EP0537156B1 - Bougie d'allumage pour moteur a combustion interne - Google Patents

Bougie d'allumage pour moteur a combustion interne Download PDF

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Publication number
EP0537156B1
EP0537156B1 EP91907630A EP91907630A EP0537156B1 EP 0537156 B1 EP0537156 B1 EP 0537156B1 EP 91907630 A EP91907630 A EP 91907630A EP 91907630 A EP91907630 A EP 91907630A EP 0537156 B1 EP0537156 B1 EP 0537156B1
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EP
European Patent Office
Prior art keywords
electrode
cup
spark plug
billet
thermal conductivity
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Expired - Lifetime
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EP91907630A
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German (de)
English (en)
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EP0537156A1 (fr
EP0537156A4 (fr
Inventor
Michael Lenk
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Cooper Industries LLC
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Cooper Industries LLC
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Publication of EP0537156A4 publication Critical patent/EP0537156A4/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T13/00—Sparking plugs
    • H01T13/20—Sparking plugs characterised by features of the electrodes or insulation
    • H01T13/32—Sparking plugs characterised by features of the electrodes or insulation characterised by features of the earthed electrode
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T13/00—Sparking plugs
    • H01T13/20—Sparking plugs characterised by features of the electrodes or insulation
    • H01T13/39—Selection of materials for electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T21/00—Apparatus or processes specially adapted for the manufacture or maintenance of spark gaps or sparking plugs
    • H01T21/02—Apparatus or processes specially adapted for the manufacture or maintenance of spark gaps or sparking plugs of sparking plugs

Definitions

  • the present invention relates to a spark plug comprising an outer shell, a central electrode, an insulator surrounding the central electrode, said central electrode having a top end portion and a bottom end portion, and further comprising at least one ground electrode connected at at least one point to said outer shell and forming a spark gap with the bottom end portion of the central electrode.
  • At least one of the electrodes of the spark plug consists of an outer layer made of a corrosion resistant material and of an inner core made of a material having good thermal conductivity characteristics and a good corrosion and erosion resistance.
  • the invention further relates to several methods for forming the electrodes of said spark plug.
  • Spark plugs as defined above i. e. in particular spark plugs having at least one electrode made of two different materials (composite electodes), are well known in prior art.
  • the materials most commonly used in such electrodes are nickel or a nickel alloy for the outer layer, and copper or a copper alloy, respectively silver or a silver alloy for the inner core.
  • spark plug electrodes provided with an inner core of copper or of silver are to obtain a better performance of the plug, as compared to spark plug electrodes consisting of only one single material (such as for example nickel or a nickel alloy).
  • the better performance is due to the higher thermal conductivity characteristics of copper and of silver, i. e. the inner core made of copper or of silver evacuates more rapidly the heat produced by the combustion of the air/fuel mixture in the combustion chamber of the engine, so that the electrodes of the spark plug will remain cooler when the engine is running. This cooling action has a positive effect on the performance and on the useful life of the spark plug because it reduces the corrosion and the erosion of the electrodes.
  • silver has a verv good corrosion and erosion resistance, but its bad mechanical properties at high temperature (in particular as far as the ground electrode is concerned) and its relatively high price prevent the manufacture and use of spark plug electrodes completely made of pure silver, except possibly for very particular applications.
  • German patent application DE 24 044 54 shows a spark plug provided with a central electrode completely made of silver.
  • a spark plug provided with a central electrode made completely of pure silver cannot be manufactured with the best possible cost/benefit ratio.
  • German patent DE 26 14 274 discloses a spark plug wherein at least one of the two electrodes is made of an outer layer of a corrosion resistant material, such as for example a nickel alloy, and of an inner core made of silver.
  • the spark surface of each nickel/silver electrode i.e. the spark surfaces forming the spark gap between the central electrode and the ground electrode consist of an inner core made of silver and of an outer ring made of nickel or of a nickel alloy, i.e. of two materials having different resistances to corrosion and erosion.
  • This type of construction is in no way the best solution for guaranteeing the best performance and the longest possible useful life of composite electrodes. Indeed the silver core should ideally form alone the spark surface of a composite electrode of this type.
  • FR-A-2451648 describes a spark plug in which the central electrode comprises an outer layer of a material which has good thermal conductivity, for example copper or a copper alloy, and a central core of a material which is resistant to corrosion and erosion, e.g. nickel or a nickel alloy.
  • a first object of the present invention is to provide a novel spark plug having an improved performance and wherein the electrodes have a substantially prolonged useful life period.
  • a second object of the present invention is to provide a novel spark plug having the best possible cost/benefit ratio when compared with spark plugs provided with precious metal electrodes, or provided with copper cored nickel electrodes such as known in prior art.
  • a spark plug comprising an outer shell, a central electrode, an insulator surrounding the central electrode, and at least one ground electrode connected at at least one point to the outer shell, the central electrode having a spark surface at one end thereof which forms a spark gap with an opposed spark surface of the ground electrode, at least one of the electrodes comprising an outer layer of a first material and an inner core of one or more other materials, characterised in that the spark surface of said at least one electrode is provided by an exposed surface of said core which surface is substantially parallel to the longitudinal axis of said at least one electrode.
  • a spark plug according to the invention wherein the inner core of at least one of the electrodes consists of one single materials, can either have the feature that the lateral surface or surfaces of said projection are completely surrounded by the outer lever of said one electrode or that only a portion of the lateral surface or surfaces or only some of the later surfaces of said projection are surrounded by the outer layer of said one electrode.
  • Said one ground electrode has further the feature that the surface or surfaces of said projection, which are not surrounded bv the outer laver of said one electrode, are in alignment with the surface or surfaces of said electrode
  • a spark plug according to the invention wherein the inner core of at least one electrode consists of two materials, a first material nearest to the spark gap and a second material away from the spark gap, can either have the feature that the lateral surface or surfaces of said projection (first material) are completely surrounded by the outer layer of said one electrode or that only a portion of the lateral surface or surfaces or only some of the later surfaces of said projection (first material) are surrounded by the outer layer of said one electrode.
  • Said one ground electrode has further the feature that the surface or surfaces of said projection (first material), which are not surrounded by the outer layer of said one electrode, are in alignment with the surface or surfaces of said electrode.
  • Another object of the invention is to provide a novel spark plug comprising electrodes wherein not only the good thermal conductivity, but also the good corrosion and erosion resistance of silver is fully used without prohibitive costs.
  • the materials preferably used in the electrodes of the spark plug according to the invention are (a) for the outer layer : a corrosion resistant material such as for example nickel or a nickel alloy, (b) for the single material inner core : a material having good thermal conductivity characteristics and a good corrosion/erosion resistance such as for example silver or a silver alloy, and (c) for the two material inner core : a first material (nearest to the spark gap) having good thermal conductivity characteristics and a good corrosion/erosion resistance such as for example silver or a silver alloy and a second material (away from the spark gap) having good thermal conductivity characteristics such as for example copper or a copper alloy. It is to be noted that other materials could be used and in particular the silver could principally be replaced by other precious metals.
  • One method comprises the steps of :
  • the inner core consisting of the material having good thermal conductivity characteristics and a good corrosion/erosion resistance (i.e. the silver or the silver alloy) projects through the outer layer perpendicularly to the longitudinal axis of said one electrode and the lateral surface or surfaces of said projection are completely surrounded by the outer layer of said electrode.
  • Another method comprises the following steps :
  • the portion of the inner core consisting of the material having good thermal conductivity characteristics and a good corrosion/erosion resistance (i.e. the silver or the silver alloy) projects through the outer layer perpendicularly to the longitudinal axis of said one electrode and only a portion of the lateral surface or only some of the lateral surfaces of said projection are surrounded by the outer layer of said electrode
  • the composite electrode formed by the two above mentioned methods is a central electrode the extrusion butt at its top end can serve as a seat in the insulator of the spark plug. If said electrode is a ground electrode the extrusion butt is cut off and the electrode is then bent as required by the type of spark plug to be manufactured.
  • Figs 1 through 8 show eight different embodiments of a spark plug according to the invention. It is however to be noted that these embodiments are only examples because many other combinations are possible between (a) the ground electrodes according to the invention, (b) various prior art central electrodes, (c) the central electrodes according to the invention, (d) various prior art ground electrodes, and it is one of the major advantages of the invention to allow for a very large number of combinations, so that an adequate high performance spark plug can be provided for many different applications.
  • Figs 1, 2, 5 and 6 relate to spark plugs provided with different ground electrodes according to the invention and Figs 3, 4, 7 and 8 relate to spark plug provided with different central electrodes according to the invention.
  • Each of the spark plugs comprises an outer shell 1, a central electrode 2, 2A, 2B, 2C, 2D, an insulator 3 and a ground electrode 4, 4A, 4B, 4C, 4D. Between the central electrode and the ground electrode of each spark plug there is a spark gap 5, 5A which can be located either beneath or on the side of the lower portion of the corresponding central electrode.
  • the invention relates in particular to the structure of the ground and of the central electrodes such as respectively shown in Figs 1, 2, 5, 6 and Figs 3, 4, 7, 8.
  • Figs 9 through 12 Four possible structures of the ground electrode according to the invention are represented separately in Figs 9 through 12 and four possible structures of the central electrode according to the invention are represented separately in Figs 13 through 16.
  • Fig. 9 shows the first embodiment (see Fig. 1) of an electrode according to the invention, i. e. an elbow-shaped ground electrode 4A comprising an outer layer 6 and a single material inner core 7, said inner core 7 projecting (8) through the outer layer 6 perpendicularly to the longitudinal axis of the electrode near its bottom end surface 9.
  • the inner core 7 does not extend up to the two end surfaces 9,10 of the electrode.
  • Fig. 10 shows the second embodiment (see Fig. 2) of an electrode according to the invention, i. e. an elbow-shaped ground electrode 4B comprising an outer layer 16 and a single material inner core 17, said inner core 17 projecting (11) through the outer layer 16 perpendicularly to the longitudinal axis of the electrode at its bottom end surface 12.
  • the inner core 17 does not extend up to the top end surface 13 of the electrode, but it is in alignment with the bottom end surface 12 of the electrode.
  • the materials used in the ground electrodes of Figs 9 and 10 are : (a) a corrosion resistant material such as for example nickel or a nickel alloy for the outer layers 6, 16 and (b) a material having good thermal conductivity characteristics and a good corrosion and erosion resistance such as for example silver or a silver alloy for the inner cores 7,17.
  • Fig. 11 shows the fifth embodiment (see Fig. 5) of an electrode according to the invention, i. e. an elbow-shaped ground electrode 4C comprising an outer layer 26 and a two material inner core 27A (first material) 27 (second material), the portion 27A of the inner core projecting (14) through the outer layer 26 perpendicularly to the longitudinal axis of the electrode near its bottom end surface 15.
  • the inner core 27A, 27 does not extend up to the two end surfaces 15, 18 of the electrode.
  • Fig. 12 shows the sixth embodiment (see Fig. 6) of an electrode according to the invention , i. e. an elbow-shaped ground electrode 4D comprising an outer layer 36 and a two material inner core 37A (first material) 27 (second material), the portion 37A of the inner core projecting (19) through the outer layer 36 perpendicularly to the longitudinal axis of the electrode at its bottom end surface 20.
  • the portion 37 of the Inner core does not extend up to the top end surface 21 of the electrode, but the portion 37A of the inner core is in alignment with the bottom end surface 20 of the electrode
  • the materials used in the ground electrodes of Figs 11 and 12 are : (a) a corrosion resistant material such as for example nickel or a nickel alloy for the outer layers 26, 36, (b) a material having good thermal conductivity characteristics and a good corrosion and erosion resistance such as for example silver or a silver alloy for the first material (27A, 37A) of the inner cores and (c) a material having good thermal conductivity characteristics such as for example copper or a copper alloy for the second material ( 27, 37) of the inner cores.
  • a corrosion resistant material such as for example nickel or a nickel alloy for the outer layers 26, 36
  • a material having good thermal conductivity characteristics and a good corrosion and erosion resistance such as for example silver or a silver alloy for the first material (27A, 37A) of the inner cores
  • a material having good thermal conductivity characteristics such as for example copper or a copper alloy for the second material ( 27, 37) of the inner cores.
  • the central electrode 2A of Fig. 13, i. e. the third embodiment of an electrode according to the invention (see Fig. 3) has basically the same structure as the ground electrode 4A of Fig. 9. It comprises an outer layer 6A, a single material inner core 7A and a seat 10A (extrusion butt).
  • the inner core 7A projects (8A) through the outer layer 6A perpendicularly to the longitudinal axis of the electrode near its bottom end surface 9A.
  • the central electrode 28 of Fig. 14, 1. e. the fourth embodiment of an electrode according to the invention has basically the same structure as the ground electrode 48 of Fig. 10. It comprises an outer layer 16A, a single material inner core 17A end a seat 13A (extrusion butt). The inner core 17A projects (11A) through the outer layer 16A perpendicularly to the longitudinal axis of the electrode at its bottom end surface 12A.
  • the materials used in the central electrodes of Figs 13 and 14 are (a) a corrosion resistant material such as for example nickel or a nickel alloy for the outer layers 6A, 16A and (b) a material having good thermal conductivity characteristics and a good corrosion and erosion resistance such as for example silver or a silver alloy for the inner cores 7A, 17A.
  • the central electrode 2C of Fig. 15, i. e. the seventh embodiment of an electrode according to the invention (see Fig. 7) has basically the same structure as the ground electrode 4C of Fig. 11. It comprises an outer layer 26A, a two material inner core 27B, 27C and a seat 18A (extrusion butt). The portion 27C of the inner core projects (14A) through the outer layer 26A perpendicularly to the longitudinal axis of the electrode near its bottom end surface 15A.
  • the central electrode 2D of Fig. 16 i. e. the eighth embodiment of an electrode according to the invention (see Fig. 8) has basically the same structure as the ground electrode 4D of Fig. 12. It comprises an outer layer 36A, a two material inner core 37B, 37C and a seat 21A (extrusion butt).
  • the portion 37C of the inner core projects (19A) through the outer layer 36A perpendicularly to the longitudinal axis of the electrode at its bottom end surface 20A.
  • the materials used in the central electrodes of Figs 15 and 16 are : (a) a corrosion resistant material such as for example nickel or a nickel alloy for the outer layers 26A,36A, (b) a material having good thermal conductivity characteristics and a good corrosion and erosion resistance such as for example silver or a silver alloy for the first material (27C, 37C) of the Inner cores and (c) a material having good thermal conductivity characteristics such as for example copper or a copper alloy for the second material (27B, 37B) of the inner cores.
  • a corrosion resistant material such as for example nickel or a nickel alloy for the outer layers 26A,36A
  • a material having good thermal conductivity characteristics and a good corrosion and erosion resistance such as for example silver or a silver alloy for the first material (27C, 37C) of the Inner cores
  • a material having good thermal conductivity characteristics such as for example copper or a copper alloy for the second material (27B, 37B) of the inner cores.
  • spark plugs of a very large number of types can be manufactured by using each time one of the four ground electrodes 4A, 4B, 4C, 4D, (Figs 9 through 12) in combination with various prior art central electrodes or by using each time one of the four central electrodes 2A, 2B,2C,2D, (Figs 13 through 16) in combination with various prior art ground electrodes.
  • the central electrodes of Figs 1, 2, 5, 6 and the ground electrodes of Figs 3, 4, 7, 8 which are shown as single metal electrodes could be replaced by composite electrodes of a type or types different than the corresponding composite electrodes according to the invention.
  • Figs 17,18,19 and Figs 21,22 relate to the first method for making an electrode of a spark plug according to the invention.
  • Fig. 17 represents a tubular cup 22 having a closed end 24 (Fig. 18) and an open end 28. In its lateral wall it is provided with an opening 23 near its closed end 24.
  • the opening 23 can have various shapes such as for example : square, rectangular, circular, oval, etc. and it can have other dimensions than those shown.
  • Fig. 18 a cylindrical billet 25 has been inserted into the cup 22 and in Fig. 19 the open end portion 29 of the cup has been bent over the billet 25 inside the cup so as to form a composite billet 22A, 25.
  • Fig. 21 shows how the composite billet 22A,25 is inserted into an extrusion die 40 and
  • Fig. 22 shows how the electrode 2A is formed by extrusion.
  • This first method for making an electrode of a spark according to the invention comprises the steps of :
  • the corrosion resistant material used in this first method is preferably nickel or a nickel alloy and the material having good thermal conductivity characteristics and a good corrosion and erosion resistance is preferably silver or a silver alloy.
  • the electrode obtained by this first method is the central electrode 2A of Figs 3,13 which corresponds to the ground electrode 4A of Figs 1,9, the ground electrode 4A requiring the further steps of cutting off the extrusion butt 10A (Fig. 13) and of bending the body of the electrode.
  • Fig. 20 shows the composite billet 22A, 25B, 25A which is used in the second method for making an electrode according to the invention. It is substantially similar to the composite billet of Fig. 19, but comprises two cylindrical billets 258, 25A of different materials.
  • the second method for making an electrode of a spark plug according to the invention comprises the steps of :
  • the corrosion resistant material used in this second method is preferably nickel or a nickel alloy, the material having good thermal conductivity characteristics and a good corrosion and erosion resistance is preferably silver or a silver alloy, and the material having good thermal conductivity characteristics is preferably copper or a copper alloy.
  • the electrode obtained by this second method is the central electrode 2C of Figs 7, 15 which corresponds to the ground electrode 4C of Figs 5, 11, the ground electrode 4C requiring the further steps of cutting off the extrusion butt 18A (Fig. 15) and of bending the body of the electrode
  • the opening 23 in the lateral wall of the tubular cup 22 used in the first and in the second method for making a spark plug according to the invention can, as already said above, have various shapes and dimensions. Consequently the projections 8, 14, 8A, 14A of the finished electrode 4A, 4C, 2A, 2C can also have various shapes and dimensions. In particular the dimensions of said projections 8, 14, 8A, 14A can be such that directly in front of the bottom end surface (spark surface) of the other electrode 2,4 of the spark plug only the outside surface of the inner core 7, 27A, 7A, 27C of said finished electrode 4A, 4C, 2A, 2C is visible.
  • no portion of the outer layer 6, 26, 6A, 26A of said finished electrode 4A, 4C, 2A, 2C is located directly in front of the bottom end surface of the other electrode 2, 4 of the spark plug.
  • the metal silver or a silver alloy having the best corrosion and erosion resistance is located directly in front of the bottom end surface of the other electrode 2, 4.
  • Figs 23, 24 and Figs 26, 27 relate to the third method for making an electrode of a spark plug according to the invention.
  • Fig 23 represents a tubular cup having a closed end 34 (Fig. 24) and an open end 38. In its lateral wall a recess 33 has been formed at Its open end 38. The recess 33 can have configurations and dimensions different from those shown.
  • Fig. 24 a cylindrical billet 35 has been inserted into the cup so as to form a composite billet 32, 35.
  • Fig 26 shows how the composite billet 32, 35 is inserted into an extrusion die 40 and
  • Fig. 27 shows how the electrode 28 is formed by extrusion.
  • the third method for making an electrode of a spark plug according to the invention comprises the steps of :
  • the corrosion resistant material used in this third method is preferably nickel or a nickel alloy and the material having good thermal conductivity characteristics and a good corrosion and erosion resistance is preferably silver or a silver alloy.
  • the electrode obtained by this first method is the central electrode 2B of Figs 4,14 which corresponds to the ground electrode 4B of Figs 2,10, the ground electrode 4B requiring the further steps of cutting off the extrusion butt 13A (Fig. 14) and of bending the body of the electrode.
  • Fig. 25 shows the composite billet 32, 35B, 35A which is used in the fourth method for making an electrode according to the invention. It is substantially similar to the composite billet of Fig. 24, but comprises two cylindrical billets 35B, 35A of different materials.
  • the fourth method for making an electrode of a spark plug according to the invention comprises the steps of :
  • the corrosion resistant material used in this fourth method is preferably nickel or a nickel alloy, the material having good thermal conductivity characteristics and a good corrosion and erosion resistance is preferably silver or a silver alloy, and the material having good thermal conductivity characteristics is preferably copper or a copper alloy.
  • the electrode obtained by this fourth method is the central electrode 2D of Figs 8,16 which corresponds to the ground electrode 4D of Figs 6, 12, the ground electrode 4D requiring the further steps of cutting off the extrusion butt 21A (Fig. 16) and of bending the body of the electrode.
  • the recess 33 in the lateral wall of the tubular cup 32 used in the third and in the fourth method for making a spark plug according to the invention can have various shapes and dimensions. Consequently the projections 11, 19, 11A, 19A of the finished electrode 4B, 4D,2B,2D can also have various shapes and dimensions. In particular the dimensions of said projections 11,19,11A,19A can be such that directly in front of the bottom end surface (spark surface) of the other electrode 2, 4 of the spark plug only the outside surface of the inner core 17,37A,17A,37C, of said finished electrode 4B,4D,2B,2D is visible.
  • no portion of the outer layer 16, 36,16A,36A of said finished electrode 4B, 4D, 2B, 2D is located directly in front of the bottom end surface of the other electrode 2, 4 of the spark plug.
  • the metal silver or a silver alloy having the best corrosion and erosion resistance is located directly in front of the bottom end surface of the other electrode 2, 4.
  • the reduced diameter extrusion orifice 40B of the extrusion die 40 can principally have a cross section of any shape, such as for example : circular, oval, square rectangular, etc. Electrodes having various cross sections can thus be made by the four above described methods.

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Claims (16)

  1. Bougie d'allumage comprenant une coque extérieure (1), une électrode centrale (2,2A,2B,2C,2D), un isolant (3) entourant l'électrode centrale, et au moins une électrode de masse (4,4A,4B,4C,4D) raccordée, en au moins un point, à la coque extérieure (1), l'électrode centrale (2,2A,2B,2C,2D) possédant, à une première extrémité, une surface de formation d'étincelles, qui forme un intervalle de production d'étincelles avec une surface opposée de formation d'étincelles de l'électrode de masse (4,4A,4B,4C, 4D), au moins l'une des électrodes comprenant une couche extérieure (6,16,26,36,6A,16A,26A,36A) formée d'un premier matériau et un noyau intérieur (7,17,27A,37,37A,7A,17A,27B, 27C,37B,37C) formé par un ou plusieurs autres matériaux, caractérisée en ce que la surface de formation d'étincelles de ladite au moins une électrode est formée par une surface à nu dudit noyau, laquelle surface est essentiellement parallèle à l'axe longitudinal de ladite au moins une électrode.
  2. Bougie d'allumage selon la revendication 1, dans laquelle le noyau intérieur de ladite au moins une électrode fait saillie à travers la couche extérieure, perpendiculairement à l'axe longitudinal de ladite électrode.
  3. Bougie d'allumage selon la revendication 2, dans laquelle la ou les surfaces latérales de ladite partie saillante (8,14,8A,14A) sont entièrement entourées par la couche extérieure (6,26,6A,26A) de ladite électrode (4A,4C,2A,2C).
  4. Bougie d'allumage selon la revendication 2, dans laquelle seule une partie de la surface latérale ou seule certaines des surfaces latérales de ladite partie saillante (11,19,11A,19A) sont entourées par la couche extérieure (16,36,16A,36A) de ladite électrode (4B,4D,2B, 2D).
  5. Bougie d'allumage selon la revendication 4, dans laquelle la ou les surfaces de ladite partie saillante (8,11,14,19,8A,11A,14A,19A), qui ne sont pas entourées par la couche extérieure (6,16,26,26,6A,16A,26A,36A) de ladite électrode (4A,4B,4C,4D,2A,2B,2C,2D), sont alignées avec la ou les surfaces de ladite électrode (4A,4B,4C,2A,2B,2C,2D).
  6. Bougie d'allumage selon l'une quelconque des revendications précédentes, dans laquelle le noyau intérieur (7,17,7A,17A) d'au moins l'une des électrodes (4A,4B,2A,2B) est constitué en un seul matériau, caractérisé en ce que le matériau de la couche extérieure (6,16,6A,16A) est un matériau résistant à la corrosion et le matériau unique du noyau intérieur (16,17,16A,17A) est un matériau possédant de bonnes caractéristiques de conductivité thermique et une bonne résistance à la corrosion et à l'érosion.
  7. Bougie d'allumage selon la revendication 6, dans laquelle le matériau de la couche extérieure (6,16, 6A,16A) est du nickel ou un alliage de nickel, et le matériau unique du noyau intérieur (7,17,7A,17A) est de l'argent ou un alliage d'argent.
  8. Bougie d'allumage selon l'une quelconque des revendications 1 à 5, dans laquelle le noyau intérieur (27,27A,37,37A,27B,27C,37B,37C) d'au moins l'une des électrodes (4C,4D,2C,2D) est formé de deux matériaux, un premier matériau disposé le plus près de l'intervalle de formation d'étincelles (5,5A) et un second matériau éloigné de l'intervalle de formation d'étincelles (5,5A), caractérisée en ce que le matériau de la couche extérieure (26,36, 26A,36A) est un matériau résistant à la corrosion, le premier matériau du noyau intérieur (27A,37A,27C,37C) est un matériau possédant de bonnes caractéristiques de conductivité thermique et une bonne résistance à la corrosion et à l'érosion, et le second matériau du noyau intérieur (27,37,27B,37B) est un matériau possédant de bonnes caractéristiques de conductivité thermique.
  9. Bougie d'allumage selon la revendication 8, dans laquelle le matériau de la couche extérieure (26,36, 26A,36A) est du nickel ou un alliage de nickel, le premier matériau du noyau intérieur (27A,37A,27C,37C) est de l'argent ou un alliage d'argent et le second matériau du noyau intérieur (27,37,27B,37B) est du cuivre ou un alliage de cuivre.
  10. Procédé pour fabriquer une électrode (2A) d'une bougie d'allumage selon la revendication 6, comprenant les étapes consistant à :
    a) former un pot tubulaire (22) possédant une extrémité fermée et une extrémité ouverte (24,28) et réalisé en un matériau résistant à la corrosion, ledit pot (22) possédant une ouverture (23) aménagée dans sa paroi latérale à proximité de son extrémité fermée (24);
    b) positionner une billette (25) possédant une forme cylindrique et réalisée en un matériau possédant de bonnes caractéristiques de conductibilité thermique et une bonne résistance à la corrosion et à l'érosion, à l'intérieur du pot (22) de manière qu'elle vienne en contact avec la surface d'extrémité intérieure fermée (24) du pot (22) et qu'elle vienne ainsi en contact avec la surface latérale intérieure du pot (22), hormis au niveau d'une partie située à son extrémité ouverte (28) et replier (29) ladite partie d'extrémité ouverte du pot (22) par-dessus la billette (25) à l'intérieur du pot (22); et
    c) insérer la billette composite résultante (22A, 25), son extrémité fermée (24) en premier, dans un perçage de montage avec ajustement serré (40A) d'une filière d'extrusion (40) possédant un orifice d'extrusion (40B) de diamètre réduit et faire avancer un piston (41) dans ledit perçage (40A) de manière à repousser à force la majeure partie de la billette composite (22A,25) à travers l'orifice d'extrusion (40B), en laissant dépasser de l'orifice d'extrusion (40B) uniquement un culot d'extrusion (10A) à l'extrémité supérieure de l'électrode composite (2A) ainsi formée.
  11. Procédé pour fabriquer une électrode (2C) d'une bougie d'allumage selon la revendication 8 et comprenant les étapes consistant à :
    (a) former un pot tubulaire (22) possédant une extrémité fermée et une extrémité ouverte (24,28) réalisée en un matériau résistant à la corrosion, ledit pot (22) possédant une ouverture (23) aménagée dans sa paroi latérale à proximité de son extrémité fermée (24);
    b) positionner une première billette (25B) possédant une forme cylindrique et réalisée en un matériau possédant de bonnes caractéristiques de conductibilité thermique et une bonne résistance à la corrosion et à l'érosion, à l'intérieur du pot (22) de manière qu'elle vienne en contact avec la surface d'extrémité intérieure fermée (24) du pot (22) et qu'elle vienne ainsi en contact avec la surface latérale intérieure du pot (22), jusque sur une certaine distance au-delà de ladite ouverture (23);
    c) positionner une seconde billette composite résultante (25A) possédant une forme cylindrique et réalisée en un matériau présentant de bonnes caractéristiques de conductibilité thermique, à l'intérieur du pot (22) de manière qu'elle vienne en contact avec la surface supérieure de la première billette (25B) et qu'elle vienne en contact avec la surface latérale intérieure du pot (22) hormis en ce qui concerne une partie située à son extrémité supérieure (28), et replier (29) ladite partie d'extrémité ouverte du pot (22) par-dessus les billettes (25B,25A) à l'intérieur du pot (22); et
    d) insérer la billette composite résultante (22A, 25), son extrémité fermée (24) en premier, dans un perçage de montage avec ajustement serré (40A) d'une filière d'extrusion (40) possédant un orifice d'extrusion (40B) de diamètre réduit et faire avancer un piston (41) dans ledit perçage (40A) de manière à repousser à force la majeure partie de la billette composite (22A,25B,25A) à travers l'orifice d'extrusion (40B), en laissant dépasser de l'orifice d'extrusion (40B) uniquement un culot d'extrusion (18A) à l'extrémité supérieure de l'électrode composite (2C) ainsi formée.
  12. Procédé pour fabriquer une électrode (2B) d'une bougie d'allumage selon la revendication 6 et comprenant les étapes consistant à :
    a) former un pot tubulaire (32) possédant une extrémité fermée et une extrémité ouverte (34,38) en un matériau résistant à la corrosion de telle sorte que sur une partie circonférentielle du pot (32), la longueur (A,B) du pot (32) diffère de ce qu'elle est pour l'autre partie circonférentielle du pot;
    b) positionner une billette (35) possédant une forme cylindrique et réalisée en un matériau ayant de bonnes caractéristiques de conductibilité thermique et une bonne résistance à la corrosion et à l'érosion, avec le pot (32) de manière qu'elle vienne en contact avec la surface de l'extrémité intérieure fermée (34) et avec la surface intérieure latérale du pot (32); et
    c) introduire la billette composite résultante (32,35), son extrémité fermée (38) en premier, dans un perçage de montage avec ajustement serré (40A) d'une filière d'extrusion (40) possédant un orifice d'extrusion (40B) de diamètre réduit et faire avancer un piston (41) dans ledit perçage (40A) de manière à repousser à force la majeure partie de la billette composite (32,35) à travers l'orifice d'extrusion (40B), en laissant dépasser de l'orifice d'extrusion (40B) uniquement un culot d'extrusion (13A) à l'extrémité supérieure de l'électrode composite (2B) ainsi formée.
  13. Procédé pour fabriquer une électrode (2D) d'une bougie d'allumage selon la revendication 8 et comprenant les étapes consistant à :
    a) former un pot tubulaire (32) possédant une extrémité fermée et une extrémité ouverte (34,38) en un matériau résistant à la corrosion de telle sorte que sur une partie circonférentielle du pot (32), la longueur (A,B) du pot (32) diffère de ce qu'elle est pour l'autre partie circonférentielle du pot;
    b) positionner une première billette (35B) possédant une forme cylindrique et réalisée en un matériau possédant une bonne caractéristique de conductibilité thermique dans le pot (32) de manière qu'elle vienne en contact avec la surface de l'extrémité intérieure fermée (34) et une partie de la surface latérale intérieure du pot (32); et
    c) positionner une seconde billette (35A) possédant une forme cylindrique et réalisée en un matériau possédant une bonne caractéristique de conductibilité thermique et une bonne résistance à la corrosion et à l'érosion à l'intérieur du pot (32); et
    d) insérer la billette composite résultante (32,25B,35A), son extrémité fermée (38) en premier, dans un perçage de montage avec ajustement serré (40A) d'une filière d'extrusion (40) possédant un orifice d'extrusion (40B) de diamètre réduit et faire avancer un piston (41) dans ledit perçage (40A) de manière à repousser à force la majeure partie de la billette composite à travers l'orifice d'extrusion (40B), en laissant dépasser de l'orifice d'extrusion (40B) uniquement un culot d'extrusion (21A) à l'extrémité supérieure de l'électrode composite (2D) ainsi formée.
  14. Procédé selon la revendication 10 ou 12, selon lequel le matériau résistant à la corrosion est du nickel ou un alliage de nickel et le matériau possédant une bonne caractéristique de conductibilité thermique et une bonne résistance à la corrosion et à l'érosion est de l'argent ou un alliage d'argent.
  15. Procédé selon la revendication 11 ou 13, selon lequel le matériau résistant à la corrosion est du nickel ou un alliage de nickel, le matériau possédant une bonne caractéristique de conductibilité thermique est du cuivre ou un alliage de cuivre, et le matériau possédant une bonne caractéristique de conductibilité thermique et une bonne résistance à la corrosion et à l'érosion est de l'argent ou un alliage d'argent.
  16. Procédé pour fabriquer une électrode de masse (4A,4B,4C,4D) selon la revendication 14 ou 15 et comprenant les étapes consistant à découper le culot d'extrusion (10A, 13A,18A,21A) au niveau de l'extrémité supérieure de l'écrou (2A,2B,2C,2D) et à donner une forme coudée à ladite électrode (4A,4B,4C,4D).
EP91907630A 1990-04-04 1991-04-02 Bougie d'allumage pour moteur a combustion interne Expired - Lifetime EP0537156B1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB9007659A GB2242703B (en) 1990-04-04 1990-04-04 Spark plug for internal combusiton engine
GB9007659 1990-04-04
PCT/US1991/002239 WO1991015887A1 (fr) 1990-04-04 1991-04-02 Bougie d'allumage pour moteur a combustion interne

Publications (3)

Publication Number Publication Date
EP0537156A1 EP0537156A1 (fr) 1993-04-21
EP0537156A4 EP0537156A4 (fr) 1994-04-27
EP0537156B1 true EP0537156B1 (fr) 1996-07-03

Family

ID=10673905

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91907630A Expired - Lifetime EP0537156B1 (fr) 1990-04-04 1991-04-02 Bougie d'allumage pour moteur a combustion interne

Country Status (6)

Country Link
EP (1) EP0537156B1 (fr)
AT (1) ATE140107T1 (fr)
AU (1) AU7682291A (fr)
DE (1) DE69120677T2 (fr)
GB (1) GB2242703B (fr)
WO (1) WO1991015887A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2242703B (en) * 1990-04-04 1994-02-16 Champion Spark Plug Europ Spark plug for internal combusiton engine
GB2276207B (en) * 1993-03-18 1996-09-04 Nippon Denso Co A spark plug and a method of producing the same
DE69323192T2 (de) * 1993-08-02 1999-06-17 Cooper Automotive Products, Inc. (N.D.Ges.D. Staates Delaware), Houston, Tex. Zündkerzenelektroden

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3146370A (en) * 1962-06-21 1964-08-25 Gen Motors Corp Spark plug with improved electrode
US3356882A (en) * 1965-10-21 1967-12-05 Ford Motor Co Spark plug having the center electrode sheath with a nickel alloy
US3967149A (en) * 1973-07-05 1976-06-29 Champion Spark Plug Company Spark plug
US4351095A (en) * 1977-12-12 1982-09-28 United Kingdom Atomic Energy Authority Method of making spark plugs
CA1138626A (fr) * 1978-12-16 1983-01-04 Gkn Floform Limited Fabrication d'electrodes bimetalliques pour bougies d'allumage
GB2047339A (en) * 1979-03-13 1980-11-26 Texas Instruments Inc Spark plugs and center electrodes therefor
DE3009721A1 (de) * 1979-03-13 1980-09-25 Texas Instruments Inc Zuendkerze und zuendkerzen-mittelelektrode
GB2068453B (en) * 1979-12-07 1983-12-14 Texas Instruments Inc Spark plugs and center electrodes therefor
US4526551A (en) * 1980-05-30 1985-07-02 Champion Spark Plug Company Production of electrodes
US4695759A (en) * 1981-10-29 1987-09-22 Champion Spark Plug Company Method for producing a composite center electrode and an electrode
US4585421A (en) * 1983-11-23 1986-04-29 The National Machinery Company Method of making copper-clad bimetal electrodes for spark plugs
GB2242703B (en) * 1990-04-04 1994-02-16 Champion Spark Plug Europ Spark plug for internal combusiton engine

Also Published As

Publication number Publication date
GB2242703A (en) 1991-10-09
EP0537156A1 (fr) 1993-04-21
EP0537156A4 (fr) 1994-04-27
ATE140107T1 (de) 1996-07-15
DE69120677T2 (de) 1996-12-12
AU7682291A (en) 1991-10-30
GB2242703B (en) 1994-02-16
GB9007659D0 (en) 1990-05-30
WO1991015887A1 (fr) 1991-10-17
DE69120677D1 (de) 1996-08-08

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