| 摘要 |
PROBLEM TO BE SOLVED: To provide a failure determination device and a failure determination method for a NOx sensor capable of shortening the period, for which the supply of a reducer is stopped.SOLUTION: An ECU 44 decides it on the basis of a DPF temperature input from a DPF temperature sensor 26 whether or not a DPF 24 is in a regeneration processing. The ECU 44 outputs a stop signal to an injector 30 during the reproduction of the DPF 24 thereby to stop the supply of urea water. The ECU 44 decides the presence or absence of the trouble of a downstream NOx sensor 42 on the basis of the detection value of an upstream NOx sensor 28 and the detection value of the downstream NOx sensor 42, if it decides that a predetermined quantity of NOx has flown after the output of the stop signal to a selective reduction type catalyst 36. |
