Patent ID: 7850571

Claim:
An apparatus for controlling a line pressure of an automatic transmission, the apparatus comprising: a driving information detection unit that obtains information; a shift control unit that determines if a power-on downshift is requested based on the information of the driving information detection unit, and controls the line pressure based on if the power-on downshift is requested; an actuator that forms the line pressure according to a control signal of the shift control unit; and a pressure supply control unit that controls a supply of the line pressure to on-coming and off-going frictional elements of the transmission; and wherein the shift control unit performs: outputting a full value of a line pressure control duty so as to form a full line pressure when the power-on downshift request is detected; reducing the line pressure control duty to a predetermined level when a first shifting is started during the outputting of the full value; and increasing the line pressure control duty to the full value when an increase of a turbine speed is detected due to a finishing of the first shifting; wherein time in which the increase of the turbine speed is detected due to the finishing of the first shifting is when N t ≧(C LP )(N o ), where N t is the turbine speed, N o is an output speed of the transmission, and C LP is a dimensionless coefficient depending on a final target shift-speed.