Patent ID: 7997382
Filing Date: 2011-08-16
Classification: F01N

Abstract:
1. An exhaust device for a straddle type vehicle with an internal combustion engine, the exhaust device comprising: an exhaust pipe having an engine attachment means at one end, wherein the exhaust pipe comprises a Helmholtz resonator, the Helmholtz resonator is filled with a sound absorbing material, and the Helmholtz resonator is formed with an opening in communication with an inside of the exhaust pipe, and wherein the opening is formed in a place where sound pressure in the exhaust pipe is high when the exhaust pipe is connected to the engine and the engine is operating; and a silencer connected to the exhaust pipe; and wherein: the Helmholtz resonator is filled with sufficient sound absorbing material to substantially eliminate a peak level of a resonance frequency that would be generated in the exhaust pipe by the Helmholtz resonator in the absence of the sound absorbing material.