EP1518049A1 - Fuel injection valve for an internal combustion engine - Google Patents

Fuel injection valve for an internal combustion engine

Info

Publication number
EP1518049A1
EP1518049A1 EP03718631A EP03718631A EP1518049A1 EP 1518049 A1 EP1518049 A1 EP 1518049A1 EP 03718631 A EP03718631 A EP 03718631A EP 03718631 A EP03718631 A EP 03718631A EP 1518049 A1 EP1518049 A1 EP 1518049A1
Authority
EP
European Patent Office
Prior art keywords
valve
needle
hollow
combustion chamber
valve 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.)
Granted
Application number
EP03718631A
Other languages
German (de)
French (fr)
Other versions
EP1518049B1 (en
Inventor
Detlev Di Potz
Thomas Kuegler
Predrag Nunic
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 EP1518049A1 publication Critical patent/EP1518049A1/en
Application granted granted Critical
Publication of EP1518049B1 publication Critical patent/EP1518049B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • 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
    • F02M61/1806—Injection nozzles, e.g. having valve seats; Details of valve member seated ends, not otherwise provided for characterised by the arrangement of discharge orifices, e.g. orientation or size
    • F02M61/182—Discharge orifices being situated in different transversal planes with respect to valve member direction of movement
    • 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
    • F02M45/086—Having more than one injection-valve controlling discharge orifices
    • 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
    • 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
    • F02M61/1806—Injection nozzles, e.g. having valve seats; Details of valve member seated ends, not otherwise provided for characterised by the arrangement of discharge orifices, e.g. orientation or size
    • F02M61/1833—Discharge orifices having changing cross sections, e.g. being divergent
    • 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
    • F02M61/1866—Valve seats or member ends having multiple cones
    • 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
    • F02M61/1873—Valve seats or member ends having circumferential grooves or ridges, e.g. toroidal
    • 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
    • F02M2200/46—Valves, e.g. injectors, with concentric valve bodies

Definitions

  • the invention is based on a fuel injection valve for an internal combustion engine, as it corresponds to the preamble of claim 1.
  • a fuel injection valve for an internal combustion engine, as it corresponds to the preamble of claim 1.
  • a fuel injection valve is known, for example, from the published patent application DE 27 11 391 and has a valve body, in which a hollow valve needle is arranged to be longitudinally displaceable in a bore.
  • the valve hollow needle has a conical valve sealing surface on its combustion chamber end, with which it interacts with a conical valve seat which forms the combustion chamber end of the bore.
  • a valve needle is arranged to be longitudinally displaceable, which likewise has a conical valve contact surface and interacts with the valve seat.
  • Both the hollow valve needle and the valve needle control the fuel flow to at least one injection opening, through which fuel is injected into the combustion chamber of the internal combustion engine.
  • a fuel injection valve is known from the published patent application DE 27 11 390, in which the hollow valve needle has no flattening but tapers out sharply. Although this reduces the dead volume and thus has a favorable effect on the hydrocarbon emissions of the internal combustion engine, there is the disadvantage here that the inner needle can easily jam in the outer needle. Due to the fact that the hollow valve needle rests on the conical valve seat, the hollow valve needle is slightly deformed radially inwards, so that the already very small annular gap between the valve needle and the hollow valve needle is further reduced. This can lead to increased wear between these two components which are slidably mounted against one another, which leads to a reduction in the service life of the fuel injector.
  • the fuel injection valve according to the invention with the characterizing features of patent claim 1 has the advantage over the prior art that clamping of the valve needle in the hollow valve needle is effectively prevented while at the same time reducing hydrocarbon emissions from the fuel injection valve.
  • the hollow valve needle has a chamfer at its tip, which preferably adjoins the conical valve sealing surface directly. Since the outermost valve tip is no longer directly influenced by the force that is generated by pressing the hollow valve needle against the conical valve seat, the valve hollow needle is deformed to a significantly lesser extent, and this causes jamming or excessive wear on the loading - prevents movement of the valve needle in the hollow valve needle.
  • the volume between the hollow valve needle, the valve needle and the valve seat, when both the valve needle and the hollow valve needle rest against the valve seat remains so small that there is no significant increase in the hydrocarbon emissions of the internal combustion engine.
  • FIG. 1 shows a valve body in longitudinal section
  • FIG. 2 shows an enlargement of FIG. 1 in the area of the valve seat, the valve hollow needle being shown in section
  • L5 shows an embodiment of the fuel injection valve according to the invention
  • FIG. 3 shows the same detail as FIG. 2, the hollow valve needle being shown uncut here.
  • FIG. 1 shows a longitudinal section through a fuel injection valve according to the invention.
  • a bore 3 is formed in a valve body 1, and a conical valve seat 18 is formed at the end on the combustion chamber side.
  • a piston-shaped hollow valve needle 5 is arranged to be longitudinally displaceable.
  • the hollow valve needle 5 is sealingly guided in the section 3 facing away from the combustion chamber and tapers towards the valve seat 18 to form a pressure shoulder 14.
  • the hollow valve needle 5 has a conical valve sealing surface 24, which in the closed position of the hollow valve needle 5 on the valve seat 18 comes to the plant.
  • a pressure chamber 10 is formed between the hollow valve needle 5 and the wall of the bore 3 and is radially expanded at the level of the 5 pressure shoulder 14. In the radial expansion of the pressure chamber 10 opens a valve body 1 formed inlet channel 12, through which the pressure chamber 10 can be filled with fuel under high pressure.
  • the hollow valve needle 5 has a longitudinal bore 6, the longitudinal axis of which coincides with the longitudinal axis 8 of the hollow valve needle 5.
  • a valve needle 7 is arranged to be longitudinally displaceable, which has a conical valve contact surface 26 at its end on the combustion chamber side, which also comes into contact with the valve seat 18 in the closed position of the valve needle 7.
  • a first guide section 16 facing away from the combustion chamber and a second guide section 17 facing towards the combustion chamber are formed on the valve needle 7, in which it is guided relatively closely in the hollow valve needle 5.
  • the play between the second guide section 17 and the wall of the longitudinal bore 6 is very small, preferably less than 10 ⁇ m.
  • a relatively large annular gap is formed between these two guide sections 16, 17 between the valve needle 7 and the wall of the longitudinal bore 6, so that the valve needle 7 is actually only guided on the two guide sections 16, 17.
  • FIG. 2 shows an enlargement of FIG. 1 in the area of the valve seat 18 and FIG. 3 shows the same detail as FIG. 2, the hollow valve needle 5 not being shown here in section.
  • the hollow valve needle 5 bears against the valve seat 18, the valve sealing surface 24 closing the outer injection openings 20.
  • the valve needle 7 likewise closes the inner injection openings 22 with its valve contact surface 26.
  • annular groove 32 is formed on the valve needle 7, which is delimited on the one hand by the cylindrical section of the valve needle 7 and on the other hand by the valve contact surface 26 Annular groove 32 results in a contact surface for the fuel pressure of the pressure chamber 10 when the pressure acts on the valve needle 7.
  • Both the hollow valve needle 5 and the valve needle 7 are acted upon by a device (not shown in the drawing), for example a spring, with a closing force in the direction of the valve seat 18, so that they remain in their closed position in the absence of additional forces.
  • a device for example a spring
  • valve needle 7 initially remains in its closed position until the hydraulic pressure now acting on the pressure shoulder, which is formed by the annular groove 32, is sufficient to overcome the closing force on the valve needle 7. If the valve needle 7 also moves out of its closed position, fuel is injected in addition to the outer injection openings 20 also through the inner injection openings 22. If, on the other hand, injection is to take place only through the outer injection openings 20, the closing force is applied to the valve needle 7 held so high that it does not move out of its closed position due to the hydraulic pressure. In this way, only a part of the total injection cross section or the entire injection cross section can be controlled for the injection of fuel into the combustion chamber of the internal combustion engine.
  • Embodiment At the end of the hollow valve needle 5 on the combustion chamber side, in addition to the valve sealing surface 24, which comes into contact with the valve seat 18 in the closed position of the hollow valve needle 5 Embodiment another conical surface 124 formed, which borders on the valve sealing surface 24 and extends to the cylindrical region of the hollow valve needle 5.
  • the cone forming the conical surface of the chamfer 30, however, has a larger opening angle than the valve sealing surface 24.
  • the chamfer 30, prevents the hollow valve needle 5 from experiencing a radially inwardly directed force on its combustion-side end due to its contact with the conical valve seat 18, whereby the valve needle 7 can become jammed in the hollow valve needle 5.
  • the valve hollow needle 5 has a sufficient wall thickness in the area of the valve sealing surface 24, so that the closing force on the valve hollow needle 5 results in only a very slight deformation in the radial direction and the valve needle 7 maintains sufficient mobility in the longitudinal bore 6.
  • the chamfer 30 also ensures that the space between the hollow valve needle 7, the valve needle 5 and the valve seat 18 does not become too large.
  • valve sealing surface 24 Since the angles of inclination of the valve sealing surface 24, the valve contact surface 26 and the valve seat 18 are optimized so that a sealing of the injection openings 20, 22 against the pressure chamber 10 is ensured, it can happen that fuel from the valve seat 18 and the valve needles 5, 7 formed cavity in the injection breaks through the injection openings 20, 22 in the combustion chamber of the internal combustion engine and there leads to increased hydrocarbon emissions. This volume can be minimized by an appropriate angle of inclination of the chamfers 30 without impairing the wear reduction.

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

The invention relates to a fuel injection valve for an internal combustion engine, comprising a valve base (1) in which, in a bore (3), a valve hollow needle (5) is disposed so as to be longitudinally displaced. The valve hollow needle (5), at its combustion chamber end, is provided with a conical valve stem (24) that interacts with a conical valve seat (18) disposed at the combustion chamber end of the bore (3). In the valve hollow needle (5) a longitudinal bore (6) is configured in which a valve needle (7) is disposed which, with a valve locating face (26) configured at its combustion chamber end, likewise interacts with the valve seat (18). The combustion chamber end tip of the valve hollow needle (5) is formed by a chamfered element (30).

Description

Kraftstoffeinspritzventil für BrennkraftmaschinenFuel injection valve for internal combustion engines
Stand der TechnikState of the art
Die Erfindung geht von einem Kraftstoffeinspritzventil für Brennkraftmaschine aus, wie es dem Oberbegriff des Patentanspruchs 1 entspricht. Ein derartiges Kraftstoffeinspritzven- til ist beispielsweise aus der Offenlegungsschrift DE 27 11 391 bekannt und weist einen Ventilkörper auf, i dem in einer Bohrung eine Ventilhohlnadel längsverschiebbar angeordnet ist. Die Ventilhohlnadel weist an ihrem brennraumseitigen Ende eine konische Ventildichtfläche auf, mit der sie mit einem konischen Ventilsitz zusammenwirkt, der das brennraumseitige Ende der Bohrung bildet. In der Ventilhohlnadel ist eine Ventilnadel längsverschiebbar angeordnet, die ebenfalls eine konische Ventilanlagefläche aufweist und mit dem Ventilsitz zusammenwirkt. Sowohl die Ventilhohlnadel, als auch die Ventilnadel steuern den Kraftstofffluss zu jeweils wenigstens einer Einspritzöffnung, durch die Kraftstoff in den Brennraum der Brennkraftmaschine eingespritzt wird.The invention is based on a fuel injection valve for an internal combustion engine, as it corresponds to the preamble of claim 1. Such a fuel injection valve is known, for example, from the published patent application DE 27 11 391 and has a valve body, in which a hollow valve needle is arranged to be longitudinally displaceable in a bore. The valve hollow needle has a conical valve sealing surface on its combustion chamber end, with which it interacts with a conical valve seat which forms the combustion chamber end of the bore. In the hollow valve needle, a valve needle is arranged to be longitudinally displaceable, which likewise has a conical valve contact surface and interacts with the valve seat. Both the hollow valve needle and the valve needle control the fuel flow to at least one injection opening, through which fuel is injected into the combustion chamber of the internal combustion engine.
Bei dem bekannten Kraf stoffeinspritzventil aus der DE 27 11 391 ist die Spitze der Ventilhohlnadel abgeflacht, so dass eine Stirnfläche gebildet wird, die in einer Radial- ebene der Ventilhohlnadel liegt. Diese Ventilnadel weist hierbei jedoch den Nachteil auf, dass sich zwischen der Ven- tilhohlnadel, der Ventilnadel und dem Ventilsitz ein relativ großes Totvolumen bildet, was sich ungünstig auf die Kohlenwasserstoff-Emissionen des Kraftstoffeinspritzventils auswirkt .In the known fuel injection valve from DE 27 11 391, the tip of the hollow valve needle is flattened, so that an end face is formed which lies in a radial plane of the hollow valve needle. However, this valve needle has the disadvantage that between the valve tilhohlnadel, the valve needle and the valve seat forms a relatively large dead volume, which has an adverse effect on the hydrocarbon emissions of the fuel injector.
Darüber hinaus ist aus der Offenlegungsschrift DE 27 11 390 ein Kraftstoffeinspritzventil bekannt, bei dem die Ventilhohlnadel keine Abflachung aufweist, sondern spitz ausläuft. Dies verringert zwar das Totvolumen und wirkt sich damit günstig auf die Kohlenwasserstoff-Emissionen der Brennkraftmaschine aus, jedoch ergibt sich hier der Nachteil, dass die Innennadel leicht in der Außennadel klemmen kann. Durch die Anlage der Ventilhohlnadel am konischen Ventilsitz kommt es zu einem leichten Verformen der Ventilhohlnadel radial nach innen, so dass sich der ohnehin nur sehr kleine Ringspalt zwischen der Ventilnadel und der Ventilhohlnadel weiter verringert. Dadurch kann es zu einem erhöhten Verschleiß zwischen diesen beiden gleitverschiebbar gegeneinander gelagerten Bauteilen kommen, was zu einer Verminderung der Lebens- dauer des Kraftstoffeinspritzventil führt.In addition, a fuel injection valve is known from the published patent application DE 27 11 390, in which the hollow valve needle has no flattening but tapers out sharply. Although this reduces the dead volume and thus has a favorable effect on the hydrocarbon emissions of the internal combustion engine, there is the disadvantage here that the inner needle can easily jam in the outer needle. Due to the fact that the hollow valve needle rests on the conical valve seat, the hollow valve needle is slightly deformed radially inwards, so that the already very small annular gap between the valve needle and the hollow valve needle is further reduced. This can lead to increased wear between these two components which are slidably mounted against one another, which leads to a reduction in the service life of the fuel injector.
Vorteile der ErfindungAdvantages of the invention
Das erfindungsgemäße Kraftstoffeinspritzventil mit den kenn- zeichnenden Merkmalen des Patentanspruchs 1 weist demgegenüber den Vorteil auf, dass ein Klemmen der Ventilnadel in der Ventilhohlnadel wirksam unterbunden wird bei gleichzeitig verminderten Kohlenwasserstoff-Emissionen des Kraftstoffeinspritzventils . Hierzu weist die Ventilhohlnadel an ihrer Spitze eine Anfasung auf, die sich vorzugsweise direkt an die konische Ventildichtfläche anschließt. Da die äußerste Ventilspitze nun nicht mehr direkt von der Kraft, die durch das Anpressen der Ventilhohlnadel am konischen Ventilsitz erzeugt wird, beeinflusst wird, ergibt sich eine deut- lieh geringere Einformung der Ventilhohlnadel, und damit wird ein Klemmen oder ein übermäßiger Verschleiß bei der Be- wegung der Ventilnadel in der Ventilhohlnadel verhindert. Gleichzeitig bleibt das Volumen zwischen der Ventilhohlnadel, der Ventilnadel und dem Ventilsitz, wenn sowohl die Ventilnadel als auch die Ventilhohlnadel am Ventilsitz an- 5 liegen, so gering, dass es zu keinem bedeutenden Anstieg der Kohlenwasserstoff-Emissionen der Brennkraftmaschine kommt.The fuel injection valve according to the invention with the characterizing features of patent claim 1 has the advantage over the prior art that clamping of the valve needle in the hollow valve needle is effectively prevented while at the same time reducing hydrocarbon emissions from the fuel injection valve. For this purpose, the hollow valve needle has a chamfer at its tip, which preferably adjoins the conical valve sealing surface directly. Since the outermost valve tip is no longer directly influenced by the force that is generated by pressing the hollow valve needle against the conical valve seat, the valve hollow needle is deformed to a significantly lesser extent, and this causes jamming or excessive wear on the loading - prevents movement of the valve needle in the hollow valve needle. At the same time, the volume between the hollow valve needle, the valve needle and the valve seat, when both the valve needle and the hollow valve needle rest against the valve seat, remains so small that there is no significant increase in the hydrocarbon emissions of the internal combustion engine.
Zeichnungdrawing
L0 In der Zeichnung ist ein Ausführungsbeispiel des erfindungsgemäßen Kraftstoffeinspritzventils dargestellt. Es zeigt Figur 1 einen Ventilkörper im Längsschnitt, Figur 2 eine Vergrößerung von Figur 1 im Bereich des Ventilsitzes, wobei die Ventilhohlnadel ge- L5 schnitten dargestellt ist undL0 In the drawing, an embodiment of the fuel injection valve according to the invention is shown. 1 shows a valve body in longitudinal section, FIG. 2 shows an enlargement of FIG. 1 in the area of the valve seat, the valve hollow needle being shown in section and L5
Figur 3 denselben Ausschnitt wie Figur 2, wobei hier die Ventilhohlnadel ungeschnitten gezeigt ist.3 shows the same detail as FIG. 2, the hollow valve needle being shown uncut here.
Beschreibung des AusführungsbeispielsDescription of the embodiment
2020
In Figur 1 ist ein Längsschnitt durch ein erfindungsgemäßes Kraftstoffeinspritzventil dargestellt. In einem Ventilkörper 1 ist eine Bohrung 3 ausgebildet, an deren brennraumseitigen Ende ein konischer Ventilsitz 18 ausgebildet ist. In derFIG. 1 shows a longitudinal section through a fuel injection valve according to the invention. A bore 3 is formed in a valve body 1, and a conical valve seat 18 is formed at the end on the combustion chamber side. In the
25 Bohrung 3, die eine Längsachse 8 aufweist, ist eine kolbenförmige Ventilhohlnadel 5 längsverschiebbar angeordnet. Die Ventilhohlnadel 5 wird in einem brennraumabgewandten Abschnitt in der Bohrung 3 dichtend geführt und verjüngt sich dem Ventilsitz 18 zu unter Bildung einer Druckschulter 14. 0 An ihrem brennraumseitigen Ende weist die Ventilhohlnadel 5 eine konische Ventildichtfläche 24 auf, die in Schließstellung der Ventilhohlnadel 5 am Ventilsitz 18 zur Anlage kommt. Zwischen der Ventilhohlnadel 5 und der Wand der Bohrung 3 ist ein Druckraum 10 ausgebildet, der auf Höhe der 5 Druckschulter 14 radial erweitert ist. In die radiale Erweiterung des Druckraums 10 mündet ein im Ventilkörper 1 ausge- bildeter Zulaufkanal 12, über den der Druckraum 10 mit Kraftstoff unter hohem Druck befüllt werden kann.25 bore 3, which has a longitudinal axis 8, a piston-shaped hollow valve needle 5 is arranged to be longitudinally displaceable. The hollow valve needle 5 is sealingly guided in the section 3 facing away from the combustion chamber and tapers towards the valve seat 18 to form a pressure shoulder 14. At its end on the combustion chamber side, the hollow valve needle 5 has a conical valve sealing surface 24, which in the closed position of the hollow valve needle 5 on the valve seat 18 comes to the plant. A pressure chamber 10 is formed between the hollow valve needle 5 and the wall of the bore 3 and is radially expanded at the level of the 5 pressure shoulder 14. In the radial expansion of the pressure chamber 10 opens a valve body 1 formed inlet channel 12, through which the pressure chamber 10 can be filled with fuel under high pressure.
Die Ventilhohlnadel 5 weist eine Längsbohrung 6 auf, deren Längsachse mit der Längsachse 8 der Ventilhohlnadel 5 zusammenfällt. In der Längsbohrung 6 ist eine Ventilnadel 7 längsverschiebbar angeordnet, die an ihrem brennraumseitigen Ende eine konische Ventilanlagefläche 26 aufweist, die in Schließstellung der Ventilnadel 7 ebenfalls am Ventilsitz 18 zur Anlage kommt. An der Ventilnadel 7 ist ein brennraumab- gewandter, erster Führungsabschnitt 16 und ein brennraumzu- gewandter, zweiter Führungsabschnitt 17 ausgebildet, in denen sie relativ eng in der Ventilhohlnadel 5 geführt ist. Das Spiel zwischen dem zweiten Führungsabschnitt 17 und der Wand der Längsbohrung 6 ist dabei sehr gering, vorzugsweise weniger als 10 μm. Zwischen diesen beiden Führungsabschnitten 16, 17 ist ein relativ großer Ringspalt zwischen der Ventilnadel 7 und der Wand der Längsbohrung 6 ausgebildet, so dass die Ventilnadel 7 nur an den beiden Führungsab- schnitten 16, 17 tatsächlich geführt wird.The hollow valve needle 5 has a longitudinal bore 6, the longitudinal axis of which coincides with the longitudinal axis 8 of the hollow valve needle 5. In the longitudinal bore 6, a valve needle 7 is arranged to be longitudinally displaceable, which has a conical valve contact surface 26 at its end on the combustion chamber side, which also comes into contact with the valve seat 18 in the closed position of the valve needle 7. A first guide section 16 facing away from the combustion chamber and a second guide section 17 facing towards the combustion chamber are formed on the valve needle 7, in which it is guided relatively closely in the hollow valve needle 5. The play between the second guide section 17 and the wall of the longitudinal bore 6 is very small, preferably less than 10 μm. A relatively large annular gap is formed between these two guide sections 16, 17 between the valve needle 7 and the wall of the longitudinal bore 6, so that the valve needle 7 is actually only guided on the two guide sections 16, 17.
Ausgehend vom Ventilsitz 18 sind im Ventilkörper 1 äußere Einspritzöffnungen 20 und innere Einspritzöffnungen 22 ausgebildet, von denen vorzugsweise mehrere über den Umfang des Ventilkörpers 1 verteilt angeordnet sind. Figur 2 zeigt hierzu eine Vergrößerung von Figur 1 im Bereich des Ventilsitzes 18 und Figur 3 nochmals denselben Ausschnitt wie Figur 2, wobei die Ventilhohlnadel 5 hier nicht geschnitten dargestellt ist. Die Ventilhohlnadel 5 liegt in ihrer Schließstellung am Ventilsitz 18 an, wobei die Ventildichtfläche 24 die äußeren Einspritzöffnungen 20 verschließt. E- benso verschließt die Ventilnadel 7 mit ihrer Ventilanlagefläche 26 die inneren Einspritzöffnungen 22. An der Ventilnadel 7 ist eine Ringnut 32 ausgebildet, die einerseits vom zylindrischen Abschnitt der Ventilnadel 7 begrenzt wird und andererseits von der Ventilanlagefläche 26. Durch diese Ringnut 32 ergibt sich eine Angriffsfläche für den Kraftstoffdruck des Druckraums 10, wenn der Druck die Ventilnadel 7 beaufschlagt.Starting from the valve seat 18, outer injection openings 20 and inner injection openings 22 are formed in the valve body 1, several of which are preferably arranged distributed over the circumference of the valve body 1. FIG. 2 shows an enlargement of FIG. 1 in the area of the valve seat 18 and FIG. 3 shows the same detail as FIG. 2, the hollow valve needle 5 not being shown here in section. In its closed position, the hollow valve needle 5 bears against the valve seat 18, the valve sealing surface 24 closing the outer injection openings 20. The valve needle 7 likewise closes the inner injection openings 22 with its valve contact surface 26. An annular groove 32 is formed on the valve needle 7, which is delimited on the one hand by the cylindrical section of the valve needle 7 and on the other hand by the valve contact surface 26 Annular groove 32 results in a contact surface for the fuel pressure of the pressure chamber 10 when the pressure acts on the valve needle 7.
Sowohl die Ventilhohlnadel 5 als auch die Ventilnadel 7 werden von einer in der Zeichnung nicht dargestellten Vorrichtung, beispielsweise einer Feder, mit einer Schließkraft in Richtung des Ventilsitzes 18 beaufschlagt, so dass sie bei Fehlen weiterer Kräfte in ihrer Schließstellung bleiben. Durch Einleitung von Kraftstoff unter entsprechendem Einspritzdruck in den Druckraum 10 des Ventilkörpers 1 ergibt sich eine hydraulische Kraft auf die Druckschulter 14, die der Schließkraft auf die Ventilhohlnadel 5 entgegengerichtet ist. Übersteigt diese hydraulische Kraft die Schließkraft, so hebt die Ventilhohlnadel 5 vom Ventilsitz 18 ab und gibt die äußeren Einspritzöffnungen 20 frei, durch welche Kraftstoff in den Brennraum der Brennkraftmaschine eingespritzt wird. Die Ventilnadel 7 verbleibt vorerst in ihrer Schließstellung, bis der jetzt wirkende hydraulischen Druck auf die Druckschulter, die durch die Ringnut 32 gebildet wird, ausreicht, die Schließkraft auf die Ventilnadel 7 zu überwinden. Bewegt sich auch die Ventilnadel 7 aus ihrer Schließstellung, so erfolgt die Einspritzung von Kraftstoff zusätzlich zu den äußeren Einspritzöffnungen 20 auch durch die in- neren Einspritzöffnungen 22. Soll hingegen nur durch die äußeren Einspritzöffnungen 20 eingespritzt werden, so wird die Schließkraft auf die Ventilnadel 7 so hoch gehalten, dass sie sich durch den hydraulischen Druck nicht aus ihrer Schließstellung bewegt. Auf diese Weise lässt sich für die Einspritzung von Kraftstoff in den Brennraum der Brennkraftmaschine nur ein Teil des gesamten Einspritzquerschnitts o- der der gesamte Einspritzquerschnitt aufsteuern.Both the hollow valve needle 5 and the valve needle 7 are acted upon by a device (not shown in the drawing), for example a spring, with a closing force in the direction of the valve seat 18, so that they remain in their closed position in the absence of additional forces. By introducing fuel under appropriate injection pressure into the pressure chamber 10 of the valve body 1, a hydraulic force is exerted on the pressure shoulder 14, which counteracts the closing force on the hollow valve needle 5. If this hydraulic force exceeds the closing force, the hollow valve needle 5 lifts off the valve seat 18 and opens the outer injection openings 20, through which fuel is injected into the combustion chamber of the internal combustion engine. The valve needle 7 initially remains in its closed position until the hydraulic pressure now acting on the pressure shoulder, which is formed by the annular groove 32, is sufficient to overcome the closing force on the valve needle 7. If the valve needle 7 also moves out of its closed position, fuel is injected in addition to the outer injection openings 20 also through the inner injection openings 22. If, on the other hand, injection is to take place only through the outer injection openings 20, the closing force is applied to the valve needle 7 held so high that it does not move out of its closed position due to the hydraulic pressure. In this way, only a part of the total injection cross section or the entire injection cross section can be controlled for the injection of fuel into the combustion chamber of the internal combustion engine.
Am brennraumseitigen Ende der Ventilhohlnadel 5 ist neben der Ventildichtfläche 24, die am Ventilsitz 18 in Schließstellung der Ventilhohlnadel 5 zur Anlage kommt, in diesem Ausführungsbeispiel eine weitere Konusfläche 124 ausgebildet, die an die Ventildichtfläche 24 grenzt und bis zum zylindrischen Bereich der Ventilhohlnadel 5 reicht. An die Ventildichtfläche 24 schließt sich zum Ventilsitz 18 hin ei- ne Anfasung 30 an, die eine Konusfläche bildet. Dadurch ist die Anfasung 30 gegenüber der Radialebene der Längsachse 8 geneigt. Der die Konusfläche der Anfasung 30 bildende Kegel weist jedoch einen größeren Öffnungswinkel auf als die Ventildichtfläche 24. Die Anfasung 30 verhindert zum einen, dass die Ventilhohlnadel 5 durch ihre Anlage am konischen Ventilsitz 18 eine radial nach innen gerichtete Kraft auf ihr brennrau seitiges Ende erfährt, wodurch es zu einem Klemmen der Ventilnadel 7 in der Ventilhohlnadel 5 kommen kann. Die Ventilhohlnadel 5 weist im Bereich der Ventil- dichtfläche 24 jedoch eine ausreichende Wandstärke auf, so dass es durch die Schließkraft auf die Ventilhohlnadel 5 nur zu einer sehr geringen Einformung in radialer Richtung kommt und die Ventilnadel 7 eine ausreichende Beweglichkeit in der Längsbohrung 6 behält. Durch die Anfasung 30 ist im Gegen- satz zu einer Abflachung aber auch sichergestellt, dass der Raum zwischen der Ventilhohlnadel 7, der Ventilnadel 5 und dem Ventilsitz 18 nicht zu groß wird. Da die Neigungswinkel der Ventildichtfläche 24, der Ventilanlagefläche 26 und des Ventilsitzes 18 so optimiert sind, dass eine Abdichtung der Einspritzöffnungen 20, 22 gegen den Druckraum 10 sichergestellt ist, kann es vorkommen, dass Kraftstoff aus dem zwischen dem Ventilsitz 18 und den Ventilnadeln 5, 7 gebildeten Hohlraum in den Einspritzpausen durch die Einspritzöffnungen 20, 22 in den Brennraum der Brennkraftmaschine gelangt und dort zu erhöhten Kohlenwasserstoff-Emissionen führt. Durch einen entsprechenden Neigungswinkel der Anfasungen 30 lässt sich dieses Volumen minimieren, ohne die Verschleißminderung zu beeinträchtigen. At the end of the hollow valve needle 5 on the combustion chamber side, in addition to the valve sealing surface 24, which comes into contact with the valve seat 18 in the closed position of the hollow valve needle 5 Embodiment another conical surface 124 formed, which borders on the valve sealing surface 24 and extends to the cylindrical region of the hollow valve needle 5. A chamfer 30, which forms a conical surface, adjoins the valve sealing surface 24 toward the valve seat 18. As a result, the chamfer 30 is inclined with respect to the radial plane of the longitudinal axis 8. The cone forming the conical surface of the chamfer 30, however, has a larger opening angle than the valve sealing surface 24. The chamfer 30, on the one hand, prevents the hollow valve needle 5 from experiencing a radially inwardly directed force on its combustion-side end due to its contact with the conical valve seat 18, whereby the valve needle 7 can become jammed in the hollow valve needle 5. However, the valve hollow needle 5 has a sufficient wall thickness in the area of the valve sealing surface 24, so that the closing force on the valve hollow needle 5 results in only a very slight deformation in the radial direction and the valve needle 7 maintains sufficient mobility in the longitudinal bore 6. In contrast to flattening, the chamfer 30 also ensures that the space between the hollow valve needle 7, the valve needle 5 and the valve seat 18 does not become too large. Since the angles of inclination of the valve sealing surface 24, the valve contact surface 26 and the valve seat 18 are optimized so that a sealing of the injection openings 20, 22 against the pressure chamber 10 is ensured, it can happen that fuel from the valve seat 18 and the valve needles 5, 7 formed cavity in the injection breaks through the injection openings 20, 22 in the combustion chamber of the internal combustion engine and there leads to increased hydrocarbon emissions. This volume can be minimized by an appropriate angle of inclination of the chamfers 30 without impairing the wear reduction.

Claims

Ansprüche Expectations
1. Kraftstoffeinspritzventil für Brennkraftmaschinen mit einem Ventilkörper (1) , in dem in einer Bohrung (3) eine Ventilhohlnadel (5) längsverschiebbar angeordnet ist, welche an ihrem brennraumseitigen Ende eine konische Ven- tildichtflache (24) aufweist, die mit einem am brennraumseitigen Ende der Bohrung (3) angeordneten konischen Ventilsitz (18) zusammenwirkt, und mit einer in der Ventilhohlnadel (5) ausgebildeten Längsbohrung (6), in der eine Ventilnadel (7) angeordnet ist, die mit einer an ihrem brennraumseitigen Ende ausgebildeten Ventilanlageflachte1. Fuel injection valve for internal combustion engines with a valve body (1), in which a hollow valve needle (5) is arranged so as to be longitudinally displaceable in a bore (3), which has a conical valve sealing surface (24) at its end on the combustion chamber side, which has an end on the combustion chamber side the bore (3) arranged conical valve seat (18) cooperates, and with a in the valve hollow needle (5) formed longitudinal bore (6), in which a valve needle (7) is arranged, which is flattened with a valve system on its combustion chamber end
(26) ebenfalls mit dem Ventilsitz (18) zusammenwirkt, dadurch gekennzeichnet, dass an der brennraumseitigen Spitze der Ventilhohlnadel (5) eine Anfasung (30) gebildet ist.(26) also interacts with the valve seat (18), characterized in that a chamfer (30) is formed on the tip of the hollow valve needle (5) on the combustion chamber side.
2. Kraftstoffeinspritzventil nach Anspruch 1, dadurch gekennzeichnet, dass die Anfasung (30) der Ventilhohlnadel (5) eine konische Fläche bildet, die sich direkt an die konische Ventildichtfläche (24) anschließt.2. Fuel injection valve according to claim 1, characterized in that the chamfer (30) of the hollow valve needle (5) forms a conical surface which directly adjoins the conical valve sealing surface (24).
3. Kraftstoffeinspritzventil nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass die Anfasung (30) an ihrem brennraumseitigen inneren Rand direkt an die Innenmantelfläche der Längsbohrung (6) der Ventilhohlnadel (5) grenzt. 3. Fuel injection valve according to claim 1 or 2, characterized in that the chamfer (30) directly borders on the inner peripheral surface of the longitudinal bore (6) of the hollow valve needle (5) at its combustion chamber-side inner edge.
4. Kraftstoffeinspritzventil nach Anspruch 1, dadurch gekennzeichnet, dass die Ventilnadel (7) in ihrem brennraumseitigen Endbereich mit geringem Spiel in der Ventilhohlnadel (5) geführt wird.4. Fuel injection valve according to claim 1, characterized in that the valve needle (7) in its combustion chamber end region is guided with little play in the hollow valve needle (5).
5. Kraftstoffeinspritzventil nach Anspruch 4, dadurch gekennzeichnet, dass das Spiel weniger als 10 μm beträgt. 5. Fuel injection valve according to claim 4, characterized in that the game is less than 10 microns.
EP03718631A 2002-06-19 2003-03-26 Fuel injection valve for an internal combustion engine Expired - Lifetime EP1518049B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10227277 2002-06-19
DE10227277A DE10227277A1 (en) 2002-06-19 2002-06-19 Fuel injection valve for internal combustion engines
PCT/DE2003/000991 WO2004001219A1 (en) 2002-06-19 2003-03-26 Fuel injection valve for an internal combustion engine

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EP1518049A1 true EP1518049A1 (en) 2005-03-30
EP1518049B1 EP1518049B1 (en) 2006-05-10

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EP (1) EP1518049B1 (en)
JP (1) JP2005530091A (en)
CN (1) CN100370132C (en)
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DE10351881A1 (en) * 2003-10-30 2005-06-02 Robert Bosch Gmbh Injector with structures for limiting wear-related changes of an opening course
TR200402050A2 (en) * 2004-08-18 2006-03-21 Robert Bosch Gmbh Dual seating diameter injector with coaxial areal contact
DE112006000809T5 (en) * 2005-04-06 2008-02-07 GM Global Technology Operations, Inc., Detroit Double-row cluster configuration with injectors for reduced soot emissions
EP2943678B1 (en) * 2013-01-11 2019-04-24 KW Technologie GmbH & Co. KG Device for spraying liquid into a combustion chamber
JP5716788B2 (en) * 2013-04-25 2015-05-13 株式会社デンソー Fuel injection valve
GB201309122D0 (en) * 2013-05-21 2013-07-03 Delphi Tech Holding Sarl Fuel Injector
DE102014224348A1 (en) * 2014-11-28 2016-06-02 Robert Bosch Gmbh Direct injection gas injector with improved opening and closing behavior
JP2017008861A (en) * 2015-06-24 2017-01-12 株式会社デンソー Fuel injection nozzle
JP6507890B2 (en) * 2015-07-02 2019-05-08 株式会社デンソー Fuel injection valve
US10453490B2 (en) 2017-12-19 2019-10-22 Panasonic Intellectual Property Management Co., Ltd. Optical disc device

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US20050139698A1 (en) 2005-06-30
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JP2005530091A (en) 2005-10-06
DE10227277A1 (en) 2004-01-08
CN100370132C (en) 2008-02-20
EP1518049B1 (en) 2006-05-10
US7044406B2 (en) 2006-05-16
CN1662742A (en) 2005-08-31

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