EXHAUST GAS PURIFICATION DEVICE OF ENGINE

摘要

[PROBLEMS] To provide an exhaust gas purification device using urea as a reducer capable of being properly operated, capable of stably detecting the concentration of the reducer and stably supplying the reducer in a cold season, and capable of preventing ammonia gas from being produced in a hot season. [MEANS FOR SOLVING PROBLEMS] This exhaust gas purification device of an engine (1) supplies urea water in a storage tank (20) to a reduction catalyst (3) disposed in an exhaust system. In the exhaust gas purification device, a concentration detection device (60) is installed in the storage tank (20), and the detected concentration of the urea water is adopted as basic information for controlling the supply of the urea water to the reducer. Also, a heating device to heat the reducer in the storage tank (20) and a cooling device cooling the reducer are installed to heat, desirably, the reducer near the detection part (61) of the concentration detection device and the suction port (12) of a reducer supply tube (13).