US2391455A - Spark plug and electrode therefor - Google Patents
Spark plug and electrode therefor Download PDFInfo
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- US2391455A US2391455A US491748A US49174843A US2391455A US 2391455 A US2391455 A US 2391455A US 491748 A US491748 A US 491748A US 49174843 A US49174843 A US 49174843A US 2391455 A US2391455 A US 2391455A
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- tungsten
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- electrode
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- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 44
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 35
- 229910052721 tungsten Inorganic materials 0.000 description 35
- 239000010937 tungsten Substances 0.000 description 35
- 229910052697 platinum Inorganic materials 0.000 description 22
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 20
- 239000000203 mixture Substances 0.000 description 17
- 229910045601 alloy Inorganic materials 0.000 description 11
- 239000000956 alloy Substances 0.000 description 11
- 229910052751 metal Inorganic materials 0.000 description 10
- 239000002184 metal Substances 0.000 description 10
- 229910052759 nickel Inorganic materials 0.000 description 10
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 8
- 229910001260 Pt alloy Inorganic materials 0.000 description 8
- 239000011733 molybdenum Substances 0.000 description 8
- 229910052750 molybdenum Inorganic materials 0.000 description 7
- 229910052790 beryllium Inorganic materials 0.000 description 6
- ATBAMAFKBVZNFJ-UHFFFAOYSA-N beryllium atom Chemical compound [Be] ATBAMAFKBVZNFJ-UHFFFAOYSA-N 0.000 description 6
- 238000010276 construction Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 230000003628 erosive effect Effects 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 239000010953 base metal Substances 0.000 description 4
- 229910001182 Mo alloy Inorganic materials 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 229910052702 rhenium Inorganic materials 0.000 description 3
- WUAPFZMCVAUBPE-UHFFFAOYSA-N rhenium atom Chemical compound [Re] WUAPFZMCVAUBPE-UHFFFAOYSA-N 0.000 description 3
- 229910000952 Be alloy Inorganic materials 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 229910000990 Ni alloy Inorganic materials 0.000 description 2
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- 238000007792 addition Methods 0.000 description 2
- QVQLCTNNEUAWMS-UHFFFAOYSA-N barium oxide Chemical compound [Ba]=O QVQLCTNNEUAWMS-UHFFFAOYSA-N 0.000 description 2
- 229910052796 boron Inorganic materials 0.000 description 2
- 239000010941 cobalt Substances 0.000 description 2
- 229910017052 cobalt Inorganic materials 0.000 description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000009760 electrical discharge machining Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- ZMCCBULBRKMZTH-UHFFFAOYSA-N molybdenum platinum Chemical compound [Mo].[Pt] ZMCCBULBRKMZTH-UHFFFAOYSA-N 0.000 description 2
- 239000010955 niobium Substances 0.000 description 2
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- HWLDNSXPUQTBOD-UHFFFAOYSA-N platinum-iridium alloy Chemical class [Ir].[Pt] HWLDNSXPUQTBOD-UHFFFAOYSA-N 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- IATRAKWUXMZMIY-UHFFFAOYSA-N strontium oxide Chemical compound [O-2].[Sr+2] IATRAKWUXMZMIY-UHFFFAOYSA-N 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 229910000599 Cr alloy Inorganic materials 0.000 description 1
- 229910000881 Cu alloy Inorganic materials 0.000 description 1
- 229910001030 Iron–nickel alloy Inorganic materials 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 229910001252 Pd alloy Inorganic materials 0.000 description 1
- 229910000691 Re alloy Inorganic materials 0.000 description 1
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 1
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 1
- OSJAVLJEMGYHGN-UHFFFAOYSA-N [Zr].[W] Chemical class [Zr].[W] OSJAVLJEMGYHGN-UHFFFAOYSA-N 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 1
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 1
- 229940087373 calcium oxide Drugs 0.000 description 1
- 235000012255 calcium oxide Nutrition 0.000 description 1
- 239000000292 calcium oxide Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 239000000788 chromium alloy Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005294 ferromagnetic effect Effects 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 1
- 229910000464 lead oxide Inorganic materials 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- YTHCQFKNFVSQBC-UHFFFAOYSA-N magnesium silicide Chemical compound [Mg]=[Si]=[Mg] YTHCQFKNFVSQBC-UHFFFAOYSA-N 0.000 description 1
- 229910021338 magnesium silicide Inorganic materials 0.000 description 1
- 230000005291 magnetic effect Effects 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- IGOJMROYPFZEOR-UHFFFAOYSA-N manganese platinum Chemical compound [Mn].[Pt] IGOJMROYPFZEOR-UHFFFAOYSA-N 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- TVMXDCGIABBOFY-UHFFFAOYSA-N octane Chemical compound CCCCCCCC TVMXDCGIABBOFY-UHFFFAOYSA-N 0.000 description 1
- 229910052762 osmium Inorganic materials 0.000 description 1
- SYQBFIAQOQZEGI-UHFFFAOYSA-N osmium atom Chemical compound [Os] SYQBFIAQOQZEGI-UHFFFAOYSA-N 0.000 description 1
- YEXPOXQUZXUXJW-UHFFFAOYSA-N oxolead Chemical compound [Pb]=O YEXPOXQUZXUXJW-UHFFFAOYSA-N 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- DBJYYRBULROVQT-UHFFFAOYSA-N platinum rhenium Chemical compound [Re].[Pt] DBJYYRBULROVQT-UHFFFAOYSA-N 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 239000010948 rhodium Substances 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- 229910021332 silicide Inorganic materials 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 1
- PWCPANDGJPRVKW-UHFFFAOYSA-N tungsten uranium Chemical compound [W].[U] PWCPANDGJPRVKW-UHFFFAOYSA-N 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
- H01T13/00—Sparking plugs
- H01T13/20—Sparking plugs characterised by features of the electrodes or insulation
- H01T13/39—Selection of materials for electrodes
Definitions
- This invention relates to spark plugs and th electrodes therefor.
- An object of the invention is tc-improve spark plugs and the metal compositions used forthe electrodes thereof. v
- Figure 1 shows a portion of a spark plug, partly in section, illustrating the spark plug electrodes:
- Figure 2 is an end view of the 'spark'plug
- Figure 3 is a section through a portion of a modified plug
- Figure 4 is anend view of a further modification.
- the invention contemplates a spark plug having a center electrode of tungsten or a tungsten base metal composition and a side or ground electrode formed of platinum base alloy.
- the center electrode may comprise a cylindrical section II of tungsten or tungsten base metal rod welded to the end of a nickel, nickel alloy, iron alloy or copper alloy rod l2 which is embedded in the ceramic insulator I3 of th spark plug.
- the rod I2 mayconsist of an upper portion of nickel alloy to be welded to the tungsten and a copper backing to extract the heat.
- the side electrodes l may be formed of platinum alloy-wire of rectangular 'or circular cross section spot-welded to themetal shell I 4 of the plug.
- Figure 3 shows a modification wherein the side electrode is formed of a short section 30 of platinum alloy wire welded to the end of a supporting wire 3
- the side electrodes comprise bimetallic strips having a layer 40 of platinum alloy facin the center electrode welded to a'layer 4] of bas metal behind it.
- An alloy of platinum and molybdenum containing about 4% molybdenum is the preferred material.
- This alloy has a hardness of about 104 Rockwell B, and an ultimate tensile strength of 117,000 1bs. per square inch.
- This material may be used in the form of .030 inch square wire cut into pieces about A inch long which are welded onto opposite sides of the spark plug shell.
- This construction provides two sparkgaps at opposite sides of the center electrode N. This construction is economical and permits easy adjustment .of the spark gap.
- the platinum-molybdenum alloy can be readily resistance welded tothe steel shell l4. The range of compositions between 0.5 and 7.5% molybdenum, balance platinum, produces 5 the most satisfactory results. However, molybdenum will alloy with platinum. in all pr9D tions up to above 40% molybdenum and forms" solid solutions of molybdenum in the platinumthroughout this range. Compositions in. this 10 permissible range of proportions, but outside the preferred range, may
- Another platinum base alloy suitable for the side electrode is a platinum beryllium alloy containing 0.025 to 5% beryllium, balance platinum.
- the preferred. alloy .contains 0.20% beryllium.
- the beryllium has an extraordinary hardening effect on the platinum, as little as 0.05% beryllium giving a hardness equal to that of the 10% iridium-platinum alloy and 0.25% berylliumgiving a hardness equal to a 25% iridium-platinum alloy.
- Beryllium also improves'the resistance of platinum to heat. Platinum-beryllium alloys undergo a much smaller loss in weight on prolonged heat-' ving than does pure platinum.
- the electrodes are subjected to severe conditions of electric and chemical ero- 40 sion.
- the alloys used In order for the electrodes to have a lon life, it is necessary that the alloys used have a high degree of cohesion.
- the beryllium imparts a very fine grain structure to the platinum and yields an alloy of high tensile strength.
- the high octane fuels will deposit lead oxide which-at the sparking temperatures acts as a catalyst for oxygen promoting erosion by oxidation.
- Oth'er platinum alloys which can be used are alloys of platinum with rhenium, columbium or tin. All of these materials reduc the volatility of platinum and increases its strength at high temperatures.
- PATENT OFF C j In the case or platinum-rhenium alloys suitable percentages of rhenium range. from 2 to 8% the preferred range extending from 3 to 6%. Rhenium has a similar'eflect to molybdenum namely increasing the stiflness and erosion resistance of the platinum alloy.
- platinumchromium alloys containing up to chromium may be utilized since they impart i tance to erosion and strength at elevated temperatures.
- ferromagnetic platinum base alloys characterized by high coercive forces such as 1500-4000 oersteds.
- a typical composition consists of 23% cobalt or iron,'balance platinum.
- platinum alloys suitable for the purpose of the present invention are manganese platinum alloys with 1 to 15% manganese; platinum palladium alloys with 2 to palladium.
- Such other elements may include iridium, rhodium, ruthenium, osmium, tungsten and tantalum.
- the center electrode Il may be formed of fine grained tungsten or a metal composition containing a high percentage of tungsten.
- One metal composition which is suitable is formed of
- the composition can be formed by mixing the metal powders together, pressing the mixture into a compact and heating the compact to a temperature slightly above the melting point ofthe nickel. Above this temperature the molybdenum dissolves in the nickel and the tungsten particles are rapidly dissolved by the liquid phase but are reprecipitated on certain nuclei developing large round grains. This process continues until all the originally fine tungsten particles have been converted into fairly uniform grains having a diameter about 100 times those of the original particles. All voids are also eliminated in this process and the resulting product, after cooling, is a strong non-porous body of high cohesive strength.
- the tungsten content may be between 80 and 98% in compositions of this type.
- alkaline earth compoimds which are suitable are calcium-oxide, bariumoxide, calcium siliclde, magnesium silicide, strontium oxide.
- tungsten base material which is suitable for the center electrode is tungsten containing small pr rtions of boron, alloyed or combined therewith.
- grades of tungsten may be employed containing traces up to several percent of the borides and nitrides of. such metals as are contained in the fourth, fifth and sixth group of As an example a tungsten composition containing of zirconium boride may be used. It is further contemplated to use tungsten composition containing tungsten-zirconium compounds in percentages ranging from .01 to about 4 percent.
- tungsten-uranium compositions are preferred.
- Thecombination of a platinum base side electrode with a tungsten or tungsten base center electrode affords advantages over prior electrode combinations such as nickel versus nickel, nickel versus tungsten; nickel (cobalt, iron) chromium alloys versus itself or nickel. because it provides less gap growth, ease of gap adjustment, more consistent sparking voltage and longer electrode life.
- tungsten is used as a center electrode the spark plug construction permits a fairly heavy section usually of a diameter of A; inch or longer.
- Tungsten operated under such conditions excells all other metals as regards resistance to chemical attack and spark erosion. If tungsten is used however as a side electrode .the conditions are quite different. In side electrodes fairly thin sections are used and proper heat transfer cannot readily be provided. The tungsten therefore overheats, oxidizes and wears away very quickly.
- tungsten is very brittle and does not permit gap adjustment. Tests carried out with various tungsten side electrode constructions resulted in breakage of the .side electrodes when adjustment was attempted. The diiliculties of tungsten side electrodes'were overcome by providing a combination as suggested in the present invention.
- the side electrodes made in accordance with the teaching of this invention can be operated at elevated temperatures without oxidation.
- the electrodes may be used in thin sections in order to retain a low cost and flexibility of construction to permit gap adjustment.
- the mathat small proportions of oxides and silicides of alkaline earth metals may be added to the metal compositions during manufacture. However, the
- terials disclosed for side electrodes have excellent resistance to spark erosion; The electrode combination therefore is superior to all prior constructions.
- a spark plug for use in aviation engines comprising a pair of spaced electrodes, one of said electrodes being formed predominantly of platinum and the other of said electrodes being formed predominantly of tungsten.
- a spark plug for use in aviation engines comprising a pair of spaced electrodes, one of said electrodes being formed of a platinum base alloy and the other of saidelectrodes being formed of a material selected from the group consisting of g tungsten and tungsten base inetai compositions containing at least 80% tungsten.
- a spark plug for use in aviation engines comprising an insulating body, an electrode terminal extending therethrough and terminating in an exposed electrode tip formed predominantly of tungsten, a, metal shell encircling said insulating body and a second electrode tip secured thereto and disposed adjacent said first-mentioned electrode tip, the active sparking surface'ot said second tip being formed predominantly of platinum.
- a spark plug electrode combination for use in aviation engines comprising a center electrode
Landscapes
- Spark Plugs (AREA)
Description
Dec. 25, 1945. F. R. HENS EL 2,391,455
SPARK PLUG AND ELECTRODE THEREFOR Filed June 22, 1943 7&5
NICKEL, IE 02 COPPfR ALL Il 1 II I llll TUA/GSTFNOE 1 v Tun/657E TUA/GS mv BASE METAL COMPOSITION oz 325f mvomvsrs Patented Dec. 25, 1945 SPARK PLUG ELECTRODE THEREFOR Franz R. Hensel, Indianapolis, Ind., asslgnor to P. R. Mallory & 00., Inc.,- Indianapolis, Ind., a corporation of-Delawarc Application June 22, i943, Serial No. 491,748
4 Claims.
This invention relates to spark plugs and th electrodes therefor.
An object of the invention is tc-improve spark plugs and the metal compositions used forthe electrodes thereof. v
Other objects of the invention'will be apparent from the description and claims.
In the drawing: v
Figure 1 shows a portion of a spark plug, partly in section, illustrating the spark plug electrodes:
Figure 2 is an end view of the 'spark'plug;
Figure 3 is a section through a portion of a modified plug; and
Figure 4 is anend view of a further modification. I
The invention contemplates a spark plug having a center electrode of tungsten or a tungsten base metal composition and a side or ground electrode formed of platinum base alloy.
Referring to Figures 1 and 2, the center electrode may comprise a cylindrical section II of tungsten or tungsten base metal rod welded to the end of a nickel, nickel alloy, iron alloy or copper alloy rod l2 which is embedded in the ceramic insulator I3 of th spark plug. The rod I2 mayconsist of an upper portion of nickel alloy to be welded to the tungsten and a copper backing to extract the heat. The side electrodes l may be formed of platinum alloy-wire of rectangular 'or circular cross section spot-welded to themetal shell I 4 of the plug.
Figure 3 shows a modification wherein the side electrode is formed of a short section 30 of platinum alloy wire welded to the end of a supporting wire 3| of base metal such as nickel, steel, or a high heat conductivity metal such as copper sheathed with nickel.
Inthe modification of Figure 4 the side electrodes comprise bimetallic strips having a layer 40 of platinum alloy facin the center electrode welded to a'layer 4] of bas metal behind it.
An alloy of platinum and molybdenum containing about 4% molybdenum is the preferred material. This alloy has a hardness of about 104 Rockwell B, and an ultimate tensile strength of 117,000 1bs. per square inch. This material may be used in the form of .030 inch square wire cut into pieces about A inch long which are welded onto opposite sides of the spark plug shell. This construction provides two sparkgaps at opposite sides of the center electrode N. This construction is economical and permits easy adjustment .of the spark gap. The platinum-molybdenum alloy can be readily resistance welded tothe steel shell l4. The range of compositions between 0.5 and 7.5% molybdenum, balance platinum, produces 5 the most satisfactory results. However, molybdenum will alloy with platinum. in all pr9D tions up to above 40% molybdenum and forms" solid solutions of molybdenum in the platinumthroughout this range. Compositions in. this 10 permissible range of proportions, but outside the preferred range, may in some cases be used.
Platinum molybdenum alloys. when used for spark plug electrodes hav the advantages of withstanding the erosive action of the spark rel5 sulting in gap growth. In a number of alloys usedat present frequent adjustment of the 'electrodes i necessary due tosuch gap growth. long range flying it becomes necessary to have spark plugs which will not need overhaulingfor '20 long periods of time. Also in high altitude flying the spark gap must remain properly adjusted since otherwise the sparking voltage increases resulting in misfiring.
Another platinum base alloy suitable for the side electrode is a platinum beryllium alloy containing 0.025 to 5% beryllium, balance platinum. The preferred. alloy .contains 0.20% beryllium. The beryllium has an extraordinary hardening effect on the platinum, as little as 0.05% beryllium giving a hardness equal to that of the 10% iridium-platinum alloy and 0.25% berylliumgiving a hardness equal to a 25% iridium-platinum alloy.
Beryllium also improves'the resistance of platinum to heat. Platinum-beryllium alloys undergo a much smaller loss in weight on prolonged heat-' ving than does pure platinum.
In a spark plug the electrodes are subjected to severe conditions of electric and chemical ero- 40 sion. In order for the electrodes to have a lon life, it is necessary that the alloys used have a high degree of cohesion. The beryllium imparts a very fine grain structure to the platinum and yields an alloy of high tensile strength. Furthermore the high octane fuels will deposit lead oxide which-at the sparking temperatures acts as a catalyst for oxygen promoting erosion by oxidation.
Oth'er platinum alloys which can be used are alloys of platinum with rhenium, columbium or tin. All of these materials reduc the volatility of platinum and increases its strength at high temperatures.
PATENT OFF C j In the case or platinum-rhenium alloys suitable percentages of rhenium range. from 2 to 8% the preferred range extending from 3 to 6%. Rhenium has a similar'eflect to molybdenum namely increasing the stiflness and erosion resistance of the platinum alloy.
The resistance of platinum to gaseous attack.
is increased substantially by additions of 0.025 to 10% columbium. The volatility of platinum and its strength at elevated temperatures are improved by the presence of 0.01 to 5% of tin.
It is further contemplated that platinumchromium alloys containing up to chromium may be utilized since they impart i tance to erosion and strength at elevated temperatures.
It is also considered to use ferromagnetic platinum base alloys characterized by high coercive forces such as 1500-4000 oersteds. A typical composition consists of 23% cobalt or iron,'balance platinum. By using permanently magnetized side electrodes the magnetic field will help to stabilize the arc and thereby give more consistent operation.
Further platinum alloys suitable for the purpose of the present invention are manganese platinum alloys with 1 to 15% manganese; platinum palladium alloys with 2 to palladium.
The addition of other elements to platinum up to 15% is permissible provided the performance is not affected. Such other elements may include iridium, rhodium, ruthenium, osmium, tungsten and tantalum.
The center electrode Il may be formed of fine grained tungsten or a metal composition containing a high percentage of tungsten.
One metal composition which is suitable is formed of The composition can be formed by mixing the metal powders together, pressing the mixture into a compact and heating the compact to a temperature slightly above the melting point ofthe nickel. Above this temperature the molybdenum dissolves in the nickel and the tungsten particles are rapidly dissolved by the liquid phase but are reprecipitated on certain nuclei developing large round grains. This process continues until all the originally fine tungsten particles have been converted into fairly uniform grains having a diameter about 100 times those of the original particles. All voids are also eliminated in this process and the resulting product, after cooling, is a strong non-porous body of high cohesive strength.
Other tungsten compositions which can be produced by a similar process and which are suitable are:
Generally the tungsten content may be between 80 and 98% in compositions of this type.
It is often desirable to decrease the workfunction of tungsten materials used for spark plug electrodes. For this purpose it is contemplated iii) ' the periodic system.
percentage of such ingredients is preferably kept quite small as theyhave some tendency to promote erosion. The range between .01 and 3% is preferred. Among the alkaline earth compoimds which are suitable are calcium-oxide, bariumoxide, calcium siliclde, magnesium silicide, strontium oxide. v
Another tungsten base material which is suitable for the center electrode is tungsten containing small pr rtions of boron, alloyed or combined therewith. Instead of boron it is also contemplated that grades of tungsten may be employed containing traces up to several percent of the borides and nitrides of. such metals as are contained in the fourth, fifth and sixth group of As an example a tungsten composition containing of zirconium boride may be used. It is further contemplated to use tungsten composition containing tungsten-zirconium compounds in percentages ranging from .01 to about 4 percent.
For certain applications tungsten-uranium compositions are preferred.
Thecombination of a platinum base side electrode with a tungsten or tungsten base center electrode affords advantages over prior electrode combinations such as nickel versus nickel, nickel versus tungsten; nickel (cobalt, iron) chromium alloys versus itself or nickel. because it provides less gap growth, ease of gap adjustment, more consistent sparking voltage and longer electrode life. When tungsten is used as a center electrode the spark plug construction permits a fairly heavy section usually of a diameter of A; inch or longer. By a suitable backing to the tungsten it is possible to' withdraw the heat and keep the tungsten cool enough so that it will not oxidize. Tungsten operated under such conditions excells all other metals as regards resistance to chemical attack and spark erosion. If tungsten is used however as a side electrode .the conditions are quite different. In side electrodes fairly thin sections are used and proper heat transfer cannot readily be provided. The tungsten therefore overheats, oxidizes and wears away very quickly.
Furthermore tungsten is very brittle and does not permit gap adjustment. Tests carried out with various tungsten side electrode constructions resulted in breakage of the .side electrodes when adjustment was attempted. The diiliculties of tungsten side electrodes'were overcome by providing a combination as suggested in the present invention. The side electrodes made in accordance with the teaching of this invention can be operated at elevated temperatures without oxidation. The electrodes may be used in thin sections in order to retain a low cost and flexibility of construction to permit gap adjustment. The mathat small proportions of oxides and silicides of alkaline earth metals may be added to the metal compositions during manufacture. However, the
terials disclosed for side electrodes have excellent resistance to spark erosion; The electrode combination therefore is superior to all prior constructions.
. While specific embodiments of the invention have been described, it is intended to cover the invention broadly within the spirit and scope of the appended claims.
What is claimed is:
1. A spark plug for use in aviation engines comprising a pair of spaced electrodes, one of said electrodes being formed predominantly of platinum and the other of said electrodes being formed predominantly of tungsten.
2. A spark plug for use in aviation engines comprising a pair of spaced electrodes, one of said electrodes being formed of a platinum base alloy and the other of saidelectrodes being formed of a material selected from the group consisting of g tungsten and tungsten base inetai compositions containing at least 80% tungsten.
3. A spark plug for use in aviation engines comprising an insulating body, an electrode terminal extending therethrough and terminating in an exposed electrode tip formed predominantly of tungsten, a, metal shell encircling said insulating body and a second electrode tip secured thereto and disposed adjacent said first-mentioned electrode tip, the active sparking surface'ot said second tip being formed predominantly of platinum.
4. A spark plug electrode combination for use in aviation engines comprising a center electrode
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US491748A US2391455A (en) | 1943-06-22 | 1943-06-22 | Spark plug and electrode therefor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US491748A US2391455A (en) | 1943-06-22 | 1943-06-22 | Spark plug and electrode therefor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2391455A true US2391455A (en) | 1945-12-25 |
Family
ID=23953496
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US491748A Expired - Lifetime US2391455A (en) | 1943-06-22 | 1943-06-22 | Spark plug and electrode therefor |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US2391455A (en) |
Cited By (24)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2470033A (en) * | 1945-11-27 | 1949-05-10 | Mallory & Co Inc P R | Spark plug |
| US2490214A (en) * | 1945-07-19 | 1949-12-06 | Mallory & Co Inc P R | Electrical contacting element |
| US2505150A (en) * | 1945-03-17 | 1950-04-25 | Gen Motors Corp | Spark plug with auxiliary gap |
| US2514765A (en) * | 1948-11-15 | 1950-07-11 | Baker & Co Inc | Electrical resistance wire |
| US2642053A (en) * | 1948-07-16 | 1953-06-16 | Baker & Co Inc | Electrode for sparking plugs and their manufacture |
| US2737561A (en) * | 1955-10-10 | 1956-03-06 | Baker & Co Inc | Potentiometer |
| US2819162A (en) * | 1954-09-29 | 1958-01-07 | Secon Metals Corp | Precious metal electrical resistance wires |
| US2920223A (en) * | 1960-01-05 | Pxras | ||
| US2927238A (en) * | 1958-10-06 | 1960-03-01 | Gen Motors Corp | Spark plug |
| US3052015A (en) * | 1956-11-20 | 1962-09-04 | Sylvania Electric Prod | High conductivity anode material |
| US3673452A (en) * | 1970-09-21 | 1972-06-27 | Ronald F Brennen | Spark plug |
| DE3036223A1 (en) * | 1979-10-22 | 1981-04-30 | Champion Spark Plug Co., Toledo, Ohio | Spark igniter |
| JPS56153676A (en) * | 1980-04-30 | 1981-11-27 | Nippon Denso Co | Ignition plug |
| US4764435A (en) * | 1985-06-17 | 1988-08-16 | Nippondenso Co., Ltd. | Metalizing or bonding composition for non-oxide ceramics |
| US4771209A (en) * | 1979-10-22 | 1988-09-13 | Champion Spark Plug Company | Spark igniter having precious metal ground electrode inserts |
| US20020074919A1 (en) * | 2000-12-15 | 2002-06-20 | Labarge William J. | Spark plug copper core alloy |
| WO2004084367A1 (en) * | 2003-03-18 | 2004-09-30 | Wärtsilä Finland Oy | Spark plug and method for producing it |
| US20070037039A1 (en) * | 2005-01-05 | 2007-02-15 | Symyx Technologies, Inc. | Platinum-copper-tungsten fuel cell catalyst |
| US20080308057A1 (en) * | 2007-06-18 | 2008-12-18 | Lykowski James D | Electrode for an Ignition Device |
| US20110146227A1 (en) * | 2009-12-23 | 2011-06-23 | Brendon Francis Mee | Apparatus and assembly for a spark igniter |
| DE102010055120A1 (en) * | 2010-12-18 | 2012-06-21 | Borgwarner Beru Systems Gmbh | Spark plug for motor vehicle, has inner conductor, insulator that surrounds inner conductor, spark plug body that surrounds insulator and two electrodes, which form ignition gap |
| US8901805B2 (en) * | 2008-08-28 | 2014-12-02 | Federal-Mogul Ignition Company | Ceramic electrode, ignition device therewith and methods of construction thereof |
| US9231381B2 (en) | 2008-08-28 | 2016-01-05 | Federal-Mogul Ignition Company | Ceramic electrode including a perovskite or spinel structure for an ignition device and method of manufacturing |
| DE102004026253B4 (en) | 2003-05-29 | 2018-06-28 | Denso Corporation | Spark plug and use of the spark plug |
-
1943
- 1943-06-22 US US491748A patent/US2391455A/en not_active Expired - Lifetime
Cited By (33)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2920223A (en) * | 1960-01-05 | Pxras | ||
| US2505150A (en) * | 1945-03-17 | 1950-04-25 | Gen Motors Corp | Spark plug with auxiliary gap |
| US2490214A (en) * | 1945-07-19 | 1949-12-06 | Mallory & Co Inc P R | Electrical contacting element |
| US2470033A (en) * | 1945-11-27 | 1949-05-10 | Mallory & Co Inc P R | Spark plug |
| US2642053A (en) * | 1948-07-16 | 1953-06-16 | Baker & Co Inc | Electrode for sparking plugs and their manufacture |
| US2514765A (en) * | 1948-11-15 | 1950-07-11 | Baker & Co Inc | Electrical resistance wire |
| US2819162A (en) * | 1954-09-29 | 1958-01-07 | Secon Metals Corp | Precious metal electrical resistance wires |
| US2737561A (en) * | 1955-10-10 | 1956-03-06 | Baker & Co Inc | Potentiometer |
| US3052015A (en) * | 1956-11-20 | 1962-09-04 | Sylvania Electric Prod | High conductivity anode material |
| US2927238A (en) * | 1958-10-06 | 1960-03-01 | Gen Motors Corp | Spark plug |
| US3673452A (en) * | 1970-09-21 | 1972-06-27 | Ronald F Brennen | Spark plug |
| DE3036223A1 (en) * | 1979-10-22 | 1981-04-30 | Champion Spark Plug Co., Toledo, Ohio | Spark igniter |
| US4771209A (en) * | 1979-10-22 | 1988-09-13 | Champion Spark Plug Company | Spark igniter having precious metal ground electrode inserts |
| JPS56153676A (en) * | 1980-04-30 | 1981-11-27 | Nippon Denso Co | Ignition plug |
| US4764435A (en) * | 1985-06-17 | 1988-08-16 | Nippondenso Co., Ltd. | Metalizing or bonding composition for non-oxide ceramics |
| US6677698B2 (en) * | 2000-12-15 | 2004-01-13 | Delphi Technologies, Inc. | Spark plug copper core alloy |
| US20020074919A1 (en) * | 2000-12-15 | 2002-06-20 | Labarge William J. | Spark plug copper core alloy |
| US7637793B2 (en) * | 2003-03-18 | 2009-12-29 | Wärtsilä Finland Oy | Spark plug and method for producing it |
| WO2004084367A1 (en) * | 2003-03-18 | 2004-09-30 | Wärtsilä Finland Oy | Spark plug and method for producing it |
| US20060103283A1 (en) * | 2003-03-18 | 2006-05-18 | Pertti Lintunen | Spark plug and method for producing it |
| DE102004026253B4 (en) | 2003-05-29 | 2018-06-28 | Denso Corporation | Spark plug and use of the spark plug |
| US20070037039A1 (en) * | 2005-01-05 | 2007-02-15 | Symyx Technologies, Inc. | Platinum-copper-tungsten fuel cell catalyst |
| US7422994B2 (en) * | 2005-01-05 | 2008-09-09 | Symyx Technologies, Inc. | Platinum-copper-tungsten fuel cell catalyst |
| US7707985B2 (en) * | 2007-06-18 | 2010-05-04 | Federal-Mogul World Wide, Inc. | Electrode for an ignition device |
| US20090107440A1 (en) * | 2007-06-18 | 2009-04-30 | Lykowski James D | Electrode For An Ignition Device |
| US20100175654A1 (en) * | 2007-06-18 | 2010-07-15 | Lykowski James D | Electrode for an Ignition Device |
| US7866294B2 (en) | 2007-06-18 | 2011-01-11 | Federal-Mogul Worldwide, Inc. | Electrode for an ignition device |
| US20080308057A1 (en) * | 2007-06-18 | 2008-12-18 | Lykowski James D | Electrode for an Ignition Device |
| US8901805B2 (en) * | 2008-08-28 | 2014-12-02 | Federal-Mogul Ignition Company | Ceramic electrode, ignition device therewith and methods of construction thereof |
| US9231381B2 (en) | 2008-08-28 | 2016-01-05 | Federal-Mogul Ignition Company | Ceramic electrode including a perovskite or spinel structure for an ignition device and method of manufacturing |
| US20110146227A1 (en) * | 2009-12-23 | 2011-06-23 | Brendon Francis Mee | Apparatus and assembly for a spark igniter |
| US8534041B2 (en) | 2009-12-23 | 2013-09-17 | Unison Industries, Llc | Apparatus and assembly for a spark igniter having tangential embedded pins |
| DE102010055120A1 (en) * | 2010-12-18 | 2012-06-21 | Borgwarner Beru Systems Gmbh | Spark plug for motor vehicle, has inner conductor, insulator that surrounds inner conductor, spark plug body that surrounds insulator and two electrodes, which form ignition gap |
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