Abstract: An exhaust gas muffler comprises a double-walled casing having an inlet end receiving a stream of the exhaust gas and an outlet end for the exhaust gas, the outlet end comprising an outer tube surrounding a perforated inner tube spaced therefrom, and the tubes defining therebetween a perforation resonator chamber succeeded by a whistling sound resonator. The casing includes an outer wall and a corrugated inner wall defining a gap with the outer wall. A heat-resistant and sound-damping intermediate layer is arranged in the gap between the inner and outer walls and braces the inner wall against the outer wall. Transverse partitions divide the casing into a plurality of chambers between the inlet and outlet ends, and tubes connect the chambers and reverse the exhaust gas stream at least twice between the inlet and outlet ends.

Abstract: An intake muffler, which is particularly intended for use in two-stroke-cycle internal combustion engines, comprises a stiff housing, in which a partition defines two chambers. An inlet tube extends into the larger first chambr. At least two communicating tubes extend through the partiton. The second chamber communicates with a tubular outlet port. In order to ensure an effective damping of sound even in conjunction with a high engine power, the inlet tube consists of a diffuser, which is divided into two or more passages, and the tubes through which the two chambers communicate with each other differ in diameter and/or in length.

Abstract: A pulsation damper is disclosed for use in a standard air-conditioning compressor for an automobile. The pulsation damper consists of a body portion and a cap portion and the cap portion has an outer diameter that is dimensioned to be press fit within the outlet opening of the housing of the air compressor. Thus, the pulsation damper can be retro-fit in a standard air compressor housing and will not increase the overall size of the housing or require modification in the connecting tubing. The body of the pulsation damper consists of longitudinal groove-like passages which direct the fluid flow from one of two internal compressor discharge lines to a point where it opposes and is intermixed with the fluid flow from another internal discharge line. This opposition and intermixing of the two fluid flow paths, which have pressure pulses which are out of synchronism with each other, tends to cancel or reduce such pulses.

Abstract: A silencer is provided for reducing noise from exhaust gases from an internal combustion engine. The silencer is of the type having an outer cylindrical cover and a coaxial inner cylindrical tube which define between them an annular cylindrical chamber into which the exhaust gases which enter the silencer are admitted. The inner tube is a perforated tube, a first open end of which forms the sole admission orifice for the gases into the silencer and the other opposite end of which is closed. The inside wall of the outer cover is lined with a layer of absorbent material mounted about the inner tube along substantially the entire perforated length of the inner tube.

Abstract: The known muffler of an industrial engine, in which a channel communicating with an exhaust gas outlet is integrally formed on the inside of a muffler main body made of an aluminum diecast, and an inner lid is mounted to the open side of the channel to form an exhaust gas passageway serving also as a tail pipe, within the muffler main body as disclosed in Japanese Utility Model Application No. 63-127369 (1988) is improved. The improvements reside in that a cross-section area of the channel is reduced gradually or in a stepwise manner from its inlet towards the exhaust gas outlet so as to prevent carbon from adhering to the exhaust passageway, and in that at the exhaust gas outlet is formed a projecting wall adapted to butt against the inner lid, integrally with the muffler main body so as to prevent the exhaust gas escape without passing through the exhaust gas passageway.

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: 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: 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: 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: An in-line noise attenuation device for insertion into a gas induction system, such as the air induction system of an automotive vehicle internal combustion engine. The device comprises two plastic parts snap-fitted together. One part is an outer tube, and the other part, an insert disposed within the first part. The insert comprises a hollow ogival-shaped section that is axially coextensive with a frusto-conically shaped section of the outer tube to form an annular flow path of substantially constant cross section for the inducted air. The flow then passes through apertures in the insert to enter a venturi section. The flow continues through the venturi section and then exits the device. The venturi section serves to choke noise that propagates from the engine in the direction opposite the direction of airflow. The noise is reflected back to the engine by the hollow interior of the ogival-shaped section which is open toward the venturi section.

Abstract: A pulsation damper is disclosed for use in a standard air-conditioning compressor for an automobile. The pulsation damper consists of a body portion and a cap portion and the cap portion has an outer diameter that is dimensioned to be press fit within the outlet opening of the housing of the air compressor. Thus, the pulsation damper can be retro-fit in a standard air compressor housing and will not increase the overall size of the housing or require modification in the connecting tubing. The body of the pulsation damper consists of longitudinal groove-like passages which direct the fluid flow from one of two internal compressor discharge lines to a point where it opposes and is intermixed with the fluid flow from another internal discharge line. This opposition and intermixing of the two fluid flow paths, which have pressure pulses which are out of synchronism with each other, tends to cancel or reduce such pulses.

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 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 silencer (70) which is particularly adapted for use with a pneumatic grain conveyor (10) includes a housing (72) with an arrangement of internal baffles (78, 80 and 82) defining a serpentine flow path of increasing cross-sectional area between an inlet (74) and an outlet (76) which is self-cleaning and effects noise reduction without absorptive material that would otherwise quickly clog the silencer.

Abstract: In an automotive vehicle installed with a V-6 engine, engine revolution speed and engine load are detected and a selector valve provided in a silencer is normally closed but it is opened when the engine revolution speed exceeds a predetermined engine revolution speed value when the 3rd order component of exhaust sound coincides with a longitudinal resonance frequency within a vehicle cabin when the vehicle is at acceleration. The selector valve which is normally closed is opened when the engine revolution speed exceeds a second predetermined engine revolution speed value when the 1.5th order component of the exhaust sound coincides with the longitudinal resonance frequency.

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 kit includes a self-contained muffler which attaches to the output exhaust system of a small two-cycle engine, such as a model engine that is in the range of 0.15 to 1.25 cubic inches displacement. The kit provides a low cost adaptation of existing engine manifolds to meet required sound reduction guidelines of below 90 Db at nine feed from the engine. The kit is easily adapted and installed on a wide variety of manifold-muffler adaptations, for example model engines using a mounting bolt which clamps the kit muffler to a portion of the existing engine muffler.

Abstract: The invention is directed to a compact noise abatement muffler for an internal combustion engine. The muffler includes a housing having a plurality of chambers and fluid conductors for enabling the exhaust gases passing through the muffler to achieve at least 4 changes of direction of gas flow. The muffler of the invention is capable of reducing the sound pressure level of the exhaust gases between the input and exhaust ports of the muffler in the range of 10-25 decibels.

Abstract: A surge eliminator includes a longitudinal cylindrical housing (10) with rounded ends (12) and (14). Fluid flows into inlet chamber (20) and through pipes (34) to a first dampening chamber (22). The fluid then flows from the chamber (22) to a chamber (24) through pipes (36). Fluid then flows from chamber (24) to an outlet chamber (26) through orifices (38) to an outlet (18). The fluid is continually oriented such that it must turn 180.degree. from the inlet to the outlet in each of the dampening chambers.

Abstract: A compact, sound-attenuating muffler for an internal combustion engine is disclosed in which the muffler includes a stream dividing partition positioned proximate the inlet of the muffler to divide the incoming exhaust gases into two streams of substantially equal volume. The stream dividing partition directs the streams laterally of the inlet in directions diverging from each other, and the muffler sound-attenuating assembly further includes corridor defining partitions receiving the streams from the stream dividing partition and maintaining the streams in corridors as coherent substantially eddy-free streams. The corridor defining partitions further direct the streams laterally to converge towards each other for discharge of the coherent streams against each other from opposed directions in a common volume inside the muffler casing. Further sound attenuation is accomplished by a common channel receiving the streams after they are intersected or discharged against each other.

Abstract: An automotive muffler has sound attenuating means in the form of one or more frame subassemblies which are formed of two identical transverse partitions and two identical longitudinal partitions secured at opposite ends to the transverse partitions and acting with them and the muffler housing to provide a retroverted exhaust gas flow path.

Abstract: A retroverted flow type exhaust gas muffler has curved flow directing and guiding plates mounted on end headers to facilitate flow reversal.

Abstract: A muffler for use on an internal combustion engine includes an enclosure generally cylindrical and having end plates for closing the internal volume of the enclosure, at least one partition plate for dividing the internal volume of the enclosure into at least two chambers, an inlet tube, supported by one of said end plates and at least one partition plate, for conducting combustion gases supplied from the engine to one of the chambers; an outlet tube, supported by the other of the end plates and at least one partition plate, for blowing out the gases from remaining one of the chambers; and a connecting tube supported by said at least one partition plate for interconnecting the volume of adjacent ones of the chambers. At least two of the inlet, outlet and connecting tubes are integrally made of a single sheet of metal shaped to form a combination tube including the at least two tubes. A method of manufacturing such a combination tube is also provided.

Abstract: The muffler comprises a main sound arresting chamber formed in the interior of an outer cylinder of the muffler and a bracket fixedly secured to the outer surface of the outer cylinder for mounting the muffler on a body of a motorcycle. The muffler is provided with an auxiliary sound arresting chamber formed in the interior of the bracket and communicating with the main sound arresting chamber through a connecting passage so as to increase the total volume of the sound arresting chamber, thereby permitting the output of the engine of the motorcycle to be enhanced while the sound arresting effect on the exhaust gas is improved. The main sound arresting chamber may be divided into an upstream side main sound arresting chamber portion and downstream side main sound arresting chamber portions by partition means and the auxiliary sound arresting chamber portion communicates with the upstream main sound arresting chamber portion. The connecting passage may be in the form of a plurality of small diameter holes.

Abstract: Disclosed is a simple steam trap muffler. It is comprised of two comentric pipes which are both welded at their first ends to the exhaust pipe of a steam trap. The steam and condensate flows into the inner pipe from the exhaust pipe. The inner pipe has its opposite end capped so that the steam and condensate can not flow to the atmosphere through this inner pipe. However, the inner pipe does have orifices in its circumferential side through which this fluid can flow into the annular space between the first and second concentric pipes. There is no cap on the second end of the outer pipe. Thus the fluid flows along this annular space and out of the muffler through this open end of the outer pipe.

Abstract: A muffler for exhaust gases of an internal combustion engine. The muffler is a hybrid consisting of gas expansion chambers defined by partitions in a muffler casing, and a sound-absorbing body. The sound-absorbing body includes a perforated pipe surrounded by a porous sound-absorbing material with a thin metal film sandwiched therebetween.

Abstract: A catcher for use in liquid and abrasive-laden liquid jet cutting apparatus that includes a separate fluid-filled chamber for reducing noise. The catcher also provides for increasing the speed of return flow to reduce the length of fluid required to absorb the kinetic energy of a jet.

Abstract: The invention is a venturi of unusual configuration and a method and apparatus for forming such a venturi in a single operation from a rounded, deformable tube. According to the invention, diametrically opposing sides of the tube are inwardly deflected in increasing amounts from opposing ends of the tube so as to form along the length of the tube from either end a first chamber of increasingly flattened and reduced cross-section followed by a second chamber of decreasingly flattened and reduced cross-section. An elongated throat section of maximally flattened and reduced cross-section may be provided between the first and second chambers, particularly for engine muffler venturis. The tube is conveniently deformed by applying pressure to a pair of its opposing sides along at least a portion of its length, preferably by pairs of opposing dies or eccentric rollers. Venturis for engine mufflers are conveniently fabricated from thin walled steel tubes by cold forming the tubes in the manner described.

Abstract: Apparatus for removing particulate from gases. The apparatus includes an inlet conduit, an outlet conduit, and a cylindrical gas processing chamber positioned between and interconnecting the inlet conduit and outlet conduit. The processing chamber is also connected to a particulate collection chamber by a channel. The gas processing chamber includes a cylindrical wall. A hollow cone-shaped deflector member is positioned in and spaced away from the walls of the processing chamber and is positioned between the inlet and outlet conduits. Gases entering the apparatus flow through the inlet conduit and contact the deflector member. The deflector member directs the major portion of gases from the inlet conduit radially outwardly toward the wall of the gas processing chamber. The gases deflected radially outwardly travel around the deflector member and along the wall of the processing chamber.

Abstract: A muffler for use on an internal combustion engine includes an enclosure generally cylindrical and having end plates for closing the internal volume of the enclosure, at least one partition plate for dividing the internal volume of the enclosure into at least two chambers, an inlet tube, supported by one of said end plates and at least one partition plate, for conducting combustion gases supplied from the engine to one of the chambers; an outlet tube, supported by the other of the end plates and at least one partition plate, for blowing out the gases from remaining one of the chambers; and a connecting tube supported by said at least one partition plate for interconnecting the volume of adjacent ones of the chambers. At least two of the inlet, outlet and connecting tubes are integrally made of a single sheet of metal shaped to form a combination tube including the at least two tubes. A method of manufacturing such a combination tube is also provided.

Abstract: A universal muffler construction (10) comprising: a muffler housing member (11), housing end plate members (12), a primary exhaust tube array (13), a baffle locator plate element (15), an auxiliary exhaust tubing array (16), and, auxiliary end plate elements (17) which are orientable with respect to one another to produce a variety of different internal muffler flow path configurations.

Abstract: The present invention is directed to muffler apparatus and a method for making same. The apparatus includes inlet and outlet tubes with a plurality of baffles extending from the inlet and outlet tubes to a housing. The outlet tube has a constricted portion near its inlet end formed with creases and lobes and a flare at the end. Such constriction increases the housing to outlet tube area ratio of the muffler which results in advantageous attenuation characteristics. The process for making the muffler is simpler than known methods since the outlet tube is formed and baffles pressed onto it in a single step.

Abstract: A muffler is disclosed comprising a closed housing having an annular inlet and an annular outlet neck, and the housing having arranged therein a pair of axially extending pipes which are at least partially overlapping one another. One of the pipes is connected to the inlet neck and has a circumferentially arranged passageway to permit the exhaust gases to be directed from the inlet neck to the inside of the housing. The other pipe is connected to the outlet neck and has a circumferentially arranged passageway to permit the exhaust gases to be directed from inside the housing to the outlet neck.

Abstract: A muffler for exhaust gases of an internal combustion engine. The muffler is a hybrid consisting of gas expansion chambers defined by partitions in a muffler casing, and a sound-absorbing body. The sound-absorbing body includes a perforated pipe surrounded by a porous sound-absorbing material with a thin metal film sandwiched therebetween.

Abstract: A plug section for a muffler, including an outer body and having an inlet pipe for introducing exhaust gas into the body. The inner end of the inlet pipe located within the body portion is closed off. Surrounding the inlet pipe is a conical baffle having a small diameter end secured to the inlet pipe to provide a tapered chamber between the inlet pipe and the conical baffle, while the space between the conical baffle and the outer body defines an outer chamber. Both the inlet pipe and the conical baffle are provided with a plurality of perforations. Exhaust gas entering the inlet pipe flows outwardly through the perforations in the inlet pipe to the tapered inner chamber and then flows through the perforations in the conical baffle to the outer chamber. The use of the perforated conical baffle provides a substantial improvement in sound attenuation, reducing both the shell noise level and the outlet noise level.

Abstract: A muffler for an internal combustion engine for effectively damping noise over a wide frequency range, from low frequency noise to high frequency noise. An absorber packed type muffler adapted to absorb noise by a sound absorbing material is inserted in and fixed to a housing which has a bore or bores thereinside, thereby forming one of a pipe inserted type muffler, a resonance type muffler and an interference type muffler to attain combined characteristics of both the types of mufflers.

Abstract: A muffler connected to an exhaust system of an automotive or like internal combustion engine for damping noise, which accompanies engine exhaust, using a sound absorbing member. An intertwined meshwork in a tubular configuration serves as means for covering and firmly retaining the sound absorbing member, which is wound around a perforated pipe, on the outer periphery of the perforated pipe. The tubular meshwork is produced by intertwining in a desired density strings each of which is made up of a number of strands.

Abstract: A muffler for internal combustion engine houses a catalyst for exhaust gas purification and is provided with an exhaust gas inlet pipe through which exhaust gas from the engine is fed to the upstream side of the catalyst. The exhaust gas inlet pipe includes an inlet pipe section provided therein with a venturi section through which atmospheric air as secondary air is inducted into the exhaust gas inlet pipe. The inlet pipe section is extended in the direction of exhaust gas flow to form an extension pipe section which has a length of at least two times the inner diameter of the extension pipe section, thereby suppressing cutoff frequency at lower levels.

Abstract: An exhaust muffler comprises a closed chamber, an inlet pipe leading into the chamber, an outlet pipe leading from the chamber, two spaced bulkheads dividing the chamber into first and second buffer compartments separated by an intermediate compartment containing a glass fibre pack, three pass tubes extending through the bulkheads and across the intermediate compartment, two of the pass tubes forming continuations of the inlet and outlet pipes respectively and having flared open ends in the buffer compartments respectively, and a parabolic noise reflector located opposite the open end of said two pass tubes in such manner as to reflect down the pass tubes a proportion of the noise generated by gases flowing along the pass tubes.

Abstract: A muffler for use with various instruments and furnished with a spark arresting function. An inlet pipe for receiving exhaust gases from the instrument and an outlet pipe for discharging the exhaust gases to the atmosphere are arranged in an expansion chamber of a housing with their one end open to the latter. The expansion chamber is divided into two compartments by a partition having a wire net therewith. An intermediate pipe for providing fluid communication between the two compartments is mounted on the partition. The air flow area of the wire net and the cross-sectional area of the intermediate pipe are selected such that the quantity of the gases flowing through the wire net is larger than that of the gases flowing through the intermediate pipe. The outlet pipe is formed with an exhaust gas inlet through its side wall portion which is larger in area than the open one end and covered with a wire net.

Abstract: A muffler for dissipating the sound component in exhaust gases from an internal combustion engine or the like is disclosed which has an enhanced useful life. The muffler includes a partition positioned across an incoming stream of exhaust gases. The partition is formed with stream dividing or splitting means which positively divides the stream into portions that can be more evenly directed throughout the muffler. This prevents destructive preferential flow of gases within the muffler. Additionally, shielding of sound absorption material in the muffler is accomplished by selecting the pattern of perforations to reduce the contact of such material with high velocity gases.

Abstract: An exhaust muffler comprises a closed chamber, an inlet pipe leading into the chamber, an outlet pipe leading from the chamber, two spaced bulkheads dividing the chamber into first and second buffer compartments separated by an intermediate compartment containing a glass fiber pack, three pass tubes extending through the bulkheads and across the intermediate compartment, two of the pass tubes forming continuations of the inlet and outlet pipes respectively and having flared open ends in the buffer compartments respectively, and a parabolic noise reflector located opposite the open end of said two pass tubes in such manner as to reflect down the pass tubes a proportion of the noise generated by gases flowing along the pass tubes.

Abstract: The expansion chamber shell into which the gas from a noise source, such as an internal combustion engine, is rushed is held in an outer shell in a manner to define therebetween a clearance which acts as a sound damping means against the gas passing through the muffler. Thus, the noise caused by the inevitable vibration of the expansion chamber shell is prevented from being directly transmitted to the outside of the muffler.

Abstract: A draining device used in a car muffler includes a muffler body separated into three compartments A, B and C with water passing holes disposed to their bottoms, an inlet pipe communicated to the compartment B, two intermediary pipes used to communicate the exhaust gas between the compartments B and C, and C and A, an outlet pipe communicating with the compartment A which is disposed at the front side of the muffler, and a water drain path having inlet port opened to the bottom of the front side compartment A and outlet port opened to the surrounding portion of the outlet pipe.

Abstract: An exhaust assembly for a tractor having a pivotal or slidable engine hood that must be moved out of the way to permit an operator complete access into the engine compartment. The exhaust assembly includes a tubular housing positioned within the engine compartment below the top surface of the engine hood. The tubular housing has a cylindrically shaped inlet conduit adapted to be connected to the exhaust manifold of the tractor engine. Exhaust gases are forced vertically into the inlet conduit and then directed in a horizontal swirling fashion through the tubular housing by apertures and baffles along the length of the inlet conduit. The tubular housing further includes a cylindrically shaped outlet conduit having an open conical discharge end which is in close proximity to the lower end of an elongated exhaust tube that is attached to the engine hood.

Abstract: At least one of the ends of the silencer an end chamber is defined between an intermediate planar dished wall and an end dished wall which is provided with a rounded and hollow boss. The boss substantially extends two exhaust gas tubes in front of which it is located and its apex is spaced from the intermediate dished wall by a distance which is slightly greater than the radius of the tubes so that the boss guides the change in direction of the gas flow between the tubes.

Abstract: A muffler for a portable engine for a chain saw or the like including separable dish shaped members having mating peripheral edges which, when interfitted one within the other, form a hollow shell. Exhaust gas inlet and outlet openings are formed in an end wall of one of the members and a deflector member is mounted exterior of the shell and is adapted to redirect the flow of exhaust gas leaving the muffler outlet openings so that the exhaust gas flows generally in the same direction as engine cooling air flow over the engine and the muffler. A shield is mounted on the shell and has a major portion spaced from the muffler shell to form a cooling air flow passage. The separable shell members, deflector, shield and a tubular diffuser disposed within the shell are held in assembled relationship on the engine by removable threaded fasteners.