STRADDLED VEHICLE

Abstract

 An internal combustion engine 15 includes a cylinder body 3 extending forward and upward from a crankcase 2, an intake pipe 10 extending upward from a cylinder head 5, and a motor 13 that actuates a throttle valve 11. At least a portion of a fuel injector 12 is arranged forward of the intake pipe 10. At least a portion of the motor 13 is arranged rearward of the intake pipe 10. At least a portion of the fuel injector 12 and at least a portion of the throttle valve 11 are arranged downward relative to an upper end 13a of the motor 13 and upward relative to a lower end 13b of the motor 13.

Description

TECHNICAL FIELD

[0001] The present invention relates to a straddled vehicle having an internal combustion engine including a motor for actuating a throttle valve and a fuel injector.

BACKGROUND ART

[0002] Conventional straddled vehicles including an internal combustion engine of which the cylinder axial line extends forward and upward from the crankcase are known in the art. Internal combustion engines including a motor for actuating a throttle valve arranged in the intake passage and a fuel injector for injecting the fuel into the intake passage are known as such internal combustion engines. For example, FIG 8 of Japanese Patent No. 4916563 describes such an internal combustion engine. With the internal combustion engine described in Japanese Patent No. 4916563, the intake passage extends upward from the cylinder head. The motor is arranged forward of the intake passage, and the fuel injector is arranged rearward of the intake passage.

SUMMARY OF INVENTION

TECHNICAL PROBLEM

[0003] With the internal combustion engine described above, the cylinder axial line extends forward and upward and the intake passage extends upward from the cylinder head. The upstream end portion of the intake passage is connected to the air cleaner, and the downstream end portion of the intake passage is connected to the cylinder head. A portion of the cylinder head and a portion of the cylinder head cover are arranged forward of the intake passage. Therefore, there is no margin of space forward of the downstream end portion of the intake passage. That is, there is no margin of space forward of the connection between the intake passage and the cylinder head.

[0004] In order to appropriately actuate the throttle valve and enhance the responsiveness of the throttle valve, the motor is preferably arranged in the vicinity of the throttle valve. However, the motor for actuating the throttle valve is a relatively large device. With conventional internal combustion engines, since there is no margin of space forward of the downstream end portion of the intake passage, the motor is arranged more toward the upstream end portion. This as a result increases the distance between the throttle valve and the combustion chamber. This has been a limiting factor for reducing the size of the internal combustion engine.

[0005] It is an object of the present invention to reduce the size of a straddled vehicle having an internal combustion engine including a motor for actuating a throttle valve and a fuel injector.

SOLUTION TO PROBLEM

[0006] A straddled vehicle disclosed herein includes an internal combustion engine. The internal combustion engine includes: a crankcase that rotatably supports a crankshaft extending in a vehicle width direction; a cylinder body extending forward and upward from the crankcase; a cylinder formed inside the cylinder body; a cylinder head connected to the cylinder body; an intake port that is formed inside the cylinder head and has an opening facing toward an inside of the cylinder; an intake valve that is supported on the cylinder head and opens/closes the intake port; an intake cam that is rotatably supported on the cylinder head and actuates the intake valve; an intake passage that is formed inside the cylinder head and is connected to the intake port; an intake pipe that is connected to the cylinder head, extends upward from the cylinder head and is connected to the intake passage; a throttle valve that is arranged inside the intake pipe; a fuel injector that has an injection port arranged between the throttle valve and the intake port; and a motor that is linked to the throttle valve and actuates the throttle valve. At least a portion of the fuel injector is arranged forward of the intake pipe. At least a portion of the motor is arranged rearward of the intake pipe. At least a portion of the fuel injector and at least a portion of the throttle valve are arranged downward relative to an upper end of the motor and upward relative to a lower end of the motor.

[0007] With the straddled vehicle, the cylinder body and the cylinder head extend forward and upward from the crankcase, and the intake pipe extends upward from the cylinder head. Therefore, there is no margin of space forward of a portion of the intake pipe that is close to the cylinder head. With the straddled vehicle, however, at least a portion of the motor is arranged rearward of the intake pipe. Therefore, the motor is arranged at a portion of the intake pipe that is close to the cylinder head. With the straddled vehicle, at least a portion of the fuel injector is arranged forward of the intake pipe. This realizes a compact arrangement of the fuel injector, wherein the fuel injector and the motor do not interfere with each other. Furthermore, with the straddled vehicle, at least a portion of the fuel injector and at least a portion of the throttle valve are arranged downward relative to the upper end of the motor and upward relative to the lower end of the motor. Therefore, it is possible to suppress the overall dimension in the up-down direction of the motor, the fuel injector and the throttle valve. Thus, it is possible to reduce the size of the internal combustion engine, and hence to reduce the size of the straddled vehicle.

[0008] According to one preferred embodiment, at least a portion of the intake cam is arranged downward relative to the upper end of the motor and upward relative to the lower end of the motor.

[0009] According to the embodiment described above, since it is possible to suppress the overall dimension in the up-down direction of the motor, the fuel injector, the throttle valve and the cylinder head (specifically, a portion of the cylinder head where the intake cam is provided), it is possible to further reduce the size of the internal combustion engine.

[0010] According to one preferred embodiment, a center of rotation of the intake cam, the injection port of the fuel injector and a center of rotation of the throttle valve are arranged downward relative to the upper end of the motor and upward relative to the lower end of the motor.

[0011] According to the embodiment described above, since it is possible to further suppress the overall dimension in the up-down direction of the motor, the fuel injector, the throttle valve and the cylinder head, it is possible to further reduce the size of the internal combustion engine.

[0012] According to one preferred embodiment, the fuel injector and the throttle valve are arranged rearward relative to a front end of a rotation path of the intake cam and forward relative to a rear end of the motor.

[0013] According to the embodiment described above, since it is possible to suppress the overall dimension in the front-rear direction of the motor, the throttle valve, the fuel injector and the intake cam, it is possible to further reduce the size of the internal combustion engine.

[0014] According to one preferred embodiment, the fuel injector and the throttle valve are arranged rearward relative to the center of rotation of the intake cam and forward relative to a center of the motor.

[0015] According to the embodiment described above, since it is possible to further suppress the overall dimension in the front-rear direction of the motor, the throttle valve, the fuel injector and the intake cam, it is possible to further reduce the size of the internal combustion engine.

[0016] According to one preferred embodiment, the fuel injector and the throttle valve are arranged rearward relative to the center of rotation of the intake cam and forward relative to a center of rotation of the crankshaft.

[0017] According to the embodiment described above, since it is possible to suppress the overall dimension in the front-rear direction of the motor, the throttle valve, the fuel injector and the intake cam, it is possible to further reduce the size of the internal combustion engine.

[0018] According to one preferred embodiment, where a first line is defined as a straight line that passes through a center of rotation of the intake cam and is perpendicular to an axial line of the cylinder and a second line as a straight line that passes through a center of the intake port and is perpendicular to the axial line of the cylinder, the injection port of the fuel injector, a center of the throttle valve and a center of the motor are arranged between the first line and the second line, as the vehicle is seen from the side.

[0019] According to the embodiment described above, it is possible to suppress the overall dimension of the motor, the throttle valve, the fuel injector and the intake cam for the direction along the cylinder axial line. It is possible to further reduce the size of the internal combustion engine.

[0020] According to one preferred embodiment, the injection port of the fuel injector, an entirety of the throttle valve and an entirety of the motor are arranged between the first line and the second line, as the vehicle is seen from the side.

[0021] According to the embodiment described above, it is possible to further suppress the overall dimension of the motor, the throttle valve, the fuel injector and the intake cam for the direction along the cylinder axial line. It is possible to further reduce the size of the internal combustion engine.

[0022] According to one preferred embodiment, a center line of the intake pipe is located rearward relative to a center of rotation of the intake cam and forward relative to a rear end of the motor.

[0023] According to the embodiment described above, the dimension of the intake pipe in the front-rear direction is small. It is possible to further reduce the size of the internal combustion engine.

[0024] According to one preferred embodiment, an angle formed between an axial line of the cylinder and a horizontal line is 45 degrees or more, as the vehicle is seen from the side.

[0025] According to the embodiment described above, since the inclination of the cylinder is large, there is a small space between the cylinder body and the cylinder head and the intake pipe. Therefore, the aforementioned effects, e.g., being able to arrange the motor at a portion of the intake pipe that is close to the cylinder head, are particularly pronounced.

[0026] According to one preferred embodiment, an angle formed between an axial line of the fuel injector and a horizontal line is greater than an angle formed between an axial line of the cylinder and the horizontal line, as the vehicle is seen from the side.

[0027] According to the embodiment described above, the fuel injector is arranged in an attitude that is more along the vertical direction. It is possible to suppress the dimension of the fuel injector in the front-rear direction. Thus, the fuel injector is arranged in a compact arrangement in a small space between the cylinder head and the intake pipe.

[0028] According to one preferred embodiment, the straddled vehicle includes a vehicle frame that supports the internal combustion engine. The vehicle frame includes a side frame that overlaps with at least a portion of the throttle valve, at least a portion of the fuel injector and at least a portion of the motor, as the vehicle is seen from the side.

[0029] With the straddled vehicle, at least a portion of the fuel injector is arranged forward of the intake pipe, and at least a portion of the motor is arranged rearward of the intake pipe. The side frame is arranged sideward of the intake pipe without being interfered by the fuel injector and the motor. According to the embodiment described above, at least a portion of the throttle valve, at least a portion of the fuel injector and at least a portion of the motor are arranged in a compact arrangement sideward of the side frame. It is possible to suppress the overall dimension in the up-down direction of the throttle valve, the fuel injector, the motor and the side frame. Thus, it is possible to reduce the size of the straddled vehicle.

[0030] According to one preferred embodiment, the straddled vehicle includes: a fuel tank arranged rearward relative to the intake pipe; and a fuel hose connected to the fuel tank and the fuel injector. A portion of the fuel hose is arranged sideward of the intake pipe.

[0031] According to the embodiment described above, the fuel hose extends from the fuel tank toward the fuel injector through the side of the intake pipe. Since the motor is arranged rearward of the intake pipe, it is possible to easily avoid the interference between the fuel hose and the motor.

[0032] The straddled vehicle may include an air cleaner case including a connection port to which the intake pipe is connected.

[0033] According to one preferred embodiment, the internal combustion engine includes: a piston arranged in the cylinder; a crank pin provided on the crankshaft; and a connecting rod linked to the piston and the crank pin. At least a portion of the connection port of the air cleaner case, at least a portion of the throttle valve and at least a portion of the motor are located rearward relative to a front end of a rotation path of the crank pin and forward relative to a rear end of the rotation path.

[0034] According to the embodiment described above, since it is possible to suppress the overall dimension in the front-rear direction of the connection port of the air cleaner case, the throttle valve and the motor, it is possible to reduce the size of the straddled vehicle.

[0035] According to one preferred embodiment, at least a portion of the fuel injector is located downward relative to an upper end of the connection port of the air cleaner case and upward relative to a lower end of the connection port.

[0036] According to the embodiment described above, the distance between the connection port of the air cleaner case and the fuel injector in the up-down direction is short. It is possible to reduce the size of the straddled vehicle.

[0037] According to one preferred embodiment, a straight line that passes through a center of the motor and is parallel to an axial line of the cylinder overlaps with the air cleaner case, as the vehicle is seen from the side.

[0038] According to the embodiment described above, the motor is arranged close to the air cleaner case. The motor and the air cleaner case are arranged in a compact arrangement.

[0039] According to one preferred embodiment, the fuel injector is a slant injector of which an injection direction is inclined from an axial line of the fuel injector toward the intake port.

[0040] According to the embodiment described above, it is possible to effectively inject the fuel toward the intake port.

[0041] According to one preferred embodiment, the intake valve is implemented as a poppet valve including an umbrella portion that covers the intake port and a rod-shaped stem that extends from the umbrella portion. The fuel injector is arranged so that a straight line that extends in the injection direction from the injection port crosses the umbrella portion.

[0042] According to the embodiment described above, it is possible to effectively inject the fuel toward the intake port.

ADVANTAGEOUS EFFECTS OF INVENTION

[0043] According to the present invention, it is possible to reduce the size of a straddled vehicle having an internal combustion engine including a motor for actuating a throttle valve and a fuel injector.

BRIEF DESCRIPTION OF DRAWINGS

[0044] 

FIG 1 is a left side view of a motorcycle according to an embodiment.

FIG 2 is a right side view of a portion of a vehicle frame, an internal combustion engine, an air cleaner and a fuel tank.

FIG. 3 is a cross-sectional view of the internal combustion engine and the air cleaner.

FIG. 4 is an enlarged cross-sectional view of a portion of the internal combustion engine and a portion of the air cleaner.

FIG. 5 is equivalent to FIG 3, except for the addition of auxiliary lines.

FIG. 6 is equivalent to FIG 4, except for the addition of auxiliary lines.

DESCRIPTION OF EMBODIMENTS

[0045] An embodiment of the present invention will now be described with reference to the drawings. FIG 1 is a left side view of a motorcycle 50 according to the present embodiment.

[0046] The terms front, rear, left, right, up and down, as used in the description below, refer to these directions as seen from a virtual rider seated on a seat 21 while the motorcycle 50 is standing upright on a horizontal surface with no rider, no fuel and no load thereon, unless specified otherwise. The designations F, Re, L, R, U and D, as used in the figures, refer to front, rear, left, right, up and down, respectively. Unless specified otherwise, the term "front/forward" refers not only to the direction that extends in the front direction along the vehicle center line, as the vehicle is seen from above, but also to directions that are inclined left/right from that direction by an angle that is less than or equal to 45 degrees. Similarly, the term "rear/rearward" refers not only to the direction that extends rearward along the vehicle center line, as the vehicle is seen from above, but also to directions that are inclined left/right from that direction by an angle of 45 degrees of less. The term "left/leftward" refers not only to the direction that extends leftward vertical to the vehicle center line, as the vehicle is seen from above, but also to directions that are inclined frontward/rearward from that direction by an angle of 45 degrees of less. The term "right/rightward" refers not only to the direction that extends rightward vertical to the vehicle center line, as the vehicle is seen from above, but also to directions that are inclined frontward/rearward from that direction by an angle of 45 degrees of less. The term "up/upward" refers not only to the vertically upward direction, as the vehicle is seen from sideways, but also to directions that are inclined frontward/rearward from that direction by an angle of 45 degrees of less. The term "down/downward" refers not only to the vertically downward direction, as the vehicle is seen from sideways, but also to directions that are inclined frontward/rearward from that direction by an angle of 45 degrees of less.

[0047] As shown in FIG 1, the motorcycle 50 includes a vehicle frame 22, a front wheel 23, a rear wheel 24, an internal combustion engine (hereinafter "engine") 15, an air cleaner 35 covered by an external cover 35A (see FIG 2), a fuel tank 14, and the seat 21. The seat 21 is arranged rearward of the fuel tank 14.

[0048] The vehicle frame 22 includes a head pipe 26, left and right side frames 27 extending rearward and outward in the vehicle width direction from the head pipe 26, and left and right down frames 28 extending downward from the rear end of the left and right side frames 27. A steering shaft (not shown), to which a handle 29 is secured, is supported on the head pipe 26 so that the steering shaft can pivot left and right. The steering shaft is secured to a front fork 30.

[0049] The front wheel 23 is supported on the front fork 30. The rear wheel 24 is supported on a rear end portion of a rear arm 31. The front end portion of the rear arm 31 is supported by a pivot shaft 32 so that the rear arm 31 can pivot up and down relative to the down frame 28. The front wheel 23 is a driven wheel. The rear wheel 24 is a driving wheel that is driven by the engine 15. The engine 15 and the rear wheel 24 are linked by a chain 33. The chain 33 is an example of a power transmission member. Note however that the power transmission member that transmits the power of the engine 15 to the rear wheel 24 is not limited to the chain 33, but it may be a transmission belt, a drive shaft, etc.

[0050] FIG 2 is a right side view of a portion of the vehicle frame 22, the engine 15, the air cleaner 35 and the fuel tank 14. FIG 3 is a cross-sectional view of the engine 15 and the air cleaner 35. FIG. 4 is an enlarged cross-sectional view of a portion of the engine 15 and a portion of the air cleaner 35. Note that FIG 3 and FIG 4 are cross-sectional views along a direction orthogonal to the vehicle width direction.

[0051] As shown in FIG 2, the engine 15 is supported on the vehicle frame 22. As shown in FIG 3, the engine 15 includes a crankshaft 1, a crankcase 2, a cylinder body 3, a cylinder head 5, and a cylinder head cover 36. The engine 15 includes an intake valve 7, an exhaust valve 37, an intake cam 8, an exhaust cam 38, an intake pipe 10, an exhaust pipe 40 (see FIG 1), a fuel injector 12, a fuel injector 12B, a throttle valve 11, and a motor 13 for actuating the throttle valve 11.

[0052] The crankshaft 1 extends in the vehicle width direction. The crankshaft 1 is arranged inside the crankcase 2. The crankcase 2 rotatably supports the crankshaft 1. The cylinder body 3 extends forward and upward from the crankcase 2. A cylinder 4 is formed inside the cylinder body 3. A piston 18 is arranged inside the cylinder 4. A crank pin 19 is provided on the crankshaft 1. A connecting rod 20 is linked to the piston 18 and the crank pin 19. The piston 18 is linked to the crankshaft 1 via the connecting rod 20 and the crank pin 19. Note that reference sign 67 denotes a balancer gear, and reference sign 68 denotes a clutch.

[0053] The engine 15 of the present embodiment is an engine in which the cylinder 4 is upright at a relatively steep angle relative to the horizontal line. As shown in FIG 5, the angle θ1 formed between a cylinder axial line 4c and the horizontal line PL is 45 degrees or more. Note however that there is no particular limitation on the value of the angle θ1. θ1 may be less than 45 degrees.

[0054] As shown in FIG. 4, the cylinder head 5 is connected to the cylinder body 3. The cylinder head 5 extends forward and upward from the cylinder body 3. The cylinder head cover 36 is connected to the cylinder head 5. The cylinder head cover 36 extends forward and upward from the cylinder head 5. An intake port 6 and an exhaust port 39 are formed inside the cylinder head 5 with their openings facing toward the inside of the cylinder 4. An intake passsage 9 connected to the intake port 6 and an exhaust passage 41 connected to the exhaust port 39 are formed inside the cylinder head 5. The intake valve 7 is implemented as a poppet valve including an umbrella portion 42 that closes the intake port 6 and a shaft-shaped stem 43 that extends from the umbrella portion 42. The exhaust valve 37 is also implemented as a poppet valve. The intake valve 7 and the exhaust valve 37 are supported on the cylinder head 5 so that they can move in the axial direction of the stem 43. The intake valve 7 covers the intake port 6 so that it can open/close the intake port 6, and the exhaust valve 37 covers the exhaust port 39 so that it can open/close the exhaust port 39.

[0055] The intake cam 8 and the exhaust cam 38 are rotatably supported on the cylinder head 5. The intake cam 8 rotates to thereby actuate the intake valve 7. The exhaust cam 38 rotates to thereby actuate the exhaust valve 37. The center of rotation 8c of the intake cam 8 is located rearward and upward relative to the center of rotation 38c of the exhaust cam 38.

[0056] The intake pipe 10 is connected to the cylinder head 5 and is connected to the intake passage 9. The intake pipe 10 is configured to guide the air to the intake passage 9. As shown in FIG 3, the intake pipe 10 extends upward from the cylinder head 5. Specifically, the intake pipe 10 extends upward and rearward from the cylinder head 5. The dimension in the front-rear direction of the intake pipe 10 is relatively small. Herein, the center line 10c of the intake pipe 10 is located rearward relative to the center of rotation 8c of the intake cam 8 and forward relative to a rear end 13r of the motor 13.

[0057] The intake pipe 10 includes a first intake pipe 10A and a second intake pipe 10B. The first intake pipe 10A is arranged upward of the second intake pipe 10B. The first intake pipe 10A is arranged on the upstream side relative to the second intake pipe 10B. The first intake pipe 10A is attachable to and detachable from the second intake pipe 10B. The motorcycle 50 includes an actuator 10K that actuates the first intake pipe 10A.

[0058] As the actuator 10K moves the first intake pipe 10A downward, the first intake pipe 10A is connected to the second intake pipe 10B. Then, the air is sucked in through an inlet 10Ai of the first intake pipe 10A, passes through the first intake pipe 10A and the second intake pipe 10B, and then flows into the intake passage 9. As the actuator 10K moves the first intake pipe 10A upward, the first intake pipe 10A moves apart from the second intake pipe 10B. Then, the air is sucked in through an inlet 10Bi of the second intake pipe 10B, passes through the second intake pipe 10B, and is then sucked into the intake passage 9.

[0059] As the first intake pipe 10A is connected to the second intake pipe 10B, the length of the intake pipe 10 becomes the total length of the length of the first intake pipe 10A and the length of the second intake pipe 10B. As the first intake pipe 10A is moves apart from the second intake pipe 10B, the length of the intake pipe 10 becomes equal to the length of the second intake pipe 10B. Thus, by attaching and detaching the first intake pipe 10A to and from the second intake pipe 10B, the length of the intake pipe 10 is varied. Note however that the length of the intake pipe 10 does not always need to be variable. The first intake pipe 10A and the second intake pipe 10B may be always connected to each other. The first intake pipe 10A and the second intake pipe 10B may be integral with each other. The first intake pipe 10A may be omitted.

[0060] The throttle valve 11 is arranged inside the intake pipe 10 (specifically, the second intake pipe 10B). The throttle valve 11 is actuated by the motor 13. The motor 13 is linked to the throttle valve 11 so that power is transmitted therebetween. At least a portion of the motor 13 is arranged rearward of the intake pipe 10. Herein, the entirety of the motor 13 is arranged rearward relative to the center line 10c of the intake pipe 10. The entirety of the motor 13 is arranged rearward relative to the intake pipe 10.

[0061] As shown in FIG 4, the fuel injector 12 is attached to the intake pipe 10 (specifically, the second intake pipe 10B). The fuel injector 12 is attached so as to extend upward from the intake pipe 10. Although the fuel injector 12 may be attached so as to extend in the vertically upward direction, an axial line 12c of the fuel injector 12 is herein inclined from the horizontal line PL and the vertical line VL as shown in FIG 6. The angle θ2 formed between the axial line 12c of the fuel injector 12 and the horizontal line PL is greater than the angle θ1 formed between the cylinder axial line 4c and the horizontal line PL (see FIG 5). θ2>θ1.

[0062] As shown in FIG 4, a portion of the fuel injector 12 is arranged outside the intake pipe 10, and the other portion of the fuel injector 12 is arranged inside the intake pipe 10. At least a portion of the fuel injector 12 is arranged forward of the intake pipe 10. The entirety of the fuel injector 12 is arranged forward relative to the center line 10c of the intake pipe 10 (see FIG 3). An injection port 12a of the fuel injector 12 is arranged between the throttle valve 11 and the intake port 6. The injection port 12a is arranged on the downstream side relative to the throttle valve 11 in the air flow direction.

[0063] In the present embodiment, the fuel injector 12 is a slant injector of which the fuel injection direction 12s is inclined from the axial line 12c of the fuel injector 12, as shown in FIG 6. The injection direction 12s of the fuel injector 12 is inclined from the axial line 12c of the fuel injector 12 toward the intake port 6. Note that strictly speaking, the injected fuel spreads as a jet, and the injection direction is not a single direction. The injection direction of the fuel injector 12 as used herein is the direction of the center line of the jet. In the present embodiment, the injection port 12a of the fuel injector 12 has an opening inclined from the axial line 12c of the fuel injector 12 toward the intake port 6. The straight line extending from the injection port 12a to the injection direction 12s crosses the umbrella portion 42 of the intake valve 7.

[0064] There is no particular limitation on the timing for the fuel injector 12 to inject the fuel. The fuel injector 12 may inject the fuel when the intake valve 7 is open or may inject the fuel when the intake valve 7 is closed. In the present embodiment, the fuel injector 12 injects the fuel when the intake valve 7 is closed and does not inject the fuel when the intake valve 7 is open. A portion of the fuel injected from the fuel injector 12 attaches to the umbrella portion 42 of the intake valve 7 and then evaporates to be mixed with the air.

[0065] As indicated by a phantom line in FIG 5, the fuel injector 12 and the fuel tank 14 are connected together by a fuel hose 16. In the present embodiment, since the fuel tank 14 is arranged rearward relative to the intake pipe 10 and a proximal portion of the fuel injector 12 is arranged forward relative to the intake pipe 10, the fuel hose 16 needs to extend from a position rearward of the intake pipe 10 to a position forward of the intake pipe 10. The fuel hose 16 extends forward passing through the side of the intake pipe 10. Herein, the fuel hose 16 extends forward passing through the right side of the intake pipe 10. A portion of the fuel hose 16 is arranged sideward of the intake pipe 10.

[0066] The straight line 13aL of FIG 6 is a horizontal line passing through an upper end 13a of the motor 13. The straight line 13bL is a horizontal line passing through a lower end 13b of the motor 13. At least a portion of the fuel injector 12 and at least a portion of the throttle valve 11 are arranged downward relative to the upper end 13a of the motor 13 and upward relative to the lower end 13b of the motor 13. Note that in the present specification, the position of the throttle valve 11 is assumed to mean the position when the throttle valve 11 is fully open (see FIG 3 to FIG 6), unless specified otherwise. In the present embodiment, the fuel injector 12, the throttle valve 11 and the motor 13 are arranged close to each other for the up-down direction. The overall dimension in the up-down direction of the fuel injector 12, the throttle valve 11 and the motor 13 is small. The fuel injector 12, the throttle valve 11 and the motor 13 are arranged downward relative to an upper end 36u of the cylinder head cover 36.

[0067] At least a portion of the intake cam 8 is arranged downward relative to the upper end 13a of the motor 13 and upward relative to the lower end 13b of the motor 13. In the present embodiment, the intake cam 8 is also arranged at a position close to the fuel injector 12, the throttle valve 11 and the motor 13 for the up-down direction. The overall dimension in the up-down direction of the fuel injector 12, the throttle valve 11, the motor 13 and the intake cam 8 is small. The center of rotation 8c of the intake cam 8, the injection port 12a of the fuel injector 12 and the center of rotation 11c of the throttle valve 11 are arranged downward relative to the upper end 13a of the motor 13 and upward relative to the lower end 13b of the motor 13.

[0068] In FIG 6, the phantom line denoted by reference sign 8d represents the rotation path of the intake cam 8. Reference sign 8f represents the front end of the rotation path 8d, and the straight line 8fL is a vertical line passing through the front end 8f of the rotation path 8d. The straight line 13rL is a vertical line passing through the rear end 13r of the motor 13. The fuel injector 12 and the throttle valve 11 is arranged rearward relative to the front end 8f of the rotation path 8d of the intake cam 8 and forward relative to the rear end 13r of the motor 13.

[0069] In FIG 6, the straight line 8cL is a vertical line passing through the center of rotation 8c of the intake cam 8. The straight line 13cL is a vertical line passing through a center 13c of the motor 13. Note that the center 13c of the motor 13 refers to the center of rotation of the rotor (not shown) of the motor 13. The fuel injector 12 and the throttle valve 11 are arranged rearward relative to the center of rotation 8c of the intake cam 8 and forward relative to the center 13c of the motor 13.

[0070] In FIG 6, the straight line 1cL is a vertical line passing through the center of rotation 1c of the crankshaft 1. The fuel injector 12 and the throttle valve 11 are arranged rearward relative to the center of rotation 8c of the intake cam 8 and forward relative to the center of rotation 1c of the crankshaft 1.

[0071] As shown in FIG. 3, at least a portion of the motor 13 overlaps with the side frame 27, as the vehicle is seen from the side. At least a portion of the throttle valve 11 overlaps with the side frame 27, as the vehicle is seen from the side. At least a portion of the fuel injector 12 overlaps with the side frame 27, as the vehicle is seen from the side. At least a portion of the intake cam 8 overlaps with the side frame 27, as the vehicle is seen from the side. Herein, the entirety of the fuel injector 12 overlaps with the side frame 27 and the entirety of the intake cam 8 overlaps with the side frame 27, as the vehicle is seen from the side.

[0072] As shown in FIG 6, the first line L1 denotes a straight line that passes through the center of rotation 8c of the intake cam 8 and is perpendicular to the cylinder axial line 4c, as the vehicle is seen from the side. The second line L2 denotes a straight line that passes through the center 6c of the intake port 6 and is perpendicular to the cylinder axial line 4c, as the vehicle is seen from the side. The injection port 12a of the fuel injector 12, the center 11c of the throttle valve 11 and the center 13c of the motor 13 are arranged between the first line L1 and the second line L2. Herein, the injection port 12a of the fuel injector 12, the entirety of the throttle valve 11 and the entirety of the motor 13 are arranged between the first line L1 and the second line L2, as the vehicle is seen from the side.

[0073] As shown in FIG 3, the air cleaner 35 includes an air cleaner case 17 and an element 45 arranged inside the air cleaner case 17. The air cleaner case 17 includes an inlet opening 17b through which the air flows in, and a connection port 17a to which the intake pipe 10 is connected. An upper portion of the intake pipe 10 is inserted into the air cleaner case 17 through the connection port 17a. The air flows into the air cleaner case 17 through the inlet opening 17b and is cleaned while passing through the element 45, after which the air is sucked into the intake pipe 10.

[0074] The motor 13, the throttle valve 11, the fuel injector 12 and the intake cam 8 are located downward of the air cleaner 35. The motor 13, the throttle valve 11, the fuel injector 12 and the intake cam 8 are arranged rearward relative to the front end of the air cleaner case 17 and forward relative to the rear end of the air cleaner case 17.

[0075] In FIG 5, the straight line 17uL is a horizontal line passing through an upper end 17u of the connection port 17a of the air cleaner case 17. The straight line 17dL is a horizontal line passing through a lower end 17d of the connection port 17a of the air cleaner case 17. At least a portion of the fuel injector 12 is located downward relative to the upper end 17u of the connection port 17a of the air cleaner case 17 and upward relative to the lower end 17d of the connection port 17a.

[0076] In FIG 5, the phantom line denoted by reference sign 19d represents the rotation path of the crank pin 19. That is, the crank pin 19 revolves around the center of the crankshaft 1 as the crankshaft 1 rotates, and the phantom line 19d represents the path of the portion of the crank pin 19 that is farthest away from the center of the crankshaft 1. The straight line 19fL is a vertical line passing through a front end 19f of the rotation path 19d of the crank pin 19. The straight line 19rL is a vertical line passing through a rear end 19r of the rotation path 19d of the crank pin 19. At least a portion of the connection port 17a of the air cleaner case 17, at least a portion of the throttle valve 11 and at least a portion of the motor 13 are located rearward relative to the front end 19f of the rotation path 19d of the crank pin 19 and forward relative to the rear end 19r of the rotation path 19d.

[0077] In FIG 5, the straight line L3 is a straight line that passes through the center 13c of the motor 13 and is parallel to the cylinder axial line 4c, as the vehicle is seen from the side. The straight line L3 that passes through the center 13c of the motor 13 and is parallel to the cylinder axial line 4c overlaps with the air cleaner case 17, as the vehicle is seen from the side.

[0078] The motorcycle 50 is configured as described above. Next, various effects of the motorcycle 50 according to the present embodiment will be described.

[0079] With the motorcycle 50 according to the present embodiment, as shown in FIG. 3, the cylinder body 3 and the cylinder head 5 of the engine 15 extend forward and upward from the crankcase 2, and the intake pipe 10 extends upward from the cylinder head 5. Therefore, there is no margin of space forward of a portion of the intake pipe 10 that is close to the cylinder head 5. There is only a small V-shaped space between the intake pipe 10 and the cylinder head 5, as the vehicle is seen from the side.

[0080] However, in the present embodiment, the motor 13, which is conventionally arranged forward of the intake pipe 10, is arranged rearward of the intake pipe 10. Therefore, the motor 13 is arranged at a portion of the intake pipe 10 that is close to the cylinder head 5.

[0081] In the present embodiment, the fuel injector 12, which is conventionally arranged rearward of the intake pipe 10, is arranged forward of the intake pipe 10. This realizes a compact arrangement of the fuel injector 12, wherein the fuel injector 12 and the motor 13 do not interfere with each other.

[0082] Furthermore, according to the present embodiment, at least a portion of the fuel injector 12 and at least a portion of the throttle valve 11 are arranged downward relative to the upper end 13a of the motor 13 and upward relative to the lower end 13b of the motor 13, as shown in FIG 6. The overall dimension in the up-down direction of the motor 13, the fuel injector 12 and the throttle valve 11 is small. Therefore, it is possible to reduce the size of the engine 15, and hence to reduce the size of the motorcycle 50.

[0083] According to the present embodiment, since the motor 13 is arranged at a portion of the intake pipe 10 that is close to the cylinder head 5, the throttle valve 11 is arranged at a position close to the cylinder head 5 without elongating the power transmission path between the motor 13 and the throttle valve 11. Therefore, it is possible to shorten the distance between the throttle valve 11 and the intake port 6. Thus, it is possible to reduce the size of the engine 15 and also enhance the responsiveness of the power of the engine 15 in response to changes in the opening of the throttle valve 11, and it is possible to improve the performance of the engine 15.

[0084] Furthermore, according to the present embodiment, at least a portion of the intake cam 8 is arranged downward relative to the upper end 13a of the motor 13 and upward relative to the lower end 13b. Therefore, since it is possible to suppress the overall dimension in the up-down direction of the motor 13, the fuel injector 12, the throttle valve 11 and the cylinder head 5 (specifically, a portion of the cylinder head 5 where the intake cam 8 is provided), it is possible to further reduce the size of the engine 15.

[0085] Without particular limitation thereto, according to the present embodiment, the center of rotation 8c of the intake cam 8, the injection port 12a of the fuel injector 12 and the center of rotation 11c of the throttle valve 11 are arranged downward relative to the upper end 13a of the motor 13 and upward relative to the lower end 13b of the motor 13. Thus, it is possible to further reduce the size of the engine 15.

[0086] According to the present embodiment, the fuel injector 12 and the throttle valve 11 are arranged rearward relative to the front end 8f of the rotation path of the intake cam 8 and forward relative to the rear end 13r of the motor 13. Without particular limitation thereto, the fuel injector 12 and the throttle valve 11 are arranged rearward relative to the center of rotation 8c of the intake cam 8 and forward relative to the center 13c of the motor 13. The fuel injector 12 and the throttle valve 11 are arranged rearward relative to the center of rotation 8c of the intake cam 8 and forward relative to the center of rotation 1c of the crankshaft 1. According to the present embodiment, the overall dimension in the front-rear direction of the motor 13, the throttle valve 11, the fuel injector 12 and the intake cam 8 is small. Therefore, it is possible to further reduce the size of the engine 15.

[0087] According to the present embodiment, the injection port 12a of the fuel injector 12, the center 11c of the throttle valve 11 and the center 13c of the motor 13 are arranged between the first line L1, which passes through the center of rotation 8c of the intake cam 8 and is perpendicular to the cylinder axial line 4c, and the second line L2, which passes through the center 6c of the intake port 6 and is perpendicular to the cylinder axial line 4c, as the vehicle is seen from the side. Without particular limitation thereto, the injection port 12a of the fuel injector 12, the entirety of the throttle valve 11 and the entirety of the motor 13 are arranged between the first line L1 and the second line L2, as the vehicle is seen from the side. According to the present embodiment, it is possible to suppress the overall dimension of the motor 13, the throttle valve 11, the fuel injector 12 and the intake cam 8 for the direction along the cylinder axial line 4c. Thus, it is possible to further reduce the size of the engine 15.

[0088] According to the present embodiment, the center line 10c of the intake pipe 10 is located rearward relative to the center of rotation 8c of the intake cam 8 and forward relative to the rear end 13r of the motor 13, as shown in FIG 3. According to the present embodiment, the dimension of the intake pipe 10 in the front-rear direction is small. Thus, it is possible to further reduce the size of the engine 15.

[0089] According to the present embodiment, the angle θ1 formed between the cylinder axial line 4c and the horizontal line PL is 45 degrees or more, as the vehicle is seen from the side, as shown in FIG 5. With the motorcycle 50, since the inclination of the cylinder 4 is large, there is a small space between the cylinder body 3 and the cylinder head 5 and the intake pipe 10. Therefore, the aforementioned effects, e.g., being able to arrange the motor 13 at a portion of the intake pipe 10 that is close to the cylinder head 5, are particularly pronounced.

[0090] According to the present embodiment, the angle θ2 formed between the axial line 12c of the fuel injector 12 and the horizontal line PL is greater than the angle θ1 formed between the cylinder axial line 4c and the horizontal line PL (see FIG 5), as the vehicle is seen from the side, as shown in FIG 6. The fuel injector 12 is arranged in an attitude that is more along the vertical direction. Therefore, the dimension in the front-rear direction of the fuel injector 12 is small. Thus, the fuel injector 12 is arranged in a compact arrangement in a V-shaped small space between the cylinder head 5 and the intake pipe 10.

[0091] According to the present embodiment, at least a portion of the fuel injector 12 is arranged forward of the intake pipe 10, and at least a portion of the motor 13 is arranged rearward of the intake pipe 10. Thus, the side frame 27 is arranged sideward of the intake pipe 10 without being interfered by the fuel injector 12 and the motor 13. According to the present embodiment, at least a portion of the throttle valve 11, at least a portion of the fuel injector 12 and at least a portion of the motor 13 overlap with the side frame 27, as the vehicle is seen from the side (see FIG 3), and arranged in a compact arrangement sideward of the side frame 27. The overall dimension in the up-down direction of the throttle valve 11, the fuel injector 12, the motor 13 and the side frame 27 is small. Therefore, it is possible to reduce the size of the motorcycle 50.

[0092] Now, in the present embodiment, since the fuel injector 12 is arranged forward of the intake pipe 10, the fuel hose 16 that connects the fuel tank 14, which is arranged rearward of the intake pipe 10, with the fuel injector 12 needs to be extended to a position rearward of the intake pipe 10 to a position forward of the intake pipe 10. However, according to the present embodiment, the fuel hose 16 extends from the fuel tank 14 toward the fuel injector 12 through the side of the intake pipe 10. Since the motor 13 is arranged rearward of the intake pipe 10, it is possible to easily avoid the interference between the fuel hose 16 and the motor 13.

[0093] According to the present embodiment, at least a portion of the connection port 17a of the air cleaner case 17, at least a portion of the throttle valve 11 and at least a portion of the motor 13 are located rearward relative to the front end 19f of the rotation path 19d of the crank pin 19 and forward relative to the rear end 19r, as shown in FIG 5. The overall dimension in the front-rear direction of the connection port 17a of the air cleaner case 17, the throttle valve 11 and the motor 13 is small. Therefore, it is possible to reduce the size of the motorcycle 50.

[0094] According to the present embodiment, at least a portion of the fuel injector 12 is located downward relative to the upper end 17u of the connection port 17a of the air cleaner case 17 and upward relative to the lower end 17d of the connection port 17a. The distance in the up-down direction between the connection port 17a of the air cleaner case 17 and the fuel injector 12 is short. Therefore, it is possible to reduce the size of the motorcycle 50.

[0095] According to the present embodiment, the straight line L3, which passes through the center 13c of the motor 13 and is parallel to the cylinder axial line 4c, overlaps with the air cleaner case 17, as the vehicle is seen from the side. The motor 13 is arranged close to the air cleaner case 17. Since the motor 13 and the air cleaner case 17 are arranged in a compact arrangement, it is possible to reduce the size of the motorcycle 50.

[0096] According to the present embodiment, the fuel injector 12 is a slant injector of which the injection direction 12s is inclined from the axial line 12c of the fuel injector 12 toward the intake port 6, as shown in FIG 6. The fuel injector 12 is arranged so that the straight line extending from the injection port 12a to the injection direction 12s crosses the umbrella portion 42 of the intake valve 7. Therefore, it is possible to effectively inject the fuel toward the intake port 6.

[0097] While one embodiment has been described above, the embodiment is merely illustrative, and various other embodiments are possible.

[0098] The internal combustion engine may be a multi-cylinder internal combustion engine including a plurality of cylinders 4 or may be a single-cylinder internal combustion engine including only one cylinder 4. The internal combustion engine may be a water-cooled internal combustion engine or may be an air-cooled internal combustion engine.

[0099] The side frame 27 does not always need to overlap with at least a portion of the throttle valve 11, at least a portion of the fuel injector 12 and at least a portion of the motor 13, as the vehicle is seen from the side.

[0100] The fuel injector 12 does not need to be a slant injector. The straight line extending in the injection direction 12s of the fuel injector 12 does not need to cross the umbrella portion 42 of the intake valve 7.

[0101] A straddled vehicle refers to a vehicle that is straddled by a passenger. While a motorcycle is an example of a straddled vehicle, a straddled vehicle is not limited to a motorcycle. A straddled vehicle may include an auto tricycle, an ATV (All Terrain Vehicle), and the like, as well as a motorcycle.

REFERENCE SIGNS LIST

[0102] 

1

Crankshaft

2

Crankcase

3

Cylinder body

4

Cylinder

5

Cylinder head

6

Intake port

7

Intake valve

8

Intake cam

9

Intake port

10

Intake pipe

11

Throttle valve

12

Fuel injector

12a

Injection port

13

Motor

14

Fuel tank

15

Internal combustion engine

16

Fuel hose

17

Air cleaner case

17a

Connection port

18

Piston

19

Crank pin

20

Connecting rod

22

Vehicle frame

27

Side frame

42

Umbrella portion

43

Stem

50

Motorcycle (straddled vehicle)

Claims

1. A straddled vehicle comprising an internal combustion engine (15), the internal combustion engine (15) comprising:

a crankcase (2) that rotatably supports a crankshaft (1) extending in a vehicle width direction;

a cylinder body (3) extending forward and upward from the crankcase (2);

a cylinder (4) formed inside the cylinder body (3);

a cylinder head (5) connected to the cylinder body (3);

an intake port (6) that is formed inside the cylinder head (5) and has an opening facing toward an inside of the cylinder (4);

an intake valve (7) that is supported on the cylinder head (5) and opens/closes the intake port (6);

an intake cam (8) that is rotatably supported on the cylinder head (5) and actuates the intake valve (7);

an intake passage (9) that is formed inside the cylinder head (5) and is connected to the intake port (7);

an intake pipe (10) that is connected to the cylinder head (5), extends upward from the cylinder head (5) and is connected to the intake passage (9);

a throttle valve (11) that is arranged inside the intake pipe (10);

a fuel injector (12) that has an injection port (12a) arranged between the throttle valve (11) and the intake port (6); and

a motor (13) that is linked to the throttle valve (11) and actuates the throttle valve (11), wherein:

at least a portion of the fuel injector (12) is arranged forward of the intake pipe (10);

at least a portion of the motor (13) is arranged rearward of the intake pipe (10); and

at least a portion of the fuel injector (12) and at least a portion of the throttle valve (11) are arranged downward relative to an upper end (13a) of the motor (13) and upward relative to a lower end (13b) of the motor (13).

2. The straddled vehicle according to claim 1, wherein at least a portion of the intake cam (8) is arranged downward relative to the upper end (13a) of the motor (13) and upward relative to the lower end (13b) of the motor (13).

3. The straddled vehicle according to claim 1 or 2, wherein a center of rotation (8c) of the intake cam (8), the injection port (12a) of the fuel injector (12) and a center of rotation (11c) of the throttle valve (11) are arranged downward relative to the upper end (13a) of the motor (13) and upward relative to the lower end (13b) of the motor (13).

4. The straddled vehicle according to any one of claims 1 to 3,
wherein the fuel injector (12) and the throttle valve (11) are arranged rearward relative to a front end (8f) of a rotation path (8d) of the intake cam (8) and forward relative to a rear end (13r) of the motor (13); and/or
wherein the fuel injector (12) and the throttle valve (11) are arranged rearward relative to the center of rotation (8c) of the intake cam (8) and forward relative to a center (13c) of the motor (13); and/or
wherein the fuel injector (12) and the throttle valve (11) are arranged rearward relative to the center of rotation (8c) of the intake cam (8) and forward relative to a center of rotation (1c) of the crankshaft (1).

5. The straddled vehicle according to any one of claims 1 to 4, wherein where a first line (L1) is defined as a straight line that passes through a center of rotation (8c) of the intake cam (8) and is perpendicular to an axial line (4c) of the cylinder (4) and a second line (L2) as a straight line that passes through a center (6c) of the intake port (6) and is perpendicular to the axial line (4c) of the cylinder (4), the injection port (12a) of the fuel injector (12), a center (11c) of the throttle valve (11) and a center (13c) of the motor (13) are arranged between the first line (L1) and the second line (L2), as the vehicle is seen from the side.

6. The straddled vehicle according to any one of claims 1 to 5, wherein the injection port (12a) of the fuel injector (12), an entirety of the throttle valve (11) and an entirety of the motor (13) are arranged between the first line (L1) and the second line (L2), as the vehicle is seen from the side.

7. The straddled vehicle according to any one of claims 1 to 6, wherein a center line (10c) of the intake pipe (10) is located rearward relative to a center of rotation (8c) of the intake cam (8) and forward relative to a rear end (13r) of the motor (13).

8. The straddled vehicle according to any one of claims 1 to 7,
wherein an angle (θ1) formed between an axial line (4c) of the cylinder (4) and a horizontal line (PL) is 45 degrees or more, as the vehicle is seen from the side; and/or
wherein an angle (θ2) formed between an axial line (12c) of the fuel injector (12) and a horizontal line (PL) is greater than an angle (θ1) formed between an axial line (4c) of the cylinder (4) and the horizontal line (PL), as the vehicle is seen from the side.

9. The straddled vehicle according to any one of claims 1 to 8, comprising:

a vehicle frame (22) that supports the internal combustion engine (15),

wherein the vehicle frame (22) includes a side frame (27) that overlaps with at least a portion of the throttle valve (11), at least a portion of the fuel injector (12) and at least a portion of the motor (13), as the vehicle is seen from the side.

10. The straddled vehicle according to any one of claims 1 to 9, comprising:

a fuel tank (14) arranged rearward relative to the intake pipe (10); and

a fuel hose (16) connected to the fuel tank (14) and the fuel injector (12),

wherein a portion of the fuel hose (16) is arranged sideward of the intake pipe (10).

11. The straddled vehicle according to any one of claims 1 to 10, comprising an air cleaner case (17) including a connection port (17a) to which the intake pipe (10) is connected.

12. The straddled vehicle according to claim 11, wherein:

the internal combustion engine (15) includes:

a piston (18) arranged in the cylinder (4);

a crank pin (19) provided on the crankshaft (1); and

a connecting rod (20) linked to the piston (18) and the crank pin (19),

wherein at least a portion of the connection port (17a) of the air cleaner case (17), at least a portion of the throttle valve (11) and at least a portion of the motor (13) are located rearward relative to a front end (19f) of a rotation path (19d) of the crank pin (19) and forward relative to a rear end (19r) of the rotation path (19d) of the crank pin (19).

13. The straddled vehicle according to claim 11 or 12,
wherein at least a portion of the fuel injector (12) is located downward relative to an upper end (17u) of the connection port (17a) of the air cleaner case (17) and upward relative to a lower end (17d) of the connection port (17a); and/or
wherein a straight line (L3) that passes through a center (13c) of the motor (13) and is parallel to an axial line (4c) of the cylinder (4) overlaps with the air cleaner case (17), as the vehicle is seen from the side.

14. The straddled vehicle according to any one of claims 1 to 13, wherein the fuel injector (12) is a slant injector of which an injection direction (12s) is inclined from an axial line (12c) of the fuel injector (12) toward the intake port (6).

15. The straddled vehicle according to claim 14, wherein:

the intake valve (7) is implemented as a poppet valve including an umbrella portion (42) that covers the intake port (6) and a rod-shaped stem (43) that extends from the umbrella portion (42); and

the fuel injector (12) is arranged so that a straight line that extends in the injection direction (12s) from the injection port (12a) crosses the umbrella portion (42).

Drawing