| 摘要 |
A diagnostic device for a urea water supply system, the device having a sensor that detects urea water concentration. The device is provided with: an acquisition unit that acquires detected values from the sensor; a calculation unit that calculates the rate (·) at which NOx is purified by a selective reduction catalyst; and a diagnostic unit that diagnoses the state of a urea water supply system. A first condition is that the purification rate (·) calculated by the calculation unit is at or above a standard purification rate, and a second condition is that a detected value (Cur) acquired by the acquisition unit is at or above a standard concentration. When only one of the first condition and the second condition is met, the diagnostic device diagnoses an abnormality in the sensor. |
