Abstract: Each of SCUs to includes: a voltage switching unit that performs a first voltage switching to increase an oxygen concentration in a gas chamber and a second voltage switching to decrease the oxygen concentration in the gas chamber after the execution of the first voltage switching; an output change calculation unit that calculates an output change parameter indicating a change in output of the sensor cell according to the voltage switching; a concentration difference calculation unit that calculates a concentration difference parameter indicating a concentration difference in the oxygen concentration or in the concentration of the specific gas in the detection target gas between before the first voltage switching and after the second voltage switching; and a deterioration determination unit that determines a deterioration state of the sensor cell based on the output change parameter and the concentration difference parameter.

Abstract: A gas sensor includes a measurement chamber, a reference gas chamber, a first cell, and a second cell. The first cell includes a first electrode in the measurement chamber and a second electrode in the reference gas chamber. The second cell includes a third electrode in the measurement chamber and a fourth electrode in the reference gas chamber. A gas sensor detects a first current that flows between the first electrode and the second electrode, detects a second current that flows between the third electrode and the fourth electrode, calculates a concentration of a specific gas component based on a detected value of the second current, estimates a change amount of oxygen concentration in the reference gas chamber based on a detected value of the first current, and corrects the detected value of the second current based on an estimated value of the change amount of the oxygen concentration.

Abstract: In a gas sensor, a pump cell adjusts a concentration of oxygen in a gas chamber based of a pump cell supply voltage. A sensor cell detects a concentration of a specific gas in a detection target gas after the pump cell has adjusted the concentration of oxygen. In a sensor control unit, a voltage switching part adjusts the pump cell supply voltage to be supplied to the pump cell. A pump cell output control part adjusts a variation range of a pump cell output current of the pump cell before and after a voltage switching process of the pump cell supply voltage to be within a predetermined variation range. A deteriorated state detection part detects a deteriorated state ratio of the sensor cell based on variation of an output current of the sensor cell due to the voltage switching process performed by the voltage switching part.

Abstract: Each of SCUs to includes: a voltage switching unit that performs a first voltage switching to increase an oxygen concentration in a gas chamber and a second voltage switching to decrease the oxygen concentration in the gas chamber after the execution of the first voltage switching; an output change calculation unit that calculates an output change parameter indicating a change in output of the sensor cell according to the voltage switching; a concentration difference calculation unit that calculates a concentration difference parameter indicating a concentration difference in the oxygen concentration or in the concentration of the specific gas in the detection target gas between before the first voltage switching and after the second voltage switching; and a deterioration determination unit that determines a deterioration state of the sensor cell based on the output change parameter and the concentration difference parameter.

Abstract: In a control device for an exhaust gas sensor, a deterioration determination section determines whether the magnitude of a signal outputted from a second cell has exceeded a threshold to thereby determine whether a first cell has deteriorated. A threshold setting section variably sets the threshold depending on a concentration of the oxygen in the exhaust gas.

Abstract: In a gas sensor, a pump cell adjusts a concentration of oxygen in a gas chamber based of a pump cell supply voltage. A sensor cell detects a concentration of a specific gas in a detection target gas after the pump cell has adjusted the concentration of oxygen. In a sensor control unit, a voltage switching part adjusts the pump cell supply voltage to be supplied to the pump cell. A pump cell output control part adjusts a variation range of a pump cell output current of the pump cell before and after a voltage switching process of the pump cell supply voltage to be within a predetermined variation range. A deteriorated state detection part detects a deteriorated state ratio of the sensor cell based on variation of an output current of the sensor cell due to the voltage switching process performed by the voltage switching part.