CN110318923A - Air intake structure for the internal combustion engine used on saddle vehicle - Google Patents

Abstract

An air intake structure for an internal combustion engine (4) used on a saddle vehicle, the air intake structure includes upper surfaces, lower surfaces, left surfaces, and right surfaces of an air intake pipe (7), respectively ribs, lower ribs, left ribs, and right ribs (71, 72, 73, 74), wherein the injector (81) is arranged on one of the left rib (73) and the right rib (74) and the upper rib (71 )between. The upper rib, lower rib, left rib, and right rib of the intake pipe increase the rigidity and mechanical strength of the intake pipe against the vibration generated by the vehicle and in the intake pipe, thereby increasing the vibration control ability of the intake pipe, and even The upper rib (71) is provided on the intake pipe, and the injector can also be positioned without physically interfering with the rib.

Description

Air intake structure for an internal combustion engine used on a saddle vehicle

technical field

The present invention relates to an intake structure for an internal combustion engine used on a saddle-type vehicle, the intake structure including an intake pipe having a high vibration control capability and being less harmful to the installation of a fuel injection device.

Background technique

Some internal combustion engines used on motorcycles, such as light motorcycles (LMCs), have cylinder axes that are slightly inclined forward from vertical. This internal combustion engine includes an intake pipe extending between a carburetor and a cylinder head and having a pair of upper and lower reinforcing ribs extending in a longitudinal direction of the intake pipe and Protrude integrally from respective left and right surfaces of the intake duct. The intake pipe also includes a pair of streamlined ribs extending longitudinally of the intake pipe on respective upper and lower surfaces of the intake pipe. This type of internal combustion engine is disclosed, for example, in Patent Document 1 shown below.

Unlike the fuel supply process of supplying the air-fuel mixture into the combustion chamber using a carburetor, the process of supplying the air-fuel mixture into the combustion chamber with a fuel injection device requires disposing the injector in the intake pipe. If the latter process is employed in the internal combustion engine disclosed in Patent Document 1, the injector provided in the intake pipe tends to physically interfere with the ribs on the intake pipe.

Therefore, when ribs are provided on the intake pipe, a structure is required in which the injector and the injector mounting base are arranged so as not to physically interfere with the ribs on the intake pipe.

A scooter-type motorcycle is known in the art which comprises a pivotable power unit whose cylinder axis is oriented in the longitudinal direction of the motorcycle. The swingable power unit includes an intake pipe extending from a joint between itself and the cylinder head and bent in the rearward direction of the motorcycle, and a throttle body provided upstream of the intake pipe. Since the intake pipe is vibrated when the swingable power unit is swung, the intake pipe has been required to include a structure that increases the vibration control capability of the intake pipe.

【Existing Technical Documents】

【Patent Document】

Patent Document 1: JP 2010-190083 A (Figure 2, Figure 3, Figure 7, Figure 8)

Contents of the invention

【Basic problem to be solved by the present invention】

The present invention has been made in view of the prior art described above. The object of the present invention is to provide an intake structure for an internal combustion engine used on a saddle-type vehicle, which increases the vibration control capability of the intake pipe; From the standpoint of interference, this intake structure does not adversely affect the mounting of injectors and the like of the fuel injection device.

【Means to solve the problem】

In order to achieve the above object, the present invention provides an intake structure for an internal combustion engine used on a saddle vehicle, the intake structure has an upper surface, a lower surface, a left surface, a right An upper rib, a lower rib, a left rib, and a right rib on the surface, wherein the injector is disposed between one of the left rib and the right rib and the upper rib.

With the above arrangement, the upper rib, lower rib, left rib and right rib of the intake pipe increase the rigidity and mechanical strength of the intake pipe against the vibration generated by the vehicle and in the intake pipe, thereby increasing the vibration control of the intake pipe capability, and even if the upper rib is provided on the intake pipe, the injector can be placed without physically interfering with the rib.

In the above arrangement, the internal combustion engine may be included in a swingable power unit mounted on the vehicle body frame so as to swing together with the rear wheels, and the intake pipe may be bent and routed from the intake pipe The junction between the cylinder head and the cylinder head extends toward the rear of the vehicle.

With this arrangement, in a swingable power unit in which the intake pipe bends and extends rearward from the joint between the intake pipe and the cylinder head even if the distance between the cylinder head and the throttle body is greater than a predetermined value, The upper rib, lower rib, left rib and right rib of the intake pipe also effectively increase the rigidity and mechanical strength of the intake pipe against the vibration generated by the vehicle and in the intake pipe, thereby increasing the vibration control ability of the intake pipe , and even if the upper rib is provided on the intake pipe, the injector can be placed on the intake pipe without physically interfering with the rib.

In the above arrangement, an injector-side mounting hole may be provided between the other of the left rib and the right rib and the upper rib, and the injector and the injector-side mounting hole may be respectively provided on the left and right sides of the upper rib.

With this arrangement, the rib for dealing with the vibration of the vehicle can be mounted on the intake pipe without physically interfering with the injector and the injection-side mounting hole.

In the above arrangement, the throttle body may be provided upstream of the intake pipe, and at least the lower rib, the left rib, and the right rib may have a direction toward the downstream side along the direction in which air flows through the intake pipe. Progressively larger corresponding rib heights.

With the above arrangement, even if the throttle body is connected to the upstream end of the intake pipe, the intake pipe is stably supported on the internal combustion engine.

In the above arrangement, the intake pipe may have a downstream portion connected to the cylinder head and having a connection area larger than a connection area of an upstream portion of the intake pipe connected to the throttle body.

With this arrangement, since the connection area of the intake pipe to the downstream portion of the cylinder head is larger than the connection area of the intake pipe to the upstream portion of the throttle body, even if the throttle body is connected to the upstream portion of the intake pipe, The air pipe is also stably supported on the swingable power unit.

In the above arrangement, the upper rib and the lower rib may have respective rib heights such that the greater the curvature of the intake duct, the greater the rib height, except for a peripheral area around the insertion hole, wherein, The injector is inserted into the insertion hole.

With this arrangement, the swingable power unit in which the intake pipe is curved can give the intake pipe a higher vibration control capability by increasing the rib height according to the curvature of the intake pipe.

[Effects of the present invention]

With the intake structure for an internal combustion engine used on a saddle vehicle according to the present invention, the upper ribs, lower ribs, left ribs and right ribs of the intake duct increase the resistance of the intake duct to vibrations generated by the vehicle and in the intake duct The rigidity and mechanical strength of the generated vibrations, thereby increasing the vibration control capability of the intake pipe, and even if the upper rib is provided on the intake pipe, the injector can be positioned without physically interfering with the rib.

Description of drawings

1 is a right side view of a motorcycle including an intake structure for an internal combustion engine used on a saddle vehicle according to an embodiment of the present invention;

Figure 2 is a side sectional view of the internal combustion engine in the front of the power unit shown in Figure 1, taken generally along the cylinder axis, wherein the internal combustion engine is shown in the same orientation as in Figure 1;

Figure 3 is a plan view of the internal combustion engine in the front of the power unit;

Figure 4 is a perspective view of the internal combustion engine in the front of the power unit seen from behind the internal combustion engine in a position slightly tilted to the right;

Fig. 5 is a sectional view of the cylinder head and the cylinder head side flange of the intake pipe seen along the line V-V in Fig. 3, including the axis of the injector side mounting hole;

Figure 6 is a vertical cross-sectional view of the intake duct shown in Figure 2, wherein the intake duct is shown in the same orientation as in Figure 2;

Fig. 7 is a plan view of the intake pipe mounted on the motorcycle seen along the line VII-VII of Fig. 6; and

Fig. 8 is a bottom view of the intake pipe mounted on the motorcycle seen along line VIII-VIII of Fig. 6 .

Detailed ways

An intake structure for an internal combustion engine used on a saddle vehicle according to an embodiment of the present invention will be described below together with the drawings.

In this specification and claims, expressions of directions such as forward, rearward, leftward, rightward, upward, and downward, and other directions are consistent with directions about a vehicle in which the air intake structure according to the present embodiment is included. The saddle-type vehicle in this embodiment refers specifically to a scooter-type motorcycle (hereinafter simply referred to as "motorcycle").

In the drawings, reference numeral FR denotes a forward direction of the vehicle, LH denotes a leftward direction of the vehicle, RH denotes a rightward direction of the vehicle, and UP denotes an upward direction of the vehicle.

1 to 8 relate to an embodiment of the present invention. FIG. 1 is a right side view of a motorcycle 1 including an intake structure for an internal combustion engine used on a saddle-type vehicle according to the present embodiment.

The motorcycle 1 incorporating the present embodiment includes a front vehicle body portion 1A and a rear vehicle body portion 1B interconnected by a floor portion 1C. The motorcycle 1 has a vehicle body frame 2 serving as a vehicle body skeleton, which generally includes a down frame 21 and a pair of left and right main frames 22 .

A down frame 21 extends downward from the head pipe 20 of the front vehicle body portion 1A. The left and right main frames 22 include respective lower frames 22a extending substantially horizontally rearward from the lower ends of the down frames 21 and connected to the lower ends of the down frames. The left and right main frames 22 also include a pair of left and right inclined portions 22b extending obliquely rearward and upward from the rear end of the lower frame 22a. An upper portion of the inclined portion 22b is bent and extends rearward into a pair of left and right horizontal portions 22c extending substantially horizontally.

A storage box, not shown, is supported on the inclined portion 22b and the horizontal portion 22c of the main frame 22, and is covered by the rider's seat 11 provided thereon.

In the front vehicle body portion 1A, the handlebar 12 is pivotally supported by and disposed above the head pipe 20 . The front fork 13 extends downward from the head pipe 20 . A front wheel 14 is rotatably supported on the lower end of the front fork 13 .

The power unit support bracket 23 protrudes rearward from the inclined portion 22 b of the main frame 22 . A swingable power unit (hereinafter simply referred to as “power unit”) 3 and a rear wheel 15 operatively coupled to the power unit 3 are vertically swingably connected to and supported on a power unit support bracket 23 through a link 24 together. superior.

Motorcycle 1 includes an upper link support structure for power unit 3 .

In the front vehicle body portion 1A, the head pipe 20 and the down frame 21 are covered with a front cover 10 a and a leg shield 10 b located in front and rear of the head pipe 20 and the down frame 21 , respectively.

The floor portion 1C is provided by the lower frame 22a of the main frame 22 . The lower frame 22a has an upper surface covered with the floor cover 10c, left and right surfaces covered with respective longitudinal floor side covers 10d, and a lower surface covered with the bottom cover 10e.

In the rear vehicle body portion 1B, the fuel tank 16 is mounted on a horizontal portion 22 c of the main frame 22 below the rear portion of the rider's seat 11 . The inclined portion 22b and the horizontal portion 22c of the main frame 22 have left and right portions and a rear portion covered with the body cover 10f. The front fender 10g is provided above the front wheel 14 .

Covers 10a to 10f are made of a suitable material. The bottom cover 10e should preferably but not necessarily be made of a resin material.

The power unit 3 includes an internal combustion engine 4 and a power transmission assembly 5 extending rearward from the internal combustion engine 4 and including a belt-type continuously variable transmission 51 . The rear wheels 15 are mounted on a rear shaft 52 a which is an output shaft of a reducer gear mechanism 52 provided in the rear portion of the power transmission assembly 5 .

A rear shock absorber, not shown, is interposed between the rear portion of the power transmission assembly 5 and the horizontal portion 22c (ie, the rear portion of the main frame 22).

The internal combustion engine 4 includes a crankshaft 41 that extends laterally (ie, in the left-to-right direction of the motorcycle 1 ) and is rotatably supported by the power unit case 30 . The internal combustion engine 4 has a cylinder block 42 , a cylinder head 43 and a cylinder head cover 44 which are sequentially stacked and fastened together. The cylinder block 42 has a cylinder axis C which is inclined forward to such an extent that it is placed almost horizontally.

The power unit case 30 has a structure that can be divided into left and right case members. The left housing member integrally extends rearward as part of the power transmission assembly 5 .

As shown in FIG. 2, in the upper portion of the power unit 3, the intake pipe 7 is connected to an inlet of an intake port 45 defined in the upper portion of the cylinder head 43, which is inclined forward at a large angle. The intake pipe 7 is bent and extends rearward from a joint point 7 a where it is joined to the cylinder head 43 .

The exhaust pipe 6 is connected to an outlet of an exhaust port 46 defined in a lower portion of the cylinder head 43 . The exhaust pipe 6 is connected to a catalytic converter 60 ( FIG. 1 ) having a substantially tubular shape. The catalytic converter 60 houses a catalyst 61 such as a three-way catalyst or the like, for example, for purifying exhaust gas discharged from the internal combustion engine 4 .

The exhaust pipe 6 includes a front exhaust pipe 6A ( FIG. 1 ) and a rear exhaust pipe 6B. The front exhaust pipe 6A extends downward from the outlet of the exhaust port 46 and is connected to a catalytic converter 60 whose central axis is oriented in the lateral direction of the motorcycle 1 . The rear exhaust pipe 6B connected to the catalytic converter 60 is bent rearward, extends rearward along the right side of the motorcycle 1 , and is connected to a muffler 62 provided on the right side of the rear wheel 15 .

An air cleaner 91 is mounted on the upper portion of the power transmission assembly 5 . The intake pipe 7 is bent rearward from the entrance of the intake port 45 defined in the upper portion of the cylinder head 43 and is connected to the throttle body 9 . An air cleaner 91 is provided upstream of the throttle body 9 and connected to the throttle body 9 through a connection pipe 90 .

FIG. 2 is a side sectional view of the internal combustion engine 4 in the front of the power unit 3 shown in FIG. 1 , taken approximately along the cylinder axis C. As shown in FIG.

In FIG. 2 , the vertical surfaces of the cylinder block 42 , the cylinder head 43 and the left half of the head cover 44 of the internal combustion engine 4 are shown in vertical section. The power unit case 30 has a right half case (not shown) and a left half case 30L, and a mating surface of the left half case 30L mating with a mating surface of the right half case is shown in FIG. Facing the observer in Figure 2.

The power unit case 30 is constituted by a right half case (not shown) and a left half case 30L which are combined with each other. The right half case serves as the right half of the crankcase 30a. The left half case 30L has a front portion serving as the left half of the crankcase 30a and extending rearward as part of the power transmission assembly 5 accommodating therein a power transmission device comprising Between the crankshaft 41 and the rear axle 52a on which the rear wheels 15 are mounted, a belt-type continuously variable transmission 51, a reducer gear mechanism 52, and the like.

Rotational power from a crankshaft 41 rotatably supported on a crankcase 30 a of the internal combustion engine 4 is transmitted to the rear wheels 15 through a belt type continuously variable transmission 51 and a reducer gear mechanism 52 in the power transmission assembly 5 .

The piston 31 is reciprocally disposed in a cylinder bore 42 a defined in the cylinder block 42 . Piston 31 is coupled via connecting rod 32 to crank pin 41a on crankshaft 41 in crankcase 30a.

The combustion chamber 49 is defined between the top surface (top surface) of the piston 31 slidably fitted in the cylinder bore 42a defined in the cylinder block 42 and the combustion chamber upper surface (top surface) of the cylinder head 43 facing the top surface of the piston 31 ( Between combustion chamber ceiling surface) 43a.

According to the present embodiment, the internal combustion engine 4 includes the SOHC two-valve system including the valve operating mechanism 35 provided in the cylinder head 43 . A cylinder head cover 44 is arranged on the cylinder head 43 in such a manner as to cover the valve operating mechanism 35 .

To transmit power to the valve operating mechanism 35 in the cylinder head cover 44, an endless cam chain (not shown) is disposed in a cam chain chamber (not shown) and travels around the camshaft 36 and the crankshaft 41, wherein the cam A chain chamber is defined in the crankcase 30 a, the cylinder block 42 and the cylinder head 43 on one side thereof at one end of the crankshaft 41 . When power is transmitted from the crankshaft 41 to the camshaft 36 through the endless cam chain, the camshaft 36 rotates synchronously with the crankshaft 41 at half the speed of the crankshaft 41 .

A spark plug (not shown) is fitted in the cylinder head 43 and inserted into a combustion chamber 49 on the other side of the cylinder head 43 at the other end of the crankshaft 41 .

An intake port 45 and an exhaust port 46 are defined in a cylinder head 43 on a cylinder block 42 whose cylinder axis C is inclined forward so as to be placed almost horizontally. The intake port 45 and the exhaust port 46 have ends that open at the combustion chamber upper limit surface 43a, and are bent and extend in directions vertically away from each other.

The intake port 45 has an upstream end that opens upward from the cylinder head 43 and is connected to the intake pipe 7 constituting a continuous intake passage 70 . A throttle body 9 is connected to a curved and rearwardly extending upstream end of the intake pipe 7 .

The exhaust port 46 has a downstream end that opens downward from the cylinder head 43 and is connected to the exhaust pipe 6 (see FIG. 1 ).

The tubular intake valve guide 37i fits in the curved outer wall 45a of the cylinder head 43, which defines the intake port 45 therein. The intake valve 38i is slidably supported by a tubular intake valve guide 37i to open and close an intake valve opening 47 defined in the cylinder head 43 and through which the intake port 45 communicates with the combustion chamber 49 .

The tubular exhaust valve guide 37e fits in the curved outer wall 46a of the cylinder head 43 which defines the exhaust port 46 therein. The exhaust valve 38e is slidably supported by a tubular exhaust valve guide 37e to open and close an exhaust valve opening 48 defined in the cylinder head 43 and through which the exhaust port 46 communicates with the combustion chamber 49 .

The intake valve 38i and the exhaust valve 38e are normally urged to move upward by the valve spring 34 so that their valve heads close the intake valve opening 47 and the exhaust valve opening 48 respectively. As shown in FIG. 2, when the rod ends of the intake valve 38i and the exhaust valve 38e are respectively held by the intake rocker arm 39i and the exhaust rocker arm 39i and the exhaust cam 36e on the camshaft 36, When the arm 39e is depressed and caused to swing, the intake valve 38i and the exhaust valve 38e are moved axially to open the intake valve opening 47 and the exhaust valve opening 48 at predetermined timings, thereby allowing the intake port 45 And the exhaust port 46 is in fluid communication with the combustion chamber 49 to introduce the air-fuel mixture into the combustion chamber 49 and exhaust the combustion gas from the combustion chamber 49 at predetermined timing.

According to the present embodiment, as shown in FIG. 2 , the throttle body 9 made of metal is fastened to the upstream end of the intake pipe 7 connected to the intake port 45 in the cylinder head 43 .

The upstream end of the throttle body 9 is connected to an air cleaner 91 through a connection pipe 90 made of a resin material. When the power unit 3 swings and vibrates, the intake pipe 7 tends to be subjected to upward, downward, leftward and rightward vibration loads, especially upward, downward, leftward and rightward bending moments, including due to being fastened to The load caused by the weight of the throttle body 9 of the intake pipe 7 .

In view of these vibration loads, as shown in FIG. 2 , the intake duct 7 includes upper and lower ribs 71 and 72 standing respectively on its upper and lower surfaces and extending in the direction in which intake air flows through the intake duct 7 .

As shown in FIGS. 3 and 4 , the intake duct 7 also includes left and right reinforcing ribs 73 and 74 erected on its left and right surfaces, respectively, and extending along the direction in which intake air flows through the intake duct 7 .

As shown in FIG. 2, the intake pipe 7 includes a cylinder head side flange 75 on its downstream end serving as a joint point 7a connected to the inlet of the intake port 45 in the cylinder head 43 and on its upstream end serving as a connection Throttle body side flange 76 to the junction point of the throttle body 9 . It will be noted from FIGS. 6 to 8 that the intake pipe 7 is bent rearwardly from the cylinder head side flange 75 towards the throttle body side flange.

The internal combustion engine 4 incorporating the present embodiment also includes a fuel injection device 8 having an injector 81 at the upper portion of the intake pipe 7 . The fuel injection device 8 injects fuel into the intake port 45 .

As shown in FIGS. 3 and 4 , the fuel injection device 8 includes: an injector 81 ; an injector mounting base 80 through which the injector 81 is installed on the intake pipe 7 ; and a fuel connector 83 , The fuel connector 83 is attached to the injector 81 .

5 is a sectional view of cylinder head 43 and cylinder head side flange 75 of intake pipe 7 seen along line V-V in FIG. 3 , including axes x1 and x2 of injector side mounting holes 84A and 84B.

In FIGS. 2 to 5 , the fuel injection device 8 is shown as dense dots, and the intake pipe 7 is shown as sparse dots, so that they can be easily visually distinguished from each other.

As shown in FIG. 5 , the injector 81 installed on the intake pipe 7 through the injector mounting base 80 is assembled and inserted into the injector insertion hole 77 defined in the right rib 74 of the intake pipe 7 . and the upper rib 71 in the cylinder head side flange 75 . The injector 81 is fastened to the intake pipe 7 by bolts 78A and 78B which are respectively inserted into and pass through injection side mounting holes 84A and 84B defined in the injector mounting base 80 . Extension to the left. Bolts 78A are screwed into intake pipe side fastening holes 79A defined between the upper rib 71 and the left rib 73 in the cylinder head side flange 75 of the intake pipe 7 . Bolts 78B are inserted through intake pipe side fastening holes 79B defined in cylinder head side flange 75 between upper rib 71 and left rib 73 of intake pipe 7 .

The intake pipe side fastening hole 79A is an internally threaded hole. The injector mounting base 80 is fastened to the intake pipe 7 by bolts 78A inserted in the injection side mounting holes 84A and screwed into the intake pipe side fastening holes 79A.

The intake pipe side fastening hole 79B is a through hole that doubles as a hole through which the intake pipe 7 is fastened to the cylinder head 43 . The bolt 78B inserted through the injection side mounting hole 84B is inserted through the intake pipe side fastening hole 79B and screwed into the intake pipe fixing female screw hole 43B defined in the cylinder head 43 . The injector mounting base 80 of the fuel injection device 8 and the intake pipe 7 are thus fastened together to the cylinder head 43 by the bolt 78B.

The intake pipe 7 is further fastened to the cylinder head 43 by bolts 78C inserted through intake pipe side fastening holes 79C (see FIG. 7 ) defined in the cylinder head side flange 75 and screwed into inner holes defined in the cylinder head 43 . in threaded hole 43C.

According to the present embodiment, the upper rib 71, the lower rib 72, the left rib 73 and the right rib 74 of the intake pipe 7 increase the rigidity and mechanical strength of the intake pipe 7 against the vibration generated by and in the intake pipe 7. Strength, thereby increasing the vibration control capability of the intake pipe 7. Since the injector 81 is provided at a position between the upper rib 71 and the right rib 74, even if the upper rib 71 is provided on the intake pipe 7, the injector 81 is arranged so as not to be in contact with the upper rib 71 and the left rib 73 and the right rib 74. Physical interference occurs.

Since the injector side mounting holes 84A and 84B are provided between the upper rib 71 and the left rib 73 , the injector 81 and the injector side mounting holes 84A and 84B are positioned on the left and right sides of the upper rib 71 , respectively. Therefore, the ribs 71 to 74 for making the intake pipe 7 resistant to vibration from the motorcycle 1 are provided on the intake pipe 7 without physically interfering with the injector 81 and the injector-side mounting holes 84A and 84B.

Alternatively, the injector 81 may be positioned between the upper rib 71 and the left rib 73 with the injector side mounting holes 84A and 84B positioned between the upper rib 71 and the right rib 74 .

FIG. 6 is a vertical sectional view of the intake duct 7 shown in FIG. 2 , wherein the intake duct 7 is shown in the same orientation as in FIG. 2 .

FIG. 7 is a plan view of the intake pipe 7 mounted on the motorcycle 1 seen along line VII-VII of FIG. 6 . FIG. 8 is a bottom view of the intake pipe 7 mounted on the motorcycle 1 seen along line VIII-VIII of FIG. 6 .

The upward, forward, rightward and leftward directions of the motorcycle 1 are shown in FIGS. 6 to 8 .

As shown in FIGS. 2, 6 and 7, the throttle body 9 is arranged upstream of the intake pipe 7, and the lower rib 72, the left rib 73 and the right rib 74 respectively have a direction toward the downstream along the direction in which the air flows through the intake pipe 7. Lateral progressively higher rib heights h72, h73 and h74.

Even when a load due to the weight of the throttle body 9 made of metal and its vibration is applied to the intake pipe 7 from the throttle body 9 connected to the upstream end of the intake pipe 7, since the rib height is toward the downstream side where the load moment is higher Gradually higher, so the resistance and mechanical strength of the intake pipe 7 against the load moment increase toward the downstream side, allowing the intake pipe 7 to be stably supported on the internal combustion engine 4 .

According to this embodiment, since the injector 81 of the fuel injection device 8 and the injector side mounting holes 84A and 84B in the injector mounting base 80 are provided on both sides of the upper rib 71, the upper rib 71 has a relatively limited rib height. h71. However, the rib height h1 is generally gradually larger toward the downstream side in the direction in which air flows through the intake duct 7 , which contributes to increasing the resistance and mechanical strength of the intake duct 7 against the load moment on the downstream side.

As shown in FIG. 7 , fastening holes 79C are formed in the cylinder head side flange 75 for fastening the intake pipe 7 to the cylinder head 43 . The bolt 78C is inserted through the fastening hole 79C, and is directly screwed into the internally threaded hole 43C defined in the cylinder head 43 without passing through the injector side mounting hole, thereby fastening the intake pipe 7 to the cylinder head 43 (see FIG. 5 ).

The effects obtained from the layout and shape of the ribs 71 to 74 on the intake pipe 7 and the layout of the injector side mounting holes 84A and 84B in the injector 81 of the fuel injection device 8 and the injector mounting base 80 are not limited to The internal combustion engine 4 of the swingable power unit 3 used on the scooter 1, the cylinder axis C of the internal combustion engine is inclined forward to be almost horizontal.

The same effect also applies to an internal combustion engine whose cylinder axis is inclined slightly forward from a vertical plane, used in a motorcycle (such as an LMC (Light Motorcycle) car)) for use.

In those alternative applications, the power unit is non-pivotably mounted on the vehicle body frame. However, the effects obtained according to the above-described embodiments are also applicable because the saddle-type vehicle itself is swingable and vibrated.

Specifically, the upper rib 71, lower rib 72, left rib 73, and right rib 74 of the intake duct 7 increase the rigidity and mechanical strength of the intake duct 7 against vibrations generated by and in the intake duct 7, thereby The vibration control capability of the intake pipe 7 is increased. Since the injector 81 is provided at a position between the upper rib 71 and the right rib 74 or between the upper rib 71 and the left rib 73, even if the upper rib 71 is provided on the intake pipe 7, the injector 81 is arranged so as not to be in contact with the upper rib 71. The rib 71 , the left rib 73 and the right rib 74 physically interfere.

However, the present invention is particularly useful when applied to the internal combustion engine 4 of the swingable power unit 3 on the scooter 1 as exemplified by the above-described embodiments. In this case, the internal combustion engine 4 is included in the swingable power unit 3 mounted on the vehicle body frame 2 so that the internal combustion engine 4 can vertically swing together with the rear wheels 15, wherein the cylinder axis C The longitudinal direction of the vehicle 1 is oriented, and the intake pipe 7 is bent and extends rearward from a joint point 7 a between the intake pipe 7 and the cylinder head 43 .

In the swingable power unit 3 in which the intake pipe 7 is bent and extends rearward from the joint point 7a between the intake pipe 7 and the cylinder head 43, even if the distance between the cylinder head 43 and the throttle body 9 is greater than a predetermined value by For increasing the power output value of the internal combustion engine 4 in the low and middle rotational speed range, the upper rib 71 , lower rib 72 , left rib 73 and right rib 74 of the intake pipe 7 effectively increase the resistance of the intake pipe 7 to the The vibration and the rigidity and mechanical strength of the vibration generated in the intake pipe 7, thereby increasing the vibration control ability of the intake pipe 7, and even if the upper rib 71 is provided on the intake pipe 7, the injector 81 is arranged so as not to be in contact with the rib 71 to 74 Physical interference occurs.

As shown in FIG. 8 , the cylinder head side flange 75 positioned downstream and connected to the intake pipe 7 of the cylinder head 43 has a larger connection area Sb than the throttle body side flange 76 positioned upstream and connected to the throttle body 9 . Large connection area Sa.

Therefore, even though the throttle body 9 connected to the upstream end of the intake pipe 7 is relatively heavy, the intake pipe 7 is stably supported on the swingable power unit 3 .

As shown in FIGS. 2, 6 and 7, the greater the curvature of the intake pipe 7, the greater the rib heights h71 and h72 of the upper rib 71 and the lower rib 72, except for the peripheral area 77a around the injector insertion hole 77, Among them, the injector 81 is inserted into the injector insertion hole 77 .

In other words, the swingable power unit 3 in which the intake duct 7 is curved can give the intake duct 7 a higher vibration control capability by increasing the rib heights h71 and h72 according to the curvature of the intake duct 7 .

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the illustrated embodiments, but various changes and modifications can be made in the embodiments within the scope of the present invention. For example, the power unit and internal combustion engine according to the present invention are not limited to those on motorcycles, but are widely applicable to power units and internal combustion engines on other types of saddle vehicles.

For purposes of illustration, the layout of various components in the left and right directions has been described in accordance with the illustrated embodiment. However, components may be arranged according to the reverse layout in the left and right directions.

[List of Reference Signs]

1 Motorcycle 2 Vehicle body frame

3 Power unit or pivotable power unit 4 Internal combustion engine

5 power transmission component 7 intake pipe

7a Junction 8 Fuel injection unit

9 Throttle body 15 Rear wheel

22 main frame 22a lower frame

22b Inclined section 22c Horizontal section

23 Power unit support bracket 24 Connecting rod

30 Power unit housing 30a Crankcase

30L Left Half Case 41 Crankshaft

42 Cylinder block 42a Cylinder bore

43 Cylinder head 43a Combustion chamber upper surface

43B Inlet pipe fixing internal thread hole 45 Air inlet

47 Intake valve opening 49 Combustion chamber

51 Belt type continuously variable transmission 52 Reducer gear mechanism

70 Air intake channel 71 Upper rib

72 lower rib 73 left rib

74 Right rib 75 Cylinder head side flange

76 Throttle body side flange 77 Injector insertion hole

77a Peripheral area around insertion hole 78A Bolt

78B Bolt 78C Bolt

79A Intake pipe side fastening hole 79B Intake pipe side fastening hole

79C Intake pipe side fastening hole 80 Injector mounting base

81 Injector 82 Control terminal

83 Fuel connector 84A Injector side mounting hole

84B Injector side mounting hole 90 Connecting tube

91 Air filter C Cylinder axis

h71 (upper rib 71) rib height

h72 (lower rib 72) rib height

h73 (left rib 73) rib height

h74 (right rib 74) rib height

Sa Connection area of cylinder head side flange 75

Sb Connection area for throttle body side flange 76

Claims (6)

1. a kind of air intake structure of the internal combustion engine for using on saddle vehicle, the air intake structure has to be erect respectively In the upper surface of the air inlet pipe (7) of engine (4), lower surface, left surface, upper rib at right surface, lower rib, left rib, right rib (71,72,73,74), in which:

Injector (81) is arranged between one of the left rib (73) and the right rib (74) and the upper rib (71).

2. the air intake structure of the internal combustion engine according to claim 1 for being used on saddle vehicle, in which:

The internal combustion engine (4) is included in swingable power unit (3), swingable power unit (3) peace To be swung together with rear-wheel (15) on vehicle body frame (2), wherein edge cylinder-bore axis (C) of the engine (4) The vehicle it is machine-direction oriented；And

Air inlet pipe (7) bending and the engagement between the air inlet pipe (7) and the cylinder head (43) of the engine (4) The rear of point (7a) Xiang Suoshu vehicle extends.

3. the air intake structure of the internal combustion engine according to claim 1 or 2 for being used on saddle vehicle, in which:

Injector side mounting hole (84A, 84B) setting the other of the left rib (73) and the right rib (74) with it is described on Between rib (71), and the injector (81) and injector side mounting hole (84A, 84B) are separately positioned on the upper rib (71) in left and right side.

4. according to claim 1 to the internal combustion hair described in any one claim in 3 for being used on saddle vehicle The air intake structure of motivation, in which:

Throttle body (9) is arranged in the upstream of the air inlet pipe (7)；And

At least described lower rib (72), the left rib (73) and the right rib (74), which have, flows through the air inlet pipe along air (7) direction is towards downstream side gradually bigger corresponding rib height (h72, h73, h74).

5. the air intake structure of the internal combustion engine according to claim 4 for being used on saddle vehicle, in which:

The air inlet pipe (7) has downstream part, and the downstream part is connected to cylinder head (43) and has than the air inlet The big join domain (Sa) of the join domain (Sb) of the upstream portion for being connected to the throttle body (9) of pipe.

6. the air intake structure of the internal combustion engine according to claim 4 or 5 for being used on saddle vehicle, in which:

The upper rib (71) and the lower rib (72) have respective rib height (h71, h72), so that the song of the air inlet pipe (7) Rate is bigger, and the rib height (h71, h72) is bigger, but is inserted into except the neighboring area (77a) around hole, the injector (81) it inserts in the hole described in insertion.