An apparatus for regulating pressure of exhaust gas of a fuel cell system includes porous foam mounted in an exhaust tube and having a plurality of pores therein and a regulator that compresses or expands the porous foam to regulate a differential pressure of the exhaust gas flowing through the exhaust tube.

A vehicle exhaust system component includes an exhaust tube defining an exhaust gas flow path, a side branch tuning tube connected to the exhaust tube at an interface, and a porous structure associated with the exhaust tube to reduce noise generated at the interface. In one example, the porous structure comprises a perforated orifice in the exhaust tube. In another example, the porous structure comprises a mesh screen or mesh sleeve.

An apparatus and method are provided for a drone elimination muffler to attenuate drone exhibited by engine exhaust systems. The drone elimination muffler comprises a hollow canister having a length and a diameter, and a tuned port comprising a first end connected to the canister and a second end connected to the exhaust system. The canister operates in concert with the tuned port as a dampener configured to substantially attenuate exhaust drone, or resonance, at one or more frequencies of engine operation. A valve is configured to switch the drone elimination muffler between a closed state in which the exhaust system operates without acoustic influence due to the drone elimination muffler, and an open state in which the drone elimination muffler directly influences the acoustic properties of the exhaust system.

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 pipe is provided with an expansion chamber having an inner diameter that is larger than an inner diameter of the exhaust pipe. At least a part of the expansion chamber is disposed in the muffler main body, and a plurality of through holes are formed on an outer peripheral surface of the expansion chamber disposed in the muffler main body.

An apparatus and method are provided for a drone elimination muffler to attenuate drone exhibited by engine exhaust systems. The drone elimination muffler comprises a hollow canister having a length and a diameter, and a tuned port comprising a first end connected to the canister and a second end connected to the exhaust system. The canister operates in concert with the tuned port as a dampener configured to substantially attenuate exhaust drone, or resonance, at one or more frequencies of engine operation. A valve is configured to switch the drone elimination muffler between a closed state in which the exhaust system operates without acoustic influence due to the drone elimination muffler, and an open state in which the drone elimination muffler directly influences the acoustic properties of the exhaust system.

A muffler with ease discharge of condensate may include a housing formed of a cylinder shape and provided with an end plate at both end portions thereof, at least one baffle disposed in the housing to divide the internal space of housing into a plurality of chambers, an inlet pipe introducing exhaust gas in the housing, an outlet pipe discharging the exhaust gas from the housing the outside, so that the exhaust gas flowed into the inlet pipe flows through the chamber divided in the housing to be discharged through the outlet pipe, a condensate collecting tube disposed along the lower surface of the housing and provided with a passage in which the condensate gathered in the lower surface of the housing is introduced to be flowed and a condensate inducing tube connecting the condensate collecting tube and the outlet pipe.

A snap-action valve assembly for an exhaust system is provided with a conduit that defines an exhaust passageway. A valve flap is disposed within the exhaust passageway for controlling exhaust flow. A shaft supports the valve flap in the exhaust passageway and allows the valve flap to rotate between closed and open positions. A mass damper, positioned outside the conduit, includes a longitudinal segment that is rotatably coupled to the shaft and that extends between first and second coiled ends. The longitudinal segment includes an inboard side and an outboard side. The first and second coiled ends include a series of overlapping layers arranged in either a folded serpentine shape or a spiral shape.

A substantially metal-free exhaust subsystem includes an exterior housing formed of polymer; and a pipe formed of a layered fibers formed at least partially of glass, and bound by an inorganic binder. The fibers may be glass or ceramic, and may define micro-pores on the interior of the pipe that aid in absorbing acoustic energy, and thereby attenuating exhaust noise.

A damping device, in particular for damping or preventing pressure impacts, like pulsations, in hydraulic supply circuits has a damping housing (1) surrounding a damping chamber with a fluid inlet (13) and a fluid outlet (15). A damping tube (21; 51) is located in the flow path between the damping inlet and outlet and has a branch opening (29; 73, 75, 77, 79, 81) passing through the tube wall and leading to a Helmholtz volume (27; 53, 55, 57, 59, 61) inside of the damping housing (1) forming a Helmholtz resonator in a region positioned inside of the length of the damping tube. A fluid filter (35) is arranged inside of the damping housing (1) in the flow path between the fluid inlet (13) and fluid outlet (15).

One aspect of the present disclosure provides an exhaust unit including a housing, a wall member, a catalyst, and a muffler chamber. The housing includes a feed inlet and a discharge outlet. The housing is configured such that an exhaust gas of an internal combustion engine is introduced from the feed inlet, and the exhaust gas is discharged from the discharge outlet. The wall member is disposed in the housing, and forms a cylindrical flow path that guides a flow of the exhaust gas introduced from the feed inlet to curve along an outer circumference of an interior of the housing. The catalyst is disposed in the flow path. The muffler chamber communicates with the flow path in a downstream side of the catalyst in the flow path. The wall member serves as a part of a wall that defines an inside and an outside of the muffler chamber.