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.
Main components of automatic transmission:
* Torque Converter: Converts engine input torque into smooth and continuous rotation.
*Planetary Gearbox: A set of gears that connect and disconnect to create different gear ratios.
*Hydraulic block: Controls gear shifting by directing pressurized fluid to the appropriate friction packs.
* Friction Packs: Groups of friction discs that lock or unlock to engage or disengage planetary gears.
* Control System: Electronic module that monitors engine, vehicle and driver inputs and makes gear shift decisions.
Gear shift process:
1. The driver presses the gas pedal: This creates hydraulic fluid pressure in the torque converter.
2. The torque converter converts the input torque: This provides smooth acceleration and prevents engine throttling.
3. The hydraulic unit directs fluid to the appropriate friction packs: This activates or deactivates certain planetary gears, changing the gear ratio.
4. Friction packs engage or disengage: This connects or disconnects the planetary gears, creating a new gear ratio.
5. The vehicle shifts to a new gear: This new gear is optimized for the current vehicle speed and engine load.
Automatic transmission types:
There are several types of automatic transmissions, including:
* Classic automatic (converter): Uses a torque converter to convert torque.
* Robotic Manual (DCT): Combines features of both manual and automatic transmissions.
* Variable Transmission (CVT): Uses tapered pulleys and a belt to smoothly change gear ratios.