A LINE PRESSURE VARIABLE CONTROL METHOD AND A SYSTEM THEREOF FOR AN AUTOMATIC TRANSMISSION

摘要

The method involves calculating a minimum line pressure based on an automatic transmission operating condition if current shift range is one of forward driving shift ranges. A solenoid duty ratio is calculated corresponding to the pressure. A solenoid correction duty ratio is calculated based on an amount of clutch slip if there is slip. The duty ratio is modified with correction duty ratio and a solenoid valve is controlled. An independent claim is also included for a line pressure variable control system for an automatic transmission.