Denso Corporation

Nippon Soken, Inc.

Kiyomi Kobayashi

Namitsugu Fujii

Hiromi Sano

Yasumichi Hotta

Motoaki Satou

Naoto Miwa

Toshitaka Saito

Makoto Nakae

Masanobu Yamauchi

Toru Katafuchi

Zhenzhou Su

Gang E

Kazuhiko Koike

Takehito Kimata

Makoto Noguchi

Shoichiro Emmei

Tooru Katafuchi

Akira Saito

Kazuki Yagi

Toshikazu Hirose

Tomoaki c/o Daiken Chemical Co Ltd Tsujimoto

Akio c/o Daiken Chemical Co Ltd Harada

Tsuyoshi c/o Daiken Chemical Co Ltd Nishi

A sensor element of a gas sensor includes a solid electrolyte body which has oxygen-ion conductivity, a measuring electrode that is exposed to a measured gas, a reference gas electrode that is exposed to a reference gas, and a porous protection layer. The measuring electrode is mounted on an outer surface of the solid electrolyte body. The reference electrode is mounted on an inner surface of the solid electrolyte body. The protection layer covers a surface of the measuring electrode. A plurality of open portions are formed to penetrate through the measuring electrode. A part of the protection layer is joined to the solid electrolyte body, via the plurality of open portions.

Gas sensor

A gas sensor has a gas sensor element which has a solid electrolyte body, a reference electrode and a measuring electrode. The solid electrolyte body contains partially stabilized zirconia as a main component in which zirconia is stabilized by stabilizer agent. Particle boundary parts are formed between crystal particles made of the partially stabilized zirconia. The particle boundary parts are made of a metal element such as yttria derived from the stabilizer agent, an alumina component and a silica component. A total content of the alumina component and the silica component in the particle boundary parts in the solid electrolyte body is within a range of 0.01 mass % to 1 mass % in terms of oxide in the solid electrolyte body. A ratio of the alumina component to the silica component in the particle boundary partsis within a range of 0.2 to 2.0 in terms of oxide.

Solid electrolyte body and gas sensor

A solid electrolyte is made of zirconia grains containing yttria and alumina grains dispersed in the zirconia grains. In the solid electrolyte, the yttria content per zirconia content is within a range of 2 to 10 mol. %, the relative density is not less than 93%, and the average particle size Rz of the zirconia grains is not more than 2 &#x3bc;m, an average particle size Ra of the alumina grains is not more than 1 &#x3bc;m. The average particle size Ra of the alumina grains is smaller than the average particle size Rz of the zirconia grains. An average distance value Abetween the alumina grains is not more than 2 &#x3bc;m, and a standard deviation Sthereof is not more than 0.8. The solid electrolyte satisfies a relationship of (S/A)&#xd7;Rz&#x2266;0.9.

Solid electrolyte, method of producing the solid electrolyte, and gas sensor equipped with gas sensor element using the solid electrolyte

A gas sensor has a cylindrical housing case, a gas sensor element as a sensor component, and a filler portion. The filler portion is formed between the inner surface of the cylindrical housing case and the outer surface of the gas sensor element. The filler portion is filled with filler powder composed of talc as a layered compound. Talc is a principal ingredient of the filler powder. The space formed between the cylindrical housing case and the gas sensor element is sealed with the filler powder in the filler portion. The filler powder in the filler portion has a degree of c-axis orientation within a range of 60% to 85%, The filler powder in the filler portion has a porosity of not more than 10%.

The present invention provides, as one aspect, a gas sensor element including a solid electrolytic substance having a bottomed cylindrical shape and oxygen ion conductivity, a reference electrode arranged on an inner side surface of the solid electrolytic substance, a measuring electrode arranged on an outer side surface of the solid electrolytic substance, and a protective layer which covers the outer side surface of the solid electrolytic substance together with the measuring electrode and which allows gas to be measured to pass through the protective layer, wherein an end side of the gas sensor element is formed of a leg portion whose profile line is straight on an axial cross section and a bottom portion whose profile line is curved, and the film thickness of the protective layer of the bottom portion is larger than the film thickness of the protective layer of the leg portion.

Gas sensor element and gas sensor including the same

A gas sensor element with a bottom part is composed of at least a solid electrolyte body of oxygen ion conductivity, a reference electrode, a detection electrode, an electrode protection layer which supports noble metal catalyst, and a heater. The electrode protection layer is composed of a covering layer, a catalyst layer and a poisoning layer. A quantity of the noble metal catalyst supported in the electrode protection layer at the bottom part of the gas sensor element is larger than that in the electrode protection layer at a leg part of the gas sensor. The bottom part of the gas sensor element has a high temperature rising speed more than the leg part when the heater generates heat energy.

Gas sensor element and gas sensor equipped with the same

A gas sensing member has a unit structure and a porous protective layer disposed on the unit structure. The unit structure has a solid electrolyte body, a gas measurement electrode disposed on a surface of the body and exposed to a measured gas entering at a gas inlet, a reference gas electrode disposed on another surface of the body and exposed to a reference gas, and a heater disposed close to the body. The heater has a heater substrate and heating elements disposed in the heater substrate. The heating elements heat the body. The heater substrate has side corner areas placed on side corners of the unit structure and being adjacent to the heating elements. The protective layer is disposed on the gas inlet such that the side corner areas are not covered with the protective layer and are directly exposed to the measured gas.

Gas sensing member used for gas sensor and method of manufacturing the member

A gas sensor is equipped with a built-in ceramic heater. The gas sensor detects the concentration of a predetermined gas component contained in the exhaust gas. The ceramic heater has a heater base member made of ceramic, a heating element formed in the inside of the heater base material, and a pair of external electrode pads that is electrically connected to the output terminals for the outer leads. The external electrode pads, the heating element, and the heater leads are made of base metal. The outer surface of each external electrode pad is covered only with a dense protective film made of noble metal such as gold (Au), silver (Ag), platinum (Pt), rhodium (Rh), and palladium (Pd).

Ceramic heater, gas sensor, and method of producing ceramic heater

A ceramic laminate body, a gas sensor element employing such a ceramic laminate body and related manufacturing method are disclosed as including first and second ceramic sheets, made of material compositions different from each other, and an intermediate bonding layer, bonding the first and second ceramic sheets to each other so as to form a closed hollow space between the first and second ceramic sheets. The intermediate bonding layer has a multilayer structure including first and second unit intermediate layers laminated on each other such that innermost end portions of the first and second unit intermediate layers are displaced from each other to adapt a difference in degreasing contraction rates of associated component parts.

Ceramic laminate body, gas sensor element and related manufacturing method

A powder filler is stuffed in a filler space defined between a housing and a gas sensing element so as to airtightly seal a clearance between the housing and the gas sensing element. The powder filler contains grains whose diameter is in a range from 80 &#x3bc;m to 5,000 &#x3bc;m when measured before being stuffed into the filler space. A weight percentage of the grains having the diameter of 80 &#x3bc;m to 5,000 &#x3bc;m is equal to or larger than 80% with respect to an overall weight of the powder filler.

A gas sensor has a sensor element inserted in a cylindrical housing. A measured gas cover, provided at a distal end side of the housing, forms a measured gas environment at a distal end side of the sensor element. An atmospheric air cover, provided at a proximal end side of the housing, forms an atmospheric air environment at a proximal end side of the sensor element. A clearance between an inside surface of the housing and an outside surface of the sensor element is gastightly sealed with a sealing member including a plurality of powder filler layers to separate or isolate the measured gas environment from the atmospheric air environment.

A gas sensing element has a solid electrolytic body, a reference gas side electrode provided on a surface of the solid electrolytic body so as to be exposed to a reference gas, and a measured gas side electrode provided on another surface of the solid electrolytic body so as to be exposed to a measured gas. A crystal face strength ratio of the measured gas side electrode according to X-ray diffraction is 0.7&#x2266;{I(200)/I(111)} or 0.6&#x2266;{I(220)/I(111)}.

Gas sensing element and method for manufacturing the same

A second protective layer is a ceramic porous protective layer comprising coarse particles and fine particles structurally arranged in such a manner that interparticle cavities formed between the coarse particles are filled with the fine particles. At least either of the coarse particles and the fine particles contain at least one selected from the group consisting of &ggr;-Al2O3, &thgr;-Al2O3, &dgr;-Al2O3 and solid solution having the same crystal structure as those of &ggr;-Al2O3, &thgr;-Al2O3, &dgr;-Al2O3.

Gas sensing element incorporated in a gas sensor for an internal combustion engine

A gas sensing element has a solid electrolytic body, a reference gas side electrode provided on a surface of the solid electrolytic body so as to be exposed to a reference gas, and a measured gas side electrode provided on another surface of the solid electrolytic body so as to be exposed to a measured gas. A crystal face strength ratio of the measured gas side electrode according to X-ray diffraction is 0.7&lE;&lcub;I( )/I( )&rcub; or 0.6&lE;&lcub;I( )/I( )&rcub;.

A solid electrolytic body has an inside space serving as a reference gas chamber. A sensing electrode and a reference electrode are formed on the surface of the solid electrolytic body. A heater is disposed in the reference gas chamber. A contact portion comprises a region where the heater is brought into contact with the inner surface of the solid electrolytic body and an opposing region on the outer surface of the solid electrolytic body. The sensing electrode includes at least part of the contact portion. A gas receiving surface region, exposed to the measuring gas, extends from an element tip to a position spaced by a distance L away from the element tip. At least part of the contact portion is located in a region extending from the element tip to a position spaced by a distance 0.4L away from the element tip. The sensing electrode is entirely located in a region extending from the element tip to a position spaced by a distance 0.8L away from the element tip.

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Kuwana, Japan

Kiyomi Kobayashi