| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an intake and exhaust device of a multi-cylinder engine capable of increasing engine output in a full rotation region with a simple structure. <P>SOLUTION: A downstream end of an exhaust passage 54 has a shape having a flow passage area at a downstream side smaller than that of the upstream side so that another adjacent exhaust passage 54 has a negative pressure by ejector effect. In a low-speed region, an overlap period of one cylinder 12 and a valve opening start timing of an exhaust valve 20 of the other cylinder 12 having successive exhaust order are overlapped with each other. A length and a cross-sectional area of the intake passage 3 is set to a size so that a first-order synchronization rotation speed Nin_1a obtaining intake inertia supercharging effect is higher than a reference rotation speed N1 and so that a second-order synchronization rotation speed Nin_1c obtaining intake inertia supercharging effect and a non-synchronization rotation speed Nin_1b which is an engine rotation speed between the synchronization rotation speeds and at which the amount of decrease in volume efficiency due to the effect of a negative pressure wave of intake pulsation between the synchronization rotation speeds is the largest are lower than the reference rotation speed N1. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
