Patent ID: 8136627

Claim:
An exhaust silencer device for an internal combustion engine, comprising: an exhaust pipe that forms an exhaust passage extending from the internal combustion engine, and forms an exhaust opening; and a muffler attached to the exhaust pipe so as to silence an exhaust gas from the internal combustion engine, wherein the exhaust passage comprises a first exhaust passage extending from an outlet of an additional muffler that is attached to the exhaust pipe at a position upstream of the muffler to the muffler and a second exhaust passage extending from the muffler to the exhaust opening; the first and second exhaust passages are of equal piping lengths, and a hole is formed on at least one of the exhaust passages whereby the resonance frequencies of the first exhaust passage and of the second exhaust passages are different from each other, wherein the exhaust opening opens to atmosphere.