Torque converter lock (TCL) in Nissan automatic transmission
Torque converter lock-up is a mechanism in an automatic transmission (AT) that blocks communication between the engine and transmission at high speeds.
Target:
*Improved fuel efficiency
* Increased torque at wheels
* Reduced power loss in the torque converter
Working principle:
A torque converter is a device that transmits torque from the engine to the transmission through fluid flow. When the vehicle is started and running at low speeds, the torque converter allows the engine to rotate at a different speed than the transmission, resulting in smooth gear changes.
At higher speeds, the torque converter lock-up engages, mechanically connecting the engine and transmission. This eliminates slip in the torque converter, resulting in reduced power loss and improved vehicle performance.
Torque converter locking modes in Nissan automatic transmission:
* Full Lockup: The torque converter lockup is fully engaged at certain speeds, such as 50 km/h or above.
*Partial Lockup: The torque converter lockup is partially engaged, allowing some slippage at low speeds or under heavy load conditions.
Advantages of torque converter lock-up:
* Improved fuel efficiency by reducing power loss
*Providing higher performance and torque at the wheels
* Reducing wear on automatic transmission components by reducing slip
Note:
*Torque converter lock-up is typically controlled by the transmission’s electronic control unit (ECU).
*Some Nissan automatic transmission models may have multiple torque converter lock-up modes to optimize performance and fuel economy.