Installation structure of air controller

Abstract

To install an air controller below a fuel tank without impairing merchantability of a vehicle.SOLUTION: An air controller (71) controls supply of secondary air from an air cleaner to an exhaust passage of an engine (20). A cylinder head (23) is located at an upper part of the engine and a cylinder head cover (24) is installed above the cylinder head. A fuel tank (34) is installed above the cylinder head cover. The air controller is installed below the fuel tank and at the side of the cylinder head cover.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to an installation structure for an air control device. [Background technology]

[0002] A secondary air supply device that promotes the combustion of unburned gas in the exhaust gas is mounted on the engine for the purpose of reducing air pollutants. In the secondary air supply device, a passage for secondary air extends from an air cleaner to an exhaust port of the engine, and an air control device is attached midway along this passage. The air control device controls the secondary air flowing toward the exhaust port, and the secondary air is supplied to the exhaust port to re-burn the unburned gas in the exhaust gas. As a straddle-type vehicle equipped with this type of secondary air supply device, one in which an air control device is installed above the engine has been proposed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-119482 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the model described in Patent Document 1, a fuel tank is installed above the engine in addition to the air control device, and the bottom of the fuel tank may be recessed so as not to interfere with the air control device. In this case, the tank capacity is reduced by the amount that the bottom of the fuel tank is recessed. It is possible to move the fuel tank upward to avoid the air control device, or to inflate the tank by the amount that the bottom of the tank is recessed, but this raises the problem of lowering marketability by raising the center of gravity of the vehicle and the seat height.

[0005] The present invention has been made in consideration of the above points, and has an object to provide an air control device installation structure that allows the air control device to be installed below a fuel tank without compromising marketability. [Means for solving the problem]

[0006] One embodiment of the present invention provides an installation structure for an air control device that controls the supply of secondary air from an air cleaner to an exhaust passage of an engine, and solves the above-mentioned problems by providing an air control device having a cylinder head located on the top of the engine, a cylinder head cover installed on the cylinder head, a fuel tank installed above the cylinder head cover, and the air control device installed below the fuel tank and to the side of the cylinder head cover. Effect of the Invention

[0007] According to an installation structure for an air control device according to one aspect of the present invention, the air control device is installed in the dead space below the fuel tank and to the side of the cylinder head cover. By installing the air control device by effectively utilizing the dead space, it is not necessary to change the shape or layout of the fuel tank to ensure installation space for the air control device. The air control device can be installed below the fuel tank without making design changes that would reduce the marketability of the fuel tank, such as reducing the tank capacity or moving the fuel tank upward. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a right side view of the saddle-type vehicle of the present embodiment. [Diagram 2] FIG. 2 is a right side view of the engine and its periphery according to the present embodiment. [Diagram 3] FIG. 2 is a top view of the periphery of the engine according to the embodiment. [Figure 4] FIG. 2 is a front view of the fuel tank and its surroundings according to the embodiment. [Diagram 5] 5 is a cross-sectional view of the fuel tank periphery taken along line AA in FIG. 4. [Figure 6]FIG. 2 is a right side view of the upper portion of the engine and its surroundings according to the present embodiment. [Figure 7] FIG. 7 is a cross-sectional view of the upper portion of the engine periphery taken along line BB in FIG. 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] An air control device according to one embodiment of the present invention controls the supply of secondary air from an air cleaner to an exhaust passage of an engine. In the installation structure of the air control device, a cylinder head is located on the top of the engine, a cylinder head cover is installed on the cylinder head, and a fuel tank is installed above the cylinder head cover. The air control device is installed in dead space below the fuel tank and to the side of the cylinder head cover. By installing the air control device by effectively utilizing the dead space, it is not necessary to change the shape or layout of the fuel tank to ensure installation space for the air control device. The air control device can be installed below the fuel tank without making design changes that would reduce marketability, such as reducing the tank capacity of the fuel tank or moving the fuel tank upward. EXAMPLES

[0010] The saddle riding vehicle of this embodiment will be described below with reference to the accompanying drawings. Fig. 1 is a right side view of the saddle riding vehicle of this embodiment. In the following drawings, the arrow Fr indicates the front of the vehicle, the arrow Re indicates the rear of the vehicle, the arrow L indicates the left side of the vehicle, and the arrow R indicates the right side of the vehicle.

[0011] As shown in Fig. 1, the saddle-type vehicle 1 is configured by mounting various parts such as an engine 20 and an electrical system on a body frame 10. A pair of main frames 12 extend diagonally downward and rearward from a head pipe 11 (see Fig. 4) of the body frame 10, and the rear portions of the pair of main frames 12 are bent downward to form a pair of body frames 13. A down frame 14 extends downward from the head pipe 11, and a pair of under frames 15 bent rearward are connected to the lower portion of the down frame 14. The rear ends of the pair of under frames 15 are connected to the lower portions of the pair of body frames 13, so that the body frame 10 is formed into a cradle shape.

[0012] A front fork 31 is supported on the head pipe 11 via a steering shaft (not shown) so as to be steerable. A handlebar 32 is provided on the upper part of the front fork 31, and a front wheel 33 is rotatably supported on the lower part of the front fork 31. A fuel tank 34 is placed on the upper part of the pair of main frames 12, and the main frames 12 and the fuel tank 34 are covered from the sides by a front side cover 41. A seat 42 is installed behind the fuel tank 34, and a seat frame that supports the seat 42 from below is covered from the sides by a rear side cover 43.

[0013] A swing arm 44 is supported by the body frame 13 so as to be able to swing. The swing arm 44 extends rearward from the body frame 13, and a rear wheel 45 is rotatably supported at the rear end of the swing arm 44. The engine 20 is a four-stroke single-cylinder engine, and is suspended inside the body frame 10 via a plurality of suspension brackets. A cylinder assembly, in which a cylinder 22, a cylinder head 23, and a cylinder head cover 24 are layered, is attached to an upper portion of a crankcase 21 of the engine 20. An intake device such as an air cleaner 46 is provided behind the cylinder head 23.

[0014] The saddle riding type vehicle 1 of this embodiment is equipped with a secondary air supply device that promotes the combustion of unburned gas in the exhaust gas. In the secondary air supply device, a passage for secondary air is formed from the air cleaner 46 to the exhaust passage, and an air cut valve (air control device) 71 that controls the supply of secondary air is installed midway along this passage. In this case, if the air cut valve 71 is installed above the engine 20, there is a risk that it will interfere with the fuel tank 34. Therefore, in this embodiment, the air cut valve 71 is installed in a dead space on the side of the cylinder head cover 24 so that the air cut valve 71 does not interfere with the fuel tank 34.

[0015] The installation structure of the air cut valve will be described with reference to Fig. 2 to Fig. 5. Fig. 2 is a right side view of the engine and its periphery in this embodiment. Fig. 3 is a top view of the engine and its periphery in this embodiment. Fig. 4 is a front view of the fuel tank and its periphery in this embodiment. Fig. 5 is a cross-sectional view of the fuel tank and its periphery in Fig. 4 taken along line AA.

[0016] As shown in Fig. 2, a pair of main frames 12 and a down frame 14 are connected to the upper part of the body frame 10 via a reinforcing bridge tube 16. Below the bridge tube 16, a cylinder head 23 at the upper part of the engine 20 and a crankcase 21 at the lower part of the engine 20 are suspended from the body frame 10 by suspension brackets 17-19. A cylinder 22 is installed on the crankcase 21, and a cylinder head 23 is installed on the cylinder 22. A cylinder head cover 24 is installed on the cylinder head 23, and a DOHC type valve train is housed inside the cylinder head 23 and the cylinder head cover 24.

[0017] A clutch cover 25 that covers a clutch (not shown) from the side is attached to the right side of the crankcase 21. A water pump 26 that sends cooling water to the engine 20 is attached in front of the clutch cover 25. An air cleaner 46 is installed at the rear of the engine 20. The air cleaner 46 is connected to the rear side (intake side) of the cylinder head 23 via a throttle body 47 and an intake pipe 48. Air is sent from the air cleaner 46 to the throttle body 47, and after the intake amount is adjusted by the throttle body 47, the air is supplied from the throttle body 47 to an intake port 62 (see FIG. 5) of the cylinder head 23 through the intake pipe 48.

[0018] 2 and 3, an electromagnetic air cut valve 71 is installed on the right side of the cylinder head cover 24 as an air control device for secondary air. A storage section 74 for a reed valve 73 (see FIG. 5) is provided on the front side (exhaust side) of the cylinder head cover 24, and the storage section 74 is closed from above by a reed valve cover 75. A first hose 81 extends from the air cleaner 46 to the air cut valve 71, and a second hose 82 extends from the air cut valve 71 to the reed valve cover 75. An internal flow path extends from the inside of the reed valve cover 75 to the exhaust port 61 (see FIG. 5) of the cylinder head 23.

[0019] Secondary air is sent from the air cleaner 46 to the air cut valve 71 through a first hose 81, the timing of the secondary air introduction is controlled by the air cut valve 71, and the secondary air is sent from the air cut valve 71 into the reed valve cover 75 through a second hose 82. Secondary air is supplied from inside the reed valve cover 75 to the exhaust port 61, and unburned gas in the exhaust gas is re-burned to reduce air pollutants. In addition, the reed valve 73 is installed inside the reed valve cover 75, and the reed valve 73 prevents exhaust gas from flowing back from the exhaust port 61 to the air cleaner 46 side.

[0020] The air cut valve 71 is supported in a floating state on the cylinder head cover 24 via a bracket 83. The bracket 83 is formed into an inverted L shape with a vertical plate portion and a horizontal plate portion, and the vertical plate portion of the bracket 83 is fixed to the upper wall 51 of the cam chain chamber of the cylinder head cover 24. An inverted U-shaped linear member 84 with both ends facing downward is provided on the horizontal plate portion of the bracket 83, and the air cut valve 71 is attached to both ends of the linear member 84. Compared to a configuration in which the air cut valve 71 is supported by the body frame 10, the air cut valve 71 can be installed closer to the cylinder head cover 24.

[0021] In this case, the air cut valve 71 is positioned between the left and right side surfaces 52, 53 of the crankcase 21 in a top view, and more specifically, is positioned between the right side surface 53 of the crankcase 21 and the right side surface 54 of the cylinder head cover 24. Furthermore, in a top view, the air cut valve 71 is positioned rearward of a front end position P1 of the cylinder head cover 24 and forward of a rear end position P2 of the cylinder head cover 24. The air cut valve 71 is brought closer to the cylinder head cover 24 in the left-right direction without interfering with the fuel tank 34 (see FIG. 4). As a result, the second hose 82 extending from the air cut valve 71 to the reed valve cover 75 is shortened.

[0022] 4 and 5, a pair of left and right main frames 12 extend from the head pipe 11 toward the rear of the vehicle, and a fuel tank 34 is installed on the pair of left and right main frames 12 above the cylinder head cover 24. A plug hole 55 for an ignition plug (not shown) is formed in the center of the cylinder head cover 24 and the cylinder head 23. An exhaust camshaft 56 for an exhaust valve (not shown) is installed on the inside of the cylinder head cover 24 and the cylinder head 23, forward of the plug hole 55, and an intake camshaft 57 for an intake valve (not shown) is installed behind the plug hole 55.

[0023] An air cut valve 71 is installed via a bracket 83 below the fuel tank 34 and to the side of the cylinder head cover 24. In a side view, the bracket 83 is positioned between axes C1, C2 which pass through the centers of the exhaust camshaft 56 and the intake camshaft 57 and are parallel to the cylinder axis. In a side view, the reed valve 73 is installed forward of the spark plug hole 55, and is positioned on the axis C1 which passes through the exhaust camshaft 56. In a side view, the air cut valve 71 is installed rearward of the spark plug hole 55, and is positioned on the axis C2 which passes through the intake camshaft 57.

[0024] An exhaust port 61 is formed in the cylinder head 23 below the exhaust camshaft 56, and an intake port 62 is formed in the cylinder head 23 below the intake camshaft 57. An installation space for a reed valve 73 is formed inside a storage portion 74 and a reed valve cover 75 above the exhaust camshaft 56. The front walls of the cylinder head 23 and the cylinder head cover 24 partially protrude in front of the exhaust camshaft 56. A secondary air supply passage 64 is formed inside the protruding portion 63 of the cylinder head 23 and the cylinder head cover 24, extending from the bottom surface of the storage portion 74 to the exhaust port 61.

[0025] The fuel tank 34 is installed above the cylinder head cover 24, but the air cut valve 71 is installed on the side of the cylinder head cover 24 to prevent interference between the fuel tank 34 and the air cut valve 71. The air cut valve 71 is installed further rearward of the vehicle than the reed valve 73, and a second hose 82 is arranged from the reed valve cover 75 on the cylinder head cover 24, passing along the side of the cylinder head cover 24 to the air cut valve 71. By having the second hose 82 pass along the side of the cylinder head cover 24, the length of the second hose 82 can be shortened by using an installation route that avoids the fuel tank 34.

[0026] The layout of the air cut valve will be described with reference to Figures 6 and 7. Figure 6 is a right side view of the upper part of the engine and its periphery in this embodiment. Figure 7 is a cross-sectional view of the upper part of the engine and its periphery taken along line BB in Figure 6.

[0027] 6 and 7, the fuel tank 34 straddles the pair of left and right main frames 12, and the main frames 12 and the bridge tube 16 are covered by the fuel tank 34 from the sides. Both the left and right sides of the bottom surface of the fuel tank 34 are recessed upward, and the main frames 12 and the bridge tube 16 fit into the recesses 35 of the fuel tank 34. An outer portion 36 that covers the main frames 12 from the sides is formed outside the recess 35 of the fuel tank 34 in the left and right direction. The outer portion 36 of the fuel tank 34 extends downward beyond the bridge tube 16 and the center of the bottom surface of the fuel tank 34, and the lower end of the outer portion 36 is located at approximately the same height as the upper surface of the cylinder head cover 24.

[0028] Below the main frame 12 and the bridge tube 16, the cylinder head cover 24 and the outer part 36 of the fuel tank 34 are spaced apart. The air cut valve 71 is installed by effectively utilizing the space between the cylinder head cover 24 and the outer part 36 of the fuel tank 34. In a side view, a part of the air cut valve 71 overlaps the outer part 36 of the fuel tank 34, making the air cut valve 71 less noticeable and improving the appearance. In addition, the operating sound of the air cut valve 71 is blocked by the outer part 36 of the fuel tank 34 and is less likely to reach the driver. When the vehicle rolls over, the air cut valve 71 is protected from impact by the outer part 36 of the fuel tank 34.

[0029] Because the air cut valve 71 is installed in the space below the main frame 12, the fuel tank 34 does not interfere with the air cut valve 71. Because the air cut valve 71 fits in the space below the main frame 12, there is no need to increase the size of the fuel tank 34 in the left-right direction. The air cut valve 71 is located above the mating surface 65 of the cylinder head 23 and the cylinder head cover 24. By moving the air cut valve 71 upward away from the cylinder head 23, which is a heat source, thermal damage to the air cut valve 71, which is an electronic device, is suppressed and the durability of the air cut valve 71 is improved.

[0030] In a cross-sectional view, the center of the bottom surface of the fuel tank 34 is at approximately the same height as the lower surface of the bridge tube 16, and a fuel pump 86 is installed in the center of the bottom surface of the fuel tank 34. The fuel pump 86 is located rearward of the air cut valve 71 (see FIG. 5), and a nipple (part) 87 of the fuel pump 86 protrudes downward from the bottom surface of the fuel tank 34 above the cylinder head cover 24. The upper end 72 of the air cut valve 71 on the side of the cylinder head cover 24 is located higher than the lower end 88 of the nipple 87 above the cylinder head cover 24. The position of the fuel pump 86 is close to the cylinder head cover 24, ensuring a sufficient tank capacity of the fuel tank 34.

[0031] As described above, according to the installation structure of the air cut valve 71 of this embodiment, the air cut valve 71 is installed in the dead space below the fuel tank 34 and to the side of the cylinder head cover 24. By installing the air cut valve 71 by effectively utilizing the dead space, it is not necessary to change the tank shape or tank layout of the fuel tank 34 to ensure installation space for the air cut valve 71. The air cut valve 71 can be installed below the fuel tank 34 without making design changes that would reduce marketability, such as reducing the tank capacity of the fuel tank 34 or moving the fuel tank 34 upward.

[0032] In this embodiment, the air cut valve is installed below the right main frame and on the right side of the cylinder head cover, but the air cut valve may be installed below the left main frame and on the left side of the cylinder head cover.

[0033] In addition, in this embodiment, the air cut valve is provided between the outer portion of the fuel tank and the cylinder head cover, but the air cut valve may be provided below the fuel tank and to the side of the cylinder head cover.

[0034] Further, in this embodiment, a vehicle body frame in which a pair of main frames extend from the head pipe toward the rear of the vehicle has been exemplified, but the structure of the vehicle body frame is not particularly limited.

[0035] Further, in this embodiment, the air cut valve is supported on the cylinder head cover via a bracket, but the air cut valve may be supported on the fuel tank or the vehicle frame via a bracket.

[0036] The installation structure of the air cut valve of this embodiment is not limited to the above-mentioned off-road type saddle-ride vehicle, but may be adopted in other types of saddle-ride vehicles. Note that a saddle-ride vehicle is not limited to all vehicles in which the rider sits astride the seat, but also includes scooter-type vehicles in which the rider does not sit astride the seat.

[0037] As described above, the first embodiment is an installation structure for an air control device (air cut valve 71) that controls the supply of secondary air from the air cleaner (46) to the exhaust passage (exhaust port 61) of the engine (20), in which the cylinder head (23) is located on the top of the engine, the cylinder head cover (24) is installed on the cylinder head, the fuel tank (34) is installed above the cylinder head cover, and the air control device is installed below the fuel tank and to the side of the cylinder head cover. According to this configuration, the air control device is installed in the dead space below the fuel tank and to the side of the cylinder head cover. Since the air control device is installed by effectively utilizing the dead space, it is not necessary to change the shape or layout of the fuel tank to ensure the installation space for the air control device. The air control device can be installed below the fuel tank without making design changes that would reduce the marketability of the fuel tank, such as reducing the tank capacity or moving the fuel tank upward.

[0038] In the second embodiment, in the first embodiment, a pair of left and right main frames (12) extend from the head pipe (11) toward the rear of the vehicle, a fuel tank straddles the pair of left and right main frames, an outer portion (36) is formed on the fuel tank that covers the pair of left and right main frames from the sides, an air control device is installed between the cylinder head cover and the outer portion of the fuel tank, and a part of the air control device overlaps the outer portion of the fuel tank in a side view. According to this configuration, even if the air control device is installed to the side of the cylinder head cover, a part of the air control device is covered from the side by the outer portion of the fuel tank, so that the air control device is less noticeable and the appearance is improved. The operating sound of the air control device is blocked by the outer portion of the fuel tank and is less likely to reach the driver. When the vehicle rolls over, the air control device is protected from impact by the outer portion of the fuel tank.

[0039] In the third embodiment, in the first and second embodiments, a part of the fuel pump (nipple 87) protrudes from the bottom of the fuel tank above the cylinder head cover, and the upper end of the air control device on the side of the cylinder head cover is located higher than the lower end of the fuel pump above the cylinder head cover. With this configuration, the position of the fuel pump is brought closer to the cylinder head cover, and the bottom of the fuel tank can be lowered to ensure a sufficient tank capacity.

[0040] In a fourth aspect, in any one of the first to third aspects, a pair of left and right main frames extend from the head pipe toward the rear of the vehicle, and the air control device is installed below one of the pair of left and right main frames. With this configuration, the fuel tank does not interfere with the air control device below the main frames. Since the air control device fits in the space below the main frames, there is no need to increase the size of the fuel tank in the left-right direction.

[0041] A fifth aspect is any one of the first to fourth aspects, in which the air control device is located above a mating surface (65) between the cylinder head and the cylinder head cover. With this configuration, the air control device is separated from the cylinder head, which is a heat source, thereby suppressing thermal damage to the air control device, which is an electronic device, and improving the durability of the air control device.

[0042] In a sixth aspect, in any one of the first to fifth aspects, the air control device is supported on the cylinder head cover via a bracket (83). With this configuration, the air control device can be brought close to the cylinder head cover without interfering with the fuel tank, and the hose connecting the air control device to the reed valve can be shortened.

[0043] A seventh aspect is any one of the first to sixth aspects, in which a reed valve (73) is provided on the cylinder head cover, and the air control device is provided rearward of the reed valve on the vehicle. With this configuration, a hose is arranged from above the cylinder head cover, passing along the side of the cylinder head cover to the air control device. The hose connecting the reed valve and the air control device can be shortened by an arrangement route that avoids the fuel tank.

[0044] Although the present embodiment has been described, other embodiments may be made by combining the above-described embodiments and modifications in whole or in part.

[0045] In addition, the technology of the present invention is not limited to the above examples, and may be modified, substituted, or altered in various ways without departing from the spirit of the technical idea. Furthermore, if the technical idea can be realized in a different way due to the progress of technology or a different technology derived therefrom, the invention may be implemented using that method. Therefore, the claims cover all embodiments that may be included within the scope of the technical idea. [Explanation of symbols]

[0046] 1: Saddle-type vehicle 10: Body frame 11: Head pipe 12: Mainframe 20: Engine 23: Cylinder head 24: Cylinder head cover 34: Fuel tank 36 :Outer part 46: Air cleaner 61: Exhaust port (exhaust passage) 65:Mating surface 71: Air cut valve (air control device) 73: Reed valve 83: Bracket 86: Fuel pump 87: Nipple (part of the fuel pump)

Claims

1. An installation structure for an air control device that controls the supply of secondary air from an air cleaner to an exhaust passage of an engine, A cylinder head is located at the top of the engine, A cylinder head cover is installed on the cylinder head, A fuel tank is installed above the cylinder head cover, 13. An air control device installation structure, comprising: said air control device installed below said fuel tank and to the side of said cylinder head cover.

2. A pair of main frames extend from the head pipe to the rear of the vehicle. The fuel tank straddles the pair of left and right main frames, The fuel tank is formed with an outer portion that covers the pair of left and right main frames from the sides, 2. The air control device installation structure according to claim 1, wherein the air control device is installed between the cylinder head cover and the outer portion of the fuel tank, and a portion of the air control device overlaps with the outer portion of the fuel tank in a side view.

3. a fuel pump protruding from a bottom surface of the fuel tank above the cylinder head cover; 3. An air control device installation structure as described in claim 1 or claim 2, characterized in that an upper end of the air control device on the side of the cylinder head cover is located higher than a lower end of the fuel pump above the cylinder head cover.

4. A pair of main frames extend from the head pipe to the rear of the vehicle.

3. An installation structure for an air control device according to claim 1 or 2, wherein the air control device is installed below one of the pair of left and right main frames.

5. 3. The installation structure of claim 1, wherein the air control device is located above a mating surface between the cylinder head and the cylinder head cover.

6. 3. The air control device installation structure according to claim 1, wherein the air control device is supported on the cylinder head cover via a bracket.

7. A reed valve is installed on the cylinder head cover, 3. The air control device installation structure according to claim 1, wherein the air control device is installed rearward of the reed valve on the vehicle.

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