Ngk Spark Plug Company, Limited

Shigehiro Ohtsuka

Masaki Mizutani

Masaki Onkawa

Shun Sakuma

Toru Iwano

Tatsuhiko Muraoka

Keisuke Nakagawa

Kazuma Ito

Ippei Kato

Hisashi Kozuka

Tomohiro Nishi

A gas sensor control apparatus including a gas sensor element, a heater for heating the gas sensor element, and heater energization control means for feedback controlling the supply of electric current to the heater such that the internal resistance of the gas sensor element coincides with a target resistance. The gas sensor element has a solid electrolyte member and an electrode portion including an outside electrode and an inside electrode. At least a portion of the electrode portion is formed of an electrically conductive oxide whose main component is (i) a first perovskite phase which is represented by a composition formula of LaCoNiO(0.300&#x2264;x&#x2264;0.600, 0&#x2264;d&#x2264;0.4) and has a perovskite-type crystal structure, or (ii) a second perovskite phase which is represented by a composition formula of LaFeNiO(0.450&#x2264;y&#x2264;0.700, 0&#x2264;d&#x2264;0.4) and has a perovskite-type crystal structure.

Gas sensor control apparatus

An inside lead portion of a gas sensor element has a lanthanum zirconate layer arranged between an electrically conductive oxide layer and a solid electrolyte member. Meanwhile, an inside detection electrode portion of the gas sensor element is formed such that (i) no lanthanum zirconate layer is formed between an electrically conductive oxide layer and the solid electrolyte member, or (ii) a lanthanum zirconate layer thinner than the lanthanum zirconate layer of the inside lead portion is formed between the electrically conductive oxide layer and the solid electrolyte member.

Gas sensor element and gas sensor

A gas sensor element has a protection layer smaller in heat capacity than a conventional protection layer formed by a dipping process. A gas sensor includes the gas sensor element. The gas sensor element is manufactured by a method of manufacturing. The gas sensor element includes at least one space formed between a protection layer and an element body. The space is positioned over at least one of four vertexes of a forward end of the element body at a location at which the thickness of the protection layer is likely to become small. Therefore, it is possible to restrain breakage of the vertexes of the forward end of the element body which could otherwise result from thermal shock stemming from adhesion of water. The protection layer of the gas sensor element can be reduced in thickness and thus in heat capacity as compared with a conventional protection layer.

Gas sensor element, gas sensor, and method of manufacturing gas sensor element

A gas sensor element in an air/fuel ratio sensor includes an element body and a protection layer having two layers (a first layer and a second layer). The gas sensor element has at least one separation portion in the form of a space between the first layer and the second layer. The gas sensor element can temporarily accumulate, in the at least one separation portion, water which adheres to the surface of the protection layer and penetrates into the protection layer. Thus, as compared with a protection layer which is identical in thickness to the protection layer, but does not have separation portions, water adhering to the protection layer is less likely to reach the element body. Therefore, there can be restrained breakage of an end of the element body which could otherwise result from thermal shock stemming from adhesion of water.

A gas sensor element comprises an elongated plate-like element including, at a forward end portion, a detecting section comprising a solid electrolyte body having an outer surface and a back surface, a detection electrode on the outer surface and a reference electrode on the back surface, and a porous layer covering the detection electrode. The coating layer includes a first protection layer entirely covering the detecting section, and a second protection layer circumferentially covering the first protection layer and extending at least from a forward end of the first protection layer to a position located rearward of the porous layer. The thickness of the first protection layer on the porous layer is larger than that of the first protection layer rearward of the porous layer. The thickness of the second protection layer rearward of the porous layer is larger than that of the second protection layer above the porous layer.

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Gifu, Japan

Shigehiro Ohtsuka