| 摘要 |
A control system for an automatic transmission of a motor vehicle having a mechanical planetary gear train with hydraulically actuatable gear shift elements, and a manual control valve for delivering a first pressurized fluid to a selected gear shift element when said lever is in one of said forward drive positions comprises a main control valve, responsive to the position of the accelerator pedal and the speed of said vehicle, for controlling the supply of the first pressurized fluid from the manual control valve to the selected element. The main control valve comprises a piston having a first piston surface, which is displaceable between a first position for connecting the supply of first pressurized fluid and a second position for interrupting the supply of first pressurized fluid thereby to disconnect the clutch. A spring acts on the piston against an accelerator pedal position-dependent second fluid pressure which acts on the first piston surface. The piston also has a second piston surface opposed to the first piston surface, and a vehicle speed-dependent third fluid pressure is provided for acting on the second piston surface in opposition to the accelerator pedal position-dependent pressure only when the piston is in the second position, that is, the disengage position.
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