02
Apr
This allows the engine to operate more efficiently by removing the load that the fan places on it. I also heat the bimetal spring to show how that works.
Detailed animations show internal components.
How does a clutch fan work. The fan clutch is design with either an electronic controlled activation device or a temperature sensitive spring at the front of the clutch to tell the clutch when to turn on and engage to the input shaft. When the clutch engages the fan blade starts to operate pulling air though the radiator to cool the engine down. A fan clutch is a viscous material mixed with a bi-metallic sensory system that is comparable to that in a thermostat.
The viscosity of the fan clutch allows internal friction to occur by moving the molecules against one another thereby causing the fluid to defy flow. A fan clutch is a temperature-controlled coupling between the water pump shaft and the fan which allows the fan to be operational at low speeds and disconnected at higher speeds. This allows the engine to operate more efficiently by removing the load that the fan places on it.
So how does it work. It really depends on the style of fan clutch you choose. A fan clutch is a thermostatic engine cooling fan that can freewheel at low temperatures when cooling is not needed allowing the engine to warm up faster relieving unnecessary load on the engine.
As temperatures increase the clutch engages so that the fan is driven by engine power and moves air to cool the engine. The fluid in the clutch gets thicker as it heats up causing the fan to spin faster to catch up with the engine rotation. When the car is cold the fluid in the clutch remains cold and the fan spins slowly allowing the engine to quickly warm up to its proper operating temperature.
A torque-limiting fan clutch reacts to engine speed. A centrifugal valve opens to allow the flow of heavy silicone fluid locking the fan blades to the pulley. At idle and low engine speeds this fan clutch is fully engaged gradually disengaging as engine speed increases.
Depending on the application it may freewheel above 2500 to 3000 rpm. Viscous Fan Clutch Viscous fan clutches are belt driven and found on many older rear-wheel-drive passenger cars. They contain a drive and driven plate with annular grooves that fill with a thick viscous silicon fluid.
These fans are needed at slow speeds typically below 35 mph and at idle. A fan clutch is the assembly that your engine cooling fan rides on and that tells the fan when to turn on and off. A central core which locks and unlocks based on the temperature allows the fan to spin with the engine crankshaft or freewheel on its own.
When a fan clutch binds or locks up the air passing through it can produce a gentle roar thats audible from inside the cabin of the vehicle. The next time youre driving about 50 mph 80 kmh or higher take note of how the fan sounds. Activity thats louder than normal may indicate binding.
The fan clutch is an automatic device that is often used in a vehicles cooling system. So when the engine is cool or even when it is at a normal operating temperature the fan clutch will partially disengage the engines radiator cooling fan which is mechanically driven. Learn what makes a viscous fan clutch operate.
Detailed animations show internal components. How Clutch Fans Work Both thermal and nonthermal clutches are filled with silicone based oil. The low viscosity oil channels energy to the fan by transferring centrifugal hydraulic pressure from the clutch housing cavity to fluid coupling teeth and the clutch plate.
This is an exploded diagram in the physical form with an explanation of how a fan clutch works. I also heat the bimetal spring to show how that works. The fan clutch is a thermostatic device which means it operates based off temperature and is usually mounted on the water pump or another belt driven pulley.
The fan clutch will spin loosely until the temperature reaches a certain level at which point the fan clutch will fully engage so that the fan can work at maximum efficiency. There are two main types of mechanical fans. Clutch fans and flex fans.
Clutch fans are controlled by a thermostat and utilize a clutch to engage or disengage the fan at a specified engine speed or temperature. However the fans clutch never fully disengagesit keeps spinning at about 30 percent of the water pump speed at all times. The fan clutch is a thermostatic device which means it operates based off temperature and is usually mounted on the water pump or another belt driven pulley.
The fan clutch will spin loosely. It helps to note that the fan clutch comprises several internal components that are integral in its functioning. It has clutch plates as well as a coupling.
The latter fills with oil and has a valve that controls the flow of oil between two compartments. One acts as a holding area while the other directs to the clutch. A manual fan is connected to the engine drive pulleys and is controlled by a thermo fan clutch which senses radiator heat and engages when the engine is running at higher temperatures.
These thermo reactive clutches are constructed to freewheel when not in use and become connected using a silicone grease which expands when heated.