| 摘要 |
PURPOSE:To secure an intake air amount matching acceleration by opening a switching valve on rapid acceleration during a clutch-off condition with the switching valve closed, in order to reduce torque shock generated during a transient running state toward supercharging operation range. CONSTITUTION:In the operational range where no supercharge is applied with an electromagnetic clutch 36 being in an OFF-condition, pressures in the lower and the upper chambers 34a, b of a switching valve 34 become identical to each other, so that the switching valve 34 is closed. Intake air passes through, not a bypass passage 32, but a supercharger 26 in order to produce prerotation, so that, when either one of engine speed and throttle opening is increased, the electromagnetic clutch 36 is turned on so as to reduce torque shock for driving the supercharger 26. When the electromagnetic clutch 36 is in the OFF- condition on rapid acceleration, negative pressure on the lower stream side of the supercharger 26 becomes smaller than that of a throttle valve 24, so that pressure in the upper chamber 34b of the switching valve 34 becomes lower than that in the lower chamber 34a, and that a valve body 34c opens the bypass passage 32.
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