(19)
(11)EP 3 365 549 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
11.12.2019 Bulletin 2019/50

(21)Application number: 16781472.2

(22)Date of filing:  14.10.2016
(51)International Patent Classification (IPC): 
F02M 53/04(2006.01)
F02M 61/14(2006.01)
(86)International application number:
PCT/EP2016/074738
(87)International publication number:
WO 2017/067855 (27.04.2017 Gazette  2017/17)

(54)

FUEL INJECTOR NOZZLE SHIELD

SCHILD FÜR EINE KRAFTSTOFFEINSPRITZDÜSE

ÉCRAN POUR BUSE D'INJECTEUR DE CARBURANT


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 20.10.2015 GB 201518531

(43)Date of publication of application:
29.08.2018 Bulletin 2018/35

(73)Proprietor: Delphi Technologies IP Limited
St. Michael (BB)

(72)Inventors:
  • KEELER, Nathan, Peter
    Hillingdon Middlesex UB10 9DX (GB)
  • PHILLIPS, Simon
    Cinderford Gloucestershire GL14 2LE (GB)

(74)Representative: Delphi France SAS 
c/o Delphi Technologies Campus Saint Christophe Bâtiment Galilée 2 10, avenue de l'Entreprise
95863 Cergy Pontoise Cedex
95863 Cergy Pontoise Cedex (FR)


(56)References cited: : 
DE-A1-102013 021 261
GB-A- 2 487 588
GB-A- 719 952
US-A1- 2015 040 857
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    TECHNICAL FIELD



    [0001] The present invention relates generally to a fuel injector and more particularly to shield to inserted between the nozzle of the injector and an engine block.

    BACKGROUND OF THE INVENTION



    [0002] Fuel injectors are typically inserted in deep well provided in engine block. More precisely, in each well is press-fitted an injector pocket member having a large section portion outwardly opening on the top face of the engine block and, a small section portion extending from the large portion and ultimately opening in a combustion chamber of the engine. In the injector pocket member is placed a fuel injector having a main large section body, that is arranged in the large section portion of the injector pocket and, a narrow section nozzle arranged in the small section portion of the injector pocket.

    [0003] More precisely, around the nozzle is press-fitted a tubular shield typically machined from copper alloy that has excellent thermal conductivity properties. The press-fit intimately links the shield to the nozzle and, around the shield is reserved an annular air gap of few tenths of millimeters between outer face of the shield and the inner face of the small section portion of the injector pocket member.

    [0004] Furthermore, at an extremity of the shield is provided a collar forming a disc outwardly extending from the tubular shield toward a peripheral circular edge. In use, the collar is compressed between a shoulder face of the injector pocket, which is between the large and the small portions, and a shoulder face of the injector nut of the fuel injector. Ultimately, the injector is maintained in place by a bracket member arranged over its top and that is screwed in the engine block downwardly biasing the injector and compressing the collar.

    [0005] In use, the shield enables in use to evacuate the heat generated in a combustion chamber and transferred to the nozzle, from said nozzle toward the engine block and, the collar seals the large section portion, in which is fuel at low pressure, from the small section portion.

    [0006] GB 719 952 A discloses a shield arranged between the nozzle of a fuel injector and an engine block, the shield having a thermal protecting member. Constant enhancement of performances requires improvement of the thermal protection of the nozzle.

    SUMMARY OF THE INVENTION



    [0007] It is an object of the invention to resolve or at least mitigate the above mentioned problem by providing shield adapted to be arranged between the nozzle of a fuel injector and an engine block. The shield has a metallic body comprising a tubular portion inside of which the cylindrical nozzle of the fuel injector can be press-fitted with interference and, that is able to be inserted with clearance in a cylindrical hole of the engine block.

    [0008] The shield further comprises a thermal protecting member arranged over the external face of the tubular portion.

    [0009] The thermal protecting member has a lower thermal conductivity than the metallic body.

    [0010] In an embodiment, the thermal protecting member is integral to the tubular portion, for instance, the thermal protecting member can be a coating of the external cylindrical face of the tubular member.

    [0011] In said embodiment, the coating can comprise tin.

    [0012] Also, the metallic body of the shield is made of copper alloy.

    [0013] The shield further comprises a collar forming a thick disc radially outwardly extending from an extremity of the tubular portion. The collar has a first face, or upper face, an opposed second face, or under face, and, a peripheral face joining the first face to the second face. In use, the collar is compressed between a shoulder face of the fuel injector abutting against the first face and, a shoulder face provided in the engine block abutting against the second face of the collar.

    [0014] The shield further comprises a fuel protecting member arranged over the peripheral face of the collar.

    [0015] The fuel protecting member further extends over the first face of the collar.

    [0016] The fuel protecting member is integral to the collar, for instance, the fuel protecting member can be a coating the collar. Said coating comprises tin.

    [0017] In an embodiment, the heat protecting coating and the fuel protecting coating are made of the same material.

    [0018] In another embodiment, the heat protecting member and the fuel protecting member are made of different materials.

    [0019] The invention further extends to a fuel injector having a cylindrical nozzle for delivering fuel in a combustion chamber of an internal combustion engine and, a shield press-fitted over said cylindrical nozzle, the shield being as described above.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0020] The present invention is now described by way of example with reference to the accompanying figure that is an axial section of the arrangement of the fuel injector in an engine block.

    DESCRIPTION OF THE PREFERRED EMBODIMENTS



    [0021] The arrangement of a fuel injector in an engine block is now described in reference to the figure. The description uses for simplification and clarity purposes the top-down arbitrary orientation of the figure without any intent to limit the scope of protection defined by the claims.

    [0022] An engine block 10 is provided with a coolant gallery 12, represented horizontal and, with a vertical opening 14 extending along a main axis Z and, in which is inserted with press-fit an injector pocket 16. The injector pocket 16 has a tubular body having a peripheral wall defining an internal volume V comprising a large section portion 18 upwardly opening in a top face of the engine block 10 and, a small section portion 20 downwardly opening in a combustion chamber 22 of the engine, said large and small section being joined via a transverse shoulder face 24.

    [0023] Inside said internal volume V is arranged a fuel injector 26 having a large section actuator member 28 from the bottom of which axially Z extends a narrow cylindrical nozzle assembly 30, said actuator member and nozzle fixed to each other by a cap nut 32 defining another transverse shoulder face 34.

    [0024] Press fitted onto the cylindrical nozzle 30 is a tubular shield 36, having a tubular portion 38 at an extremity of perpendicularly extends a collar 40. The tubular portion 38 is press fitted on the cylindrical nozzle 30 and it extends from an open lower extremity 42 up to an opposite open upper extremity 44 where outwardly perpendicularly the collar 40 is. As visible on the figure, the collar 40 has an upper face 46 radially extending from an internal circular edge that is common with the internal face 48 of the tubular portion to, an external circular edge that is common with a peripheral cylindrical face 50 of the collar. Similarly, parallel to the upper face 46, the collar 40 has an under face 52 radially extending toward an external circular edge that is common with the peripheral cylindrical face 50 of the collar. On the illustration the under face 52 merges with the cylindrical external face 54 of the tubular portion via a fillet, although this could be another shape such as a chamfer or a straight edge.

    [0025] Although several materials may be utilized for manufacturing the shield 36, it is known to use a copper alloy, such as Tellurium Copper (CuTeP), which has excellent thermal conductivity.

    [0026] The external face 54 of the tubular portion is covered by a thermal protecting coating 56 having a thermal conductivity inferior to the conductivity mentioned above for the core of the shield, one of the preferred materials for said thermal coating being a tin alloy.

    [0027] Also, the upper face 46 of the collar is covered by a fuel protecting coating 58 preventing direct fuel contacts between the copper alloy shied and fuel that may be present in the injector pocket 16. Although the materials of the thermal coating 56 and of the fuel protecting coating 58 may be chosen different from each other, having the same tin alloy for both coatings is preferred.

    [0028] Alternatively, the surface coatings that are integral to the shield, one may prefer to arrange independent metallic sleeves fixed over the tubular portion and over the upper and peripheral faces of the shield 36.

    [0029] Arranged for use as presented on the figure, the large actuator portion 28 occupies the large section of the injector pocket 16 and, the narrow nozzle 30 around which is press fitted the shield 36, is engaged with a clearance C of few tenths of millimeters in the small section portion 20 of the injector pocket. The collar 40 is axially Z compressed between the shoulder face 34 of the fuel injector and the shoulder face 24 of the injector pocket, the compression force being generated by a clamp, not shown, screwed on the top face of the engine block downwardly compressing the fuel injector inside the injector pocket. The thermal coating 56 limits the heat transfer from the vicinity of the combustion chamber 22 toward the nozzle 30 while the heat of the nozzle may be channeled by the tubular portion of the shield toward the collar then, through the contact between the under face of the collar to the injector pocket.

    LIST OF REFERENCES



    [0030] 
    Z
    main axis
    V
    internal volume of the injector pocket
    C
    clearance
    10
    engine block
    12
    coolant gallery
    14
    opening
    16
    injector pocket
    18
    large section portion of the injector pocket
    20
    small section portion of the injector pocket
    22
    combustion chamber
    24
    shoulder face of the injector pocket
    26
    fuel injector
    28
    actuator member
    30
    nozzle
    32
    capnut
    34
    shoulder face of the fuel injector
    36
    shield
    38
    tubular portion of the shield
    40
    collar
    42
    open lower extremity of the shield
    44
    open upper extremity of the shield
    46
    upper face of the collar - first face
    48
    internal face of the tubular wall
    50
    peripheral face of the collar
    52
    under face of the collar - second face
    54
    external face of the tubular portion
    56
    thermal protecting coating
    58
    fuel protecting coating



    Claims

    1. Shield (36) adapted to be arranged between the nozzle (30) of a fuel injector (26) and an engine block (10), the shield (36) having a metallic body comprising a tubular portion (38) inside of which the cylindrical nozzle of the fuel injector can be press-fitted with interference and, that is able to be inserted with clearance (C) in a cylindrical hole of the engine block and,
    the shield (56) further comprising a collar (40) forming a thick disc radially outwardly extending from an extremity of the tubular portion (38); the collar (40) having a first face (46), or upper face, an opposed second face (52), or under face, and, a peripheral face (50) joining the first face (46) to the second face (52);
    the collar (40) being, in use, compressed between a shoulder face (34) of the fuel injector abutting against the first face (46) and, a shoulder face (24) provided in the engine block abutting against the second face (52) of the collar,
    characterized in that
    the metallic body of the shield is made of copper alloy, the shield (36) further comprising a thermal protecting member (56) arranged over an external face (54) of the tubular portion and also a fuel protecting member (58) arranged over the peripheral face (50) of the collar and,

    wherein the fuel protecting member (58) further extends over the first face (46) of the collar and,

    wherein the fuel protecting member (58) is integral to the collar.


     
    2. Shield (36) as claimed in the preceding claim wherein the thermal protecting member (56) has a lower thermal conductivity than the metallic body.
     
    3. Shield (36) as claimed in any one of the preceding claims wherein the thermal protecting member (56) is integral to the tubular portion.
     
    4. Shield (36) as claimed in any one of the preceding claims wherein the thermal protecting member (56) is a coating of the external cylindrical face (54) of the tubular member.
     
    5. Shield (36) as claimed in claim 4 wherein said coating (56) comprises tin.
     
    6. Shield (36) as claimed in claim 1 wherein the fuel protecting member (58) is a coating of the collar.
     
    7. Shield (36) as claimed in claim 6 wherein said coating comprises tin.
     
    8. Shield (36) as claimed in claim 5 wherein the heat protecting coating (56) and the fuel protecting coating (58) are made of the same material.
     
    9. Shield (36) as claimed in the combination of claims 5 and 7 wherein the heat protecting member (56) and the fuel protecting member (58) are made of different materials.
     
    10. Fuel injector (26) having a cylindrical nozzle (30) for delivering fuel in a combustion chamber (22) of an internal combustion engine and, a shield (36) press-fitted over said cylindrical nozzle, the shield (36) being as claimed in any one of the preceding claims.
     


    Ansprüche

    1. Abschirmung (36), die ausgebildet ist, zwischen der Düse (30) eines Kraftstoffinjektors (26) und einem Motorblock (10) angeordnet zu sein, wobei die Abschirmung (36) einen metallischen Körper hat, der einen rohrförmigen Abschnitt (38) aufweist, in dessen Innerem die zylindrische Düse des Kraftstoffinjektors in Presspassung gebracht werden kann, und die mit Abstand (C) in ein zylindrisches Loch des Motorblocks eingesetzt werden kann, und
    die Abschirmung (56) weiter einen Kragen (40) aufweist, der eine dicke Scheibe bildet, die sich von einem Ende des rohrförmigen Abschnitts (38) radial nach außen erstreckt; wobei der Kragen (40) eine erste Fläche (46) oder obere Fläche, eine gegenüberliegende zweite Fläche (52) oder untere Fläche und eine Umfangsfläche (50) hat, die die erste Fläche (46) mit der zweiten Fläche (52) verbindet;
    wobei der Kragen (40), in Benutzung, zwischen einer an der ersten Fläche (46) anliegenden Schulterfläche (34) des Kraftstoffinjektors und einer an der zweiten Fläche (52) anliegenden Schulterfläche (24), die in dem Motorblock vorgesehen ist, zusammengedrückt wird,
    dadurch gekennzeichnet, dass
    der metallische Körper der Abschirmung aus einer Kupferlegierung besteht, wobei die Abschirmung (36) weiter ein Wärmeschutzelement (56) aufweist, das über einer Außenfläche (54) des rohrförmigen Abschnitts angeordnet ist, und auch ein Kraftstoffschutzelement (58), das über der Umfangsfläche (50) des Kragens angeordnet ist, und
    wobei sich das Kraftstoffschutzelement (58) weiter über die erste Fläche (46) des Kragens erstreckt, und
    wobei das Kraftstoffschutzelement (58) integral mit dem Kragen ist.
     
    2. Abschirmung (36) gemäß dem vorhergehenden Anspruch, wobei das Wärmeschutzelement (56) eine geringere Wärmeleitfähigkeit als der metallische Körper hat.
     
    3. Abschirmung (36) gemäß einem der vorhergehenden Ansprüche, wobei das Wärmeschutzelement (56) integral mit dem rohrförmigen Abschnitt ist.
     
    4. Abschirmung (36) gemäß einem der vorhergehenden Ansprüche, wobei das Wärmeschutzelement (56) eine Beschichtung der äußeren zylindrischen Fläche (54) des rohrförmigen Elements ist.
     
    5. Abschirmung (36) gemäß Anspruch 4, wobei die Beschichtung (56) Zinn aufweist.
     
    6. Abschirmung (36) gemäß Anspruch 1, wobei das Kraftstoffschutzelement (58) eine Beschichtung des Kragens ist.
     
    7. Abschirmung (36) gemäß Anspruch 6, wobei die Beschichtung Zinn aufweist.
     
    8. Abschirmung (36) gemäß Anspruch 5, wobei die Wärmeschutzbeschichtung (56) und die Kraftstoffschutzbeschichtung (58) aus dem gleichen Material bestehen.
     
    9. Abschirmung (36) gemäß der Kombination der Ansprüche 5 und 7, wobei das Wärmeschutzelement (56) und das Kraftstoffschutzelement (58) aus unterschiedlichen Materialien bestehen.
     
    10. Kraftstoffinjektor (26) mit einer zylindrischen Düse (30) zum Zuführen von Kraftstoff in eine Brennkammer (22) eines Verbrennungsmotors und einer über die zylindrische Düse pressgepassten Abschirmung (36), wobei die Abschirmung (36) gemäß einem der vorhergehenden Ansprüche ist.
     


    Revendications

    1. Écran (36) adapté pour être agencé entre la buse (30) d'un injecteur de carburant (26) et un bloc moteur (10), l'écran (36) ayant un corps métallique comprenant une portion tubulaire (38) à l'intérieur de laquelle la buse cylindrique de l'injecteur de carburant peut être engagée à la presse avec interférence et qui est capable d'être insérée avec jeu (C) dans un trou cylindrique du bloc moteur, et
    l'écran (56) comprenant en outre un collier (40) formant un disque épais radialement vers l'extérieur, s'étendant depuis une extrémité de la portion tubulaire (38) ; le collier (40) ayant une première face (46), ou face supérieure, une seconde face opposée (52), ou face inférieure, et une face périphérique (50) qui joint la première face (46) à la seconde face (52) ;
    le collier (40) étant, en utilisation, comprimé entre une face d'épaulement (34) de l'injecteur de carburant en butée contre la première face (46) et une face d'épaulement (24) ménagée dans le bloc moteur en butée contre la seconde face (52) du collier,
    caractérisé en ce que
    le corps métallique de l'écran est réalisé en alliage de cuivre, l'écran (36) comprenant en outre un élément de protection thermique (56) agencé par-dessus une face extérieure (54) de la portion tubulaire et également un élément protecteur de carburant (58) agencé par-dessus la face périphérique (50) du collier, et
    dans lequel l'élément protecteur de carburant (58) s'étend en outre par-dessus la première face (46) du collier, et
    dans lequel l'élément protecteur de carburant (58) est réalisé de manière intégrée au collier.
     
    2. Écran (36) selon la revendication précédente, dans lequel l'élément de protection thermique (57) a une conductivité thermique inférieure à celle du corps métallique.
     
    3. Écran (36) selon l'une quelconque des revendications précédentes, dans lequel l'élément de protection thermique (56) est réalisé de manière intégrée à la portion tubulaire.
     
    4. Écran (36) selon l'une quelconque des revendications précédentes, dans lequel l'élément de protection thermique (56) est un revêtement de la face cylindrique extérieure (54) de l'élément tubulaire.
     
    5. Écran (36) selon la revendication 4, dans lequel ledit revêtement (56) comprend de l'étain.
     
    6. Écran (36) selon la revendication 1, dans lequel l'élément de protection de carburant (58) est un revêtement du collier.
     
    7. Écran (36) selon la revendication 6, dans lequel ledit revêtement comprend de l'étain.
     
    8. Écran (36) selon la revendication 5, dans lequel le revêtement de protection thermique (56) et le revêtement de protection de carburant (58) sont réalisés du même matériau.
     
    9. Écran (36) selon la combinaison des revendications 5 et 7, dans lequel l'élément de protection thermique (56) et élément de protection de carburant (58) sont réalisés de matériaux différents.
     
    10. Injecteur de carburant (26) ayant une buse cylindrique (30) pour distribuer du carburant dans une chambre de combustion (22) d'un moteur à combustion interne, et un écran (36) engagé à la presse par-dessus ladite buse cylindrique, l'écran (36) étant tel que revendiqué dans l'une quelconque des revendications précédentes.
     




    Drawing








    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description