An electronically controlled automatic transmission (ATT), also known as an electronic automatic transmission (EAT), is a type of automatic transmission that uses an electronic control unit (ECU) to control gear shifting instead of a traditional mechanical or hydraulic system.
Working principle:
1. Sensors: Speed, throttle position, temperature and pressure sensors measure vehicle operating conditions.
2. ECU (Electronic Control Unit): The ECU collects data from sensors and uses built-in software to determine the optimal gear shift point.
3. Solenoids: Based on ECU calculations, electronic solenoids control the flow of transmission fluid in the transmission, activating and deactivating the various clutch packs.
4. Gear Shift: Solenoids regulate fluid pressure to shift gears smoothly and efficiently.
Advantages:
* Increased comfort: Electronic control provides smooth gear changes, reduces hesitation and improves driving comfort.
* Efficiency: Optimized shift points improve fuel economy and reduce emissions.
* Adaptability: The ECU can adapt to driving style and driving conditions, adjusting the gear shift schedule to improve performance.
*Customization options: The electronic control allows for customization of shift parameters, giving drivers the ability to change the sportiness or smoothness of the ride.
* Diagnostics: The electronic control system allows you to easily diagnose transmission problems, helping you quickly resolve problems.
Flaws:
*Higher Cost: Electronic automatic transmissions are more expensive to produce than traditional hydraulic ones.
* Difficulty of Repair: Due to the electronic components, repairing these transmissions can be more difficult and costly.
*Limited Reliability: Electronic control systems may fail, causing transmission problems.
Examples:
* Toyota Multi-Mode Transmission (CVT)
*Ford PowerShift
* Volkswagen DSG (Direct Shift Gearbox)
* GM Hydra-Matic 8L90