| 摘要 |
PURPOSE:To reduce the exhaust quantity of the hydrocarbons by allowing the second exhaust ports to communicate each other through the communication passage and arranging an opening/closing valve in an exhaust pipe connected with the communication passage. CONSTITUTION:Each branched pipe 10 is installed at the second exhaust port 9, and the branched pipes 10 are allowed to communicate each other through a communication pipe 11. When the opening/closing valve 15 is closed in a low revolution region and in cold time, the exhaust gas supplied from a cylinder in the final period of explosion cycle is sent under pressure into the combustion chamber of the cylinder in the posterior period of exhaust cycle and accelerates oxidation combustion. Therefore, the discharge quantity of the hydrocarbons can be reduced. |
