The torque converter is located at the front end of the hydraulic automatic transmission and mounted on the engine's flywheel. Its function is similar to that of a clutch in a car. It can automatically and steplessly adjust the transmission ratio and torque ratio within a certain range according to changes in the vehicle's driving resistance, featuring a certain deceleration and torque multiplication effect. Currently, the three-element locked comprehensive torque converter composed of an impeller, a turbine, and a stator is widely adopted.
The impeller is integrated with the torque converter housing and serves as the driving element. The turbine is connected to the output shaft via splines and acts as the driven element. The stator is positioned between the impeller and the turbine, fixed to the transmission housing through an overrunning clutch and a stator sleeve. After the engine starts, the crankshaft drives the impeller to rotate via the flywheel. The centrifugal force generated by rotation causes the working fluid between the impeller blades to be thrown from the inner edge to the outer edge along the blades. This part of the working fluid has both a circumferential component of velocity that rotates with the impeller and an axial component of velocity that rushes toward the turbine. The working fluid impacts the turbine blades, driving the turbine to rotate in the same direction as the impeller. The velocity of the working fluid flowing out of the turbine can be regarded as the resultant of the tangential velocity of the working fluid flowing out relative to the turbine blade surface and the circumferential velocity of the working fluid rotating with the turbine. When the turbine speed is relatively low, the working fluid flowing out of the turbine is in the reverse direction, impacting the front surface of the stator blades. Since the stator is restricted by the overrunning clutch from rotating in the reverse direction, the stator blades redirect the reverse-flowing working fluid to push the impeller blades forward, promoting the rotation of the impeller and thereby increasing the torque acting on the turbine.
