Intake Structure of Internal Combustion Engine

Abstract

Provided is an intake structure for an internal combustion engine. The intake structure comprises an air cleaner 40, an intake passage 90 that introduces intake air from the air cleaner 40 into a combustion chamber 20a of an internal combustion engine 20, a throttle valve 34 that adjusts the flow of air into the combustion chamber 20a, a plurality of intake passages 91, 92 that are downstream of the throttle valve 34, a tumble valve 35 that generates a tumble flow by adjusting the amount of intake air in the plurality of intake passages 91, 92, a tumble valve drive actuator 81 that drives the tumble valve 35, and a throttle valve drive actuator 82 that drives the throttle valve 34. As seen in side view, the tumble valve drive actuator 81 and the throttle valve drive actuator 82 are compactly arranged around an intake pipe 31 on one and the other side thereof.

Description

Technical Field

[0001] The present invention relates to an intake structure of an internal combustion engine.

Background Art

[0002] As a conventional intake structure of an internal combustion engine, an interlocking mechanism is provided that can mechanically interlock and rotate a drive mechanism of a throttle valve driven by a wire and a drive mechanism of a tumble valve. The drive mechanism of the throttle valve, the drive mechanism of the tumble valve, and the interlocking mechanism overlap the intake passage in a side view and are provided on the same side with respect to the intake pipe (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When driving a throttle valve and a tumble valve by an actuator, it is necessary to newly arrange an actuator for driving these valves, and there is a problem that the peripheral mechanism of the intake pipe becomes enlarged.

Means for Solving the Problems

[0005] In an intake structure of an internal combustion engine including an air cleaner, an intake passage for introducing intake air from the air cleaner into a combustion chamber of the internal combustion engine, and a throttle valve for adjusting an air flow rate introduced into the combustion chamber, Located downstream of the throttle valve, there are a plurality of intake passages, a tumble valve that generates a tumble flow by adjusting the intake air volume of the plurality of intake passages, a drive actuator for the tumble valve that drives the tumble valve, and a drive actuator for the throttle valve that drives the throttle valve. The drive actuator for the tumble valve and the drive actuator for the throttle valve are arranged such that in a side view, one is disposed on one side and the other is disposed on the other side with respect to the intake pipe, which is a characteristic of the intake structure of an internal combustion engine.

[0006] According to the above configuration, since the drive actuator for the tumble valve and the drive actuator for the throttle valve are arranged with the intake pipe therebetween in a side view, a compact layout around the intake pipe can be achieved.

[0007] Furthermore, in the present invention, the drive actuator for the tumble valve is arranged such that in a side view, it overlaps at least a part of the throttle valve in the height direction.

[0008] According to the above configuration, since the drive actuator for the tumble valve overlaps at least a part of the throttle valve in the height direction in a side view, a compact layout with reduced height around the intake pipe can be achieved.

[0009] Also, in the present invention, the drive actuator for the throttle valve is arranged such that in a side view, it overlaps at least a part of the tumble valve in the height direction.

[0010] According to the above configuration, since the drive actuator for the throttle valve overlaps at least a part of the tumble valve in a side view, a compact layout with reduced height around the intake pipe can be achieved.

[0011] Furthermore, in the present invention, the drive actuator for the tumble valve is arranged such that in a side view, it overlaps at least a part of the drive actuator for the throttle valve in the height direction.

[0012] According to the above configuration, since the drive actuator for the tumble valve at least partially overlaps with the drive actuator for the throttle valve in a side view, a compact layout with a reduced height around the intake pipe can be achieved.

[0013] The present invention further includes a fuel injection device for spraying fuel into the intake pipe. In a side view, the fuel injection device is arranged on one side of the intake pipe. In a side view, the drive actuator for the tumble valve is characterized in that it at least partially overlaps with the fuel injection device in the height direction.

[0014] According to the above configuration, since the drive actuator for the tumble valve at least partially overlaps with the fuel injection device in a side view, a compact layout with a reduced height around the intake pipe can be achieved.

[0015] Furthermore, the present invention includes a first cover for covering the drive actuator for the tumble valve from the side and a second cover for covering the drive actuator for the throttle valve from the side. In a top view, one of the first cover and the second cover is arranged on one side of the intake pipe, and the other is arranged on the other side.

[0016] According to the above configuration, since the first cover and the second cover are arranged with the intake pipe in between in a top view, a compact layout around the intake pipe can be achieved.

[0017] Furthermore, in a top view, the first cover and the second cover are arranged such that at least a part of them overlaps in the front-rear direction.

[0018] According to the above configuration, since at least a part of the first cover and the second cover overlaps in the front-rear direction in a top view, a compact layout with a reduced front-rear dimension around the intake pipe can be achieved.

Advantages of the Invention

[0019] According to the present invention, the periphery of the intake pipe can be arranged compactly.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0021] Hereinafter, an intake structure of an internal combustion engine according to an embodiment of the present invention will be described with reference to FIGS. 1 to 7. FIG. 1 shows a right side view of a scooter-type motorcycle 1 equipped with an intake structure of an internal combustion engine according to the present embodiment. In the description of this specification, the directions of front, rear, left, right, up, and down shall follow the normal reference with the straight-ahead direction of the motorcycle 1 according to the present embodiment as the front. In the drawings, FR indicates the front, RE indicates the rear, LH indicates the left, RH indicates the right, UP indicates the upper, and DW indicates the lower.

[0022] As shown in FIG. 1, a front part 1F of the vehicle body and a rear part 1R of the vehicle body are connected via a low floor part 1C, and a vehicle body frame F forming the skeleton of the vehicle body generally consists of a down tube 3 and a main pipe 4. That is, the down tube 3 extends downward from the head pipe 2 at the front of the vehicle body 1F. The down tube 3 bends horizontally at the lower end and extends rearward below the floor part 1C. At the rear end, a pair of left and right main pipes 4 are connected. The main pipe 4 forms an inclined part 4a that extends obliquely upward to the rear from the connection part, and the upper part of the inclined part 4a further bends to form a horizontal part 4b that extends substantially horizontally to the rear.

[0023] A storage box 5 and a fuel tank (not shown) are supported between the pair of main pipes 4 in the front-rear direction, and a seat 7 is arranged to cover the upper part of the storage box 5 and the fuel tank. On the other hand, at the front of the vehicle body 1F, a handle 8 is provided above and pivotally supported by the head pipe 2, and a front fork 9 extends downward, and a front wheel 10 is pivotally supported at the lower end thereof.

[0024] A support bracket 11 projects rearward from the front end of the main pipe 4, and a power unit P is swingably connected and supported to the support bracket 11 via a link member 12. Referring to FIG. 3, in the power unit P, a single-cylinder four-stroke air-cooled internal combustion engine 20 is provided at the front part thereof, and a cylinder block 23, a cylinder head 24, and a head cover 25 that are sequentially stacked from a crankcase 22 that pivotally supports a crankshaft 21 in the vehicle width direction are projected forward in a posture greatly inclined forward to a state close to being substantially horizontal. As shown in FIG. 1, the ends of a pair of left and right engine hangers 22h that project forward from the lower part of the crankcase 22 are connected to the link member 12 via a pivot shaft 13.

[0025] Referring to FIG. 6, the crankcase 22 is divided into left and right parts, consisting of a left crankcase part 22L and a right crankcase part 22R. The left crankcase part 22L and the right crankcase part 22R rotatably support a crankshaft 21 oriented in the vehicle width direction via main bearings 21b and 21b, respectively.

[0026] An AC generator 55 is provided on the right shaft portion of the crankshaft 21, and a centrifugal cooling fan 56 is integrally attached to the outer rotor 55r of the AC generator 55. A fan cover 57 that covers the right crankcase portion 22R from the right side houses the centrifugal cooling fan 56 inside. Referring also to FIG. 2, a grill 57g, which is an outside air inlet, is formed in the fan cover 57 so as to face the centrifugal cooling fan 56.

[0027] As shown in FIG. 6, the left crankcase portion 22L extends rearward and also serves as a transmission case portion. A transmission case cover 65 covers the transmission case portion (left crankcase portion) 22L from the left side, and a belt-type continuously variable transmission 60 is disposed inside. A drive chain sprocket 58 is provided on the left shaft portion of the crankshaft 21 adjacent to the main bearing 21b, and a drive pulley 61 of the belt-type continuously variable transmission 60 is provided at the left shaft end portion.

[0028] Power is transmitted to the valve operating mechanism on the cylinder head 24 side by a cam chain 59 wound around the drive chain sprocket 58. Referring to FIGS. 1 and 3, the output shaft of the speed reduction mechanism 64 provided at the rear of the belt-type continuously variable transmission 60 is the rear axle 28a, and a rear wheel 28 is provided on the rear axle 28a. A rear cushion (not shown) is interposed between the upper end of the rear portion that houses the speed reduction mechanism 64 of the transmission case portion 22L and the upper bent portion of the main pipe 4.

[0029] As shown in FIG. 3, a driven pulley 63 of the belt-type continuously variable transmission 60 is pivotally supported on the input shaft 64a of the speed reduction mechanism 64. A belt 62 is wound around the drive pulley 61 provided on the crankshaft 21 and the driven pulley 63 provided on the input shaft 64a of the speed reduction mechanism 64, and the power of the internal combustion engine 20 is transmitted to the driven pulley 63 via the belt 62. The rotation of the driven pulley 63 is transmitted to the input shaft 64a of the speed reduction mechanism 64 via a centrifugal clutch (not shown), decelerated by the speed reduction mechanism 64, and then power is transmitted to the rear wheel 28. As shown in Fig. 6, an outside air intake fan 61F is formed on the pulley half on the left side of the drive pulley 61.

[0030] In the front part 1F of the vehicle body, the vertically oriented parts of the head pipe 2 and the down tube 3 are covered from the front and rear by the front cover 1a and the leg shield 1b. In the floor part 1C, the front and rear oriented part of the down tube 3 is covered by the lower side cover 1c. In the rear part 1R of the vehicle body, the main pipe 4 is covered on the left and right and rear by the body cover 1d.

[0031] The cylinder block 23 and the cylinder head 24 are surrounded by a shroud 70 as shown in Fig. 2, and the shroud 70 is connected to the fan cover 57 on the right side.

[0032] Referring to Fig. 3, the internal combustion engine 20 at the front of the power unit P has a cylinder block 23 protruding forward from the crankcase 22 and a cylinder head 24 protruding further forward, with a head cover 25 superimposed thereon. An intake port 24a is formed on the upper surface side of the cylinder head 24, and an inlet pipe 31 as an intake pipe extends upward from the intake port 24a. An exhaust port 24b is formed on the lower surface side of the cylinder head 24, and an exhaust pipe 51 extends downward from the exhaust port 24b. Also, a spark plug 26 is inserted near the central head cover 25 in the cylinder head 24, and an oxygen concentration sensor 27 is inserted at the location where the exhaust pipe 51 extends.

[0033] An intake device 30 for inhaling outside air and sending it to the internal combustion engine 20 is connected to the intake port 24a of the internal combustion engine 20. The inside of the intake device 30 serves as an intake passage 90 for introducing intake air into the combustion chamber 20a of the internal combustion engine 20. The intake device 30 includes an air cleaner device 40 that takes in and purifies outside air, a connecting tube 36 connected to the air cleaner device 40, a throttle body 33 connected to the downstream side of the connecting tube 36, and an inlet pipe 31 connected to the upstream side of the throttle body 33. These components constitute the intake system.

[0034] On the other hand, as shown in FIG. 5, an exhaust device 50 is connected to the exhaust port 24b of the cylinder head 24. An exhaust pipe 51 that communicates with the exhaust port 24b and extends downward from the lower surface of the cylinder head 24 bends obliquely forward to the left, further bends from the rear to the right, bends from the left side to the right side at the lower part of the crankcase 22, extends rearward, and is connected to a muffler 52 disposed on the right side of the rear wheel 28. A catalytic device 53 is provided in the middle of the exhaust pipe 51, and these components constitute the exhaust system.

[0035] The intake device 30 will be further described. As shown in FIG. 4, the air cleaner device 40 of the intake device 30 has an air cleaner case 41 in which the left and right unpurified chamber cases 42 and the purified chamber case 43 are combined. An air cleaner element 44 is disposed between the unpurified chamber case 42 and the purified chamber case 43, and a partition portion 45 is provided. The air cleaner element 44 is partitioned into an unpurified chamber Ca on the unpurified chamber case 42 side and a purified chamber Cb on the purified chamber case 43 side. As shown in FIG. 3, an air introduction pipe 47 through which running air or the like is taken in is disposed in the unpurified chamber case 42 such that its opening 47a faces forward. The intake air introduced from the opening 47a passes through the air cleaner element 44 in the unpurified chamber Ca and is purified, and then is sent to the purified chamber Cb. The purified chamber Cb of the air cleaner device 40 communicates with the throttle body 33 through an elastically deformable connecting tube 36 made of rubber.

[0036] Referring to FIG. 7, a butterfly throttle valve 34 is provided in the throttle body 33 connected to the connecting tube 36. The throttle valve 34 has a throttle valve body 34b in the shape of a plate that closes the intake passage 90 and is rotatably supported in the throttle body 33 by a throttle valve shaft 34a that is perpendicular to the intake air flow direction F flowing through the intake passage 90 and is oriented substantially horizontally, thereby variably controlling the passage area of the intake passage 90.

[0037] The driving force of the throttle valve driving actuator 82 is transmitted to the throttle valve shaft 34a of the throttle valve 34 via a power transmission mechanism (not shown) to cause rotation. In the present embodiment, a motor is used as the throttle valve driving actuator 82. The throttle valve driving actuator 82 is located below the throttle body 33 and the intake passage 90 in a side view of the vehicle and is disposed on the left side of the vehicle with respect to the intake passage 90. As shown in FIGS. 3 and 4, the left side surface of the throttle valve driving actuator 82 is covered by a second cover 86.

[0038] The downstream side of the throttle body 33 is connected to an inlet pipe 31, and the downstream side of the inlet pipe 31 is connected to the intake port 24a of the cylinder head 24 of the internal combustion engine 20 via a connecting pipe 32.

[0039] The intake passage 90 from the inlet pipe 31 to the curved portion of the intake port 24a via the connecting pipe 32 is partitioned by a partition wall 38 into a first intake passage 91 and a second intake passage 92. With respect to the partition wall 38, the first intake passage 91 is located on the upper side and the second intake passage 92 is located on the lower side. The partition wall 38 is composed of an inlet pipe side partition wall 38a integrally formed with the inlet pipe 31 and an intake port side partition wall 38b integrally formed with the cylinder head 24 in the intake port 24a.

[0040] Of the intake passage 90, the intake passages 90 in the throttle body 33 and the inlet pipe 31 have a substantially circular passage cross-section. The partition wall 38 that vertically partitions this intake passage 90 has both the inlet pipe side partition wall 38a and the intake port side partition wall 38b positioned below the center locus of the maximum vertical width of the intake passage 90 (in the case of this intake passage 90, the center locus of the circle that is the passage cross-section), that is, the passage center line Cp, and the passage cross-sectional area of the upper first intake passage 91 is larger than the passage cross-sectional area of the lower second intake passage 92.

[0041] On the downstream side of the throttle valve 34 in the intake flow direction F of the intake passage 90, near the branch point of the inlet pipe 31 into the first intake passage 91 and the second intake passage 92, a tumble valve 35 is disposed rotatably supported in the throttle body 33 by a tumble valve shaft 35a that is perpendicular to the flow direction F of the intake passage 90 and is oriented substantially horizontally and parallel to the throttle valve shaft 34a.

[0042] The tumble valve 35 can change the ratio of the intake air flowing through the first intake passage 91 and the second intake passage 92 by changing the opening degree of the opening on the upstream side of the first intake passage 91 and diverting the intake air downstream of the throttle valve 34. The power of the tumble valve drive actuator 81 is transmitted to the tumble valve shaft 35a of the tumble valve 35 by a transmission mechanism (not shown) to change the opening degree. In this embodiment, a motor is used as the tumble valve drive actuator 81. The right side surface of the tumble valve drive actuator 81 is covered with a first cover 85 as shown in FIGS. 2 and 4.

[0043] As shown in FIG. 7, an injector 37 as a fuel injection device is mounted so as to face the first intake passage 91 from the upper surface side of the inlet pipe 31 and is attached so as to inject fuel toward the downstream side. Further, the injector 37 is mounted on the upper surface of the throttle body 33 so as to face the intake passage 90 on the downstream side of the throttle valve 34 and is attached so as to inject fuel toward the downstream.

[0044] An electronic control unit (not shown) that controls the internal combustion engine 20 includes intake control means (not shown). The operating state of the internal combustion engine 20 is analyzed, and the tumble valve drive actuator 81, the throttle valve drive actuator 82, and the injector 37 are driven and controlled by the intake control means, and the opening degrees of the tumble valve 35 and the throttle valve are appropriately controlled.

[0045] As shown in FIG. 4, in a top view, the first cover 85 and the second cover 86 are arranged on one side and the other side of the inlet pipe 31, respectively. That is, in a top view of the vehicle, the first cover 85 is disposed on the right side of the passage center line Cp of the intake passage 90, and the second cover 86 is disposed on the left side of the passage center line Cp. Also, the first cover 85 and the second cover 86 are arranged so that at least a part thereof overlaps in the front-rear direction in a top view of the vehicle.

[0046] As shown in FIG. 7, in a side view of the vehicle, the tumble valve drive actuator 81 is arranged on one side of the inlet pipe 31, and the throttle valve drive actuator 82 is arranged on the other side. That is, in a side view of the vehicle, the tumble valve drive actuator 81 is disposed above the passage center line Cp of the intake passage 90, and the throttle valve drive actuator 82 is disposed below the passage center line Cp.

[0047] Furthermore, in a side view of the vehicle, both the tumble valve drive actuator 81 and the throttle valve drive actuator 82 are arranged so as to overlap at least a part of the throttle valve 34 in the height direction. In the present embodiment, in a side view of the vehicle, the throttle valve shaft 34a of the throttle valve 34 overlaps with the tumble valve drive actuator 81 and the throttle valve drive actuator 82 in the height direction. Further, in a state where the throttle valve body 34b is closed, substantially the upper half of the throttle valve body 34b overlaps with the tumble valve drive actuator 81 in the height direction, and substantially the lower half of the throttle valve body 34b overlaps with the throttle valve drive actuator 82 in the height direction.

[0048] Also, in a side view of the vehicle, the tumble valve drive actuator 81 is arranged so as to overlap at least a part of the throttle valve drive actuator 82 in the height direction.

[0049] Furthermore, the injector 37 is arranged on one side with respect to the inlet pipe 31 in a side view of the vehicle, and the tumble valve drive actuator 81 is arranged so as to overlap at least a part of the injector 37 in the height direction in a side view of the vehicle. That is, in a side view of the vehicle, the injector is arranged above the passage center line Cp of the intake passage 90, and further, the tumble valve drive actuator 81 is arranged so as to overlap with the injector 37 provided in the throttle body 33 in the height direction in a side view of the vehicle.

[0050] Since the intake structure of the internal combustion engine according to the embodiment of the present invention is configured as described above, the following effects are obtained.

[0051] The present invention relates to an intake structure of an internal combustion engine, comprising an air cleaner device 40, an intake passage 90 for introducing intake air from the air cleaner device 40 into a combustion chamber 20a of the internal combustion engine 20, and a throttle valve 34 for adjusting the air flow rate introduced into the combustion chamber 20a. Downstream of the throttle valve 34, there are a first intake passage 91 and a second intake passage 92, a tumble valve 35 for generating a tumble flow by adjusting the intake air amounts flowing through the first intake passage 91 and the second intake passage 92, a drive actuator 81 for the tumble valve for driving the tumble valve 35, and a drive actuator 82 for the throttle valve for driving the throttle valve 34. The drive actuator 81 for the tumble valve and the drive actuator 82 for the throttle valve are arranged such that, in a side view, one is disposed above as one side with respect to the inlet pipe 31, and the other is disposed below as the other side. Therefore, the drive actuator 81 for the tumble valve and the drive actuator 82 for the throttle valve are arranged with the inlet pipe 31 interposed therebetween in a side view, so that a compact layout can be achieved around the inlet pipe 31.

[0052] Furthermore, the drive actuator 81 for the tumble valve is arranged such that, in a side view, it overlaps at least a part of the throttle valve 34 in the height direction. Therefore, a compact layout with the height around the inlet pipe 31 suppressed can be achieved.

[0053] Also, the drive actuator 82 for the throttle valve is arranged such that, in a side view, it overlaps at least a part of the tumble valve 35 in the height direction. Therefore, a compact layout with the height around the inlet pipe 31 suppressed can be achieved.

[0054] Furthermore, the drive actuator 81 for the tumble valve is arranged such that, in a side view, it overlaps at least a part of the drive actuator 82 for the throttle valve in the height direction. Therefore, a compact layout with the height around the inlet pipe 31 suppressed can be achieved.

[0055] In addition, an injector 37 is provided as a fuel injection device that sprays fuel into the inlet pipe 31. The injector 37 is arranged above the inlet pipe 31 as one side in a side view. Since the tumble valve drive actuator 81 overlaps with at least a part of the injector 37 in the height direction in a side view, a compact layout with a reduced height around the inlet pipe 31 can be achieved.

[0056] Furthermore, a first cover 85 that covers the tumble valve drive actuator 81 from the side and a second cover 86 that covers the throttle valve drive actuator 82 from the side are provided. Since the first cover 85 and the second cover 86 are arranged on one side and the other side with respect to the inlet pipe 31 in a top view, a compact layout around the inlet pipe 31 can be achieved.

[0057] Moreover, since the first cover 85 and the second cover 86 are arranged such that at least a part overlaps in the front-rear direction in a top view, a compact layout with a reduced front-rear dimension around the inlet pipe 31 can be achieved.

[0058] As described above, the intake structure of the in-vehicle internal combustion engine according to one embodiment of the present invention has been explained. However, the aspects of the present invention are not limited to the above embodiment, and include those implemented in various aspects within the scope of the gist of the present invention. For example, in the embodiment, a motor is used as an actuator for adjusting the throttle valve and the tumble valve to an arbitrary angular position. However, any device that can arbitrarily set the opening position, such as an electromagnet, a diaphragm, a cable, or a piezoelectric element, can be appropriately applied.

Explanation of Reference Numerals

[0059] 1... Motorcycle, 20... Internal combustion engine, 20a... Combustion chamber, 30... Intake device, 31... Inlet pipe, 34... Throttle valve, 35... Tumble valve, 37... Fuel injection device, 40... Air cleaner device, 81... Drive actuator for the tumble valve, 82... Drive actuator for the throttle valve, 85... First cover, 86... Second cover, 90... Intake passage, 91... First intake passage, 92... Second intake passage.

Claims

1. An air cleaner (40), an intake passage (90) for introducing intake air from the air cleaner (40) into a combustion chamber (20a) of an internal combustion engine (20), and a throttle valve (34) for adjusting an air flow rate introduced into the combustion chamber (20a). In an intake structure of an internal combustion engine mounted on a vehicle (1) with a cylinder block (23), a cylinder head (24), and a head cover (25) sequentially stacked and protruded forward in a forward-tilted posture from a crankcase (22) that pivotally supports a crankshaft (21) in the vehicle width direction. Located downstream of the throttle valve (34), a plurality of intake passages (91, 92), a tumble valve (35) for generating a tumble flow by adjusting the intake air amounts of the plurality of intake passages (91, 92), a drive actuator (81) for the tumble valve for driving the tumble valve (35), and a drive actuator (82) for the throttle valve for driving the throttle valve (34). The drive actuator (81) for the tumble valve and the drive actuator (82) for the throttle valve are, when viewed from the left side of the vehicle (1), arranged such that one is disposed above as one side and the other is disposed below as the other side with respect to a passage center line (Cp) of an intake passage (90) composed of an intake pipe (31) and a throttle body (33) extending rearward from the upper surface side of the cylinder head (24). A first cover (85) for covering the drive actuator (81) for the tumble valve from the side and a second cover (86) for covering the drive actuator (82) for the throttle valve from the side. The first cover (85) and the second cover (86) are arranged such that one is disposed on the right side as one side and the other is disposed on the left side as the other side with respect to the intake pipe (31) when viewed from the top of the vehicle (1). An intake structure of an internal combustion engine, characterized in that.

2. The drive actuator (81) for the tumble valve is arranged such that at least a part of it overlaps with at least a part of the throttle valve (34) in the height direction when viewed from the left side of the vehicle (1). The intake structure of the internal combustion engine according to Claim 1, characterized in that.

3. The drive actuator (82) for the throttle valve is arranged such that at least a part of it overlaps with at least a part of the tumble valve (35) in the height direction when viewed from the left side of the vehicle (1). The intake structure of the internal combustion engine according to Claim 1, characterized in that.

4. The drive actuator (81) for the tumble valve is arranged so as to overlap at least a part of the drive actuator (82) for the throttle valve in the height direction in a left side view of the vehicle (1), in the intake structure of the internal combustion engine according to claim 1.

5. The intake pipe (31) is provided with a fuel injection device (37) for spraying fuel, The fuel injection device (37) is arranged on one side of the intake pipe (31) in a left side view of the vehicle (1), The drive actuator (81) for the tumble valve overlaps at least a part of the fuel injection device (37) in the height direction in a left side view of the vehicle (1), in the intake structure of the internal combustion engine according to claim 1.

6. (Deleted)

7. The first cover (85) and the second cover (86) are arranged so that at least a part thereof overlaps in the front-rear direction in a top view of the vehicle (1), in the intake structure of the internal combustion engine according to claim 1.

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