düsen¬ körper, in dem eine nach innen öffnende Ventilnadel verschiebbar ge¬ lagert ist, mit einem den Düsenkörper über eine Zwischenwand tragen¬ den Haltekörper, in welchem eine Kammer zur Aufnahme einer die Ven¬ tilnadel im Schließsinn belastende Schließfeder gebildet ist, und mit einer die Zwischenwand durchsetzenden, die Kraft der Schlie߬ feder auf die Ventilnadel übertragenden Kraftübertragungseinrich¬ tung, welche einen einen Druckraum begrenzenden Kolben aufweist, dessen hydraulische Wirkfläche kleiner ist als die der Ventilnadel, dadurch gekennzeichnet, daß die Ventilnadel (15) mit ihrer der Ven¬ tilseite entgegengesezten Seite den Druckraum (33) begrenzt, daß der Kolben (30) einerseits den Druckraum (33) zur Ventilnadel (15) hin begrenzt und andererseits von der Schließfeder (27) belastet ist, daß der Kolben (30) eine eine Verbindung zu einer druckentlasteten Seite (26) und der Druckkammer (33) steuernde Steuerkante (36) auf¬ weist, über welche in der Schließstellung und während des Vorhubs der Ventilnadel (15), während dessen der Kolben (30) unter der Kraft der Schließfeder (27) gegen die Ventilnadel (15) gedrückt wird, eine Verbindung zwischen der Druckkammer (33) und der druckentlasteten Seite (26) besteht und diese Verbindung nach Zurücklegen des Vorhubs1. Fuel injection nozzle for internal combustion engines with a nozzle body, in which an inwardly opening valve needle is slidably supported, with a holding body carrying the nozzle body via an intermediate wall, in which a chamber for receiving a valve needle in the Closing spring which loads the sense of closing is formed, and with a force transmission device which passes through the intermediate wall and transmits the force of the closing spring to the valve needle and has a piston which delimits a pressure chamber and whose hydraulic effective area is smaller than that of the valve needle, characterized in that the Valve needle (15) with its side opposite the valve side limits the pressure chamber (33), that the piston (30) on the one hand delimits the pressure chamber (33) towards the valve needle (15) and on the other hand is loaded by the closing spring (27) that the piston (30) connects to a pressure-relieved side (26) and the pressure chamber (33) controlling control edge (36), via which, in the closed position and during the forward stroke of the valve needle (15), during which the piston (30) is pressed against the valve needle (15) under the force of the closing spring (27) , There is a connection between the pressure chamber (33) and the pressure-relieved side (26) and this connection after the advance stroke
(v.n) beim Resthub der Ventilnadel (15) und des Kolbens 30 unter- brochen wird, so daß der Resthub des Kolbens (30) durch hydraulische Hubumsetzung erfolgt. (vn) is interrupted during the remaining stroke of the valve needle (15) and the piston 30, so that the remaining stroke of the piston (30) takes place by hydraulic stroke conversion.
2. Kraftstoff-Einspritzdüse nach Anspruch 1, dadurch gekennzeichnet, daß die Zwischenwand (11) von einer zwischen dem Düsenkörper (10) und dem Haltekörper (12) eingespannten Zwischenscheibe (11) gebildet ist, und daß die Druckkammer (33) im Bereich der beiden aneinander angrenzenden Endbereiche des Druckkörpers (10) und der Zwischen¬ scheibe (11) liegt.2. Fuel injection nozzle according to claim 1, characterized in that the intermediate wall (11) is formed by an intermediate disc (11) clamped between the nozzle body (10) and the holding body (12), and in that the pressure chamber (33) in the region of two adjoining end regions of the pressure body (10) and the intermediate washer (11).
3. Kraftstoff-Einspritzdüse nach Anspruch 2, dadurch gekennzeichnet, daß die Druckkammer (33) von einer Erweiterung (32) der Führungs¬ bohrung (18) für die Ventilnadel (15) an dem der Zwischenscheibe (11) nahen Ende des Düsenkörpers (10) umfaßt wird.3. Fuel injection nozzle according to claim 2, characterized in that the pressure chamber (33) from an extension (32) of the guide bore (18) for the valve needle (15) on the end of the nozzle body (10) near the intermediate disc (11) ) is included.
4. Kraftstoff-Einspritzdüse nach einem der Ansprüche 1 bis 3, da¬ durch gekennzeichnet, daß sich an die Steuerkante (36) des Kolbens (30) eine in die Federkammer (26) des Haltekörpers (12) führende Längsnut (35) oder Abtragung anschließt.4. Fuel injection nozzle according to one of claims 1 to 3, da¬ characterized in that on the control edge (36) of the piston (30) in the spring chamber (26) of the holding body (12) leading longitudinal groove (35) or removal connects.
5. Kraftstoff-Einspritzdüse nach Anspruch 4, dadurch gekennzeichnet, daß der Kolben (30) an seiner der Ventilnadel (15) zugewandten Stirnseite ballig ausgebildet ist und die gegenüberliegende Stirn¬ seite (41) der Ventilnadel (15) eben ist.5. Fuel injection nozzle according to claim 4, characterized in that the piston (30) on its valve needle (15) facing end face is spherical and the opposite end face (41) of the valve needle (15) is flat.
6. Kraftstoff-Einspritzdüse nach Anspruch 4, dadurch gekennzeichnet, daß der Kolben (30) eine Sackbohrung (45) hat, in die ein Druck¬ zapfen (44) der Ventilnadel (15) eingreift. 6. Fuel injection nozzle according to claim 4, characterized in that the piston (30) has a blind bore (45) into which a pressure pin (44) of the valve needle (15) engages.
EP93915674A 1992-08-05 1993-07-29 Fuel injection nozzle for internal combustion engines Expired - Lifetime EP0606436B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE4225805A DE4225805A1 (en) 1992-08-05 1992-08-05 Fuel injection nozzle for internal combustion engines
DE4225805 1992-08-05
PCT/DE1993/000669 WO1994003720A1 (en) 1992-08-05 1993-07-29 Fuel injection nozzle for internal combustion engines

Publications (2)

Publication Number Publication Date
EP0606436A1 true EP0606436A1 (en) 1994-07-20
EP0606436B1 EP0606436B1 (en) 1996-10-02

Family

ID=6464844

Family Applications (1)

Application Number Title Priority Date Filing Date
EP93915674A Expired - Lifetime EP0606436B1 (en) 1992-08-05 1993-07-29 Fuel injection nozzle for internal combustion engines

Country Status (5)

Country Link
US (1) US5464158A (en)
EP (1) EP0606436B1 (en)
JP (1) JP3433938B2 (en)
DE (2) DE4225805A1 (en)
WO (1) WO1994003720A1 (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4440182C2 (en) * 1994-11-10 2003-09-18 Bosch Gmbh Robert Fuel injection valve for internal combustion engines
US5950931A (en) * 1998-01-30 1999-09-14 Caterpillar Inc. Pressure decay passage for a fuel injector having a trapped volume nozzle assembly
US6543706B1 (en) * 1999-02-26 2003-04-08 Diesel Technology Company Fuel injection nozzle for an internal combustion engine
DE102005054927A1 (en) * 2005-11-17 2007-05-31 Siemens Ag Fuel injector for common rail diesel injection for diesel engine, has nozzle needle which has steps in its shaft and damping chamber is formed in area of steps between shaft of nozzle needle and housing wall
JP5580812B2 (en) 2009-05-15 2014-08-27 株式会社日本触媒 Method for producing (meth) acrylic acid
US9605639B2 (en) 2012-07-12 2017-03-28 Ford Global Technologies, Llc Fuel injector

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3041018C2 (en) * 1980-10-31 1986-03-20 Daimler-Benz Ag, 7000 Stuttgart Fuel injection device for an air-compressing injection internal combustion engine
DE3611316A1 (en) * 1986-04-04 1987-10-08 Bosch Gmbh Robert FUEL INJECTION NOZZLE FOR INTERNAL COMBUSTION ENGINES
EP0404917A1 (en) * 1989-01-12 1991-01-02 VOEST-ALPINE AUTOMOTIVE Gesellschaft m.b.H. Fuel injection nozzle
DE4126698A1 (en) * 1991-08-13 1992-10-15 Daimler Benz Ag Fuel injection nozzle for IC engine - has two flow connections between spring and damper chambers, for alternately dampened/non-dampener opening stroke

Non-Patent Citations (1)

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Title
See references of WO9403720A1 *

Also Published As

Publication number Publication date
DE4225805A1 (en) 1994-02-10
JPH07502585A (en) 1995-03-16
WO1994003720A1 (en) 1994-02-17
EP0606436B1 (en) 1996-10-02
US5464158A (en) 1995-11-07
JP3433938B2 (en) 2003-08-04
DE59304048D1 (en) 1996-11-07

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