JP7241235B2 - Intake device for internal combustion engine for straddle-type vehicle - Google Patents

Description

The present invention relates to an intake system for an internal combustion engine mounted on a vehicle, particularly a straddle-type vehicle.

In the intake passage of the internal combustion engine, an intake control valve is provided downstream of the throttle valve to control the supply of intake air to one side of the intake passage divided into two to generate a vortex such as a tumble flow in the air-fuel mixture in the combustion chamber. An additional intake device is disclosed, for example, in Patent Document 1 below.
However, in Patent Document 1 below, although the concept of an intake system is shown, when an internal combustion engine mounted on a saddle type vehicle is provided with an intake control valve such as a tumble control valve in addition to a throttle valve, both valves Although the weight of the system increases and the throttle valve in particular becomes susceptible to vibrations, the specific configuration and layout of the intake system that provides the vehicle with vibration resistance and heat resistance against the heat from the internal combustion engine is shown. do not have.
Further, Patent Document 2 below discloses a system in which a rubber insulator is interposed between a throttle valve and an intake pipe. , the problem and countermeasures when both valves are provided are not shown.

Japanese Patent Application Laid-Open No. 2008-057463 (Fig. 1) Japanese Patent No. 5768681 (Figs. 5 to 8)

The present invention has been made in view of such prior art, and provides seismic resistance and seismic resistance to vibrations in a vehicle when an intake control valve such as a tumble control valve is provided in addition to a throttle valve in an internal combustion engine for a straddle-type vehicle. An object of the present invention is to provide an air intake device that can obtain heat resistance against heat from an internal combustion engine.

In order to solve the above problems, the present invention
A throttle valve provided in an intake passage through which intake air to the combustion chamber of the internal combustion engine passes and is controlled to an arbitrary opening to control the amount of intake air; and a throttle valve provided downstream from the throttle valve and along the passage direction. an internal combustion engine for a saddle-ride type vehicle, comprising: an intake control valve for opening and closing a cross section of the main passage of the intake passage divided into a main passage and a sub passage to control intake air supply to the main passage. wherein at least part of the intake passage between the throttle body having the throttle valve and the intake control valve device having the intake control valve is formed, has heat insulating properties, and the throttle body and An intake system for an internal combustion engine for a straddle-type vehicle, characterized by comprising a connection pipe having elasticity that allows relative displacement with the intake control valve system.

According to the above configuration,
An intake system comprising in series a throttle valve and an intake control valve for controlling the supply of intake air to the main passage of an intake passage divided into a main passage and an auxiliary passage, wherein the throttle body having the throttle valve and the intake control valve Since a connecting pipe having heat insulating properties and elasticity is provided between the throttle valve and the intake control valve device provided with the throttle valve, the vibration resistance of the throttle valve against vibration of the vehicle and the heat resistance against heat from the internal combustion engine are improved.

According to a preferred embodiment of the invention,
When viewed from the side, the actuator of the throttle valve is provided at a position overlapping the main frame of the straddle-type vehicle, and the throttle body and the intake control valve device are directly connected by the connecting pipe having heat insulation and elasticity. be.
In this way, the intake passage length can be reduced by connecting the throttle body and the intake control valve device only with a connecting pipe having heat insulation and elasticity, and the main frame is arranged near the rear of the intake port. However, by positioning the throttle valve actuator on the side of the main frame, the intake passage can be arranged to avoid the main frame. Layout is improved.

According to a preferred embodiment of the invention,
A fuel injection valve is arranged upstream of the connecting pipe in the intake passage, and the center axis direction of the fuel injection valve is directed downstream of the connecting pipe on the inner surface of the intake passage.
Therefore, at the connection between the inner surface of the air passage of the throttle body equipped with the throttle valve and the inner surface of the connecting pipe, or the connection between the inner surface of the connecting pipe and the inner surface of the air passage of the intake control valve device equipped with the intake control valve, It is possible to prevent fuel from accumulating in the generated stepped portion.

According to a preferred embodiment of the invention,
A downstream side of the air passage of the intake control valve device descends toward the combustion chamber. Therefore, dripped fuel injected by the fuel injection valve is guided to the downstream side of the air passage, and backflow of fuel to the upstream side can be prevented.

According to a preferred embodiment of the invention,
The connection pipe is formed of a rubber member and includes a throttle valve side portion connected to the throttle body, an intake control valve side portion connected to the intake control valve device, the throttle valve side portion and the intake control valve side portion. and an intermediate portion defining an annular wall formed between and, said annular wall having a flexure. Therefore, the connecting pipe made of a rubber member that connects the throttle body, which is relatively heavy, to the intake control valve device is provided with a relief allowance due to the bending against the load, and the durability can be improved.

According to the intake device for an internal combustion engine for a straddle-type vehicle of the present invention,
An intake system comprising in series a throttle valve and an intake control valve for controlling the supply of intake air to the main passage of an intake passage divided into a main passage and an auxiliary passage, wherein the throttle body having the throttle valve and the intake control valve Since a connecting pipe having heat insulating properties and elasticity is provided between the throttle valve and the intake control valve device provided with the throttle valve, the vibration resistance of the throttle valve against vibration of the vehicle and the heat resistance against heat from the internal combustion engine are improved.

1 is a right side view of a motorcycle according to an embodiment of the present invention; FIG. FIG. 2 is a right side sectional view of the internal combustion engine mounted on the motorcycle in FIG. 1; FIG. 2 is a plan cross-sectional view of the main central portion of the motorcycle taken along the line III-III in FIG. 1; FIG. 4 is a right side perspective view of the main central part of the motorcycle, viewed obliquely from above on the right side, with the fuel tank, seat, and rear side cover removed, and the surroundings of the tumble valve device, throttle body, and connecting tube, viewed from arrow IV in FIG. 3 ; . FIG. 4 is an elevation cross-sectional view of the main central portion of the motorcycle taken along line VV in FIG. 3; 6 is an enlarged perspective view of the outer shape of the elastic insulator in FIG. 5. FIG.

An intake system for an internal combustion engine for a straddle-type vehicle according to one embodiment of the present invention will be described with reference to FIGS. 1 to 6. FIG.
In this embodiment, the internal combustion engine is mounted on a straddle-type vehicle, and in this embodiment, the straddle-type vehicle is a motorcycle.
It should be noted that the front, rear, left, right, up and down directions in this specification and claims follow the directions of a straddle-type vehicle such as a motorcycle equipped with the internal combustion engine of the present embodiment. In the drawing, an arrow FR indicates the front of the vehicle, LH the left of the vehicle, RH the right of the vehicle, and UP the upper of the vehicle.

FIG. 1 is a right side view of a motorcycle 1 according to an embodiment of the invention.
FIG. 2 is a right side sectional view of the internal combustion engine 3 mounted on the motorcycle 1 in FIG.
A body frame 2 of a motorcycle (a "straddle-type vehicle" in the present invention) 1 includes a head pipe 20 forming a front end, and after extending rearwardly downward from the head pipe 20, it curves and further extends downward. A single main frame 21 having a drooping portion 21a, a pair of left and right seat rails 22 extending rearward from the curved portion of the main frame 21, and a single down rail extending downward from the head pipe 20 at the center of the vehicle width. A frame 23, a pair of left and right pivot plates 24 attached to the lower part of the drooping portion 21a of the main frame 21, and a pair of left and right pivot plates 24 extending rearwardly upward and connected to approximately the central portion of the seat rail 22 in the vehicle front-rear direction. A rear frame 25 is provided.

A front fork 12 supporting a front wheel 11 is rotatably attached to the lower portion of the head pipe 20, and a fuel tank 13 is attached to the main frame 21. As shown in FIG. A swing arm 14 is supported on the pivot plate 24 so as to be vertically swingable. A seat 15 and a pair of left and right rear side covers 10a are attached to the seat rails 22. As shown in FIG.

In front of the head pipe 20, a front cowl 10b integrally provided with headlights, front blinkers, etc. is supported. A front fender 10c that covers the front wheel 11 from above is supported on the lower portion of the front fork 12. As shown in FIG. The swing arm 14 rotatably supports a rear wheel 16 at its rear end. A lower end of the rear cushion unit 17 is attached to the rear portion of the swing arm 14 , and an upper end of the rear cushion unit 17 is attached near the joint between the rear frame 25 and the seat rail 22 .

The seat 15 is formed as a two-person tandem seat elongated in the front-rear direction on which the driver and the fellow passenger can sit. Below the pivot plate 24, a side stand 19 for parking the motorcycle 1, a center stand (not shown), a step 18A for the rider to put his feet on, a step bracket 18C for supporting a pillion step 18B for the passenger to put his feet on, etc. is attached.

An engine hanger 26 is fixed to the lower portion of the down frame 23 , and the engine hanger 26 and a pair of left and right pivot plates 24 support a power unit 4 integrally including the internal combustion engine 3 and the transmission 5 .
The internal combustion engine 3 includes a crankcase 30 that houses a crankshaft 31, and a cylinder portion 32 that is fastened to the upper portion of the crankcase 30 with the cylinder axis X slightly inclined forward.
The cylinder portion 32 includes a cylinder block 33, a cylinder head 34, and a head cover 35 in order from the crankcase 30 side.
The internal combustion engine 3 is arranged within a region surrounded by the main frame 21 and the down frame 23 in a side view.

The cylinder block 33 is attached to the crankcase 30 so as to tilt slightly forward and stand up.
A throttle body 8 is connected to the rear surface of the cylinder head 34 via a tumble valve device ("intake control valve device" in the present invention) 7, and an air cleaner 86 is connected upstream of the throttle body 8 via a connecting tube 85. be.

An exhaust pipe 39 is connected to the front surface of the cylinder head 34 and a muffler 40 is connected to the downstream side of the exhaust pipe 39 .
The air cleaner 86 is arranged within a triangular area in a side view surrounded by the seat rails 22, the main frame 21 and the rear frame 25. As shown in FIG.
The left and right sides of the upper half of the air cleaner 86 are covered with a pair of left and right rear side covers 10a made of a resin material.

The rear side cover 10a overlaps a portion of the rear portion of the fuel tank 13 in a side view, extends rearward from the rear portion of the fuel tank 13, extends below the seat 15, and extends to the rear lower end of the seat 15. As shown in FIG. As shown in FIG. 1, the rear side cover 10a covers the rear lower portion of the fuel tank 13 and the lower edge of the seat 15 so that they cannot be seen from outside, thereby improving the appearance. In addition, the rear side cover 10a covers the outer side of the seat rail 22 in the vehicle width direction, thereby improving the appearance.
In addition, the code|symbol 10d is a rear fender in FIG.

FIG. 2 is a right side cross-sectional view of the power unit 4 taken out of FIG. 1 and shown in substantially the same orientation as shown in FIG.
The internal combustion engine 3 in the power unit 4 has a cylinder block 33, a cylinder head 34, and a head cover 35 which form a cylinder portion 32. As shown in FIG. ing.
The left case half 30L of the crankcase 30 is shown with the mating surface 30b for the right case half (not shown) facing forward.

A transmission 5 having a main shaft 51 and a counter shaft 52 parallel to the crankshaft 31 is provided inside the rear portion of the crankcase 30 .
The rotation of the crankshaft 31 accompanying the operation of the internal combustion engine 3 is transmitted to the main shaft 51 via a transmission clutch (not shown), and is changed by a transmission gear group (not shown) provided on the main shaft 51 and the counter shaft 52 to produce a counter. It is transmitted to the shaft 52.
The counter shaft 52 is an output shaft of the internal combustion engine 3, that is, of the power unit 4, and includes a drive sprocket 53 fitted on the left shaft end of the counter shaft 52 and a driven sprocket 54 fitted on the rear wheel shaft 16a. A drive chain 55 is stretched between them, and the rear wheels 16 are driven to run.

A piston 36 that reciprocates within a cylinder bore 33 a of the cylinder block 33 is connected to a crank pin 31 a of the crank shaft 31 by a connecting rod 37 .
A combustion chamber 38 is formed between a top surface 36a of a piston 36 slidably fitted in a cylinder bore 33a of a cylinder block 33 and a combustion chamber ceiling surface 34a of a cylinder head 34 facing the top surface 36a. be done.

In this embodiment, the internal combustion engine 3 employs a single-cylinder SOHC type two-valve system, and a valve mechanism 9 is provided in the cylinder head 34 .
A head cover 35 is overlaid on the cylinder head 34 so as to cover the valve mechanism 9 .
An endless cam chain (not shown) connects the crankcase 30, the cylinder block 33, and the cylinder head 34 to one side of the crankshaft 31 in the direction of the crankshaft 31 (in this embodiment, the 2 opposite side in the figure), it is hung between the camshaft 91 and the crankshaft 31 through a cam chain chamber (not shown). to rotate.
In the cylinder head 34, an ignition plug 88 is inserted into the combustion chamber 38 from the side opposite to the cam chain chamber (the other side in the direction of the crankshaft 51, the front side in FIG. 2 in this embodiment) ( See Figure 4).

In the cylinder head 34 of the cylinder portion 32 which is slightly forward inclined with respect to the cylinder axis X, an exhaust port 44 and an intake port 43 are separated from each other in the front-rear direction from the exhaust valve port 42 and the intake valve port 41 which open to the ceiling surface 34a of the combustion chamber. It is formed by extending while curving in the direction.
The upstream end of the intake port 43 opens toward the rear of the cylinder head 34 and is connected to a tumble valve device ("intake control valve device" in the present invention) 7 with a heat insulating plate member 62 interposed therebetween. A throttle body 8 is connected to the upstream side of the throttle body 8 via an elastic insulator (a "connecting pipe" in the present invention) 61 .
An air cleaner 86 is sequentially connected to the upstream side of the throttle body 8 via a connecting tube 85 (see FIG. 1).
That is, intake air from the air cleaner 86 is burned through the connecting tube 85, the air passage 80 of the throttle body 8, the air passage 60 of the elastic insulator 61, the air passage 70 of the tumble valve device 7, the opening 63 of the heat insulating plate member 62, and the intake port 43. A continuous intake passage 6 leading to chamber 38 is constructed.

The downstream end of the exhaust port 44 opens toward the front of the cylinder head 34 and is connected to the exhaust pipe 39. The exhaust pipe 39 wraps around below the power unit 4 and then extends to the muffler 40 on the right side of the rear wheel 16. (see Figure 1).

A cylindrical intake valve guide 45 is fitted integrally with the curved outer wall portion 43a of the intake port 43 in the cylinder head 34, and an intake valve 47 slidably supported by the intake valve guide 45 controls combustion of the intake port 43 The intake valve port 41 facing the chamber 38 is opened and closed.
Also, an exhaust valve 48 slidably supported by an exhaust valve guide 46 integrally fitted to the curved outer wall portion 44a of the exhaust port 44 in the cylinder head 34 faces the combustion chamber 38 of the exhaust port 44. Opening and closing the mouth 42.

The intake valve 47 and the exhaust valve 48 are urged upward by a valve spring 49 so that the head portions 47a and 48a of the intake valve 47 and the exhaust valve 48 close the intake valve port 41 and the exhaust valve port 42 facing the combustion chamber 38. Stem ends 47b and 48b of the intake valve 47 and the exhaust valve 48 are pushed down by an intake rocker arm 93 and an exhaust rocker arm 94 which contact and oscillate with the intake cam and the exhaust cam of the camshaft 91, and the intake valve 47 and the exhaust valve 47 are opened at a predetermined timing. The exhaust valve 48 opens, the intake port 43 communicates with the combustion chamber 38, and the exhaust port 44 communicates with the combustion chamber 38, and intake and exhaust are performed at predetermined timings.

In the internal combustion engine 3 of the present embodiment as described above, in order to obtain more favorable combustion in the combustion chamber 38, an intake device for giving a tumble flow T of the fuel-air mixture in the combustion chamber 38, that is, longitudinal rotation is configured.
The throttle body 8 is rotatably supported in the throttle body 8 by a throttle valve shaft 81a which is oriented substantially horizontally and perpendicular to the flow direction F of the air intake passage 80, that is, the intake passage 6, and is controlled to an arbitrary degree of opening. A throttle valve 81 is provided to variably control the passage area of the air passage 80 to control the amount of intake air and to open and close the air passage 80 .

The air passage 70 of the tumble valve device 7 is connected to the downstream side of the throttle valve 81 in the flow direction F of the intake passage 6. A tumble control valve (a tumble control valve in the present invention) is rotatably supported in the tumble valve device 7 by a tumble valve shaft (that is, an intake control valve shaft) 71a which is oriented and parallel to the throttle valve shaft 81a, and is controlled to an arbitrary degree of opening. "intake control valve") 71.

The intake passage 6 on the downstream side of the tumble control valve 71 is divided along the passage direction by a partition wall 65 into a main passage 6A and a tumble passage 6B as a sub passage. A tumble valve shaft 71a of the tumble control valve 71 is provided adjacent to the .
The tumble control valve 71 provided in the air passage 70 on the downstream side of the throttle valve 81 is of the butterfly type. shaped tumble valve plate (ie intake control valve plate) 71b.
The tumble control valve 71 is rotatable counterclockwise in the valve opening direction in FIG. It is biased in the clockwise direction to close the valve.

The throttle valve 81 provided in the intake passage 6 of the throttle body 8, i.e., the air passage 80, is also of the butterfly type. and a throttle valve plate 81b.
The throttle valve 81 is rotatable clockwise in FIG. 2 in the valve-opening direction, and is moved by a return spring (not shown) so that the throttle valve plate 81b is positioned at the fully closed position in contact with the inner surface 80a of the air passage 80. is biased counterclockwise in the valve closing direction.

In this embodiment, the intake passage 6 continues from the tumble valve device 7 to the intake port 43 and is vertically partitioned by a partition wall 65 to define a lower tumble passage (a "secondary passage" in the present invention). 6B and a main passage 6A except for the tumble passage 6B.
The partition wall 65 includes a tumble valve device side partition wall (that is, an intake control valve device side partition wall) 65A having an upstream end portion 65a, a heat insulating plate member side partition wall 65B, and an intake port side partition wall 65C. located and configured.

2, the cross section of the tumble passage 6B is changed by a partition wall 65 running vertically from the tumble valve device 7 to the intake port 43, as indicated by the two-dot chain lines A, B, and C. As shown in FIG.
That is, at the inlet of the intake port 43 near the upstream end 65a of the partition wall 65, the intake passage 6 is partitioned into upper and lower sides, and as shown in the cross section A, it is defined in a lower semicircular shape, As it progresses through the intake port 43, the cross section of the intake port side partition wall 65C changes in an arc shape as it progresses downstream, and as shown in the cross section B, the cross section is formed to have a circular cross section.
Further, the cross section of the tumble passage 6B is maintained in a circular cross section as shown in cross section C up to the downstream end of the intake port side partition wall 65C.

The center line Z of the tumble passage 6B from the cross section B to the cross section C is directed between the opening edge 41a of the intake valve port 41 on the side closer to the exhaust valve port 42 and the head portion 47a of the intake valve 47. set to point.
The throttle body 8 penetrates the intake passage 6 downstream of the throttle valve 81, that is, the ventilation passage 80 from the upper outside, and supplies fuel by injecting it obliquely toward the downstream side (schematically shown in FIG. 2). A fuel injection valve 87 arranged as indicated by injection line J) is attached.

Therefore, the intake air flowing through the tumble passage 6B is allowed to pass above the head portion 47a of the intake valve 47, and then flows into the cylinder bore 33a from between the intake valve port 41 and the opening edge 41a on the side closer to the exhaust valve port 42. , the tumble flow T can be easily generated in the combustion chamber . That is, the tumble passage 6B as a sub-passage serves as an air intake passage for generating the tumble flow T. As shown in FIG.

The tumble control valve 71 controls the main passage 6A of the upper and lower pair of the main passage 6A and the tumble passage 6B that divides the intake flow in the intake passage 6 on the downstream side by a tumble valve plate 71b provided above. It opens and closes the cross section of the passage to control intake air supply to the main passage 6A, and controls the distribution of intake air between the main passage 6A of the intake passage 6 and the tumble passage 6B which is a sub passage.
That is, in the closed position of the tumble control valve 71, the tumble valve plate 71b is positioned so as to cover the inlet opening 6Aa of the main passage 6A to block or suppress the inflow of the intake air, and the intake air is guided to the tumble passage 6B. , intake air from the tumble passage 6B flows into the cylinder bore 32a as an air-fuel mixture together with fuel from the fuel injection valve 87. As shown in FIG.

When the internal combustion engine 3 is operating at a low load, the throttle valve 81 is throttled and the amount of intake air is reduced. can be increased, and fuel combustion in the combustion chamber 38 can be favorably maintained while the tumble flow T of the intake air generated in the combustion chamber 38 is strengthened.
The tumble flow T indicated by the two-dot chain line in FIG. 2 schematically shows the tumble flow T in the combustion chamber 38 when the piston 36 descends inside the cylinder bore 33a as indicated by the two-dot chain line. .

Further, as the internal combustion engine 3 operates under a high load, the throttle valve 81 opens to increase the amount of intake air, but the tumble control valve 71 rotates in the opening direction to increase the inflow of intake air into the main passage 6A.
2, the throttle valve 81 and the tumble control valve 71 are positioned parallel to the flow direction F of the intake passage 6. A sufficient amount of intake air can flow through both the main passage 6A and the tumble passage 6B without being obstructed by the control valve 71, and together with the fuel from the fuel injection valve 87, can flow toward the combustion chamber 38 as an air-fuel mixture. can.

In this embodiment, the throttle valve 81 is turned by an engine control unit (ECU) (not shown) activating an actuator 82 of the throttle valve 81 based on the driver's operation and the state of the internal combustion engine 3, thereby positioning the valve. , is opened and closed.
In this embodiment, the actuator 82 is mainly composed of an electric motor. As shown in FIGS. 2 and 4, the throttle valve shaft 81a and the electric motor shaft, that is, the actuator shaft 82a are offset. is provided with an appropriate transmission portion 83 such as a gear mechanism (see FIG. 3).

The tumble control valve 71 is rotated by an engine control unit (ECU) (not shown) activating an actuator 72 of the tumble control valve 71 based on the state of the internal combustion engine 3 to position, open and close the valve. In this embodiment, the actuator 72 is mainly composed of an electric motor.

As shown in FIG. 3, which is a plan cross-sectional view of the main central portion of the motorcycle 1 taken along the line III-III in FIG. The tumble valve device 7 is fastened and connected with the heat insulating plate member 62 interposed therebetween.
The tumble valve device 7 is connected to the throttle body 8 via an elastic insulator 61 on the upstream side of the intake air flow, and further upstream to the throttle body 8 by connecting a connecting tube 85 to an air cleaner 86. In FIG. 1, the main body 8a (see FIGS. 1 and 2) having the air passage 80 of the throttle body 8 and the throttle valve 81 and the connecting tube 85 are located above the cross section III-III in FIG. Since it is positioned, it is indicated by a chain double-dashed line in FIG.

Therefore, in FIG. 3, with regard to the throttle body 8, the actuator 82 and the transmission part 83 to the throttle valve shaft 81a are shown in cross section. .
Also, with respect to the tumble valve device 7, the actuator 72, the air passage 70 and the tumble control valve 71 are shown in cross section.

4 is a view of the fuel tank 13, seat 15, and rear side cover 10a removed from FIG. 2 is a right side perspective view of the main central portion of the motorcycle 1. FIG.
In this embodiment, the upstream side of a connecting tube 85 connected to the upstream side of the main body 8a of the throttle body 8 having the throttle valve 81 is connected to the side surface 86b of the air cleaner 86, that is, the side facing the vehicle side.

When the tumble control valve 71 and the throttle valve 81 are provided in series between the cylinder portion 32 and the air cleaner 86 as in the present embodiment, the intake passage 6 passing through the tumble valve device 7 and the throttle body 8 becomes longer, and the connecting If the tube 85 were to be connected to the front surface 86a side of the air cleaner 86 as in the conventional art, the distance between the cylinder portion 32 and the air cleaner 86 would be set excessively long, resulting in an increase in the size of the vehicle body. If the connecting tube 85 itself, which has a pipe portion forming the intake passage 6 therebetween, or the connection of the tumble valve device 7 and the throttle body 8 is bent and the angle becomes steep, there is a risk that the intake performance will be affected.
However, since the upstream side of the connecting tube 85 is connected to the side surface 86b of the air cleaner 86, the connecting tube 85 can be smoothly connected even with the normal distance between the cylinder portion 32 and the air cleaner 86, and the flow of intake air becomes smooth. Since it is rectified, intake performance is improved.

Further, in this embodiment, as shown in FIG. 4, the tumble valve device 7 and the throttle body 8, which are fastened and connected to the intake port 43 at the rear of the cylinder head 34 with the heat insulating plate member 62 interposed therebetween, are connected as connecting pipes. are relay-connected by an elastic insulator 61 of .
That is, at least a part of the intake passage 6 between the throttle body 8 having the throttle valve 81 and the tumble valve device 7 having the tumble control valve 71 is configured, that is, fluidly relayed and heat insulating. In addition, an elastic insulator 61 is provided as a connection pipe having elasticity that allows relative displacement between the throttle body 8 and the tumble valve device 7 .

The elastic insulator (“connecting pipe” in the present invention) 61 is made of a rubber member having heat insulation and elasticity as a preferred example shown in this embodiment.
However, the elastic insulator 61 may be a mixture of metal members and resin members as long as it is a member having heat insulation and elasticity, and is configured in a connecting tube shape by connecting another member to the member having heat insulation and elasticity. may have been

That is, the intake passage 6 divided into the main passage 6A and the tumble passage 6B is provided with a tumble control valve 71 for controlling intake air supply to the main passage 6A and a throttle valve 81 for controlling the amount of intake air in series. In the air intake system, by providing an elastic insulator 61 having heat insulation and elasticity between the throttle body 8 having the throttle valve 81 and the tumble valve device 7 having the tumble control valve 71, the throttle valve 81 can be controlled by the vehicle. Seismic resistance against vibration and heat resistance against heat from the internal combustion engine 3 are improved.

Further, as described above, since the upstream side of the connecting tube 85 is connected to the side surface 86b of the air cleaner 86, the tumble valve device 7 and the throttle body 8 are arranged so that the direction of the intake passage 6 is left and right as shown in FIG. However, since the gap is connected by the elastic insulator 61, it can be easily dealt with by forming the ventilation path 60 of the elastic insulator 61 into a curved tube shape corresponding to it, and the ventilation path of the tumble valve device 7 70, the air passage 60 of the elastic insulator 61 and the air passage 80 of the throttle body 8 are smoothly connected, and the air intake passage 6 is smoothly constructed so that the air intake performance is not hindered.

Especially in the case of this embodiment, the throttle body 8 and the tumble valve device 7 are directly connected by the elastic insulator 61 having greater heat insulation and elasticity than the connection portion formed of a metal member. Tolerance of precision between and insulation is obtained. Further, as shown in FIG. 1, the actuator 82 of the throttle valve 81 is provided at a position overlapping the main frame 21 in a side view.
Thus, by connecting the throttle body 8 and the tumble valve device 7 only with the elastic insulator 61 having heat insulating properties and elasticity, the length of the intake passage can be suppressed, and the main frame 21 is located near the rear of the intake port 43. Even if it is arranged, the actuator 82 of the throttle valve 81 can be positioned on the side of the main frame 21 so that the intake passage 6 can be arranged while avoiding the main frame 21 . In addition, since it is not necessary to lengthen the main frame 21 unnecessarily in order to secure a space for the actuator 82, the layout is improved.

5 is an elevational view of the main central part of the motorcycle 1 including the intake passage 6 running vertically through the throttle body 8, the tumble valve device 7, and the elastic insulator 61 therebetween, as seen from the VV arrow in FIG. It is a sectional view.
As shown in FIG. 4, the tumble valve device 7 fastened and connected to the intake port 43 at the rear of the cylinder head 34 with the heat insulating plate member 62 interposed therebetween, and the main body 8a of the throttle body 8 are connected by an elastic insulator as a connecting pipe. 61 indicates relay connection.
The connecting tube 85 is behind the throttle body 8 (left side in the drawing), and is located on the right side (front side in the drawing) of the cross section VV in FIG.
The connecting tube 85, the air passage 80 of the throttle body 8, the air passage 60 of the elastic insulator 61, the air passage 70 of the tumble valve device 7, the opening 63 of the heat insulating plate member 62, and the intake port 43 form a continuous air intake passage 6. configured.

As shown in FIG. 5 , in the throttle body 8 , the fuel injection valve 87 is arranged upstream of the air passage 80 of the throttle body 8 , that is, the intake passage 6 , rather than the elastic insulator 61 .
The direction of the central axis I of the fuel injection valve 87 is directed downstream of the region of the elastic insulator 61 on the inner surface 6 a of the intake passage 6 . With such a setting, the connecting portion 64A between the inner surface 80a of the air passage 80 of the throttle body 8 having the throttle valve 81 and the inner surface 60a of the air passage 60 of the elastic insulator 61, or the air passage 60 of the elastic insulator 61 Fuel can be prevented from accumulating at a stepped portion 64B between the inner surface 60a of the tumble valve device 7 and the inner surface 70a of the air passage 70 of the tumble valve device 7 having the tumble control valve 71.

The downstream side (right side in FIG. 5) of the air passage 70 of the tumble valve device 7 descends toward the combustion chamber 38 side.
Therefore, dripping fuel injected by the fuel injection valve 87 is guided downstream of the air passage 70 and further flows down to the intake port 43, thereby preventing backflow of fuel to the upstream side.

FIG. 6 is an enlarged perspective view of the outer diameter of the elastic insulator 61 shown in FIG. 5, and is similar to the right side outer surface shown in FIG. 4, although the angle is slightly different.
The elastic insulator 61 is formed of a rubber member having heat insulation and elasticity as described above in this embodiment.
An air passage 60 that forms a part of the intake passage 6 and fluidly connects the throttle body 8 and the tumble valve device 7 is formed, and a throttle valve side portion connected to the downstream nozzle portion 8b of the throttle body 8 is formed. 61a, a tumble control valve side portion 61b connected to the upstream nozzle portion 7b of the tumble valve device 7, and an intermediate portion 61c forming an annular wall formed between the throttle valve side portion 61a and the tumble control valve side portion 61b. and

The throttle valve side portion 61a is fitted so as to cover the downstream side nozzle portion 8b of the throttle body 8, and its outer periphery is fastened and fixed with a binder 61d.
The tumble control valve side portion 61b is also fitted so as to cover the upstream nozzle portion 7b of the tumble valve device 7, and its outer periphery is fastened and fixed with a binder 61d.

Further, as shown in FIG. 6, the intermediate portion 61c has a flexible portion 67 forming a curved surface R. As shown in FIG. Therefore, an elastic insulator 61 made of a rubber member that connects the throttle body 8, which is relatively heavy, to the tumble valve device 7 is provided with a relief allowance by allowing the flexible portion 67 to easily and elastically bend against the load. , which improves the durability against vibration.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various design changes are possible without departing from the gist of the present invention. Of course, straddle-type vehicles, internal combustion engines, etc., include those implemented in various modes.
For convenience of explanation, the left-right arrangement of the illustrated embodiment has been described, but the present invention includes a different left-right arrangement as long as it is within the scope of the invention.

DESCRIPTION OF SYMBOLS 1... Motorcycle ("straddle-type vehicle" in this invention), 2... Body frame, 3... Internal combustion engine, 4... Power unit, 5... Transmission, 6... Intake passage, 6a... Inner surface, 6A... Main passage, 6Aa Inlet opening 6B Tumble passage ("auxiliary passage" in the present invention) 7 Tumble valve device ("intake control valve device" in the present invention) 8 Throttle body 8a Body 20 Head pipe 21 Main frame 21a Hanging part 23 Down frame 24 Pivot plate 26 Engine hanger 30 Crankcase 31 Crankshaft 32 Cylinder part 33 Cylinder block 33a Cylinder bore 34 Cylinder head 34a Ceiling surface of combustion chamber 36 Piston 36a Top surface 38 Combustion chamber 41 Intake valve port 41a Opening edge 42 Exhaust valve port 43 Intake port 43a Curved outer wall Parts 45... Intake valve guide 47... Intake valve 47a... Head portion 60... Air passage 60a... Inner surface a 61... Elastic insulator ("connection pipe" in the present invention) 61a... Throttle valve side portion 61b Tumble control valve side portion 61c Intermediate portion 62 Heat insulating plate member 63 Opening 64A Connection portion 64B Connection portion 65 Partition wall 65a Upstream end 65A Tumble valve device side partition Wall (intake control valve device side partition wall) 65B... Insulation plate member side partition wall 65C... Intake port side partition wall 67... Flexible portion 70... Ventilation path 70a... Inner surface 71... Tumble control valve (this invention 71a...Tumble valve shaft (intake control valve shaft), 71b...Tumble valve plate (intake control valve plate), 72...Actuator (of tumble control valve 71), 80...Air passage, 80a... Inner surface 81 Throttle valve 81a Throttle valve shaft 81b Throttle valve plate 82 Actuator (of throttle valve 81) 82a Actuator axis 85 Connecting tube 86 Air cleaner 87 Fuel injection valve X... Cylinder axis Y... Vehicle lateral center line Z... Center line (of tumble passage 6B from cross section B to cross section C) T... Tumble flow F... Flow direction (of intake passage 6) I... (Fuel injection valve 87) central axis, R: curved surface

Claims (5)

a throttle valve (81) provided in an intake passage (6) through which intake air to a combustion chamber (38) of the internal combustion engine (3) passes, and controlled to an arbitrary degree of opening to control the amount of intake air;
Passage cross section of the main passage (6A) of the intake passage (6) which is provided downstream from the throttle valve (81) and divided into a main passage (6A) and a sub passage (6B) along the passage direction. An intake device for an internal combustion engine for a straddle-type vehicle, comprising an intake control valve (71) for opening and closing the intake air to control the supply of intake air to the main passage (6A),
An intake control valve device (7) having the intake control valve (71) is connected to an intake port (43) that opens toward the rear of the cylinder head (34) and drives the intake control valve (71). The actuator (72) is positioned behind the cylinder section (32) of the internal combustion engine (3),
In a side view, the actuator (82) of the throttle valve (81) is provided at a position overlapping the main frame (21) of the straddle-type vehicle (1),
forming at least part of the intake passage (6) between the throttle body (8) having the throttle valve (81) and the intake control valve device (7) having the intake control valve (71), and heat insulating a connection pipe (61) having elasticity and having elasticity to allow relative displacement between the throttle body (8) and the intake control valve device (7);
An intake system for an internal combustion engine for a straddle-type vehicle, wherein the connecting pipe (61) has a flexible portion (67). The straddle-type vehicle according to claim 1, wherein the throttle body (8) and the intake control valve device (7) are directly connected by the connecting pipe (61) having heat insulation and elasticity. intake system for internal combustion engines. A fuel injection valve (87) is arranged upstream of the intake passage (6) from the connecting pipe (61),
2. The direction of the central axis (I) of the fuel injection valve (87) is directed downstream of the connection pipe (61) on the inner surface (6a) of the intake passage (6). 3. An intake system for an internal combustion engine for a straddle-type vehicle according to claim 2. 4. The internal combustion engine for a straddle-type vehicle according to claim 3, wherein a downstream side of the air passage (70) of the intake control valve device (7) descends toward the combustion chamber (38). air intake system. The connection pipe (61) is formed of a rubber member and has a throttle valve side portion (61a) connected to the throttle body (8) and an intake control valve side portion (61b) connected to the intake control valve device (7). ) and an intermediate portion (61c) forming an annular wall formed between the throttle valve side portion (61a) and the intake control valve side portion (61b),
5. The intake of the internal combustion engine for a straddle-type vehicle according to any one of claims 1 to 4, wherein the intermediate portion (61c) has the bending portion (67) forming a curved surface (R). Device.

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