WO2023189437A1

WO2023189437A1 - Intake structure of internal combustion engine in saddle-type vehicle

Info

Publication number: WO2023189437A1
Application number: PCT/JP2023/009409
Authority: WO
Inventors: 賢上田; 啓登千葉; 裕行佐々木; 裕幸新村
Original assignee: 本田技研工業株式会社
Priority date: 2022-03-31
Filing date: 2023-03-10
Publication date: 2023-10-05

Abstract

The present disclosure is intended to provide a saddle-type vehicle wherein it is possible to secure a sufficient amount of intake air to an internal combustion engine while sufficiently preventing water, dust, etc., from entering an intake duct. An intake structure IS of an internal combustion engine in a saddle-type vehicle according to one embodiment is provided to an intake duct 54 upstream of an air cleaner 52 of the internal combustion engine 32, and the intake structure comprises a partition W that separates an upstream intake passage 80 and a downstream intake passage 84 that connects to the downstream side of the upstream intake passage and has a flow direction different from that of the upstream intake passage, and a concave curved portion 88 extending from the upstream intake passage side toward the downstream intake passage side.

Description

Intake structure of internal combustion engine in saddle type vehicle

The present invention relates to an intake structure for an internal combustion engine in a straddle-type vehicle.

Conventionally, some straddle-type vehicles equipped with an internal combustion engine as a power source are arranged so that the intake pipe of the internal combustion engine extends toward the rear of the vehicle body. An air cleaner is provided in the intake pipe, and an intake duct for taking in outside air is provided upstream of the air cleaner.

Patent Document 1 discloses an example of a straddle-type vehicle equipped with an internal combustion engine having such an intake pipe arrangement. In the motorcycle, which is a straddle-type vehicle disclosed in Patent Document 1, the intake duct extends to the rear of the vehicle body from the axis of the rear cushion, and has an opening for the intake duct behind the rear cushion. . With this configuration, the volume of the air cleaner can be ensured, and the intake duct behind the air cleaner can be lengthened.

Furthermore, in the straddle-type vehicle described in Patent Document 1, the intake duct has a duct case to which the upstream end of the intake duct body extending to the air cleaner is connected, and an opening facing upward of the duct case. The duct case cover is attached to the duct case so as to cover the opening and the flow path forming portion extending inward in the vehicle width direction from the opening. The intake duct configured in this manner includes a first flow path having an opening that opens downward on the inside in the vehicle width direction, and a second flow path that takes outside air into the duct case from the gap between the duct case cover and the rear carrier. A road is formed. By forming the second flow path in addition to the first flow path, it is possible to ensure a sufficient amount of intake air.

Japanese Patent Application Publication No. 2021-66294

In the straddle-type vehicle described in Patent Document 1, in order to prevent water, dust, etc. from entering the intake duct, a labyrinth structure meandering in the vertical direction is formed in the first flow path, and a labyrinth structure is formed in the first flow path to ensure the amount of intake air. In addition to the first channel, a second channel was formed. However, although the second flow path is covered by the top plate of the rear carrier, the second flow path opens upward and extends vertically toward the duct case, so there is a possibility of rain entering. Ta.

An object of the present invention is to provide a configuration for a straddle-type vehicle that can sufficiently prevent water, dust, etc. from entering the intake duct while ensuring a sufficient amount of intake air to the internal combustion engine. It is about providing.

In order to achieve the above object, one aspect of the present invention is to
An intake structure for an internal combustion engine in a straddle-type vehicle,
A downstream side that is provided in an intake duct upstream of the air cleaner of the internal combustion engine, is connected to an upstream intake passage, and is connected to the downstream side of the upstream intake passage, and has a flow direction different from the flow direction of the upstream intake passage. a partition separating the intake passage from the intake passage;
The present invention provides an intake structure characterized by comprising a concave curved portion extending from the upstream intake passage side toward the downstream intake passage side.

According to the intake structure configured as described above, the upstream intake passage is separated from the downstream intake passage whose flow direction is different from the flow direction of the upstream intake passage by the partition provided in the intake duct. Intrusion of water, dust, etc. into the duct can be suitably prevented. Further, since the concave curved portion is provided, the flow of intake air from the upstream side intake passage side to the downstream side intake passage side can be made smooth, and therefore a sufficient amount of intake air can be ensured.

Preferably, the upstream intake passage opens toward the lower side of the vehicle body. With this configuration, it is possible to more reliably prevent water, dust, and other dust from entering the intake duct through the opening.

Preferably, the concave curved portion is provided so as to extend to a boundary portion connecting the upstream intake passage and the downstream intake passage. With this configuration, the flow of intake air from the upstream intake passage side to the downstream intake passage side can be made smoother, and therefore, the intake performance to the internal combustion engine can be improved.

Preferably, a protrusion that protrudes into the upstream intake passage is further provided. This protrusion can prevent mud, dust, etc. from entering the intake duct. Particularly, when the upstream intake passage opens toward the lower side of the vehicle body, it is possible to better prevent mud, dust, etc. from entering the intake duct from below the vehicle body.

Preferably, the protrusion is provided on the partition. With this configuration, it is possible to suppress an increase in the number of parts constituting the intake duct.

Preferably, the intake duct further includes a second partition that at least partially defines a space having an open end connected to the downstream intake passage and a closed end opposite to the open end. With this configuration, intake pulsation can be suppressed. This configuration may also provide a sound deadening effect.

Preferably, the opening at the upstream end of the upstream intake passage is above a rear cushion disposed on the side of the rear wheel of the straddle-type vehicle, and is located above the axis of the rear cushion of the vehicle body. It is located at the rear. By locating the opening at the upstream end of the upstream intake passage at such a position, the intake duct can be extended to the rear of the rear cushion, thereby ensuring a long length of the intake duct.

Preferably, the intake duct is located below the vehicle body of the rear carrier of the saddle type vehicle. Thereby, intake noise transmitted to the driver from the opening of the intake duct can be suppressed.
Furthermore, although the area below the rear carrier tends to become a dead space, by arranging the intake duct there, the space can be used effectively.

Preferably, the straddle-type vehicle has a fuel tank below the vehicle body of the seat, and the air cleaner is disposed on the lower side of the fuel tank, and the air cleaner is larger than the width of the seat in the vehicle width direction. The width of the fuel tank in the vehicle width direction is small, and the intake passage is arranged such that the opening at the upstream end of the upstream intake passage opens at the rear of the vehicle in a recessed space defined between the seat, the fuel tank, and the air cleaner. Ducts are provided. With this configuration, the concave space can be used as a travel wind guide, the travel wind can be directed toward the intake duct efficiently, and the outside air can be taken in through the opening of the intake duct.

Preferably, the intake duct includes a duct case to which an upstream end of the intake duct body extending to the air cleaner is connected, and a duct case cover attached above the vehicle body of the duct case. With this configuration, it becomes possible to more easily create an upstream intake passage and a downstream intake passage connected thereto in the intake duct.

Preferably, the concave curved portion is provided on the duct case cover. Thereby, an increase in the number of parts of the intake duct can be suppressed.

Preferably, the partition portion is provided in the duct case. Thereby, an increase in the number of parts of the intake duct can be suppressed.

According to the above-mentioned aspect of the present invention, since the above-mentioned configuration is provided, it is possible to sufficiently prevent water, dust, etc. from entering the intake duct in a straddle-type vehicle, and to provide a sufficient amount of intake air to the internal combustion engine. It becomes possible to secure the

FIG. 1 is a right side view of the left side of a motorcycle, which is a straddle-type vehicle, according to an embodiment of the present invention. FIG. 2 is a sectional view of the motorcycle shown in FIG. 1 taken along line II-II in FIG. 1 at the position of the intake duct. 3 is a perspective view of a portion of the motorcycle of FIG. 1 in the cross section of FIG. 2; FIG. FIG. 4 is a perspective view of a partial cross section of the intake duct mounted on the motorcycle of FIG. 1, and is a view of the intake duct cut along the line IV-IV of FIG. 2 as viewed diagonally from below. . FIG. 5 is a view of the vicinity of the intake duct in the motorcycle shown in FIG. 1 viewed from above, and is a partially transparent view. FIG. 6 is a view of the vicinity of the intake duct in the motorcycle shown in FIG. 1, viewed from below. FIG. 7 is a diagram showing the inside of the duct case cover of the intake duct from FIG. 6, with the duct case omitted. FIG. 8 is a sectional view of the intake duct and its surroundings, taken at a different position from FIG. 2, of the motorcycle shown in FIG. 1, and is a view viewed from an angle. FIG. 9 is a view of the surroundings of the intake duct of the motorcycle shown in FIG. 1, with the duct case cover omitted, as viewed from inside the vehicle body. FIG. 10 is a view of the upper side of the rear portion of the motorcycle shown in FIG. 1 cut in the middle in the front-rear direction as seen from the front.

Hereinafter, embodiments according to the present invention will be described based on the accompanying drawings.

FIG. 1 is a right side view of the left side of a motorcycle 10, which is a straddle-type vehicle equipped with an intake structure IS according to an embodiment of the present invention. In this embodiment, the front-rear, left-right, and up-down directions of the motorcycle 10 will be described based on the direction seen from the driver seated on the seat 12 of the motorcycle 10. In the figure, the symbol "FR" indicates the front, the symbol "RR" indicates the rear, the symbol "UP" indicates the upper side, the symbol "DW" indicates the lower side, the symbol "LH" indicates the left side, and the symbol "RH" indicates right side.

The motorcycle 10 has a vehicle body 14 (vehicle body frame). The vehicle body 14 includes a head pipe 16, a down frame 18 extending diagonally backward and downward from the head pipe 16, a pivot plate 29 extending downward from the lower end of the down frame 18, and a pair of swings extending rearward from the pivot plate 29. It includes an arm 20 and a rear frame 22 extending upward and rearward from the rear end of the down frame 18.

The head pipe 16 supports the front fork 24 in a steerable manner. A bar handle 26 is attached to the upper part of the head pipe 16 and is operated by the driver. A front wheel 28 is rotatably supported at the lower end of the front fork 24. A pivot plate 29 and an engine hanger (not shown) are joined to the down frame 18, and an internal combustion engine (hereinafter referred to as engine) 32 is joined to the pivot plate 29 and the engine hanger. Further, a swing arm 20 is rotatably attached to the pivot plate 29.
Further, an engine cover 30 is provided between the lower end of the pivot plate 29 and the down frame 18 to cover the front and lower part of the engine 32. The engine cover 30 is provided with a step 34 on which the driver rests his or her feet.

The rear frame 22 supports the seat 12, the fuel tank 36 under the seat 12, the rear carrier 38 behind the seat 12, and the like. The down frame 18 and the rear frame 22 are covered with a resin vehicle body cover 40.

A rear wheel 42 is rotatably supported at the rear end of the swing arm 20. Further, a lower end portion of a rear cushion 44 is joined near the rear end portion of the swing arm 20. The rear cushion 44 extends diagonally forward and upward from the swing arm 20 and is joined to the rear frame 22. As shown in FIG. 1, the rear cushion 44 is arranged at a position overlapping the rear wheel 42 when viewed from the side. Although not particularly illustrated, a pair of rear cushions 44 are provided on the left and right sides of the vehicle body 14, and they are also provided at the same position on the right side surface.

The engine 32 is installed substantially horizontally on the vehicle body, and the head cover, cylinder head, cylinder block, and crankcase are arranged in a row from the front to the rear of the vehicle. An intake device 46 is provided above the intake port arranged in the cylinder head of the engine 32. The intake device 46 here includes an inlet pipe, a throttle body, a fuel supply device (for example, an injector), and the like. An intake pipe line 48 that takes air into the engine 32 is connected to the intake device 46 on the left side of the motorcycle 10. The intake pipe line 48 is arranged to extend toward the rear of the vehicle from a connection portion of the engine 32 to the intake device 46. Here, the intake pipe 48 extends toward the rear of the vehicle through the left side, which is one side of the vehicle body 14, and is connected to an intake duct 54 provided on the rear side of the axis C of the rear cushion 44. Outside air is taken in through the opening 82 (see FIG. 2, for example). The intake structure IS according to an embodiment of the present invention is particularly directed to the structure of the upstream portion of the intake pipe line 48, and more specifically to the intake duct structure.

As shown in FIG. 1, the intake pipe line 48 includes a connecting tube 50 connected to the intake device 46 of the engine 32, an air cleaner 52 connected to the end of the connecting tube 50, and the aforementioned air cleaner 52 that takes outside air into the air cleaner 52. An intake duct 54 is provided. The connecting tube 50 is a conduit that guides air from which foreign matter has been removed by the air cleaner 52 to the intake device 46 .

The air cleaner 52 is formed into a thin box shape whose dimension in the vehicle width direction is narrower than its dimension in the vertical direction in order to prevent bulging in the vehicle width direction. It is formed to extend in the direction. The air cleaner 52 is described in detail in, for example, Patent Document 1, so although not shown here, the air cleaner 52 includes an inner housing disposed inside the vehicle body 14, an outer housing 52a facing the inner housing, and an outer housing 52a that faces the inner housing. and a partition plate provided between the inner casing and the outer casing 52a. The distal end of the connecting tube 50 is inserted into the inner casing, and the space on the inner casing side communicates with the connecting tube 50. The aforementioned partition plate of the air cleaner 52 partitions the internal space of the air cleaner 52 formed between the inner casing and the outer casing 52a into a space on the connecting tube 50 side and a space on the intake duct 54 side. The partition plate is provided with an opening, and a filter element is arranged in the opening. The air taken into the space on the outer housing 52a side passes through the filter element and moves to the space on the inner housing side, and at this time, foreign matter such as dust in the air is removed by the filter element.

A communication hole (not shown) is provided at the rear end of the outer casing 52a of the air cleaner 52, and an intake duct 54 is connected to the communication hole. The intake duct 54 is a conduit that takes air into the air cleaner 52. The intake duct 54 includes an intake duct main body 60, a duct case 62, and a duct case cover 64. FIG. 2 shows a cross-sectional view of a part of the motorcycle 10 at the position of the intake duct 54, FIG. 3 shows a perspective view of a part of the motorcycle 10 in FIG. 2, and FIG. A perspective view of the figure is shown. Note that FIG. 2 is a cross-sectional view taken along the line II-II in FIG. 1, and FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. FIG.

The intake duct main body 60 is a pipe member extending to the air cleaner 52 of the intake pipe line 48. The intake duct main body 60 is connected to the above-mentioned communication hole of the outer casing 52a of the air cleaner 52, and is bent and extended from the air cleaner 52 side toward the rear of the vehicle body 14, as shown in FIG. ing. The intake duct main body 60 is made of a flexibly elastically deformable elastomer material such as rubber. Here, the intake duct main body 60 is formed to have an elongated cross-sectional shape in which the dimension in the vehicle width direction is narrower than the dimension in the vertical direction, and has a reinforcing structure 60a formed of ribs on the outer periphery thereof.

A duct case 62 is connected to a tip 60b that is the upstream end of the intake duct main body 60. The intake duct main body 60 is connected to the duct case 62 by an engagement structure 60c, which is a mechanical connection means, as shown in FIGS. 2 and 3. The duct case 62 is made of a hard resin material and is configured as a substantially cylindrical member. In the installed state shown in FIG. 1, the duct case 62 is located on the upstream side opposite to the opening (downstream opening) 65 to which the intake duct main body 60 connects and the downstream opening 65, and extends upward from the vehicle body. An open opening (upstream opening) 66 is formed. Like the intake duct main body 60 to which it is connected, the duct case 62 is formed to have an elongated cross-sectional shape in which the dimension in the vehicle width direction is narrower than the dimension in the vertical or longitudinal direction, and particularly has a substantially rectangular cross-sectional shape. In the installed state shown in FIG. 1, the duct case 62 includes an inner wall portion 67 disposed inside the vehicle body, an outer wall portion 68 disposed outside the vehicle body opposite to the inner wall portion 67, and these wall portions. 67 and 68 (see, for example, FIGS. 1 and 4). The inner wall portion 67 and the outer wall portion 68 are each formed and arranged so as to extend in the longitudinal direction of the vehicle body. Note that the duct case 62 is not limited to having a substantially rectangular cross-sectional shape, but may have, for example, a substantially oval or substantially elliptical cross-sectional shape in which the dimension in the vehicle width direction is narrower than the dimension in the vertical direction or the longitudinal direction. The inner wall portion 67 and the outer wall portion 68 may be formed to be directly continuous with each other, or may have a substantially square cross-sectional shape. However, the cross-sectional shape of the duct case 62 is preferably a shape on a virtual plane orthogonal to the axis of the cylindrical interior of the duct case 62.

A duct case cover 64 is attached to the upper part of the vehicle body of the duct case 62. FIG. 5 shows a view of the vicinity of the intake duct 54 of the motorcycle 10 viewed from above. In FIG. 5, the rear carrier 38 is seen through, and the duct case cover 64 of the intake duct 54 is shown. Further, FIG. 6 shows a view of the intake duct 54 from below, and FIG. 7 shows a view of the inside of the duct case cover 64 with the duct case 62 omitted from FIG. Further, FIG. 8 shows a cross-sectional view of the intake duct 54 and its surroundings, taken at a position different from that in FIG. 2, particularly at a position on the rear side of the cutting position in FIG. 2, of the motorcycle shown in FIG. FIG. 9 shows a cross-sectional view of the area around the intake duct 54 of the motorcycle shown in FIG. 1, with the duct case cover omitted, as viewed from inside the vehicle body. Note that the duct case cover 64 is attached to the duct case 62 by mechanical connection means using screw members B or the like.

The duct case cover 64 is made of hard resin material. The duct case cover 64 includes a cover part 72 positioned above the upstream opening 66 of the duct case 62 so as to cover it, and an arm part 74 for connecting the duct case cover 64 to the rear frame 22. The arm portion 74 extends from the cover portion 72 toward the inside of the vehicle body, as shown in FIG. As shown in FIGS. 2 to 4, 6, and 7, the cover portion 72 extends over a wider range than the upstream opening 66, and reaches above the outer wall portion 68 on the outside of the vehicle body, and extends on the inside of the vehicle body. It extends further inward beyond the wall portion 67.

As shown in FIGS. 2 to 4, the cover section 72 includes an upper wall section 76 that extends to face the upstream opening 66 of the duct case 62, and a section from the periphery of the upper wall section 76 to one side of the upper wall section 76. It includes a side wall portion 78 extending toward the side, that is, toward the bottom. As shown in FIG. 4, the side wall portion 78 has a partially cut-out portion and has a structure for increasing rigidity together with the arm portion 74, but is not limited to this, and may be formed in an annular shape, for example. In the intake duct 54 in which the duct case cover 64 is positioned above the upstream opening 66 of the duct case 62, the inner wall portion 67 of the duct case 62 does not extend to the cover portion 72, and the inner wall portion 67 and A gap 54G is formed between the cover part 72 and the cover part 72. On the other hand, the

other wall portions

68, 69, and 70 are connected to corresponding portions of the side wall portion 78, respectively.

In the intake duct 54 , an area defined outside the duct case 62 by the side wall 78 of the duct case cover 64 and the inner wall 67 of the duct case 62 is defined as an upstream intake passage of the intake duct 54 . 80 and opens on the lower side of the vehicle body. In other words, the opening 82 serving as the intake inlet of the intake duct 54 opens toward the lower side of the vehicle body. The upstream intake passage 80 is connected to a region inside the inner wall portion 67 of the duct case 62, that is, to the downstream intake passage 84 via the gap 54G. The downstream intake passage 84 is a region defined within the duct case 62 . In this way, the inner wall portion 67 of the duct case 62 functions as a partition portion, that is, a partition wall W, that separates the upstream intake passage 80 from the downstream intake passage 84 connected to the downstream side of the upstream intake passage 80. As is clear from FIG. 2, in the intake duct 54 located on the left side of the vehicle body, the upstream intake passage 80 extends vertically inside the vehicle body, that is, inside the vehicle width direction, and the downstream intake passage 84 connects to the upstream intake passage 80. On the other hand, the upstream intake passage 80 extends in the vertical direction on the outside of the vehicle body and is connected to the downstream intake passage 84 via the upper gap 54G. The gap 54G serves as an intra-duct communication portion that communicates the upstream intake passage 80 and the downstream intake passage 84.

A rear partition portion 85 is provided on the outer surface of the inner wall portion 67 of the duct case 62 so as to define the rear side of the upstream intake passage 80. The rear partition portion 85 extends in the vehicle width direction from the outer surface of the inner wall portion 67 and extends to the inner surface of the side wall portion 78 of the duct case cover 64. As shown in FIGS. 2 and 3, the rear partition 85 extends from the upper end of the inner wall 67 to below the lower end of the side wall 78. Therefore, the outside air that has reached the opening 82 of the intake duct 54 from the front side of the vehicle hits the rear partition 85 and can flow into the opening 82 . Note that the duct case 62 is not provided with a wall portion that defines the front side of the upstream intake passage 80 and has approximately the same size as the rear partition portion 85; This allows fresh air to flow from the front side.

A protrusion 86 is provided on the inner wall 67 of the duct case 62, which is the partition wall W. The protrusion 86 may also be referred to as a protrusion rib. The protrusion 86 is provided to prevent foreign matter such as dust from entering the intake duct 54 and is configured to protrude into the upstream intake passage 80 . More specifically, in FIGS. 2 and 3, the upper end portion of the inner wall portion 67 of the duct case 62 facing the cover portion 72 is formed as a protruding portion 86. The protruding portion 86 has a downwardly inclined surface 86a extending obliquely upward and toward the inside of the vehicle body from the inner wall portion 67, and further has an upper side surface 86c extending slightly obliquely upwardly toward the outside of the vehicle body from the upper end 86b of the downwardly inclined surface 86a. have The upper end 86b of the downwardly inclined surface 86a, that is, the bent portion 86d between the downwardly inclined surface 86a and the upper surface 86c faces the sidewall 78 of the duct case cover 64, and together with the sidewall 78 defines the opening 82 of the intake duct 54. Form. In this way, the side wall portion 78 of the duct case cover 64 extends downward from the cover portion 72 to the position of the upper end portion 86b of the downwardly inclined surface 86a in the vertical direction of the vehicle body. Note that the protrusion 86 is provided with reinforcing

ribs

86e and 86f.

Air flowing in from the opening 82 flows through the upstream intake passage 80 from the bottom to the top, passes through the gap 54G, flows into the downstream intake passage 84, and flows through the downstream intake passage 84 from the top to the bottom. It flows toward the side and flows into the intake duct main body 60. In this way, the flow direction of intake air in the upstream intake passage 80 is different from the flow direction of intake air in the downstream intake passage 84. In order to ensure a smooth flow of intake air from the upstream intake passage 80 to the downstream intake passage 84, the intake duct 54 has a direction from the upstream intake passage 80 side to the downstream intake passage 84 side. A concave curved portion 88 extending in a concave manner is formed. Although the concave curved portion 88 is provided on the duct case cover 64 here, it may be formed separately from the duct case cover 64 and provided on the intake duct 54.

The concave curved portion 88 is provided so as to extend to a boundary portion 89 that connects the upstream intake passage 80 and the downstream intake passage 84. The concave curved portion 88 extends across the gap 54G.
More specifically, the concave curved portion 88 forms a part of the upper wall surface portion 76 of the cover portion 72 and has an arcuate cross section extending from directly above the upstream intake passage 80 to the upstream side of the downstream intake passage 84. It has a concave curved surface 88s. This concave curved surface 88s extends so as to face the upper end portion of the inner wall portion 67, that is, the protrusion portion 86. The concave curved surface 88s is formed so that the flow path area of the opening 82 is generally maintained up to the upstream side of the downstream intake passage 84. The concave curved surface 88s is formed so as to extend toward the lower side of the vehicle body toward the downstream side and toward the downstream side of the intake passage 84 (see FIG. 2).

Further, a partition portion (second partition portion) 90 is provided that extends from the upper wall surface portion 76 of the duct case cover 64 toward the lower side of the vehicle body toward the downstream intake passage 84 . The second partition 90 defines a part of the space S1, which has an open end 90a connected to the downstream intake passage 84 and a closed end 90b opposite to the open end 90a. The second partition portion 90 is a wall portion extending in the front-rear direction of the vehicle body, and extends downward from the inner surface of the cover portion 72 of the duct case cover 64. Here, the lower end of the second partition section 90 is connected to the downstream end of the concave curved section 88 and is integrated with the concave curved section 88 . As a result, a space S1 is formed on the outside of the vehicle body of the second partition part 90 by the second partition part 90, the upper wall part 76 and the side wall part 78, and the

walls

68, 69, and 70 of the duct case 62, On the downstream side of the concave curved portion 88, the space S1 is connected to the downstream intake passage 84. This space S1 can function as a resonator, and is designed, for example, to exhibit a silencing effect.

As shown in FIGS. 1 and 2, the opening 82 at the upstream end of the upstream intake passage 80 of the intake duct 54 configured as described above is located above the rear cushion 44 disposed on the left side of the rear wheel 42. , is positioned further back of the vehicle body than the axis C of the rear cushion 44. As is clear from FIG. 2, the opening 82 is located at the rear of the rear cushion 44. Furthermore, as is clear from FIG. 2, the opening 82 of the intake duct 54 is positioned on the outer side of the vehicle body with respect to the axis C of the rear cushion 44 in the vehicle width direction.

Further, the intake duct 54 defining the opening 82 is positioned below the rear carrier 38 of the vehicle body. As shown in FIG. 5, an intake duct 54 is provided below the left front corner of the rear carrier 38 along the shape of the rear carrier 38. As shown in FIG.

FIG. 10 shows a view of the motorcycle 10 cut in the middle in the front-rear direction and its rear portion viewed from the front. However, in the motorcycle 10 shown in FIG. 10, the rear carrier 38 is in a removed state. The fuel tank 36 is located below the vehicle body of the seat 12, and the air cleaner 52 is located on the lower side of the fuel tank 36, here on the left side. As is clear from FIG. 10, the width of the fuel tank 36 in the vehicle width direction is smaller than the width of the seat 12 in the vehicle width direction (left-right width LH−RH). As a result, a concave region, that is, a concave space S2, is defined between the seat 12, the fuel tank 36, and the air cleaner 52, through which the traveling wind, that is, the air, can flow from the front to the rear of the vehicle body. In FIG. 10, the driver's feet are further schematically shown with broken lines. The driver's left foot DL substantially defines the outside of the space S2. The intake duct 54 is positioned at the rear of the recessed space S2 formed in this manner. That is, the intake duct 54 is provided as described above so that the opening 82 at the upstream end of the upstream intake passage 80 opens at the rear of the vehicle in the recessed space S2. In addition, in FIG. 10, the exhaust device 32e of the engine 32 extends to the right side of the fuel tank 36.

The effects of the intake structure IS having the intake duct 54 having the above configuration and arrangement will be described below.

The intake duct 54 is provided in the motorcycle 10 equipped with the engine 32 having the intake pipe 48 arranged to extend toward the rear of the vehicle body, and has the characteristic intake structure IS described above. The intake duct 54 includes an intake duct main body 60 extending to the air cleaner 52 of the intake pipe line 48 , and is connected to an upstream intake passage 80 and to the downstream side of the upstream intake passage 80 . An inner wall portion 67 of the duct case 62 is provided, which serves as a partition portion, that is, a partition wall W, separating the downstream intake passage 84 having a flow direction different from the flow direction. Therefore, entry of water, dust, etc. into the intake duct 54 can be suitably prevented. In particular, the upstream intake passage 80 opens toward the lower side of the vehicle body, and its opening 82 allows intake air to flow from the lower side of the vehicle body to the upper side. Therefore, it is possible to more reliably prevent water, dust, and the like from entering into the intake duct 54 through the opening 82.

Furthermore, the intake duct 54 is provided with a concave curved portion 88 extending from the upstream intake passage 80 side toward the downstream intake passage 84 side, that is, its concave curved surface 88s. Therefore, the flow of intake air from the upstream intake passage 80 side to the downstream intake passage 84 side can be made smooth. Therefore, it becomes possible to take in more intake air through the intake duct 54, and a sufficient amount of intake air can be ensured. In particular, the concave curved portion 88 is provided so as to extend to the boundary portion 89 that connects the upstream intake passage 80 and the downstream intake passage 84, so that it extends from the upstream intake passage 80 side to the downstream intake passage 84 side. The flow of intake air to the engine 32 can be made smoother, and therefore the performance of intake air to the engine 32 can be improved. Therefore, it is possible to secure a sufficient amount of intake air without having to form both the first flow path and the second flow path in the intake duct as in the saddle type vehicle of Patent Document 1. becomes possible.

The intake duct 54 is provided with a protrusion 86 that projects into the upstream intake passage 80. Therefore, the protrusion can better prevent mud, dust, etc. from entering the intake duct 54 from below the vehicle body. In particular, since the protrusion 86 is provided on the inner wall 67 of the duct case 62, which is the partition wall W, the protrusion 86 can be provided without increasing the number of parts constituting the intake duct 54.

Further, a second partition part 90 is further formed in the intake duct to define a space S1 having an open end 90a connected to the downstream intake passage 84 and a closed end 90b on the opposite side. The space S1 can function to suppress intake pulsation, and can play the role of a so-called resonator. Therefore, intake noise can be suppressed.

The opening 82 at the upstream end of the upstream intake passage 80 is located above the rear cushion 44 disposed on the side of the rear wheel 42 and extends toward the rear of the vehicle body relative to the axis C of the rear cushion 44. However, it is positioned behind the rear cushion 44. By locating the opening 82 at such a position, the intake duct 54 can be extended to the rear of the rear cushion 44, thereby ensuring a long length of the intake duct 54 in the front-rear direction (for example, as shown in FIGS. 8 and 9). reference).
Thereby, the motorcycle 10 can suppress intake noise without impairing comfort for the driver and power performance. Furthermore, the opening 82 of the intake duct 54 is positioned further outward of the vehicle body than the axis C of the rear cushion 44 disposed on the side of the rear wheel 42 in the vehicle width direction. Therefore, it becomes possible to prevent mud, dust, etc. from entering the intake duct 54 from the rear wheel 42 more appropriately.

Furthermore, the intake duct 54 is positioned below the rear carrier 38 of the vehicle body. That is, the opening 82 of the intake duct 54 is provided at a position overlapping the rear carrier 38 when viewed from above in FIG. By arranging the rear carrier 38 and the opening 82 of the intake duct 54 so as to overlap each other in this manner, intake noise transmitted to the driver from the opening 82 can be suppressed. Furthermore, although the area below the rear carrier 38 tends to become a dead space, by arranging the intake duct 54 there, the space can be effectively utilized.

Furthermore, as shown in FIG. 10, in the intake structure IS, a recessed space S2 is formed on the side of the fuel tank 36 below the vehicle body of the seat 12, more specifically, between the seat 12, the fuel tank 36, and the air cleaner 52. were formed into sections. Then, the intake duct 54 is provided so that the opening 82 opens at the rear of the vehicle in the recessed space S2. Therefore, the recessed space S2 can be used as a travel wind guide, and the travel wind, that is, air, can be efficiently sucked in through the opening 82 of the intake duct 54.

The intake duct 54 includes a duct case 62 to which the upstream end of the intake duct main body 60 is connected, and a duct case cover 64 attached to the upper part of the vehicle body of the duct case 62. The aforementioned concave curved portion 88 is provided on the duct case cover 64, and the aforementioned partition wall W is provided on the duct case 62. Therefore, the intake structure IS having the intake duct 54 can achieve the various effects described above without increasing the number of parts of the intake duct 54.

Although the embodiments according to the present invention have been described above, the present invention is not limited thereto. Various substitutions and changes can be made without departing from the spirit and scope of the invention as defined by the claims of this application.

In the above embodiment, the intake system of the engine 32 extends to the left side of the vehicle body, and the exhaust system of the engine 32 extends to the right side of the vehicle body. However, the intake system of the engine 32 may extend to the right side of the vehicle body, and the exhaust system of the engine 32 may extend to the left side of the vehicle body.

10...Motorcycle (straddle type vehicle)
12...Seat 14...Vehicle body 28...Front wheel 32...Engine (internal combustion engine)
42... Rear wheel 44... Rear cushion 46... Intake device 50... Connecting tube 52... Air cleaner 54... Intake duct 60... Intake duct body 62... Duct case 64... Duct case cover 67... Inner wall portion 80... Upstream intake passage 82... Opening part 84...Downstream intake passage 86...Protrusion part 88...Concave curved part 90...Partition part (second partition part)
IS...Intake structure W...Partition wall (partition part)

Claims

An intake structure (IS) of an internal combustion engine (32) in a straddle-type vehicle (10),
It is provided in the intake duct (54) upstream of the air cleaner (52) of the internal combustion engine (32), and is connected to the upstream intake passage (80) and the downstream side of the upstream intake passage (80). a partition portion (W) that separates the flow direction of the upstream intake passage (80) from the downstream intake passage (84) having a different flow direction;
An intake structure (IS) comprising a concave curved portion (88) extending from the upstream intake passageway (80) side toward the downstream intake passageway (84) side.
The intake structure (IS) according to claim 1, wherein the upstream intake passage (80) opens toward a lower side of the vehicle body.
The concave curved portion (88) is provided to extend to a boundary portion (89) connecting the upstream intake passage (80) and the downstream intake passage (84). The intake structure (IS) according to claim 1 or claim 2.
The intake structure (IS) according to any one of claims 1 to 3, further comprising a protrusion (86) projecting into the upstream intake passage (80).
The intake structure (IS) according to claim 4, wherein the protrusion (86) is provided on the partition (W).
a second partition that at least partially partitions a space (S1) having an open end (90a) connected to the downstream intake passage (84) and a closed end (90b) opposite to the open end (90a); Intake structure (IS) according to any one of claims 1 to 5, characterized in that a section (90) is further formed in the intake duct (54).
The opening (82) at the upstream end of the upstream intake passage (80) is above the rear cushion (44) disposed on the side of the rear wheel (42) of the straddle-type vehicle (10). The intake structure (IS) according to any one of claims 1 to 6, wherein the intake structure (IS) is located further rearward of the vehicle body than the axis (C) of the rear cushion (44).
The intake duct (54) is positioned below the vehicle body of the rear carrier (38) of the straddle-type vehicle (10). Intake structure (IS).
The saddle type vehicle (10) has a fuel tank (36) below the seat (12),
The air cleaner (52) is arranged on the lower side of the fuel tank (36),
The width of the fuel tank (36) in the vehicle width direction is smaller than the width of the seat (12) in the vehicle width direction;
An opening at the upstream end of the upstream intake passage (80) is located at the rear of the vehicle in a recessed space (S2) defined between the seat (12), the fuel tank (36), and the air cleaner (52). The air intake structure (IS) according to any one of claims 1 to 8, wherein the air intake duct (54) is provided so that the air intake structure (IS) is opened.
The intake duct (54) is
a duct case (62) to which an upstream end of an intake duct body (60) extending to the air cleaner (52) is connected;
The intake structure (IS) according to any one of claims 1 to 9, further comprising a duct case cover (64) attached above the vehicle body of the duct case (62).
The air intake structure (IS) according to claim 10, wherein the concave curved portion (88) is provided on the duct case cover (64).
The intake structure (IS) according to claim 10 or 11, wherein the partition portion (W) is provided in the duct case (62).