A silencing apparatus is provided with a shell, ventilation pipes communicating with the inside of the shell, insertion holes which are respectively formed in the shell so as to have sizes smaller than surrounding skirt parts and allow the ventilation pipes to be loosely inserted in, and partitions partitioning the inside of the shell. In the silencing apparatus, at least, a sound-absorbing chamber partitioned by the partition and positioned adjacent to the insertion hole is filled with a sound-absorbing fiber material, and a sound-absorbing fiber material filling gap between the insertion hole and the ventilation pipe is closed by an annular closing member. To provide a silencing apparatus allowing a sound-absorbing chamber to be filled with sound-absorbing fiber material without a gap, even in a complicated configuration having the inside of a shell partitioned by a partition.

A muffler for an exhaust system of an internal combustion engine includes a housing, a through pipe that conducts exhaust gas during operation of the muffler and is guided through the housing, and a branch pipe fluidically branching off from the through pipe within the housing. The branch pipe has an upstream end at the through pipe and ends freely and open at an end face with a downstream end within the housing. The branch pipe has a length from the upstream to the downstream end or up to a lateral recess which has a cross-sectional area which is greater than half a pipe cross-section of the branch pipe. The branch pipe has downstream perforations in a section from ⅜ of the length as measured from the upstream end A total area of the downstream perforations is smaller than half the pipe cross-section of the branch pipe, and no perforations or upstream perforations have a total area of at most 10% of the pipe cross-section of the branch pipe being present in a section before ⅜ of the length.

A muffler includes an exhaust pipe, a shell, and a cover. The exhaust pipe includes communication holes and is configured to allow an exhaust gas to flow through an interior of the exhaust pipe. The shell is disposed outside the communication holes to cover the communication holes. The cover has a tubular shape. The cover is disposed between the exhaust pipe and the shell. The cover is disposed at a distance, which is specified in advance, from the exhaust pipe.

A muffler includes an exhaust pipe, a shell, and a cover. The exhaust pipe includes communication holes and is configured to allow an exhaust gas to flow through an interior of the exhaust pipe. The shell is disposed outside the communication holes to cover the communication holes. The cover has a tubular shape. The cover is disposed between the exhaust pipe and the shell. The cover is disposed at a distance, which is specified in advance, from the exhaust pipe.

A rotating electrical machine such as a generator has a rotor disposed within a rotor housing and an air flow path passing from the rotor housing to and through a silencer to an exhaust. The silencer comprises at least one air flow path disposed adjacent at least one sound absorbing column, the column comprising a first portion having a first sound absorbing material therein and a second portion having a microperforated panel (MPP) and a resonator cavity. The second portion comprises a reactive sound absorbing unit which can be specifically tuned to suppress aero-acoustic noise generated by ventilation slots in the rotor, typically peaks at 100 Hz or 120 Hz.

A vehicle exhaust system includes a component housing defining an internal cavity and at least one exhaust gas treatment element positioned within the internal cavity. A resonator volume is connected in parallel with the internal cavity via at least one resonator element and insulating material is located within the resonator volume.

A vehicle exhaust system includes a component housing defining an internal cavity and at least one exhaust gas treatment element positioned within the internal cavity. A resonator volume is connected in parallel with the internal cavity via at least one resonator element and insulating material is located within the resonator volume.

A sound isolation window includes a frame and a plurality of sound blocking bars. The frame has an upper frame portion and a lower frame portion. The frame further has a first sidewall and a second sidewall connected to the upper and lower frame portion. The upper frame portion, the lower frame portion, the first sidewall and the second sidewall form a first opening and an opposite second opening. Each sound blocking bar includes a plane perpendicular to the upper frame portion and the lower frame. The sound blocking bars are arranged along the first direction from the first opening to the second opening and spaced apart from each other. Projections along the first direction of the sound blocking bars over the first opening cover the first opening. The width of each sound blocking bar is less than one-half of the width of the first opening.

An exhaust component for a motor vehicle includes a wall, an internal volume, an inlet, and an outlet. The wall includes a core layer having a surface and a first layer disposed on a portion of the surface. The portion is less than 100 percent of an area of the surface. The core layer has a first composition. The first layer is a cold-sprayed layer. The core layer has a second composition different from the first composition. The first layer reduces surface-radiated noise from the exhaust component during operation of the motor vehicle. The internal volume is at least partially defined by the wall. The inlet is in fluid communication with the internal volume. The outlet is in fluid communication with the internal volume.

An exhaust heat recovery system may include a muffler including a muffler case, a pipe through which exhaust gas flows, a baffle partitioning an internal space of the muffler case into a first space and a second space, and a valve mounted on an end portion of the pipe to change a direction in which the exhaust gas flows, and a heat exchanger mounted outside the muffler to fluidically-communicate with both the first and second spaces, allowing the exhaust gas to be introduced thereinto and to be discharged therefrom, the heat exchanger including a cooling channel through which cooling water flows, and heat exchange between the exhaust gas and the cooling water being performed in the heat exchanger.