| 摘要 |
In an embodiment of the present invention an engine (1) is equipped with: a tank (210) that stores urea water; a level sensor (250) that detects the amount of urea water remaining in the tank (210); and a urea injection valve (230) that injects the urea water in the tank (210) into an exhaust passage (26). A control device (80) determines whether a detection fault has occurred in the level sensor (250) on the basis of a first urea remainder amount detected by the level sensor (250) immediately after the engine has stopped, and an integrated value for the urea water supply amount, and a second urea remainder amount detected by the level sensor (250) after the supplying of urea water has begun. When the control device (80) determines that a detection fault has occurred with the level sensor (250), the control device sets, as the estimated value for the amount of urea in the tank (210), the value obtained by subtracting the integrated value for the urea water supply amount from the first urea remainder amount. |
