Shift control system for automatic transmissions

摘要

A shift control system for shifting an automatic transmission from a predetermined gear stage to another by draining an oil pressure from predetermined frictional engagement means connected to an engine to release the same frictional engagement means and by feeding the oil pressure to another frictional engagement means to apply the same frictional engagement means while controlling the drain oil pressure of the frictional engagement means to be released and the application oil pressure of the frictional engagement means to be applied, during the shift. The shift control system comprises blowup detecting means for detecting the blown-up state of the engine being shifted in a clutch-to-clutch manner, and hydraulic control means for controlling at least one of the drain oil pressure of the frictional engagement means to be released and the application oil pressure of the frictional engagement means to be applied, on the basis of the blown-up state of the engine detected by the blowup detecting means, such that the amount of blowup of the engine may fall within a predetermined range. Since the rotation changing state of the engine being shifted is reflected upon the hydraulic control of the frictional engagement means participating in the clutch-to-clutch shift, it is possible to reliably prevent any excessive blowup of the engine and the reduction of the output shaft torque due to the tie-up of the frictional engagement means at all times.