Abstract: This invention relates to a muffler and in particular to one including a high frequency chamber, a first exhaust pipe connected between an engine and the high frequency chamber, a second exhaust pipe disposed within said high frequency, an intermediate frequency chamber connected with the other end of the second exhaust chamber, a third exhaust pipe disposed within the intermediate frequency chamber, a low frequency chamber connected with the other end of the third exhaust pipe, and a tubular pipe disposed within the low frequency chamber, whereby the noise will be effectively suppressed without decreasing the flow rate of the exhaust gas and the output power of the engine.

Abstract: The invention relates to a rigidifying structure used to support half shells of a stamp-formed muffler by connecting at least one of the half shells to an inner plate disposed in the space between the half shells so that shell noise is minimized.

Abstract: Muffler assembly for an engine comprises an outer cylinder constituting a muffler body, an inner cylinder coaxially disposed in the outer cylinder, a connection cylinder disposed inside the inner cylinder having one end on an upstream side and another end on a downstream side, a partition plate disposed inside the inner cylinder at the downstream end of the connection cylinder, first and second silencer chambers formed at the upstream and the downstream end of the connection cylinder, respectively, an inlet, pipe through which an engine exhaust gas is introduced into the muffler body, and an outlet pipe having an upstream end disposed inside the inner cylinder and a downstream end opened outward of the muffler assembly. The connection cylinder has an upstream end portion in which a plurality of holes are circumferentially formed.

Abstract: A muffler for muffling engine operating sounds and including a cylindrical shell closed at opposite ends by double-walled closure caps. The space within the shell is partitioned into three axially contiguous chambers. A gas charging pipe projects through one end of the shell and axially within the shell, and has two pairs of facing discharge elbows for discharging gas from the charging pipe at locations in the first of the chambers. A first pair of gas transfer pipes extends from the first chamber into the central chamber to points of opposed gas discharge. A second pair of gas transfer pipes extends from the central chamber into the third or discharge chamber, and from this location, the gas passes out of the muffler via a discharge pipe.

Abstract: This invention relates to sound attenuating mufflers, and more particularly to sound attenuating mufflers for dampening sound waves of various frequencies above a pre-selected cut-off frequency. Specially positioned acoustical insulation is provided to partially attenuate sound waves of a relatively low frequency. The insulation is carried in a chamber having one dimension of sound wave travel on the order of one-tenth the wavelength of a preselected cutoff frequency above which sound attenuation is desired. An adjacent chamber substantially free of insulation has one dimension of sound wave travel on the order of one-quarter wavelength of the cutoff frequency.

Abstract: An improved muffler for silencing the exhaust emitted from a water cooled marine engine comprising a housing enclosure partitioned by an angularly disposed inner planar baffle, the housing having an inlet for the exhaust gas and cooling water to fluidly communicate with a lower silencing chamber wherein the exhaust gas and cooling water are forced through a central passageway into an upper silencing chamber resulting in flow reversal and diminution in flow velocity so as to attenuate the exhaust noise, the exhaust gas and cooling water exiting the upper silencing chamber through an outlet fluidly communicated therewith and disposed collinearly with the input. The upper silencing chamber acting as a back flow preventor.

Abstract: A muffler assembly of an internal combustion engine comprises an inner casing in which is defined a first expansion chamber into which is inserted one end of the exhaust pipe having another end connected to an exhaust gas port of the engine, an outer casing disposed outside the inner casing so as to define second and third expansion chambers between the inner and outer casings, a first baffle pipe disposed so as to mutually communicate the first and second expansion chambers, a second baffle pipe disposed so as to mutually communicate the second and third expansion chambers, and a tail pipe member disposed so as to communicate the third expansion chamber and the outside of the outer casing. The inner and outer casings are formed by two plate members, respectively, which are secured together when the muffler assembly is assembled. A sound absorption chamber is formed around the outer periphery of the tail pipe.

Abstract: An adjustable sound attenuating device comprised of an elongated outer main shell of a predetermined diameter, with an inlet coupling and an outlet coupling. The device has located within the shell singular or multiple independent baffle components comprised of a solid baffle plate, a perforated baffle plate, an optional perforated baffle plug, and several chambers provided by the baffle components. The solid and perforated baffle plates have a funnel shape to provide for smooth directional flow of exhaust gases. The perforated baffle plate is pierced with a plurality of openings to allow for the flow of the exhaust gases through the chambers. The perforated baffle tube is pierced with inwardly angled louvers spaced equally around the circumference and staggered to follow a spiral path lengthwise around the perimeter of the tube for routing gases through the chambers.

Abstract: A fractional horsepower single cylinder refrigeration compressor utilizes a discharge muffler system having a discharge plenum and a pair of muffler chambers. The muffler chambers and interconnected by a transfer tube while separate passages run from the discharge plenum directly to each of the muffler chambers. One of the muffler chambers is then connected to a discharge line to the exterior of the compressor case.

Abstract: A reinforced stamped muffler is provided. The muffler includes a pair of internal plates secured in face-to-face relationship and formed to define an array of tubes and chambers therebetween. The chambers are provided with at least one array of reinforcing grooves. Larger chambers defined by the internal plates may include a first array of parallel reinforcing grooves and a second array of parallel reinforcing grooves extending transverse to and intersecting the end-most grooves in the first array. All of the grooves preferably extend into intersection with planar portions of the internal plates. The muffler further includes external shells formed to define larger chambers. The larger chambers of the external shells are formed with a major pattern of reinforcing undulations and a minor pattern of undulations or grooves superimposed thereon. The minor pattern preferably includes a parallel array of grooves with end most grooves in the parallel array being intersected by orthogonally extending grooves.

Abstract: A muffler for reducing noise associated with exhaust systems includes an assembly of exhaust tubes and drop-in baffles fixed inside channels defined in a clamshell-type muffler chamber formed from two stamp-formed mating external shells.

Abstract: An automobile for racing comprises a body, an engine, wheels, a fuel system, an exhaust system and wings having an adjustable angle of attack arranged so as to provide an upwardly directed force in the rear part of the automobile for racing and to create a turning moment relative to the front wheel axle in order to increase the maximum speed during racing by reducing friction of the automobile. Wings are arranged so as to create a turning moment relative to the front wheel axle and to lift the automobile or to provide aerodynamic braking by a remote control system. The wings are adapted to provide maneuvering of the automobile by aerodynamic braking separately of each wing. A fuel system of the automobile comprises a device for energizing the air-fuel mixture adapted to reduce the consumption of fuel. The automobile for racing comprises a tire inflation detection system adapted to inform an occupant of the automobile when the inflation pressure of any tire is reduced.

Abstract: A compact, sound-attenuating muffler for an internal combustion engine or the like. The muffler has a divergently tapered partition located near the inlet of the muffler for dividing the exhaust gases into two pulse streams with similar sound frequencies to achieve sound attenuation when the streams are converged back together. The diverging partition creates a low-pressure volume or region on the partition's downstream side where unignited fuels may accumulate. The partition is formed with a passageway to provide communication of live fire from the inlet of the muffler to the low-pressure volume for ignition of any unignited fuel. A method of communication of live fire from the inlet of the muffler to the low-pressure volume on the downstream side of the diverging partition in the muffler also is described.

Abstract: The invention provides a marine propulsion device comprising a powerhead including an exhaust gas discharge port, a gearcase rotatably supporting a propeller shaft connected to the powerhead and including an exhaust gas discharge, and a lower unit including an upper portion supporting the powerhead and a lower portion connected to the gearcase, with the lower unit comprising an inner exhaust housing having a generally vertical wall, an open top in communication with the powerhead exhaust gas discharge port, a bottom having therein a first exhaust gas outlet and a second exhaust gas outlet at the top portion of the wall, and an outer exhaust housing also having a generally vertical wall in surrounding relation to the inner exhaust gas housing and defining a vertically extending generally annular space between the inner and outer exhaust gas housings, the space communicating with the second exhaust gas outlet.

Abstract: A muffler for muffling engine operating sound and including a double-walled cylindrical shell closed at opposite ends by double-walled closure caps. The space between the shell walls is filled with sound-absorbing solid particles. The shell is partitioned into three axially contiguous chambers. A gas charging pipe projects through one closure cap and axially within the shell, and has two pairs of facing discharge elbows for discharging gas from the charging pipe at locations in the first chamber. A first pair of gas transfer pipes extends from the first chamber into the central chamber to points of opposed gas discharge. A second pair of gas transfer pipes extends from the central chamber into the third or discharge chamber, and from this location, the gas passes out of the muffler via a discharge pipe.

Abstract: In order to accomplish the aforementioned and other objects, a resin muffler, according to the invention, is formed of a heat-resistantive synthetic resin having a property of visco-elastic plasticity in a predetermined temperature range. In the visco-elastic temperature range, the motion of the molecular chain segment of the material resin comes to be relaxed to exhibit noise creative pulsating energy dissipation owing to emission as heat energy. Since the resin muffler thus absorbs noise creative energy by dissipation at around the visco-elastic temperature range and transform the energy into the heat energy which may be emitted by radiation.

Abstract: An exhaust processor is provided for filtering particulate matter from a combustion product. The exhaust processor includes a housing providing a main passageway having a substrate mounted therein for solid particle filtration. The housing also provides an auxiliary passageway containing a muffler for attenuating noise of combustion product. Combustion product is diverted through the auxiliary passageway after the substrate collects a predetermined amount of solid particles from combustion product to permit regeneration of the substrate by a burner.

Abstract: A sootblower wallbox assembly for decreasing noise emissions during the cleaning of a heat exchanger apparatus. In particular, the invention relates to a wallbox assembly containing a number of reverberant chambers exhibiting varying attenuation characteristics. When a cleaning lance is extended centrally through the wallbox assembly, a baffle portion of each chamber is in close fit relation with the exterior surface of the lance. Each reverberant chamber has a different axial length and therefore exhibits a different frequency range where it achieves its best sound attenuation. The wallbox assembly can also be provided with control systems to prevent combustion products from escaping the heat exchanger through the assembly.

Abstract: An engine exhaust including a silencer which has a cylindrical shell, a front and a rear end plate which are provided to close both ends of the cylindrical shell, and at least three partition walls to divide an inside space of the silencer into a plurality of chambers, i.e. at least a first chamber, a second chamber, a third chamber and a fourth chamber. An inlet pipe which bypasses at least the first and the second chambers, and connects the front end and the third chamber. The inlet pipe has a plurality of small holes which face toward the first and the second chambers. The small holes facing the second chamber are surrounded by a sound absorber. An outlet pipe bypasses at least the second, the third and the fourth chambers and connects the first chamber and the rear end plate. The outlet pipe has a plurality of small holes which face toward the third and the fourth chambers. The small holes facing the fourth chamber are surrounded by a sound absorber.

Abstract: An acoustic filter in which the internal flow element is acoustically decoupled from the surrounding vessel to lower noise emanating from the filter by securing the filter bulkheads to the internal flow element rather than welding to the vessel wall. The connection of the bulkhead to the vessel is mechanically discontinuous and reduced vibration transmission to the vessel from the internal flow element is obtained. The internal flow element is a unitary body with channels which are readily formed. The filter vessel is better able to move relative to the bulkheads in response to pressure and temperature changes with the invention design.

Abstract: An engine exhaust apparatus in which an exhaust passageway of the engine is provided with a plurality of sound deadening passsages. One common exhaust passageway from the engine is branched into first and second exhaust passageways. Each of the first and second exhaust passageways has a silencer or muffler including first and second exhaust outlet tubes with a shift valve mounted in one of these exhaust outlet tubes. A control unit controls the shift valves to close both when engine speed is in a low region, to open one of them when engine speed is in a medium region and to open both when engine speed is in a high region.

Abstract: A muffler is constructed to have a tubular perforated plate within its cavity so as to divide the cavity into an outer resonant cavity and an inner resonant cavity, to thereby provide two resonant frequencies. The tubular perforated plate is formed in the shape of a funnel.

Abstract: A muffler is provided with a pair of plates formed to define an array of tubes therebetween. At least one external shell is secured to at least one of the plates to surround selected portions of the tubes. The shell is formed to define a plurality of chambers separated from one another by a baffle crease. The baffle crease is parallel to and abutting a selected tube of the muffler to simplify the draw of metal material in the vicinity of the baffle crease and to thereby save metal. The baffle crease is of substantially uniform depth along a major portion of its length and is free of pockets that could conceivably retain corrosive fluids.

Abstract: A sealed case has first and second housing portions. A motor section is arranged in the first housing portion of the sealed case and has a rotating shaft extending toward the second housing portion. A compression section has first and second compression mechanisms stacked in the second housing portion of the sealed case and driven by the rotating shaft. A first valve cover has a predetermined volume so as to temporarily store a high-pressure fluid discharged from the first compression mechanism near the motor section. A second valve cover has a predetermined volume larger than that of the first valve cover so as to temporarily store a high-pressure fluid discharged from the second compression mechanism opposite to the motor section.

Abstract: An air compressor comprises an air-compressing section and a pulsation-absorbing tank which are arranged isolated from each other, a nozzle, provided for one of the compressing section and the pulsation-absorbing tank, for supplying compressed air from the compressing section into the pulsation-absorbing tank, and a flexible nozzle seal provided for the other one of the compressing section and the pulsation-absorbing tank and having a hole in the center thereof. One end of the nozzle is inserted in the hole of the nozzle seal. With the nozzle inserted in the hole of the nozzle seal, the nozzle seal is applied with the pressure of the air contained in either the air compressing section or the pulsation-absorbing tank and is thus brought into light contact with the outer periphery of the nozzle.

Abstract: An improved muffler of relatively large size for internal combustion engines is shown, which comprises a main hollow shell, assembled from half sections with caulked flanges to join the sections together into an airtight enclosure, at least one perforated baffle plate having its periphery clamped between the opposite edges, exhaust inlet and outlet ports. The baffle plate is bent into a curve defining in the inside of the shell chambers differing in volume from one another, through which the exhaust gases from an engine are forced to flow so that the gases alternately expand and contract. In addition to the rigid integration of the baffle plate with the shell by caulking, various interlocking and elastic members rigidly interconnect between the plate and the inside walls of the shell in such a manner as to reduce development or transmission of the vibrations in the shell components due to the pressure oscillations of the exhaust gases.

Abstract: A muffler for an internal combustion engine comprises: a communicating passage constituting member allowing a plurality of chambers formed by partitioning walls inside an outer shell to be communicated with each other; and a butterfly-type valve provided in the communicating passage. The communicating passage constituting member is formed into the shape of a gutter so as to face either an inner surface of the outer shell at an open side of the constituting member or an outer surface of the outer shell at an open side of the constituting member. Alternatively, the communicating passage constituting member is constituted by a pipe and is provided in the outer shell. The arrangement makes it possible to improve the engine output, reduce the back pressure, and enhance the sound-damping effect.

Abstract: A muffler assembly includes an inner outlet tube having a tubular portion, a frusto-conical portion and a flange portion having an expanded orifice facing the outlet of an inlet tube. Both the outlet tube and inlet tube extend within a chamber defined in an outer housing. The chamber is divided into two or more subchambers by a baffle which extends between the outlet tube and the housing. One or more holes in the baffle improve the sound attenuation characteristics of the muffler. The invention also comprehends a novel blank used in forming the outlet tube, and three alternative methods which may be used to form the outlet tube.

Abstract: A stamp formed muffler includes upper and lower internal plates and upper and lower external shells secured to the respective internal plates. The internal plates are formed to include arrays of channels that are placed in register with one another to define an array of tubes. The external shells are formed to define chambers that surround selected tubes formed by the internal plates. The upper internal plate includes at least one pair of aligned channels disposed in spaced apart end-to-end relationship and in register with a continuous channel in the lower internal plate. The chambers of the external shells are separated from one another by baffle creases. The baffle crease of the upper external shell is disposed in registration with the spaced apart aligned channels of the upper external shell. As a result, the baffle crease of the upper external shell is substantially free of pockets that conceivably could trap foreign materials.

Abstract: This invention provides an improved method and apparatus for attenuating the sound of flowing fluid. The apparatus of this invention includes at least two attenuating areas, preferably particle-filled containers arranged serially within a housing. One of the attenuating areas has a central void into which a portion of the fluid may flow on its way through the muffler. The muffler may also include a mechanism for permitting one of the attenuating devices to move in order to accommodate changes in fluid pressure.

Abstract: An automotive exhaust gas muffler comprises gas passage tubes supported in curved portions of two press-formed metal housing parts and communicate with recesses formed in the housing parts.

Abstract: Muffler apparatus including an elongated muffler which is connectable to an engine body via two exhaust pipes. The muffler includes a first expansion chamber which extends along the entire length of the muffler, and the two exhaust pipes are connected separately adjacent opposite ends, or in the vicinity of the ends, of the muffler on the side of the muffler at which the first expansion chamber is located.

Abstract: A regenerable desiccant cartridge for an automotive muffler including a tubular wire mesh sleeve containing adsorbent and having opposite end portions, an elongated metal base plate extending the entire distance of the sleeve and having end portions crimped over the open ends of the sleeve, the base plate also including rounded corners.

Abstract: A muffler assembly includes a pair of outer shells mating to define a muffler chamber and a pair of internal tuning plates mating to define inlet and outlet tubes in the muffler chamber. Drop-in baffles are used to divide the muffler chamber into an expansion chamber, a pair of exhaust turnaround chambers, and a pair of resonance chambers. The two outer shells and first tuning plates are mechanically locked together at the perimeter of the muffler assembly and the second tuning plate is piggybacked onto the first tuning plate to reduce the number of material layers included in the mechanical lock. Each of the outer shells includes one or more ribs and channels for stiffening the outer shell to reduce vibration noise and to conduct condensate developing in the muffler chamber either to a hotter region where it will vaporize or to a drain.

Abstract: An improved design for the central power and suction unit of built-in vacuum cleaning systems, which improved design provides significant acoustic damping to substantially reduce the noise level generated from the central power and suction unit. The design further permits the canister of the central power and suction unit to rest on the floor. The motors of the central power unit are enclosed within an interior chamber which includes at its lower end a baffle supporting an acoustic damper such as acoustic foam and the interior chamber is vented through exhaust ports the tips of the armatures are separated from the remainder of the armatures and motors by the baffle and the tips of the armatures extend into another chamber which further includes a second acoustic damper within the chamber and further includes openings for permitting cooling air to enter the chamber. Through this design, the noise level generated from the motors is very substantially reduced while the motors are sufficiently cooled.

Abstract: A tubular sock made of fibrous material is placed over a louver patch formed in an exhaust flow tube mounted in a muffler to attenuate engine exhaust noise. A slip tube is provided for preventing the tubular sock from becoming entangled on the louver patch as it is being placed on the exhaust flow tube.

Abstract: A muffler is provided comprising an array of tubes and a stamp formed external shell surrounding the tubes. The external shell is stamp formed to define at least one chamber surrounding at least portions of the tubes. The chamber extends away from peripheral portions of the external shell to define a three-dimensional volume. The chamber is characterized by a plurality of inwardly directed V-shaped grooves, with each groove extending continuously between opposed spaced apart locations on the periphery of each chamber. The grooves preferably define a parallel array of substantially identical grooves. The grooves strengthen the walls of the chamber and efficiently prevent shell noise.

Abstract: A muffler has a muffler body within which is located an intermediate duct pipe colinear with the exhaust and tail pipes, so that exhaust gas from the exhaust duct pipe can pass through a main flow route in the intermediate duct pipe in a substantially straight line without reflecting. An inner or by-pass pipe forms a gas by-pass and has gas flow restriction elements.

Abstract: A gas silencing system for controlled sound attenuation of the exhaust gas in a motor vehicle comprises a sound attenuation muffler for exhaust gases. The system also includes means providing a bypass passage for gas to flow around at least part of the muffler. Bypass control valve is provided to allow selective regulation of the flow of exhaust through the muffler and the pass-pipe. The bypass control valve is responsive to a modulated pressure signal controlled by the driver of the vehicle. The invention also includes circuits for visually indicating the amount of bypass flow and the sound level of gas leaving the system.

Abstract: A muffler includes a first expansion chamber, a second expansion chamber, a resonator chamber and an inlet pipe having a first open end and a second open end. The first open end of the inlet pipe is inserted into the first expansion chamber so as to communicate with the first expansion chamber. A resonator pipe runs substantially in coaxial relationship with the inlet pipe so as to establish communication between the first expansion chamber and the resonant chamber. A return pipe is disposed between the resonator chamber and the second expansion chamber and passes through the first expansion chamber for establishing communication between the first expansion chamber and the second expansion chamber. An outlet pipe communicates with the second expansion chamber. Said return pipe is inserted with the open end into said resonator chamber, while the inserted open end of the return pipe is furnished with a plug. A portion of the return pipe passes through the first expansion chamber.

Abstract: An exhaust tube capable of having a better silencing effect without adversely affecting the horsepower output of an engine is provided. The exhaust tube includes a tube body having two end plates, two spaced disks dividing the tube body into three gas chambers and a pipe having an expanded first end, a first horizontal portion, an inclined portion having a verturi tube, a perforated second horizontal portion, and a second opposite free end.

Abstract: A stamp formed exhaust muffler for mounting on a vehicle is provided. The muffler comprises a plurality of plates secured in juxtaposed relationship and stamp formed to define an array of tubes therebetween. At least one external shell is secured to the internal plates to define at least one chamber which communicates with the array of tubes. The external shell includes at least one conformal area which permits the muffler to conform to the shape of a structure on the vehicle. The conformal area may be an area of generally arcuate concavity when viewed from the exterior of the muffler or may define an internal corner on the muffler. Thus, a plane or line connecting two locations on the conformal area of the external shell will pass through the interference zone of a structure on the vehicle. The conformal area may be disposed where peripheral edges of the formed components are joined.

Abstract: The invention provides a pressure-fluctuation and noise suppressor having low flow resistance and high effectiveness. It is especially useful as a suppressor for an oil-injection inlet system of a positive-displacement air compressor. It has a cylinderical housing separated into ante- and main chambers by a partition. A tubular suppressing element is fixed through the partition eccentrically of the axis of the housing. The inlet of the suppressing element is in the form of a nozzle in the ante-chamber that widens away from the partition. In the main chamber, the wall of the suppressing element is perforated and the end of the suppressing element in the main chamber is closed by a conical member. An outlet tube is situated on a side wall of the housing in a plane perpendicular to the axis of the housing on an axis transecting the axes of the chambers and the suppressing element. An inlet extends into the ante-chamber diagonally from the nozzle of the suppressing element.

Abstract: A light weight exhaust muffler is provided comprising a pair of formed external shells and a pair of pipes disposed therein. The external shells are formed to include peripheral portions and chambers extending from the peripheral portions. The chambers are separated from one another by baffle creases unitary with the respective external shells. Portions of the baffle creases of one external shell are secured in face-to-face contact with corresponding portions of the baffle creases in the other external shell. The baffle creases comprise arcuate portions corresponding to the shape of the pipes passing between the chambers separated by the baffle creases.

Abstract: A light weight exhaust muffler is provided comprising a pair of formed external shells and a pair of pipes disposed therein. The external shells are formed to include peripheral portions and chambers extending from the peripheral portions. The chambers are separated from one another by baffle creases unitary with the respective external shells. Portions of the baffle creases of one external shell are secured in face-to-face contact with corresponding portions of the baffle creases in the other external shell. The baffle creases comprise arcuate portions corresponding to the shape of the pipes passing between the chambers separated by the baffle creases.

Abstract: A system of stamp formed mufflers is provided. Each muffler in the system includes a pair of plates formed to define an array of tubes therebetween. At least one external shell is securely affixed to at least one of the plates to surround the tube. The mufflers in the system have generally the same pattern of tubes therein. However selected mufflers in the system have portions which are different from other mufflers in the system depending upon the acoustical requirements of the particular muffler in the system.

Abstract: Two embodiments of improved exhaust gas systems for outboard motors. In each system, the slow speed exhaust gases go through at least three expansions and contractions before discharge to the atmosphere. In one embodiment of the invention, the slow speed exhaust gases go through four expansions and contractions. In each embodiment of the invention, one of the expansion chambers has communication with another expansion chamber through a neck that is tuned whereby the neck and the one expansion chamber function as a Helmholtz resonator for tuning intermediate and high speed exhaust gas discharge.

Abstract: The invention is directed to an exhaust gas muffler for a two-cycle engine, especially for a handheld portable tool, such as a chain saw. In exhaust gas mufflers equipped with a catalyzer, the formation of flame from the fuel-containing exhaust gases exiting from the muffler must be prevented. These exhaust gases are intensely overheated because of the exothermal process in the catalyzer. The muffler according to the invention includes a catalyzer which establishes a connection between separate component chambers of the muffler housing. The muffler can be mounted directly on the motor outlet.

Abstract: A muffler for impeding and reflecting exhaust to reduce the formation of sound waves through a plurality of cone and barrier assemblies alternately and longitudinally spaced in a cylindrical body, with the apex of a conical member of each cone assembly and an outwardly extending cylindrical portion of each barrier assembly being directed towards the input end of the body. Exhaust flow paths for dissipating exhaust noise are defined by orifices formed in the conical members and cylindrical portions, and spaces between spokes joining each conical member to a circular member.

Abstract: A muffler is provided with a pair of stamp formed internal plates and a pair of stamp formed external shells. The internal plates define inlet and outlet tubes at least portions of which are provided with arrays of perforations or louvers. One or more tuning tubes may be stamp formed in the internal plates and one or more low frequency resonator chambers may be stamp formed from portions of either the internal plates or the external shells. The external shells may further be configured to define high frequency tuning chambers of a selected size and shape.