JP3718930B2 - Sliding throttle valve type vaporizer - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a carburetor that adjusts and controls the amount and concentration of an air-fuel mixture supplied to an engine, and in particular, a carburetor body whose intake passage is controlled to open and close by a sliding throttle valve;
A buoyancy chamber body that cooperates with the carburetor body to form a buoyancy chamber that maintains a constant fuel liquid level therein;
One end opens into the intake passage through the needle jet,
A main fuel control system in which the other end is opened into the float chamber through the main fuel jet and a jet needle integrally attached to the sliding throttle valve is inserted into the needle jet;
One end opens into the intake passage through the low-speed nozzle,
A low speed fuel control system whose other end opens into the float chamber via a low speed fuel jet;
The present invention relates to a sliding throttle valve type carburetor equipped with
[0002]
[Prior art]
A conventional sliding throttle valve type carburetor is shown in FIGS.
FIG. 11 is a longitudinal sectional view of a sliding throttle valve type vaporizer, and FIG. 12 is a transverse sectional view of only the vaporizer body taken along the line P-P in the figure.
Reference numeral 1 denotes a carburetor body that is formed by penetrating an intake passage 2 laterally inside, and the intake passage 2 is opened and closed by a sliding throttle valve 3 operated by a driver.
The sliding throttle valve 3 is movably disposed in a throttle valve guide cylinder 2B connected to the intake passage 2.
The lower concave portion of the vaporizer main body 1 and the floating chamber main body 4 covering the lower concave portion are arranged so as to face each other, and are fastened by screwing with screws to form the floating chamber 5.
An annular seal member is disposed between the both contact surfaces.
Further, in the float chamber 5, the valve seat 7 connected to the fuel passage 6, the valve 8 that opens and closes the valve seat 7, and the float 9 that operates the valve 8 by the change of the fuel liquid level in the float chamber 5 are constant. A fuel level is formed.
[0003]
M is a main fuel control system and includes the following.
A main fuel boss 10 is erected from the carburetor body 1 toward the bottom of the float chamber 5. Inside the main fuel boss 10, a needle jet 11 is disposed at an upper portion thereof, and a main fuel boss is disposed at a lower portion thereof. The jet 12 is screwed.
The needle jet 11 is disposed so as to face the bottom portion 2 </ b> A of the intake passage 2 and is disposed on the longitudinal axis XX of the intake passage 2. This is best shown in FIG. The main fuel jet 12 is disposed facing the bottom of the float chamber 5.
That is, the main fuel jet 12 is screwed to the lower end of the main fuel boss 10.
On the other hand, a jet needle 13 is integrally attached to the sliding throttle valve 3, and at least the jet needle 13 is inserted into the needle jet 11. As described above, the fuel in the float chamber 5 is sucked out to the bottom portion 2A of the intake passage 2 through the main fuel jet 12, the gap between the jet needle 13 and the needle jet 11.
[0004]
S is a low-speed fuel control system and consists of the following.
Reference numeral 14 denotes a low-speed fuel boss disposed close to the main fuel boss 10 from the carburetor main body 1 toward the bottom of the float chamber 5, and a low-speed fuel jet 15 is screwed to a lower portion of the low-speed fuel boss 14. .
That is, the low-speed fuel jet 15 is arranged facing the bottom of the float chamber 5.
A low-speed air-fuel mixture passage 16 connected to the low-speed fuel jet 15 opens into the intake passage 2 via a bypass hole 17 corresponding to the sliding throttle valve 3 and from the sliding throttle valve 3 via a pilot outlet hole 18. It opens to the engine side intake passage 2C (in other words, downstream of the sliding throttle valve 3).
More specifically,
The bypass hole 17 faces the engine-side bottom surface 3 </ b> A of the sliding throttle valve 3 and opens to the bottom 2 </ b> A of the intake passage 2 and opens on the longitudinal axis XX of the intake passage 2.
This is best shown in FIG.
[0005]
[Problems to be solved by the invention]
The amount of fuel supplied to the engine from the sliding throttle valve type carburetor is determined by the sum of the main fuel supplied from the main fuel control system M and the low speed fuel supplied from the low speed fuel control system S. The
When the sliding throttle valve 3 is in the low opening state, the share of the amount of fuel supplied from the low speed fuel control system S composed of the bypass hole 17 and the pilot outlet hole 18 is large. The share of the fuel supply amount from the main fuel control system M composed of the needle jet 11 is small, so that a relatively small fuel amount A (L / H) suitable for the low opening state is controlled and supplied. .
For example, in the small fuel amount A (L / H), the fuel sharing rate of the main fuel control system M is 10%, and the fuel sharing rate of the low speed fuel control system S is 90%.
[0006]
When the sliding throttle valve 3 is in the middle opening state, the share of the amount of fuel supplied from the low speed fuel control system S including the bypass hole 17 and the pilot outlet hole 18 is medium. The fuel supply amount sharing ratio from the main fuel control system M composed of the needle jet 11 is medium, so that a relatively medium fuel amount B (L / H) suitable for the medium opening state is controlled and supplied. .
For example, of the medium fuel amount B (L / H), the fuel sharing rate of the main fuel control system M is 60%, and the fuel sharing rate of the low speed fuel control system S is 40%.
[0007]
Further, when the sliding throttle valve 3 is in a high opening state, the share of the amount of fuel supplied from the low speed fuel control system S composed of the bypass hole 17 and the pilot outlet hole 18 is extremely small, and the jet needle 13 The share of the fuel supply amount from the main fuel control system M comprising the needle jet 11 is large, so that a relatively large fuel amount C (L / H) suitable for the high opening state is controlled and supplied. The
For example, in the large fuel amount C (L / H), the fuel sharing rate of the main fuel control system M is 90%, and the fuel sharing rate of the low speed fuel control system S is 10%.
[0008]
On the other hand, according to the experiment result of the present inventor, particularly in the low opening state of the sliding throttle valve 3, the share of fuel supply from the low speed fuel control system S including the bypass hole 17 and the pilot outlet hole 18 is increased. As a result, it was confirmed that the responsiveness and the torque feeling during the engine acceleration operation were improved.
Furthermore, it has been confirmed that the linear characteristics of the engine are improved when the sliding throttle valve 3 is opened from the low opening state.
[0009]
Here, in the conventional sliding throttle type carburetor, in order to increase the share of fuel supply from the low speed fuel control system S, the fuel from the low speed fuel control system S including the bypass hole 17 and the pilot outlet hole 18 is used. Although it is considered that the supply amount is increased, according to this, the fuel flow rate is lower than the fuel flow rate of A (L / H) adapted to the low opening state of the sliding throttle valve 3, and the fuel flow rate is low. Therefore, the response and torque feeling during the engine acceleration operation cannot be improved, and further, the linear characteristics cannot be improved.
Also, the share of the low-speed fuel control system S can be reduced by bringing the opening position of the bypass hole 17 closer to the opening of the needle jet 11 (in other words, by moving the sliding throttle valve 3 upstream from the engine-side bottom surface 3A). Although it was confirmed that the main fuel boss 10 of the main fuel control system M and the low speed fuel boss 14 of the low speed fuel control system S are close to each other, they could not be used practically.
[0010]
The sliding throttle valve type carburetor according to the present invention is made in view of such a problem, and particularly increases the share of the fuel supply of the low speed fuel control system S in the low opening state of the sliding throttle valve 3. Therefore, the main purpose is to improve the response and torque feeling during acceleration operation and further improve the linear characteristics.
[0011]
[Means for solving the problems]
In order to achieve the above object, the sliding throttle valve type carburetor according to the present invention is a vaporization in which the intake passage is controlled to open and close by a sliding throttle valve arranged in a throttle valve guide cylinder connected to the intake passage. The vessel body;
A buoyancy chamber body that cooperates with the carburetor body to form a buoyancy chamber that maintains a constant fuel liquid level therein;
One end opens to the bottom of the intake passage through the needle jet,
A main fuel control system in which the other end is opened into the float chamber through the main fuel jet and a jet needle integrally attached to the sliding throttle valve is inserted into the needle jet;
A low-speed fuel control system having one end opened through a bypass hole at the bottom of the intake passage facing the engine-side bottom surface of the sliding throttle valve and the other end opened into the float chamber through a low-speed fuel jet;
In the sliding throttle valve type carburetor with
At the bottom of the intake passage between the opening to the intake passage of the needle jet and the opening to the intake passage of the bypass hole,
Providing a control projection protruding into the intake passage;
The control protrusion,
A pair of side surface portions that are on the needle jet hole side, have a symmetrical shape with respect to the longitudinal axis from the upstream top located on the longitudinal axis of the intake passage, and go downstream
The first feature is that it is formed by a downstream side surface portion that is on the bypass hole side and that crosses the longitudinal axis of the intake passage and has both ends thereof connected to the pair of side surface portions.
[0012]
In addition to the first feature, the present invention has a second feature in that the control protrusion has a triangular pyramid shape.
[0013]
In addition to the first feature, the third feature of the present invention is that the control protrusion has a triangular prism shape.
[0014]
In addition to the first feature described above, the present invention has a fourth feature that the control projection has a semi-cylindrical shape.
[0015]
Furthermore, the present invention has a fifth feature that, in addition to the first feature, the control protrusion has a cylindrical shape.
[0016]
【Example】
An embodiment of the sliding throttle valve type carburetor according to the present invention will be described below with reference to FIGS.
Only the parts different from FIGS. 11 and 12 showing the conventional sliding throttle valve type carburetor will be described, and the same structural parts are denoted by the same reference numerals and the description thereof will be omitted.
The needle jet 11 constituting the main fuel control system M is on the longitudinal axis XX of the intake passage 2 and opens to the bottom 2A of the intake passage 2.
The bypass hole 17 constituting the low-speed fuel control system S is on the longitudinal axis XX of the intake passage 2 and opens to the bottom 2A of the intake passage 2, and further to the engine-side bottom surface 3A of the sliding throttle valve 3. Open to face.
In other words, the bypass hole 17 and the needle jet 11 are on the longitudinal axis XX of the intake passage 2 and open to the bottom 2A of the intake passage 2, and the bypass hole 17 is located on the downstream side D of the needle jet 11. To do.
Here, the downstream side D refers to the left side in the figure, and refers to the side connected to the engine (not shown). On the other hand, the upstream side E refers to the right side in the figure and refers to the side connected to an air cleaner (not shown).
[0017]
Then, in the bottom 2E of the intake passage 2 between the opening of the needle jet 11 to the intake passage 2 and the opening of the bypass hole 17 to the intake passage 2, the inside of the intake passage 2 from the bottom 2E (in FIG. 1) A control projection 20 projecting upward) is provided.
[0018]
This control protrusion 20 is shown in FIG. 3, FIG. 4, and FIG.
These drawings show only the control protrusion 20 formed to protrude from the bottom 2E of the intake passage 2, FIG. 3 is a perspective view of the control protrusion 20, FIG. 4 is a top plan view, and FIG. 5 is a side view. .
The control protrusion 20 has a triangular pyramid shape,
An upstream apex 20A having a height H is formed at the upstream E thereof, which is disposed along the longitudinal axis XX of the intake passage 2. A pair of side surface portions 20B, 20C is formed from the upstream top portion 20A toward the downstream D side, and the pair of side surface portions 20B, 20C is a longitudinal axis XX passing through the upstream top portion 20A. A symmetrical shape with a gap between them.
Further, a downstream side surface portion 20D is formed on the longitudinal axis XX and downstream of the longitudinal axis XX. The downstream side surface portion 20D is formed above the upstream top portion 20A. It is continuous with the end 20E and formed with a pair of side portions 20B and 20C.
[0019]
As described above, the control projection 20 having a triangular pyramid shape is formed on the bottom 2E of the intake passage 2 between the opening of the needle jet 11 to the intake passage 2 and the opening of the bypass hole 17 to the intake passage 2. Protrusively arranged.
And according to this, the upstream top 20A of the control projection 20 is disposed facing the opening of the needle jet 11, the downstream side surface 20D is disposed facing the bypass hole 17, and the side surfaces 20B and 20C are The intake passage 2 is arranged symmetrically on the side of the longitudinal axis XX of the intake passage 2.
This state is well shown in FIGS.
[0020]
According to the sliding throttle valve type carburetor of the present invention having the above structure, in the low opening range of the sliding throttle valve 3,
FIG. 6 shows the experimental result of the rate of change of the negative pressure applied to the opening of the needle jet 11 with respect to the negative pressure applied to the intake passage 2C.
In FIG. 6, the horizontal axis indicates the negative pressure (PBmmHg) applied to the engine side intake passage 2C from the sliding throttle valve 3, and the vertical axis indicates the needle jet of a conventional sliding throttle valve type carburetor. The change rate% of the negative pressure applied to the needle jet of the sliding throttle valve type carburetor of the present invention with respect to the negative pressure applied as the reference value zero is shown.
[0021]
From the experimental results shown in FIG.
When 1 mm of the sliding throttle valve 3 is opened (indicated by − · −), when a negative pressure of 50 mmHg is applied to the intake passage 2 </ b> C, the negative pressure applied to the needle jet 11 is vaporized by the conventional sliding throttle valve type. It can be seen that there was a 43.6% reduction compared to the negative pressure applied to the needle jet 11 of the vessel. (Here, the negative pressure decreases means that the absolute value of the negative pressure decreases and approaches the atmospheric pressure)
In addition, when 1/16 of the sliding throttle valve 3 is opened (indicated by ---), when a negative pressure of 50 mmHg is applied to the intake passage 2C, the negative pressure applied to the needle jet 11 is It can be seen that the pressure is 34.2% lower than the negative pressure applied to the needle jet 11 of the conventional sliding throttle type carburetor.
Further, when 1/8 of the sliding throttle valve 3 is opened (indicated by ---), when a negative pressure of 50 mmHg is applied to the intake passage 2C, the negative pressure applied to the needle jet 11 is It can be understood that the pressure was reduced by 27.3% compared to the negative pressure applied to the needle jet 11 of the conventional sliding throttle valve type carburetor.
That is, from the above experimental results, the negative pressure applied to the needle jet 11 is compared with the negative pressure applied to the needle jet 11 of the conventional sliding throttle valve type carburetor in the low opening range of the sliding throttle valve 3. It is understood that it could be reduced.
[0022]
On the other hand, the amount of fuel required by the engine is the same whether it is in the conventional sliding throttle valve carburetor or in the sliding throttle valve carburetor of the present invention. When the throttle valve 3 is in a low opening state, a small flow rate A (L / H) fuel is required.
[0023]
According to the sliding throttle valve carburetor of the present invention, the negative pressure applied to the needle jet 11 can be reduced as compared with the negative pressure applied to the needle jet of the conventional sliding throttle valve carburetor as described above. Thus, the amount of fuel sucked into the intake passage 2 from the needle jet 11 as the main fuel control system M can be reduced corresponding to the decrease in the negative pressure.
In the low opening state of the sliding throttle valve 3, the necessary small flow rate A (L / H) is still necessary, and in order to obtain this small flow rate A (L / H), the low speed fuel control is performed. It is necessary to increase the amount of fuel supplied from the bypass hole 17 as the system S into the intake passage 2 in correspondence with the decrease in the fuel amount of the main fuel control system M.
The increase in the low speed fuel from the bypass hole 17 can be easily achieved by increasing the throttle diameter of the low speed fuel jet 15.
[0024]
According to the above, since the increased amount of low speed fuel is continuously supplied into the intake passage 2 from the low opening state of the sliding throttle valve 3 through the bypass hole 17, the engine is accelerated from the bypass hole 17 during the acceleration operation of the engine. The fuel can be easily sucked into the intake passage 2, thereby improving responsiveness and torque feeling during acceleration operation and further improving the linear characteristics of the engine.
[0025]
In addition, if the throttle diameter of the low-speed fuel jet 15 can be increased by the above, it is possible to improve the dustiness of the throttle diameter portion of the low-speed fuel jet 15, which is preferable from the viewpoint of quality maintenance.
Furthermore, the processing of the throttle diameter portion is facilitated, and the productivity of the low speed fuel jet 15 can be improved.
[0026]
In addition, according to the present control protrusion 20, a symmetrical shape is formed with respect to the longitudinal axis XX of the intake passage 2, and a pair of side surfaces 20B and 20C directed from the upstream top 20A to the downstream D are provided. This makes it possible to achieve uniform atomization of the fuel and improve the combustibility of the engine. That is, firstly, the fuel sucked into the intake passage 2 from the needle jet 11 collides with the upstream top portion 20A of the control projection 20 and then the longitudinal axis XX along the side surfaces 20B and 20C. This is because they are separated and diffused symmetrically.
This fuel flow is shown in FIG.
Second, it is controlled that the fuel sucked into the intake passage 2 from the needle jet 11 collides with the fuel sucked into the intake passage 2 directly from the bypass hole 17.
[0027]
Another embodiment of the control protrusion 20 is shown in FIGS.
FIG. 7 shows an example of a triangular pyramid shape,
FIG. 8 shows an example of a triangular prism shape,
FIG. 9 shows an example of a semi-cylindrical shape,
FIG. 10 shows an example of a cylindrical shape.
These shapes are appropriately selected by experiment.
[0028]
【The invention's effect】
As described above, according to the sliding throttle valve type vaporizer of the present invention,
At the bottom of the intake passage between the opening to the intake passage of the needle jet and the opening to the intake passage of the bypass hole,
Providing a control projection protruding into the intake passage;
The control protrusion,
A pair of side surface portions that are on the needle jet hole side, have a symmetrical shape with respect to the longitudinal axis from the upstream top located on the longitudinal axis of the intake passage, and go downstream
Since it is formed by a downstream side surface portion that is on the bypass hole side and that crosses the longitudinal axis of the intake passage and whose both ends are connected to a pair of side surface portions, The ratio of fuel supply from the low-speed fuel control system consisting of holes and pilot outlet holes can be increased, which improves responsiveness and torque feeling during engine acceleration, and lowers the sliding throttle valve The linear characteristics of the engine when it is released from the engine can be improved.
[0029]
Further, it is preferable that the throttle diameter of the low speed fuel jet can be increased from the viewpoint of improving the quality maintenance and productivity of the low speed fuel jet.
[0030]
In addition, the control projection has a symmetrical shape with respect to the longitudinal axis XX of the intake passage, and a pair of side portions from the upstream top to the downstream D are provided, so that uniform atomization of the fuel is achieved. This has been achieved and the flammability of the engine has been greatly improved.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a sliding throttle valve type vaporizer according to the present invention.
FIG. 2 is a cross-sectional view of only the vaporizer body taken along line QQ in FIG.
FIG. 3 is a perspective view of a control protrusion 20 used in FIG.
4 is a top plan view of FIG. 1. FIG.
FIG. 5 is a side view of FIG. 1;
FIG. 6 is a diagram showing the relationship between the negative pressure applied to the intake passage and the rate of change of the negative pressure applied to the needle jet in the sliding throttle valve carburetor according to the present invention.
FIG. 7 is a perspective view showing an embodiment in which the control protrusion has a triangular pyramid shape.
FIG. 8 is a perspective view showing an embodiment in which the control protrusion has a triangular prism shape.
FIG. 9 is a perspective view showing an embodiment in which the control protrusion is a semi-cylindrical shape.
FIG. 10 is a perspective view showing an embodiment in which the control protrusion is cylindrical.
FIG. 11 is a longitudinal sectional view showing a conventional sliding throttle valve type carburetor.
12 is a cross-sectional view of only the vaporizer body taken along the line PP in FIG. 11. FIG.
[Explanation of symbols]
2 Intake passage 2E Bottom portion of the intake passage between the opening of the needle jet to the intake passage and the opening of the bypass hole to the intake passage 3 Sliding throttle valve 20 Control projection 20A Upstream top portion 20B, 20C Side surface portion 20D Downstream Side XX Longitudinal axis 11 of intake passage 11 Needle jet 17 Bypass hole

Claims (5)

A carburetor body 1 in which the intake passage 2 is controlled to be opened and closed by a sliding throttle valve 3 disposed in a throttle valve guide cylinder 2B provided continuously to the intake passage 2;
A float chamber body 4 which cooperates with the carburetor body 1 to form a float chamber 5 which holds a constant fuel liquid level therein;
One end opens to the bottom of the intake passage 2 via the needle jet 11,
A main fuel control system M in which the other end opens into the float chamber 5 via the main fuel jet 12 and a jet needle integrally attached to the sliding throttle valve 3 is inserted into the needle jet;
Low-speed fuel control with one end opened to the bottom 2A of the intake passage 2 facing the engine-side bottom surface 3A of the sliding throttle valve 3 through the bypass hole 17 and the other end opened into the float chamber 5 through the low-speed fuel jet 15 With system S;
In the sliding throttle valve type carburetor with
In the bottom portion 2E of the intake passage 2 between the opening of the needle jet 11 to the intake passage 2 and the opening of the bypass hole 17 to the intake passage 2,
Providing a control projection 20 projecting into the intake passage 2;
The control protrusion 20 is
A pair on the needle jet hole 11 side that is symmetrical with respect to the longitudinal axis XX from the upstream apex 20A located on the longitudinal axis XX of the intake passage 2 and goes toward the downstream D Side portions 20B and 20C of
A slide which is on the bypass hole 17 side and which is formed by a downstream side surface portion 20D which crosses the longitudinal axis XX of the intake passage 2 and whose both ends are connected to the pair of side surface portions 20B and 20C. Dynamic throttle valve type vaporizer. The sliding throttle valve type carburetor according to claim 1, wherein the control protrusion has a triangular pyramid shape. The sliding throttle valve type carburetor according to claim 1, wherein the control protrusion has a triangular prism shape. The sliding throttle valve type carburetor according to claim 1, wherein the control protrusion has a semi-cylindrical shape. The sliding throttle valve type carburetor according to claim 1, wherein the control protrusion has a cylindrical shape.

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