Abstract: An engine body of the multiple-cylinder engine for an outboard motor can include a crankcase for supporting a crankshaft whose axis extends vertically, and plural cylinders that are vertically arranged in line, each cylinder horizontally extending outward from the crankcase, and each cylinder having a respective exhaust port formed in a cylinder head. There are can be provided plural exhaust passages, each passage extending from the downstream end of the exhaust port, each passage communicating with the exhaust port and expansion chambers. Each expansion chamber can communicate with the extending end of the exhaust passage.

Abstract: An exhaust system comprising a catalytic converter unit, a bushing element provided in a shell wall of the catalytic converter unit, and an oxygen sensor positioned within exhaust flow of the catalytic converter unit and extending through the bushing element and having a connector disposed in intimate contact with the bushing element, and a method of positioning such an oxygen sensor in an exhaust system component.

Abstract: An air gap-insulated exhaust manifold for internal combustion engines. The manifold includes a flange with openings for fastening elements and further openings, which align with the cylinder exhaust ports of the internal combustion engine. A gas-tight outer shell is connected to the flange. An inner shell is provided with openings, which align with the cylinder exhaust ports of the internal combustion engine. The outer shell has a trough-shaped lower part and a hood-shaped upper part, which is welded gas-tight to the lower part. The inner shell has a trough-shaped lower part and a hood-shaped upper part. The outer shell is connected to the flange in a gas-tight manner. The inner shell is firmly attached to the outer shell at only one place.

Abstract: An exhaust manifold has a structure such that an end portion of a collecting section where pipes connected to respective cylinders of an engine are collected is connected to an exhaust pipe via a joint tube member. The joint tube member is constituted by an upper joint portion and a lower joint portion, and cut-out grooves are formed on both joining portions of the upper joint portion or the lower joint portion. With the cut-out grooves, a partition plate is engaged to be positioned, and in this state, the partition plate is fixed to the upper joint portion or the lower joint portion.

Abstract: A housing for a turbocharger forms a housing jacket (6, 7) which surrounds a rotor space (15) for receiving a turbine rotor (18). The housing jacket consists of sheet metal at least in part. A connection pipe (4?) provides for communication with an exhaust gas manifold (3, 4) of a combustion motor (20). To reduce heat losses, it is not only the housing jacket (6, 7, 22) which surrounds the rotor space (15) and consists of sheet metal, but at least the connection pipe (4?) for communication with the exhaust gas manifold (3, 4) is shaped of sheet metal and is in heat conductive connection with the sheet metal of the housing jacket (6, 7, 22).

Abstract: An exhaust header having a recessed sealing surface that receives an annular graphite gasket for affecting a fluid tight seal. The exhaust header further includes one or more exhaust head pipe flanges and one or more exhaust head pipes. Each exhaust head pipe flange is fixedly attached to one of the exhaust head pipes to form a passageway through the exhaust header. During installation, each exhaust head pipe flange is aligned with a passageway from an exhaust port of an internal combustion engine. A one to one registration between the exhaust head pipe flanges and the exhaust ports is achieved. The gasket circumscribes the exhaust port when the exhaust header is aligned with the surface of the internal combustion engine. Torquing of one or more fasteners compresses the gasket against the surface of the internal combustion engine to form the fluid tight seal between the passageways of the exhaust port and the exhaust header.

Abstract: An internal combustion engine includes a plurality of cylinders (1 through 12) and at least one turbocharger (2) and at least one exhaust manifold (13) which passes exhaust gases from two or more cylinders (5, 6) to the turbocharger (20), wherein the exhaust manifold (13) has a region (15) cooled with a cooling device and a substantially uncooled region (14).

Abstract: An exhaust manifold has a head flange constructed for receiving at least two exhaust pipes arranged side-by-side, and includes spaced apart first and second longitudinal flange portions. A mounting assembly is provided for sealingly securing the exhaust manifold to a cylinder head of an internal combustion engine and includes a mounting rail formed with a shoulder which laps over the first longitudinal flange portion and contacts the first longitudinal flange portion in a spring-elastic manner. Plural screw fasteners at least indirectly clamp the second longitudinal flange portion to the cylinder head.

Abstract: A turboscreen for use with diesel exhaust systems comprises a plurality of parallel metal V-shaped wires joined with a peripheral band. The turboscreen is reversibly provided within a housing assembly that permits removal of the interior screen without detaching the housing assembly from the exhaust system. The interior screen can be removed from the housing by removing and/or loosening bolts that connect the plates of the housing and withdrawing the screen. Maintenance times and repair costs are thereby reduced.

Abstract: An exhaust manifold is provided with deflector members positioned between downstream gas inlets and a main gas passage. The deflector members redirect the flow of exhaust gas from the inlets into the general direction of the gas flowing in the main passage as the exhaust gas enters the main passage.

Abstract: An exhaust system for a multi-cylinder engine can include a plurality of exhaust pipes with first upstream ends connected to exhaust openings of a multi-cylinder engine, and a collecting pipe connected to the second downstream ends of the exhaust pipes for collecting exhaust introduced from the exhaust pipes and directing it to a silencer. The collecting pipe has a front-end portion communicated to exhaust passages of the exhaust pipes, a middle portion for collecting the exhaust introduced from the front-end portion, and a rear-end portion for further collecting the exhaust introduced from the middle portion. The middle portion is provided with exhaust control means for controlling the area of the exhaust passages in accordance with engine speed.

Abstract: A heat shield structure of an exhaust manifold and a catalyst has a flange which is provided in a connecting portion connecting the exhaust manifold and catalyst and forms an open channel, an exhaust manifold heat shield member which covers an upper surface of the exhaust manifold, and a catalyst heat shield member which covers an upper surface of the catalyst. In the heat shield structure, an open side of the channel faces to the catalyst's side, a rear end of the exhaust manifold heat shield member is arranged on a vehicle body upper side of an end portion of the flange, and a front end of the catalyst heat shield member is arranged on a vehicle body floor side of the end portion of the flange. By this structure, heat from the exhaust manifold and catalyst can be efficiently released.

Abstract: A two cycle internal combustion engine cylinder having a piston chamber. The cylinder includes transfer ports; and an exhaust port divided into at least two sections. A first one of the sections has an aperture at the piston chamber with a top surface located closer to a top of the piston chamber than a top surface of an aperture of a second one of the sections at the piston chamber. The first section has a cross-sectional area which is smaller than a cross-sectional area of the second section. The aperture into the first section is located further away from the transfer ports than the aperture into the second section.

Abstract: A heat shield for an internal combustion engine used in a boat, or other application where engine compartment heat is unwanted, has a water cooled body positioned around, but spaced apart from, the exterior surfaces of the exhaust manifold of the engine. The concavity of the heat shield body fits the manifold and engine closely, to intercept and carry away radiant and convective heat. The shield is held in place by means of a boss which is captured between the exhaust manifold and the exhaust pipe of the engine. The shield enables industrial engines to be adapted to marine use without re-certification to meet environmental regulations.

Abstract: The invention relates to an engine arrangement that increases the degree of freedom of the engine state sensor while decreasing the size of the engine body. More specifically, the engine is formed with a chamber for housing a valve train and serving dually as a return oil path of the lubricating oil after having lubricated the valve train. The engine includes an oil temperature sensor partially exposed on one side of a cylinder block and an exhaust pipe partially exposed on the opposite side of the cylinder block.

Abstract: An exhaust header modeling apparatus includes a plurality of interchangeable straight and curved short cylindrical segment members which are selectively and releasably joined together end-to-end manually and rotated relative to one another to form a full-scale three-dimensional model of a desired engine exhaust header design or configuration. The segments are provided in sets having outside diameters corresponding to the outside diameters of conventional exhaust header tubing and have a circumferential scale at each end to visually determine the relative rotation between one segment and an adjoined segment. When assembled, the model provides optimum header layout and pathways to accurately fit within an available space, and provides accurate dimensions to aid in cutting forming sections of the exhaust headers from pre-bent metal tubing sections and the proper relative rotation between them.

Abstract: A system for attenuating exhaust noise from an engine with a first group of active cylinders and a second group of deactivatable cylinders includes a first exhaust manifold connected to the first group of active cylinders and a second exhaust manifold connected to the second group of deactivatable cylinders. The second exhaust manifold is connected to the first exhaust manifold such that the second exhaust manifold acts as a resonator to attenuate sound from the first group of active cylinders when the second group of cylinders is deactivated.

Abstract: A housing for a turbocharger comprises a housing shell which surrounds, at least partially, a rotor space, at least one manifold of a combustion engine, a pipe for connecting the housing shell with at least one manifold of the combustion engine, and a cylinder head of said combustion engine. All these parts are integrally cast as one single piece. This may be effected by a method which comprises the steps of: joining and bonding sand cores for part of a housing shell of the turbocharger with sand cores for shaping the cavities of the manifold, and these, in turn, with sand cores for shaping the cylinder head. Subsequently, inserting said joint and bonded sand cores into respective firmly interconnected molds for molding said part of a housing shell of said turbocharger, for said manifold and said cylinder head, and filling molten metal into said molds and allowing solidification of said metal.

Abstract: Either or both of an exhaust pipe coupled to the output end of an automobile engine collector pipe or the plurality of pipes coupled to the input apertures of the collector pipe from the engine are apertured along their lengths and contained within a further surrounding pipe in providing an exhaust which simultaneously serves as a muffler for the vehicle and to traverse the various component parts of its exhaust system and/or the vehicle engine when composed of a plurality of pipe segments, individual ones of which are of preselected length, and cut at their respective ends at preselected angles for joining together in appropriate orientation.

Abstract: A vibration and heat insulating board fixed so as to cover at least part of a heat source while forming a gap against the heat source surface, in order to lessen diffusion of heat from the heat source fixed in a vibration source, in which the heat source and the vibration and heat insulating board are coupled by means of a collar member having a pair of locking pieces fitted to the vibration and heat insulating board main body and bolted to a mounting part of the heat source, and ring-shaped coil members interposed between the pair of locking pieces of the collar member and the vibration and heat insulating board main body.

Abstract: Exhaust system assemblies employ wire bushings for thermal compensation to minimize noise due to “stick-slip” while the system cools. In a preferred embodiment, the wire bushings are formed of at least one strand of wire coiled about male end portions of pipe sections used in the system, each of which male end portions are inserted into a female end portion and held therein by an interference fit. The strand of wire is spot welded at spaced locations to the male end portions to provide bearing surfaces between the spot welds that move slightly as the exhaust system heats and cools to relieve thermal stress in small, substantially inaudible increments.

Abstract: An exhaust structure for use in an outboard engine of a vertical-type four-cycle V-type having cylinder heads, a crankcase, cylinder blocks constituting left and right sides of an integral body disposed in a V shape as seen in a plan view and forming a V-bank therebetween, an intake system disposed in the V bank, exhaust systems disposed on the left and right sides outside the V-bank, and a crankshaft disposed substantially vertically to the surface formed where the crankcase and cylinder blocks join one another, wherein the engine is disposed above an engine support attached to the hull and an oil pan is disposed beneath the engine support. The exhaust systems join and become integral inside the engine support and then pass through the interior of the oil pan to discharge exhaust gases. The invention provides an outboard engine exhaust structure having a non-complex oil pan of sufficient capacity.

Abstract: A motorcycle exhaust control system for covering exhaust cross-over pipes is comprised of an elongate tubular crossover block-off member having a side wall. The crossover block-off member side wall has a slit extending the length thereof. The crossover block-off member forms the springed structure capable of placement in a motorcycle exhaust pipe. The crossover block-off member is capable of self-detainment in the motorcycle exhaust pipe. The crossover block-off member is capable of blocking the motorcycle exhaust pipe crossover.

Abstract: An exhaust system for a dual crankshaft engine system having a first engine and a second engine having a common exhaust member open at an end thereof for venting engine exhaust. A first exhaust member is adapted to be coupled to the first engine and coupled to the common exhaust member. The first exhaust member has a first catalytic converter formed thereon. A second exhaust member is adapted to be coupled to the first engine and coupled to the common exhaust member and has a second catalytic converter formed thereon. A third exhaust member is adapted to be coupled to the second engine and coupled to the common exhaust member. A fourth exhaust member is adapted to be coupled to the second exhaust engine and coupled to the common exhaust member. A third catalytic converter is provided in the exhaust member.

Abstract: The present invention 10 discloses an exhaust header having heat sinks forming an integral part of the header conduit 14. The heat sinks are in the form of a plurality of radially positioned longitudinal fins 20 extending between the distal ends of the exhaust header 26. The extruded fins 20 welded at 24 to the engine exhaust conduits 14 tapering at 22 toward the flange 16 which is fixedly attached to the engine. At the other distal end a large, three-inch collector 18 is disposed having a rotating flange 30 with apertures 32 therein which flange encircles the collector. In an alternative embodiment, breaks 28 are provided in the fins. The present invention 10 is designed to improve cooling efficiency, reduce engine compartment temperature and provide greater overall structural integrity of the header pipes.

Abstract: An equal length crossover pipe exhaust system for an engine of a vehicle includes a plurality of exhaust manifolds for connection to outlets of cylinders of the engine. The equal length crossover pipe exhaust system also includes a plurality of crossover pipes having one end connected to the exhaust manifolds and extending above the engine. The equal length crossover pipe exhaust system further includes a main takedown pipe connected to another end of the crossover pipes at an equidistant point above the engine to provide an equal length junction point between the crossover pipes.

Abstract: A heat shield includes an inner portion, an outer portion, first and second insulating portions, and a deflecting portion. The inner portion includes a reflective material to reflect thermal energy that radiates from a heat/acoustic source. The outer portion includes a rigid material to provide structural support for the heat shield. The first and second insulating portions are intermediately positioned between the inner and outer portions. The deflecting portion is intermediately positioned between the first and second insulating portions to deflect acoustics from the heat/acoustic source. A method for manufacturing the heat shield is also disclosed.

Abstract: In an exhaust manifold of a four-cylinder engine four cylinders of which line up in order of cylinder #1, cylinder #2, cylinder #3 and cylinder #4, temperature rise performance of a manifold catalyst improves by shortening a total length of the exhaust manifold while preventing exhaust gas interference between the cylinders. Therefore, an exhaust manifold branch of cylinder #1 and an exhaust manifold branch of cylinder #4 in outward sides of the engine that are not fired in succession are made convergent with its convergence angle ?1 being equal to or below 20 degrees to form a first convergent exhaust manifold branch and an exhaust manifold branch of cylinder #2 and an exhaust manifold branch of cylinder #3 between the cylinder #1 and cylinder #4 that are not fired in succession are made convergent at a minimum distance having a laterally projected shape to form a second convergent exhaust manifold branch.

Abstract: An exhaust manifold of an engine exhaust apparatus includes a plurality of exhaust branches and a straight pipe section. The exhaust branches extend toward a confluence portion, from respective upstream ends to be connected with cylinders of an engine. The straight pipe section extends from the confluence portion toward a downstream end adapted to be connected to an exhaust purifying catalyst.

Abstract: An exhaust gas manifold of an exhaust system for an internal combustion engine includes a diverging pipe elbow and exhaust pipes. Each exhaust pipe has an end and is connected to the diverging pipe elbow. The ends of the exhaust pipes extend substantially unidirectionally into the pipe elbow. The sections of the exhaust pipes adjacent to the ends are joined and together form a circular cross section. The portions of the exhaust pipes adjacent to the joined sections are separated from each other with a gap.

Abstract: An exhaust muffler system for use on a motorcycle or four-wheeled vehicle provides for operation in either of two modes, a regular configuration that provides a high degree of noise reduction, or a racing specification that provides for a freer-flowing exhaust. Without changing the main body of the muffler, an operator can choose between a quieter, public road setting or a louder, high performance setting. The muffler is provided with two interchangeable spark arresters, and a main body having multiple expansion chambers therein, defined by bulkheads. When a regular spark arrester is installed, exhaust gas passes through one bulkhead three times, greatly reducing the noise produced. With the spark arrester removed, the exhaust gas passes straight through to the open air, enhancing performance. A seal is provided between the bulkheads and the spark arrester, which provides for extension or retraction in the lengthwise direction of the tail pipe.

Abstract: An exhaust manifold (10) of the present invention comprises a liner (12) that includes inner surface (14) defining manifold passages and an outer surface (16). The exhaust manifold (10) includes a shell (18) of a homogeneous and continuous material disposed over the outer surface (16) of the liner (12). The shell (18) and liner (12) of the exhaust manifold (10) include first (60) and second (72) composition formed from ferrous and non-ferrous metal powders (62), ceramic powder (64), and a binder (74) added thereto to form the manifold (10). The invention discloses a method of making the exhaust manifold (80). Accordingly, the exhaust manifold (10) of the subject invention has a reduced weight and dissipates heat energy contained in the exhaust thereby increasing the efficiency of the catalytic converter (42).

Abstract: A plurality of pipes adapted to be jointed to the exhaust ports of one line of an engine are joined together into a manifold comprising an equal number of pipe stubs, each receiving one of said pipes. The pipe stubs lead to a box from which extends a conduit that is jointable to terminal parts of the exhaust system, and each of them is flared at its jointed end, against which an annular gasket surrounding the respective pipe is pressed to abut by elastic elements.

Abstract: Exemplary methods, devices, and/or systems are suitable for regenerating a plurality of after-treatment units. An exemplary method includes selecting less than all of a plurality of after-treatment units and adjusting air to fuel ratio for less than all of a plurality of combustion chambers of an engine to thereby cause the selected after-treatment units to receive exhaust having hydrocarbon and oxygen concentrations that favor regeneration of the selected after-treatment units. Other exemplary methods, devices and/or systems are also disclosed.

Abstract: A structure of an exhaust manifold branch collecting portion includes a double collecting pipe 21 for collecting a plurality of exhaust openings 11A, 17A. The double collecting pipe 21 is comprised of an inner pipe 21-1 and an outer pipe 21-2, which are connected integrally to each other. In a space formed between the inner pipe 21-1, the outer pipe 21-2, and a ring-shaped stainless steel cushion member 22-2, a tubular cushion member 22-1, which is thermally expanded and foamed, is arranged as a restricted cushion structure.

Abstract: An exhaust system of a multi-cylinder internal combustion engine, particularly in a motor vehicle, has a first exhaust-gas line for receiving the exhaust gas from a first cylinder group of the internal combustion engine, a second exhaust-gas line for receiving the exhaust gas from a second cylinder group of the internal combustion engine, an exhaust-gas expansion chamber and an exhaust-gas outlet line, leading out of the exhaust-gas expansion chamber. The first and second exhaust-gas lines lead into an exhaust-gas mixing chamber which is coupled in gas flow communication with the exhaust-gas expansion chamber, so that exhaust gas can expand via the perforation of the exhaust-gas mixing chamber, into the exhaust gas expansion chamber.

Abstract: A method is presented for determining the fuel/air ratio in the individual cylinders (single cylinder lambda) of an internal combustion engine having a plurality of cylinders, whose exhaust gases mix together in a common exhaust gas pipe system, from the signal of an exhaust gas probe, whose mounting location lies in the common exhaust gas pipe system, with the aid of an invertible model for the intermixing of the exhaust gases at the mounting location of the exhaust gas probe. The method is distinguished in that, in the determination of the single cylinder lambda from the signal of the one exhaust gas probe evaluated with the aid of the inverted model, the rotational angle position of the exhaust gas probe at its mounting position is taken into consideration.

Abstract: An exhaust system for a V-type engine according to the embodiment of the present invention includes first and second front exhaust pipes that are respectively connected to first and second exhaust manifolds upstream thereof through first and second front catalytic converters. The first and second front exhaust pipes are joined together at end portions thereof to form a coupling portion. The center exhaust pipe is connected downstream of the coupling portion, and a main catalytic converter is disposed in the center exhaust pipe. The rear exhaust pipe is connected downstream of the center exhaust pipe. The coupling portion is formed such that an angle between a center line of an end portion of the first front exhaust pipe and a center line of an end portion of the second front exhaust pipe is less than 20 degrees.

Abstract: An exhaust system in an internal combustion engine has an exhaust manifold, an exhaust flange is connected to the exhaust manifold, and a turbocharger is connected to the exhaust flange. The turbocharger has an exhaust inlet flange connected to the exhaust flange. The exhaust manifold has a first passage and a second passage, and the exhaust flange has a first exhaust port and a second exhaust port. The exhaust ports of the exhaust flange each have a generally triangular cross-sectional configuration.

Abstract: A combustion chamber, in particular for a rocket drive, comprises at least one jacket made of a composite material with a ceramic matrix. The composite material contains a fibrous structure made of carbon-containing fibers, and the fibrous structure comprises layers of fibers that form a three-dimensional matrix.

Abstract: A double pipe exhaust manifold includes an inner pipe, an outer pipe formed in a cylindrical shape by joining at least one side edge thereof by welding, a space retaining member disposed in an annular space defined between the inner pipe and the outer pipe, a connection pipe connecting to a exhaust gas recirculation valve, and a mesh ring. Opening holes are formed in the inner pipe and the outer pipe so that the opening holes are opposed to each in a radial direction of the pipes. The connection pipe is connected to the opening hole of the outer pipe. The mesh ring is interposed between the inner pipe and the outer pipe in a state that the mesh ring plugs an annular opening part defined between opening edges of the opening holes.

Abstract: An exhaust system for an internal combustion engine of an outboard motor is provided. The exhaust system provides dual exhaust passages, simplifying the engine's construction and reducing manufacturing costs, while optimizing engine performance. The exhaust system includes exhaust ports having equal lengths that avoid differential pressure losses across cylinders. The arrangement of the exhaust passages enables a cowling to have a tapered aerodynamic design.

Abstract: An exhaust manifold is disclosed that enhances the purification efficiency and lifetime of the catalyst in a catalytic converter. The manifold includes: a mixing chamber of a spheroidal shape having runners, each runner having one end connected to an exhaust port and the other end to the mixing chamber along the outer circumference thereof at an angle that causes rotation of the entering exhaust; and a diffuser to induce exhaust gas to diffuse widely before passing through the catalytic converter.

Abstract: A structure of an exhaust manifold branch collecting portion where a plurality of pipe members are joined integrally at their respective downstream ends, wherein a thickened portion is provided at the downstream end of at least one pipe member on a center side of the exhaust manifold branch collecting portion.

Abstract: An outboard motor includes an elastic seal lid attached to an under cover to form a hermetic seal between the under cover and an exhaust release pipe while closing an opening of the under cover from which an outlet portion of the exhaust release pip projects outwardly. The seal lid includes a tubular seal portion projecting from at leaser one surface of a plate-like body of the seal lid. The tubular seal portion has annular seal lips fitted around an outer circumferential surface of the exhaust release pipe. The tubular seal portion is elastically deformable relative to the lid body to thereby take up or absorb an offset between the exhaust release pipe and the opening of the under cover produced due to cumulative manufacturing and assembling tolerances of relevant parts of the outboard motor.

Abstract: An exhaust system of a combustion engine comprises at least one exhaust manifold with a plurality of inlet pipes for connection to exhaust ports of the combustion engine. The system comprises a collector device with a one-piece housing having at least two apertures for connecting the inlet pipes and one outlet opening connected to subsequent elements of the exhaust system, in particular to a catalyst converter housing.

Abstract: An exhaust system for use with a four-stroke engine having first and second cylinders. The cylinders generate exhaust pulses at uneven time intervals with respect to each other. The exhaust system includes a muffler and first and second exhaust pipes that communicate between the mufflers and the first and second cylinders, respectively. The first and second pipes being sized and shaped to deliver the exhaust pulses to the muffler at even time intervals with respect to each other.

Abstract: A plurality of pipes adapted to be jointed to the exhaust ports of one line of an engine are joined together into a manifold comprising an equal number of pipe stubs, each receiving one of said pipes. The pipe stubs lead to a box from which extends a conduit that is jointable to terminal parts of the exhaust system, and each of them is flared at its jointed end, against which an annular gasket surrounding the respective pipe is pressed to abut by elastic elements.

Abstract: An exhaust system for a V-type engine according to the embodiment of the present invention includes first and second front exhaust pipes that are respectively connected to first and second exhaust manifolds upstream thereof through first and second front catalytic converters. The first and second front exhaust pipes are joined together at end portions thereof to form a coupling portion. The center exhaust pipe is connected downstream of the coupling portion, and a main catalytic converter is disposed in the center exhaust pipe. The rear exhaust pipe is connected downstream of the center exhaust pipe. The coupling portion is formed such that an angle between a center line of an end portion of the first front exhaust pipe and a center line of an end portion of the second front exhaust pipe is less than 20 degrees.

Abstract: An exhaust system of a multi-cylinder internal combustion engine, particularly in a motor vehicle, has a first exhaust-gas line for receiving the exhaust gas from a first cylinder group of the internal combustion engine, a second exhaust-gas line for receiving the exhaust gas from a second cylinder group of the internal combustion engine, an exhaust-gas expansion chamber and an exhaust-gas outlet line, leading out of the exhaust-gas expansion chamber. The first and second exhaust-gas lines lead into an exhaust-gas mixing chamber which is coupled in gas flow communication with the exhaust-gas expansion chamber, so that exhaust gas can expand via the perforation of the exhaust-gas mixing chamber, into the exhaust gas expansion chamber.