Ngk Spark Plug Company, Limited

Masaru Yamano

Takao Kojima

Toshiki Sawada

Masahiko Yamada

Hiroyuki Ishiguro

Ken Minoha

Kazuo Taguchi

Noriaki Kondo

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

Oxygen-sensor element comprises reference-gas-side and detection-gas-side electrodes on both surfaces of a solid-electrolyte body, and a porous protective layer on the surface of the detection-gas-side electrode, wherein at least a part (including at least a surface layer) of said porous protective layer is formed by a granular texture of a grain size of 0.1 to 0.5 .mu.m formed mainly of a nonstoichiometric compound of a transition metal oxide (TiO.sub.x), and a catalyst for having gas components of the gas to be measured react is carried in at least a part (including at least a surface layer) of the porous protective layer. Oxidation reaction of gas components is improved to prevent deterioration of the responsive property.

Oxygen-sensor element

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

Poisoning-preventive and poisoning-resistant materials including: a poisoning-preventive layer-possessing support comprising 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; a poisoning-resistant catalyst for catalytic converter, which comprises 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, the poisoning-preventive layer having a compound containing at least one element selected from the Group IIa elements of the periodic table; an exhaust gas converter device comprising a poisoning-preventive material provided on the exhaust gas inlet side, the poisoning-preventive material being either a ceramic material or the poisoning-preventive layer-possessing support as described above, the ceramic material comprising a compound containing at least one element selected from the Group IIa elements of the periodic table or comprising the compound and other ceramic compound, and a catalyst provided on the exhaust gas outlet side, the catalyst comprising a support and a noble metal catalytic component deposited on the support; and a poisoning-preventive gasoline composition comprising a gasoline and a compound containing at least one element selected from the Group IIa elements of the periodic table.

Exhaust gas converter device

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

This invention provides apparatus for detecting abnormality of an oxygen sensor accurately and also apparatus for appropriately controlling the air/fuel ratio of air and fuel mixture when an oxygen sensor is abnormal. The apparatus easily and properly detects a deteriorating oxygen sensor, with the use of which exhaust of nitrogen oxides or carbon monoxide increases, and when the oxygen sensor is determined to deteriorate, the feed back control of the air/fuel ratio of air and fuel mixture supplied to an internal combustion engine is preferably performed.

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Aichi, Japan

Masaru Yamano