Liquid freezing point identification device, liquid storage tank freezing prevention device using the same, and automobile exhaust gas reduction device

摘要

Accurately identifies the concentration of the urea aqueous solution in the urea aqueous solution tank, and based on the temperature measured by the temperature sensor, accurately grasps the freezing point at the concentration based on the state diagram of the urea aqueous solution (saturated solubility curve) . A solidification prevention device for preventing solidification of the liquid storage tank or melting all or part of the solidified liquid, a liquid temperature sensor for identifying the temperature of the stored liquid, and a physical quantity for measuring the physical quantity of the stored liquid A liquid freezing point identifying device configured to identify a freezing point of the stored liquid in the liquid storage tank by measuring a physical quantity corresponding to the stored liquid using the physical quantity measuring sensor, and a liquid sensor There is provided a heating device for heating the stored liquid in the liquid storage tank based on the result of identifying the freezing point of the stored liquid of the freezing point identifying device and the temperature of the stored liquid by the liquid temperature sensor.