| 摘要 |
A urea quality diagnosis system capable of accurately diagnosing a quality of an aqueous urea solution in a urea tank. A concentration and a level L of an aqueous urea solution inside a urea tank 16 are detected, and the quality of the aqueous urea solution is diagnosed based on a detected value of the concentration of the aqueous urea solution when the level L is equal to or higher than a predetermined value. |
