Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
172 words
An oxygen concentration-detecting apparatus comprising a ceramic substrate for generating an electromotive force between a first surface contacted with a reference gas and a second surface contacted with a gas to be detected according to the ratio of the concentration of oxygen gas O₂ between said two gases, a pair of electrode members formed at parts of said first and second surfaces, respectively, of said ceramic substrate, to take out said electromotive force as a detection signal, a first oxidation catalyst layer for promoting mainly oxidation reaction of unburnt components, which is arranged to cover said second surface of said ceramic substrate and an outer surface of the electrode member on the second surface, a laminate of a protecting layer of a metal oxide covering the outer surface of said ceramic substrate and a reduction catalyst layer for promoting mainly reduction reaction of nitrogen oxides NOx, and a second oxidation catalyst layer for promoting mainly oxidation reaction of hydrogen gas H₂, which is arranged to cover an outer surface of said laminate.
Claim 2
Dependent Claim
172 words
An oxygen concentration-detecting apparatus comprising a ceramic substrate for generating an electromotive force between a first surface contacted with a reference gas and a second surface contacted with a gas to be detected according to the ratio of the concentration of oxygen gas O₂ between said two gases, a pair of electrode members formed at parts of said first and second surfaces, respectively, of said ceramic substrate, to take out said electromotive force as a detection signal, a first oxidation catalyst layer for promoting mainly oxidation reaction of unburnt components, which is arranged to cover said second surface of said ceramic substrate and an outer surface of the electrode member on the second surface, a laminate of a protecting layer of a metal oxide covering the outer surface of said ceramic substrate and a reduction catalyst layer for promoting mainly reduction reaction of nitrogen oxides NOx, and a second oxidation catalyst layer for promoting mainly oxidation reaction of hydrogen gas H₂, which is arranged to cover an outer surface of said laminate.
Claim 3
Dependent Claim
35 words
An oxygen gas concentration-detecting apparatus as set forth in claim 1, wherein said ceramic substrate is constructed by incorporating a small amount of yttria Y₂O₃ or calcia CaO into zirconia ZrO₂ and calcining the mixture.
Claim 4
Dependent Claim
25 words
An oxygen gas concentration-detecting apparatus as set forth in claim 1, wherein said ceramic substrate has a shape resembling the shape of a test tube.
Claim 5
Dependent Claim
34 words
An oxygen gas concentration-detecting apparatus as set forth in claim 1, wherein a reference stable gas is the air and the gas to be detected is an exhaust gas of an internal combustion engine.
Claim 6
Dependent Claim
48 words
An oxygen gas concentration-detecting apparatus as set forth in claim 1, wherein said ceramic substrate has a shape resembling the shape of a test tube, said first surface is an inner surface of the ceramic substrate, and said second surface is an outer surface of said ceramic substrate.
Claim 7
Dependent Claim
39 words
An oxygen gas concentration-detecting apparatus as set forth in claim 1, wherein said first oxidation catalyst layer is formed by vacuum-depositing platinum Pt on said ceramic substrate, the electrode member on the surface thereof and the outer surface threrof.
Claim 8
Dependent Claim
21 words
An oxygen gas concentration-detecting apparatus as set forth in claim 1, wherein said protecting layer is formed by flame-spraying magnesium spinel.
Claim 9
Dependent Claim
35 words
An oxygen gas concentration-detecting apparatus as set forth in claim 1, wherein said the second oxidation catalyst layer is an oxidation catalyst comprising Al₂O₃ as a carrier and platinum Pt or palladium Pd supported thereon.
Claim 10
Dependent Claim
29 words
An oxygen gas concentration-detecting apparatus as set forth in claim 1, wherein said reduction catalyst layer is a reduction catalyst layer having rhodium Rh or ruthenium Ru incorporated therein.
Claim 11
Dependent Claim
31 words
An oxygen gas concentration-detecting appratus as set forth in claim 1, wherein said reduction catalyst layer comprises a carrier of TiO₂ and rhodium Rh or ruthenium Ru incorporated in the carrier.
Claim 12
Dependent Claim
33 words
An oxygen gas concentration-detecting apparatus as set forth in claim 1, wherein said reduction catalyst layer comprises a carrier of lanthanum oxide La₂O₃ and rhodium Rh or ruthenium Ru incorporated in the carrier.
Claim 13
Dependent Claim
45 words
An oxygen gas concentration-detecting apparatus as set forth in claim 1, wherein said reduction catalyst layer is constructed by supporting particles of a reduction catalyst for promoting reduction reaction of nitrogen oxides NOx on cerium oxide and incorporating the supported particles in a porous layer.
Claim 14
Dependent Claim
26 words
An oxygen gas concentration-detecting apparatus as set forth in claim 1, wherein said reduction catalyst layer is laminated on the outer side of the protecting layer.
Claim 15
Dependent Claim
26 words
An oxygen gas concentration-detecting apparatus as set forth in claim 1, wherein said protecting layer is laminated on the outer side of the reduction catalyst layer.