US5160598A
Expired / Lapsed
US
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Oxygen sensor for air-fuel ratio control having a protective layer including an oxygen storage material
Assignee: Niterra Co Ltd
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Filing: 1990-02-14
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Granted: 1992-11-03
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Expires: 2010-02-14
Abstract
Abstract Oxygen sensor for air-fuel ratio control is provided with a sensor element having an oxygen ion-conductive main body and electrodes on both sides thereof, and at least one porous protective layer covering the electrode on the exhaust gas side. The protective layer includes an oxygen storage component OSC without copresence of a noble metal catalyst. The protective layer is intermeshingly connected to the main body via spherical protrusions of the main body. Double-layered protective layer structure includes OSC noncontaining layer (optionally containing catalyst) and OSC containing layer, as inner and outer protective layer or vice versa. OSC containing layer is formed by impregnation with OSC-solution through immersing the respective porous protective layer, or by cosintering the OSC containing green coating layer. By impregnation 0.2 -8 wt %, or by cosintering 0.2-30 wt %, of OSC metal element is containable. The outer protective layer is thinner and more porous than the inner protective layer. Any of the protective layers can be formed by flame spraying.
Inventors
- 👤 Toshiki Sawada
- 👤 Masaru Yamano
- 👤 Kazuo Taguchi
- 👤 Takao Kojima
- 👤 Hiroyuki Ishiguro
- 👤 Masahiko Yamada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 13:26
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/403; G01N27/406; G01N27/407; G01N27/4075; G01N27/4077; G01N27/4078
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
180 words
An oxygen sensor for air-fuel ratio control, comprising a sensor element having an oxygen-ion conductive main body and electrodes disposed on both sides of the main body, and protective layers covering the electrode on the side of the sensor element assigned to be exposed to a gas to be measured wherein the protective layers comprise a first protective layer and a second protective layer, each made of a heat-resistant metal oxide provided on the side of the sensor element assigned to be exposed to the gas to be measured, the first protective layer being disposed closer to the electrode than the second protective layer, wherein either one of the first and second protective layers includes a noble metal catalyst, wherein the other one of the first and second protective layers includes an oxygen storage component without substantial copresence of the noble metal catalyst, and wherein the main body of the sensor element comprises a base portion and a portion with a plurality of spherical protrusions, the first protective layer being intermeshingly connected to the base portion via the spherical protrusions.
Claim 2
Dependent Claim
180 words
An oxygen sensor for air-fuel ratio control, comprising a sensor element having an oxygen-ion conductive main body and electrodes disposed on both sides of the main body, and protective layers covering the electrode on the side of the sensor element assigned to be exposed to a gas to be measured wherein the protective layers comprise a first protective layer and a second protective layer, each made of a heat-resistant metal oxide provided on the side of the sensor element assigned to be exposed to the gas to be measured, the first protective layer being disposed closer to the electrode than the second protective layer, wherein either one of the first and second protective layers includes a noble metal catalyst, wherein the other one of the first and second protective layers includes an oxygen storage component without substantial copresence of the noble metal catalyst, and wherein the main body of the sensor element comprises a base portion and a portion with a plurality of spherical protrusions, the first protective layer being intermeshingly connected to the base portion via the spherical protrusions.
Claim 3
Dependent Claim
20 words
The oxygen sensor as defined in claim 1, in which the oxygen storage component is a nonstoichiometric oxide of metal.
Claim 4
Dependent Claim
25 words
The oxygen sensor as defined in claim 1, in which the oxygen storage component is an oxide of at least one of cerium and vanadium.
Claim 5
Dependent Claim
43 words
The oxygen sensor as defined in claim 1, in which the oxygen storage component is present in an amount of 0.2-30 wt % in terms of metal element relative to the heat-resistant metal oxide of the protective layer containing said oxygen storage component.
Claim 6
Dependent Claim
48 words
The oxygen sensor as defined in claim 1, in which the oxygen storage component is present in an amount of 0.2-8 wt % in terms of metal element of the oxygen storage component relative to the heat-resistant metal oxide of the protective layer containing said oxygen storage component.
Claim 7
Dependent Claim
35 words
The oxygen sensor as defined in claim 1, in which the oxygen storage component is present in an area extending over at least a half of the entire protective layer containing said oxygen storage component.
Claim 8
Dependent Claim
23 words
The oxygen sensor as defined in claim 1, in which the spherical protrusions are made of the same material as the sensor element.
Claim 9
Dependent Claim
23 words
The oxygen sensor as defined in claim 7, in which the sensor element is formed of a solid electrolyte material or semiconductive material.
Claim 10
Dependent Claim
26 words
The oxygen sensor as defined in claim 1, in which the spherical protrusions are made of spherical particles which have an average size of 40-100 μm.
Claim 11
Dependent Claim
31 words
The oxygen sensor as defined in any one of claims 1, 3, 4 or 9, in which the protective layer has a porosity of 5-20% and a thickness of 30-200 μm.
Claim 12
Dependent Claim
27 words
The oxygen sensor as defined in claim 1, in which the heat-resistant metal oxide of the protective layers is formed mainly of MgO.Al 2 O 3 spinel.
Claim 13
Dependent Claim
135 words
An oxygen sensor for air-fuel ratio control, provided with a sensor element having an oxygen ion-conductive main body of the sensor element and electrodes disposed on both the sides of the main body, and at least a protective layer covering the electrode on a side assigned to be exposed to a gas to be measured characterized in that a first protective layer and a second protective layer, each made of a heat-resistant metal oxide, are provided on the side assigned to be exposed to the gas to be measured of the sensor element, the first protective layer being disposed closer to the electrode than the second, that the first protective layer includes a noble metal catalyst, and that the second protective layer includes an oxygen storage component without substantial copresence of the noble metal catalyst.
Claim 14
Dependent Claim
135 words
An oxygen sensor for air-fuel ratio control, provided with a sensor element having an oxygen ion-conductive main body of the sensor element and electrodes disposed on both the sides of the main body, and at least a protective layer covering the electrode on a side assigned to be exposed to a gas to be measured characterized in that a first protective layer and a second protective layer, each made of a heat-resistant metal oxide, are provided on the side assigned to be exposed to the gas to be measured of the sensor element, the first protective layer being disposed closer to the electrode than the second, that the first protective layer includes a noble metal catalyst, and that the second protective layer includes an oxygen storage component without substantial copresence of the noble metal catalyst.
Claim 15
Dependent Claim
25 words
The oxygen sensor as defined in claim 12, in which the first protective layer has a porosity of 5-20% and a thickness of 30-200 μm.
Claim 16
Dependent Claim
34 words
The oxygen sensor as defined in claim 12, in which the noble metal catalyst is carried in an amount of 0.01-5 wt % relative to the heat-resistant metal oxide constituting the first protective layer.
Claim 17
Dependent Claim
29 words
The oxygen sensor as defined in claim 12, in which the noble metal catalyst is a catalyst comprised mainly of Pt or that comprised mainly of Rh and Pd.
Claim 18
Dependent Claim
28 words
The oxygen sensor as defined in claim 12, in which the heat-resistant metal oxide in the first protective layer is at least one of stoichiometric and nonstoichiometric compound.
Claim 19
Dependent Claim
18 words
The oxygen sensor as defined in claim 12, in which the oxygen storage component is a nonstoichiometric oxide.
Claim 20
Dependent Claim
44 words
The oxygen sensor as defined in claim 12, in which the oxygen storage component is present in an amount of 0.2-30 wt % in terms of metal element of the oxygen storage component relative to the heat-resistant metal oxide constituting the second protective layer.
Claim 21
Dependent Claim
44 words
The oxygen sensor as defined in claim 12, in which the oxygen storage component is present is an amount of 0.2-8 wt % in terms of metal element of the oxygen storage component relative to the heat-resistant metal oxide constituting the second protective layer.
Claim 22
Dependent Claim
35 words
The oxygen sensor as defined in claim 12, in which the oxygen storage component is included in an area extending over at least a half of the entire surface area of the second protective layer.
Claim 23
Dependent Claim
36 words
The oxygen sensor as defined in claim 12, in which the second protective layer has a porosity greater than that of the first protective layer and a thickness thinner than that of the first protective layer.
Claim 24
Dependent Claim
20 words
The oxygen sensor as defined in claim 12, in which the second protective layer is formed of heat-resistant metal oxide.
Claim 25
Dependent Claim
133 words
An oxygen sensor for air-fuel ratio control, comprising a sensor element having an oxygen-ion conductive main body and electrodes disposed on both sides of the main body, and protective layers covering the electrode on the side of the sensor element assigned to be exposed to a gas to be measured wherein the protective layers comprise a first protective layer and a second protective layer, each made of a heat-resistant metal oxide provided on the side of the sensor element assigned to be exposed to the gas to be measured, the first protective layer being disposed closer to the electrode than the second protective layer, wherein the second protective layer includes a noble metal catalyst, and wherein the first protective layer includes an oxygen storage component without substantial copresence of the noble metal catalyst.
Claim 26
Dependent Claim
133 words
An oxygen sensor for air-fuel ratio control, comprising a sensor element having an oxygen-ion conductive main body and electrodes disposed on both sides of the main body, and protective layers covering the electrode on the side of the sensor element assigned to be exposed to a gas to be measured wherein the protective layers comprise a first protective layer and a second protective layer, each made of a heat-resistant metal oxide provided on the side of the sensor element assigned to be exposed to the gas to be measured, the first protective layer being disposed closer to the electrode than the second protective layer, wherein the second protective layer includes a noble metal catalyst, and wherein the first protective layer includes an oxygen storage component without substantial copresence of the noble metal catalyst.
Claim 27
Dependent Claim
44 words
The oxygen sensor as defined in claim 23, in which the oxygen storage component of the first protective layer is present in an amount of 0.2-30 wt % in terms of metal element of the oxygen storage component relative to the heat-resistant metal oxide.
Claim 28
Dependent Claim
28 words
The oxygen sensor as defined in claim 23, in which the oxygen storage component is at least one selected from oxides of rare earth elements and vanadium oxide.
Claim 29
Dependent Claim
21 words
The oxygen sensor as defined in claim 23, in which the oxygen storage component is an oxide of Ce and V.
Claim 30
Dependent Claim
25 words
The oxygen sensor as defined in claim 23, in which the second protective layer has a porosity greater than that of the first protective layer.
Claim 31
Dependent Claim
19 words
The oxygen sensor as defined in claim 23, in which the first protective layer has a porosity of 5-20%.
Claim 32
Dependent Claim
19 words
The oxygen sensor as defined in claim 23, in which the second protective layer has a porosity of 30-50%.
Claim 33
Dependent Claim
21 words
The oxygen sensor as defined in claim 23, in which the second protective layer is thinner than the first protective layer.
Claim 34
Dependent Claim
17 words
The oxygen sensor as defined in claim 23, in which the first protective layer is 30-200 μm.
Claim 35
Dependent Claim
17 words
The oxygen sensor as defined in claim 23, in which the second protective layer is 10-50 μm.
Claim 36
Dependent Claim
26 words
The oxygen sensor as defined in claim 23, in which the second protective layer includes a noble metal catalyst in an amount of 0.01-5 wt %.
Claim 37
Dependent Claim
30 words
The oxygen sensor as defined in claim 23, in which the oxygen storage component is contained in an area extending over at least a half of the first protective layer.
Claim 38
Dependent Claim
38 words
The oxygen sensor as defined in claim 23, in which the heat-resistant metal oxide of the first protective layer is comprised mainly of at least one selected from the group consisting of alumina, spinel, magnesia, berillia, and zirconia.
Claim 39
Dependent Claim
27 words
The oxygen sensor as defined in claim 23, in which the heat-resistant metal oxide of the second protective layer is at least one of stoichiometric and nonstoichiometric.
Claim 40
Dependent Claim
30 words
The oxygen sensor as defined in claim 23, in which the nonstoichiometric oxide of the second protective layer is at least one of TiO 2-x (x=0.02-0.3) and oxide of Ni.
Claim 41
Dependent Claim
42 words
The oxygen sensor as defined in claim 12 or 23, in which the main body of the sensor element comprises a base portion and a spherically-protruded portion, the first protective layer being intermeshingly connected to the base portion via the spherically-protruded portion.
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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) | 1995-11-03 | 1996-05-04 | 1996-11-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-11-03 | 2000-05-04 | 2000-11-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-11-03 | 2004-05-04 | 2004-11-03 | $7700.00 | Window Closed / Lapsed |