Abstract: A sensor element includes an element body having formed therein a reference gas chamber in which a reference gas is to be stored; a first pump cell being configured to pump oxygen from around a first pump electrode to around a first reference electrode; a first inner lead portion configured to electrically connect a first connector electrode and the first reference electrode. The first inner lead portion has a reference gas flow region that is porous and constitutes at least part of a reference gas flow path allowing the reference gas to flow between the reference gas chamber and an outside of the element body. A limiting current A when oxygen is pumped out from around the first reference electrode to around the first pump electrode is 1.5 ?A or more.

Abstract: A gas sensor includes: an element body which is internally provided with a measurement-object gas flow portion; a first pump cell including a first inner electrode disposed in the measurement-object gas flow portion; a second pump cell including a second inner electrode disposed in the measurement-object gas flow portion; a heater; a first impedance measurer configured to measure a first impedance by applying a voltage to the first inner electrode; a second impedance measurer configured to measure a second impedance by applying a voltage to the second inner electrode; and a control apparatus configured to perform a heater control process of controlling the heater so that the first impedance reaches a target value, and a correction process of correcting, based on the second impedance, a second pump current which flows through the second pump cell or a value derived based on the second pump current.

Abstract: 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.

Abstract: A gas sensor includes: an element body which is internally provided with a measurement-object gas flow portion; a first pump cell including a first inner electrode disposed in the measurement-object gas flow portion; a second pump cell including a second inner electrode disposed in the measurement-object gas flow portion; a heater; a first impedance measurer configured to measure a first impedance by applying a voltage to the first inner electrode; a second impedance measurer configured to measure a second impedance by applying a voltage to the second inner electrode; and a control apparatus configured to perform a heater control process of controlling the heater so that the first impedance reaches a target value, and a correction process of correcting, based on the second impedance, a second pump current which flows through the second pump cell or a value derived based on the second pump current.

Abstract: A gas sensor includes: an element body which is internally provided with a measurement-object gas flow portion; a first pump cell including a first inner electrode disposed in the measurement-object gas flow portion; a second pump cell including a second inner electrode disposed in the measurement-object gas flow portion; a heater; a first impedance measurer configured to measure a first impedance by applying a voltage to the first inner electrode; a second impedance measurer configured to measure a second impedance by applying a voltage to the second inner electrode; and a control apparatus configured to perform a heater control process of controlling the heater so that the first impedance reaches a target value, and a correction process of correcting, based on the second impedance, a second pump current which flows through the second pump cell or a value derived based on the second pump current.

Abstract: Provided is a gas sensor element capable of realizing both highly accurate concentration measurement in environments where the concentration of a specific gas in a measurement target gas is high and highly accurate concentration measurement in environments where the concentration is low. A gas sensor according to one aspect of the present invention adjusts a sensor element drive temperature such that the value of cell resistance of a main pump cell is a predetermined value. Further, in the gas sensor according to one aspect of the present invention, the slope of the cell resistance of the main pump cell is larger than the slope of cell resistance of a measurement pump cell.

Abstract: Provided is a gas sensor element capable of realizing highly accurate concentration measurement in both environments where the concentration of a specific gas in a measurement target gas is high and where the concentration is low. A gas sensor according to one aspect of the present invention determines whether the concentration of a predetermined gas component in a measurement target gas is higher or lower than a predetermined concentration. If it is determined that the concentration is lower, a specific temperature that a sensor element is to reach as a result of being heated by a heater unit is set to be lower than the specific temperature set if it is determined that the concentration is higher.

Abstract: 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.