The present disclosure provides a gas turbine combustor including a combustion structure (10) having a combustor liner (14) and a flow sleeve (12). The combustor liner (14) includes inner and outer surfaces (31, 30) and defines a combustion zone (15). The gas turbine combustor further includes a plurality of hollow airfoil-shaped structures (22) affixed to the combustor liner (14) and extending radially outwardly into an airflow space (18) defined radially between the flow sleeve (12) and the combustor liner (14). Each hollow structure (22) includes at least one metering tube (26) providing acoustic communication between the combustion zone (15) and the hollow structure (22). The metering tubes (26) are detachably coupled to the combustor liner (14) for permitting interchanging of the metering tube (26) with at least one additional metering tube having at least one different dimension to effect a change in an acoustic characteristic of the hollow structure (22).

An exhaust-gas aftertreatment device (10) for an internal combustion engine, particularly for a marine diesel internal combustion engine operated using heavy fuel oil, includes a housing (11); an exhaust-gas chamber (12) defined by the housing (11), for permitting exhaust gas to flow continuously through the housing (11), an inlet (13) for permitting exhaust gas to flow into the housing and an outlet (14) for permitting exhaust gas to flow out of the housing (11); a sound damping chamber (15), defined by the housing (11) and coupled with the exhaust-gas chamber (12). The sound dampening chamber (15) is constructed to receive a fluid or a pourable solid at a fill level depending on the frequency of an exhaust sound to be damped.

An exhaust-gas aftertreatment device (10) for an internal combustion engine, particularly for a marine diesel internal combustion engine operated using heavy fuel oil, includes a housing (11); an exhaust-gas chamber (12) defined by the housing (11), for permitting exhaust gas to flow continuously through the housing (11), an inlet (13) for permitting exhaust gas to flow into the housing and an outlet (14) for permitting exhaust gas to flow out of the housing (11); a sound damping chamber (15), defined by the housing (11) and coupled with the exhaust-gas chamber (12). The sound dampening chamber (15) is constructed to receive a fluid or a pourable solid at a fill level depending on the frequency of an exhaust sound to be damped.

An exhaust structure for a straddle-type vehicle includes a muffler having an outer tube constituting an outer circumferential member of the muffler; first and second separators defining expansion chambers in the outer tube; a body end member arranged at the downstream end of the outer tube; and glass wool provided on the inner circumference of the outer tube. The muffler further includes a resonator chamber provided in the most downstream portion of the muffler. The resonator chamber is formed by the outer tube, the body end member and the second separator situated closest to the body end member. The surroundings of the resonator chamber are surrounded by the glass wool. Such exhaust structure of a straddle-type vehicle is capable of taking measures against exhaust heat and exhaust sound even with a configuration where there is only one, single resonator chamber.

An exhaust structure for a straddle-type vehicle includes a muffler having an outer tube constituting an outer circumferential member of the muffler; first and second separators defining expansion chambers in the outer tube; a body end member arranged at the downstream end of the outer tube; and glass wool provided on the inner circumference of the outer tube. The muffler further includes a resonator chamber provided in the most downstream portion of the muffler. The resonator chamber is formed by the outer tube, the body end member and the second separator situated closest to the body end member. The surroundings of the resonator chamber are surrounded by the glass wool. Such exhaust structure of a straddle-type vehicle is capable of taking measures against exhaust heat and exhaust sound even with a configuration where there is only one, single resonator chamber.

The dual function exhaust system attachment, which is preferably used with an all-terrain vehicle, includes a muffler, a silencing cap, and a sound-enhancing plug. In a quiet configuration, the silencing cap is mounted to conceal a primary outlet of the muffler. In a loud configuration, the sound-enhancing plug is mounted to conceal a secondary outlet of the muffler. A set of screw threads or sealing mechanism may be used to mount the silencing cap and the sound-enhancing plug. A primary perforated barrier, a solid barrier, at least one secondary perforated barrier, and a pipe section are positioned within a hollow structural body of the muffler to guide the exhaust gas flow from an inlet of the muffler to the primary outlet or the secondary outlet.

A method for automatically changing the engine exhaust sound in conjunction with the traveling mode implemented by the exhaust system applied to the vehicle may vary the valve opening of an electronic variable valve provided in a first tail pipe of first and second tail pipes of muffler discharging the exhaust gas coming from an engine by a mode recognition logic connected to an engine ECU to the atmosphere, and control the variation of the valve opening with the engine torque and the engine RPM based on a change in an accelerator pedal stroke in any one of a SMART DRIVE MODE-ECO state, a SMART DRIVE MODE-COMFORT state, and a SMART DRIVE MODE-SPORT state, implementing a quiet engine exhaust sound and a sporty engine exhaust sound depending on various vehicle traveling states provided by the SMART DRIVE MODE and increasing vehicle/engine outputs.

A method for automatically changing the engine exhaust sound in conjunction with the traveling mode implemented by the exhaust system applied to the vehicle may vary the valve opening of an electronic variable valve provided in a first tail pipe of first and second tail pipes of muffler discharging the exhaust gas coming from an engine by a mode recognition logic connected to an engine ECU to the atmosphere, and control the variation of the valve opening with the engine torque and the engine RPM based on a change in an accelerator pedal stroke in any one of a SMART DRIVE MODE-ECO state, a SMART DRIVE MODE-COMFORT state, and a SMART DRIVE MODE-SPORT state, implementing a quiet engine exhaust sound and a sporty engine exhaust sound depending on various vehicle traveling states provided by the SMART DRIVE MODE and increasing vehicle/engine outputs.

A muffler for an exhaust system of an internal combustion engine, especially for vehicles with hybrid drive, includes a muffler housing (12), a heat exchanger unit (48), arranged in the muffler housing (12), for transferring heat from combustion exhaust gas to a heat transfer medium, an inlet pipe (38), a first outlet pipe (52) and a second outlet pipe (40). A first exhaust gas flow path (54), in the muffler housing, routs exhaust gas through the heat exchanger unit (48) to the first outlet pipe (52). A second exhaust gas flow path (56), in the muffler housing, routs exhaust gas to a second outlet pipe (40), bypassing the heat exchanger unit (48). A flow path blocking/releasing device (58) for blocking and releasing at least one exhaust gas flow path (54, 56), of the first exhaust gas flow path (54) and of the second exhaust gas flow path (56).

A muffler for a vehicle, where the muffler comprises a partition wall that divides the interior in a first chamber and a second chamber, where an inlet pipe comprising a perforated section arranged in the first chamber and a closed section arranged in the first chamber, where the outlet opening of the inlet pipe is arranged in the second chamber, a first outlet pipe comprising an inlet opening arranged in the first chamber and an outlet opening arranged outside of the muffler, where the muffler comprises a second outlet pipe having an inlet opening arranged in the second chamber, and where the second outlet pipe is provided with an exhaust valve adapted to open or close the exhaust gas flow through the second outlet pipe. The advantage of the invention is that a muffler with an improved low frequency noise attenuation and low backpressure is provided.