Model of automatic transmission with torque converter
Torque converter
* Is a clutch and torque converter
* Consists of a pump (turbine), turbine wheel and stator
*Transmits torque from engine to gearbox with slippage
* Limits torque transmission at low engine speeds
Planetary gearbox
* Consists of sun gear, planetary gears and ring gear
*Transmits power from the torque converter to the output shaft
* Provides different gear ratios by locking or unlocking planetary gears
Friction discs and brake bands
* Control the locking and unlocking of planetary gears
* Friction discs connect the various elements of the gearbox
* Brake bands keep the gearbox elements stationary
Valves and solenoids
* Control the flow of working fluid through the torque converter and planetary gearbox
* Activated by Electronic Control Unit (ECU)
* Adjust gear ratios and gear shifting
Electronic control unit (ECU)
* Controls the operation of the automatic transmission
* Determines gear shift timing based on input data (vehicle speed, throttle position, engine speed)
* Monitors the pressure of the working fluid and the temperature of the automatic transmission
Working fluid
*Transmits power through the torque converter and lubricates automatic transmission components
* Circulates under pressure generated by the pump
Gear shift process
1. The ECU activates the solenoid valves to supply hydraulic fluid to the corresponding friction discs or brake bands.
2. This causes the planetary gears to lock or unlock, changing the gear ratio.
3. The torque converter ensures smooth gear shifting by compensating for the speed difference between the engine and gearbox.