The stator redirects the fluid coming from the turbine so that it re-enters the impeller travelling in the same direction as impeller rotation. This provides torque multiplication.
Rotary flow, vortex flow and spiral flow are terms which describe fluid flow paths in the torque converter. These paths are dependent on operating conditions.
In a lock-up converter, the impeller and turbine are locked together when operating conditions are suitable to provide a one to one drive from the engine to the transmission input shaft.
The stator one way clutch prevents the stator from turning in the opposite direction to engine rotation during torque multiplication. It allows the stator to rotate with the impeller and turbine when coupling point is reached.
