WO2015124340A1 - Injecteur de carburant - Google Patents

Injecteur de carburant Download PDF

Info

Publication number
WO2015124340A1
WO2015124340A1 PCT/EP2015/050841 EP2015050841W WO2015124340A1 WO 2015124340 A1 WO2015124340 A1 WO 2015124340A1 EP 2015050841 W EP2015050841 W EP 2015050841W WO 2015124340 A1 WO2015124340 A1 WO 2015124340A1
Authority
WO
WIPO (PCT)
Prior art keywords
needle
control chamber
restriction
conduit
fuel injector
Prior art date
Application number
PCT/EP2015/050841
Other languages
English (en)
Inventor
Andrew Male
Original Assignee
Delphi International Operations Luxembourg S.À R.L.
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 Delphi International Operations Luxembourg S.À R.L. filed Critical Delphi International Operations Luxembourg S.À R.L.
Publication of WO2015124340A1 publication Critical patent/WO2015124340A1/fr

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
    • F02M61/04—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00 having valves, e.g. having a plurality of valves in series
    • F02M61/042—The valves being provided with fuel passages
    • 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
    • F02M47/00—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure
    • F02M47/02—Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure of accumulator-injector type, i.e. having fuel pressure of accumulator tending to open, and fuel pressure in other chamber tending to close, injection valves and having means for periodically releasing that closing pressure
    • F02M47/027—Electrically actuated valves draining the chamber to release the closing pressure
    • 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
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0012—Valves
    • F02M63/007—Details not provided for in, or of interest apart from, the apparatus of the groups F02M63/0014 - F02M63/0059
    • F02M63/0078—Valve member details, e.g. special shape, hollow or fuel passages in the valve member
    • 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
    • F02M2200/28—Details of throttles in fuel-injection apparatus

Definitions

  • the present invention relates to a fuel injector and more particularly to the arrangement to control the displacement of the valve needle.
  • statically leak less injectors are commonly used. These injectors use simple unbalanced nozzle control valves to control pressure acting on the nozzle control piston.
  • the control valve has no stem through which high pressure fuel can leak and therefore an unbalanced nozzle control valve does not leak when the injector is idle and not injecting.
  • a fuel injector for injecting fuel into a combustion chamber of an internal combustion engine.
  • a supply channel arranged in the body of the injector is adapted to flow high pressure fuel from an inlet to at least one injection hole.
  • the injector comprises a control valve hydraulically controlling the displacements of a valve needle arranged within an axial main bore of the body.
  • the needle reciprocally displaces between a closed position, wherein fuel injection is prevented and, a fully open position wherein fuel injection through the injection holes is enabled.
  • the main bore axially extends from a pointy tip provided with the injection holes to an upper extremity forming a control chamber in which protrudes the upper extremity of the valve needle.
  • the control chamber is in fluid communication with the high pressure supply channel via a supply conduit and with, a low pressure return channel via another conduit controlled by the control valve.
  • the needle is provided with an internal conduit extending between its upper face and its side wall where it opens in the control chamber.
  • the internal conduit comprises a diametral through hole having its both ends diametrally opposed, each end opening in the control chamber and, an axial hole extending from the through hole to the upper face of the needle.
  • the supply conduit is provided with an inlet orifice creating a first restriction.
  • the internal conduit arranged in the needle is provided with a second restriction. That has a smaller cross section than the first restriction.
  • the section of the second restriction is between 75% and 25% of the section of the first restriction and, preferably half of the section of the first restriction.
  • the control chamber has a transversal ceiling in which is arranged another recess, the central conduit opening in said recess.
  • Figures 1 is a schematic axial section of the control valve of a fuel injector as per the invention, the valve being in a closed position.
  • Figure 2 is the injector of figure 1 in a fully open position.
  • the injector 10 extends along a main axis A.
  • Its body 12 comprises, fixedly arranged from top to bottom, an upper actuator body 14, a valve plate 16 and a lower nozzle body 18.
  • a supply channel 20 extends downwardly from a top inlet arranged in the actuator body 14 then, through the valve plate 16 and in the nozzle body 18. High pressure fuel flows in said channel 20 to be ultimately injected in a combustion chamber of an internal combustion engine.
  • the upper body 14 is provided with an upper cylindrical space 22 from which downwardly extends an upper valve bore 24 opening in an enlarged cylindrical recess 26. In said spaces, the upper body 14 receives an upper valve bore 24 opening in an enlarged cylindrical recess 26. In said spaces, the upper body 14 receives an upper valve bore 24 opening in an enlarged cylindrical recess 26. In said spaces, the upper body 14 receives an upper valve bore 24 opening in an enlarged cylindrical recess 26. In said spaces, the upper body 14 receives an upper cylindrical space 22 from which downwardly extends an upper valve bore 24 opening in an enlarged cylindrical recess 26. In said spaces, the upper body 14 receives an upper cylindrical space 22 from which downwardly extends an upper valve bore 24 opening in an enlarged cylindrical recess 26. In said spaces, the upper body 14 receives an upper cylindrical space 22 from which downwardly extends an upper valve bore 24 opening in an enlarged cylindrical recess 26. In said spaces, the upper body 14 receives an upper cylindrical space 22 from which downwardly extends an upper valve bore 24 opening in an enlarged
  • electromagnetic actuator 28 that commands the displacements of an armature 30, arranged in the cylindrical space 22, having an integral valve stem 32 reciprocally sliding in the valve bore 24 along the main axis A and protruding in the recess 26.
  • the lower nozzle body 18 is provided with a main bore 34 axially extending from top to bottom.
  • injectors having the main bore 34 coaxial to the valve bore 24, as represented on the figures, or having an offset between the two axes.
  • the non-represented lowest part of the bore 34 narrows into a closed tip-end provided with a valve seat with injection holes, while the represented top part of the bore 34 enlarges into a cylindrical recess forming a control chamber 36.
  • a valve needle 38 is slidably guided in the bore 34 and is constantly downwardly solicited by a spring 39 compressed between a face of the nozzle body 18 and a spring seat 41 integral to the needle 38.
  • the spring 39 generates on the needle 38 a first downwardly oriented force FDl .
  • the upper part of the needle 38 forms a cylindrical piston 40 that protrudes in the control chamber 36 and, the lowest end of the needle 38 cooperates with the seat in order to enable or prohibit fuel injection through the injection holes.
  • the cylindrical piston 40 is provided with a diametral through-hole 42 and with an axial hole 44 upwardly extending inside the needle 38 from the hole 42 to the upper face 46 of the piston 40 where it opens.
  • the axial hole 44 comprises an intermediate orifice 48 having a restricted cross-section S48 relative to the section of the hole 44.
  • both ends of the diametral hole 42 open into the control chamber 36.
  • the diametral hole 42 with the axial hole 44 constitute an internal conduit creating fluid communication between the compression chamber 36 and the upper face 46 of the piston 40.
  • Alternative embodiments are possible such as a direct straight conduit arranged at an angle.
  • the valve plate 16 Arranged between the actuator body 14 and the nozzle body 18, the valve plate 16 has an upper face 50 in surface contact with the lower face 52 of the actuator body 14 and, a lower face 54 in surface contact with the upper face 56 of the nozzle body 18. Centrally, the lower face 54 of the plate 16 covers the control chamber 36 and constitutes a ceiling 58 to said control chamber 36.
  • the valve plate 16 is provided with a supply conduit 60 wherein part of the high pressure fuel can flow from the high pressure supply channel 20 to the control chamber 36 in passing through an inlet orifice 62 creating a restriction in the supply conduit 60.
  • the section S62 of the inlet orifice 62 is larger than the section S48 of the intermediate orifice 48.
  • the valve plate 16 is also provided with a return conduit 64 wherein low pressure fuel can flow from the cylindrical recess 26, provided in the upper body 14, toward a return outlet not represented.
  • the valve plate 16 is further provided with a central conduit 66 axially extending between its lower 54 and the upper 50 faces.
  • a central conduit 66 axially extending between its lower 54 and the upper 50 faces.
  • a shallow cylindrical recess 68 In the lower face 54 of the plate 16 is formed a shallow cylindrical recess 68 wherein centrally opens said central conduit 66.
  • the supply conduit 60 comprises an inwardly radially extending upper groove 70 provided in the upper face 50 of the valve plate 16 and, a complementary radially extending lower groove 72 provided in the lower face 54 of the valve plate 16.
  • the restricted inlet orifice 62 is axially arranged between the upper and lower grooves 70, 72.
  • the return channel 64 is another upper groove outwardly radially extending in the upper face 50.
  • valve stem 32 is in its utmost downward position where it closes the central conduit 66.
  • the needle 38 is in downward position cooperating with the valve seat, preventing injection events. This downward position is also known as a closed position.
  • valve stem 32 is moved upward opening the central conduit 66 into the cylindrical recess 26.
  • the valve needle 38 is in its utmost upper position, also known as a fully open position and, the upper face 46 of the piston 40 abuts against the ceiling 58 of the control chamber 36.
  • the diameter D68 of the shallow recess 68 is smaller than the diameter D40 of the piston 40 therefore, in this upper position, the piston 40 contacts the valve plate 16 along an annular surface 74 set at the peripheral edge of the shallow recess 68.
  • the control chamber 36 is limited to an annulus volume surrounding the piston 40.
  • the armature 30 and integral valve stem 32 are moved downward; the central conduit 66 is closed by the stem 32 and high pressure fuel pressurizes the volume consisting of the control chamber 36, the diametral through hole 42, the small axial hole 44, the central conduit 66 and, the shallow recess 68.
  • the high pressure built up the control chamber 36 generates on the upper face 46 of the piston 40 a second downwardly oriented force FD2 which adds to the first downward force FD1 and maintains the needle 38 in a downward position cooperating with the valve seat to close the injection holes and to prevent injection event.
  • the armature 30 and integral stem 32 are in upward position; the central conduit 66 is open in fluid communication with the return channel 64.
  • Pressurized fuel contained in the control chamber 36, the diametral through hole 42 and in the small axial hole 44 flows through the shallow recess 68 and the central conduit 66 to reach the cylindrical recess 26 and the return channel 64.
  • the needle 38 is no longer subject to the second force FD2 but, to an opposite upward force FU generated by the high pressure fuel acting on the lower extremity of the needle 38.
  • Said upward force FU is superior to the first downward force FDl of the spring 39 and consequently the needle 38 moves upward, enabling injection events.
  • the fuel present inside the shallow recess 68 gets trapped and slightly damps said final displacement.
  • the upper face 46 of the piston abuts against the ceiling 58 of the chamber 36 and therefore, a unique path of fuel remains open from the supply channel 20 to the return channel 64.
  • Said unique path consist of the upper groove 70, the inlet orifice 62, the lower groove 72, the annulus control chamber 36, the diametral through hole 42, the axial hole 44 and its intermediate restriction 48, the shallow recess 68, the central conduit 66, the cylindrical recess 26 and finally the return channel 64.
  • the pressure of the fuel decreases a first time when passing through the restriction of the inlet orifice 62, then decreases further when passing through the intermediate restriction 48. Therefore the fuel leak, occurring when the needle 38 is up, is minimized.
  • the intermediate restriction 48 having a cross section S48 smaller than the cross section S62 of the inlet orifice 62 generates a second pressure drop, the pressure being higher in the through hole 42 than above, in the central conduit 66 and the shallow recess 68. While the section S48 should be between 75% and 25% of the inlet orifice section S62, a preferred value is around 50%> where said section S48 is only about half the inlet orifice section S62.
  • the armature 30 and integral stem 32 are back in downward position again closing the central conduit 66, as in figure 1.
  • the needle 38 is still in its upward position.
  • the high pressure rapidly built-up again in the annulus control chamber 36, the diametral through hole 42, the small axial hole 44 and its intermediate restriction 48, the shallow recess 68 and the central conduit 66.
  • the high pressure in the shallow recess 68 re-generates on the upper face 46 of the piston the second downwardly oriented force FD2 which balances the upward force FU.
  • the hydraulic forces applied on the needle 38 are balanced and the first downward force FDl of the spring 39 becomes predominant downwardly displacing the needle 38.
  • injector 58 ceiling of the control chamber body 60 supply conduit
  • valve plate 64 return conduit

Landscapes

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

Abstract

La présente invention concerne un injecteur de carburant comportant un canal d'alimentation disposé dans son corps et comprenant une soupape de commande commandant hydrauliquement les déplacements d'un pointeau de soupape disposé à l'intérieur d'un alésage axial principal du corps. Le pointeau se déplace à va-et-vient entre une position fermée et une position complètement ouverte. L'alésage principal s'étend axialement d'une pointe pointue pourvue des trous d'injection à une extrémité supérieure formant une chambre de commande dans laquelle fait saillie l'extrémité supérieure du pointeau de soupape. La chambre de commande est en communication fluidique avec le canal d'alimentation haute pression par le biais d'un conduit d'alimentation et avec un canal de retour basse pression par le biais d'un autre conduit commandé par la soupape de commande, et le pointeau est pourvu d'un conduit interne s'étendant entre sa face supérieure et sa paroi latérale, où il débouche dans la chambre de commande.
PCT/EP2015/050841 2014-02-19 2015-01-19 Injecteur de carburant WO2015124340A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB201402921A GB201402921D0 (en) 2014-02-19 2014-02-19 Fuel injector
GB1402921.9 2014-02-19

Publications (1)

Publication Number Publication Date
WO2015124340A1 true WO2015124340A1 (fr) 2015-08-27

Family

ID=50440396

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2015/050841 WO2015124340A1 (fr) 2014-02-19 2015-01-19 Injecteur de carburant

Country Status (2)

Country Link
GB (1) GB201402921D0 (fr)
WO (1) WO2015124340A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115992785A (zh) * 2023-03-24 2023-04-21 哈尔滨工程大学 一种双针阀可变喷油速率的微量回油电控喷油器

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19826719A1 (de) * 1998-06-16 1999-12-23 Bosch Gmbh Robert Ventilsteuereinheit für ein Kraftstoffeinspritzventil
DE19936668A1 (de) * 1999-08-04 2001-02-22 Bosch Gmbh Robert Common-Rail-Injektor
DE10164394A1 (de) * 2001-12-28 2003-07-17 Bosch Gmbh Robert Kraftstoffeinspritzventil für eine Brennkraftmaschine
DE102012221470A1 (de) * 2012-11-23 2014-05-28 Robert Bosch Gmbh Brennstoffeinspritzventil

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19826719A1 (de) * 1998-06-16 1999-12-23 Bosch Gmbh Robert Ventilsteuereinheit für ein Kraftstoffeinspritzventil
DE19936668A1 (de) * 1999-08-04 2001-02-22 Bosch Gmbh Robert Common-Rail-Injektor
DE10164394A1 (de) * 2001-12-28 2003-07-17 Bosch Gmbh Robert Kraftstoffeinspritzventil für eine Brennkraftmaschine
DE102012221470A1 (de) * 2012-11-23 2014-05-28 Robert Bosch Gmbh Brennstoffeinspritzventil

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115992785A (zh) * 2023-03-24 2023-04-21 哈尔滨工程大学 一种双针阀可变喷油速率的微量回油电控喷油器

Also Published As

Publication number Publication date
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