Abstract: A gas sensor includes a pump electrode disposed in a measured gas flow path, an oxygen detection electrode disposed in the measured gas flow path and containing platinum and zirconia, and a reference electrode disposed in a reference gas chamber where a reference gas exists, and containing platinum and zirconia. A first position of a front end of the pump electrode is located closer to a rear end side than a second position of a front end of the oxygen detection electrode is. When the content of zirconia in the oxygen detection electrode is X [%], and a ratio of a distance between the first and second positions to a longitudinal dimension of the pump electrode is Y [%], Y?141.96e?0.031X is satisfied. The content of zirconia is not lower than that of platinum in the reference electrode.

Abstract: A gas sensor includes: a laminate formed of a plurality of layers including at least one layer of a solid electrolyte; a reference gas chamber formed in the laminate and containing a reference gas; and a reference electrode partially exposed in the reference gas chamber. A portion which is not exposed in the reference gas chamber, of the reference electrode is sandwiched between, among the layers, a first layer and a second layer adjacent to the first layer. When an area of the portion sandwiched between the first layer and the second layer, of the reference electrode is defined as a first area, and an area of a portion exposed in the reference gas chamber, of the reference electrode is defined as a second area, a ratio of the first area to the second area is 0.3 or more.

Abstract: A gas sensor includes: a laminate including at least one layer made of a solid electrolyte; a measured gas flow path formed in the laminate; and a pump electrode exposed in the measured gas flow path. In a part of a rear end side region, the pump electrode is sandwiched between a first layer and a second layer or is covered with a covering layer formed on the inner surface of the measured gas flow path. The area of a portion exposed in the measured gas flow path, of the pump electrode is 4 mm2 or more. The area of a portion exposed in the measured gas flow path, of the front end side region is larger than the area of a portion exposed in the measured gas flow path, of the rear end side region.

Abstract: A sensor element includes a first pump cell including a first pump electrode and a first reference electrode, a first pump circuit including the first pump cell and a first reference electrode lead, a second pump cell including a second pump electrode and a second reference electrode and a second pump circuit including the second pump cell and a second pump electrode. A resistance value R2 of the second pump circuit is higher than a resistance value R1 of the first pump circuit, and a porosity P2 of the second reference electrode lead is higher than a porosity P1 of the first reference electrode lead.

Abstract: A gas sensor includes a sensor element, a tubular body made of metal, and a sealing material. The sensor element has a surface. The tubular body has a through hole which is formed along the axial direction and through which the sensor element is inserted. The sealing material is placed inside the through hole and between the inner peripheral surface of the through hole and the sensor element. The sealing material covers a part of the surface of the sensor element. When the sensor element is viewed in cross section from a second direction perpendicular to a first direction corresponding to the longitudinal direction of the sensor element, the sealing material forms a first inclination angle of not less than 10° and not more than 80° with respect to the surface.

Abstract: A metal terminal includes an element contacting portion which is disposed at one end of the metal terminal and is placed in contact with a sensor element, a lead wire retaining member which is disposed at another end of the metal terminal, and crimps and retains lead wires, a positioning member disposed between the one end and the other end and extending in a direction intersecting one direction, the positioning member positioning the metal terminal on a ceramic housing, and a guide member provided integrally with the positioning member at a site between the positioning member and the lead wire retaining member.

Abstract: A gas sensor includes a sensor element, an elastic insulating member, a plurality of lead wires, a plurality of metal terminals, and a ceramic housing. The plurality of lead wires are inserted in the elastic insulating member. The plurality of metal terminals each have a first end electrically connected to the sensor element, and a second end electrically connected to a corresponding one of the plurality of lead wires. The ceramic housing includes a plurality of insertion portions each including a through hole in which a corresponding one of the plurality of metal terminals is inserted, and at least one of the plurality of insertion portions has a different height from other insertion portions.

Abstract: A gas sensor includes a sensor element; a plurality of contact members holding a rear end portion of the sensor element and being electrically connected to the sensor element; a plurality of lead wires that are fixed at a position rearward of the sensor element and to which the contact members are electrically connected; and metal elastic members fixing the contact members and the lead wires with the contact members and lead wires being spaced apart from each other, and electrically connecting the contact members and the lead wires.

Abstract: A gas sensor includes: a sensor element; a plurality of element pads formed on a rear end portion of the sensor element; and a plurality of contact members holding the rear end portion of the sensor element and electrically connected respectively to the plurality of element pads. The plurality of contact members include contact members that each have an outer end surface protruding out from a corresponding one of end surfaces of the sensor element.

Abstract: A gas sensor includes: a sensor element; a plurality of element pads formed on a rear end portion of the sensor element; and a plurality of contact members holding the rear end portion of the sensor element and electrically connected respectively to the plurality of element pads. At least one contact member of the plurality of contact members has an end portion having a smaller width Wt than the other contact members.

Abstract: A gas sensor includes: a sensor element; a ceramic housing holding a rear end portion of the sensor element and provided with metal terminals electrically connected to the sensor element; and an elastic insulating member that is fixed in the rear of the sensor element and into which a plurality of lead wires electrically connected to the metal terminals are inserted. The elastic insulating member has one or more common spaces formed in a surface of the elastic insulating member that faces the ceramic housing. Two or more of the lead wires are arranged in each common space.

Abstract: A sensor element includes: a sensor electrode disposed on one main surface of a solid electrolyte layer to face a measurement gas introduction space, and having an oxygen decomposition ability and a NOx decomposition ability; a monitor electrode disposed on the one main surface of the solid electrolyte layer to face the measurement gas introduction space, and having the oxygen decomposition ability; and a reference electrode disposed on the other main surface of the solid electrolyte layer to face a reference gas introduction space, wherein a heater element of a heater part overlaps 50% or more of an area of each of the sensor electrode and the monitor electrode in plan view.

Abstract: A sensing electrode for sensing a predetermined gas component of a measurement gas, which is provided in a mixed-potential gas sensor that measures the concentration of the predetermined gas component, is formed of a cermet containing a noble metal and an oxygen-ion conductive solid electrolyte. The noble metal comprises Pt and Au. An Au abundance ratio, which is an area ratio of a portion covered with Au to a portion at which Pt is exposed in a surface of noble metal particles forming the sensing electrode, is 0.3 or more.

Abstract: A sensing electrode for sensing a predetermined gas component of a measurement gas, which is provided in a mixed-potential gas sensor that measures the concentration of the predetermined gas, component, is formed of a cermet containing a noble metal and an oxygen-ion conductive solid electrolyte. The noble metal comprises Pt and Au. An Au abundance ratio, which is an area ratio of a portion covered with Au to a portion at which Pt is exposed in a surface of noble metal particles forming the sensing electrode, is 0.3 or more.