Working principle of thermostat

A thermostat  is a valve that controls the flow path of a coolant. It is an automatic temperature regulating device, usually containing a temperature-sensing component, that turns on or off the flow of air, gas, or liquid by thermal expansion or contraction. It is installed in the engine water circuit to control the engine temperature and consists of a valve body, spring, piston and seal. When the engine is running, the coolant flows to the thermostat. If the engine water temperature is low, the valve is closed, allowing the coolant to circulate in the engine, a process called small circulation, until the correct temperature is reached (generally 70-90 degrees Celsius). When the temperature reaches a set point, the valve opens to allow the coolant to flow through the radiator and reduce the temperature, a process called large circulation to maintain a stable engine operating temperature.

The operating principle of the thermostat is based on sensing the coolant temperature to control the opening and closing of its own valve. It controls the thermostat opening according to the water temperature, when the engine is in the cold state, the thermostat valve is closed, and the coolant does not flow through the water tank, so that the engine can quickly reach the hot state. When the coolant reaches the temperature, the thermostat valve opens and the coolant enters the water tank to dissipate heat.

The thermostat is divided into mechanical and electronic two categories, their implementation principle is the same, the difference is that the electronic thermostat pull heat trigger mechanism is different. The mechanical thermostat realizes the opening and closing of the valve through the thermal expansion and cold contraction characteristics of the paraffin, while the electronic thermostat controls the expansion and contraction of the paraffin through electronic heating.