How does an automatic transmission work?
An automatic transmission (AT) is a type of transmission that automatically changes gears based on vehicle speed and engine load. An automatic transmission has several advantages, such as a smoother ride, ease of use, and the ability to downshift for better vehicle control.
Main components of automatic transmission:
* Torque Converter: Liquid coupling that transfers power from the engine to the gearbox.
* Planetary gears: Mechanisms that change the gear ratio of a gearbox.
* Gear Shifter: A device that controls the engagement and disengagement of certain planetary gears to change gears.
*Hydraulic system: Used to control the gear shifter and hydraulic clutch.
Operating principle of automatic transmission:
1. Starting the Engine: When the engine starts, the torque converter transmits power to the planetary gears.
2. Initial acceleration: During the initial acceleration phase, the gear selector engages certain planetary gears, providing a low gear ratio for maximum torque.
3. Shifting: As the vehicle speeds up and engine load increases, the shifter gradually shifts to higher ratio gears to improve efficiency.
4. Maintain Speed: When the vehicle reaches the desired speed, the gear selector selects the optimal gear to maintain by adjusting the gearbox ratio.
5. Downshifting: When additional engine acceleration or braking is required, the gear selector can shift down to a lower gear, providing a higher gear ratio.
6. Slow down and stop: When the brake pedal is pressed or the vehicle slows down, the gear selector engages a low ratio gear which creates a braking effect.
Advantages of automatic transmission:
* Smooth Ride: Automatic transmission provides smoother shifting than manual transmission.
* Ease of use: automatic transmission does not require the driver to change gears, which makes driving easier.
* Improved Handling: The ability to downshift for more torque or engine braking provides better vehicle control.
* Engine Protection: The automatic transmission protects the engine from overload by automatically shifting to lower gear ratios when overloaded.