EP2753821A1 - Wear-optimised production of conical injection holes - Google Patents

Wear-optimised production of conical injection holes

Info

Publication number
EP2753821A1
EP2753821A1 EP12756065.4A EP12756065A EP2753821A1 EP 2753821 A1 EP2753821 A1 EP 2753821A1 EP 12756065 A EP12756065 A EP 12756065A EP 2753821 A1 EP2753821 A1 EP 2753821A1
Authority
EP
European Patent Office
Prior art keywords
injection
hole
injection nozzle
spray
injection hole
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP12756065.4A
Other languages
German (de)
French (fr)
Inventor
Heinrich Werger
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 EP2753821A1 publication Critical patent/EP2753821A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • 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
    • F02M61/168—Assembling; Disassembling; Manufacturing; Adjusting
    • 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
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/80—Fuel injection apparatus manufacture, repair or assembly
    • F02M2200/8069—Fuel injection apparatus manufacture, repair or assembly involving removal of material from the fuel apparatus, e.g. by punching, hydro-erosion or mechanical operation
    • 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
    • F02M2200/80—Fuel injection apparatus manufacture, repair or assembly
    • F02M2200/8076—Fuel injection apparatus manufacture, repair or assembly involving threaded members
    • 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
    • F02M2200/90—Selection of particular materials
    • F02M2200/9053—Metals
    • F02M2200/9061—Special treatments for modifying the properties of metals used for fuel injection apparatus, e.g. modifying mechanical or electromagnetic properties
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49405—Valve or choke making
    • Y10T29/49426—Valve or choke making including metal shaping and diverse operation

Definitions

  • the invention relates to a method for producing spray holes in fuel injection nozzles for internal combustion engines, in which at least one production step for forming the spray hole and at least one curing step are performed.
  • the invention further relates to a fuel injection nozzle for internal combustion engines, which has at least one injection hole.
  • Fuel injectors consist of the nozzle body and the nozzle needle, both made of high quality steel.
  • the nozzle needle is arranged axially displaceable in the nozzle body and has at its combustion-chamber-side end a conical valve sealing surface. With this conical valve sealing surface, the nozzle needle cooperates with a conical valve seat surface arranged at a closed end of a bore in the nozzle body, wherein a sealing cross section is formed at the contact line between valve sealing surface and valve seat surface.
  • injection holes arranged downstream of the nozzle body are arranged, which, starting from the bore in the nozzle body, open at its outer circumferential surface and protrude into the combustion chamber of the internal combustion engine to be supplied.
  • these spray holes may be formed, for example, conical, with the cross section of the injection holes from a relatively large diameter at the fuel inlet to a relatively small diameter at the fuel outlet uniformly reduced conically.
  • the hole nozzles described above are used in directly injecting diesel engines, especially in common-rail systems. Where they atomize the fuel under very high pressure in a sharp injection jet on the walls of the opposite piston recess.
  • the nozzle body usually has a plurality of injection holes, which form a uniform hole circle on the jacket of a cone inside the nozzle. Depending on the engine, the number of spray holes is between 5 (for cars) and 14 (for large diesel engines). The hole diameter varies between 0.15 mm (for cars) and 0.4 mm (for trucks).
  • the number of spray holes, the spray hole angle and the spray hole size and the flow conditions at the nozzle holes affect the injection jet and its atomization.
  • the respective spray pattern together with other factors such as the injection quantity, the injection pressure, the pressure profile, the combustion chamber geometry, the compression pressure and the compression temperature determines the combustion quality during the combustion of the diesel fuel.
  • the spray holes are exposed to very high mechanical loads.
  • wear mechanisms such as e.g. Cavitation or particle erosion can lead to rapid wear progress and thus to changes in the injection beam shape, the beam propagation or the mass flow rate.
  • these changes can well lead to engine damage and thus to failure.
  • the injection holes can be made by drilling or punching.
  • the shape of injection ports made in this way is almost cylindrical according to the design of the drilling or punching tool.
  • These production methods offer the possibility of giving the injection ports different geometries, such as, for example, conically executed injection holes, which usually decrease in diameter in the flow direction. But there are many more geometries known.
  • the injection hole is formed using at least one abrasive manufacturing process and that the injection nozzle is then subjected at least in the spray hole of a curing treatment, so that the Spray hole surface is cured over its entire axial length.
  • the invention thus relates to the production process in the production of specifically shaped spray holes, So those who by ablative manufacturing processes, such as eroding, lasers or similar. be made.
  • the essence of the invention is now to make the order of the steps of introducing the hole and the curing so as to apply the shaping injection-hole production methods such as erosion or laser each before the responsible for the wear protection heat treatment.
  • the injection holes are thus brought into the so-called soft state and can produce different spray-hole geometries, primarily conical geometries, with the ablation-producing production methods known per se, and nevertheless achieve wear resistance, strength and corrosion resistance in the spray-hole surface. Namely, the hardening treatment is performed only after the molding of the injection hole, so that the spray hole surface can be cured over its entire axial length.
  • the curing treatment is carried out so that the spray hole surface is hardened uniformly over its entire axial length.
  • the injection hole is conical or comprises a conical region.
  • the diameter of the injection hole in the direction of flow decreases steadily.
  • the injection hole is produced by erosion or laser machining.
  • a method for eroding spray holes is described for example in DE 10360080 AI.
  • the curing treatment comprises surface hardening.
  • the hardening treatment comprises in particular a nitriding step or a heat treatment step, in particular case hardening.
  • a particularly efficient procedure provides that the injection hole is formed in the uncured material of the injection nozzle.
  • the inventive method is suitable for the processing of various materials, especially steels.
  • the injection hole is preferably formed in an injection nozzle produced by hot isostatic pressing.
  • a fuel injection nozzle for internal combustion engines which has at least one injection hole, wherein the injection hole has a shape deviating from a cylinder and the area of the spray hole and the spray hole surface is cured over its entire axial length.
  • the spray hole surface is cured uniformly over its entire axial length.
  • the injection hole may advantageously be conical or comprise a conical region.
  • the diameter of the injection hole in the flow direction preferably increases steadily.
  • FIG. 2 a and FIG. 2 b show a detailed view of the region II of FIG. 1, FIG. 2 a showing an embodiment produced according to the invention and FIG. 2 b showing a state of the art Technology produced execution shows.
  • FIG. 1 schematically shows the structure of a common rail injector consisting of a high pressure accumulator 1, a servo valve 2, a throttle plate 3, and an injection nozzle 4.
  • the Ser- voventil 2 closes in the idle state existing in the throttle plate 3 outlet throttle 5. This is in the control chamber 8, which is connected via the high-pressure bore 7 and the inlet throttle 6 to the memory 1, the system pressure, so that the nozzle needle 10 against the nozzle body 9 finished nozzle seat 11 is pressed and the injection holes 12 are closed.
  • the outlet throttle 5 Upon actuation of the servo valve 2, the outlet throttle 5 is released, and the fuel located in the control chamber reduces its pressure in the low-pressure system (not shown) from. At the same time, high-pressure fuel flows via the inlet throttle 6.
  • outlet throttle 5 and inlet throttle 6 are matched to one another such that upon actuation of the servo valve 2, the pressure in the control chamber 8 drops so far that the force acting on the lower part of the nozzle needle 10 pressure in the nozzle chamber 13, the nozzle needle 10 against the pressure in the control chamber 8 and against the force of the nozzle spring 14 presses out of the nozzle seat 11 and the injection holes 12 are released, so that fuel is injected into the combustion chamber 15. After closing the servo valve 2, fuel can no longer flow out of the control chamber 8 via the outlet throttle 5, so that the pressure built up here presses the nozzle needle 10 back into the nozzle seat 11.
  • the injection holes 12 can be seen better.
  • the nozzle needle is not shown for clarity.
  • Denoted at 16 is a near-surface region that has been cured by a curing treatment.
  • the result of a prior art procedure is shown in Fig. 2b.
  • the injection nozzle 4 was first hardened, and only after that the injection holes 12 were inserted so that the injection hole surface 17 was not hardened.
  • the injection holes were first produced. and then made the curing treatment, so that the spray hole surface 17 was also cured.

Landscapes

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

Abstract

The invention relates to a method for producing injection holes (12) in fuel injection nozzles for internal combustion engines, in which the injection hole (12) is formed by means of at least one abrading manufacturing method, wherein the injection nozzle (4) is subsequently subjected to a hardening treatment at least in the region of the injection hole (12), such that the injection hole surface (17) is hardened over the entire axial length thereof.

Description

Verschleißoptimierte Herstellung von konischen Spritzlöchern  Wear-optimized production of conical spray holes
Die Erfindung betrifft ein Verfahren zur Herstellung von Spritzlöchern in Kraftstoffeinspritzdüsen für Verbrennungs- kraftmaschinen, bei welchem wenigstens ein Fertigungsschritt zur Ausbildung des Spritzloches und wenigstens ein Härtungsschritt durchgeführt werden. The invention relates to a method for producing spray holes in fuel injection nozzles for internal combustion engines, in which at least one production step for forming the spray hole and at least one curing step are performed.
Die Erfindung betrifft weiters eine Kraftstoffeinspritzdüse für Verbrennungskraftmaschinen, die wenigstens ein Spritzloch aufweist. The invention further relates to a fuel injection nozzle for internal combustion engines, which has at least one injection hole.
Kraftstoffeinspritzdüsen bestehen aus dem Düsenkörper und der Düsennadel, die beide aus hochwertigem Stahl hergestellt sind. Die Düsennadel ist axial verschiebbar in dem Düsenkörper angeordnet und weist an ihrem brennraumseitigen Ende eine konische Ventildichtfläche auf. Mit dieser konischen Ventildichtfläche wirkt die Düsennadel mit einer an einem geschlossenen Ende einer Bohrung im Düsenkörper angeordneten konischen Ventilsitz- fläche zusammen, wobei an der Berührungslinie zwischen Ventildichtfläche und Ventilsitzfläche ein Dichtquerschnitt gebildet wird. Diesem Dichtguerschnitt sind in KraftstoffStrömungsrichtung stromabwärts Spritzlöcher nachgeordnet, die in der Wand des Düsenkörpers angeordnet sind und die ausgehend von der Boh- rung im Düsenkörper an dessen Außenmantelfläche münden und dabei in den Brennraum der zu versorgenden Brennkraftmaschine ragen. Dabei können diese Spritzlöcher beispielsweise konisch ausgebildet sein, wobei sich der Querschnitt der Spritzlöcher von einem relativ großen Durchmesser am Kraftstoffeintritt zu einem relativ kleinen Durchmesser am Kraftstoffaustritt gleichmäßig konisch verringert. Fuel injectors consist of the nozzle body and the nozzle needle, both made of high quality steel. The nozzle needle is arranged axially displaceable in the nozzle body and has at its combustion-chamber-side end a conical valve sealing surface. With this conical valve sealing surface, the nozzle needle cooperates with a conical valve seat surface arranged at a closed end of a bore in the nozzle body, wherein a sealing cross section is formed at the contact line between valve sealing surface and valve seat surface. In the direction of the fuel flow downstream of said sealing cross section, injection holes arranged downstream of the nozzle body are arranged, which, starting from the bore in the nozzle body, open at its outer circumferential surface and protrude into the combustion chamber of the internal combustion engine to be supplied. In this case, these spray holes may be formed, for example, conical, with the cross section of the injection holes from a relatively large diameter at the fuel inlet to a relatively small diameter at the fuel outlet uniformly reduced conically.
Oben beschriebene Lochdüsen kommen in direkt einspritzenden Dieselmotoren, insbesondere bei Common-Rail-Systemen zum Ein- satz, wo sie den unter sehr hohem Druck befindlichen Kraftstoff in einem scharfen Einspritzstrahl auf die Wände der gegenüberliegenden Kolbenmulde zerstäuben. Der Düsenkörper weist in der Regel mehrere Spritzlöcher auf, die im Inneren der Düse einen gleichmäßigen Lochkreis auf dem Mantel eines Kegels bilden. Je nach Motor liegt die Anzahl der Spritzlöcher zwischen 5 (bei PKWs) bis zu 14 (bei Großdieselmotoren). Der Lochdurchmesser variiert zwischen 0,15 mm (bei PKWs) und 0,4 mm (bei LKWs). Die Spritzlochanzahl, der Spritzlochwinkel und die Spritzlochgröße sowie die Strömungsverhältnisse an den Düsenlöchern beeinflussen den Einspritzstrahl und dessen Zerstäubung. Das jeweilige Spritzbild bestimmt gemeinsam mit anderen Faktoren, wie z.B. der Einspritzmenge, dem Einspritzdruck, dem Druckverlauf, der Brennraumgeometrie, dem Kompressionsdruck und der Kompressions- temperatur die Verbrennungsqualität bei der Verbrennung des Dieselkraftstoffs. The hole nozzles described above are used in directly injecting diesel engines, especially in common-rail systems. Where they atomize the fuel under very high pressure in a sharp injection jet on the walls of the opposite piston recess. The nozzle body usually has a plurality of injection holes, which form a uniform hole circle on the jacket of a cone inside the nozzle. Depending on the engine, the number of spray holes is between 5 (for cars) and 14 (for large diesel engines). The hole diameter varies between 0.15 mm (for cars) and 0.4 mm (for trucks). The number of spray holes, the spray hole angle and the spray hole size and the flow conditions at the nozzle holes affect the injection jet and its atomization. The respective spray pattern, together with other factors such as the injection quantity, the injection pressure, the pressure profile, the combustion chamber geometry, the compression pressure and the compression temperature determines the combustion quality during the combustion of the diesel fuel.
Die Spritzlöcher sind sehr hohen mechanischen Belastungen ausgesetzt. Bei Angriff von Verschleißmechanismen, wie z.B. Kavi- tation oder Partikelerosion kann es zu einem raschen Verschleißfortschritt und dadurch zu Veränderungen der Einspritzstrahlform, der Strahlausbreitung oder auch des Massendurchsatzes kommen. Diese Veränderungen können neben dem Überschreiten von gesetzlichen Emissionslimits durchaus auch zu Motorschäden und damit zum Ausfall führen. Um diese Folgeschäden hintan zu halten, müssen die Einspritzdüsen nach relativ kurzer Laufzeit ausgetauscht und durch neue ersetzt werden. The spray holes are exposed to very high mechanical loads. Upon attack by wear mechanisms, such as e.g. Cavitation or particle erosion can lead to rapid wear progress and thus to changes in the injection beam shape, the beam propagation or the mass flow rate. In addition to exceeding statutory emission limits, these changes can well lead to engine damage and thus to failure. To keep this consequential damage behind, replace the injectors after a relatively short period and replaced by new ones.
Es gibt unterschiedliche Methoden, um die Spritzlöcher in Ein- spritzdüsen einzubringen. Beispielsweise können die Spritzlöcher mittels Bohren oder Stanzen hergestellt werden. Die Form von solcherart hergestellten Spritzlöchern ist entsprechend der Ausbildung des Bohr- oder Stanzwerkzeuges nahezu zylindrisch. Weiters ist es bekannt, die Spritzlöcher durch abtragende Fertigungsverfahren, wie z.B. durch Erodieren oder Lasern herzustellen. Diese Fertigungsverfahren bieten die Möglichkeit, den Spritzlöchern verschiedene Geometrien zu geben, wie beispiels- weise konisch ausgeführte Spritzlöcher, welche meist in Durchflussrichtung im Durchmesser abnehmen. Es sind aber viele weitere Geometrien bekannt. There are different methods for introducing the injection holes in injection nozzles. For example, the injection holes can be made by drilling or punching. The shape of injection ports made in this way is almost cylindrical according to the design of the drilling or punching tool. Furthermore, it is known to produce the injection holes by erosive manufacturing processes, such as erosion or lasers. These production methods offer the possibility of giving the injection ports different geometries, such as, for example, conically executed injection holes, which usually decrease in diameter in the flow direction. But there are many more geometries known.
Grundsätzlich ist es bekannt, den Einspritzdüsenrohkörper einer Wärmebehandlung zu unterziehen, um die Verschleißresistenz, die Festigkeit und dgl. zu erhöhen. Diese Wärmebehandlung ist üblicherweise ein Einsatzhärten oder Nitrieren, d.h. also Wärmebehandlungsverfahren, die den Werkstoff an der Oberfläche zwar hart und verschleißbeständig machen, den Werkstoffkern aller- dings relativ weich aber dafür zäh belassen. Die sich durch den Werkstoffkern erstreckenden Spritzlochbohrungen weisen daher besonders in ihrem mittleren Bereich oft einen unzureichenden Verschleißschutz auf. Die vorliegende Erfindung zielt daher darauf ab, die Verschleißfestigkeit von Spritzlöchern zu erhöhen und damit die Laufzeit der Einspritzdüsen zu verlängern. Gleichzeitig soll die Ausgestaltung der Spritzlochgeometrie bei der Herstellung der Spritzlöcher möglichst keinen Einschränkungen unterliegen. In principle, it is known to subject the injector raw body to a heat treatment in order to increase wear resistance, strength and the like. This heat treatment is usually case-hardening or nitriding, i. That is, heat treatment processes that make the material hard and wear-resistant on the surface, however, leave the core of the material relatively soft but tough. The injection hole bores extending through the core of the material therefore often have inadequate wear protection, especially in their central region. The present invention therefore aims to increase the wear resistance of spray holes and thus to extend the term of the injectors. At the same time the design of the injection hole geometry in the production of the injection holes should be subject as possible no restrictions.
Zur Lösung dieser Aufgabe ist gemäß einem ersten Aspekt der Erfindung bei einem Verfahren der eingangs genannten Art im Wesentlich vorgesehen, dass das Spritzloch mit Hilfe wenigstens eines abtragenden Fertigungsverfahrens ausgebildet wird und dass die Einspritzdüse danach zumindest im Bereich des Spritzloches einer Härtungsbehandlung unterworfen wird, sodass die Spritzlochoberfläche über ihre gesamte axiale Länge gehärtet wird. Die Erfindung bezieht sich somit auf den Fertigungsablauf bei der Herstellung von spezifisch ausgeformten Spritzlöchern, also jenen, die mittels abtragender Fertigungsverfahren, wie beispielsweise Erodieren, Lasern o.ä. gefertigt werden. Der Kern der Erfindung liegt nun darin, die Reihenfolge der Schritte des Einbringens des Loches und des Härtens so zu gestalten, die formgebenden Spritzlochherstellungsverfahren wie z.B. Erodieren oder Lasern jeweils vor der für den Verschleißschutz verantwortlichen Wärmebehandlung anzuwenden. Man bringt die Spritzlöcher somit im so genannten Weichzustand ein und kann mit den an sich bekannten abtragenden Fertigungsverfahren ver- schiedene Spritzlochgeometrien, vordringlich konische Geometrien herstellen und trotzdem die Verschleißbeständigkeit, Festigkeit und Korrosionsbeständigkeit in der Spritzlochoberfläche erreichen. Die Härtungsbehandlung erfolgt nämlich erst nach der Ausformung des Spritzloches, sodass die Spritzlochoberfläche über ihre gesamte axiale Länge gehärtet werden kann. To solve this problem is provided according to a first aspect of the invention in a method of the type mentioned in that the injection hole is formed using at least one abrasive manufacturing process and that the injection nozzle is then subjected at least in the spray hole of a curing treatment, so that the Spray hole surface is cured over its entire axial length. The invention thus relates to the production process in the production of specifically shaped spray holes, So those who by ablative manufacturing processes, such as eroding, lasers or similar. be made. The essence of the invention is now to make the order of the steps of introducing the hole and the curing so as to apply the shaping injection-hole production methods such as erosion or laser each before the responsible for the wear protection heat treatment. The injection holes are thus brought into the so-called soft state and can produce different spray-hole geometries, primarily conical geometries, with the ablation-producing production methods known per se, and nevertheless achieve wear resistance, strength and corrosion resistance in the spray-hole surface. Namely, the hardening treatment is performed only after the molding of the injection hole, so that the spray hole surface can be cured over its entire axial length.
Bevorzugt wird die Härtungsbehandlung so durchgeführt, dass die Spritzlochoberfläche über ihre gesamte axiale Länge gleichmäßig gehärtet wird. Preferably, the curing treatment is carried out so that the spray hole surface is hardened uniformly over its entire axial length.
Wie bereits erwähnt ist bevorzugt vorgesehen, dass das Einspritzloch konisch ausgeführt ist oder einen konischen Bereich umfasst. Insbesondere nimmt der Durchmesser des Spritzlochs in Durchflussrichtung stetig ab. As already mentioned, it is preferably provided that the injection hole is conical or comprises a conical region. In particular, the diameter of the injection hole in the direction of flow decreases steadily.
Mit Vorteil wird das Einspritzloch durch Erodieren oder Laserbearbeitung hergestellt. Ein Verfahren zum Erodieren von Spritzlöchern ist beispielsweise in der DE 10360080 AI beschrieben. Advantageously, the injection hole is produced by erosion or laser machining. A method for eroding spray holes is described for example in DE 10360080 AI.
Bevorzugt umfasst die Härtungsbehandlung eine Oberflächenhärtung. Die Härtungsbehandlung umfasst dabei insbesondere einen Nitrierschritt oder einen Wärmebehandlungsschritt, insbesondere ein Einsatzhärten. Eine besonders effiziente Verfahrensweise sieht vor, dass das Spritzloch im ungehärteten Material der Einspritzdüse ausgebildet wird. Preferably, the curing treatment comprises surface hardening. The hardening treatment comprises in particular a nitriding step or a heat treatment step, in particular case hardening. A particularly efficient procedure provides that the injection hole is formed in the uncured material of the injection nozzle.
Das erfindungsgemäße Verfahren ist für die Bearbeitung von verschiedensten Materialien, insbesondere von Stählen geeignet. Bevorzugt wird das Spritzloch in einer durch heißisostatisches Pressen hergestellten Einspritzdüse ausgebildet. The inventive method is suitable for the processing of various materials, especially steels. The injection hole is preferably formed in an injection nozzle produced by hot isostatic pressing.
Gemäß einem zweiten Aspekt der Erfindung wird eine Kraftstoffeinspritzdüse für Verbrennungskraftmaschinen vorgeschlagen, die wenigstens ein Spritzloch aufweist, wobei das Spritzloch eine von einem Zylinder abweichende Form aufweist und der Bereich des Spritzloches sowie die Spritzlochoberfläche über ihre gesamte axiale Länge gehärtet ist. According to a second aspect of the invention, a fuel injection nozzle for internal combustion engines is proposed, which has at least one injection hole, wherein the injection hole has a shape deviating from a cylinder and the area of the spray hole and the spray hole surface is cured over its entire axial length.
Bevorzugt ist die Spritzlochoberfläche über ihre gesamte axiale Länge gleichmäßig gehärtet. Das Einspritzloch kann mit Vorteil konisch ausgeführt sein oder einen konischen Bereich umfassen. In besonders vorteilhafter Weise, nimmt der Durchmesser des Spritzlochs in Durchflussrichtung bevorzugt stetig zu. Preferably, the spray hole surface is cured uniformly over its entire axial length. The injection hole may advantageously be conical or comprise a conical region. In a particularly advantageous manner, the diameter of the injection hole in the flow direction preferably increases steadily.
Die Erfindung wird nachfolgend anhand eines in der Zeichnung schematisch dargestellten Ausführungsbeispiels näher erläutert. In dieser zeigen Fig.l den grundsätzlichen Aufbau einer Kraftstoffeinspritzdüse eines Common Rail Systems und Fig.2a und Fig.2b eine Detailansicht des Bereichs II der Fig.l, wobei Fig.2a eine erfindungsgemäß hergestellte Ausführung und Fig.2b eine gemäß dem Stand der Technik hergestellte Ausführung zeigt. The invention will be explained in more detail with reference to an embodiment schematically illustrated in the drawing. FIG. 2 a and FIG. 2 b show a detailed view of the region II of FIG. 1, FIG. 2 a showing an embodiment produced according to the invention and FIG. 2 b showing a state of the art Technology produced execution shows.
Fig. 1 zeigt schematisch den Aufbau eines Common-Rail-Injektors bestehend aus einem Hochdruckspeicher 1, einem Servoventil 2 , einer Drosselplatte 3, sowie einer Einspritzdüse 4. Das Ser- voventil 2 verschließt im Ruhezustand die in der Drosselplatte 3 vorhandene Ablaufdrossel 5. Dadurch liegt im Steuerraum 8, der über die Hochdruckbohrung 7 und die Zulaufdrossel 6 mit dem Speicher 1 verbunden ist, der Systemdruck an, sodass die Düsen- nadel 10 gegen den im Düsenkörper 9 gefertigten Düsensitz 11 gedrückt und die Spritzlöcher 12 verschlossen werden. Bei Betätigung des Servoventils 2 wird die Ablaufdrossel 5 frei gegeben, und der im Steuerraum befindliche Kraftstoff baut seinen Druck in das Niederdrucksystem (nicht dargestellt) ab. Gleich- zeitig fließt über die Zulaufdrossel 6 unter Hochdruck stehender Kraftstoff nach. Die effektiven Durchflussquerschnitte von Ablaufdrossel 5 und Zulaufdrossel 6 sind dabei so aufeinander abgestimmt, dass bei Betätigung des Servoventils 2 der Druck im Steuerraum 8 so weit absinkt, dass der auf den unteren Teil der Düsennadel 10 wirkende Druck im Düsenraum 13 die Düsennadel 10 gegen den Druck im Steuerraum 8 und gegen die Kraft der Düsenfeder 14 aus dem Düsensitz 11 drückt und die Spritzlöcher 12 frei gegeben werden, sodass Kraftstoff in den Brennraum 15 eingespritzt wird. Nach Schließen des Servoventils 2 kann kein Kraftstoff mehr über die Ablaufdrossel 5 aus dem Steuerraum 8 abfließen, sodass der sich hier aufbauende Druck die Düsennadel 10 wieder in den Düsensitz 11 drückt. 1 schematically shows the structure of a common rail injector consisting of a high pressure accumulator 1, a servo valve 2, a throttle plate 3, and an injection nozzle 4. The Ser- voventil 2 closes in the idle state existing in the throttle plate 3 outlet throttle 5. This is in the control chamber 8, which is connected via the high-pressure bore 7 and the inlet throttle 6 to the memory 1, the system pressure, so that the nozzle needle 10 against the nozzle body 9 finished nozzle seat 11 is pressed and the injection holes 12 are closed. Upon actuation of the servo valve 2, the outlet throttle 5 is released, and the fuel located in the control chamber reduces its pressure in the low-pressure system (not shown) from. At the same time, high-pressure fuel flows via the inlet throttle 6. The effective flow cross sections of outlet throttle 5 and inlet throttle 6 are matched to one another such that upon actuation of the servo valve 2, the pressure in the control chamber 8 drops so far that the force acting on the lower part of the nozzle needle 10 pressure in the nozzle chamber 13, the nozzle needle 10 against the pressure in the control chamber 8 and against the force of the nozzle spring 14 presses out of the nozzle seat 11 and the injection holes 12 are released, so that fuel is injected into the combustion chamber 15. After closing the servo valve 2, fuel can no longer flow out of the control chamber 8 via the outlet throttle 5, so that the pressure built up here presses the nozzle needle 10 back into the nozzle seat 11.
In der Detailansicht gemäß den Fig. 2a und 2b sind die Spritz- löcher 12 besser ersichtlich. Die Düsennadel ist der Übersichtlichkeit halber nicht dargestellt. Mit 16 ist ein oberflächennaher Bereich bezeichnet, der auf Grund einer Härtungsbehandlung gehärtet wurde. Das Ergebnis einer Verfahrensweise gemäß dem Stand der Technik ist in Fig.2b gezeigt. Die Einspritzdüse 4 wurde zuerst gehärtet und erst danach wurden die Spritzlöcher 12 eingebracht, sodass die Spritzlochoberfläche 17 nicht gehärtet wurde. Bei der erfindungsgemäßen Verfahrensweise hingegen, dargestellt in Fig.2a, wurden zuerst die Spritzlöcher herge- stellt und danach die Härtungsbehandlung vorgenommen, sodass auch die Spritzlochoberfläche 17 mitgehärtet wurde. In the detail view according to FIGS. 2 a and 2 b, the injection holes 12 can be seen better. The nozzle needle is not shown for clarity. Denoted at 16 is a near-surface region that has been cured by a curing treatment. The result of a prior art procedure is shown in Fig. 2b. The injection nozzle 4 was first hardened, and only after that the injection holes 12 were inserted so that the injection hole surface 17 was not hardened. In contrast, in the method according to the invention shown in FIG. 2a, the injection holes were first produced. and then made the curing treatment, so that the spray hole surface 17 was also cured.

Claims

Patentansprüche : Claims:
1. Verfahren zur Herstellung von Spritzlöchern in Kraftstoffeinspritzdüsen für Verbrennungskraftmaschinen, bei welchem wenigstens ein Fertigungsschritt zur Ausbildung des Spritzloches und wenigstens ein Härtungsschritt durchgeführt werden, dadurch gekennzeichnet, dass das Spritzloch (12) mit Hilfe wenigstens eines abtragenden Fertigungsverfahrens ausgebildet wird und dass die Einspritzdüse (4) danach zumindest im Bereich des Spritzloches (12) einer Härtungsbehandlung unterworfen wird, sodass die Spritzlochoberfläche (17) über ihre gesamte axiale Länge gehärtet wird. 1. A method for producing spray holes in fuel injection nozzles for internal combustion engines, wherein at least one manufacturing step for forming the spray hole and at least one curing step are performed, characterized in that the injection hole (12) is formed by means of at least one abrasive manufacturing process and that the injection nozzle ( 4) is then subjected to a hardening treatment at least in the region of the spray hole (12), so that the spray hole surface (17) is hardened over its entire axial length.
2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass die Spritzlochoberfläche (17) über ihre gesamte axiale Länge gleichmäßig gehärtet wird. 2. The method according to claim 1, characterized in that the spray hole surface (17) is hardened uniformly over its entire axial length.
3. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass das Spritzloch (12) konisch ausgeführt ist oder einen ko- nischen Bereich umfasst. 3. The method according to claim 1 or 2, characterized in that the injection hole (12) is conical or comprises a conical region.
4. Verfahren nach Anspruch 3, dadurch gekennzeichnet, dass der Durchmesser des Spritzlochs (12) in Durchflussrichtung bevorzugt stetig abnimmt. 4. The method according to claim 3, characterized in that the diameter of the injection hole (12) in the flow direction preferably decreases steadily.
5. Verfahren nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, dass das Spritzloch (12) durch Erodieren oder Laserbearbeitung hergestellt wird. 5. The method according to any one of claims 1 to 4, characterized in that the injection hole (12) is produced by erosion or laser machining.
6. Verfahren nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, dass die Härtungsbehandlung eine Oberflächenhär- tung umfasst. 6. The method according to any one of claims 1 to 5, characterized in that the hardening treatment comprises a surface hardening.
7. Verfahren nach Anspruch 6, dadurch gekennzeichnet, dass die Härtungsbehandlung einen Nitrierschritt oder einen Wärmebehandlungsschritt, insbesondere ein Einsatzhärten umfasst. 7. The method according to claim 6, characterized in that the hardening treatment comprises a nitriding step or a heat treatment step, in particular a case hardening.
8. Verfahren nach einem der Ansprüche 1 bis 7, dadurch gekennzeichnet, dass das Spritzloch (12) im ungehärteten Material der Einspritzdüse (4) ausgebildet wird. 8. The method according to any one of claims 1 to 7, characterized in that the injection hole (12) in the uncured material of the injection nozzle (4) is formed.
9. Verfahren nach einem der Ansprüche 1 bis 8, dadurch ge- kennzeichnet, dass das Spritzloch (12) in einer durch heiß- isostatisches Pressen hergestellten Einspritzdüse (4) ausgebildet wird. 9. The method according to any one of claims 1 to 8, character- ized in that the injection hole (12) is formed in an injection nozzle (4) produced by hot isostatic pressing.
10. Kraftstoffeinspritzdüse für Verbrennungskraftmaschinen, die wenigstens ein Spritzloch (12) aufweist, dadurch gekennzeichnet, dass das Spritzloch (12) eine von einem Zylinder abweichende Form aufweist und dass der Bereich des Spritzloches (12) sowie die Spritzlochoberfläche (17) über ihre gesamte axiale Länge gehärtet ist. 10. Fuel injection nozzle for internal combustion engines, which has at least one injection hole (12), characterized in that the injection hole (12) has a different shape from a cylinder and that the area of the spray hole (12) and the spray hole surface (17) over its entire axial Length is cured.
11. Einspritzdüse nach Anspruch 10, dadurch gekennzeichnet, dass die Spritzlochoberfläche (17) über ihre gesamte axiale Länge gleichmäßig gehärtet ist. 11. Injection nozzle according to claim 10, characterized in that the spray hole surface (17) is hardened uniformly over its entire axial length.
12. Einspritzdüse nach Anspruch 10 oder 11, dadurch gekennzeichnet, dass das Spritzloch (12) konisch ausgeführt ist oder einen konischen Bereich umfasst. 12. Injection nozzle according to claim 10 or 11, characterized in that the injection hole (12) is conical or comprises a conical region.
13. Einspritzdüse nach Anspruch 12, dadurch gekennzeichnet, dass der Durchmesser des Spritzlochs (12) in Durchflussrichtung bevorzugt stetig zunimmt. 13. Injection nozzle according to claim 12, characterized in that the diameter of the injection hole (12) in the flow direction preferably increases steadily.
14. Einspritzdüse nach einem der Ansprüche 10 bis 13, dadurch gekennzeichnet, dass die Einspritzdüse (4) eine durch heiß- isostatisches Pressen hergestellte Einspritzdüse (4) ist. 14. Injection nozzle according to one of claims 10 to 13, characterized in that the injection nozzle (4) is an injection nozzle (4) produced by hot isostatic pressing.
EP12756065.4A 2011-09-06 2012-08-28 Wear-optimised production of conical injection holes Withdrawn EP2753821A1 (en)

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ATA1269/2011A AT511880B1 (en) 2011-09-06 2011-09-06 WEAR-OPTIMIZED MANUFACTURE OF TAPPY SPRAY HOLES
PCT/AT2012/000223 WO2013033737A1 (en) 2011-09-06 2012-08-28 Wear-optimised production of conical injection holes

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EP (1) EP2753821A1 (en)
JP (1) JP2014525535A (en)
KR (1) KR20140062482A (en)
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AT (1) AT511880B1 (en)
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KR20140062482A (en) 2014-05-23
WO2013033737A1 (en) 2013-03-14
US20150083829A1 (en) 2015-03-26
JP2014525535A (en) 2014-09-29
CN103764999A (en) 2014-04-30
AT511880A1 (en) 2013-03-15
AT511880B1 (en) 2013-12-15

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