EP0553479A1 - Fuel injector for internal combustion engine - Google Patents

Fuel injector for internal combustion engine Download PDF

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Publication number
EP0553479A1
EP0553479A1 EP92121667A EP92121667A EP0553479A1 EP 0553479 A1 EP0553479 A1 EP 0553479A1 EP 92121667 A EP92121667 A EP 92121667A EP 92121667 A EP92121667 A EP 92121667A EP 0553479 A1 EP0553479 A1 EP 0553479A1
Authority
EP
European Patent Office
Prior art keywords
spray holes
internal combustion
edge
rounding
spray 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Withdrawn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
EP92121667A
Other languages
German (de)
French (fr)
Inventor
Edgar Dipl.-Ing. Goetz
Klaus Dahlmeier
Wilhelm Dipl.-Ing. Christ
Bernhard Dipl.-Ing. Lucas
Friedrich Dipl.-Ing. Boecking
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 EP0553479A1 publication Critical patent/EP0553479A1/en
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B1/00—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means
    • B05B1/34—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means designed to influence the nature of flow of the liquid or other fluent material, e.g. to produce swirl
    • B05B1/3402—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means designed to influence the nature of flow of the liquid or other fluent material, e.g. to produce swirl to avoid or to reduce turbulencies, e.g. comprising fluid flow straightening means

Definitions

  • the invention is based on a fuel injection nozzle for internal combustion engines according to the preamble of claim 1.
  • the spray holes have a cylindrical shape with a sharp outlet edge.
  • the edge surrounding the spray hole inlet is rounded.
  • wear occurs due to the narrowing in the course of operation in the outlet of the spray holes in such a way that tiny particles thrown against the edge by shock waves cause deformation of the edge.
  • the free flow cross section and thus the spray jet characteristic decrease over the course of the operating time, so that the injection nozzle is no longer optimally matched to the internal combustion engine.
  • the fuel injector according to the invention with the characterizing features of claim 1 has the advantage that a deformation during the operating period is anticipated by the rounding at the edge of the spray hole outlet, so that the flow through the the entire running time of the injection nozzle remains constant. Thanks to the rounded spray hole outlet edges, the distribution of the fuel jet pulse in the combustion chamber is also uniform and the atomization quality of the jet is improved. If the outlet edges are very smooth, coking of the spray holes and the adjacent areas is also reduced. Furthermore, the notch effect is reduced by the rounding at the spray hole outlet edges, so that the strength of the tip of the nozzle body receiving the spray holes is increased.
  • the rounding at the edge of the outlet is preferably produced hydroerosively with a suspension of a liquid carrier medium and grinding particles, which is pumped from the outside in through the spray hole.
  • a nozzle body 1 has in the region of its combustion chamber end a conical valve seat 2, with which a closing cone 3 of a spring-loaded valve needle 4, which is displaceably guided in the nozzle body 1, cooperates.
  • the inlet 11 of the spray holes 10 The dome 5 can also lie in the region of the valve seat 2 and, depending on the design of the combustion chamber of the internal combustion engine, one or more spray holes with different spray directions can be arranged with respect to the longitudinal axis of the injection nozzle.
  • the spray holes 10, which shape the fuel flowing through into a jet have essentially the shape of a cylinder with a constant diameter. They have a diameter of 0.1 to 0.3 mm for direct injection.
  • the edge 15 surrounding the outlet 12 is rounded convexly.
  • the curve preferably has a radius in the range from 0.03 to 0.06 mm.
  • the rounding is produced on the edge 15 of the outlet 12 of the spray holes 10 hydroerosively with a suspension of a liquid carrier medium and abrasive particles.
  • the suspension is pumped through the spray holes 10 from the outlet 12 into the blind hole 10.
  • the degree of rounding can be determined either by the processing time and / or by the flow rate. The removal of material in the spray holes by the flowing through suspension is negligible.

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

Abstract

A fuel injector for internal combustion engines has a nozzle body (1) with spray holes (10) opening into the combustion space. In order to keep the shape of the jet shaped by the spray holes constant over the entire operating time of the injector, the edge (15) at the outlet of the spray holes is rounded, the radius of the rounding is preferably in a range of from 0.03 to 0.06 mm. The rounding is produced by pumping an abrasive suspension through the spray holes from the outside inwards. <IMAGE>

Description

Stand der TechnikState of the art

Die Erfindung geht aus von einer Kraftstoffeinspritsdüse für Brennkraftmaschinen nach der Gattung des Anspruchs 1. Bei bekannten Einspritzdüsen dieser Art, sogenannten Lochdüsen, haben die Spritzlöcher eine zylindrische Form mit scharfer Auslaßkante. Bei manchen Einspritsdüsen ist, um die Strömung zu verbessern, die den Spritzlocheinlauf umgebende Kante gerundet. Bei den bekannten Lochdüsen tritt im Laufe des Betriebs im Auslauf der Spritzlöcher Verschleiß durch Verengung in der Weise auf, daß durch Stoßwellen gegen die Kante geschleuderte kleinste Teilchen eine Verformung der Kante bewirken. Aufgrund dieses Betriebsverschleißes verkleinert sich im Laufe der Betriebsdauer der freie Durchflußquerschnitt und damit die Spritzstrahlcharakteristik, so daß die Einspritzdüse nicht mehr optimal auf die Brennkraftmaschine abgestimmt ist.The invention is based on a fuel injection nozzle for internal combustion engines according to the preamble of claim 1. In known injection nozzles of this type, so-called hole nozzles, the spray holes have a cylindrical shape with a sharp outlet edge. In some injection nozzles, in order to improve the flow, the edge surrounding the spray hole inlet is rounded. In the known perforated nozzles, wear occurs due to the narrowing in the course of operation in the outlet of the spray holes in such a way that tiny particles thrown against the edge by shock waves cause deformation of the edge. As a result of this operational wear, the free flow cross section and thus the spray jet characteristic decrease over the course of the operating time, so that the injection nozzle is no longer optimally matched to the internal combustion engine.

Vorteile der ErfindungAdvantages of the invention

Die erfindungsgemäße Kraftstoffeinspritzdüse mit den kennzeichnenden Merkmalen des Anspruchs 1 hat den Vorteil, daß durch die Rundung an der Kante des Spritzlochauslaufs eine Verformung während der Betriebsdauer vorweggenommen wird, so daß der Durchfluß über die gesamte Laufzeit der Einspritzdüse konstant bleibt. Durch die gerundeten Spritzlochauslaufkanten ist außerdem die Verteilung des Kraftstoffstrahlimpulses im Brennraum gleichmäßig und die Zerstäubungsgüte des Strahls wird verbessert. Bei einer sehr glatten Rundung der Auslaufkanten wird auch eine Verkokung der Spritzlöcher und der angrenzenden Bereiche herabgesetzt. Ferner wird durch die Rundung an den Spritzlochauslaufkanten die Kerbwirkung vermindert, so daß die Festigkeit der die Spritzlöcher aufnehmenden Kuppe des Düsenkörpers erhöht ist.The fuel injector according to the invention with the characterizing features of claim 1 has the advantage that a deformation during the operating period is anticipated by the rounding at the edge of the spray hole outlet, so that the flow through the the entire running time of the injection nozzle remains constant. Thanks to the rounded spray hole outlet edges, the distribution of the fuel jet pulse in the combustion chamber is also uniform and the atomization quality of the jet is improved. If the outlet edges are very smooth, coking of the spray holes and the adjacent areas is also reduced. Furthermore, the notch effect is reduced by the rounding at the spray hole outlet edges, so that the strength of the tip of the nozzle body receiving the spray holes is increased.

Vorzugsweise wird die Rundung an der Kante des Auslaufs hydroerosiv mit einer Suspension aus einem flüssigen Trägermedium und Schleifpartikeln hergestellt, die von außen nach innen durch das Spritzloch gepumpt wird.The rounding at the edge of the outlet is preferably produced hydroerosively with a suspension of a liquid carrier medium and grinding particles, which is pumped from the outside in through the spray hole.

Zeichnungdrawing

Ein Ausführungsbeispiel der Erfindung ist in der Zeichnung dargestellt, die den brennraumseitigen Teil einer Kraftstoffeinspritzdüse zeigt, und wird im folgenden näher beschrieben.An embodiment of the invention is shown in the drawing, which shows the combustion chamber side part of a fuel injector, and will be described in more detail below.

Beschreibung des AusführungsbeispielsDescription of the embodiment

Ein Düsenkörper 1 hat im Bereich seines brennraumseitigen Endes einen konischen Ventilsitz 2, mit dem ein Schließkonus 3 einer im Düsenkörper 1 verschiebbar geführten, federbelasteten Ventilnadel 4 zusammenwirkt. In Kraftstoffströmungsrichtung unterhalb des Ventilsitzes 2 schließt sich in einer Kuppe 5 des Düsenkörpers 1 ein Sackloch 6 an, von dem aus ein oder mehrere die Wand der Kuppe 5 durchdringende Spritzlöcher 10 abgehen. Der Einlauf 11 der Spritzlöcher 10 in der Kuppe 5 kann auch im Bereich des Ventilsitzes 2 liegen und je nach Gestaltung des Brennraums der Brennkraftmaschine können ein oder mehrere Spritzlöcher mit verschiedenen Spritzrichtungen zur Längsachse der Einspritzdüse angeordnet sein.A nozzle body 1 has in the region of its combustion chamber end a conical valve seat 2, with which a closing cone 3 of a spring-loaded valve needle 4, which is displaceably guided in the nozzle body 1, cooperates. In the fuel flow direction below the valve seat 2 there is a blind hole 6 in a dome 5 of the nozzle body 1, from which one or more spray holes 10 penetrate the wall of the dome 5. The inlet 11 of the spray holes 10 The dome 5 can also lie in the region of the valve seat 2 and, depending on the design of the combustion chamber of the internal combustion engine, one or more spray holes with different spray directions can be arranged with respect to the longitudinal axis of the injection nozzle.

Die Spritzlöcher 10, die den durchströmenden Kraftstoff zu einem Strahl formen, haben im wesentlichen die Form eines Zylinders mit konstantem Duchmesser. Für Direkteinspritzung haben sie einen Durchmesser von 0,1 bis 0,3 mm. Um eine über die gesamte Laufzeit der Einspritzdüse gleichförmige Beeinflussung der aus den Spritzlöchern 10 austretenden Kraftstoffstrahlen zu bewirken, ist die den Auslaß 12 umgebende Kante 15 konvex gerundet. Die Rundung hat vorzugsweise einen Radius im Bereich von 0,03 bis 0,06 mm. Hergestellt wird die Rundung an der Kante 15 des Auslaufs 12 der Spritzlöcher 10 hydroerosiv mit einer Suspension aus einem flüssigen Trägermedium und Schleifpartikeln. Die Suspension wird durch die Spritzlöcher 10 vom Auslauf 12 her in das Sackloch 10 gepumpt. Der Grad der Rundung kann entweder durch die Bearbeitungszeit und/oder durch die Durchflußmenge bestimmt werden. Der Abtrag von Material in den Spritzlöchern durch die durchströmende Suspension ist vernachlässigbar.The spray holes 10, which shape the fuel flowing through into a jet, have essentially the shape of a cylinder with a constant diameter. They have a diameter of 0.1 to 0.3 mm for direct injection. In order to influence the fuel jets emerging from the spray holes 10 uniformly over the entire running time of the injection nozzle, the edge 15 surrounding the outlet 12 is rounded convexly. The curve preferably has a radius in the range from 0.03 to 0.06 mm. The rounding is produced on the edge 15 of the outlet 12 of the spray holes 10 hydroerosively with a suspension of a liquid carrier medium and abrasive particles. The suspension is pumped through the spray holes 10 from the outlet 12 into the blind hole 10. The degree of rounding can be determined either by the processing time and / or by the flow rate. The removal of material in the spray holes by the flowing through suspension is negligible.

Claims (3)

Kraftstoffeinspritzdüse für Brennkraftmaschinen mit einem Düsenkörper, in dem eine verschiebbar geführte Ventilnadel mit einem Ventilsitz zusammenwirkt, an den sich mindestens ein den Düsenkörper durchdringendes Spritzloch anschließt, dadurch gekennzeichnet, daß die den Auslauf (12) des Spritzlochs (10) umgebende Kante (15) konvex gerundet ist.Fuel injection nozzle for internal combustion engines with a nozzle body in which a displaceably guided valve needle interacts with a valve seat, to which at least one spray hole penetrating the nozzle body is connected, characterized in that the edge (15) surrounding the outlet (12) of the spray hole (10) is convex is rounded. Kraftstoffeinspritzdüse nach Anspruch 1, dadurch gekennzeichnet, daß die Kante (15) mit einem Radius im Bereich von 0,03 bis 0,06 mm gerundet ist.Fuel injection nozzle according to Claim 1, characterized in that the edge (15) is rounded with a radius in the range from 0.03 to 0.06 mm. Verfahren zum Herstellen einer Einspritzdüse mit wenigstens einem Spritzloch nach einem der Ansprüche 1 oder 2, dadurch gekennzeichnet, daß die Rundung (17) hydroerosiv mit einer Suspension aus flüssigem Trägermedium und darin suspendierten Schleifpartikeln geformt wird, die von außen nach innen durch das Spritzloch (10) gepumpt wird.Method for producing an injection nozzle with at least one spray hole according to one of Claims 1 or 2, characterized in that the rounding (17) is formed hydroerosively with a suspension of liquid carrier medium and abrasive particles suspended therein which passes through the spray hole (10 ) is pumped.
EP92121667A 1992-01-31 1992-12-19 Fuel injector for internal combustion engine Withdrawn EP0553479A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4202752 1992-01-31
DE4202752A DE4202752A1 (en) 1992-01-31 1992-01-31 FUEL INJECTION NOZZLE FOR INTERNAL COMBUSTION ENGINES

Publications (1)

Publication Number Publication Date
EP0553479A1 true EP0553479A1 (en) 1993-08-04

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ID=6450679

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Application Number Title Priority Date Filing Date
EP92121667A Withdrawn EP0553479A1 (en) 1992-01-31 1992-12-19 Fuel injector for internal combustion engine

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EP (1) EP0553479A1 (en)
JP (1) JPH05296123A (en)
DE (1) DE4202752A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2796104A1 (en) * 1999-07-08 2001-01-12 Siemens Ag INJECTOR BODY HAVING OPTIMAL INJECTION ORIFICE GEOMETRY AND METHOD FOR BENDING THE EDGES OF SUCH AN ORIFICE
WO2002063161A1 (en) * 2001-02-08 2002-08-15 Siemens Aktiengesellschaft Fuel injection nozzle for an internal combustion engine
EP1508689A1 (en) * 1999-08-11 2005-02-23 Robert Bosch Gmbh Fuel injection valve
WO2013117978A1 (en) * 2012-02-07 2013-08-15 Robert Bosch Gmbh Injection nozzle for injecting media into the combustion chamber of an internal combustion engine

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB0712403D0 (en) 2007-06-26 2007-08-01 Delphi Tech Inc A Spray Hole Profile
JP5786875B2 (en) 2013-02-05 2015-09-30 株式会社デンソー Fuel injection nozzle

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE285330C (en) *
FR2352957A1 (en) * 1976-05-26 1977-12-23 Sulzer Ag INTERNAL COMBUSTION ENGINE FUEL INJECTION VALVE JET
EP0446165A1 (en) * 1990-03-06 1991-09-11 Ail Corporation Method and apparatus for electrochemical machining of spray holes in fuel injection nozzles

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3306078A1 (en) * 1983-02-22 1984-08-23 Robert Bosch Gmbh, 7000 Stuttgart FUEL INJECTION NOZZLE FOR INTERNAL COMBUSTION ENGINES

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE285330C (en) *
FR2352957A1 (en) * 1976-05-26 1977-12-23 Sulzer Ag INTERNAL COMBUSTION ENGINE FUEL INJECTION VALVE JET
EP0446165A1 (en) * 1990-03-06 1991-09-11 Ail Corporation Method and apparatus for electrochemical machining of spray holes in fuel injection nozzles

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2796104A1 (en) * 1999-07-08 2001-01-12 Siemens Ag INJECTOR BODY HAVING OPTIMAL INJECTION ORIFICE GEOMETRY AND METHOD FOR BENDING THE EDGES OF SUCH AN ORIFICE
EP1508689A1 (en) * 1999-08-11 2005-02-23 Robert Bosch Gmbh Fuel injection valve
WO2002063161A1 (en) * 2001-02-08 2002-08-15 Siemens Aktiengesellschaft Fuel injection nozzle for an internal combustion engine
WO2013117978A1 (en) * 2012-02-07 2013-08-15 Robert Bosch Gmbh Injection nozzle for injecting media into the combustion chamber of an internal combustion engine

Also Published As

Publication number Publication date
DE4202752A1 (en) 1993-08-05
JPH05296123A (en) 1993-11-09

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