Intake structure of a saddle-type vehicle

Abstract

This invention provides an intake structure for a saddle-type vehicle that can stably draw in air under pressurized conditions at the air cleaner inlet. [Solution] In an intake structure that pressurizes intake air using a center duct, the center duct 51 has a bent portion 60 from the duct inlet 51A to the air cleaner inlet 52A, and has an opening 61 at least in the vertical direction behind the bent portion 60.

Description

Technical Field

[0001] The present invention relates to an intake structure for a saddle-ridden vehicle.

Background Art

[0002] Patent Document 1 discloses an intake structure for a saddle-ridden vehicle that performs intake pressurization using a center duct. The vehicle body frame of the saddle-ridden vehicle is covered with a cowling, and the inlet of the center duct opens at the front end of the cowling. The center duct extends rearward of the vehicle body, for example, avoiding the left and right front forks of the head pipe, and is connected to the air cleaner inlet.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of Invention

Problem to be Solved by the Invention

[0004] However, in the conventional art, since the center duct is provided with a bent portion to avoid the left and right front forks and the like, there is a risk that the intake-pressurized air will separate at the bent portion, making it impossible to stably intake air to the air cleaner inlet. An object of the present invention is to provide an intake structure for a saddle-ridden vehicle that can stably intake air to an air cleaner inlet.

Means for Solving the Problem

[0005] In the intake structure for a saddle-ridden vehicle that performs intake pressurization using a center duct according to the present invention, the center duct includes a bent portion from the duct inlet to the air cleaner inlet, and is provided with an opening on at least one of the upper and lower sides behind the bent portion. Furthermore, the intake structure of the present invention is an intake structure for a saddle-type vehicle that pressurizes intake air by a center duct, wherein the center duct has a bent portion from the duct inlet to the air cleaner inlet, and has an opening above the front end of the bent portion. [Effects of the Invention]

[0006] According to the present invention, stable air intake is possible at the air cleaner inlet. [Brief explanation of the drawing]

[0007] [Figure 1] This is a side view of a saddle-type vehicle according to an embodiment of the present invention. [Figure 2] This is a side view showing the center duct located within the cowling. [Figure 3] This is a perspective view of the center duct from below. [Figure 4] This is a plan view showing the center duct and air cleaner connected. [Figure 5] This is a side view showing the center duct and air cleaner connected. [Figure 6] This is a conceptual diagram simulating the intake airflow within the center duct when slits are provided. [Figure 7] This is a comparison diagram showing the case where no slits are provided. [Figure 8] This is a conceptual diagram simulating the intake airflow within the center duct when slits are provided. [Figure 9] This is a comparison diagram showing the case where no slits are provided. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described below with reference to the drawings. In the description, directions such as front, back, left, right, and up and down refer to directions relative to the vehicle body unless otherwise specified. In each figure, the symbol FR indicates the front of the vehicle body, the symbol UP indicates the top of the vehicle body, and the symbol LH indicates the left side of the vehicle body.

[0009] [Embodiment] Figure 1 is a side view of a saddle-type vehicle 10 according to an embodiment of the present invention. The saddle-type vehicle 10 is a vehicle that comprises a body frame 11, a power unit 12 supported by the body frame 11, a front fork 14 that supports the front wheel 13 in a steerable manner, a swing arm 16 that supports the rear wheel 15, and a seat 17 for the rider. The saddle-type vehicle 10 is a vehicle in which the occupant sits straddling a seat 17. The seat 17 is located above the rear of the vehicle frame 11.

[0010] The vehicle frame 11 comprises a head pipe 18 located at the front end of the vehicle frame 11, a front frame 19 located behind the head pipe 18, and a rear frame 20 located behind the front frame 19. The front end of the front frame 19 is connected to the head pipe 18. The seat 17 is supported by the rear frame 20.

[0011] The front fork 14 is supported by a head pipe 18 so that it can be steered left and right. The front wheel 13 is supported by an axle 13a located at the lower end of the front fork 14. A steering handle 21, which is held by the rider, is attached to the upper end of the front fork 14.

[0012] The swingarm 16 is supported by a pivot shaft 22 which is supported by the vehicle frame 11. The pivot shaft 22 is an axis that extends horizontally in the vehicle width direction. The pivot shaft 22 is inserted through the front end of the swingarm 16. The swingarm 16 swings up and down around the pivot shaft 22. The rear wheel 15 is supported by an axle 15a located at the rear end of the swing arm 16.

[0013] The power unit 12 is positioned between the front wheels 13 and the rear wheels 15 and is supported by the vehicle frame 11. The power unit 12 is an internal combustion engine. The power unit 12 includes a crankcase 23 and a cylinder portion 24 that accommodates a reciprocating piston. An exhaust device 25 is connected to an exhaust port of the cylinder portion 24. The output of the power unit 12 is transmitted to the rear wheel 15 by a driving force transmission member that connects the power unit 12 and the rear wheel 15.

[0014] The saddle-type vehicle 10 further includes a front fender 26 that covers the front wheel 13 from above, a rear fender 27 that covers the rear wheel 15 from above, a step 28 on which an occupant places their feet, and a fuel tank 29 that stores fuel used by the power unit 12. The front fender 26 is attached to the front fork 14. The rear fender 27 and the step 28 are disposed below the seat 17. The fuel tank 29 is supported by the vehicle body frame 11.

[0015] In the vehicle body frame 11 of the present embodiment, the left and right front forks 14 are located on both sides of the head pipe 18, the upper portions of the front forks 14 are connected by a top bridge 71, and the vertically intermediate portions of the front forks 14 are connected by a bottom bridge 72. The front frame 19 has a pair of left and right main frame portions 19a extending rearward and downward from the head pipe 18, a pivot frame portion 19b extending downward from the rear end of the main frame portion 19a, and a pair of left and right down frame portions 19c extending downward from the front end portion of the main frame portion 19a.

[0016] A unit hanger 19c1 that supports the front portion of the power unit 12 is provided at the lower end portion of the down frame portion 19c. A unit support portion 19a1 that supports the upper rear portion of the power unit 12 is provided at the rear end portion of the main frame portion 19a. A unit support portion 19b1 that supports the rear portion of the power unit 12 is provided at the lower end portion of the pivot frame portion 19b.

[0017] The power unit 12 is supported on the front frame 19 by the unit hanger 19c1 and the unit support parts 19a1 and 19b1. In this embodiment, the power unit 12 is an internal combustion engine. Hereinafter, the power unit 12 will be referred to as the engine 12. The engine 12 is equipped with a cylinder section 24, and an intake system (not shown) is attached to the cylinder section 24. The intake system, although not shown in the illustration, includes an intake box, a throttle body located inside the intake box, a fuel injector, and the like.

[0018] The transmission 23b, located in the crankcase 23 of the engine 12, includes an output shaft 23b1 that protrudes laterally. A drive sprocket 31 is fixed to the output shaft 23b1. An endless drive chain 32 is wrapped around the drive sprocket 31. The drive chain 32 extends toward the rear wheel 15 and is wrapped around a driven sprocket 33 located on the rear wheel 15. This transmits rotational force as driving force from the engine 12 to the rear wheel 15.

[0019] The rear wheel 15 is rotatably supported at the rear end of the swing arm 16. The front end of the swing arm 16 is pivotably supported at the pivot frame portion 19b via a pivot shaft 22.

[0020] A cushion unit 35 is attached to the swingarm 16. More specifically, a cushion mounting portion 16a is formed on the front upper part of the swingarm 16. The upper end of the cushion unit 35, which extends in the vertical direction, is pivotably attached to the cushion mounting portion 16a. The lower end of the cushion unit 35 is attached to the lower end of the pivot frame portion 19b via a link mechanism 36 having a first link 36a that extends in the front-rear direction and an inverted triangular second link 36b. A reservoir 35a for storing hydraulic fluid is provided on the upper part of the cushion unit 35. A link mounting portion 16b is formed on the lower part of the swingarm 16, to which the first link 36a is connected.

[0021] The vehicle frame 11 is covered by a cowling 40. A windscreen 41 is supported on the upper front of the cowling 40. A fuel tank 29 is attached to the upper part of the main frame section 19a via a seat cowl 42. A seat 17 is attached to the seat cowl 42.

[0022] [First embodiment of intake structure] Figure 2 is a side view showing the center duct 51 located inside the cowling 40, Figure 3 is a perspective view of the center duct 51 seen from below, Figure 4 is a top view showing the center duct 51 connected to the air cleaner 52, and Figure 5 is a side view showing the center duct 51 connected to the air cleaner 52.

[0023] As shown in Figure 2, an intake opening 50 for taking in airflow is formed at the center of the front end of the cowling 40 in the vehicle width direction, and the inlet 51A of the center duct 51 is connected to the intake opening 50. The center duct 51 extends diagonally upward toward the rear of the vehicle body, reaching the vicinity of the head pipe 18. The center duct 51 has a constricted section 53 that passes between the left and right front forks 14 located on both sides of the head pipe 18, and the constricted section 53 passes between the top bridge 71 and the bottom bridge 72. In other words, the center duct 51 extends toward the rear of the vehicle body, avoiding the head pipe 18.

[0024] As shown in Figures 3 and 4, a branching section 55 is continuous at the rear end of the constricted section 53. The branching section 55 branches to the left and right in the width direction behind the head pipe 18. Hereinafter, the right side of the vehicle body will be referred to as the right duct 56, and the left side of the vehicle body as the left duct 57. The branching section 55 is located below the fuel tank 29. Between the right duct 56 and the left duct 57, although not shown in the diagram, the fuel piping system for the fuel tank 29 is routed, and the fuel piping system is connected to the engine 12. In other words, the center duct 51 branches off to avoid the fuel piping system of the fuel tank 29 and extends to the rear of the vehicle. As shown in Figure 5, each duct 56, 57 is formed to extend diagonally upward from the rear of the vehicle body and is connected to the inlet 52A of the air cleaner 52.

[0025] As shown in Figure 2, the center duct 51 is provided with a bent portion 60 at the rear end of the constricted portion 53 in order to pass between the top bridge 71 and the bottom bridge 72. As shown in Figure 3, the bent portion 60 is formed between the inlet (duct inlet) 51A of the center duct 51 and the inlet (air cleaner inlet) 52A of the air cleaner 52.

[0026] The bent portion 60 behind the constricted portion 53 is formed at the inlets of the right duct 56 and the left duct 57, and a slit 61 communicating with the outside is formed at the lower end of each inlet of the right duct 56 and the left duct 57. The slit 61 is formed below the rear end of the bent portion 60 behind the constricted portion 53. The slit 61 extends in the width direction of the vehicle body and is provided in multiples at intervals in the front-rear direction of the vehicle body. Note that there may be only one slit 61. Slit 61 is an example of an opening. The opening is not limited to slit 61; the shape of the opening is not limited as long as it is a hole that communicates with the outside.

[0027] Figure 6 is a conceptual diagram simulating the intake airflow within the center duct 51 when the slit 61 is provided. Figure 7 is a comparative diagram when the slit 61 is not provided. In each figure, the shaded area indicates the state of the intake airflow. In the comparison diagram of Figure 7, which does not include the slit 61, the intake airflow (arrow A) within the center duct 51 separates at the rear end of the bent portion 60 behind the constricted portion 53. This separation phenomenon causes the intake airflow at the rear end of the bend 60 in the center duct 51 to concentrate upwards within the duct, making it difficult for air to flow downwards. In other words, the separation phenomenon reduces the actual passage area α within the duct, increases the flow velocity, and increases the pressure loss of the intake airflow. This reduces the ram pressure efficiency.

[0028] As shown in Figure 6, when a slit 61 is provided below the rear end of the bent portion 60 behind the constricted portion 53, the air in the separation region is drawn out to the outside through the slit 61. According to this, the intake airflow (arrow A) does not concentrate in the upper part of the duct, but flows almost evenly using the entire upper and lower area as shown in the figure, resulting in an intake airflow that effectively utilizes the entire passage area β inside the duct. As a result, the flow velocity of the intake airflow inside the duct decreases, the pressure loss of the intake airflow is reduced, and stable intake of air can be achieved at the inlet 52A of the air cleaner 52. This improves the ram pressure efficiency.

[0029] The position of the slit 61 is not limited to below the rear end of the bent portion 60 behind the constricted portion 53. It can be any position that effectively suppresses airflow separation within the duct. For example, if airflow separation occurs above the rear end of the bent portion 60, the slit 61 is provided above the rear end of the bent portion 60. The size of the slit 61 is determined considering the loss of air flow out of the slit 61. The size of the slit 61 is determined so that the effect of suppressing separation outweighs the outflow loss. Simulation results have shown that even if there is an outflow loss from the slit 61, the effect of suppressing separation outweighs it.

[0030] As described above, according to the first embodiment, in the intake structure of a saddle-type vehicle 10 that pressurizes intake air by a center duct 51, the center duct 51 is provided with a bent portion 60 from the duct inlet 51A to the inlet 52A of the air cleaner 52, and a slit 61 is provided in the vertical direction downward behind the bent portion 60. If fluid separation occurs in the vertical direction upward behind the bent portion 60 due to the shape of the center duct 51, a slit 61 is provided in the vertical direction upward behind the bent portion 60. With this configuration, the air in the separation region is drawn out to the outside through the slit 61, and the intake airflow effectively utilizes the entire passage area within the duct. This reduces the flow velocity of the intake airflow in the duct, lowers the pressure loss in the intake airflow, and improves ram pressure efficiency. As a result, stable intake of air can be achieved at the inlet 52A of the air cleaner 52.

[0031] In the first embodiment, the center duct 51 has a constricted portion 53 that passes between the left and right front forks 14 of the head pipe 18, and a slit 61 is provided below the rear end of the bent portion 60 behind the constricted portion 53. With this configuration, a slit 61 is provided below the rear end of the bent portion 60, creating a pressure difference at the intake air separation point and suppressing separation. This reduces the flow velocity of the intake air flow in the duct, lowers the pressure loss of the intake air flow, and improves the ram pressure efficiency. As a result, stable intake of air can be achieved at the inlet 52A of the air cleaner 52.

[0032] In the first embodiment, the center duct 51 is branched to the left and right in the width direction behind the head pipe 18, and the branched portion 55 is provided with a slit 61. The branch section 55 has a right duct 56 and a left duct 57, and the slits 61 are formed at the lower ends of the inlets of the right duct 56 and the left duct 57. With this configuration, slits 61 are provided at the lower ends of the inlets of the right duct 56 and left duct 57, which have narrowed duct diameters. This reduces the flow velocity of the intake airflow where the ram pressure is high, lowers the pressure loss of the intake airflow, and improves the ram pressure efficiency. As a result, stable intake of air can be achieved at the inlet 52A of the air cleaner 52.

[0033] In the first embodiment, one or more slits 61 are provided in the front-to-back direction. The total opening area of ​​the slit 61 can be determined by considering the loss of air outflow from the slit 61, such that the effect of suppressing separation outweighs the outflow loss.

[0034] [Second embodiment of intake structure] Figure 8 is a conceptual diagram simulating the intake airflow within the center duct 51 when the slit 161 is provided. Figure 9 is a comparative diagram when the slit 161 is not provided. In each figure, the shaded area indicates the state of the intake airflow.

[0035] As shown in the conceptual diagram in Figure 8, a space S is left in the lower area near the inlet 51A of the center duct 51, and components (not shown) are placed in space S. In such a case, the center duct 51 is bent upward from near the inlet 51A to avoid a component (not shown), and after avoiding the component (not shown), it extends to the rear of the vehicle body and passes between the top bridge 71 and the bottom bridge 72. That is, the center duct 51 has a bent portion 160 at the upper part near the inlet 51A. Furthermore, a slit 161 is provided above the front end of the bent portion 160. The slit 161 extends in the width direction of the vehicle body and is provided in multiples at intervals in the front-rear direction of the vehicle body (see Figure 3). Note that there may be just one slit 161.

[0036] In the comparison diagram of Figure 9, which does not include the slit 161, the intake airflow (arrow A) within the center duct 51 separates at the rear end of the bent section 160. This separation phenomenon causes the intake airflow at the rear end of the bend 160 in the center duct 51 to concentrate in the lower part of the duct, making it difficult for air to flow upwards. In other words, the separation phenomenon occurring in the upper part of the duct reduces the actual passage area within the duct, increases the flow velocity, and increases the pressure loss of the intake airflow. This reduces ram pressure efficiency.

[0037] As shown in Figure 8, if a slit 161 is provided above the front end of the bent portion 160, the air in the separation region is drawn out through the slit 161. According to this design, the intake airflow (arrow A) does not concentrate in the lower part of the duct, but flows almost uniformly using the entire upper and lower area as shown in the diagram, resulting in an intake airflow that effectively utilizes the entire passage area within the duct. This reduces the flow velocity of the intake airflow within the duct, lowers the pressure loss of the intake airflow, and allows for stable intake of air to the inlet 52A of the air cleaner 52. This improves ram pressure efficiency.

[0038] The location where the slit 161 is provided can be any location that can effectively suppress the separation of airflow within the duct, and is not limited to behind the bent portion 160.

[0039] In the second embodiment, in the intake structure of a saddle-type vehicle 10 that pressurizes intake air by a center duct 51, a bent portion 160 is provided from the inlet 51A of the center duct 51 to the inlet 52A of the air cleaner 52, and a plurality of slits 161 are provided above the front end of the bent portion 160. With this configuration, if airflow separation occurs above the front end of the bent portion 160 provided in the center duct 51, the flow velocity of the intake airflow in the duct decreases, reducing the pressure loss of the intake airflow and improving the ram pressure efficiency. This allows for stable intake of air into the inlet 52A of the air cleaner 52.

[0040] [Other embodiments] The embodiments described above represent only one aspect of the present invention and can be modified and applied as needed without departing from the spirit of the invention. For example, if the center duct 51 has multiple bends, the slit 61 may be provided in the bend that provides the highest peeling suppression effect, or the slit 61 may be provided in multiple bends. In this case, the total opening area of ​​the bend is determined considering the outflow loss from the slit 61, such that the peeling suppression effect outweighs the outflow loss.

[0041] [Configurations supported by the above embodiment] The above embodiment supports the following configuration.

[0042] (Configuration 1) An intake structure for a saddle-type vehicle that pressurizes intake air by a center duct, wherein the center duct has a bent portion from the duct inlet to the air cleaner inlet, and has an opening in at least one direction in the vertical direction behind the bent portion. With this configuration, air from the separation region is drawn out through the opening, and the intake airflow effectively utilizes the entire passage area within the duct. As a result, the flow velocity of the intake airflow within the duct decreases, the pressure loss in the intake airflow is reduced, the ram pressure efficiency is improved, and the intake air to the air cleaner inlet becomes stable.

[0043] (Configuration 2) The intake structure for a saddle-type vehicle as described in Configuration 1, wherein the center duct has a constricted portion that passes between the left and right front forks of the head pipe, and the opening is located below the rear end of the bent portion behind the constricted portion. This configuration creates a pressure difference at the intake separation point, thereby suppressing separation. This reduces the flow velocity of the intake airflow within the duct, lowers the pressure loss in the intake airflow, improves ram pressure efficiency, and stabilizes the intake air to the air cleaner inlet.

[0044] (Configuration 3) The intake structure for a saddle-type vehicle according to Configuration 1 or 2, wherein the center duct is branched to the left and right in the width direction behind the head pipe, and the branching portion is provided with the opening. With this configuration, an opening is provided at the branching point where the duct diameter is narrowed, which reduces the flow velocity of the intake airflow where the ram pressure is high, lowers the pressure loss of the intake airflow, and improves the ram pressure efficiency. As a result, the intake air to the air cleaner inlet becomes more stable.

[0045] (Configuration 4) An intake structure for a saddle-type vehicle according to any one of Configurations 1 to 3, wherein one or more openings are provided in the front-rear direction. With this configuration, the total opening area of ​​the opening can be determined such that the effect of suppressing separation outweighs the outflow loss of air from the opening.

[0046] (Configuration 5) An intake structure for a saddle-type vehicle that pressurizes intake air by a center duct, wherein the center duct has a bent section from the duct inlet to the air cleaner inlet, and has an opening above the front end of the bent section. With this configuration, if airflow separation occurs above the front end of the bend, the flow velocity of the intake airflow in the duct decreases, reducing the pressure loss of the intake airflow and improving ram pressure efficiency. As a result, the intake air to the air cleaner inlet becomes stable. [Explanation of Symbols]

[0047] 10. Saddle-type vehicles 12 Engine (Power Unit) 14 Front Fork 18 Headpipe 40 Cowling 51 Center Duct 51A Entrance 52 Air Cleaner 52A Entrance 53 Aperture section 55 Branching point 60, 160 flex points 61, 161 Slit (Opening) 71 Top Bridge 72 Bottom Bridge 56 Right duct 57 Left duct

Claims

1. In an intake structure for a saddle-type vehicle (10) that performs intake pressurization by a center duct (51), The aforementioned center duct (51) is provided with a bent section (60) from the duct inlet (51A) to the air cleaner (52) inlet (52A). The rear of the bent portion (60) is provided with an opening (61) in at least one direction in the vertical direction. Intake structure for a saddle-type vehicle.

2. The center duct (51) is provided with a constricted section (53) that passes between the left and right front forks (14) of the head pipe (18). The opening (61) is provided below the rear end of the bent portion (60) behind the constricted portion (53). The intake structure for a saddle-type vehicle as described in claim 1.

3. The center duct (51) is branched to the left and right in the width direction behind the head pipe (18), The branch portion (55) is provided with the opening (61), The intake structure for a saddle-type vehicle according to claim 2.

4. The aforementioned opening (61) is provided in one or more locations in the front-to-back direction. The intake structure for a saddle-type vehicle as described in claim 1.

5. In an intake structure for a saddle-type vehicle (10) that performs intake pressurization by a center duct (51), The aforementioned center duct (51) is provided with a bent section (160) from the duct inlet (51A) to the air cleaner (52) inlet (52A). An opening (161) is provided above the front end of the bent portion (160). Intake structure for a saddle-type vehicle.

Images