Stator, Alternator

The purpose of the stator is to redirect the flow of fluid returning from the turbine to assist the engine in turning the converter pump. This redirection increases the force of the fluid driving the turbine and, as a result, multiplies torque from the engine.

At low vehicle speeds, when greater torque is required, fluid from the turbine hits the front side of the stator blades (converter multiplying torque). Because the roller clutch holds the stator from moving in that direction, fluid is redirected to assist the engine in turning the converter pump. Fluid from the converter pump then has more force to turn the turbine assembly and multiply engine torque.

As vehicle speed increases, centrifugal force changes the direction of fluid from the turbine. The direction of this fluid is such that it hits the back side of the stator blades (converter at coupling speed). This causes the roller clutch to overrun and allow the stator to rotate freely, Fluid is no longer redirected and engine torque is not being multiplied.

The pressure plate is splined to the turbine hub. It applies against the converter cover to provide a mechanical (direct drive) coupling of the engine to the transaxle. This mechanical coupling provides a more efficient transfer of engine torque to the drive wheels by eliminating the small amount of slippage that occurs in a fluid coupling. Thus, with the pressure plate (TCC) applied, the turbine assembly turns at engine speed.

To keep the pressure plate in the released position (refer to the top half of the cutaway), TCC release fluid is feed through the turbine shaft in the release circuit. This release fluid then builds up pressure to counteract the converter clutch apply fluid and releases the pressure plate away from the cover. Fluid then leaves the converter by flowing between the turbine and stator shafts, and into the cooler and lubrication circuits.

The bottom half of the torque converter cutaway shows the pressure plate in the applied position. In the applied position, converter clutch apply fluid flows between the stator shaft and converter hub to feed into the converter. This apply fluid fills the converter and applies the TCC pressure plate against the converter cover.

As the pressure plate applies, TCC disable fluid from between the converter cover and pressure plate is forced into the turbine shaft. The rate of the exhausting TCC release fluid is controlled by the converter clutch actuator to control the feel of the converter clutch. The fluid then flows back through the TCC release circuit.