| 摘要 |
PROBLEM TO BE SOLVED: To provide an exhaust device of a multi-cylinder engine, capable of increasing an intake amount with simple structure to increase engine output.SOLUTION: The exhaust device of a multi-cylinder engine includes: independent exhaust passages 53 respectively connected to exhaust ports 18; flow passage area variable valves 58 which can change flow passage areas of independent exhaust passages 53; and a flow passage area variable valve drive means 58b. In a low-speed region R1, exhaust valves 20 are opened during an overlap period of intake valves 19 and the exhaust valves 20, and flow passage areas of high-speed-side passages 53 are restricted. In the overlap period, a valve lift time area S_VL2 of a valve smaller in valve lift out of the intake valve 19 and the exhaust valve 20 in a period from an exhaust top dead center to valve closing timing EVC of the exhaust valve 20, is set to be larger than a valve lift time area S_VL1 of a valve smaller in valve lift out of the intake valve 19 and the exhaust valve 20 from valve opening timing IVO of the intake valve 19 to the exhaust top dead center in the overlap period. |
