| 摘要 |
PURPOSE:To reduce drive resistance of an oil pump during starting operation of an engine by restricting line pressure to a low value regardless of opened degree of an intake throttle valve during said starting operation thereof. CONSTITUTION:An oil pump 10 forces oil to be discharged into a line pressure oil passage 16. An oil discharge passage 18 is connected to an oil suction passage 12 via the line pressure oil passage 16 and is opened and closed by a relief valve 20. If starting of an engine is ongoing, a solenoid valve 66 is turned on. Since a drain oil passage 64 is opened during the starting operation, control pressure of a pump 38 will be kept zero regardless of opened degree of an intake throttle valve so that a line pressure may become a minimum. Drive resistance of the oil pump can be reduced and increase in resistance against starting operation caused by step-on operation on an accelerating pedal be avoided. |
