| 摘要 |
<p>PROBLEM TO BE SOLVED: To suppress generation of vibration of a diaphragm by closing an air bypass valve at the time of a condition in which the diaphragm is vibrated even within a prescribed time after opening the valve. SOLUTION: In the case where a throttle valve 83 is rapidly closed, pressure in second and third leading-in passages 42, 43 are a prescribed value or more, and a change rate per unit time exceeds a prescribed value; it is judged that surge noise is generated from a turbocharger 2. an ABV control valve VSV is driven so as to communicate a control port 56 of an air bypass valve 5 and a surge tank 44 with each other, and the air bypass valve 5 becomes an opening condition. The opening condition is held for a prescribed time. However when it is recognized during that period that a change rate per unit time in the second and third leading-in passages is a prescribed value and less, a condition in which a diaphragm 51 is vibrated is judged. The ABV control valve VSV is driven so as to communicate the control port 56 of the air bypass valve 5 and the third leading-in passage 43 with each other, and the air bypass valve 5 is set to a close condition.</p> |
