Patent ID: 6080084
Filing Date: 2000-06-27
Classification: F16H,Y10T

Abstract:
An apparatus for controlling an automatic transmission operatively connected to an engine of a motor vehicle, wherein a shifting action of the automatic transmission is achieved by releasing one of two hydraulically operated frictional coupling devices while at the same time engaging the other of said two frictional coupling devices, said apparatus comprising:rapid pressure reduction means for rapidly reducing a pressure of said one of said two hydraulically operated frictional coupling devices to a predetermined pressure level, upon determination that said shifting action of the automatic transmission should be achieved;releasing pressure hold means for holding the pressure of said one of said two frictional coupling devices at said predetermined pressure level for a predetermined hold time;continuous pressure reduction means for continuously reducing the pressure of said one frictional coupling device at a predetermined reduction rate upon expiration of said predetermined hold time;engine overshoot detecting means for detecting an overshoot of the engine due to an insufficient amount of simultaneous partial engagements of said two frictional coupling devices during said shifting action of the automatic transmission; andlearning compensation means for updating, by learning compensation, a control parameter which influences a pattern of change of the pressure of said one frictional coupling device during said shifting action, such that an amount of said overshoot of the engine is held within a predetermined range,and wherein said control parameter is selected from among: said predetermined pressure hold time for which the pressure of said one frictional coupling device is held at said predetermined level by said releasing pressure hold means; said predetermined reduction rate at which the pressure of said one frictional coupling device is continuously reduced by said continuous pressure reduction means; and a time duration during which fast filling of said other frictional coupling device with a working fluid is effected.