| 摘要 |
PROBLEM TO BE SOLVED: To restrain exhaust interference sound so as to effectively reduce exhaust sound by providing inrush pipe parts projecting into a collecting chamber on the individual exhaust pipes connected to the exhaust ports of No.2 and No.4 cylinders in the ignition order, and forming a plurality of through holes on the side walls of the respective inrush pipe parts. SOLUTION: Thus exhaust manifold 14 of a four-cylinder engine E is constituted so that inner pipes 17 are covered with an outer pipe 18 interposing gaps between both, and the inner pipes 17 are formed so that individual exhaust pipes 201 -204 are connected to the respective exhaust ports 121 -124 of a cylinder head 11 at one-side ends and connected to a collecting pipe 21 forming a collecting chamber at the other end. In this case, the individual exhaust pipes 203 , 202 connected to the exhaust ports 123 , 122 of the No.2 and No.4 cylinders in the ignition order in the individual exhaust pipes 201 -204 , are respectively integratedly connected to inrush pipe parts 32, 33 projecting in the collecting chamber at the other ends. A plurality of through holes are formed on the side walls of the respective inrush pipe parts 32 33, so as to reduce exhaust interference sound.
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