HYDRAULIC CONTROL SYSTEM OF 8-SHIFT AUTOMATIC TRANSMISSION FOR VEHICLES

摘要

A hydraulic control system of 8-shift automatic transmission for vehicles is provided to reduce the fuel consumption and minimize the shift impact by precisely controlling the automatic transmission with simple control method. A hydraulic control system of 8-shift automatic transmission for vehicles comprises the first and second clutch control section(E), the third clutch control section(G), the fourth clutch, the first brake control unit(H), and the second brake control unit(I). The first and second clutch control sections selectively receive the control pressure of the first pressure control valve(18) controlled by the first ratio control solenoid valve(VFS1). The third clutch control section receives the control pressure of the second pressure control valve(24) in which the third clutch is controlled by the second ratio control solenoid valve(VFS2) as the trigger pressure. The fourth clutch and the first brake control unit share the control pressure of the third pressure control valve(32) in which the fourth clutch and the first brake are controlled by the third ratio control solenoid valve(VFS3). The fourth clutch and the first brake control unit supply the rear pressure to the first brake.