Line Pressure Control

LINE PRESSURE CONTROL
^ If the engine control unit sends the input torque signal equivalent to the engine driving force to the A/T control unit (TCM), the A/T control unit (TCM) controls line pressure solenoid.
^ This line pressure solenoid controls the pressure regulator valve as the signal pressure and adjusts the pressure of the operating oil discharged from the oil pump to the line pressure most appropriate to the driving plate.





LINE PRESSURE SYSTEM DIAGRAM

LINE PRESSURE CONTROL BASED ON LINE PRESSURE CHARACTERISTIC PATTERN OF A/T CONTROL UNIT (TCM)
^ A/T control unit (TCM) has stored in memory a number of patterns for the optimum line pressure characteristics according to driving conditions.
^ In order to obtain the most appropriate line pressure characteristic to meet the current driving state, the TCM controls the line pressure solenoid current valve and thus controls the line pressure,





Normal line pressure control.
Each clutch is adjusted to the necessary pressure to match the engine drive force.





Back-up control (Engine brake)
Line pressure according to speed is set during shift down by select operation while driving.





During shift change
Set to line pressure that is necessary for shift change. Therefore, line pressure characteristic is set according to input torque and shift types.





At low fluid temperature
When the A/T fluid temperature drops below the prescribed temperature, in order to speed up the action of each friction element, the line pressure is set higher than the normal line pressure characteristic.