Torque Converter
The converter consists of the impeller, the turbine wheel, the reaction member (stator) and 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, where is direction of flow is deflected. At the hub, the oil leaves the turbine and reaches the reaction member (stator), where it is once again deflected so that it 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 turbine torque and torque is referred to as torque multiplication.
The greater the difference is speed between the pump and turbine, the greater the torque multiplication; it is at its highest when the turbine is at a standstill. The higher the speed of the turbine, the lower the torque multiplication.
When the turbine speed reaches about 85% of the pump speed, torque multiplication = 1, i.e. the turbine torque 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 over-come. From this point onwards, the converter acts as a straightforward fluid coupling.