What is viscous coupling in AWD?
The viscous coupling is often found in all-wheel-drive vehicles. It is commonly used to link the back wheels to the front wheels so that when one set of wheels starts to slip, torque will be transferred to the other set. Under normal conditions, both sets of plates and the viscous fluid spin at the same speed.
How does a viscous coupling differential work?
viscous coupling integrated into the center differential Central differential distributes power to all wheels and lets them turn at different speeds while cornering. When excessive wheelspin occurs on one of the axles, viscous coupling locks the differential and equalizes the speeds of both axles.
What does a viscous coupling?
A viscous coupling is a mechanical device which transfers torque and rotation by the medium of a viscous fluid.
What is the purpose of a viscous coupler?
What fluid is used in a viscous coupling?
silicone
The drum is filled with a dilatant fluid, often silicone-based, to about 80% by volume.
How does a viscous differential work?
Viscous LSD’s work in a very similar way to an open differential, with the difference being a clutch pack attached to one of the drive shafts. When one wheel spins the viscous fluid heats up and gives extra resistance, this has the effect of slowing the spinning wheel down, and diverting torque to the wheel with grip.
How does a viscous coupling work in a Volvo?
However, before the switchover to the Haldex system in 2003, Volvo used a viscous coupling designed by GKN Driveline to transfer torque to the rear axles. A viscous coupling is an assembly of closely spaced plates bathed in a dilatant fluid (essentially just a thickening fluid). This viscous coupling links the front and rear drivetrains.
How does a viscous coupling AWD system work?
A viscous coupling is an assembly of closely spaced plates bathed in a dilatant fluid (essentially just a thickening fluid). This viscous coupling links the front and rear drivetrains. The first-generation Haldex AWD system is the first reactive hydraulic AWD system produced by Haldex Traction.
How does the AWD system work in a Volvo?
This means the AWD system relies on wheelspin to activate the torque transfer from front to rear wheels. It uses a mechanical pump connected to the input and output shaft of the Haldex clutch assembly. Normal driving with ample traction means the car is nearly entirely front wheel drive.
How does VW Golf MkII Syncro reduce viscous coupling?
In an attempt to reduce the coupling’s activation time, VW Golf MkII Syncro always transfers 5% of torque to rear wheels (this is achieved by rear driveshaft rotating slower than front driveshaft in normal conditions, causing viscous fluid warm-up and slight solidification).