WO2018056118A1

WO2018056118A1 - Cooling structure for internal combustion engine for saddled vehicle

Info

Publication number: WO2018056118A1
Application number: PCT/JP2017/032876
Authority: WO
Inventors: 耕一朗松下; 恭義藤田; 裕介富岡
Original assignee: 本田技研工業株式会社
Priority date: 2016-09-21
Filing date: 2017-09-12
Publication date: 2018-03-29
Also published as: CN109715912B; JPWO2018056118A1; JP6660477B2; CN109715912A

Abstract

This cooling structure for an internal combustion engine for a saddled vehicle is configured such that a crankshaft 31 aligned with the vehicle width direction is provided to a crankcase 30 of the internal combustion engine 3, a centrifugal cooling fan 7 is provided at an end of the crankshaft, a radiator 6 is provided facing the cooling fan 7, and a shroud 8 is provided surrounding the cooling fan 7. The shroud 8 has a first air-directing guide plate 101 and a second air-directing guide plate 102, which are formed such that the radial width thereof measured from the axis C of rotation of the cooling fan increases in the direction R of rotation of the cooling fan. Spaces 88, 89 formed by the first air-directing guide plate 101 and the second air-directing guide plate 102 are continuous, on the side on which the radial width is increased, with an air discharge opening 80 for discharging discharge air, and the spaces 88, 89 are arranged facing each other across the axis of rotation of the cooling fan. As a result, the size, in the radial width direction, of a swirl chamber inside the shroud can be restricted, and air discharge efficiency is increased while interference with a peripheral member is prevented.

Description

Cooling structure of internal combustion engine for saddle riding type vehicle

The present invention relates to a cooling structure of a straddle-type vehicle internal combustion engine, and more particularly to a shroud structure surrounding a cooling fan.

The crankcase of a water-cooled internal combustion engine of a saddle-ride type vehicle is provided with a crankshaft oriented in the vehicle width direction, with a centrifugal cooling fan at the end thereof, and on the upstream side of the cooling fan in the flow direction of the cooling air A cooling structure for a straddle-type internal combustion engine for a straddle-type vehicle in which a radiator, a so-called butto-in radiator, is provided and a single vortex chamber is provided in a shroud that surrounds a cooling fan has been conventionally disclosed in Patent Document 1, for example. Yes.

JP 2007-016727 A (FIGS. 4 to 6)

In the cooling structure as shown in Patent Document 1, it is necessary to increase the shroud vortex chamber in order to make it easy to ensure the amount of cooling air from the radiator and to improve the exhaust efficiency. When the size is increased, the shroud becomes larger, and there is a risk of interference with peripheral members.
SUMMARY OF THE INVENTION In view of the above prior art, the present invention is an internal combustion engine for a straddle-type vehicle provided with a centrifugal cooling fan, provided with a radiator facing the upstream side of the cooling fan, and provided with a vortex chamber in a shroud surrounding the cooling fan. In this cooling structure, the size of the vortex chamber in the radial width direction from the rotation axis of the cooling fan can be suppressed as compared with the air volume, and the exhaust efficiency can be improved without interfering with peripheral members. An object of the present invention is to provide a cooling structure for a straddle-type vehicle internal combustion engine.

In order to solve the above problems, according to the present invention, a crankcase of a water-cooled internal combustion engine of a saddle-ride type vehicle is provided with a crankshaft oriented in the vehicle width direction, and a centrifugal type is provided at an end of the crankshaft. In a cooling structure for a straddle-type vehicle internal combustion engine, provided with a cooling fan, provided with a radiator facing the upstream side of the cooling fan in the flow direction of the cooling air, and provided with a shroud surrounding the cooling fan The first wind guide plate and the second wind guide plate are formed on the outer periphery of the shroud so as to increase the radial width from the rotation axis of the cooling fan according to the rotation direction of the cooling fan. Each of the spaces formed by the first air guide plate and the second air guide plate is continuous with the air outlet for discharging the air from the cooling fan on the side where the radial width is enlarged, The cooling structure for a straddle-type vehicle internal combustion engine, wherein the first air guide plate and the second air guide plate are disposed to face each other across the rotation axis of the cooling fan. Is provided.

According to a preferred embodiment of the present invention, each of the first wind guide plate and the second wind guide plate has an angle of 90 degrees or more and 180 degrees or less around the rotation axis of the cooling fan. Formed in the range.

According to a preferred embodiment of the present invention, the exhaust port of the shroud includes a lower exhaust port, a rear exhaust port, and an upper exhaust port, and the lower exhaust port exhausts air toward the exhaust pipe. The rear exhaust port is disposed so as to exhaust air toward the vehicle rear side, and the upper exhaust port is disposed so as to be exhausted into the crankcase.

In a preferred embodiment of the present invention, the first wind guide plate is formed on the vehicle front side of the shroud, and the space formed by the first wind guide plate in the rotation direction of the cooling fan is The downstream side is continuous with the lower exhaust port and the rear exhaust port, and the second air guide plate is formed on the vehicle rear side of the shroud, and the second direction guide plate The space formed by the wind guide plate is continuous with the upper air outlet on the downstream side.

According to another preferred embodiment of the present invention, an exhaust outlet branching portion is formed between the lower exhaust outlet and the rear exhaust outlet, and the exhaust air guided from the first air guide plate is It is configured so as to be diverted to the lower exhaust port and the rear exhaust port through the exhaust port branching portion.

In a preferred embodiment of the present invention, the rear side air exhaust port overlaps at least a part with an oil level gauge provided in the crankcase in a rear view.

In another preferred embodiment of the present invention, the exhaust pipe leading to the exhaust muffler is provided with a catalyst internal part in which a catalyst is provided in the middle, and the catalyst internal part is at least partially in a side view. In addition to being disposed below the shroud, the catalyst inner portion is disposed at a position where at least a portion thereof does not overlap the lower exhaust port as viewed from below.

According to the cooling structure for an internal combustion engine for a saddle-ride type vehicle of the present invention, two vortex chambers are formed in the shroud by the first wind guide plate and the second wind guide plate, so that one vortex chamber is formed. Compared to the airflow, the size of the vortex chamber in the radial width direction from the rotation axis of the cooling fan can be reduced compared to the airflow, and the exhaust efficiency is improved without causing interference with surrounding members. Can be made.

The first air guide plate and the second air guide plate are formed in an angle range of 90 degrees or more and 180 degrees or less around the rotation axis of the cooling fan, respectively. The first vortex chamber, which is a space formed by the wind guide plate, and the second vortex chamber, which is a space formed by the second wind guide plate, both have a sufficient size and are biased toward one side. Without this, the wind is smoothly discharged and the wind exhaust efficiency can be improved.

The exhaust port of the shroud includes a lower exhaust port, a rear exhaust port, and an upper exhaust port, and the lower exhaust port is disposed so as to exhaust air toward an exhaust pipe, and the rear exhaust port An air outlet is disposed so as to be exhausted toward the rear side of the vehicle, and the upper air outlet is disposed so as to be exhausted into the crankcase, whereby the upper air outlet and the lower side are disposed on the shroud. By providing three air exhaust ports, the air exhaust port and the rear air exhaust port, the air exhaust becomes smooth and easy, and the air exhaust efficiency is improved.

The first wind guide plate is formed on the vehicle front side of the shroud, and a space formed by the first wind guide plate in the rotational direction of the cooling fan is downstream of the lower exhaust. A space that is continuous with the air outlet and the rear air outlet, and the second air guide plate is formed on the vehicle rear side of the shroud and is formed by the second air guide plate in the rotation direction of the cooling fan. However, the second vortex chamber is a space formed by the first vortex guide plate and the second vortex guide plate, which is a space formed by the first air guide guide plate. The vortex chambers are continuous with each other in a well-balanced manner, and are continuously connected to the lower exhaust port, the rear exhaust port, and the upper exhaust port, so that the exhaust efficiency is improved.

An exhaust outlet branch part is formed between the lower exhaust outlet and the rear exhaust outlet, and the exhaust air guided from the first air guide guide plate passes through the exhaust outlet branch part to the lower exhaust outlet. By being divided so as to be diverted to the air outlet and the rear air outlet, the air exhaust guided from the first air guide guide plate is discharged from the lower air outlet and the rear air outlet at the air outlet branching portion. The air can be discharged by being diverted to the air outlet, and even when the state of the air discharge destination changes, stable air can be discharged, and the amount of air discharged can be secured.

When the rear air outlet is at least partially overlapped with an oil level gauge provided in the crankcase in the rear view, at least a part of the rear air outlet is covered from behind by the oil level gauge. Further, it is possible to make it difficult for foreign matter to enter the shroud from the rear side exhaust port.

The exhaust pipe leading to the exhaust muffler is provided with a catalyst internal part in which a catalyst is provided in the middle, and the catalyst internal part is disposed at least partially below the shroud in a side view, and the catalyst Since the inner portion is arranged at a position where at least a portion does not overlap the lower exhaust port in the bottom view, the exhaust pipe and the catalyst inner portion are disposed below the lower exhaust port. The exhaust pipe is cooled and the catalyst is also cooled. On the other hand, if the catalyst internal portion is arranged so as to block the lower side of the lower exhaust port, the exhaust air does not flow efficiently. Therefore, at least a part of the catalyst internal portion in the bottom view is seen from the lower exhaust port. By disposing at a position that does not overlap the exhaust air, the exhaust air can be exhausted without being disturbed by the catalyst internal portion.

1 is a right side view of a motorcycle including a cooling structure for a straddle-type vehicle internal combustion engine according to an embodiment of the present invention. FIG. 2 is a right side view showing an internal combustion engine portion of the power unit in FIG. 1 with a vehicle body cover and a radiator cover removed. FIG. 3 is a cross-sectional view of the internal combustion engine and its buttle radiator as viewed in the direction of arrows III-III in FIG. 2. FIG. 4 is a left side view of a small unit unit including a radiator and a shroud fixed to the radiator, generally corresponding to a view taken along arrows IV-IV in FIG. 3. FIG. 5 is a left side view of the shroud shown in the same direction as in FIG. 4 with the radiator and the partition plate removed in FIG. 4. FIG. 6 is a cross-sectional view of the shroud as viewed in the direction of arrows VI-VI in FIG. 5. 6 is a left side perspective view of the left side surface of the shroud shown in FIG. FIG. 5 is a right side view of the internal combustion engine portion of the power unit, shown in the same direction as in FIG. 2, but the shroud portion is generally shown by a cross-section taken along arrow VIII-VIII in FIG. FIG. 9 is a bottom view of the internal combustion engine portion of the power unit, taken along line IX-IX in FIG. 8. FIG. 9 is a rear cross-sectional view of the internal combustion engine portion of the power unit, taken along line XX in FIG. 8.

A cooling device for a straddle-type vehicle internal combustion engine according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, a straddle-type vehicle equipped with a cooling device for a vehicle internal combustion engine according to the present embodiment is a scooter type motorcycle 1 equipped with a unit swing type power unit 5, and claims and The directions such as front, rear, left, right, up and down in the description of the specification shall follow the direction of the motorcycle 1 provided with the cooling device of the present embodiment.
1 to 10, arrows FR indicate the front of the vehicle, LH indicates the left side of the vehicle, RH indicates the right side of the vehicle, and UP indicates the upper side of the vehicle.
In addition, in each figure, the white small arrow shows the flow of exhaust air (cooling air) typically.

As shown in FIG. 1, the vehicle body of the scooter type motorcycle 1 of this embodiment is shown on the right side of the motorcycle 1 that is a saddle type vehicle equipped with the cooling device for the internal combustion engine for the saddle type vehicle according to this embodiment. The frame 2 includes a head pipe 20 at its front end, a main frame 21 whose front end is coupled to the head pipe 20, a cross pipe 22 in the vehicle width direction provided at the rear of the main frame 21, and both ends of the cross pipe 22. And a rear frame 23 comprising a pair of left and right rear frame rods whose front end portions are connected to each other.

A front fork 11 that supports the front wheel 10 and a rod-shaped steering handle 12 are supported on the head pipe 20 so as to be steerable. The main frame 21 integrally includes a down frame portion 21a inclined downward from the head pipe 20 and a lower frame portion 21b extending substantially rearward from the rear end of the down frame portion 21a. Is formed by bending.
Further, the rear frame 23 is inclined upward and backward from the cross pipe 22, and is inclined upward and backward from the upper end of the rising frame portion 23a at a gentler inclination angle than the rising frame portion 23a. A seat rail portion 23b extending rearward is integrally formed, and a single pipe is formed by bending.

A bracket 24 is provided at the front part of the left and right rear frames 23 in the body frame 2, that is, below the rising frame part 23a, and one end of a hanger part 55 provided at the front lower part of the unit swing type power unit 5 is provided on the bracket 24. The other end of the link 13 connected through the support shaft 55a is connected through the support shaft 24a, and the power unit 5 is swingably supported by the vehicle body frame 2 while being able to swing up and down. The rear wheel 14 is pivotally supported on the rear part of the power unit 5. A rear cushion unit 15 is provided between the rear part of the seat rail part 23 b of the left rear frame rod and the rear part of the power unit 5 among the pair of left and right rear frame rods of the rear frame 23.

A storage box 16 is supported between the front portions of both rear frames 23 in the body frame 2, and a tandem type riding seat 17 that covers the storage box 16 from above is supported on the front upper portion of the storage box 16. The Further, a fuel tank 18 supported by both rear frames 23 is disposed behind the storage box 16 so as to be covered with the riding seat 17.
The vehicle body frame 2, a part of the power unit 5, the storage box 16 and the fuel tank 18 are covered with a vehicle body cover 25.

FIG. 2 is a right side view showing the internal combustion engine 3 portion of the power unit 5 in FIG. 1 with the vehicle body cover 25 removed, and is shown with the radiator cover 9 described later removed.
The power unit 5 includes a water-cooled internal combustion engine 3 and a power transmission device (not shown) that extends rearward from the left side of the internal combustion engine 3 and transmits the rotational power of the internal combustion engine 3 to the rear wheels 14. The internal combustion engine 3 is coupled to the crankcase 30 with a crankcase 30 that rotatably supports a crankshaft 31 having an axis oriented in the vehicle width direction and a cylinder axis that is slightly inclined upward. A cylinder block 32, a cylinder head 33 coupled to the cylinder block 32, and a head cover 34 coupled to the cylinder head 33.

As shown in FIG. 3 which is a cross-sectional view of the internal combustion engine 3 and its so-called butto radiator as viewed in the direction of arrows III-III in FIG. 2, the crankcase 30 is divided into a left crankcase half 30L divided into left and right parts and a right crankcase 30L. A crankcase half 30R is fastened by a plurality of bolts 30a, and an ACG 40, that is, an alternator is provided at the right shaft end 31a of the crankshaft 31 that rotatably passes through the right crankcase half 30R. It is attached.

The outer rotor 41 of the ACG 40 is fixed to the right shaft end 31a of the crankshaft 31, and the inner stator 42 surrounded by the outer rotor 41 so as to form the ACG 40 together with the outer rotor 41 is attached to the right crankcase half 30R. It is fixed to the support plate 35 to be fastened.

In the cooling device for an internal combustion engine for a saddle-ride type vehicle according to the present embodiment, a so-called butlt-in radiator is provided, and the radiator 6 is disposed on the axial extension to the right side of the crankshaft 31 oriented in the vehicle width direction. A centrifugal cooling fan 7 disposed inward of the radiator 6 is connected to the shaft 31 in a coaxial manner, and a plurality of cooling fans 7 are arranged so as to be disposed between the radiator 6 and the ACG 40. The bolt 75 is fixed to the outer rotor 41 of the ACG 40.

Between the radiator 6 and the right crankcase half 30 </ b> R of the crankcase 30, there is a shroud (or “fan case” or “radiator base”) 8 that surrounds the cooling fan 7 and is fixed to the radiator 6. A radiator cover 9 that is interposed and covers the radiator 6 from the right outer side is fastened to the shroud 8.
The radiator 6 includes an upper tank 61 provided with a filler neck 60 extending upward, a lower tank 62 disposed below the upper tank 61, a core portion 63 provided between the upper tank 61 and the lower tank 62, And a tank cover 64 that covers the tank 61 from the outside in the vehicle width direction.

As shown in FIG. 2, a water pump 36 interlocking with the rotation of the crankshaft 31 is disposed on the right side surface of the cylinder head 33 in the internal combustion engine 3, and the cooling water discharged from the water pump 36 is a hose. It is introduced into a water jacket (not shown) of the cylinder block 32 through 50. Cooling water discharged from a water jacket (not shown) formed in the cylinder head 33 so as to communicate with the water jacket of the cylinder block 32 is guided to the upper tank 61 of the radiator 6 through the hose 51, and Cooling water cooled by circulating the core portion 63 from the tank 61 is led out from the lower tank 62 by the hose 52. On the other hand, a thermostat 53 is fixedly disposed on the right side of the cylinder block 32, and a hose 52 that guides cooling water from the lower tank 62 is connected to the thermostat 53. Further, the cooling water led out from the water jacket of the cylinder head 33 can be guided to the thermostat 53 via the bypass hose 54, and the thermostat 53 is connected to the suction pipe 36 a of the water pump 36.

As shown in FIG. 3 (see also FIG. 2), one radiator mounting portion 81a projecting downward is integrally provided at a lower portion of the outer end portion of the shroud 8 in the vehicle width direction, and the radiator mounting portion 81a is integrally provided. Is attached to the mounting plate portion 65a provided integrally with the lower tank 62 of the radiator 6 from the outside and fastened by the screw member 82.

Further, as shown in FIG. 2, a pair of

radiator mounting portions

81b and 81b are integrally provided at the upper portion of the outer end portion of the shroud 8 in the vehicle width direction so as to protrude upward and backward of the filler neck 60. The

radiator mounting portions

81b and 81b are fastened by screw members 82 to mounting

plate portions

65b and 65b that are integrally provided in the upper tank 61 of the radiator 6 and abut against the

radiator mounting portions

81b and 81b from the outside. The

That is, the shroud 8 is fastened to the radiator 6, and when the radiator 6 is fixed to the right crankcase half 30 </ b> R of the crankcase 30, the small unit 66 composed of the radiator 6 and the shroud 8 fixed to the radiator 6 is provided. The crankcase 30 is fixed to the right crankcase half 30R.

The radiator 6 of the small unit 66 is directly fastened to the right crankcase half 30R of the crankcase 30. The upper tank 61 of the radiator 6 has a pair of crankcase mounting portions 67b before and after the filler neck 60. 67b is integrally provided so as to protrude sideways, and the

crankcase mounting portions

67a and 67a are provided integrally so that the radiator 6 protrudes downward at two positions spaced apart from each other in the front and rear of the lower tank 62. It is done.

On the other hand, as shown in FIG. 3, the right crankcase half 30R of the crankcase 30 has a stud 56 which is screwed into the right crankcase half 30R from the right and has a bottomed female screw hole 56a. The radiator 6 is screwed and fixed at a position corresponding to the

crankcase mounting portions

67a and 67b in the radiator 6, and the fixing bolt 58 inserted through the

crankcase mounting portions

67a and 67b is screwed into the female screw hole 56a to be tightened. Is directly fastened to the right crankcase half 30R of the crankcase 30. In this state, the shroud 8 is disposed so that the crankcase side end portion 83 of the shroud 8 contacts the right crankcase half 30R of the crankcase 30.

As shown in FIG. 3, the radiator cover 9 that covers the radiator 6 from the right outer side has a cooling air inlet 90 that opens to correspond to the core portion 63 of the radiator 6, and has a plurality of blade plates 91a. A louver 91 disposed in the cooling air inlet 90 is provided on the radiator cover 9.
The radiator cover 9 is fastened to the outer end portion of the shroud 8 in the vehicle width direction. As shown in FIG. 2, the upper and lower portions of the outer end portion of the front edge portion 8a of the shroud 8 in the vehicle width direction. In addition, a cover mounting portion 84 projecting outward is integrally provided at a lower portion of the outer end portion of the rear edge portion 8b of the shroud 8 in the vehicle width direction so as to abut the radiator cover 9, and each cover The radiator cover 9 is fastened to the attachment portion 84.

In the present embodiment, as shown in FIG. 3, a centrifugal cooling fan 7 that is surrounded by the shroud 8 and that has the axis of the crankshaft 31 as the rotation axis C is disposed. The shroud 8 An exhaust port 80 (see FIG. 2) that is provided on the downstream side of the radiator 6 in the direction and discharges cooling air that has passed through the radiator 6, that is, exhaust air, is formed surrounding the cooling fan 7.

4 is a left side view of the small unit 66 that roughly corresponds to the view taken along the line IV-IV in FIG. 3 and includes the radiator 6 and the shroud 8 fixed to the radiator 6.
In FIG. 4, the rotation direction R of the cooling fan 7 (not shown) is the counterclockwise rotation direction with respect to the rotation axis C shown in the figure, and is opened in the inner peripheral flange portion 85 of the shroud 8 so that the cooling fan 7 is concentric. The core portion 63 of the radiator 6 is seen at the end of the circular opening 85a to be inserted, but the surface shape is not shown.

The left end surface (the front side in the figure) of the shroud 8 shown in FIG. 4 is a portion that comes into contact with the right crankcase half 30R when the small unit 66 is fixed to the right crankcase half 30R, and the front (left side in the figure). A partition plate 86 that is parallel to the inner peripheral flange 85 is fastened to the periphery from the lower side to the rear side (right side in the figure), and in the periphery from the rear side (right side in the figure) to the upper side. A partition portion 87 parallel to the inner peripheral flange portion 85 is formed integrally with the inner peripheral flange portion 85.
A first vortex chamber 88 is formed between the inner peripheral flange portion 85 and the partition plate 86, and a second vortex chamber 89 is formed between the inner peripheral flange portion 85 and the partition portion 87.

5 is a left side view in which the radiator 6 on the right side (the other side in the figure) and the partition plate 86 on the left side (the front side in the figure) are removed, and only the main body of the shroud 8 is shown in the same direction as FIG. It is.
As shown in FIG. 5, the cooling fan 7 rotates around the inner peripheral flange portion 85 of the shroud 8 from the front upper portion to the lower portion according to the rotation direction R of the cooling fan 7, that is, from the upstream side to the downstream side. A first wind guide plate 101 is erected so as to gradually increase the radial width r1 from the axis C. The first wind guide plate 101 has a lower exhaust port 80a and a rear exhaust port 80b that constitute an exhaust port 80 for discharging the exhaust air from the cooling fan 7 on the side where the radial width r1 is enlarged, that is, on the downstream side. It is provided so that it may continue.
A first vortex chamber 88 is formed on the inner peripheral side of the first air guide plate 101 to receive and reduce the exhaust air from the cooling fan 7 and to increase the pressure, thereby providing a continuous lower exhaust port 80a and the rear side. The exhaust efficiency from the side exhaust port 80b can be improved.

Further, in the periphery from the rear side to the upper side of the inner peripheral flange portion 85 of the shroud 8, the radial width from the rotation axis C of the cooling fan 7 from the upstream side to the downstream side in accordance with the rotation direction R of the cooling fan 7. The second wind guide plate 102 is erected so as to gradually increase r2, and the second wind guide plate 102 is configured to discharge the wind from the cooling fan 7 on the side where the radial width r2 is increased, that is, on the downstream side. It is provided so as to be continuous with the upper air exhaust port 80c constituting the exhaust port 80 for discharging.
A second vortex chamber 89 is formed on the inner circumferential side of the second air guide plate 102 to receive the exhaust air from the cooling fan 7 and decelerate and increase the pressure, thereby exhausting air from the continuous upper air exhaust port 80c. Wind efficiency can be improved.

The first wind guide plate 101 and the second wind guide plate 102 are disposed to face each other across the rotation axis C of the cooling fan 7. Since the two

vortex chambers

88 and 89 are formed in the shroud 8 by the second air guide plate 102, the rotational axis C of the cooling fan 7 is compared to the amount of air compared to the case where one vortex chamber is formed. The first and

second vortex chambers

88 and 89 can be reduced in size in the radial width r1 and r2 directions, and the exhaust efficiency can be improved without interfering with the peripheral members.

In the present embodiment, the angle ranges α1 and α2 formed by the first wind guide plate 101 and the second wind guide plate 102 are 90 degrees or more and 180 degrees with the rotational axis C of the cooling fan 7 as the center in this embodiment. The first vortex chamber 88 formed by the first air guide guide plate 101 and the second vortex chamber 89 formed by the second air guide guide plate 102 are both sufficiently large. In addition, the exhaust air is smoothly performed without being biased in size, and the exhaust air efficiency can be improved.

Further, since the air outlet 80 of the shroud 8 has the lower air outlet 80a, the rear air outlet 80b, and the upper air outlet 80c as described above, the three

air outlets

80a, 80b, and 80c are provided. As a result, exhausting air is smooth and easy, and exhausting efficiency is improved.
Moreover, the first wind guide plate 101 is formed on the vehicle front side of the shroud 8, and the downstream side in the rotation direction R of the cooling fan 7 is continuous with the lower air outlet 80 a and the rear air outlet 80 b, and the second Since the wind guide plate 102 is formed on the vehicle rear side of the shroud 8 and is disposed so that the downstream side in the rotation direction R of the cooling fan 7 is continuous with the upper air exhaust port 80c, the first wind guide plate 101 is provided. The first vortex chamber 88 formed by the second vortex chamber 89 and the second vortex chamber 89 formed by the second air guiding guide plate 102 are respectively well balanced with the lower air outlet 80a and the rear air outlet 80b, Continuing to the exhaust port 80c, the exhaust efficiency is improved.

Then, as shown in FIG. 5, an exhaust outlet branching portion 103 standing on the inner peripheral flange 85 is formed between the lower exhaust outlet 80a and the rear exhaust outlet 80b. Exhaust air guided from the wind guide plate 101 is configured to be diverted to the lower exhaust port 80a and the rear exhaust port 80b via the exhaust port branching portion 103 and exhausted.
For this reason, the exhaust air guided from the first air guide guide plate 101 is diverted to the lower exhaust outlet 80a and the rear exhaust outlet 80b at the exhaust outlet branching section 103, and is therefore exhausted. In this case, stable air exhaust is possible, and the amount of air exhaust can be secured.

FIG. 6 is a cross-sectional view of the shroud 8 taken along the line VI-VI in FIG. In FIG. 6, the radiator 6 is installed on the right side, and the right crankcase half 30R of the crankcase 30 contacts the left side (see FIG. 3).
FIG. 7 is a left side perspective view of the left side surface of the shroud 8 shown in FIG. 5 as viewed obliquely from the rear side. As shown in the figure, the lower air outlet 80a discharges from the cooling fan 7. A plurality of air guide plates 104 extending in the direction of the exhausted air are erected from the inner peripheral flange portion 85 to promote smooth exhaust air.
The lower air outlet 80a opens downward, and the rear air outlet 80b is located downstream of the lower air outlet 80a via the air outlet branching portion 103 and opens rearward.

The upper air outlet 80c does not open upward and does not exhaust air upward. The upper part of the shroud 8 whose upper part is covered by the second air guide plate 102 is provided with a partition part 87, A notch 87a is provided upward near the two air guide plates 102, and an opening to the left side, that is, the right crankcase half 30R of the crankcase 30 is formed.
That is, the exhaust air flowing along the direction of the exhaust air discharged from the cooling fan 7 through the second vortex chamber 89 formed between the inner peripheral flange portion 85 and the second air guide plate 102 is shroud 8. Is turned leftward through a notch 87a of the partition portion 87 (see FIG. 3), exhausted into the right crankcase half 30R of the crankcase 30, and used for cooling the crankcase 30.

As shown in FIG. 2, an exhaust pipe 45 is connected to the exhaust hole 33 b of the cylinder head 33 of the internal combustion engine 3. The exhaust pipe 45 rotates to the right side below the internal combustion engine 3, and the radiator 6 and the shroud 8. Is connected to an exhaust muffler 46 disposed on the right side of the rear wheel 14.
In order to improve the exhaust gas purification performance, the catalyst 47, which has been conventionally arranged in the muffler 46, is brought into the middle of the exhaust pipe 45 leading to the exhaust muffler 46 as in this embodiment in order to bring the catalyst 47 close to the combustion chamber of the internal combustion engine 3. In some cases, a catalyst internal portion 45a in which a catalyst 47 is internally provided is provided.

FIG. 8 is a right side view of the internal combustion engine 3 portion of the power unit 5 shown in the same direction as FIG. 2, but the shroud 8 portion is generally shown by a cross-section taken along arrow VIII-VIII in FIG. An enclosed cooling fan 7 is also shown.
As shown in FIG. 8, the notch 87 a of the partition 87 at the upper part of the shroud 8 forms an upper exhaust port 80 c that passes into the crankcase 30, and exhaust air from the upper exhaust port 80 c is exhausted into the crankcase 30. Winded.
Further, the rear side exhaust port 80b and the oil level gauge 38 are partially overlapped with each other in the vertical direction and are on the same cross section, and the oil level gauge 38 is positioned in the vertical and horizontal directions behind the rear side exhaust port 80b in the vehicle longitudinal direction. Are located so as to partially overlap.

Further, the exhausted air from the lower exhaust port 80a is exhausted toward the exhaust pipe 45 passing below the radiator 6 and the shroud 8.
At this time, in this embodiment, as shown in FIG. 8, the catalyst internal portion 45 a provided in the middle of the exhaust pipe 45 reaching the exhaust muffler 46 is partially below the shroud 8 in side view, That is, it arrange | positions under the lower side exhaust port 80a.
9 shows a bottom view of the internal combustion engine 3 portion of the power unit 5 as viewed in the direction of arrows IX-IX in FIG. 8, the catalyst internal portion 45a is viewed from the bottom, partly with the lower exhaust port 80a. It is arranged in a position that does not overlap.
In FIG. 9, the left crankcase half 30L of the crankcase 30 is not shown.

That is, the exhaust pipe 45 leading to the exhaust muffler 46 is provided with a catalyst internal part 45a in which a catalyst 37 is provided in the middle, and at least a part of the catalyst internal part 45a is disposed below the shroud 8 in a side view. At the same time, at least a part of the catalyst internal portion 45a is disposed at a position that does not overlap the lower exhaust port 80a in the bottom view, so that the exhaust pipe 45 is cooled and the catalyst 47 is also cooled. When the catalyst internal portion 45a is arranged so as to block the lower side of the lower exhaust port, the exhaust air does not flow efficiently. Therefore, at least a part of the catalyst internal portion 45a in the lower view is seen from the bottom view. By arranging it at a position that does not overlap with the air vent 80a, the exhaust pipe 45 and its catalyst internal portion 45a are cooled, and the exhaust air can be exhausted without being blocked by the catalyst internal portion 45a. ing.

In this way, in the structure in which the exhaust pipe 45 and the catalyst internal portion 45a are arranged below the shroud 8, there is a possibility that the exhaust air from the shroud 8 cannot be efficiently exhausted by the catalyst internal portion 45a. Therefore, as in the present embodiment, the air exhaust port 80 may be formed on the vehicle rear side or the upper side of the shroud 8, which is effective.

Further, the exhaust from the rear side exhaust port 80b is exhausted toward the rear side of the vehicle.
As shown in FIG. 8 and as described above, the oil level gauge 38 provided in the crankcase 30 is positioned behind the rear side exhaust port 80b in the vehicle front-rear direction so that the vertical and horizontal positions partially overlap. . This is as shown in FIG. 9 in which the left and right positions partially overlap each other.
Therefore, as shown in FIG. 10 which is a rear sectional view of the internal combustion engine 3 portion of the power unit 5 as viewed in the direction of arrows XX in FIG. 8, at least a part of the rear side air exhaust port 80b is oil in the rear view. Therefore, at least a part of the rear side exhaust port 80b is covered from behind by the oil level gauge 38, and it is difficult for foreign matter to enter the shroud 8 from the rear side exhaust port 80b. be able to.

The above-described embodiment is an aspect of the cooling device for a straddle-type vehicle internal combustion engine of the present invention, and the present invention naturally includes various aspects within the scope of the present invention.
For example, the straddle-type vehicle is not limited to the motorcycle according to the present embodiment, but also includes a three-wheel and a four-wheel buggy. The internal combustion engine is not limited to the unit swing type power unit, and the crankshaft is arranged in the vehicle width direction. If the cooling fan is arranged at the end of the crankshaft and a shroud (fan cover) is provided between the opposed radiator and the radiator, the cooling of the internal combustion engine for the straddle-type vehicle of the present invention Applicable equipment.
For convenience of explanation, the left and right arrangements of the devices are described as the arrangement of the present embodiment shown in the drawing, but the same applies even if the left and right arrangements are reversed.

As mentioned above, although the cooling device for the straddle-type vehicle internal combustion engine of the present embodiment has been described, the exhaust structure of the straddle-type vehicle internal combustion engine will be considered below in relation to the present embodiment.
In order to improve the purification performance of exhaust gas, the catalyst 47 which has been conventionally arranged in the exhaust muffler 46 is installed in the middle of the exhaust pipe 45 leading to the exhaust muffler 46 in order to approach the combustion chamber of the internal combustion engine 3. There is.
However, since the catalyst 47 becomes high temperature, when the catalyst 47 is installed in the middle of the exhaust pipe 45, it is required to cool the catalyst 47 efficiently.
Therefore, it is conceivable to dispose the catalyst internal portion 45a of the exhaust pipe 45 below the lower exhaust port 80a of the shroud 8 and cool the catalyst 47 using the exhaust air from the shroud 8.

That is, the crankcase 30 of the internal combustion engine 3 of the motorcycle 1 as a saddle-ride type vehicle is provided with a crankshaft 31 oriented in the vehicle width direction, the cooling fan 7 is provided at the end of the crankshaft 31, and the cooling fan 7 Is a saddle type in which a radiator 6 is provided, a shroud 8 surrounding the cooling fan 7 is provided, and a catalyst internal portion 45 a in which a catalyst 47 is provided in the middle of the exhaust pipe 45 leading to the exhaust muffler 46 is provided. In the exhaust structure of an internal combustion engine for a vehicle, the catalyst internal portion 45a is disposed below the lower exhaust port 80a of the shroud 8 in a side view, and at least a part of the catalyst internal portion 45a is in a lower side in a bottom view. One that overlaps the side air outlet 80a is conceivable.
Thereby, the catalyst 47 installed in the exhaust pipe 45 can be cooled using the exhaust air from the shroud 8.

Further, the shroud 8 may be formed with a rear exhaust port 80b on the vehicle rear side in addition to the lower exhaust port 80a.
In that case, even when the catalyst internal portion 45a of the exhaust pipe 45 is disposed directly below the lower exhaust port 80a, the exhaust air from the shroud 8 can be exhausted by providing the rear exhaust port 80b on the rear side of the shroud 8. The wind is not obstructed and the exhaust efficiency can be properly maintained.

Further, the shroud 8 may be formed with an upper air exhaust port 80c on the vehicle upper side in addition to the lower air exhaust port 80a.
In this case, even when the catalyst internal portion 45a of the exhaust pipe 45 is disposed directly below the lower exhaust port 80a, the exhaust air from the shroud 8 is provided by providing the upper exhaust port 80c on the upper side of the shroud 8. Is not hindered, and the exhaust efficiency can be properly maintained.

DESCRIPTION OF SYMBOLS 1 ... Motorcycle ("saddle type vehicle" in this invention), 2 ... Body frame, 3 ... Internal combustion engine, 5 ... Power unit, 6 ... Radiator, 7 ... Cooling fan, 8 ... Shroud, 9 ... Radiator cover, 30 ... Crankcase, 30R ... Right crankcase half, 31 ... Crankshaft, 31a ... Right shaft end, 32 ... Cylinder block, 33 ... Cylinder head, 33b ... Exhaust hole, 36 ... Water pump, 38 ... Oil level gauge, 40 ... ACG, 41 ... outer rotor, 45 ... exhaust pipe, 45a ... catalyst internal part, 46 ... exhaust muffler, 47 ... catalyst, 53 ... thermostat, 60 ... filler neck, 61 ... upper tank, 62 ... lower tank, 63 ... Core part, 66 ... Small assembly unit, 80 ... Exhaust port, 80a ... Lower exhaust port, 80b ... Rear exhaust port, 80c ... Upper exhaust port, 85 ... Inner flange, 85a ... Circular opening, 86 ... Partition plate, 87 ... partition part, 87a ... notch part, 88 1st vortex chamber, 89 ... 2nd vortex chamber, 101 ... 1st wind guide plate, 102 ... 2nd wind guide plate, 103 ... Air exhaust branching part, 104 ... Wind guide plate, C ... (of cooling fan 7) ) Rotation axis, R ... Rotation direction (of cooling fan 7)

Claims

The crankcase (30) of the water-cooled internal combustion engine (3) of the saddle riding type vehicle (1) is provided with a crankshaft (31) oriented in the vehicle width direction, and a centrifugal type is provided at the end of the crankshaft (31). A cooling fan (7) is provided, and a radiator (6) is provided facing the upstream side of the cooling fan (7) in the flow direction of the cooling air, and a shroud (8) surrounding the cooling fan (7) In the cooling structure of a straddle-type vehicle internal combustion engine provided with
A first wind guide plate (101) and a second wind guide plate (102) are provided on the outer periphery of the shroud (8) according to the rotation direction (R) of the cooling fan (7). Each space (88) formed by the first air guide guide plate (101) and the second air guide guide plate (102) is formed so as to increase the radial width from the rotational axis (C) of (7). , 89) are connected to the exhaust port (80) for discharging the exhaust air from the cooling fan (7) on the side where the radial width is enlarged,
The first air guide guide plate (101) and the second air guide guide plate (102) are disposed to face each other across the rotation axis (C) of the cooling fan (7). A cooling structure for an internal combustion engine for a straddle-type vehicle.
The first air guide plate (101) and the second air guide plate (102) are each 90 degrees or more and 180 degrees or less around the rotation axis (C) of the cooling fan (7). The cooling structure for an internal combustion engine for straddle-type vehicles according to claim 1, wherein the cooling structure is formed in an angle range (α1, α2).
The air outlet (80) of the shroud (8) includes a lower air outlet (80a), a rear air outlet (80b), and an upper air outlet (80c),
The lower air outlet (80a) is arranged to exhaust air toward the exhaust pipe (45),
The rear side air exhaust port (80b) is arranged to exhaust air toward the rear side of the vehicle,
The cooling of the internal combustion engine for straddle-type vehicles according to claim 1 or 2, wherein the upper exhaust port (80c) is disposed so as to be exhausted into the crankcase (30). Construction.
The first wind guide plate (101) is formed on the vehicle front side of the shroud (8), and is rotated by the first wind guide plate (101) in the rotational direction (R) of the cooling fan (7). The formed space (88) has a downstream side continuous to the lower exhaust port (80a) and the rear exhaust port (80b),
The second wind guide plate (102) is formed on the vehicle rear side of the shroud (8), and is rotated by the second wind guide plate (102) in the rotation direction (R) of the cooling fan (7). The cooling structure for an internal combustion engine for straddle-type vehicles according to claim 3, wherein the formed space (89) is continuous with the upper air exhaust port (80c) at the downstream side thereof.
An exhaust outlet branching portion (103) is formed between the lower exhaust outlet (80a) and the rear exhaust outlet (80b), and the exhaust air guided from the first air guide plate (101) is 5. The apparatus according to claim 4, wherein the air is diverted to the lower air outlet (80 a) and the rear air outlet (80 b) through the air outlet branching portion (103). A cooling structure for an internal combustion engine for a straddle-type vehicle as described.
The rear rear exhaust port (80b) at least partially overlaps with an oil level gauge (38) provided in the crankcase (30) in rear view. A cooling structure for an internal combustion engine for a saddle-ride type vehicle according to claim 1.
The exhaust pipe (45) leading to the exhaust muffler (46) is provided with a catalyst internal part (45a) in which a catalyst (47) is provided in the middle, and the catalyst internal part (45a) is at least in a side view. A portion is located below the shroud (8);
The catalyst internal portion (45a) is disposed at a position where at least a part of the catalyst internal portion (45a) does not overlap the lower exhaust port (80a) when viewed from below. A cooling structure for an internal combustion engine for a saddle-ride type vehicle according to item 2.