Patent US3911307A successfully refreshed from Google Patents.
US3911307A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Spark plug
Assignee: Toyota Motor Corp
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Filing: 1974-06-27
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Granted: 1975-10-07
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Expires: 1994-06-27
Abstract
Abstract A spark plug for electric ignition of the fuel-air mixture is disclosed, which spark plug is provided with a central positive electrode and an outer negative electrode facing the positive electrode via a sparking gap, and further comprises an electric insulator member for enclosing the sparking gap so that a discharge chamber is defined by the insulator member, said positive electrode and negative electrode, the discharge chamber being operable to produce plasma-like gas while discharging occurs between both said electrodes, and at least a nozzle is provided for said discharge chamber for enabling the plasma-like gas to jet into the fuel-air mixture. The spark plug can be adapted for use in a spark ignition type internal combustion engine.
Inventors
- 👤 Kenji Goto
- 👤 Daisaku Sawada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:02
CPC Classifications
F; F02; F02P; F02P19/00; F02P19/02; F02B; F02B1/00; F02B1/02; F02B1/04
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
212 words
A spark plug for electric ignition of a fuel-air mixture, of the type having an outer metal body including a cavity provided with a restricted opening at one end, a central electrode and insulating means for supporting the central electrode in the outer body with a tip of the electrode positioned within the cavity, the outer metal body serving as an outer electrode facing the central electrode via a sparking gap defined between the central electrode and the wall of the cavity, wherein the improvement comprises: an electric and heat insulator member lining substantially the entire inner wall of the cavity in the outer body from the tip of the central electrode to at least adjacent to the restricted opening for enclosing the sparking gap so that an insulated discharge chamber is defined by said insulator member in conjunction with said central electrode and said outer electrode, said insulated discharge chamber being small enough to be capable of maintaining a sufficiently high temperature to produce plasma-like gas when a spark discharge occurs between both said electrodes, and said restricted opening is at least not larger than the cross section of said discharge chamber to provide a throttling nozzle for enabling said plasma-like gas to jet at high velocity into said fuel-air mixture.
Claim 2
Dependent Claim
212 words
A spark plug for electric ignition of a fuel-air mixture, of the type having an outer metal body including a cavity provided with a restricted opening at one end, a central electrode and insulating means for supporting the central electrode in the outer body with a tip of the electrode positioned within the cavity, the outer metal body serving as an outer electrode facing the central electrode via a sparking gap defined between the central electrode and the wall of the cavity, wherein the improvement comprises: an electric and heat insulator member lining substantially the entire inner wall of the cavity in the outer body from the tip of the central electrode to at least adjacent to the restricted opening for enclosing the sparking gap so that an insulated discharge chamber is defined by said insulator member in conjunction with said central electrode and said outer electrode, said insulated discharge chamber being small enough to be capable of maintaining a sufficiently high temperature to produce plasma-like gas when a spark discharge occurs between both said electrodes, and said restricted opening is at least not larger than the cross section of said discharge chamber to provide a throttling nozzle for enabling said plasma-like gas to jet at high velocity into said fuel-air mixture.
Claim 3
Dependent Claim
49 words
A spark plug as claimed in claim 1, further comprising a second chamber formed in said outer metal body, said second chamber being connected to said discharge chamber through said nozzle and having a through hole to connect said second chamber with fuel-air mixture outside of said spark plug.
Claim 4
Dependent Claim
74 words
A spark plug as claimed in claim 1, wherein said discharge chamber is elongated, one end of said chamber being defined by the tip of said central electrode, the opposite end being defined by a portion of said outer metal body adjacent to said nozzle, and the side wall of said chamber being defined by said insulator member, the wall thickness of said insulator member being less than the length of said elongated chamber.
Claim 5
Dependent Claim
38 words
A spark plug as claimed in claim 1, wherein the cross-sectional area of the discharge chamber in a plane perpendicular to the axis of the central electrode is no greater than the cross-sectional area of said central electrode.
Claim 6
Dependent Claim
38 words
A spark plug as claimed in claim 1, wherein the cross-sectional area of the discharge chamber in a plane perpendicular to the axis of the central electrode is substantially equal to the cross-sectional area of said central electrode.
Claim 7
Dependent Claim
32 words
A spark plug as claimed in claim 5, wherein the insulator member lining the cavity in said outer metal body extends to the inner edge of the restricted opening from said cavity.
Claim 8
Dependent Claim
40 words
A spark plug as claimed in claim 1, further comprising at least one additional nozzle opening from said discharge chamber to provide additional high speed jets of plasma-like gas for contacting a larger amount of fuel-air mixture outside the chamber.
References Cited (Backward Citations)
US2687713A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-06 | 1979-04-07 | 1979-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-06 | 1983-04-07 | 1983-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-06 | 1987-04-07 | 1987-10-07 | $7700.00 | Window Closed / Lapsed |