Hydraulic control system of automatic transmission for vehicle

A hydraulic control system of an automatic transmission for a vehicle, comprising:

• an oil pump for generating a hydraulic pressure;
• a pressure regulating valve for receiving the hydraulic pressure from the oil pump and for properly regulating the hydraulic pressure at drive "D" or reverse "R" ranges;
• a torque converter, which includes a damper clutch valve, for transmitting driving power from an engine to an input shaft of the transmission;
• a converter clutch regulator valve for supplying the hydraulic pressure to the damper clutch to actuate the damper clutch;
• a solenoid supply valve for reducing and supplying the hydraulic pressure, which is regulated at the pressure regulating valve, to first, second, third, fourth, fifth, sixth and seventh solenoid valves;
• a first friction element which is actuated at all speed ratios and second, third, fourth, fifth, sixth, seventh and eight friction elements more than one of which is actuated at each speed ratio;
• a torque control regulator valve for converting the hydraulic pressure into a torque control hydraulic pressure for actuating the friction elements for each speed ratio;
• a control switch valve for receiving the torque control hydraulic pressure from the torque control regulator valve and for changing a flowing direction of the torque control hydraulic pressure;
• first-second, second-third, third-fourth, and fourth-fifth speed shift valves for selectively supplying the torque control hydraulic pressure supplied from the control switch valve or a drive hydraulic pressure regulated by the pressure regulating valve to the friction elements for each speed ratio in accordance with ON/OFF operation of the first, second and third solenoid valves to change the speed ratio;
• second speed clutch, third speed clutch, a fourth speed band, and an overdrive unit valves, all of which are controlled by the torque control hydraulic pressure and the drive hydraulic pressure, for supplying the hydraulic pressure to the friction elements for each speed ratio and the shift valves;
• and
• a manual valve for supplying the hydraulic pressure regulated by the pressure regulating valve to the shift valves or a reverse friction element.