Patent US4265724A successfully refreshed from Google Patents.
US4265724A
Expired / Lapsed
US
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Electrochemical sensor, particularly oxygen sensor to determine exhaust gas composition from automotive internal combustion engines
Assignee: Robert Bosch GmbH
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Filing: 1979-07-05
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Granted: 1981-05-05
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Expires: 1999-07-05
Abstract
Abstract To improve adhesion of a porous cover layer over a platinum or platinum-rhodium electrode layer on a solid electrolyte body, for example of stabilized zirconium dioxide, the electrode layer is applied in form of interrupted, adjacent strips leaving gaps exposing the solid electrolyte body therebeneath. The porous cover layer will adhere well to the solid electrolyte body, thus protecting both the electrode and the cover layer against flaking off under high-temperature and temperature variation conditions. The sensitivity can be improved by interposing a layer of ceramic mixed with platinum or a platinum rhodium between the solid electrolyte body and at least some of the electrode strips, the adhesion of the porous cover layer over the interposed thick-film layer, where exposed between the portions of the electrode on the solid electrolyte body being sufficient for the intended purpose.
Inventors
- 👤 Wolf-Dieter Haecker
- 👤 Karl-Hermann Friese
- 👤 Bernhard Topp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 09:15
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/403; G01N27/406; G01N27/407; G01N27/4075
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
191 words
Electrochemical sensor, particularly to determine oxygen content in the exhaust gases from automotive internal combustion engines comprising a solid electrolyte body (1) having a sensing portion (1'); a thin-film electrode (3, 3') on said electrolyte body of a material which catalyzes the gas equilibrium of gases to which the sensor is exposed; and a porous cover layer (6) wherein, in accordance with the invention, the thin-film electrode (3, 4) consists of a material consisting of at least one: platinum; platinum alloy; platinum-rhodium and is located on and in direct contact with the solid electrolyte body (1) in form of partial, spacially interrupted and electrically interconnected covering portions thereon, leaving gaps (3) between the direct contact of said covering portions of thin-film electrode and on the solid electrolyte body (1); and the porous cover layer (6) comprises at leasat one: a ceramic oxide; a mixture of several ceramic oxides and covers the entire sensing portion including the thin-film electrode material, and the solid electrolyte body in the region of the gaps (5) between the electrodes, to provide for direct contact of the porous cover layer (6) with the solid electrolyte body (1).
Claim 2
Dependent Claim
191 words
Electrochemical sensor, particularly to determine oxygen content in the exhaust gases from automotive internal combustion engines comprising a solid electrolyte body (1) having a sensing portion (1'); a thin-film electrode (3, 3') on said electrolyte body of a material which catalyzes the gas equilibrium of gases to which the sensor is exposed; and a porous cover layer (6) wherein, in accordance with the invention, the thin-film electrode (3, 4) consists of a material consisting of at least one: platinum; platinum alloy; platinum-rhodium and is located on and in direct contact with the solid electrolyte body (1) in form of partial, spacially interrupted and electrically interconnected covering portions thereon, leaving gaps (3) between the direct contact of said covering portions of thin-film electrode and on the solid electrolyte body (1); and the porous cover layer (6) comprises at leasat one: a ceramic oxide; a mixture of several ceramic oxides and covers the entire sensing portion including the thin-film electrode material, and the solid electrolyte body in the region of the gaps (5) between the electrodes, to provide for direct contact of the porous cover layer (6) with the solid electrolyte body (1).
Claim 3
Dependent Claim
11 words
Sensor according to claim 1, wherein the interrupted portions are strip-like.
Claim 4
Dependent Claim
41 words
Sensor according to claim 1, wherein (FIGS. 1, 2) the thin-film electrode (3, 3') comprises a comb-like structure, the interrupted portions are strip-like elements forming the tines of the comb, and a continuous connecting portion interconnecting the tines of the comb.
Claim 5
Dependent Claim
41 words
Sensor according to claim 3, wherein the solid electrolyte body is a closed tube, and the interconnecting portion is positioned near the open end of the closed tube, the tines extending essentially longitudinally along the tube towards the closed end thereof.
Claim 6
Dependent Claim
15 words
Sensor according to claim 1, wherein the solid electrolyte body (1) comprises stabilized zirconium dioxide.
Claim 7
Dependent Claim
20 words
Sensor according to claim 1, wherein the porous cover layer (6) comprises at least one of: aluminum oxide; manganese-aluminum spinel.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-05-04 | 1984-11-03 | 1985-05-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-05-04 | 1988-11-03 | 1989-05-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-05-04 | 1992-11-03 | 1993-05-05 | $7700.00 | Window Closed / Lapsed |