Patent ID: 7225071

Claim:
A transmission control system comprising: an automatic transmission connected to an engine, the automatic transmission comprising a torque converter and a power transmission clutch that is engaged to transmit an output rotation from the torque converter when supplied with hydraulic pressure upon start of a vehicle; a hydraulic pressure circuit that supplies hydraulic pressure to the power transmission clutch; and a controller connected to the hydraulic circuit to control the hydraulic circuit, wherein the controller: has a plurality of memory regions partitioned according to an operation state of the automatic transmission; reduces the hydraulic pressure supplied from the hydraulic pressure circuit to the power transmission clutch when the vehicle is stopped with the engine in an idling state; increases the hydraulic pressure supplied to the power transmission clutch to an initial pressure once a turbine rotation speed has increased to a predetermined rotation speed; controls the hydraulic pressure supplied to the power transmission clutch to approach a target hydraulic pressure once the hydraulic pressure supplied to the power transmission clutch has increased to the initial pressure, the target hydraulic pressure being a hydraulic pressure at which a slip amount, which is equal to a difference between the turbine rotation speed and an engine rotation speed, becomes a target slip amount; sets a correction value of the initial pressure for causing the slip amount to approach a target slip amount once the hydraulic pressure supplied to the power transmission clutch has converged; stores the set correction value in a memory region corresponding to an operation state of the automatic transmission at a point when the correction value is set, and corrects the initial hydraulic pressure according to a correction amount stored in a memory region corresponding to the operation state of the automatic transmission at a point when the turbine rotation speed increases to the predetermined rotation speed.