| 摘要 |
PROBLEM TO BE SOLVED: To provide a gas concentration detector capable of a reduction in gas sensitivity resulting from the degradation of a NOx sensor without deteriorating exhaust emissions.SOLUTION: An ECU 10 serving as a gas concentration detector comprises: a voltage adjustment unit 104 reducing a pump cell voltage applied to a pump cell 246 from a target voltage to a detection voltage, and increasing a residual oxygen concentration supplied to a sensor cell 248 and a monitor cell 249; and a sensitivity determination unit 106 determining the gas sensitivity of the sensor cell 248 and the monitor cell 249 on the basis of a detected current detected by at least one of a sensor current detection unit 101 and a monitor current detection unit 102 in response to the increased residual oxygen concentration.SELECTED DRAWING: Figure 2 |
