US3742280A - Pre ignition gap for combustion engine ignition systems - Google Patents

Pre ignition gap for combustion engine ignition systems Download PDF

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Publication number
US3742280A
US3742280A US00198228A US3742280DA US3742280A US 3742280 A US3742280 A US 3742280A US 00198228 A US00198228 A US 00198228A US 3742280D A US3742280D A US 3742280DA US 3742280 A US3742280 A US 3742280A
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US
United States
Prior art keywords
percent
ignition system
gas
electrodes
ignition
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.)
Expired - Lifetime
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US00198228A
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English (en)
Inventor
G Siegle
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Robert Bosch GmbH
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Robert Bosch GmbH
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Filing date
Publication date
Priority claimed from DE19702056235 external-priority patent/DE2056235C3/de
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
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Publication of US3742280A publication Critical patent/US3742280A/en
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • H01T13/40—Sparking plugs structurally combined with other devices
    • H01T13/41—Sparking plugs structurally combined with other devices with interference suppressing or shielding means
    • 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
    • H01T13/46—Sparking plugs having two or more spark gaps
    • H01T13/462—Sparking plugs having two or more spark gaps in series connection
    • H01T13/465—Sparking plugs having two or more spark gaps in series connection one spark gap being incorporated in the sparking plug

Definitions

  • the free ends of the electrodes are spaced apart at a 5 Ref r d distance of between 1 and 5 mm and at last in the re- 9 ences I e gion of the free ends the electrodes are composed of a UNITED STATES PATENTS material which is resistant to vaporization and disinte- 2,215,300 9/1940 Ryde 313/184 gration. 2,275,739 3/1942 Dellian et a1. 313/184 X 2,505,150 4/1950 Schwartzwalder et a1 313/124 X 31 Claims, 3 Drawing Figures k a est-2m- If I [074,
  • the present invention relates generally to ignition systems for internal combustion engines, and more particularly to pre-ignition spark gaps for use in such ignition systems.
  • the invention also relates to a method of making electrodes for such pre-ignition spark gaps.
  • the spark plug is fouled, that is if for instance the ceramic body which electrically insulates the electrodes of the spark plug from one another, is for example coated with a layer of soot and lead residue, or if it is wet or oily, then the thus existing electrical leakage path or short permits sufficient energy to be drained off to the electrodes during the build-up of potential, so that the necessary ignition potential or voltage cannot be reached.
  • pre-ignition gaps With the potential benefits to be derived from .preignition gaps thus being well known, a variety of attempts has been made to provide effective as well as relatively inexpensive pre-ignition gaps for use with ignition systems of combustion engines. Attempts have been made to provide such pre-ignition gaps either as separate components which are for instance accommodated in the spark plug connectors, or as integral componentsof the spark plugs themselves. In particular it is known to provide spark plugs in which the preignition gaps are incorporated as integral components, wherein the gas-filled'compartment of the pre-ignition gap is constituted by a bore provided in the spark plug itself and communicating with the ambient atmosphere.
  • vented gaps have, however, been found to be less than fully satisfactory because the electrical characteristics of such pre-ignition gaps are not independent over the life time of the spark plug itself of the ignition frequency, the temperature and the ambient humidity. lnstead, after they have been placed in service they develop nitric oxides and exhibit an ignition voltage which initially rises with the number of spark; if condensation of moisture in the discharge compartment of the electrodes occur the ignition voltage decreases to ineffective values below 5 kV.
  • Such pre-ignition gaps utilizes an evacuated discharge chamber, or a closed discharge chamber which is filled with a mixture of N and 0, after the electrodes of the pre-ignition gap have previously been treated for a period of between 20 and 40 hours in air.
  • These preliminary treatments of the electrodes require of course substantial expenditures in terms of time and labor and tend to make such constructions expensive.
  • these constructions have the disadvantage that oxides form in their discharge spaces which atomize or vaporize off the electrodes and form a coating on the inner wall bounding the discharge chamber; this coating may lead to shorting along the wall and to a decrease in the ignition potential as a result of a disturbance of the electric field between the electrodes caused by the coating.
  • the discharge chamber diameter is small in such pre-ignition gaps, the gas composition in the chamber is changed as a result of such occurrences and this in turn changes the ignition voltage and its frequency dependency.
  • a concomitant object of the invention is to provide such an improved pre-ignition gap which in a simple manner assures a reliable ignition of even. lean fuel-air mixtures.
  • one feature of the invention resides in an ignition system for combustion engines, and more particularly in a pre-ignition gap in such an ignition system for operation at an ignition voltage of between substantially 8,000 and 30,000 volts.
  • This pre-ignition gap comprises, briefly stated, wall means surrounding a closed compartment, and a pair of electrodes in this .compartment and having juxtaposed free ends spaced from another at a distance between substantiallyl and 5 mm, such electrodes being composed at least in the region of sparking of a material resistant to vaporizing and disintegration.
  • a body of gas chemically insert relative to the electrodes is accommodated in the compartment and surrounds the electrodes at a pressure of between substantially l and i0 atmospheres.
  • Sparking at this novel pre-ignition gap results in a steep voltage increase which in turn assures that the ignition energy will not flow off via any existing short or leakage path, but instead will result in sparking at the spark gap of the subsequently arranged spark plug.
  • the novel pre-ignition gap supplies -as a substantial improvement over the known constructionsan after-discharge lasting between 0.2 and 1 ms and free of after sparking; this after discharge is maintained at least during the lifetime of a spark plug independently of the ambient temperature, the ambient humidity and the sparking frequency and is obtained right from the beginning of the formation of each spark, without any break-in period.
  • a pre-ignition gap whose overall dimensions are such that it can be readily incorporated either in a spark plug connector or in a bore provided in the body of a spark plug itself.
  • the electrodes of the novel preignition gap will be accommodated in a glass tube which defines the gas-filled compartment and in whose wall they are fused.
  • the gas filling the compartment is advantageously nitrogen with a degree of purity of at least 98 percent.
  • the gas compartment may, instead of being filled with nitrogen, be filled with argon having a degree of purity of 99 percent, or with a mixture of argon and nitrogen and, if desired, an additive of up to 10 percent preferably 0.5-2 percentof hydrogen or noble gases.
  • the spacing between the juxtaposed free ends of the electrodes of the novel pre-ignition gap should be between approximately l'and 5 mm, and is preferably between approximately ].5 and 3 mm, in-order to maintain the voltage of the after-discharge as low as possible; in other words, the voltage should be maintained at values lower than one quarter of the ignition voltage, preferably less than one tenth of the ignition voltage of the pre-ignition gap.
  • the electrodes of the novel pre-ignition gap itself may be configurated in pin-shape like configuration or in nail-shaped configuration, so that they can be readily mounted even in small and narrow compartments.
  • the diameter of a pin-shaped electrode will be approximately 2 mm, the diameter of the nail head up to approximatelyS mm.
  • the electrodes can of course also be configurated in plate-shaped or in potshaped configuration.
  • the electrodes or at least those portions thereof where the spark develops, be made only of materials resistant to vaporization or disintegration.
  • This for instance includes nitrides of Al, Ce, Hf, La,
  • Nb, Ta, Ti, V and Zr Nb, Ta, Ti, V and Zr. It also includes mixtures of such nitrides having an oxide or oxide nitride content corresponding to an oxygen content of less than 25 atomic per cent of the combination. Particularly suitable, as tests have shown, are electrodes which in the region of the developing spark contain zirconium nitride of at least percent by weight, preferably 99 percent by weight.
  • the electrodes for the novel pre-ignition gap may be made by producing an electrode base body of wolfram or another suitable metal, on which one of the metals Al, Ce, Hf, La, Nb, Ta, Ti, V or Zr, or a mixture of these metals is deposited, whereupon at least at the surface this metal is converted into its (or their-provided a mixture of metals is involved-) nitrides by processing in an atmosphere containing nitrogen or ammonium.
  • the nitrides may also be deposited on the electrode base body by plasma spraying as described in Metal 24/1970, page 823 or by deposition directly out of the gaseous phase as described in Pohl et al, Vapor Deposition, Wiley 1966.
  • FIG. 1 illustrates in somewhat diagrammatic form one embodiment of the invention
  • FIG. 2 illustrates the embodiment of FIG. 1 incorporated in a spark plug connector
  • FIG. 3 illustrates the embodiment of FIG. 1 incorporated directly in a spark plug.
  • the illustrated pre-ignition gap shown in FIG. 1 has a glass tube 10 whose outer diameter in this instance is 4.5 mm and whose length 'is 20 mm.
  • the electrodes of the pre-ignition gap are here illustrated as each consisting of an electrode base body 11 of wolfram wire which extends through the'wall of the tube 10 from the exterior to the'interior thereof and is fused into this wall.
  • the free ends of the wolfram wires 11 are provided in the region of the spark devel opment with coatings 12 of 99 percent by weight of zirconium nitride which in this embodiment is directly deposited by a plasma deposition.
  • the oxygen content of the nitride after application is less than 25 atomic per cent of the combination.
  • the spacing between the free ends of the complete electrodes 12 is 2 mm.
  • the interior of the tube is filled with gas under pressure which in this embodiment is assumed to be at 4 atmospheres, but which may be between 1 and 10 atmospheres.
  • the gas here is 98 percent nitrogen and 2 percent hydrogen.
  • FIG. 2 shows the pre-ignition gap according to the present invention incorporated in a spark plug connector.
  • the connector has an insulating body surrounded by a metallic shield 16.
  • the pre-ignition gap 19 is accommodated in a protective sleeve 20 which advantageously is in form of a section of silicon tubing.
  • the components l7-23 with the exception of the spring 18- are surrounded and embedded in the synthetic plastic material of the member 15.
  • FIG. 3 shows that the novel pre-ignition gap of FIG. 1 can also be incorporated directly in a spark plug itself.
  • the spark plug has a housing 25 provided with a thread 26, a mass electrode 27 and a copper-asbestos seal 28.
  • the spark plug has an insulator 29 provided with a bore of passage of 55 mm diameter.
  • a center electrode 30 of nickel and a pressure bolt 31 of steel are mounted in the lower region of this bore with the aid of an electrically conductive glass melt 32.
  • a pre-ig nition gap 33 is supported against the bolt 31 and has a connecting electrode 33 which extends into a bore in the bolt 31 and another electrode 33' which engages in a depression of a member 35 which is subjected to the pressure of a spring 34.
  • the end of the spring 34 which faces away from the pre-ignition gap 33 is supported against a threaded member 36 mounted in the insulator 29, with a bolt 36' and a nut 37.
  • the construction of the pre-ignition gap 33 is identically the same as in FIGS. 1 and 2, both as to its structural features, including the provision of the body of gas, and its overall dimensions.
  • the material of the electrodes and the spacing between the electrodes, the pressure conditions and the composition of the gas or gas mixture are all the same.
  • a pre-ignition gap comprising wall means surrounding a closed compartment; a pair of electrodes in said compartment having juxtaposed free ends spaced from one another, at least one of said electrodes being composed in at least the region of sparking in excess of 90 percent by weight of at least one metallic nitride; and a body of gas chemically inert relative to said electrodes accommodated in said compartment and surrounding said electrodes.
  • said gas comprises nitrogen of a purity of at least 98 percent, and a hydrogen component of up to 10 percent of the total quantity of said body of gas.
  • said gas is a mixture of argon and nitrogen with an added component of hydrogen amounting to up to 10 percent of the total quantity of said body of gas.
  • said gas is a mixture of argon and nitrogen with an added component of a noble gas amounting to up to percent of the total quantity of said body of gas.
  • nitride is selected from the group composed of nitrides of Al, Ce, I-If, La, Nb, Ta, Ti, V and Zr.
  • nitride is a mixture selected from the group of nitrides of Al, Ce, Hf, La, Nb, Ta, Ti, V and Zr, with an oxide or oxinitride content which corresponds to an oxygen content of the mixture of less than 25 atom percent.
  • said one electrode is composed in said sparking region of at least 90 percent by weight of zirconium nitride.
  • said nitride is in the form of sintered particles, and wherein the average diameter of said sintered particles at the surface of said one electrode is smaller than the base diameter of sparks originating at said gap.
  • a pre-ignition gap comprising wall means surrounding a closed compartment; a pair of electrodes in said compartment having juxtaposed free ends spaced from one another, at least one of said electrodes being composed in at least the region of sparking in excess of 90 percent by weight of at least one material selected from the group consisting of nitrides of Al, Ce, l-If, La, Nb, Ta, Ti, V and Zr, provided that the oxide or oxinitride content of said material corresponds to an oxygen content of less than 25 atom percent of said material; and a body of gas chemically inert relative to said electrodes accommodated in said compartment and surrounding said electrodes at a pressure of between substantially l and 10 atmospheres, said gas being composed of at least one substance selected from the group consisting of nitrogen of at least 98 percent purity and argon of at least 99 percent purity, said gas containing less than substantially 5.10 percent of impurities such as water, oxygen and halogens.
  • said gas comprises up to 10 percent of an added component, said added component being composed of at least one substance selected from the group consisting of hydrogen and noble gases.
  • said material comprises at least 90 percent by weight of sintered particles, the diameter of said particles at the surface of said one electrode being smaller than the base diameter of sparks originating at said gap.
  • a pre-ignition gap comprising wall means surrounding a closed compartment; a pair of electrodes in said compartment having juxtaposed free ends spaced from one another, at least one of said electrodes being composed in at least the region of sparking in excess of 90 percent by weight of a material selected from the group consisting of nitrides of Al, Ce, Hf, La, Nb, Ta, Ti, V and Zr; and a body of gas chemically inert relative to said electrodes accommodated in said compartment and surrounding said electrodes at a pressure of between substantially l and I0 atmospheres, said gas being composed of at least one substance selected from the group consisting of nitrogen of at least 98 percent purity and argon of at least 99 percent purity, said gas containing less than substantially 5.10 percent of impurities such as water, oxygen ahd halogens.
  • said gas comprises up to 10 percent of an added component, said added component being composed of at least one substance selected from the group consisting of hydrogen and noble gases.
  • said material comprises at least 90 percent by weight of sintered particles, the diameter of said particles at the surface of said one electrode being smaller than the base diameter of sparks originating at said gap.

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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)
US00198228A 1970-11-16 1971-11-12 Pre ignition gap for combustion engine ignition systems Expired - Lifetime US3742280A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19702056235 DE2056235C3 (de) 1970-11-16 Spulen-Zündanlage zum Betrieb von Brennkraftmaschinen, mit in ihre Hochspannungsleitungen eingeschalteten Vorfunkenstrecken

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US3742280A true US3742280A (en) 1973-06-26

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US00198228A Expired - Lifetime US3742280A (en) 1970-11-16 1971-11-12 Pre ignition gap for combustion engine ignition systems

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US (1) US3742280A (enExample)
JP (1) JPS5132180B1 (enExample)
AT (1) AT309910B (enExample)
AU (1) AU448942B2 (enExample)
BE (1) BE775401A (enExample)
BR (1) BR7107598D0 (enExample)
CH (1) CH537521A (enExample)
CS (1) CS159794B2 (enExample)
FR (1) FR2114370A5 (enExample)
GB (1) GB1366529A (enExample)
HU (1) HU163836B (enExample)
IT (1) IT940574B (enExample)
RO (1) RO60744A (enExample)
SE (1) SE395510B (enExample)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3956657A (en) * 1972-07-18 1976-05-11 Robert Bosch G.M.B.H. Pre-ignition gap
EP0147613A3 (de) * 1983-12-24 1985-08-07 Robert Bosch Gmbh Zündkerze für eine Brennkraftmaschine
US5145433A (en) * 1989-07-14 1992-09-08 Yazaki Corporation High tension cable device and process of producing the same
US5185556A (en) * 1989-07-19 1993-02-09 Yazaki Corporation Gas-filled discharge tube
EP0488216A3 (enExample) * 1990-11-29 1994-04-27 Yazaki Corp
RU2190911C2 (ru) * 2000-11-02 2002-10-10 Булкин Александр Михайлович Система зажигания
US20110139107A1 (en) * 2009-12-15 2011-06-16 John Burrows Spark ignition device for an internal combustion engine and central electrode assembly therefor
US20190296525A1 (en) * 2016-11-25 2019-09-26 Robert Bosch Gmbh Spark plug

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE428605B (sv) * 1979-03-19 1983-07-11 Aimpoint Ab Optiskt riktmedel for skjutvapen
JPH0322388U (enExample) * 1989-07-14 1991-03-07
US5166574A (en) * 1989-07-14 1992-11-24 Yazaki Corporation High-tension cable device
JPH0384558U (enExample) * 1989-12-20 1991-08-27
JPH0494076A (ja) * 1990-08-09 1992-03-26 Yazaki Corp 放電管内蔵型点火プラグ装置

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3956657A (en) * 1972-07-18 1976-05-11 Robert Bosch G.M.B.H. Pre-ignition gap
EP0147613A3 (de) * 1983-12-24 1985-08-07 Robert Bosch Gmbh Zündkerze für eine Brennkraftmaschine
US5145433A (en) * 1989-07-14 1992-09-08 Yazaki Corporation High tension cable device and process of producing the same
US5185556A (en) * 1989-07-19 1993-02-09 Yazaki Corporation Gas-filled discharge tube
EP0488216A3 (enExample) * 1990-11-29 1994-04-27 Yazaki Corp
RU2190911C2 (ru) * 2000-11-02 2002-10-10 Булкин Александр Михайлович Система зажигания
US20110139107A1 (en) * 2009-12-15 2011-06-16 John Burrows Spark ignition device for an internal combustion engine and central electrode assembly therefor
US8707922B2 (en) 2009-12-15 2014-04-29 Federal Mogul Ignition Company Spark ignition device for an internal combustion engine and central electrode assembly therefor
US10027092B2 (en) 2009-12-15 2018-07-17 Federal-Mogul Ignition Company Spark ignition device for an internal combustion engine and central electrode assembly therefore
US20190296525A1 (en) * 2016-11-25 2019-09-26 Robert Bosch Gmbh Spark plug
US10886705B2 (en) * 2016-11-25 2021-01-05 Robert Bosch Gmbh Spark plug having a center electrode with improved thermal properties

Also Published As

Publication number Publication date
AU448942B2 (en) 1974-05-30
IT940574B (it) 1973-02-20
BR7107598D0 (pt) 1973-02-20
AU3569371A (en) 1973-05-24
BE775401A (fr) 1972-03-18
JPS5132180B1 (enExample) 1976-09-10
CS159794B2 (enExample) 1975-01-31
DE2056235A1 (de) 1972-05-31
RO60744A (enExample) 1976-07-15
DE2056235B2 (de) 1975-12-04
HU163836B (enExample) 1973-11-28
FR2114370A5 (enExample) 1972-06-30
SE395510B (sv) 1977-08-15
CH537521A (de) 1973-05-31
AT309910B (de) 1973-09-10
GB1366529A (en) 1974-09-11

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