Abstract: An improved exhaust emission control device is disposed in a motor bicycle of the type in which a muffler body, containing a catalyst for exhaust emission control, is connected to an exhaust pipe extending from the exhaust port of the associated engine, and the exhaust pipe is inserted into the muffler body through the front section thereof and extends through the inner space of the muffler body to the rear section thereof. The exhaust pipe is turned back in U-shape at the rear section to the front section of the inner space of the muffler body and the catalyst, supported by a partition wall which is disposed in the muffler body, is positioned in the vicinity of the opening of the exhaust pipe.

Abstract: A muffler for use on the exhaust system of the motor vehicle. The muffler has a central pipe which is surrounded by an outer pipe which leaves an annular space between the two. The outer pipe is open at both ends and the annular space is filled with a sound deadening material. The central pipe has openings which pass to the annular space and a perforated sound deadening member is affixed to the inner surface of the central pipe. Preferably, the outer pipe is outwardly flared at its upstream end, and the perforated sound deadening member is conical in shape.

Abstract: A resonator type silencer installed in an intake system of an automotive internal combustion engine. The resonator type silencer comprises a generally cup-shaped base member integrally connected with an air duct through which intake air to be inducted into the engine passes. The air duct is formed with an opening through which the inside of the base member is in communication with the inside of the air duct. The base member is formed at its opened end with a peripheral flange. A cover member is formed at its opened end with a peripheral flange which is bonded to the peripheral flange of the base member to define a sealed chamber. A partition plate is fixedly disposed inside the sealed chamber to divide the sealed chamber into a first resonance chamber defined by the base member, and a second resonance chamber defined by the cover member.

Abstract: A vertical exhaust system for an internal combustion engine that incorporates a provision for receiving and trapping water, such as rain, that may enter the open upper end of the exhaust conduit. The exhaust system includes a vertical outer body and a perforated tube is disposed within the outer body and spaced therefrom to provide an annular chamber therebetween. A plug or closure is secured within the tube and is spaced from the lower end of the tube, thus closing off the tube. An annular flange interconnects the inner tube with the outer body and is spaced longitudinally below the plug, to thereby enclose the lower end of the chamber. A drain hole extends through the outer body and connects the chamber with the exterior. The drain hole is spaced above the flange, so that the space between the flange and the drain hole comprises a trap to collect water that may enter the upper end of the exhaust system.

Abstract: A spark arrester is mounted in a tail pipe of an exhaust pipe of an engine, in particular a 2-strokecycle engine, and prevents sparks from being emitted. The spark arrester includes a sack-like member of a wire mesh and a cylindrical member secured to open end of the sack-like member. The cylindrical member received in the tail pipe is retained therein by a resilient retainer in a groove formed in the inner peripheral wall of the tail pipe.

Abstract: An improved muffler for silencing the exhaust emitted from a water cooled marine engine employing a first housing encompassing a second housing which is partitioned by an angularly disposed inner planar baffle further having an inlet for exhaust gas and cooling water to fluidly communicate into an inlet chamber of the second housing resulting in a diminution in flow velocity so as to attenuate the exhaust noise, the exhaust gas and cooling water exiting the inlet chamber through an aperture fluidly communicated therewith into a silencing volume formed by an area between the first and second housing and forced through an aperture into an outlet chamber of said second housing. The outlet chamber acting as a back flow preventor.

Abstract: A means and method of design and installation of a pre-rotator ahead of an elbow are disclosed in order to eliminate or reduce elbow-induced turbulence in pipe flows. Experimental verification was conducted, and noise and pressure loss for flow around the elbow can be substantially reduced.

Abstract: A resonance detection device is provided for detecting resonance in an exhaust passage of an automotive vehicle. The detection device employs a temperature sensor in combination with an arrangement which enables the sensor to be exposed to a flow of exhaust gas the temperature of which is different from the temperature of the bulk of the flow, when resonance occurs. In given embodiments the arrangement takes the form different diameter conduits and/or vessels, while others it takes the form of a heat exchange device which either heats or cools the gases, and which is disposed proximate the temperature sensor. When no resonance occurs in the passage, the output of the temperature sensor remains stable. When resonance occurs the fluid flow characteristics in the passage change in a manner wherein the gas which has been either heated or cooled by the heat exchange device is induced to flow against the temperature sensor.

Abstract: A vertical exhaust pipe having an inner pipe with an upper opening. An outer pipe is positioned around the inner pipe and has an end portion that extends beyond the upper opening in the inner pipe, said end portion defining an outlet through which exhaust gas exits the outer pipe. A mechanism is coupled with the inner pipe for blocking rain that has entered the outer pipe from falling through the opening in the inner pipe. A ledge mechanism is positioned beneath the upper opening in the inner pipe and between the inner and outer pipes for forming a chamber within which is held rainwater that has entered the outer pipe. A drainage mechanism allows rainwater in the chamber to pass to the exterior of the outer pipe.

Abstract: An exhaust silencer has an inner, flexible pipe having a plurality of connected overlapping annular sections, an outer casing and a noise-suppressing material between the pipe and the outer casing. The casing has a first strip wound helically in a first direction of winding with partial overlap in a first overlap region between adjacent portions of the strips. A curable adhesive is arranged between the adjacent portions in the overlap region to provide a substantially leak proof seal.

Abstract: A refrigeration compressor incorporating an improved suction muffler is disclosed. The suction muffler provides dual sound attenuating chambers within a single housing, which housing is secured to the suction inlet conduit extending between the motor cover and suction inlet for the compressor. Integrally formed openings in the sidewall of the conduit provide communication with each of the two chambers and the respective chambers may be tuned to attenuate different specific frequencies. Internal integrally formed baffles within each of the chambers serve to eliminate standing waves within the chambers as well as adding stiffness to the muffler.

Abstract: A sound attenuating device is provided for attenuating noise in an exhaust system. The attenuating device includes an inlet end, an outlet end and a constricted portion therebetween. In use, the attenuating device may be disposed in a tubular housing or may be an integral portion of a tail pipe, connecting pipe, or muffler. Further, a sound suppressing system is described including one or more attenuating regions including attenuating devices. The attenuating regions are spaced to attenuate desired frequencies. Expansion chambers formed between attenuating regions contribute to sound suppression.

Abstract: A silencer device is installed into the discharge pipe of a centrifugal compressor by first installing a channel shaped frame in the discharge pipe and then sliding the silencer device into the frame to be contained for operational use. The orientation and placement of the frame and its contained silencer device is parallel with the direction of flow to thereby reduce the resulting pressure drop, and it is placed near a turn in the discharge pipe such that the sound will tend to be reflected from the discharge pipe to cause multiple passes through the silencer device and thereby enhance its absorptive performance. The absorptive material within the silencer device is protected from erosion by a surrounding cloth bag composed of a fine weave Nomex material.

Abstract: An exhaust duct part for the outflow of a fluid, in particular for the outflow of the exhaust gases of an internal combustion engine, includes a continuous external casing of substantially constant cross-section and containing at least one acoustic attenuation unit positioned longitudinally in the external casing so as to delimit at least one fluid transfer section of a length determined in such a way that the transfer section participates in the acoustic attenuation function of the exhaust duct part. The attenuation unit includes an internal casing of substantially constant cross-section and, together with the external casing, delimits at least one longitudinal peripheral channel for the passage of the fluid. The internal casing has a circular or elliptical cross-section and includes at least one zone deformed radially in such a way as to increase the surface of exchange between the fluid and the attenuation unit.

Abstract: A muffler device for reducing the noise level of an internal combustion engine as exhaust gases and sound waves produced by the operation of the engine are expelled into the atmosphere is disclosed. The device is placed in the exhaust system, being disposed within the exhaust pipe or pipes as close to the exhaust manifold as possible. The device has a sound chamber for attenuating sound waves entering the chamber by deflection of the sound waves back toward their source and a venturi for drawing exhaust gases through the device and expelling them to the atmosphere.

Abstract: An exhaust muffler for use with an internal combustion engine has at least one internal suppression chamber, at least one inlet pipe for receiving exhaust gases from the internal combustion engine, and at least one outlet pipe vented to atmosphere. The exhaust muffler comprises a plurailty of component units connected in series with each other and each having the internal suppression chamber. Each of the component units has a casing having an inner layer of a sound-absorbing material which defines the internal suppression chamber, and a connector pipe connected to and extending through the casing, the connector pipe having upstream and downstream ends projecting out of the casing, the connector pipe having at least one opening which opens into the internal suppression chamber.

Abstract: A tuned, convoluted, stainless steel conduit assembly is especially well adapted for use in hostile environments subject to vibrations which bring on fatigue failures. To prevent the conduit from having a uniform resonance throughout its length, the convolutions have a variable wall thickness. One way this variable wall thickness may be achieved is by forming the conduit walls by wrapping stainless steel tape in successive layers to form a multiple layered wall. The width of the tape may be such that some convolutions have more layers than other neighboring convolutions. A stainless steel sleeve or stocking loosely fits over the conduit and is clamped by one or more tuning bands onto the conduit to prevent vibration of the conduit at that clamped location.

Abstract: A tuned convoluted conduit assembly is especially well adapted for use in hostile environments subject to vibrations which bring on fatigue failures. To prevent the conduit from having a uniform resonance throughout its length, the convolutions have a variable wall thickness. One way this variable wall thickness may be achieved is by forming the conduit walls by wrapping tape in successive layers to form a multiple layered wall. The width of the tape may be such that each alternate convolution has more layers than its two adjacent neighboring convolutions. A sleeve or stocking loosely fits over the conduit and is clamped by a band onto the conduit to prevent vibration of the conduit at that clamped location.

Abstract: A tube of a muffler for an internal combustion engine includes at least two generally rectangular sheets which are joined together at one end by crimping and wound in a tubular configuration to constitute two consecutive layers. In the tubular configuration, the other end of each of the two sheets overlaps the sheet itself and welded to the latter straddling a coupling portion where the two sheets are joined. While one of the sheets which constitutes an inner layer of the tube is made of a material which is resistive to corrosion due to chemical reactions with combustion gas and others flowing through the tube, the other which constitutes an outer wall of the same is made of a material which withstands adverse ambient conditions such as briny air and high humidity.

Abstract: A convoluted conduit is especially well adapted for use in hostile environments subject to vibrations which bring on fatigue failures. To prevent the conduit from having a uniform resonance throughout its length, the convolutions have a variable wall thickness. One way this variable wall thickness may be achieved is by forming the conduit walls by wrapping tape in successive layers to form a multiple layered wall. The width of the tape may be such that each alternate convolution has more layers than its two adjacent neighboring convolutions. Another way of making the conduit is to provide a plurality of coaxially nesting tubes which cooperate to form a wall thickness. Brazing or packing material may be positioned between adjacent layers of tape to seal the conduit and to make the wall behave at that point as a single layer.

Abstract: A tail pipe for drafting an engine exhaust gas includes: a front perforated pipe connected to an engine exhaust silencer or muffler, an outer pipe jacketed outside the front pipe for leading environmental air therein, a central pipe connected on a rear end portion of the front pipe and disposed inside the outer pipe, and plural swirl perforated plates each helically secured between the central pipe and the outer pipe and each swirl plate securing the rear portion of the front pipe between the outer pipe and the central pipe, whereby upon a discharge of an engine exhaust gas, the pressure of a partial exhaust gas stream is reduced by the induced environmental cooling air and the pressure of the remaining gas stream is further reduced since the gas stream is guided through the swirl perforated plates to exert an eddy flow at the pipe exit to strongly suck the exhaust gas outwardly.

Abstract: An exhaust plenum chamber for a supercharged engine having a variable volume. A mechanical spring is arranged to an exhaust plenum chamber to increase the spring action of the plenum chamber volume. In this connection, the plenum chamber interior is divided into a flow chamber and a dead volume. The efficiency especially of relatively small plenum chambers in internal combustion engines with a small number of cylinders and/or slight supercharging is improved.

Abstract: An air intake noise suppressor for reducing noise generated by intake air sucked into an internal combustion engine. An intake pipe is provided with a resonance pipe, which extends forwards within the intake pipe as penetrating through a rear end wall of the intake pipe, communicates with the interior of the intake pipe through an opening at its front end, extends backwards from the rear end wall externally of the intake pipe and has its rear end closed, and the resonance pipe is fixedly locked to the intake pipe at its portion penetrating through the rear end wall and in the proximity of the opening at the front end. Since the resonance pipe is accommodated within the intake pipe over a considerable length and only its rear end portion projects backwards from the intake pipe, a surplus space is almost not necessitated for mounting the resonance pipe, and yet the resonance pipe itself can be made sufficiently long.

Abstract: An exhaust silencing device comprises an outer tube that is pinched down to form a series of annular chambers around a coaxial inner gas flow tube and has openings connecting the chambers to provide for some secondary gas flow parallel to primary flow through the tube. The device and is shown in conjunction with a catalytic converter to provide an exhaust system that has a sporty sound.

Abstract: It has an inlet and an outlet, a bag made from a flexible, deformable material insulating the inlet from the outlet, a liquid contained in the bag on the outlet side, a transfer tube with openings on its side wall and closed by an end plug. Diffusers are positioned on the transfer tube with a given spacing, so as to leave a passage for a gas between two successive diffusers, each diffuser comprising a frame externally surrounded by an elastomer ring.

Abstract: An exhaust tail pipe of an engine is covered at its end section with an outer cover member leaving therebetween a space communicated with ambient air. Many perforations are formed in the tail pipe end section to allow the inside of the tail pipe end section to communicate with the space. Each perforation has a diameter d (mm) within a range expressed by the following formula: ##EQU1## where A(l)=the displacement of the engine; D(mm)=the inner diameter of the exhaust tail pipe end section; and C=the kind of stroke cycle of the engine, thereby allowing a part of exhaust gas flowing through the tail pipe end section to dissipate to the space through the perforations.

Abstract: A flexible means is interposed between a first exhaust conduit fixed to the power unit of an automobile and a second conduit elastically supported by the automobile body, and conveys the exhaust gases of the power unit from the first exhaust conduit to the second exhaust conduit. The flexible means has a first end portion fixed to the first exhaust conduit and a second end portion fixed to the second exhaust conduit. The flexible means further has a middle portion which is a bellows which extends between and is bounded by the first and second end portions to form an expansion chamber therebetween. The chamber is fluidly connected with the first exhaust conduit and the second exhaust conduit.

Abstract: An exhaust duct connector takes the form of a Y-shaped passage. Both of the branches of the Y are adapted to receive ends of upstream exhaust ducts and a leg of the Y is adapted to receive one end of a downstream exhaust duct. A substantially plate-like partition is positioned at the junction of the Y parallel to the single leg. The partition includes a plurality of holes through which exhaust can pass. The partition may include an outer partition member having a plurality of holes and an inner partition having numerous extremely small holes covered by the outer partition member. The partition may contact the adjacent inside wall of the Y-shaped passage, or be spaced from the adjacent inside wall of the Y-shaped passage. The partition may take the form of an airfoil.

Abstract: A tuneable exhaust pipe for an internal combustion engine having a baffle slidable longitudinally within the exhaust pipe at the upstream end a plug in the downstream end. The baffle and plug each have an opening for passage of exhaust gasses therethrough. The baffle defines a resonate chamber on each side of it. The chambers avoid turbulence and maintain the shock wave in the gasses so that the chambers cause an additive dynamic relationship calculated to cause a supercharging effect on the engine by increasing the internal pressures therein.

Abstract: An improved exhaust system (24) uses the entire length of the system in which to perform the essential functions of muffling noise and converting unburned hydrocarbons. The improved exhaust system (24) performs these functions with a relatively uniform minimum diameter along its length. The exhaust system (24) includes a uniform outer diameter pipe (26) and elements (44) of porous material (46) forming a plurality of filters (50) through which the exhaust gas flows and which attenuates sonic frequency sound waves in the exhaust. The elements (44) are preferably elongate strips which may be folded into rectangular filters (60) or elliptical filters (90). The rectangular filters can be folded sufficiently to form squares and the elliptical filters to form circles. The rectangular filters define passageways (62-68) between the edges of the filters and inner wall (70) of the pipe (26) which further attenuates exhaust noise through imbalances in the gas flow.

Abstract: Whereas the total noise level of an internal combustion engine supercharged by means of a gas-dynamic pressure-wave engine (1) (PWS) is usually only slightly higher than that of an engine supercharged by means of an exhaust-gas turbo supercharger (ETS), the narrow-band noise in the PWS rotational sound frequency range, the so-called PWS "whistle", is considered troublesome. The absorption muffler (3) is an elongate body, the length (l.sub.1) of which is at least 10 times the rotor outside diameter of the PWS. The inside diameter (d) of the muffler (3) corresponds to the inside diameter of the exhaust pipe (4) and is at least 0.6 times the rotor outside diameter of the PWS. The thickness (S) of the insulating material, which directly surrounds the inside diameter (d) or inner cross-section (F) of the muffler (3), is at least 6 times the rotor outside diameter of the PWS divided by the number of cells of the PWS.

Abstract: An exhaust system for motor vehicles comprising a plurality of exhaust pipes and silencers connected thereto, the silencers being disposed above a rear wheel and at least partially inside a rear cowling. A dynamic effect of the exhaust pipes against the exhaust of an engine is suppressed to an appropriate extent while attaining a favorable external appearance.

Abstract: A corrugated tube consists of a one-piece metallic basic body with corrugations arranged concentrically about the tube axis and one behind the other, which corrugations each have an annular space in the radial zone between the corrugation trough and the corrugation apex. This annular space is closed at its interior by means of two mutually concentric annular wall parts which are seated on one another and are relatively slideable one within the other in the axial direction. On the axial side remote from the associated corrugation the annular wall parts adjoin a radial annular space which is opened towards the tube interior and dimensioned as narrowly as possible as regards its radial and axial width.

Abstract: In order to reduce static and dynamic pressures in pipelines or tubes and, in particular, in order to attenuate the transmission of sound through tubes in a longitudinal direction it is proposed to provide an outer member and/or an inner member of the tube in such a way as to afford elastic yieldability. Such an elastically yieldable outer member may, for example, be constituted by a low-wave, soft, radially breathing compensator or a corrugated tube. An elastically yieldable inner member may, for example, be constituted by an imperforate breathing body disposed within the tube.

Abstract: From the exhaust tube of automobiles the power source sounds and travelling sounds are radiated as noises. A heat-resistant intermediate layer is disposed partly around the inner tube of dual metal tubing and achieves decreases in the radiated noise from the exhaust pipe due to the vibration damping of the inner and outer tubes.

Abstract: A muffler and exhaust extractor especially adapted for internal combustion engine powered vehicles such as over the road diesel tractors. The muffler and exhaust extractor generally stated comprises a pair of spaced curved airfoils for directing the airstream produced by the moving vehicle through an open ended converging-diverging passage to form a low pressure area for gas extraction, and means for mounting the airfoils such that the low pressure area is adjacent to and in communication with the exhaust outlet of the vehicle.

Abstract: A chambered-core motorcycle-exhaust apparatus having an inner exhaust core system comprising a plurality of interconnected pipe segments, including a muffler-end segment, wherein the inner core is mounted within a tubular housing having a substantially larger diameter than the inner core, so as to establish an annular chamber between the outer housing and the inner exhaust core, to prevent substantial heat transfer to the outer housing and to reduce noise output normally associated with motorcycle exhaust systems.

Abstract: The noise of an exhaust gas flow of an internal combustion engine or other hermodynamic equipment is reduced by silators which are operatively arranged for deadening or absorbing the exhaust noise. Such silators have vaulted surfaces enclosing an evacuated volume which may include a cooling liquid. The silators have a resonance frequency that depends on the vaulting height and the free span or diameter of the vaulted surface. By properly dimensioning the silators and combining a plurality thereof each having a different resonance frequency, a wide frequency range of exhaust noises may be covered. Preferably the silator impedance is smaller than the air impedance of the environment. The silators are protected against the heat of the exhaust gases.

Abstract: An exhaust system for an internal combustion engine which comprises an exhaust manifold connected to said engine, a communication pipe connected at one end to the exhaust manifold, a bellows type exhaust tube connected at one end to the other end of the communication pipe, a second communication pipe connected at one end to the other end of the exhaust tube, a muffler connected at one end to the other end of the second communication pipe and a tail pipe connected at one end to the other end of the muffler. The exhaust tube comprises a multi-layered bellows, a cylindrical wire blade, or wire mesh shield, in outwardly radial spaced relationship to the bellows, the opposed ends of the cylindrical wire mesh shield having a reduced diameter, and retainer rings securing the opposed ends of the wire mesh shield to the communication pipes.

Abstract: An engine-transmission assembly wherein the engine in it is connected to a rear transmission unit by a supporting pipe which serves to reduce vibration and noise. According to preferred embodiments of the invention, the supporting pipe includes at least one outer pipe and an inner pipe fitted therein which are interconnected at only ends and are held in position via a friction seat. The pipes forming the supporting pipe can be of equal length and thickness or can be of varying length and/or thicknesses according to other embodiments.

Abstract: The invention provides an airflow control mechanism for use in an air duct for controlling airflow through the duct. The air flow control mechanism includes a frame positionable in the duct, and a plurality of blades supported by the frame and extending transversely to the direction of the air flow through the air duct. At least one of the blades is supported for pivotal movement about its longitudinal axis and has an elongated edge moveable toward and away from an elongated edge of another of the blades to restrict air flow through the duct. A fiber material strip is applied to at least one of those edges, the fiber material strip including a substrate bonded to that edge and a plurality of closely spaced fibers projecting transversely from the substrate, the fiber covering being functional to prevent the generation of a high frequency standing wave between the adjacent surfaces of the blade.

Abstract: A sound-attenuating muffler for reducing the acoustic energy in an exhaust gas stream has an elongated cylindrical housing with a small ratio of diameter to length. Axially extending vanes are radially disposed to define an added number of flow passages. Exhaust gas enters an entry passage defined between two vanes, travels past a side-branch resonator and terminates in the entry nozzle of a Helmholtz chamber. The flow turns through a port in one of the vanes and enters a reverse-flow passage, also defined between two vanes, flows past a side-branch resonator and is reversed again through a port through another vane. A third side-branch resonator is provided in the exit region. The muffler may comprise two or more separate similar muffler sections defining such serpentine gas flow paths, and the exit region of an upstream section may then be continuous with the entry region of a downstream section.

Abstract: A connecting line or exhaust pipe for disposal within the exhaust system of a motor vehicle driven by an internal-combustion engine between the exhaust manifold of the engine and the muffler. The connecting line is formed of two bowl-shaped sheet metal half-shells which are preshaped, e.g., by pressing, deep drawing or the like, and which are superposed on one another, and firmly connected together. The half-shells of the connecting line have a shape such that the connecting line has a non-circular substantially flat cross section with respect to its vertical dimension when the connecting line is connected in the vehicle exhaust system.

Abstract: Acoustical insulation or sound absorbing material particularly useful as automobile muffler material, having high temperature, vibration and chemical resistance, and of sufficient structural rigidity to resist packing or degradation when exposed to engine heat, vibration and exhaust gas pressures, formed of an alumina-silica ceramic fiber matt or blanket impregnated with a colloidal silica binder. The muffler acoustical and thermal insulation can be in the form of a hollow cylindrical body of alumina-silica fibers coated on its inside and outside surfaces and on its ends, with an aqueous colloidal silica sol, and the material dried.