VEHICLE

A vehicle includes an internal combustion engine; an engine body at least partially located at a center in a vehicle width direction; a first chamber provided in an exhaust passage extending from the engine body; and a second chamber provided downstream of the first chamber in the exhaust passage, in which the first chamber and the second chamber are each located behind the engine body, and at least a part of the first chamber and at least a part of the second chamber overlap the engine body in a vehicle width direction and a height direction, respectively. This vehicle structure can contribute to downsizing of an exhaust system of an internal combustion engine in a vehicle including a vehicle frequently used to travel on an uneven ground.

TECHNICAL FIELD

The present invention relates to a vehicle having three or more wheels including a front wheel and a rear wheel, and relates to a vehicle capable of traveling on an uneven ground such as a multi-utility vehicle (MUV) used even in a large inclined state, for example.

BACKGROUND ART

Patent Document 1 discloses an example of a vehicle that is called an all-terrain vehicle (ATV), a side-by-side vehicle, or the like and is frequently used on an uneven ground. The vehicle of Patent Document 1 has left and right front wheels and left and right rear wheels, and has left and right front seats and left and right rear seats. A dashboard is disposed in front of the front seats, and an area covered with the front cover in front of the dashboard is defined as a front area. An engine of an engine unit is disposed near a center of a vehicle body in a front-rear direction, and an intake duct connected to a cylinder portion of the engine is connected to an air cleaner. The intake duct includes a first pipe portion extending in the front-rear direction and a second pipe portion connected to a front portion of the first pipe portion and extending in the vertical direction, whereby the air cleaner is disposed in the front area. The air cleaner has an intake port for taking in outside air at an upper portion thereof, and the intake port is opened to the right. By opening the intake port in the direction orthogonal to the traveling direction of the vehicle in this manner, the possibility of drawing dust or the like from the intake port during traveling of the vehicle is reduced.

PRIOR ART DOCUMENT

Patent Document

Patent Document 1: JP 2020-108976 A

SUMMARY OF THE INVENTION

Underlying Problems to be Solved by the Invention

Meanwhile, in a vehicle capable of traveling on an uneven ground such as a multi-utility vehicle (MUV), for example, there is a demand for a more compact arrangement of an internal combustion engine in order to further widen a space for an occupant and the like. For example, an exhaust system of an internal combustion engine includes an exhaust gas purification device and a silencer, and further proposals of arrangement configurations of these exhaust system devices are expected.

An object of the present invention is to provide a novel arrangement that can contribute to downsizing of an exhaust system of an internal combustion engine in a vehicle including a vehicle frequently used on an uneven ground.

Means to Solve the Problems

In order to achieve the above object, one aspect of the present invention is a vehicle that has an internal combustion engine, the vehicle including:an engine body at least partially located at a center in a vehicle width direction;a first chamber provided in an exhaust passage extending from the engine body; anda second chamber provided downstream of the first chamber in the exhaust passage,in whichthe first chamber and the second chamber are each located behind the engine body, andat least a part of the first chamber and at least a part of the second chamber overlap the engine body in a vehicle width direction and a height direction, respectively.

With the above configuration, the arrangement area of the first chamber and the second chamber can be limited to the area behind the engine body and at least partially hidden by the engine body, and for example, it is possible to prevent the length of both or one of the exhaust pipe extending between the engine body and the first chamber and the exhaust pipe extending between the first chamber and the second chamber from becoming unnecessarily long, and thus it is possible to arrange the exhaust system of the internal combustion engine compactly.

Preferably, the first chamber is disposed to be biased to one side in the vehicle width direction, and the second chamber is disposed to be biased to the same side as the side where the first chamber is biased in the vehicle width direction. With this configuration, the first chamber and the second chamber can be biased in the same direction in the vehicle width direction, so that the chambers, which may generally have a large capacity, can be compactly disposed in the vehicle.

Preferably, a seat is provided in front of the engine body, a cargo bed is provided behind the engine body, and the first chamber and the second chamber are disposed below an upper end portion of a rear frame portion of a vehicle body frame, the upper end portion supporting the cargo bed. With this configuration, the exhaust system of the internal combustion engine can be disposed substantially compactly below the cargo bed. In addition, the exhaust gas of the internal combustion engine has a high temperature, and the exhaust system is likely to have a high temperature. By disposing the chambers under the cargo bed in this manner, it is possible to suppress the occupant sitting on the seat from being affected by the heat of the exhaust system.

Preferably, an exhaust pipe extending between the engine body and the first chamber and an exhaust pipe extending between the first chamber and the second chamber extend on the same side in the vehicle width direction. With this configuration, the exhaust pipe extending between the engine body and the first chamber and the exhaust pipe extending between the first chamber and the second chamber can be made compact in at least one of the length and the arrangement space.

Preferably, an exhaust pipe extending between the engine body and the first chamber has at least one joint portion, and an exhaust pipe extending between the first chamber and the second chamber has at least one joint portion. With this configuration, in the middle of each of the exhaust pipes, for example, a part of vibration transmitted from the engine body can be absorbed by the joint portions, whereby generation of abnormal noise from the exhaust system can be prevented and durability of the exhaust system component can be improved.

Preferably, joint portions of different types are provided in an exhaust pipe extending between the engine body and the first chamber and an exhaust pipe extending between the first chamber and the second chamber. With this configuration, the different types of joint portions can be provided and vibration transmitted from the engine body to each exhaust pipe is easily absorbed so that it is possible to prevent generation of abnormal noise and enhance durability of each exhaust system component.

Effects of the Invention

According to the above aspect of the present invention, since the above configuration is provided, the exhaust system of the internal combustion engine can be compactly disposed in the vehicle.

MODES FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment according to the present invention will be described with reference to the accompanying drawings. A same numeral is given to a same component (or configuration), and a name and a function thereof are the same. Therefore, detailed description thereof will not be repeated.

A vehicle10according to an embodiment will be described with reference toFIGS.1to9.FIG.1is a right side view of the vehicle10as viewed from the right side,FIG.2is a rear view of a part of a vehicle body frame (hereinafter, a frame)16and an internal combustion engine E as viewed from the rear of the vehicle without various cover members,FIG.3is a front view of a power unit P mounted on the vehicle10,FIG.4is a right side view of the power unit P,FIG.5is a right side view illustrating the power unit P mounted on the frame16,FIG.6is a top view illustrating a rear frame portion28of the frame16and an exhaust system of the internal combustion engine E in the vehicle10,FIG.7is a left side view illustrating the rear frame portion28of the frame16and the exhaust system of the internal combustion engine E in the vehicle10,FIG.8Ais a view illustrating an exhaust device ED of the exhaust system of the internal combustion engine E, and is a right side view of the exhaust device ED,FIG.8Bis a top view of the exhaust device ED, andFIG.9is a diagram illustrating an arrangement relationship between an engine body B of the internal combustion engine E and the chambers68and74of the exhaust device ED. In the following description and each drawing, the front-rear direction, the left-right direction, and the up-down direction are defined from the viewpoint of the driver who is in the vehicle10, a sign “FR” is used on the front side in the front-rear direction, a sign “LH” is used on the left side in the left-right direction, that is, the vehicle width direction, and a sign “UP” is used on the upper side in the up-down direction, that is, the height direction. The directions inFIGS.3,4,8A, and8Bconform to the arrangement when the power unit P or the exhaust device ED is mounted on the vehicle10.

The vehicle10includes the frame16serving as a framework of the vehicle10, a pair of left and right front wheels18supported at a front portion of the frame16, and a pair of left and right rear wheels20supported at a rear portion of the frame16. The vehicle10is a so-called rough terrain vehicle, and is a multi-utility vehicle (MUV) that travels by supplying a driving force to the front wheels18and the rear wheels20by the operation of the engine body B of the internal combustion engine E disposed in the vicinity of the center of the vehicle body in the front-rear direction and in the lower portion as illustrated inFIGS.2and5, for example. In the vehicle10, two occupants including a driver can sit on front seats22side by side in the vehicle width direction. A cargo bed24is provided on the rear side of the vehicle10. Note that the cargo bed24is an example of utilization of an accommodation portion25provided behind the seats22, and for example, a seat on which an occupant sits may be provided instead of the cargo bed24.

As illustrated inFIG.5, the frame16includes a center frame portion (main frame portion)26connected to the rear part of a front frame portion27, and a rear frame portion28connected to the rear part of the center frame portion26. The frame16includes a pair of left and right side frame portions attached to a side portions of the center frame portion26, and an upper frame portion32attached so as to extend upward from the front frame portion27, the side frame portion30, and the rear frame portion28. The front frame portion27supports the front wheels18via a front suspension. The rear frame portion28supports the rear wheels20via a rear suspension.

The upper frame portion32includes a pair of left and right front pillars34extending obliquely upward and rearward from the rear upper portion of the front frame portion27, a pair of left and right center pillars36extending upward from the central portion in the front-rear direction of the side frame portion30, and a pair of left and right rear pillars38extending upward from the rear end of the rear frame portion28. A cross pipe40is disposed between the left and right center pillars36, and the center pillars36are connected to each other by the cross pipe40. The cross pipe40is a frame member made of a roll bar, that is, a roll bar frame portion, and is an example of a reinforcing frame portion. A space surrounded by the front frame portion27, the side frame portion30, the center pillar36, and the upper frame portion32forms a cabin42in which occupants ride. As illustrated inFIG.1, the seats22are disposed in the cabin42.

In the cabin42, the seats22are disposed between the front pillar34and the center pillar36, and a pair of left and right front doors44opened and closed by a hinge mechanism on the front side is provided. Also inFIG.5, the seats22are indicated by a broken line. In addition, a rear cover45is provided so as to partition immediately behind the seats22of the cabin42, that is, the rear of the cabin42.

The rear cover45is positioned immediately behind the cross pipe40in the front-rear direction, and extends in a planar shape in the vehicle width direction and the vertical direction. The above-described cargo bed24is provided on the rear side of the rear cover45. The cargo bed24includes a hinge mechanism on the rear side, and is configured to be able to rise upward around the hinge mechanism.

In the vehicle10, the power unit P is mounted on the frame16. The power unit P includes a water-cooled four-stroke cycle internal combustion engine E having two parallel cylinders and a transmission having a transmission shaft parallel to a crankshaft (FIG.9illustrates a crankshaft axis47.) thereof. The driving force of the internal combustion engine E is transmitted to the front wheels18and the rear wheels20via the transmission as described above. According to the present embodiment, the internal combustion engine E, that is, the engine body B thereof is disposed on the frame16of the vehicle10such that the crankshaft, that is, the crankshaft axis47extends in the vehicle front-rear direction, but the present invention does not limit the arrangement of the engine body B to this manner.

The engine body B of the internal combustion engine E is disposed substantially at the center in the front-rear direction. As is clear fromFIGS.1to5, the engine body B is positioned behind the seats22on which an occupant such as a driver sits. The engine body B of the internal combustion engine E is provided at a position of the center frame portion26, that is, at a position of the center pillar36in the front-rear direction, and at least a part of the engine body B overlaps the center pillar36in a side view (seeFIG.5). As illustrated inFIG.2, when defining a center plane CF that passes through substantially the center of the vehicle10in the vehicle width direction, is orthogonal to the vehicle width direction, extends in the front-rear direction, and extends in the vertical direction, the center plane CF intersects with a cylinder head48of the engine body B of the internal combustion engine E. In other words, in the vehicle10, at least a part of the engine body B is located behind the seat22on which the driver sits and at the center in the vehicle width direction. As illustrated inFIG.2, the engine body B of the internal combustion engine E is vertically disposed such that a cylinder axis C of a cylinder bore of a cylinder block46is inclined rightward in the vehicle width direction but is substantially straight in the vehicle front-rear direction.

The engine body B includes the cylinder block46in which the cylinder bore is formed in an upper portion of a crankcase that pivotally supports the crankshaft, and the cylinder head48and a cylinder head cover50are sequentially stacked above the cylinder block46. An intake system including air cleaners12and14, which is an intake device ID, extends above the engine body B, and an exhaust system, that is, an exhaust device ED extends behind the engine body B. The engine body B is provided with its cylinder axis C inclined as described above, and the intake device ID is connected to the upper left portion of the cylinder head48, and the exhaust device ED is connected to the lower right portion of the cylinder head48.

In the intake device ID connected to the engine body B of the internal combustion engine E, the air cleaner12disposed relatively downstream (downstream in the intake flow direction) in the intake passage52connected to the engine body B is referred to as a first air cleaner, and the air cleaner14disposed upstream of the first air cleaner12is referred to as a second air cleaner. In this example, the first air cleaner12is larger than the second air cleaner14, and the first air cleaner12may be simply referred to as an air cleaner, and the second air cleaner14may be referred to as a prefilter.

In the intake passage52, an intake port of the cylinder head48, a throttle body54, the first air cleaner12, and the second air cleaner14are positioned in order from the downstream side to the upstream side in the intake flow direction, and a part of the intake passage52is defined and formed by each of them. The throttle body54and the first air cleaner12are connected by first intake pipes56which are intake pipe members, the first air cleaner12and the second air cleaner14are connected by a second intake pipe58, and the second air cleaner14has an air intake14afor taking in outside air.

The first air cleaner12and the second air cleaner14may be mechanically and directly connected to each other, or may be integrally formed from the beginning. In a case where the first air cleaner12and the second air cleaner14are integrally formed from the beginning, the number of components can be reduced and the component cost can be reduced.

According to the present embodiment, the engine body B includes two cylinders, and includes the first intake pipes56for each cylinder as illustrated inFIGS.3and4. In other words, each of the two first intake pipes56is connected to the first air cleaner12. The first intake pipe56includes a bellows-shaped pipe portion56bhaving a bellows structure, but may not have a bellows structure. The second intake pipe58, which is an intake pipe member connecting the first air cleaner12and the second air cleaner14, may also include a bellows-shaped pipe portion.

The first intake pipe56connected to the upper left side of the cylinder head48of the engine body B extend upward and are connected to the first air cleaner12positioned above, here, directly above the engine body B. The first air cleaner12includes a dirty side12alocated on the upstream side in the intake flow direction and a clean side12blocated on the downstream side in the intake flow direction, and the dirty side12aand the clean side12bare partitioned by an air cleaner element12c. In the first air cleaner12, the dirty side12ais located on the outer periphery and the lower side of the substantially cylindrical air cleaner element12c. In particular, here, as illustrated inFIGS.2and3, the air cleaner element12cis provided so that the dirty side12aspreads on the lower side of the air cleaner element12c. The clean side12bis located on the left side of the air cleaner element12c. The clean side12bextends downward to the left side of the dirty side12a. Accordingly, the first air cleaner12is disposed such that the dirty side12aand the clean side12bare arranged side by side in the vehicle width direction. Upstream ends56aof the first intake pipes56are inserted into the clean side12bof the first air cleaner12from the lower side to the upper side (seeFIG.3, for example).

The second air cleaner14is disposed on the right side of the first air cleaner12. The second intake pipe58connected to the downstream side of the second air cleaner14extends inward in the vehicle width direction and is connected to the first air cleaner12. Here, a downstream end58aof the second intake pipe58is inserted into the dirty side12aof the first air cleaner12. The second intake pipe58extends between and connects the first air cleaner12and the second air cleaner14while being slightly inclined in the vertical direction and the front-rear direction. As illustrated inFIGS.2and3, the second air cleaner14is disposed at a position slightly higher than the first air cleaner12. As illustrated inFIGS.2and5, the second air cleaner14is disposed immediately behind the right-side center pillar36and at a position not reaching the outside of the center pillar36, and is positioned inside the frame16. The second air cleaner14may be fixed to the center pillar36using a connecting member or the like, for example.

The second air cleaner14is a box-shaped member, defines and forms a passage expansion portion in the intake passage52, and has a cross-sectional area larger than the flow path cross-sectional area of the air intake14aand the flow path cross-sectional area of a downstream connection portion14bthat is a connection portion with the second intake pipe58. Therefore, the second air cleaner14can exhibit a function of separating sand, dust, and the like contained in the intake air flowing into the second air cleaner. The second air cleaner14may include an air cleaner element.

As illustrated inFIG.2, the center plane CF intersects with the first air cleaner12. Accordingly, at least a part of the first air cleaner12is located at the center in the vehicle width direction. As described above, the first air cleaner12is located above the engine body B of the internal combustion engine E. In addition, the first air cleaner12is located below the cross pipe40, here, directly below the cross pipe40. As apparent fromFIGS.2and5, at least a part of the first air cleaner12overlaps the cross pipe40as a reinforcing frame portion in the vehicle front-rear direction.

The second air cleaner14is located on the side of the first air cleaner12, and is arranged side by side on the right side in this example. Since the center plane CF intersects with the first air cleaner12, the second air cleaner14is positioned outside the first air cleaner12in the vehicle width direction.

However, the second air cleaner14is disposed inside the frame16, particularly inside the center pillar36of the upper frame portion32constituting the outer frame of the vehicle10in the frame16. As apparent fromFIG.2, the second air cleaner14is disposed outside the engine body B in the vehicle width direction. Since the second air cleaner14is disposed on the right side of the first air cleaner12as described above, at least a part of the second air cleaner14, particularly most of the second air cleaner14overlaps with the first air cleaner12in the vehicle front-rear direction (seeFIG.5).

Next, the exhaust device ED connected to the engine body B of the internal combustion engine E will be described. As illustrated inFIG.4, the exhaust device ED includes a chamber (hereinafter, a first chamber)68provided in an exhaust passage64extending from the engine body B, and a chamber (hereinafter, a second chamber)74provided on the downstream side of the first chamber68in the exhaust passage64. Each of the first chamber68and the second chamber74defines and forms a part of the exhaust passage64, and the same applies to an exhaust pipe66and the like described later. Here, the first chamber68includes a catalyst and is configured to function as an emission control device, and the second chamber74on the downstream side of the first chamber68in the exhaust flow direction is configured to function as a silencer, that is, a muffler. However, the number of chambers provided in the exhaust device ED, the use thereof, and the configuration thereof are not limited thereto.

As described above, the engine body B has two cylinders, and as illustrated inFIGS.3and4, the exhaust pipe66connected to the engine body B has two upstream connection portions66acorresponding to the cylinders of the engine body B. The exhaust pipe66includes the two upstream connection portions66aeach of which is a branch pipe portion66b, and one downstream connection portion66dwhich is a downstream common pipe portion66cwhere the branch pipe portion66bmerges. The exhaust pipe66is connected to the first chamber68.

As illustrated inFIGS.8A and8B, the first chamber68has an upstream connection portion68aand a downstream connection portion68b. The first chamber68includes a tank68chaving a cylindrical shape with both ends closed, and further includes the upstream connection portion68aand the downstream connection portion68bon one end surface68dside of the tank68c. The upstream connection portion68ais a pipe portion extending from the end surface68dof the tank68csubstantially parallel to the central axis68xof the first chamber68. The upstream connection portion68ais connected to the downstream connection portion66dof the downstream common pipe portion66cof the exhaust pipe66by using a joint (hereinafter, a first joint)70. Here, the first joint70is a flex joint. On the other hand, the downstream connection portion68bis a pipe portion which extends from the end surface68dof the tank68csubstantially parallel to the central axis68xof the first chamber68, is bent in a direction substantially opposite to the upstream connection portion68a, and extends in a direction substantially orthogonal to the central axis68x. The downstream connection portion68bis connected to an upstream connection portion74aof the second chamber74, which is a chamber different from the first chamber68, by using a joint (hereinafter, a second joint)72. Since the second joint72is not a flex joint but is a joint of a type different from that of the first joint70, a joint portion70jformed by the first joint70and a joint portion72jformed by the second joint72are joint portions of different types.

The second chamber74includes a tank74bhaving a cylindrical shape with both ends closed, and further includes the upstream connection portion74aand an exhaust outlet portion74e. The upstream connection portion74adescribed above is a pipe portion that extends from one end surface74cof the tank74bsubstantially parallel to the central axis74xof the tank74b, bends, and extends in a direction substantially orthogonal to the central axis74x. The exhaust outlet portion74eis a pipe extending from other end surface74dof tank74bof the second chamber74. As described above, the upstream connection portion74ais connected to the downstream connection portion68bof the first chamber68by using the second joint72.

The exhaust pipe66connected to the lower right portion side of the cylinder head48of the engine body B extends downward, bends, and extends rearward. Then, the exhaust pipe66is connected to the first chamber68located below the cylinder head48from the front lower side (seeFIGS.2and4). As illustrated inFIGS.8A and8B, on the end surface68dof the first chamber68, the downstream connection portion68bextends from a position obliquely upward and rearward with respect to the upstream connection portion68a, bends, and extends rearward. Here, since the tank74bof the second chamber74has substantially the same shape and dimension as those of the tank68cof the first chamber68and is located slightly above the tank68c, the downstream connection portion68bis slightly inclined so as to be located higher toward the downstream side thereof and extends rearward, and is connected to the upstream connection portion74aof the second chamber74. The upstream connection portion74aextends from the upper portion of the end surface74cof the second chamber74, extends forward with a slight inclination so as to be positioned downward toward the upstream side, and is connected to the downstream connection portion68bof the first chamber68. As illustrated inFIGS.2and8A, the exhaust outlet portion74eextending from the end surface74dat an opposite side of the end surface74cof the second chamber74extends so as to open obliquely downward and rearward.

Here,FIG.9is referred.FIG.9is a rear view of the portion of the engine body B of the internal combustion engine E mounted on the vehicle10as viewed from the rear side in the vehicle front-rear direction, and is a view illustrating an outline68oof the first chamber68and an outline74oof the second chamber74in the vehicle10in an overlapping manner with the internal combustion engine E.FIG.9further illustrates a predetermined area PA defined behind the engine body B in the vehicle front-rear direction. The predetermined area PA is an area defined by a width W in the vehicle width direction and a width H in the height direction of the engine body B. In particular, inFIG.9, the predetermined area PA is a quadrangular area including an outer surface50aof the cylinder head cover50and an area (accommodation area)47sof an accommodation portion that accommodates the outline of the accommodation portion of the crankshaft, that is, the rotating crankshaft in the crankcase, and having four sides extending in the vehicle width direction and the height direction. As is clear fromFIG.9, the outline68oof the first chamber68and the outline74oof the second chamber74partially overlap the predetermined area PA. In particular, the crankshaft axis47is located within the outline68oof the first chamber68, and the crankshaft axis47is located within the outline74oof the second chamber74. Therefore, with respect to the first chamber68and the second chamber74located behind the engine body B, at least a part of the first chamber68overlaps the engine body B in the vehicle width direction and the height direction, and at least a part of the second chamber74also overlaps the engine body B in the vehicle width direction and the height direction.

Here,FIG.6is referred.FIG.6is a top view around the rear frame portion28, and illustrates a part of the exhaust device ED.FIG.6illustrates the above-described center plane CF that passes through substantially the center of the vehicle10in the vehicle width direction, is orthogonal to the vehicle width direction, extends in the front-rear direction, and extends in the vertical direction.

As is clear fromFIG.6, both the first chamber68and the second chamber74are biased to one side of the center plane CF, the left side in this example. In other words, the first chamber68, particularly the tank68cthereof, is disposed to be biased to one side in the vehicle width direction, and the second chamber74, particularly the tank74bthereof, is disposed to be biased to the same side as the side on which the first chamber68is biased, that is the left side in this example, in the vehicle width direction.

Further, as is apparent fromFIG.6, an exhaust pipe (hereinafter, a first exhaust pipe)67aformed by connecting the exhaust pipe, that is, the exhaust pipe66and the upstream connection portion68aextending between the engine body B and the first chamber68, particularly the tank68cthereof, and an exhaust pipe (hereinafter, a second exhaust pipe)67bformed by connecting the exhaust pipe, that is, the downstream connection portion68band the upstream connection portion74aextending between the first chamber68, particularly the tank68cthereof, and the second chamber74, particularly the tank74bthereof, extend on the same side in the vehicle width direction. In this example, the first exhaust pipe67aand the second exhaust pipe67bextend in the right side of the center plane CF.

As illustrated inFIG.7, the rear frame portion28includes an upper rear frame portion28uon the upper side and a lower rear frame portion28don the lower side, and includes a support frame portion28sextending in the vertical direction, that is, the height direction, and connecting the upper rear frame portion28uand the lower rear frame portion28d. Regarding the rear frame portion28, the first chamber68and the second chamber74are disposed in the rear frame portion28. In other words, the first chamber68and the second chamber74are disposed below the upper end portion of the rear frame portion28, that is, below the upper rear frame portion28u. The first chamber68and the second chamber74are disposed above the lower end of rear frame portion28, that is, above the lower rear frame portion28d. The cargo bed24is provided at the upper end portion of the rear frame portion28, that is, above the upper rear frame portion28u.

According to the vehicle10having the above configuration, the following functions and effects are achieved.

In the vehicle10, at least a part of the engine body B of the internal combustion engine E is positioned at the center in the vehicle width direction, the first chamber68is provided in the exhaust passage64extending from the engine body B, and the second chamber74is provided on the downstream side of the first chamber68in the exhaust passage64. The first chamber68and the second chamber74are positioned behind the engine body B, and at least a part of the first chamber68and at least a part of the second chamber74overlap the engine body B in the vehicle width direction and the height direction, respectively. According to this configuration, the arrangement area of the first chamber68and the second chamber74can be limited to an area behind the engine body B and at least partially hidden by the engine body B. With this configuration, here, it is possible to prevent the lengths of both the first exhaust pipe67aextending between the engine body B and the first chamber68and the second exhaust pipe67bextending between the first chamber68and the second chamber74from becoming unnecessarily long, and thus, it is possible to make the exhaust system of the internal combustion engine E compact. In this manner, the vehicle10can provide a novel arrangement that can contribute to the downsizing of the exhaust system of the internal combustion engine E in the vehicle10that is frequently used on an uneven ground.

In addition, the first chamber68is disposed to be biased to one side in the vehicle width direction, and the second chamber74is disposed to be biased to the same side as the side on which the first chamber68is biased in the vehicle width direction. Therefore, the first chamber68and the second chamber74can be biased in the same direction in the vehicle width direction, so that the chambers68and74can be compactly disposed in the vehicle10.

Further, the first exhaust pipe67aextending between the engine body B and the first chamber68and the second exhaust pipe67bextending between the first chamber68and the second chamber74extend on the same side in the vehicle width direction. Therefore, here, the first exhaust pipe67aand the second exhaust pipe67bcan be made compact both in length and arrangement space.

Further, the first chamber68and the second chamber74are disposed below the upper rear frame portion28uwhich is the upper end portion of the rear frame portion28of the vehicle body frame16supporting the cargo bed24provided on the rear side of the seat22with the engine body B substantially interposed therebetween. As a result, the exhaust system of the internal combustion engine E can be disposed substantially compactly below the cargo bed24.

In addition, the exhaust gas of the internal combustion engine E has a high temperature, and the exhaust system is likely to have a high temperature. By disposing the chambers68and74under the cargo bed24in this manner, it is possible to suppress the occupant sitting on the seat22from being affected by the heat of the exhaust system.

In the internal combustion engine E of the vehicle10, the joint portion70jformed by the first joint70is provided in the first exhaust pipe67aextending between the engine body B and the first chamber68, and the joint portion72jformed by the second joint72is provided in the second exhaust pipe67bextending between the first chamber68and the second chamber74. According to this configuration, in the middle of each of the exhaust pipes67aand67b, for example, a part of vibration transmitted from the engine body can be absorbed by the joint portions70jand72j, whereby generation of abnormal noise from the exhaust system can be prevented and durability of the exhaust system component can be improved.

Further, the first exhaust pipe67aextending between the engine body B and the first chamber68and the second exhaust pipe67bextending between the first chamber68and the second chamber74have joint portions70jand72jof different types. According to this configuration, the different types of joint portions70jand72jfurther easily absorb vibration transmitted from the engine body to each exhaust pipe, and thus, it is possible to prevent generation of abnormal noise and enhance durability of each exhaust system component.

Although the vehicle10having the above configuration has been described above, the present invention is not limited to the above description. For example, in the exhaust device ED of the internal combustion engine E of the vehicle10, the first chamber68, and the second chamber74are disposed such that the axes68xand74xextend in parallel in the vehicle width direction. However, at least one of the chambers, more specifically, the axis extending in the longitudinal direction of at least one of the chambers may be inclined with respect to the vehicle width direction.FIG.10illustrates a modification of the exhaust device having a configuration in which the axis68xextending in the longitudinal direction of the first chamber68is parallel to the vehicle width direction (corresponding to the LH direction), and the axis74xextending in the longitudinal direction of the second chamber74is inclined with respect to the vehicle width direction. Further, in the exhaust device ED of the internal combustion engine E of the vehicle10, the first exhaust pipe67aextending between the engine body B and the first chamber68and the second exhaust pipe67bconnecting the first chamber68and the second chamber74are provided on the same side in the vehicle width direction. However, these exhaust pipes67aand67bmay be disposed on different sides.FIG.11illustrates an example of an exhaust device having a configuration in which the exhaust pipes67aand67bare disposed on different sides in the vehicle width direction.

As described above, in the internal combustion engine E of the vehicle10, the first joint70that is a flex joint is used as the joint portion70jof the first exhaust pipe67aextending between the engine body B and the first chamber68. In the first joint70, since the flex joint is used for both the connection targets, vibration can be further absorbed, so that the strength of the pipe to which the joint is connected can be increased. However, in the case of using a flex joint, since parts such as bolts for fixing the joint are required and the number of parts increases, one may be a flex joint and the other joint may be an insertion type (fitting type) normal joint other than the flex joint. In this case, the number of parts can be reduced. Note that the present disclosure does not exclude the use of the same type and the same combination of joints for the first joint70and the second joint72.

The embodiment of the present invention and the modified example thereof have been described above, but the present invention is not limited thereto. Various substitutions and changes may be made without departing from the spirit and scope of the present invention as defined by the claims of the present application. The processing and means described in the present disclosure can be freely combined and implemented as long as no technical contradiction occurs.

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