An exhaust apparatus includes a chamber disposed below an engine, an inlet pipe guiding exhaust gas from an exhaust pipe to the chamber, a tail pipe discharging the exhaust gas from the chamber to an outside, a first partition wall partitioning an inside of the chamber to a pair of left and right spaces, and a second partition wall partitioning one of the left and right spaces to a pair of front and rear spaces. Another of the left and right spaces is a first expansion chamber into which the inlet pipe enters. A rear space of the front and rear spaces is a second expansion chamber disposed downstream of the first expansion chamber. A front space of the front and rear spaces is a third expansion chamber disposed downstream of the second expansion chamber, and the tail pipe enters into the front space.

A muffler for a vehicle includes: a muffler shell; a baffle disposed within the muffler shell, and having a first opening and a second opening which allow an exhaust gas to pass therethrough; and a variable valve mounted on the baffle. In particular, the variable valve includes: a valve plate rotatably mounted to open and close the first opening of the baffle; a valve arm connected to the valve plate; and a valve actuator to move the valve arm by variations in pressure of the exhaust gas. The valve plate is capable of rotating in a plane parallel to a plane of the baffle.

An exhaust muffler for an exhaust system of an internal combustion engine, especially for a vehicle, includes a muffler housing with a flow volume (42), through which exhaust gas can flow, an exhaust gas inlet (28) and an exhaust gas outlet (36). A first resonator chamber (44) is open towards the flow volume (42) via a first resonator neck (68). A second resonator chamber (46) is open towards the flow volume (42) via a second resonator neck (74). A resonator pipe (52) provides the first resonator neck (68) and the second resonator neck (74).

There is provided an exhaust device that purifies exhaust gas discharged from an engine through an exhaust pipe. The exhaust device includes: a chamber that forms an expansion chamber of the exhaust gas at a downstream side of the exhaust pipe; a partition wall that partitions the expansion chamber into a first expansion chamber and a second expansion chamber; an introduction pipe that enters the second expansion chamber from a downstream end of the exhaust pipe; and a catalyst interposed at an intermediate portion of the introduction pipe in the second expansion chamber. The partition wall is formed with a first opening connecting an outlet of the introduction pipe to the first expansion chamber and a second opening connecting the first expansion chamber to the second expansion chamber, and the second opening overlaps with the catalyst when viewed from a side of the first expansion chamber.

A muffler for an exhaust system of an internal combustion engine, especially for vehicles with hybrid drive, includes a muffler housing (12), a heat exchanger unit (48), arranged in the muffler housing (12), for transferring heat from combustion exhaust gas to a heat transfer medium, an inlet pipe (38), a first outlet pipe (52) and a second outlet pipe (40). A first exhaust gas flow path (54), in the muffler housing, routs exhaust gas through the heat exchanger unit (48) to the first outlet pipe (52). A second exhaust gas flow path (56), in the muffler housing, routs exhaust gas to a second outlet pipe (40), bypassing the heat exchanger unit (48). A flow path blocking/releasing device (58) for blocking and releasing at least one exhaust gas flow path (54, 56), of the first exhaust gas flow path (54) and of the second exhaust gas flow path (56).

An exhaust muffler is made up of a plurality of layers including an exhaust passage pipe and expansion chambers, and includes a front assembly and a rear assembly sub-assembled separately from the front assembly. The front assembly includes a front exhaust passage pipe, a front muffler body disposed in covering relation to the outside of the front exhaust passage pipe and cooperating with the front exhaust passage pipe in making up double-walled pipes, and an exhaust valve disposed in the front exhaust passage pipe. The rear assembly includes a rear exhaust passage pipe and a rear muffler body disposed in covering relation to the outside of the rear exhaust passage pipe and cooperating with the rear exhaust passage pipe in making up double-walled pipes. There is thus provided an exhaust device for an internal combustion engine in which the accuracy of a position where the exhaust valve is installed is high.

A low emissions 2-stroke natural gas fueled engine includes at least one cylinder with an exhaust port in communication with a silencer-catalytic converter unit. The unit has first and second volumes in communication with each other. The first volume damps spurious exhaust pressure excursions and removes particulates in the exhaust. The second volume houses an oxidation catalyst for treating exhaust to reduce exhaust emissions. The engine oil has at most 10 ppm zinc content to reduce metal poisons contained in the exhaust prior to contact with the oxidation catalyst. The engine oil preferably has a very low ash content to minimize sulfur combustion components in the exhaust to reduce masking of the oxidation catalyst. The first volume preferably has a pressure relief valve set to relieve at a pressure greater than the maximum normal operating pressure of the engine to avoid excessive pressure excursions of the engine exhaust from damaging the oxidation catalyst.

A combined exhaust gas noise silencer consisting of a system of hollow elements with a mutual housing comprising a front face of the silencer connected to the supply pipe of exhaust gases, and a rear face of the silencer with an outlet from the rear face of the silencer, where the original—inlet exhaust gas (İ.sub.p) carrying a noise wave is divided into at least two flows—an exhaust gas flow (İ.sub.z) carrying a shifted noise wave with delayed wave length, and an exhaust gas flow (İ.sub.n) carrying a non-shifted noise wave, which are subsequently combined into a common exhaust gas flow (İ.sub.s).

There is provided a muffler structure of a saddle-type vehicle. The muffler structure is disposed at a downstream side of an exhaust pipe extending from an exhaust port of a cylinder head. A pipe is connected to the exhaust pipe and inserted into a muffler main body. The muffler main body includes a cylindrical portion and a reduced diameter portion joined to a downstream side end portion of the cylindrical portion and having a diameter reduced toward the downstream side thereof. The pipe includes a center pipe passing through the cylindrical portion, and a tail pipe disposed in the reduced diameter portion. An expansion chamber is formed by a space in the reduced diameter portion in the vicinity of the tail pipe.

A device for the aftertreatment of exhaust gases of an internal combustion engine, having at least one catalytic converter, through which exhaust gas can flow, and at least one muffler formed by a closed volume and through which exhaust gas can flow along an inflow section to an outflow section. The catalytic converter is formed by a honeycomb body that has a plurality of flow channels through which exhaust gas can flow. The honeycomb body is accommodated in a casing tube, which surrounds the honeycomb body, and is connected to the casing tube in a materially bonded manner. The catalytic converter is arranged in the interior of the muffler.