Patent ID: 7617676

Claim:
A hydraulic control apparatus for a vehicular fluid-actuated power transmitting device provided with a lock-up clutch and an oil cooler, said lock-up clutch being operable between an engaged state and a released state according to a difference between pressures of a working fluid in an engaging fluid chamber and a releasing fluid chamber, said oil cooler being connected to a fluid passage communicating with said engaging and releasing fluid chambers, and operable to cool the working fluid, said hydraulic control apparatus by comprising: an oil cooler by-pass valve operable to permit the working fluid to by-pass said oil cooler; and a low-temperature by-pass device operable to open said oil cooler by-pass valve, that permits the working fluid to by-pass the oil cooler, when a temperature of the working fluid is lower than a predetermined lower limit, and wherein the low temperature by-pass device includes a control valve selectively operable to control an engaging pressure of the lock-up clutch and to open said oil cooler by-pass valve.