UREA WATER SUITABILITY DETERMINATION DEVICE

摘要

A urea water suitability determining device provided with: a concentration detection unit that detects urea water concentration and outputs detected values; a determination unit that uses said detected values to determine whether the urea water is suitable; and a temperature detection unit that detects the temperatures of a plurality of detection targets. The temperatures of the plurality of detection targets differ from each other when an engine is driving. The determination unit calculates each of the temperature differences between the temperature of a specified detection target and the temperatures of the other detection targets and commences determination of urea water suitability when determination commencement conditions are met. The determination commencement conditions include the temperature differences being within a standard range. The standard range is a range of temperature differences for which the urea water is determined to be in a quiet state.