JP3967412B2 - Vaporizer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vaporizer having a power jet.
[0002]
[Prior art]
In engines for vehicles or industrial machines, a power jet is provided in addition to a main jet as means for obtaining high output and high torque by a carburetor. This power jet opens a fuel outlet hole connected to a fuel chamber via a fuel passage to a venturi section, and when the intake negative pressure of the venturi section exceeds a predetermined value, the fuel is sucked and sucked by the negative pressure. It is comprised so that a fuel may flow out from a fuel blowing hole. Documents disclosing the prior art of such a power jet include Japanese Utility Model Publication Nos. 49-3847, 49-46325, and 1-277669.
[0003]
[Problems to be solved by the invention]
However, in a conventional carburetor with a power jet, the fuel jet fuel outlet is located at a relatively high position in the venturi (inside the intake passage), and the fuel is discharged with the average head pressure of the venturi. Because of the suction, in the region of low engine speed and low opening, the negative pressure (suction force) acting on the fuel outlet is too small to cause the fuel to flow out, and the power jet effect of improving the output and torque is sufficient. There is a problem that it cannot be obtained.
[0004]
The present invention has been made in view of such technical problems, and an object of the present invention is to discharge fuel from a power jet even in a region where the negative pressure value is extremely low to low opening and extremely low to low rotation. As a result, there is no mottling or breathing when the engine is fully open at low speed, and the output and torque are improved over a wide rotational speed range from extremely low opening, extremely low rotation to over-rotation (overrun). It is possible to provide a vaporizer capable of forming a wide power band.
[0005]
[Means for Solving the Problems]
The invention of claim 1, in order to achieve the above object, a fuel outlet hole which is connected to the fuel chamber via a fuel passage is opened to the venturi section of the intake passage, sucks the more fuel into the intake negative pressure of the venturi section and, in a vaporizer having a power jet allowed to flow out of the fuel into the venturi section from the fuel outlet hole, is also provided with a slidable piston valve across the venturi portion in the vertical direction, the lower surface of the piston valve in the intake passage A rectifying guide composed of two ribs parallel to the intake flow is provided on the upstream side of the intake flow, and the fuel outlet hole is located near the intake flow downstream side of the rectification guide in the intake passage and on the lower surface of the venturi section Oite in central, it is opened to the lower space of the cutaway formed in the lower end surface of the piston valve in a substantially fully closed position, the cutaway Ri in the region intake negative pressure of the venturi section is smaller by the effect, characterized in that to allow outflow of fuel from the power jet.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a left side view illustrating a motorcycle equipped with a vaporizer to which the present invention is applied. In FIG. 1, a vehicle body frame 10 includes a head pipe 11, left and right main upper members 12 extending rearward from the head pipe 11, left and right main lower members 13 extending downward from the head pipe 11, and the main upper A center bracket 14 to which the rear ends of the member 12 and the main lower member 13 are connected, left and right seat rails 15 extending rearward from the middle of each of the left and right main upper members 12, the center bracket 14 and the seat rail 15 The left and right rear support members 16 are connected to each other, and the cross members (not shown) are connected to appropriate portions of the left and right members.
[0009]
A front wheel 18 is pivotally supported by a front fork 17 that is mounted on the head pipe 11 so as to be turnable (steerable) in the left-right direction. Further, a rear wheel 21 is pivotally supported at a front end portion (rear end portion) of a rear fork 20 that is pivotally supported so as to swing in the vertical direction around the pivot shaft 19 of the center bracket 14. A rear wheel load carrying cushion unit 22 is mounted between the rear fork 20 and the vehicle body frame 10. A fuel tank 23 and a seat 24 are attached to the main upper member 12 and the seat rail 15 from the front.
[0010]
An engine 25 is mounted between the left and right main upper members 12 and the left and right main lower members 13. A carburetor 26 is connected to the intake passage (intake pipe) of the engine 25. The carburetor 26 uses an engine negative pressure to mix fuel with intake air taken in through an air cleaner or the like to generate an appropriate air-fuel mixture. An exhaust pipe 28 is connected to the exhaust port of the engine 25, and exhaust from the combustion chamber is discharged to the outside through the exhaust pipe 28. In the illustrated motorcycle, a cowling 27 that covers the front half of the left and right side surfaces from the front end of the body frame 10 is mounted. The vaporizer 26 has a configuration to which the present invention is applied.
[0011]
2 is a partially cutaway side view of an embodiment of a vaporizer to which the present invention is applied, FIG. 3 is a front view as seen from line 3-3 (suction side) in FIG. 2, and FIG. 4 is a partial cross-sectional plan view as seen from line 4-4 in FIG. 2 to 4, an intake passage 31 penetrating the carburetor main body 30 is formed, and air flowing in the direction of arrow A from an air cleaner (not shown) passes through the intake passage 31 to the left engine (not shown). ) Is inhaled. On the other hand, a fuel chamber (float chamber) 32 for storing liquid fuel such as gasoline is formed below the intake passage 31. The oil level of the fuel in the float chamber 32 is always determined by the float 34 that can swing up and down around the fulcrum 33 and the fuel supply needle valve 35 that is controlled to open and close by the vertical movement of the float 34. Maintained within the proper range.
[0012]
Therefore, between the venturi section 36 of the intake passage 31 and the fuel chamber (float chamber) 32, a main system 37 for mainly controlling the fuel supply amount (air-fuel ratio) during the output operation and idling are included. A slow system 38 for controlling the fuel supply amount (air-fuel ratio) during extremely low speed and low speed operation is provided.
[0013]
The fuel passage of the main system 37 includes a main nozzle 39 that communicates with the fuel outlet 46 of the venturi section 36 of the intake passage 31 and a main jet 40 that is mounted below the main nozzle 39 (a position that opens below the fuel oil level). It is configured. A piston valve (slide piston) 41 slidable across the venturi portion 36 of the intake passage 31 is provided at a position corresponding to the main nozzle 39, and the slide piston 41 is provided in the main nozzle 39. A jet needle 42 to be inserted is attached. The jet needle 42 has a tapered shape, and the insertion depth of the jet needle 42 is changed in accordance with the movement of the slide piston 41, so that the fuel outlet 46 of the main nozzle 39 opened in the venturi portion 36 is changed. It is comprised so that an area may be adjusted. The fuel atomizing air in the main nozzle 39 is introduced from the air intake port 48 into the main nozzle 39 through the main air jet 49 for measurement.
[0014]
The piston valve (slide piston) 41 is always urged downward by a return spring 47. A cap 43 is attached to the top of the vaporizer body 30, and the inside of the vaporizer body 30 is covered by the cap 43. The operation of the slide piston 41 is performed by the driver via the operation cable 44. That is, on the carburetor side of the operation cable 44, the inner is connected to the slide piston 41 and the outer is held by the cap 43. The other end of the operation cable 44 is normally connected to a throttle lever (not shown) mounted on the steering handle. The driver adjusts the vertical position of the piston valve 41 via the operation cable 44 by the throttle lever, and controls the opening degree of the piston valve 41 (opening degree of the venturi portion 36).
[0015]
The fuel passage of the slow system 38 includes a fuel-measuring slow jet 50 that opens below the fuel oil level in the fuel chamber (float chamber) 32, a slow nozzle 51 for atomizing the fuel, and a fuel passage for the atomized fuel. (Not shown) and a plurality of small fuel outlet holes (not shown) that open to the intake passage 31. The fuel outlet hole is formed in the vicinity of the upstream side of the intake air flow from directly below the throttle valve (not shown) formed of a butterfly valve disposed on the downstream side of the intake air flow with respect to the piston valve 41. The fuel atomizing air in the slow nozzle 51 is introduced into the slow nozzle 51 through a slow air jet (not shown) for measurement from a slow air intake (not shown).
[0016]
The vaporizer described above is provided with a power jet 60. FIG. 5 is a cross-sectional view showing the overall configuration of the power jet 60. 2 to 5, the power jet 60 opens a fuel outlet hole 62 connected to the fuel chamber 32 through a fuel passage 61 to the venturi portion 36, and the intake negative pressure of the venturi portion 36 is a predetermined value or more. Then, the fuel is sucked by the negative pressure, and the sucked fuel is made to flow out from the fuel blowing hole 62. And in this invention, it is comprised so that the said fuel blowing hole 62 may be arrange | positioned in the range which the throttle effect by the lower end surface of the piston valve 41 generate | occur | produces. On the lower end surface of the piston valve 41, a cutter way (CUT AWAY) 52 that is normally inclined upward toward the upstream side of the intake air flow is formed. In this case, the fuel outlet hole 62 is formed by the cutter way 52. It is arranged within a range where the throttle effect of intake air is generated.
[0017]
In the power jet 60 shown in FIG. 5, a fuel outlet 63 is formed below the oil level of the fuel chamber (float chamber) 32, and a fuel introduction path 64 is formed in the carburetor body 30. The fuel introduction path 64 is connected by a fuel pipe 65. Further, in the carburetor main body 30, an intermediate chamber 66 communicating with the other end of the fuel introduction passage 64 and a fuel supply passage 67 communicating from the intermediate chamber 66 to the lower part of the venturi portion 36 of the intake passage 31 are formed. Has been. A pipe-shaped nozzle 68 is fixed to the outlet of the fuel supply passage 67 by press fitting or the like. The fuel blowing hole 62 is formed in the vicinity of the tip of the nozzle 68. Further, a jet 69 for regulating the fuel flow rate is mounted in the middle of the fuel introduction path 64.
[0018]
Thus, the fuel passage 61 that leads from the fuel chamber 32 to the fuel outlet 62, that is, the fuel outlet 63 of the fuel chamber 32, the fuel pipe 65, the fuel introduction path 64, the intermediate chamber 66, the fuel feed port. A fuel passage 61 including a supply passage 67 and the nozzle 68 is formed. Therefore, the fuel blowing hole 62 is disposed within a range where a throttling effect is generated by the lower end surface (cutaway 52) of the piston valve 41. In other words, the nozzle 68 has a shape and a size such that the fuel blowing hole 62 is disposed within a range where the throttle effect is generated by the lower end surface (cutaway 52) of the piston valve 41.
[0019]
The range in which the throttling effect occurs in this case is as much as possible as shown by the two-dot chain line B from the lower space of the lower end surface (cutaway) of the piston valve 41 in the substantially fully closed position in the side view of FIG. Corresponds to the lower area. Further, within the range where the diaphragm effect occurs, in the front view of FIG. 3 and the plan view of FIG. 4, a central region including the center position of the venturi portion 36 (for example, centering on the center of the venturi portion 36 as shown in the figure). In other words, it corresponds to a portion where a substantial negative pressure is generated even at an extremely low to low opening and rotation speed of the engine. The fuel outlet hole (opening formed in the tip of the nozzle 68 in this embodiment) 62 is opened toward the downstream side of the intake air flow in order to reduce or eliminate the influence of the dynamic pressure of the intake air flow.
[0020]
In FIG. 5, when the engine reaches the set over-rotation region, the fuel passage 61 is shut off at a position above the intermediate chamber 66 of the carburetor body 30 (the power jet 60 is turned off). On-off valve 70 is attached. In the illustrated example, the on-off valve 70 is disposed so as to open and close the fuel passage 61 at the outlet opening of the fuel introduction path 64 (opening to the intermediate chamber 66). Further, the on-off valve 70 of the present embodiment is configured by an electromagnetic valve (solenoid valve), and is electrically controlled to open / close by the control unit 72 based on the engine speed detected by the speed sensor 71. The control of the power jet 60 is executed in such a manner that the on-off valve 70 is closed and the power jet 60 is turned off in an overspeed region of the engine 25 (for example, a rotational speed region exceeding the maximum output rotational speed). .
[0021]
The on-off valve (solenoid valve) 70 controls the position in the axial direction of the core member having the valve body 74 at the tip by controlling the energization to the exciting coil 73 by the control unit 72. Thus, the fuel passage 61 (fuel introduction passage 64) is opened and closed. In the carburetor 26 shown in FIGS. 2 to 5, a rectifying guide 53 including two ribs parallel to the flow direction is formed in the lower portion of the intake passage 31 on the upstream side of the piston valve 41. . Accordingly, the positions of the fuel outlets 62 of the power jet 60 are, for example, X (below the cutaway), Y (between the left and right rectifying guides 53), and Z (the center slightly above the rectifying guides 53) in FIG. Part) etc. can be selected.
[0022]
According to the embodiment described above, the fuel outlet hole 62 connected to the fuel chamber 32 via the fuel passage 61 is opened in the venturi portion 36, and the negative pressure is increased when the intake negative pressure in the venturi portion exceeds a predetermined value. In the carburetor 26 having the power jet 60 for sucking the fuel and discharging the sucked fuel from the fuel blowing hole 62, the fuel blowing hole 62 is within the range B in which the throttling effect by the lower end surface 52 of the piston valve 41 is generated. Since it is configured to be disposed, the fuel outlet 62 is disposed at a position where a substantial negative pressure is generated even at extremely low to low opening and extremely low to low rotation, and therefore extremely low to low. The fuel can be discharged from the power jet 60 even under operating conditions with a small negative pressure value in the opening degree and extremely low to low rotation, and thereby, the motetsu when the engine 25 is fully opened at a low speed. The carburetor 26 that can improve the output and torque over a wide rotational speed range from extremely low opening, extremely low rotation to over-rotation (overrun), and can form a wide power band while eliminating breathing Obtainable.
[0023]
Further, an on-off valve (solenoid valve or the like) 70 is provided in the middle of the fuel passage 61. In an over-rotation region exceeding the maximum output rotation speed of the engine 25, this is detected by the rotation speed sensor 71 and the control unit 72 Since the on / off valve 70 is closed and the power jet 60 is controlled to be turned off, it is possible to prevent a decrease in output due to the excessively rich air-fuel mixture in the over-rotation region, and to obtain a high output and high torque. It becomes possible to further expand the width of the power band.
[0024]
FIG. 6 shows the rotational speed characteristics of the output for the same engine when using a carburetor without a power jet (curve P) and when using a carburetor with a power jet according to the present invention (curve Q). It is a graph to illustrate. As is apparent from the graph of FIG. 6, by implementing the present invention, a carburetor capable of improving the output in the entire rotational speed region from the extremely low speed to the excessive speed is obtained.
[0025]
FIG. 7 is a longitudinal sectional view showing a main part configuration of another embodiment of a vaporizer with a power jet to which the present invention is applied, and FIG. 8 is a main part configuration of another part of the vaporizer with a power jet of FIG. FIG. 2 to 5, the fuel outlet 62 of the power jet 60 is fixedly disposed at a predetermined position in the venturi 36 (in a range B in which the throttle effect is generated by the piston valve 41). In the embodiment of FIG. 8, the fuel outlet 62 is attached to a lower end surface of the piston valve 41 (in the illustrated example, a cutaway 52 formed on the lower end surface, and is mounted so as to move up and down together with the piston valve. .
[0026]
In FIG. 7, the nozzle 68 having the fuel blowing hole 62 is fixedly attached, for example, by being press-fitted into a hole formed in the lower end surface (cutaway surface in the illustrated example) 52 of the piston valve 41. The protruding height of the nozzle 68 from the lower end surface 52 of the piston valve 41 is selected so as not to interfere with the wall surface of the venturi portion when the piston valve 41 is fully closed. The fuel blowing hole (opening formed at the tip of the nozzle 68) 62 is opened toward the downstream side of the intake air flow in order to reduce or eliminate the influence of the dynamic pressure of the intake air flow.
[0027]
A hollow pipe-like nipple 81 is fixed to the upper end of the piston valve 41, and the nipple 81 is connected to the nozzle 68 (and thus the above-mentioned) through a communication passage 85 such as a hole or a tube formed in the piston valve 41. The fuel outlet 62 also communicates with the inner open end. In addition, a hollow pipe-shaped nipple 82 having one end (upper end in the drawing) protruding into the upper space 84 and opening is fixed at a predetermined position on the upper portion of the vaporizer body 30, and the protruding end (upper end in the drawing) of the nipple 82 is fixed. ) And the other end (upper end) of the nipple 81 are connected by a flexible tube 83. The flexible tube 83 is sufficiently long to absorb the movement of the piston valve 41 (and hence the movement of the nipple 81). For example, a long tube is spirally stored in the upper space 84 of the vaporizer body 30. ing.
[0028]
In FIG. 8, a fuel outlet 63 is formed below the oil level in the fuel chamber (float chamber) 32, a fuel introduction path 64 is formed in the carburetor body 30, and the fuel outlet 63 and the fuel introduction path 64 are formed. Are connected by a fuel pipe 65. Further, an intermediate chamber 66 communicating with the other end of the fuel introduction path 64 and a fuel feed path 86 extending from the intermediate chamber 66 are formed in the carburetor body 30. Further, a jet 69 for regulating the fuel flow rate is mounted in the middle of the fuel introduction path 64. Therefore, the other end (lower end in the figure) of the nipple 82 opening in the upper space 84 shown in FIG. 7 and the other end of the fuel feed path 86 shown in FIG. Communicating with each other by a communication path (for example, an extension of the fuel supply path 86 is also possible).
[0029]
Thus, the fuel passage 61 that leads from the fuel chamber 32 to the fuel outlet 62, that is, the fuel outlet 63 of the fuel chamber 32, the fuel pipe 65, the fuel introduction path 64, the intermediate chamber 66, the fuel feed A fuel passage 61 including a passage 86, a communication passage (not shown) from the fuel supply passage to the nipple 82, the flexible tube 83, a communication passage 85 in the piston valve 41, and the nozzle 68 is formed. .
[0030]
In FIG. 8, also in the present embodiment, when the engine reaches an over-rotation region set in the upper position of the intermediate chamber 66 of the carburetor body 30, this is detected and the fuel passage 61 is shut off (power) An on-off valve 70 for turning off the jet 60 is attached. In the illustrated example, the on-off valve 70 is disposed so as to open and close the fuel passage 61 at the outlet opening of the fuel introduction path 64 (opening to the intermediate chamber 66). Further, the on-off valve 70 of the present embodiment is configured by an electromagnetic valve (solenoid valve), and is electrically controlled to open / close by the control unit 72 based on the engine speed detected by the speed sensor 71. The control of the power jet 60 is executed in such a manner that the on-off valve 70 is closed and the power jet 60 is turned off in an overspeed region of the engine 25 (for example, a rotational speed region exceeding the maximum output rotational speed). .
[0031]
The on-off valve (solenoid valve) 70 controls the position in the axial direction of the core member having the valve body 74 at the tip by controlling the energization to the exciting coil 73 by the control unit 72. Thus, the fuel passage 61 (fuel introduction passage 64) is opened and closed. Also in this embodiment, a rectifying guide 53 composed of two ribs parallel to the flow direction is formed in the lower portion of the intake passage 31 on the upstream side of the intake air flow of the piston valve 41.
[0032]
According to the embodiment described above, the nozzle 68 connected to the fuel chamber 32 through the fuel passage 61 is fixed to the lower end surface of the piston valve 41, and the fuel outlet hole 62 formed in the nozzle is formed under the piston valve 41. It opens toward the intake downstream side below the end face (for example, the cutter way 52), and when the intake negative pressure (Venturi negative pressure) below the lower end face exceeds a certain value, the negative pressure causes the fuel to be sucked. Since the suctioned fuel is configured to flow out from the fuel blowing hole 62 to the venturi section 36, a sufficient and stable negative pressure is generated in the fuel blowing hole 62 even at extremely low to low opening and extremely low to low rotation. Therefore, an appropriate amount of fuel can be stably discharged from the power jet 60 even under extremely low to low opening and extremely low to low rotation operating conditions, and the engine 25 can be fully opened. Low It is possible to eliminate the sluggish and with a breath in time. In addition, the output and torque can be improved over a wide rotational speed range from extremely low opening, extremely low rotation to over-rotation (overrun), and the carburetor 26 capable of forming a wide power band can be obtained.
[0033]
Also in this embodiment, an on-off valve (solenoid valve or the like) 70 is provided in the middle of the fuel passage 61, and this is detected by the rotational speed sensor 71 in an overspeed region exceeding the maximum output rotational speed of the engine 25. Since the control unit 72 controls to close the on-off valve 70 and turn off the power jet 60, as in the case of the embodiment of FIGS. Thus, it is possible to further expand the width of the power band, which is the rotation speed region where high output and high torque can be obtained. Therefore, according to the present embodiment, as shown by the curve Q in FIG. 6, a carburetor capable of improving the output in the entire rotational speed region from the extremely low speed to the excessive speed is obtained.
[0034]
【The invention's effect】
As apparent from the above description, according to the invention of claim 1, a fuel outlet hole which is connected to the fuel chamber via a fuel passage is opened to the venturi section of the intake passage, and more intake negative pressure of the venturi section In the carburetor having a power jet that sucks the fuel and causes the fuel to flow out from the fuel blowing hole to the venturi part, a piston valve that can slide across the venturi part in the vertical direction is provided, and a lower surface of the intake passage is provided . A rectifying guide composed of two ribs parallel to the intake flow is provided on the upstream side of the intake air flow from the piston valve, and the fuel blowing hole is located in the vicinity of the intake flow downstream side of the rectification guide in the intake passage and the venturi Oite the central portion of the lower surface of parts, is opened to the lower space of the cutaway formed in the lower end surface of the piston valve in a substantially fully closed position, the Ca Since the intake negative pressure of the venturi section by throttling effect of Tawei in a small area it has a configuration that allows flow out of the fuel from the power jet, ultra-low-low opening, a small negative pressure in the ultra-low-low rotation region However, the fuel can flow out from the power jet, and the head difference between the fuel outlet hole and the oil level in the fuel chamber can be reduced to make it easier to discharge the fuel at low speeds. A carburetor that eliminates mottling and breathing, can improve output and torque over a wide range of rotational speeds from extremely low opening, extremely low rotation to over rotation (overrun), and can form a wide power band Provided.
[0036]
According to a second aspect of the invention, in addition to the configuration of the first aspect, an on-off valve is provided in the middle of the fuel passage, which is detected in an over-rotation region of the engine, and the on-off valve is closed to close the power jet. In addition to the above-described effect, the carburetor can further reduce the output due to the excessively rich mixture in the over-rotation region and further expand the width of the power band.
[Brief description of the drawings]
FIG. 1 is a left side view illustrating a motorcycle equipped with a vaporizer to which the present invention is applied.
FIG. 2 is a partially cutaway side view of an embodiment of a vaporizer to which the present invention is applied.
FIG. 3 is a front view as seen from line 3-3 in FIG. 2;
4 is a partial cross-sectional plan view taken along line 4-4 in FIG. 2;
FIG. 5 is a cross-sectional view showing the overall configuration of the power jet.
FIG. 6 is a graph illustrating a comparative example of output characteristics of a vaporizer without a power jet and a vaporizer with a power jet according to the present invention.
FIG. 7 is a longitudinal sectional view showing the configuration of the main part of another embodiment of a vaporizer with a power jet to which the present invention is applied.
8 is a cross-sectional view showing a main part configuration of another part of the power jet carburetor of FIG. 7; FIG.
[Explanation of symbols]
25 Engine 26 Vaporizer 30 Vaporizer body 31 Intake passage 32 Fuel chamber (float chamber)
36 Venturi section 37 Main system 38 Slow system 40 Main jet 41 Piston valve 50 Slow jet 52 Cutaway 53 Flow guide 60 Power jet 61 Fuel passage 62 Fuel outlet hole 68 Nozzle 69 Jet 70 On-off valve (solenoid valve)
71 Rotational speed sensor 72 Control unit 83 Flexible tube 84 Upper space

Claims (2)

The fuel outlet hole which is connected to the fuel chamber via a fuel passage is opened to the venturi section of the intake passage, it sucks the more fuel into the intake negative pressure of the venturi section, the outflow of fuel into the venturi section from the fuel outlet hole In a vaporizer with a power jet
Provided with also slidable piston valve across the venturi portion in the vertical direction, provided with a rectifying guide consisting of two parallel ribs in the intake air flow to the intake flow upstream section than the piston valve of the lower surface of the intake passage,
Wherein the fuel outlet hole, Oite the central portion of the lower surface of the venturi section a suction flow downstream vicinity of the rectifying guides of the intake passage, substantially cutaway formed in the lower end surface of the piston valve in the fully closed position Open in the space below,
A carburetor characterized in that fuel can flow out from the power jet even in a region where the intake negative pressure in the venturi section is small due to the throttling effect of the cutaway .   2. The carburetor according to claim 1, wherein an on-off valve is provided in the middle of the fuel passage, and this is detected in an over-rotation region of the engine, and the on-off valve is closed to turn off the power jet.

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