JPH0240063A - Constant-vacuum type carburetor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a carburetor that controls the concentration and amount of air-fuel mixture supplied to an internal combustion engine. A negative pressure responsive valve is arranged in a continuous negative pressure responsive valve guide cylinder, and the area of a part of the venturi formed by the negative pressure responsive valve and the intake duct is variably controlled by the negative pressure generated in the intake tract. This relates to a vacuum vaporizer.

[Conventional technology]

Conventionally, the first part about commonly used constant vacuum type vaporizers.
This will be explained using figures. 3 is a carburetor main body with an intake passage 2 horizontally passing through the interior, and a throttle valve shaft guide hole 3 is bored in the intake passage 2 at a horizontal position perpendicular to the intake passage 2, and the throttle valve is located in the chain hole. A shaft 4 is rotatably supported, and a circular butterfly valve 5 is attached to the throttle valve shaft.

A float chamber 7 is formed by the lower recess of the carburetor main body l and the float chamber main body 6, and a float is arranged in this float chamber 7, and the cooperative action of this float, a valve seat, and a float valve (both not shown) As a result, a constant liquid level is formed within the float chamber 7.

On the other hand, a negative pressure responsive valve guide cylinder 8 that opens upward in a direction perpendicular to the intake pipe 2 is connected to the middle part of the intake passage 2. A negative pressure responsive valve 9 that moves is disposed, and the lower part of this negative pressure responsive valve 9 and the intake passage 2 form a venturi portion (2).

The negative pressure responsive valve 9 has a lower plate 10, a partition 11 made of a diaphragm, etc., and an upper plate 12 arranged in sequence in a small diameter portion provided at the upper part thereof, and by caulking the upper part, they are connected to the negative pressure responsive valve 9. It is formed integrally with the

The partition body 11 is arranged on the carburetor main body recess 13 on the outer periphery of the negative pressure responsive valve guide tube 8 of the carburetor main body 1, and its upper part is forced to
-14, and the partition body 11 and the cover 14
A pressure receiving chamber P is formed in the partition body 11 and the carburetor main body recess 1.
3, an atmospheric chamber A is formed.

In addition, 15 is a negative pressure introduction hole bored in the bottom of the negative pressure responsive valve 9 to communicate with the intake passage 2, and 16 is a negative pressure introduction hole that is contracted into the pressure receiving chamber P, with one end connected to the cover 14 and the other end. A negative pressure responsive valve spring 17 is engaged with the negative pressure responsive valve 9, and 17 is a jet needle that is engaged with the negative pressure responsive valve 9. It is inserted into the 21 dol jets 18 that are connected below a constant liquid level.

Conventionally, negative pressure responsive valves integrally molded from a synthetic resin material such as polyamide resin are often used. This is because the synthetic resin material is lightweight, has excellent corrosion resistance, and is formed by molding so no processing is required.
This is to take advantage of the advantages of negative pressure responsive valves made of metal materials such as

[Problem to be solved by the invention]

However, while the negative pressure responsive valve 9 made of synthetic resin material has the above-mentioned excellent performance 9 functions, it has a lower thermal conductivity than negative pressure responsive valves made of metal materials such as zinc and aluminum. Therefore, there are the following problems.

By the way, the thermal conductivity of aluminum is 2.3 ca/see/crn'/0C/cm, and the thermal conductivity of polyamide resin is 0.4 can/sec/crn'/'O/Cm
It is.

In other words, when starting the engine in a state where the engine ambient temperature is relatively low, as the engine continues to warm up,
The temperature of the carburetor body 1 is increased by receiving heat conduction from the engine, but as described above, since the thermal conductivity of the synthetic resin material is low, the negative pressure responsive valve guide tube 8 of the carburetor body 1 The temperature of the negative pressure responsive valve 9 that slides through the valve 9 increases very slowly, so it cannot be expected that the temperature of the negative pressure responsive valve 9 will increase.

On the other hand, as the engine operates, the fuel in the float chamber 7 is sucked out into the intake passage 2 via the dollar jet 18, and this fuel is formed by the side wall of the intake passage 2 and the bottom of the negative pressure responsive valve 9. It is ejected in the form of mist into the venturi part V. Here, as mentioned above, since the negative pressure responsive valve 9 is in a low temperature state with a weak rise in temperature, the mist fuel sprayed into the venturi part V tends to adhere to the surface of the negative pressure responsive valve 9. It inhibits the improvement of fuel vaporization.

[Means to solve problems]

The constant vacuum type vaporizer according to the present invention was created in view of the above-mentioned problems, and has one function of the excellent performance of synthetic resin materials, and is a constant vacuum type vaporizer with excellent fuel atomization characteristics. In order to achieve the above object, a negative pressure responsive valve is formed of a synthetic resin material containing a conductive material, and an electric current is passed through the negative pressure responsive valve.

[Effect]

By directly passing a current through a synthetic resin material containing a conductive material, the negative pressure responsive valve itself generates heat, increasing the temperature of the negative pressure responsive valve. It is possible to maintain the engine temperature at a constant temperature or higher regardless of a decrease in engine ambient temperature or a decrease in temperature due to latent heat of vaporization.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. Incidentally, those having the same structure as the conventional one will be designated by the same reference numerals and the explanation will be omitted. Reference numeral 20 denotes a negative pressure responsive valve that performs the same function as the negative pressure responsive valve in a conventional constant vacuum type vaporizer. It is made of a composite resin material containing powder or fiber of a conductive material such as carbon.

A current is passed through this negative pressure responsive valve 20, and a specific example will be described below.

Reference numeral 2I denotes a cover made of a non-conductive material, and a first annular member 22 made of a conductive material such as copper is disposed approximately in the center of the cover. A second annular member 23 made of a conductive material and electrically isolated from the first annular member 22 is arranged. Reference numeral 24 denotes a negative pressure responsive valve spring that biases the negative pressure responsive valve 20 in the closing direction, and its lower end contacts the bottom 2OA of the negative pressure responsive valve 20.
The upper end thereof is brought into contact with the first annular member 22 .

Further, 25 is between the upper part of the negative pressure responsive valve 20 and the second annular member 23 such that its lower end is in contact with the upper part 20B of the negative pressure responsive valve 20, and its upper end is in contact with the second annular member 23. The negative pressure responsive valve spring 24 and the second spring 25, which are the compressed second springs, are both made of a conductive material.

The terminal 22A of the first annular member 22 and the terminal 23A of the second annular member 23 are connected by an electric circuit 27,
A power source 28 and an open/close switch 29 for controlling opening/closing of the electric circuit are arranged in series in this electric circuit 27 . facing 1
During operation when the engine ambient temperature is relatively low, the driver closes the on/off switch 28.

Then, the power supply 28, the first annular member 22, the negative pressure responsive valve spring, the negative pressure responsive valve 20, the second spring 25, the second annular member 23, and the on/off switch 28 form a closed circuit, and the negative pressure responsive valve 20 A current flows through.

According to this, the negative pressure responsive valve 20 as a whole generates heat by itself due to the conductive material contained in the synthetic resin forming the negative pressure responsive valve 20, thereby raising the temperature of the negative pressure responsive valve 20.

Therefore, even if the fuel in the mixture jetted into the venturi part V of the intake passage 2 through the needle jet 18 collides with the negative pressure responsive valve 20, the temperature of the negative pressure responsive valve 20 itself increases. Therefore, the fuel does not condense, and a mixture with excellent atomization properties can be supplied to the engine.

Note that the temperature rise of the negative pressure responsive valve 20 with respect to the current applied to the negative pressure responsive valve 20 is determined by the content ratio of the conductive material contained in the synthetic resin material as the base material, or by appropriately selecting the type of conductive material. Also, examples of the conductive material include iron.

There are copper, chromium, carbon, tungsten, nickel chromium, molybdenum, etc., and examples of synthetic resin materials as base materials include polyacetal, polyolefin, polystyrene, and polycarbonate.

There are polyamides, etc., and the material must be selected appropriately depending on the purpose.

Furthermore, if the open/close switch 17 is replaced with a manual switch and is replaced with a heat-sensing switch that closes only when the engine ambient temperature is below a certain temperature, the negative pressure responsive valve 20 can be automatically warmed to a certain temperature when the engine ambient temperature is low. It is something.

Furthermore, the method for passing current through the negative pressure responsive valve 20 is not limited to the negative pressure responsive valve spring 24 and the second spring 25 of the embodiment described above, and any method may be used as long as it achieves the above objective. .

〔Effect of the invention〕

As described above, the constant vacuum type vaporizer according to the present invention provides the following effects.

■It has the advantages of negative pressure responsive valves using synthetic resin materials, such as light weight and good corrosion resistance, but also allows the negative pressure responsive valve itself to generate heat to prevent the temperature of the negative pressure responsive valve from dropping. Therefore, the fuel flowing in the intake tract collides with the negative pressure responsive valve whose temperature has increased, especially when the negative pressure responsive valve is opened at a low opening.
The Venturi part has a small area, and the fuel atomization performance can be greatly improved even in a state where the engine atmosphere temperature is low.

■If the open/close switch placed in the electrical circuit of the negative pressure responsive valve is a heat sensitive switch, the negative pressure responsive valve will be automatically energized when the temperature of the intake air drawn into the intake tract is below a certain temperature. Since the pressure-responsive valve could be heated, no skill was required at all.

■Since the negative pressure responsive valve itself generates heat, it is possible to suppress the temperature drop throughout the negative pressure responsive valve, so when the engine is running, fuel adheres to the outer periphery of the negative pressure responsive valve due to blowback from the engine. Even if fuel were to be used, there was little chance of it adhering to the outer periphery, and fuel could be supplied to the engine continuously and uniformly.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a conventional constant vacuum type vaporizer, and FIG. 2 is a longitudinal sectional view showing an embodiment of the constant vacuum type vaporizer according to the present invention. 1. Carburetor main body 2. Intake path V. Venturi part 20. Negative pressure responsive valve 21. Cover 22. First annular member 23. , Second annular member 24, Negative pressure responsive valve spring 25, Second spring 28, Power supply 29, Open/close switch

Claims (5)

[Claims] (1) A negative pressure responsive valve is arranged in a negative pressure responsive valve guide cylinder connected to an intake path that penetrates the carburetor body, and a compartment body placed above the negative pressure responsive valve and a cover covering the compartment body are arranged. In a constant vacuum type vaporizer in which a pressure receiving chamber is formed in between, and an atmospheric chamber is formed in a concave portion of the vaporizer body on the outer periphery of the partition and the negative pressure responsive valve guide tube, the negative pressure responsive valve is made to contain a conductive material. A constant vacuum vaporizer made of synthetic resin material. (2) A negative pressure responsive valve is arranged in a negative pressure responsive valve guide cylinder connected to an intake path that penetrates the carburetor body, and a partition body placed above the negative pressure responsive valve and a cover covering the partition body are arranged. In a constant vacuum type vaporizer in which a pressure receiving chamber is formed in between, and an atmospheric chamber is formed in a concave portion of the vaporizer main body on the outer periphery of the dividing body and the negative pressure responsive valve guide cylinder, the negative pressure responsive valve is made to contain a conductive material. A constant vacuum type vaporizer made of a synthetic resin material and in which a current is passed through the negative pressure responsive valve. (3) A negative pressure responsive valve is arranged in a negative pressure responsive valve guide cylinder connected to an intake path that penetrates the carburetor body, and a partition body placed above the negative pressure responsive valve and a cover covering the partition body are arranged. In a constant vacuum type vaporizer in which a pressure receiving chamber is formed in between, and an atmospheric chamber is formed in a concave portion of the vaporizer body on the outer periphery of the partition and the negative pressure responsive valve guide tube, the negative pressure responsive valve is made to contain a conductive material. A constant vacuum type vaporizer made of a synthetic resin material and having an on/off switch for controlling the opening/closing of the current flowing to the sliding throttle valve in an electric circuit that causes current to flow through the negative pressure responsive valve. (4) The constant vacuum type vaporizer according to claim 3, wherein the opening/closing switch is a manual changeover switch. (5) The constant vacuum type vaporizer according to claim 3, wherein the opening/closing switch is a heat-sensitive switch that automatically closes the electric circuit only when the temperature is below a certain temperature.