JPS60249657A - Carburetor using two kinds of fuel - Google Patents

Abstract

PURPOSE:To certainly suspend the feed of sub-fuel on the high-output range side by cutting-off the communication between an intermediate passage to an inflow passage and an effluence passage formed in the intermediate part of a sub- fuel feeding passage when a throttle valve is positioned on the high-output range side where the opening degree exceeds a prescribed value. CONSTITUTION:A carburetor 10 is equipped wwith a main float chamber 11 for storing kerosene as main fuel and a sub-float chamber 12 for storing gasoline as sub-fuel, and further equipped with an intake passage 13 which is opened and closed by a throttle valve 15 and the feeding passages 27 and 31 for main fuel and sub-fuel. In the intermediate part of the sub-fuel feeding passage 31, are formed an intermediate passage 35 drilled nearly in the radial direction of a throttle valve shaft 14, an inflow passage 36 which communicates to the sub- float chamber 12 and communicates to the intermediate passage 35 when the throttle valve 15 has a prescribed opening degree or less on the perfect closed side, and an effluence passage 37 which communicates to the intake passage 13 and communicates to the intermediate passage 35 when the throttle valve 15 has a prescribed opening degree or less on the perfectly closed side.

Description

[Detailed Description of the Invention] [Technical Field] The present invention uses a low-volatility fuel such as kerosene (kerosene) as the main fuel, and uses a high-volatility fuel such as gasoline, which has better vaporization and ignitability, as an auxiliary fuel. The present invention relates to a carburetor that uses two types of fuel and is suitable for application to an engine that is switched to use as an engine.

In outboard motors and the like, engines that switch between using different fuels as described above are employed in consideration of fuel economy. In this case, in low output ranges such as during startup and warm-up, gasoline can be supplied from the idle port located on the intake downstream side of the throttle valve, the bypass port located on the intake upstream side of the throttle valve, etc. In the high output range, a main fuel such as kerosene that can be supplied from the bypass port, main nozzle, etc. is used.

However, in the above-mentioned carburetor, even in the high output range when the throttle valve is fully open, the intake negative pressure acts on the idle port, bypass port, etc., so auxiliary fuel is supplied into the intake passage, which is uneconomical. There is a problem.

In addition, in order to eliminate the problem described in item 1, there is a method in which as the throttle valve opens, the internal pressure of the sub-float chamber containing the sub-fuel is gradually reduced to negative pressure, thereby making it possible to prevent the sub-fuel from flowing out in the high output range. has also been proposed, but it causes the disadvantage that the oil level in the sub-float chamber rises, and it is also difficult to completely prevent the outflow of sub-fuel in a high output range.

[Object of the Invention] An object of the present invention is to reliably stop the supply of auxiliary fuel on the high output range side with a simple structure.

[Structure of the Invention] In order to achieve the above object, the present invention includes a main float chamber that accommodates the main fuel, a sub-float chamber that accommodates the sub-fuel,
An intake passage that is opened and closed by a throttle valve fixed to the throttle valve shaft, a main fuel supply passage that leads the main fuel in the main float chamber to the intake passage, and an auxiliary fuel supply passage that leads the auxiliary fuel in the auxiliary float chamber to the intake passage. In a carburetor using two types of fuel, the intermediate passage is formed approximately in the radial direction of the throttle valve shaft, and the intermediate passage is connected to the sub-float chamber, and the intermediate passage is connected to the sub-float chamber, and the intermediate passage is opened when the throttle valve is under a predetermined opening on the fully closed side. An inlet passage that is connected to the intake passage and that can communicate with the intermediate passage when the throttle valve is at a predetermined opening on the fully closed side or less is connected to an auxiliary fuel supply passage. It is formed in the middle part of.

[Detailed description of the invention] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a carburetor 10 according to an embodiment of the present invention, FIG. 2 is a view taken along the line II-II in FIG. 1, and FIG. 3 is a main part of FIG. 4 is a sectional view taken along line IV-IV in FIG. 3, and FIG.
It is a sectional view of the main part along the line v-■ in the figure.

The carburetor IO uses kerosene as the main fuel and gasoline as an auxiliary fuel. That is, as shown in FIG. 1, at the lower center of the carburetor 10,
A main float chamber 11 is provided which accommodates kerosene as the main fuel. Furthermore, a sub-float chamber 2 is provided at the lower part of one side of the carburetor 10 to accommodate gasoline as a sub-fuel.

In addition, an intake passage 13 is formed in the carburetor 10, and the intake passage 13 is opened and closed by a throttle valve 15 fixed to a throttle valve shaft 14. is formed.

Further, a drive lever 16 that is swing-operated is pivotally supported on the upper part of the carburetor 10 by a throttle operation mechanism (not shown), and an arm 17 is fixed to the drive lever 16. A bent link 19 is attached to the arm 17 via a connector 18.
One end is rotatably connected. Bent link 1
The other end of the bracket 9 is movably supported by a guide hole 21 formed in the bracket 20 via a sliding body 22 . The middle part of the bent link 19 is connected to the throttle valve shaft 14.
The throttle lever 23 is connected via a sliding body 25 to a long hole 24 of a throttle lever 23 fixed to the protruding end of the throttle lever 23 . That is, in the carburetor 10, the throttle lever 23 is swung by driving the drive lever 16 and the bent link 19 by operating a throttle operation mechanism (not shown), and the throttle valve 15 inside the intake passage 13 is rotated. The opening/closing operation is possible between the fully closed position and the fully open position.

The carburetor 10 also has a main jet 2 in a main float chamber 11.
6, and a main nozzle 27 facing this main jet 26. A tip opening of the main nozzle 27 is opened to a venturi portion of the intake passage 13. Further, one end of an air bleed passage 28 is communicated with the main nozzle 27, and the other end of the air bleed passage 28 is opened to the atmosphere via an air jet 29. That is, in the carburetor 10, the main nozzle 27 forms a main fuel supply path, and during normal operation when the first throttle valve 15 is opened to a predetermined opening degree or more, the main jet 26 causes a metered amount of kerosene to flow into the carburetor from the air bleed passage 28. The kerosene mixture can be mixed with air and sucked out from the main nozzle 27 into the venturi section of the intake passage 13.

The carburetor 10 also includes a slow jet 30 in the sub-float chamber 12 , the slow jet 30 communicates with a slow system passage 32 via a sub fuel supply pipe 31 , and the slow system passage 32 communicates with a slow system passage 32 via a bypass port 33 . Throttle valve 1
It opens in the wall surface of the intake passage 13 adjacent to the air intake passage 5 . Further, a slow air jet 34 connected to the atmosphere is connected to the middle portion of the slow jet 30. That is, the carburetor 1O forms an auxiliary fuel supply path by the auxiliary fuel supply pipe 31, the slow system passage 32, and the bypass port 33, and at low output when the throttle valve 15 is in a predetermined opening range in a fully closed example,
Gasoline metered by the slow system passageway 30 is mixed with air flowing in from the slow air jet 34, and the gasoline mixture can be sucked out from the bypass port 33 into the intake passageway 13.

Therefore, in the middle part of the auxiliary fuel supply pipe 31, there is a third
As shown in FIG. 5(A), an intermediate passage bored approximately in the radial direction of the throttle valve shaft 14 is connected to the sub-float chamber 12, and the throttle valve 15 is opened to a predetermined opening degree 01 on the fully closed side. An inflow passage 36 that can communicate with the intermediate passage 35 under the following conditions, and an intermediate passage 36 that is connected to the intake passage 13 and under a condition where the throttle valve 15 is at a predetermined opening degree of 01 or less on the fully closed side.
An outflow path 37 is formed which can be communicated with. The inflow passage 36 and the outflow passage 37 are formed approximately in the radial direction of an annular body 38 fixed around the protruding portion of the throttle valve shaft 14 in the main body 10A of the carburetor 10.
is bored in the protruding portion of the throttle valve shaft 14. Further, the annular body 38 is fixed to the main body 10A together with the lid portion 40 by a set screw 39. Further, an intermediate path 35 is provided in each of the throttle valve shaft 14 and the annular body 38.
, an O-ring 41., which can prevent gasoline from leaking, is provided on both sides of the portion where the inlet passage 36 and the outlet passage 37 are formed.
42 are arranged. In addition, 43 is the throttle valve shaft 1
This is a locking ring that is engaged with the outer circumferential portion of 4. Also,
Reference numerals 44 and 45 designate connection pipes fitted into the inflow passage 36 and the outflow passage 37, respectively.

In FIG. 1, 46 is an acceleration pump that operates in conjunction with the opening and closing operations of the throttle valve 15 to increase the amount of acceleration fuel, 47 is a piston, 48 is a piston rod, and 49 is a pushing body.

Next, the operation of the embodiment described above will be explained.

When the throttle valve 15 is located within a predetermined opening degree θl on the fully closed side, that is, at the time of startup, warm-up, etc., an intermediate passage 35 formed in the intermediate part of the auxiliary fuel supply pipe 31; The inlet passage 36 and the outlet passage 37 communicate with each other, allowing gasoline in the sub-float chamber 12 to be supplied to the intake passage 13 of the carburetor 10.

On the other hand, when the throttle valve 15 is located in the high output region side exceeding the predetermined opening degree 01 on the fully closed side, the intermediate passage 35 formed in the intermediate part of the auxiliary fuel supply pipe 31 and the inflow passage 3
6. Communication with the outflow path 37 is cut off, and the sub-float chamber 12
The supply of gasoline to the intake passage 13 completely stops,
Only kerosene in the main float chamber 11 can be supplied to the intake passage 13 of the carburetor 10.

Note that the operating range in which gasoline as the auxiliary fuel can be supplied, that is, the opening range of the throttle valve 15, can be expanded by increasing the hole diameters of the intermediate passage 35, the inflow passage 36, and the outflow passage 37. .

FIG. 5(B) shows that the middle path 3 is different from the example of FIG. 5(A).
This is an example in which the opening range of the throttle valve 15 that can supply gasoline as an auxiliary fuel is expanded to θ2 by increasing the diameter of the hole 5.

[Effects of the Invention] As described above, the present invention provides a main float chamber for accommodating main fuel, a auxiliary float chamber for accommodating auxiliary fuel, and an intake passage opened and closed by a throttle valve fixed to a throttle valve shaft. A dual fuel carburetor having a main fuel supply passage for guiding the main fuel in the main float chamber to the intake passage, and an auxiliary fuel supply passage for guiding the auxiliary fuel in the auxiliary float chamber to the intake passage. An intermediate passage bored approximately in the radial direction of the shaft, an inflow passage connected to the sub-float chamber and capable of communicating with the intermediate passage when the throttle valve is below a predetermined opening on the fully closed side, and an intake passage. At the same time, the throttle valve is below the specified opening on the fully closed side! ! ! - An outflow passage that can communicate with the intermediate passage at the bottom is formed in the intermediate part of the auxiliary fuel supply passage. Therefore, when the throttle valve is located at a predetermined opening on the fully closed side, the inflow passage and the outflow passage can communicate with the intermediate passage, and on the other hand, when the throttle valve is located on the high output range side exceeding the predetermined opening, By cutting off the communication between the inflow path and the outflow path and the intermediate path, it becomes possible to reliably stop the supply of auxiliary fuel on the high output region side with a simple structure.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a vaporizer according to an embodiment of the present invention;
Figure 2 is II~ of Figure 1! 3 is a cross-sectional view showing the main parts of FIG. 1, FIG. 4 is a view taken along line IV-IV in FIG. 3, and FIG. 5 (B) is a sectional view of the main part along the line V-V in Figure 3, and Figure 5 (A
) is a cross-sectional view showing a modification example. 10... Carburizer, 11... Main float chamber, 12...
- Sub-foot chamber, 13... Intake passage, 14... Throttle valve shaft, 15... Throttle valve, 27... Main nozzle, 31... Sub-fuel supply pipe, 32... Slow passage, 33... Bypass port, 35... Intermediate passage,
36...Inflow path, 37...Outflow path. Agent Patent Attorney Osamu Shiokawa

Claims (1)

[Claims] (1) A main float chamber that accommodates the main fuel, a sub-float chamber that accommodates the sub-fuel, an intake passage that is opened and closed by a throttle valve fixed to the throttle valve shaft, and an intake passage that carries the main fuel in the main float chamber. In a carburetor using dual fuel, which has a main fuel supply passage leading to the intake passage, and an auxiliary fuel supply passage leading the auxiliary fuel in the auxiliary float chamber to the intake passage, an intermediate fuel supply passage formed approximately in the radial direction of the throttle valve shaft is used. an inlet passage that is connected to the sub-float chamber and can communicate with the intermediate passage when the throttle valve is at a predetermined opening on the fully closed side or less; 1. A carburetor using two types of fuel, characterized in that an outflow passage that can communicate with the intermediate passage under conditions of less than 100 liters is formed in the intermediate part of the auxiliary fuel supply passage.