Patent Description:
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. <NUM> of <CIT> describes such an internal combustion engine. With the internal combustion engine described in <CIT>, 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. A straddled vehicle according to the preamble of claim <NUM> is disclosed in <CIT>.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

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.

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.

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.

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.

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.

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.

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.

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

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.

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.

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.

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.

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.

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.

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.

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

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.

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.

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

An embodiment of the present invention will now be described with reference to the drawings. <FIG> is a left side view of a motorcycle <NUM> according to the present embodiment.

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 <NUM> while the motorcycle <NUM> 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 <NUM> 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 <NUM> 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 <NUM> 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 <NUM> 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 <NUM> 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 <NUM> degrees of less.

As shown in <FIG>, the motorcycle <NUM> includes a vehicle frame <NUM>, a front wheel <NUM>, a rear wheel <NUM>, an internal combustion engine (hereinafter "engine") <NUM>, an air cleaner <NUM> covered by an external cover 35A (see <FIG>), a fuel tank <NUM>, and the seat <NUM>. The seat <NUM> is arranged rearward of the fuel tank <NUM>.

The vehicle frame <NUM> includes a head pipe <NUM>, left and right side frames <NUM> extending rearward and outward in the vehicle width direction from the head pipe <NUM>, and left and right down frames <NUM> extending downward from the rear end of the left and right side frames <NUM>. A steering shaft (not shown), to which a handle <NUM> is secured, is supported on the head pipe <NUM> so that the steering shaft can pivot left and right. The steering shaft is secured to a front fork <NUM>.

The front wheel <NUM> is supported on the front fork <NUM>. The rear wheel <NUM> is supported on a rear end portion of a rear arm <NUM>. The front end portion of the rear arm <NUM> is supported by a pivot shaft <NUM> so that the rear arm <NUM> can pivot up and down relative to the down frame <NUM>. The front wheel <NUM> is a driven wheel. The rear wheel <NUM> is a driving wheel that is driven by the engine <NUM>. The engine <NUM> and the rear wheel <NUM> are linked by a chain <NUM>. The chain <NUM> is an example of a power transmission member. Note however that the power transmission member that transmits the power of the engine <NUM> to the rear wheel <NUM> is not limited to the chain <NUM>, but it may be a transmission belt, a drive shaft, etc..

<FIG> is a right side view of a portion of the vehicle frame <NUM>, the engine <NUM>, the air cleaner <NUM> and the fuel tank <NUM>. <FIG> is a cross-sectional view of the engine <NUM> and the air cleaner <NUM>. <FIG> is an enlarged cross-sectional view of a portion of the engine <NUM> and a portion of the air cleaner <NUM>. Note that <FIG> and <FIG> are cross-sectional views along a direction orthogonal to the vehicle width direction.

As shown in <FIG>, the engine <NUM> is supported on the vehicle frame <NUM>. As shown in <FIG>, the engine <NUM> includes a crankshaft <NUM>, a crankcase <NUM>, a cylinder body <NUM>, a cylinder head <NUM>, and a cylinder head cover <NUM>. The engine <NUM> includes an intake valve <NUM>, an exhaust valve <NUM>, an intake cam <NUM>, an exhaust cam <NUM>, an intake pipe <NUM>, an exhaust pipe <NUM> (see <FIG>), a fuel injector <NUM>, a fuel injector 12B, a throttle valve <NUM>, and a motor <NUM> for actuating the throttle valve <NUM>.

The crankshaft <NUM> extends in the vehicle width direction. The crankshaft <NUM> is arranged inside the crankcase <NUM>. The crankcase <NUM> rotatably supports the crankshaft <NUM>. The cylinder body <NUM> extends forward and upward from the crankcase <NUM>. A cylinder <NUM> is formed inside the cylinder body <NUM>. A piston <NUM> is arranged inside the cylinder <NUM>. A crank pin <NUM> is provided on the crankshaft <NUM>. A connecting rod <NUM> is linked to the piston <NUM> and the crank pin <NUM>. The piston <NUM> is linked to the crankshaft <NUM> via the connecting rod <NUM> and the crank pin <NUM>. Note that reference sign <NUM> denotes a balancer gear, and reference sign <NUM> denotes a clutch.

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

As shown in <FIG>, the cylinder head <NUM> is connected to the cylinder body <NUM>. The cylinder head <NUM> extends forward and upward from the cylinder body <NUM>. The cylinder head cover <NUM> is connected to the cylinder head <NUM>. The cylinder head cover <NUM> extends forward and upward from the cylinder head <NUM>. An intake port <NUM> and an exhaust port <NUM> are formed inside the cylinder head <NUM> with their openings facing toward the inside of the cylinder <NUM>. An intake passsage <NUM> connected to the intake port <NUM> and an exhaust passage <NUM> connected to the exhaust port <NUM> are formed inside the cylinder head <NUM>. The intake valve <NUM> is implemented as a poppet valve including an umbrella portion <NUM> that closes the intake port <NUM> and a shaft-shaped stem <NUM> that extends from the umbrella portion <NUM>. The exhaust valve <NUM> is also implemented as a poppet valve. The intake valve <NUM> and the exhaust valve <NUM> are supported on the cylinder head <NUM> so that they can move in the axial direction of the stem <NUM>. The intake valve <NUM> covers the intake port <NUM> so that it can open/close the intake port <NUM>, and the exhaust valve <NUM> covers the exhaust port <NUM> so that it can open/close the exhaust port <NUM>.

The intake cam <NUM> and the exhaust cam <NUM> are rotatably supported on the cylinder head <NUM>. The intake cam <NUM> rotates to thereby actuate the intake valve <NUM>. The exhaust cam <NUM> rotates to thereby actuate the exhaust valve <NUM>. The center of rotation 8c of the intake cam <NUM> is located rearward and upward relative to the center of rotation 38c of the exhaust cam <NUM>.

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

The intake pipe <NUM> 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 <NUM> includes an actuator <NUM> that actuates the first intake pipe 10A.

As the actuator <NUM> 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 <NUM>. As the actuator <NUM> 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 <NUM>.

As the first intake pipe 10A is connected to the second intake pipe 10B, the length of the intake pipe <NUM> 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 <NUM> 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 <NUM> is varied. Note however that the length of the intake pipe <NUM> 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.

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

As shown in <FIG>, the fuel injector <NUM> is attached to the intake pipe <NUM> (specifically, the second intake pipe 10B). The fuel injector <NUM> is attached so as to extend upward from the intake pipe <NUM>. Although the fuel injector <NUM> may be attached so as to extend in the vertically upward direction, an axial line 12c of the fuel injector <NUM> is herein inclined from the horizontal line PL and the vertical line VL as shown in <FIG>. The angle θ2 formed between the axial line 12c of the fuel injector <NUM> 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>).

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

In the present embodiment, the fuel injector <NUM> is a slant injector of which the fuel injection direction <NUM> is inclined from the axial line 12c of the fuel injector <NUM>, as shown in <FIG>. The injection direction <NUM> of the fuel injector <NUM> is inclined from the axial line 12c of the fuel injector <NUM> toward the intake port <NUM>. 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 <NUM> 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 <NUM> has an opening inclined from the axial line 12c of the fuel injector <NUM> toward the intake port <NUM>. The straight line extending from the injection port 12a to the injection direction <NUM> crosses the umbrella portion <NUM> of the intake valve <NUM>.

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

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

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

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

In <FIG>, the phantom line denoted by reference sign 8d represents the rotation path of the intake cam <NUM>. 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 <NUM>. The fuel injector <NUM> and the throttle valve <NUM> is arranged rearward relative to the front end 8f of the rotation path 8d of the intake cam <NUM> and forward relative to the rear end 13r of the motor <NUM>.

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

In <FIG>, the straight line 1cL is a vertical line passing through the center of rotation 1c of the crankshaft <NUM>. The fuel injector <NUM> and the throttle valve <NUM> are arranged rearward relative to the center of rotation 8c of the intake cam <NUM> and forward relative to the center of rotation 1c of the crankshaft <NUM>.

As shown in <FIG>, at least a portion of the motor <NUM> overlaps with the side frame <NUM>, as the vehicle is seen from the side. At least a portion of the throttle valve <NUM> overlaps with the side frame <NUM>, as the vehicle is seen from the side. At least a portion of the fuel injector <NUM> overlaps with the side frame <NUM>, as the vehicle is seen from the side. At least a portion of the intake cam <NUM> overlaps with the side frame <NUM>, as the vehicle is seen from the side. Herein, the entirety of the fuel injector <NUM> overlaps with the side frame <NUM> and the entirety of the intake cam <NUM> overlaps with the side frame <NUM>, as the vehicle is seen from the side.

As shown in <FIG>, the first line L1 denotes a straight line that passes through the center of rotation 8c of the intake cam <NUM> 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 <NUM> 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 <NUM>, the center 11c of the throttle valve <NUM> and the center 13c of the motor <NUM> are arranged between the first line L1 and the second line L2. Herein, the injection port 12a of the fuel injector <NUM>, the entirety of the throttle valve <NUM> and the entirety of the motor <NUM> are arranged between the first line L1 and the second line L2, as the vehicle is seen from the side.

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

The motor <NUM>, the throttle valve <NUM>, the fuel injector <NUM> and the intake cam <NUM> are located downward of the air cleaner <NUM>. The motor <NUM>, the throttle valve <NUM>, the fuel injector <NUM> and the intake cam <NUM> are arranged rearward relative to the front end of the air cleaner case <NUM> and forward relative to the rear end of the air cleaner case <NUM>.

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

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

In <FIG>, the straight line L3 is a straight line that passes through the center 13c of the motor <NUM> 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 <NUM> and is parallel to the cylinder axial line 4c overlaps with the air cleaner case <NUM>, as the vehicle is seen from the side.

The motorcycle <NUM> is configured as described above. Next, various effects of the motorcycle <NUM> according to the present embodiment will be described.

With the motorcycle <NUM> according to the present embodiment, as shown in <FIG>, the cylinder body <NUM> and the cylinder head <NUM> of the engine <NUM> extend forward and upward from the crankcase <NUM>, and the intake pipe <NUM> extends upward from the cylinder head <NUM>. Therefore, there is no margin of space forward of a portion of the intake pipe <NUM> that is close to the cylinder head <NUM>. There is only a small V-shaped space between the intake pipe <NUM> and the cylinder head <NUM>, as the vehicle is seen from the side.

However, in the present embodiment, the motor <NUM>, which is conventionally arranged forward of the intake pipe <NUM>, is arranged rearward of the intake pipe <NUM>. Therefore, the motor <NUM> is arranged at a portion of the intake pipe <NUM> that is close to the cylinder head <NUM>.

In the present embodiment, the fuel injector <NUM>, which is conventionally arranged rearward of the intake pipe <NUM>, is arranged forward of the intake pipe <NUM>. This realizes a compact arrangement of the fuel injector <NUM>, wherein the fuel injector <NUM> and the motor <NUM> do not interfere with each other.

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

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

Furthermore, according to the present embodiment, at least a portion of the intake cam <NUM> is arranged downward relative to the upper end 13a of the motor <NUM> 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 <NUM>, the fuel injector <NUM>, the throttle valve <NUM> and the cylinder head <NUM> (specifically, a portion of the cylinder head <NUM> where the intake cam <NUM> is provided), it is possible to further reduce the size of the engine <NUM>.

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

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

According to the present embodiment, the injection port 12a of the fuel injector <NUM>, the center 11c of the throttle valve <NUM> and the center 13c of the motor <NUM> are arranged between the first line L1, which passes through the center of rotation 8c of the intake cam <NUM> and is perpendicular to the cylinder axial line 4c, and the second line L2, which passes through the center 6c of the intake port <NUM> 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 <NUM>, the entirety of the throttle valve <NUM> and the entirety of the motor <NUM> 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 <NUM>, the throttle valve <NUM>, the fuel injector <NUM> and the intake cam <NUM> for the direction along the cylinder axial line 4c. Thus, it is possible to further reduce the size of the engine <NUM>.

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

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

According to the present embodiment, the angle θ2 formed between the axial line 12c of the fuel injector <NUM> 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>), as the vehicle is seen from the side, as shown in <FIG>. The fuel injector <NUM> is arranged in an attitude that is more along the vertical direction. Therefore, the dimension in the front-rear direction of the fuel injector <NUM> is small. Thus, the fuel injector <NUM> is arranged in a compact arrangement in a V-shaped small space between the cylinder head <NUM> and the intake pipe <NUM>.

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

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

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

According to the present embodiment, at least a portion of the fuel injector <NUM> is located downward relative to the upper end 17u of the connection port 17a of the air cleaner case <NUM> 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 <NUM> and the fuel injector <NUM> is short. Therefore, it is possible to reduce the size of the motorcycle <NUM>.

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

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

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

The internal combustion engine may be a multi-cylinder internal combustion engine including a plurality of cylinders <NUM> or may be a single-cylinder internal combustion engine including only one cylinder <NUM>. The internal combustion engine may be a water-cooled internal combustion engine or may be an air-cooled internal combustion engine.

The side frame <NUM> does not always need to overlap with at least a portion of the throttle valve <NUM>, at least a portion of the fuel injector <NUM> and at least a portion of the motor <NUM>, as the vehicle is seen from the side.

The fuel injector <NUM> does not need to be a slant injector. The straight line extending in the injection direction <NUM> of the fuel injector <NUM> does not need to cross the umbrella portion <NUM> of the intake valve <NUM>.

Claim 1:
A straddled vehicle comprising an internal combustion engine (<NUM>), the internal combustion engine (<NUM>) comprising:
a crankcase (<NUM>) that rotatably supports a crankshaft (<NUM>) extending in a vehicle width direction;
a cylinder body (<NUM>) extending forward and upward from the crankcase (<NUM>);
a cylinder (<NUM>) formed inside the cylinder body (<NUM>);
a cylinder head (<NUM>) connected to the cylinder body (<NUM>);
an intake port (<NUM>) that is formed inside the cylinder head (<NUM>) and has an opening facing toward an inside of the cylinder (<NUM>);
an intake valve (<NUM>) that is supported on the cylinder head (<NUM>) and opens/closes the intake port (<NUM>);
an intake cam (<NUM>) that is rotatably supported on the cylinder head (<NUM>) and actuates the intake valve (<NUM>);
an intake passage (<NUM>) that is formed inside the cylinder head (<NUM>) and is connected to the intake port (<NUM>);
an intake pipe (<NUM>) that is connected to the cylinder head (<NUM>), extends upward from the cylinder head (<NUM>) and is connected to the intake passage (<NUM>);
a throttle valve (<NUM>) that is arranged inside the intake pipe (<NUM>);
a fuel injector (<NUM>) that has an injection port (12a) arranged between the throttle valve (<NUM>) and the intake port (<NUM>); and
a motor (<NUM>) that is linked to the throttle valve (<NUM>) and actuates the throttle valve (<NUM>), wherein:
at least a portion of the fuel injector (<NUM>) is arranged forward of the intake pipe (<NUM>);
at least a portion of the motor (<NUM>) is arranged rearward of the intake pipe (<NUM>);
at least a portion of the fuel injector (<NUM>) is arranged downward relative to an upper end (13a) of the motor (<NUM>) and upward relative to a lower end (13b) of the motor (<NUM>); and
at least a portion of the throttle valve (<NUM>) is arranged upward relative to the lower end (13b) of the motor (<NUM>),
characterized in that
at least the portion of the throttle valve (<NUM>) is arranged downward relative to the upper end (13a) of the motor (<NUM>).