| abstract |
After the engine rotational speed Ne has become below a reference rotational speed Neo, which is lower than an idling rotational speed of the engine, and after the pressure PL of oil passages 103a and 103b has begun to decrease, for a predetermined time, the currents supplied to electromagnetic valves 45 and 46 are adjusted to generate, in each electromagnetic valve, a second biasing force electromagnetically in a magnitude that can supplement a decrease in a third biasing force which is generated by the back pressure led through an oil passage 107 or 108, respectively, and which decreases as the pressure of the oil passages 103a and 103b decreases. After the above mentioned predetermined time has elapsed, the currents supplied to the electromagnetic valves 45 and 46 are set almost to zero. |