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CVT System Description - Lock-Up System
Lock-Up System
The lock-up mechanism of the torque converter clutch operates in D position/mode, S position/mode, and L position/mode (without paddle shifter), at transmission fluid temperature exceeding 68 °F (20 °C). The pressurized fluid is drained from the back of the torque converter through a fluid passage, causing the torque converter clutch piston to be held against the transmission fluid pump. As this takes place, the input shaft and the drive pulley shaft rotate as the same as the engine crankshaft. Together with hydraulic control, the TCM optimizes the timing of the lock-up mechanism. When shift solenoid valve B is turned ON by the TCM, shift solenoid valve B pressure switches lock-up ON and OFF. The CVT lock-up clutch control solenoid valve controls the volume of lock-up. Torque Converter Clutch Lock-Up ON (Engaging Torque Converter Clutch)
Fluid in the chamber between the torque converter cover and the torque converter clutch piston is drained off, and fluid entering from the chamber between the pump and the stator exerts pressure through the torque converter clutch piston against the torque converter cover. The torque converter clutch piston engages with the torque converter cover; torque converter clutch lock-up ON, and the input shaft rotates at the same as the engine. Torque Converter Clutch Lock-Up OFF (Disengaging Torque Converter Clutch)
Fluid entered from the chamber between the torque converter cover and the torque converter clutch piston passes through the torque converter and goes out from the chambers between the turbine and the stator, and between the pump and the stator. As a result, the torque converter clutch piston moves away from the torque converter cover, and the torque converter clutch lock-up is released; torque converter clutch lock-up OFF. |