Abstract: A gas sensor element, wherein an amount of flexure in a first section extending in a longitudinal direction of the sensor element from the position 8/27 of a size of the element apart from one end of the element to the other end, is set to be greater than or equal to 1/1360 and less than or equal to 1/670 with respect to the size in the longitudinal direction of the element. The amount of flexure is a sum of a distance from a regression line to an upper side maximum displacement point and a distance from the regression line to a lower side maximum displacement point when calculating the regression line representing the relation of the position X in the longitudinal direction of the element and the displacement Y in a thickness direction from a plurality of data sets showing the relation of position X and displacement Y.

Abstract: A solid electrolyte body is placed on and fixed to an upper plate of a press jig such that a major surface (an upper surface) of the solid electrolyte body faces one major surface of a guide plate having an open space. The upper plate is rotated by a transfer mechanism to incline the solid electrolyte body in one direction, and the inclined solid electrolyte body is moved toward the other major surface of the guide plate such that a first edge of the solid electrolyte body protrudes from the open space. Then, a cutter is slid along the other major surface, so that the first edge is chamfered to form a first chamfered portion.

Abstract: A gas sensor element including: a sensor layer in which at least one pair of electrodes are provided in a solid electrolyte for measuring an electromotive force based on a difference in an oxygen concentration between atmospheres; and a heater layer which includes a heater element with a heat generating portion and an electrically insulating layer disposed so as to enclose the heater element and which is configured to heat, by an electric current supplied to the heater element, at least a portion of the solid electrolyte at which the at least one pair of electrodes are provided, the sensor layer and the heater layer being laminated integrally on each other, wherein the electrically insulating layer contains at least one metal oxide selected from the group consisting of alkali metal oxide and alkaline earth metal oxide.

Abstract: A NOx-decomposing electrode is provided having a certain or a high NOx-decomposing/reducing ability, which is formed on a third solid electrolyte layer for decomposing a NOx to produce oxygen. The detecting electrode contains a noble metal Pt, a material ZrO2 of the third solid electrolyte layer, and a mixture containing silica (SiO2) and alumina (Al2O3). Specifically, the detecting electrode contains 80% to 90% by weight of the Pt, 9.5% to 19.8% by weight of the ZrO2, and 0.2% to 0.5% by weight of the mixture containing silica and alumina.

Abstract: A technology which makes it possible to prolong the service life of a porous electrode constituted by a sintered body of an electrode metal material and a ceramic material, and the service life of an NOx sensor element having the porous electrode. The porous electrode is produced so as to have a total pore volute of at least 0.013 ml/g and a peak pore diameter of at least 0.31 ?m as measured by mercury penetration method, by a process wherein a composition which includes the electrode material and the ceramic material and to which a vanishable solid material that vanishes by firing is formed into a thin film, which is then fired to form the sintered body which consists of the electrode material and the ceramic material and which has a multiplicity of pores formed as a result of vanishing of the vanishable solid material.

Abstract: A gas sensor element, wherein an amount of flexure in a first section extending in a longitudinal direction of the sensor element from the position 8/27 of a size of the element apart from one end of the element to the other end, is set to be greater than or equal to 1/1360 and less than or equal to 1/670 with respect to the size in the longitudinal direction of the element. The amount of flexure is a sum of a distance from a regression line to an upper side maximum displacement point and a distance from the regression line to a lower side maximum displacement point when calculating the regression line representing the relation of the position X in the longitudinal direction of the element and the displacement Y in a thickness direction from a plurality of data sets showing the relation of position X and displacement Y.

Abstract: A gas sensor element is heated at a temperature of 500° C. or higher for 15 minutes or more in a treatment atmosphere containing one or more gases selected from the gas group consisting of nitrogen (N2), oxygen (O2), carbon monoxide (CO), hydrogen (H2) and hydrocarbons (HC) and giving an air ratio of 0.80 to 1.10. In a gas sensor element to which such a treatment has been applied, a stable output is obtained without causing overshoot to an actual NOx concentration (input) even when a rapid exhaust gas change takes place.

Abstract: A gas sensor and nitrogen oxide sensor, which, when fitted to the exhaust system of an internal combustion engine, can suppress the influence of harmful substances contained in a measurement gas and can prevent the reduction in sensitivity over time. A harmful substance-trapping layer is formed at a gas inlet for introducing a to-be-measured gas from an external space into an internal space, and in a buffering space formed between diffusion resistance portions. In a trap-formed portion of a gas passage in which the harmful substance-trapping layer is formed, the measurement gas can pass in an amount of 80% or more of when the harmful substance-trapping layer is not formed in the trap-formed portion. A diffusion resistance is attained in the diffusion resistance portions; a harmful substance is trapped in the harmful substance-trapping layer; and the measurement gas is allowed to flow into a detection electrode side.

Abstract: A method of treating a gas sensor element for improving measurement characteristics thereof, including: heating the gas sensor element at a temperature of 600-1000° C. for 3-24 hours in a treatment atmosphere in which an oxygen concentration is regulated to be not higher than 0.2% and in which are included: (A) not lower than 1000 ppm of an adsorptive gas component wherein an adsorptive capable of being adsorbed on the measuring electrode is bound to oxygen; and (B) a combustible gas in an amount that can be substantially stoichiometrically oxidized by oxygen that is generated upon reduction or decomposition of the adsorptive gas component, so that the adsorptive gas component is reduced or decomposed for permitting the adsorptive in the adsorptive gas component to be adsorbed on the measuring electrode, and so that the noble metal material of the measuring electrode is reduced.

Abstract: A gas sensor contains a sensor element for detecting the concentration of a particular gas component in a measurement gas and a housing for supporting the sensor element inside, and the sensor element has a rectangular solid structure of a solid electrolyte body containing a ceramic material. In the gas sensor, four edges of the solid electrolyte body are beveled over the entire length thereof to form eleventh to fourteenth chamfered portions corresponding to the four edges.

Abstract: A gas sensor for measuring an amount of a measurement gas component, including a solid electrolyte having an internal space, a gas-introducing port for introducing measurement gas from an external space into the internal space, diffusion rate-determining means between the internal space and the gas-introducing port, and inner and outer pumping electrodes for pumping-processing oxygen contained in the measurement gas. The diffusion rate-determining means includes slits each having, when viewed in a plane substantially perpendicular to a longitudinal extension axis thereof, two dimensions, with at least one dimension of each slit being not more than 10 microns.

Abstract: A solid electrolyte body is placed on and fixed to an upper plate of a press jig such that a major surface (an upper surface) of the solid electrolyte body faces one major surface of a guide plate having a through-hole. The upper plate is rotated by a transfer mechanism to incline the solid electrolyte body in one direction, and the inclined solid electrolyte body is moved toward the other major surface of the guide plate such that a first edge of the solid electrolyte body protrudes from the through-hole. Then, a cutter is slid along the other major surface, so that the first edge is chamfered to form a first chamfered portion.

Abstract: A detecting electrode is a NOx-decomposing electrode having a certain or a high NOx-decomposing/reducing ability, which is formed on a third solid electrolyte layer for decomposing a NOx to produce oxygen. The detecting electrode contains a noble metal Pt, a material ZrO2 of the third solid electrolyte layer, and a mixture containing silica (SiO2) and alumina (Al2O3). Specifically, the detecting electrode contains 80% to 90% by weight of the Pt, 9.5% to 19.8% by weight of the ZrO2, and 0.2% to 0.5% by weight of the mixture containing silica and alumina.

Abstract: A gas sensor element including: a sensor layer in which at least one pair of electrodes are provided in a solid electrolyte for measuring an electromotive force based on a difference in an oxygen concentration between atmospheres; and a heater layer which includes a heater element with a heat generating portion and an electrically insulating layer disposed so as to enclose the heater element and which is configured to heat, by an electric current supplied to the heater element, at least a portion of the solid electrolyte at which the at least one pair of electrodes are provided, the sensor layer and the heater layer being laminated integrally on each other, wherein the electrically insulating layer contains at least one metal oxide selected from the group consisting of alkali metal oxide and alkaline earth metal oxide.

Abstract: A detecting electrode comprises a first cermet electrode layer formed directly on a solid electrolyte layer and a second cermet electrode layer formed on the first cermet electrode layer. A ratio between an alloy of Pt—Rh and ZrO2 in the first cermet electrode layer ranges from 20:80 to 50:50 by volume ratio. On the other hand, a ratio between an alloy of Pt—Rh and ZrO2 in the second cermet electrode layer ranges from 60:40 to 50:50 by volume ratio.

Abstract: A detecting electrode comprises a first cermet electrode layer formed directly on a solid electrolyte layer and a second cermet electrode layer formed on the first cermet electrode layer. The ratio between Pt and Rh in the first cermet electrode layer ranges from 100:0 to 25:75 by weight. The ratio between Pt and Rh in the second cermet electrode layer ranges from 25:75 to 0:100 by weight.

Abstract: A technology which makes it possible to prolong the service life of a porous electrode constituted by a sintered body of an electrode metal material and a ceramic material, and the service life of an NOx sensor element having the porous electrode. The porous electrode is produced so as to have a total pore volute of at least 0.013 ml/g and a peak pore diameter of at least 0.31 ?m as measured by mercury penetration method, by a process wherein a composition which includes the electrode material and the ceramic material and to which a vanishable solid material that vanishes by firing is formed into a thin film, which is then fired to form the sintered body which consists of the electrode material and the ceramic material and which has a multiplicity of pores formed as a result of vanishing of the vanishable solid material.

Abstract: A method of treating a gas sensor element for improving measurement characteristics thereof, including: heating the gas sensor element at a temperature of 600-1000° C. for 3-24 hours in a treatment atmosphere in which an oxygen concentration is regulated to be not higher than 0.2% and in which are included: (A) not lower than 1000 ppm of an adsorptive gas component wherein an adsorptive capable of being adsorbed on the measuring electrode is bound to oxygen; and (B) a combustible gas in an amount that can be substantially stoichiometrically oxidized by oxygen that is generated upon reduction or decomposition of the adsorptive gas component, so that the adsorptive gas component is reduced or decomposed for permitting the adsorptive in the adsorptive gas component to be adsorbed on the measuring electrode, and so that the noble metal material of the measuring electrode is reduced.

Abstract: A gas sensor for measuring an amount of a measurement gas component, including a solid electrolyte having an internal space, a gas-introducing port for introducing measurement gas from an external space into the internal space, diffusion rate-determining means between the internal space and the gas-introducing port, and inner and outer pumping electrodes for pumping-processing oxygen contained in the measurement gas. The diffusion rate-determining means includes slits each having, when viewed in a plane substantially perpendicular to a longitudinal extension axis thereof, two dimensions, with at least one dimension of each slit being not more than 10 microns.

Abstract: A gas sensor for measuring an amount of a measurement gas component, including a solid electrolyte having an internal space, a gas-introducing port for introducing measurement gas from an external space into the internal space, diffusion rate-determining means between the internal space and the gas-introducing port, and inner and outer pumping electrodes for pumping-processing oxygen contained in the measurement gas. The diffusion rate-determining means includes slits each having, when viewed in a plane substantially perpendicular to a longitudinal extension axis thereof, two dimensions, with at least one dimension of each slit being not more than 10 microns.