Hydraulic control for automatic transmission of motor vehicle - corrects operation of pressure control valve to maintain required gear changing time

摘要

The hydraulic control system initiates a timing interval at the beginning of gear changing and ends the timing interval upon completion of the gear change to provide a time count which is used by a storage pressure control device controlling a pressure-regulating valve for providing a counter-pressure during gear changing. The time count is compared with a required range to allow the energising level of the pressure regulating valve to be adjusted when it lies outside this range. Pref. a linear magnetic valve is used. ADVANTAGE - Prevents variation in gear changing over extended time.