Hydraulic line pressure control for vehicular automatic transmission - switches to alternative pattern of variation of fluid pressure when engine load rises above set value

摘要

A hydraulic pressure control coil (44), a locking coil (56), two gear-shift coils (64,66) and a coasting coil (82) are energised through an interface (316) from a control computer (313). Signals are applied from sensors of engine and gearbox input and output shaft speeds (301; 309,302), throttle flap position (303), selector lever position (304) and lubricant temp. (308). Switches provide for kickdown (305), standstill (306), full throttle (307) and overdrive (310). The pattern of pressure variationa is changed under heavy loading. ADVANTAGE - Hydraulic pressure follows actual variation of torque with changes in engine load so as to exclude slipping or jerking in kickdown operation.