An exhaust valve device includes a valve body, a valve seat, a support shaft, a coil spring, and a cushion member. The valve body is placed in an exhaust passage in a silencer, and configured to open and close the exhaust passage. The valve body abuts against the valve seat when the valve body is closed. The support shaft is fixed to the valve seat, and supports the valve body to be able to swing freely. The support shaft is inserted in the coil spring. The coil spring biases the valve body. The cushion member is interposed between the coil spring and the support shaft. The cushion member is rotatable relative to the support shaft.

In order to further improve the sound damping in a refrigerant compressor comprising a common housing, a screw-type compressor in a common housing has a compressor housing that is formed as part of the common housing with a first sound absorber unit which is arranged in the common housing. The first sound absorber unit is arranged adjacent a housing window, and the sound absorber unit comprises at least one chamber which is located between an inlet opening and an outlet opening and which widens out relative to the inlet opening and to the outlet opening in a direction transverse to a direction of flow.

An exhaust device includes an expansion chamber that expands an exhaust gas from an engine; a separator that partitions the expansion chamber; and a plurality of catalyst units arranged in the expansion chamber and supported in parallel by the separator. The separator is divided into upper and lower portions through a dividing plane, and the plurality of catalyst units are supported in such a manner as to be clamped from upper and lower sides at the dividing plane.

The present application provides a mobile selective catalyst reduction system for use at a remote location. The mobile selective catalyst reduction system may include a first trailer with an ammonia delivery system and a tempering air system mounted thereon in whole or in part and a second trailer with a selective catalyst reduction section mounted thereon in whole or in part. The ammonia delivery system, the tempering air system, and/or the selective catalyst reduction section are permanently mounted on the first trailer or the second trailer for use at the remote location.

Methods and systems are provided for a noise mitigating device for a turbocharger compressor. In one example, the noise mitigating device includes a set of perforated rings arranged in a recirculation passage of a compressor casing treatment. The rings of the set of perforated rings may be oriented so that apertures of one ring are offset from apertures of one or more adjacent rings, forcing air to flow through the apertures via a non-linear path while deflecting at least a portion of sounds waves generated in the compressor.

A muffler has a housing enclosing a plurality of chambers. A first flow path extends from an inlet to an outlet passing through a bypass chamber. A flow tube has a plurality of perforations being open to a chamber other than the bypass chamber. A second in flow path passes from the inlet to the outlet without passing through the bypass chamber and passing through the perforations. Exhaust gas is introduced into the muffler via the inlet and discharged therefrom via the outlet. A first portion of the exhaust gas flows from the inlet to the outlet along the first flow path. A second portion of the exhaust gas flows from the inlet to the outlet along the second flow path, the first and second portions mixing at least in the outlet chamber. A semi-closed tube has an open end being open to one of the chambers and a closed end.

An exhaust pipe device of a saddle-riding vehicle, wherein a power unit is fixed to a body frame of a saddle-riding vehicle, includes an upstream-side exhaust pipe device for discharging exhaust gas from an internal combustion engine, a catalyst built-in pipe connected to a downstream end of the upstream-side exhaust pipe device, and a downstream-side exhaust pipe device connected to a downstream end of the catalyst built-in pipe. An exhaust muffler is connected to a downstream end of the downstream-side exhaust pipe device. The downstream-side exhaust pipe device has a main pipe portion and a branch pipe portion on a downstream side of an upstream end thereof where a branching portion is provided. An exhaust control valve is provided to the branching portion where the branch pipe portion is branched from the main pipe portion. The branch pipe portion overlaps, as seen in side view, with a vehicle center-side wall of the main pipe portion, and downstream ends of both the main and branch pipe portions are connected to the exhaust muffler. The above arrangement provides an exhaust pipe device wherein a branch pipe portion can be formed in a compact shape as viewed in side view, whereby excellent external appearance property is obtained, and a valve shaft of the exhaust control valve at the branching portion can be easily arranged with a required banking angle.

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 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 of the length.

Two end caps with metal straight tubing inserted into a muffler canister, Then affixed to a motorcycle header pipes that's connected to a combustion engine, Particularly a motorcycle engine, Where exhaust gas discharges through both creating more engine performance and sound.

A muffler having a movable baffle may include a housing where an input pipe into which exhaust gas is flowed from an engine and an output pipe through which the exhaust gas is expelled to atmosphere are disposed, a baffle which is configured to be slidable along the longitudinal direction of the housing and divides the space of the housing, baffle moving means for moving the baffle to an arbitrary position within a predetermined range along the longitudinal direction of the housing, and a controller which data for determining whether to move the baffle or not is input thereto when the engine is driven, determines whether to move the baffle or not by use of the input data and controls the baffle moving means when the baffle is determined to be moved.