The SCR temperature sensor is used to monitor the selective catalytic reduction device (SCR) to achieve maximum catalytic efficiency. Its function is to feedback the temperature of the urea solution in real time to confirm whether the heater is working normally, and to ensure the normal operation of the SCR system and the safety of the vehicle.
In the case of low temperature (-11 ℃), the urea aqueous solution will freeze. In order to ensure the normal operation of the SCR system under lower ambient temperature conditions and prevent the urea solution from freezing, it needs to be solved by heating measures. When the vehicle is running in a low-temperature environment, if the temperature measured by the urea tank temperature sensor is lower than the specified value (generally set to 0 ℃), the engine electronic control unit will issue a command to turn on the engine to the urea tank coolant circuit The valve uses the engine's coolant to heat the urea tank to prevent the urea solution from freezing or thawing the frozen urea solution to ensure the normal operation of the post-treatment system. When the temperature of the urea solution rises to the specified value (generally set to about 7 ℃), the control solenoid valve is opened to prevent the urea solution from overheating.