| 摘要 |
PURPOSE:To enable an internal combustion engine proper itself to possess a silencing function and to simplify and miniaturize a silencer, by a method wherein an expansion chamber, which is formed with an enlarged bore portion, is located on the way of an exhaust gas path in a cylinder block. CONSTITUTION:In a 2-cycle engine, an expansion chamber 14, which is formed with an enlarged bore portion 5a on the way of an exhaust gas path, i.e., on the side where the exhaust gas path connects to an exhaust pipe 13. The exhaust pipe 13 is connected to the expansion chamber 13 through the medium of a coupling flange 15. When the engine runs, exhaust gas, which is released to an exhaust gas path 5 with an exhaust port 4 opened resulting from coming down of a piston 8, comes into the expansion chamber 14 first through a path 5c having a small caliber. After it is expanded therein, it comes into the exhaust pipe 13 for contraction. This causes damping, to some degree, of an acoustic energy possessed by the exhaust gas, and it is then further silenced by a silencer. |
