EP1623108B1 - Fuel injection valve for internal combustion engines - Google Patents

Fuel injection valve for internal combustion engines Download PDF

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Publication number
EP1623108B1
EP1623108B1 EP04704544A EP04704544A EP1623108B1 EP 1623108 B1 EP1623108 B1 EP 1623108B1 EP 04704544 A EP04704544 A EP 04704544A EP 04704544 A EP04704544 A EP 04704544A EP 1623108 B1 EP1623108 B1 EP 1623108B1
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EP
European Patent Office
Prior art keywords
conical section
fuel injection
valve
conical
injection
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EP04704544A
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German (de)
French (fr)
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EP1623108A1 (en
Inventor
Juergen Schubert
Beate Grota
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Robert Bosch GmbH
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Robert Bosch GmbH
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    • 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
    • F02M61/1846—Dimensional characteristics of 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
    • 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

Definitions

  • the invention is based on a fuel injection valve for internal combustion engines, as for example from the EP 352 926 A1 is known.
  • a fuel injection valve has a valve body in which a pressure chamber is formed.
  • the pressure chamber has a wall, from which at least one injection channel goes off.
  • the inlet opening of the injection channel is arranged in the wall of the pressure chamber, while the outlet opening is ah the outside of the valve body.
  • the WO 02/063161 shows an injection valve in which a valve needle cooperates with a conical valve seat to control the injection. From the valve seat is at least one injection opening, which has a waist and may be formed conically in the region of the inlet, wherein the conical inlet narrows in the flow direction.
  • an injection valve in which a valve member cooperates with a conical valve seat. From the valve seat goes from an injection port, which is either conical, tapering in the flow direction or has a cylindrical and a tapered portion.
  • the SU 1740756 A1 shows an injection valve with an injection opening, which consists of two conical sections.
  • the first conical section narrows in the direction of flow, while the second conical section expands, so that a waisted injection channel is formed, which has a narrowest cross-section.
  • the fuel injection valve according to the invention for internal combustion engines with the features of independent claim 1 has the advantage that it comes with a simple to manufacture geometry of the injection channel to lower deflection losses when the fuel enters the injection channel and thus to a good atomization and directional stability of the injection jet.
  • the injection channel as seen in the flow direction, has a first conical section and an adjoining second conical section. Both conical sections taper in the flow direction, so that the cross section of the injection channel decreases from the inlet opening to the outlet opening.
  • each conical section can assume a separate function, to which it is adapted separately.
  • a strong conicity gives a high acceleration of the fuel in the injection channel, while a small conicity mainly contributes to a good directional stability, so that the injection jet reaches exactly the intended space region of the combustion chamber. Play the deflection losses when the fuel enters the injection channel only a minor role, it can be freely chosen which of the two conical sections should have the greater taper.
  • the opening angle of the first conical section of the injection channel is greater than the opening angle of the second conical section. This ensures that the fuel when entering the injection channel a less change in direction must perform and thus at this point the energy losses are reduced.
  • the second conical section which has a smaller opening angle, there is a good directional stability of the injection jet at the same time good atomization. It is particularly advantageous in this case if the transition edge between the first conical section and the second conical section is rounded. As a result, less turbulence is generated in the injection channel, which reduces the risk of cavitation.
  • the length of the first conical section is greater than the length of the second conical section.
  • the first conical section has a smaller opening angle than the second conical section. If the deflecting losses on entry of the fuel into the injection channel are of little significance due to the special conditions in this injection valve, then in this design of the conical sections of the injection channel an optimization with respect to the directional stability can be undertaken.
  • FIG. 1 a fuel injection valve according to the invention is shown in longitudinal section.
  • a pressure chamber 19 is formed by a blind bore 3, which is radially expanded in a central portion, wherein the remaining valve body 1 forms a wall around the pressure chamber 19.
  • a conical valve seat 9 is formed, from which at least one, but usually several injection channels 11 depart, which open into the mounting position of the fuel injection valve in the combustion chamber of the internal combustion engine.
  • a piston-shaped valve needle 5 is arranged longitudinally displaceable.
  • valve needle 5 is sealingly guided in a guide section 23 of the blind bore 3 in a guide section 23 remote from the combustion chamber and tapers to the valve seat 9 to form a pressure shoulder 13, which is arranged in the radial extension of the pressure chamber 19.
  • a substantially conical valve sealing surface 7 is formed, with which the valve needle 5 cooperates with the valve seat 9.
  • the valve needle 5 is acted upon at its end remote from the combustion chamber by a closing force, which is generated for example by a spring element, not shown in the drawing, through which the valve needle 5 is pressed against the valve seat 9.
  • the closing force is a hydraulic force acting on the pressure shoulder 13 opposing force.
  • the valve needle 5 either moves away from the valve seat 9 and releases the injection channels 11, or the valve needle 5 is pressed by the closing force against the valve seat 9, so that the injection channels 11 are closed.
  • fuel flows from the pressure chamber 19 to the injection channels 11 and is injected from there into the combustion chamber of the internal combustion engine. This injection is done under high pressure, so that a good atomization of the fuel and thus a low-emission combustion is achieved.
  • FIG. 2 shows an enlargement of FIG. 1 in the region of the valve seat 9.
  • the injection channel 11 has an inlet opening 30, which is arranged in the valve seat 9.
  • the outlet opening 32 of the injection channel 11 is located on the outside of the valve body 1, so that the injection channel 11 penetrates the wall of the pressure chamber 19.
  • the injection channel 11 has a first conical portion 35 and a second conical portion 37 which adjoin one another. At the transition from the first conical portion 35 to the second conical portion 37 of a transition edge 38 is formed, which is seen in the axial direction of the injection channel 11, for example, in the middle between the inlet opening 30 and the outlet opening 32 is arranged.
  • the fuel injection valve is shown in the open state, that is, the valve needle 5 from Valve seat 9 has lifted.
  • FIG. 3 again shows the injection channel 11 in an enlarged view.
  • the first conical section 35 has an opening angle ⁇ 1 which is greater than the opening angle ⁇ 2 of the second conical section 37.
  • the length of the first conical section 35 is designated by a, the length a preferably being greater than the length b of the first conical section second conical section 37.
  • the ratio of the lengths a, b to each other can be varied as desired. It has proven to be particularly advantageous if the first conical section 35 has a length a which is 3 to 10 times greater than the length b of the second conical section 37.
  • the inlet edge 40 formed at the inlet opening 30 is preferably rounded to prevent flow separation in this area and to reduce the deflection losses.
  • the exit edge 42 formed at the outlet opening 32 may be rounded or sharp-edged, which depends on the injection pressure and diameter the outlet opening 32 causes a better atomization of the fuel jet.
  • FIG. 4 shows a further embodiment of the injection channel 11 according to the invention.
  • the structure of the injection channel 11 corresponds to that of FIG. 3
  • the transition edge 38 which is formed at the transition from the first conical portion 35 to the second conical portion 37, rounded.
  • Such a rounding of the transition edge 38 is particularly advantageous when a large amount of fuel to flow through the injection channel 11 at high speed.
  • flow separation of the fuel from the wall of the injection channel 11 may otherwise occur at this point, which manifests itself in an increased flow resistance and thus in a lower effective injection pressure.
  • FIG. 5 a further embodiment of the injection channel 11 according to the invention is shown.
  • the ratio of the opening angles ⁇ 1 , ⁇ 2 of the first conical section 35 and the second conical section 37 are here inverted compared to the previous embodiments, that is, the opening angle ⁇ 1 of the first conical section 35 is smaller than the opening angle ⁇ 2 of the second Conical section 37.
  • the first conical section 35 is formed with a small conicity, that is to say with a relatively small opening angle ⁇ 1 , so that the cross section only decreases slowly in the direction of the outlet opening 32. This limits the pressure loss and causes directional stability.
  • the second conical section 37 is relatively strong conical, ie formed with a large opening angle ⁇ 2 , to ensure sufficient acceleration of the fuel before exiting the injection channel 11.
  • the total length of the injection channel 11 is, depending on the type of fuel injection valve, between 0.5 and 2 mm.
  • the diameter of the outlet opening 32 is 60 microns to 150 microns, while the diameter of the inlet opening 30 is at least 20 microns larger, preferably 20 microns to 60 microns.

Description

Die Erfindung geht von einem Kraftstoffeinspritzventil für Brennkraftmaschinen aus, wie es beispielsweise aus der EP 352 926 A1 bekannt ist. Ein solches Kraftstoffeinspritzventil weist einen Ventilkörper auf, in dem ein Druckraum ausgebildet ist. Der Druckraum weist eine Wandung auf, von der wenigstens ein Einspritzkanal abgeht. Hierbei ist die Eintrittsöffnung des Einspritzkanals in der Wand des Druckraums angeordnet, während sich die Austrittsöffnung ah der Außenseite des Ventilkörpers befindet.The invention is based on a fuel injection valve for internal combustion engines, as for example from the EP 352 926 A1 is known. Such a fuel injection valve has a valve body in which a pressure chamber is formed. The pressure chamber has a wall, from which at least one injection channel goes off. Here, the inlet opening of the injection channel is arranged in the wall of the pressure chamber, while the outlet opening is ah the outside of the valve body.

Aus dem Stand der Technik sind verschiedene Geometrien der Einspritzkanäle bekannt. So ist in der EP 352 926. A1 ein Einspritzkanal gezeigt, der gleichförmig konisch ausgebildet ist. Der Kraftstoff. wird durch den konisch zulaufenden Einspritzkanal beschleunigt und mit hoher Austrittsgeschwindigkeit und daraus resultierender guter Zerstäubung in den Brennraum der Brennkraftmaschine eingespritzt wird. Ein gleichförmig konisch ausgebildeter Einspritzkanal weist hierbei jedoch den Nachteil auf, dass es beim Eintritt des Kraftstoffs in den Einspritzkanal zu einer relativ starken Umlenkung des Kraftstoffstroms kommt und damit zu erheblichen Energieverlusten, was sich in einem erniedrigten effektiven Einspritzdruck bemerkbar macht. Dies mindert die Zerstäubung und führt zu einer nicht optimalen Verbrennung des Kraftstoffs.Various geometries of the injection channels are known from the prior art. So is in the EP 352 926 A1 shown an injection channel which is uniformly conical. The fuel. is accelerated by the tapered injection channel and injected at high exit velocity and resulting good atomization in the combustion chamber of the internal combustion engine. However, a uniformly conical injection channel here has the disadvantage that when the fuel enters the injection channel, there is a relatively strong deflection of the fuel flow and thus considerable energy losses, which is manifested in a reduced effective injection pressure. This reduces the atomization and leads to a non-optimal combustion of the fuel.

Die WO 02/063161 zeigt ein Einspritzventil, bei dem eine Ventilnadel mit einem konischen Ventilsitz zur Steuerung der Einspritzung zusammenwirkt. Vom Ventilsitz geht wenigstens eine Einspritzöffnung aus, die eine Taille aufweist und im Bereich des Einlaufs konisch ausgebildet sein kann, wobei sich der konische Einlauf in Strömungsrichtung verengt.The WO 02/063161 shows an injection valve in which a valve needle cooperates with a conical valve seat to control the injection. From the valve seat is at least one injection opening, which has a waist and may be formed conically in the region of the inlet, wherein the conical inlet narrows in the flow direction.

Aus der JP 01-300055 ist weiterhin ein Einspritzventil bekannt, bei dem ein Ventilglied mit einem konischen Ventilsitz zusammenwirkt. Vom Ventilsitz geht eine Einspritzöffnung aus, die entweder konisch, in Strömungsrichtung zulaufend ausgebildet ist oder einen zylindrischen und einen konisch zulaufenden Abschnitt aufweist.From the JP 01-300055 Furthermore, an injection valve is known in which a valve member cooperates with a conical valve seat. From the valve seat goes from an injection port, which is either conical, tapering in the flow direction or has a cylindrical and a tapered portion.

Die SU 1740756 A1 zeigt ein Einspritzventil mit einer Einspritzöffnung, die sich aus zwei konischen Abschnitten zusammensetzt. Hierbei verengt sich der erste konische Abschnitt in Strömungsrichtung, während sich der zweite konische Abschnitt erweitert, so dass ein taillierter Einspritzkanal entsteht, der einen engsten Querschnitt aufweist.The SU 1740756 A1 shows an injection valve with an injection opening, which consists of two conical sections. In this case, the first conical section narrows in the direction of flow, while the second conical section expands, so that a waisted injection channel is formed, which has a narrowest cross-section.

Vorteile der ErfindungAdvantages of the invention

Das erfindungsgemäße Kraftstoffeinspritzventil für Brennkraftmaschinen mit den Merkmalen des unabhängigen Anspruches 1 weist demgegenüber den Vorteil auf, dass es bei einer einfach herzustellenden Geometrie des Einspritzkanals zu geringeren Umlenkverlusten beim Eintritt des Kraftstoffs in den Einspritzkanal kommt und damit zu einer guten Zerstäubung und Richtungsstabilität des Einspritzstrahls. Hierzu weist der Einspritzkanal in Strömungsrichtung gesehen einen ersten konischen Abschnitt und einen daran anschließenden zweiten konischen Abschnitt auf. Beide konischen Abschnitte verjüngen sich in Strömungsrichtung, so dass sich der Querschnitt des Einspritzkanals von der Eintrittsöffnung zur Austrittsöffnung verringert.The fuel injection valve according to the invention for internal combustion engines with the features of independent claim 1 has the advantage that it comes with a simple to manufacture geometry of the injection channel to lower deflection losses when the fuel enters the injection channel and thus to a good atomization and directional stability of the injection jet. For this purpose, the injection channel, as seen in the flow direction, has a first conical section and an adjoining second conical section. Both conical sections taper in the flow direction, so that the cross section of the injection channel decreases from the inlet opening to the outlet opening.

Die Unterteilung des Einspritzkanals in zwei separate konische Abschnitte mit unterschiedlichen Öffnungswinkeln bietet darüber hinaus den Vorteil, dass jeder konische Abschnitt eine separate Funktion übernehmen kann, an die er gesondert angepasst ist. So ergibt eine starke Konizität eine hohe Beschleunigung des Kraftstoffs im Einspritzkanal, während eine geringe Konizität hauptsächlich zu einer guten Richtungsstabilität beiträgt, so dass der Einspritzstrahl exakt den vorgesehenen Raumbereich des Brennraums erreicht. Spielen die Umlenkverluste beim Eintritt des Kraftstoffs in den Einspritzkanal nur eine untergeordnete Rolle, so kann frei gewählt werden, welcher der beiden konischen Abschnitte die größere Konizität aufweisen soll.The subdivision of the injection channel into two separate conical sections with different opening angles also offers the advantage that each conical section can assume a separate function, to which it is adapted separately. Thus, a strong conicity gives a high acceleration of the fuel in the injection channel, while a small conicity mainly contributes to a good directional stability, so that the injection jet reaches exactly the intended space region of the combustion chamber. Play the deflection losses when the fuel enters the injection channel only a minor role, it can be freely chosen which of the two conical sections should have the greater taper.

Durch die Unteransprüche sind vorteilhafte Weiterbildungen des Gegenstandes der Erfindung möglich.The subclaims advantageous developments of the subject invention are possible.

In einer vorteilhaften Ausgestaltung des Gegenstandes der Erfindung ist der Öffnungswinkel des ersten konische Abschnitts des Einspritzkanals größer als der Öffnungswinkel des zweiten konischen Abschnitts. Dadurch wird erreicht, dass der Kraftstoff beim Eintritt in den Einspritzkanal eine geringere Richtungsänderung vollführen muss und so an dieser Stelle die Energieverluste vermindert werden. Durch den zweiten konischen Abschnitt, der einen geringeren Öffnungswinkel aufweist, ergibt sich eine gute Richtungsstabilität des Einspritzstrahls bei gleichzeitig guter Zerstäubung. Besonders vorteilhaft ist es hierbei, wenn die Übergangskante zwischen dem ersten konische Abschnitt und dem zweiten konischen Abschnitt gerundet ausgebildet ist. Hierdurch werden weniger Turbulenzen im Einspritzkanal erzeugt, was die Gefahr der Kavitation verringert.In an advantageous embodiment of the subject matter of the invention, the opening angle of the first conical section of the injection channel is greater than the opening angle of the second conical section. This ensures that the fuel when entering the injection channel a less change in direction must perform and thus at this point the energy losses are reduced. By the second conical section, which has a smaller opening angle, there is a good directional stability of the injection jet at the same time good atomization. It is particularly advantageous in this case if the transition edge between the first conical section and the second conical section is rounded. As a result, less turbulence is generated in the injection channel, which reduces the risk of cavitation.

In einer weiteren vorteilhaften Ausgestaltung ist die Länge des ersten konischen Abschnitts größer als die Länge des zweiten konische Abschnitts. Durch einen relativ langen ersten konischen Abschnitt wird der Kraftstoff im Einspritzkanal effektiv beschleunigt, während für die Funktion der Richtungsstabilität des Einspritzstrahls ein kürzerer zweiter konischer Abschnitt genügt. Als besonders vorteilhaft hat es sich dabei erwiesen, wenn die Länge des ersten konischen Abschnitts 3- bis 10-mal größer ist als die Länge des zweiten konischen Abschnitts.In a further advantageous embodiment, the length of the first conical section is greater than the length of the second conical section. By means of a relatively long first conical section, the fuel in the injection channel is effectively accelerated, while a shorter second conical section suffices for the function of the directional stability of the injection jet. It has proven to be particularly advantageous if the length of the first conical section is 3 to 10 times greater than the length of the second conical section.

In einer weiteren vorteilhaften Ausgestaltung der Erfindung weist der erste konische Abschnitt einen kleineren Öffnungswinkel auf als der zweite konische Abschnitt. Sind aufgrund der speziellen Verhältnisse in diesem Einspritzventil die Umlenkverluste beim Eintritt des Kraftstoffs in den Einspritzkanal ohne größere Bedeutung, so kann bei dieser Gestaltung der konischen Abschnitte des Einspritzkanals eine Optimierung in Bezug auf die Richtungsstabilität vorgenommen werden.In a further advantageous embodiment of the invention, the first conical section has a smaller opening angle than the second conical section. If the deflecting losses on entry of the fuel into the injection channel are of little significance due to the special conditions in this injection valve, then in this design of the conical sections of the injection channel an optimization with respect to the directional stability can be undertaken.

Zeichnungdrawing

In der Zeichnung sind verschiedene Ausführungsbeispiele des erfindungsgemäßen Kraftstoffeinspritzventils dargestellt. Es zeigt

Figur 1
einen Längsschnitt durch ein erfindungsgemäßes Kraftstoffeinspritzventil,
Figur 2
eine Vergrößerung von Figur 1 im Bereich eines Einspritzkanals,
Figur 3
eine weitere Darstellung eines Einspritzkanals mit den entsprechenden geometrischen Größen,
Figur 4-5
weitere Ausführungsbeispiele für Einspritzkanäle von erfindungsgemäßen Kraftstoffeinspritzventilen.
In the drawing, various embodiments of the fuel injection valve according to the invention are shown. It shows
FIG. 1
a longitudinal section through a fuel injection valve according to the invention,
FIG. 2
an enlargement of FIG. 1 in the area of an injection channel,
FIG. 3
a further illustration of an injection channel with the corresponding geometric variables,
Figure 4-5
Further embodiments of injection channels of fuel injection valves according to the invention.

Beschreibung der AusführungsbeispieleDescription of the embodiments

In Figur 1 ist ein erfindungsgemäßes Kraftstoffeinspritzventil im Längsschnitt dargestellt. In einem Ventilkörper 1 ist durch eine Sackbohrung 3 ein Druckraum 19 ausgebildet, der in einem mittleren Abschnitt radial erweitert ist, wobei der verbleibende Ventilkörper 1 um den Druckraum 19 eine Wandung bildet. In die radiale Erweiterung des Druckraum 19 mündet ein im Ventilkörper 1 verlaufender Zulaufkanal 25, über den der Druckraum 19 mit Kraftstoff unter hohem Druck befüllt werden kann. Am brennraumseitigen Ende der Sackbohrung 3 ist ein konischer Ventilsitz 9 ausgebildet, von dem wenigstens ein, in der Regel aber mehrere Einspritzkanäle 11 abgehen, die in Einbaulage des Kraftstoffeinspritzventils in den Brennraum der Brennkraftmaschine münden. In der Sackbohrung 3 ist eine kolbenförmige Ventilnadel 5 längsverschiebbar angeordnet. Die Ventilnadel 5 wird in einem brennraumabgewandten, geführten Abschnitt 15 in einem Führungsabschnitt 23 der Sackbohrung 3 dichtend geführt und verjüngt sich dem Ventilsitz 9 zu unter Bildung einer Druckschulter 13, die in der radialen Erweiterung des Druckraums 19 angeordnet ist. Am brennraumseitigen Ende der Ventilnadel 5 ist eine im wesentlichen konische Ventildichtfläche 7 ausgebildet, mit der die Ventilnadel 5 mit dem Ventilsitz 9 zusammenwirkt.In FIG. 1 a fuel injection valve according to the invention is shown in longitudinal section. In a valve body 1, a pressure chamber 19 is formed by a blind bore 3, which is radially expanded in a central portion, wherein the remaining valve body 1 forms a wall around the pressure chamber 19. In the radial extension of the pressure chamber 19 opens a valve body 1 extending inlet channel 25 through which the pressure chamber 19 can be filled with fuel under high pressure. At the combustion chamber end of the blind bore 3, a conical valve seat 9 is formed, from which at least one, but usually several injection channels 11 depart, which open into the mounting position of the fuel injection valve in the combustion chamber of the internal combustion engine. In the blind bore 3, a piston-shaped valve needle 5 is arranged longitudinally displaceable. The valve needle 5 is sealingly guided in a guide section 23 of the blind bore 3 in a guide section 23 remote from the combustion chamber and tapers to the valve seat 9 to form a pressure shoulder 13, which is arranged in the radial extension of the pressure chamber 19. At the combustion chamber end of the valve needle 5 is a substantially conical valve sealing surface 7 is formed, with which the valve needle 5 cooperates with the valve seat 9.

Die Ventilnadel 5 wird an ihrem brennraumabgewandten Ende von einer Schließkraft beaufschlagt, die beispielsweise durch ein in der Zeichnung nicht dargestelltes Federelement erzeugt wird, durch welches die Ventilnadel 5 gegen den Ventilsitz 9 gepresst wird. Der Schließkraft ist eine hydraulische, auf die Druckschulter 13 wirkende Kraft entgegengerichtet. Je nachdem, welche der Kräfte überwiegt, bewegt sich die Ventilnadel 5 entweder vom Ventilsitz 9 weg und gibt die Einspritzkanäle 11 frei, oder die Ventilnadel 5 wird von der Schließkraft gegen den Ventilsitz 9 gepresst, so dass die Einspritzkanäle 11 verschlossen werden. Im geöffneten Zustand der Ventilnadel 5 fließt Kraftstoff aus dem Druckraum 19 zu den Einspritzkanälen 11 und wird von dort in den Brennraum der Brennkraftmaschine eingespritzt. Diese Einspritzung geschieht unter hohem Druck, damit eine gute Zerstäubung des Kraftstoffs und damit eine schadstoffarme Verbrennung erreicht wird.The valve needle 5 is acted upon at its end remote from the combustion chamber by a closing force, which is generated for example by a spring element, not shown in the drawing, through which the valve needle 5 is pressed against the valve seat 9. The closing force is a hydraulic force acting on the pressure shoulder 13 opposing force. Depending on which of the forces predominates, the valve needle 5 either moves away from the valve seat 9 and releases the injection channels 11, or the valve needle 5 is pressed by the closing force against the valve seat 9, so that the injection channels 11 are closed. In the open state of the valve needle 5, fuel flows from the pressure chamber 19 to the injection channels 11 and is injected from there into the combustion chamber of the internal combustion engine. This injection is done under high pressure, so that a good atomization of the fuel and thus a low-emission combustion is achieved.

Figur 2 zeigt eine Vergrößerung von Figur 1 im Bereich des Ventilsitzes 9. Der Einspritzkanal 11 weist eine Eintrittsöffnung 30 auf, die im Ventilsitz 9 angeordnet ist. Die Austrittsöffnung 32 des Einspritzkanals 11 befindet sich auf der Außenseite des Ventilkörpers 1, so dass der Einspritzkanal 11 die Wandung des Druckraums 19 durchdringt. Der Einspritzkanal 11 weist einen ersten konischen Abschnitt 35 und einen zweiten konischen Abschnitt 37 auf, die aneinander grenzen. Am Übergang vom ersten konischen Abschnitt 35 zum zweiten konischen Abschnitt 37 ist einer Übergangskante 38 ausgebildet, die in axialer Richtung des Einspritzkanals 11 gesehen beispielsweise in der Mitte zwischen der Eintrittsöffnung 30 und der Austrittsöffnung 32 angeordnet ist. In Figur 2 ist das Kraftstoffeinspritzventil im geöffneten Zustand dargestellt, das heißt, dass die Ventilnadel 5 vom Ventilsitz 9 abgehoben hat. Hierdurch fließt Kraftstoff unter hohem Druck aus dem Druckraum 19 zwischen der Ventildichtfläche 7 und dem Ventilsitz 9 hindurch zu den Einspritzkanälen 11. Der Kraftstoff fließt durch die Eintrittsöffnung 30 in den Einspritzkanal 11 ein und muss hierbei eine Richtungsänderung vollführen, bei der Energieverluste entstehen, die den effektiven Einspritzdruck senken. Durch die konisch zusammenlaufende Form des ersten konischen Abschnitts 35 wird der Kraftstoffstrom beschleunigt, da sich der Querschnitt in Strömungsrichtung gesehen kontinuierlich verringert. Nach Durchqueren der Übergangskante 38 gelangt der Kraftstoff in den zweiten konischen Abschnitt 37, der einen geringeren Öffnungswinkel aufweist, so dass der Kraftstoff hier zwar weiter beschleunigt wird, jedoch weniger stark als im ersten konischen Abschnitt 35, was für eine gute Einrichtungsstabilität des eingespritzten Kraftstoffstrahls sorgt. FIG. 2 shows an enlargement of FIG. 1 in the region of the valve seat 9. The injection channel 11 has an inlet opening 30, which is arranged in the valve seat 9. The outlet opening 32 of the injection channel 11 is located on the outside of the valve body 1, so that the injection channel 11 penetrates the wall of the pressure chamber 19. The injection channel 11 has a first conical portion 35 and a second conical portion 37 which adjoin one another. At the transition from the first conical portion 35 to the second conical portion 37 of a transition edge 38 is formed, which is seen in the axial direction of the injection channel 11, for example, in the middle between the inlet opening 30 and the outlet opening 32 is arranged. In FIG. 2 the fuel injection valve is shown in the open state, that is, the valve needle 5 from Valve seat 9 has lifted. As a result, fuel flows under high pressure from the pressure chamber 19 between the valve sealing surface 7 and the valve seat 9 through to the injection channels 11. The fuel flows through the inlet opening 30 into the injection channel 11 and in this case has to make a change in direction, resulting in energy losses, the reduce effective injection pressure. Due to the conically converging shape of the first conical section 35, the fuel flow is accelerated, since the cross section decreases continuously in the direction of flow. After passing through the transition edge 38, the fuel passes into the second conical section 37, which has a smaller opening angle, so that the fuel here is further accelerated, but less strong than in the first conical section 35, which ensures good Einrichtungsstabilität the injected fuel jet ,

Figur 3 zeigt noch einmal den Einspritzkanal 11 in einer vergrößerten Darstellung. Der erste konische Abschnitt 35 weist einen Öffnungswinkel α1 auf, der größer ist als der Öffnungswinkels α2 des zweiten konische Abschnitt 37. Die Länge des ersten konischen Abschnitts 35 ist mit a bezeichnet, wobei die Länge a vorzugsweise größer ist als die Länge b des zweiten konischen Abschnitts 37. Je nach Anforderung an die Form des Einspritzstrahls kann das Verhältnis der Längen a, b zueinander beliebig variiert werden. Als besonders vorteilhaft hat es sich erwiesen, wenn der erste konische Abschnitt 35 eine Länge a aufweist, die 3- bis 10-mal größer ist als die Länge b des zweiten konische Abschnitts 37. Die an der Eintrittsöffnung 30 gebildete Einlaufkante 40 ist vorzugsweise gerundet ausgebildet, um Strömungsablösungen in diesem Bereich zu verhindern und die Umlenkverluste zu vermindern. Die an der Austrittsöffnung 32 gebildete Austrittskante 42 kann hingegen gerundet oder scharfkantig ausgebildet sein, was je nach Einspritzdruck und Durchmesser der Austrittsöffnung 32 eine bessere Zerstäubung des Kraftstoffsstrahls bewirkt. FIG. 3 again shows the injection channel 11 in an enlarged view. The first conical section 35 has an opening angle α 1 which is greater than the opening angle α 2 of the second conical section 37. The length of the first conical section 35 is designated by a, the length a preferably being greater than the length b of the first conical section second conical section 37. Depending on the requirement for the shape of the injection jet, the ratio of the lengths a, b to each other can be varied as desired. It has proven to be particularly advantageous if the first conical section 35 has a length a which is 3 to 10 times greater than the length b of the second conical section 37. The inlet edge 40 formed at the inlet opening 30 is preferably rounded to prevent flow separation in this area and to reduce the deflection losses. The exit edge 42 formed at the outlet opening 32, however, may be rounded or sharp-edged, which depends on the injection pressure and diameter the outlet opening 32 causes a better atomization of the fuel jet.

Figur 4 zeigt ein weiteres Ausführungsbeispiel des erfindungsgemäßen Einspritzkanals 11. Der Aufbau des Einspritzkanals 11 entspricht dem von Figur 3, jedoch ist die Übergangskante 38, die am Übergang vom ersten konischen Abschnitts 35 zum zweiten konischen Abschnitt 37 ausgebildet ist, gerundet. Eine solche Rundung der Übergangskante 38 ist besonders dann vorteilhaft, wenn eine große Menge Kraftstoff mit hoher Geschwindigkeit durch den Einspritzkanal 11 fließen soll. Bei einem scharfkantigen Übergang zwischen dem ersten konischen Abschnitt 35 und dem zweiten konischen Abschnitt 37 kann es andernfalls an dieser Stelle zu Strömungsablösungen des Kraftstoffs von der Wand des Einspritzkanals 11 kommen, was sich in einem erhöhten Durchflusswiderstand und damit in einem geringeren effektiven Einspritzdruck bemerkbar macht. FIG. 4 shows a further embodiment of the injection channel 11 according to the invention. The structure of the injection channel 11 corresponds to that of FIG. 3 However, the transition edge 38, which is formed at the transition from the first conical portion 35 to the second conical portion 37, rounded. Such a rounding of the transition edge 38 is particularly advantageous when a large amount of fuel to flow through the injection channel 11 at high speed. In the case of a sharp-edged transition between the first conical section 35 and the second conical section 37, flow separation of the fuel from the wall of the injection channel 11 may otherwise occur at this point, which manifests itself in an increased flow resistance and thus in a lower effective injection pressure.

In Figur 5 ist ein weiteres Ausführungsbeispiel des erfindungsgemäßen Einspritzkanals 11 dargestellt. Das Verhältnis der Öffnungswinkel α1, α2 des ersten konischen Abschnitts 35 und des zweiten konischen Abschnitts 37 sind hier gegenüber den vorherigen Ausführungsbeispielen invertiert, das heißt, dass der Öffnungswinkels α1 des ersten konischen Abschnitts 35 kleiner ist als der Öffnungswinkels α2 des zweiten konischen Abschnitts 37. Auch so erhält man einen Einspritzkanal 11, der eine gute Zerstäubung des Kraftstoffs bei gleichzeitig guter Richtungsstabilität des Einspritzstrahls gewährleistet, jedoch ist hier die Hauptfunktion die einer guten Zerstäubung. Der erste konische Abschnitt 35 ist mit einer geringen Konizität, also mit einem relativ kleinen Öffnungswinkel α1 ausgebildet, so dass der Querschnitt nur langsam in Richtung der Austrittsöffnung 32 abnimmt. Dadurch wird der Druckverlust begrenzt und eine Richtungsstabilität bewirkt. Der zweite konische Abschnitt 37 ist relativ stark konisch, also mit großem Öffnungswinkel α2 ausgebildet, um eine ausreichende Beschleunigung des Kraftstoffs vor dem Austritt aus dem Einspritzkanal 11 zu gewährleisten.In FIG. 5 a further embodiment of the injection channel 11 according to the invention is shown. The ratio of the opening angles α 1 , α 2 of the first conical section 35 and the second conical section 37 are here inverted compared to the previous embodiments, that is, the opening angle α 1 of the first conical section 35 is smaller than the opening angle α 2 of the second Conical section 37. Also, one obtains an injection channel 11, which ensures good atomization of the fuel with good directional stability of the injection jet, but here is the main function of a good atomization. The first conical section 35 is formed with a small conicity, that is to say with a relatively small opening angle α 1 , so that the cross section only decreases slowly in the direction of the outlet opening 32. This limits the pressure loss and causes directional stability. The second conical section 37 is relatively strong conical, ie formed with a large opening angle α 2 , to ensure sufficient acceleration of the fuel before exiting the injection channel 11.

Die Gesamtlänge des Einspritzkanals 11 beträgt, je nach Typ des Kraftstoffeinspritzventils, zwischen 0,5 und 2 mm. Der Durchmesser der Austrittsöffnung 32 beträgt 60 µm bis 150 µm, während der Durchmesser des Eintrittsöffnung 30 wenigstens 20 µm größer ist, vorzugsweise 20 µm bis 60 µm.The total length of the injection channel 11 is, depending on the type of fuel injection valve, between 0.5 and 2 mm. The diameter of the outlet opening 32 is 60 microns to 150 microns, while the diameter of the inlet opening 30 is at least 20 microns larger, preferably 20 microns to 60 microns.

Claims (9)

  1. Fuel injection valve for internal combustion engines having a valve body (1) in which is formed a pressure space (19), in the wall of which pressure space (19) is arranged the inlet opening (30) of at least one injection duct (11), with the injection duct (11) running in the valve body (1) and forming an outlet opening (32) on the outer side of the valve body (1), with the pressure space (19) being formed as a blind bore (3) which runs in the valve body (1) and on the base of which is formed a valve seat (9) in which the inlet opening (30) of the injection duct (11) is arranged, characterized in that the injection duct (11) is divided into two separate conical sections (35; 37), with the first conical section (35) as viewed in the flow direction being adjoined by a second conical section (37), with both conical sections (35; 37) tapering in the flow direction and having different opening angles (α1; α2).
  2. Fuel injection valve according to Claim 1, characterized in that a valve needle (5) is arranged in a longitudinally movable manner in the blind bore (3), which valve needle (5) has, at its combustion-chamber-side end, a valve sealing face (7) by means of which the valve needle (5) interacts with the valve seat (9) and thereby opens and closes the inlet opening (30) of the injection duct (11).
  3. Fuel injection valve according to Claim 1, characterized in that the valve seat (9) forms a conical face.
  4. Fuel injection valve according to Claim 1, characterized in that the opening angle (α1) of the first conical section (35) is greater than the opening angle (α2) of the second conical section (37).
  5. Fuel injection valve according to Claim 1, characterized in that the opening angle (α1) of the first conical section (35) is smaller than the opening angle (α2) of the second conical section (37).
  6. Fuel injection valve according to Claim 1, characterized in that the transition edge (38) formed at the transition from the first conical section (35) to the second conical section (37) is rounded.
  7. Fuel injection valve according to Claim 1, characterized in that the inflow edge (40) formed at the transition from the wall to the inlet opening (30) of the injection duct (11) is of rounded design.
  8. Fuel injection valve according to Claim 1, characterized in that the length (a) of the first conical section (35) is greater than the length (b) of the second conical section (37).
  9. Fuel injection valve according to Claim 8,
    characterized in that the length (a) of the first conical section (35) is 3 to 10 times greater than the length (b) of the second conical section (37).
EP04704544A 2003-04-08 2004-01-23 Fuel injection valve for internal combustion engines Expired - Lifetime EP1623108B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE2003115967 DE10315967A1 (en) 2003-04-08 2003-04-08 Fuel ejecting valve for internal combustion engine, has injecting duct with conical sections, each narrowed along the flow direction and has different opening angles
PCT/DE2004/000101 WO2004092576A1 (en) 2003-04-08 2004-01-23 Fuel injection valve for internal combustion engines

Publications (2)

Publication Number Publication Date
EP1623108A1 EP1623108A1 (en) 2006-02-08
EP1623108B1 true EP1623108B1 (en) 2008-06-11

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EP (1) EP1623108B1 (en)
JP (1) JP2006522887A (en)
CN (1) CN1771390A (en)
DE (2) DE10315967A1 (en)
WO (1) WO2004092576A1 (en)

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DE102006062008A1 (en) * 2006-12-29 2008-07-03 Robert Bosch Gmbh High pressure applying device for air-compressing auto-ignition internal combustion engine, has high pressure channel comprising blind hole, where section hole in region of hole base opens out into blind hole over sectional surface
DE102007051408A1 (en) 2007-10-25 2009-05-28 Prelatec Gmbh Method for drilling holes of defined geometries by means of laser radiation
DE102008041676A1 (en) 2008-08-29 2010-03-04 Robert Bosch Gmbh Fuel injector
EP2187043A1 (en) * 2008-11-14 2010-05-19 Delphi Technologies Holding S.à.r.l. Injection nozzle
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WO2010121767A1 (en) * 2009-04-20 2010-10-28 Prelatec Gmbh Nozzle having at least one spray hole for vaporizing fluids
CN103032232B (en) * 2011-10-10 2015-11-04 中国科学院力学研究所 A kind of engine fuel nozzle
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DE10315967A1 (en) 2004-10-21
EP1623108A1 (en) 2006-02-08
DE502004007360D1 (en) 2008-07-24
WO2004092576A1 (en) 2004-10-28
CN1771390A (en) 2006-05-10
JP2006522887A (en) 2006-10-05

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