EP1662626B1 - New mounting method of a spark plug and bobbin assembly using a transmission of the tightning couple through the bobbin housing - Google Patents

New mounting method of a spark plug and bobbin assembly using a transmission of the tightning couple through the bobbin housing Download PDF

Info

Publication number
EP1662626B1
EP1662626B1 EP05300966A EP05300966A EP1662626B1 EP 1662626 B1 EP1662626 B1 EP 1662626B1 EP 05300966 A EP05300966 A EP 05300966A EP 05300966 A EP05300966 A EP 05300966A EP 1662626 B1 EP1662626 B1 EP 1662626B1
Authority
EP
European Patent Office
Prior art keywords
spark plug
casing
shell
essentially
inductive
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.)
Not-in-force
Application number
EP05300966A
Other languages
German (de)
French (fr)
Other versions
EP1662626A1 (en
Inventor
Xavier Jaffrezic
André AGNERAY
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.)
Renault SAS
Original Assignee
Renault SAS
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 Renault SAS filed Critical Renault SAS
Publication of EP1662626A1 publication Critical patent/EP1662626A1/en
Application granted granted Critical
Publication of EP1662626B1 publication Critical patent/EP1662626B1/en
Not-in-force legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • H01T13/02—Details
    • H01T13/08—Mounting, fixing or sealing of sparking plugs, e.g. in combustion chamber
    • 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
    • H01T13/40—Sparking plugs structurally combined with other devices
    • H01T13/44—Sparking plugs structurally combined with other devices with transformers, e.g. for high-frequency ignition

Definitions

  • the tightening torque of the spark plug is generally applied to the base of said spark plug, said cap comprising, conventionally, a male thread intended to cooperate with a thread. complementary female made in the cylinder head, and an element for the controlled tightening of said threaded assembly.
  • a mounting method then requires the use of a specific tool that is slid around said coil and said spark plug, in said access well to said spark plug: such a configuration therefore imposes, in particular, that there is, around said coil and in said access shaft to said candle, an unused free space outside the assembly operations and disassembly of the candle.
  • the existence of such a space goes against the dimensional constraints previously mentioned.
  • conductive thin layer of a material having a high electrical conductivity will also denote a metal layer of non-magnetic material having a thickness at least equal to or greater than the skin thickness in the frequency domain under consideration. that is, between 1 Megahertz and 10 Megahertz, ensuring an electromagnetic shielding function.
  • the high electrical conductivity of the materials will be similar to that of copper or silver, reference materials in this field (the value of the electrical conductivity of copper is 5.9 x 10 7 Siemens per meter and that of silver is greater than that of copper).
  • a cap consisting of a substantially cylindrical tubular portion terminated by a substantially planar flange whose outer diameter is greater than the diameter of said access well and whose surface is substantially perpendicular to the axis of said tubular portion and said well; access, is then placed on the upper part of the candle.
  • the dimensions of said cap are adjusted so that, when said substantially flat flange bears against the upper face of said candle access well, the end of the tubular portion of said cap bears against a portion of said spark plug, thus ensuring a compression hold of said spark plug in its access well: the tightening of the assembly is achieved by screwing said substantially flat flange on said upper face of said combustion chamber.
  • the coil is further integrated in said cap, the electrical contact between said coil and said spark plug being made by means of a helical spring placed in compression during the positioning of said cap.
  • Such a device if it eliminates the need to provide a space specifically for the passage of a clamping tool in the access well to the candle, however requires the achievement of a large number of parts precision.
  • publication EP0969575 proposes a candle associated with a coil.
  • the candle in this publication is a classic spark plug model and does not have any capacitive parts, such as radiofrequency plasma candles.
  • a radiofrequency plasma spark plug generally comprises an upper part, essentially inductive, consisting mainly of the coil of said spark plug and a shielding jacket of said essentially inductive portion, and a substantially capacitive lower portion composed mainly of a structure coaxial, the whole behaving like an LC resonator.
  • a substantially capacitive lower portion composed mainly of a structure coaxial, the whole behaving like an LC resonator.
  • the dimensions of said elements of said resonator must be defined, as a function of the radiofrequency operating domain, so as to optimizing the performance of said resonator: in particular, the length of said substantially capacitive portion should be as small as possible, so that the value of the capacitance remains low; in addition, the diameter of said substantially inductive portion should be as high as possible, so that the value of the overvoltage coefficient of the resonator thus formed is optimal.
  • the document DE-C-19 723 784 discloses a spark plug according to the preamble of claim 1.
  • the object of the present invention is to propose an assembly device in which the connection between the coil and the other elements constituting the spark plug ensures both electrical continuity and mechanical coupling, while allowing the assembly to be put in place. thus constituted without having to slide a tool around said coil to come to bear on the base of said candle.
  • the invention applies to a radiofrequency plasma spark plug.
  • the invention achieves its goal by means of a spark plug according to claim 1.
  • said essentially capacitive portion of said spark plug comprises, in particular, a base surrounding a substantially cylindrical central electrode and acting as a high voltage electrode, and said essentially inductive part of said spark plug is made in one or several materials and has a configuration for transmitting a torque to said base of said candle.
  • said base has, on the outer face of its part closest to the cylinder head of said internal combustion engine equipped with said spark plug, a suitable shape for the introduction and tightening of said spark plug on said cylinder head; said spark plug further comprising, at its end opposite its nearest end of said yoke, a connection element integral with a connecting device, said connecting element having a suitable shape enabling, by virtue of said transmission of said substantially inductive portion to said base, a tightening torque, the use of a simple and compact tool for the introduction and tightening of said spark plug on said cylinder head of said engine.
  • a radiofrequency plasma plug 1 of substantially cylindrical general shape mainly comprises a substantially capacitive lower part C and an essentially inductive upper part I, said parts C and I being of shape. substantially elongated, connected in series and having a common longitudinal axis Z.
  • Said substantially capacitive portion C comprises, in particular, a base 2 intended to be connected to the ground and surrounding a central electrode 3, substantially cylindrical, axis Z, acting as a high voltage electrode.
  • An insulator 4 is placed between the base 2 and the central electrode 3, said insulator 4 being configured to guide the sparks between the electrodes 2 and 3.
  • said base 2 has, on the outer face of its lower part closest to the cylinder head of the internal combustion engine equipped with said spark plug 1, a shape suitable for placing, holding and tightening said spark plug 1 on said cylinder head (for example and without limitation, as shown in Figure 1: a thread).
  • Said essentially inductive part I of said spark plug 1 comprises, for its part, a winding 5 whose axis is advantageously substantially coincident with the axis Z of the central electrode 3 and the spark plug 1.
  • Said winding 5 is, moreover surrounded by an envelope 6, preferably made of a nonmagnetic conductive material, intended to reduce the electromagnetic emissions of said spark plug 1 and to act as a shield, the dimensions of said envelope 6 being calculated so as to minimize the risks of breakdown between said winding 5 and said envelope 6.
  • an insulator 7 is placed between said winding 5 and said envelope 6, and said winding 5 is made around a solid element 8 made of a non-magnetic insulating material.
  • a complementary insulator 9 is furthermore placed between said insulator 7 and said insulator 4 separating said base 2 and said central electrode 3, a part 10 electrically connected to said base 2 ensuring the connection between the holding of said insulators 4, 7, and 9.
  • a current measuring winding 11 is also generally made around said winding 5, and a connection device 13, integral with a connector 12 (not detailed in the figures), is placed at the upper end of said candle 1.
  • a end of said coil 5 is connected to said connector 12, the other end of said coil 5 being connected by appropriate means 14 (not detailed in the figures) to an inner end of said central electrode 3.
  • such a candle 1 behaves like an LC resonator, in which the capacitive part and the inductive part are placed in series, and in which the capacitive part C is composed by the base 2, the central electrode 3, the insulator 4 placed between said central electrode 3 and said base 2, and by the internal parasitic capacitances related to the geometry of said spark plug 1, the essentially inductive part I consisting mainly of the winding 5, the insulator 7 and the envelope 6.
  • the length of the connection between said substantially capacitive portion C and said substantially inductive portion I should be reduced as much as possible.
  • the overvoltage coefficient of the resonator LC constituted by said substantially inductive portion I and said substantially capacitive portion C placed in series is even better than the diameter of said substantially inductive portion I is high.
  • the electrical quality of said connection between said substantially capacitive C and inductive I portions (continuity electrical, in particular) must also be maximum in order to optimize the performance of said resonator.
  • the device according to the invention proposes to introduce a rigid connection mode between some of the elements of each of the essentially capacitive parts C and essentially inductive I, and, by the implementation of materials and forms allowing the transmission of a couple clamping said substantially inductive portion I to said substantially capacitive portion C to allow the connection between said portions C and I of said spark plug 1 to be optimally performed both mechanically and electrically.
  • said tightening torque is, more particularly, transmitted to said base 2 of said spark plug 1, and this transmission of said tightening torque can be achieved either by the perimeter of said substantially inductive portion I (first embodiment of the device according to the invention, shown in FIGS. 2A, 2B, 3, and 4), or by the central core 8 of said essentially inductive part I (second embodiment of the device according to the invention shown in Figures 5, 6A and 6B).
  • first embodiment of the device according to the invention shown in FIGS. 2A, 2B, 3, and 4
  • the central core 8 of said essentially inductive part I second embodiment of the device according to the invention shown in Figures 5, 6A and 6B.
  • FIGS. 2A and 2B are diagrammatic views in section, along the longitudinal axis Z of a radiofrequency plasma candle 1, variants of the first embodiment of the device according to the invention, in which the tightening torque for the embodiment the connection between said essentially capacitive portion C and said essentially inductive portion I of said spark plug 1 is transmitted by the perimeter of said substantially inductive portion I.
  • the main advantage of this type of transmission is that it reduces the mechanical stresses on the larger radius available, where the leverage effect is optimal, thus minimizing mechanical stress on the actual materials.
  • said transmission of said pair clamping said substantially inductive portion I to said substantially capacitive portion C then returns to transmitting a torque of said casing 6 to said cap 2.
  • FIG. 2A shows an embodiment of the invention in which said envelope 6 is metallic, thus also ensuring the aforementioned shielding role.
  • said envelope 6 can be made of different metallic materials and by various appropriate techniques; it may, in particular, by way of example and in a non-exhaustive manner, be carried out at the same time as the base 2 (by stamping or stamping), or be welded to said base 2 after separate production of the two parts (stamping of said base 2 and drawing / rolling of said envelope 6).
  • the thickness of said envelope 6 is small (as an indication, it is substantially less than or equal to 0.5 mm): in this case, said insulator 7 placed between said coil 5 and said envelope 6 is chosen from way that it contributes to the mechanical strength of the whole being in solid and incompressible form. In this case also, a connection by welding of said envelope 6 to said base 2 will be preferred.
  • the thickness of said envelope 6 is greater (typically it is substantially greater than or equal to 0.5 mm): in this case, the intrinsic mechanical strength of said envelope 6 is sufficient to mechanically ensure the transmission of a couple torsion to said base 2, and said insulator 7 can then be in the form of a pressurized gas or an insulating liquid with a low coefficient of expansion. In this case then, the realization of said envelope 6 and said base 2 in the same room will be preferred.
  • the inner face of said envelope 6 must be coated with a layer of a few tens of microns thick (typically 30 to 50 ⁇ m, for example) of a material with high electrical conductivity (for example non-restrictive way: silver or copper), in order to improve the radiofrequency conductivity of said envelope 6 and to limit losses by skin effect within it.
  • a material with high electrical conductivity for example non-restrictive way: silver or copper
  • the transmission of the tightening torque (torque here) of said substantially inductive portion I to said substantially capacitive portion C of said spark plug is obtained by the metal bond rigid made, during manufacture, between said casing 6 and said base 2, by one of the means described above (simultaneous manufacture of said casing and said base by stamping or stamping, or separate fabrications, then rigid assembly of said casing 6 and said base 2, for example by welding).
  • FIG. 2B shows an embodiment in which said envelope 6 is made of an insulating material of polymer type.
  • said envelope 6 must then have a relatively large thickness (substantially, and for example, of the order of a few millimeters) so as to allow the transmission of said pair Moreover, the material selected for producing said envelope 6 must, in this case, present a dielectric loss factor of the same order as that of the material of said insulator 7.
  • said insulator 7 can equally well consist of a pressurized gas or an insulating liquid with a low coefficient of expansion.
  • the outer face of said envelope 6 must, in this embodiment of the invention, be coated with a layer of a few tens of microns thickness (typically and by way of non-limiting example: 30 to 50 ⁇ m) of a material with high electrical conductivity (for example and without limitation: silver or copper): the application of this coating on the outer face, and not on the inner face, of said envelope 6 makes it possible to increase slightly the outside diameter of said essentially inductive part I, which improves the overvoltage coefficient of the resonator consisting of said parts C and I as previously described.
  • the transmission of the tightening torque between said essentially inductive part I and said essentially capacitive part C of said spark plug 1 is obtained by appropriate shaping of the interface between said base 2 and said envelope 6, two variants of which are shown in Figures 3 and 4.
  • FIG. 3 shows a mode of shaping said base 2 and said envelope 6 in which the part of said envelope 6 intended to come into contact with said base 2 has the shape of a male cavity 15, and a complementary female cavity 16 said male cavity 15 is made on the portion of said base 2 intended to come into contact with said envelope 6.
  • said male cavity 15 is made on the part of said base 2 intended to come into contact with said envelope 6, and said female cavity 16 complementary to said male cavity 15 is formed on the part of said envelope 6 intended to come into contact with said base 2.
  • said geometry of said male and female fingerprints 16 shown in FIGS. 3 and 4 is indicated by way of nonlimiting example, and that the shape of said fingerprints 15 and 16 is, in general, to be adjusted. in particular, depending on the materials used and the costs of production.
  • FIGS. 5, 6A and 6B are diagrammatic views in section along the longitudinal axis Z of a radiofrequency plasma candle 1 according to the invention, variants of the second embodiment of the device according to the invention, in which the tightening torque for the embodiment of the connection between said substantially capacitive portion C and said essentially inductive portion I of said spark plug 1 is transmitted by the central core of said substantially inductive portion I.
  • An important advantage of this mode of transmission is that it makes it possible to release the all of the outer space of said winding 5 of said substantially inductive portion I, and that it allows the use, for said insulator 7, of materials having significant coefficients of expansion with temperature.
  • said central element 8, around which said winding 5 is made is produced in the form of a mandrel having, in its part that is closest to said base 2, an enlarged portion 17 of complementary shape and dimension of the inner shape of the base 2, so as to be able to mechanically couple with said base 2.
  • the outer shape of said enlarged portion 17 may to be substantially polygonal, a cavity complementary to said substantially polygonal shape being formed in said base 2.
  • a connecting element (not shown in FIG.
  • this element may, for example and non-exhaustively, be a key inserted substantially parallel to the longitudinal axis Z of said spark plug 1 according to the invention, or a pin inserted substantially perpendicularly to said longitudinal axis Z of said spark plug 1.
  • a rounded shape will be preferred at a sharp angle at the level of the widening 17 of said central element 8, so as to limit the mechanical stresses and the risks of electromagnetic breakdown in this zone.
  • the shielding function previously mentioned, and provided by said envelope 6 can be obtained by various means, illustrated by FIGS. 6A and 6B.
  • FIG. 6A shows an embodiment in which said envelope 6 surrounding said insulator 7 placed around said winding 5 is a sheet of a few tens of microns thick (typically and not limited to 75 to 150 ⁇ m) made of a material having a high electrical conductivity, or covered, on its face in contact with said insulator 7, with a conductive thin layer of a material having a high electrical conductivity (for example and without limitation: silver or copper) , so as to preserve, as already described above, the electromagnetic quality of the assembly.
  • a sheet of a few tens of microns thick typically and not limited to 75 to 150 ⁇ m
  • a material having a high electrical conductivity for example and without limitation: silver or copper
  • said envelope 6 is preferably wound in a polygonal shape around said insulator 7: said insulator 7 can thus expand by converging towards a substantially cylindrical external shape without inducing mechanical stress additional on the perimeter of said envelope 6.
  • FIG. 6B shows an alternative embodiment, in which said envelope 6 is replaced by the deposition, on the outer surface of said insulator 7, of a conductive thin layer 18 (for example and without limitation, a layer of 30 to 50 ⁇ m thick) of a material having a high electrical conductivity (silver or copper, for example and without limitation).
  • a conductive thin layer 18 for example and without limitation, a layer of 30 to 50 ⁇ m thick
  • a material having a high electrical conductivity silver or copper, for example and without limitation
  • said thin conductive layer 18 may be deposited on a polymer film itself vacuum-plated on said insulator 7.
  • said thin conductive layer 18 will be protected from the outside, and, in particular, oxidation or corrosion phenomena that can degrade its electrical performance, by a conductive thin layer of a suitable barrier material (for example and without limitation: a layer of varnish or a polymer film).
  • the electrical continuity of the assembly of said spark plug 1 according to the invention is finalized by said connecting element 13 intended for the connection of said connector 12 to the power supply of said spark plug 1.
  • said element 13, bound in a rigid form, in particular, to said envelope 6 (for example and in a nonlimiting manner, thanks to a means of the type of those just described for the connection of said envelope 6 with said base 2), has a shape adapted to the use of a simple clamping tool for the introduction and tightening of said spark plug 1 in the cylinder head of the engine.
  • a spark plug according to the invention can be put in place and removed from its access well without the need to slide a specific tool around said candle: it is therefore not necessary to provide, in said access shaft to said candle, a space necessary for the passage of said specific tool and used only for the assembly and disassembly operations of said candle.

Abstract

The plug has a capacitive part (C) and an inductive part (I) connected in series to form a resonator. The parts are connected mechanically and electrically by a connection unit (13). The part (I) has a wire core (8) to transmit a tightening torque, for connecting the parts, to a shell (2) composed by the part (C). The wire core has an enlarged part with shape and dimension complementary to inner shape of the shell. The inductive part has an envelope (6) whose outer surface covered with a layer of thickness about 30 to 50 micrometer of a material having high electrical conductivity, so that outer diameter of the inductive part is slightly increased.

Description

Les impératifs d'accroissement de rendement et de diminution de la pollution génèrent des contraintes de plus en plus importantes sur l'architecture des moteurs. Ces contraintes se traduisent en particulier, pour le système d'allumage, par des dimensions de bougie de plus en plus réduites, ainsi que par une réduction des dimensions radiales du puits d'accès à ladite bougie, ce, afin de pouvoir, notamment, augmenter l'espace disponible dans la culasse pour permettre le passage de nouveaux canaux de refroidissement : la réduction de l'espace alloué à la bougie et à son puits d'accès a conduit, entre autres, à la réalisation de bobines de type "crayon" placées directement dans ledit puits d'accès à la bougie.The imperatives of increasing efficiency and reducing pollution generate increasingly significant constraints on the architecture of the engines. These constraints are reflected in particular, for the ignition system, spark plug dimensions increasingly reduced, as well as a reduction in the radial dimensions of the access well to said candle, in order to be able, in particular, increase the space available in the cylinder head to allow the passage of new cooling channels: the reduction of the space allocated to the candle and its access well led, among other things, to the realization of coils of the "pencil" type "placed directly in said access shaft to the candle.

Néanmoins, en raison, d'une part, de la différence de durée de vie entre la bougie proprement dite et sa bobine, ainsi que, d'autre part, des objectifs de standardisation des composants (chaque type de moteur nécessite en effet une bougie spécifiquement adaptée, alors qu'un type de bobine de ladite bougie peut être commun à plusieurs types de moteurs), la bougie et sa bobine sont, le plus souvent, séparées, et la seule liaison existant entre elles est alors de type électrique, le maintien mécanique de chacun de ces deux éléments étant assuré de manière indépendante, y compris dans le cas des bobines "crayon" précédemment mentionnées.However, due, on the one hand, to the difference in service life between the actual spark plug and its coil, as well as, on the other hand, to the standardization objectives of the components (each engine type requires a candle specifically adapted, while a type of coil of said spark plug may be common to several types of engines), the spark plug and its coil are, in most cases, separated, and the only link existing between them is then of the electric type, the mechanical maintenance of each of these two elements being provided independently, including in the case of "pencil" coils previously mentioned.

Par ailleurs, suivant un mode de montage bien connu dans l'état de la technique, le couple de serrage de la bougie est généralement appliqué sur le culot de ladite bougie, ledit culot comportant, classiquement, un filetage mâle destiné à coopérer avec un filetage femelle complémentaire réalisé dans la culasse, ainsi qu'un élément destiné au serrage contrôlé dudit assemblage fileté. Un tel mode de montage nécessite alors l'utilisation d'un outil spécifique que l'on glisse, autour de ladite bobine et de ladite bougie, dans ledit puits d'accès à ladite bougie : une telle configuration impose donc, notamment, qu'il existe, autour de ladite bobine et dans ledit puits d'accès à ladite bougie, un espace libre inutilisé en dehors des opérations de montage et de démontage de la bougie. Or l'existence d'un tel espace va à l'encontre des contraintes dimensionnelles précédemment évoquées.Furthermore, according to a mounting method well known in the state of the art, the tightening torque of the spark plug is generally applied to the base of said spark plug, said cap comprising, conventionally, a male thread intended to cooperate with a thread. complementary female made in the cylinder head, and an element for the controlled tightening of said threaded assembly. Such a mounting method then requires the use of a specific tool that is slid around said coil and said spark plug, in said access well to said spark plug: such a configuration therefore imposes, in particular, that there is, around said coil and in said access shaft to said candle, an unused free space outside the assembly operations and disassembly of the candle. However, the existence of such a space goes against the dimensional constraints previously mentioned.

Dans tout ce qui suit, on désignera par "inférieure" la partie d'une bougie d'allumage destinée à être la plus proche de la chambre de combustion d'un moteur à combustion interne, et par "supérieure" la partie opposée de ladite bougie.In what follows, the part of a spark plug intended to be the closest to the combustion chamber of an internal combustion engine will be referred to as "lower" and the "opposite" part of candle.

On désignera également par « couche mince conductrice » d'un matériaux présentant une forte conductivité électrique, une couche métallique d'un matériaux amagnétique d'une épaisseur au moins égale ou supérieure à l'épaisseur de peau dans le domaine de fréquence considéré, c'est-à-dire entre 1 Mégahertz et 10 Mégahertz, garantissant une fonction de blindage électromagnétique. La forte conductivité électrique des matériaux sera analogue à celle du cuivre ou de l'argent, matériaux de référence dans ce domaine (la valeur de la conductivité électrique du cuivre est de 5,9 x 107 Siemens par Mètre et celle de l'argent est supérieure à celle du cuivre).The term "conductive thin layer" of a material having a high electrical conductivity will also denote a metal layer of non-magnetic material having a thickness at least equal to or greater than the skin thickness in the frequency domain under consideration. that is, between 1 Megahertz and 10 Megahertz, ensuring an electromagnetic shielding function. The high electrical conductivity of the materials will be similar to that of copper or silver, reference materials in this field (the value of the electrical conductivity of copper is 5.9 x 10 7 Siemens per meter and that of silver is greater than that of copper).

On connaît différents modes de montage d'une bougie et de sa bobine dans lesquels l'espace réservé autour de l'ensemble pour le passage d'un outil destiné au montage mécanique de ladite bougie sur la culasse du moteur est réduit au minimum.Various methods of mounting a spark plug and its coil are known in which the space reserved around the assembly for the passage of a tool intended for mechanical mounting of said spark plug on the cylinder head of the engine is reduced to a minimum.

Le document EP1249907 présente ainsi, par exemple, un procédé de montage d'une bougie et de sa bobine dans lequel le puits d'accès à la bougie est constitué d'un certain nombre de trous lisses, sensiblement cylindriques, concentriques, et dont les diamètres respectifs sont adaptés de manière à former au moins un siège sensiblement perpendiculaire à l'axe dudit puits, une surface d'appui de ladite bougie perpendiculaire à l'axe commun à ladite bougie et audit puits d'accès venant en appui sur ledit siège, le positionnement de ladite bougie étant réalisé par l'intermédiaire d'un élément saillant situé sur la partie inférieure de ladite bougie et destiné à coopérer avec un usinage complémentaire réalisé dans les parois dudit puits d'accès. Dans le dispositif présenté par le document EP1249907 , un capuchon, constitué d'une partie tubulaire sensiblement cylindrique terminée par une bride sensiblement plane dont le diamètre extérieur est supérieur au diamètre dudit puits d'accès et dont la surface est sensiblement perpendiculaire à l'axe de ladite partie tubulaire et dudit puits d'accès, vient alors se placer sur la partie supérieure de la bougie. Les dimensions dudit capuchon sont ajustées de manière que, lorsque ladite bride sensiblement plane est en appui sur la face supérieure dudit puits d'accès à la bougie, l'extrémité de la partie tubulaire dudit capuchon vient en appui sur une partie de ladite bougie, assurant ainsi un maintien en compression de ladite bougie dans son puits d'accès : le serrage de l'ensemble est réalisé par vissage de ladite bride sensiblement plane sur ladite face supérieure de ladite chambre de combustion. Dans le dispositif présenté par le document EP1249907 , la bobine est en outre intégrée audit capuchon, le contact électrique entre ladite bobine et ladite bougie étant réalisé au moyen d'un ressort hélicoïdal mis en compression lors du positionnement dudit capuchon.The document EP1249907 Thus, for example, a method of mounting a spark plug and its spool in which the spark plug access hole is made up of a number of smooth, substantially cylindrical, concentric holes, the respective diameters of which are adapted to form at least one seat substantially perpendicular to the axis of said well, a bearing surface of said candle perpendicular to the axis common to said spark plug and said access shaft bearing on said seat, the positioning said spark plug being produced by means of a projecting element located on the lower part of said spark plug and intended to cooperate with a complementary machining performed in the walls of said access well. In the device presented by the document EP1249907 a cap consisting of a substantially cylindrical tubular portion terminated by a substantially planar flange whose outer diameter is greater than the diameter of said access well and whose surface is substantially perpendicular to the axis of said tubular portion and said well; access, is then placed on the upper part of the candle. The dimensions of said cap are adjusted so that, when said substantially flat flange bears against the upper face of said candle access well, the end of the tubular portion of said cap bears against a portion of said spark plug, thus ensuring a compression hold of said spark plug in its access well: the tightening of the assembly is achieved by screwing said substantially flat flange on said upper face of said combustion chamber. In the device presented by the document EP1249907 , the coil is further integrated in said cap, the electrical contact between said coil and said spark plug being made by means of a helical spring placed in compression during the positioning of said cap.

Un tel dispositif, s'il permet de s'affranchir de la nécessité de ménager un espace spécifiquement destiné au passage d'un outil de serrage dans le puits d'accès à la bougie, impose toutefois la réalisation d'un nombre important de pièces de précision.Such a device, if it eliminates the need to provide a space specifically for the passage of a clamping tool in the access well to the candle, however requires the achievement of a large number of parts precision.

Il n'est, en outre, qu'imparfaitement adapté à des bougies à plasma radiofréquence, notamment en raison du mode de liaison entre la bougie et sa bobine retenu.It is, moreover, only imperfectly adapted to radiofrequency plasma candles, in particular because of the mode of connection between the candle and its retained coil.

De même, la publication EP0969575 propose une bougie associée à une bobine. La bougie de cette publication est un modèle de bougie classique à étincelle et ne comporte aucune partie capacitive comme sur les bougies à plasma radiofréquence.Similarly, publication EP0969575 proposes a candle associated with a coil. The candle in this publication is a classic spark plug model and does not have any capacitive parts, such as radiofrequency plasma candles.

En effet, une bougie à plasma radiofréquence comporte généralement une partie supérieure, essentiellement inductive, principalement constituée de la bobine de ladite bougie et d'une enveloppe formant blindage de ladite partie essentiellement inductive, et une partie inférieure essentiellement capacitive composée principalement d'une structure coaxiale, l'ensemble se comportant comme un résonateur LC. Or, il est connu que la continuité et la qualité de la liaison électrique entre les différents composants d'un tel résonateur jouent un rôle capital dans l'optimisation de ses performances. Par ailleurs, les dimensions desdits éléments dudit résonateur doivent être définies, en fonction du domaine de fonctionnement en radiofréquence, de manière à optimiser les performances dudit résonateur : en particulier, la longueur de ladite partie essentiellement capacitive doit être aussi réduite que possible, afin que la valeur de la capacité reste faible ; en outre, le diamètre de ladite partie essentiellement inductive doit être aussi élevé que possible, afin que la valeur du coefficient de surtension du résonateur ainsi constitué soit optimale. Ces contraintes impliquent alors de revoir le mode de réalisation et de montage des éléments de l'ensemble constituant le résonateur précédemment évoqué.Indeed, a radiofrequency plasma spark plug generally comprises an upper part, essentially inductive, consisting mainly of the coil of said spark plug and a shielding jacket of said essentially inductive portion, and a substantially capacitive lower portion composed mainly of a structure coaxial, the whole behaving like an LC resonator. However, it is known that the continuity and quality of the electrical connection between the different components of such a resonator play a vital role in optimizing its performance. Moreover, the dimensions of said elements of said resonator must be defined, as a function of the radiofrequency operating domain, so as to optimizing the performance of said resonator: in particular, the length of said substantially capacitive portion should be as small as possible, so that the value of the capacitance remains low; in addition, the diameter of said substantially inductive portion should be as high as possible, so that the value of the overvoltage coefficient of the resonator thus formed is optimal. These constraints then involve reviewing the embodiment and assembly of the elements of the assembly constituting the previously mentioned resonator.

Le document DE-C-19 723 784 décrit une bougie d'allumage, selon le préambule de la revendication 1.The document DE-C-19 723 784 discloses a spark plug according to the preamble of claim 1.

La présente invention a pour but de proposer un dispositif d'assemblage dans lequel la liaison entre la bobine et les autres éléments constituant la bougie assure à la fois la continuité électrique et un couplage mécanique, tout en permettant la mise en place de l'ensemble ainsi constitué sans avoir à glisser un outil autour de ladite bobine pour venir prendre appui sur le culot de ladite bougie.The object of the present invention is to propose an assembly device in which the connection between the coil and the other elements constituting the spark plug ensures both electrical continuity and mechanical coupling, while allowing the assembly to be put in place. thus constituted without having to slide a tool around said coil to come to bear on the base of said candle.

Préférentiellement l'invention s'applique à une bougie d'allumage à plasma radiofréquence.Preferably, the invention applies to a radiofrequency plasma spark plug.

L'invention atteint son but grâce à une bougie d'allumage selon la revendication 1.The invention achieves its goal by means of a spark plug according to claim 1.

Selon l'invention, ladite partie essentiellement capacitive de ladite bougie d'allumage comporte, notamment, un culot entourant une électrode centrale sensiblement cylindrique et jouant le rôle d'électrode haute tension, et ladite partie essentiellement inductive de ladite bougie est réalisée dans un ou plusieurs matériaux et a une configuration permettant de transmettre un couple de serrage audit culot de ladite bougie.According to the invention, said essentially capacitive portion of said spark plug comprises, in particular, a base surrounding a substantially cylindrical central electrode and acting as a high voltage electrode, and said essentially inductive part of said spark plug is made in one or several materials and has a configuration for transmitting a torque to said base of said candle.

Avantageusement, ledit culot présente, sur la face extérieure de sa partie la plus proche de la culasse dudit moteur à combustion interne équipé de ladite bougie d'allumage, une forme appropriée pour la mise en place et le serrage de ladite bougie d'allumage sur ladite culasse ; ladite bougie d'allumage comportant, en outre, à son extrémité opposée à son extrémité la plus proche de ladite culasse, un élément de connexion solidaire d'un dispositif de connexion, ledit élément de connexion présentant une forme adaptée permettant, grâce à ladite transmission, de ladite partie essentiellement inductive audit culot, d'un couple de serrage, l'utilisation d'un outil simple et peu encombrant pour la mise en place et le serrage de ladite bougie d'allumage sur ladite culasse dudit moteur à combustion.Advantageously, said base has, on the outer face of its part closest to the cylinder head of said internal combustion engine equipped with said spark plug, a suitable shape for the introduction and tightening of said spark plug on said cylinder head; said spark plug further comprising, at its end opposite its nearest end of said yoke, a connection element integral with a connecting device, said connecting element having a suitable shape enabling, by virtue of said transmission of said substantially inductive portion to said base, a tightening torque, the use of a simple and compact tool for the introduction and tightening of said spark plug on said cylinder head of said engine.

Avantageusement, ledit couple de serrage est transmis par le périmètre de ladite partie essentiellement inductive de ladite bougie et l'invention peut alors présenter une ou plusieurs des caractéristiques suivantes :

  • ladite enveloppe de ladite partie essentiellement inductive est une feuille métallique mince, soudée audit culot de ladite bougie d'allumage, réalisée dans un matériau présentant une forte conductivité électrique ou revêtue, sur sa face intérieure, d'une couche mince conductrice d'un matériau présentant une forte conductivité électrique,
  • ladite enveloppe de ladite partie essentiellement inductive et ledit culot de ladite bougie sont réalisés en une unique pièce métallique, dans un matériau présentant une forte conductivité électrique ou revêtue, sur la face intérieure, d'une couche mince conductrice d'un matériau présentant une forte conductivité électrique,
  • ladite enveloppe de ladite partie essentiellement inductive est un manchon réalisé en matériau polymère, revêtu, sur sa face extérieure, d'une couche mince conductrice d'un matériau présentant une forte conductivité électrique,
  • ladite enveloppe est réalisée en matériau polymère, et la partie dudit culot destinée à être en contact avec ladite enveloppe comporte une empreinte complémentaire de l'empreinte réalisée sur la section de l'enveloppe ; dans cette configuration, la couche mince conductrice s'étend jusqu'à l'empreinte réalisée sur la section de l'enveloppe, de manière à assurer un contact électrique entre les deux empreintes.
  • Alternativement, ledit couple de serrage est transmis par l'âme centrale de ladite partie essentiellement inductive de ladite bougie, et l'invention peut alors présenter une ou plusieurs des caractéristiques suivantes :
  • ladite âme centrale de ladite partie essentiellement inductive a la forme d'un mandrin présentant un diamètre élargi dans sa partie proche du culot de ladite bougie,
  • ledit mandrin est réalisé dans un matériau isolant,
  • ledit mandrin présente, dans sa partie proche dudit culot de ladite bougie, une forme sensiblement polygonale, et la forme complémentaire de cette forme sensiblement polygonale est réalisée dans le culot de ladite bougie,
  • une troisième pièce est insérée radialement dans un logement commun audit mandrin et audit culot de ladite bougie,
  • ladite troisième pièce est un pion inséré dans ledit logement commun selon une direction sensiblement perpendiculaire audit axe commun à ladite âme centrale de ladite partie essentiellement inductive et audit culot de ladite bougie,
  • ladite troisième pièce est une clavette inséré dans ledit logement commun selon une direction sensiblement parallèle audit axe commun à ladite âme centrale de ladite partie essentiellement inductive et audit culot de ladite bougie,
  • un manchon isolant est placé autour de ladite âme centrale de ladite partie essentiellement inductive, et la face extérieure dudit manchon isolant est revêtue d'une couche mince conductrice d'un matériau présentant une forte conductivité électrique,
  • ladite couche mince conductrice d'un matériau à forte conductivité électrique, déposée sur ledit manchon isolant, est protégée par une couche mince conductrice d'un matériau barrière, ou intégrée à un film polymère appliqué sous vide sur ladite face extérieure dudit manchon isolant.
Advantageously, said tightening torque is transmitted by the perimeter of said essentially inductive portion of said spark plug and the invention may then have one or more of the following characteristics:
  • said envelope of said substantially inductive part is a thin metal sheet, welded to said base of said spark plug, made of a material having a high electrical conductivity or coated on its inner face with a conductive thin layer of a material having a high electrical conductivity,
  • said envelope of said essentially inductive part and said base of said spark plug are made of a single metal part, of a material having a high electrical conductivity or coated, on the inner face, a conductive thin layer of a material having a high electrical conductivity,
  • said envelope of said essentially inductive part is a sleeve made of polymer material, coated on its outer face with a conductive thin layer of a material having a high electrical conductivity,
  • said envelope is made of polymeric material, and the portion of said base intended to be in contact with said envelope has a complementary imprint of the impression made on the section of the envelope; in this configuration, the conductive thin layer extends to the imprint made on the section of the envelope, so as to ensure electrical contact between the two cavities.
  • Alternatively, said tightening torque is transmitted by the central core of said essentially inductive portion of said spark plug, and the invention may then have one or more of the following characteristics:
  • said central core of said essentially inductive portion is in the form of a mandrel having an enlarged diameter in its part near the base of said spark plug,
  • said mandrel is made of an insulating material,
  • said mandrel has, in its near part of said cap of said candle, a substantially polygonal shape, and the complementary shape of this substantially polygonal shape is formed in the base of said candle,
  • a third piece is inserted radially into a housing common to said mandrel and to said base of said candle,
  • said third piece is a pin inserted into said common housing in a direction substantially perpendicular to said axis common to said central core of said substantially inductive portion and said base of said candle,
  • said third piece is a key inserted into said common housing in a substantially parallel direction said axis common to said central core of said substantially inductive portion and said base of said candle,
  • an insulating sleeve is placed around said central core of said essentially inductive part, and the outer face of said insulating sleeve is coated with a conductive thin layer of a material having a high electrical conductivity,
  • said conductive thin layer of a material with high electrical conductivity, deposited on said insulating sleeve, is protected by a conductive thin layer of a barrier material, or integrated in a vacuum-applied polymer film on said outer face of said insulating sleeve.

D'autres caractéristiques et avantages de l'invention ressortiront à la lecture de la description qui suit, en référence aux dessins annexés dans lesquels l'invention est décrite dans son application à une bougie à plasma radiofréquence et dans lesquels:

  • la figure 1 est une vue en coupe schématique selon son axe longitudinal de ladite bougie à plasma radiofréquence,
  • les figures 2A et 2B sont des vues schématiques en coupe selon son axe longitudinal d'un mode de réalisation préféré de l'invention dans lequel le couple de serrage est transmis par le périmètre de ladite partie essentiellement inductive,
  • les figures 3 et 4 sont des vues en perspective du culot de la bougie et de l'enveloppe de la partie essentiellement inductive selon deux variantes du mode de réalisation présenté par la figure 2B,
  • la figure 5 est une vue schématiques en coupe selon son axe longitudinal d'un mode de réalisation alternatif de l'invention dans lequel le couple de serrage est transmis par l'âme centrale de ladite partie essentiellement inductive,
  • les figures 6A et 6B sont des vues schématiques en coupe selon son axe longitudinal de deux variantes du mode de réalisation alternatif de l'invention présenté par la figure 5.
Other characteristics and advantages of the invention will emerge on reading the description which follows, with reference to the appended drawings in which the invention is described in its application to a radiofrequency plasma candle and in which:
  • FIG. 1 is a diagrammatic sectional view along its longitudinal axis of said radiofrequency plasma candle,
  • FIGS. 2A and 2B are diagrammatic views in section along its longitudinal axis of a preferred embodiment of the invention in which the tightening torque is transmitted by the perimeter of said essentially inductive portion,
  • FIGS. 3 and 4 are perspective views of the base of the spark plug and the casing of the essentially inductive portion according to two variants of the embodiment shown in FIG. 2B,
  • FIG. 5 is a schematic sectional view along its longitudinal axis of an alternative embodiment of the invention in which the tightening torque is transmitted by the central core of said essentially inductive part,
  • FIGS. 6A and 6B are schematic views in section along its longitudinal axis of two variants of the alternative embodiment of the invention presented in FIG. 5.

Dans ce qui suit, un même élément sera repéré par la même notation sur l'ensemble des figures.In what follows, the same element will be marked by the same notation on all the figures.

Ainsi que le montre la figure 1 et comme il a été précédemment décrit, une bougie à plasma radiofréquence 1 de forme générale sensiblement cylindrique comporte principalement une partie inférieure essentiellement capacitive C et une partie supérieure essentiellement inductive I, lesdites parties C et I étant de forme sensiblement allongée, connectées en série et comportant un axe longitudinal commun Z.As shown in FIG. 1 and as previously described, a radiofrequency plasma plug 1 of substantially cylindrical general shape mainly comprises a substantially capacitive lower part C and an essentially inductive upper part I, said parts C and I being of shape. substantially elongated, connected in series and having a common longitudinal axis Z.

Ladite partie essentiellement capacitive C comporte, notamment, un culot 2 destiné à être relié à la masse et entourant une électrode centrale 3, sensiblement cylindrique, d'axe Z, jouant le rôle d'électrode haute tension. Un isolant 4 est placé entre le culot 2 et l'électrode centrale 3, ledit isolant 4 étant configuré de manière à guider les étincelles entre les électrodes 2 et 3. D'une manière bien connue dans l'état de la technique, ledit culot 2 présente, sur la face extérieure de sa partie inférieure la plus proche de la culasse du moteur à combustion interne équipé de ladite bougie 1, une forme appropriée à la mise en place, au maintien et au serrage de ladite bougie 1 sur ladite culasse (par exemple et de manière non limitative, ainsi que représenté sur la figure 1 : un filetage).Said substantially capacitive portion C comprises, in particular, a base 2 intended to be connected to the ground and surrounding a central electrode 3, substantially cylindrical, axis Z, acting as a high voltage electrode. An insulator 4 is placed between the base 2 and the central electrode 3, said insulator 4 being configured to guide the sparks between the electrodes 2 and 3. In a manner well known in the state of the art, said base 2 has, on the outer face of its lower part closest to the cylinder head of the internal combustion engine equipped with said spark plug 1, a shape suitable for placing, holding and tightening said spark plug 1 on said cylinder head ( for example and without limitation, as shown in Figure 1: a thread).

Ladite partie essentiellement inductive I de ladite bougie 1 comporte, pour sa part, un bobinage 5 dont l'axe est avantageusement sensiblement confondu avec l'axe Z de l'électrode centrale 3 et de la bougie 1. Ledit bobinage 5 est, par ailleurs, entouré d'une enveloppe 6, de préférence réalisée dans un matériau conducteur amagnétique, destinée à réduire les émissions électromagnétiques de ladite bougie 1 et à jouer le rôle de blindage, les dimensions de ladite enveloppe 6 étant calculées de manière à minimiser les risques de claquage entre ledit bobinage 5 et ladite enveloppe 6. Avantageusement, afin de réduire encore les risques de claquage, sources de dissipations parasites d'énergie, un isolant 7 est placé entre ledit bobinage 5 et ladite enveloppe 6, et ledit bobinage 5 est réalisé autour d'un élément plein 8 réalisé dans un matériau isolant amagnétique. Dans le mode de réalisation de la bougie à plasma radiofréquence présenté sur la figure 1, un isolant complémentaire 9 est en outre placé entre ledit isolant 7 et ledit isolant 4 séparant ledit culot 2 et ladite électrode centrale 3, une pièce 10 reliée électriquement audit culot 2 assurant la liaison entre le maintien desdits isolants 4, 7, et 9.Said essentially inductive part I of said spark plug 1 comprises, for its part, a winding 5 whose axis is advantageously substantially coincident with the axis Z of the central electrode 3 and the spark plug 1. Said winding 5 is, moreover surrounded by an envelope 6, preferably made of a nonmagnetic conductive material, intended to reduce the electromagnetic emissions of said spark plug 1 and to act as a shield, the dimensions of said envelope 6 being calculated so as to minimize the risks of breakdown between said winding 5 and said envelope 6. Advantageously, in order to further reduce the risks of breakdown, sources of parasitic energy dissipation, an insulator 7 is placed between said winding 5 and said envelope 6, and said winding 5 is made around a solid element 8 made of a non-magnetic insulating material. In the embodiment of the radiofrequency plasma candle shown in FIG. 1, a complementary insulator 9 is furthermore placed between said insulator 7 and said insulator 4 separating said base 2 and said central electrode 3, a part 10 electrically connected to said base 2 ensuring the connection between the holding of said insulators 4, 7, and 9.

Les matériaux et modes de réalisation et d'assemblage de ces différents éléments sont définis et mis en oeuvre de manière à limiter au maximum toute inclusion d'air au niveau des interfaces, également sources de claquages et de pertes.The materials and embodiments and assembly of these various elements are defined and implemented so as to minimize any inclusion of air at the interfaces, also sources of breakdowns and losses.

Un enroulement de mesure de courant 11 est également généralement réalisé autour dudit bobinage 5, et un dispositif de connexion 13, solidaire d'un connecteur 12 (non détaillés sur les figures), est placé à l'extrémité supérieure de ladite bougie 1. Une extrémité dudit bobinage 5 est reliée audit connecteur 12, l'autre extrémité dudit bobinage 5 étant reliée par des moyens appropriés 14 (non détaillés sur les figures) à une extrémité interne de ladite électrode centrale 3.A current measuring winding 11 is also generally made around said winding 5, and a connection device 13, integral with a connector 12 (not detailed in the figures), is placed at the upper end of said candle 1. A end of said coil 5 is connected to said connector 12, the other end of said coil 5 being connected by appropriate means 14 (not detailed in the figures) to an inner end of said central electrode 3.

Ainsi qu'il a été mentionné précédemment, une telle bougie 1 se comporte comme un résonateur LC, dans lequel la partie capacitive et la partie inductive sont placées en série, et dans lequel la partie capacitive C est composée par le culot 2, l'électrode centrale 3, l'isolant 4 placé entre ladite électrode centrale 3 et ledit culot 2, et par les capacités parasites internes liées à la géométrie de ladite bougie 1, la partie essentiellement inductive I étant principalement constituée par le bobinage 5, l'isolant 7 et l'enveloppe 6.As mentioned above, such a candle 1 behaves like an LC resonator, in which the capacitive part and the inductive part are placed in series, and in which the capacitive part C is composed by the base 2, the central electrode 3, the insulator 4 placed between said central electrode 3 and said base 2, and by the internal parasitic capacitances related to the geometry of said spark plug 1, the essentially inductive part I consisting mainly of the winding 5, the insulator 7 and the envelope 6.

Afin de réduire au maximum lesdites capacités parasites (ainsi qu'il a été mentionné plus haut, les performances du résonateur ainsi constitué sont d'autant meilleures que la valeur de la capacité de ladite partie capacitive est faible), la longueur de la liaison entre ladite partie essentiellement capacitive C et ladite partie essentiellement inductive I doit être réduite autant que possible. De même, le coefficient de surtension du résonateur LC constitué par ladite partie essentiellement inductive I et ladite partie essentiellement capacitive C placées en série est d'autant meilleur que le diamètre de ladite partie essentiellement inductive I est élevé. Enfin, la qualité électrique de ladite liaison entre lesdites parties essentiellement capacitive C et inductive I (continuité électrique, en particulier) doit également être maximale afin d'optimiser les performances dudit résonateur.In order to reduce these parasitic capacitances as much as possible (as mentioned above, the performances of the resonator thus constituted are all the better as the capacitance value of said capacitive part is small), the length of the connection between said substantially capacitive portion C and said substantially inductive portion I should be reduced as much as possible. Similarly, the overvoltage coefficient of the resonator LC constituted by said substantially inductive portion I and said substantially capacitive portion C placed in series is even better than the diameter of said substantially inductive portion I is high. Finally, the electrical quality of said connection between said substantially capacitive C and inductive I portions (continuity electrical, in particular) must also be maximum in order to optimize the performance of said resonator.

Le dispositif selon l'invention propose d'introduire un mode de liaison rigide entre certains des éléments de chacune des parties essentiellement capacitive C et essentiellement inductive I, et, par la mise en oeuvre de matériaux et de formes permettant la transmission d'un couple de serrage de ladite partie essentiellement inductive I à ladite partie essentiellement capacitive C, de permettre que la liaison entre lesdites parties C et I de ladite bougie 1 puisse être réalisée de manière optimale tant sur le plan mécanique que sur le plan électrique.The device according to the invention proposes to introduce a rigid connection mode between some of the elements of each of the essentially capacitive parts C and essentially inductive I, and, by the implementation of materials and forms allowing the transmission of a couple clamping said substantially inductive portion I to said substantially capacitive portion C to allow the connection between said portions C and I of said spark plug 1 to be optimally performed both mechanically and electrically.

Ainsi qu'il va maintenant être décrit, ledit couple de serrage est, plus particulièrement, transmis audit culot 2 de ladite bougie d'allumage 1, et cette transmission dudit couple de serrage peut être réalisée soit par le périmètre de ladite partie essentiellement inductive I (premier mode de réalisation du dispositif selon l'invention, présenté par les figures 2A, 2B, 3, et 4), soit par l'âme centrale 8 de ladite partie essentiellement inductive I (second mode de réalisation du dispositif selon l'invention, présenté par les figures 5, 6A et 6B). De plus, en fonction de la nature des matériaux choisis, et, en particulier, en fonction des propriétés thermomécaniques notamment dudit isolant 7, plusieurs variantes de chacun des modes de réalisation de l'invention sont envisageables.As will now be described, said tightening torque is, more particularly, transmitted to said base 2 of said spark plug 1, and this transmission of said tightening torque can be achieved either by the perimeter of said substantially inductive portion I (first embodiment of the device according to the invention, shown in FIGS. 2A, 2B, 3, and 4), or by the central core 8 of said essentially inductive part I (second embodiment of the device according to the invention shown in Figures 5, 6A and 6B). In addition, depending on the nature of the materials chosen, and in particular, depending on the thermomechanical properties including said insulation 7, several variants of each of the embodiments of the invention are possible.

Les figures 2A et 2B sont des vues schématiques en coupe, selon l'axe longitudinal Z d'une bougie à plasma radiofréquence 1, des variantes du premier mode de réalisation du dispositif selon l'invention, dans lequel le couple de serrage pour la réalisation de la liaison entre ladite partie essentiellement capacitive C et ladite partie essentiellement inductive I de ladite bougie 1 est transmis par le périmètre de ladite partie essentiellement inductive I. L'avantage principal de ce type de transmission est qu'il ramène les contraintes mécaniques sur le plus grand rayon disponible, à l'endroit où l'effet de bras de levier est optimal, minimisant ainsi les contraintes mécaniques sur les matériaux proprement dits. Dans ce mode de réalisation de l'invention, ladite transmission dudit couple de serrage de ladite partie essentiellement inductive I à ladite partie essentiellement capacitive C revient alors à la transmission d'un couple de torsion de ladite enveloppe 6 audit culot 2.FIGS. 2A and 2B are diagrammatic views in section, along the longitudinal axis Z of a radiofrequency plasma candle 1, variants of the first embodiment of the device according to the invention, in which the tightening torque for the embodiment the connection between said essentially capacitive portion C and said essentially inductive portion I of said spark plug 1 is transmitted by the perimeter of said substantially inductive portion I. The main advantage of this type of transmission is that it reduces the mechanical stresses on the larger radius available, where the leverage effect is optimal, thus minimizing mechanical stress on the actual materials. In this embodiment of the invention, said transmission of said pair clamping said substantially inductive portion I to said substantially capacitive portion C then returns to transmitting a torque of said casing 6 to said cap 2.

La figure 2A présente un mode de réalisation de l'invention dans lequel ladite enveloppe 6 est métallique, assurant ainsi également le rôle de blindage précédemment évoqué. Selon des procédés industriels connus, ladite enveloppe 6 peut être réalisée dans différents matériaux métalliques et par différentes techniques appropriées ; elle peut, notamment, à titre d'exemple et de manière non exhaustive, être réalisée en même temps que le culot 2 (par matriçage ou emboutissage), ou être soudée audit culot 2 après réalisation séparée des deux pièces (matriçage dudit culot 2 et tréfilage/laminage de ladite enveloppe 6).FIG. 2A shows an embodiment of the invention in which said envelope 6 is metallic, thus also ensuring the aforementioned shielding role. According to known industrial processes, said envelope 6 can be made of different metallic materials and by various appropriate techniques; it may, in particular, by way of example and in a non-exhaustive manner, be carried out at the same time as the base 2 (by stamping or stamping), or be welded to said base 2 after separate production of the two parts (stamping of said base 2 and drawing / rolling of said envelope 6).

Deux variantes sont envisageables, selon l'épaisseur de ladite enveloppe 6.Two variants are possible, depending on the thickness of said envelope 6.

Dans une première variante, l'épaisseur de ladite enveloppe 6 est faible (à titre indicatif, elle est sensiblement inférieure ou égale à 0.5 mm) : dans ce cas, ledit isolant 7 placé entre ladite bobine 5 et ladite enveloppe 6 est choisi de telle manière qu'il contribue à la tenue mécanique de l'ensemble en étant sous forme solide et incompressible. Dans ce cas également, une liaison par soudure de ladite enveloppe 6 audit culot 2 sera préférée.In a first variant, the thickness of said envelope 6 is small (as an indication, it is substantially less than or equal to 0.5 mm): in this case, said insulator 7 placed between said coil 5 and said envelope 6 is chosen from way that it contributes to the mechanical strength of the whole being in solid and incompressible form. In this case also, a connection by welding of said envelope 6 to said base 2 will be preferred.

Dans une deuxième variante, l'épaisseur de ladite enveloppe 6 est plus importante (typiquement elle est sensiblement supérieure ou égale à 0.5 mm) : dans ce cas, la tenue mécanique intrinsèque de ladite enveloppe 6 suffit à assurer mécaniquement la transmission d'un couple de torsion audit culot 2, et ledit isolant 7 peut alors se présenter sous forme d'un gaz sous pression ou d'un liquide isolant à faible coefficient de dilatation. Dans ce cas alors, la réalisation de ladite enveloppe 6 et dudit culot 2 dans une même pièce sera préférée.In a second variant, the thickness of said envelope 6 is greater (typically it is substantially greater than or equal to 0.5 mm): in this case, the intrinsic mechanical strength of said envelope 6 is sufficient to mechanically ensure the transmission of a couple torsion to said base 2, and said insulator 7 can then be in the form of a pressurized gas or an insulating liquid with a low coefficient of expansion. In this case then, the realization of said envelope 6 and said base 2 in the same room will be preferred.

Dans ces deux variantes, la face intérieure de ladite enveloppe 6 doit être revêtue d'une couche de quelques dizaines de microns d'épaisseur (typiquement 30 à 50 µm, par exemple) d'un matériau à forte conductivité électrique (par exemple et de manière non limitative : de l'argent ou du cuivre), ce, afin d'améliorer la conductivité radiofréquence de ladite enveloppe 6 et de limiter les pertes par effet de peau au sein de celle-ci.In these two variants, the inner face of said envelope 6 must be coated with a layer of a few tens of microns thick (typically 30 to 50 μm, for example) of a material with high electrical conductivity (for example non-restrictive way: silver or copper), in order to improve the radiofrequency conductivity of said envelope 6 and to limit losses by skin effect within it.

Quelle que soit la variante choisie, dans ce mode de réalisation de l'invention, la transmission du couple de serrage (couple de torsion ici) de ladite partie essentiellement inductive I à ladite partie essentiellement capacitive C de ladite bougie est obtenue par la liaison métallique rigide réalisée, lors de la fabrication, entre ladite enveloppe 6 et ledit culot 2, par l'un des moyens décrits précédemment (fabrication simultanée de ladite enveloppe et dudit culot par matriçage ou emboutissage, ou fabrications séparées, puis assemblage rigide de ladite enveloppe 6 et dudit culot 2, par exemple par soudure).Whatever the variant chosen, in this embodiment of the invention, the transmission of the tightening torque (torque here) of said substantially inductive portion I to said substantially capacitive portion C of said spark plug is obtained by the metal bond rigid made, during manufacture, between said casing 6 and said base 2, by one of the means described above (simultaneous manufacture of said casing and said base by stamping or stamping, or separate fabrications, then rigid assembly of said casing 6 and said base 2, for example by welding).

La figure 2B présente un mode de réalisation dans lequel ladite enveloppe 6 est réalisée dans un matériau isolant de type polymère. Ces matériaux présentant une rigidité mécanique plus faible que les matériaux métalliques, ladite enveloppe 6 doit alors présenter une épaisseur relativement importante (sensiblement, et à titre d'exemple, de l'ordre de quelques millimètres) de manière à pouvoir permettre la transmission dudit couple de serrage audit culot 2. Par ailleurs, le matériau retenu pour la réalisation de ladite enveloppe 6 doit, dans ce cas, présenter un facteur de perte diélectrique du même ordre de que celui du matériau dudit isolant 7. Dans ce mode de réalisation de l'invention, ledit isolant 7 peut indifféremment être constitué d'un gaz sous pression ou d'un liquide isolant à faible coefficient de dilatation.FIG. 2B shows an embodiment in which said envelope 6 is made of an insulating material of polymer type. These materials having a lower mechanical rigidity than metal materials, said envelope 6 must then have a relatively large thickness (substantially, and for example, of the order of a few millimeters) so as to allow the transmission of said pair Moreover, the material selected for producing said envelope 6 must, in this case, present a dielectric loss factor of the same order as that of the material of said insulator 7. In this embodiment of According to the invention, said insulator 7 can equally well consist of a pressurized gas or an insulating liquid with a low coefficient of expansion.

Il est à noter que, afin d'assurer la fonction de blindage de ladite partie essentiellement inductive I, la face extérieure de ladite enveloppe 6 doit, dans ce mode de réalisation de l'invention, être revêtue d'une couche de quelques dizaines de microns d'épaisseur (typiquement et à titre d'exemple non limitatif : 30 à 50 µm) d'un matériau à forte conductivité électrique (par exemple et de manière non limitative : de l'argent ou du cuivre) : l'application de ce revêtement à la face extérieure, et non à la face intérieure, de ladite enveloppe 6 permet en effet alors d'augmenter légèrement le diamètre extérieur de ladite partie essentiellement inductive I, ce qui améliore le coefficient de surtension du résonateur constitué desdites parties C et I ainsi qu'il a été précédemment décrit.It should be noted that, in order to ensure the shielding function of said essentially inductive part I, the outer face of said envelope 6 must, in this embodiment of the invention, be coated with a layer of a few tens of microns thickness (typically and by way of non-limiting example: 30 to 50 μm) of a material with high electrical conductivity (for example and without limitation: silver or copper): the application of this coating on the outer face, and not on the inner face, of said envelope 6 makes it possible to increase slightly the outside diameter of said essentially inductive part I, which improves the overvoltage coefficient of the resonator consisting of said parts C and I as previously described.

Dans ce mode de réalisation de l'invention, la transmission du couple de serrage entre ladite partie essentiellement inductive I et ladite partie essentiellement capacitive C de ladite bougie 1 est obtenue par une mise en forme appropriée de l'interface entre ledit culot 2 et ladite enveloppe 6, dont deux variantes sont présentées par les figures 3 et 4.In this embodiment of the invention, the transmission of the tightening torque between said essentially inductive part I and said essentially capacitive part C of said spark plug 1 is obtained by appropriate shaping of the interface between said base 2 and said envelope 6, two variants of which are shown in Figures 3 and 4.

La figure 3 présente un mode de mise en forme dudit culot 2 et de ladite enveloppe 6 dans lequel la partie de ladite enveloppe 6 destinée à venir au contact dudit culot 2 a la forme d'une empreinte mâle 15, et une empreinte femelle 16 complémentaire de ladite empreinte mâle 15 est réalisée sur la partie dudit culot 2 destinée à venir au contact de ladite enveloppe 6.FIG. 3 shows a mode of shaping said base 2 and said envelope 6 in which the part of said envelope 6 intended to come into contact with said base 2 has the shape of a male cavity 15, and a complementary female cavity 16 said male cavity 15 is made on the portion of said base 2 intended to come into contact with said envelope 6.

Alternativement, et ainsi que le présente la figure 4, ladite empreinte mâle 15 est réalisée sur la partie dudit culot 2 destinée à venir au contact de ladite enveloppe 6, et ladite empreinte femelle 16 complémentaire de ladite empreinte mâle 15 est réalisée sur la partie de ladite enveloppe 6 destinée à venir au contact dudit culot 2.Alternatively, and as shown in FIG. 4, said male cavity 15 is made on the part of said base 2 intended to come into contact with said envelope 6, and said female cavity 16 complementary to said male cavity 15 is formed on the part of said envelope 6 intended to come into contact with said base 2.

Il est à noter que la géométrie desdites empreintes mâle 15 et femelle 16 présentées sur les figures 3 et 4 est indiquée à titre d'exemple non limitatif, et que la forme desdites empreintes 15 et 16 est, d'une manière générale, à ajuster, notamment, en fonction des matériaux utilisés et des coûts de réalisation.It should be noted that the geometry of said male and female fingerprints 16 shown in FIGS. 3 and 4 is indicated by way of nonlimiting example, and that the shape of said fingerprints 15 and 16 is, in general, to be adjusted. in particular, depending on the materials used and the costs of production.

Il est également à noter que le principe de la réalisation d'une empreinte mâle 15 et d'une empreinte femelle 16 complémentaire qui vient d'être évoqué peut, dans le mode de réalisation de l'invention présenté par la figure 2B, être également transposé à la réalisation de la liaison entre ladite enveloppe 6 et l'élément de connexion 13 destiné à recevoir le connecteur 12 de connexion électrique de ladite bougie 1 à son dispositif d'alimentation.It should also be noted that the principle of producing a male footprint 15 and a complementary female footprint 16 that has just been mentioned can, in the embodiment of the invention presented in FIG. transposed to the realization of the connection between said envelope 6 and the connecting element 13 for receiving the connector 12 of electrical connection of said candle 1 to its supply device.

Les figures 5, 6A et 6B sont des vues schématiques en coupe, selon l'axe longitudinal Z d'une bougie à plasma radiofréquence 1 selon l'invention, des variantes du second mode de réalisation du dispositif selon l'invention, dans lequel le couple de serrage pour la réalisation de la liaison entre ladite partie essentiellement capacitive C et ladite partie essentiellement inductive I de ladite bougie 1 est transmis par l'âme centrale de ladite partie essentiellement inductive I. Un avantage important de ce mode de transmission est qu'il permet de libérer la totalité de l'espace externe dudit bobinage 5 de ladite partie essentiellement inductive I, et qu'il autorise l'utilisation, pour ledit isolant 7, de matériaux présentant des coefficients de dilatation importants avec la température.FIGS. 5, 6A and 6B are diagrammatic views in section along the longitudinal axis Z of a radiofrequency plasma candle 1 according to the invention, variants of the second embodiment of the device according to the invention, in which the tightening torque for the embodiment of the connection between said substantially capacitive portion C and said essentially inductive portion I of said spark plug 1 is transmitted by the central core of said substantially inductive portion I. An important advantage of this mode of transmission is that it makes it possible to release the all of the outer space of said winding 5 of said substantially inductive portion I, and that it allows the use, for said insulator 7, of materials having significant coefficients of expansion with temperature.

Pour ce mode de transmission dudit couple de serrage, et ainsi que le présente la figure 5, ledit élément central 8, autour duquel est réalisé ledit bobinage 5, est réalisé sous forme d'un mandrin présentant, dans sa partie la plus proche dudit culot 2, une partie élargie 17 de forme et de dimension complémentaires de la forme intérieure du culot 2, de manière à pouvoir assurer le couplage mécanique avec ledit culot 2. Par exemple et de manière non limitative, la forme extérieure de ladite partie élargie 17 peut être sensiblement polygonale, une empreinte complémentaire de ladite forme sensiblement polygonale étant réalisée dans ledit culot 2. Alternativement et de manière non limitative, un élément de liaison (non représenté sur la figure 5) peut également être inséré dans un logement commun audit culot 2 et à ladite partie élargie 17 dudit élément central 8 : cet élément peut, par exemple et de manière non exhaustive, être une clavette insérée sensiblement parallèlement à l'axe longitudinal Z de ladite bougie d'allumage 1 selon l'invention, ou un pion inséré sensiblement perpendiculairement audit axe longitudinal Z de ladite bougie d'allumage 1.For this transmission mode of said tightening torque, and as shown in FIG. 5, said central element 8, around which said winding 5 is made, is produced in the form of a mandrel having, in its part that is closest to said base 2, an enlarged portion 17 of complementary shape and dimension of the inner shape of the base 2, so as to be able to mechanically couple with said base 2. For example and without limitation, the outer shape of said enlarged portion 17 may to be substantially polygonal, a cavity complementary to said substantially polygonal shape being formed in said base 2. Alternatively and in a nonlimiting manner, a connecting element (not shown in FIG. 5) can also be inserted into a housing that is common to said base 2 and to said enlarged portion 17 of said central element 8: this element may, for example and non-exhaustively, be a key inserted substantially parallel to the longitudinal axis Z of said spark plug 1 according to the invention, or a pin inserted substantially perpendicularly to said longitudinal axis Z of said spark plug 1.

Avantageusement, une forme arrondie sera préférée à un angle vif au niveau de l'élargissement 17 dudit élément central 8, de manière à limiter les contraintes mécaniques ainsi que les risques de claquage électromagnétique dans cette zone.Advantageously, a rounded shape will be preferred at a sharp angle at the level of the widening 17 of said central element 8, so as to limit the mechanical stresses and the risks of electromagnetic breakdown in this zone.

Dans ce mode de réalisation, la fonction de blindage précédemment évoquée, et assurée par ladite enveloppe 6, peut être obtenue par différents moyens, illustrés par les figures 6A et 6B.In this embodiment, the shielding function previously mentioned, and provided by said envelope 6, can be obtained by various means, illustrated by FIGS. 6A and 6B.

La figure 6A présente un mode de réalisation dans lequel ladite enveloppe 6 venant entourer ledit isolant 7 placé autour dudit bobinage 5 est une feuille de quelques dizaines de microns d'épaisseur (typiquement et de manière non limitative 75 à 150 µm) réalisée dans un matériau présentant une forte conductivité électrique, ou recouverte, sur sa face au contact dudit isolant 7, d'une couche mince conductrice d'un matériau présentant une forte conductivité électrique (par exemple et de manière non limitative : de l'argent ou du cuivre), de manière à préserver, ainsi qu'il a déjà été décrit précédemment, la qualité électromagnétique de l'ensemble. Dans le cas où ledit isolant 7 présente un fort coefficient de dilatation thermique, ladite enveloppe 6 est préférentiellement enroulée sous une forme polygonale autour dudit isolant 7 : ledit isolant 7 peut ainsi se dilater en convergeant vers une forme extérieure sensiblement cylindrique sans induire de contrainte mécanique supplémentaire sur le périmètre de ladite enveloppe 6.FIG. 6A shows an embodiment in which said envelope 6 surrounding said insulator 7 placed around said winding 5 is a sheet of a few tens of microns thick (typically and not limited to 75 to 150 μm) made of a material having a high electrical conductivity, or covered, on its face in contact with said insulator 7, with a conductive thin layer of a material having a high electrical conductivity (for example and without limitation: silver or copper) , so as to preserve, as already described above, the electromagnetic quality of the assembly. In the case where said insulator 7 has a high coefficient of thermal expansion, said envelope 6 is preferably wound in a polygonal shape around said insulator 7: said insulator 7 can thus expand by converging towards a substantially cylindrical external shape without inducing mechanical stress additional on the perimeter of said envelope 6.

La figure 6B présente un mode de réalisation alternatif, dans lequel ladite enveloppe 6 est remplacée par le dépôt, sur la surface extérieure dudit isolant 7, d'une couche mince conductrice 18 (par exemple et de manière non limitative, une couche de 30 à 50 µm d'épaisseur) d'un matériau présentant une forte conductivité électrique (argent ou cuivre, par exemple et de manière non limitative).FIG. 6B shows an alternative embodiment, in which said envelope 6 is replaced by the deposition, on the outer surface of said insulator 7, of a conductive thin layer 18 (for example and without limitation, a layer of 30 to 50 μm thick) of a material having a high electrical conductivity (silver or copper, for example and without limitation).

Selon une variante du mode de réalisation présenté par la figure 6B et pour des raisons de simplicité de fabrication et de réduction des coûts, ladite couche mince conductrice 18 peut être déposée sur un film polymère lui-même plaqué sous vide sur ledit isolant 7. Avantageusement, dans les deux cas qui viennent d'être évoqués, ladite couche mince conductrice 18 sera protégée de l'extérieur, et, notamment, des phénomènes d'oxydation ou de corrosion pouvant dégrader ses performances électriques, par une couche mince conductrice d'un matériau barrière approprié (par exemple et de manière non limitative : une couche de vernis ou un film polymère).According to a variant of the embodiment shown in FIG. 6B and for reasons of simplicity of manufacture and cost reduction, said thin conductive layer 18 may be deposited on a polymer film itself vacuum-plated on said insulator 7. Advantageously in the two cases just mentioned, said thin conductive layer 18 will be protected from the outside, and, in particular, oxidation or corrosion phenomena that can degrade its electrical performance, by a conductive thin layer of a suitable barrier material (for example and without limitation: a layer of varnish or a polymer film).

Dans tous les modes de réalisation précédemment décrits, la continuité électrique de l'ensemble de ladite bougie 1 selon l'invention est finalisée par ledit élément de connexion 13 destiné au raccordement dudit connecteur 12 à l'alimentation électrique de ladite bougie 1.In all the embodiments previously described, the electrical continuity of the assembly of said spark plug 1 according to the invention is finalized by said connecting element 13 intended for the connection of said connector 12 to the power supply of said spark plug 1.

Avantageusement, ledit élément 13, lié sous une forme rigide, notamment, à ladite enveloppe 6 (par exemple et de manière non limitative, grâce à un des moyens du type de ceux qui viennent d'être décrits pour la liaison de ladite enveloppe 6 avec ledit culot 2), présente une forme adaptée à l'utilisation d'un outil de serrage simple pour la mise en place et le serrage de ladite bougie 1 dans la culasse du moteur.Advantageously, said element 13, bound in a rigid form, in particular, to said envelope 6 (for example and in a nonlimiting manner, thanks to a means of the type of those just described for the connection of said envelope 6 with said base 2), has a shape adapted to the use of a simple clamping tool for the introduction and tightening of said spark plug 1 in the cylinder head of the engine.

Il apparaît ainsi qu'une bougie d'allumage selon l'invention peut être mise en place et retirée de son puits d'accès sans qu'il soit besoin de glisser un outil spécifique autour de ladite bougie : il n'est donc pas nécessaire de ménager, dans ledit puits d'accès à ladite bougie, un espace nécessaire au passage dudit outil spécifique et utilisé uniquement pour les opérations de montage et de démontage de ladite bougie.It thus appears that a spark plug according to the invention can be put in place and removed from its access well without the need to slide a specific tool around said candle: it is therefore not necessary to provide, in said access shaft to said candle, a space necessary for the passage of said specific tool and used only for the assembly and disassembly operations of said candle.

Il est à noter que le principe de liaison rigide à la fois mécanique et électrique entre les deux parties d'une bougie d'allumage (bougie proprement dite et sa bobine), ici décrit dans son application à une bougie à plasma radiofréquence, et préférentiellement destiné à ce type de bougie, peut être transposé à tout type de bougie conventionnelle.It should be noted that the principle of rigid connection both mechanical and electrical between the two parts of a spark plug (candle itself and its coil), here described in its application to a radiofrequency plasma candle, and preferentially intended for this type of candle, can be transposed to any type of conventional candle.

Claims (13)

  1. Spark plug (1) of an internal combustion engine of a motor vehicle, whose general shape is substantially cylindrical, of the type comprising mainly an essentially capacitive portion (C), closest to the cylinder head of the said engine and comprising a shell (2) surrounding a central electrode (3), that is substantially cylindrical and playing the role of a high voltage electrode, and an essentially inductive portion (I), furthest from the said cylinder head of the said engine, the said essentially capacitive portion (C) and the said essentially inductive portion (I) being connected in series to form an LC resonator and comprising a common longitudinal axis substantially indistinguishable from the longitudinal axis (Z) of the said spark plug (1), characterized in that:
    - the said essentially inductive portion (I) is surrounded by a casing (6) whose dimensions and materials are, in particular, appropriate for the production of an electromagnetic shielding of the said essentially inductive portion (I),
    - the said essentially capacitive portion (C) and the said essentially inductive portion (I) of the said spark plug (1) are connected together mechanically and electrically by a single rigid device, making it possible to transmit a torque from the said essentially inductive portion (I) to the said essentially capacitive portion (C).
  2. Spark plug (1) according to Claim 1, characterized in that the said transmission of the said torque is carried out via the perimeter of the said essentially inductive portion (I) of the said spark plug (1).
  3. Spark plug (1) according to Claim 2, in which the said casing (6) is metallic, characterized in that the said casing (6) and the said shell (2) form a single part.
  4. Spark plug (1) according to Claim 2, in which the said casing (6) is a thin metal sheet, characterized in that the said casing (6) is welded to the said shell (2).
  5. Spark plug (1) according to Claim 3 or 4, characterized in that the internal face of the said casing (6) is coated with a thin conductive layer made of a highly electrically conductive material.
  6. Spark plug (1) according to Claim 2, characterized in that the said casing (6) is a sleeve made of a polymer, and in that the outer face of the said casing (6) is coated with a thin conductive layer made of a highly electrically conductive material.
  7. Spark plug (1) according to Claim 6, characterized in that the portion of the said shell (2) designed to be in contact with the said casing (6) comprises a shape (16) matching the shape (15) made on the section of the casing (6), and in that the thin conductive layer extends up to the shape made on the section of the casing (6).
  8. Spark plug (1) according to Claim 1, in which the said inductive portion (I) comprises, in particular, a coil (5) made around a central element (8) and surrounded by an insulating sleeve (7), the said insulating sleeve (7) itself being surrounded by the said casing (6), characterized in that the said transmission of the said torque is performed via the said central element (8).
  9. Spark plug (1) according to Claim 8, characterized in that the said central element (8) comprises, at its end closest to the said shell (2), an enlarged portion (17) with a form matching the form of the internal face of the shell in order to provide a rigid mechanical connection with the said shell (2) .
  10. Spark plug (1) according to Claim 8, characterized in that the said enlarged portion (17) of the said central element (8) and the said shell (2) comprise a common housing designed to receive an element providing the connection between the said enlarged portion (17) and the said shell (2).
  11. Spark plug (1) according to any one of Claims 8 to 10, in which the said casing (6) is a sheet of a few tens of microns thick of a conductive material, characterized in that the said casing (6) is rolled in a polygonal form around the said insulating sleeve (7).
  12. Spark plug (1) according to any one of Claims 8 to 11, characterized in that the said casing (6) is coated, on its internal face, with a thin conductive layer made of a highly electrically conductive material.
  13. Spark plug (1) according to any one of Claims 8 to 12, characterized in that the outer face of the said insulating sleeve (7) is coated with a thin conductive layer (18) of a highly electrically conductive material.
EP05300966A 2004-11-29 2005-11-25 New mounting method of a spark plug and bobbin assembly using a transmission of the tightning couple through the bobbin housing Not-in-force EP1662626B1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR0452790A FR2878658A1 (en) 2004-11-29 2004-11-29 NEW METHOD FOR MOUNTING A CANDLE AND SPOOL ASSEMBLY USING A TORQUE TRANSMISSION BY THE SPOOL BODY

Publications (2)

Publication Number Publication Date
EP1662626A1 EP1662626A1 (en) 2006-05-31
EP1662626B1 true EP1662626B1 (en) 2008-01-16

Family

ID=34953404

Family Applications (1)

Application Number Title Priority Date Filing Date
EP05300966A Not-in-force EP1662626B1 (en) 2004-11-29 2005-11-25 New mounting method of a spark plug and bobbin assembly using a transmission of the tightning couple through the bobbin housing

Country Status (5)

Country Link
EP (1) EP1662626B1 (en)
AT (1) ATE384351T1 (en)
DE (1) DE602005004362T2 (en)
ES (1) ES2299983T3 (en)
FR (1) FR2878658A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103726972A (en) * 2012-10-12 2014-04-16 博格华纳贝鲁系统股份有限公司 Corona igniter with gas-tight hf plug connector

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2907269B1 (en) * 2006-10-17 2009-01-30 Renault Sas DEVICE FOR GENERATING RADIOFREQUENCY PLASMA.
PL2058909T3 (en) * 2007-11-08 2012-09-28 Delphi Tech Inc Resonant assembly
WO2010043542A1 (en) * 2008-10-13 2010-04-22 Delphi Technologies, Inc. Arrangement for spark plug connection with ignition coil
EP2456027A1 (en) * 2010-11-23 2012-05-23 Delphi Technologies, Inc. Encapsulation of a high frequency resonator for the ignition system of an internal combustion engine
FR2995460B1 (en) * 2012-09-12 2014-08-29 Renault Sa "RADIOFREQUENCY SPARK TYPE IGNITION SPARK PLUG WITH INTEGRATED BREAK"
DE102013100925A1 (en) 2013-01-30 2014-07-31 Borgwarner Beru Systems Gmbh Coil and corona ignition device with such a coil
DE102014102230B4 (en) 2013-04-22 2019-07-11 Borgwarner Ludwigsburg Gmbh Process for producing a corona ignition device

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19723784C1 (en) * 1997-06-06 1998-08-20 Daimler Benz Ag Circuit for ignition system of IC engine supplying high voltage to spark plug electrodes
DE19829443A1 (en) * 1998-07-01 2000-01-05 Bayerische Motoren Werke Ag spark plug
US6703770B2 (en) * 2001-04-12 2004-03-09 Akira Suzuki Spark plug attachment structure and spark plug therefor
JP3849649B2 (en) * 2002-04-01 2006-11-22 株式会社デンソー Ignition device for internal combustion engine and manufacturing method thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103726972A (en) * 2012-10-12 2014-04-16 博格华纳贝鲁系统股份有限公司 Corona igniter with gas-tight hf plug connector
CN103726972B (en) * 2012-10-12 2017-06-30 博格华纳贝鲁系统股份有限公司 Corona ignition device with airtight high frequency plug-in connector

Also Published As

Publication number Publication date
ATE384351T1 (en) 2008-02-15
ES2299983T3 (en) 2008-06-01
DE602005004362T2 (en) 2009-01-15
EP1662626A1 (en) 2006-05-31
FR2878658A1 (en) 2006-06-02
DE602005004362D1 (en) 2008-03-06

Similar Documents

Publication Publication Date Title
EP1662626B1 (en) New mounting method of a spark plug and bobbin assembly using a transmission of the tightning couple through the bobbin housing
EP1949514B1 (en) Sparkplug for an internal combustion engine
EP1920510B1 (en) Plasma spark plug for an internal combustion engine
EP0713006B1 (en) Ignition part for internal combustion engines and method of manufacturing it
FR2884063A1 (en) IGNITION CANDLE FOR AN INTERNAL COMBUSTION ENGINE
FR2831243A1 (en) Preheating plug for Diesel internal combustion engine has liner with heating element at one end and connector cap at other
EP1897193B1 (en) Spark plug for an internal combustion engine
EP2614562A1 (en) Sparkplug for an internal combustion engine
WO2011085959A1 (en) Heater plug having a metal lug
WO2010026315A1 (en) Device including a pressure sensor for measuring pressures in an internal combustion engine, and body for such a device
EP2210079B1 (en) Spark ignition device with in-built combustion sensor
FR2916582A1 (en) SCREW, IN PARTICULAR ELECTRIC STARTER TERMINAL, AND METHOD OF MAKING SAME
EP1202411B1 (en) Gliding discharge spark plug with radial spark
EP1594201A1 (en) Multiple spark surface discharge spark plug
EP1758219B1 (en) Spark plug for internal combustion engine
EP2519812A2 (en) Ignition and pressure measurement device of an internal combustion engine
EP2419977B1 (en) High voltage resonator-amplifier with an optimized structure for radiofrequency ignition system
FR2785335A1 (en) IGNITION DEVICE FOR INTERNAL COMBUSTION ENGINE
FR2762442A1 (en) Coil feed for thermal motor spark plug
FR2855317A1 (en) Ignition coil manufacturing method for internal combustion engines spark plug, involves molding secondary coil and carcass assembly, in dielectric material assuring secondary coils impregnation and primary carcass formation
WO2013150077A1 (en) Method of metallizing a connection pad of a multilayer electrical component
FR2899393A1 (en) High voltage central electrode for radiofrequency plasma generation spark plug, has stem connected to plug`s coil, where electrode is made of nickel and coil has one end turn connected to inner end of electrode by connection system
FR2861509A1 (en) SURFACE SPARKING IGNITION CANDLE WITH DIRECTED SPARK.
WO2017032930A1 (en) Electrical connector of an electromagnetic actuator for a valve
FR2982711A1 (en) Spark plug for use on combustion chamber of internal combustion engine of vehicle, has insulator extending longitudinally from stopper to vicinity of free end of electrode, and coil fixed on external part of internal hollow wall

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL BA HR MK YU

17P Request for examination filed

Effective date: 20061116

AKX Designation fees paid

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR

17Q First examination report despatched

Effective date: 20070119

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

Free format text: NOT ENGLISH

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

Free format text: LANGUAGE OF EP DOCUMENT: FRENCH

REF Corresponds to:

Ref document number: 602005004362

Country of ref document: DE

Date of ref document: 20080306

Kind code of ref document: P

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)

Effective date: 20080413

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080116

REG Reference to a national code

Ref country code: ES

Ref legal event code: FG2A

Ref document number: 2299983

Country of ref document: ES

Kind code of ref document: T3

NLV1 Nl: lapsed or annulled due to failure to fulfill the requirements of art. 29p and 29m of the patents act
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080116

Ref country code: LT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080116

Ref country code: IS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080516

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080116

Ref country code: BG

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080416

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: PL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080116

Ref country code: SI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080116

Ref country code: LV

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080116

Ref country code: PT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080616

REG Reference to a national code

Ref country code: IE

Ref legal event code: FD4D

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: CZ

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080116

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080116

Ref country code: SE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080416

Ref country code: IE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080116

Ref country code: SK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080116

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: RO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080116

26N No opposition filed

Effective date: 20081017

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: EE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080116

BERE Be: lapsed

Owner name: RENAULT

Effective date: 20081130

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MC

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20081130

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: CY

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080116

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20081130

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20081125

Ref country code: HU

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080717

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: TR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080116

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20080417

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20091130

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20091130

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 11

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 12

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 13

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20211118

Year of fee payment: 17

Ref country code: GB

Payment date: 20211119

Year of fee payment: 17

Ref country code: FR

Payment date: 20211122

Year of fee payment: 17

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: IT

Payment date: 20211119

Year of fee payment: 17

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: ES

Payment date: 20220121

Year of fee payment: 17

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 602005004362

Country of ref document: DE

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20221125

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20221125

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20221125

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20230601

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20221130

REG Reference to a national code

Ref country code: ES

Ref legal event code: FD2A

Effective date: 20240102

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20221126

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20221126