An exhaust muffler has an outer cylinder into which an exhaust gas from an engine is introduced and a muffling member made of a foamed ceramic material. The outer cylinder has an inner cylinder through which the exhaust gas passes, a part of the muffling member is supported by an outer wall of the inner cylinder via a holding member. The inner cylinder includes, in an area where the inner cylinder overlaps with the muffling member with respect to axial direction of the inner cylinder, a porous wall portion formed with communication holes communicating an inside and an outside of the inner cylinder. The holding member is arranged at a position where it does not overlap with a part of the porous wall portion, so that muffling effect is enhanced, and the muffling member having a low resistance to impact forces can be supported stably by the inner cylinder.

A muffler for receiving exhaust gas from a combustion engine comprises a shell, first and second inlet pipes each having outlets providing exhaust gas to a mixing chamber within the shell, a first chamber and a second chamber positioned within the shell and a pair of communication pipes each including an inlet receiving exhaust gas from the mixing chamber. Each communication pipe includes an outlet providing exhaust to the second chamber. Each of the communication pipes further includes a Helmholtz opening positioned downstream of the mixing chamber. The Helmholtz openings are open to the first chamber.

An acoustic damper includes a low porosity layer section and a housing. The low porosity layer section is formed in a liner of a gas turbine combustor and has an arrangement of elongated generally S-shaped slots formed therein. The housing has a plurality of feed apertures. The housing is coupled to the low porosity layer section thereby defining a cavity such that air outside the housing is configured to flow through the apertures and through the elongated generally S-shaped slots in the low porosity layer section, thereby transforming acoustic energy into thermal energy and aiding in providing an acoustic dampening effect for the gas turbine combustor during operation thereof.

An air exhausting device includes a muffler internally divided into a plurality of chambers by a separator, an inlet pipe that couples an exhaust pipe of an engine to the muffler, and an outlet pipe that is a path to discharge an exhaust gas inside the muffler to outside air. The muffler is configured of an expansion chamber to which a downstream end of the inlet pipe opens, and a resonator chamber communicated with only the expansion chamber via a plurality of resonator pipes. Any of or both of lengths and thicknesses of the plurality of resonator pipes are different.

An exhaust after-treatment assembly for an engine system is provided. The exhaust after-treatment assembly includes a housing having an inlet port, an outlet port, a catalyst disposed within a cavity defined by the housing, and a muffler assembly disposed within the cavity downstream of the catalyst. The muffler assembly includes one or more baffle plates disposed longitudinally spaced from one another within the housing to define at least a first resonator chamber and a second resonator chamber. Each of the baffle plates defines an openings aligned to one another about a longitudinal axis of the housing. Further, a resonator tube extends through the openings of the baffle plates and includes an inlet, a perforated portion and one or more outlet ports formed in a wall of the resonator tube. The perforated portion and the outlet ports, respectively in fluid communication with the second resonator chamber and the first resonator chamber.

An exhaust gas system of a motor vehicle which has an internal combustion engine with a plurality of cylinder groups, with a first exhaust gas section which is assigned to a first cylinder group of the internal combustion engine, and with a second exhaust gas section which is assigned to a second cylinder group of the internal combustion engine, each exhaust gas section comprising in each case one exhaust gas purification device, and a common silencer interacting with the first exhaust gas section and the second exhaust gas section, namely in such a way that, starting from the exhaust gas purification device of the first exhaust gas section and starting from the exhaust gas purification device of the second exhaust gas section, in each case, a first part exhaust gas section opens into an interior of the common silencer.

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 original—inlet exhaust gas (İ.sub.p) carrying a noise wave is divided into at least two flows—an exhaust gas flow (İ.sub.z) carrying a shifted noise wave with delayed wave length, and an exhaust gas flow (İ.sub.n) carrying a non-shifted noise wave, which are subsequently combined into a common exhaust gas flow (İ.sub.s).

There is provided a muffler structure of a saddle-type vehicle. The muffler structure is disposed at a downstream side of an exhaust pipe extending from an exhaust port of a cylinder head. A pipe is connected to the exhaust pipe and inserted into a muffler main body. The muffler main body includes a cylindrical portion and a reduced diameter portion joined to a downstream side end portion of the cylindrical portion and having a diameter reduced toward the downstream side thereof. The pipe includes a center pipe passing through the cylindrical portion, and a tail pipe disposed in the reduced diameter portion. An expansion chamber is formed by a space in the reduced diameter portion in the vicinity of the tail pipe.

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.

Methods and systems are provided for an exhaust system of a vehicle. In one example, the exhaust system includes an exhaust tail pipe with an asymmetric outlet. The asymmetric outlet of the tail pipe may flare outwards, away from a central axis of the tail pipe, circumferentially surrounded by a housing with a geometry matching a geometry of the asymmetric outlet.