EP0128161B1 - Fuel nozzle for internal combustion engines - Google Patents

Fuel nozzle for internal combustion engines Download PDF

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Publication number
EP0128161B1
EP0128161B1 EP83903782A EP83903782A EP0128161B1 EP 0128161 B1 EP0128161 B1 EP 0128161B1 EP 83903782 A EP83903782 A EP 83903782A EP 83903782 A EP83903782 A EP 83903782A EP 0128161 B1 EP0128161 B1 EP 0128161B1
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EP
European Patent Office
Prior art keywords
cap
valve needle
throttle channel
plunger
stroke
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
Application number
EP83903782A
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German (de)
French (fr)
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EP0128161A1 (en
Inventor
Iwan Komaroff
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
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Robert Bosch GmbH
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Publication date
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Publication of EP0128161A1 publication Critical patent/EP0128161A1/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
    • 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
    • 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
    • F02M61/08—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 the valves opening in direction of fuel flow

Definitions

  • the invention relates to a fuel injector for internal combustion engines according to the preamble of the main claim.
  • the opening movement of the valve needle is delayed or damped at least over a partial stroke in that the fuel is throttled only in the can flow into the damping chamber.
  • the closing stroke of the valve needle it is ensured that the valve needle can quickly return to its closed position without being impeded by the damping means.
  • the cap forming the damping space is centered in the radial direction directly on the piston, so that a sufficiently large radial play is provided between the cap and the surrounding walls of the nozzle holder and thereby jamming of the parts can be avoided with certainty.
  • the piston can be formed by the valve needle itself or by its end section facing away from the spray opening. Due to the cap integrated in the volume of the pressure chamber, a displacement of the volume by piston action which influences the flow is avoided.
  • the passage cross section of the throttle channel remains completely or almost completely the same in some embodiments of the unpublished EP-A-0 084 662 over the entire first partial stroke of the valve needle, which in some applications leads to the throttle channel designed for the lower idling operating point increasing in speed and increasing valve needle stroke throttles more than desired and inhibits the valve needle during its opening movement.
  • a valve is provided on the cap, which opens an additional throttle duct leading into the damping space when the pressure difference between the main flow path of the fuel and the damping space exceeds a predetermined value .
  • a damping piston is provided upstream of the valve needle, which is supported on the housing stroke during its opening stroke and acts on the closing spring force on one is displaceably mounted on the pressure pin transmitting the valve needle and, together with the facing end face of the valve needle, delimits a damping space which is connected to the closing spring chamber via a throttle opening.
  • the arrangement according to the invention with the characterizing features of the main claim has the advantage over an embodiment of the generic type that the throttling action has a yielding course already during the first partial stroke of the valve needle, so that the throttling becomes weaker overall with increasing speed of the internal combustion engine and increasing valve needle stroke.
  • the intensity of the increase in cross section of the throttle channel up to the highest speed of the internal combustion engine can be matched to the requirements of the respective application by appropriate geometric design of the throttle channel or the part controlling the throttle channel.
  • the throttle duct is formed by at least one opening in the jacket wall of the cap, which is at least partially covered by the piston in the closed position of the valve needle.
  • the piston itself controls the passage cross section of the throttle channel.
  • a progressive decrease in the throttling effect can be achieved by arranging the features listed in claims 3 to 6.
  • the invention further proposes. that in addition to the throttle channel controlled by the piston or by a part connected to the piston, at least one further additional throttle channel is provided with an unchanging passage cross section.
  • the controlled throttle channel can also be completely closed in the closed position of the valve needle.
  • the additional throttle duct with the unchangeable passage cross-section can advantageously be formed by a fine bore in a perforated brick, which is inserted, for example, in the bottom of the cap and consists of synthetic sapphire. Such a bore can be produced using known manufacturing methods with the smallest manufacturing tolerances.
  • the controlled throttle channel can also be formed in a perforated brick made of synthetic sapphire, which, for example, also sits in the bottom of the cap and in whose bore a throttle pin molded onto the piston projects.
  • the arrangement according to the invention of the throttle connection between the damping space and the flow path of the fuel can advantageously also be combined with the measure that the cap enclosing the damping space receives a forward stroke and a support point on the valve needle or the piston.
  • the pre-stroke serves for the rapid injection of the initial quantity and in cooperation with the support for damping the needle bouncer when the valve needle is closed.
  • the mass of the damping cylinder can be varied to match the bouncer damping properties.
  • FIG. 1 shows a longitudinal section through the first exemplary embodiment
  • FIG. 2 enlarges the damping means of the injection nozzle according to FIG. 1
  • FIG. 3 shows a side view of the damping means in the direction of arrow A in FIG. 2
  • FIG. 4 shows a representation of the second one corresponding to FIG. 3 Embodiment and in Figure 5, the damping means of an injection nozzle according to the third embodiment are shown.
  • the injection nozzle according to FIGS. 1 to 3 has a nozzle body 10 which is clamped to a nozzle holder 14 by a union nut 12.
  • a sleeve 16 Arranged between the nozzle body 10 and the nozzle holder 14 is a sleeve 16 which has an inwardly directed shoulder 18 which divides a chamber 20 from a chamber 22 of larger diameter inside the injection nozzle.
  • a valve seat 24 is formed in the nozzle body 10 and a valve needle 26 is displaceably mounted, the sealing cone 27 of which is pressed against the valve seat 24 by a closing spring 28.
  • the closing spring 28 is supported on the nozzle body 10 and engages via a flange part 30 on a support disk 32, which in turn is supported on a shoulder 34 of the valve needle 26.
  • an inlet bore 36 is formed, which opens into the chamber 20, which is connected to the chamber 22 via an opening 38 surrounded by the shoulder 18. From this, a bore 40 in the nozzle body 10 leads into an annular space 42, which is formed between the central bore wall of the nozzle body 10 and the circumference of a section 44 of the valve needle 26 with a reduced diameter and extends directly up to the valve seat 24. Between the flange part 30 and the nozzle body 10 there is a distance hg in the closed position shown, which corresponds to the total stroke of the valve needle 26. The valve needle 26 is displaced outward in the opening direction by the fuel pressure against the closing spring 28 until the flange part 30 strikes the nozzle body 10. When the valve closes, the closing spring 28 returns the valve needle 26 inwards to the closed position shown.
  • a piston-shaped extension 46 adjoins the shoulder 34 of the valve needle 26, which extends through the opening 38 and projects into the chamber 20.
  • the diameter of the piston-shaped projection 46 corresponds to the guide diameter of the valve needle 26.
  • a cap 48 is placed on the projection 46, which has a bottom 50, a jacket part 52 and a flange edge 54.
  • a return spring 56 engages on the cap 48, which surrounds the jacket part 52 and presses the flange edge 54 against the shoulder 18 of the sleeve 16.
  • transverse slots 58 are provided through which the fuel can pass from the chamber 20 into the chamber 22.
  • a damping space 60 is formed in the cap 48 between the end face of the shoulder 46 and the base 50, which is continuously connected to the chamber 20 via a throttle channel 62 in the base 50.
  • the throttle channel 62 is formed by the central bore of a perforated brick 64, which consists of synthetic sapphire and is firmly glued or pressed into the bottom 50.
  • the piston-shaped extension 46 covers the transverse slots 58 in the cap 48 in the axial direction by the path h v , which corresponds to the damped forward stroke of the valve needle 26 described below. Furthermore, the opening 66 is completely covered by the extension 46 in the closed position.
  • the cap 48 is taken upward via the inflated fuel cushion in the damping space 60, the return spring 56 opposing the substantially stronger closing spring 28 only with a relatively low resistance.
  • the return spring 56 can be dimensioned with regard to rigidity and preload so that the fuel quantity flowing into the damping space 60 is pushed out of the damping space 60 from the beginning of the closing stroke of the valve needle 26 to the beginning of the next opening stroke either up to the initial or a certain residual volume becomes.
  • the cap 48 either comes back into contact with the shoulder 18 or remains, depending on the speed, an amount away from the shoulder 18, which influences the damping characteristics and the adaptation thereof gives further flexibility.
  • the cap 48 is centered on the valve needle 26 and has a sufficiently large radial play with respect to the nozzle holder 14 so that the valve needle 26 can work without jamming.
  • the return spring 56 for the cap 48 extends partially over the cap 48, so that in this embodiment the means for partially damping the opening stroke of the valve needle 26 take up little space in the axial direction of the injection nozzle.
  • the cap 48 is provided with parallel longitudinal slots 68, 69, the ends of which face the bottom 50 of the cap are offset with respect to one another in the axial direction.
  • the longitudinal slots 68, 69 together form the controlled throttle channel; they are controlled one after the other by the piston-shaped extension 46 during the opening stroke of the valve needle 26, which results in the desired cross-sectional profile over the valve needle stroke.
  • the longitudinal slots 68, 69 lie in the region of local depressions 70, which are provided on the outside in the casing part 52 of the cap 48.
  • the cap 48 is instead of openings 66 in the jacket part 52 with a larger bore 72 in the.
  • a pin 74 of the piston-shaped projection 46 of the valve needle 26 protrudes.
  • the pin 74 is profiled in such a way that an initial section 76 with a larger diameter and an end section 78 with a smaller diameter result.

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

Abstract

Fuel nozzle for internal combustion engines, with a valve needle (26) opening outwardly, connected to a piston (46) delimiting a vaporization chamber (60) filled with fuel and connected upon the first partial rise of the valve needle (26) to the fuel flow path only by a throttle connection. The vaporization chamber (60) is formed within a cap (48) arranged on the piston (46) and centered thereto. The throttle connection is comprised of at least one throttle channel (66, 68, 69, 72) of which the passage cross-section, contrary to embodiments of the main patent application, is modified as a function of the rise of the valve needle (26). The original cross-section of the throttle connection may thereby be limited to a very small value, without the throttling having negative effects upon the increase of the rotation speed and rises of the needle. In certain applications, the original throttling cross-section may be conveniently determined by a fixedly regulated shutter (62).

Description

Die Erfindung geht aus von einer Kraftstoff-Einspritzdüse für Brennkraftmaschinen nach der Gattung des Hauptanspruchs. Bei den Einspritzdüsen dieser Gattung (EP-A-0 084 662, Stand der Technik nach Art 54 (3) des EPÜ) wird die Öffnungsbewegung der Ventilnadel zumindest über einen Teilhub hinweg dadurch verzögert bzw. gedämpft, daß der Kraftstoff nur gedrosselt in den sich dabei vergrößernden Dämpfungsraum nachströmen kann. Beim Schließhub der Ventilnadel ist dafür gesorgt, daß die Ventilnadel ohne Behinderung durch die Dämpfungsmittel rasch in ihre Schließstellung zurückkehren kann. Die den Dämpfungsraum bildende Kappe ist in radialer Richtung unmittelbar am Kolben zentriert, so daß zwischen der Kappe und den sich umgebenden Wänden des Düsenhalters ein genügend großes radiales Spiel vorgesehen und dadurch ein Klemmen der Teile mit Sicherheit vermieden werden kann. Der Kolben kann durch die Ventilnadel selbst bzw. durch deren von der Spritzöffnung abgekehrten Endabschnitt gebildet sein. Durch die im Volumen des Druckraumes integrierte Kappe wird eine den Förderstrom beeinflußende Volumenverdrängung durch Kolbenwirkung vermieden. Der Durchgangsquerschnitt des Drosselkanals bleibt bei einigen Ausführungsbeispielen der nicht vorveröffentlichten EP-A-0 084 662 über den gesamten ersten Teilhub der Ventilnadel vollständig oder nahezu vollständig gleich, was in manchen Anwendungsfällen dazu führt, daß der für den unteren Leerlauf-Betriebspunkt ausgelegte Drosselkanal bei Drehzahlanstieg und zunehmendem Ventilnadelhub stärker als erwünscht drosselt und die Ventilnadel bei ihrer Öffnungsbewegung hemmt. Bei anderen Ausführungsbeispielen (Figuren 6 und 7 der EP-A-0 084 662) ist ein Ventil an der Kappe vorgesehen, welches einen in den Dämpfungsraum führenden zusätzlichen Drosselkanal öffnet, wenn die Druckdifferenz zwischen dem Hauptströmungsweg des Kraftstoffs und dem Dämpfungsraum einen vorgegebenen Wert überschreitet. Dadurch läßt sich zwar im oberen Leistungsbereich die Drossel- bzw. Dämpfungswirkung begrenzen, jedoch wird durch die Anordnung eines Ventils an der Kappe der Fertigungsaufwand nicht unbeträchtlich erhöht.The invention relates to a fuel injector for internal combustion engines according to the preamble of the main claim. In the case of the injection nozzles of this type (EP-A-0 084 662, prior art according to Art 54 (3) of the EPC), the opening movement of the valve needle is delayed or damped at least over a partial stroke in that the fuel is throttled only in the can flow into the damping chamber. During the closing stroke of the valve needle, it is ensured that the valve needle can quickly return to its closed position without being impeded by the damping means. The cap forming the damping space is centered in the radial direction directly on the piston, so that a sufficiently large radial play is provided between the cap and the surrounding walls of the nozzle holder and thereby jamming of the parts can be avoided with certainty. The piston can be formed by the valve needle itself or by its end section facing away from the spray opening. Due to the cap integrated in the volume of the pressure chamber, a displacement of the volume by piston action which influences the flow is avoided. The passage cross section of the throttle channel remains completely or almost completely the same in some embodiments of the unpublished EP-A-0 084 662 over the entire first partial stroke of the valve needle, which in some applications leads to the throttle channel designed for the lower idling operating point increasing in speed and increasing valve needle stroke throttles more than desired and inhibits the valve needle during its opening movement. In other exemplary embodiments (FIGS. 6 and 7 of EP-A-0 084 662), a valve is provided on the cap, which opens an additional throttle duct leading into the damping space when the pressure difference between the main flow path of the fuel and the damping space exceeds a predetermined value . As a result, the throttling or damping effect can be limited in the upper performance range, but the arrangement of a valve on the cap does not inconsiderably increase the manufacturing outlay.

Bei einer bekannten Einspritzdüse mit einer nach innen öffnenden Ventilnadel und mit Mittelnzum Dämpfen mindestens eines Teils des Öffnungshubes der Ventilnadel (FR-A-2 307 976) ist ein stromauf der Ventilnadel angeordneter, bei deren Öffnungshub gehäusefest abgestützer Dämpfungskolben vorgesehen, der auf einem die Schließfederkraft auf die Ventilnadel übertragenden Druckbolzen verschiebbar gelagert ist und zusammen mit der zugekehrten Stirnseite der Ventilnadel einen Dämpfungsraum begrenzt, der über eine Drosselöffnung mit der Schließfederkammer verbunden ist. Bei dieser Anordnung wird beim Öffnungshub das Kraftstoffpolster aus dem Dämpfungsraum über die Drosselöffung in die Schließfederkammer bzw. in eine Leckölabführung hinein verdrängt. Diese Ausführung läßt sich nicht ohne weiteres auf Einspritzdüsen der gattungsmäßigen Art übertragen.In a known injection nozzle with an inwardly opening valve needle and with means for damping at least a part of the opening stroke of the valve needle (FR-A-2 307 976), a damping piston is provided upstream of the valve needle, which is supported on the housing stroke during its opening stroke and acts on the closing spring force on one is displaceably mounted on the pressure pin transmitting the valve needle and, together with the facing end face of the valve needle, delimits a damping space which is connected to the closing spring chamber via a throttle opening. With this arrangement, the fuel cushion is displaced from the damping chamber via the throttle opening into the closing spring chamber or into a leakage oil drain during the opening stroke. This version can not be easily transferred to injectors of the generic type.

Vorteile der ErfindungAdvantages of the invention

Die erfindungsgemäße Anordnung mit den kennzeichnenden Merkmalen des Hauptanspruchs hat gegenüber einer Ausführung der gattungsmäßigen Art den Vorteil, daß die Drosselwirkung bereits während des ersten Teilhubes der Ventilnadel einen nachgebenden Verlauf hat, so daß mit steigender Drehzahl der Brennkraftmaschine und zunehmendem Ventilnadelhub die Drosselung insgesamt schwächer wird. Durch entsprechende geometrische Gestaltung des Drosselkanals bzw. des den Drosselkanal steuernden Teils kann die Intensität der Querschnittszunahme des Drosselkanals bis zur höchsten Drehzahl der Brennkraftmaschine auf die Erfordernisse des jeweiligen Anwendungsfalles abgestimmt werden.The arrangement according to the invention with the characterizing features of the main claim has the advantage over an embodiment of the generic type that the throttling action has a yielding course already during the first partial stroke of the valve needle, so that the throttling becomes weaker overall with increasing speed of the internal combustion engine and increasing valve needle stroke. The intensity of the increase in cross section of the throttle channel up to the highest speed of the internal combustion engine can be matched to the requirements of the respective application by appropriate geometric design of the throttle channel or the part controlling the throttle channel.

Durch die in den Unteransprüchen aufgeführten Maßnahmen sind vorteilhafte Weiterbildungen der im Hauptanspruch angegebenen Anordnung möglich.Advantageous developments of the arrangement specified in the main claim are possible through the measures listed in the subclaims.

Eine einfache Ausführung ergibt sich, wenn der Drosselkanal von mindestens einem Durchbruch in der Mantelwand der Kappe gebildet ist, welcher durch den Kolben in Schließlage der Ventilnadel mindestens teilweise überdeckt ist. In diesem Fall steuert der Kolben selbst den Durchgangsquerschnitt des Drosselkanals.A simple design results if the throttle duct is formed by at least one opening in the jacket wall of the cap, which is at least partially covered by the piston in the closed position of the valve needle. In this case, the piston itself controls the passage cross section of the throttle channel.

Eine progressive Abnahme der Drosselwirkung läßt sich durch Anordnung der in den Ansprüchen 3 bis 6 aufgeführten Merkmale erreichen.A progressive decrease in the throttling effect can be achieved by arranging the features listed in claims 3 to 6.

Zur exakten Bestimmung der Anfangsdrosselung wird erfindungsgemäß weiter vorgeschlagen. daß außer dem vom Kolben bzw. von einem mit dem Kolben verbundenen Teil gesteuerten Drosselkanal mindestens ein weiterer zusätzlicher Drosselkanal mit unveränderlichem Durchgangsquerschnitt vorgesehen ist. In diesem Falle kann der gesteuerte Drosselkanal in Schließstellung der Ventilnadel auch vollkommen geschlossen sein. Der zusätzliche Drosselkanal mit dem unveränderlichen Durchgangsquerschnitt kann vorteilhaft durch eine Feinstbohrung in einem Lochstein gebildet sein, der beispielsweise in den Boden der Kappe eingesetzt ist und aus synthetischem Saphir besteht. Eine solche Bohrung kann mit bekannten Fertigungsmethoden mit kleinsten Fertigungstoleranzen hergestellt werden.For the exact determination of the initial throttling, the invention further proposes. that in addition to the throttle channel controlled by the piston or by a part connected to the piston, at least one further additional throttle channel is provided with an unchanging passage cross section. In this case, the controlled throttle channel can also be completely closed in the closed position of the valve needle. The additional throttle duct with the unchangeable passage cross-section can advantageously be formed by a fine bore in a perforated brick, which is inserted, for example, in the bottom of the cap and consists of synthetic sapphire. Such a bore can be produced using known manufacturing methods with the smallest manufacturing tolerances.

Auch kann der gesteuerte Drosselkanal in einem Lochstein aus synthetischem Saphir gebildet sein, welcher beispielsweise ebenfalls im Boden der Kappe sitzt und in dessen Bohrung ein am Kolben angeformter Drosselzapfen ragt.The controlled throttle channel can also be formed in a perforated brick made of synthetic sapphire, which, for example, also sits in the bottom of the cap and in whose bore a throttle pin molded onto the piston projects.

Die erfindungsgemäße Anordnung der Drosselverbindung zwischen Dämpfungsraum und Strömungsweg des Kraftstoffs kann vorteilhaft auch mit der Maßnahme kombiniert werden, daß die den Dämpfungsraum umschließende Kappe einen Vorhub und einen Abstützpunkt auf der Ventilnadel bzw. den Kolben erhält. Der Vorhub dient zur schnellen Einspritzung der Anfangsmenge und zusammenwirkend mit der Abstützung zur Dämpfung der Nadelpreller beim Schließen der Ventilnadel. Zur Abstimmung der Prellerdämpfungseigenschaften kann die Masse des Dämpfungszylinders variiert werden.The arrangement according to the invention of the throttle connection between the damping space and the flow path of the fuel can advantageously also be combined with the measure that the cap enclosing the damping space receives a forward stroke and a support point on the valve needle or the piston. The pre-stroke serves for the rapid injection of the initial quantity and in cooperation with the support for damping the needle bouncer when the valve needle is closed. The mass of the damping cylinder can be varied to match the bouncer damping properties.

Zeichnungdrawing

Drei Ausführungsbeispiele der Erfindung sind in der Zeichnung dargestellt und in der nachfolgenden Beschreibung erläutert. Es zeigen Figur 1 einen Längsschnitt durch das erste Ausführungsbeispiel, Figur 2 vergrößert die Dämpfungsmittel der Einspritzdüse nach Figur 1, und Figur 3 eine Seitenansicht der Dämpfungsmittel in Richtung des Pfeiles A in Figur 2 gesehen, Figur 4 zeigt eine der Figur 3 entsprechende Darstellung des zweiten Ausführungsbeispiels und in Figur 5 sind die Dämpfungsmittel einer Einspritzdüse nach dem dritten Ausführungsbeispiel dargestellt.Three embodiments of the invention are shown in the drawing and explained in the following description. FIG. 1 shows a longitudinal section through the first exemplary embodiment, FIG. 2 enlarges the damping means of the injection nozzle according to FIG. 1, and FIG. 3 shows a side view of the damping means in the direction of arrow A in FIG. 2, FIG. 4 shows a representation of the second one corresponding to FIG. 3 Embodiment and in Figure 5, the damping means of an injection nozzle according to the third embodiment are shown.

Beschreibung der AusführungsbeispieleDescription of the embodiments

Die Einspritzdüse nach den Figuren 1 bis 3 hat einen Düsenkörper 10, der durch eine Überwurfmutter 12 an einem Düsenhalter 14 festgespannt ist. Zwischen dem Düsenkörper 10 und dem Düsenhalter 14 ist eine Hülse 16 angeordnet, welche eine nach innen gerichtete Schulter 18 hat, die eine Kammer 20 von einer im Durchmesser größeren Kammer 22 im Inneren der Einspritzdüse abteilt. Im Düsenkörper 10 ist ein Ventilsitz 24 gebildet und eine Ventilnadel 26 verschiebbar gelagert, deren Dichtkegel 27 von einer Schließfeder 28 gegen den Ventilsitz 24 gedrückt ist. Die Schließfeder 28 stützt sich am Düsenkörper 10 ab und greift über ein Flanschteil 30 an einer Stützscheibe 32 an, die sich ihrerseits an einer Schulter 34 der Ventilnadel 26 abstützt.The injection nozzle according to FIGS. 1 to 3 has a nozzle body 10 which is clamped to a nozzle holder 14 by a union nut 12. Arranged between the nozzle body 10 and the nozzle holder 14 is a sleeve 16 which has an inwardly directed shoulder 18 which divides a chamber 20 from a chamber 22 of larger diameter inside the injection nozzle. A valve seat 24 is formed in the nozzle body 10 and a valve needle 26 is displaceably mounted, the sealing cone 27 of which is pressed against the valve seat 24 by a closing spring 28. The closing spring 28 is supported on the nozzle body 10 and engages via a flange part 30 on a support disk 32, which in turn is supported on a shoulder 34 of the valve needle 26.

Im Düsenhalter 14 ist eine Zulaufbohrung 36 gebildet, welche in die Kammer 20 mündet, die über einen von der Schulter 18 umgebenen Durchbruch 38 mit der Kammer 22 verbunden ist. Aus dieser führt eine Bohrung 40 im Düsenkörper 10 in einen Ringraum 42, der zwischen der zentralen Bohrungswand des Düsenkörpers 10 und dem Mantelumfang eines im Durchmesser verkleinerten Abschnittes 44 der Ventilnadel 26 gebildet ist und unmittelbar bis vor den Ventilsitz 24 reicht. Zwischen dem Flanschteil 30 und dem Düsenkörper 10 ist in der dargestellten Schließlage ein Abstand hg vorhanden, welcher dem Gesamthub der Ventilnadel 26 entspricht. Die Ventilnadel 26 wird vom Kraftstoffdruck entgegen der Schließfeder 28 nach außen in Öffnungsrichtung verschoben, bis der Flanschteil 30 am Düsenkörper 10 anschlägt. Beim Schließen des Ventils führt die Schließfeder 28 die Ventilnadel 26 nach innen in die dargestellte Schließlage zurück.In the nozzle holder 14, an inlet bore 36 is formed, which opens into the chamber 20, which is connected to the chamber 22 via an opening 38 surrounded by the shoulder 18. From this, a bore 40 in the nozzle body 10 leads into an annular space 42, which is formed between the central bore wall of the nozzle body 10 and the circumference of a section 44 of the valve needle 26 with a reduced diameter and extends directly up to the valve seat 24. Between the flange part 30 and the nozzle body 10 there is a distance hg in the closed position shown, which corresponds to the total stroke of the valve needle 26. The valve needle 26 is displaced outward in the opening direction by the fuel pressure against the closing spring 28 until the flange part 30 strikes the nozzle body 10. When the valve closes, the closing spring 28 returns the valve needle 26 inwards to the closed position shown.

An die Schulter 34 der Ventilnadel 26 schließt sich ein kolbenförmiger Ansatz 46 an, welcher durch den Durchbruch 38 hindurchtritt und in die Kammer 20 ragt. Der Durchmesser des kolbenförmigen Ansatzes 46 entspricht dem Führungsdurchmesser der Ventilnadel 26. Auf den Ansatz 46 ist eine Kappe 48 aufgesetzt, welche einen Boden 50, einen Mantelteil 52 und einen Flanschrand 54 hat. An der Kappe 48 greift eine Rückholfeder 56 an, welche den Mantelteil 52 umgibt und den Flanschrand 54 gegen die Schulter 18 der Hülse 16 drückt.A piston-shaped extension 46 adjoins the shoulder 34 of the valve needle 26, which extends through the opening 38 and projects into the chamber 20. The diameter of the piston-shaped projection 46 corresponds to the guide diameter of the valve needle 26. A cap 48 is placed on the projection 46, which has a bottom 50, a jacket part 52 and a flange edge 54. A return spring 56 engages on the cap 48, which surrounds the jacket part 52 and presses the flange edge 54 against the shoulder 18 of the sleeve 16.

Im Flanschrand 54 und einem daran anschließenden Bereich des Mantelteils 52 der Kappe 48 sind Querschlitze 58 vorgesehen, durch welche der Kraftstoff aus der Kammer 20 in die Kammer 22 übertreten kann. In der dargestellten Schließlage der Ventilnadel 26 ist zwischen der Stirnseite des Ansatzes 46 und dem Boden 50 in der Kappe 48 ein Dämpfungsraum 60 gebildet, welcher über einen Drosselkanal 62 im Boden 50 mit der Kammer 20 ständig verbunden ist. Der Drosselkanal 62 ist durch die zentrale Bohrung eines Lochsteins 64 gebildet, welcher aus synthetischem Saphir besteht und in den Boden 50 fest eingeklebt oder eingepreßt ist. Im Mantelteil 52 ist ferner ein schmaler, im Querschnitt trapezförmiger Durchbruch 66 vorgesehen, dessen Querschnittsprofil sich zum Flanschrand 54 hin erweitert und welcher in den einen Querschlitz 58 einmündet. In der dargestellten Schließlage überdeckt der kolbenförmige Ansatz 46 die Querschlitze 58 in der Kappe 48 in axialer Richtung um den Weg hv, welcher dem nachstehend beschriebenen gedämpften Vorhub der Ventilnadel 26 entspricht. Ferner ist in der Schließlage der Durchbruch 66 durch den Ansatz 46 vollständig abgedeckt.In the flange edge 54 and an adjoining region of the jacket part 52 of the cap 48, transverse slots 58 are provided through which the fuel can pass from the chamber 20 into the chamber 22. In the illustrated closed position of the valve needle 26, a damping space 60 is formed in the cap 48 between the end face of the shoulder 46 and the base 50, which is continuously connected to the chamber 20 via a throttle channel 62 in the base 50. The throttle channel 62 is formed by the central bore of a perforated brick 64, which consists of synthetic sapphire and is firmly glued or pressed into the bottom 50. In the casing part 52 there is also a narrow opening 66 with a trapezoidal cross section, the cross-sectional profile of which widens towards the flange edge 54 and which opens into a transverse slot 58. In the closed position shown, the piston-shaped extension 46 covers the transverse slots 58 in the cap 48 in the axial direction by the path h v , which corresponds to the damped forward stroke of the valve needle 26 described below. Furthermore, the opening 66 is completely covered by the extension 46 in the closed position.

Die dargestellte Einspritzdüse arbeitet wie folgt :

  • Am Beginn des Öffnungshubes der Ventilnadel 26 ist der Dämpfungsraum 60 nur über den Drosselkanal 62 mit der Kammer 20 und dem Strömungsweg des Kraftstoffs verbunden. Die Kappe 48 kann der Öffnungsbewegung der Ventilnadel 26 nicht folgen, so daß eine Druckdifferenz zwischen dem Dämpfungsraum 60 und der Kammer 20 entsteht, welche die Bewegung der Ventilnadel 26 verzögert bzw. dämpft. Sobald die Ventilnadel 26 ein kleines Wegstück zurückgelegt hat, beginnt der Ansatz 46 den Durchbruch 66 aufzusteuern, wonach eine weitere, zunächst ebenfalls noch gedrosselte Verbindung des Dämpfungsraumes 60 mit der Kammer 20 geschaffen und die Dämpfungskraft gemindert wird. Mit zunehmendem Ventilnadelhub wird der aufgesteuerte Querschnitt des Durchbruchs 66 progressiv größer und dadurch die Dämpfungswirkung auf die Ventilnadel 26 entsprechend geringer. Wenn die Ventilnadel 26 den Weg hv zurückgelegt hat, ist die Stirnseite des Ansatzes 46 an den Beginn der breiteren Querschlitze 58 gelangt. Von dort ab erfolgt der Resthub der Ventilnadel ungedämpft, bis das Flanschteil 30 nach dem Gesamthub hg am Düsenkörper 10 anschlägt.
The injector shown works as follows:
  • At the beginning of the opening stroke of the valve needle 26, the damping chamber 60 is connected to the chamber 20 and the flow path of the fuel only via the throttle channel 62. The cap 48 cannot follow the opening movement of the valve needle 26, so that there is a pressure difference between the damping space 60 and the chamber 20, which delays or dampens the movement of the valve needle 26. As soon as the valve needle 26 has covered a small distance, the projection 46 begins to open the opening 66, after which a further, initially also throttled connection of the damping chamber 60 to the chamber 20 is created and the damping force is reduced. As the valve needle stroke increases, the open cross-section of the opening 66 becomes progressively larger and the damping effect on the valve needle 26 is correspondingly smaller. When the valve needle 26 has traveled the path h v , the end face of the extension 46 is at the beginning of the wider transverse slots 58 reached. From there, the remaining stroke of the valve needle takes place without damping until the flange part 30 strikes the nozzle body 10 after the total stroke hg.

Beim ersten Teilhub hv wird Kraftstoff durch den Drosselkanal 62 und den Durchbruch 66 in den Dämpfungsraum 60 eingedrückt. Bei der Schließbewegung der Ventilnadel 26 wird über das eingeströmte Kraftstoffpolster im Dämpfungsraum 60 die Kappe 48 mit nach oben genommen, wobei die Rückführfeder 56 der wesentlich stärkeren Schließfeder 28 nur einen verhältnismäßig geringen Widerstand entgegensetzt. Die Rückführfeder 56 kann im Hinblick auf Steifigkeit und Vorspannung so bemessen werden, daß die in den Dämpfungsraum 60 eingeströmte Kraftstoffmenge vom Beginn des Schließhubes der Ventilnadel 26 bis zum Beginn des nächsten Öffnungshubes entweder bis auf das Anfangs-oder ein bestimmtes Restvolumen aus dem Dämpfungsraum 60 herausgedrückt wird. Die Kappe 48 kommt dabei entweder wieder zur Anlage an der Schulter 18 oder bleibt drehzahlabhängig um einen Betrag von der Schulter 18 entfernt, was die Dämpfungscharakteristik beeinflußt und deren Anpassung weitere Flexibilität verleiht.During the first partial stroke h v , fuel is pressed into the damping chamber 60 through the throttle duct 62 and the opening 66. During the closing movement of the valve needle 26, the cap 48 is taken upward via the inflated fuel cushion in the damping space 60, the return spring 56 opposing the substantially stronger closing spring 28 only with a relatively low resistance. The return spring 56 can be dimensioned with regard to rigidity and preload so that the fuel quantity flowing into the damping space 60 is pushed out of the damping space 60 from the beginning of the closing stroke of the valve needle 26 to the beginning of the next opening stroke either up to the initial or a certain residual volume becomes. The cap 48 either comes back into contact with the shoulder 18 or remains, depending on the speed, an amount away from the shoulder 18, which influences the damping characteristics and the adaptation thereof gives further flexibility.

Die Kappe 48 zentriert sich auf der Ventilnadel 26 und hat ein ausreichend großes radiales Spiel gegenüber dem Düsenhalter 14, so daß die Ventilnadel 26 klemmfrei arbeiten kann. Die Rückführfeder 56 für die Kappe 48 erstreckt sich zum Teil über die Kappe 48 hinweg, so daß bei dieser Ausführung die Mittel zum partiellen Dämpfen des Öffnungshubes der Ventilnadel 26 nur wenig Platz in Achsrichtung der Einspritzdüse benötigen.The cap 48 is centered on the valve needle 26 and has a sufficiently large radial play with respect to the nozzle holder 14 so that the valve needle 26 can work without jamming. The return spring 56 for the cap 48 extends partially over the cap 48, so that in this embodiment the means for partially damping the opening stroke of the valve needle 26 take up little space in the axial direction of the injection nozzle.

Beim Ausführungsbeispiel nach Figur4 ist die Kappe 48 anstelle der trapezförmigen Durchbrüche 66 mit parallel am Umfang liegenden Längsschlitzen 68, 69 versehen, deren dem Boden 50 der Kappe zugekehrte Enden in Achsrichtung zueinander versetzt sind. Die Längsschlitze 68, 69 bilden miteinander den gesteuerten Drosselkanal ; sie werden vom kolbenförmigen Ansatz 46 beim Öffnungshub der Ventilnadel 26 zeitlich nacheinander aufgesteuert, wodurch sich der gewünschte Querschnittsverlauf über dem Ventilnadelhub ergibt. Die Längsschlitze 68, 69 liegen aus Fertigungsgründen im Bereich von örtlichen Vertiefungen 70, welche außen im Mantelteil 52 der Kappe 48 vorgesehen sind.In the exemplary embodiment according to FIG. 4, instead of the trapezoidal openings 66, the cap 48 is provided with parallel longitudinal slots 68, 69, the ends of which face the bottom 50 of the cap are offset with respect to one another in the axial direction. The longitudinal slots 68, 69 together form the controlled throttle channel; they are controlled one after the other by the piston-shaped extension 46 during the opening stroke of the valve needle 26, which results in the desired cross-sectional profile over the valve needle stroke. For manufacturing reasons, the longitudinal slots 68, 69 lie in the region of local depressions 70, which are provided on the outside in the casing part 52 of the cap 48.

Beim Ausführungsbeispiel nach Figur 5 ist die Kappe 48 anstelle von Durchbrüchen 66 im Mantelteil 52 mit einer größeren Bohrung 72 im . Boden 50 versehen, in welche ein Zapfen 74 des kolbenförmigen Ansatzes 46 der Ventilnadel 26 hineinragt. Der Zapfen 74 ist in Achsrichtung gesehen derart profiliert, daß sich ein im Durchmesser größerer Anfangsabschnitt 76 und ein im Durchmesser kleinerer Endabschnitt 78 ergibt.In the exemplary embodiment according to FIG. 5, the cap 48 is instead of openings 66 in the jacket part 52 with a larger bore 72 in the. Provided bottom 50, in which a pin 74 of the piston-shaped projection 46 of the valve needle 26 protrudes. When viewed in the axial direction, the pin 74 is profiled in such a way that an initial section 76 with a larger diameter and an end section 78 with a smaller diameter result.

Bei geschlossenem Ventil ragt, wie in Figur 5 dargestellt, der größere Anfangsabschnitt 76 des Zapfens 74 in die Bohrung 72 hinein. Diese Teile sind so aufeinander abgestimmt, daß ein geringer Restspalt 80 erhalten bleibt, über welchen der Dämpfungsraum 60 mit der Kammer 20 (Figur 1) verbunden ist. Im Verlauf des Öffnungshubes der Ventilnadel 26 tritt der Anfangsabschnitt 76 des Zapfens 74 aus der Bohrung 72 aus, wodurch sich wie gewünscht der Querschnitt der Bohrung 72 vergrößert.When the valve is closed, as shown in FIG. 5, the larger initial section 76 of the pin 74 projects into the bore 72. These parts are matched to one another in such a way that a small remaining gap 80 remains, via which the damping space 60 is connected to the chamber 20 (FIG. 1). In the course of the opening stroke of the valve needle 26, the initial section 76 of the pin 74 emerges from the bore 72, as a result of which the cross section of the bore 72 increases as desired.

Claims (8)

1. Fuel injection nozzle for internal combustion engines, with a valve needle (26), which is loaded by a closing spring (28), opens in flow direction of the fuel and is connected to a plunger (46) or itself forms a plunger which, together with a cap (48) fitted on its free end, limits a damping space (60) filled with fuel, which damping space is connected, at least over a section (h & v) of the opening stroke of the valve needle (26), only via a throttle channel (66, 68, 69, 72) arranged in the cap (48) to the main flow path, surrounding the cap (48), of the fuel flowing to the nozzle opening (24, 27), the throttle channel (66, 68, 69, 72) enlarging during the opening stroke of the valve needle (26) and reducing during its closing stroke, furthermore with a stop (18), fixed to the housing, for the cap (48), against which the cap (48) comes into contact during the opening stroke at the latest after an undamped pre-stroke, after which there occurs a relative movement between the cap (48) and the forward-moving plunger (46), enlarging the damping space (60), and furthermore with a return spring (56), which acts on the cap (48) and, during the closing stroke of the valve needle (26) and thereafter, guides the cap (48) back through the throttle channel (66, 68, 69, 72) towards the initial position, with reduction of the damping space (60) and displacement of the fuel, characterized in that the cross-sectional area of passage of the throttle channel (66, 68, 69, 72) is covered and controlled directly by the plunger (46), or by a part rigidly connected to the plunger (46) as a function of the stroke of the valve needle (26).
2. Injection nozzle according to Claim 1, characterized in that the throttle channel is formed by at least one opening (66) in the casing wall (52) of the cap (48), which opening is at least partially covered over by the plunger (46) in the closed position of the valve needle (26).
3. Injection nozzle according to Claim 2, characterized in that the width of the opening (66) measured transversely to the axial direction of the cap (48) and of the plunger (46) increases towards the open end of the cap (48).
4. Injection nozzle according to Claim 2, characterized in that the cap (48) is provided in its casing wall (52) with two longitudinal slots (68, 69), which form the controlled throttle channel and the ends of which facing the bottom (50) of the cap (48) are mutually offset in axial direction.
5. Injection nozzle according to Claim 2, 3 or 4, with a transverse slot (58) in the casing wall (52) of the cap (48), via which the damping space (60) is connected, after a predetermined partial-stroke of the valve needle (26), at least substantially unthrottled to the main flow path of the fuel, characterized in that the openings (66, 68, 69) in the casing wall (52) of the cap (48), forming the throttle channel, open out into the radial slot (58) of the cap.
6. Injection nozzle according to Claim 1, characterized in that the throttle channel is formed by a bore (72) in the bottom (50) of the cap (48), into which enters an extension (74) formed on the plunger (46) or the valve needle (26) and profiled in axial direction.
7. Injection nozzle according to one of the preceding claims, characterized in that, apart from the throttle channel (66) controlled by the plunger (46) or by a part connected to the plunger, at least one other additional throttle channel (62) with unchanging cross-section of passage is provided.
8. Injection nozzle according to Claim 7, characterized in that the additional throttle channel (62) is formed by a precision bore in a perforated block (64) of synthetic sapphire mounted in the bottom (50) of the cap (48).
EP83903782A 1982-12-18 1983-11-22 Fuel nozzle for internal combustion engines Expired EP0128161B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19823246916 DE3246916A1 (en) 1982-12-18 1982-12-18 FUEL INJECTION NOZZLE FOR INTERNAL COMBUSTION ENGINES
DE3246916 1982-12-18

Publications (2)

Publication Number Publication Date
EP0128161A1 EP0128161A1 (en) 1984-12-19
EP0128161B1 true EP0128161B1 (en) 1987-03-25

Family

ID=6181041

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83903782A Expired EP0128161B1 (en) 1982-12-18 1983-11-22 Fuel nozzle for internal combustion engines

Country Status (5)

Country Link
EP (1) EP0128161B1 (en)
JP (1) JPS60500268A (en)
DE (2) DE3246916A1 (en)
IT (1) IT1170264B (en)
WO (1) WO1984002379A1 (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3515723A1 (en) * 1985-05-02 1986-11-06 Robert Bosch Gmbh, 7000 Stuttgart FUEL INJECTION NOZZLE FOR INTERNAL COMBUSTION ENGINES
GB8709712D0 (en) * 1987-04-24 1987-05-28 Lucas Ind Plc Fuel injection nozzle
ATE119238T1 (en) * 1989-01-12 1995-03-15 Bosch Robert Ag FUEL INJECTOR.
DE10318255A1 (en) * 2003-04-23 2004-11-25 Man B & W Diesel Ag Device for reducing the injection of an injection valve

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2451462A1 (en) * 1974-10-30 1976-05-06 Maschf Augsburg Nuernberg Ag INJECTION VALVE FOR RECEPTACLE COMBUSTION MACHINERY
IT1059704B (en) * 1975-04-19 1982-06-21 Cav Ltd FUEL INJECTION NOZZLE UNIT
DE3041018C2 (en) * 1980-10-31 1986-03-20 Daimler-Benz Ag, 7000 Stuttgart Fuel injection device for an air-compressing injection internal combustion engine
DE3120060A1 (en) * 1981-05-20 1982-12-09 Robert Bosch Gmbh, 7000 Stuttgart FUEL INJECTION NOZZLE FOR INTERNAL COMBUSTION ENGINES
DE3220398A1 (en) * 1982-01-26 1983-07-28 Robert Bosch Gmbh, 7000 Stuttgart FUEL INJECTION NOZZLE FOR INTERNAL COMBUSTION ENGINES

Also Published As

Publication number Publication date
DE3246916A1 (en) 1984-06-20
IT1170264B (en) 1987-06-03
WO1984002379A1 (en) 1984-06-21
IT8324156A0 (en) 1983-12-14
EP0128161A1 (en) 1984-12-19
DE3370514D1 (en) 1987-04-30
JPS60500268A (en) 1985-02-28

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