An exhaust muffler is made up of a plurality of layers including an exhaust passage pipe and expansion chambers, and includes a front assembly and a rear assembly sub-assembled separately from the front assembly. The front assembly includes a front exhaust passage pipe, a front muffler body disposed in covering relation to the outside of the front exhaust passage pipe and cooperating with the front exhaust passage pipe in making up double-walled pipes, and an exhaust valve disposed in the front exhaust passage pipe. The rear assembly includes a rear exhaust passage pipe and a rear muffler body disposed in covering relation to the outside of the rear exhaust passage pipe and cooperating with the rear exhaust passage pipe in making up double-walled pipes. There is thus provided an exhaust device for an internal combustion engine in which the accuracy of a position where the exhaust valve is installed is high.

An exhaust muffler includes a first muffler section connected to an exhaust pipe and a second muffler section connected to the first muffler section. Exhaust gases delivered from the exhaust pipe are discharged from the first muffler section and the second muffler section out of the exhaust muffler. The first muffler section includes a tubular member made up of an inner pipe to which the exhaust pipe is connected and an outer pipe covering the inner pipe, and a connector connecting the tubular member and the second muffler section to each other. The first muffler section has a first expansion chamber defined therein between the inner pipe and the outer pipe. The inner pipe houses therein a valve for changing an amount of exhaust gases passing through the inner pipe. The first muffler section includes a curved portion that is curved vertically as viewed in side elevation of the vehicle. The exhaust muffler has a second expansion chamber defined in the second muffler section rearward and upward of the first muffler section, the second expansion chamber having a cross-sectional area larger than a cross-sectional area of the first expansion chamber. There is thus provided an exhaust device for an internal combustion engine, which includes a muffler compact in a longitudinal direction thereof.

A combined exhaust gas noise silencer consisting of a system of hollow elements with a mutual housing comprising a front face of the silencer connected to the supply pipe of exhaust gases, and a rear face of the silencer with an outlet from the rear face of the silencer, where the originalinlet exhaust gas (?.sub.p) carrying a noise wave is divided into at least two flowsan exhaust gas flow (?.sub.z) carrying a shifted noise wave with delayed wave length, and an exhaust gas flow (?.sub.n) carrying a non-shifted noise wave, which are subsequently combined into a common exhaust gas flow (?.sub.s).

An exhaust purification device for purifying exhaust gas flowing in an exhaust gas flow passage of an engine includes: a cylindrical casing; a pipe that is disposed on a downstream side of the casing and inserted in the casing so as to extend in a direction substantially orthogonal to an axial direction of the casing, the pipe being provided with a through-hole communicating with the casing; and an injector configured to inject a reducing agent from an upstream end of the pipe into the pipe, in which a contracting flow passage portion narrowing in an axial direction of the pipe from an upstream side toward the downstream side is formed in the exhaust gas flow passage in the casing.

An exhaust chamber is disposed in an exhaust passage through which exhaust gas from an engine passes. The exhaust chamber includes: an inner case having a chamber expansion region therein; and an outer case configured to cover a portion of the inner case. The inner case has a first inner case half and a second inner case half which are obtained by division into two parts, and is formed by the first inner case half and the second inner case half being joined to each other at an inner joining portion. The outer case has a first outer case piece and a second outer case piece which are spaced from each other. The first outer case piece and the second outer case piece are each joined to a portion, on an outer surface of the inner case, which portion is different from the inner joining portion.

An apparatus and method for attenuating sound from an engine exhaust. The relative lengths of the expansion chambers and other components within the apparatus provide a quadruple tuning effect which attenuates sound over a wide frequency range. Attenuation at higher frequencies is also increased and extended by the use of acoustically lined internal baffle tubes inside the apparatus housing.

An exhaust muffler in which the anti-scattering property of a sound deadening element is high and for which shaping is not required and a sound deadening element for use with the exhaust muffler. An exhaust muffler includes an expansion chamber into which exhaust gas of an engine is introduced, and a sound deadening element in which the expansion chamber is inserted. The sound deadening element is configured from a knitted article formed by knitting continuous fibers of glass fiber. The exhaust muffler further includes an inner pipe inserted in a spaced relationship from an inner circumferential wall of the expansion chamber in the expansion chamber and configured to introduce the exhaust gas therethrough. The sound deadening element is disposed between an outer circumferential wall of the inner pipe and the inner circumferential wall of the expansion chamber.

An apparatus and method for attenuating sound from an engine exhaust. The relative lengths of the expansion chambers and other components within the apparatus provide a quadruple tuning effect which attenuates sound over a wide frequency range. Attenuation at higher frequencies is also increased and extended by the use of acoustically lined internal baffle tubes inside the apparatus housing.

A silencer includes conduit with a downstream end portion configured from a tubular member which includes a conduit discharge port extending through a silencer main body and discharges exhaust gas to the outside therethrough. The tubular member includes a resonance communication hole communicating with a resonance chamber and an upstream side communication hole and a downstream side communication hole communicating with a second chamber. A barrier wall serving as a throttle portion for throttling an exhaust path at an intermediate location of the tubular member is provided in the inside of the tubular member and between the upstream side communication hole and the downstream side communication hole.

An exhaust muffler in which the anti-scattering property of a sound deadening element is high and for which shaping is not required and a sound deadening element for use with the exhaust muffler. An exhaust muffler includes an expansion chamber into which exhaust gas of an engine is introduced, and a sound deadening element in which the expansion chamber is inserted. The sound deadening element is configured from a knitted article formed by knitting continuous fibers of glass fiber. The exhaust muffler further includes an inner pipe inserted in a spaced relationship from an inner circumferential wall of the expansion chamber in the expansion chamber and configured to introduce the exhaust gas therethrough. The sound deadening element is disposed between an outer circumferential wall of the inner pipe and the inner circumferential wall of the expansion chamber.