Automatic transmission torque converter control
The torque converter is the main component of an automatic transmission (AT) that transfers power from the engine to the transmission. Torque converter control is critical to efficient and smooth transmission operation.
Operating principles of a torque converter
The torque converter consists of three main elements:
* Pump: Driven by the engine and creates a flow of working fluid.
* Turbine: Connected to the gearbox and receives torque from the pump wheel.
* Stator: Located between the pump and turbine and directs the flow of working fluid, improving the gear ratio.
Torque converter control
The torque converter is controlled by the automatic transmission control module (TCM) or integrated into the engine control module (ECM). The TCM/ECM receives signals from various sensors, including:
* Engine speed sensor
* Automatic transmission input shaft speed sensor
* Automatic transmission output shaft speed sensor
* Throttle Position Sensor
Based on these signals, the TCM/ECM determines:
*Speed ratio between pump and turbine
* Locking moment
*Need to change gears
Blocking adjustment
The torque converter locks up when engine and gearbox speeds are close. This eliminates slipping, improving efficiency and fuel economy. The TCM/ECM controls torque converter lockup using the lockup solenoid.
Shifting gears
The torque converter is also involved in gear shifting. When the TCM/ECM detects the need to change gear, it applies the brake band or clutch to smoothly transition between gears.
Types of torque converter control
There are different types of torque converter control, including:
* Simultaneous control: TCM/ECM controls locking and shifting simultaneously.
*Sequential Control: The TCM/ECM controls locking and shifting separately, providing better fuel economy and a smoother ride.
Benefits of efficient torque converter control
Effective torque converter control provides the following benefits:
* Improved fuel economy
* Improved gear shift smoothness
*Optimal transmission performance
* Increased transmission life