Ngk Spark Plug Company, Limited

Kazuo Taguchi

Hisaharu Nishio

Takao Kojima

Masahiko Yamada

Hiroyuki Ishiguro

Katsuhisa Yabuta

Masaru Yamano

Keiichi Noda

Toshiki Sawada

Toshio Okumura

Akio Ebizawa

Koichi Shimamura

Noriaki Kondo

Koji Kano

Mitsuo Kusa

A gas sensor includes an outer cylinder a metallic shell and a sensor element The metallic shell is disposed inside the outer cylinder The sensor element is disposed in a through-hole formed in the metallic shell and is adapted to detect a component of a gas to be measured. A sealing material layer is mainly made of glass and is disposed between the inner surface of the metallic shell and the outer surface of the sensor element A cushion layer formed of a porous inorganic substance is disposed in contact with the end of the sealing material layer on the front-end side with respect to the axial direction of the sensor element A cushion layer formed of talc glass is disposed in contact with the end of the sealing material layer on the rear-end side with respect to the axial direction of the sensor element A gas sensor according to the present invention is especially adapted for use in a motorcycle and includes a sensor element having lower susceptibility to mechanical shock or thermal stress induced by different rates of contraction between a sealing material layer and an adjacent component element as well as excellent durability.

Gas sensor with multiple mechanical and thermal shock cushion layers

A gas sensor includes an outer cylinder a metallic shell and a sensor element The metallic shell is disposed inside the outer cylinder The sensor element is disposed in a through-hole formed in the metallic shell and is adapted to detect a component of a gas to be measured. A sealing material layer is mainly made of glass and is disposed between the outer surface of the sensor element and the inner surface of the metallic shell or between the outer surface of the sensor element and the inner surface of an insulator disposed between the metallic shell and the sensor element Cushion layer and are each made of a porous inorganic substance. At least either the cushion layer or is disposed so as to abut one end of the sealing material layer A gas sensor according to the present invention includes a sensor element featuring lower susceptibility to mechanical shock or thermal stress induced by different rates of contraction between a sealing material layer and an adjacent component element, as well as excellent durability.

Gas sensor

A gas sensor has a structure in which an insulator is disposed inside a metallic shell, and a sensor element is disposed inside the insulator. A cavity is formed in the insulator to surround the sensor element. A sealing material mainly formed of glass is charged into the cavity in order to establish sealing between the inner surface of the insulator and the outer surface of the sensor element. The sensor element has a rectangular cross section, and the inner surface of the insulator defining the cavity has a sectional profile corresponding to the sectional profile of the sensor element.

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

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.

Method of producing oxygen sensor for air-fuel ratio control having a

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.

Oxygen sensor for air-fuel ratio control having a protective layer

A gas sensor including a gas sensor body in which is centrally inserted a gas detecting element and which permits the gas sensor itself to be attached to other members; a protective sleeve attached to an end portion of the gas sensor body; a seal member formed of a heat-resistant synthetic resin, the seal member being disposed inside an end portion on a lead wire draw-out side of the protective sleeve, with a lead wire extending through the seal member; and a spring member mounted within the protective sleeve for urging the seal member liquid-tightly against the lead wire draw-out side end portion of the protective sleeve. Since the seal member disposed in an end portion of the protective sleeve is formed of a heat-resistant synthetic resin, the durability thereof is improved even where high temperature gases such as the exhaust gases of internal combustion engines or the like are to be detected. Moreover, since the seal member is pushed against the end portion of the protective sleeve, no gas is formed between the protective sleeve and the seal member, whereby the ingress of liquid can be prevented.

A heater-incorporating oxygen sensor includes a solid electrolyte oxygen sensor element comprising a solid electrolyte provided with electrodes on both its sides and a heater, said heater being a ceramic heater formed by sintering and embedding a metallized pattern in a ceramic insulator as one solid body, said ceramic heater being disposed within a space surrounded with said oxygen sensor element.

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Nagoya, Japan

Kazuo Taguchi