Abstract: An air intake duct includes a peripheral wall, which is formed by a compressed fiber portion made of a compression molded fiber material. The compressed fiber portion includes high-compression portions having a high compression ratio and low-compression portions having a relatively low compression ratio. The high-compression portions include circumferentially extending sections. Each circumferentially extending section is located in a plane that is perpendicular to an extension direction of the peripheral wall with part of the circumferentially extending section disposed between the low-compression portions. Each circumferentially extending section extends continuously over the entire circumference of the peripheral wall.

Abstract: An engine system and method of operating the same includes a two stroke engine, an exhaust manifold coupled to the two-stroke engine, a tuned pipe coupled to the exhaust manifold coupled to the exhaust manifold, a stinger pipe coupled to the tuned pipe, a silencer coupled to the tuned pipe and an exhaust pipe, and an exhaust bypass valve. Exhaust gases are directed from the two stroke engine through an exhaust manifold and through a tuned pipe. An opening of the exhaust bypass valve is changed to redirect exhaust gases away from the tuned pipe to change a pressure within the tuned pipe. In response to changing the opening of the exhaust bypass valve, the airflow through the engine is changed.

Abstract: An engine control device controls an engine. The control device includes a controller. The controller is configured to open the air bypass valve of the engine and close the waste gate valve of the engine when a first condition is satisfied, and thereafter determine that an execution condition of a boost pressure increase control is satisfied when a second condition is satisfied. The air-bypass valve disposed on an air-bypass passage that communicates between an upstream side and a downstream side of a compressor in an intake passage. The waste gate valve disposed on a waste gate passage that communicates between an upstream side and a downstream side of the turbine in an exhaust passage. The first condition represents a turbine pre-rotation start request, and the second condition represents a boost pressure increase request.

Abstract: An exhaust gas turbocharger system (1) has a first and second exhaust gas turbochargers (2, 3) arranged in parallel. Each exhaust gas turbocharger (2, 3) has an exhaust gas turbine (20, 30) and a compressor (21, 31). Fresh air compressed by the compressor (21) of the first exhaust gas turbocharger (2) can flow into a first pressure line (15), and fresh air compressed by the compressor (31) of the second exhaust gas turbocharger (3) can flow into a second pressure line (16). The two pressure lines (15, 16) are connected to each other in terms of flow. An electric drive device (10) is connected to the first exhaust gas turbocharger (2) and can be turned on for providing additional torque for driving the exhaust gas turbine (20) and the compressor (21) of the first exhaust gas turbocharger (2).

Abstract: The present invention provides an exhaust gas pressure control valve which allows discharge of exhaust gases from entire cross-sectional area of the exhaust gas pipeline when the exhaust gas pressure control valve completely. An exhaust gas pressure control valve is mounted on a gas pipeline having a first cross-section where exhaust gas from engine communicates and disposed upstream or downstream of a muffler. The exhaust gas pressure control valve comprises: a housing having a first cross-sectional surface and a second cross-sectional surface larger than the first surface and connected to the gas pipelines for communicating the exhaust gas; the valve axis supported along the second cross-section not overlapping with the first cross-section when viewed from the flowing direction, the valve axis supported by the housing in a crossing direction to the flowing direction; and a valve element connected to the valve axis and adjusts flow of the exhaust gas communicating to the gas pipeline.

Abstract: A selectively tunable exhaust noise attenuation device includes a body having an outer surface and an inner surface that defines an exhaust volume. An inlet is coupled to the body and fluidically connected to the exhaust volume. A first outlet is coupled to the body and fluidically connected to the inlet and selectively fluidically connected to the exhaust volume and a second outlet coupled to the body and fluidically connected to the exhaust volume. A first conduit including a primary exhaust gas flow path directly fluidically connects the inlet and the first outlet. A second conduit includes a first end and a second. The second conduit defines a secondary exhaust gas flow path. A valve is fluidically connected to one of the first and second conduits. The valve is arranged laterally off-set of the primary exhaust gas flow path.

Abstract: A silencer comprises a casing, an inlet pipe for introducing an exhaust into the casing, and an outlet pipe for discharging the exhaust out of the casing. A lid is provided at an exhaust inflow side opening of the outlet pipe and arranged to close the exhaust inflow side opening. The lid has an exhaust inlet for flowing the exhaust into the outlet pipe, a valve body for opening and closing the exhaust inlet, and at least one communication hole formed separately from the exhaust inlet. The valve body is configured to be rotationally movable about a rotation axis of the valve body inside the outlet pipe. The at least one communication hole is provided closer to the rotation axis of the valve body than the exhaust inlet.

Abstract: The dual resonator chamber with variable volume includes first and second housings. The second housing is slidably mounted within the first housing such that a second inner neck portion of the second housing is slidably mounted about the first inner neck portion of the first housing and forms a fluid-tight seal therewith. A sliding wall is slidably mounted within the second housing, dividing the interior thereof into upper and lower resonator chambers. At least one first actuator selectively adjusts the height of the sliding wall with respect to the second lower end of the second housing to selectively adjust volumes of the upper and lower resonator chambers. At least one second actuator selectively adjusts the height of the second housing with respect to the first housing to selectively adjust the neck length of the lower resonator chamber.

Abstract: There is provided an air intake duct capable of fully achieving intake-air noise attenuation effect. The air intake duct has a duct wall section formed of resin in form of tube and configured to introduce external air into an internal combustion engine or alternate power supply system. The duct wall section is provided with a silencing member formed of a lamination of a surface layer formed of a non-woven fabric to which thermosetting resin is impregnated and a ventilation adjusting layer formed of an extendable paper material having a surface in which a plurality of concave and convex portions are formed, and the silencing member includes at least one pair of the surface layers on front and back surfaces of at least one pair of the ventilation adjusting layers, and an intermediate layer is formed between the paired ventilation adjusting layers, the intermediate layer being formed of a same material as that of the surface layer.

Abstract: A variable valve apparatus includes: a housing having a pair of shaft holes and a gate hole formed in the housing; a gate provided to selectively open the gate hole; a shaft provided in the shaft holes and connected to the gate; and a spring provided on the shaft so as to elastically support the gate, in which a gap is formed between the gate and the housing. The variable valve apparatus may be provided as part of a muffler installed in a vehicle.

Abstract: An exhaust flow control valve includes: a valve plate hinged to a downstream exhaust pipe to be pivotable, inside the pipe, between a fully closed position where a short-cut hole is closed and a fully open position where the short-cut hole is opened, the valve plate having a tip end directed toward a downstream side of the downstream exhaust pipe when at the fully open position; a spring receiving member provided to the downstream exhaust pipe to traverse the short-cut hole; and a valve spring having one end portion fastened to a tip end portion, which is located on the downstream side of the downstream exhaust pipe with respect to the spring receiving member, of the valve plate, and having an opposite end side being slidably in pressure contact with the spring receiving member, thereby generating a repulsive force to bias the valve plate toward the fully closed position.

Abstract: The present invention provides a method of and apparatus for, reducing noise caused by the interaction of airflow between two bluff bodies which are in a generally tandem arrangement, the method comprising providing flow control such that the peak turbulence is at least partially displaced from, or reduced at, the surface of the downstream body. The invention also provides an aircraft noise reduction device, and a method of using such a device, comprising a flow control apparatus (2) arranged to be positioned downstream of a flow-facing element (1), wherein the flow control apparatus is arranged, in use, to reduce noise induced by unsteady flow downstream of the flow-facing element, and wherein the flow control apparatus (2) is arranged to be moveable in relation to the flow-facing element (1) between a stowed position and a deployed position.

Abstract: A muffler is disclosed. In the muffler a throttling device that is controlled by the energy of the airflow to be muffled is provided in a pipeline of the airflow that needs to be muffled. The muffler is adjusted by itself according to random variety of the pulsing airflow, and can eliminate or reduce effectively the pulsation of the airflow and the related noise in the range of the low frequency and the middle frequency. The muffling effect of the muffler has no correlation with the volume of the muffler, and therefore the volume of the muffler can be reduced.

Abstract: A muffler is disclosed. In the muffler a throttling device that is controlled by the energy of the airflow to be muffled is provided in a pipeline of the airflow that needs to be muffled. The muffler is adjusted by itself according to random variety of the pulsing airflow, and can eliminate or reduce effectively the pulsation of the airflow and the related noise in the range of the low frequency and the middle frequency. The muffling effect of the muffler has no correlation with the volume of the muffler, and therefore the volume of the muffler can be reduced.

Abstract: An air intake system for reducing air induction noise, which includes an air duct housing that has a lower shell and an upper shell, each having a first end and a second end and a plurality of tuning holes formed therein. The air intake system further includes an air duct that is connected to the air duct housing and includes a circumferential wall having an interior surface and an exterior surface. The circumferential wall defines an aperture between a first end and a second end. A venturi is formed between the first and second ends and restricts the amount of sound passing from the first end to the second end of the air duct. The circumferential wall has a predetermined thickness that enables sound to pass through the circumferential wall and into the air duct housing.

Abstract: A dual-mode exhaust system includes a housing with an input port attached to the existing muffler exhaust system and positioned downstream thereof. The system further includes a mechanism for selectively distributing vehicle exhaust from the input port to the first and second output ports, upper and lower chambers vertically stacked within the housing, and first and second vertically spaced pendulum arms disposed within the upper and lower chambers respectively and anchored at respective distal ends thereof respectively. First and second vehicle exhaust pipes are coupled to the first and second output ports.

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 muffler of a work machine in the form of an engine blower includes: a muffler body; and a diffuser that covers an exhaust outlet of exhaust gas provided on the muffler body. The diffuser has a diffusion space to diffuse the exhaust gas and an exhaust surface on which a plurality of exhaust circular holes are provided to exhaust the exhaust gas to an outside. An opening ratio provided by the exhaust holes of the exhaust surface is gradually increased from a portion corresponding to the exhaust opening toward an outer periphery of the exhaust surface.

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 box type silencer unit includes a ventilation portion, a silencer portion adjacent to the ventilation portion, and a dividing partition located between the ventilation portion and the silencer portion. The ventilation portion is formed of a ventilating passage opened through a front end and a back end of the box body. The silencer portion is formed by closing the front end and the back end of the box body and includes at least one partition plate to make a plurality of silencing passages of different length. Each of the silencing passages communicates with the ventilation passage through at least one opening formed in the dividing partition and at least one of those silencing passages is provided with at least one passage extending partition to extend the length of the silencing passage. This device can be applied to such a portion, e.g., the front grille or bumper of an automobile as cannot take a large area in front of the ventilation or a depth in the ventilating direction.

Abstract: An easily controlled exhaust pipe has a manifold. One end of the manifold is connected to a distal end of a connecting tube. Another ends of the manifold are extended with a first branch tube and a second branch tube. The first branch tube is connected to a first outer tube and the second branch tube is connected to a second outer tube. The second branch tube has a controllable valve. Glass fibers and stainless steel and cotton structure are filled in the first and second outer tubes. A connecting piece welded between the first outer tube and the second outer tube. The controllable valve having a valve seat and washers. The valve seat controlled by a controller.

Abstract: A Helmholtz resonator (24, 24′, 24″, 24a), which is screened in an acoustically transparent manner from the flow (S) by means of an absorption noise suppressor (36) is located on the flow duct (16) in order to suppress the low frequencies in an exhaust gas system (10) for industrial gas turbines with an exhaust gas conduit (12) and a chimney (14) which is connected to it, which together form a continuous flow duct (16).

Abstract: A valve seat structure is secured to an outlet end of a passing pipe installed in an exhaust muffler. The valve seat structure includes a flat seat surface portion which extends around the outlet end of the passing pipe. A valve plate structure is pivotally connected to the valve seat structure. The valve plate structure includes a valve plate portion and a flat sealing portion which forms a peripheral part of the valve plate portion. The valve plate structure has a close position wherein the valve plate portion closes the outlet end of the passing pipe having the flat sealing portion entirely pressed against the flat seat surface of the valve seat structure and an open position wherein the valve plate portion opens the outlet end of the passing pipe having the flat sealing portion separated from the flat seat surface. A biasing structure biases the valve plate structure to assume the close position.

Abstract: A device for silencing a flowing gas which includes a valve housing in which a valve is mounted. A separate pressure regulator is provided which is in communication with the flowing gas and which is responsive to gas pressure to thereby influence movement of a mechanical actuating device which controls movement of the valve such that the valve may be opened at least two different rates dependent upon the pressure of the flowing gas.

Abstract: A sound adjustable tail pipe structure includes an adjuster secured in a rear section of a tail pipe which defines a first oblong slot. The adjuster includes a tube having a first end provided with a first positioning base and a second end provided with a second positioning base, and an adjusting base rotatably mounted in the second positioning base. The first positioning base defines a first through hole connecting to the tube and has a wall defining a plurality of first guide holes. The second positioning base defines a second through hole connecting to the tube and has a wall defining a plurality of second guide holes, and a peripheral wall defining a second oblong slot. The adjusting base defines a third through hole connecting to the second through hole and has a wall defining a plurality of third guide holes aligning with each of the second guide holes, and a peripheral wall defining a screw hole.

Abstract: A controllable exhaust system of an internal combustion engine is shown which includes an exhaust gas inlet tube extending from the engine, a muffler connected at its inlet side to the exhaust gas inlet tube and having first and second exhaust gas flowing passages defined therein, and first and second exhaust gas outlet tubes respectively connected to the first and second exhaust gas flowing passages and extending from the muffler independently. A muffler controller is incorporated with the exhaust system for varying the flow passage area of the second exhaust gas outlet tube in accordance with the pressure of the exhaust gas led into the muffler from the engine.

Abstract: An exhaust system in an internal combustion engine includes a flow rate regulating valve which is positioned in an intermediate portion of an exhaust gas flow passage. The flow rate regulating valve has a rotary shaft rotatably supported in a valve housing, and a rotationally biasing spring mounted between the rotary shaft and the valve housing which provides a spring force to rotationally bias the rotary shaft. In the exhaust system, an axially biasing spring is mounted separately from the rotationally biasing spring between the valve housing and the rotary shaft for biasing the rotary shaft in an axial direction. The rotary shaft is provided with an abutment surface which faces in the one axial direction, and the valve housing is provided with a limiting portion which abuts against the abutment surface to limit the axial movement of the rotary shaft.

Abstract: A butterfly valve adapted to be arranged in a pipe through which fluid can flow, the pipe having an axis and an outlet end, the valve comprising a valve shaft having an axis eccentric to the pipe axis, and a valve element integrally supported by the valve shaft. The valve is opened by a fluid pressure acting on the valve element. A part of the valve element on one side of the valve shaft has a tip portion bent along a pleat line substantially parallel to the shaft axis toward the upstream side of a fluid flow. The valve is arranged at the outlet end of the pipe to form a clearance between the valve element part around the pleat line and the outlet end of the pipe, to thereby allow the fluid to flow out through the clearance, when the valve opens from a closed position thereof.

Abstract: An inlet or exhaust line for a reciprocating machine attenuates the sound level of the machine while being simple and economical to produce. A sensor measures the instantaneous flow rate of gases passing through the line while a restriction device variably restricts the cross-section of the line as a function of the instantaneous flow rate measured by the sensor. Material for absorbing acoustic energy covers the internal wall of the line.

Abstract: A resonator type silencer in which the resonance frequency is variable in accordance with engine speed of an automotive engine. The silencer is comprised of a casing connected through a neck section to a duct through which intake air or exhaust gas flows. A cylindrical rotatable member is disposed in the casing and rotatably supported on a rotatable shaft, forming an annular space between it and the inner peripheral surface of the casing. A stationary partition wall is fixedly disposed inside the cylindrical rotatable member and extends radially. A movable partition wall is disposed in the casing and extends from the rotatable shaft to the cylindrical rotatable member. The movable partition wall defines, in cooperation with the stationary partition wall, a tuning chamber inside the cylindrical movable member. A movable blocking wall is disposed in the casing to block the annular space thereby to define a peripheral passage in communication with the neck section.

Abstract: A pulsation damper and noise attenuator assembly comprising a housing having an inlet port and an outlet port fluidly connecting the interior of the housing to the flow path of the fluid flow system. A base is mounted to the housing and comprises a vent fluidly connecting the interior of the housing to the atmosphere. A piston seated within the housing creates a fluid tight seal between the fluid flow path and the vented atmospheric pressure. Belleville springs bias the piston in a forward direction. The piston absorbs the full force of the hydraulic shock waves or pulsation within a high pressure fluid flow system as the assembly is mounted directly within the flow path of the fluid. The shock wave is exposed across the full face of the piston and dampened prior to the fluid continuing along the flow path.

Abstract: A screw rotor machine which incorporates a sound silencing device in the vicinity of the inlet and/or outlet port. The sound silencing device comprises a De Laval nozzle (8) having a valve body (9) which is movable axially in relation to the nozzle. When the machine is shut-down, the valve body (9) lies sealingly against the opening (8A) of the nozzle. When increasing the capacity of the machine to full load, the valve body (9) moves in the opening direction under the influence of a damping force and against the action of a substantially constant spring force (14), so as to maintain a flow rate immediately beneath the sound of speed in the smallest area (8A) of the nozzle (8).

Abstract: An air supply and exhaust control system for an internal combustion engine comprises at least first and second turbosuperchargers, an operation prohibiting portion for prohibiting the second turbosupercharger from working as occasion demands, an exhaust gas flow detecting portion, an air supply control portion for causing the operation prohibiting portion to prohibit the second turbosupercharger from working when a detection output from the exhaust gas flow detecting portion indicates that the exhaust gas flow is less than a first predetermined value, an exhaust gas discharging device connected to an exhaust passage in possession of variable exhaust resistance for discharging the exhaust gas, an exhaust resistance changing portion for changing the variable exhaust resistance, and an exhaust control portion for controlling the exhaust resistance changing portion to set the variable exhaust resistance to be relatively small when the detection output from the exhaust gas flow detecting portion indicates that the

Abstract: A charge air system for an internal combustion engine includes a compressor wheel which is rotated to draw ambient air into a housing, compress the air, and to force the air through a discharge conduit into the the intake manifold of an internal combustion engine. The silencers may be placed in the inlet conduit or the outlet conduit to attenuate pressure fluctuations in the conduits, which are a source of significant noise.

Abstract: An improved patient support structure comprising an articulatable frame, a plurality of elongated inflatable sacks, some of the sacks having one or two comfort slots therein, a low pressure compressed air blower and a plurality of pipes and manifolds for carrying gas from the blower to the sacks. The sacks are connected to the gas supply pipes and manifolds so as to be easily detachable therefrom. Each manifold has a variable muffler to control gas exhaust. An automatic switching circuit determines whether to power the brushless DC electric motor from a rectified AC power source or DC power supplied by batteries carried unobtrusively by the support structure. A multi-outlet, variable flow, gas valve connects to the blower to the pipes and comprises a housing defining at least two cylinder chambers and a discrete outlet for each cylinder chamber. A primary silencer is connected to each discrete outlet. The sacks rest atop a neoprene membrane which covers a planar upper surface of the frame.

Abstract: The invention relates to an exhaust silencer device for an internal combustion engine, for placement in the exhaust pipe of the engine. The device according to the invention comprises a damper plate disposed in the exhaust pipe and pivotably about a shaft substantially perpendicular to the longitudinal axis of the exhaust pipe between a closed position, in which the damper plate covers the major portion of the exhaust pipe flow area, and an open position, in which it permits substantially free flow through the exhaust pipe. An operating device is arranged to actuate the damper plate to adjust its position dependent on the exhaust flow through the exhaust pipe.

Abstract: An exhaust control system for use in an internal combustion engine for controlling the flow of exhaust gases discharged from the engine to the atmosphere. The apparatus determines a first condition representing the engine speed being higher than a predetermined value, a second condition representing the transmission being not in neutral, and a third condition representing the throttle valve being not at or near its closed position. A control circuit generates a command signal only upon simultaneous occurrence of the first, second and third conditions. The apparatus includes a device responsive to the command signal from the control circuit for increasing the effective area of the exhaust passage.

Abstract: A control valve includes a valve body with a fluid inlet and a fluid outlet. A valve seat is mounted within the valve body between the inlet and outlet. A valve plug is reciprocally mounted within the valve body to engage the valve seat. A plurality of valve cages are removably mounted on the valve seat and surround the valve plug. The valve cages are mounted to define axial flow galleries. One of the valve cages includes a plurality of apertures and fins that extend radially into a gallery between the first cage and a second cage. The second valve cage is adjacent to and surrounds the first valve cage. The second valve cage includes a plurality of apertures and fins that extend into the gallery area between the second cage and a third cage. The third cage surrounds and is adjacent the second cage. A plurality of apertures are defined in an upper portion of the third cage member.

Abstract: An engine exhaust accessory unit comprises a tubular housing adapted to be fitted over the end of an exhaust header. The outer end of the tubular housing is partially obstructed by a pivotable rigid perforated plate. The plate is pivotally mounted about a transverse axis offset below the central longitudinal axis of the housing. The larger upper section of the plate causes it to swing outward in response to passage of exhaust gases through the housing. The perforated plate automatically modifies engine noises and varies exhaust back pressure as a function of its angular position about the transverse axis. A yieldable spring biases the plate to a perpendicular position across the housing, and resists pivotal movement of the butterfly plate in response to passage of exhaust gases. Stops in the path of movement of the plate limit its movement between a perpendicular position across the housing and a position parallel to the longitudinal central housing axis.

Abstract: A rotational mechanism to be disposed midway in a fluid passage may be utilized in a silencer, rotary pump, or the like. The mechanism is essentially provided with a casing defining a spherical chamber, a pair of shafts respectively having axes passing through the center of the interior space of the casing and crossing each other in a plane substantially perpendicular to the flow direction of the fluid, and a pair of impellers having at least two flat plate vanes and at least two bent vanes alternately positioned to the flat plate vanes. The impellers are related to each other such that one flat plate vane is abutted on one bent vane of the other impeller so that every two vanes can constantly partition the spherical space to be able to diminish the noise of the flow or to transport the fluid as a rotary pump with one impeller being driven and the other impeller being idly rotated, by making isolated spaces of different volume for creating the force of pushing away the fluid.

Abstract: Noise reduction mechanism for an engine, especially effective during idling nd operation at low RPM, is disclosed. Under those conditions, engine exhaust noise often represents a predominant part of the total vehicle noise. The noise reducing mechanism comprises a flow-throttling element that substantially closes the main exhaust passage when the engine is in the low-speed range; the exhaust gas and noise is forced to flow through a more effective muffling device to reduce the noise at the exit end of the system. At high engine speeds, the throttling mechanism is deflected to a maximum flow condition for avoidance of undesired back pressure in the exhaust system.

Abstract: Silencers for gas discharge devices employing easily replaceable cartridges utilizing juxtapositioned layers of wire mesh and porous absorbed material which dissipate exhaust noises of an exhaust system and deflect under pressure of the exhaust gases to provide a self cleaning function.

Abstract: A damper assembly comprising, in combination, a generally rectangular frame including side, top and bottom members, a plurality of damper blades supported at opposite ends on the side members of the frame for limited rotative movement about axes extending longitudinally and substantially centrally of the blades, each of said blades comprising a resilient sealing strip along at least one edge of said blade, and the ends of the blades being angled in opposite directions above and below the rotative axis of the blades, and cooperating with resilient side sealing strips in the frame, the ends of the blades wedging against the sealing strips as the blades approach closed position, the blades being held in closed position by the wedging action.

Abstract: An exhaust device is provided comprising a first diverging portion extending into a cylindrical envelope into which is axially displaceably mounted a streamlined conically shaped member adapted to be moved in relationship to the engine rating.