Patent USH427H successfully refreshed from Google Patents.
USH427H
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US
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Air/fuel ratio detector
Assignee: Niterra Co Ltd
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Filing: 1984-12-17
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Granted: 1988-02-02
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Expires: 2004-12-17
Abstract
Abstract An air/fuel ratio detector comprising a pump and an electrochemical cell in which both the pump and electrochemical cell comprise an oxygen ion conductive solid electrolyte sandwiched between porous electrodes. One of the elements has an insulating substrate formed on a portion of the electrolyte. Over the substrate is formed a layer of semiconducting metal oxide. The cell and pump face each other with the cell providing an EMF and the pump being pumped by a pump current. The size of the resistance of the metal oxide layer indicates whether the air/fuel mixture is rich or lean relative to a stoichiometric mixture and the values of the EMF and pump current indicate the deviation from stoichiometry.
Inventors
- 👤 Shintaro Hirate
- 👤 Tetsusyo Yamada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:39
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/416; G01N27/417; G01N27/403; G01N27/406; G01N27/4065
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
124 words
An air/fuel ratio detector comprising a solid electrolyte electrochemical cell element actuated by an oxygen concentration difference and a solid electrolyte oxygen pump element, each element being in the form of an oxygen ion conductive solid electrolyte having a porous electrode formed on both sides, and further comprising a semiconducting metal oxide layer, said cell element and said pump element and said metal oxide layer being disposed a small distance part, said electrochemical cell and said pump element providing a first electrical signal varying with the air/fuel ratio over a first range, said metal oxide providing a second electrical signal varying, more sharply than said first electrical signal, with the air/fuel ratio over a second range included within and narrower than said first range.
Claim 2
Dependent Claim
124 words
An air/fuel ratio detector comprising a solid electrolyte electrochemical cell element actuated by an oxygen concentration difference and a solid electrolyte oxygen pump element, each element being in the form of an oxygen ion conductive solid electrolyte having a porous electrode formed on both sides, and further comprising a semiconducting metal oxide layer, said cell element and said pump element and said metal oxide layer being disposed a small distance part, said electrochemical cell and said pump element providing a first electrical signal varying with the air/fuel ratio over a first range, said metal oxide providing a second electrical signal varying, more sharply than said first electrical signal, with the air/fuel ratio over a second range included within and narrower than said first range.
Claim 3
Dependent Claim
155 words
An air/fuel ratio detector comprising a solid electrolyte electrochemical cell element actuated by an oxygen concentration difference and a solid electrolyte oxygen pump element, each element being in the form of an oxygen ion conductive solid electrolyte having a porous electrode formed on both sides, at least one of said elements having an electrically insulating substrate formed on one side except for the area where said porous electrode is provided, said insulating substrate having a semiconducting metal oxide layer formed on its surface, said cell element and said pump element being disposed to face each other a small distance apart, said electrochemical cell and said pump element providing a first electrical signal varying with the air/fuel ratio over a first range, said semiconducting metal oxide layer providing a second electrical signal varying, more sharply than said first electrical signal, with the air/fuel ratio over a second range included within and narrower than said first range.
Claim 4
Dependent Claim
155 words
An air/fuel ratio detector comprising a solid electrolyte electrochemical cell element actuated by an oxygen concentration difference and a solid electrolyte oxygen pump element, each element being in the form of an oxygen ion conductive solid electrolyte having a porous electrode formed on both sides, at least one of said elements having an electrically insulating substrate formed on one side except for the area where said porous electrode is provided, said insulating substrate having a semiconducting metal oxide layer formed on its surface, said cell element and said pump element being disposed to face each other a small distance apart, said electrochemical cell and said pump element providing a first electrical signal varying with the air/fuel ratio over a first range, said semiconducting metal oxide layer providing a second electrical signal varying, more sharply than said first electrical signal, with the air/fuel ratio over a second range included within and narrower than said first range.
Claim 5
Dependent Claim
37 words
A detector as recited in claim 2, wherein said first electrical signal is derived from a pump current of said pump element and further comprising means for holding an electromotive force of said cell element substantially constant.
Claim 6
Dependent Claim
115 words
An air/fuel ratio detector comprising a solid electrolyte electrochemical cell element actuated by an oxygen concentration difference, a solid electrolyte oxygen pump element, and an oxygen reference element having a semiconducting metal oxide layer formed on the surface of an electrically insulating member, said cell element and said pump element being disposed to face each other a small distance apart, said electrochemical cell and said pump element providing a first electrical signal varying with the air/fuel ratio over a first range, said semiconducting metal oxide layer providing a second electrical signal varying, more sharply than said first electrical signal, with the air/fuel ratio over a second range included within and narrower than said first range.
Claim 7
Dependent Claim
115 words
An air/fuel ratio detector comprising a solid electrolyte electrochemical cell element actuated by an oxygen concentration difference, a solid electrolyte oxygen pump element, and an oxygen reference element having a semiconducting metal oxide layer formed on the surface of an electrically insulating member, said cell element and said pump element being disposed to face each other a small distance apart, said electrochemical cell and said pump element providing a first electrical signal varying with the air/fuel ratio over a first range, said semiconducting metal oxide layer providing a second electrical signal varying, more sharply than said first electrical signal, with the air/fuel ratio over a second range included within and narrower than said first range.
Claim 8
Dependent Claim
37 words
A detector as recited in claim 4, wherein said first electrical signal is derived from a pump current flowing through said element and further comprising means for holding an electromotive force of said cell element substantially constant.
Claim 9
Independent Claim
141 words
A method for measuring air/fuel ratio, comprising the steps of: placing within a chamber containing an air/fuel mixture to be measured a solid electrolyte electrochemical cell element actuated by an oxygen concentration difference and a solid electrolyte pump element, each element being in the form of an oxygen ion conductive solid electrolyte having a porous electrode formed on each side; placing within said chamber a semiconducting metal oxide layer, said metal oxide, said cell element and said pump element being disposed a small distance apart; measuring an output signal derived from an electromotive force of said cell element and from a pump current flowing through said pump element, thereby measuring a deviation from a stoichiometric point of said mixture; and measuring a change in electrical properties of said metal oxide, thereby measuring the direction of said deviation from said stoichiometric point.
Claim 10
Independent Claim
141 words
A method for measuring air/fuel ratio, comprising the steps of: placing within a chamber containing an air/fuel mixture to be measured a solid electrolyte electrochemical cell element actuated by an oxygen concentration difference and a solid electrolyte pump element, each element being in the form of an oxygen ion conductive solid electrolyte having a porous electrode formed on each side; placing within said chamber a semiconducting metal oxide layer, said metal oxide, said cell element and said pump element being disposed a small distance apart; measuring an output signal derived from an electromotive force of said cell element and from a pump current flowing through said pump element, thereby measuring a deviation from a stoichiometric point of said mixture; and measuring a change in electrical properties of said metal oxide, thereby measuring the direction of said deviation from said stoichiometric point.
Claim 11
Dependent Claim
29 words
A method as recited in claim 6, further comprising holding said electromotive force substantially constant and wherein said step of measuring an output signal comprises measuring said pump current.
Claim 12
Dependent Claim
32 words
A method as recited in claim 6, further comprising the step of holding said pump current substantially constant and wherein said step of measuring an output signal comprises measuring said electromotive force.
Claim 13
Dependent Claim
21 words
A method as recited in claim 6, further comprising the step of resistively heating said cell element and said pump element.
Claim 14
Dependent Claim
19 words
A method as recited in claim 9, further comprising the step of resistively heating said semiconducting metal oxide layer.
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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) | 1991-02-01 | 1991-08-03 | 1992-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-01 | 1995-08-03 | 1996-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-01 | 1999-08-03 | 2000-02-02 | $7700.00 | Window Closed / Lapsed |