| 摘要 |
A first catalyst 5 disposed in a first exhaust passage 3a, a second catalyst 6 disposed in a second exhaust passage 3b to be located upstream of the first catalyst 5, a variable valve operating mechanism 11 configured to make lifting amounts of a first and second exhaust valves 8, 9 variable between approximate zero and maximum, and a lifting amount control unit for controlling the lifting amounts of the first and second exhaust valves 8, 9 with the variable valve operating mechanism 11 such that an exhaust gas amount passing through the second exhaust passage 3b is larger than that passing through the first exhaust passage 3a are provided. |
