During the driving of the car, due to changes in environmental conditions and operating conditions, the thermal condition of the engine is also changing. Therefore, the cooling intensity of the engine must be adjusted at any time. For example, in the hot summer, when the engine is working at low speed and heavy load, and the temperature of the coolant is high, the fan should rotate at a high speed to increase the cooling air volume and enhance the heat dissipation capacity of the radiator; while in the cold winter, the coolant temperature is relatively high. When it is low, or when the car is driving at high speed with strong oncoming wind blowing over the radiator, it becomes meaningless for the fan to continue to work. It not only consumes engine power in vain, but also produces a lot of noise. Tests have proved that the water-cooling system requires fans to work only 25% of the time, and the fans need to work for a shorter period of time in winter. Therefore, adjusting the cooling intensity of the engine at any time according to the thermal condition of the engine can reduce noise and power loss. Installing a silicone oil fan clutch between the fan pulley and the cooling fan is one of the methods to achieve this adjustment.