| 摘要 |
<P>PROBLEM TO BE SOLVED: To combine using an ejector effect in a low-speed area and reducing exhaust resistance in a high-speed area. <P>SOLUTION: The exhaust device includes: independent exhaust passages 16A-16D connected to cylinders 2A-2D; a collection part 17 where downstream ends of the respective independent exhaust passages 16A-16D are collected; a merging part 18 connected to the downstream side of the collection part 17; communication passages 25A, 25B communicating the respective independent exhaust passages of a plurality of cylinders, exhaust order of which is not in series, (between the exhaust passages 16A and 16D, and between the exhaust passages 16B and 16C); and variable valves 26 respectively provided for the communication passages 25A, 25B. Valve timing of each cylinder is set so that an overlapping period (O/L) of one cylinder in cylinders exhaust order of which is in series overlaps a valve-opening period of an exhaust valve 6 of the other cylinder. Opening of the variable valve 26 is kept at 100% (full throttle) when engine rotation speed is equal to or higher than a predetermined value Nex, and is reduced to lower than 100% when the engine rotation speed is lower than the predetermined value Nex. <P>COPYRIGHT: (C)2013,JPO&INPIT |
