Drive Fan is a fluid clutch to adequately control rotation frequency of the fan for engine cooling. Temperature-sensitive bi-metal, which detects air temperature passing through the radiator, controls working silicone oil volume in the drive so that fan rotation frequency is kept adequately in controlled manner. In a viscous drive, the main shaft turns at RPM proportional to the engine speed, while the drive housing attached to the engine fan maintains a separate speed, set by the electronic engine control module. In other words: The fan clutch speed is independent from the engine’s RPM.
Mechanical fans are driven by the engine’s rotation. They are bolted to the water pump and turned by a belt. There are 2 types of mechanical fans, clutch fans and flex fans. Clutch Fans have fixed blades. Fan clutches are designed to engage the fan and make sure it turns when the valve opens. They push the Piston Friction Disc (PFD) against the friction material while also sending air pressure to overcome the spring.
Unlike conventional fan motors, a variable speed blower motor runs at different speeds to precisely control the flow of heated or cooled air throughout your home. Better airflow control means a better balance of temperature and humidity.
