US2961563A - Slipping-spark ignition plugs - Google Patents

Slipping-spark ignition plugs Download PDF

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Publication number
US2961563A
US2961563A US725710A US72571058A US2961563A US 2961563 A US2961563 A US 2961563A US 725710 A US725710 A US 725710A US 72571058 A US72571058 A US 72571058A US 2961563 A US2961563 A US 2961563A
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US
United States
Prior art keywords
enamel
insulator
spark
slipping
spark ignition
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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.)
Expired - Lifetime
Application number
US725710A
Inventor
Peras Lucien
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Renault SAS
Regie Nationale des Usines Renault
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Renault SAS
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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C8/00—Enamels; Glazes; Fusion seal compositions being frit compositions having non-frit additions
    • C03C8/02—Frit compositions, i.e. in a powdered or comminuted form
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/062—Glass compositions containing silica with less than 40% silica by weight
    • C03C3/064—Glass compositions containing silica with less than 40% silica by weight containing boron
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/089—Glass compositions containing silica with 40% to 90% silica, by weight containing boron
    • C03C3/091—Glass compositions containing silica with 40% to 90% silica, by weight containing boron containing aluminium
    • 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
    • H01T13/38—Selection of materials for insulation

Definitions

  • This invention relates in general to spark ignition devices and more particularly to spark plugs of the type wherein the spark is produced by discharging a capacity and wherein the electrical voltage or tension and the electrode gap have such values that the spark cannot take place in the atmosphere where the ignition is required unless this spark remains in contact with a solid insulating member disposed between the electrodes.
  • spark plugs the spark ing element of which consists of two electrodes spaced about 0.004" to 0.008" apart, the inter-electrode gap being occupied by a solid-supporting insulator flush with the electrode surfaces.
  • the useful life of capacity discharge spark plugs of this character is reduced more or less by two main and different causes, namely:
  • Electrode wear whereby the relative spacing of the sparking edges increases until it is too great to enable the spark to fly between these edges;
  • This invention provides a method of manufacturing spark plugs of the type defined hereinabove, wherein the insulator disposed between the electrodes is rendered particularly apt to facilitate in a reliable and lasting manner the passage of sparks by being coated with an enamel of special composition which has a high specific inductive capacity.
  • the insulator whether cured or uncured, consisting for example of sintered alumina or clay-bound alumina, is coated on its face turned towards the chamber containing the fuel mixture to be ignited, with an enamel applied wit-h a brush, by dipping or by any other adequate means, this enamel consisting of a suspension in a liquid of the material in a finely divided state.
  • the insulator is dried and brought to the proper baking temperature in a suitable atmosphere.
  • a spark plug for capacity-discharge ignition which has an insulator of adequate shape, enamelled on its operative portion, that is, on the portion situated in the interelectrode gap on which the sparks are caused to fly and slip, is obtained.
  • the insulator is be coated" with' the aforesaid enamel may have the following composition:
  • An enamel composition particularly suitable for coating the active surface of an insulator of the kind defined hereinabove has the following composition:
  • the last four elements associated beforehand by baking are in a vitreous condition.
  • the oxides of titanium and barium, or barium titanate are thoroughly mixed by crushing the vitreous phase until a finely "divided powder is obtained.
  • This powder in the form of an aqueous suspension is then applied by means of a brush on the portion of the aluminous insulator which is to be enamelled.
  • the coated insulator is brought to the curing temperature of 800 to 1,350 C., this curing operation being effected compulsorily in a reducing atmosphere, for example of hydrogen; the enamel is obtained to the proper degree when its color is dark blue and adheres perfectly on its aluminous support.
  • the baking of the enamel may be carried out by means of a heating torch successively in the oxidizing or reducing portion of the flame, or by using any other adequate heating means of which at least the last phase is a reducing one.
  • an ignition spark plug of the slipping-spark type is illustrated diagrammatically by way of example in the single figure of the attached drawing.
  • the reference numeral 1 is the insulator
  • Z and 3 are the electrodes
  • 4 the enamel coating.
  • a slipping-spark ignition spark plug having an insulator interposed between electrodes, the active portion of said insulator being coated with a baked enamel having a high specific inductive capacity, said enamel being the nonvolatile residue of an aqueous suspension of the enamel components in a finely-divided state, said enamel consisting essentially of 5 to 30% TiO 20 to 46% BaO, 1 to 10% B 0 30 to 45% SiO 0.5 to 3% A1 0 and 1 to 9% Na O.
  • a method of manufacturing spark plugs of the type wherein a slipping-spark is produced in contact with a solid insulator, wherein the insulator interposed between the electrodes of the spark plug is rendered particularly suitable for the passage of the sparks which comprises the steps of coating the active portion of said insulator with an enamel having a high specific inductive capacity, said enamel being applied as an aqueous suspension of its components in a finely divided state, drying the insulator and baking the enamel coating upon said insulator in a reducing or nitriding atmosphere at a temperature of 800 to 1350 C., said enamel consisting essentially of 5 to 30% n0 20 to 46% BaO, 1 to 10% 3 B203, 1.0 S102, 0.5 to A1203 and 1 to N30;-
  • a method of manufacturing spark plugs of the type wherein a slipping-spark is produced in contact with a solid insulator, wherein the insulator interposed between the electrodes of the spark plug is rendered particularly suitable for the passage of the sparks which comprises the steps of coating the active portion of said insulator with an enamel having a high specific inductive capacity, said enamel being applied as an aqueous suspension of its components in a finely-divided state, drying the insulator and baking the enamel coating upon said insulator in a suitable atmosphere, said enamel consisting essen- 4 tially of 5 to 30% TiO- 20 to 46% B210, 1 to 10% B 0 30 to 45% Si0 0.5 to 3% A1 0 and l to 9% Na0 References Cited in the file of this patent UNITED STATES PATENTS a. haw

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Spark Plugs (AREA)

Description

SLIPPING-SPARK zcnmon PLUGS Filed April 1. 195a 2,961,563 SLlPPING-SPARK IGNITION PLUGS Lucien Pras, Billancourt, France, assig'nor to R'egi'e Nationale des Usines Renault, Billancourt, France This invention relates in general to spark ignition devices and more particularly to spark plugs of the type wherein the spark is produced by discharging a capacity and wherein the electrical voltage or tension and the electrode gap have such values that the spark cannot take place in the atmosphere where the ignition is required unless this spark remains in contact with a solid insulating member disposed between the electrodes. In the absence of such solid insulating member the spark ill not fly unless a considerably higher tension is used and in this case either the advantages resulting from caacity-discharge ignition must be waived or the inter- -:::trode gap must be set at a very small value of the dcr of 0.008" to 0.002"; now it is evident that this ondition is rather diflicult to meet, and furthermore as consequence of the electrode wear caused by sparks ssurring at a high rate the interelectr-ode gap would rapidly increase to a value preventing the passage of parks.
it is already known, in their application to internal combustion engines, to constitute spark plugs the spark ing element of which consists of two electrodes spaced about 0.004" to 0.008" apart, the inter-electrode gap being occupied by a solid-supporting insulator flush with the electrode surfaces. However, the useful life of capacity discharge spark plugs of this character is reduced more or less by two main and different causes, namely:
Electrode wear, whereby the relative spacing of the sparking edges increases until it is too great to enable the spark to fly between these edges;
Premature wear of the insulator due to the thermal action exerted thereon by the sparks, whereby the sparks will progressively sink inside the cartridge until they become unable to ignite the fuel mixture.
Now according to this invention it is possible to provide capacity-discharge spark plugs characterized by an extremely long useful life.
This invention provides a method of manufacturing spark plugs of the type defined hereinabove, wherein the insulator disposed between the electrodes is rendered particularly apt to facilitate in a reliable and lasting manner the passage of sparks by being coated with an enamel of special composition which has a high specific inductive capacity.
According to a typical form of embodiment of the invention, the insulator, whether cured or uncured, consisting for example of sintered alumina or clay-bound alumina, is coated on its face turned towards the chamber containing the fuel mixture to be ignited, with an enamel applied wit-h a brush, by dipping or by any other adequate means, this enamel consisting of a suspension in a liquid of the material in a finely divided state. After the coating step, the insulator is dried and brought to the proper baking temperature in a suitable atmosphere.
Thus, after fitting the insulator in the assembly, a spark plug for capacity-discharge ignition which has an insulator of adequate shape, enamelled on its operative portion, that is, on the portion situated in the interelectrode gap on which the sparks are caused to fly and slip, is obtained. The insulator is be coated" with' the aforesaid enamel may have the following composition:
f Percent S19 S IQ 45 T 1 C50 0 t0 5 An enamel composition particularly suitable for coating the active surface of an insulator of the kind defined hereinabove has the following composition:
In this enamel the last four elements associated beforehand by baking are in a vitreous condition. The oxides of titanium and barium, or barium titanate are thoroughly mixed by crushing the vitreous phase until a finely "divided powder is obtained. This powder in the form of an aqueous suspension is then applied by means of a brush on the portion of the aluminous insulator which is to be enamelled. After drying, the coated insulator is brought to the curing temperature of 800 to 1,350 C., this curing operation being effected compulsorily in a reducing atmosphere, for example of hydrogen; the enamel is obtained to the proper degree when its color is dark blue and adheres perfectly on its aluminous support.
The baking of the enamel may be carried out by means of a heating torch successively in the oxidizing or reducing portion of the flame, or by using any other adequate heating means of which at least the last phase is a reducing one.
Satisfactory results are also obtained by carrying out the last heating step in a nitriding atmosphere.
An ignition spark plug of the slipping-spark type according to this invention is illustrated diagrammatically by way of example in the single figure of the attached drawing. In this figure, the reference numeral 1 is the insulator, Z and 3 are the electrodes, and 4 the enamel coating.
I claim:
1. A slipping-spark ignition spark plug having an insulator interposed between electrodes, the active portion of said insulator being coated with a baked enamel having a high specific inductive capacity, said enamel being the nonvolatile residue of an aqueous suspension of the enamel components in a finely-divided state, said enamel consisting essentially of 5 to 30% TiO 20 to 46% BaO, 1 to 10% B 0 30 to 45% SiO 0.5 to 3% A1 0 and 1 to 9% Na O.
2. A method of manufacturing spark plugs of the type wherein a slipping-spark is produced in contact with a solid insulator, wherein the insulator interposed between the electrodes of the spark plug is rendered particularly suitable for the passage of the sparks, which comprises the steps of coating the active portion of said insulator with an enamel having a high specific inductive capacity, said enamel being applied as an aqueous suspension of its components in a finely divided state, drying the insulator and baking the enamel coating upon said insulator in a reducing or nitriding atmosphere at a temperature of 800 to 1350 C., said enamel consisting essentially of 5 to 30% n0 20 to 46% BaO, 1 to 10% 3 B203, 1.0 S102, 0.5 to A1203 and 1 to N30;-
3. A method of manufacturing spark plugs of the type wherein a slipping-spark is produced in contact with a solid insulator, wherein the insulator interposed between the electrodes of the spark plug is rendered particularly suitable for the passage of the sparks, which comprises the steps of coating the active portion of said insulator with an enamel having a high specific inductive capacity, said enamel being applied as an aqueous suspension of its components in a finely-divided state, drying the insulator and baking the enamel coating upon said insulator in a suitable atmosphere, said enamel consisting essen- 4 tially of 5 to 30% TiO- 20 to 46% B210, 1 to 10% B 0 30 to 45% Si0 0.5 to 3% A1 0 and l to 9% Na0 References Cited in the file of this patent UNITED STATES PATENTS a. haw

Claims (1)

1. A SLIPPING-SPARK IGNITION SPARK PLUG HAVING AN INSULATOR INTERPOSED BETWEEN ELECTRODES, THE ACTIVE PORTION OF SAID INSULATOR BEING COATED WITH A BAKED ENAMEL HAVING A HIGH SPECIFIC INDUCTIVE CAPACITY, SAID ENAMEL BEING THE NON-VOLATILE RESIDUE OF AN AQUEOUS SUSPENSION OF THE ENAMEL COMPONENTS IN A FINELY-DIVIDED STATE, SAID ENAMEL CONSISTING ESSENTIALLY OF 5 TO 30% TIO2, 20 TO 46% BAO, 1 TO 10% B2O3, 30 TO 45% SIO2, 0.5 TO 3% AL2O3 AND 1 TO 9% NA2O.
US725710A 1957-04-24 1958-04-01 Slipping-spark ignition plugs Expired - Lifetime US2961563A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR886729X 1957-04-24

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3193401A (en) * 1962-01-24 1965-07-06 Cataphote Corp High index glass composition
US3277020A (en) * 1963-12-19 1966-10-04 Int Resistance Co Glass composition and electrical resistance material made therefrom
US3427222A (en) * 1965-10-15 1969-02-11 Westinghouse Electric Corp Nuclear fuel elements
US4439707A (en) * 1980-07-23 1984-03-27 Nippon Soken, Inc. Spark plug with a wide discharge gap
US4476412A (en) * 1980-10-10 1984-10-09 Nippondenso Co., Ltd. Spark plug

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1123017A (en) * 1914-12-29 Fritz Schroeter Ignition device for internal-combustion engines.
US2010776A (en) * 1931-12-23 1935-08-06 Vitreous Enameling Company Acid resistant vitreous enamel composition
US2527884A (en) * 1949-01-29 1950-10-31 Cutler Hammer Inc Vitreous compositions and methods of making the same
US2587916A (en) * 1949-09-14 1952-03-04 Specialties Dev Corp Heat detecting cable
US2715593A (en) * 1950-09-06 1955-08-16 Steatite & Porcelain Prod Ltd Method of providing a ceramic base with a coating of blue titania and article produced thereby
US2790104A (en) * 1952-01-18 1957-04-23 Smitsvonk N V Res Lab Comp Surface discharge spark plug and method for making such a spark plug

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1123017A (en) * 1914-12-29 Fritz Schroeter Ignition device for internal-combustion engines.
US2010776A (en) * 1931-12-23 1935-08-06 Vitreous Enameling Company Acid resistant vitreous enamel composition
US2527884A (en) * 1949-01-29 1950-10-31 Cutler Hammer Inc Vitreous compositions and methods of making the same
US2587916A (en) * 1949-09-14 1952-03-04 Specialties Dev Corp Heat detecting cable
US2715593A (en) * 1950-09-06 1955-08-16 Steatite & Porcelain Prod Ltd Method of providing a ceramic base with a coating of blue titania and article produced thereby
US2790104A (en) * 1952-01-18 1957-04-23 Smitsvonk N V Res Lab Comp Surface discharge spark plug and method for making such a spark plug

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3193401A (en) * 1962-01-24 1965-07-06 Cataphote Corp High index glass composition
US3277020A (en) * 1963-12-19 1966-10-04 Int Resistance Co Glass composition and electrical resistance material made therefrom
US3427222A (en) * 1965-10-15 1969-02-11 Westinghouse Electric Corp Nuclear fuel elements
US4439707A (en) * 1980-07-23 1984-03-27 Nippon Soken, Inc. Spark plug with a wide discharge gap
US4476412A (en) * 1980-10-10 1984-10-09 Nippondenso Co., Ltd. Spark plug

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