JP2003176762A - Fuel hose mounting structure for fuel injection engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel hose mounting structure which improves the reliability of the connecting part of the fuel hose in a swing unit type fuel injection engine. <P>SOLUTION: A fuel injection engine having an injector is formed integrally with a decelerator coupled to a rear wheel to constitute an engine unit. The engine unit is pivotally fitted to a body frame 34. The engine unit and the rear wheels are pivotally attached to the body. A fuel tank 10 is arranged on the body frame 34. The fuel tank 10 and the injector are connected by a fuel hose 62. While the middle part of the fuel hose 62 is fixed to the body frame 34, the fuel hose 62 arranged between a fixing part (for example, a stay 63) to the body frame 34 of the fuel hose 62 and the injector is configured to be elastically deformed according to the swing motion of the engine unit. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel hose mounting structure for a swing unit type fuel injection engine.

[0002]

2. Description of the Related Art In a small motorcycle such as a scooter,
A swing unit type engine is used. In this swing unit engine, an engine unit is formed by integrally connecting an engine crankcase and a speed reducer case, a rear wheel is connected to the speed reducer, and a swing unit is attached to a vehicle body frame through a damper so that the engine unit The front part of the is pivotally attached to the vehicle body frame via a pivot. As a result, the engine unit can rotate together with the rear wheels within an angular range centered on the pivot, and swings with respect to the vehicle body frame to absorb vibration during traveling.

Such a swing unit type engine is described in, for example, Japanese Patent Application Laid-Open No. 2004-242242.

As a swing unit type engine for such a small motorcycle, a 2-cycle engine or a 4-cycle engine equipped with a carburetor or an injector can be used.

In the intake system of this engine, an air cleaner is provided at the end of the intake passage, and outside air is introduced through the air cleaner. A throttle body forming a part of the intake passage is connected in the middle of the intake passage. A throttle valve is provided in the throttle body to control the intake air amount. For example, in the case of a fuel injection type 4-cycle engine, an injector is provided facing the intake passage on the downstream side of the throttle body to inject fuel. The intake air that has been injected with fuel to become an air-fuel mixture is sucked into the engine combustion chamber through the intake manifold and the intake valve at the downstream end of the intake passage. In the case of a multi-cylinder engine, an injector is provided in the intake manifold corresponding to each cylinder.

This fuel injection type engine is provided with an injector on the intake passage, and the fuel in the fuel tank is pressurized to a high pressure by the fuel pump and supplied to the injector via the fuel hose. The fuel hose is made of a hard resin and connects the fuel tank and the injector, and a return pipe branches near the injector and communicates with the fuel tank. A pressure regulator is provided on the return pipe of the fuel hose branch near the injector. Fuel is maintained at a predetermined pressure by a pressure regulator and supplied to the injector, and excess fuel is returned to the fuel tank through a return pipe. Such a fuel piping structure has been conventionally used for a fuel injection engine of a four-wheeled vehicle.

Fuel injected from the injector is sent from a fuel tank fixed to the vehicle body frame to the injector through a fuel hose by a fuel pump also fixed to the vehicle body frame. In a fuel injection engine,
Since high-pressure fuel is sent, the fuel hose is made of a resin material having relatively high hardness and elasticity to some extent so as to withstand high pressure. Such a fuel hose is arranged while being bent and elastically deformed so as to avoid the body frame and peripheral parts around the engine. Therefore, the elastic force associated with the elastic deformation of the fuel hose acts as an initial load on the connection portion of the fuel hose.

[0008]

[Patent Document 1] Japanese Patent Laid-Open No. 2001-48081

[0009]

However, in a small scooter or the like, the space around the engine is small,
Further, in order to reduce the size and weight, it is not possible to increase the strength by enlarging the member of the connecting portion. Therefore, due to the elastic force of the initial load of the fuel hose, the reliability of the connection may gradually decrease with long-term use. In particular, in a swing unit type fuel injection engine, the injector oscillates together with the engine, so the fuel hose connected to it also oscillates, and in addition to the initial load, the stress due to the oscillating deformation also causes the fuel hose connection. Act on the department. For this reason, the risk of the reliability of the connection is further increased.

Further, a small motorcycle equipped with a swing unit type engine has a limited space around the engine as compared with a four-wheeled vehicle, has large restrictions on the fuel piping layout, and the engine itself swings with respect to the vehicle body. (For a small scooter, about 8 to 10 cm with respect to the vehicle body), the fuel piping structure of a conventional four-wheeled vehicle cannot be used as it is.

The present invention has been made in view of the above prior art, and an object of the present invention is to provide a fuel hose mounting structure in which the reliability of the connection portion of the fuel hose is improved in a swing unit type fuel injection engine.

If the present invention is applied to a motorcycle equipped with a swing unit type fuel injection engine having a particularly large space limitation, a fuel pipe structure capable of coping with engine swing can be obtained with a simple structure.

[0013]

In order to achieve the above object, in the present invention, a fuel injection engine having an injector is integrated with a reduction gear connected to rear wheels to form an engine unit. A fuel for a motorcycle, in which the engine unit is pivotally attached to the vehicle body together with the rear wheels, a fuel tank is provided in the vehicle body frame, and the fuel tank and the injector are connected by a fuel hose. In the hose mounting structure, while fixing the middle part of the fuel hose to the vehicle body frame, the fuel hose between the injector and the fixing part of the fuel hose to the vehicle body frame is elastic according to the swinging motion of the engine unit. A fuel hose mounting structure for a motorcycle, which is configured to be deformable.

According to this structure, when the fuel hose connected to the injector rocks as the injector provided in the engine rocks together with the engine, the midway portion of the rocking fuel hose is attached to the body frame. Since it is fixed, the fuel hose between this fixing portion and the fuel tank also provided on the vehicle body frame is held in a fixed state and does not swing. Therefore, the influence of the swing on the connection portion with the fuel tank is eliminated, the stress is not applied, and the reliability of the connection with the fuel tank is improved. Along with this, the fuel hose on the injector side from the fixed part is elastically deformed following the swing of the engine,
The stress due to the oscillating deformation is absorbed, and the stress on the connection portion with the injector hardly acts, and the reliability of the connection with the injector is improved.

In this case, if the middle part of the fuel hose is fixed to the vehicle body frame, and further the fuel hose near the injector connection part is fixed to the engine side such as an intake pipe near the injector, the fuel to the injector is fixed. Since the connecting portion of the hose swings together with the engine and the injector, no stress acts on the connecting portion due to the swinging, and the reliability of the connection with the injector is further enhanced.

A preferred configuration example is characterized in that the fuel tank and the injector are connected by only one fuel hose.

According to this structure, the number of pipes is reduced by forming the fuel pipe system of the returnless structure without the return pipe by using the single fuel hose for supplying the fuel from the fuel tank to the injector. Simplifies, and particularly in a swing unit type engine, which has a large space constraint, a simple piping layout can be obtained and assembly work can be facilitated.

In a further preferred configuration example, a fuel pump and a pressure regulator are provided in the fuel tank.

According to this structure, the fuel pump and the pressure regulator required for the fuel piping system are housed in the fuel tank, so that the space is effectively used, and the structure and the layout of parts in a narrow space around the engine are simple. Turn into.

In a further preferred configuration example, a stepped recess is formed on the upper surface of the fuel tank, and an insertion hole formed in this recess is inserted to dispose the fuel pump in the fuel tank. A part of the fuel hose is arranged in the recess.

According to this structure, the insertion hole is formed in the stepped recess on the upper surface of the fuel tank, and the fuel pump is arranged in the fuel tank through the insertion hole, so that the fuel pump can be easily put in and taken out during assembly and maintenance. In addition, the components such as the coupler on the upper surface of the fuel pump can be housed in the recessed portion, and a compact structure can be obtained without projecting to the upper surface or the side surface of the fuel tank. Along with this, a part of the fuel hose, for example, the connection end portion connected to the coupler is disposed in the stepped recess,
The fuel hose can be pulled out to the side of the fuel tank with a simple layout without protruding to the upper surface of the fuel tank.

In a further preferred configuration example, the fuel hose is made of rubber.

According to this structure, the use of the highly flexible rubber fuel hose allows the stress acting on the piping system to follow the swinging motion of the swing unit type engine which swings largely with respect to the vehicle body frame. Is absorbed, the piping and other members are protected, and a smooth fuel supply operation is maintained.

In this case, in particular, if a molded hose made of rubber for high pressure that withstands high pressure is used, not only flexibility is obtained, but also by pre-molding in accordance with the piping layout, it is possible to prevent The initial load on the connection portion due to the hose deformation is reduced, and the stress on the connection portion due to the rocking deformation is reduced. This further increases the reliability of the fuel hose connection.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an external view of a small motorcycle to which the present invention is applied.

The vehicle body 1 has a handle 2 at the front, and the handle 2 is connected to the front wheels 5 via a steering shaft 4 which passes through a head pipe 3. The body frame 6 is coupled to the head pipe 3. The vehicle body frame 6 forms a frame structure of the entire vehicle body. The front part of the vehicle body is covered with a cowling 7. The vehicle body 1 includes a vehicle body cover 8 from the outside of the vehicle body frame 6.
Covered with. A seat 9 is provided in the center of the vehicle body, a fuel tank 10 is provided below the seat 9, and a helmet box (a storage case) 11 is provided behind the fuel tank 10. The fuel tank 10 supplies fuel to an injector (not shown) via a fuel hose (not shown). A breather hose 12 is provided on the top of the fuel tank 10.
Is connected to one end and the other end is connected to the canister 13. The canister 13 is connected to an intake system (for example, a throttle body) via a purge hose 14. A throttle wire 15 is attached to a throttle grip (or lever) of a right handle portion (not shown) and is connected to a throttle valve of an intake system. Similarly, a brake cable 16 is attached to a brake lever (not shown) on the steering wheel, and the rear wheel 1
7 is connected to the brake cam shaft 18.

The engine unit 19 is attached to the vehicle body frame 6 at the center of the vehicle body. The engine unit 19
It is composed of an engine (not shown) and a speed reducer 24 integrally connected to a crankcase (not shown) of the engine. The engine unit 19 is rotatably suspended around a pivot 22 with respect to a lower body frame member 21 forming a part of the body frame 6 via an engine bracket 20. The rear wheel 17 is connected to the rear part of the engine unit 19, and the lower end of the damper 23 is pivotally mounted. The upper end of the damper 23 is pivotally attached to a rear body frame (not shown) that constitutes a part of the body frame 6. As a result, the engine unit 19 becomes swingable around the pivot 22 together with the rear wheel 17, and a swing unit type engine is formed.

An air cleaner 25 is provided above the speed reducer 24. The outside air intake opening 25a is provided at the front of the air cleaner 25.
Is provided, and a dustproof cover 26 made of rubber or resin is provided inside the vehicle body cover 8 so as to cover the opening. Two
7 is a stand and 28 is a kick lever.

2 and 3 are a side view and a plan view, respectively, showing the essential parts of a motorcycle equipped with the fuel injection engine according to the present invention. FIG. 4 is an enlarged view of the intake system part.

An engine 29 is provided below the fuel tank 10. The engine 29 is a four-cycle single cylinder engine equipped with a fuel injection injector. A crankcase (not shown) of the engine 29 is integrally coupled with a speed reducer 24 including, for example, a V-belt type continuously variable speed reducing mechanism, and constitutes a swing unit engine type engine unit 19 as a whole. The duct 30 is connected to the front part of the speed reducer 24, and the outside air is sucked from the open end 30a thereof to be supplied into the speed reducer 5 to cool the inside. A rear output shaft (not shown) of the speed reducer 24 is connected to an axle of the rear wheel 17.

An engine bracket 20 is integrally coupled to the front part of the swing unit engine type engine unit 19. A link plate 32 is pivotally attached to the engine bracket 20 via a shaft 31. The link plate 32 is connected to the lower body frame member 2 via the pivot 22.
1 is rotatably mounted.

A damper (shock absorber) 23 is provided at the rear of the engine unit 19. Damper 23
The upper end 33 is pivotally attached to the rear body frame member 34, and the lower end 35 is pivotally attached to a bracket 36 at the rear end of the engine unit 19. As a result, the engine unit 19 is swingably attached to the body frame about the pivot 22 on the front side thereof. As shown in FIG. 4, the cylinder 37 of the engine 29 is tilted forward almost horizontally. The crankshaft 38 has an arrow D along with the shaft 31 of the engine bracket 20 (FIG. 2) centering on the pivot 22.
Rocks like.

An intake manifold 39 communicating with an intake port (not shown) of the cylinder head is provided on the intake side of the engine 29.
Also, an intake pipe 40 (FIGS. 3 and 4) connected thereto is provided, and an exhaust pipe 41 (FIG. 3) is connected to the exhaust side. The intake pipe 40 is a bent elbow-shaped intake pipe, and as shown in FIG.
Are butted and fixed by two bolts 44. 45
Is a maintenance cover for the valve cam. The engine 29 is provided with a water temperature sensor 46 (FIGS. 3 and 4). The detection output signal of the water temperature sensor 46 is the water temperature signal cable 89 (FIG. 3).
And to the engine control unit 47 (FIG. 3) via the wire harness 72. Detection signal cables (not shown) for an intake air temperature sensor and an intake pressure sensor, which will be described later, are further connected to the engine control unit 47 via a wire harness 72, and a throttle valve (not shown) is controlled to open and close based on these detection data. To do.

A throttle body 48 is connected to the intake manifold 39 via the above-mentioned bent elbow-shaped intake pipe 40. The throttle body 48 is connected to the air cleaner 25 via a joint 49. The injector 50 is attached to the intake pipe 40.

A throttle valve (not shown) is mounted in the throttle body 48, and a diaphragm type suction piston 51 is mounted upstream of the throttle valve. As will be described later, the suction piston 51 has a diaphragm chamber 52 provided above the throttle body 48, and an atmosphere intake port (atmosphere opening end) 54 of an atmosphere passage 53 for introducing atmosphere into the diaphragm chamber 52 has a throttle. It is provided below the body 48. A throttle wire 15 connected to a throttle lever (not shown) or a throttle grip (not shown) is connected to a valve shaft of the throttle valve via a link 55.

The air intake opening 25a at the front of the air cleaner 25 has a dustproof cover 26 made of rubber or resin (see FIG. 1).
(Dotted line) is covered. A vehicle body cover is further attached to the outside of the dustproof cover 26. The air intake 54 of the suction piston 51 opens inside the dustproof cover 26.

A heater wax type auto choke 56 and an intake pressure sensor 57 are provided on the throttle body 48 adjacent to the suction piston 51 (FIG. 3). The auto choke 56 opens and closes a bypass pipe (not shown) that connects the upstream side and the downstream side of the throttle valve. The intake pressure sensor 57 communicates with the intake manifold 39 or the intake pipe 40 via a negative pressure hose 58 (FIG. 4). An intake air temperature sensor 59 (FIG. 3) is provided in the air cleaner 25.

The intake pressure sensor 57 may be provided near the intake manifold. Further, a throttle position sensor (not shown) is provided on the valve shaft of the throttle valve on the side opposite to the link 55.
May be provided. In this case, the auto choke 56 is provided upstream of the throttle valve so as not to interfere with the throttle position sensor.

The front lower portion of the fuel tank 10 is fixed to the left and right body frame members 61 via brackets 60. A fuel hose 62 is pulled out from the rear of the fuel tank 10 and supplies fuel to the injector 50. The fuel hose 62 is fixed to the rear body frame member 34 via a stay 63 (FIGS. 2 and 4). 64 (FIG. 2) is an overflow pipe. Reference numeral 65 (FIG. 3) shows a battery, and 66 (FIG. 3) shows a recovery tank for cooling water. As shown in FIG. 3, a secondary air introduction system 86 for purifying exhaust gas is provided on the right side of the center of the vehicle body. This secondary air introduction system 8
6 communicates with the intake manifold via a negative pressure hose 87,
External air is supplied to a catalyst (not shown) via an air hose 88 according to negative intake pressure to reburn the exhaust gas.

A blow-by gas hose 90 is connected to the air cleaner 25, as shown in FIG. The blow-by gas hose 90 communicates with a cam chain chamber (not shown) that communicates with a crankcase (not shown) of the engine 29, and prevents oil seal dropout and loss horsepower due to pressure rise in the crankcase of the engine or the like. The blow-by gas hose 90 is connected to the clean side of the air cleaner after passing through the element, and the blow-by gas is introduced into the combustion chamber again.

FIG. 5 is a configuration diagram of the fuel tank according to the present invention. Fuel 107 is stored in the fuel tank 10.
Reference numeral 108 denotes a float type fuel gauge. Fuel tank 1
A fuel pump 109 is provided inside 0, and sucks the fuel 107 through the filter 110. The fuel pump 109 constitutes an in-tank type pump unit 112 together with the pressure regulator 111, and is fixed to the fuel tank 10 by a plurality of bolts 114 via a disc-shaped lid 113. A coupler 115 for electrical wiring is provided on the upper surface side of the lid 113. The rubber fuel hose 62 is fitted into the discharge port 116 of the pump unit 112. The fuel tank 10 has a stepped recess 117 having a reduced height on the rear side thereof. An insertion hole 213 is formed in this recess 117. Pump unit 1 with fuel pump 109 attached
The lower portion of 12 is inserted into the insertion hole 213 and is disposed in the fuel tank 10.

6 and 7 are a top view and a side view, respectively, of the fuel tank portion of the motorcycle of FIG.

As shown in FIG. 6, the left and right front portions of the fuel tank 10 are fixed to the vehicle body frame member 61 through the brackets 60, and the rear portions of the left and right rear vehicle bodies through the tank flange 118 and the bolts 119, respectively. It is fixed to the frame member 34. A recess 117 having a wide right side and a narrow left side is formed in the rear portion of the fuel tank 10.
An in-tank pump unit 112 is fixed to the right side portion of 17 with six bolts 114 via a cap 113. The coupler 115 on the upper surface of the cap 113 is connected to the engine control unit 47 (FIG. 3) via the cable 120. The fuel hose 62 passes through the left side portion (narrow portion) of the recess 117, bends downward, and
(See FIG. 7). The fuel hose 62 is held by a stay 63 fixed to the rear body frame member 34 (described later). A suction piston 51 and a battery 65 are arranged behind the fuel tank 10.

A fuel inlet 122 surrounded by a filler cover 121 is provided at the front of the fuel tank 10 and is closed by a cap 123. The breather hose 12 taken out from the upper portion of the fuel tank 10 has a rollover valve 124.
(See FIG. 7) through the canister 13. The canister 13 communicates with the throttle body 48 via the purge hose 14. The overflow pipe 64 is connected to the filler cover 121.

The fuel pipe system of the motorcycle of this embodiment is a returnless pipe. As shown in FIG. 7, only the fuel hose 62 is connected to the injector 50 and the return pipe is not connected. Therefore, the suction piston 48
The piping system can be efficiently arranged in a narrow space around the engine behind the fuel tank 10 that is narrowed by the battery 65 or the like. The fuel hose 62 is made of flexible rubber having a large flexibility.

The fuel hose 62 is preferably composed of a high pressure rubber molded hose. By molding the high-pressure rubber hose material, the layout of the fuel hose 62 can be determined according to a preset component arrangement, and the fuel hose 62 can be formed in the shape of the layout. As a result, when the fuel hose is provided, the initial load is not increased by hitting other parts, and external force is not applied or rubbed and deteriorated due to rocking. In addition, it prevents the looseness of the connection part due to the elasticity of the fuel hose and the occurrence of twisting etc. due to forcible mounting, and secures a clearance with other parts in the place where parts are convoluted in a narrow space and has a compact structure and reliability. High connections are achieved.

FIG. 8 is a side view of the entire vehicle body frame of the motorcycle shown in FIG. 1, and FIG. 9 is a top view of the essential parts thereof. The vehicle body frame 139 includes a central down tube 139 fixed to the head pipe 3 at the front of the vehicle body, and front vehicle body frame members 14 provided on both left and right sides of the down tube 139.
0 and the rear body frame member 34 that is continuous with the left and right front body frame members 140 via the elbow frame 145.
Composed of and. Left and right rear body frame members 34
A cross member 142 is provided between them. A battery bracket 143 is fixed in the middle of the cross member 142, and a battery 65 (see FIGS. 3 and 6) is mounted.
A damper bracket 144 is fixedly attached to the lower rear side of the rear body frame member 34 on the left side of the vehicle body.
A damper mounting hole 33a is provided in which an upper end 33 (see FIG. 2) of (see FIG. 2) is pivotally mounted.

A vehicle body frame member 61 is provided between the middle portion of the down tube 139 and the left and right rear vehicle body frame members 34 diagonally rearward thereof.
The bracket 60 is fixedly attached to 1. Left and right bracket 6
A support member 141 is provided by connecting the upper end portions of 0s.
The tank flange 118 (see FIGS. 6 and 7) at the front of the fuel tank is supported on the support member 141, and the bolt hole 1
It is fixed with two bolts 148 (FIG. 8) through 46. A stay 63 having a U-shaped cross section is fixed to each of the left and right rear body frame members 34. The left and right rear portions of the tank flange 118 are respectively supported on the left and right stays 63, and are fixed by bolts 119 (see FIGS. 6 and 7) through bolt holes 147.

A notch 118a is formed in the rear left corner of the tank flange 118. The fuel hose 62 is arranged through the notch 118a. As will be described later, the fuel hose 62 is clamped by the holder 150 (FIG. 11) and fixedly held by the stay 63 by the bolt 149.

FIG. 10 is a perspective view of the fuel tank 10. The fuel tank 10 has an upper and lower two-divided structure, and has a flange around each of the upper and lower divided bodies, and the tank flange 118 is formed by joining the flanges. The recess 117 is formed in the rear portion of the upper divided body (the portion above the tank flange 118) of the fuel tank 10 as described above. The pump unit 11 is provided on the right side of the recess 117.
2 is attached. The depth (height from the flange surface) of the recess 117 is determined so that the tops of the components such as the coupler 115 protruding on the upper surface of the pump unit 112 do not protrude from the upper surface of the fuel tank 10. The depth of this recess 117 is approximately the same as or slightly higher than the flange surface, depending on the height of the component.

The fuel hose 62 is inserted into the discharge port 116 of the pump unit 112 and fixed by the band 152.
The fuel hose 62 made of the high-pressure rubber molded as described above is disposed across the recess 117 and is disposed below the fuel tank through the notch 118a of the flange 118, and is attached to the injector 50 (see FIG. 7). Connected. The grommet 153 is attached to the fuel hose 62 adjacent to the cutout 118a, and is retained by the stay 63 (FIGS. 8 and 9) as described later. The fuel hose 62 from the grommet 153 to the pump unit 112 side becomes a fixed hose portion 62a rigidly fixed to the vehicle body frame 138 (FIG. 8) to which the fuel tank 10 is fixed. The fuel hose 62 below the grommet 153 becomes a swing hose portion 62b that swings together with the injector.

A recess 154 is formed on the left side of the fuel tank 10 near the center of the rear portion of the bottom surface thereof. The injector 50 (FIG. 7) and the water temperature sensor 46 (FIG. 3) are arranged in the recess 154 with a clearance due to rocking secured.
151 is a breather pipe to which the breather hose 12 is connected.

FIG. 11 is a detailed cross-sectional view of a fixed portion of the fuel hose 62 in the middle of the fuel hose 62 to the vehicle body frame. The grommet 153 is attached to the fuel hose 62 (see FIG. 10). From the periphery of this grommet 153 to the holder 150
Is mounted and fixed to the side surface on the inner side of the vehicle body of the stay 63 having a U-shaped cross section with a bolt 149. The stay 63 is joined to the rear body frame member 34 by welding with the opening edge of the U-shape facing downward. 155 is a projection nut fixed to the inner surface of the stay 63. These stay 6
3, bolt 149, holder 150, grommet 153
Further, the fuel hose 62 is fixedly held to the vehicle body frame 138 by the projection nut 155.

Instead of such a stay 63, a midway portion of the fuel hose may be fixed to the vehicle body frame via a band made of plastic or metal.

When the fuel hose is fixed to the vehicle body frame, it may be directly fixed to the vehicle body frame with a band or the like, or an attachment piece such as a stay or a bracket may be fixed to the vehicle body frame by welding or the like. Alternatively, the fuel hose may be fixed.

FIG. 12 is a graph showing the pressure inside the hose (the pressure change inside the hose due to the reaction of the injection pressure by the injector) when the material of the fuel hose in the returnless piping structure is rubber and when it is a conventional hard nylon resin. is there. a shows the case of nylon resin, and b shows the case of rubber.
As can be seen from the graph, in the case of the nylon resin, the next injection occurs before the vibration of the pressure inside the hose is greatly attenuated because the variation is large. On the other hand, in the case of rubber, the variation is small and the vibration is immediately attenuated to provide a stable pressure. Therefore, in the case of a rubber fuel hose, the fuel can be injected into the engine at a stable pressure, the effects of pressure variations and vibrations can be suppressed, and A / F variations can be reduced, so that exhaust gas performance, engine There is no variation in performance, and highly accurate fuel injection control is performed.

FIG. 13 is an external view of a fuel hose mounting structure portion of a fuel injection engine according to another embodiment of the present invention, and FIG. 14 is an enlarged view of a main part thereof. As shown,
An end of the fuel hose 62 is connected to a discharge port 116 of an in-tank type pump unit 112 provided in the fuel tank 10. The other end of the fuel hose 62 is connected to an injector 50 provided on the intake manifold 39. The hose bracket 210 is attached to the fuel hose 62 near the connection portion with the injector 50. This hose bracket 210
Is the two bolts 2 with the fuel hose 62 held.
It is fixed to two bosses 212 protruding from the intake manifold 39 by 11. As a result, the fuel hose 62 is fixedly held by the intake manifold 39 that forms the intake passage of the engine.

In this case, it is desirable that the intermediate portion of the fuel hose 62 be fixed to the vehicle body frame 34 via the stay 63 or by another method as shown in the above-described embodiment (FIG. 7).

In the above embodiment, the injector 50 is provided in the intake manifold 39 of the intake pipe 40. However, in the 4-cycle engine, it may be provided in the intake passage formed in the cylinder head, or in the 2-cycle engine. Alternatively, it may be provided in the crank chamber or the scavenging port.

[0060]

As described above, according to the present invention, when the fuel hose connected to the injector rocks with the engine, the fuel hose connected to the injector rocks along with the engine. Since the midway portion is fixed to the vehicle body frame, the fuel hose between this fixed portion and the fuel tank also provided in the vehicle body frame is held in a fixed state and does not swing. Therefore, the influence of the swing on the connection portion with the fuel tank is eliminated, the stress is not applied, and the reliability of the connection with the fuel tank is improved. At the same time, the fuel hose from the fixed part to the injector side is elastically deformed following the swing of the engine, so the stress due to the swing deformation is absorbed, and the stress on the connection part with the injector hardly acts, and Improves connection reliability.

In this case, if the fuel hose near the injector connection portion is fixed to the engine side such as the intake pipe near the injector, the connection portion of the fuel hose to the injector swings together with the engine and the injector. No stress acts on the connection portion due to the rocking, and the reliability of the connection with the injector is further enhanced.

If the fuel tank and the injector are connected by only one fuel hose,
By constructing a fuel piping system with a returnless structure that does not have return piping using a single fuel hose that supplies fuel from the fuel tank to the injector, the number of piping is reduced and the configuration is simplified, especially space constraints For swing unit type engines with large size, a simple piping layout can be obtained and assembly work can be facilitated.

Further, when the fuel pump and the pressure regulator are provided in the fuel tank, the fuel pump and the pressure regulator required for the fuel piping system are stored in the fuel tank, so that the space can be effectively used. This simplifies the configuration and component layout in a narrow space around the engine.

Further, a stepped recess is formed on the upper surface of the fuel tank, and a fuel pump is disposed in the fuel tank by inserting an insertion hole formed in the recess, while one of the fuel hoses is inserted. If the portion is arranged in the recessed portion, an insertion hole is formed in the stepped recessed portion on the upper surface of the fuel tank, and the fuel pump is arranged in the fuel tank through this insertion hole. At the same time, it can be easily taken in and out, and a compact structure can be obtained without accommodating components such as the coupler on the upper surface of the fuel pump in the recessed portion so as not to project to the upper surface or side surface of the fuel tank. At the same time, part of the fuel hose, for example, the connection end that connects to the coupler, is placed in the stepped recess, so the fuel hose can be pulled out to the side of the fuel tank with a simple layout without protruding to the upper surface of the fuel tank. be able to.

Further, if the fuel hose is made of rubber, by using a highly flexible rubber fuel hose, it is possible to swing the swing unit type engine which swings largely with respect to the body frame. Following this, the stress acting on the piping system is absorbed, the piping and other members are protected, and a smooth fuel supply operation is maintained.

In this case, in particular, if a molded hose made of rubber for high pressure that withstands high pressure is used, not only flexibility is obtained, but also by pre-molding the hose in accordance with the piping layout, it is possible to prevent The initial load on the connection portion due to the hose deformation is reduced, and the stress on the connection portion due to the rocking deformation is reduced. This further increases the reliability of the fuel hose connection.

[Brief description of drawings]

FIG. 1 is an external view of a small motorcycle according to the present invention.

FIG. 2 is a side view of a main part of the motorcycle shown in FIG.

FIG. 3 is a plan view of a main part of the motorcycle shown in FIG.

FIG. 4 is a configuration diagram of an engine portion of the motorcycle of FIG.

FIG. 5 is a configuration diagram of a fuel tank according to the present invention.

FIG. 6 is a top view of a fuel tank portion of the motorcycle shown in FIG.

7 is a side view of the fuel tank portion of FIG.

8 is an overall side view of a vehicle body frame of the motorcycle shown in FIG.

9 is a top view of a main part of the vehicle body frame of FIG.

FIG. 10 is a perspective view of the fuel tank of the present invention.

FIG. 11 is a cross-sectional view of a fuel hose attachment portion of the present invention.

FIG. 12 is a graph of pressure change in the fuel hose.

FIG. 13 is an external view of a fuel hose mounting structure portion of a fuel injection engine according to another embodiment of the present invention.

FIG. 14 is an enlarged view of a main part of the embodiment of FIG.

[Explanation of symbols]

1: vehicle body, 2: steering wheel, 3: head pipe, 4: steering shaft, 5: front wheel, 6: vehicle body frame, 7: cowling, 8: vehicle body cover, 9: seat, 10: fuel tank, 11: helmet box, 12: breather hose, 13: canister, 14: purge hose, 15: throttle wire, 16: brake cable, 17: rear wheel, 18: brake cam shaft, 19: engine unit, 20: engine bracket, 21: lower body frame member , 22: pivot, 23: damper, 24: reducer, 25: air cleaner 1, 25a: air intake opening, 26: dust cover, 27: stand, 28: kick lever, 29: engine, 30: duct, 30a. : Open end, 31: shaft, 32: link plate, 33: upper end,
33a: damper mounting hole, 34: rear body frame member, 35: lower end, 36: bracket, 37: cylinder,
38: crankshaft, 39: intake manifold, 40: intake pipe, 41: exhaust pipe, 42: heat insulating material, 43: flange, 4
4: Bolt, 45: Cover for maintenance, 46: Water temperature sensor,
47: engine control unit, 48: throttle body, 49: joint, 49a: joint end, 5
0: injector, 51: suction piston, 52:
Diaphragm chamber, 53: Atmosphere passage, 54: Atmosphere intake,
55: link, 56: auto choke, 57: intake pressure sensor, 58: negative pressure hose, 59: intake temperature sensor, 60:
Bracket, 61: vehicle body frame member, 62: fuel hose, 62a: fixed hose portion, 62b: swing hose portion, 6
3: stay, 64: overflow pipe, 65: battery, 66: recovery tank, 72: wire harness, 74: throttle valve, 78: rubber joint,
78a: concave portion, 79: piston, 80: diaphragm,
81: first chamber, 82: second chamber, 83: negative pressure port, 8
4: Spring, 86: Secondary air introduction system, 87:
Negative pressure hose, 88: Air hose, 89: Water temperature signal cable, 90: Blow-by gas hose, 107: Fuel, 10
8: Float type fuel gauge, 109: Fuel pump, 11
0: filter, 111: pressure regulator, 112: pump unit, 113: lid, 114: bolt, 115:
Coupler, 116: Discharge port, 117: Dimple, 118: Tank flange, 118a: Notch, 119: Bolt, 1
20: Cable, 121: Filler cover, 122: Fuel inlet, 123: Cap, 124: Rollover valve, 138: Body frame, 139: Down tube, 140: Front body frame member, 141: Support member, 142: Cross member, 143: battery bracket, 144: damper bracket, 145: elbow frame, 146: bolt, 147: bolt hole, 148,
149: Bolt, 150: Holder, 151: Breather pipe, 152: Band, 153: Grommet, 15
4: recessed portion, 155: projection nut, 210:
Hose bracket, 211: Bolt, 212: Boss, 2
13: Insertion hole.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tsuyoshi Sugitani             Yamaha Motor, 2500 Shinkai, Iwata, Shizuoka Prefecture             Within the corporation

Claims (5)

[Claims] 1. A fuel injection engine equipped with an injector is integrated with a reducer connected to a rear wheel to form an engine unit, and the engine unit is pivotally attached to a vehicle body frame so that the engine unit is attached to the rear wheel. In a fuel hose mounting structure for a motorcycle, wherein the fuel hose is pivotally attached to a vehicle body, a fuel tank is provided on the vehicle body frame, and the fuel tank and the injector are connected by a fuel hose. A fuel hose for a motorcycle, characterized in that the fuel hose between the injector and the fixing part of the fuel hose to the vehicle body frame is elastically deformable in accordance with the rocking motion of the engine unit. Mounting structure. 2. The fuel hose mounting structure for a motorcycle according to claim 1, wherein the fuel tank and the injector are connected by only one fuel hose. 3. A fuel pump and a pressure regulator are provided in the fuel tank.
The fuel hose mounting structure for the motorcycle described in. 4. A stepped recess is formed on an upper surface of the fuel tank, and a fuel pump is disposed in the fuel tank by inserting an insertion hole formed in the recess, while one of the fuel hoses is provided. The fuel hose mounting structure for a motorcycle according to any one of claims 1 to 3, wherein a portion is disposed in the recessed portion. 5. The fuel hose mounting structure for a motorcycle according to claim 1, wherein the fuel hose is made of rubber.