Abstract: In an exhaust manifold for an internal combustion engine including a central part with tow exhaust gas flow ducts extending from the central part in opposite directions for collecting exhaust gas from first and respectively second cylinder groups of the engine, the center part includes a first control valve for controlling the exhaust gas flow from the first and the second cylinder groups to first and second turbine inlet flow passages, a second control valve for controlling the exhaust gas pressure and a third control valve for controlling the exhaust gas recirculation rate.

Abstract: The invention concerns an exhaust conduit (1) comprising an outer tube (3) and an inner tube (2) positioned inside the outer tube (3) so as to delimit, between those two tubes (2, 3), a peripheral volume (4) inside which is implanted a material (5) for thermal insulation of said conduit (1) and at one first end (6) of said conduit (1), first means (8) for connection to a first exhaust element and at a second end (7) of said conduit (1), second means (9) for connecting said pipe (1) to a second exhaust element comprised in said exhaust line. Said conduit (1) is characterized in that it comprises, proximate its second end (7), means (10) for preventing exhaust gases circulating inside the inner tube (2) from penetrating into the peripheral volume (4) delimited by said inner tube (2) and the outer tube (3).

Abstract: In an exhaust manifold, a plurality of branch pipes is bent downward from a head flange to form like an L-letter shape, where exhaust-gas upstream side end portions of the pipes are connected with an engine through the head flange and exhaust-gas downstream side end portions thereof are connected with a pipe collecting part which is provided with a sensor for detecting a state of exhaust gas. The pipe collecting part has a reduced diameter portion where a length of the pipe collecting part in a longitudinal direction of the head flange is set shorter than that of the pipe collecting part in a thickness direction of the head flange. The sensor is provided on the reduced diameter portion.

Abstract: A system comprising an engine having a first and second bank of cylinders, said first bank having a first and second group of cylinders, said second bank having a third and fourth group of cylinders; a first emission control device coupled to said first and second group for treating gasses from said first and second group separately; a second emission control device coupled to said third and fourth group for treating gasses from said third and fourth group separately; and a controller for operating said first and third group about stoichiometry and said second and fourth group to pump air without injected fuel.

Abstract: An assembly for establishing a water-tight seal for a conduit passing through a wall or other structure wherein the conduit conveys heated fluid, such as exhaust gasses. The assembly is adapted to minimize the heat transferred to the wall or other structure by creating a circuitous heat transfer path in conjunction with thermally insulating materials.

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 system for an internal combustion engine having a plurality of cylinders is disclosed. The exhaust system comprises a plurality of exhaust branch passages, an intermediate exhaust pipe section, a partition plate and a downstream pipe section. Each exhaust branch passage is in communication with a respective cylinder. The intermediate exhaust pipe section forms a passage that is in communication with the exhaust branch passages. The partition plate is provided in the intermediate passage and divides the intermediate passage into first and second flow paths. The partition plate further includes a projection positioned on a first surface thereof that is oriented so as to be generally perpendicular to the direction of exhaust flow. The partition plate is disposed within the intermediate passage so as to position the projection in the first flow path.

Abstract: An exhaust manifold made of heat-resistant cast steel comprising pluralities of flanges each having a hole connected to each exhaust port of a cylinder head of an engine with bolts, pluralities of ports connected to the flanges, and a convergence portion in which the ports are converging, the thickness of the flanges being 80-150% of that of the ports.

Abstract: An exhaust system includes a reverse flow heat exchanger having a plate separating an intake chamber and an exit chamber, each chamber having an inlet and an outlet located at opposing ends to allow flow therethrough. The plate can include a vane connected to the end of the plate in the vicinity of an inlet or an outlet. The vane is configured to reduce resistance to fluid flow near the intake chamber inlet. The exhaust system includes a heating manifold, such as a combustion chamber, configured to receive an exhaust stream from the intake chamber, further heat the exhaust stream, and return the exhaust stream to the exit chamber. Embodiments of the system can be configured to additionally perform as a catalytic converter and/or a muffler.

Abstract: An exhaust manifold is provided with a plurality of branch pipe parts and a collecting pipe part. The plurality of branch pipe parts are respectively connected to a plurality of exhaust ports of a multicylinder internal combustion engine. The collecting pipe part is formed by merging the plurality of branch pipe parts. The plurality of branch pipe parts and the collecting pipe part are formed by an upper shell member and a lower shell member superposed on each other. A partition plate is attached to at least one of the upper shell member and the lower shell member. The partition plate separates between exhaust gases flowing into the collecting pipe part from two of the branch pipe parts respectively connected to adjacent two of the plurality of exhaust ports.

Abstract: An exhaust system for a drive unit formed by the transmission and the engine, having exhaust-gas-carrying pipes and at least one muffler and catalyst housing. A holding part can be fastened to the transmission and/or the engine and on whose supporting leg the exhaust system can be fastened or suspended. A fastening clamp for accommodating a catalyst housing is provided on the end of the respective supporting leg.

Abstract: A manifold for exhaust gases from a motor vehicle engine, includes upper and lower half-shells (18A, 18B) delimiting between them an exhaust gas pipe, and aligned bores designed to be arranged in the extension of the engine exhaust outlets, the half-shells having each a peripheral edge and being attached to each other via at least first segments (20A, 20B) of their peripheral edges welded to each other. The invention is characterized in that there is at least one median plane (P) passing through the bores and traversed at least twice by the first segments (20A, 20B).

Abstract: A method of avoiding damage to a decoupling hose mounted between two tubes of a motor vehicle exhaust system, said hose comprising a deformable inner portion, an outer sealing leakproofing portion in the form of a continuous and leaktight sleeve having a flexible central zone and two rigid endpieces, and an intermediate portion in the form of a wad of thermal lagging extending substantially over the entire length of the outer sleeve, each rigid endpiece extending at least over a length such that its peripheral end edge connected to the flexible central zone overlies the inner portion of the hose which is subjected to deformation, wherein, in order to avoid any damage to the wad of thermal lagging by said peripheral end edge of each endpiece, the method consists in defining the effective length of the endpieces in such a manner that for the wad of thermal lagging having an initial thickness H0 and a compressed thickness Hc when compressed by said peripheral edge of each endpiece during maximum transverse defle

Abstract: An AI pipe (1) is formed with a first housing (11) and a second housing (21). The first housing (11) is made from a thin metal sheet and has a clamp portion (C1) that was left remaining. The second housing (21) is also made of a thin metal sheet and also has a clamp portion (C2) that was left remaining. When fitted together, the first housing (11) and the second housing (21) form a pipe portion (31). With this AI pipe (1), a through-hole (H) which is punched out by press working is formed in at least one of the clamping portion (C1) and the clamping portion (C2).

Abstract: An exhaust system (26) for a vehicle with a V-engine, aimed at increasing the output power of the V-engine, preventing heat conduction from the exhaust system to the parts around the exhaust system and enhancing the durability of the exhaust system is provided. A transmission and a transfer device (14) are connected in series to the V-engine with an output shaft extending in the longitudinal direction of the vehicle, the transmission and the transfer device (14) being provided in a tunnel (15) in a central portion of the floor (4) of the vehicle and protruding to an upper section of the vehicle, a pair of exhaust pipes (31, 32) being connected to each bank of the V-engine, the exhaust pipes (31, 32) converging into a convergence section provided under the floor (4) and extending to the rear of the vehicle.

Abstract: A temperature regulating material 31 for regulating a temperature of an exhaust manifold 11 is provided such that individual parts of the exhaust manifold 11 are uniformed in temperature. Heat transfer materials 31A with high thermal conductivity are layered as the temperature regulating material 31 on a cover member 25 at an area corresponding to a high-temperature area HT of the exhaust manifold 11. Heat shield materials 31B are layered as the temperature regulating material 31 on the cover member 25 at an area corresponding to the low-temperature area LT of the exhaust manifold 11. A heat dissipation material 31C as the temperature regulating material 31 coats an outer surface of the area of the cover member 25 corresponding to the high-temperature area of the exhaust manifold 11.

Abstract: An exhaust manifold and method of manufacturing the same is provided that includes at least one tube within shells of an exhaust manifold. The tube limits fluid communication from the tube into the shells of the exhaust manifold. An inlet flange is connectable to the exhaust manifold and is attachable to a cylinder head of a combustion engine. Exhaust gases expelled from the cylinder head are transmitted into the exhaust manifold. At least a portion of the exhaust gases pass through the tube. The exhaust manifold reduces NVH and cures emission control issues.

Abstract: An assembly in which a plurality of exhaust pipes in a multi-cylinder engine is fitted together in a single unit and in which exhaust gases do not create eddy currents or turbulence in the areas where the pipes are fitted together. The configuration is designed such that, to prevent pockets from forming between a skirt and a plurality of sockets formed in a perforated cap, parts of each of the sockets and part of the skirt are arranged linearly relative to each other so as not to form an eddy current.

Abstract: An exhaust manifold for an engine having at least one combustion chamber and multiple exhaust valves arranged on a first plane is provided with a housing formed to provide a longitudinally extending main exhaust gas passage on a second plane terminating in an outlet at one end. A plurality of discrete, laterally spaced, inlet branch passages include a floor and a ceiling which are initially level with the exhaust valve for a distance equal to one-half the width of the inlet branch passage prior to sloping downward toward the main exhaust gas passage. One of the inlet branch passages is positioned at an end of the housing opposite the exhaust gas passage outlet. The remaining inlet branch passages include integrally formed deflector members arranged to provide an angular change of flow direction requiring exhaust gas to enter the main exhaust gas passage in the downstream direction.

Abstract: A shielding component, in particular a heat shield, has at least two shield components (10, 12) which can be connected to each other by a connection unit (14). Because the connection unit (14) has a guide (16) which enables adjustment of the relative positions of the individual shield components (10, 12) to each other and which is used for fastening in the adjusted position. A sliding heat shield concept arises in which, with a heat shield having several shield components, adaptation is possible on site to the geometrical conditions of engines and their add-on parts including exhaust systems. Effective sound damping and heat insulation can be produced in a wide area with only one shielding component and its shield components.

Abstract: In a vehicle exhaust apparatus constituting an exhaust passage to an exhaust muffler from a plurality of exhaust pipes connected to a multi-cylinder engine, an expansion chamber is formed along the exhaust passage and is connected to an exhaust collector portion. The expansion chamber is formed so as to expand outward from the exhaust collector portion in a substantially arc or chevron shape when viewed from a direction substantially orthogonal to an exhaust gasflow. Preferably, the expansion chamber is formed in a spherical shape and plural branched exhaust pipes are formed on the exhaust gas downstream side of the expansion chamber.

Abstract: An exhaust gas system for an internal combustion engine, in particular a motor vehicle engine, is provided having, in one form, two cylinder banks arranged at an acute angle to one anther and each having at least one exhaust gas outlet, a so-called V-engine, having exhaust gas guide elements arranged in the region of the inner angle, including a housing surrounding the exhaust gas outlets of both cylinder banks in a gas tight manner and having at least one exhaust gas outlet opening is characterized in that the housing is made in two parts, with a first part which is connected to the one cylinder bank and surrounds its exhaust gas outlets and with a second part which is connected to the other cylinder bank and surrounds its exhaust gas outlets; in that the two parts each have a side facing the other part and having at least one housing opening via which the two parts communicate with one another; and in that an expansion compensation element is arranged between the two parts and surrounds the housing opening

Abstract: A secondary air supply system for an internal combustion engine includes: a cylinder head of the internal combustion engine having a plurality of exhaust holes and a plurality of supply holes formed thereon; a supply path communicating the exhaust holes and the supply holes so as to supply secondary air into the supply holes; an exhaust manifold attached to the cylinder head, and provided with a flange having a plurality of communication holes penetrating the flange; a lower shell including connection holes respectively corresponding to the communication holes, the lower shell being secured to the flange such that the communication holes and the connection holes are aligned; and an upper shell combined with the lower shell so as to form the supply path, communicated with the plurality of connection holes, between the lower shell and the upper shell.

Abstract: In an exhaust system, a first oxygen sensor is attached to an exhaust pipe connected to a standard cylinder in which the amount of injected fuel is the closest to the average of the amounts of fuel injected in a plurality of cylinders. A controller calculates the air-fuel ratio of the standard cylinder based on the value detected by the first oxygen sensor. Then, based on the difference between the calculated air-fuel ratio of the standard cylinder and a predetermined target air-fuel ratio, the amount of correction to the amount of fuel injected in the standard cylinder is determined such that the air-fuel ratio of the standard cylinder is equal to the target air-fuel ratio. Furthermore, based on the amount of correction to the amount of fuel injected in the standard cylinder, the amounts of correction of the other cylinders are determined.

Abstract: The present invention relates to an air-gap-insulated exhaust manifold (1) of an internal combustion engine, in particular in a motor vehicle, having a collecting line (2) that extends in a longitudinal direction (3), an outlet opening (4) oriented in the longitudinal direction (3), multiple inlet openings (5) oriented across the longitudinal direction (3) and a flange (6) that extends in the longitudinal direction (3) and includes the inlet openings (5), wherein an inside pipe (11) is situated in an outside pipe (10), forming an air-gap insulation, and whereby a gas-carrying outside pipe section (13) is provided in the area of at least one of the inlet openings (5) and leads from the respective inlet opening (5) to an assigned inside pipe inlet (14) which is at a distance from the flange (6). The inside pipe (11) is attached to the outside pipe (10) only in an attachment area (15).

Abstract: An intake and exhaust tuning system is disclosed. The exhaust system includes a collector slidably mounted within the exhaust fluid path and adjustable by an actuator to change the fluid path length between the collector and the exhaust ports of an engine. The intake tuning system includes a sliding member engaging parallel straight sections of tubes forming the intake system. The position of the sliding member is adjusted to change the length of the intake fluid path. Sealing members suitable for use in the intake and exhaust tuning systems are also disclosed.

Abstract: An exhaust system for an internal combustion engine having two banks of cylinders by which pulses of exhaust gas are alternately directed to a diverter subassembly. The diverter subassembly, which is located in the muffler, includes a perforated gas decelerator chamber which divides each pulse of exhaust gas between two exhaust outlets and causes a low pressure wave to occur in the exhaust system to enhance scavenging of a subsequent pulse of exhaust gas and thereby improve engine performance and mileage. The muffler further includes one or more cores and may or may not include a dead air space chamber to provide attenuation and tonal balance to the exiting exhaust gas.

Abstract: A structural component, especially a shielding part, has structural parts configured at least in part differently in terms of their superficial extension and/or the direction in which they extend. At least one structural part of a first type (10) is provided. Structural parts of a second type (34) are formed from the structural part of the first type (10) such that hollow section-like receiving channels (36) which are curved in at least two directions are molded into the structural part of the first type (10). The receiving channels (36) in one direction of curvature follow the curvature of the structural part of the first type (10). Thermal components, such as, for example, the curved exhaust lines of the exhaust system, can be accommodated in an integrating manner. Effective thermal shielding and noise insulation is ensured by overlapping.

Abstract: An exhaust system includes a first exhaust pipe group, a first catalyst device, and a second exhaust pipe group. A first coupling pipe of the first exhaust pipe group includes spaces in communication with respective first exhaust pipes. A second coupling pipe of the second exhaust pipe group includes spaces in communication with respective second exhaust pipes. The first exhaust pipe group and the second exhaust pipe group are joined such that the respective spaces are opposed to one another, with the first catalyst device interposed therebetween.

Abstract: This exhaust line element for a supercharged heat engine comprises an exhaust manifold (12) and a turbocompressor (14). The manifold (12) comprises at least two separate inlets (33) equipped with connection means at the outlet of the cylinders of the engine and a discharge outlet (21) for the exhaust gases which is common to the different inlets (33) and which is connected to the inlet tube (20) of the turbocompressor (14). It further comprises a bundle of internal tubes (42) which converge towards the outlet (21), each from an inlet (33) of the manifold, and an outer casing (40) inside which the bundle of tubes (42) extends. The inlet tube (20) and the outlet (21) of the manifold are connected by means of a peripheral weld seam (48) which is provided between the outer casing (40) and the inlet tube (20) of the turbocompressor (14), and the bundle of tubes (42) is left free from any welding to the inlet tube (20) of the turbocompressor (14) at the outlet (21) of the manifold (12).

Abstract: An improved exhaust system for a diesel engine and an improved overhead exhaust manifold segment therefore wherein the improvement comprises a plurality of catalytic converter elements removably positionable in the overhead exhaust manifold over the outlet ends of a series of exhaust port legs extending upwardly to the bottom of the overhead exhaust manifold from the cylinder exhaust ports.

Abstract: A heat shield for an internal combustion engine exhaust system for supporting a first heat shield plate and a second heat shield plate on a U-shaped exhaust pipe extending from an exhaust port of an engine, via a support member such as band members, and heat shield plate attachment fixtures. The first heat shield plate covers all around a curved section of the U-shaped exhaust pipe in the vicinity of the exhaust port. The second heat shield plate covers an upper part of a straight section of the U-shaped exhaust pipe and extends rearwardly from the curved section. Further, since the exhaust pipe is formed as one piece, the first heat shield plate may be formed as a simple two-part structure using the band members. With this configuration, an effective heat shielding effect can be exhibited, and cost can be reduced.

Abstract: A manifold for a multicylinder internal combustion engine which includes a plurality of outlets (1) comprises upper, lower and central shells (15, 5, 51) that are connected with one another and define inlet channels and outlet spaces (63, 65). A baffle plate (35) is attached to different shells (5, 15) by means of a fixed/movable bearing and can expand thermally without transferring thermal stresses to the shells (5, 15).

Abstract: An exhaust system has one or more exhaust tubes having a first diameter, interfaced to an exhaust manifold at one end and open at an opposite end for exhaust gas to escape, and a tubular extension of a second diameter, larger than the first diameter, joined to the open end of individual ones of the exhaust tubes, the extension cut at an angle with vertical and joined to the exhaust tube in a manner that exhaust gas expanding at the open end is free to expand upward, but expanding downward strikes the tubular extension, creating a downward force on the exhaust system.

Abstract: An exhaust manifold has a first upstream pipe connected to an exhaust ports of a group of cylinders of within an engine; a second upstream pipe connected to exhaust ports of cylinders other than the group of cylinders; and a merging pipe that merges the downstream ends of the first and second upstream pipe. The first upstream pipe is formed by a plurality of pipes and each pipe of the plurality of pipes forms a separate exhaust path that extends from the exhaust ports to the inside the merging pipe, and the second upstream pipe encloses the plurality of pipes and forms, between an inner surface of the second upstream pipe and an outer surface of the plurality of pipes, a plurality of exhaust paths that extend from the exhaust ports other than the exhaust ports of the group of cylinders to the inside of the merging pipe.

Abstract: A vehicle that sufficiently insulates heat between plural exhaust pipes connected to an engine. A cover member bridges over and covers the periphery of the exhaust pipes. A thermal insulation member fills in a space on a line connecting centers of the exhaust pipes, and a space in the vicinity of the line.

Abstract: A cooling system for a marine propulsion device provides a bypass loop around a cooling pump that allows the flow of cooling water through certain components to be reduced or increased as a function of the temperature of those components while causing a full flow of cooling water to flow through other selected heat emitting devices. Using this configuration of components and bypass conduits, the operating condition of the cooling water pump can be continually monitored, including the condition of its flexible vanes. By observing the effective cooling capacity of the system under conditions with the bypass valve open and closed, the effectiveness of the cooling water pump can be assessed and a suggestion of maintenance can be provided.

Abstract: The present invention generally relates to engines, and, more particularly, to an exhaust system for reducing buildup in an exhaust gas recirculation system when mixing hydrocarbons with exhaust.

Abstract: The invention relates to a double-walled exhaust manifold (10) for a motor vehicle, said exhaust manifold comprising at least one inner element (12) provided with sliding tubes (16, 18) which fit into each other, and an outer element (14) which is moulded from a single piece around the inner element (12) with which it determines an inner insulation cavity (20). The inventive exhaust manifold is characterised in that the inner element comprises at least one first straight upstream tube (22), a first end (24) of said tube being arranged in the extension of an exhaust line of an associated heat engine cylinder head and a second end (26) fitting together, in a sliding manners with an intermediate part (28) of at least one downstream tube (16, 18) having an axis (B) intersecting the axis (A) of the first tube (22).

Abstract: An exhaust system of an engine of a motorcycle, including an exhaust pipe configured to extend in one of an upward direction and a downward direction from an exhaust port formed at a front portion of a cylinder head of the engine and to then be bent to extend in an opposite direction to form a bent portion at a location in front of the engine.

Abstract: A vehicle exhaust system is provided that includes a first exhaust member having an end that includes an enlarged section. A second exhaust member is sized to receive a portion of the first exhaust member. The enlarged section of the first exhaust member has an outer diameter that is larger than an inner diameter of at least one section of the second exhaust member for creating an interference condition between the first and second exhaust member to prevent axial movement of the first exhaust member in at least one axial direction. The first exhaust member is secured to the second exhaust member by magnetic pulse welding.

Abstract: A watercraft can include an engine having a crankshaft with its output end extending rearward of a crankcase and a supercharger for compressing air feeding it to the engine. The supercharger can be located forward of a rear end of the crankcase. An exhaust pipe, designed to discharge combustion gas out of the watercraft, can be disposed above the supercharger. Forward of the supercharger, an intake box having an intake duct can be provided. An intercooler can be located beside the supercharger, through which the supercharger feeds the compressed air toward the engine.

Abstract: Disclosed is an exhaust system for discharging combusted gases from the cylinder of a vehicle engine, which comprises an exhaust manifold with a plurality of exhaust gas runners, wherein the exhaust gas runners are spaced so as to avoid an exhaust gas interference.

Abstract: A multi-piece exhaust manifold includes a ring seal between separate portions. The separate portions have generally cylindrical sealing surfaces formed thereon to mate with the ring seal. The ring seal may include a metal sheath filled with graphite or other sealing material.

Abstract: An exhaust manifold includes an open/close valve that switches between either closing or opening the exhaust path of a collection section, and switches the exhaust path of the exhaust gas between passing through or not passing through a bypass path containing an upstream catalyst. There is a partition wall structure in a pipe-mounting member so that when the valve is closed such that the exhaust gas during cold start is led to the upstream catalyst, the exhaust paths for each of the branch pipes on the upstream side of the valve inside a collection section are independent from one another. When the valve is closed, the downstream side of each of the branch pipes is not continuous inside the collection section, so the flow of air is prevented in this section, and exhaust interference and loss of exhaust heat are reduced.

Abstract: To provide an exhaust pipe structure in which the length of the exhaust pipe can be elongated while the total dimension is restricted. Provided is an exhaust pipe structure which includes an upstream-side exhaust pipe connected to exhaust ports of an engine. An exhaust chamber is provided which has an exhaust-gas inlet and an exhaust-gas outlet, and in which the upstream-side exhaust pipe is connected to the exhaust-gas inlet. In addition, the exhaust pipe structure includes a downstream-side exhaust pipe which is connected to the exhaust-gas outlet and which extends in such a direction as to move away from the exhaust ports. In the exhaust pipe structure, the exhaust-gas inlet is formed at a position farther away from the exhaust ports than the exhaust-gas outlet is positioned.

Abstract: An exhaust system has an exhaust tailpipe cover provided in an outlet region and, on the inside, contains inner exhaust pipes which are disposed spaced apart from the exhaust tailpipe cover by a passage. The passage in the exhaust tailpipe cover results in the exhaust tailpipe cover being exposed to as little thermal loading as possible and avoids transmitting heat to a surrounding vehicle rear part, in particular made of plastic.

Abstract: A motorcycle exhaust system includes a catalytic converter (43) disposed within an exhaust passage (37) for discharging exhaust gas (G) from a multi-cylinder combustion engine (E) and operable to purify the exhaust gas (G). An upstream end of the catalytic converter (43) has different regions (S1 and S2) communicated with upstream exhaust passage portions (37a and 37a), respectively, and a downstream end of the catalytic converter (43) is communicated with downstream exhaust passage portions (37b and 37b) in a number equal to or smaller than the number of the upstream exhaust passage portions (37a and 37a). Also, the catalytic converter (43) has a partition wall (43c) extending in a direction of flow of the exhaust gas (G) for allowing the exhaust gas (G) from the upstream exhaust passage portions (37a and 37a) to flow through the catalytic converter (43) without being mixed together.

Abstract: An outboard motor S has an exhaust manifold passage 37 for carrying exhaust gas from combustion chambers 30. The exhaust manifold passage 37 is formed in a part of a cylinder head 22 in an exhaust-side part of an internal combustion engine E on the side of the cylinder head 22 with respect to a joint surface P of a cylinder block 20 joined to the cylinder head 22. An exhaust passage 38 is formed in the cylinder block 20 and connected to the exhaust gas outlet 37e of the exhaust manifold passage 37 in the joint surface P. An electrical equipment box 50 holding electrical equipment is placed in the exhaust-side part so as to overlap the exhaust passage 38 when viewed in vertical direction. An electrical equipment box 50 is disposed adjacent to the cylinder head 22 with respect to the direction parallel to the axes of cylinders 20a.

Abstract: An exhaust pipe collecting structure for a multi-cylinder engine unit having multiple cylinders including a first exhaust pipe group and a second exhaust pipe group, each of which has two exhaust pipes selected from four exhaust pipes respectively connected to the four cylinders; a first exhaust sub-collecting pipe cast integrally with the first exhaust pipe group, a second exhaust sub-collecting pipe cast integrally with the second exhaust pipe group, a first joint portion located at a downstream end portion of the first exhaust sub-collecting pipe, and a second joint portion located at a downstream end portion of the second exhaust sub-collecting pipe.