What is the working principle of an AT transmission?
2 Answers
The working principle of an AT transmission involves two turbine blades placed in a liquid-filled space, connected to the power output and input ends respectively, enabling power transfer between the two blades. The impeller on the power input end generates a strong airflow to drive the impeller on the power output end, thereby producing power in the transmission. Below are the related details: 1. The AT transmission, also known as a hydromechanical automatic transmission, features a torque converter at the front of the automatic transmission. Due to the relatively low efficiency of this setup, designers added a lock-up clutch to the torque converter to improve its efficiency. By connecting the lock-up clutch to the pump and turbine, the torque converter's performance is enhanced. 2. The AT transmission uses clutches for gear shifting, allowing uninterrupted power shifting during driving with fast and smooth gear changes. The torque converter can absorb vibrations generated by the engine during operation. However, due to the lower transmission efficiency of the torque converter, vehicles equipped with AT transmissions tend to have higher fuel consumption and higher maintenance and repair costs in the long run.
The working principle of an automatic transmission is actually quite interesting. When the engine outputs power, it is first transmitted through a torque converter, which is filled with fluid and pushes blades like a fan, enabling smooth power transfer and avoiding the jerks of manual shifting. Next, the planetary gear set comes into play—composed of a sun gear, planet gears, and a ring gear—switching between different combinations as needed to alter the gear ratio for acceleration or climbing. Finally, the hydraulic system controls oil pressure to actuate valves, while the electronic control unit (ECU) monitors real-time factors like vehicle speed and throttle position to automatically select gears. For example, when you accelerate, the system instantly downshifts to boost power; on highways, it upshifts to save fuel. Modern AT transmissions also integrate smart technologies like adaptive shifting, making driving smoother and more reliable. I find driving this car much more hassle-free, especially in traffic jams where frequent clutch use isn’t necessary.
