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.

An exhaust device (108) for a vehicle is provided. The exhaust device (108) includes an outer shell (202), an inlet (206) to receive exhaust gases, an outlet (208), an inner shell (204) received within the outer shell (202), a pair of partition walls (216) and a Helmholtz neck (220). The inner shell (204) defines an inner volume (210). A plurality of first circumferential openings (212) extending through the inner shell (204) fluidly communicates the inlet (206) with the inner volume (210). A plurality of second circumferential openings (214) extending through the inner shell (204) fluidly communicates the outlet (208) with the inner volume (210). The pair of partition walls (216) is disposed between the inner shell (204) and the outer shell (202). The pair of partition walls (216), the inner shell (204) and the outer shell (202) define a Helmholtz chamber (218) therebetween. The partition walls (216) seal the Helmholtz chamber (218) from the inlet (206) and the outlet (208). The Helmholtz neck (220) is disposed on the inner shell (204) or one of the pair of partition walls (216).

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.

A silencer for an exhaust gas system of an internal combustion engine includes a silencer housing which surrounds a silencer interior and which has at least two housing portions which are adjacent to each other in an abutment region. The two housing portions are connected to each other. The silencer housing has at least one housing opening formed therein and an outlet pipe extends through the silencer housing in the region of the housing opening. The housing opening is completely formed in one of the two housing portions.

A sound attenuator has an inner pipe (12) with expansion sections (121) of enlarged diameter corresponding to the constriction sections (141) of an outer pipe (14). The expansion sections (121) in pairs axially delimit an intermediate inner pipe section (122) containing a wall opening (18) and having a reduced diameter relative to the expansion sections (121). The inner surface of the outer pipe (14) in each of its constriction sections (141) is connected to the outer surface of the inner pipe (12) in its respective corresponding expansion section (121). A method of manufacturing such a sound attenuator (10) also is provided and uses internal high-pressure forming.

A space-saving broadband resonator configured to install within and utilize inner space of other components and includes a resonator insert having a tubular pipe elongated along a central axis, the tubular pipe having a circumferential outer wall having a plurality of perforation holes spaced apart and extending radially through the circumferential outer wall. An interior of the tubular pipe forms a gas flow duct. A plurality of annular disk-shaped walls provided on and projecting radially outwardly from the tubular pipe. Adjacent annular disk-shaped walls spaced axially part from each other define resonator chambers therebetween. A bell mouth is formed at the second axial end of the tubular pipe, the bell mouth flared radially outwardly.

A multi-mode muffler for an exhaust system of an internal combustion engine provides a rotary plate that modulates exhaust gas flow between a first and second flow path. Each flow path may provide different sound dampening characteristics, thereby providing different sound profiles with the same muffler. In a disclosed embodiment, the rotary plate is driven by a shaft coupled to an external actuator. Also, a third possible position of the rotary plate may allow flow through both the first and second flow paths, thereby providing a third possible noise profile. One of the sound profiles may be louder than the other thereby allowing the muffler to switch between “loud” and “quiet” modes of operation.

A vehicle exhaust system includes a tubular component having an inner surface and an outer surface such that the inner surface defines a primary exhaust gas flow path and wherein the tubular component extends along a central axis from an inlet end to an outlet end. The tubular component comprises at least one ridge along the central axis. The at least one ridge extends at least partly along a circumference of the tubular component. Each ridge includes a first portion angularly devoid of apertures and extending inwardly from the tubular component and a second portion disposed downstream of the first portion. The second portion is angularly devoid of apertures and extends inwardly from the tubular component. The tubular component also includes a plurality of spaced apertures positioned along a portion of the circumference of the tubular component and downstream of the second portion.

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.

A compact slip-in spark arrester having an interior shell (125) with a circular cross-section changing in diameter along its axial length which is axially aligned between an inlet cap member (115) and an outlet cap member (145). The tubular center section (130) of the interior shell (125) containing a centrifugal whirling means to remove any particulate matter from the exhaust flow by means of centrifugal force or deflection and trapping the particulate matter in an outer chamber (155) between the interior shell (125) and existing silencer shell (100).