Automatic transmission electronic control circuit
1. Sensors
*Car speed sensor
* Engine speed sensor
* Gear selector position sensor
* Throttle Position Sensor
*Transmission fluid temperature sensor
2. Electronic control unit (ECU)
* Receives data from sensors and determines when to shift gears
* Controls solenoids for gear shifting
* Regulates pressure in the transmission system
* Protects transmission from damage
3. Solenoids
* Solenoid valves that control the flow of transmission fluid
* Used to change gears, engage torque converter lock-up and control transmission pressure
4. Torque converter
* Fluid coupling which ensures smooth power transfer from engine to transmission
*Controlled by torque converter lockup solenoid
5. Planetary gearbox
* A set of gears and planetary sets that provide different gear ratios for forward and reverse movement
6. Transmission fluid
* Provides lubrication, cooling and hydraulic control for the gear system
7. Input shaft
* Connected to the engine via a torque converter
*Drives other internal drivetrain components
8. Output shaft
* Connects to the drive wheels of the car and transmits power from the engine to them
How the system works:
1. Sensors collect data about the operation of the engine, vehicle and transmission.
2. The ECU analyzes the data and determines when to shift gears.
3. The ECU activates the solenoids, which direct transmission fluid to the appropriate channels.
4. Transmission fluid drives the planetary gearbox, resulting in gear changes.
5. The torque converter transfers power from the engine to the transmission for smooth gear shifting.
6. Transmission fluid provides lubrication, cooling and hydraulic control to the transmission system.