Fluid Couplings and Torque Converters

Introduction Engine and Transmission needs to be automatically coupled and uncoupled Uses Torque Converter to multiply torque and transmit power Components Impeller Turbine Stator

Fluid Coupling Fluid travels either in a rotary or vortex motion

Impeller turns Tubine Turbine Impeller

Fluid drives turbine at an angle

Difference in speed creates a turbulence

Components Flexplate drives T.C. Torque Converter Hub drives oil pump Impeller drives Turbine Turbine drives input shaft Input shaft drives Clutch Hub

Vanes are curved to accelerate fluid flow

Rear Wheel Drive Input shaft directly connects to turbine with splines Input shaft is usually hollow for lock up operation

Front Wheel Drive Turbine Shaft drives Input Shaft

Stator Operation Stator assembly mounts on One-way clutch. Stator multiplies torque At 90% speed ratio, the stator rotates same speed as turbine and impeller and “coupling phase” occurs.

Early Converter were repairable Older converters had drains

One Way Clutch

Chrysler TCC Release pressure disengages clutch plate Venting pressure causes lock up

Ford Lock Up Clutch Piston hub splines directly to the turbine

GM TCC First used in 1980, Applied by TCC Solenoid

Vane curvature controls amount of multiplication

Converter Operation Stator redirects fluid back into impeller to multiply force More torque happens at lower rpms. At higher rpm, components equalize