JP4555413B2 - Fuel injection device for backbone type motorcycle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention includes a front half straight portion that extends downward and straight from the head pipe that supports the front fork, a second half straight portion that extends more slowly and rearward downward than the front half straight portion, and a space between both straight portions. A body frame is composed of a backbone composed of intermediate bent portions that are continuously connected and a rear frame that is integrally coupled to the rear end of the backbone and supports a rear fork, and a cylinder is formed on the rear frame below the backbone. An engine is mounted to project the block and cylinder head substantially horizontally toward the front. Between the cylinder head and the air cleaner attached to the front end of the backbone, the engine is arranged below the backbone and tilted substantially rearward and downward. Connected via an intake passage that has a throttle valve in the intake passage. Relates motorcycle combustion engine, in particular, said so comprises a fuel injection valve into the intake passage, a fuel injection device in the backbone-type motorcycle.
[0002]
[Prior art]
Such a backbone type motorcycle is widely used worldwide as a small motorcycle with the trade name “Super Cub”, which is related to the manufacture of the applicant company. In this case, a vaporizer is installed in the middle of the intake passage. (See, for example, Japanese Utility Model Publication No. 62-39993).
[0003]
[Problems to be solved by the invention]
In the backbone type motorcycle, when a fuel injection valve is attached to the intake passage in place of the carburetor without changing the body frame or the engine layout, the injected fuel is supplied from the fuel injection valve to the cylinder head of the engine. In order to make sure that it is directed to the intake port that opens on the upper surface of the intake passage, it must be attached to the upper side wall of the intake passage. However, since the backbone of the frame is disposed relatively close above the intake passage, the fuel injection valve easily interferes with the backbone and cannot be easily attached to the upper side wall of the intake passage. .
[0004]
Accordingly, the present invention can attach the fuel injection valve to the upper side wall of the intake passage without interfering with the backbone of the vehicle body frame without changing the layout of the conventional vehicle body frame and engine. It is an object of the present invention to provide a fuel injection device for the backbone type motorcycle that can inject fuel toward an intake port of a cylinder head.
[0005]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention provides a front half straight portion that extends downward and straight from the head pipe that supports the front fork, and a rear half that extends linearly downward and rearward from the front half straight portion. A vehicle body frame comprising a backbone formed of an arc-shaped intermediate bent portion in a side view of the vehicle that continuously connects the linear portion and both linear portions, and a rear frame that is integrally coupled to the rear end of the backbone and supports a rear fork. An engine for projecting the cylinder block and the cylinder head substantially horizontally toward the front below the backbone, and an intake port opening on an upper surface of the cylinder head, and a front end portion of the backbone. Intake air that is disposed below the backbone and tilts backward and downward between the air cleaner attached to the Connected via road, it provided the throttle valve at an intermediate portion of the intake passage rotatably in the backbone-type motorcycle, the intake passage, after along the half straight line portion is opened and closed by the throttle valve A throttle body having an intake passage extending obliquely downward, and an intake pipe having an obtuse bend and connecting between the intake passage and the intake port, and an intake pipe portion of the intake passage and A portion of the intake passage downstream from the rotation center of the throttle valve , as viewed from the side of the vehicle, a downward extension line of a boundary line between the front half straight portion and the intermediate bent portion, and a boundary between the latter half straight portion and the intermediate bent portion The middle point of the outer curve at the intermediate bent portion of the backbone is located above the upper extension surface of the mating surfaces of the cylinder block and the cylinder head. Also located on the front side, wherein the upper wall of the bent portion of the intake pipe, the upright fuel injection valve capable of injecting fuel downwardly into the intake port, the valve is a side view of the vehicle The upper end of the valve is located in front of the middle point, and the fuel supply pipe fitted to the upper end is opposed to and close to the lower surface of the intermediate bent portion. The fuel is injected toward the intake port of the head.
[0006]
According to this feature, it is possible to rationally use the narrow space between the backbone of the vehicle body frame and the intake passage without changing the layout of the conventional vehicle body frame or engine, and to adjust the intake passage (particularly, the bending of the intake pipe). The fuel injection valve can be attached to the upper side wall of the fuel tank, so that fuel can be injected from the valve toward the intake port of the cylinder head, and loss due to the fuel adhering to the pipe wall can be reduced. it can.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.
[0008]
1 to 4 show a first embodiment of the present invention. FIG. 1 is a side view of a backbone type motorcycle, FIG. 2 is a side view around an engine and an intake system of the motorcycle, and FIG. Fig. 4 is an enlarged side view around the fuel injection device in the intake system of Fig. 4, Fig. 4 is a view taken in the direction of arrow 4 in Fig. 3, and Fig. 5 is a side view similar to Fig. 3, showing a second embodiment of the present invention.
[0009]
First, a first embodiment of the present invention will be described with reference to FIGS. In FIG. 1, a vehicle body frame F of a motorcycle M is welded to a rear side surface of a head pipe 1 at a front end, and is welded to a backbone Ff made of a steel pipe extending obliquely rearwardly downward and a rear end of the backbone Ff. A rear frame Fr made of a steel plate is configured. A front fork 2 that pivotally supports the front wheel Wf is pivotally supported on the head pipe 1, and a rear fork 3 that pivotally supports the rear wheel Wr is pivotally supported on the rear frame Fr. The rear cushion 4 is connected between the rear frames Fr. A saddle 5 is attached to the upper surface of the rear frame Fr, and the fuel tank 6 is housed and held in the rear frame Fr immediately below the saddle 5. Further, the crankcase 7 of the engine E is attached to the front end of the rear frame Fr below the connection point with the backbone Ff. The engine E has a cylinder block 8 that protrudes from the front surface of the crankcase 7 and is arranged substantially horizontally, and a cylinder head 9 is joined to the front surface thereof. An air cleaner 10 is attached to the front end portion of the backbone Ff, and this is connected to an intake port (see FIG. 2) of the cylinder head 9 via an intake passage 12 disposed below the backbone Ff.
[0010]
The backbone Ff, the cylinder block 8, the cylinder head 9, the air cleaner 10, and the intake passage 12 are covered with a leg shield 13 attached to the vehicle body frame F.
[0011]
As shown in FIGS. 2 and 3, the backbone Ff is coupled to the head pipe 1 and is inclined rearward downward and extends linearly in the front half straight portion 14a, and the front half straight portion 14a is inclined more slowly than the front half straight portion 14a. The rear straight line portion 14b extends linearly and is coupled to the rear frame Fr, and the intermediate bent portion 14c having a radius of curvature R that continuously couples the straight line portions 14a and 14b. The cylinder head 9 is located below the intermediate bent portion 14c, and the intake port 11 is opened on the upper surface of the cylinder head 9. An opening end of the intake port 11 to the combustion chamber 16 is opened and closed by an intake valve 15.
[0012]
The air cleaner 10 is disposed directly below the front half straight portion 14a of the backbone Ff and has a cleaner case 17 whose front surface is opened, a case cover 18 which is coupled to the cleaner case 17 and closes its open surface, and the cleaner case 17 and The cleaner element 19 is sandwiched between the case covers 18 and an inlet duct 20 connected to the upper end of the case cover 18. A connection hole 21 for the intake passage 12 is provided in the bottom wall of the cleaner case 17. Then, the inlet duct 20 and the cleaner case 17 are screwed to the front half straight portion 14a of the backbone Ff.
[0013]
The above is no different from the layout of a conventional small motorcycle.
[0014]
The intake passage 12 includes a horn pipe 22 that is fitted into the connection hole 21 and enters the cleaner case 17, an intake pipe 23 that is coupled to the upper surface of the cylinder head 9 to communicate with the intake port 11, and A throttle body 24 is connected between the horn pipe 22 and the intake pipe 23. The horn tube 22 has an obtuse bend in the middle and has a substantially L shape with the downstream opening end facing backward and downward. The intake pipe 23 also has an obtuse bend in the middle and has an upstream opening end. The throttle body 24, which is substantially L-shaped with the pipe facing upward and inclined to connect the pipes 22 and 23, is a straight intake passage 24a that communicates the inside of the pipes 22 and 23. A butterfly throttle valve 25 that opens and closes the intake passage 24 a is pivotally supported by the throttle body 24. In this way, the intake passage 12 is disposed substantially along the backbone Ff. Then, an intake pipe 23 portion of the intake passage 12, a fuel injection valve 30, the intake passage 24a, and the downstream portion from the rotation center 25a of the throttle valve 25, as shown in FIG. 2, When viewed from the side of the vehicle, it is disposed in a region sandwiched between a downward extension of the boundary line of the front half straight portion 14a and the intermediate bent portion 14c of the backbone Ff and a lower extension line of the boundary line of the rear half straight portion 14b and the intermediate bent portion 14c. The
[0015]
An electromagnetic fuel injection valve 30 is erected on the upper side wall of the bent portion of the substantially L-shaped intake pipe 23. That is, a boss 27 having a mounting hole 26 is integrally formed on the upper side wall of the bent portion of the intake pipe 23, and the lower end portion of the fuel injection valve 30 is fitted into the valve mounting hole 26 via the seal member 28. The A fuel inlet is opened at the upper end surface of the fuel injection valve 30 and a fuel injection hole is opened at the lower end surface. The fuel injection valve 30, the outer curve in the injection fuel 31 from the fuel injection hole toward the downstream end that is specifically opened and closed by an intake valve 15 of the intake port 11, and the upper end portion is an intermediate bent portion 14c of the backbone Ff It arrange | positions so that it may come ahead from the midpoint 32. 2 and 3, the midpoint 32 is located on the front side of the upper extension surface of the mating surfaces of the cylinder block 8 and the cylinder head 9.
[0016]
As shown in FIGS. 3 and 4, a mounting hole 35 that opens to the side wall of the fuel supply pipe 34 is fitted to the upper end portion of the fuel injection valve 30 via a seal member 36. The fuel supply pipe 34 is disposed directly below the backbone Ff, perpendicular to the axis Y of the backbone Ff, horizontally, that is, in the left-right direction of the vehicle body , and fitted to the upper end of the fuel injection valve 30. As shown in FIGS. 3 and 4, the fuel supply pipe 34 is opposed to and close to the lower surface of the intermediate bent portion 14 c. A fuel conduit 39 connected to a discharge port of a fuel pump 38 (see FIG. 1) disposed in the fuel tank 6 is connected to one end of the fuel supply pipe 34, and an injection pressure regulator 40 is connected to the other end. Are concatenated.
[0017]
As shown in FIG. 4, the injection pressure regulator 40 includes a regulator body 42 having a fuel chamber 41 communicating with the fuel supply pipe 34, a cap 44 having a boost negative pressure chamber 43 and coupled to the regulator body 42, And a diaphragm 45 that is sandwiched between the regulator body 42 and the cap 44 and partitions the fuel chamber 41 and the boost negative pressure chamber 43. A valve seat 47 in which a fuel return hole 46 opens is provided at the center of the regulator body 42, and a valve body 48 that can be seated on the valve seat 47 is attached to the center of the diaphragm 45 so as to be able to swing. A valve spring 49 that urges the valve body 48 toward the valve seat 47 through the diaphragm 45 is accommodated in the boost negative pressure chamber 43. The boost negative pressure chamber 43 communicates with the intake pipe 23 via a negative pressure conduit 50, and the fuel return hole 46 communicates with the fuel tank 6 via a fuel return pipe 51. Further, a fuel filter 52 is provided in the fuel chamber 41.
[0018]
Next, the operation of the first embodiment will be described.
[0019]
During operation of the engine E, fuel in the fuel tank 6 is pumped into the fuel chamber 41 of the injection pressure regulator 40 through the fuel conduit 39 and the fuel supply pipe 34 by the fuel pump 38, and the fuel pressure causes the valve body 48 to be seated. Acts on the diaphragm 45 in a direction away from the diaphragm 47. On the other hand, the boost negative pressure in the intake pipe 23 is introduced into the boost negative pressure chamber 43 through the negative pressure conduit 50, and this boost negative pressure causes the valve body 48 to act as a valve seat, opposite to the load direction of the valve spring 49. Acts on the diaphragm 45 in a direction away from the diaphragm 47. Therefore, when the load on the engine E is small and the boost negative pressure is high, the valve opening pressure of the valve body 48 by the fuel in the fuel chamber 41 is low, and when the load on the engine E is large and the boost negative pressure is low, the fuel chamber The valve opening pressure of the valve body 48 due to the fuel 41 becomes high, and when the valve body 48 is opened, it returns to the fuel tank 6 through the fuel return pipe 51 that has flowed out of the fuel chamber 41 into the fuel return hole 46. Thus, the fuel pressure in the fuel supply pipe 34 is controlled according to the load of the engine E.
[0020]
Thus, during the intake stroke of the engine E, when the intake valve 15 is opened and the fuel injection valve 30 is excited and opened, the pressure-controlled fuel is injected from the valve 30 as described above. Since 31 is directed toward the downstream end of the intake port 11 opened by the intake valve 15, the intake port 11 is efficiently sucked into the fuel chamber 41 together with the intake air filtered by the air cleaner 10 and flowing down the intake passage 12. Therefore, there is little loss due to adhesion of the injected fuel 31 to the pipe wall, which can contribute to reduction in fuel consumption. In addition, the intake passage 12 connecting the air cleaner 10 and the intake port 11 is inclined backward and downward as a whole because the horn pipe 22 and the intake pipe 23 are bent at an obtuse angle. Can contribute to the improvement of the output.
[0021]
By the way, the fuel injection valve 30 is erected on the upper side wall of the bent portion of the intake pipe 23, and is arranged so that at least the upper end of the valve 30 is in front of the midpoint 32 of the outer curve at the intermediate bent portion 14c of the backbone Ff. Therefore, without changing the layout of the conventional vehicle body frame F and engine E, the fuel injection valve is provided on the upper wall of the intake passage 12 by rationally using the narrow space between the backbone Ff and the intake passage 12. 30 can be mounted, so that fuel can be injected from the valve 30 toward the intake port 11, particularly toward the downstream end, as described above.
[0022]
Further, since the fuel supply pipe 34 connected to the upper end of the fuel injection valve 30 is disposed horizontally and orthogonal to the axis of the backbone Ff, the fuel supply pipe 34 is disposed in a narrow space between the backbone Ff and the fuel injection valve 30. It can be easily arranged without being interfered by the backbone Ff.
[0023]
Next, a second embodiment of the present invention will be described with reference to FIG.
[0024]
In the second embodiment, the fuel supply pipe 34 connected to the upper end of the fuel injection valve 30 is arranged in a rearward downward slope along the lower side surface of the backbone Ff, and the backbone Ff is connected to the rear end of the fuel supply pipe 34. The configuration is the same as that of the previous embodiment except that the fuel conduit 39 arranged along the line and the regulator body 42 of the injection pressure regulator 40 are integrally connected to the front end of the fuel supply pipe 34. In the figure, parts corresponding to those of the previous embodiment are denoted by the same reference numerals, and description thereof is omitted.
[0025]
Thus, since the fuel supply pipe 34 is disposed rearwardly and downwardly along the lower side surface of the backbone Ff, the fuel supply pipe 34 is placed in a narrow space between the backbone Ff and the fuel injection valve 30 in this case as well. Can be easily arranged without being interfered by. Further, since the fuel conduit 39 connected to the rear end of the fuel supply pipe 34 is disposed along the backbone Ff, the fuel conduit 39 does not protrude greatly from the backbone Ff, and interference with other objects can be easily performed. It can be avoided.
[0026]
The present invention is not limited to the embodiments described above, and various design changes can be made without departing from the scope of the invention.
[0027]
【The invention's effect】
As described above, according to the first aspect of the present invention, the engine that causes the cylinder block and the cylinder head to protrude substantially horizontally toward the front is attached to the rear frame below the backbone, and the intake air that opens to the upper surface of the cylinder head. A throttle body having an intake passage that is connected to a port and an air cleaner attached to the front end portion of the backbone, and that is opened and closed by a throttle valve and extends obliquely downward and downward along the front half straight portion of the backbone; An intake pipe having an obtuse bend and connecting between the intake passage and the intake port; and an intake pipe portion of the intake passage and a portion of the intake passage downstream from the rotation center of the throttle valve; In the vehicle side view, a lower extension line of the boundary line of the front half straight part and the intermediate bending part, and a boundary line of the rear half straight part and the intermediate bending part It is arranged in a region sandwiched by a lower extension line, and the midpoint of the outer curve in the intermediate bending portion of the backbone is located on the front side of the upper extension surface of the mating surface of the cylinder block and the cylinder head, wherein the upper wall of the bent portion of the intake pipe, the upright fuel injection valve capable of injecting fuel downwardly into the intake port, the valve upper end portion of and valve fits into the area as viewed from the side of the vehicle Is located in front of the middle point, and a fuel supply pipe fitted to the upper end portion is opposed to and close to the lower surface of the intermediate bent portion, and fuel is supplied from the fuel injection valve toward the intake port of the cylinder head. since so as to injection, without changing the layout of a conventional vehicle body frame and the engine, reasonably utilize the narrow space between the backbone and the intake passage, the bent portion of the intake passage (in particular, the intake pipe A fuel injection valve can be attached to the upper side wall of the cylinder, and therefore fuel can be injected from the fuel injection valve toward the intake port of the cylinder head, thereby reducing loss due to fuel adhering to the pipe wall. it can.
[Brief description of the drawings]
FIG. 1 is a side view of a backbone type motorcycle showing a first embodiment of the present invention.
FIG. 2 is a side view around the engine and the intake system of the motorcycle.
FIG. 3 is an enlarged side view around a fuel injection device in the intake system of FIG. 2;
4 is a view taken in the direction of arrow 4 in FIG. 3;
FIG. 5 is a side view similar to FIG. 3, showing a second embodiment of the present invention.
[Explanation of symbols]
E ... Engine F ... Body frame Ff ... Backbone Fr ... Rear frame Y ... Backbone axis 1 ... Head pipe 2 ... Front fork 3 Rear fork 8 Cylinder block 9 Cylinder head 10 Air cleaner 11 Intake port 12 Intake passage 14a・ First half straight portion 14b ・ ・ ・ Second half straight portion 14c ・ ・ ・ Intermediate bent portion 23 ・ ・ ・ ・ ・ ・ Intake pipe 24 ・ ・ ・ ・ Throttle body 24a ・ ・ ・ Intake passage 25 ・ ・ ・ ・ Throttle valve
25a: Throttle valve rotation center 30 ... Fuel injection valve 32 ... Middle point 34 of the outer curve at the intermediate bend ... Fuel supply pipe 39 ... Fuel conduit 40 ... ..Injection pressure regulator

Claims (1)

A front half straight portion (14a) that extends downward and straight from the head pipe (1) that supports the front fork (2), and a second half that extends downward and straight downward from the front half straight portion (14a). A backbone (Ff) comprising an arcuate intermediate bent portion (14c) in a vehicle side view continuously connecting the straight portion (14b) and both straight portions (14a, 14b), and a rear end of the backbone (Ff) A vehicle body frame (F) is constituted by a rear frame (Fr) that is integrally coupled to the rear fork (3) and supports the rear fork (3). A cylinder block (8) is formed on the rear frame (Fr) below the backbone (Ff). ) And an engine (E) that causes the cylinder head (9) to protrude substantially horizontally toward the front, and an intake port (11) that opens to the upper surface of the cylinder head (9); The air cleaner (10) attached to the front end of the backbone (Ff) is connected via an intake passage (12) disposed below the backbone (Ff) and inclined substantially rearward and downward. In the backbone type motorcycle in which the throttle valve (25) is rotatably provided in the middle part of the passage (12),
The throttle body (24) having an intake passage (24a) that is opened and closed by the throttle valve (25) and is inclined downward and downward along the front half straight portion (14a) and extends linearly. And an intake pipe (23) having an obtuse bend and connecting the intake passage ( 24a) and the intake port (11), and an intake pipe (23) in the intake passage (12 ) A boundary between the front half straight portion (14a) and the intermediate bent portion (14c) between the portion and the downstream portion of the intake passage (24a) from the rotation center (25a ) of the throttle valve (25) in a vehicle side view Arranged in a region sandwiched between a lower extension line of the line and a lower extension line of the boundary line of the second half straight portion (14b) and the intermediate bent portion (14c),
The midpoint (32) of the outer curve of the intermediate bent portion (14c) of the backbone (Ff) is located in front of the upper extension surface of the mating surfaces of the cylinder block (8) and the cylinder head (9). And
Wherein the upper wall of the bent portion of the intake pipe (23), a fuel injection valve capable of injecting fuel into the downward (30) while standing on the intake port (11), the valve (30) is a vehicle side the upper end of and valve (30) fits into the area is in the front of the midpoint (32) in view, the fuel supply pipe fitted to the upper end (34) of the intermediate bent portion (14c) the lower surface faces close, characterized by being adapted to inject fuel toward the intake ports of the cylinder head (9) from the fuel injection valve (30) (11), in the backbone-type motorcycle Fuel injection device.

Images