Automatic transmission (AT)
An automatic transmission is a type of transmission that automatically changes gears based on driving conditions (speed, load, and throttle position). It is designed to make driving easier by eliminating the need for the driver to manually change gears.
Main components of automatic transmission
* Torque Converter: Uses hydraulic fluid to transfer power from the engine to the transmission, providing smooth gear changes.
* Planetary gear: Consists of gears and planetary gears that change the transmission ratio.
*Hydraulic control unit: Controls the flow of hydraulic fluid for gear shifting and clutch operation.
* Electrical control unit: Monitors driving conditions and sends signals to the hydraulic control unit to change gears.
Operating principle of automatic transmission
1. The driver selects a gear (P, R, N, D, etc.).
2. The hydraulic control unit directs hydraulic fluid to the corresponding planetary gear, locking or unlocking the gears.
3. The transmission ratio changes, resulting in a change in vehicle speed.
4. When driving conditions change, the electrical control unit sends a signal to the hydraulic control unit to shift to the appropriate gear.
5. The hydraulic control unit redirects the flow of hydraulic fluid, changing gears and ensuring smooth transition.
Advantage of automatic transmission
* Ease of driving
* Smooth gear shifting
* Improved handling in some conditions (such as slippery surfaces)
Disadvantages of automatic transmission
*Higher maintenance cost
*Reduced fuel efficiency compared to manual transmission
* Less control over the car for experienced drivers