EP0050552A1 - Spark plug - Google Patents

Spark plug Download PDF

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Publication number
EP0050552A1
EP0050552A1 EP81401566A EP81401566A EP0050552A1 EP 0050552 A1 EP0050552 A1 EP 0050552A1 EP 81401566 A EP81401566 A EP 81401566A EP 81401566 A EP81401566 A EP 81401566A EP 0050552 A1 EP0050552 A1 EP 0050552A1
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EP
European Patent Office
Prior art keywords
base
solid support
electrode
insulator
spout
Prior art date
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Granted
Application number
EP81401566A
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German (de)
French (fr)
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EP0050552B1 (en
Inventor
Michel Georges Pierre Matesco
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Eyquem Dite Ste
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Eyquem Dite Ste
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Priority to US06/320,799 priority Critical patent/US4527260A/en
Publication of EP0050552A1 publication Critical patent/EP0050552A1/en
Application granted granted Critical
Publication of EP0050552B1 publication Critical patent/EP0050552B1/en
Expired legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T13/00—Sparking plugs
    • H01T13/02—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
    • H01T13/02—Details
    • H01T13/16—Means for dissipating heat
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T13/00—Sparking plugs
    • H01T13/20—Sparking plugs characterised by features of the electrodes or insulation
    • H01T13/32—Sparking plugs characterised by features of the electrodes or insulation characterised by features of the earthed electrode

Definitions

  • the present invention relates to spark plugs for spark-ignition internal combustion engines.
  • Spark plugs currently used include a threaded base by means of which the spark plug is screwed into a hole in the cylinder head of an engine, a ceramic body fixed to the base and inside which is disposed a central electrode. isolated from the base, and a ground electrode which is attached to the base, the central electrode being connected to a terminal or opposite external terminal screw used to make the external connection.
  • the service life of spark plugs currently used is mainly limited by the degradation and fouling of the electrodes and the insulator spout, and this degradation has been found, which in most chamber configurations combustion conditions, mainly affects the mass electrode, is linked to various factors such as temperature, valve arrangement, fuel composition, engine setting and others while fouling occurs mainly at low engine speeds. engine and low temperature.
  • the temperature of the central electrode and of the spout of the insulator is insufficient to cause pyrolysis of carbon deposits, the accumulation of which leads to misfires and consequently a faulty engine operation.
  • pre-ignition the well-known phenomenon of early ignition known as "pre-ignition" which is destructive to the engine.
  • the spout of the insulator of the central electrode protrudes beyond the edge of the base, thus exposing the latter and the central electrode to the flame front of the combustion chamber.
  • the pyrolysis temperature of the deposits is thus easily reached. carbonaceous. However, at the level of the insulator spout, the average operating temperature is high, thus favoring the corrosion of the active part.
  • the invention proposes to remedy these various drawbacks by producing a spark plug in which the nozzle of the insulator of the central electrode is kept in the appropriate temperature range and the temperature of the ground electrode is notably lowered in service. and having excellent properties of self-cleaning by pyrolysis, while allowing inexpensive manufacture.
  • the subject of the invention is therefore a spark plug for spark ignition internal combustion engine characterized in that it comprises means for removing both the heat from the ground electrode, from the central electrode and the end of the spout of the insulator thereof, this end protruding into the combustion chamber in which it is partially exposed to the flame front and is partially masked by said means, these constituting a support for the ground electrode.
  • spark plug of the prior art which comprises a body 1 having a threaded base 2 screwed into the cylinder head 3 of an engine conventionally cooled by means 4 of water circulation.
  • An insulating body 5 surrounds the central electrode and fixes it in the body 1. The end of the central electrode projects from the end 8 of the spout 7 of the insulator 5.
  • a ground electrode 9 is fixed on the edge of the base 2 and extends radially in front of the end 6 of the central electrode in a known manner.
  • the base 2 has internally a shoulder 10 for centering and holding the insulating body 5.
  • the end 8 of the spout 7 extends, axially, slightly behind the edge of the base 2.
  • the maximum temperature of the cooling water being 100 ° C.
  • the temperature of the part of the cylinder head in contact with the base is approximately 200 ° C.
  • the active part of the candle made up by the end 8 of the spout 7 of the insulator, the end 6 of the central electrode and the ground electrode, present in service at full speed, a temperature of the order of 800 to 850 ° C.
  • This dissipation is so effective that the spout of the insulation has a relatively low temperature at low engine operating speeds and well below 500 ° C at idle.
  • Fig. 2 is a view similar to that of FIG. 1 showing a candle of another known type which differs from the candle described above in that the spout 7 of the insulator extends axially beyond the edge of the base 2, so that part of its end 8 projects into the combustion chamber, where it is thus exposed to the flame front of the combustion.
  • the heat from the main part of the spout 7 located inside the base 2 is removed, as in the previous example partly by conduction with the body 1 and for a weaker part by radiation as indicated by the arrows in the base 2 .
  • the active part that is to say the end 8 of the spout and that of the central electrode 6 do not foul, being maintained at a very high temperature by combustion, which burns deposits.
  • This type of candle has mediocre properties. corrosion resistance.
  • Fig. 3 shows a candle according to the invention which comprises means for dissipating both the heat from the nozzle of the insulator and from the end 6 of the electrode over the entire length of the latter by radiation, as well as the heat of the ground electrode, by conduction, while the end 8 of the spout of the insulator and that 6 of the central electrode are partially exposed to the flame front of the combustion chamber, projecting therein.
  • These means consist of a massive appendage 12 which is integral with the edge of the base 2 and extends the latter by extending axially at least to the level of the end 6 of the central electrode, constituting both a solid cold support for the ground electrode 9 and a cold wall partially surrounding the central electrode and the spout of the insulator.
  • the appendix to the solid support 12 extends axially from an arc of the periphery of the edge of the end of the base 2, which is between Ge and 120 degrees and is preferably equal to a quarter of the circumference .
  • the ground electrode 9 consisting of a small rod made of conventional nickel alloy used for the spark plug ground electrodes is fixed by one end to the internal face of the support 12 in the vicinity of the end of the central electrode 4 at a desired distance from it, about 6/10 mm.
  • the support 12 can either be integral with the edge of the base during manufacture, by machining, cold stamping or other suitable technique, or be formed separately and fixed to the edge of the base, for example by welding.
  • support 12 is in operation approximately. the same temperature as the base, so that its mass and that of the cold base act like a heat sink for the mass electrode which it carries whose volume is reduced compared to that of. ground electrode of a conventional candle thanks to this arrangement.
  • the support 12 constitutes at the same time a cold wall which extends opposite the nozzle of the insulator and the central electrode over a sufficient part of their periphery to absorb and dissipate the calories emitted by radiation by the nozzle and the electrode.
  • the support 12 has two lateral edges 13 which are approximately vertical and perpendicular to the end edge of the base 2.
  • the support 12 has two side edges rails 14 inclined so that in this embodiment this support 12 has in elevation the shape of an isosceles trapezium as shown in FIG. 7.
  • ground electrode 9 does not extend beyond the end of the support 12 in the axial direction, the location of its fixing being indicated in lines interrupted.
  • the mass of the electrode 9 is much less than that of the support 12 and consequently the latter constitutes a good heat sink making it possible to lower the temperature of the mass electrode in service.
  • the Applicant has found that the spark plugs as described above do not disturb the mixture in the combustion chamber and that their electrodes are well exposed to the flame front and consequently are well cleaned by pyrolysis. In addition, the temperature of the active parts is kept within the optimum range.
  • the latter can be pierced with a hole 40 which passes through it, just below the electrode 9, as shown in Fig. 7, allowing even better sweeping of the end 6 of the central electrode by the flames, without hampering the transfer of calories by radiation, this radiation occurring mainly at the level of the nozzle of the insulator.
  • the invention allows not only a lowering of the temperature of the electrodes in service., But also self-cleaning properties by pyrolysis with a minimum of manufacturing costs, thus achieving a candle whose lifespan is very significantly extended compared to conventional candles.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Spark Plugs (AREA)
  • Ignition Installations For Internal Combustion Engines (AREA)

Abstract

Cette bougie d'allumage par étincelles pour moteur à combustion interne à allumage commandé comprend des moyens (12) pour évacuer à la fois la chaleur de l'électrode de masse (9), de l'électrode centrale (6) et de l'extrémité (8) du bec de l'isolant (7) de celle-ci, cette extrémité (8) étant en saillie dans la chambre de combustion dans laquelle elle est partiellement exposée au front de flammes et en est partiellement masquée par lesdits moyens (12), ceux-ci constituant un support massif pour l'électrode de masse (9).This spark ignition plug for an internal combustion engine with spark ignition comprises means (12) for removing the heat from the mass electrode (9), the central electrode (6) and the end (8) of the nozzle of the insulator (7) thereof, this end (8) projecting into the combustion chamber in which it is partially exposed to the flame front and is partially masked by said means ( 12), these constituting a solid support for the ground electrode (9).

Description

La présente invention est relative aux bougies d'allumage par étincelles pour moteurs à combustion interne à allumage commandé.The present invention relates to spark plugs for spark-ignition internal combustion engines.

L'une des préoccupations des fabricants de bougies consiste à essayer d'accroître la durée de service des bougies tout en assurant l'allumage dans les meilleures conditions.One of the concerns of candle manufacturers is to try to increase the life of the candles while ensuring the ignition in the best conditions.

Les bougies d'allumage par étincelles utilisées actuellement comprennent un culot fileté au moyen duquel la bougie est vissée dans un trou de la culasse d'un moteur, un corps en céramique fixé sur le culot et à l'intérieur duquel est disposée une électrode centrale isolée du culot, et une électrode de masse qui est rapportée sur le culot, l'électrode centrale étant reliée à une borne ou vis terminale externe opposée utilisée pour réaliser la connexion extérieure.Spark plugs currently used include a threaded base by means of which the spark plug is screwed into a hole in the cylinder head of an engine, a ceramic body fixed to the base and inside which is disposed a central electrode. isolated from the base, and a ground electrode which is attached to the base, the central electrode being connected to a terminal or opposite external terminal screw used to make the external connection.

La durée de vie des bougies d'allumage par étincelles utilisées actuellement est principalement limitée par la dégradation et l'encrassement des électrodes et du bec de l'isolant et l'on a constaté que cette dégradation, qui dans la plupart des configurations des chambres de combustion actuelles, affecte essentiellement l'électrode de masse, est liée à différents facteurs tels que la température, la disposition des soupapes, la composition du carburant, le réglage du moteur et autres tandis que l'encrassement se produit principalement à bas régime du moteur et à basse température.The service life of spark plugs currently used is mainly limited by the degradation and fouling of the electrodes and the insulator spout, and this degradation has been found, which in most chamber configurations combustion conditions, mainly affects the mass electrode, is linked to various factors such as temperature, valve arrangement, fuel composition, engine setting and others while fouling occurs mainly at low engine speeds. engine and low temperature.

En plus, de ces facteurs habituels d'usure des électrodes, il convient d'ajouter d'une part la présence d'additifs au plomb dans les carburants utilisés-actuellement, qui provoquent un encrassement et une corrosion sévère des électrodes et du bec d'isolant ainsi qu'une élévation de leur température, et d'autre part l'appauvrissement . du mélange dans un but d'économie, qui a également pour résultat une augmentation de la température au niveau des électrodes, qui à son tour favorise la corrosion.In addition to these usual factors of electrode wear, it is advisable to add, on the one hand, the presence of lead additives in the fuels currently used, which cause fouling and severe corrosion of the electrodes and the spout. 'insulation and a rise in their temperature, and secondly the depletion. mixing for the sake of economy, which also result in an increase in temperature at the electrodes, which in turn promotes corrosion.

A bas régime du moteur, par exemple en circulation urbaine, la température de l'électrode centrale et du bec de l'isolant est insuffisante pour provoquer la pyrolyse des dépôts carbonés dont l'accumulation conduit à des ratés d'allumage et par conséquent un fonctionnement défectueux du moteur.At low engine speed, for example in city traffic, the temperature of the central electrode and of the spout of the insulator is insufficient to cause pyrolysis of carbon deposits, the accumulation of which leads to misfires and consequently a faulty engine operation.

A régimé élevé du moteur, si la température est trop élevée, il en résulte le phénomène bien connu d'allumage anticipé dit " pré-allumage" qui est destructif pour le moteur.At high engine speed, if the temperature is too high, this results in the well-known phenomenon of early ignition known as "pre-ignition" which is destructive to the engine.

On a constaté que la température minimale au-dessous de laquelle se produit l'encrassement est de 500°C, tandis que la température maximale au-dessus de laquelle se. produit l'allumage anticipé est de 800 à 850°.It has been found that the minimum temperature below which fouling occurs is 500 ° C, while the maximum temperature above which occurs. produces the early ignition is 800 to 850 °.

En conséquence, pour augmenter la durée de vie d'une bougie d'allumage tout en assurant celui-ci de manière à obtenir le meilleur rendement du moteur, il est essentiel d'une part d'assurer une bonne dissipation de la chaleur des électrodes lors du fonctionnement, et d'autre part de réaliser un agencement approprié pour éviter l'encrassement des électrodes et du bec de l'isolant, c'est-à-dire permettant d'obtenir un auto- nettoyage par effet de pyrolyse en maintenant la température des électrodes dans une plage de 500 à 800°C.Consequently, to increase the service life of a spark plug while ensuring it so as to obtain the best efficiency from the engine, it is essential on the one hand to ensure good dissipation of the heat from the electrodes during operation, and on the other hand to make an appropriate arrangement to avoid fouling of the electrodes and the spout of the insulator, that is to say allowing self-cleaning to be obtained by pyrolysis effect while maintaining the temperature of the electrodes in a range of 500 to 800 ° C.

Différentes tentatives ont été faites jusqu'à présent afin d'atteindre ces résultats, mais les diverses solutions envisagées n'ont pas permis d'atteindre ces deux buts de façon tout à fait satisfaisante.Various attempts have been made so far in order to achieve these results, but the various solutions envisaged have not made it possible to achieve these two goals in a completely satisfactory manner.

La plupart des bougies utilisées jusqu'à une époque récente comportaient un culot dont le bord s'étendait uniformément au-delà du bec de l'isolant de l'électrode centrale et parfois même, dans certains types de bougie, au-delà de l'extrémité de cette_électrode.Most candles used until recent times had a base, the edge of which extended evenly beyond the spout of the insulator of the central electrode and sometimes even, in certain types of spark plug, beyond the end of this electrode.

Dans ces bougies on obtient une température relativement peu élevée du bec de l'isolant à faible régime... Ceci présente l'inconvénient d'un encrassement rapide et important.In these candles a relatively low temperature of the nozzle of the insulator is obtained at low speed ... This has the disadvantage of rapid and significant fouling.

Dans un autre type de bougie, qui-tend actuellement à se généraliser, le bec de l'isolant de l'électrode centrale fait saillie au-delà du bord du culot, exposant ainsi celui-ci et l'électrode centrale au front de flammes de la chambre de combustion.In another type of candle, which is currently tending to generalize, the spout of the insulator of the central electrode protrudes beyond the edge of the base, thus exposing the latter and the central electrode to the flame front of the combustion chamber.

On atteint ainsi facilement la température de pyrolyse des dépôts. carbonés. Toutefois, au niveau du bec de l'isolant, la température moyenne de fonctionnement est élevée favorisant ainsi la.corrosion de la partie active.The pyrolysis temperature of the deposits is thus easily reached. carbonaceous. However, at the level of the insulator spout, the average operating temperature is high, thus favoring the corrosion of the active part.

En ce qui concerne le refroidissement de l'électrode centrale, celui-ci est à peu près satisfaisant dans les bougies dont le culot s'étend au-delà du bec de l'isolant.As regards the cooling of the central electrode, this is almost satisfactory in the spark plugs, the base of which extends beyond the nozzle of the insulator.

Dans les bougies dans lesquelles le bec de l'isolant s'étend au-delà du culot, l'électrode de masse, nécessairement plus longue est mal refroidie et se corrode très rapidement.In candles in which the spout of the insulator extends beyond the base, the ground electrode, which is necessarily longer, is poorly cooled and corrodes very quickly.

On a décrit au brevet américain n° 1.441.444 une bougie d'allumage comportant un culot s'étendant au-delà du bec de l'isolant et présentant en outre deux petites, oreilles entre lesquelles s'étend une électrode diamétrale dont la chaleur, sufisamment élevée pour assurer la carbonisation des dépôts, est partiel- lemnt évacuée par les oreilles du culot.American patent No. 1,441,444 describes a spark plug comprising a base extending beyond the spout of the insulator and also having two small ears between which a diametral electrode extends, the heat of which , sufficiently high to ensure the charring of the deposits, is partially evacuated by the ears of the pellet.

Dans une telle bougie, cependant, le bec de l'isolant et l'électrode centrale sont complètement masqués par le culot, par ses oreilles et l'électrode de masse de forte section et sont de ce fait sujets à un encrassement considérable qui est en outre pratiquement impossible à éliminer par nettoyage de la bougie lorsque celle-ci est retirée de la culasse du moteur.In such a candle, however, the spout of the insulator and the central electrode are completely masked by the base, by its ears and the mass electrode of large section and are therefore subject to considerable fouling which is also practically impossible to remove by cleaning the spark plug when it is removed from the cylinder head of the engine.

L'invention se propose de remédier à ces différents inconvénients en réalisant une bougie dans laquelle le bec de l'isolant de l'électrode centrale est maintenue dans la plage de température appropriée et la température de l'électrode de masse est notablement abaissée en service et présentant d'excellentes propriétés d'auto- nettoyage par,pyrolyse, tout en permettant une fabrication peu coûteuse.The invention proposes to remedy these various drawbacks by producing a spark plug in which the nozzle of the insulator of the central electrode is kept in the appropriate temperature range and the temperature of the ground electrode is notably lowered in service. and having excellent properties of self-cleaning by pyrolysis, while allowing inexpensive manufacture.

L'invention a pour objet à cet effet une bougie d'allumage par étincelles pour moteur à combustion interne à allumage commandé caractérisé en ce qu'elle comprend des moyens pour évacuer à la fois la chaleur de l'électrode de masse, de l'électrode centrale et de l'extrémité du bec de l'isolant de celle-ci, cette extrémité étant en saillie dans la chambre de combustion dans laquelle elle est partiellement exposée au front de flammes et en est partiellement masquée par lesdits moyens, ceux-ci constituant un support pour l'électrode de masse.The subject of the invention is therefore a spark plug for spark ignition internal combustion engine characterized in that it comprises means for removing both the heat from the ground electrode, from the central electrode and the end of the spout of the insulator thereof, this end protruding into the combustion chamber in which it is partially exposed to the flame front and is partially masked by said means, these constituting a support for the ground electrode.

D'autres caractéristiques et avantages de l'invention apparaîtront au cours de la description qui va suivre faite en se référant au dessin annexé donné uniquement à titre d'exemple et dans lequel :

  • - la Fig. 1 est une vue partielle en coupe d'une bougie d'allumage par étincelles de la technique antérieure;
  • - la Fig. 2 est une vue analogue à celle de la Fig. 1 d'un autre type de bougie connu;
  • - la Fig. 3 est une vue analogue d'un mode de réalisation d'une bougie suivant l'invention;
  • - la Fig. 4 est une vue schématique partielle montrant en élévation latérale l'extrémité du culot d'une bougie suivant l'invention;
  • - la Fig. 5 est une vue à 90° par rapport à celle de la Fig.4 dans le sens de la flèche 1, montrant la forme de la saillie du culot sur laquelle est fixée l'électrode de masse;
  • - les Fig. 6 et 7 sont des vues analogues à celles des Fig. 4 et 5, respectivement d'un second mode de réalisation.
Other characteristics and advantages of the invention will become apparent during the description which follows, made with reference to the appended drawing given solely by way of example and in which:
  • - Fig. 1 is a partial sectional view of a spark plug of the prior art;
  • - Fig. 2 is a view similar to that of FIG. 1 of another known type of candle;
  • - Fig. 3 is a similar view of an embodiment of a candle according to the invention;
  • - Fig. 4 is a partial schematic view showing in side elevation the end of the base of a candle according to the invention;
  • - Fig. 5 is a view at 90 ° with respect to that of FIG. 4 in the direction of arrow 1, showing the shape of the projection of the base on which the ground electrode is fixed;
  • - Figs. 6 and 7 are views similar to those of FIGS. 4 and 5, respectively of a second embodiment.

Dans les différentes figures du dessin, les parties analogues sont désignées par les mêmes références.In the various figures of the drawing, the analogous parts are designated by the same references.

On a représenté en coupe à la Fig. 1 une bougie d'allumage par étincelles de la technique antérieure qui comprend un corps 1 ayant un culot fileté 2 vissé dans la culasse 3 d'un moteur refroidie de façon classique par des moyens 4 de circulation d'eau.There is shown in section in FIG. 1 a spark plug of the prior art which comprises a body 1 having a threaded base 2 screwed into the cylinder head 3 of an engine conventionally cooled by means 4 of water circulation.

Un corps isolant 5 entoure l'électrode centrale et la fixe dans le corps 1. L'extrémité de l'électrode centrale fait saillie de l'extrémité 8 du bec 7 de l'isolant 5.An insulating body 5 surrounds the central electrode and fixes it in the body 1. The end of the central electrode projects from the end 8 of the spout 7 of the insulator 5.

Une électrode de masse 9 est fixée sur le bord du culot 2 et s'étend radialement devant l'extrémité 6 de l'électrode centrale de façon connue.A ground electrode 9 is fixed on the edge of the base 2 and extends radially in front of the end 6 of the central electrode in a known manner.

Le culot 2 comporte intérieurement un épaulement 10 de centrage et de maintien du corps isolant 5.The base 2 has internally a shoulder 10 for centering and holding the insulating body 5.

Au-delà de cet épaulement, la surface interne du culot 2 de diamètre plus grand délimite avec le bec 7 un espace annulaire 11.Beyond this shoulder, the internal surface of the base 2 of larger diameter defines with the spout 7 an annular space 11.

L'extrémité 8 du bec 7 s'étend, axialement, légèrement en retrait par rapport au bord du culot 2.The end 8 of the spout 7 extends, axially, slightly behind the edge of the base 2.

En service, la température maximum de l'eau de refroidissement étant de 100°C, la température de la partie de la culasse en contact avec le culot est d'environ 200°C.In operation, the maximum temperature of the cooling water being 100 ° C., the temperature of the part of the cylinder head in contact with the base is approximately 200 ° C.

La partie active de la bougie constituée par l'extrémité 8 du bec 7 de l'isolant, l'extrémité 6 de l'électrode centrale et l'électrode de masse, présente en service à plein régime une température de l'ordre de 800 à 850°C.The active part of the candle made up by the end 8 of the spout 7 of the insulator, the end 6 of the central electrode and the ground electrode, present in service at full speed, a temperature of the order of 800 to 850 ° C.

La Demanderesse a constaté que dans une telle bougie la chaleur du bec 7 de l'électrode centrale 6 est dissipée d'une part par conduction au niveau du corps 5 et d'autre part par rayonnement comme indiqué par les flèches dans la paroi froide du culot dont la masse est maintenue à une température considérablement inférieure grâce à son contact avec la culasse.The Applicant has found that in such a candle the heat from the spout 7 of the central electrode 6 is dissipated on the one hand by conduction at the level of the body 5 and on the other hand by radiation as indicated by the arrows in the cold wall of the base whose mass is maintained at a considerably lower temperature thanks to its contact with the cylinder head.

Cette dissipation est si efficace que le bec de l'isolant présente une température relativement -peu élevée aux faibles régimes de fonctionnemnt du moteur et bien inférieure à 500°C au ralenti.This dissipation is so effective that the spout of the insulation has a relatively low temperature at low engine operating speeds and well below 500 ° C at idle.

En conséquence une telle bougie s'encrasse relativement rapidement et les dépôts carbonés s'accumulent dans l'espace annulaire entourant le bec 7, provoquant des défauts d'allumage par court-circuit.Consequently, such a spark plug fouls relatively quickly and carbon deposits accumulate in the annular space surrounding the spout 7, causing ignition faults by short circuit.

La Fig. 2 est une vue analogue à celle de la Fig. 1 montrant une bougie d'un autre type connu qui diffère de la bougie décrite ci-dessus en ce que le bec 7 de l'isolant s'étend axialement au-delà du bord du culot 2, de telle sorte qu'une partie de son extrémité 8 fait saillie dans la chambre de combustion, où elle se trouve ainsi exposée au front de flammes de la combustion.Fig. 2 is a view similar to that of FIG. 1 showing a candle of another known type which differs from the candle described above in that the spout 7 of the insulator extends axially beyond the edge of the base 2, so that part of its end 8 projects into the combustion chamber, where it is thus exposed to the flame front of the combustion.

La chaleur de la partie principale du bec 7 située â_l'intérieur du culot 2 est évacuée, comme dans l'exemple précédent en partie par conduction avec le corps 1 et pour une partie plus faible par rayonnement comme indiqué par les flèches dans le culot 2.The heat from the main part of the spout 7 located inside the base 2 is removed, as in the previous example partly by conduction with the body 1 and for a weaker part by radiation as indicated by the arrows in the base 2 .

La partie active, c'est-à-dire l'extrémité 8 du bec et celle de l'électrode centrale 6 ne s'encrassent pas, étant maintenues à une température très élevée par la combustion, qui brûle les dépôts.The active part, that is to say the end 8 of the spout and that of the central electrode 6 do not foul, being maintained at a very high temperature by combustion, which burns deposits.

Par contre la température de fonctionnement est trop élevée du fait que les calories de l'extrémité 8 et de l'électrode 6 ne peuvent se dissiper par rayonnement, aucune partie froide ne se trouvant à proximité.Against by the operating temperature is too high because the calories from the end 8 and the electrode 6 can not dissipate by radiation, no cold part being nearby.

Ce type de bougie offre de médiocres propriétés de. résistance à la corrosion.This type of candle has mediocre properties. corrosion resistance.

La Fig. 3 montre une bougie suivant l'invention qui comporte des moyens pour dissiper à la fois la chaleur du bec de l'isolant et de l'extrémité 6 de l'électrode sur toute la longueur de ceux-ci par rayonnement, ainsi que la chaleur de l'électrode de masse, par conduction, tandis que l'extrémité 8 du bec de l'isolant et celle 6 de l'électrode centrale sont partiellement exposées au front de flammes de la chambre de combustion, en saillie dans celle-ci.Fig. 3 shows a candle according to the invention which comprises means for dissipating both the heat from the nozzle of the insulator and from the end 6 of the electrode over the entire length of the latter by radiation, as well as the heat of the ground electrode, by conduction, while the end 8 of the spout of the insulator and that 6 of the central electrode are partially exposed to the flame front of the combustion chamber, projecting therein.

Ces moyens sont constitués par un appendice massif 12 qui est solidaire du bord du culot 2 et prolonge celui-ci en s'étendant axialement au moins jusqu'au niveau de l'extrémité 6 de l'électrode centrale, en constituant à la fois un support massif froid pour l'électrode de masse 9 et une paroi froide entourant partiellement l'électrode centrale et le bec de l'isolant.These means consist of a massive appendage 12 which is integral with the edge of the base 2 and extends the latter by extending axially at least to the level of the end 6 of the central electrode, constituting both a solid cold support for the ground electrode 9 and a cold wall partially surrounding the central electrode and the spout of the insulator.

De préférence l'appendice au support massif 12 s'étend axialement à partir d'un arc de la périphérie du bord de l'extrémité du culot 2, qui est compris entre Ge et 120 degrés et est dé préférence égal au quart de la circonférence.Preferably the appendix to the solid support 12 extends axially from an arc of the periphery of the edge of the end of the base 2, which is between Ge and 120 degrees and is preferably equal to a quarter of the circumference .

L'électrode de masse 9 constituée par un petit barreau en alliage au nickel classique utilisé pour les électrodes de masse des bougies est fixé par une extrémité sur la face interne du support 12 au voisinage de l'extrémité de l'électrode centrale 4 à une distance voulue de celle-ci, soit environ 6/10 de mm.The ground electrode 9 consisting of a small rod made of conventional nickel alloy used for the spark plug ground electrodes is fixed by one end to the internal face of the support 12 in the vicinity of the end of the central electrode 4 at a desired distance from it, about 6/10 mm.

Le support 12 peut être soit venu de matière avec le bord du culot lors de la fabrication, par usinage, matriçage à froid ou autre technique appropriée, soit formé séparément et fixé sur le bord du culot, par exemple par soudage.The support 12 can either be integral with the edge of the base during manufacture, by machining, cold stamping or other suitable technique, or be formed separately and fixed to the edge of the base, for example by welding.

Son épaisseur est de façon appropriée sensiblement égale à celle de la partie du culot qu'elle prolonge ce qui facilite sa réalisation de façon économique par exemple par matriçage comme indiqué ci-dessus, De ce fait le. support 12 se trouve en fonctionnement à peu près à. la même température que le culot, de sorte que sa masse et celle du culot froides agissent à la façon d'un dissipateur de chaleur pour l'électrode de masse qu'il porte dont le volume est réduit par rapport à celui de.l'électrode de masse d'une bougie classique grâce à cet agencement.Its thickness is suitably substantially equal to that of the part of the base which it extends, which facilitates its production in an economical manner, for example by stamping as indicated above. support 12 is in operation approximately. the same temperature as the base, so that its mass and that of the cold base act like a heat sink for the mass electrode which it carries whose volume is reduced compared to that of. ground electrode of a conventional candle thanks to this arrangement.

Le support 12 constitue en même temps une paroi froide qui s'étend en face du bec de l'isolant et de l'électrode centrale sur une partie suffisante de leur périphérie pour absorber et dissiper les calories émises par rayonnement par le bec et l'électrode.The support 12 constitutes at the same time a cold wall which extends opposite the nozzle of the insulator and the central electrode over a sufficient part of their periphery to absorb and dissipate the calories emitted by radiation by the nozzle and the electrode.

On obtient ainsi, d'une part un abaissement notable de la température de l'électrode de masse 9 qui est ainsi beaucoup moins sujette à la corrosion et d'autre part un refroidissement approprié de l'électrode centrale et du bec de l'isolant qui restent par ailleurs exposés partiellement aux flammes de la combustion dans une mesure suffisante pour les maintenir entre 500 et 800°C en assurant leur nettoyage par pyrolyse.There is thus obtained, on the one hand a significant lowering of the temperature of the ground electrode 9 which is thus much less subject to corrosion and on the other hand an appropriate cooling of the central electrode and of the spout of the insulator which also remain partially exposed to the flames of combustion to an extent sufficient to maintain them between 500 and 800 ° C by ensuring their cleaning by pyrolysis.

Suivant l'exemple représenté de façon plus schématique aux Fig. 4 et 5, le support 12 présente deux bords latéraux 13 à peu près verticaux et perpendiculaires au bord d'extrémité du culot 2.According to the example shown more schematically in FIGS. 4 and 5, the support 12 has two lateral edges 13 which are approximately vertical and perpendicular to the end edge of the base 2.

Suivant le mode de réalisation représenté aux Fig. 6 et 7 le support 12 présente deux bords latéraux 14 inclinés de telle sorte que dans ce mode de réalisation ce support 12 présente en élévation la forme d'un trapèze isocèle comme représenté à la Fig. 7.According to the embodiment shown in Figs. 6 and 7 the support 12 has two side edges rails 14 inclined so that in this embodiment this support 12 has in elevation the shape of an isosceles trapezium as shown in FIG. 7.

'On voit que dans les deux modes de réalisation décrits ci-dessus l'électrode de masse 9 ne s'étend pas au-delà de l'extrémité du support 12 dans le sens axial, l'emplacement de sa fixation étant indiqué en trait interrompu.'We see that in the two embodiments described above the ground electrode 9 does not extend beyond the end of the support 12 in the axial direction, the location of its fixing being indicated in lines interrupted.

Dans les différents modes de réalisation la masse de l'électrode 9 est très inférieure à celle du support 12 et par suite ce dernier constitue un bon dissipateur de chaleur permettant d'abaisser en service la température de l'électrode de masse.In the various embodiments the mass of the electrode 9 is much less than that of the support 12 and consequently the latter constitutes a good heat sink making it possible to lower the temperature of the mass electrode in service.

La Demanderesse a constaté que les bougies telles que décrites ci-dessus ne perturbent pas le mélange dans la chambre de combustion et que leurs électrodes sont bien exposées au front de flammes et par suite sont bien nettoyées par pyrolyse. En outre la température des parties actives est maintenue dans la plage optimale.The Applicant has found that the spark plugs as described above do not disturb the mixture in the combustion chamber and that their electrodes are well exposed to the flame front and consequently are well cleaned by pyrolysis. In addition, the temperature of the active parts is kept within the optimum range.

Sans nuire au transfert de chaleur entre le bec de l'isolant et le culot 2 par l'intermédiaire du support 12, celui-ci peut être percé d'un trou 40 qui le traverse, juste au-dessous de l'électrode 9, comme représenté à la Fig. 7, permettant un balayage encore meilleur de l'extrémité 6 de l'électrode centrale par les flammes, sans pour autant nuire au transfert de calories par rayonnement, ce rayonnement se produisant principalement au niveau du bec de l'isolant.Without interfering with the heat transfer between the spout of the insulator and the base 2 via the support 12, the latter can be pierced with a hole 40 which passes through it, just below the electrode 9, as shown in Fig. 7, allowing even better sweeping of the end 6 of the central electrode by the flames, without hampering the transfer of calories by radiation, this radiation occurring mainly at the level of the nozzle of the insulator.

On comprend que l'invention permet non seulement un abaissement de la température des électrodes en service., mais également des propriétés d'auto- nettoyage par pyrolyse avec un minimum de frais de fabrication, réalisant ainsi une bougie dont la durée de vie est très nettement prolongée par rapport aux bougies classiques.It is understood that the invention allows not only a lowering of the temperature of the electrodes in service., But also self-cleaning properties by pyrolysis with a minimum of manufacturing costs, thus achieving a candle whose lifespan is very significantly extended compared to conventional candles.

Claims (10)

1 - Bougie d'allumage par étincelles pour moteur à combustion interne à allumage commandé, caractérisé en ce qu'elle comprend des moyens (12) pour évacuer à la fois la chaleur de l'électrode de masse (9), de l'électrode centrale (6) et de l'extrémité (8) du bec de l'isolant (7) de celle-ci, cette extrémité (8) étant en saillie dans la chambre de combustion dans laquelle elle est partiellement exposée au front de flammes et en est partiellement masquée par lesdits moyens (12), ceux-ci constituant un support massif pour l'électrode de masse (9).1 - Spark plug for internal combustion engine with positive ignition, characterized in that it comprises means (12) for removing both the heat from the ground electrode (9), from the electrode central (6) and the end (8) of the spout of the insulator (7) thereof, this end (8) projecting into the combustion chamber in which it is partially exposed to the flame front and is partially masked by said means (12), these constituting a solid support for the ground electrode (9). 2 - Bougie suivant la revendication 1, caractérisée en ce que lesdits moyens pour évacuer à la fois la chaleur de l'électrode de masse (9), de l'électrode centrale (6) et du bec (7) de l'isolant sont constitués par un appendice ou support massif (12) s'étendant axialement au moins jusqu'au niveau de l'extrémité de l'électrode centrale (6), et entourant partiellement celle-ci, à partir du bord du culot (2) sur un arc compris entre 60 et 120 degrés.2 - Spark plug according to claim 1, characterized in that said means for removing both the heat from the ground electrode (9), from the central electrode (6) and from the spout (7) of the insulator are constituted by an appendage or solid support (12) extending axially at least up to the level of the end of the central electrode (6), and partially surrounding the latter, from the edge of the base (2) on an arc between 60 and 120 degrees. 3 - Bougie suivant la revendication 2, caractérisée en ce que ledit arc est de préférence d'à peu près le quart de la circonférence du culot (2).3 - Candle according to claim 2, characterized in that said arc is preferably about a quarter of the circumference of the base (2). 4 - Bougie suivant l'une.quelconque des revendications 1 à 3, caractérisée en ce que ledit appendice ou support massif (12) est venu de matière avec le culot (2) de fabrication, par exemple par matriçage à froid.4 - Candle according to une.quelconque of claims 1 to 3, characterized in that said appendage or solid support (12) came integrally with the base (2) of manufacture, for example by cold stamping. 5 - Bougie suivant l'une quelconque des revendications 1 à 3, caractérisée en ce que ledit support massif (12) est formé séparément et fixé sur le bord du culot (2), par exemple par soudage.5 - Candle according to any one of claims 1 to 3, characterized in that said solid support (12) is formed separately and fixed on the edge of the base (2), for example by welding. 6 - Bougie suivant l'une quelconque des revendications précédentes, caractérisée en ce que l'électrode de masse (9) est fixée par une extrémité sur la face interne du support (12).6 - Candle according to any one of the preceding claims, characterized in that the elec ground trode (9) is fixed by one end to the internal face of the support (12). 7 - Bougie suivant l'une quelconque des revendications 1 à 6, caractérisée en ce que le support massif (12) comporte des bords latéraux (13) rectilignes perpendiculaires au bord du culot (.2).7 - Candle according to any one of claims 1 to 6, characterized in that the solid support (12) has lateral edges (13) rectilinear perpendicular to the edge of the base (.2). 8 - Bougie suivant l'une quelconque des revendications 1 à 6, caractérisée en ce que le support massif (12) comporte deux bords latéraux (14) inclinés divergents vers le bord du culot (2).8 - Candle according to any one of claims 1 to 6, characterized in that the solid support (12) has two lateral edges (14) inclined diverging towards the edge of the base (2). 9 - Bougie suivant l'une quelconque des revendications 1 à.8, caractérisée en ce que ledit appendice ou support massif (12) est percé d'un trou au niveau de l'extrémité (6) de l'électrode centrale.9 - Candle according to any one of claims 1 to.8, characterized in that said appendage or solid support (12) is pierced with a hole at the end (6) of the central electrode. 10 - Bougie suivant la revendication 3, caractérisée en ce que ledit appendice ou support massif (12) constitue une paroi froide s'étendant en regard du bec de l'isolant et de l'extrémité (6) de l'électrode centrale sur toute leur longueur en saillie dans la chambre de combustion.10 - Candle according to claim 3, characterized in that said appendage or solid support (12) constitutes a cold wall extending opposite the spout of the insulator and the end (6) of the central electrode over any their protruding length in the combustion chamber.
EP81401566A 1980-10-17 1981-10-09 Spark plug Expired EP0050552B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US06/320,799 US4527260A (en) 1981-10-09 1981-11-12 Method for seismic exploration by vertical seismic profiling and installation for its implementation

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8022227A FR2492601A1 (en) 1980-10-17 1980-10-17 IMPROVED SPARK PLUG
FR8022227 1980-10-17

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EP0050552A1 true EP0050552A1 (en) 1982-04-28
EP0050552B1 EP0050552B1 (en) 1985-05-02

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US (1) US4540912A (en)
EP (1) EP0050552B1 (en)
JP (1) JPS5798992A (en)
DE (1) DE3170317D1 (en)
ES (1) ES260801Y (en)
FR (1) FR2492601A1 (en)

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JPH09330782A (en) * 1996-06-07 1997-12-22 Ngk Spark Plug Co Ltd Spark plug
DE10129040A1 (en) * 2001-06-15 2003-01-02 Bosch Gmbh Robert spark plug
GB2391264B (en) * 2002-07-31 2005-11-30 Federal Mogul Ignition Spark plug
DE102004012927A1 (en) * 2004-03-17 2005-10-06 Robert Bosch Gmbh Spark plug for a combustion engine has carrier connected to the earth electrode with a functional part forming a spark gap to the central electrode
US7975665B2 (en) * 2007-02-23 2011-07-12 Ngk Spark Plug Co., Ltd. Spark plug and internal combustion engine provided with the same
JP4746689B2 (en) * 2009-06-22 2011-08-10 日本特殊陶業株式会社 Spark plug and manufacturing method thereof
DE102012009506A1 (en) 2011-05-27 2012-11-29 Volkswagen Aktiengesellschaft Cylinder of an internal combustion engine for a vehicle and corresponding manufacturing method, means for producing the cylinder, spark plug, internal combustion engine and vehicle
JP5599840B2 (en) 2012-04-27 2014-10-01 日本特殊陶業株式会社 Spark plug and spark plug manufacturing method
US8823251B2 (en) * 2012-07-06 2014-09-02 Denso International America, Inc. Partial shroud of spark plug for ground electrode heat dispersion
WO2016019369A1 (en) * 2014-08-01 2016-02-04 Sturm, Ruger & Company, Inc. Barrel extension for firearm
US10283940B1 (en) 2018-03-27 2019-05-07 Denso International America, Inc. Dielectric ground strap for spark improvement

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US1441444A (en) * 1919-01-20 1923-01-09 Mitchell Parker Spark plug
GB161327A (en) * 1920-01-20 1921-04-14 Robert Frederick Hall Improvements in sparking plugs
US2106449A (en) * 1934-09-12 1938-01-25 Charles R Boyd Spark plug
US2080495A (en) * 1935-06-22 1937-05-18 Dean D Francis Spark plug cooling device
US2069320A (en) * 1935-07-17 1937-02-02 Dean D Francis Spark plug
FR2325217A1 (en) * 1975-09-16 1977-04-15 New Cosmos Electric Co INTERNAL COMBUSTION ENGINE SPARK PLUG

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Publication number Publication date
DE3170317D1 (en) 1985-06-05
JPS5798992A (en) 1982-06-19
EP0050552B1 (en) 1985-05-02
FR2492601A1 (en) 1982-04-23
FR2492601B1 (en) 1983-07-22
ES260801U (en) 1982-05-01
ES260801Y (en) 1982-11-16
US4540912A (en) 1985-09-10

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