Patent ID: 8550210

Claim:
A muffler comprising: an inner pipe having one end connected to an upstream side of an exhaust pipe of an engine exhaust system, and another end connected to a downstream side of the exhaust pipe; an outer pipe covering at least part of the inner pipe, a hole being formed in a pipe wall of the inner pipe, the outer pipe defining part of an outer shell of the muffler; a resonance chamber formed in a space between the inner pipe and the outer pipe and extending to an inner surface of the outer pipe; and a connection passage formed on an outer peripheral surface of the inner pipe along an axial direction of the inner pipe, the connection passage having a base end side connected to the hole and a tip end side connected to the resonance chamber, wherein an inside of the inner pipe and the resonance chamber communicate with each other through the hole and the connection passage, wherein the tip end side of the connection passage is in fluid communication with the resonance chamber, and wherein the connection passage comprises a plurality of sections connected in series to form the connection passage as a single continuous passage extending from said base end side thereof to said tip end side thereof, the plurality of sections having different distances from the outer peripheral surface of the inner pipe in a radial direction thereof and being mutually overlapped and extending in the axial direction on the outer peripheral surface of the inner pipe.