Ngk Insulators, Inc.

Tomoya Seimori

Mika Murakami

Yosuke Adachi

Takayuki Sekiya

Yusuke Watanabe

Takashi Hino

Mika Kai

Naoya Saito

Jumpei Tanaka

Kengo Takeuchi

A sensor element includes: an element base including: a ceramic body made of an oxygen-ion conductive solid electrolyte, and having a gas inlet at one end portion thereof; at least one internal chamber located inside the ceramic body, and communicating with the gas inlet under predetermined diffusion resistance; an electrochemical pump cell including an electrode located on an outer surface of the ceramic body, an electrode facing the chamber, and a solid electrolyte located therebetween; and a heater buried in the ceramic body, and an leading-end protective layer being porous, and covering a leading end surface and four side surfaces in a predetermined range of the element base on the one end portion. The leading-end protective layer has an extension extending into the gas inlet, and fixed to an inner wall surface of the ceramic body demarcating the gas inlet.

Sensor element

Gas concentration detection sensor

A wetting test apparatus for a gas sensor includes: a pipe having a flow path therein; a blower for allowing a gas to flow through the flow path; a water supplier for supplying moisture to the flow path; at least one gas sensor for detecting at least one component of the gas flowing through the flow path; and a pressure variation generator for generating variations in a pressure of the gas flowing through the flow path by changing an effective cross-sectional area of the flow path.

Wetting test apparatus and method for gas sensor

An apparatus for evaluating a response time of gas sensors includes: a pipe; a first gas supplier for supplying a first gas to the pipe; a second gas adding machine for adding a second gas to the first gas in the pipe; and gas sensors for detecting components in a mixed gas of the first gas and the second gas, each of the gas sensors being attached to the pipe on a downstream side of an addition position of the second gas in a flow direction of the first gas. The second gas adding machine includes: a supply source of the second gas; a connecting pipe for connecting the supply source to the pipe; and a connecting pipe on-off valve for opening and closing the connecting pipe.

Apparatus and method for evaluating response time of gas sensor

A gas sensor includes a sensor element that includes a gas inlet through which a measurement target gas is introduced into the sensor element and a protective cover that contains a substance having a capability of decomposing ammonia. The protective cover has a gas-contact surface area within a range of 450 mmto 1145 mm, the gas-contact surface area being a sum of a surface area of a portion facing the inlet-side gas flow path and a surface area of a portion facing an in-element-chamber flow path of the sensor element chamber that is a shortest flow path for the measurement target gas from the element-chamber inlet to the gas inlet.

Gas sensor

The gas sensorhas a gas flow channelformed therein by an inner protection cover. The gas flow channelis formed in the pathway of measured gas from a first outer gas holeformed in an outer protection coverthat covers the tip end of a sensor elementto a gas inlet portof the sensor element. The gas flow channelextends from the rear end side to the tip end side of the sensor elementand is open to the sensor element chamberhaving the gas inlet portdisposed therein.

Gas sensor with flow channel formed by inner protective cover

In a gas sensor, a ratio A/Adefined by a ratio of an opening area Aper first inner gas hole and an opening area Aper second inner gas hole is set to higher than or equal to 0.9 and lower than or equal to 3.8 and, more preferably, to higher than or equal to 1.5 and lower than or equal to 1.9. Accordingly, adhesion of water to a sensor element can be sufficiently prevented. In addition, a ratio B/Bdefined by a ratio of a total opening area Bof the first inner gas holes to a total opening area Bof the second inner gas holes is set to higher than or equal to 0.85 and, more preferably, higher than or equal to 1.5. Accordingly, adhesion of water to the sensor element can be more reliably, effectively prevented.

A gas sensor is provided with a multilayer body of solid electrolyte layers, a measurement electrode, a reference electrode, a reference gas introduction layer, a detection unit and a heater. The reference electrode and the measurement electrode are formed directly on the same first solid electrolyte layer. Thus, heat from the heater is transferred from a third substrate layer to the first solid electrolyte layer, and also to the reference electrode and the measurement electrode through the same first solid electrolyte layer. The reference electrode is covered with a reference gas introduction layer, formed of a porous body. The transference of heat from the heater to the reference electrode through the reference gas introduction layer is smaller than the transference of heat from the heater to the reference electrode through the first solid electrolyte layer on which the reference electrode is formed directly.

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Nagoya, Japan

Tomoya Seimori