EP0020200A1 - Zündkerze - Google Patents

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Publication number
EP0020200A1
EP0020200A1 EP80400568A EP80400568A EP0020200A1 EP 0020200 A1 EP0020200 A1 EP 0020200A1 EP 80400568 A EP80400568 A EP 80400568A EP 80400568 A EP80400568 A EP 80400568A EP 0020200 A1 EP0020200 A1 EP 0020200A1
Authority
EP
European Patent Office
Prior art keywords
electrode
igniter plug
center electrode
cylindrical center
tip
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.)
Withdrawn
Application number
EP80400568A
Other languages
English (en)
French (fr)
Inventor
Gilbert Grant Warren
Colin Anthony Johnson
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.)
Bendix Corp
Original Assignee
Bendix Corp
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 Bendix Corp filed Critical Bendix Corp
Publication of EP0020200A1 publication Critical patent/EP0020200A1/de
Withdrawn legal-status Critical Current

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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
    • H01T13/46—Sparking plugs having two or more spark gaps
    • H01T13/467—Sparking plugs having two or more spark gaps in parallel connection
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T13/00—Sparking plugs
    • H01T13/20—Sparking plugs characterised by features of the electrodes or insulation
    • H01T13/39—Selection of materials for electrodes

Definitions

  • igniter plugs are used in engines, such as aircraft engines, to provide the spark for ignition of fuel.
  • Such plugs comprise a central electrode that is composed of tungsten or other conductive material and an outer annular electrode spaced therefrom, to provide an air gap, with conductivity established between the center electrode and an electrical source.
  • the annular electrode generally serves as a ground.
  • a ceramic insulator is provided in the air gap.
  • tungsten as the material from which the center electrode is formed has been preferred.
  • tungsten oxide is sometimes formed on the electrode surface which causes the electrode surface to expand and exercise forces on the initially spaced ceramic insulator, causing cracks in the insulator top. Such cracks shorten the effective life of the igniter plug.
  • an igniter plug comprising a cylindrical center electrode supported by a conductive pin, an annular electrode surroud- ing the cylindrical center electrode and spaced therefrom by an air gap, and an insulating sleeve intermediate the electrodes, in which there is provided a nickel coating over at least the exposed surface of the cylindrical center electrode.
  • Such nickel coating by preventing growth of tungsten oxide on the surface of the cylindrical central electrode allows the production of a stable, long life igniter plug.
  • the igniter plug 1 the tip of which is illustrated, comprises an outer or annular electrode or conductive shell 3, preferably of stainless steel and tungsten alloy, and an inner or center electrode 5 of tungsten.
  • the center electrode 5 is of general cylindrical configuration, with a circular wall 7, exposed end 9 and support end 11.
  • the center electrode is supported by a pin or rod 13, which is of an electrically conductive material such as a nickel ferrous alloy, and is attached to the pin by welding or other attachment means.
  • the annular electrode 3 and center electrode 5 are spaced from each other by an air gap 15.
  • an insulating sleeve 17 Provided within the air gap 15, intermediate the electrodes 3 and 5, is an insulating sleeve 17.
  • the conductive pin 13 also has thereabout a pin insulating member 19.
  • the insulating sleeve 17 and member 19 are preferably of a ceramic insulating material, such as alumina based ceramic insulators known in the art.
  • the present invention provides a coating of nickel completely about the exposed surface of the tungsten electrode.
  • This coating illustrated as coating 21 in the drawing, provides exceptional stability and long life for the center electrode 5.
  • the nickel coating in addition to covering the complete surface area of circular wall 7, exposed end 9 and support end 11 of the tungsten electrode 5, also covers a portion of the supporting pin 13 adjacent the center electrode to provide complete encasement of the electrode even at welding points.
  • the thickness of the nickel coating that is deposited on the electrode, such as by electroplating, should be between about 25 to 75 microns. Preferably, the thickness of the coating is on the order of 50 microns.
  • the nickel coating in the present invention at a thickness of 25 to 75 microns is applied to the electrode tip and part of the conductive pin by electroplating. Diffusion of the nickel into the tip and the pin is achieved by heating the assembly to a temperature of about 1093°C under influence of a vacuum, using a maximum pressure of about 1 x 10 -4 torr.
  • the conductive shell 3 is comprised of a main shell 23, which is stainless steel, and a shell tip portion 25 which is composed of tungsten alloy, with the two portions attached by brazing.
  • a collar 27 is provided about the inner circumference of the main shell 23, which collar is affixed to the shell by plug welds 29. With the provision of the collar 27, the main insulator or pin insulating member 19 telescopes freely into the tip insulator 17 but does not firmly abut the latter. Thus, the shell will not be in a longitudinal stress condition during thermal differential contraction when the igniter cools down from high operating temperatures.
  • the tungsten center electrode has a nickel coating of 50 micron thickness over the exposed surface and a portion of the pin supporting the same, such plugs were compared with plugs without such a coating.
  • a plug according to the present invention was subjected to voltage testing, both dry and wet, using an exciter, followed by ten minutes of sparking with fuel dripped on the tip. This was followed by a further voltage test. Subsequently, the igniter was placed in a test fixture for a heat cycle at 650°C at the tip lasting five hours, followed by inspection for cracks in the ceramic tip insulator sleeve. This sequence of voltage test, sparking test and temperature test was repeated until fifty hours of the temperature exposure was accomplished. The plug of the present invention completed the full ten cycles of five hours each at 650°C and showed no cracks in the tip insulator.
  • a plug without the nickel coating lasted only three cycles of five hours each at 650°C, according to the above test and, after the end of the third cycle, the tip insulator showed two radial cracks and testing was stopped.
  • the present invention thus provides an igniter plug having a tungsten tip that can withstand high temperature operation without cracking of the tip insulator so as to provide stability and many hours of operation of the igniter plug.

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  • Spark Plugs (AREA)
EP80400568A 1979-06-04 1980-04-25 Zündkerze Withdrawn EP0020200A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US4504279A 1979-06-04 1979-06-04
US45042 1979-06-04

Publications (1)

Publication Number Publication Date
EP0020200A1 true EP0020200A1 (de) 1980-12-10

Family

ID=21935705

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80400568A Withdrawn EP0020200A1 (de) 1979-06-04 1980-04-25 Zündkerze

Country Status (1)

Country Link
EP (1) EP0020200A1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT413904B (de) * 2003-09-19 2006-07-15 Ge Jenbacher Ag Zündkerze

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB119073A (en) * 1917-09-17 1918-09-17 George Elliot Turnbull Improvements in Electric Ignition Apparatus for Internal Combustion Engines.
US3017532A (en) * 1956-02-27 1962-01-16 Gen Am Transport Electrical elements
US3356882A (en) * 1965-10-21 1967-12-05 Ford Motor Co Spark plug having the center electrode sheath with a nickel alloy

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB119073A (en) * 1917-09-17 1918-09-17 George Elliot Turnbull Improvements in Electric Ignition Apparatus for Internal Combustion Engines.
US3017532A (en) * 1956-02-27 1962-01-16 Gen Am Transport Electrical elements
US3356882A (en) * 1965-10-21 1967-12-05 Ford Motor Co Spark plug having the center electrode sheath with a nickel alloy

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT413904B (de) * 2003-09-19 2006-07-15 Ge Jenbacher Ag Zündkerze
US7408293B2 (en) 2003-09-19 2008-08-05 Ge Jenbacher Gmbh & Co Ohg Spark plug including ground elcetrode carrier casing

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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

Designated state(s): FR GB

17P Request for examination filed

Effective date: 19800430

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

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19820926

RIN1 Information on inventor provided before grant (corrected)

Inventor name: WARREN, GILBERT GRANT

Inventor name: JOHNSON, COLIN ANTHONY