GB2219626A - Partial surface discharge i.c. engine spark plug - Google Patents
Partial surface discharge i.c. engine spark plug Download PDFInfo
- Publication number
- GB2219626A GB2219626A GB8912635A GB8912635A GB2219626A GB 2219626 A GB2219626 A GB 2219626A GB 8912635 A GB8912635 A GB 8912635A GB 8912635 A GB8912635 A GB 8912635A GB 2219626 A GB2219626 A GB 2219626A
- Authority
- GB
- United Kingdom
- Prior art keywords
- spark plug
- central electrode
- annular element
- lugs
- insulating element
- 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
Links
- 229910052751 metal Inorganic materials 0.000 claims description 12
- 239000002184 metal Substances 0.000 claims description 12
- 238000002485 combustion reaction Methods 0.000 claims description 10
- 238000000034 method Methods 0.000 claims description 10
- 238000003466 welding Methods 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 239000012212 insulator Substances 0.000 claims description 3
- 238000007493 shaping process Methods 0.000 claims description 3
- 239000007769 metal material Substances 0.000 claims description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 5
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 229910052759 nickel Inorganic materials 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 229910000914 Mn alloy Inorganic materials 0.000 description 1
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- 229910000676 Si alloy Inorganic materials 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
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
- H01T13/52—Sparking plugs characterised by a discharge along a surface
-
- 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
Landscapes
- Spark Plugs (AREA)
Description
4 PARTIAL SURFACE DISCHARGE SPARK PLUG FOR AN INTERNAL COMBUSTION ENGINE
AND METHOD FOR 2 19 6 2 6 MANUFACTURING THE EARTH ELECTRODES OF SUCH A SPARK PLUG The present invention relates to a partial surface discharge spark plug for an internal combustion engine.
The invention relates specifically to a partial surface discharge spark plug comprising:
an external tubular metal body, an insulating element arranged inside the body and having one end which projects axially beyond the end of the body which during use is directed towards the combustion chamber, a central electrode which extends through the insulating element and projects axially beyond said end of the insulating element, and a plurality of earth electrodes connected to said 1.5 end of the body, angularly equidistant, and extending in the direction of the ends of the central electrode projecting from the insulator.
The novel features of the partial surface discharge spark plug according to the present invention are defined in the accompanying claims and in particular in Claim 1. The present invention relates, moreover, to a method for manufacturing the earth electrodes of a partial surface discharge spark plug of the aforementioned type. 25 The method according to the invention is characterized in that it comprises the operations of: obtaining, by means of blanking, an annular metal element having dimensions corresponding to those of the -abovementioned end of the external metal body and having 30 a plurality of coplanar integral lugs, radially projecting inwards, in angularly equidistant positions; shaping, by means of folding, the lugs of said annular element such that their free ends are arranged in a plane parallel to the plane of the annular element; the end surfaces of said free ends being equidistant from the axis of said annular element; 2 positioning the annular element so as to make contact with the abovementioned end of the body of the spark plug such that the end surfaces of the lugs of said annular element are facing and equidistant from the central electrode; and welding, preferably by means of a laser beam, the annular element to said external metal body of the spark plug.
Further characteristics and advantages of the inven- tion will emerge from the detailed description which follows, given with reference to the accompanying drawings provided purely by way of a non- limiting example, in which:
Figure 1 is a perspective view of a partial surface is discharge spark plug according to the present invention, Figure 2 is a partial view, in axial cross-section, of the end portion of the spark plug of Figure 1, Figure 3 is a plan view of an annular element with internal radial lugs, used according to the invention for forming the earth electrodes of the spark plug, Figure 4 is a sectioned view along the line IV-IV of Figure 3.
In Figure 1, 1 denotes in its entirety a partial surface discharge spark plug for an internal combustion engine according to the present invention. Such a spark plug comprises in a manner known per se an external tubular metal body 2, one end of which is threaded externally.
In a manner known per se, inside the body 2 there is arranged an element made of electrically.insulating material, typically ceramic material. This element has an end 3a which projects axially beyond the end of the body 2 which, during use, is directed towards the combustion chamber. As can be seen in particular in Figures 1 and 2, there extends through the insulating element 3 a central electrode 4 which in turn projects axially beyond the end 3a of said insulating element.
3 The central electrode 4 is connected in a -manner known per se and not shown to a high-voltage terminal indicated by 5 in Figure 1, projecting from the other end of the insulating element 3. 6 denotes an annular element made of metallic material welded to the end of the metal body 2, as can be seen in particular in Figure 2. This element may consist of a nickel-based alloy (for example an alloy containing Ni, Mg and Si) or a platinum- or copper-based alloy.
- Theannular element 6 has three integral lugs 7 which extend from its internal edge in angularly equi distant positions. As can be seen in particular in Figures 2 and 4, the lugs 7 of the metal annular element 6 have a substantially S-shaped profile and terminate with respective end surfaces 7a parallel to the longi- tudinal axis of this central electrode. Preferably, the end surfaces 7a of the lugs 7 lie on the same imaginary cylindrical surface indicated by 8 in Figure 3 and coaxial with the longitudinal axis of the electrode 4. 20 As stated before, the annular element 6 is welded onto the body 2 of the spark plug, preferably by means of a laser ray, in the manner schematically illustrated in Figure 2, where the laser beam is indicated by L. The lugs 7 of the annular element 6 form the earth electrodes of the spark plug.
Said earth electrodes 7 are shaped in particular such that their end surfaces 7a directed towards the central electrode 4 are intersected by the plane T transverse (Figure 2) to the axis of the spark plug, which plane is tangential to the end of the insulating element 3 from which the central electrode 4 emerges.
Advantageously, the optimum gap between the end surfaces of the earth electrodes 7 and the insulating element 3 is between 0.3 and 0.5 nillimetres and is preferably equal to 0.43 mm.
As can be seen in Figure 2, the end 3a of the insulating element 3 from which the central electrode 4 4 projects has internally a conical chamfer 9 (Figure 2) 1 which preferably has a depth in the axial direction of between 0.5 and 0.7 mm, and an angular opening of between 25 and 350, and preferably equal to 300.
Advantageously, the annular element 6 and the integral lugs 7 which form the earth electrodes are formed as a single piece by means of blanking from a small plate and by means of subsequent shaping by folding said lugs such that they assume the configuration shown in Figures 2 and 4. The annular element with the lugs thus shaped is then positioned so as to make contact with the end of the body 2 of the spark plug such that the end surfaces 7a of said earth electrodes are facing and equidistant from the central electrode 4 and from the end portion 3a of the insulating element 3. After which, as has already been said, the element 6 is welded to the body 2, preferably by using a laser beam or by means of electric welding or using a tungsten electrode.
Tests carried out by the inventors using spark plugs having the preferred dimensional parameters defined above and with earth electrodes consisting of a nickel, manganese and silicon alloy, have required starting voltages of less than 15 KV under any conditions of use.
The spark plugs manufactured in this manner thus enable the necessary starting voltage to be reduced considerably, said starting voltage having reached values as high as 20 KV in the case of the spark plugs known hitherto. 30 As a result of the tests carried out, it has also been possible to etablish that the spark plug inanufactured according to the invention is notable for its long working life. Obviously, the principle of the invention remaining the same., the embodiments and the constructional details may be greatly varied with respect to that which has been described and illustrated purely by way of a non- limiting example, without thereby departing from the scope of the present invention.
6
Claims (14)
1 Partial surface discharge spark plug for an internal combustion engine, comprising:
an external tubular metal body, an insulating element arranged inside the body and having one end which projects axially beyond the end of the body which during use is directed towards the combustion chamber, a central electrode which extends through the insulating element and projects axially beyond said end of the insulating element, and a plurality of earth electrodes connected to said end of the body, angularly equidistant, and extending in the direction towards the end of the central electrode which projects from the insulator; characterized in that the earth electrodes are shaped such that their end surfaces directed towards the central electrode are intersected by the plane, transverse to the axis of the spark plug, which is tangential to the end of the insulating element from which the central electrode projects.
2. Spark plug according to Claim 1, wherein the end portion of each earth electrode directed towards the central electrode is oriented perpendicularly to the axis of the central electrode and has an end surface parallel to said axis.
3. Spark plug according to Claim 2, wherein each earth electrode has a substantially S-shaped profile.
4. Spark plug according to any one of Claims 1 to 3, wherein the end of said insulating element from which the central electrode projects has at its end an internal conical chamfer.
7
5. Spark plug according to Claim 4, wherein said chamfer has a depth in the axial direction of between 0.5 and 0.7 mm, and an angular opening of between 250 and 350 and preferably equal to 300.
6. Spark plug according to any one of the preceding claims, wherein the earth electrodes consist of lugs of an annular element welded to the end of the external metal body.
7. Spark plug according to Claim 6, wherein said lugs and said ring are formed from a single piece of metallic material by means of blanking and folding.
8. Spark plug according to Claim 6 or 7, wherein said annular element is welded to the body by means of laserbeam welding or electric welding or TIG welding.
9. Method for manufacturing the earth electrodes of a partial surface discharge spark plug for an internal combustion engine the spark plug being of the type comprising:
an external tubular metal body, an insulating element arranged inside the body and having one end which projects axially beyond the end of the body which during use is directed towards the combustion chamber, a central electrode which extends through the insulating element and projects axially beyond said end of the insulating element, and a plurality of earth electrodes connected to said end of the body, angularly equidistant and extending in the direction of the end of the central electrode which projects from the insulator; the method being characterized by the fact that it comprises the operations of:
8 obtaining, by means of blanking, an annular metal element having dimensions corresponding to those of said end of the body and having a plurality of integral lug, radially projecting inwards, in angularly equidistant positions, shaping, by means of folding, the lugs of said annular element so that their free ends are arranged in a plane parallel to the plane of the annular element; the end surfaces of said free ends being equidistant from the axis of said annular element; positioning the annular element so as to make contact with the abovementioned end of the body of the spark plug in such a way that the end surfaces of said lugs of the annular element are facing and equidistant from the central electrode, and welding, preferably by means of a laser beam, the annular element to said metal body of the spark plug.
10. Method according to Claim 1, wherein said lugs of the annular element are shaped such that their end surfaces directed towards the central electrode are intersected by the plane, transverse to the axis of the spark plug, which is tangential to the end of the insulating element.
11. Method according to Claim 10, wherein the end portion of each lug of the annular element is oriented perpendicularly to the central electrode axis and has an end surface parallel to said axis.
12. Method according to Claim 11, wherein each of said lugs of the annular element has a substantially S-shaped profile.
9
13. A spark plug for an internal combustion engine substantially as hereinbefore described with reference to the accompanying drawings.
14. A method for manufacturing the earth electrodes of a spark plug substantially as hereinbefore described with reference to the accompanying drawings.
Published 1989 at The Patent Office, State House. 66'71 High Holbom. LondonWClR4TP. Ptirther copies maybe obtained from The Patent Office. Sales Branch, St Mary Cray, Orpington, Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent, Con. 1/87
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT8867555A IT8867555A0 (en) | 1988-06-10 | 1988-06-10 | MISURFACE DISCHARGE SPARK PLUG FOR INTERNAL COMBUSTION ENGINE AND PROCEDURE FOR MANUFACTURING THE GROUND ELECTRODES OF THIS SPARK PLUG |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8912635D0 GB8912635D0 (en) | 1989-07-19 |
| GB2219626A true GB2219626A (en) | 1989-12-13 |
| GB2219626B GB2219626B (en) | 1992-11-18 |
Family
ID=11303413
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8912635A Expired - Lifetime GB2219626B (en) | 1988-06-10 | 1989-06-02 | Partial surface discharge spark plug for an internal combustion engine and method for manufacturing the earth electrodes of such a spark plug |
Country Status (7)
| Country | Link |
|---|---|
| AR (1) | AR247047A1 (en) |
| BR (1) | BR8903024A (en) |
| DE (1) | DE3918466A1 (en) |
| ES (1) | ES2015698A6 (en) |
| FR (1) | FR2632785B1 (en) |
| GB (1) | GB2219626B (en) |
| IT (1) | IT8867555A0 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2323892A (en) * | 1997-04-03 | 1998-10-07 | Ford Motor Co | Ignition coil and spark plug assembly |
| JP2015129628A (en) * | 2013-12-26 | 2015-07-16 | ジョン ジンク カンパニー，エルエルシー | Improved high energy ignition spark igniter |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB656468A (en) * | 1947-05-23 | 1951-08-22 | Raymond Henri Devaux | Improvements in sparking plugs for internal combustion engines |
| GB906620A (en) * | 1960-05-12 | 1962-09-26 | Lodge Plugs Ltd | Improvements in or relating to sparking plugs for use in internal combustion engines |
| GB1373435A (en) * | 1971-02-13 | 1974-11-13 | Bosch Gmbh Robert | Sparking plugs |
| US4307316A (en) * | 1976-02-02 | 1981-12-22 | Mckechnie Ian C | Self cleaning spark plug |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2899585A (en) * | 1959-08-11 | dollenberg | ||
| DE2520622A1 (en) * | 1975-05-09 | 1976-11-18 | Bosch Gmbh Robert | SPARK PLUG FOR COMBUSTION MACHINERY |
| US4410309A (en) * | 1981-01-16 | 1983-10-18 | G. Rau Gmbh & Co. | Method of making a spark-plug center electrode |
| DE3600511A1 (en) * | 1985-05-31 | 1986-12-04 | Robert Bosch Gmbh, 7000 Stuttgart | SPARK PLUG FOR INTERNAL COMBUSTION ENGINES |
-
1988
- 1988-06-10 IT IT8867555A patent/IT8867555A0/en unknown
-
1989
- 1989-06-01 ES ES8901900A patent/ES2015698A6/en not_active Expired - Lifetime
- 1989-06-02 GB GB8912635A patent/GB2219626B/en not_active Expired - Lifetime
- 1989-06-06 DE DE3918466A patent/DE3918466A1/en not_active Ceased
- 1989-06-08 FR FR898907600A patent/FR2632785B1/en not_active Expired - Lifetime
- 1989-06-09 BR BR898903024A patent/BR8903024A/en not_active IP Right Cessation
- 1989-06-09 AR AR89314128A patent/AR247047A1/en active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB656468A (en) * | 1947-05-23 | 1951-08-22 | Raymond Henri Devaux | Improvements in sparking plugs for internal combustion engines |
| GB906620A (en) * | 1960-05-12 | 1962-09-26 | Lodge Plugs Ltd | Improvements in or relating to sparking plugs for use in internal combustion engines |
| GB1373435A (en) * | 1971-02-13 | 1974-11-13 | Bosch Gmbh Robert | Sparking plugs |
| US4307316A (en) * | 1976-02-02 | 1981-12-22 | Mckechnie Ian C | Self cleaning spark plug |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2323892A (en) * | 1997-04-03 | 1998-10-07 | Ford Motor Co | Ignition coil and spark plug assembly |
| JP2015129628A (en) * | 2013-12-26 | 2015-07-16 | ジョン ジンク カンパニー，エルエルシー | Improved high energy ignition spark igniter |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2219626B (en) | 1992-11-18 |
| AR247047A1 (en) | 1994-10-31 |
| FR2632785A1 (en) | 1989-12-15 |
| FR2632785B1 (en) | 1991-06-07 |
| DE3918466A1 (en) | 1989-12-14 |
| IT8867555A0 (en) | 1988-06-10 |
| GB8912635D0 (en) | 1989-07-19 |
| BR8903024A (en) | 1990-02-06 |
| ES2015698A6 (en) | 1990-09-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19970602 |