The first electrochemical oxygen sensor includes: a positive/negative electrode; and an electrolyte solution, the electrochemical oxygen sensor further including: a separation membrane for limiting an amount of oxygen supplied to the positive electrode, and a resistance element for connecting the positive electrode and the negative electrode. In one embodiment, a value of current flowing through the resistance element is 7 μA or more in an atmosphere of 50% relative humidity at 25° C. and 1 atm, and a resistance value of the resistance element is set at 1050 Ω or less. In another embodiment, a value of current flowing through the resistance element is 4 μA or more in an atmosphere of 50% relative humidity at 25° C. and 1 atm, and a resistance value of the resistance element is set so that the output voltage between both ends of the resistance element falls within a range from 4 to 9.5 mV.

A gas sensor includes a gas sensor element for detecting a specific gas concentration in measured gas. The gas sensor element includes a solid electrolyte, a measured gas side electrode into which measured gas is introduced through a porous diffusion resistance layer, a reference gas side electrode facing a reference gas chamber, and a diffusion space portion between the porous diffusion resistance layer and the measured gas side electrode. The porous diffusion resistance layer has a measured gas inlet opened to an element outer surface and a measured gas outlet opened to the diffusion space portion. A relationship between a distance between the inlet and the outlet and a distance between the outlet and the measured gas side electrode is expressed by 0<L1/(L1+L2)<0.4.

A ceramic heater is provided in an electronic component, and by supplying electrical current thereto, a heat generating portion thereof is heated to a temperature of greater than or equal to 700[° C.] and less than 950[° C.]. An energizing current waveform of the electrical current to the heat generating portion is a pulse waveform, and a product of a pulse voltage Vp [V] and a period T [ms] of the pulse waveform is less than or equal to 600 [V.Math.ms].

The invention relates to a solid electrolyte including partially stabilized zirconia, a producing method thereof, and a gas sensor including a solid electrolyte. The partially stabilized zirconia includes crystal particles, the crystal particles include mixed phase particles each having a high-concentration phase and a low-concentration phase, the high-concentration phase being defined such that a concentration of the stabilizer is 4.7 mol % or more, the low-concentration phase being defined as a concentration of the stabilizer is less than 4.7 mol %.

Some embodiments of the present invention provide solid oxide cells and components thereof having a metal oxide electrolyte that exhibits enhanced ionic conductivity. Certain of those embodiments have two materials, at least one of which is a metal oxide, disposed so that at least some interfaces between the domains of the materials orient in a direction substantially parallel to the desired ionic conductivity.

A gas sensor includes an element body having an oxygen ion conductive solid electrolyte layer and internally provided with a measurement-object gas flow section that introduces a measurement-object gas and allows the gas to flow; a measurement-object gas-side electrode disposed in a portion of the element body, the portion being exposed to the measurement-object gas; and a reference electrode disposed inside of the element body. Let A [μA] be a limiting current when oxygen is pumped from the surroundings of the measurement-object gas-side electrode to the surroundings of the reference electrode with the measurement-object gas introduction section, and B [μA] be a limiting current when oxygen is pumped from the surroundings of the reference electrode to the surroundings of the measurement-object gas-side electrode with the reference gas introduction section, then a ratio A/B is greater than or equal to 0.005.

A gas sensor having a reliable measurement accuracy for specific gases even if a pump electrode is heated and a method for manufacturing the same are provided. The gas sensor is provided with a measurement target gas chamber, a reference gas chamber, a solid electrolyte, a pump electrode, a sensor electrode, a reference electrode and a heater. The pump electrode includes Pt, Au and an aggregate. After the gas sensor has been manufactured, in a state that the pump electrode has not been heated to an activation temperature of the solid electrolyte yet, in the pump electrode, a pore is 5.2 vol % or less, a surface roughness Ra is 0.5 μm to 9.1 μm, and a content ratio of the aggregate 31 is 4.9 vol % or more.

A gas sensor includes an element body, a pump cell, an impedance measurer, and a calculation unit. The pump cell has an inner electrode disposed in a measurement-object gas flow section of the element body, and an outer electrode disposed outside an element body to come into contact with a measurement-object gas, the pump cell being configured to adjust an oxygen concentration in a vicinity of the inner electrode. The impedance measurer performs first measurement to measure a first impedance by applying a voltage having a first frequency to the pump cell, and second measurement to measure a second impedance by applying a voltage having a second frequency higher than the first frequency to the pump cell. The calculation unit calculates the reaction resistance index correlated with the reaction resistance of the pump cell, based on the first and second impedances.

A gas concentration detection device for detecting a gas concentration using a limiting current type gas concentration sensor. In an application voltage line set to pass through a plurality of limiting current regions for different values of gas concentration, the voltage set by the application voltage line is an identical first voltage value used when an air/fuel ratio corresponding to the gas concentration is in a predetermined first range, is an identical second voltage value different from the first voltage value used when the air/fuel ratio is in a second range adjacent to the first range, and the first voltage value and the second voltage value are switched between the first range and the second range.

A gas sensor element comprises a solid electrolyte layer; a detection electrode provided on one surface of the solid electrolyte layer; a reference electrode provided on another surface of the solid electrolyte layer; a first layer provided on a side where the other surface of the solid electrolyte layer is present, and having a reference gas flow path; and a heater layer provided on a side opposite to a side where the solid electrolyte layer is provided. In the gas sensor element, an introduction flow path is formed as a flow path for guiding the reference gas from outer surfaces of the gas sensor element to the reference gas flow path. The introduction flow path has an opening provided at an outer surface that is perpendicular to a stacking direction of the gas sensor element and is provided on a side opposite to the heater layer.