JP5039672B2 - Fuel injection structure and vehicle including the same - Google Patents

Description

  The present invention relates to a fuel injection structure for injecting fuel supplied to an engine and a vehicle such as a motorcycle including the same.

  An engine mounted on a vehicle is connected to a throttle body having a throttle valve, and an intake duct, an air cleaner, and the like are sequentially connected to the throttle body. An intake passage to the engine is formed by the internal spaces of these parts (see, for example, Patent Document 1).

As shown in Patent Document 1, a so-called double injector system is known as a high-power engine. According to this method, two injectors are provided separately on the upstream side and the downstream side of the throttle valve in the intake passage. The upstream injector may be provided, for example, in an air cleaner on the upstream side with respect to the intake duct, and is configured to inject fuel mainly at high rotation and high output.
JP 2006-90289 A

  In the intake passage, an air flow from the air cleaner side to the engine side is not always generated, but air is blown back from the engine side to the air cleaner side according to the operation of the piston. At the time of high rotation and high output, due to this injection back, it is difficult to introduce all of the fuel injected from the upstream injector into the intake duct. Thus, if the fuel returned to the air cleaner box is stored in the air cleaner box, it becomes difficult to control the air-fuel ratio when the engine is operating, which may affect the output performance and exhaust gas performance.

  Therefore, the present invention makes it easy to introduce fuel injected by an injector provided on the upstream side of the intake duct into the intake duct, thereby reducing the amount of fuel sprayed back, thereby reducing the decrease in engine output performance. The purpose is to do.

In view of such circumstances, a fuel injection structure according to the present invention includes an injector that injects fuel toward an upstream end opening of an intake duct that forms part of an intake passage to the engine, and the intake passage that is provided in the intake passage. A fuel guide portion surrounding a fuel injection portion of the injector, the fuel guide portion extends toward an upstream end opening of the intake duct, and the air cleaner box has an injector attachment portion for attaching the injector, The fuel guide portion integrally protrudes from the injector mounting portion of the air cleaner box and extends toward the upstream opening of the intake duct, and the injector is connected to the injector mounting portion from the outside of the air cleaner box. A delivery pipe that is attached and distributes fuel to the injector is provided in the air cleaner box. It is characterized in that it is arranged outside the scan.

With such a configuration, the fuel from the injector provided on the upstream side with respect to the intake duct is guided by the fuel guide portion toward the upstream end opening of the intake duct. For this reason, even if air is blown back, all of the fuel injected from this injector can be easily introduced into the intake duct, so that the fuel can be used properly, and the reduction in engine output performance is reduced. Can do. In addition, a dedicated part for providing the fuel guide portion can be omitted, and the structure can be simplified.

The front end portion of the fuel guide portion may be disposed in the intake duct. With such a configuration, it becomes easier to introduce the fuel injected from the injector into the intake duct. The engine has a plurality of cylinders, the intake duct and the injector are provided for each cylinder, and the tip of the fuel guide part is arranged in the intake duct for some cylinders, and the remaining cylinders The tip of the fuel guide may be located upstream of the upstream end opening of the intake duct. The fuel guide portion may have an inner circumferential surface that increases in diameter and a thickness that decreases toward the tip.

The fuel injection structure according to the present invention includes an injector that injects fuel toward an upstream end opening of an intake duct that forms a part of an intake passage to the engine, and a fuel provided in the intake passage and disposed in the intake passage. and a fuel guide portion surrounding the injector, extends the fuel guide portion toward the upstream end opening of the intake duct, the fuel guide portion is Ru swingable with a fulcrum proximal portion. By adopting such a configuration, a structure in which the posture of the tip portion of the fuel guide portion with respect to the intake duct is variable and the fuel injection direction can be changed is realized.

  At this time, a swing actuator that swings the fuel guide and a swing control unit that swings the fuel guide by operating the swing actuator according to an operating state of the engine may be provided. Good. With such a configuration, the fuel injection direction can be appropriately changed according to the operating state of the engine.

The fuel injection structure according to the present invention includes an injector that injects fuel toward an upstream end opening of an intake duct that forms a part of an intake passage to the engine, and a fuel provided in the intake passage and disposed in the intake passage. and a fuel guide portion surrounding the injector, the fuel guide portion extends toward the upstream end opening of the intake duct, the fuel guide portion is Ru stretchable der. With this configuration, the distance from the fuel injection part to the tip of the fuel guide part can be varied, and a structure that can adjust the amount of air sent to the engine by changing the flow path resistance of the intake passage is realized. Is done.

  At this time, an expansion / contraction actuator that expands / contracts the fuel guide portion and an expansion / contraction control portion that expands / contracts the fuel guide portion by operating the expansion / contraction actuator according to an operating state of the engine may be provided. With such a configuration, the flow passage resistance of the intake passage can be appropriately changed according to the operating state of the engine.

  In addition, a vehicle according to the present invention includes the fuel injection structure described above, and a vehicle with high fuel consumption and high output can be provided by using all of the injected fuel. .

  As described above, according to the present invention, the fuel injected from the injector provided on the upstream side of the intake duct can be easily introduced into the intake duct to reduce the amount of fuel sprayed back. A decrease in output performance can be reduced.

  Embodiments according to the present invention will be described below with reference to the accompanying drawings. Here, a motorcycle is illustrated as a vehicle according to the present invention, and the direction related to the fuel injection structure according to the present invention is described with reference to the direction viewed by the rider of the motorcycle.

(First embodiment)
[Motorcycle]
FIG. 1 is a left side view of a motorcycle 1 having a fuel injection structure according to a first embodiment of the present invention. In the motorcycle 1 shown in FIG. 1, a front fork 3 is rotatably supported at a front end portion of a main frame 2, and a front wheel 4 is supported at a lower end portion of the front fork 3. A swing arm 5 is pivotally supported at the rear lower part of the main frame 2 so as to be swingable up and down, and a rear wheel 6 is supported on the swing arm 5.

  An engine 7 is attached to the lower center of the main frame 2. The rotational output of the engine 7 drives the rear wheel 6 through a chain (not shown), and thereby a forward driving force is applied to the motorcycle 1. A fuel tank 8 for storing liquid fuel such as gasoline supplied to the engine 7 is disposed at the upper part of the main frame 2.

  A rider seat 9 is provided at the rear of the fuel tank 8, a handle 11 is attached to the upper bracket 10 that supports the upper portion of the front fork 3, and a throttle grip (not shown) is provided on the right side of the handle 11. Is provided. The rider seated on the seat 9 can turn the handle 11 to turn the front wheel 4 and twist the throttle grip (not shown) to change the rotational output of the engine 7.

  A synthetic resin cowling 12 that covers the side is attached to the front of the vehicle body, and the rear of the cowling 12 covers the side and the lower portion of the engine 7. An air intake 13 is formed on the front surface of the cowling 12. An air cleaner box 28 is disposed below the fuel tank 8 and above the engine 7. The air cleaner box 28 opens forward, and is configured to take in air that flows in from the air intake port 13 of the cowling 12 due to traveling wind pressure.

[engine]
FIG. 2 is a left sectional view of the engine 7 shown in FIG. The engine 7 shown in FIG. 2 is a 4-cycle parallel 4-cylinder reciprocating engine, and is mounted on the motorcycle 1 (see FIG. 1). Four cylinders are arranged side by side and a crankshaft is an output shaft. (Not shown) is directed left and right. However, the number of cylinders, the layout of the cylinders, and the direction of the crankshaft of the engine according to the present invention are not limited thereto and can be changed as appropriate. FIG. 2 shows a cross section of only one cylinder, but the remaining cylinder and the cross section of the intake passage 30 corresponding to the remaining cylinder have substantially the same shape as shown in the figure.

  The engine 7 includes a cylinder head 20 connected to a cylinder block 16 (see FIG. 1) that houses four pistons (not shown). The cylinder head 20 is formed with a combustion chamber 21 provided individually for each piston, and a plug hole 22 for accommodating a plug (not shown) for igniting an air-fuel mixture sent into the combustion chamber 21. Yes. An exhaust port 23 extending forward and an intake port 24 extending rearward are communicated with the combustion chamber 21, and the air-fuel mixture is sent into the combustion chamber 21 through the intake port 24. An exhaust manifold 17 (see FIG. 1) is connected to the front portion of the cylinder head 20, and the gas after combustion is discharged to the outside through the exhaust port 23 and the inside of the exhaust manifold. The cylinder head 20 is provided with an intake / exhaust valve (not shown) that opens and closes the ports 23 and 24 at appropriate timings. By the operation of the intake / exhaust valve, intake, compression, and expansion ( Combustion) and exhaust are performed in this order.

[Intake system]
An intake device 25 is provided at the rear of the cylinder head 20. The intake device 25 has a configuration in which a holder 32, a throttle body 26, an intake duct 27, an air cleaner 28, and an introduction duct (not shown) are connected in order from the cylinder head 20 side. When these components are connected in series, the intake port 24 and the internal space of each component communicate with each other to form an intake passage 30 to the combustion chamber 21 of the engine 7. As will be described later, a so-called double injector system is applied to the engine 7 (see reference numerals 81 and 82), and fuel is injected at two locations in the intake passage 30 to send an air-fuel mixture into the combustion chamber 21. It has become.

  The throttle body 26 has an internal space 31. One end of the throttle body 26 is connected to the cylinder head 20 via the holder 32 from the rear side, and the central axis of the internal space 31 of the throttle body 26 extends rearward and upward from the engine 7 side.

  A main throttle valve 34 is built in the small diameter portion 33 that forms the downstream portion of the throttle body 26. The main throttle valve 34 includes a rotatable valve shaft 35 extending left and right on the central axis of the internal space 31, and a valve body 36 fixed to the valve shaft 35 and disposed in the internal space 31. A sub-throttle valve 38 is built in a large-diameter portion 37 that forms the upstream portion of the throttle body 26, and the sub-throttle valve 38 also includes a valve shaft 39 and a valve body 40 that have the same configuration as the main throttle valve 34. . The main throttle valve 34 is configured such that the valve shaft 35 is rotationally driven by a wire mechanically connected to the throttle grip (not shown), and the sub-throttle valve 38 is an electrically detected throttle grip twisting operation. The valve shaft 39 is configured to be driven and controlled based on the amount. When the rotational positions of the valve bodies 36 and 40 (that is, the opening degree of the throttle valves 34 and 38) change due to the rotation of the valve shafts 35 and 39, the flow path resistance of the internal space 31 of the throttle body 26 changes, and the combustion chamber The amount of air (air mixture) sent to 21 is adjusted, and the output of the engine 7 is changed.

  The intake duct 27 is formed of an elastic material such as rubber or a plastic material such as a synthetic resin material and has an internal passage 41, and is opposite to the other end of the throttle body 26, that is, the side connected to the engine 7. Is connected to the upstream end. On the outer peripheral surface of the intake duct 27, an engagement groove 42 for connection to an air cleaner box 43 constituting the air cleaner 28 is formed.

  The air cleaner box 43 is configured by vertically assembling a lower case 44 and an upper case 45 formed by injection molding of a synthetic resin material, and is disposed so as to cover the upper side of the engine 7.

  When the air cleaner box 43 is configured, an internal space 46 of the air cleaner box 43 surrounded by the inner surfaces of the cases 44 and 45 is formed. An inlet 47 for taking in air is formed at the front part of the lower case 44, and an outlet 48 to which the intake duct 27 is connected is formed at the lower rear part of the lower case 44. A filter element 49 that constitutes the air cleaner 28 is accommodated in the internal space 46. The filter element 49 divides the internal space 46 into an upstream dirty side 50 in which the inflow port 47 is formed and a downstream clean side 51 in which the outflow port 48 is formed. The dirty side 50 is disposed at the front lower part in the internal space 46, and the clean side 51 is disposed at the upper part and the rear lower part in the internal space 46.

  The bottom wall of the lower case 44 is provided with a hook-like engagement rib 52 integrally formed on the inner periphery of the outlet 48, and the engagement rib 52 is fitted in the engagement groove 42 of the intake duct 27. Combined. Since the engaging groove 42 is formed on the outer peripheral surface of the intake duct 27, the downstream portion is disposed outside (in this case, the lower side) of the air cleaner box 43 with respect to the engaging groove 42, and the upstream portion is the air cleaner box. 43 is disposed on the clean side 51 through the bottom wall of 43. When the intake duct 27 is formed of an elastic material such as rubber, the intake duct 27 can be easily attached to the air cleaner box 43 so as to have such an arrangement relationship. The upstream portion of the intake duct 27 extends rearward and upward from the position where the outflow port 48 is formed at the rear portion of the clean side 51, and an end thereof opens at the front upper portion of the clean side 51.

  When the intake port 24 is opened to perform intake in each cylinder, the intake port 24 becomes negative pressure, and the air flowing into the dirty side 50 from the air inlet 13 is filtered in the process of passing through the filter element 49, and is clean. Clean air is supplied to the side 51. The air on the clean side 51 flows into the internal passage 41 of the intake duct 27, passes through the internal space 31 of the throttle body 26 from the large diameter side toward the small diameter side, and flows into the intake port 24. In this process, fuel is mixed with air. In addition, immediately after the intake port 24 is opened or immediately before it is closed, the intake port 24 may instantaneously become positive pressure. In this case, a rebound phenomenon occurs and the air in the intake port 24 is directed in the opposite direction. Flowing. In this way, the intake passage 30 is arranged in order from the upstream side to the internal passage of the introduction duct (not shown), the internal space 46 of the air cleaner box 43, the internal passage 41 of the intake duct 27, the internal space 31 of the throttle body 26, and the holder 32. The internal passage 32a and the intake port 24 communicate with each other.

  The intake duct 27 has a peripheral wall 61 with an engagement groove 42 formed on the outer peripheral surface, and a rear wall 62 projects upward from the rear portion of the peripheral wall 61. A semi-cylindrical main wall 63 having a lower height than the rear wall 62 is continuously formed on the front side of the rear wall 62. A space formed by the inner wall surface of the main wall 63 and the inner wall surface of the rear wall 62 is the main passage 53 of the internal passage 41. On the front side of the main wall 63, a semi-cylindrical subwall 64 having a lower height than the main wall 63 is continuously formed. The sub wall 64 is provided so as to protrude upward from the front portion of the peripheral wall 61 having the engaging groove 42, and the rear end portion of the sub wall 64 is formed at the lower rear end portion of the main wall 63 and the lower end portions of the rear wall 62. It is continuous. A space formed by the inner wall surface of the sub wall 64 and the outer wall surface of the main wall 63 is a sub passage 54 of the internal passage 41.

  FIG. 3 is a longitudinal sectional view of the intake device 25 cut along the line III-III in FIG. 2, and the configuration of the intake device 25 will be further described in view of being provided in a multi-cylinder engine. As partially shown in FIG. 3, the intake passage 30 has one passage common to the four cylinders in a section from the air inlet 13 (see FIG. 1) to the clean side 51 of the air cleaner box 43. ing.

  In the lower case 44, four outlets 48 corresponding to the number of cylinders are formed side by side, and an intake duct 27 is connected to each outlet 48. The left one of the throttle bodies 26 has two internal spaces 31 communicating with the internal passages 41 of the two left intake ducts 27, and the right one includes the internal passages 41 of the two right intake ducts 27. It has two internal spaces 31 that communicate with each other.

  In this way, as shown in FIG. 3, the intake passage 30 has four independent systems corresponding to each cylinder in the section from the internal passage 41 of the intake duct 27 to the intake port 24 (see FIG. 2). Has a passage. These four paths correspond to the first cylinder, the second cylinder, the third cylinder, and the fourth cylinder in order from the left side of FIG. In the engine 7, each stroke of intake, compression, expansion (combustion) and exhaust is performed, for example, every time a crankshaft (not shown) rotates 180 degrees, for example, first cylinder, third cylinder, fourth cylinder, second cylinder The first cylinder, the third cylinder, and so on are performed in this order.

  FIG. 4 is a perspective sectional view of the intake device 25 shown in FIG. 3, showing a sectional shape of the intake duct 27 corresponding to the third cylinder and a part of an outer shape of the intake duct 27 corresponding to the fourth cylinder. Yes. As shown in FIGS. 3 and 4, the intake ducts 27 (hereinafter also referred to as first intake ducts 56) corresponding to the first cylinder and the fourth cylinder have the same shape, and the second cylinder and Each intake duct 27 corresponding to the third cylinder (hereinafter also referred to as a second intake duct 57) has the same shape. The first intake duct 56 and the second intake duct 57 have different shapes.

  The first intake duct 56 is formed with a shorter upstream end than the second intake duct 57, and the first intake duct 56 protrudes at the clean side 51 in the air cleaner box 43 compared to the second intake duct 57. Is getting smaller.

[Fuel system]
Returning to FIG. 2, the engine 7 adopts a so-called double injector system, and includes a downstream injector 81 that injects fuel into the downstream portion of the intake passage 30, and an upstream injector that injects fuel into the upstream portion of the intake passage 30. 82. The injectors 81 and 82 are driven and controlled by an ECU (not shown). For example, the downstream injector 81 mainly operates from the low load low rotation state to the high load high rotation state, and the upstream injector 82. Operates mainly when the engine 7 is in a high load and high rotation state.

  The downstream injector 81 is attached to the rear portion of the throttle body 26 from the outside. The fuel injection portion 81 a of the downstream injector 81 is disposed downstream of the valve body 36 of the main throttle valve 34 in the internal space 31 of the throttle body 26. The downstream injectors 81 are individually provided for each cylinder, and the four downstream injectors 81 are arranged side by side on the left and right. Each of the downstream injectors 81 is connected to a downstream delivery pipe 83 that extends from the left to the right of the head, and the downstream delivery pipe 83 is connected to an upstream delivery pipe 85 via a fuel pipe 84. The downstream delivery pipe 83 is connected to the fuel tank 8 (see FIG. 1) via a pipe (not shown). As a result, the fuel in the fuel tank 8 is distributed and supplied to each upstream injector 82 via the downstream delivery pipe 83, the fuel pipe 84, and the upstream delivery pipe 85. The downstream injector 81 and the upstream injector 82 inject the supplied fuel into the intake passage 30 at an appropriate timing.

  As shown in FIG. 2, the upstream injector 82 is attached to the rear upper part of the upper case 45 of the air cleaner 28 from above, and the fuel injection portion 86 is disposed in the internal space 46 of the air cleaner box 43. As shown in FIG. 3, the upstream injectors 82 are individually provided for each cylinder, and the four upstream injectors 82 are arranged side by side on the left and right. Each upstream injector 82 is connected to an upstream delivery pipe 85 extending left and right at the head. Thus, the liquid fuel in the fuel tank 12 (see FIG. 1) is distributed and supplied to each upstream injector 82 via the upstream delivery pipe 85, and the upstream injector 82 cleans the supplied fuel at an appropriate timing. Injected from 51 to the upstream end opening of the main passage 53 of the intake duct 27.

  As shown in FIG. 3, four injector attachment portions 87 for attaching each upstream injector 82 are formed side by side on the rear portion of the upper wall of the upper case 45. Each injector mounting portion 87 is formed in a bowl shape and has a large-diameter upper opening and a small-diameter lower opening, each of which is circular. A stay 88 made of a metal plate is fixed to the outer upper surface of the rear portion of the upper wall of the upper case 45 with a bolt. The stay 88 is integrally formed with four boss portions 89 protruding from the mounting surface facing the outer surface of the air cleaner box 43, and each boss portion 89 is accommodated in the injector mounting portion 87 through the upper opening. . Each boss portion 89 has a through hole, and one upstream injector 82 is accommodated in each through hole of each boss portion 89 from the upper side of the stay 88. Since the upstream injector 82 has a stepped cylindrical shape, when the upstream injector 82 is accommodated in the through hole, the stepped surface abuts the boss portion 89 and is held in the through hole. It becomes. Thus, when the upstream injector 82 is fixed to the air cleaner box 43 via the stay 88, the fuel injection portion 86 of each upstream injector 82 is disposed so as to slightly protrude from the lower opening of the injector mounting portion 87. . Further, the central axis of each upstream injector 82 substantially coincides with the central axis of the main passage 53 of the corresponding intake duct 27 and the central axis of the internal space 31 of the throttle body 26, and the fuel injection portion 86 is the main axis of the intake duct 27. It arrange | positions so that the center part of the upstream end opening of the channel | path 53 may be opposed.

  As shown in FIG. 2, the fuel guide portion 90 protrudes integrally from the inner surface of the upper case 45. The fuel guide portion 90 is formed in a cylindrical shape and extends from the outer peripheral edge of the lower opening of the injector attachment portion 87 toward the outlet 48. For this reason, a ring-shaped rib 91 protruding radially inward with respect to the root portion of the fuel guide portion 90 is formed around the lower opening of the injector mounting portion 87. The ring-shaped rib 91 and the inner peripheral surface of the root portion of the fuel guide portion 90 are surrounded.

  The diameter of the fuel guide portion 90 is slightly increased as the inner peripheral surface of the cylindrical portion moves toward the tip. On the other hand, the thickness of the fuel guide portion 90 decreases toward the tip in order to avoid an increase in size as a whole, and the outer diameter thereof is substantially constant in the axial direction. When viewed in the axial direction, the front end opening of the fuel guide portion 90 is arranged in an inner region of the contour line of the upstream end opening of the intake duct 27, and the contour of the front end opening of the fuel guide portion 90 and the upstream end opening of the intake duct 27 is arranged. A substantially annular clearance is formed between the lines. Here, the central axis of the fuel guide portion 90 substantially coincides with the central axis of the injector mounting portion 87, and substantially coincides with the central axis of the upstream injector 82 and the central axis of the main passage 53 of the intake duct 27. Yes. However, the center axis lines of the fuel guide portion 90 and the injector mounting portion 87 do not necessarily coincide with each other. The front end opening of the fuel guide portion 90 is disposed around the upstream end opening of the main passage 53 of the intake duct 27 and is disposed at least on the downstream side (lower side here) from the rear wall 62.

  By having such a fuel guide portion 90, the fuel injected from the upstream injector 82 passes through the inside of the fuel guide portion 90 and is sent into the intake passage 30 through the front end opening of the fuel guide portion 90. It is done. Since the front end opening of the fuel guide portion 90 is disposed around the upstream end opening of the main passage 53 of the intake passage 27, almost all of the fuel injected from the fuel guide portion 90 is introduced into the main passage 53 of the intake duct 27. Is done. As a result, the combustion efficiency is improved, and the deterioration of engine output performance and exhaust gas performance can be suppressed.

  Further, even when fuel is injected from the upstream injector 82 while air is being blown back in the intake passage 30, the fuel guide 90 is not provided and the fuel is injected into the clean side 51. In comparison, the possibility that the fuel flows back through the clean side 51 is reduced, and the fuel is easily introduced into the main passage 53 of the intake duct 27. For this reason, the possibility that the injected fuel adheres to the filter element 49 is reduced, and the performance degradation of the filter element 49 can be suppressed.

  In the test conducted by the present applicant, when such a fuel guide portion 90 is provided, the fuel injected from the upstream injector 82 draws a tornado-like trajectory in the inner space of the fuel guide portion 90 and opens at the tip opening. It is known that it may flow towards you. Thus, by providing the fuel guide portion 90, the fuel injected from the upstream injector 82 is likely to form a mist when flowing into the intake passage 30 from the front end opening, and as a result, the combustion efficiency can be improved. . In addition, the inside of the fuel guide portion 90 is communicated with the intake passage 30 in a portion excluding the tip opening, such as a slit extending in the axial direction or a circular or other through-hole formed in the outer wall of the fuel guide portion 90, so that the upstream side The fuel injected from the injector 82 can pass through the inside of the fuel guide portion 90 in a similar complicated locus.

  Further, since the fuel guide portion 90 is integrally formed when the upper case 45 of the air cleaner box 43 is formed, a dedicated part can be omitted, and the structure can be prevented from becoming complicated. Can do.

  Referring to FIG. 3, the fuel guide portion 90 is individually provided for each upstream injector 82. For this reason, in an engine having a plurality of cylinders, the combustion efficiency of each cylinder can be improved.

  In addition, the axial lengths of the four fuel guide portions 90 are equal to each other, but the protruding height of the first intake duct 56 is smaller than that of the second intake duct 57 as described above. For this reason, referring to FIGS. 3 and 4, the tip opening of the fuel guide portion 90 corresponding to the second and third cylinders is located downstream of the edge of the main wall 63 of the second intake duct 57, The distal end portion of the fuel guide portion 90 is disposed in the main passage 53 of the second intake duct 57. On the other hand, the front end opening of the fuel guide portion 90 corresponding to the first and fourth cylinders is located upstream of the edge of the main wall 63 of the first intake duct 56, and the front end portion of the fuel guide portion 90 is The first intake duct 56 is disposed in the main passage 53.

  Therefore, in the second and third cylinders, the flow resistance of the main passage 53 of the second intake duct 57 increases and the engine output in the high rotation range decreases, but the effect of suppressing the back flow of fuel is increased. be able to. In the first and fourth cylinders, the reverse flow of the fuel is slightly more likely to occur than in the second and third cylinders, but the flow resistance of the first intake duct 56 does not increase, so the engine in the high rotation region The output can be kept high. However, also in the first and fourth cylinders, the fuel backflow can be suppressed by providing the fuel guide portion 90. In this way, by changing the arrangement of the tip of the fuel guide portion 90 with respect to the upstream end opening in the main passage 53 of the intake duct 27 between the cylinders, the engine output in the high rotation range is increased and the backflow of fuel is prevented. To do both.

  In addition, since the relative positional relationship between the upstream end opening of the intake duct 27 and the front end opening of the fuel guide portion 90 suffices to be like this, the protrusion height of the intake duct is set so as to satisfy such a relationship. All may be the same, and the length of the fuel guide portion may be varied depending on the cylinder.

(Second Embodiment)
FIG. 5 is a right sectional view of an intake device for an engine provided with a fuel injection structure according to a second embodiment of the present invention. In the following description, the same components as those in the above embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 5, the upstream injector 82 is held by the boss portion 89 of the stay 88, and the central axis of the upstream injector 82 substantially coincides with the central axis of the internal passage 141 of the intake duct 127. Note that the internal passage 141 of the intake duct 127 is not divided into a main passage and a sub-passage as in the first embodiment.

  A cap member 191 is fitted on the upper case 145 of the air cleaner box 143 so as to cover the lower opening of the injector mounting portion 187. A cylindrical fuel guide portion 190 is further fitted to the lower end portion of the cap member 191. The cap member 191 is made of a material having elasticity such as rubber and is firmly bonded to the upper case 145 and the fuel guide portion 190. The fuel guide portion 190 is bonded to the elastically deformable cap member 191 at the base end portion thereof, that is, in the vicinity of the fuel injection portion 86 surrounding the fuel injection portion 86 of the upstream injector 82. The fuel guide portion 190 is fixed to the upper case 145 so as to be swingable with the adhesive portion as a fulcrum 199.

  A rib 192 is provided on the outer peripheral surface of the front end portion of the fuel guide portion 190, and the front end portion of the link 193 is swingably connected to the rib 192. A rod 194 is swingably connected to the base end portion of the link 193, and this rod 194 passes through the upper wall of the upper case 145 and is drawn out of the air cleaner box 143. The rod 194 is provided to be able to advance and retreat in a certain direction. A packing 195 is provided on the upper wall of the upper case 145 to guide the movement of the rod 194 and to ensure the airtightness of the internal space 146 of the air cleaner box 143.

  A swing actuator 171 that drives the rod 194 to advance and retreat is connected to the tip of the rod 194. The swing actuator 171 may be an electric motor or a solenoid.

  In addition, the motorcycle of the present embodiment is provided with a control device 172 that controls the operation of the swing actuator 171. The control device 172 includes sensors for detecting the operating state of the engine, for example, a throttle opening sensor 173 for detecting the opening of the main throttle valve, a rotation speed sensor 174 for detecting the engine speed, and a vehicle speed for detecting the vehicle speed. Detection signals from the sensor 175, the temperature sensor 176 for detecting the engine wall surface temperature or the cooling water temperature, and the like are input. The control device 172 controls the swing actuator 171 according to these input detection signals. The rod 194 advances and retreats according to the operation of the swing actuator 171, and the fuel guide portion 190 connected to the rod 194 via the link 193 according to the advance and retreat direction of the rod 194 swings with the joint portion with the cap 191 as a fulcrum. Move. The central axis of the fuel guide portion 190 that has swung in this manner is inclined with respect to the central axis of the upstream injector 82 and the central axis of the internal passage 141 of the intake duct 127. Since the bonding portion with the cap 191 is set at the base end portion of the fuel guide portion 190, that is, in the vicinity of the fuel injection portion 86 of the upstream injector 82, the upstream end of the intake duct 127 at the tip opening of the fuel guide portion 190 is set. The posture with respect to the side opening changes.

  As described above, the posture of the front end opening of the fuel guide portion 190 is variable and the direction of the central axis of the fuel guide portion 190 is variable, so that the fuel injection direction can be changed without changing the posture of the front end injector 82. It is adjusted according to the direction of the central axis of the part 190.

  For example, the swing actuator 171 is controlled according to the opening of the sub-throttle valve, and the fuel guide portion 190 is moved so that the edge of the valve body of the sub-throttle valve is positioned on the extension line of the central axis of the fuel guide portion 190. Rock. As a result, the injected fuel always hits the edge of the valve body and tends to become mist-like and easily diffuse. As a result, the combustion efficiency is improved.

  The fuel guide unit 190 does not necessarily have to be configured to swing automatically in accordance with the operating state of the engine, and may be configured such that a maintenance worker can perform tuning by manually moving the rod 193 back and forth.

(Third embodiment)
FIG. 6 is a right side view of an intake device for an engine provided with a fuel injection structure according to a third embodiment of the present invention. In the following description, the same components as those of the above-described embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 6, the upstream injector 82 is held by the boss portion 89 of the stay 88, and the central axis of the upstream injector 82 substantially coincides with the central axis of the internal passage 141 of the intake duct 127. The upper case 245 of the air cleaner box 243 is integrally formed with a first fuel guide portion 291 that protrudes in a cylindrical shape from the outer periphery of the lower opening of the injector mounting portion 287. A cylindrical second fuel guide portion 292 is slidably fitted on the outer peripheral side of the first fuel guide portion 291. The fuel guide portion 290 of the present embodiment includes these first and second fuel guide portions 291 and 292, and can be expanded and contracted by sliding the second fuel guide portion 292 with respect to the first fuel guide portion 291.

  A rib 293 is provided on the outer peripheral surface of the base end portion of the second fuel guide portion 292, and the base end portion of the link 294 is swingably connected to the rib 293. A rod 295 is swingably connected to the tip of the link 294. The rod 295 passes through the upper wall of the upper case 245 and is drawn out of the air cleaner box 243 so that it can advance and retreat in one direction. A packing 296 is provided on the upper wall of the upper case 245 in order to guide the movement of the rod 295 and to ensure the airtightness of the internal space 246 of the air cleaner box 243.

  A telescopic actuator 271 that drives the rod 295 to advance and retract is connected to the tip of the rod 295. The swing actuator 271 may be an electric motor or a solenoid.

  The motorcycle of this embodiment is provided with a control device 272 that controls the operation of the telescopic actuator 271. The control device 272 receives detection signals from sensors for detecting the operating state of the engine, for example, the throttle opening sensor 173, the rotation speed sensor 174, the vehicle speed sensor 175, the temperature sensor 176, and the like. The control device 272 controls the telescopic actuator 271 in accordance with these input detection signals. The rod 294 advances and retreats according to the operation of the telescopic actuator 271, and the second fuel guide portion 292 slides and the fuel guide portion 290 expands and contracts according to the advance and retreat direction of the rod 294. Thereby, the distance from the fuel injection part 86 to the front end opening of the fuel guide 290 is variable.

  In this way, the tip opening of the fuel guide portion 290 moves to change the distance from the upstream end opening of the intake duct 127, so that the attitude of the tip injector 82 is not changed, and the flow of the internal passage 141 of the intake duct 127 is changed. The road resistance can be adjusted. For example, when the engine is in a low load and low rotation state, the fuel guide portion 290 is extended, and when the engine is in a high load and high rotation state, the fuel guide portion 290 is reduced. As a result, the torque can be increased in the low load and low rotation state, and the engine output can be increased in the high load and high rotation state.

  The fuel guide unit 290 does not necessarily have to automatically expand and contract depending on the operating state of the engine, and is configured so that a maintenance worker can perform tuning by manually moving the rod 294 back and forth. May be.

(Fourth embodiment)
FIG. 7 is a right side view of an intake device for an engine equipped with a fuel injection structure according to a fourth embodiment of the present invention. In the following description, the same components as those of the above-described embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 7, the upstream injector 82 is held by the boss portion 89 of the stay 88, and the central axis of the upstream injector 82 coincides with the central axis of the internal passage 141 of the intake duct 127. In the upper case 345 of the air cleaner box 343, a cylindrical first fuel guide portion 391 extending from the outer periphery of the lower opening of the injector mounting portion 387 toward the intake duct 27 side is rotatable and cannot be linearly moved in the axial direction. It is attached. A male screw is cut on the outer peripheral surface of the first fuel guide portion 391, and a second fuel guide portion 392 having a female screw cut on the inner peripheral surface thereof is screwed on the outer peripheral side of the first fuel guide portion 391. Match. The fuel guide portion 390 of the present embodiment includes these first and second fuel guide portions 391 and 392.

  The upper case 345 is integrally formed with a flat guide wall 393 extending from the outer peripheral portion of the lower opening of the injector mounting portion 387 toward the intake duct 27 side. The guide wall 393 is formed with a slit 394 extending in parallel with the central axis of the upstream injector 82 and the central axes of the first and second fuel guide portions 391 and 392, and the second fuel is contained in the slit 394. A guide piece 395 protruding from the outer peripheral surface of the guide portion 392 is disposed. As described above, the rotation of the second fuel guide portion 392 is restricted by the guide piece 395 being accommodated in the slit 394, while the second fuel guide portion 392 is allowed to move in the axial direction.

  A transmission mechanism 396 for transmitting a rotational driving force around its axis to the first fuel guide portion 391 is connected to the base end portion of the first fuel guide portion 391. The components of the transmission mechanism 396 are pulled out from the upper wall of the upper case 345 of the air cleaner box 343, and an expansion / contraction actuator 371 for inputting a rotational driving force to the transmission mechanism 396 is provided outside the air cleaner box 343. Yes. The telescopic actuator 371 is composed of, for example, an electric motor.

  In addition, the motorcycle of the present embodiment is provided with a control device 372 that controls the operation of the telescopic actuator 371. The control device 372 receives detection signals from sensors that detect the operating state of the engine, such as the throttle opening sensor 173, the rotation speed sensor 174, the vehicle speed sensor 175, the temperature sensor 176, and the like. The control device 372 controls the telescopic actuator 371 according to these input signals. The first fuel guide portion 391 rotates around its axis in accordance with the operation of the telescopic actuator 371, and the second fuel guide portion 392 moves in the rotation axis direction in accordance with the rotation direction of the first fuel guide portion 391. Thereby, the fuel guide part 390 expands and contracts.

  In this way, the tip opening of the fuel guide portion 390 moves to change the distance from the upstream end opening of the intake duct 127, so that the flow of the internal passage 141 of the intake duct 127 does not change without changing the posture of the tip injector 82. The road resistance can be adjusted.

  The embodiment according to the present invention has been described above, but the present invention is not limited to the above configuration and can be changed as appropriate. For example, the fuel guide portion may be provided to be extendable and swingable. In this case, for example, the fuel guide portion may be formed in a bellows shape in order to realize a configuration that can be expanded and contracted. Further, the fuel supply method is not limited to the so-called double injector method, and when the injector is arranged on the upstream side of the intake duct, the present invention can be suitably applied to an engine including only the injector. it can.

  The present invention has an excellent effect of preventing the fuel injected from the injector from being blown back, and can be widely applied to a fuel injection structure including an injector that injects fuel upstream of the intake duct. In particular, the present invention can be suitably applied to vehicles such as a high-power type engine that employs a so-called double injector system, and motorcycles, small planing boats, and rough terrain vehicles equipped with the same.

1 is a left side view of a motorcycle including a fuel injection structure according to a first embodiment of the present invention. It is a left sectional view of the engine shown in FIG. It is a longitudinal cross-sectional view of the intake device of the engine shown cut along the line III-III shown in FIG. FIG. 4 is a perspective sectional view of the intake device shown in FIG. 3. It is right side sectional drawing of the intake device of the engine provided with the fuel-injection structure which concerns on 2nd Embodiment of this invention. It is a right view of the intake device of the engine provided with the fuel-injection structure concerning 3rd Embodiment of this invention. It is a right view of the intake device of the engine provided with the fuel-injection structure which concerns on 4th Embodiment of this invention.

Explanation of symbols

1 Motorcycle 9 Engine 25 Intake device 27, 127 Intake duct 28 Air cleaner 30 Intake passage 43, 143, 243, 343 Air cleaner box 82 Upstream injector 86 Fuel injection part 90, 190, 290, 390 Fuel guide part 171 Swing actuator 172 Control device (oscillation controller)
271, 372 Telescopic actuator 272, 372 Control device (extension control unit)

Claims (9)

An injector that injects fuel toward an upstream end opening of an intake duct that forms part of an intake passage to the engine;
A fuel guide part provided in the intake passage and surrounding a fuel injection part of the injector;
The fuel guide portion extends toward the upstream end opening of the intake duct ;
The air cleaner box has an injector mounting portion for mounting the injector, and the fuel guide portion integrally protrudes from the injector mounting portion of the air cleaner box and extends toward the upstream opening of the intake duct. And
The fuel injection structure , wherein the injector is attached to the injector attachment portion from outside the air cleaner box, and a delivery pipe for distributing fuel to the injector is disposed outside the air cleaner box . The fuel injection structure according to claim 1 , wherein a distal end portion of the fuel guide portion is disposed in the intake duct. The engine has a plurality of cylinders, the intake duct and the injector are provided for each cylinder, and the tip of the fuel guide part is arranged in the intake duct for some cylinders, and the remaining cylinders The fuel injection structure according to claim 2, wherein the tip end portion of the fuel guide portion is located upstream of the upstream end opening of the intake duct. The fuel injection structure according to any one of claims 1 to 3, wherein the fuel guide portion has an inner peripheral surface that expands in diameter and decreases in thickness toward the tip. An injector that injects fuel toward an upstream end opening of an intake duct that forms part of an intake passage to the engine;
A fuel guide portion provided in the intake passage and surrounding a fuel injection portion of the injector;
With
The fuel guide portion extends toward the upstream end opening of the intake duct;
Fuel injection structure you characterized in that the fuel guide portion is provided to be swingable with a fulcrum proximal portion.   A swing actuator that swings the fuel guide, and a swing control unit that swings the fuel guide portion by operating the swing actuator according to an operating state of the engine. Item 6. The fuel injection structure according to Item 5. An injector that injects fuel toward an upstream end opening of an intake duct that forms part of an intake passage to the engine;
A fuel guide portion provided in the intake passage and surrounding a fuel injection portion of the injector;
With
The fuel guide portion extends toward the upstream end opening of the intake duct;
Fuel injection structure you wherein fuel guide portion is stretchable.   The expansion / contraction actuator which expands / contracts the fuel guide part, and the expansion / contraction control part which expands / contracts the fuel guide part by operating the expansion / contraction actuator according to the operating state of the engine. Fuel injection structure.   A vehicle comprising the fuel injection structure according to any one of claims 1 to 8.

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