Abstract: A compressor assembly having a tank seal which seals a tank gap between a portion of a housing of the compressor assembly and a portion of a compressed gas tank and a method for controlling the sound level of a compressor assembly by configuring a tank seal to seal a gap between the housing of a compressor assembly and a compressed gas tank. The sound level of the compressor assembly can be controlled by sealing a tank gap between at least a portion of a compressor assembly housing and at least a portion of a compressed gas tank.

Abstract: A water drainage assembly for an aftertreatment system comprises a first tube structured to be coupled to an outlet conduit of the aftertreatment system and has a first cross-sectional width. A second tube is disposed radially around the first tube. A first end of the second tube is coupled to a radially outer surface of the first tube. A portion of the second tube has a second cross-sectional width larger than the first cross-sectional width such that a volume is defined between the first and second tubes. A drain port is defined in the second tube proximate to the first end. The assembly is structured such that water flowing into the water drainage assembly flows into the volume defined between the first tube and the second tube and is expelled therefrom via the drain port.

Abstract: An apparatus and method are provided for an air filter configured to be mounted onto an air inlet of an internal combustion engine. The air filter comprises a first end cap configured to couple with a base which is configured to support a conventional air filter and provide an interface between the conventional air filter and the air inlet. A filter medium which is relatively thicker than the conventional air filter is configured to remove particulate matter and other contaminates from an incoming airstream. A second end cap is configured to couple with a cover which is configured to fasten the conventional air filter and the base onto the air inlet, such that the incoming airstream is directed through the filter medium. The air filter is configured to be installed in place of the conventional air filter without necessitating alteration of the base and cover.

Abstract: The apparatus and systems are for removing contaminants from an exhaust stream. The process may involve passing at least a portion of an exhaust stream through a cooling component, which draws a cooling stream into the cooling component. The cooling stream interacts with the at least a portion of the exhaust stream to form a mixed stream. The resulting mixed stream is a lower temperature than the at least portion of the exhaust stream.

Abstract: A muffler includes a first chamber, a second chamber, an extender tube, a reverse flow tube, and a separation chamber. The first chamber is coupled to an exhaust inlet of the muffler. The extender tube is coupled to the first chamber and the second chamber. The exhaust gas flows from the first chamber to the second chamber through the extender tube in a first direction. The reverse flow tube coupled to the second chamber. The exhaust gas flows through the second chamber from the extender tube to the reverse flow tube in a second direction different than the first direction. The separation chamber that provides spatial separation between the first and second chamber.

Abstract: Provided is a compressor as a device which can solve a contradictory technical problem of installing an intake sound muffler while downsizing the device under a circumstance that installation of the intake sound muffler is indispensable to reduce intake noise of the compressor, and the compressor comprises: a first lid part provided with a small hole which forms an intake port of the compressor, the lid part constituting a portion of a cylindrical casing of the compressor; a cylindrical part; and a second lid part which forms a small chamber together with the first lid part, wherein the second lid part is provided with a suction nozzle for sucking air into the small chamber.

Abstract: A conditioning device complements a silencer with higher sound attenuation and also allows the silencer to better withstand abrasion of grit entrained exhaust air flow from decompressing an airblast pot. The device is configured to achieve four functions. First is to control and direct the exhaust air flow. Second is to absorb the impact of the entrained particles. Third is to diffuse and slow down the exhaust air velocity. Fourth is to direct and deflect the sound waves to the sound absorption surfaces located downstream.

Abstract: A number of variations may include a product comprising a dump-able filter comprising: a filter body; a filter assembly, wherein the filter assembly is seated in the filter body; and a filter cap, wherein the filter cap attaches to the filter body and encloses at least a portion of the filter assembly. In some embodiments the filter assembly may include a filter carrier that includes a pressure relief valve.

Abstract: An engine capable of reducing the content of hydrocarbon in exhaust gas is provided. When viewed parallel to cylinder center axes, tangential virtual lines extending from endpoints of curved port central axes along tangent lines of the endpoints pass intake valve ports, straight port central axes extending from the endpoints of the curved port central axes are further away from a partition wall than the tangential virtual lines, and intake air bent through curved ports passes straight ports and is sucked through the intake valve ports along the wall between the cylinders.

Abstract: A single support core for a filter media assembly. The single support core includes a single longitudinal tube extending between a first end and a second end. A plurality of orifices are defined in the tube, the orifices align circumferentially along the longitudinal length of the tube. A first plurality of portions defined between the first end and an intermediate annular ring joint and a second plurality of portions defined between the intermediate annular ring joint and the second end. The orifices in each of the first portions and second portions are equidistance circumferentially from each other defining rings. The rings are equidistant longitudinally from each other in each of the portions and the rings are longitudinally spaced differentially in the adjacent portions. The plurality of orifices direct fluid flow through the tube to yield a high flow velocity in predetermined areas along the length of the filter assembly.

Abstract: A system is provided that includes an exhaust system. The exhaust system includes a first and a second conduit configured to receive an exhaust from an engine having at least two cylinders and configured to operate at a range of less than 600 revolutions per minute. The exhaust system further includes a first chamber configured to receive the exhaust from the first and the second conduits, and a second chamber downstream of the first chamber and fluidly coupled to the first chamber by using a third conduit. The exhaust system additionally includes a third chamber downstream of the second chamber and fluidly coupled to the second chamber by using a fourth and a fifth conduit and an exhaust stack downstream of the third chamber and fluidly coupled to the third chamber.

Abstract: An exhaust muffler for a vehicle includes a muffler body coupled to an exhaust pipe and a tailpipe coupled to the muffler body. The muffler body has a plurality of expansion chambers, an exit communication pipe that discharges exhaust to the tailpipe from one of the plurality of expansion chambers positioned in a most downstream part of an exhaust flow path, and a spark arrester arranged in the exit communication pipe. An exhaust flow path narrowing portion is provided at an entrance portion of the exit communication pipe.

Abstract: A spark arrestor mounted on a muffler connected to an exhaust pipe of an engine includes a cylindrical portion including an opening that extends therethrough from the outside to the inside thereof, two cap members that respectively close first and second ends of the cylindrical portion, a mesh portion that covers the opening, and a tail pipe extending from the inside to the outside of the cylindrical portion through the cap member, wherein the exhaust flows outside the cylindrical portion in a first direction, and a channel where the exhaust flows in a second direction opposite to the first direction is provided inside the cylindrical portion.

Abstract: A spark arrestor mounted on a muffler connected to an exhaust pipe of an engine includes a cylindrical portion including an opening that extends therethrough from the outside to the inside thereof, two cap members that respectively close first and second ends of the cylindrical portion, a mesh portion that covers the opening, and a tail pipe extending from the inside to the outside of the cylindrical portion through the cap member, wherein the exhaust flows outside the cylindrical portion in a first direction, and a channel where the exhaust flows in a second direction opposite to the first direction is provided inside the cylindrical portion.

Abstract: A motor/pump assembly for a motor vehicle brake system including a pump and a motor driving the pump, the pump having opposite working diaphragms which are, in each case, mounted between a pump casing and a cover and thereby delimit a space and which can be moved by a crank drive, the space being assigned, in each case, an inlet duct with an inlet valve and an outlet duct with an outlet valve. The outlet ducts are arranged in the covers and in the pump casing such that air displaced out of the spaces is conducted into an inner space surrounding the crank drive of the pump casing and that an air outlet unit be provided, which allows a low-noise blow-out of the air from the inner space as a result of the deflection of the air.

Abstract: A double-walled exhaust system component having glass bubbles disposed between inner and outer pipes and method of making the same. The glass bubbles have a size distribution wherein, on a bulk volume basis, at least 90 percent of the glass bubbles have a size of less than 150 micrometers.

Abstract: A muffler includes a muffler body in which a muffler chamber is formed by a base, a cover, and a baffle accommodated in the muffler chamber and disposed in the vicinity of the exhaust gas entry port of the muffler body. A guide portion which changes flow of an exhaust gas that enters from the exhaust gas entry port is integrally provided to the baffle by cut-and-raise of a portion of the baffle.

Abstract: The present invention relates to an exhaust gas treatment unit for an exhaust system of a combustion engine, in particular of a motor vehicle, includes a housing, a plurality of exhaust gas treatment elements, which are arranged in the housing and through which a parallel flow is possible. The unit further includes an outlet nozzle, which penetrates a side face of the housing, and an outlet space disposed in the housing, whereby the outlet of at least one of the exhaust gas treatment elements opens into the outlet space. The rigidity and/or effectiveness of the exhaust gas treatment unit can be improved by means of a funnel body disposed in the outlet space, and comprising a funnel surface which is permeable to exhaust gas. The funnel body connects an outlet end of one of the exhaust gas treatment elements with the outlet nozzle.

Abstract: An adsorption unit for combustion gas of an internal combustion engine has an adsorption housing having a chamber section with an inner wall. An adsorption element disposed in the adsorption housing is made of a gas-permeable adsorption medium that is formed to a hollow body and encloses an interior of the adsorption element. The hollow body has opposed open ends. A main flow passage extends through the hollow body and the combustion gas flows in main flow direction through the hollow body. The adsorption element has an exterior circumferential side facing away from the interior and delimiting together with the inner wall of the chamber section a bypass chamber surrounding the absorption element outwardly. In the main flow direction, the bypass chamber has a downstream end that is closed off and an upstream end that has at least one bypass opening that communicates with the main flow passage.

Abstract: A muffler (1) for an exhaust system (2) of an internal combustion engine, especially of a motor vehicle, with a muffler housing (3), which encloses a housing interior space (5), and with at least one exhaust gas-carrying hollow body (4) with two half shells in a half shell construction. The hollow body is arranged in the housing interior space (5). The two half shells (14, 15) of the hollow body (4) are fastened to one another in the area of a separating plane (16). The assembly of the muffler (1) or of the hollow body (4) can be simplified if the two half shells (14, 15) are fastened to one another by fastening elements (17, 18), which are formed directly on the half shells (14, 15).

Abstract: A tube comprises a series of guides with each successive guide smaller than a next prior guide forms an effective funnel with a smaller end extending toward into a larger end of a next adjacent guide. The larger end of the next adjacent guide extends past the smaller end of that prior guide and loops back to taper into smooth connection to the outside of the smaller end of that prior guide therein creating a cavity in the guide. Gas passing rapidly past the cavities causes a Bernoulli effect that reduces pressure within the cavities. Because the mouth of the guides is large, a vortex is induced from a shearing interface between gases within the cavity and the main flow of gas moving down the tube. A less energetic layer of gas is created that buffers tube guides from main gas flow through the tube center.

Abstract: An exhaust gas muffler for an internal combustion engine, especially the engine of a manually-guided implement such as a power saw, a cut-off machine, or the like. The muffler has a housing having an inlet for exhaust gases and an outlet out of the housing. The housing has an outer wall over which the exhaust gases from the outlet flow. To achieve an adequate cooling of the exhaust gas muffler and the discharging exhaust gases, the exhaust gases out of the outlet draw in atmospheric air between the exhaust gases and the outer wall of the housing.

Abstract: A motorcycle includes a spark arrester having an increased surface area without any undue increase in the length of a silencer or the width of the motorcycle. The motorcycle includes a rear wheel and a silencer provided on a side of the rear wheel. The silencer includes an outer tube and a spark arrester which is tubular and is disposed inside the outer tube, the longitudinal axis of the spark arrester being oriented in a longitudinal direction of the outer tube. In a sectional plane which is perpendicular or substantially perpendicular to the longitudinal direction of the outer tube and the spark arrester, the outer tube has an outside dimension in a height direction greater than an outside dimension of the outer tube in a lateral direction, and the spark arrester has an outside dimension in the height direction greater than an outside dimension of the spark arrester in the lateral direction.

Abstract: A filter bank is provided. The filter bank includes a housing having a front face and a back face. Air flows along an air flow path from the front face to the back face. A filter layer is held in the housing. The filter layer is oriented between the front and back faces such that air flows through the filter layer before discharging from the back face. An attenuation layer is positioned within the housing to attenuate sound as the sound propagates between the front and back faces. The attenuation layer is oriented to extend along the air flow direction.

Abstract: A motorcycle includes a spark arrester having an increased surface area without any undue increase in the length of a silencer or the width of the motorcycle. The motorcycle includes a rear wheel and a silencer provided on a side of the rear wheel. The silencer includes an outer tube and a spark arrester which is tubular and is disposed inside the outer tube, the longitudinal axis of the spark arrester being oriented in a longitudinal direction of the outer tube. In a sectional plane which is perpendicular or substantially perpendicular to the longitudinal direction of the outer tube and the spark arrester, the outer tube has an outside dimension in a height direction greater than an outside dimension of the outer tube in a lateral direction, and the spark arrester has an outside dimension in the height direction greater than an outside dimension of the spark arrester in the lateral direction.

Abstract: A cyclone dust collector includes a cyclone body including a first cyclone chamber to centrifugally separate dust from drawn-in air for a first time, a plurality of second cyclone chambers to centrifugally separate dust from the drawn-in air for a second time, and a plurality of discharge ports to cause the drawn-in air to be discharged from the plurality of second cyclone chambers; an upper cover to cover an upper portion of the cyclone body, the upper cover having an inner wall facing the plurality of discharge ports; and a noise reduction part disposed between the plurality of discharge ports and the inner wall of the upper cover, to reduce noise generated inside the upper cover by the air discharged through the plurality of discharge ports. Therefore, it is possible to reduce noise generated inside the upper cover of the cyclone dust collector.

Abstract: A passive secondary air muffler for a small internal combustion engine. The secondary air muffler may include a venturi device and a catalytic converter. The venturi device may be in the form of a stamped sheet metal insert which, along with the outer muffler housing or shell, forms a secondary or auxiliary air intake device. The venturi device may also be formed from baffles separating an inlet chamber from an outlet chamber of the muffler. The secondary air intake device provides auxiliary or secondary air to the exhaust gas stream exiting the engine upstream of the catalytic converter to improve the efficiency of the catalytic converter. In an exemplary embodiment, the venturi device has a hemispherical cross-sectional shape or a circular cross-sectional shape taken along a plane substantially perpendicular to the direction of flow of the exhaust gas stream.

Abstract: A vacuum cleaner includes a fan motor generating air current, a main body receiving the fan motor, a wheel allowing the main body to smoothly move, a flexible connecting hose extending from the main body, an expandable extending tube connected to the connecting holes, a suction nozzle connected to an end of the extending tube to suck outer air, an inner sound absorption member disposed around the fan motor to absorb noise generated by the fan motor, a casing disposed around the inner sound absorption member to enclose the fan motor, the casing being provided with an air hole through which the air is exhausted in a side direction of the fan motor, and an outer sound absorption member disposed around the casing to absorb the noise generated by the fan motor.

Abstract: A muffler for an engine in oilfield applications has a tube with nozzles in its inlet section for spraying a mist of water from the well into the exhaust gases produced by the engine, so that a significant portion of the water is converted to water vapor and exits with the exhaust gases at the outlet of the tube. Vortex generators on the interior surface of the midsection of the tube create turbulence in the exhaust gases and water mist. A sump at the outlet section of the tube collects the remaining water and pollutants trapped by the water for subsequent disposal.

Abstract: A motor chain saw includes a housing with a housing wall, which has an opening for exhaust gases and a hood extending outside the housing through the opening, with a hood opening pointing to one side. Exhaust gases flowing from an interior of the housing in an exhaust jet (S) are guided to the outside through the opening. A fin is arranged on the opening and provides a silencer for exhaust gases directed towards a flow direction of the exhaust jet (S) escaping from the hood.

Abstract: A filter assembly for use with compressor assemblies such as oxygen concentrators, ventilators and other breathing apparatus including a compartmented housing member having at least one inlet opening, an outlet opening, a filter member, and an adjustment member associated with the at least one outlet opening for varying the size of the at least one outlet opening for adjusting the amount of ambient air entering the filter assembly.

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

Abstract: A system for separating contaminants from an air stream entering a sealed case through a vent fitting communicating to the interior cavity of the case includes a contaminant separator having a housing enclosing a chamber, an inlet and outlet communicating with the chamber, a baffle located in the chamber and producing a constricted fluid flow passageway between the inlet and the outlet.

Abstract: A filter includes a housing with multiple flow passages and filter elements, including at least first and second flow passages therethrough including respective first and second filter elements in parallel. Respective internal dividing walls separate flow passages and are provided with acoustic attenuators.

Abstract: A silencer with a casing and at least one inlet passage for leading gas into said casing, and at least one outlet opening for leading gas out of said casing, said silencer containing at least one acoustic chamber contained in the casing, at least one porous body inside said chamber, the porous body comprising a through-flow filter occupying at least part of the chamber, where said at least one porous body is designed to retain particles contained in the gas, at least one connecting passage for leading gas from each one of the at least one acoustic chamber to another of the at least one acoustic chamber or to an exterior environment or an exterior chamber, wherein at least part of at least one of said connecting passages extends along an outer surface of the porous body, so as to lead gas along a helical flow path.

Abstract: An exhaust deflector is attachable to a muffler. The exhaust deflector includes a housing having a flange that is attachable to the muffler, and an outer wall extending from the flange. The outer wall defines an aperture. A single piece mesh is in contact with the flange and cooperates with the housing to define a space. A low-density material is disposed within the space.

Abstract: An exhaust deflector is attachable to a muffler. The exhaust deflector includes a single-piece housing having a flange that defines an inlet aperture, an outlet wall that defines an outlet aperture, and an intermediate wall that interconnects the flange and the outlet wall. A mesh is in contact with the flange and is positioned to cover the inlet aperture. A perforated member is sandwiched between the mesh and the intermediate wall such that the perforated member and the intermediate wall cooperate to define a space. A low-density material is disposed within the space.

Abstract: A cyclonic separating apparatus for separating solid material from a fluid includes a separating chamber, an inlet communicating with the separating chamber for carrying the fluid with the solid matter entrained therein to the separating chamber, and an outlet for carrying the fluid away from the separating chamber after the solid material has been separated therefrom. The outlet is formed by a conduit communicating with the interior of the separating chamber and having a longitudinal axis. A plurality of grooves are formed in an interior surface of the conduit outlet and extend in the same direction as the longitudinal axis. The presence of the grooves in the outlet has the effect of reducing noise generated by the apparatus when in use and also improves pressure recovery.

Abstract: The exhaust gas purification device has a first chamber having an exhaust pipe inlet, an ambient air inlet, and an exhaust gas outlet. A Venturi is arranged within the chamber, having an inlet end communicating with an ambient air inlet, a throat, and an outlet end communicating with an exhaust gas outlet. The Venturi has an exhaust gas inlet between its inlet end and its outlet end, receiving exhaust gas from within the chamber, directed generally towards the outlet end of the Venturi, so that ambient air and exhaust air are mixed in passing through the Venturi to its exhaust gas outlet. A perforated pipe within the first chamber receives the exhaust gas, and the exhaust gas escapes there from via the perforations, into the chamber and thence to the Venturi. A second chamber, having a catalytic substrate assembly mounted therein, receives the mixed ambient air and exhaust air from the exhaust gas outlet of the Venturi, and has an exhaust pipe outlet.

Abstract: A power unit for an in-wall vacuum cleaning system has a first compartment which contains a motor for producing a vacuum at remote wand receptacles and a second compartment for separating and collecting the debris. An improved sound reducer is mounted in the motor compartment for reducing the sound level emitted by the motor and providing good cooling airflow for the motor. The sound reducer includes a disc-shaped base having a central opening for receiving a portion of the motor and a pair of partitions mounted on the base and forming a plurality of irregularly-shaped sound passages for breaking up the sound waves traveling therethrough. The base and partitions are formed of an acoustic foam which assist in absorbing the sound waves.

Abstract: An exhaust valve and a catalyst can be easily disposed of in a simple manner. The interior of a triangular muffler is partitioned into three expansion chambers. A manifold pipe is connected to the second, middle expansion chamber sideways from a lower portion thereof and is accommodated therein so as to face upward. A catalyst is accommodated in the interior of the manifold pipe. Exhaust gas flowing out from an open end of the manifold pipe expands into the second chamber. A short-circuiting aperture is formed in a second separator and is opened and closed with an exhaust valve installed within the third chamber. The exhaust valve is normally closed by a spring. When the exhaust pressure reaches a predetermined magnitude, the exhaust valve opens automatically, allowing the exhaust gas to flow out into the third chamber through the short-circuiting aperture, thereby controlling the exhaust pressure.

Abstract: An exhaust gas muffler is provided for an internal combustion engine, especially for an internal combustion engine in a manually-guided implement such as a power saw, a cut-off machine, or the like. The muffler has a housing having an inlet for exhaust gases and an outlet out of the housing. To achieve an after burning of exhaust gas in a straightforward manner, the exhaust gases in the housing flow through a reaction zone in which the exhaust gases circulate at least partially.

Abstract: A suction apparatus is provided with noise reduction means in one or more airflow passages for reducing noise emission from an airflow generator or the like, wherein at least one airflow passage is provided with at least one indentation with a predetermined depth extending substantially perpendicularly to the general direction of the noise in the passage.

Abstract: A muffler having a muffler body divided into first and second exhaust chambers by a partitioning member which has a third exhaust chamber formed therein. An exhaust inlet introduces exhaust gas from an engine into the first exhaust chamber. First communication bores provide communication between the first and second exhaust chambers, and second communication bores provide communication between the second exhaust chamber and the third exhaust chamber. The third exhaust chamber is open to the atmosphere through an exhaust outlet pipe. An exhaust emission control catalyst is carried on an outer surface of the partitioning member facing the first and second exhaust chambers, as well as on an inner surface of the partitioning member facing the third exhaust chamber. An inner surface of the muffler body does not carry the exhaust emission control catalyst.

Abstract: An exhaust apparatus has an exhaust pipe that receives exhaust gas from an engine and a muffler attached to the exhaust pipe. The muffler has an exhaust portion that discharges exhaust gas received by the exhaust pipe. A tubular member is attached to the exhaust portion and has an exhaust inlet portion for passage therethrough of the exhaust gas discharged through the exhaust portion and an opening portion formed oppositely from the exhaust inlet portion. A filter formed from metal fibers is disposed in the tubular member to reduce an exhaust noise created by the exhaust gas. A cap member is attached to the opening portion of the tubular member and has an exhaust outlet portion that discharges the exhaust gas from the muffler.

Abstract: The present specification discloses a muffler for attenuating exhaust noise from an internal combustion engine. The muffler includes a main chamber, an intermediate pipe, a diffuser chamber, a spark arrester, and an exhaust pipe. Exhaust gases from the engine enter the main chamber after which they flow through the intermediate pipe. The intermediate pipe extends back through the main chamber to the diffuser chamber. The spark arrester is a screen held within the exhaust muffler and removably coupled to the exhaust pipe. Gases flow through the screen to separate hot particles. The exhaust pipe extends within the main chamber, completing a 180° bend within the chamber before exiting the main chamber and the muffler. An outer enclosure may surround the muffler. A method of attenuating exhaust gas noise is also disclosed.

Abstract: The invention relates to an attachment pin (1) for fixing an exhaust-gas muffler (2) in an apparatus part (4) of a portable handheld work apparatus (5) driven by an internal combustion engine. The exhaust-gas muffler (2) includes especially an exhaust-gas catalytic converter (3). An at least partially exposed region (6) is provided with a cooling surface (7) and is on the attachment pin (1) between the exhaust-gas muffler (2) and the apparatus part (4).

Abstract: A pneumatic tool includes a shell with a chamber defined therein, a first passage communicated with the chamber and a second passage communicated with the chamber. A rotor is installed in the chamber for rotation when driven by pressurized air flowing into the chamber through the first passage. A shaft extends to the exterior of the shell from the rotor. A trigger is installed on the shell. A control device is put in the first passage and connected with the trigger for controlling the first passage. A muffler is put in the second passage. The muffler includes a plurality of balls.

Abstract: A silencer for silencing exhaust gases includes an acoustic resonator chamber that serves as a spark arrester to trap burning carbon particles and prevent them passing to the atmosphere. The silencer has an exhaust gas inlet and an exhaust gas outlet. Exhaust gases pass from the inlet to the outlet through a first passage and into a first chamber. The first chamber communicates with an acoustic resonator chamber by means of a connecting passage. The connecting passage is positioned adjacent the first passage so that sparks in the exhaust enter the acoustic resonator chamber where they are trapped. The silencer thus avoids the need for a separate spark arrester, as required by prior art silencers.

Abstract: The subject invention refers to a muffler comprising a muffler housing (1, 2) and generally a catalytic converter element (13) mounted in the housing, which muffler has at least one inner outlet (4) through which exhaust gases cleaned by the catalytic element (13) are intended to pass. Furthermore, according to the invention an outlet duct (30, 31) is arranged in connection to the outside of the housing, comprising a first section (30) for leading exhaust gases in a first direction (A) in parallel with the outside of the housing, and a second section (31) for leading exhaust gases in a second, opposite direction (B), whereby said first and second sections (30, 31) have an essentially equally large cross-sectional area. By way of this outlet duct an improved cooling of the exhaust gases before they are brought in contact with fresh air rich in oxygen can be achieved. A back-pulsation of fresh air into the muffler can also be prevented.