Patent US4162631A successfully refreshed from Google Patents.
US4162631A
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Rare earth or yttrium, transition metal oxide thermistors
Assignee: Ford Motor Co
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Filing: 1977-12-05
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Granted: 1979-07-31
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Expires: 1997-12-05
Abstract
Abstract Thermistors comprising transition metal such as iron, rare earth of the lanthanide series or yttrium, and oxygen exhibit sufficient independence to variation in oxygen partial pressure over a range of exhaust gas conditions of internal combustion engines as to make them particularly suitable for temperature compensation of oxygen sensors such as those derived from titania as well as temperature sensing in other oxygen varying environments.
Inventors
- 👤 Eleftherios M. Logothetis
- 👤 Kamlakar R. Laud
- 👤 John K. Park
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:41
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/50; G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/12; H; H01; H01C; H01C7/00; H01C7/04; H01C7/042; H01C7/043
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
61 words
A method of sensing temperature in an oxygen varying environment that contains combustion engine exhaust gas which comprises exposing to the environment a thermistor composition comprising (a) transition metal comprising iron, (b) one or more rare earth of the lanthanide series or yttrium and (c) oxygen in a respective molar ratio of the ions of about 1:1:3 and detecting its resistance.
Claim 2
Independent Claim
61 words
A method of sensing temperature in an oxygen varying environment that contains combustion engine exhaust gas which comprises exposing to the environment a thermistor composition comprising (a) transition metal comprising iron, (b) one or more rare earth of the lanthanide series or yttrium and (c) oxygen in a respective molar ratio of the ions of about 1:1:3 and detecting its resistance.
Claim 3
Dependent Claim
13 words
A method in accordance with claim 1, wherein the rare earth comprises praseodymium.
Claim 4
Dependent Claim
32 words
A method in accordance with claim 1, wherein the thermistor composition comprises a compound having a formula corresponding to RFeO 3 wherein R is rare earth of the lanthanide series or yttrium.
Claim 5
Dependent Claim
23 words
A method in accordance with claim 3, wherein the compound comprises a single phase having a density higher than about 60% of theoretical.
Claim 6
Dependent Claim
13 words
A method in accordance with claim 4, wherein the rare earth comprises praseodymium.
Claim 7
Dependent Claim
45 words
In an automotive feedback fuel control system that utilizes an oxygen sensor comprising titania and a thermistor in series electrical connection therewith for temperature compensation of the oxygen sensor, the improvement wherein the thermistor comprises a compound having a formula corresponding to PrFeO 3 .
Claim 8
Dependent Claim
45 words
In an automotive feedback fuel control system that utilizes an oxygen sensor comprising titania and a thermistor in series electrical connection therewith for temperature compensation of the oxygen sensor, the improvement wherein the thermistor comprises a compound having a formula corresponding to PrFeO 3 .
Claim 9
Independent Claim
61 words
A method of sensing temperature in an oxygen varying environment which comprises exposing to the environment a thermistor composition comprising a compound having a formula corresponding to RFeO 3 wherein R is a rare earth of the lanthanide series or yttrium, the thermistor composition being in electrical communication with an oxygen sensor comprising titania, and detecting resistance of the thermistor composition.
Claim 10
Independent Claim
61 words
A method of sensing temperature in an oxygen varying environment which comprises exposing to the environment a thermistor composition comprising a compound having a formula corresponding to RFeO 3 wherein R is a rare earth of the lanthanide series or yttrium, the thermistor composition being in electrical communication with an oxygen sensor comprising titania, and detecting resistance of the thermistor composition.
Claim 11
Dependent Claim
22 words
A method in accordance with claim 7 wherein the thermistor composition comprises a compound having a formula corresponding to PrFeO 3 .
Claim 12
Dependent Claim
22 words
A method in accordance with claim 7 wherein the thermistor composition comprises a compound having a formula corresponding to PrFeO 3 .
Claim 13
Independent Claim
65 words
A method of sensing temperature in an oxygen varying environment that contains combustion engine exhaust gas which comprises exposing to the environment a thermistor composition comprising a compound having a formula corresponding to RFeO 3 wherein R is a rare earth of the lanthanide series or yttrium, the thermistor composition being used in combination with an oxygen sensor and detecting resistance of the thermistor composition.
Claim 14
Independent Claim
65 words
A method of sensing temperature in an oxygen varying environment that contains combustion engine exhaust gas which comprises exposing to the environment a thermistor composition comprising a compound having a formula corresponding to RFeO 3 wherein R is a rare earth of the lanthanide series or yttrium, the thermistor composition being used in combination with an oxygen sensor and detecting resistance of the thermistor composition.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-07-30 | 1983-01-29 | 1983-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-07-30 | 1987-01-29 | 1987-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-07-30 | 1991-01-29 | 1991-07-31 | $7700.00 | Window Closed / Lapsed |