The torque converter consists of three parts: pump (or leading part), turbines (driven part) and reactor (stator). The pump blades are made in the torque converter housing. The internal cavity of the torque converter is filled with oil. A turbine and a reactor are also located in the torque converter housing. The torque converter housing is attached to the engine flywheel.
With the engine running, the pump rotates at crankshaft speed and operates as a centrifugal pump. Oil is supplied to the central part of the pump and, under the action of centrifugal force, is ejected between the blades.
The shape of the cups and pump blades are chosen in such a way that the oil is ejected to the turbine blades in a clockwise direction, causing it to rotate. The pump and the turbine of the torque converter are not mechanically interconnected and the rotation of the pump is transmitted to the turbine only due to the energy of the oil. The turbine is splined to the turbine's hollow shaft, which transmits torque through a sprocket and chain.
When the engine is idling, the speed of the torque converter pump is low. The energy of the oil leaving the pump, and therefore the torque transmitted to the turbine, is extremely low. This ensures that the engine is idling, while the car may slightly «lead». As the accelerator pedal is depressed, the speed of the torque converter pump increases and the energy of the oil ejected onto the turbine blades, which creates torque.
After power is transferred to the turbine, oil is discharged along its blades in a counterclockwise direction.
Since the energy absorbed by the turbine has been sufficient to change the direction of oil circulation, the turbine increases the torque.
If the anti-clockwise ejected oil could directly enter the torque converter pump. it would come into contact with the inner surface of the pump blades in the direction opposite to its rotation, which would lead to a complete loss of torque gain. To eliminate this, a reactor is installed between the pump and the torque converter turbine (stator).
The reactor gives the oil returned to the pump the same direction of rotation as the pump.
Since the oil exiting the reactor does not interfere with the rotation of the pump, the motor torque is added to the torque of the oil as it passes through the pump, and this cycle is restarted each time.
The oil returned to the turbine tends to rotate the stator clockwise. The reactor is mounted on a freewheel and can only rotate clockwise. Therefore, when the pump rotates at low speed, the oil ejected from the turbine acts on the reactor blades, tending to turn it counterclockwise, and blocks the freewheel, which prevents the reactor from turning.
As the speed of rotation of the turbine increases, the direction of circulation of the oil ejected from it changes, which acts on the reactor blades in a clockwise direction. As the reactor blocks the passage of oil to the pump, the freewheel is released, allowing the stator to rotate freely on the shaft. The reactor ceases to participate in the process of increasing torque in the torque converter. Since the pump and turbine rotate at the same speed or in a 1:1 ratio, the torque converter starts to work as a fluid coupling.
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