Torque Converter: Notes

The converter consists of the following components:

• The impeller
• The turbine wheel
• The reaction member: stator
• The oil to transmit torque

The impeller, which is driven by the engine, causes the oil in the converter to flow in a circular pattern. This oil flow meets the turbine wheel, which deflects the direction of flow. At the hub the oil leaves the turbine and reaches the reactor member, or stator, which again deflects the oil so that the oil reaches the impeller at the correct angle of flow.

The reversal effect generates movement in the stator. The reaction torque then amplifies the turbine torque.

The ratio between the turbine torque and the torque is called torque multiplication.

The greater the difference in speed between the pump and the turbine, the greater the torque multiplication. The turbine is at a standstill when the torque multiplication is highest. The higher the speed of the turbine, the lower the torque multiplication.

When the turbine speed reaches about 85 percent of the pump speed, torque multiplication is equal to 1, that is, the turbine torque is equivalent to pump torque.

The stator, which bears against the housing via the freewheel, is then rotating freely in the oil flow, and the freewheel is overcome. From this point onwards, the converter acts as a straightforward fluid coupling.

The illustration identifies the following components in the space behind the lock-up clutch piston:

1. Friction Lining
2. Lock-up Clutch Piston
3. Converter Cover
4. Turbine Wheel
5. Impeller
6. Stator
7. Turbine Hub
8. Torque Converter Impeller Hub