Patent ID: 7713165

Claim:
A hydraulic control system for a continuously variable transmission for a hybrid electric vehicle, in which speed changes are made based on input torques and engine rotational speeds, wherein: pressure of a primary pulley is controlled by a ratio control valve based on engine rotational speeds when a transmission control unit fails; the ratio control valve is controlled by a first ratio control pressure 1 and a second ratio control pressure 2 ; the ratio control valve is controlled by being connected with a first start clutch control pressure 1 as the first start clutch control pressure 1 is supplied to a flow path of the second ratio control pressure 2 through a limp home valve when the transmission control unit fails; if the engine rotational speed is increased, the pressure of the ratio control valve rises and the continuously variable transmission moves upward, whereas, if the engine rotational speed is decreased, the pressure of the ratio control valve falls and the continuously variable transmission moves downward; and wherein the limp home valve comprises: a valve housing defining parts communicating with plural flow paths comprising a flow path receiving pressure of a secondary control solenoid valve from an end, a flow path supplying the ratio control pressure 1 , a flow path supplying a pressure to a manual valve, a flow path supplying the ratio control pressure 2 , a flow path receiving the start clutch control pressure 1 , a flow path receiving the pressure of a start clutch control solenoid valve, a flow path receiving a pressure of a start clutch control valve, a flow path receiving a pressure of a secondary regulatory valve and supplying the same to the start clutch control valve, and a flow path receiving the pressure from a secondary regulator; and a plurality of operation plungers established in series inside the valve housing controlling communication between said flow paths and a spring supporting the operation plunger positioned an end of said housing.