Abstract: A first cell includes a first electrode in a measurement gas chamber and a second electrode in a reference gas chamber. A second cell includes a third electrode in the measurement gas chamber and a fourth electrode in the reference gas chamber to cause a current therebetween that corresponds to a concentration of a specific gas component in detected gas in the measurement chamber. A controller selectively implements a normal control and a reduction control. The normal control is to apply a lower voltage to the first electrode and the second electrode to remove oxygen from the detected gas. The reduction control is to apply a higher voltage to the first electrode and the second electrode to reduce the third electrode that is oxidized. The controller prohibits implementation of the reduction control on determination that implementation of the reduction control.

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: An SCU as a control device for the gas sensor (first and second NOx sensors) includes an applied voltage switching unit for switching an applied voltage of a pump cell when a deterioration detecting function is performed, and a deterioration rate calculation unit for calculating a deterioration rate of a sensor cell based on a slope during a transient change in an output of the sensor cell according to a switching of the applied voltage by the applied voltage switching unit.

Abstract: It is to determine whether a temperature rise condition of a first cell or a second cell is satisfied based on whether a first parameter has exceeded a predetermined first threshold or a second parameter has exceeded a predetermined second threshold. After satisfaction of the temperature rise condition, it is to determine that an exhaust gas sensor is in an active state upon determination that a corresponding time condition is satisfied.

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: A microcomputer includes a voltage application unit that selectively applies a normal voltage and a removal voltage higher than the normal voltage to a first cell of the exhaust gas sensor. The first cell is configured to remove, based on the removal voltage, oxygen in an exhaust gas from an internal combustion engine. The microcomputer includes an element temperature measurement unit that measures an element temperature parameter indicative of a temperature of the first cell. The microcomputer includes a termination determination unit that determines, based on the element temperature parameter, a termination time of terminating the application of the removal voltage to the first cell by the voltage application unit.

Abstract: A first cell includes a first electrode in a measurement gas chamber and a second electrode in a reference gas chamber. A second cell includes a third electrode in the measurement gas chamber and a fourth electrode in the reference gas chamber to cause a current therebetween that corresponds to a concentration of a specific gas component in detected gas in the measurement chamber. A controller selectively implements a normal control and a reduction control. The normal control is to apply a lower voltage to the first electrode and the second electrode to remove oxygen from the detected gas. The reduction control is to apply a higher voltage to the first electrode and the second electrode to reduce the third electrode that is oxidized. The controller prohibits implementation of the reduction control on determination that implementation of the reduction control.

Abstract: It is to determine whether a temperature rise condition of a first cell or a second cell is satisfied based on whether a first parameter has exceeded a predetermined first threshold or a second parameter has exceeded a predetermined second threshold. After satisfaction of the temperature rise condition, it is to determine that an exhaust gas sensor is in an active state upon determination that a corresponding time condition is satisfied.

Abstract: A microcomputer includes a voltage application unit that selectively applies a normal voltage and a removal voltage higher than the normal voltage to a first cell of the exhaust gas sensor. The first cell is configured to remove, based on the removal voltage, oxygen in an exhaust gas from an internal combustion engine. The microcomputer includes an element temperature measurement unit that measures an element temperature parameter indicative of a temperature of the first cell. The microcomputer includes a termination determination unit that determines, based on the element temperature parameter, a termination time of terminating the application of the removal voltage to the first cell by the voltage application unit.

Abstract: An abnormality detection device for an engine system detects an abnormality in a fuel vapor pipe connected to an intake pipe of an engine at a portion upstream of a supercharger in a flow direction of intake air. The abnormality detection device includes an intake air temperature sensor and an abnormality detection portion. The intake air temperature sensor is fitted to the intake pipe on an upstream side of the supercharger in the flow direction of intake air and detects a temperature of intake air mixed with fuel vapor introduced into the intake pipe from the fuel vapor pipe. The abnormality detection portion detects an abnormality in the fuel vapor pipe according to a detection value of intake air detected by the intake air temperature sensor.

Abstract: A NOx sensor includes a pump cell, a monitor cell, and a sensor cell, and the pump cell discharges an oxygen in an exhaust gas introduced into a chamber. The sensor cell outputs a detected signal depending on a concentration of a NOx according to a gas after the oxygen is discharged. A microcomputer of a sensor control circuit temporarily changes an amount of the oxygen discharged by the pump cell, and then calculates output change amounts ?Ip, ?Is, and ?Im of the cells. The microcomputer performs a correction of the concentration of the NOx detected by the sensor cell and a deterioration diagnosis of the sensor cell, based on the output change amounts ?Ip, ?Is, and ?Im of the cells. When the sensor cell current Is is smaller than the monitor cell current Im, the microcomputer determines that the NOx sensor has an abnormality.

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 concentration detection device includes a pump cell, a sensor cell, a monitor cell, a sensor current detection unit detecting a current outputted by the sensor cell, a monitor current detection unit detecting a current outputted by the monitor cell, a voltage adjustment unit adjusting a pump cell voltage applied to the pump cell, and a sensitivity determination unit determining a gas sensitivity of at least one of the sensor cell or the monitor cell. The voltage adjustment unit changes the pump cell voltage from a target voltage into a detection voltage where the concentration of the residual oxygen supplied to the sensor cell and the monitor cell is increased. The sensitivity determination unit determines the gas sensitivity based on a detection current detected by at least one of the sensor current detection unit or the monitor current detection unit in accordance with the concentration of the residual oxygen.

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: A NOx sensor includes a pump cell, a monitor cell, and a sensor cell, and the pump cell discharges an oxygen in an exhaust gas introduced into a chamber. The sensor cell outputs a detected signal depending on a concentration of a NOx according to a gas after the oxygen is discharged. A microcomputer of a sensor control circuit temporarily changes an amount of the oxygen discharged by the pump cell, and then calculates output change amounts ?Ip, ?Is, and ?Im of the cells. The microcomputer performs a correction of the concentration of the NOx detected by the sensor cell and a deterioration diagnosis of the sensor cell, based on the output change amounts ?Ip, ?Is, and ?Im of the cells. When the sensor cell current Is is smaller than the monitor cell current Im, the microcomputer determines that the NOx sensor has an abnormality.

Abstract: A heater control device for an exhaust gas sensor disposed in an exhaust gas passage of an internal combustion engine and including a sensor element having a plurality of cells, and a heater heating the sensor element includes: a heater power control unit configured to execute a temp rising control, in which an impedance of one cell to be measured, of the plurality of cells, is detected and a temperature of the sensor element is raised until the impedance of the one cell reaches a target impedance by setting a power control value of the heater as a heating power control value. The heater power control unit continues the temp rising control until an extension period elapses that is needed for the other cell other than the one cell to reach an activation temperature after the impedance of the one cell reaches the target impedance.

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: An abnormality detection device for an engine system detects an abnormality in a fuel vapor pipe connected to an intake pipe of an engine at a portion upstream of a supercharger in a flow direction of intake air. The abnormality detection device includes an intake air temperature sensor and an abnormality detection portion. The intake air temperature sensor is fitted to the intake pipe on an upstream side of the supercharger in the flow direction of intake air and detects a temperature of intake air mixed with fuel vapor introduced into the intake pipe from the fuel vapor pipe. The abnormality detection portion detects an abnormality in the fuel vapor pipe according to a detection value of intake air detected by the intake air temperature sensor.

Abstract: A NOx sensor includes a pump cell, a monitor cell, and a sensor cell, and the pump cell discharges an oxygen in an exhaust gas introduced into a chamber. The sensor cell outputs a detected signal depending on a concentration of a NOx according to a gas after the oxygen is discharged. A microcomputer of a sensor control circuit temporarily changes an amount of the oxygen discharged by the pump cell, and then calculates output change amounts ?Ip, ?Is, and ?Im of the cells. The microcomputer performs a correction of the concentration of the NOx detected by the sensor cell and a deterioration diagnosis of the sensor cell, based on the output change amounts ?Ip, ?Is, and ?Im of the cells. When the sensor cell current Is is smaller than the monitor cell current Im, the microcomputer determines that the NOx sensor has an abnormality.

Abstract: A gas concentration detection device includes a pump cell, a sensor cell, a monitor cell, a sensor current detection unit detecting a current outputted by the sensor cell, a monitor current detection unit detecting a current outputted by the monitor cell, a voltage adjustment unit adjusting a pump cell voltage applied to the pump cell, and a sensitivity determination unit determining a gas sensitivity of at least one of the sensor cell or the monitor cell. The voltage adjustment unit changes the pump cell voltage from a target voltage into a detection voltage where the concentration of the residual oxygen supplied to the sensor cell and the monitor cell is increased. The sensitivity determination unit determines the gas sensitivity based on a detection current detected by at least one of the sensor current detection unit or the monitor current detection unit in accordance with the concentration of the residual oxygen.