All in all, the function of the thermostat is to keep the engine from overcooling. For example, after the engine is working normally, if there is no thermostat when driving in winter, the temperature of the engine may be too low. At this time, the engine needs to temporarily stop the water circulation to ensure that the engine temperature will not be too low.
The main thermostat used is a wax type thermostat. When the cooling temperature is lower than the specified value, the refined paraffin wax in the temperature sensing body of the thermostat is solid, and the thermostat valve closes the gap between the engine and the radiator under the action of a spring. The coolant returns to the engine through the water pump to carry out a small cycle in the engine. When the temperature of the cooling liquid reaches the specified value, the paraffin wax begins to melt and gradually becomes liquid, and the volume increases accordingly and compresses the rubber tube to make it shrink. When the rubber tube shrinks, an upward thrust is applied to the push rod, and the push rod has a downward reverse thrust to the valve to open the valve. At this time, the coolant passes through the radiator and thermostat valve, and then flows back to the engine through the water pump for a large cycle. Most of the thermostats are arranged in the water outlet pipeline of the cylinder head. The advantage of this is that the structure is simple and it is easy to eliminate the air bubbles in the cooling system; the disadvantage is that the thermostat is often opened and closed during work, resulting in oscillation.
