Abstract: A manifold converter apparatus comprising a manifold housing including a plurality of inlets wherein each inlet of the plurality of inlets is mounted immediately adjacent an internal combustion engine exhaust port and a plurality of lead pipes wherein each lead pipe of the plurality of lead pipes provides an exhaust gas flow passage between one of the inlets and a manifold plenum and at least one catalyst coated substrate located within at least one of the inlets between at least one of the exhaust ports and one of the lead pipes. An advantage achieved includes quick light-off of the manifold converter apparatus after cold start of the vehicle engine.

Abstract: A stable, close-coupled catalyst, an article comprising the close-coupled catalyst and a related method of operation. The close-coupled catalyst comprises a catalyst support and a palladium catalytic component. Preferably and optionally, there are stabilizers including alkaline metal oxide, and rare earth metal components selected from the neodymium and lanthanum components. The close-coupled catalyst composition includes substantially no additional oxygen storage component such as praseodymium or cerium compounds. There is preferably a catalyst such as a three-way catalyst downstream of the close-coupled catalyst. The downstream catalyst preferably includes an oxygen storage component such as cerium oxide or praseodymium oxide.

Abstract: In order to reduce the exhaust gas emissions of automotive vehicle combustion engines including exhaust gas catalytic converters, the exhaust gases are caused to flow between the engine and the catalytic converter through conduit branches of different thermal caracteristics. Said conduit branches comprise a full load tube and a partial load tube, with the full load tube surrounding the partial load tube so as to provide an annular space between the full load tube and the partial load tube.

Abstract: Methods and apparatus for reducing the TPM level of a diesel engine exhaust stream by providing a suitable oxidation catalyst into the exhaust train. The oxidation catalyst may be incorporated into a thermal insulative coating on the inner surface of the exhaust train, particularly the exhaust manifold and exhaust pipes prior to the turbocharger. Alternatively, when the exhaust train includes a turbocharger, the catalyst can be in a separate monolithic unit between the engine and the turbocharger. The system may also include an improved diesel oxidation catalyst unit having a metal monolithic substrate. The oxidation catalyst can also be incorporated into a thermal insulative coating inside the cylinders, particularly on non-rubbing surfaces such as The invention also includes the use of a protective mullite top coat on the thermal coating. A further embodiment is the use of a stainless steel bond coat to bind the thermal coating to a metallic substrate, particularly an aluminum substrate.

Abstract: Catalyzers for purification of exhaust gases are disclosed including a housing, an inlet for supplying the exhaust gases to the housing, a first catalyzer within the housing adjacent to the inlet and a second catalyzer within the housing downstream of the first catalyzer, the first catalyzer having a smaller cross-sectional area than the second catalyzer, and the inlet being angled with respect to the longitudinal axis of the first catalyzer.

Abstract: Methods and apparatus for reducing the TPM level of a diesel engine exhaust stream by providing a suitable oxidation catalyst into the exhaust train. The oxidation catalyst may be incorporated into a thermal insulative coating on the inner surface of the exhaust train, particularly the exhaust manifold and exhaust pipes prior to the turbocharger. Alternatively, when the exhaust train includes a turbocharger, the catalyst can be in a separate monolithic unit between the engine and the turbocharger. The system may also include an improved diesel oxidation catalyst unit having a metal monolithic substrate.

Abstract: The catalytic converter configuration for exhaust systems of motor vehicles, in particular Otto engines, conducts the exhaust (at least in portions thereof) in two or more separate systems. Each system is provided with at least one catalytic converter with axial flow passages. The catalytic converters are combined into a shared monolith for the two systems which is provided with a partition at one or both of the end faces. The partition divides the cross section of the shell and it is positioned so close to the face of the honeycomb body as to be virtually seal-tight.

Abstract: An exhaust system for a v-configured transverse-mounted internal combustion engine includes a first passage for the first, front manifold exhaust gas stream having a adsorber structure disposed therein and a second passage for the second exhaust gas stream having an catalyst structure disposed therein. The catalyst and the adsorber comprise a single honeycomb adsorber-catalyst structure having a plurality of partition walls extending along an axial direction of the honeycomb structure. The partition walls form at least two portions including a catalyst portion having a catalyst layer provided thereon and an adsorber portion having a adsorber layer supported thereon. Specifically, the portions are separate from each other in a cross-section extending perpendicular to the aforementioned axial direction. The system further includes burn-off catalyst disposed downstream adsorber-catalyst structure.

Abstract: An in-line exhaust system for a v-configured transverse-mounted internal combustion engine includes a first passage for a first exhaust gas stream and a second passage for a second exhaust gas stream having a catalyst system disposed therein. An hydrocarbon adsorber structure having an inlet and outlet end, a desorption temperature and comprising a first substantially unobstructed flow region, and a second more obstructed flow region abutting the first region, is provided and positioned so that both the first and second exhaust gas streams are able to flow therethrough. A fluidics diverter is provided and disposed in the second exhaust gas stream upstream, and proximate to the first region, of the adsorber for diverting the second exhaust gas stream away from the said first region. The system additionally includes a burn-off catalyst disposed downstream from the adsorber.

Abstract: A catalytic converter having a catalytic core element comprising a rigid, foam-like, metallic material having interconnecting walls defining an open pattern of interconnected pores which join together to form irregular passages extending through the catalytic core element. The catalytic core element may be configured for placement within the exhaust manifold or exhaust pipe of an internal combustion engine or within a separate housing. The catalytic core element may be configured such that exhaust flow through the catalytic core element may be radial through the lateral portion of the catalytic core element and axial through the end of the catalytic core element.

Abstract: In a turbocharger and exhaust gas manifold arrangement on a multi-cylinder internal combustion engine comprising an exhaust gas manifold with an exhaust gas collection chamber having a discharge flange connected to a connecting flange of an exhaust gas turbocharger, the discharge flange and, accordingly, the turbocharger are arranged at a longitudinal end of the exhaust gas manifold adjacent the front end of the engine.

Abstract: An oxidation catalytic converter system for small spark ignited engines includes a housing containing a catalyst, an inlet for receiving exhaust gases from the engine, and an outlet for discharge of the exhaust gases from the housing after passing through the catalyst. Attached to the engine exhaust is a jet pipe that extends into the inlet in noncontacting relation to the housing, whereby the catalytic converter is vibrationally isolated from the jet pipe. Surrounding the jet pipe is an annular air gap through which ambient air is drawn into the housing and mixed with the exhaust gases for enhanced cooling and catalyst performance.

Abstract: An exhaust gas emission control system for a 4-cycle outboard engine is disclosed. The engine comprises a mounting member; an engine block mounted on the mounting member; an extension housing coupled to the mounting member and extending downward therefrom; and an engine oil pan mounted under the mounting member within the extension housing. The oil pan has a recess formed therein in the lengthwise direction. An exhaust gas expansion chamber is formed in the extension housing for receiving exhaust gas from the exhaust manifold of the engine. The engine exhaust emission control system comprises a catalyst assembly positioned in the exhaust gas expansion chamber, the catalyst assembly having a catalyst case aligned with the oil pan in the lengthwise direction thereof. At least a portion of the catalyst case is disposed in the recess in the oil pan.

Abstract: An engine exhaust emission control system in an outboard engine is provided. The exhaust emission control system has a catalyst unit mounted in an engine block exhaust gas passage in the outboard engine. The catalyst unit comprises a catalyst carrier having at least one catalyst element carried therein and a flexible porous bag having at least a portion of the catalyst therein. The catalyst unit is formed to be positioned within the engine block exhaust passage so as to extend therealong and the catalyst unit is removably inserted and detachably mounted in the exhaust gas passage.

Abstract: A number of embodiments of an exhaust system for outboard motors that includes a trap portion in a conduit which conveys the exhaust gases from an expansion chamber formed in the drive shaft housing to an underwater exhaust gas discharge. The trap portion has a horizontal section that is disposed above the water level, and various orientations are depicted. In addition, a catalyst is also provided, and the catalyst is protected from water also by the construction.

Abstract: An exhaust gas collecting and cleaning device for a multi-cylinder engine comprising an exhaust-gas manifold (1) constructed as a casting and an exhaust-gas cleaning device (5) mounted near the engine, attached to the exhaust-gas manifold (1) and comprising a housing (6) and at least one exhaust-gas cleaning element (14) bedded therein. A tubular section (12), which is constructed as a sheet-metal part and projects from the casting, is cast into the exhaust-gas manifold (1) at the outlet end region thereof. To this there is joined a downstream segment of the housing (6) of the exhaust-gas cleaning device (5). According to an independent embodiment, a downstream exhaust-gas guide element (such as a corrugated pipe) instead of the exhaust-gas cleaning device is joined in corresponding manner to the exhaust-gas manifold constructed as a casting.

Abstract: An integrated manifold, muffler, and catalyst device for an engine uses perforated ducts surrounded by a resonator volume. Exhaust flow is routed from the exhaust ports by the ducts to a close coupled catalyst. The combination of the perforated ducts with the resonator volume and close coupled catalyst reduces exhaust flow restriction while at the same time increasing catalyst performance and reducing noise emissions.

Abstract: An apparatus for purifying an exhaust gas for an internal combustion engine having units for the adsorption of HC gases in the exhaust gas, arranged in an exhaust manifold of the engine facing corresponding exhaust ports in such a manner that straight flows from the corresponding exhaust ports contact the corresponding adsorption units. A controller receives a signal indicating a temperature of one of a catalytic converter and the adsorption units. The controller sends a signal to a cooling apparatus, such as a fan, indicating a desired on condition of the cooling apparatus based on the temperature signal. The cooling apparatus is provided for generating air flows for cooling the adsorption units. The fan is operated when the engine, in a cold state, is started. The operation of the fan is continued until a catalytic converter arranged downstream from the adsorption units becomes effective, i.e. the temperature of the catalytic converter is higher than a predetermined value.

Abstract: An exhaust manifold catalytic warm-up converter for an automotive vehicle engine includes tubular runners having inlet and outlet ends and connectable at their inlet ends with exhaust ports of an engine. The runners are joined at their outlet ends with a common exhaust outlet. A generally helical twisted tape extends longitudinally in each of the runners between their inlet and outlet ends and laterally divides the runners into at least two parallel generally helical flow passages. The tape is porous and formed of a material having a predetermined thickness and porosity to encourage a flow of exhaust gases through pores of the tape between adjacent helical passages due to pressure gradients across the tape resulting from gas flow in the helical passages. The porous tape has a low thermal inertia for fast warm-up and is coated with a catalytic material for stimulating reaction of emissions in the engine exhaust gases passing through the exhaust manifold. Additional features and alternatives are disclosed.

Abstract: An exhaust poison trap for protection of catalytic converters in automotive exhaust systems includes a tubular housing having open ends and a peripheral wall internally defining an exhaust chamber, a helical wall longitudinally dividing the exhaust chamber into at least two longitudinally extending helical passages for exhaust gas flow and porous means substantially covering the interior of the peripheral wall and forming an outer periphery of each of said helical passages, whereby exhaust gas passing through the exhaust chamber is directed in a helical path through the helical passages, causing particulate matter in the gas to be accelerated outwardly by centrifugal force and trapped in the porous means, thus protecting a downstream catalytic converter from trapped catalyst poisoning particles such as zinc and phosphorous. The porous means may be coated to improve trapping or to aid catalytic reactions in the exhaust gases.

Abstract: A muffler for an internal combustion engine has an expansion chamber (31, 32) into which exhaust gas from the engine is introduced. The expansion chamber has a double wall (32A), with an inner panel (42) of the double wall (32A) having exhaust gas discharge portions (42A, 42B, 42C, 42D) with respective blowout holes (61, 62, 63, 64) for introducing the exhaust gas from the expansion chamber (32) into an air space (Sb) in the double wall (32A). From the air space (Sb), the exhaust gas is vented to the ambient through a discharge hole (37A) in an outer panel (42) of the double wall (32A ). A spark arrester screen (72) covers the discharge hole (37A).

Abstract: A catalyst degradation determination apparatus having O.sub.2 sensors provided at the upstream and downstream of a catalyst, detects degradation of the catalyst by, during A/F ratio feed-back control since an engine has been started, comparing an integrated value of output values from the upstream O.sub.2 sensor with that of output values from the downstream O.sub.2 sensor. Upon starting integration of the output values from the respective O.sub.2 sensors, change of activated status of the catalyst is judged. If the status of the catalyst is approximately the same as a previous status, the integration is started with previous integrated values. On the other hand, if the status of the catalyst is different from the previous status, the previous integrated values are reset, and the integration of the output values from the respective O.sub.2 sensors is started from the beginning. This prevents erroneous catalyst degradation determination.

Abstract: Disclosed herein is an internal combustion engine including a reactor including opposed first and second ends, an outer shell extending between the opposed ends, and a flow path extending between the opposed ends and including an entry opening at the first end, and a discharge opening at the second end, and an engine member including a plurality of spaced combustion chamber portions each including an exhaust port, an exhaust manifold communicating with the exhaust ports and with the entry opening and including a generally vertically extending open side including a portion closed by the reactor outer shell, and an outer wall spaced from the open side of the manifold and also engaging the outer shell of the reactor.

Abstract: An exhaust passage structure is provided for an outboard motor unit having an engine holder mounted to a hull through a bracket, an engine disposed to an upper portion of the engine holder, a drive shaft housing disposed to a lower portion of the engine holder and an exhaust passage structure extending from the engine into water through the drive shaft housing. The exhaust passage structure has an improvement in which first and second exhaust expansion chambers are disposed on the way of an exhaust passage of the exhaust passage structure, the second exhaust expansion chamber is disposed to an upper portion of the engine holder, an exhaust tube is disposed on an upstream side of another exhaust passage which communicates the second exhaust expansion chamber with the water so that an upstream side opening of the exhaust tube is directed upward in a mounted state.

Abstract: A plate-type catalytic converter includes a holder device and plates being coated with a catalytically active composition, being held one above the other in the holder device and extending in a main flow direction. The plates include first and second adjacent plates forming at least one reaction chamber. At least the first plate has an approximately corrugated first structure oriented obliquely relative to the main flow direction for deflecting a flow medium flowing along the first structure from the main flow direction.

Abstract: The exhaust emission containing large and small particles, discharged from an exhaust port of a cylinder No. 1 of an engine during a first exhaust stroke collides with a first adsorbent opposed to the exhaust port, so that some of the small particles of HC enter a connecting gas passage. Since the latter is not connected to a second adsorbent for a cylinder No. 3 in which a second exhaust stroke consecutively occurs, the exhaust gas discharged from the first cylinder can be easily introduced in the first adsorbent and in the connecting gas passage. When the cylinder No. 4 changes to an exhaust stroke, the exhaust gas discharged therefrom is introduced in the connecting gas passage through the corresponding adsorbent to move the HC remaining in the connecting gas passage toward the first adsorbent. Thus, the HC is adsorbed again by the first adsorbent and little is discharged into the air. Consequently, the HC adsorbing efficiency can be enhanced.

Abstract: In an internal combustion engine with at least two groups of cylinders of which each has an exhaust pipe with a catalytic converter and of which one group can be shut down so that it is inoperative during part-load engine operation, the exhaust pipes are joined downstream of the catalytic converters by a common pipe section, and vacuum generating means are provided for subjecting the exhaust pipe of the inoperative cylinder group upstream of its catalytic converter during part load operation when the one cylinder group is shut down to vacuum for pulling exhaust gas from the common pipe section into the catalytic converter of the inoperative cylinder group.

Abstract: A method and apparatus for desulfating a NO.sub.x trap is proposed wherein half of the engine cylinders are operated at a rich air/fuel ratio and half are operated at a lean A/F during the desulfation process. The two exhaust gas streams, the rich stream and the lean stream, are physically or chemically separated until they enter the NO.sub.x trap. A catalyzed exothermic chemical reaction is then generated in the trap. The resulting temperature increase is sufficient to remove SOX from the trap. During desulfation spark advance is adjusted to minimize event time imbalance.

Abstract: Muffler with catalytic converter (1) composed of a muffler housing (2) and a lid (3) which seals the muffler housing. A catalytic converter element is mounted in the lid and an exhaust pipe (5) leads from this element out of the muffler (1). The exhaust gas pipe (5) is located entirely in the lid, so that the exhaust gases are released via the lid (3).

Abstract: An outboard motor includes an exhaust emission control system which is arranged rationally and neatly in the housing of an outboard motor body, irrespective of various limitations on the outside shape of the housing. An oil pan disposed below an engine of the outboard motor has an oil holding portion, and an exhaust pipe is disposed vertically along a vertical wall portion of the oil holding portion. A catalytic converter is disposed in an intermediate portion of the exhaust pipe in confronted relation to the vertical wall portion. The catalytic converter has a particular shape in horizontal section which is greater in size in a first direction than in a second direction perpendicular to the first direction. A fresh-air delivery passage is provided for introducing fresh air into an exhaust passage disposed upstream of the exhaust pipe.

Abstract: An exhaust collector for collecting exhaust gases from a multiple cylinder combustion engine to a common flow includes primary tubes. To reduce mass and heat losses in the exhaust system, the peripheral walls of the collector are at least to a substantial part formed by the primary tubes.

Abstract: A muffler structure for an internal combustion engine is disclosed which is capable of diminishing occurrence of fraying and lowering of exhaust gas cleaning performance and durability, and which enables replacement of the catalytic cloth and the like to readily be carried out. The muffler structure for an internal combustion engine comprises a muffler 10 and a catalytic assembly 30 disposed in the muffler 10, the catalytic assembly 30 including a spark arresting wire mesh 32 and a catalytic cloth 37 fitted over the spark arresting wire mesh 32, the catalytic cloth 37 has its peripheral edge 37a covered entirely or in substantial part and retained with side walls 34, 34, 36 peripherally provided on the spark arresting wire mesh 32.

Abstract: A pollutant reducing exhaust manifold for an internal combustion engine incorporating a catalytic converter therein. The manifold has a plurality of header pipes connected to and receiving exhaust gases from respective ones of a plurality of exhaust ports of an internal combustion engine. The header pipes are connected to a single chamber with an outlet therefrom connected to an exhaust pipe as well as a catalytic converter structure having a catalyst disposed on a supporting substrate disposed in the chamber between the inlet(s) and the outlet so that all exhaust gases from the engine must pass through the catalytic converter structure. The catalytic converter operates at higher temperatures for increased efficiency and comes to operating temperature virtually immediately.

Abstract: An exhaust gas purifying device includes a cylindrical carrier carrying a catalyst, the carrier having a number of holes in the cylindrical wall thereof, an exhaust pipe into which the cylindrical carrier is inserted, an elastic member set radially compressed between a part of the outer cylindrical surface of at least one end portion of the carrier and a recess formed in the inner cylindrical surface of the exhaust pipe which is confronted with the part of the outer cylindrical surface, pressing pieces protruded from the outer cylindrical surface of the carrier so as to engage with the inner end face of the elastic member as viewed in the direction of axis thereof, the pressing pieces cooperating with the end of the recess to compress the elastic member axially, and a valve chamber formed in the exhaust pipe, the valve chamber having a valve body which includes a valve shaft penetrating the valve chamber in a direction of diameter, and a valve body fixedly mounted on the valve shaft.

Abstract: The device comprises, inside a cylindrical case (3) of the exhaust manifold (2), a catalyst body (12) in a central position and means (14) for adsorbing hydrocarbons in a peripheral position around the catalyst body (12). Preferably, the catalyst body (12) is disposed in an exhaust pipe (8) constituting an end part of an exhaust line (8a) and the adsorption means (14) is disposed in a peripheral annular space between the pipe (8) and the inner surface of the case (3) of the manifold.

Abstract: An exhaust muffler structure of an internal combustion engine in which a catalyzer is readily and easily mounted and removed to carry out the assembling work of the muffler and the maintenance work such as cleaning and replacing the parts of the muffler with ease; the generation of vibration and noise are to be prevented; and the purification capacity and durability of the catalyzer are to be improved. The exhaust muffler structure comprising: an exhaust muffler having inner and outer exhaust muffler halves which are detachably combined with each other; a communication hole formed on the exhaust muffler for guiding exhaust gas from an internal combustion engine to the exhaust muffler; a cylindrical member having a catalyzer between resilient supporting nets, characterized in that the cylindrical member is disposed in a space in the exhaust muffler with a body of the cylindrical member being supported between the both inner and outer exhaust muffler halves.

Abstract: An exhaust gas purification system for an internal combustion engine is herein disclosed which comprises an exhaust system having an adsorption flow path provided with an adsorbent capable of adsorbing harmful components such as hydrocarbons in an exhaust gas, and a catalyst flow path provided with at least one catalyst for decreasing the harmful components in the exhaust gas, the exhaust gas purification system being characterized in that an outlet of the adsorption flow path is joined to the catalyst flow path at a predetermined position on the upstream side of the catalyst to form a joint portion; the exhast gas produced at least at the time of the operation start of the internal combustion engine is divided so as to flow through the adsorption flow path and the catalyst flow path in a predetermined ratio, so that part of harmful components such as the hydrocarbons are adsorbed by the adsorbent in the adsorption flow path; and when the adsorbed harmful components begin to desorb from the adsorbent with the

Abstract: A multi-cylinder internal combustion engine is provided with a group of constantly operated cylinders and a group of cylinders that can be switched off. An exhaust line having a catalytic converter is associated with each group of cylinders. A shutoff element is disposed downstream of the catalytic converter of the constantly operated cylinder subassembly. In addition, the two exhaust lines or the two catalytic converters are connected to each other via a bypass line. Maintaining the temperature of the second catalytic converter is made possible via the bypass line, even when the cylinders of the second group are not operated and when the exhaust line is closed.

Abstract: A catalytic converter exhaust section comprises a first mounting plate, a second mounting plate, a hollow cylindrically shaped metallic tube and a plurality of substantially identical metallic catalytic converter substrates arranged in a honeycomb pattern. Each of the catalytic converter substrates has a regular hexagonal cross section and an inlet end separated from an outlet end by six planer walls. The metallic substrates are attached in parallel to form a compound honeycomb cross section with an inlet side, an outlet side, and an outer border defined by a portion of the planer walls. The compound honeycomb cross section is affixed within the tube between the first mounting plate and the second mounting plate. The individual substrates are coated with an appropriate catalyst for treatment of a particular exhaust component.

Abstract: A number of embodiments of exhaust systems for outboard motors including a combined catalyst bed and exhaust manifold forming member affixed within the cylinder block of the engine so as to be readily detachable for servicing. This combined member is provided with a separate cooling jacket for its cooling.

Abstract: A pollution arrestor removes various pollutants, such as soot, NO.sub.x, CO and hydrocarbons, from a gas stream. The pollution arrestor is composed in layers starting with a particulate filter to remove soot followed by various catalytic sections enhanced by radiofrequency microwave energy. The leaving gas is substantially reduced in pollution.

Abstract: In an engine exhaust emission control system, a ternary catalyst and a hydrocarbon adsorber are provided in an exhaust passageway from an engine. The ternary catalyst includes first passages through which an exhaust gas discharged from the engine flows, and second passages through which the exhaust gas which has flowed through the first passages and the hydrocarbon adsorber flows. The first and second passages are laminated to each other to enable heat exchange therebetween. The hydrocarbon adsorber is capable of being cooled by a cooling medium. Thus, it is possible to reliably prevent hydrocarbons in the exhaust gas from being released to the atmosphere during the cold start of the engine.

Abstract: A muffler for a two-stroke internal combustion engine having a housing and a partition wall which cooperate to define a first chamber adjacent an engine exhaust port and a second chamber remote from the engine. A catalyzer element is housed within the second chamber. A discharge pipe extends from an outlet of the catalyzer element and through the first chamber to atmosphere. An outer pipe surrounds a portion of the discharge pipe within the first chamber and cooperates therewith to define a passage whereby exhaust gas within the first chamber is directed through the partition wall and into the second chamber. Heat from the treated exhaust gas flowing through the discharge pipe is transferred to the exhaust gas flowing through the passage to preheat the exhaust gas prior to reaching the catalyzer element, thereby reducing the time required to bring the catalyzer element to an operating temperature following engine start-up.

Abstract: An object is to capture unburned fuel immediately after startup of an engine effectively. A vessel is disposed in an exhaust manifold of an engine and opened only at one end, its opening directed toward exhaust ports. Catalyst carrier is stored in the vessel. Since exhaust material has high specific gravity as compared to that of vaporized exhaust gas, the unburned fuel is exhausted rectilinearly from the exhaust ports due to its inertia, entering the vessel to be captured in the catalyst carrier. When the temperature of the catalyst reaches the temperature required for activating as the exhaust gas temperature rises, exhaust material is exhausted with purified condition. Since the vessel is opened only at one end, the current passing through this does not occur, making it possible to prevent the damage of the catalyst carrier due to the excessive high-temperature.

Abstract: A catalytic exhaust treatment system for an outboard motor wherein a catalyst bed is supported within the exhaust pipe on a support plate that permits the catalyst bed to expand and contract relative to the surrounding exhaust pipe from which it is spaced. The exhaust gases can flow through the catalyst bed and around the catalyst bed for complete treatment.

Abstract: A catalyzer-containing muffler for treating exhaust gas from an engine is disclosed. The muffler includes an outer casing defining a closed space therein and having an inlet pipe and an outlet pipe for introducing and discharging the exhaust gas into and out of the outer casing, respectively. At least one partition wall is provided so as to divide the closed space of the outer casing into two or more spaces. At least one penetration pipe is provided through each of the partition walls for placing the divided spaces in communication with each other, and a catalyzer is provided inside at least one of the penetrating pipes. Exhaust gas noise is thus reduced and at the same time toxic substances such as NO.sub.x or SO.sub.x are removed by the muffler by a single structure.

Abstract: In an exhaust gas system for an internal combustion engine for a vehicle which includes an exhaust gas conduit with an exhaust gas cleaner and a silencer, the structure-borne noise emission is reduced by coating surface areas of the exhaust system with a silencing layer consisting of metal powder which is applied by plasma spraying or sintering.

Abstract: A catalytic exhaust treatment system for an outboard motor wherein a catalyst bed is supported within the exhaust pipe on a support plate that permits the catalyst bed to expand and contract relative to the surrounding exhaust pipe from which it is spaced. The exhaust gases can flow through the catalyst bed and, around the catalyst bed for complete treatment.

Abstract: A manifold catalytic converter for automotive engines includes a flange provided on a cylinder head of the engine with a plurality of installation openings formed therethrough corresponding to exhaust ports of the engine. Tubes are connected to the installation openings with the other end of each of the tubes being attached to the vessel of the catalytic converter, aligned along a line of installation which is slanted relative the longitudinal direction of the engine so as to reduce transmission of vibrations from the engine to the vessel of the catalytic converter in directions transverse to the axial direction of the engine.

Abstract: An exhaust system of a transverse V-type or horizontal opposed type engine having front and rear cylinder banks includes: front and rear exhaust pipes which are respectively provided for the front and rear cylinder banks; front and rear catalytic converters which are respectively connected to the front and rear exhaust pipes; a joint exhaust pipe which is connected to the front and rear catalytic converters for collecting exhaust gas from the front and rear catalytic converters; and a combined exhaust pipe which is connected to the joint exhaust pipe. The combined exhaust pipe has a longitudinal axis which is substantially parallel to a longitudinal axis of the rear catalytic converter such that exhaust gas flow in the rear catalytic converter is in the substantially opposite direction to exhaust gas flow in the combined exhaust pipe. Each of the front and rear catalytic converters has an elliptical section.