摘要 |
A hydraulic control system of a vehicle power train having a belt-type continuously variable transmission, and a hydraulic lock-up clutch, includes: a line pressure control valve; first and second control valves; first, second and third electromagnetic valves; and a fail-safe valve. The fail-safe valve is switched to a fail position in which a line pressure is supplied to one of a drive pulley and a driven pulley when a rapid deceleration state is likely to occur in the belt-type continuously variable transmission, the fail-safe valve is switched to a normal position in which a hydraulic pressure output from the first control valve is supplied to the one of the drive pulley and the driven pulley during times other than the above, and the fail-safe valve is switched by a combination of a hydraulic pressure controlled by the second electromagnetic valve and a hydraulic pressure controlled by the third electromagnetic valve.
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