| 摘要 |
PROBLEM TO BE SOLVED: To provide an engine exhaust device which can suit with a real vehicle structure, improve volume efficiency, and increase torque.SOLUTION: An engine exhaust device is equipped with: a first exhaust passage 11 which communicates with an exhaust port of an engine; a first muffler 21; a second exhaust passage 12; a second muffler 21; and a third exhaust passage 13. The exhaust path length of a first exhaust path L, a second exhaust path M, and a third exhaust path N is length with which negative pressure waves generated by reflecting exhaust pressure waves discharged from the engine operating at first engine speed, second engine speed, and third engine speed, on a first boundary A, a second boundary B, and a third boundary C reach the exhaust port during a valve overlap period. A capacity of the second muffler 22 is larger than a capacity of the first muffler 21. A cross-sectional area of the second exhaust passage 12 is smaller than a cross-sectional area of the first exhaust passage 11, and a cross-sectional area of the third exhaust passage 13 is larger than a cross-sectional area of the first exhaust passage 11 and a cross-sectional area of the second exhaust passage 12.SELECTED DRAWING: Figure 1 |
