| 摘要 |
PROBLEM TO BE SOLVED: To provide a urea water property determining device improved in the reliability on the decision result of the propriety of urea water.SOLUTION: An ECU 44 detects a urea water temperature Tu and a urea water concentration C from a urea water quality sensor 35, a cooling water temperature Tw from a cooling water sensor 45, and an exhaust temperature Tex from an exhaust temperature sensor 29. The ECU 44 determines the propriety of the urine water based on the urea water concentration C on condition that the urea water temperature Tu, the cooling water temperature Tw, the exhaust temperature Tex and the maximum &Dgr;Tmax of the temperature differences of those temperatures are equal to or less than a threshold value &Dgr;Tt. |
