Abstract: The invention is directed to an exhaust gas muffler for an internal combustion engine such as a two-stroke engine for portable handheld tools such as a motor-driven chain saw. The engine includes a cylinder and a piston conjointly defining a combustion chamber wherein combustion gases are generated and discharged as a flow of exhaust gas during operation of the engine. The exhaust gas muffler includes a housing having a shell-like wall defining a chamber for receiving the exhaust gas from the engine. The housing has a primary outlet opening formed in the wall of the housing for passing a primary component flow of the exhaust gas out of the chamber in a first direction. The housing has a secondary outlet opening formed in the wall thereof for passing a secondary component flow of the exhaust gas out of the chamber in a second direction.

Abstract: An exhaust manifold muffler having an exhaust manifold portion 10 and a muffler portion 20 integral with the exhaust manifold portion 10. The exhaust manifold portion 10 includes a plurality of manifold pipes 11 having parallel downstream ends which are spaced from each other and are arranged in a row. Each manifold pipe is connected to a respective cylinder of an internal combustion engine such that exhaust presssure pulsations from the manifold pipes operate as reflected waves opposite in phase, so as to damp the pressure pulsations. The muffler portion 20 has a first muffler chamber 22 and a swirl pipe 29 installed in the first muffler chamber 22. The manifold pipes 11 extend tangentially into the first manifold chamber to produce a swirl in the first muffler chamber 22. Part of the swirl enters an upper inlet end of the swirl pipe. The swirl pipe 29 has a lower outlet end which is located between the downstream ends of the manifold pipes 11.

Abstract: The exhaust gases of both cylinder banks of a multi-cylinder reciprocating engine first flow through a catalyst situated along the respective cylinder bank and then, in a cross countercurrent, flow through a horizontally situated muffler arranged transversely to the cylinder banks.

Abstract: A car silencer includes an outer pipe having a front expansion chamber defined in a front portion of the outer pipe connected with a connecting tube which is connected to an engine manifold for directing waste gas as discharged from a car engine, an inner pipe detachably inserted in a rear expansion chamber in the outer pipe at a rear portion of the front expansion chamber, an absorbing and filtering medium filled in the inner pipe, and a perforated tail pipe inserted in the absorbing and filtering medium, wherein an engine exhaust gas will be reduced its sound in the front and rear expansion chambers and a plurality of pollutants laden in the exhaust gas will be absorbed, filtered and removed in the absorbing and filtering medium for preventing air pollution caused by an engine waste gas.

Abstract: An exhaust collector for use with an internal combustion engine of the type having a plurality of generally nested exhaust tubes for individually receiving exhaust gases from separate associated engine exhaust ports. The collector is frustoconically shaped and has an open upstream end sealingly engaged with the downstream ends of the exhaust tubes to receive exhaust gases directly therefrom. The collector is oriented with its generally conical shape convergent in the downstream direction, and includes an internal cone shaped stem piece oriented with its longitudinal axis coaxial of the collector. A base portion of the stem piece is nested between and extends from the downstream ends of the exhaust tubes, and an apex end of the stem piece is generally aligned with the collector downstream end. The collector interior wall defines a smooth cylindrical surface when taken in radial cross section at any position along generally the entire length of the axis of the collector downstream of the tube exit ends.

Abstract: A damped heat shield for a vehicle exhaust manifold includes inner and outer thin steel layers. An intermediate aluminum layer is located between the two steel layers. A high temperature corrosion-resistant coating is applied to the exterior surfaces and the edges of the shield. Such coating along the edges prevents the entry of corrosion producing substances into the interior of the shield. The outer steel layer has a thickness greater than the inner steel layer, so that the two layers do not resonate at the same frequency, and therefore, tend to damp vibrational energy more efficiently and reduce radiated sound energy and noise.

Abstract: An integral manifold-muffler-catalyst device (for an internal combustion engine having a plurality of combustion cylinders generating exhaust gases), comprising: (a) a monolithic catalyst having a plurality of aligned passages for effecting laminar flow of the exhaust gases therethrough while; (b) a high temperature resistant chamber assembly for close-coupling the catalyst to the engine having (i) an expansion chamber for substantially dissipating low frequency standing sound waves of said exhaust gases and for modifying high frequency sound waves of said exhaust gases and (ii) manifolding passages at one side of the expansion chamber for collecting and delivering the exhaust gases from the cylinders to the expansion chamber; and (c) means for effecting converging flow from said expansion chamber to and across substantially the full entrance face of said aligned passages, as well as from the catalyst, for effecting attenuation of high frequency sound waves carried by the exhaust gases.

Abstract: An improved automotive exhaust system comprises a flared expansion chamber having two inlet ports at its narrow end and three outlet ports at its wide end. The inlet ports extend a predetermined distance into the chamber to form therein a pair of lips that function as dams against migration of reversion pulses back up the exhaust pipes. The total area provided by the outlet ports is greater than that provided by the inlet ports. Exhaust gases fed to the chamber can thereby expand as they traverse the length of the chamber and can pass freely from the chamber through the outlet ports. Reversion pulses, which tend to migrate toward the inlet ports along the interior surface of the chamber, encounter and are reflected by the reversion dams and thus are inhibited from migrating back up the exhaust pipes to the engine. Engine performance and usable power is thereby enhanced.

Abstract: A nonmetal heat shield that is removably attachable directly to a muffler shell for preventing inadvertent contact with the hot shell surfaces of the muffler. The heat shield includes a plurality of raised boss portions for attaching the heat shield to the muffler shell. A non-metal spacer is located between the bottom surface of the raised boss portion and the fastening portion of the muffler shell to thermally insulate the heat shield from the muffler sufficiently to inhibit thermal degradation of the heat shield.

Abstract: A muffler housing consists essentially of two shell parts and is penetrated by pipes arranged between the shell parts. Fastening screws are inserted through the pipes into receiving holes at one of the shell parts and are accessible there.

Abstract: An internal combustion engine exhaust muffler formed to be dividable and integratable wherein an exhaust gas introducing tube and a pair of supporting pillars positioned substantially parallelly on both sides of the exhaust gas introducing tube are arranged within the exhaust muffler and a tubular member holding a cloth-like catalyst between holding screens is deformed to be substantially elliptically tubular and is hung over the pair of supporting pillars so as to enclose the exhaust gas introducing tube.

Abstract: An aquarium pump includes an air-delivery silencer connected with an air-pumping device encased in two covers mounted on a base portion having a silencing box provided with a plurality of sinuous air passages in the box for reducing a sound transmission speed and pressure of sound wave caused by the operating pump for greatly reducing its noise, and a metal plate embedded in a bottom plate formed in the base portion having a plurality of spring-like cushioning supporting legs secured under the bottom plate for further reducing vibrations caused by the operating pump for preventing noise pollution from an aquarium pump.

Abstract: A suction noise attenuator adapted for mounting on a tubular, suction conduit of a gas compressor, the conduit having a gas port through the wall thereof, the attenuator having a shell formed with generally opposed, first and second end walls and generally opposed first and second side walls, all of the walls having proximal and distal portions relative to the suction conduit, the proximal portions being resiliently deformable and the combined edges thereof providing a substantially continuous perimeter mounting face, a distal wall interconnecting the distal portions of all the walls to define an attenuation cavity, the mounting face further defining an inlet to the cavity, the edges of the end walls being concave and adapted to conform substantially to the periphery of the conduit as the attenuator is pressed thereagainst, at least one locator device on the shell adapted for coupling with at least one locator device on the conduit for operatively positioning the attenuator on the conduit to connect the port

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 compressor discharge gas muffler comprising a single expansion chamber and an impedence tube for attenuation the fundamental low frequency discharge gas pulses, and a side outlet positioned to attenuate higher frequencies. A method of attenuation is also disclosed.

Abstract: A catalyst according to the invention with its cooling package is an easily exchangeable unit that is plugged into an existing silencing device. The catalyst (29) is integrated with a perforated radiation protection and distribution plate (26) in front of it and furthermore with another plate behind it functioning as a lid (24) and fastening member against a silencer. Outside the lid there is a cooler attached which removes the heat. A waste gas outlet (32) takes place via a waste gas tube (23) to the rear corner of the silencer, where fan air, used for engine cooling, passes by. The waste gases get mixed to the fan air and the temperature will be reduced to an acceptable level.

Abstract: A muffler system for a working vehicle, particularly a lawn mower, comprising a main muffler body connected to an exhaust manifold of the engine, and a curved muffler cover covering the main muffler body from below. An exhaust pipe extends from the main muffler body laterally outwardly of the vehicle body, and defines an exhaust outlet for discharging exhaust gas in a direction away from a front wheel and the ground. Cooling air is blown by a cooling fan from the engine into the muffler cover. The muffler cover defines air exhaust openings for directing the cooling air forwardly of the vehicle body.

Abstract: An exhaust outlet conduit for internal combustion engines and adapted to function as a resonator for exhaust waves exiting from the cylinder or cylinders to which the conduit is connected. The conduit (4) is characterized by a combination of features, according to which the conduit exhibits an exhaust throughflow area which increases outwardly from the end of the conduit connected to the cylinder (1), and the conduit wall has provided therein one or more openings (5). The openings are so configured that the total opening area increases along the conduit in a direction away from the cylinder (1), so as to increase the frequency range over which the conduit (4) will function as a resonator.

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: Sound muffling devices for marine engines for installation on the external portion of the transom of a marine vessel are attached in such a manner that any breakdown within the silencer causes no discharge of exhaust gases or cooling fluids into the interior of the vessel and the gases and cooling fluid continue to be discharged overboard. The silencer is designed to reduce, substantially, the noise level emitted by the engine under operation by the efficient mixture of gases and water through a series of baffles, with low resistance to gas flow that does not diminish engine efficiency. The gases and odors are emitted from the vessel at the centerline with distance and direction such as to reduce, substantially, emissions into the air environment. The device receives exhaust gas and cooling water from an exhaust pipe passing through the transom at the side of the boat and directs the gas athwart the boat to the center where it is exhausted.

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

Abstract: 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 method of lining an exhaust manifold is disclosed, including applying a thin layer of a heat-resistant compound to the interior of an exhaust manifold; and bonding the compound to the manifold. The manifold may be in two or more sections when the compound is applied and the sections may subsequently be joined together to form the manifold. The compound may contain zirconium and/or may be a ceramic material.

Abstract: An exhaust system for a V-type six-cylinder engine having first and second banks each having three engine cylinders. The exhaust system includes first and second exhaust systems which are respectively connected to the first and second banks to be supplied with exhaust gas from the engine cylinders. Each exhaust system includes an exhaust tube connecting a catalytic converter and a muffler. The exhaust tubes of the first and second exhaust systems are communicated at a predetermined position by a communicating pipe member. The predetermined position corresponds to location of antinodes of the resonance sound pressure modes in the respective first and second exhaust systems which modes are reverse in phase to each other, so that resonance frequencies in exhaust noise are cancelled thereby to effectively achieve exhaust noise reduction.

Abstract: An exhaust manifold is, which includes a plurality of steel members having the same metallic crystal structure in a range of working temperature, which are jointed with each other by permanent welding and spot welding at different places, wherein material for the spot welding is a material having a different metallic crystal structure than that of the steel members.

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: 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: The invention relates to an exhaust gas muffler for a two-stroke engine of a portable handheld tool such as a chain saw. The exhaust gas muffler includes a catalyzer wherein high exhaust gas temperatures are developed because of the exothermal reaction which takes place therein. The catalyzer is located in the forward portion of a gas-tight hollow body mounted in the housing of the muffler. The hollow body has a tapered portion which extends out of the housing in the direction of the exhaust gas flow. In this way, the surface temperature of the muffler housing is reduced.

Abstract: An assembly for mounting an exhaust system and for connecting inlet means of said exhaust system to exhaust gas outlet means of an exhaust gas source structure of an internal combustion engine comprises a holder for carrying the exhaust system, metal bellows means fixed to the holder and secured to said exhaust gas source structure and connecting said exhaust gas outlet means to said inlet means, and a plurality of axial vibration dampers. In order to keep the deformations of the metal bellows within permissible limits and permit large forces to be taken up, six axial vibration dampers are provided, which are arranged around one or more metal bellows, only three of said vibration dampers have axes disposed in a plane, only two of said three axes are parallel to each other and the axes of the three other dampers intersect said plane and are parallel to each other or constitute a tripod having an apex spaced from said plane.

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: An exhaust muffler for an internal combustion engine, comprising a hollow casing defining a plurality of chambers which are communicated with each other by way of small holes, an exhaust inlet tube fixedly attached to an exhaust port of an internal combustion engine at its one end and fitted into the casing from a hole provided therein for communication with one of the chambers at its other end, and an exhaust outlet passage communicating another one of the chambers to the atmosphere. The internal end of the exhaust inlet tube and an opposing casing wall are joined by a threaded fastener while the exhaust inlet tube is provided with an annular shoulder surface which fits into the hole of the casing in an air tight fashion, so that the mounting of the muffler can be accomplished simply by fitting the casing of the muffler onto the exhaust inlet tube which is typically attached to a cylinder head of an internal combustion engine in advance and tightening the threaded fastener.

Abstract: An intake and exhaust flow improvement device for internal combustion engines is disclosed. The invention provides an anti-reversion chamber having a gas-redirecting profile on the intake side as well as providing a gas-redirecting profile on the exhaust side. The device also provides for toroidal loops placed within the exhaust and intake manifolds to have a swirling flow-enhancing effect by which the intake charge is continued to be held ready for the next opening of the intake valve and whereby the exhaust gases are smoothly exited from the exhaust manifold by providing a loop pathway to continue the one-way energy of the exhaust gases.

Abstract: A muffler cover has a plurality of air holes formed therein. At least part of the air holes is formed in such a manner as to have configurations which indicate characters or symbols, and at least those portions of the muffler facing the portions of the muffler cover that correspond to the air holes indicating the characters or symbols are coated with a heat resistant coating.

Abstract: The invention relates to an exhaust system for a multicylinder internal combustion engine comprising at least a manifold formed by individual exhaust ducts connected to the engine's cylinders, connector pipes, into which groups of individual ducts come together, a common exhaust pipe into which the said connector pipes join each other, the silencer mufflers, wherein the system is characterized in that the said silencer mufflers are positioned in correspondence of at least an end of said common exhaust pipe.

Abstract: In order to prevent the formation of a standing wave in the exhaust system one or more small transfer passages are formed either inthe body of the manifold or in the cylinder head. These passages permit exhaust pressure to be transmitted to the exhaust ports of the adjacent cylinders as well as into the exhaust conduiting. This destructively interferes with the formation of the standing wave and thus obviates the generation of exhaust noise.

Abstract: An exhaust manifold for attachment to an engine having a plurality of exhaust ports is provided. The exhaust manifold includes an exhaust conduit that is in fluid communication with selected exhaust ports, with the exhaust conduit being formed to include separate primary and auxiliary outlet openings. The exhaust manifold also includes a tuning tube that is formed to include an inlet opening that is in acoustic communication with the auxiliary outlet opening, and an outlet opening. The exhaust manifold also has a chamber for providing a static volume that is in acoustic communication with the outlet opening of the tuning tube.

Abstract: The apparatus would include a body portion positionable intermediate the exhaust manifold and the muffler or the catalytic converters if the car is adapted with such, so that exhaust gases, under a first condition, can flow through the body portion and into the muffler prior to exiting to atmosphere, and under a second condition, via the removal of a plate member, a greater portion of the exhaust gases would be exhausted directly out to atmosphere bypassing the remainder of the exhaust system including the muffler and/or catalytic converter.

Abstract: A muffler for work vehicle V-type internal combustion engines is disclosed, which is mounted in a horizontal sideway position, with its axis placed perpendicularly with the longitudinal vehicle axis, kept a proper distance from the chassis or vehicle body so that it is disposed in full exposure to the atmosphere for proper cooling. A pair of spaced inlet ports are provided in the muffler, at locations adjacent to opposite ends thereof for receiving the exhaust gases from the engine through a pair of parallely extending, parallel exhaust pipes directly interconnected between the combustion chambers of the two cylinders and the muffler inlet ports, without using the conventional intermediate flexible corrugated connectors.

Abstract: An improved muffler system for mounting within a restricted engine compartment such as the engine compartment of a small off-road vehicle including a muffler surrounded by a heat shield having a plurality of apertures formed therein for selectively cooling selected certain areas of the engine compartment in conjunction with a venturi which creates a flow of cooling air from outside the engine compartment, over the engine, into the apertures, between the heat shield and the muffler to a point where the exhaust gas and the initially cooler air are mixed and subsequently exited into the atmosphere.

Abstract: A motorcycle having exhaust pipes of equal length and a V-type engine having a front and rear cylinder block. The exhaust pipe associated with the front cylinder block extending directly back to above the rear suspension mount. The exhaust pipe associated with the rear cylinder block extends downwardly to beneath and around the rear suspension mount and then upwardly to above the rear suspension mount. Both exhaust pipes terminate above the rear suspension mount to connect with mufflers which extend upwardly and rearwardly adjacent to the back stay structure. The exhaust muffler systems are fixed to the back stay structure adjacent the aft end thereof. Pillion step brackets are fixed at the intersections of the back stay structure with the center frame members to insure appropriate strength in both the mounting and remaining in the frame.

Abstract: A stamped exhaust manifold for a small internal combustion engine having a stamped sheet metal housing including an inlet and an outlet. A sheet metal baffle is located in the housing opposite the inlet and spaced from the housing to form a dead air insulating pocket between the baffle and the housing. The baffle is positioned so that hot exhaust gas entering the manifold from the engine through the inlet port will impinge directly on the baffle and will be deflected thereby through substantially 90.degree. to the manifold outlet port.

Abstract: A pair of front exhaust pipes are joined to a rear exhaust pipe by an exhaust pipe joint. The front exhaust pipes have downstream end portions projecting into the exhaust pipe joint so that between the outer walls of the downstream end portions and the inner walls of the exhaust pipe joint there are formed annular spaces for receiving reflected waves travelling in the upstream direction and limiting the propagation of the reflected waves into the downstream ends of the front exhaust pipes.

Abstract: There is provided a suction device for a chain saw, comprising a suction chamber communicating with a suction port of a carburetor for an engine accommodated within the chain saw, and a muffling path formed within a rear handle of the chain saw to pass through said rear handle and provide communication between the suction chamber and atmosphere so that the suction noise of said engine is prevented from propagating outside due to the interference with the internal wall of said muffling path without providing separately for the chain saw a suction muffler or an air cleaner having a suction muffling path.

Abstract: An improved engine construction is disclosed having a valve train including valves and corresponding valve stems for controlling the intake and exhaust ports, cams for imparting reciprocating motion to the valves by way of the valve train, and a valve spring for biasing each valve toward its closed position and the valve train into tracking relation with the cam. The only element of the valve train coupling a cam to a stem is a cam follower with a depression for receiving the corresponding stem end and a cam engaging surface opposite the depression with the cam follower being held captive intermediate the stem and cam solely by the spring biasing of the stem toward the cam and the engagement of the stem end and the depression. Another feature of the engine resides in the engine block casting which includes an exhaust gas passageway extending from an engine cylinder and including near the end thereof remote from the cylinder an enlarged cavity which defines at least a part of a muffler shell.

Abstract: The spatially curved oscillator tubes are closely seated on the cylinder head and are partially integrated in that wall of a common intake housing which faces the cylinder head, and are completed by shell halves. The intake system preferably includes injection molded synthetic material, and is fastened on the cylinder head by an aluminum fastening rail or strip, or includes reinforced synthetic material, and is fastened directly on the cylinder head. An air-filter element can be installed as a part of the intake housing.

Abstract: A muffler device of a motorcycle including a muffler body for silencing the noise of exhausts of an engine located below the engine and connected to exhaust pipes which in turn are each connected to one of cylinders of the engine. Discharge pipes are connected to the muffler body to discharge the exhausts from the muffler body rearwardly of a motorcycle body.

Abstract: Disclosed in an exhaust muffler for internal combustion engine such as opposed twin cylinder 2-cycle internal combustion engine of simultaneous ignition type for driving a chain saw. The muffler is connected at a plurality of points thereof to portions of the engine such as cylinders, characterized by comprising a corrugation S for absorbing thermal distortion provided in at least one side wall of the part of the muffler between adjacent portions at which the muffler is connected to the engine.

Abstract: A suction silencer for suppressing generation of noise caused by gas or air sucked by a machine such as a compressor, internal combustion engine or the like. The suction silencer has amounting seat by which it is mounted on the suction side of a machine such as an internal combustion engine. The mounting seat has an opening leading to the suction port of the machine. An inversed conical surface protrudes from the peripheral edge of the opening. A lid member is attached to cover the inversed conical surface such that a small gap is left between the inner surface of the lid member and the large-diameter end of the inversed conical surface. The lid member has an inversed conical member which projects into the space defined by the conical surface so that an annular passage is formed between the inversed conical surface and the peripheral surface of the inversed conical member.

Abstract: An exhaust device for a 2-cycle engine including an exhaust pipe having an expanded portion, and a curved outlet pipe inserted in the exhaust pipe in such a manner that its one end opening is disposed in a position in the expanded portion in which the output power loss of the expanded portion can be decreased and its the other end opening is disposed at one side of the exhaust pipe. The use of a curved pipe as an outlet pipe enables the outlet pipe to be positioned such that its one end opening is disposed in a suitable position in the expanded portion while its the other end opening is disposed at one side of the exhaust pipe, thereby allowing the outlet pipe to have a suitable length and the volume of the resonance chamber in the exhaust pipe to be increased.