GB2147660A - Centre electrodes for spark plugs - Google Patents

Centre electrodes for spark plugs Download PDF

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Publication number
GB2147660A
GB2147660A GB08424836A GB8424836A GB2147660A GB 2147660 A GB2147660 A GB 2147660A GB 08424836 A GB08424836 A GB 08424836A GB 8424836 A GB8424836 A GB 8424836A GB 2147660 A GB2147660 A GB 2147660A
Authority
GB
United Kingdom
Prior art keywords
jacket
sparking plug
resistant
plug centre
centre electrode
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.)
Granted
Application number
GB08424836A
Other versions
GB2147660B (en
GB8424836D0 (en
Inventor
Friedrich E Schneider
Dieter Stockel
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.)
Rau G GmbH and Co
Original Assignee
Rau G GmbH and Co
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 Rau G GmbH and Co filed Critical Rau G GmbH and Co
Publication of GB8424836D0 publication Critical patent/GB8424836D0/en
Publication of GB2147660A publication Critical patent/GB2147660A/en
Application granted granted Critical
Publication of GB2147660B publication Critical patent/GB2147660B/en
Expired legal-status Critical Current

Links

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

Abstract

The centre electrode comprises a tip member consisting of a highly corrosion-resistant and burn-off resistant material and a main electrode member 1. The tip member consists of a sleeve 4 made of a material such as nickel having good welding properties, adequate corrosion resistance and high mechanical strength and a core made of a highly corrosion-resistant and burn-off resistant material such as platinum. The sleeve is butt welded to the main electrode member which consists of a nickel part 2 and a copper core 3. <IMAGE>

Description

SPECIFICATION Sparking plug centre electrode This invention relates to a sparking plug centre electrode of the type having a wire-shaped ignition tip consisting of a highly corrosion resistant and burn-off resistant material mounted on a main electrode member.
Centre electrodes for sparking plugs used in combustion engines are known in a large number of forms. Of particular importance is the shape of the ignition tip requiring, on the one hand, high field compression for ensuring reliable ignition behaviour and, on the other hand, high burn-off resistance at high operating temperatures.
It is known from DE-PS 566633 to produce the electrodes of ignition plugs in composite material. In these plugs, components made of a material having a high vaporizing temperature, such as tungsten, are embedded in elongate form in a main component having a relatively low vaporizing temperature, such as silver. When the ignition tip burns off, the heavy vaporizable constituents are discharged from the more readily vaporizable embedded constituent; unevenness then develops at the ignition tip and this promotes high field compression and therefore favourable ignition behaviour. Such sparking plug centre electrodes do not, however, provide all of the required properties desirable in use, and furthermore the cost of production is not low, particularly when noble metals are used.
U.S. patent 2783409 describes a sparking plug centre electrode having a projecting ignition tip made of platinum. Although this material (which resists burn-off) results in favourable ignition be haviourwhen the specified wire-shaped form of ignition tip is used, the ignition tip cannot be produced in conjunction with the main electrode member on an economical basis. Instead an expensive production method is required for drilling out the main electrode member of nickel and the insertion of a rivet-like platinum pin, the shank of the rivet projecting as an ignition tip from the main electrode member, and the remaining cavity in said member being closed off by a copper pin.Furthermore, the inserted volume of noble metal is inefficiently utilised, since the rivet head, consisting of noble metal, is arranged in part within the main electrode member. Also, because of the differing thermal expansion of platinum and nickel, there arises the danger of the formation of a gap between the nickel main member and the platinum tip.
An available form of construction of sparking plug comprises a main electrode body to which is secured a thin wire-shaped ignition tip made of platinum.
The ignition tip and the main electrode body are contained in a ceramic protective jacket, which at the same time acts as a mechanical supporting element for the very thin platinum wire forming the ignition tip. Such form of sparking plug centre electrode is very costly to produce and, despite the thin wireshaped ignition tip, requires a relatively large amount of noble metal.
The present invention seeks to provide a sparking plug centre electrode of the initially stated type in such a way that a favourable sparking behaviour is achieved and simple low-cost mass-production becomes possible.
According to the invention there is provided a sparking plug centre electrode wherein a wireshaped ignition tip, consisting of a highly corrosionresistant and burn-off resistant material is provided on a main electrode member, characterised in that the ignition tip consists of a length of a jacket wire which projects freely from the main electrode member, said jacket wire comprising a jacket made of a material having good welding properties, adequate corrosion resistance and high mechanical strength, connected to a core of highly corrosion-resistant and burn-off resistant material.
Such a sparking plug centre electrode avoids the use of a sintered ceramic jacket and reduces the quantity of noble metal that is used. It can be produced in a simple manner and at low cost.
The core material of the jacket wire is advantageously metallically connected to the jacket material. This completely eliminates the danger of the formation of a gap.
In an expedient arrangement, the core material can be platinum or platinum alloy. Nickel or a nickel alloy may be advantageously used as the jacket material.
An advantageous method of production, in which the jacket wire can be butt-welded on to the main electrode member, can be used particularly when the jacket material consists of the same material as the main electrode member in the zone of attachment.
The features of the invention permit the production of a sparking plug centre electrode which provides favourable ignition properties because of the freely projecting portion of the jacket wire. When the jacket material burns off, the high corrosive resistant and burn-off resistant core material is exposed and forms a thin ignition tip of noble metal which results in appropriate field compression.
Since the jacket wire containing the noble metal projects freely at the main electrode member, the noble metal insert can be efficiently used during the service period.
The jacket material should have a high mechanical strength as compared with that of the core material so that undesirable deformation of the relatively thin ignition tip does not occur during setting of the electrode gap which is generally achieved by bending the main electrode towards the centre electrode, a distance piece being fitted between the two.
Furthermore, the high mechanical strength of the jacket material ensures that the wire portion in the zone of the weld is not excessively deformed during resistance welding.
The accompanying drawing illustrates diagrammatically and by way of example only part of a sparking plug having a centre electrode in accordance with the invention.
The main electrode member of the sparking plug is designated generally by the reference numeral 1, and consists of a shaped nickel part 2 with a copper insert 3. A 1.5 mm-long portion of a jacket wire 4 is butt-welded to the main electrode member and consists of a nickel jacket, which can be particularly efficiently welded to the shaped nickel part 2, and a core of pure platinum which, in practice, will have a diameter of approximately 0.2 mm. The thickness of the jacket wire is approximately 0.6 mm, whereas the main electrode member 1 has an outside diameter of approximately 2.5 mm. The thickening of the wire portion seen in the drawing is achieved by means of permissible slight upsetting during the welding on of the jacket wire 4.

Claims (9)

1. A sparking plug centre electrode wherein a wire-shaped ignition tip, consisting of a highly corrosion-resistant and burn-off resistant material is provided on a main electrode member, characterised in that the ignition tip consists of a length of a jacket wire which projects freely from the main electrode member, said jacket wire comprising a jacket made of a material having good welding properties, adequate corrosion resistance and high mechanical strength, connected to a core of highly corrosion-resistant and burn-off resistant material.
2. Asparking plug centre electrode according to claim 1 wherein the core material is metallically connected to the jacket material.
3. A sparking plug centre electrode according to either one of claims 1 or 2 wherein the core material is platinum.
4. A sparking plug centre electrode according to either one of claims 1 or 2 wherein the core material is a piatinum alloy.
5. A sparking plug centre electrode according to any one of claims 1 to 4 wherein the jacket material is nickel.
6. A sparking plug centre electrode according to any one of claims 1 to 4 wherein the jacket material is a nickel alloy.
7. A sparking plug centre electrode according to any one of the preceding claims wherein the jacket material is of the same material as the main electrode member, in the zone where the ignition tip is attached.
8. A sparking plug centre electrode according to any one of the preceding claims wherein the jacket wire is butt-welded on to the main electrode member.
9. A sparking plug centre electrode substantially as hereinbefore described with reference to the accompanying drawing.
GB08424836A 1983-10-03 1984-10-02 Centre electrodes for spark plugs Expired GB2147660B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19833335855 DE3335855A1 (en) 1983-10-03 1983-10-03 SPARK PLUG ELECTRODE

Publications (3)

Publication Number Publication Date
GB8424836D0 GB8424836D0 (en) 1984-11-07
GB2147660A true GB2147660A (en) 1985-05-15
GB2147660B GB2147660B (en) 1988-05-25

Family

ID=6210799

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08424836A Expired GB2147660B (en) 1983-10-03 1984-10-02 Centre electrodes for spark plugs

Country Status (5)

Country Link
BE (1) BE900726A (en)
DE (1) DE3335855A1 (en)
FR (1) FR2552947B1 (en)
GB (1) GB2147660B (en)
IT (2) IT8436112V0 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5866972A (en) * 1996-01-19 1999-02-02 Ngk Spark Plug Co., Ltd. Spark plug in use for an internal combustion engine

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2234920A (en) * 1989-08-11 1991-02-20 Ford Motor Co Forming an erosion resistant tip on an electrode
JPH03101086A (en) * 1989-09-14 1991-04-25 Ngk Spark Plug Co Ltd Spark plug for internal combustion engine

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB680374A (en) *
GB579269A (en) * 1944-05-02 1946-07-29 Mallory Metallurg Prod Ltd Improvements in or relating to sparking plugs and electrodes therefor
GB588074A (en) * 1944-01-29 1947-05-13 Mallory Metallurg Prod Ltd Improvements in and connected with sparking plugs
GB588197A (en) * 1944-02-01 1947-05-16 Mallory Metallurg Prod Ltd Improvements in and relating to sparking plugs
GB591420A (en) * 1944-03-14 1947-08-18 Mallory Metallurg Prod Ltd Improvements in or relating to spark gap or sparking plug electrodes
GB1180345A (en) * 1967-03-14 1970-02-04 Ford Motor Co Spark Plug having a Composite Gold or Gold Alloy Electrode and a process for its manufacture
GB1214240A (en) * 1968-09-03 1970-12-02 Champion Spark Plug Co Improvements in or relating to spark plugs
GB1437142A (en) * 1973-07-05 1976-05-26 Champion Spark Plug Co Spark plug centre electrode therefor and method of forming same
GB1463587A (en) * 1973-12-08 1977-02-02 Rau Fa G Spark plugs
GB1528514A (en) * 1975-02-27 1978-10-11 Rau Fa G Metallic composite material and method of producing the same

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE566633C (en) * 1932-12-22 Robert Bosch Akt Ges Spark plug with electrodes that consist of a mixture of high and low evaporation temperature components
US2344597A (en) * 1941-03-18 1944-03-21 Johnson Matthey Co Ltd Electrode for sparking plugs
US2391457A (en) * 1944-02-01 1945-12-25 Mallory & Co Inc P R Spark plug electrode construction
US2783409A (en) * 1952-03-31 1957-02-26 Gen Motors Corp Spark plug electrode and process for making same
GB764831A (en) * 1954-04-07 1957-01-02 K L G Sparking Plugs Ltd Improvements in or relating to spark plugs and to electrodes for spark plugs
DE1908418U (en) * 1964-06-05 1965-01-14 Bosch Gmbh Robert SPARK PLUG WITH PLATINUM METAL ELECTRODE.
DE1215834B (en) * 1964-06-13 1966-05-05 Bosch Gmbh Robert Method for welding ignition tips made of high quality metal, in particular platinum
US3984717A (en) * 1973-08-30 1976-10-05 Chrysler Corporation Spark plug
DE2444509A1 (en) * 1974-09-18 1976-04-08 Bosch Gmbh Robert Centre electrode of sparking plug for IC engine - consists of bundle of nickel alloy based fibres encased in nickel alloy sheath

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB680374A (en) *
GB588074A (en) * 1944-01-29 1947-05-13 Mallory Metallurg Prod Ltd Improvements in and connected with sparking plugs
GB588197A (en) * 1944-02-01 1947-05-16 Mallory Metallurg Prod Ltd Improvements in and relating to sparking plugs
GB591420A (en) * 1944-03-14 1947-08-18 Mallory Metallurg Prod Ltd Improvements in or relating to spark gap or sparking plug electrodes
GB579269A (en) * 1944-05-02 1946-07-29 Mallory Metallurg Prod Ltd Improvements in or relating to sparking plugs and electrodes therefor
GB1180345A (en) * 1967-03-14 1970-02-04 Ford Motor Co Spark Plug having a Composite Gold or Gold Alloy Electrode and a process for its manufacture
GB1214240A (en) * 1968-09-03 1970-12-02 Champion Spark Plug Co Improvements in or relating to spark plugs
GB1437142A (en) * 1973-07-05 1976-05-26 Champion Spark Plug Co Spark plug centre electrode therefor and method of forming same
GB1463587A (en) * 1973-12-08 1977-02-02 Rau Fa G Spark plugs
GB1528514A (en) * 1975-02-27 1978-10-11 Rau Fa G Metallic composite material and method of producing the same

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5866972A (en) * 1996-01-19 1999-02-02 Ngk Spark Plug Co., Ltd. Spark plug in use for an internal combustion engine

Also Published As

Publication number Publication date
BE900726A (en) 1985-02-01
IT8448936A0 (en) 1984-10-02
IT1178012B (en) 1987-09-03
IT8448936A1 (en) 1986-04-02
DE3335855A1 (en) 1985-04-11
FR2552947B1 (en) 1988-03-18
DE3335855C2 (en) 1991-05-16
FR2552947A1 (en) 1985-04-05
IT8436112V0 (en) 1984-10-02
GB2147660B (en) 1988-05-25
GB8424836D0 (en) 1984-11-07

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19921002