A muffler for an exhaust system of a vehicle comprises an outer housing in an interior of which a Helmholtz chamber is formed. A feed body has an opening fluidically connected to the Helmholtz chamber. At least two exhaust pipes extend at least in sections within the outer housing, are spaced apart from each other, and form a flow path for an exhaust gas through the outer housing. The exhaust pipes each have at least two exhaust pipe sections which are entirely spaced apart from each other by a gap in one flow direction of the exhaust gas. The feed body surrounds the exhaust pipes over an entire circumference in a region of the gaps and fluidically connects the exhaust pipes to the Helmholtz chamber.

An apparatus includes a housing defining an internal volume and structured to house aftertreatment component for reducing constituents of an exhaust gas. A noise reducing component is disposed within the internal volume and structured to extend around at least a portion of the aftertreatment component.

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.

An exhaust muffler for an exhaust system of an internal combustion engine includes a muffler housing (12) with an outer shell (14) enclosing a muffler interior (22), through which exhaust gas can flow. An inner shell (54) is arranged in the muffler interior (22) and covers the outer shell (14) in at least some areas on an inner side (52) facing the muffler interior (22).

A reduction device includes a housing defining an input chamber configured to receive exhaust from a power source, an output chamber, an exhaust channel configured to direct the exhaust from the input chamber to the output chamber, and a longitudinal axis. The reduction device also includes a treatment unit disposed in the exhaust channel and along the longitudinal axis. The treatment unit is configured to at least partly remove pollutant species from the exhaust. The reduction device also includes an attenuation component disposed in the housing and radially outward of the treatment unit. The attenuation component is fluidly connected to the exhaust channel, and is configured to attenuate a range of frequencies corresponding to operation of the power source. Additionally, the exhaust channel prohibits exhaust entering the input chamber from exiting the housing without passing through the treatment unit.

Aspects of the present disclosure include a casing comprising an air inlet and an air outlet, a fan configured to move air from the air inlet to the air outlet, and a tunable sound attenuating module having an opening at a first end of the tunable sound attenuating module, a cavity, and a back wall at a second end of the tunable sound attenuating module, wherein: the tunable sound attenuating module is oriented such that the back wall is closer to the fan than the opening, and a length of tunable sound attenuating module is substantially one fourth of the acoustic wavelength of a sound generated by the fan.

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.

A sound suppression assembly is provided for absorbing acoustic energy from an air circulation device. The assembly includes an air circulation device, such as an axial fan, and a plurality of sparsely-arranged two-sided Helmholtz unit cells disposed in a periodic array. Each unit cell includes a lossy resonator and a lossless resonator. The lossy resonator includes a first chamber portion bounded by at least one first boundary wall defining a first chamber volume, and a first neck forming an opening in the first chamber portion. The lossless resonator includes a second chamber portion bounded by at least one second boundary wall defining a second chamber volume, and a second neck forming an opening in the second chamber portion. The unit cells can be positioned in a circular pattern with the first neck of the lossy resonators directed to a source of acoustic energy from the air circulation device.

A lightweight and compact muffler device that can be installed in a limited space in an inside of a generator. A top cover and an undercover (end cover) provided on a top and a bottom of a vertically disposed casing are each formed in substantially trapezoidal shape. Thereby, an inner capacity of the casing can be secured to be large, as a result of which, a size of the muffler device can be made compact, and no extra component is required, so that reduction in manufacturing cost and reduction in weight can be achieved. Since the casing is disposed vertically, it is possible to install the casing even when an installation space is small in an inside of a housing of a generator, and it is possible to make the generator compact.

Provided is a tail pipe in which a silencing effect at a discharge port is obtained. One aspect of the present disclosure is a tail pipe including: an inner tube including a discharge port configured such that an exhaust gas is discharged therefrom; an outer tube arranged so as to form a space between the outer tube and the inner tube by surrounding an outer peripheral surface of the inner tube, an upstream end of the outer tube in a flow direction of the exhaust gas being closed; and at least one communication hole allowing communication between an interior of the inner tube and the space.