Abstract: A vehicle exhaust system is provided. The exhaust system may include a muffler including a casing, an inlet tube extending therethrough, and an outlet pipe partially disposed therein. The exhaust system may also include an orifice tube that may have a tapered body inserted within an end of the outlet pipe that is disposed between a baffle and a wall of the casing. The orifice tube may also include an inlet portion flared from the tapered body configured to attenuate noise of exhaust gas funneling into the outlet pipe.

Abstract: An inline fluid damper device comprises a flow-through conduit configured to be placed inside a larger exterior conduit through which a fluid flows. The flow-through conduit is elongated and extending around a center axis. The damper device also comprising an indirect flow conduit coupled with the flow-through conduit. The indirect flow conduit is also configured to be placed inside the larger exterior conduit. The flow-through conduit and the indirect flow conduit are configured to dampen one or more flow fluctuations or pressure fluctuations in the fluid flowing in the larger exterior conduit by dividing the fluid into a first portion that flows along the center axis through the flow-through conduit and a second portion that concurrently flows outside of the flow-through conduit along the center axis and along a different direction.

Abstract: A gun barrel sound suppressor incorporating a housing having a breach end, a muzzle end, and a barrel axis extending between those ends; a bullet passage conduit aligned with the barrel axis; a first annular gas outlet port opening the bullet passage conduit; a first annular gas inlet port further opening the bullet passage conduit, the first annular gas inlet port being positioned muzzlewardly from the first annular gas outlet port; a first circumferentially extending “U” channel having a web, having a breachward arm having a distal end, and having a muzzleward arm having a distal end, wherein the distal end of the first breachward arm communicates with the first annular gas outlet port, and wherein the distal end of the first muzzleward arm communicates with the first annular gas inlet port.

Abstract: In one example embodiment, an apparatus may include a panel with integrated fluid channels, wherein the panel and the fluid channel consist only of surfaces that can be manufactured with a straight-pull mold. A port may also be integrated into the panel to facilitate coupling the fluid channel to pneumatic components in an assembly. A seal may be secured to the panel over the fluid channel to form an integrated fluid conductor. The seal is preferably an adhesive label that can also be used for product labeling. Such an apparatus may be used in a control unit of a therapy system, employing several integrated fluid conductors. A method of manufacturing may include molding a panel, wherein the mold forms a channel integral to the panel. The panel and the channel preferably consist of surfaces that can be molded with a straight-pull mold.

Abstract: A powerboat muffler is disclosed that balances decreasing exhaust noise and producing power. A muffler cannister has concentric inlet tubes, forming an inlet baffle, where exhaust gas and engine coolant enters the muffler, a V-shaped baffle within the cannister, a funneled outlet, and concentric outlet tubes, forming an outlet baffle. The inlet baffle comprises concentric outer and inner tubes and the front wall of the muffler, which together form an toroidal inlet space. The inner inlet tube extends a certain distance into the muffler cannister. The inside wall of the inner inlet tube is shaped to create a venturi. Through the front wall, within the toroidal inlet space, small venturi-shaped openings are disposed radially between the outer and inner tubes to allow engine exhaust and coolant to enter the muffler. At the outlet end of the muffler, a tapered nozzle funnels exhaust to an outlet tube with a venturi contour. The outlet tube extends out from the outlet nozzle a certain distance.

Abstract: A pulsation control device coupling a reciprocating pump with either suction or discharge piping and having a generally spherical or cylindrical interior chamber includes a curved baffle with a pressure drop device (e.g., a choke) separating the interior chamber into two volumes and forcing fluid flow through the pressure drop device. The effective fluid passage provided by the pressure drop device is smaller than the fluid passage for one or both of the inlet to and/or the outlet from the interior chamber. Fluid entering the pulsation control device reacts with fluid contained within the volume thereof on both sides of the baffle. The baffle attenuates pressure pulses within fluid passing through the interior chamber in response to operation of the reciprocating pump. The pressure drop device dampens high frequency pulsation magnitudes of pressure pulses within fluid passing through the interior chamber in response to operation of the reciprocating pump.

Abstract: A projectile launching device includes a primary tube having a primary passage for launching a projectile. In some embodiments, the projectile launching device further includes a secondary tube disposed about the primary tube and defining a secondary passage, and a flow apparatus in fluid communication with the secondary passage configured to move gas through the secondary passage. An opening is at the end of the secondary tube and is configured to allow gas to laminarly exit the secondary passage. In other embodiments, the projectile launching device further includes a flow apparatus in fluid communication with the primary passage configured to draw gas from the primary passage to provide at least a partial vacuum in the primary passage. The projectile launching device may provide increased range, accuracy, and velocity of the projectile, in addition to providing a reduced sound signature of the projectile launching device.

Abstract: A silencer having an outer shell with a first opening at a first end is configured with two flow paths and designed to attenuate sound waves. A tube is positioned within the outer shell, the tube having a first end and a second end forming a path through the interior of the silencer. A baffle is positioned between the inner tube and the outer shell to form a second path through the silencer. The first path may be longer than the second path. The sum of the cross-sectional areas of the first path and second path may be equal to the cross-sectional area of the first opening.

Abstract: An attenuation device for a vehicle is provided, including a housing having a chamber formed therein. The housing is coupled to and in fluid communication with an air-conditioning circuit of the vehicle. A dampening member is disposed within the chamber of the housing. The dampening member includes a partition plate having at least one pipe disposed therein. The dampening member is configured to attenuate acoustic energy produced by a fluid of the air-conditioning circuit.

Abstract: A muffler for an internal combustion engine includes an outer shell, an inlet pipe, an outlet pipe, and at least one constricted part. The at least one constricted part is provided in at least one of the inlet pipe and the outlet pipe on an open side thereof opening toward an inside of the outer shell. The at least one constricted part has a cross-sectional area smaller than a cross-sectional area of the at least one of the inlet pipe and the outlet pipe, which is provided with the at least one constricted part.

Abstract: The present teachings provide for an airflow sound suppressor, such as for an HVAC assembly, for example. The sound suppressor includes a first end configured to be mounted to a first surface of the HVAC assembly. A second end of the sound suppressor is configured to be mounted to a second surface of the HVAC assembly. An elongated portion extends between the first end and the second end. The elongated portion defines a passageway therethrough that extends an entire length of the sound suppressor.

Abstract: A low emissions 2-stroke natural gas fueled engine includes at least one cylinder with an exhaust port in communication with a silencer/catalytic converter unit. The unit has first and second volumes in communication with each other. The first volume dampens spurious exhaust pressure excursions and removes particulates in the exhaust. The second volume houses an oxidation catalyst for treating exhaust to reduce exhaust emissions. The engine oil has at most 10 ppm zinc content to reduce metal poisons contained in the exhaust prior to contact with the oxidation catalyst. The engine oil preferably has a very low ash content to minimize sulfur combustion components in the exhaust to reduce masking of the oxidation catalyst. The first volume preferably has a pressure relief valve set to relieve at a pressure greater than the maximum normal operating pressure of the engine to avoid excessive pressure excursions of the engine exhaust from damaging the oxidation catalyst.

Abstract: A muffler comprising an inner pipe having one end connected to an upstream side of an exhaust pipe of an engine exhaust system, and another end connected to a downstream side of the exhaust pipe, an outer pipe covering at least part of the inner pipe, a hole being formed in a pipe wall of the inner pipe, a resonance chamber formed in a space between the inner pipe and the outer pipe, and a connection passage formed on an outer peripheral surface of the inner pipe along an axial direction of the inner pipe. The connection passage comprising a plurality of sections connected in series to form the connection passage as a single continuous passage.

Abstract: An exhaust system for an internal combustion engine, having a first exhaust tract assigned to a first group of cylinders of the internal combustion engine, and having a second exhaust tract assigned to a second group of cylinders of the internal combustion engine, each exhaust tract comprising an exhaust gas purification device, a first silencer arranged on the outlet side of the respective exhaust gas purification device, and a second silencer arranged on the outlet side of the respective first silencer. Each exhaust tract includes a bypass line, it being possible for exhaust gas to be diverted via each bypass line, starting from the respective first silencer, bypassing the second silencers, and the bypass lines and hence the first silencers of both exhaust tracts being connected to one another by a mixing line.

Abstract: A dual exhaust system includes a first exhaust component defining a first exhaust path and a second exhaust component defining a second exhaust path that is different from the first exhaust path. A first valve is associated with the first exhaust path and a second valve is associated with the second exhaust path. The first valve and second valve operate independently of each other to vary exhaust flow and provide sufficient noise control for varying applications.

Abstract: An exhaust system of an internal combustion engine and provided with: at least one first high acoustic attenuation path having a first inlet opening; at least one second low acoustic attenuation path having a second inlet opening; and at least one control valve, which is arranged at the second inlet opening of the second path to control the flow of the exhaust gases along the second path.

Abstract: An exhaust throttle valve protected from disturbance due to stones scattered during operation of a vehicle. Front side exhaust pipes and rear side exhaust pipes are connected to a catalyst chamber disposed below a crankcase. The catalyst chamber and an exhaust chamber disposed to the rear thereof are connected to each other via a rear exhaust pipe. The diameter of the rear exhaust pipe is smaller than the lateral width of each of the catalyst chamber and the exhaust chamber, so that a recessed space is externally formed so as to recede inside of the vehicle. An exhaust throttle valve is received in the space. The exhaust throttle valve is partially exposed to the outside of the rear exhaust pipe and a throttle valve is received in the rear exhaust pipe to throttle-control the passage-sectional area of the rear exhaust pipe according to the rotation of the engine.

Abstract: A system for reducing an acoustic load of a fluid flow includes a first pipe to carry the fluid flow; a standpipe connected to the first pipe at an opening in the first pipe; and a standpipe flow tripper provided in the standpipe. The flow tripper includes an edge extending through the opening into the flow on a downstream side of the opening. A method of reducing an acoustic load of a standing wave in a standpipe connected to a first pipe configured to carry a flow includes disrupting the flow in the first pipe at a downstream side of an opening in the first pipe to which the standpipe is connected.

Abstract: A system for reducing an acoustic load of a fluid flow includes a first pipe. The first pipe includes a first end and a second end and a first aperture and a second aperture, the first and second apertures being intermediate the first and second ends. A second pipe includes a first end and a second end and a third aperture intermediate the first and second ends. The second pipe is connected at its first end to the first pipe at the first aperture. A bypass pipe includes a first end connected to the second aperture of the first pipe and a second end connected to the third aperture of the second pipe. A method of reducing an acoustic load of a flow in a standpipe connected to a first pipe configured to carry a main flow includes providing a bypass flow from the first pipe to the standpipe.

Abstract: The invention relates to a silencer for an airborne sound conducting pipe system, including a housing enclosing an interior space, an inlet pipe having an outlet within the interior space, a bypass pipe branching off from inlet pipe within the housing and having an outlet, a control element actuated by the gas flow and arranged downstream of bypass pipe on or in the inlet pipe, and at least one outlet pipe having an inlet within the interior space. Furthermore, the interior space is acoustically unseparated in such a manner that the volume of the interior space loaded with the airborne sound is equal with opened and with closed control element.

Abstract: An exhaust system (1) is provided for an internal combustion engine (4), especially in a motor vehicle, with two separate exhaust gas lines (2, 3) with a first sound transmission feature (7), which couples the two exhaust gas lines (2, 3) with one another, and with a control (9) for activating and deactivating the first sound transmission connection (7) as a function of at least one operating parameter of the internal combustion engine (4).

Abstract: A low emissions 2-stroke natural gas fueled engine includes at least one cylinder with an exhaust port in communication with a silencer/catalytic converter unit. The unit has first and second volumes in communication with each other. The first volume dampens spurious exhaust pressure excursions and removes particulates in the exhaust. The second volume houses an oxidation catalyst for treating exhaust to reduce exhaust emissions. The engine oil has at most 10 ppm zinc content to reduce metal poisons contained in the exhaust prior to contact with the oxidation catalyst. The engine oil preferably has a very low ash content to minimize sulfur combustion components in the exhaust to reduce masking of the oxidation catalyst. The first volume preferably has a pressure relief valve set to relieve at a pressure greater than the maximum normal operating pressure of the engine to avoid excessive pressure excursions of the engine exhaust from damaging the oxidation catalyst.

Abstract: The invention relates to a piston engine comprising a rotatably mounted cylindrical drum (2) provided with a plurality of cylindrical boreholes distributed over the circumference thereof and containing displaceable pistons. Said cylindrical boreholes (3,4) comprise cylindrical openings (35.1, 35.2, . . . 35.9) on one side, which are temporarily connected to one of two control nodules (9, 10) according to the angle of rotation of the cylindrical drum (2), said control nodes being respectively connected to a working line (27, 28). A reversing region (30, 31) is respectively embodied between the control nodules (9, 10), a first end (32) of a pressure compensation line (33) ending in one of the reversing regions (30, 31).

Abstract: A muffler assembly includes first and second muffler components that are each formed as a single piece. The first muffler component includes a first outlet pipe portion, a first bypass pipe mount portion, and a first resonator shell portion. The second muffler component includes a second output pipe portion, a second bypass pipe mount portion, and a second resonator shell portion. The first and second muffler components are positioned in an overlapping relationship such that respective portions are aligned with each other to form an outlet pipe, a bypass pipe mount, and a resonator shell. A noise attenuation valve assembly is also installed within the first and second muffler components. The bypass pipe mount is positioned at a non-perpendicular orientation relative to the outlet pipe such that a bypass pipe having a straight end mount can be received within the bypass pipe mount to bypass the noise attenuation valve assembly.

Abstract: A passive valve assembly for a vehicle exhaust system includes an exhaust component that defines an exhaust gas flow path and a vane that is positioned within the exhaust gas flow path. The vane is movable between a fully closed position where a maximum portion of the exhaust gas flow path is blocked by the vane and a fully open position where a minimum portion of the exhaust gas flow path is blocked by the vane. The closed position comprises a start position for the passive valve assembly when there is no exhaust gas flow. The vane is obliquely orientated to a plane that is perpendicular to a centerline of the exhaust component when the vane is in the start position.

Abstract: An exhaust component includes a wall with an inner surface defining an exhaust gas flow path. A passive valve assembly includes a vane that is positioned within the exhaust gas flow path to be pivotable between open and closed positions. The vane is defined by a plane that extends across a width of the vane. The vane is supported by a shaft that defines an axis of rotation. The axis of rotation is offset from the plane of the vane such that the vane can be pivoted to a fully open position without interfering with the inner surface of the wall.

Abstract: The invention uses tubes for the reduction of radiated duct noise. The tubes may be used to attenuate narrow band noise by diverting a portion of the acoustic energy through the tubes back into the duct. Upon reintroducing the diverted flow out of phase with the primary flow, acoustic cancellation is achieved. The frequency at which this occurs is dependent on the difference in the path lengths through the tubes and the separation distance—the distance separating the inlet and outlet of the tube. This invention can be used over varying frequency ranges by using an arrangement of flexible, constant length tubes. The effective frequency range is tailored by varying the separation distance and also allows the varying the angular arrangement of the tubes for more effective attenuation of spinning modes having varying propagation angle.

Abstract: The invention relates to a muffler for an exhaust system of an internal combustion engine, consisting a housing having at least one exhaust inlet and at least one exhaust outlet and having at least two pipes at the inlet end or at the outlet end, at least one of which is switchable by a control device at least between an open state and a closed state and is acoustically coupled to a silencer system, such that the silencer system is active when the switchable pipe is opened as well as when it is closed and has a different damping characteristic when the switchable pipe is opened than when the switchable pipe is closed.

Abstract: A reflecting plate type silencer pipe including a reflecting plate is provided for reducing a dominant frequency noise passing through a pipeline. Sound waves propagated in the pipeline as a one-dimensional plane wave are divided into two, that is, sound waves advancing straight along the pipeline and sound waves caused to pass through a bypass route by the reflecting plate thereby being delayed in phase. Both of the sound waves are joined again so as to synchronously advance in the same direction and in parallel to each other with the sound waves being the same in amplitude and opposite in phase to each other, and wave interference is effected between the sound waves, whereby wave propagation energy of the sound wave of the frequency to be silenced passing through the pipeline is selectively dissipated.

Abstract: The invention uses tubes for the reduction of radiated duct noise. The tubes may be used to attenuate narrow band noise by diverting a portion of the acoustic energy through the tubes back into the duct. Upon reintroducing the diverted flow out of phase with the primary flow, acoustic cancellation is achieved. The frequency at which this occurs is dependent on the difference in the path lengths through the tubes and the separation distance—the distance separating the inlet and outlet of the tube. This invention can be used over varying frequency ranges by using an arrangement of flexible, constant length tubes. The effective frequency range is tailored by varying the separation distance and also allows the varying the angular arrangement of the tubes for more effective attenuation of spinning modes having varying propagation angle.

Abstract: A fuel cell system with a muffler to reduce noise generated while supplying air to a fuel cells disclosed. One embodiment of the fuel cell system includes an air feeder to supply air; an electric generator to generate electricity through an electrochemical reaction between air and fuel; and a muffler provided in one end of the air feeder. The muffler includes a first pipe and a second pipe which are different in length from each other. The muffler has a relatively small structure, so that limitation in a mounting space can be decreased and a more compact fuel cell system can be realized. Also, even if there are considerable noise components at two or more frequencies, the mufflers corresponding to the respective frequencies are connected in series, thereby reducing the noise.

Abstract: A system and method for dissipating at least one pressure wave in an exhaust gas flow is disclosed. A vehicular exhaust system directs the exhaust gas flow through a plurality of coaxial and perforated generally cylindrical tubes contained within an insulated canister towards a perforated partition plate. Through a series of apertures in the tubes and plate, the at least one pressure wave is dissipated such that sound attenuation is achieved without output loss from the engine.

Abstract: A low emissions 2-stroke natural gas fueled engine includes at least one cylinder with an exhaust port in communication with a silencer/catalytic converter unit. The unit has first and second volumes in communication with each other. The first volume dampens spurious exhaust pressure excursions and removes particulates in the exhaust. The second volume houses an oxidation catalyst for treating exhaust to reduce exhaust emissions. The engine oil has at most 10 ppm zinc content to reduce metal poisons contained in the exhaust prior to contact with the oxidation catalyst. The engine oil preferably has a very low ash content to minimize sulfur combustion components in the exhaust to reduce masking of the oxidation catalyst. The first volume preferably has a pressure relief valve set to relieve at a pressure greater than the maximum normal operating pressure of the engine to avoid excessive pressure excursions of the engine exhaust from damaging the oxidation catalyst.

Abstract: A powertrain control system is provided that includes an engine having multiple cylinders. A controller selectively activates the cylinders to provide a cylinder combination having a desired power displacement. In one example powertrain control system, the controller selectively activates the cylinders between a V-8 and V-4 mode. An exhaust system having a valve and an electrical actuator selectively electrically actuates the valve in response to the controller between multiple positions. The electrical actuator moves the valve from an open position in V-8 mode to a partially closed position in V-4 mode to increase back pressure and reduce NVH issues in V-4 mode. A muffler includes a housing having an exhaust passage. The valve is supported by the housing and arranged in the exhaust passage. The valve is moveable between multiple positions for tuning the muffler. The electrical actuator is supported by the housing to actuate the valve between the multiple positions.

Abstract: In an exhaust system, exhaust manifolds are connected to two banks provided in a V-type engine of a vehicle, respectively, to which front pipes each having a catalytic converter are connected to the exhaust manifolds, respectively. A muffler is provided at an exhaust downstream side of the exhaust pipes, and a rear pipe is further connected to the exhaust downstream side of the muffler. The front pipe has its rear end portion located near a through hole formed in the rear pipe. A path length of one of the front pipes from the bank to the muffler is made shorter than that of the other front pipe.

Abstract: An assembly useful in reducing aircraft engine noise such as turbofan engine noise (730) comprises: (1) at least one tube “H-Q” having an inlet end (738), an outlet end (740) and a central tube portion therebetween; an (ii) at least one actuator operatively interconnected to at least one tube, wherein the actuator is capable of causing dynamic response by the tube. The assembly of this invention may be used in a method for reducing noise, the method comprising: (a) providing means for generating non-uniform noise energy about an inner surface and within a disclosure having at least an inlet; (b) providing an assembly for reducing noise comprising; (i) at least one tube having an inlet end, an outlet end and a central tube portion therebetween, and (ii) at least one actuator operatively interconnected to at least one tube, wherein the actuator is capable of causing dynamic response by the tube; and (c) directing at least a portion of the non-uniform noise into the assembly.

Abstract: A noise control apparatus for a motorcycle exhaust system. The apparatus includes at least one exhaust pipe assembly having a direct pass-through mode and an indirect mode wherein exhaust gases are optionally directed through noise attenuating means. The apparatus includes at least one valve for controlling exhaust gas flow, a motor, a switch controlling said motor, a wire carrier, a wire connected between the carrier and the valve(s), and a rotary threaded drive shaft driven by the motor for moving the positioner. The threaded drive shaft includes radially extending and circumferentially facing stop means on both sides of said wire carrier. The valve is positioned under the control of the switch.

Abstract: A muffler has a main body, and an inner shell spaced radially inwardly of the main body by an annular volume therebetween. The inner shell has an internal volume radially inward of the annular volume. The muffler has primary and secondary parallel paths therethrough, with the primary path extending through the internal volume, and the secondary path extending through the annular volume.

Abstract: A sound damping device (4) for a tubular duct (2), particularly a gas transporting tract of an internal combustion engine (1) having a least one bypass channel (5) running parallel to a main duct (6) in a section of the duct (2). The bypass channel (5) is longer than the main duct (6) between a branching off point (7) and a re-entry inlet (8). The bypass duct according to the invention is configured as a spiral duct (5) which winds around the centrally disposed main duct (6) in order to decrease the installation space requirements for the noise suppressor (4).

Abstract: An assembly useful in reducing aircraft engine noise such as turbofan engine noise (730) comprises: (i) at least one tube “H-Q” having an inlet end (738), an outlet end (740) and a central tube portion therebetween; and (ii) at least one actuator operatively interconnected to at least one tube, wherein the actuator is capable of causing dynamic response by the tube. The assembly of this invention may be used in a method for reducing noise, the method comprising: (a) providing means for generating non-uniform noise energy about an inner surface and within a disclosure having at least an inlet; (b) providing an assembly for reducing noise comprising; (i) at least one having an inlet end, an outlet end and a central tube portion therebetween, and (ii) at least one actuator operatively interconnected to at least one tube, wherein the actuator is capable of causing dynamic response by the tube; and (c) directing at least a portion of the non-uniform noise into the assembly.

Abstract: Exhaust system assemblies employ wire bushings for thermal compensation to minimize noise due to “stick-slip” while the system cools. In a preferred embodiment, the wire bushings are formed of at least one strand of wire coiled about male end portions of pipe sections used in the system, each of which male end portions are inserted into a female end portion and held therein by an interference fit. The strand of wire is spot welded at spaced locations to the male end portions to provide bearing surfaces between the spot welds that move slightly as the exhaust system heats and cools to relieve thermal stress in small, substantially inaudible increments.

Abstract: In a muffler device of a motor vehicle, with a plurality of mufflers and an actuator for changing the flow resistance to the exhaust gases flowing through the mufflers, in order to change the damping characteristic, the actuator is provided in a pipe branch having an inlet and two outlets, each outlet being connected via a pipe to a muffler, and the throughflow cross section of the inlet being variable by means of the actuator.

Abstract: An HQ tube arrangement suitable for packaging within a vehicle may be designed by creating a mathematical model representing a tube arrangement having a first passageway and a second passageway fluidly connected to the first passageway at first and second junctions. The second passageway is divided by the junctions into first, second, and third passages. Lengths are associated with each of the first passageway and the first, second, and third passages. A filter parameter, based upon an average transmission loss for a particular frequency over a standard deviation, is analyzed as a function of the lengths. Lengths are chosen based upon analysis of the filter parameter. Portions of the outer walls of the first and second passageways may be secured to or common to one another so that lengths of the passageways run along side of each other to provide a more compact HQ tube arrangement.

Abstract: A fan shroud includes a fan shroud portion having a surface including an aperture. A cooling fan is supported proximate to the aperture for permitting air flow through the fan shroud from the environment to the engine compartment. An air intake portion is supported on the fan shroud portion. The air intake portion and the fan shroud portion together define at least a portion of an air passageway having an inlet for receiving ambient air and an outlet for connection to an engine throttle. The fan shroud portion and air intake portion may respectively include first and second circumferential portions that define the air passageway.

Abstract: A device for noise structuring in a motor vehicle has a plurality of gas-carrying lines connected to an internal combustion engine. At least two of the gas-carrying lines are acoustically linked together by at least one connection.

Abstract: A vertical mount muffler (40) has an external water trap (52) in an exhaust pipe (48) and drains water from a point between the muffler housing upper outlet (46) and the terminal end (50) of the exhaust pipe. The water trap (52) is laterally adjacent to the muffler housing (42) and below the housing upper outlet (46) and traps and drains water entering the exhaust pipe (48) from the terminal end (50).

Abstract: An assembly useful in reducing aircraft engine noise such as turbofan engine noise (730) comprises: (i) at least one tube “H-Q” having an inlet end (738), an outlet end (740) and a central tube portion therebetween; and (ii) at least one actuator operatively interconnected to at least one tube, wherein the actuator is capable of causing dynamic response by the tube. The assembly of this invention may be used in a method for reducing noise, the method comprising: (a) providing means for generating non-uniform noise energy about an inner surface and within a disclosure having at least an inlet; (b) providing an assembly for reducing noise comprising; (i) at least one having an inlet end, an outlet end and a central tube portion therebetween, and (ii) at least one actuator operatively interconnected to at least one tube, wherein the actuator is capable of causing dynamic response by the tube; and (c) directing at least a portion of the non-uniform noise into the assembly.

Abstract: A muffler comprises a casing and an exhaust pipe penetrating the casing. An exhaust gas chamber 4 is defined between the outer wall surface of the exhaust pipe and the inner wall surface of the casing. In the exhaust pipe positioned in the casing, an enlarged chamber for accommodating a particulate filter is formed. A downstream side portion of the exhaust pipe and the exhaust gas chamber are communicated with each other by a branch pipe. A communicating port is formed on the wall of an upstream side portion of the exhaust pipe positioned in the exhaust gas chamber. Until the pressure difference between the upstream and downstream of the communication control valve reaches a threshold value, the communication control valve is kept closed to close the communicating port and, thus, the exhaust gas flows through the particulate filter.

Abstract: An apparatus for controlling exhaust noise in an internal combustion engine uses the length difference between the exhaust pipe and the bypass pipe. The apparatus includes an exhaust pipe for outwardly releasing exhaust gas from the engine; a bypass pipe variable in length which diverges from said exhaust pipe with a distance and has U-shaped and reverse U-shaped sections formed alternately; an actuator having an actuating rod connected to the bypass pipe to vary the length of the bypass pipe; and a control unit for controlling the actuator. The bypass pipe has the U-shaped and reverse U-shaped sections arranged alternately so that the variable length of the bypass pipe can be extended while minimizing the space for installing the bypass pipe, and thereby noise in the low frequency band can be suitably reduced. Also, the exhaust pipe is additionally provided with a device for adjusting the length to increase the length difference with the bypass pipe so that noise in a wider band can be controlled.

Abstract: The invention concerns an exhaust silencer arrangement with integrated bypass assembly and external actuator to control the position of the bypass assembly. For applications where a heightened loudness, or increased horsepower through the decrease of exhaust noise suppression is desired or required, but at temporary instances, the invention allows for real time electronic control over the loudness and horsepower potential of the internal combustion engine to which it is applied. The invention is comprised of the exhaust muffler with integrated bypass and silencer module, external electronic actuator, and the mechanical cable which transmits the mechanical output of the actuator to the bypass valve of the exhaust muffler assembly. The exhaust muffler is comprised of the housing which contains the bypass tube and valve assembly, silencer module, and inlet and outlet chambers which intersect the bypass assembly with the silencer module.