Ngk Spark Plug Company, Limited

Ngk Spark Plug So., Ltd.

Takao Kojima

Hiroyuki Ishiguro

Masaru Yamano

Tetsusyo Yamada

Masahiko Yamada

Yoshiaki Kuroki

Toshiki Sawada

Masashi Ando

Noriaki Kondo

Yoshiaki Matsubara

Kazuo Taguchi

Ken Minoha

Yutaka Nakayama

Yoshihide Kami

Toshikatsu Yasuda

Kanehisa Kitsukawa

Katsuyoshi Mizumoto

Akio Takami

Shigeki Mori

Toshitaka Matsuura

Yutaka Adachi

Yoshiro Noda

Shinya Awano

Ryohei Aoki

Keisuke Makino

Akira Nakano

Koichi Imaeda

Yoshiki Kawachi

Sinya Awano

Shigeru Miyata

Nobuhiro Hayakawa

Satoshi Sugaya

Takayoshi Atsumi

Hiroshi Isomura

Keita Nakagawa

Hiroshi Matsuzaki

Tetsuma Shimozato

Kunio Yanagi

Takuya Saito

Hideki Toyoda

Mitsuru Kondo

Toru Furuichi

Yasuhiro Ujita

Kouzou Amano

Yoshiyuki Ohtake

Mitsunori Ooi

Koichi Takahashi

Naoto Naganuma

A gas sensor () having a laminate including an alumina substrate () having a heating resister () embedded in the alumina substrate (); a first oxygen-ion conductive solid electrolyte layer () containing zirconia and alumina and partly constituting an oxygen-detecting cell () and the first solid electrolyte layer () being laminated with said alumina substrate (); a second oxygen-ion conductive solid electrolyte layer () containing zirconia and alumina and partly constituting an oxygen-pumping cell (); an ion-leakage preventing ceramic spacer () for preventing oxygen-ions from leaking from the second oxygen-ion conductive solid electrolyte layer () to the first oxygen-ion conductive solid electrolyte layer (), the spacer () being laminated between the first and second oxygen-ion conductive solid electrolyte layers (); and a gas-diffusion space () formed between an electrode () of the oxygen-detecting cell () and an electrodes () of the oxygen-pumping cell (). Furthermore, the laminate () is co-fired. Preferably, the zirconia contained at least in the second solid electrolyte layer is made of partially stabilized zirconia, the phase formed in the zirconia consisting essentially of tetragonal and cubic phases. Additionally, an ionic migration-preventing electrode () is optionally embedded in the alumina substrate () for preventing metal ion migration.

Gas sensor having a laminate comprising solid electrolyte layers and alumina substrate

A gas sensor element having an element body, the element body including: a ceramic heater having ceramic layers and a heater element embedded in the ceramic layers; and a solid electrolyte layer including a detection section covered by a pair of electrodes, the solid electrolyte layer being laminated together with the ceramic heater. Furthermore, the element body has a width at a front portion including the detection section smaller than at a rear portion, and at least both side edge faces of the front portion of the element body are covered with a porous layer.

Lamination-type gas sensor element and gas sensor

A gas sensor having a gas sensor element which includes: a reference electrode; a solid electrolyte layer having oxygen ion conductivity; a detection electrode; and an electrode-protecting layer covering the detection electrode. The electrode-protecting layer is a porous body carrying catalytic metal, and includes: a detection electrode side portion having a catalytic metal loading ratio of more than 0% by weight and not more than 0.005% by weight; and a surface side portion provided closer to the outer surface of the electrode-protecting layer than the detection electrode side portion, the surface side portion having a catalytic metal loading ratio of 0.01% by weight or more.

Gas sensor and method for manufacturing the same

A prismatic ceramic heater for heating a gas sensor element includes a heating resistor embedded in ceramic, and has a substantially rectangular cross section. At least part of a longitudinally extending edge portion of the prismatic ceramic heater is located in the vicinity of the heating resistor. This part of the longitudinally extending edge portion is coated with a porous protective layer. The protective layer has a thickness not less than 20 &#x3bc;m and a curved surface of a curvature radius not less than 10 &#x3bc;m. The protective layer prevents cracking induced by contact with water.

Prismatic ceramic heater for heating gas sensor element, prismatic gas sensor element in multilayered structure including the prismatic ceramic heater, and method for manufacturing the prismatic ceramic heater and prismatic gas sensor element

A solid electrolyte layer or body capable of being co-fired with an insulating ceramic substrate or body to be used as a gas sensor laminate. The gas sensor laminate is preferably composed of an alumina substrate () and an oxygen-ion conductive solid electrolyte layer () bonded to the alumina substrate () by firing. The oxygen-ion conductive solid electrolyte layer or body is formed from partially or wholly stabilized zirconia, which layer contains alumina in an amount of 10% to 80% by weight, particularly 30% to 75% by weight. In this manner, another ceramic layer; particularly, a ceramic layer () of alumina can further be bonded to the oxygen-ion conductive solid electrolyte layer. The relative density of the ceramic layer can be 60% to 99.5%, preferably 80% to 99.5%.

Solid electrolyte containing insulating grains for gas sensor

A solid electrolyte layer or body capable of being co-fired with an insulating ceramic substrate or body to be used as a gas sensor laminate. The gas sensor laminate is preferably composed of an alumina substrate ( ) and an oxygen-ion conductive solid electrolyte layer ( ) bonded to the alumina substrate ( ) by firing. The oxygen-ion conductive solid electrolyte layer or body is formed from partially or wholly stabilized zirconia, which layer contains alumina in an amount of 10% to 80% by weight, particularly 30% to 75% by weight. In this manner, another ceramic layer; particularly, a ceramic layer ( ) of alumina can further be bonded to the oxygen-ion conductive solid electrolyte layer. The relative density of the ceramic layer can be 60% to 99.5%, preferably 80% to 99.5%.

Solid electrolyte containing insulating ceramic grains for gas sensor

There are proposed an air/fuel ratio sensor which can detect a wide range of an air/fuel ratio and provides a simple structure, a superior mechanical strength or durability and a reduced manufacture cost, and a method of detecting the air/fuel ratio using the air/fuel ratio sensor. An air/fuel ratio sensor 1 is formed of a detecting portion 2 and a heater portion 3 laminated via a porous body 16. In the detecting portion 2, on an inner face of a plate-like solid electrolytic body 5, a reference electrode 7 is provided for controlling an oxygen gas diffusion rate, and on an outer face of the solid electrolytic body 5, a measurement electrode 6 is provided. A surface of the measurement electrode 6, on which the diffusion rate is not controlled, is covered with a protective layer 14 having an ventilation property to a degree to which the diffusion rate is not substantially controlled. A lead portion 7b of the reference electrode 7 is a porous layer which substantially controls the diffusion rate. The lead portion 7b is exposed to an exhaust gas via a connecting hole 13 which connects the lead potion 7b and the protective layer 14.

Wide range air/fuel ratio sensor having one electrochemical cell

A ceramic heater for heating a sensor such as an oxygen sensor has a ceramic substrate and a heater pattern formed on the substrate. A heater pattern 22 is tightly interposed between first and second alumina substrates 15 and 21. This heater pattern 22 has a meandering heating section 25 and a pair of leads 26 for connecting both ends of the heating section 25 to two terminals at the base side end. The heating section 25 is divided into a tip side subsection 25a located near the tip side end of the device, and a base side subsection 25b. Specifically, the wire width is made greater in the tip side subsection 25a than in the base side subsection 25b so that the resistance per unit length is lower in the tip side subsection 25a. The thus-designed heater section 25 produces a less amount of heat in the tip side subsection than in the base side subsection, and this distribution of heat generation can reduce the possibility of cracks and breakage of a wire.

Ceramic heater and oxygen sensor

Oxygen sensor element (ZrO.sub.2 solid electrolyte etc) for detecting oxygen concentration in an exhaust gas has a protective layer which is made of a heat-resistant metal oxide and which carries a component of a IIa subgroup element (Ca, Mg etc) on the side exposed to the exhaust gas of the sensor element, at least a part of the protective layer being present as a nonstoichiometric compound (Ti oxide etc) with respect to the heat-resistant metal oxide. Si-poisoning is prevented. Heater for heating the sensor element is provided for preventing Si-poisoning at low temperatures.

Oxygen sensor for preventing silicon poisoning

Poisoning-preventive and poisoning-resistant materials are described, including: a poisoning-preventive layer-possessing support including a support and, formed thereon, a poisoning-preventive layer having a compound containing at least one element selected from the Group IIa element of the periodic table.

Poisoning-preventive layer-possessing support, poisoning-resistant

A poisoning-resistant catalyst for a catalytic converter, includes a support, a noble metal catalytic component deposited on the support, and a poisoning-preventive layer formed on the side of the catalytic component exposed to an exhaust gas, said poisoning-preventive layer having a compound containing at least one element selected from the Group IIa elements of the periodic table.

Poisoning resistant catalyst for exhaust gas converters

An improved piezoelectric sensor for detecting pressure, vibration, acceleration or the like physical quantity is disclosed. The pressure sensor to be attached to a cylinder block of an internal combustion engine includes a main body adapted to be attached to the cylinder and defining an axially extending hole therewithin, a diaphragm attached to one end of the main body for closing the hole; and a piezoelectric element disposed within the hole so that the pressure within the cylinder is transmitted to the piezoelectric element through the diaphragm. The piezoelectric element is a circular or polygonal disc with a thickness of 0.3-1.5 mm and is formed of a single crystal piezoelectric ceramic having a Curie temperature greater than 500.degree. C., such as LiNbO.sub.3.

Piezoelectric sensor

An oxygen sensor element comprises a reference-gas-side electrode on one surface of a solid electrolyte having oxygen-ion conductivity, a detection-gas-side electrode on another surface, and a porous coated layer formed of a heat-resistant metal oxide formed on the surface of the detection-gas-side electrode, wherein at least a part of said coated layer is formed of a nonstoichiometric compound of transition metal (Ti, Co, Ni) oxide, and a portion formed of said nonstoichiometric compound carries a catalyst for equilibrating gas components of a detection gas. The catalyst (Pt, Rh) is 0.2-5 mole % relative to the portion formed of said nonstoichiometric compound. The coated layer may be thickened at the distal end portion.

Oxygen sensor element

In an oxygen sensor of the type having an oxygen ion conductive tube of solid electrolyte, a ceramic heater disposed within the oxygen ion conductive tube for heating the same is in the form of a quadrangular prism or a bar of a rectangular cross section. The ceramic heater is formed by piling up ceramic green sheets with metallic thick-film patterns for heat generating resistors interposed between adjacent two of the ceramic green sheets. The ceramic heater is so shaped as to satisfy the relation of b/a=0.75.about.1 where 'a' is the width and 'b' is the thickness of the ceramic heater. The metallic thick films, which the metallic thick-film patterns are turned to by firing, are arranged so as to be parallel to the side surfaces opposed in the thickness direction of the ceramic heater.

Ceramic heater for oxygen sensor of the type having oxygen ion

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Aichi, Japan

Takao Kojima