JP4051826B2 - Main air passage of multiple carburetor - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a carburetor that adjusts and controls the concentration and amount of an air-fuel mixture supplied to an engine, and more particularly, a multiple carburetor in which a plurality of carburetors are arranged, and directed to a main fuel system of each carburetor The main air passage for supplying air.
[0002]
[Prior art]
The main air passage of the conventional multiple vaporizer is shown in FIG.
Each vaporizer constituting the multiple vaporizer is configured as follows.
Reference numeral 1 denotes a carburetor main body, through which an intake passage 2 passes and is controlled to be opened and closed by a throttle valve (not shown). Reference numeral 3 denotes a floating chamber body disposed at a lower position of the vaporizer body 1. The floating body 4 is formed by the vaporizer body and the floating chamber body 3, and the floating chamber 4 includes a floating element 5 and the like. A constant fuel liquid level XX is formed by the liquid level control mechanism.
M is a main fuel system comprising a main fuel jet 6 and a main nozzle 7 having a bleed hole 7A. The fuel in the float chamber 4 is controlled by the main fuel jet 6 and passes through the main nozzle 7. Sucked into the venturi portion V provided in the intake passage 2.
A is a main air system for supplying air to the main fuel system M. The air controlled by the main air jet 9 into the well chamber W formed by surrounding the outer periphery of the main nozzle 7 from the main air passage 8. Is supplied.
That is, air in the atmospheric chamber 10 of the carburetor body 1 is controlled by the main air jet 9, and this air is supplied into the well chamber W through the main air passage 8, and then from the bleed hole 7 </ b> A to the main nozzle 7. Supplied in. In the main nozzle 7, the main fuel controlled by the main fuel jet 6 and the main air are mixed, and this air-fuel mixture is sucked into the venturi portion V from the tip of the main nozzle 7.
A plurality of the single vaporizers are arranged, and throttle valves (not shown) of the vaporizers are linked and connected to form a multiple vaporizer.
[0003]
[Problems to be solved by the invention]
According to the main air passage of such a conventional multi-stage carburetor, the degree of freedom of adjustment of the mixture concentration A / F is low, and it takes a long time to set the carburetor to adapt to the required mixture ratio of the engine. It was not preferable in improving the efficiency.
For example, as shown in FIG. 2, according to the one using the main air passage of the single vaporizer constituting the conventional multiple vaporizer described above, the intermediate opening operation 3500 rpm to the high opening operation 5500 rpm. In the meantime, the air-fuel mixture concentration A / F becomes approximately constant 13.
On the other hand, the air-fuel mixture concentration A / F characteristics required by the engine are those in which the lightness is required in the intermediate opening operation region and the darkness is required in the high opening operation region. In the conventional single vaporizer having the density A / F characteristic, the setting operation is difficult.
That is, if the mixture concentration A / F in the intermediate opening operation is set to the required thin, the mixture concentration A / F in the high opening operation becomes thin, while the mixture concentration A / F in the high opening operation is requested. If it is set to dark, the mixture concentration in the intermediate opening operation becomes dark.
Also, in a multi-cylinder engine using multiple carburetors, the combustion state may be slightly different for each cylinder. According to this, the required mixture ratio concentration characteristics for each carburetor connected to each cylinder are different. There is.
According to the above, it is necessary to change the air-fuel mixture concentration A / F for each vaporizer, which is also not preferable for improving the development efficiency.
[0004]
The main air passage of the multiple carburetor according to the present invention is made in view of the above-mentioned problems, and in particular, easily adjusts the air-fuel mixture concentration A / F characteristics during the period from the intermediate opening operation to the high opening operation. Further, it is possible to provide a multiple carburetor with excellent setting workability, which can easily change the air-fuel mixture concentration A / F for each carburetor, thereby improving the engine performance. The purpose is to improve development efficiency.
[0005]
[Means for achieving the object]
In order to achieve the above object, the multiple carburetor according to the present invention includes a carburetor main body through which an intake passage passes and the intake passage is controlled to be opened and closed by a throttle valve, and a venturi portion formed in the intake passage. A plurality of carburetors including a main nozzle having a bleed hole that is open to the main chamber and a main air passage that supplies main air to a well chamber that surrounds the outer periphery of the main nozzle. In an interlocked and connected multiple vaporizer, an air pipe made of a pipe material is connected to an end of each main air passage of each of the vaporizers, and the air pipes are opened to the atmosphere and the air of each of the vaporizers It is characterized by changing the length of the tube .
[00 06 ]
[Action]
According to the present invention, in each carburetor, the air flowing from the main air passage to the well chamber is influenced by the intake air pulsation in the air pipe, and the air-fuel mixture concentration A / F characteristic during the period from the intermediate opening operation to the high opening operation is obtained. At this time, by changing the length of the intake pipe in each carburetor, the mixture concentration A / F characteristic of each carburetor can be changed within a very small range.
[00 07 ]
【Example】
An embodiment of the main air passage of the multiple carburetor according to the present invention will be described below with reference to FIG.
In addition, about the same structure part as FIG. 3, description is abbreviate | omitted using the same code | symbol.
The following is provided in the single vaporizer which comprises a multiple vaporizer.
Reference numeral 20 denotes a main air passage having one end opened in the well chamber W and the other end opened through an air pipe 21 made of a pipe material on the atmospheric pressure side of the vaporizer body 1.
More specifically, the carburetor main body 1 has a first air passage 20A formed in the well chamber W from the side end 1A thereof and opened to the side end 1A. An air joint 20B is press-fitted into 20A, and an air pipe 21 made of a rubber pipe material is connected to the air joint 20B.
According to the above, the main air passage 20 is formed by the air pipe 21, the air joint 20 </ b> B, and the first air passage 20 </ b> A from upstream to downstream, and the air intake port 20 </ b> C of the main air passage 20 Open end.
A main air jet J1 that controls the amount of main air flowing through the main air passage 20 is disposed in the air joint 20B.
A plurality of vaporizers are arranged to form a multiple vaporizer. In this example, three vaporizers are arranged in the vertical direction.
[00 08 ]
Next, a test result of a single vaporizer in the multiple vaporizer according to the present invention is shown in FIG.
In FIG. 2, the vertical axis indicates the air-fuel ratio A / F, and the horizontal axis indicates the engine speed rpm.
The symbols in the figure are as follows.
A square indicates a conventional vaporizer shown in FIG.
The mark ● indicates the vaporizer of the present invention in which the length L of the air tube 21 is 10 mm.
The symbol (2) indicates the vaporizer of the present invention in which the length L of the air pipe 21 is 150 mm.
The symbol ▲ indicates the vaporizer of the present invention in which the length L of the air tube 21 is 280 mm.
A circle indicates a vaporizer of the present invention in which the length L of the air tube 21 is 430 mm.
From the above experimental results, the following will be clarified.
According to the conventional carburetor shown in FIG. 3 that does not include the air pipe 21, the air-fuel mixture concentration A / F shows a substantially constant 13 between the engine speed of 3500 rpm and 5500 rpm.
According to this, as described above, it is difficult to change the mixture concentration A / F during the intermediate opening operation and the mixture concentration A / F during the high opening operation.
In the case where the length L of the air pipe 21 is 10 mm, 150 mm, and 430 mm, the air-fuel mixture concentration A / F can be greatly increased particularly at 4000 rpm and 4500 rpm of the engine.
Further, the air pipe 21 has a length L of 280 mm, and the air-fuel mixture concentration A / F can be increased at 4000 rpm of the engine.
That is, according to the main air passage of the multiple carburetor of the present invention, the main air passage 20 is opened to the atmosphere through the air pipe 21 made of a pipe material, so that the specific rotational speed range higher than the intermediate opening operation of the engine. In this case, the air-fuel mixture concentration A / F can be increased, thereby improving the setting workability of the vaporizer and improving the development efficiency.
In addition, since the mixture concentration A / F characteristic of each carburetor can be changed by simply changing the length L of the air tube 21 of each carburetor, the optimum mixture required by the cylinder in a multi-cylinder engine can be changed. Concentrations can be supplied from each carburetor, thus greatly improving engine performance.
The above is caused by the fact that the pulsating pressure generated in the engine acts in each air pipe 21 via the intake passage 2 of each carburetor and affects each air flow passing through the main air jet J1. it is conceivable that.
[00 09 ]
The air passage 23 having the conventional main air jet 9 is branched from the first air passage 20A of each carburetor so that a part of the main air amount going into the well chamber W is borne by the main air jet 9. Also good.
[00 10 ]
【The invention's effect】
As described above, according to the main air passage of the multiple vaporizer according to the present invention, in the multiple vaporizer in which a plurality of single vaporizers are arranged and the throttle valves of the vaporizers are linked and connected. connect the air tube made of a pipe material at the end of each main air passage of the carburetor, since the respective air tube changing the length of each air tube with open to air, an intermediate opening degree operating range of the engine The air-fuel mixture concentration A / F can be increased in the above specific rotational speed range, the concentration characteristic can be easily adjusted, setting workability can be improved, and development efficiency can be improved.
Further, the mixture concentration of each carburetor can be easily changed, and the optimum mixture can be supplied to each cylinder constituting the multi-cylinder engine very easily.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of a main air passage of a multiple vaporizer according to the present invention.
FIG. 2 is a diagram showing the relationship between the mixture concentration A / F of the carburetor and the engine speed (Ne rpm).
FIG. 3 is a longitudinal sectional view showing a main air passage of a conventional multiple carburetor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Vaporizer body 7 Main nozzle W Well chamber 20 Main air passage 21 Air pipe

Claims (1)

A carburetor body, through which the intake passage penetrates and the intake passage is controlled to be opened and closed by a throttle valve, a main nozzle having a bleed hole opened in a venturi section formed in the intake passage, and an outer periphery of the main nozzle A plurality of carburetors each including a main air passage for supplying main air into the surrounding well chamber, wherein the throttle valves of the carburetors are linked and connected to each other. An air pipe made of a pipe material is connected to the end of the main air passage, the air pipes are opened to the atmosphere, and the length (L) of the air pipe of each vaporizer is changed. The main air passage of the carburetor.

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