Denso Corporation

Toyota Jidosha Kabushiki Kaisha

Keisuke Mizutani

Keigo Mizutani

Takashi Araki

Mitsunobu Nakato

Kazuhiko Koike

Keiichiro Aoki

Kazuhiro Wakao

Mikio Ishihara

Nobuyuki Tsuji

Shota Hagino

Hiroaki Kayama

Kana Asaoku

An exhaust gas purification filter is configured to he disposed in an exhaust passage in a gasoline engine. The exhaust gas purification filter includes partition walls including a plurality of pores, a plurality of cells partitioned by the partition walls, and sealing portions alternately sealing ends of a plurality of the cells in the exhaust gas purification filter. The partition walls each have an average pore diameter of more than 16 μm and less than 21 μm, and have a ratio of an average surface opening diameter of the pores in a partition wall surface to the average pore diameter of the partition wall of 0.66 or more and 0.94 or less.

Exhaust gas purification filter

An exhaust gas purification filter includes a honeycomb structure part and sealing parts. The honeycomb structure part has a porous partition wall and a plurality of cells defined by the partition wall to form exhaust gas flow paths. The sealing parts seal alternately a gas inflow-side end face or a gas outflow-side end face of the cells. The exhaust gas purification filter includes fine pores with diameters of 10 &#x3bc;m or less measured by the mercury intrusion method that account for 5% or more of all pores by volume in the honeycomb structure part. The partition wall has a plurality of communication pores communicating between the cells adjacent to the partition wall and has constricted communication pore of which a largest diameter &#x3a6;and a smallest diameter &#x3a6;satisfy relationships &#x3a6;&#x2265;50, 100&#xd7;&#x3a6;/&#x3a6;&#x2264;20.

The present invention provides a gas sensor capable of suppressing a variation of a sensor output by a sensor cell to be small. A sensor element of a gas sensor comprises a first solid electrolyte body and a second solid electrolyte body having oxygen ion conductivity, a measured gas chamber into which the measured gas is introduced, a first reference gas chamber and a second reference gas chamber into which reference gas is introduced, a first pump cell, a second pump cell, a sensor cell, and a heater. A value obtained by dividing a first average cross-sectional area of the first reference gas chamber by the first length is larger than the value obtained by dividing the second average cross-sectional area of the second reference gas chamber by the second length.

Gas sensor

A honeycomb structure body has a skin part of a cylindrical shape and a honeycomb structural part formed with the skin part together in a monolithic body. The skin part and the honeycomb structural part have partition walls of a porous structure. The cells have first cells arranged adjacent to the skin part and second cells arranged adjacent to the first cells. The skin part, the first cells and the second cells form an outer peripheral section. A central section is arranged inside the outer peripheral section. The honeycomb structure body satisfies a relationship in which a thermal expansion coefficient of the outer peripheral section is greater than a thermal expansion coefficient of the central section.

Honeycomb structure body

An air-fuel ratio detection device' comprises: a sensor element&#x2032; including a sensor cell; a voltage application circuit&#x2032; applying voltage to the sensor cell; a current detector&#x2032; detecting an output current of the sensor cell; an air-fuel ratio calculating partconfigured to calculate an air-fuel ratio of an exhaust gas; and a parameter detecting partconfigured to detect or calculate a temperature correlation parameter correlated with a temperature of the sensor element. The air-fuel ratio calculating part is configured to calculate the air-fuel ratio of the exhaust gas based on the temperature correlation parameter and the output current detected when a predetermined voltage is applied to the sensor cell.

Air-fuel ratio detection device and air-fuel ratio detection method

Provided is a gas sensor improving accuracy of detection of specific gas in measurement gas, while maintaining high responsiveness in detection of the specific gas. A sensor element of a gas sensor includes a first solid electrolyte and second solid electrolyte having oxygen ionic conductivity, a measurement gas chamber into which measurement gas is introduced, a first reference gas chamber and second reference gas chamber into which reference gas is introduced, a first pump cell, a second pump cell, a sensor cell, and a heater. The sensor cell detects a specific gas component in the measurement gas having an oxygen concentration adjusted by the pump cells. The heater is located opposite to a second principal surface of the second solid electrolyte on which the sensor cell is formed.

A gas sensor includes a pump cell unit that regulates the oxygen concentration of a measured gas using a pump electrode, a monitor cell unit that detects the residual oxygen concentration of the measured gas using a monitor electrode, and a sensor cell unit that detects the concentration of a specific gas component in the measured gas using a sensor electrode. Between a pump electrode lead part and the sensor electrode, there is arranged the monitor electrode. Between an upstream portion of the pump electrode lead part and a monitor electrode lead part, there is provided an interval wof 0.5 mm or more.

A gas sensor which can improve an accuracy in detecting a specific gas component by properly correcting for the influence of residual oxygen is provided. The gas sensor includes a solid electrolyte plate, a measured gas chamber into which a measured gas flows, a pump cell which adjusts an oxygen concentration of the measured gas using a pump electrode, a monitor cell which detects a residual oxygen concentration of the measured gas using a monitor electrode, and a sensor cell which detects a specific gas component concentration of the measured gas using a sensor electrode. The maximum thickness of the sensor electrode is greater than the maximum thickness of the monitor electrode, and the difference between the maximum thickness of the sensor electrode and the maximum thickness of the monitor electrode is between 4 &#x3bc;m and 30 &#x3bc;m, inclusive.

A gas sensor includes a sensor element having a measuring electrode and a reference electrode, a housing accommodating the sensor element, and an element cover including an inner cover having an inner side wall section and an inner bottom wall section, and an outer cover having an outer side wall section and an outer bottom wall section. Inner side surface holes and outer side surface holes are formed in the inner side wall section and the outer side wall section. Inner bottom surface holes and outer bottom surface holes are formed in the inner bottom wall section and the outer bottom wall section. The ratio of the total surface area of the outer side surface holes with respect to the total surface area of the inner bottom surface holes is 8 to 47. The total surface area of the inner side surface holes is 2 to 8 mm.

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Nisshin, Japan

Keisuke Mizutani