JP4690364B2 - Fuel hose mounting structure for motorcycle fuel injection engines - Google Patents

Description

  The present invention relates to a fuel hose mounting structure of a swing unit type fuel injection engine for a motorcycle.

  In a small motorcycle such as a scooter, a swing unit type engine is used. This swing unit type engine forms an engine unit by integrally connecting an engine crankcase and a speed reducer case, and connects a rear wheel to the speed reducer and swingably attaches to a vehicle body frame via a damper. The front part is pivotally attached to the vehicle body frame via a pivot. As a result, the engine unit can rotate within the angular range centered on the pivot together with the rear wheel, and swings with respect to the vehicle body frame to absorb vibration during traveling.

  Such a swing unit type engine is described in Patent Document 1, for example.

  As a swing unit type engine of such a small motorcycle, a two-cycle engine or a four-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 constituting 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 four-cycle engine, an injector is provided facing an intake passage on the downstream side of the throttle body, and fuel is injected. The intake air that has been injected with fuel to become an air-fuel mixture passes through the intake manifold and is sucked into the engine combustion chamber via 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 made high by a fuel pump and supplied to the injector through a 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. The 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 is conventionally used for a fuel injection engine of a four-wheeled vehicle.

The fuel injected from the injector is sent from the fuel tank fixed to the vehicle body frame to the injector through the fuel hose by the fuel pump 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 a vehicle body frame and peripheral parts around the engine. Therefore, the elastic force accompanying the elastic deformation of the fuel hose acts as an initial load on the connecting portion of the fuel hose.
JP 2001-48081 A

  However, in a small scooter or the like, the space around the engine is narrow, and in order to reduce the size and weight, it is not possible to increase the strength by increasing the size of the connection portion. For this reason, the elastic force of the initial load of the fuel hose may cause the connection reliability to gradually decrease with long-term use. In particular, in a swing unit type fuel injection engine, since the injector swings together with the engine, the fuel hose connected to the injector also swings. Act on the part. For this reason, the risk of a decrease in connection reliability is further increased.

  In addition, 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 a large restriction on the fuel piping layout, and the engine itself swings with respect to the vehicle body (small scooter). The conventional fuel pipe structure of a four-wheeled vehicle cannot be used as it is.

  The present invention takes the above-described prior art into consideration, and an object thereof is to provide a fuel hose mounting structure in which the reliability of the connecting portion of the fuel hose is improved in a swing unit type fuel injection engine.

  When the present invention is applied to a motorcycle equipped with a fuel injection engine of a swing unit type in which space constraints are particularly large, a fuel piping structure capable of coping with engine swing can be obtained with a simple configuration.

In order to achieve this object, the fuel hose mounting structure for a motorcycle fuel injection engine according to the present invention integrates a fuel injection engine equipped with an injector together with a speed reducer connected to a rear wheel to form an engine unit. The engine unit is pivotally attached to the vehicle body frame, the engine unit is pivotally attached to the vehicle body together with the rear wheel, a fuel tank is fixed to the vehicle body frame, and a fuel between the fuel tank and the injector A fuel hose mounting structure for a motorcycle provided with a fuel hose that can be elastically deformed in a piping system, wherein a middle part of the fuel hose is fixed to a vehicle body frame, and the fixing part of the fuel hose to the vehicle body frame, the injector the fuel hose is bent in a U-shape that opens upward between the formed, put in a longitudinal direction of the fuel hose of the bent portion The part on the engine unit side is fixed to the engine unit via a hose bracket mounted on the upstream side of the fuel hose connected to the injector, and the fuel hose fixing part to the vehicle body frame and the engine The fixed portions to the unit are separated from each other in the vehicle width direction .

  According to the present invention, in the above invention, the fixing portion of the fuel hose to the vehicle body frame is positioned so as to be adjacent to the edge of the fuel tank.

  According to the present invention, in the above invention, a fuel pump is provided in the fuel tank so that a discharge port protrudes upward, and one end of the fuel hose is fitted into the discharge port of the fuel pump, The part between the fitting part to the discharge port of the fuel pump and the fixing part to the vehicle body frame is disposed along the upper surface of the fuel tank and constitutes a fixing hose part.

  According to the present invention, when the fuel hose connected to the injector swings as the injector provided in the engine swings together with the engine, the middle part of the swinging fuel hose is fixed to the vehicle body frame. Therefore, the fuel hose between the fixed portion and the fuel tank provided in the vehicle body frame is held in a fixed state and does not swing. Therefore, the influence on the connecting portion with the fuel tank due to the swinging is eliminated and the stress does not act, and the reliability of the connection with the fuel tank is increased. At the same time, the fuel hose on the injector side from the fixed portion is elastically deformed following the engine swing, so that the stress due to the swing deformation is absorbed and the stress on the connection portion with the injector hardly acts. Increased connection reliability.

  According to the invention in which the end portion of the bent portion on the engine unit side is fixed to the engine unit by the hose bracket, the connecting portion of the fuel hose to the injector swings together with the engine and the injector, so that stress on the connecting portion due to swinging is exerted. There is no effect, and the reliability of the connection with the injector is further increased.

  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 a front wheel 5 via a steering shaft 4 through which a head pipe 3 is inserted. A body frame 6 is coupled to the head pipe 3. The 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 is covered with a vehicle body cover 8 from the outside of the vehicle body frame 6. A seat 9 is provided at the center of the vehicle body, a fuel tank 10 is provided on the lower side, and a helmet box (case) 11 is provided on the rear side. The fuel tank 10 supplies fuel to an injector (not shown) via a fuel hose (not shown). One end of the breather hose 12 is connected to the upper portion of the fuel tank 10, 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) of the handle portion and is connected to a brake cam shaft 18 of the rear wheel 17.

  An engine unit 19 is attached to the vehicle body frame 6 at the center of the vehicle body. The engine unit 19 includes an engine (not shown) and a speed reducer 24 integrally coupled to a crankcase (not shown). The engine unit 19 is suspended via an engine bracket 20 so as to be rotatable around a pivot 22 with respect to a lower body frame member 21 constituting a part of the body frame 6. The rear wheel 17 is connected to the rear portion of the engine unit 19 and the lower end of the damper 23 is pivoted. The upper end of the damper 23 is pivotally attached to a rear body frame (not shown) constituting a part of the body frame 6. As a result, the engine unit 19 can swing around the pivot 22 together with the rear wheel 17 to form a swing unit type engine.

  An air cleaner 25 is provided above the speed reducer 24. An outside air intake opening 25 a is opened at the front of the air cleaner 25, and a dustproof cover 26 made of rubber or resin is provided inside the vehicle body cover 8 so as to cover the opening. Reference numeral 27 denotes a stand, and 28 denotes a kick lever.

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

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

  An engine bracket 20 is integrally coupled to a front portion of the engine unit 19 of the swing unit engine type. A link plate 32 is pivotally attached to the engine bracket 20 via a shaft 31. The link plate 32 is rotatably attached to the lower body frame member 21 via the pivot 22.

  A damper (shock absorber) 23 is provided at the rear of the engine unit 19. The upper end 33 of the damper 23 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 portion of the engine unit 19. As a result, the engine unit 19 is mounted so as to be swingable with respect to the vehicle body frame around the pivot 22 on the front side. As shown in FIG. 4, the cylinder 37 of the engine 29 is tilted forward almost to the horizontal. The crankshaft 38 swings as shown by the arrow D together with the shaft 31 of the engine bracket 20 (FIG. 2) around the pivot 22 described above.

  The intake side of the engine 29 is provided with an intake manifold 39 communicating with an intake port (not shown) of the cylinder head and an intake pipe 40 (FIGS. 3 and 4) connected thereto, and an exhaust pipe 41 (FIG. 3) is provided on the exhaust side. ) Is connected. The intake pipe 40 is a bent elbow-like intake pipe. As shown in FIG. 4, the flange 43 is abutted against each other via a resin heat insulating material 42 and is fixed by two bolts 44. Reference numeral 45 denotes a valve cam maintenance cover. 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 sent to the engine control unit 47 (FIG. 3) via the water temperature signal cable 89 (FIG. 3) and the wire harness 72. Further, a detection signal cable (not shown) of an intake air temperature sensor and an intake pressure sensor, which will be described later, is connected to the engine control unit 47 via a wire harness 72, and the 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 bent elbow-shaped intake pipe 40 described above. The throttle body 48 is connected to the air cleaner 25 via a joint 49. An 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 on the upstream side thereof. As will be described later, the suction piston 51 has a diaphragm chamber 52 provided on the upper side of the throttle body 48, and an air inlet (atmosphere open end) 54 of an air passage 53 for introducing the air into the diaphragm chamber 52 is a throttle. Provided on the lower side of the body 48. A throttle wire 15 connected to a throttle lever (not shown) or a throttle grip 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 is covered with a dustproof cover 26 (a chain line in FIG. 1) made of rubber or resin. A vehicle body cover is further attached to the outside of the dust cover 26. The air intake 54 of the suction piston 51 opens inside the dust cover 26.

  Adjacent to the suction piston 51, the throttle body 48 is provided with a heater-type wax type auto choke 56 and an intake pressure sensor 57 (FIG. 3). The auto choke 56 opens and closes a bypass pipe (not shown) that communicates 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 in the vicinity of the intake manifold. Further, a throttle position sensor (not shown) may be provided on the valve shaft of the throttle valve opposite to the link 55. 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 vehicle body frame members 61 via the bracket 60. A fuel hose 62 is pulled out from the rear of the fuel tank 10 to supply 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. 65 (FIG. 3) is a battery, and 66 (FIG. 3) is a cooling water recovery tank. 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. The secondary air introduction system 86 communicates with the intake manifold via a negative pressure hose 87, and supplies outside air to a catalyst (not shown) via an air hose 88 in accordance with the intake negative pressure to reburn the exhaust gas.

  As shown in FIG. 2, a blow-by gas hose 90 is connected to the air cleaner 25. The blow-by gas hose 90 communicates with a cam chain chamber (not shown) that leads to a crankcase (not shown) of the engine 29, and prevents oil seal drop and loss horsepower due to a pressure increase in the crankcase of the engine. This blow-by gas hose 90 is connected to the clean side after passing through the element in the air cleaner, and the blow-by gas is again introduced into the combustion chamber.

  FIG. 5 is a configuration diagram of a fuel tank according to the present invention. Fuel 107 is accommodated in the fuel tank 10. Reference numeral 108 denotes a float type fuel gauge. A fuel pump 109 is provided in the fuel tank 10 and sucks up 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 through a disk-shaped lid 113. A coupler 115 for electrical wiring is provided on the upper surface side of the lid 113. A rubber fuel hose 62 is fitted into the discharge port 116 of the pump unit 112. The fuel tank 10 is formed with a stepped recess 117 having a reduced height on the rear side. An insertion hole 213 is formed in the recess 117. The lower portion of the pump unit 112 to which the fuel pump 109 is attached is inserted into the fuel tank 10 through the insertion hole 213.

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

  As shown in FIG. 6, the left and right of the front portion of the fuel tank 10 are fixed to the vehicle body frame member 61 via the bracket 60, and the rear portion is fixed to the left and right rear vehicle body frame members 34 by bolts 119 via the tank flange 118. Fixed to. A recess 117 is formed in the rear portion of the fuel tank 10 and has a narrow right side. The in-tank pump unit 112 is fixed to the right portion of the recess 117 with six bolts 114 through 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 is bent downward through the left portion (narrow portion) of the recess 117 and connected to the injector 50 (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 disposed 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 with a cap 123. The breather hose 12 taken out from the upper part of the fuel tank 10 communicates with the canister 13 via a rollover valve 124 (see FIG. 7). The canister 13 communicates with the throttle body 48 via the purge hose 14. An overflow pipe 64 is connected to the filler cover 121.

  The fuel piping system of the motorcycle of this embodiment is a returnless piping. As shown in FIG. 7, only the fuel hose 62 is connected to the injector 50, and the return piping is not connected. Therefore, the piping system can be efficiently arranged in a narrow space around the engine behind the fuel tank 10 narrowed by the suction piston 51, the battery 65, and the like. The fuel hose 62 is made of a soft rubber having a high flexibility.

  The fuel hose 62 is preferably composed of a molded hose made of high-pressure rubber. By molding the high-pressure rubber hose material, the layout of the fuel hose 62 can be determined in accordance with 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 disposed, the initial load is not increased by hitting other components, and external force is not applied or rubbed and deteriorated with the swing. In addition, the looseness of the connecting part due to the elasticity of the fuel hose and the occurrence of twisting due to unreasonable mounting are suppressed, and clearance with other parts is secured in a place where the parts are confined in a narrow space, and a compact configuration ensures reliability. High connection is achieved.

  FIG. 8 is a side view of the entire body frame of the motorcycle shown in FIG. 1, and FIG. 9 is a top view of the main part thereof. The vehicle body frame 138 includes a central down tube 139 fixed to the head pipe 3 at the front of the vehicle body, a front vehicle body frame member 140 provided on both the left and right sides of the down tube 139, and a left and right front vehicle body frame member 140. The rear body frame member 34 is continuous with the elbow frame 145. A cross member 142 is provided between the left and right rear body frame members 34. 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 fixed to a rear lower side of the rear body frame member 34 on the left side of the vehicle body, and a damper mounting hole 33a is provided to which an upper end 33 (see FIG. 2) of the damper 23 (see FIG. 2) is pivotally attached.

  A vehicle body frame member 61 is provided between the intermediate portion of the down tube 139 and the left and right rear vehicle body frame members 34 obliquely behind the down tube 139, and the bracket 60 is fixed to the vehicle body frame member 61. A support member 141 is provided by connecting the upper end portions of the left and right brackets 60. A tank flange 118 (see FIGS. 6 and 7) at the front of the fuel tank is supported on the support member 141, and is fixed by two bolts 148 (FIG. 8) through the bolt holes 146. The left and right rear body frame members 34 are each fixed with a stay 63 having a U-shaped cross section. 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 the bolt holes 147.

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

  FIG. 10 is a perspective view of the fuel tank 10. The fuel tank 10 has an upper and lower divided structure, and has a flange around each of the upper and lower divided bodies, and the flanges are joined together to form a tank flange 118. As described above, the recess 117 is formed in the rear portion of the upper divided body of the fuel tank 10 (the portion above the tank flange 118). The pump unit 112 is attached to the right side portion of the recess 117. 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 the dent 117 is approximately the same as or slightly higher than the flange surface, depending on the height of the part.

  The fuel hose 62 is inserted into the discharge port 116 of the pump unit 112 and fixed with a band 152. The fuel hose 62 made of high-pressure rubber molded as described above is disposed across the recess 117, and is disposed in the lower portion of the fuel tank through the notch 118a of the flange 118. The fuel hose 62 is disposed in the injector 50 (see FIG. 7). Connected. A grommet 153 is attached to the fuel hose 62 adjacent to the notch 118a and held by the stay 63 (FIGS. 8 and 9) as will be described later. That is, the fixing portion of the fuel hose 62 to the vehicle body frame 6 is positioned adjacent to the edge of the fuel tank 10.

The fuel hose 62 on the pump unit 112 side from the grommet 153 becomes a fixed hose portion 62a fixed rigidly to the vehicle body frame 138 (FIG. 8) to which the fuel tank 10 is fixed. More specifically, a fuel pump 109 is provided in the fuel tank 10 so that the discharge port 116 protrudes upward, and one end of the fuel hose 62 is fitted into the discharge port 116 of the fuel pump 109. 62 is disposed along the upper surface of the fuel tank 10 between the fitting portion of the fuel pump 109 into the outlet 116 of the fuel pump 109 and the fixing portion to the vehicle body frame 6 to form a fixing hose portion 62a. ing.
A U-shaped bent portion that opens upward is formed on the lower side of the fuel hose 62 from the grommet 153 as shown in FIGS. 2, 4, and 7. One end of the bent portion is fixed to the rear vehicle body frame member 34 via the holder 150 and the stay 63, and the other end is fixed to the engine unit 19 via the injector 50. This bent portion of the fuel hose 62 becomes a swing hose portion 62b that swings together with the injector.
As shown in FIGS. 3 and 6, the fixing portion of the fuel hose 62 to the vehicle body frame 6 and the connecting portion to the injector 50 (fixing portion to the engine unit) are separated from each other in the vehicle width direction. become.

  A recess 154 is formed in the left side portion from the vicinity of the rear center of the bottom surface of the fuel tank 10. In the recess 154, the injector 50 (FIG. 7) and the water temperature sensor 46 (FIG. 3) are arranged with a clearance by swinging. 151 is a breather pipe to which the breather hose 12 is connected.

  FIG. 11 is a detailed cross-sectional view of the fixing portion for the vehicle body frame in the middle of the fuel hose 62. A grommet 153 is attached to the fuel hose 62 (see FIG. 10). A holder 150 is mounted from the periphery of the grommet 153 and is fixed to the side surface of the vehicle body inside 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 U-shaped opening edge down. Reference numeral 155 denotes a projection nut fixed to the inner surface of the stay 63. The fuel hose 62 is fixedly held on the vehicle body frame 138 by the stay 63, the bolt 149, the holder 150, the grommet 153, and the projection nut 155.

  Instead of the stay 63, the middle part of the fuel hose may be fixed to the vehicle body frame via a plastic or metal band.

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

  FIG. 12 is a graph showing the pressure in the hose (change in pressure in 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 the conventional hard nylon resin. 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 nylon resin, the next injection occurs before the vibration of the pressure inside the hose is attenuated and the variation is large. On the other hand, in the case of rubber, there is little variation and vibrations are immediately damped and a stable pressure is obtained. Therefore, in the case of a rubber fuel hose, it is possible to inject fuel at a stable pressure to the engine and to suppress the influence of pressure variation and vibration, and to reduce the A / F variation, thereby reducing 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, the end of the fuel hose 62 is connected to the discharge port 116 of the in-tank pump unit 112 provided in the fuel tank 10. The other end of the fuel hose 62 is connected to an injector 50 provided in the intake manifold 39. A hose bracket 210 is attached to the fuel hose 62 in the vicinity of the connecting portion with the injector 50. The hose bracket 210 is fixed to the two bosses 212 protruding from the intake manifold 39 by the two bolts 211 while holding the fuel hose 62. As a result, the fuel hose 62 is fixedly held by the intake manifold 39 constituting the intake passage of the engine. That is, the portion on the engine unit side in the longitudinal direction of the fuel hose 62 between the injector 50 and the pump unit 112 is connected via the hose bracket 210 mounted on the upstream side of the connecting portion with the injector 50 in the fuel hose 62. It is fixed to the engine unit.

  In this case, it is desirable to fix the intermediate portion of the fuel hose 62 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 case of a 4-cycle engine, it may be provided in the intake passage formed in the cylinder head. You may provide in a chamber or a scavenging port.

  As described above, according to the present invention, when the fuel hose connected to the injector swings as the injector provided in the engine swings together with the engine, the middle portion of the swinging fuel hose is the body frame. Therefore, the fuel hose between the fixing portion and the fuel tank similarly provided on the vehicle body frame is held in a fixed state and does not swing. Therefore, the influence on the connecting portion with the fuel tank due to the swinging is eliminated and the stress does not act, and the reliability of the connection with the fuel tank is increased. At the same time, the fuel hose on the injector side from the fixed portion is elastically deformed following the engine swing, so that the stress due to the swing deformation is absorbed and the stress on the connection portion with the injector hardly acts. Increased connection reliability.

  In this case, if the fuel hose in the vicinity of the injector connecting portion is fixed to the engine side such as the intake pipe in the vicinity of the injector, the connecting portion of the fuel hose to the injector swings together with the engine and the injector. The stress on the connection portion does not act, and the reliability of the connection with the injector is further increased.

  Further, if the fuel tank and the injector are connected by only one fuel hose, a returnless structure without a return pipe using a single fuel hose that supplies fuel from the fuel tank to the injector. By configuring this fuel piping system, the number of piping is reduced and the configuration is simplified. In particular, a simple piping layout is obtained in a swing unit type engine with a large space restriction, and assembly work can be facilitated.

  Further, if the fuel pump and the pressure regulator are provided in the fuel tank, the fuel pump and the pressure regulator necessary for the fuel piping system are accommodated in the fuel tank, so that the space is effectively used, and the engine Simplifies the configuration and component layout in the surrounding narrow space.

  Further, a step-shaped depression is formed on the upper surface of the fuel tank, and a fuel pump is disposed in the fuel tank through the insertion hole formed in the depression, while a part of the fuel hose is disposed in the fuel tank. If the configuration is arranged in the depression, an insertion hole is formed in the stepped depression on the upper surface of the fuel tank, and the fuel pump is arranged in the fuel tank through this insertion hole. Thus, a compact configuration can be obtained without storing the parts such as the coupler on the upper surface of the fuel pump in the recess so as not to protrude from the upper surface or the side surface of the fuel tank. At the same time, a part of the fuel hose, for example, a connecting end connected to the coupler is disposed in the step-shaped depression, so that the fuel hose is pulled out to the side of the fuel tank with a simple layout without protruding from the upper surface of the fuel tank. be able to.

  Furthermore, if the fuel hose is made of rubber, the rubber hose made of rubber having high flexibility can be used to follow the swinging motion of the swing unit engine that swings greatly with respect to the vehicle body frame. 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 it is a molded hose made of high-pressure rubber that can withstand high pressure, not only flexibility can be obtained, but also by pre-molding along the piping layout, due to hose deformation at the time of fuel hose installation The initial load on the connecting portion is reduced, and the stress on the connecting portion due to the rocking deformation is reduced. Thereby, the reliability of connection of a fuel hose connection part further increases.

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. 1. Fig. 2 is a plan view of a main part of the motorcycle shown in Fig. 1. FIG. 2 is a configuration diagram of an engine part of the motorcycle of FIG. 1. The block diagram of the fuel tank which concerns on this invention. Fig. 2 is a top view of a fuel tank portion of the motorcycle shown in Fig. 1. The side view of the fuel tank part of FIG. FIG. 2 is an overall side view of the body frame of the motorcycle shown in FIG. 1. The principal part top view of the vehicle body frame of FIG. The perspective view of the fuel tank of this invention. Sectional drawing of the fuel hose attachment part of this invention. Graph of pressure change in fuel hose. The external view of the fuel hose attachment structure part of the fuel-injection engine which concerns on another Example of this invention. The principal part enlarged view of the Example of FIG.

Explanation of symbols

  1: body, 2: handle, 3: head pipe, 4: steering shaft, 5: front wheel, 6: body frame, 7: cowling, 8: 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 camshaft, 19: Engine unit, 20: Engine bracket, 21: Lower body frame member , 22: pivot, 23: damper, 24: speed reducer, 25: air cleaner l, 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, 4: 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, 44: Bolt, 45: Maintenance cover, 46: Water temperature sensor, 47: Engine control unit, 48: Throttle body, 49: Joint, 49a: Joint end, 50: Injector, 51: Suction piston, 52: Diaphragm chamber, 53: Air passage, 54: Air intake, 55: Link, 56: Auto choke, 57: Intake pressure sensor, 58: Negative pressure hose, 59: Intake temperature sensor, 60: Bracket, 61: Body frame member, 62: Fuel hose 62a: fixed hose part, 62b: swinging hose part, 63: stay, 64: overflow pipe, 65: Battery 66: Recovery tank 72: Wire harness 74: Throttle valve 78: Rubber joint 78a: Recessed part 79: Piston 80: Diaphragm 81: First chamber 82: Second chamber 83: Negative pressure Port, 84: 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, 108: Float type fuel gauge, 109: Fuel pump 110: Filter, 111: Pressure regulator, 112: Pump unit, 113: Lid, 114: Bolt, 115: Coupler, 116: Discharge port, 117: Recessed part, 118: Tank flange, 118a: Notch, 119: Bolt , 120: 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, 154: recess, 155: projection nut, 210: hose bracket, 211: bolt 212: boss, 213: insertion hole.

Claims (3)

A fuel injection engine having an injector is integrated with a reduction gear connected to a rear wheel to form an engine unit. The engine unit is pivotally attached to a vehicle body frame, and the engine unit is pivoted to the vehicle body with a rear wheel. A fuel hose mounting structure for a motorcycle comprising a fuel hose that is movably mounted, a fuel tank is fixed to a vehicle body frame, and a fuel hose that is elastically deformable in a fuel piping system between the fuel tank and the injector,
A middle part of the fuel hose is fixed to a vehicle body frame, and a fuel hose between the fuel hose fixing part to the vehicle body frame and the injector is bent in a U shape to open upward ,
The engine unit side portion of the bent portion in the longitudinal direction of the fuel hose is fixed to the engine unit via a hose bracket mounted on the upstream side of the fuel hose connection portion with the injector,
A fuel hose mounting structure for a motorcycle, wherein a fixing portion of the fuel hose to the vehicle body frame and a fixing portion to the engine unit are separated from each other in the vehicle width direction .   The fuel hose mounting structure for a motorcycle according to claim 1, wherein the fixing portion of the fuel hose to the vehicle body frame is positioned adjacent to the edge of the fuel tank. Engine fuel hose mounting structure. The fuel hose mounting structure for a motorcycle according to claim 2 , wherein a fuel pump is provided in the fuel tank so that a discharge port protrudes upward,
One end of the fuel hose is fitted into the discharge port of the fuel pump,
A portion of the fuel hose between the fitting portion to the discharge port of the fuel pump and the fixing portion to the vehicle body frame is disposed along the upper surface of the fuel tank to constitute a fixing hose portion. A fuel hose mounting structure for a motorcycle fuel injection engine characterized by

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