A muffler for an exhaust system of an internal combustion engine includes a muffler housing having a peripheral wall elongated along a longitudinal housing axis. The muffler has an end wall on each axial end region of the peripheral wall and a muffler insert, surrounded by the peripheral wall and supported on the peripheral wall. A retaining wall extends substantially in the direction of the longitudinal housing axis and a first exhaust-gas routing pipe is positioned with a first end region engaging in an opening in the peripheral wall and is secured to the peripheral wall and retained with a second end region on the retaining wall. The first exhaust-gas routing pipe is retained in its second end region on the retaining wall by force closure or interlocking.

A muffler for an exhaust system of an internal combustion engine includes a muffler housing having a peripheral wall elongated along a longitudinal axis of the muffler housing. The peripheral wall has first and second end walls. A muffler insert is surrounded by the peripheral wall and is supported thereon. The muffler insert has a retaining wall extending in a direction of the longitudinal axis. The peripheral wall has a peripheral wall opening and a first exhaust-gas routing pipe has a first end region and is positioned with the first end region thereof engaging in the peripheral wall opening. The first exhaust-gas routing pipe has a second end region and is secured by the second end region thereof to the retaining wall. The first exhaust-gas routing pipe is of multi-part configuration and has a first pipe part and a second pipe part.

Provided is a muffler that can reduce sound pressure of a standing wave in an outlet pipe and, at the same time, can inhibit generation of flow noise. In one aspect of the present disclosure, the muffler includes a housing, an outlet pipe, a cover that covers the outlet pipe. The outlet pipe includes an outlet end and at least one communication hole. The outlet end opens into the housing. The at least one communication hole is formed in an outer circumferential surface of the outlet pipe. The cover includes a wall portion and an opening. The wall portion is disposed to overlap with the at least one communication hole in a radial direction of the outlet pipe. The opening communicates the at least one communication hole and an internal space of the housing with each other.

Disclosed herein is a meta-muffler for reducing broadband noise. The meta-muffler includes: a flow pipe through which a fluid flows; an outer barrel disposed outside the flow pipe to be spaced apart from the flow pipe; and multiple metastructures arranged in a flow direction of the fluid and each comprising an opening opened parallel to the flow direction of the fluid, a resonance chamber disposed between the flow pipe and the outer barrel and communicating with the flow pipe through the opening, and a neck adjustment member extending from the outer barrel toward the flow pipe to be spaced apart from the opening in the flow direction of the fluid. The meta-muffler can increase transmission loss of noise flowing through the flow pipe through maximization of energy loss of sound waves entering the resonance chamber of the metastructure and can effectively attenuate noise over a wide band ranging from low frequencies to high frequencies.

Provided acoustic devices include an external housing defining an expansion chamber and a wall extending through and partitioning the expansion chamber into a central chamber and a peripheral chamber adjacent the central chamber, wherein an inlet and outlet communicate with the central chamber, and wherein the wall includes a plurality of apertures formed therethrough to allow air movement to and from the central and expansion chambers, the plurality of apertures sized to provide an average flow resistance ranging from 100 MKS Rayls to 5000 MKS Rayls. The acoustic devices advantageously show significant sound attenuation while streamlining air flow to reduce pressure drop across the expansion chamber.

Waveguide or flow guide surfaces can improve the efficiency of fluid flow through tubes or over surfaces. When incorporated in a tube, the waveguides improve flow and function as sound absorbers making them useful in engine mufflers, firearm silencer/suppressors and jet engine exhaust attenuators. On surfaces, the waveguides can reduce fluid drag and find use on projectiles (e.g., bullets), airfoils for aircraft, and land borne vehicles. The waveguide array in either a tubular chamber or on a surface comprises a plurality of successive wave-like undulations inclined generally in the direction of flow and when employed in tubes extending inwardly to permit an unobstructed path for the fluid gas from entry to exit. The waves define annular wave cavities between their successive inwardly extending edges and the wall of the chamber with each cavity having a cavity mouth open to the unobstructed path. The waveguides are sized and spaced so that gas vortices are created within the cavities when gas flow occurs which vortices create a fluid boundary layer that assists the gas flow.

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.

A muffler for receiving exhaust gas from a combustion engine may include a shell, an inlet pipe, at least one outlet pipe, one or more baffles, and an internal communication pipe. The inlet pipe may extend through the shell. The outlet pipe may be in fluid communication with the inlet pipe and may be at least partially disposed within the shell. The baffles are disposed within the shell and cooperate with the shell to define a plurality of chambers. The internal communication pipe may be disposed entirely within the shell and may be in fluid communication with the inlet pipe. The internal communication pipe may include an inlet opening and first and outlet openings. The first outlet opening is open to and in direct fluid communication with one of the chambers. The second outlet opening is open to and in direct fluid communication with another one of the chambers.

One aspect of the present disclosure provides an exhaust unit including a housing, a wall member, a catalyst, and a muffler chamber. The housing includes a feed inlet and a discharge outlet. The housing is configured such that an exhaust gas of an internal combustion engine is introduced from the feed inlet, and the exhaust gas is discharged from the discharge outlet. The wall member is disposed in the housing, and forms a cylindrical flow path that guides a flow of the exhaust gas introduced from the feed inlet to curve along an outer circumference of an interior of the housing. The catalyst is disposed in the flow path. The muffler chamber communicates with the flow path in a downstream side of the catalyst in the flow path. The wall member serves as a part of a wall that defines an inside and an outside of the muffler chamber.

An exhaust system noise reduction device of a vehicle enables an exhaust system to contribute to an increase in engine output while reducing engine exhaust noise. The exhaust system noise reduction device includes a muffler housing formed to airtightly surround a rear end section of an exhaust pipe; a branch pipe branched from a front end section of the exhaust pipe while having a rear end section of the branch pipe extend through the muffler housing; a barrier wall disposed at a peripheral surface of the rear end section of the exhaust pipe to divide an inner space of the muffler housing into a first chamber and a second chamber; and a punched portion formed at the rear end section of the branch pipe and disposed in the first chamber. A resonance chamber structure for reducing exhaust noise is formed in the first chamber, thereby reducing exhaust noise.