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.

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 a vehicle includes: a case sealed at both ends by first and second side panels; first and second baffle plates installed in the case; a first chamber formed between the first side panel and the first baffle plate; a second chamber formed between the first baffle plate and the second baffle plate; a third chamber formed between the second baffle plate and the second side panel; an intake tube passing through the first side panel, and the first and second baffle plates, and including a first hole formed in a first body section located in the first chamber, and a second hole formed in a second body section located in the second chamber; and a pair of exhaust tubes passing through the first and second baffle plates, and the second side panel, and including a vent hole formed in body section located in the second chamber.

A muffler may include a main body, a perforated tube assembly disposed within the main body, inlet and outlet end cap assemblies connected to opposite ends of the main body, and inlet and outlet expansion chambers defined in opposite ends of the main body by the perforated tube assembly, the inlet and outlet end cap assemblies, and portions of the main body. The perforated tube assembly may include a plurality of perforated tubes with tube supports connected to opposite ends of the perforated tubes. Portions of each perforated tube located between the tube supports may be individually wrapped with insulating material and collectively wrapped with an additional layer of insulating material. Unwrapped portions of each perforated tube may extend into the inlet and outlet expansion chambers defined in the main body.

A muffler cutter is fitted to a tailpipe of a vehicular exhaust system, the muffler cutter includes an exhaust pipe, a plurality of through-holes formed in a side wall of the exhaust pipe, a tubular heat shield plate provided around the exhaust pipe coaxially with the exhaust pipe, and a sound-absorbing heat insulator provided between the exhaust pipe and the tubular heat shield plate. The sound-absorbing heat insulator is partially provided between the exhaust pipe and the tubular heat shield plate so as to have a curved shape. A closed space having a curved shape is formed between the exhaust pipe and the tubular heat shield plate in an area in which the sound-absorbing heat insulator is not provided. The distance between the exhaust pipe and the tubular heat shield plate in an area in which the closed space is formed is 1 to 50 mm.

An engine muffler apparatus for reducing noise and pollution from small gas engines such as those on landscaping tools includes an outer housing having a central neck extension with a principal aperture extending through to an outer housing cavity. The neck extension is selectively engageable with an exhaust of a small gas engine. The outer housing cavity has a plurality of vent apertures. An intake extension tube and a medial tube are coupled to the outer housing cavity. The medial tube has a medial cavity. A first filtering medium is coupled within the medial cavity and filters pollutants passing therethrough. A second filtering medium is coupled within the outer housing cavity outside of the medial tube and dampens sound waves passing through the apparatus from the exhaust.

The present disclosure relates to a field of scroll compressors, and more particularly to a muffler device and a compressor with the muffler device. In one embodiment, a muffler device includes a sound hood inside which an expanding cavity is defined, and a microporous plate which is disposed inside the expanding cavity and divides the expanding cavity into a first cavity body and a second cavity body, and a plurality of through holes are provided in the microporous plate such that the air flow entering the expanding cavity exits the expanding cavity after passing through the plurality of through holes of the microporous plate. The muffler device and the compressor with the muffler device provided herein may effectively reduce the noise of the scroll compressor, especially pneumatic noise.

A muffler may include a shell, first and second baffles, an inlet pipe, first and second outlet pipes, and a communication pipe. The first and second baffles cooperate with the shell to define first, second and third chambers. The first inlet pipe may extend through the shell and may provide exhaust gas to at least one of the first and second chambers. Exhaust gas in the first chamber exits the muffler through the first outlet pipe. Exhaust gas in the second chamber exits the muffler through the second outlet pipe. The communication pipe may include first, second and third openings. The first opening is in communication with the first chamber. The second opening is in communication with the second chamber. The third opening is in communication with the third chamber. The first and second chambers may be in communication with the third chamber through the communication pipe.

In one aspect, a system is provided and includes an engine including an exhaust valve, an exhaust manifold downstream of the exhaust valve and a muffler downstream of the exhaust manifold. The system also includes a catalyst positioned downstream of the exhaust valve.

A vehicle exhaust system includes a tubular component having an inner surface and an outer surface. The vehicle exhaust system also includes at least one opening defined by the tubular component. The at least one opening extends through each of the inner surface and the outer surface. The vehicle exhaust system further includes a patch adapted to cover the at least one opening. The patch includes a first portion extending parallel to the central axis. The first portion defines a plurality of pores. The first portion covers the at least one opening. The patch also includes a second portion extending away from the first portion. The first portion has a first thickness and the second portion has a second thickness.