Control system for automatic transmission

摘要

A control system for an automatic transmission, comprising: a fluid coupler for transmitting the rotation of an engine to a transmission; a clutch adapted to be applied, when a forward running range is selected, and released when a neutral range is selected; range selecting means for selecting a range; range detecting means for detecting the selected range; a hydraulic circuit; and a control unit. The hydraulic circuit includes: a hydraulic servo adapted to be fed with an oil pressure for applying the clutch; a manual valve adapted by operating the range selecting means to take at least a forward range position for generating a forward range oil pressure and a neutral range position; a regulator valve for regulating the forward range oil pressure to generate a regulated oil pressure; a solenoid valve adapted to be turned ON/OFF by the control unit for generating a signal oil pressure; and a change-over valve adapted to be switched in response to the signal oil pressure for taking a first position to feed the forward range oil pressure to the hydraulic servo and a second position to feed the regulated oil pressure to the hydraulic servo. The control unit includes delay means for outputting, if a switching from the forward running range to the neutral range is detected by the range detecting means, a signal to the solenoid valve so that the change-over valve may be placed in the second position till a set time period elapses, and in a first position when the set time period elapses.