JPH0727396Y2 - Vaporizer with starter - Google Patents

Description

[Detailed description of the device]

[0001]

The present invention relates to a mixed for starting to the engine
The present invention relates to the structure of a carburetor with a starter equipped with a starter for supplying aiki .

[0002]

2. Description of the Related Art A carburetor is connected in the middle of an intake passage of an engine so that fuel sent from a fuel tank or the like is temporarily held in a fuel chamber (usually a float chamber) and the flow velocity of the intake passage (engine speed) According to the above, the fuel in the fuel chamber is jetted into the intake passage through the main nozzle or the like to prepare the air-fuel mixture.

Further, the vaporizer is generally provided with a main system for preparing the air-fuel mixture in the medium to high speed range and a slow system for preparing the air-fuel mixture at idling and low speed. Further, in the carburetor, in addition to the main system and the slow system, a starter independent of these is provided, and this starter is operated at the time of engine start to activate a desired concentration (for example, air-fuel ratio
It is carried out to improve the startability by supplying an air-fuel mixture having / F of 9 to 12).

[0004]

However, in the conventional vaporizer with a starter of this kind, since the air-fuel ratio is uniquely set, the startability at room temperature (for example, 10 to 20 ° C.) is improved. If an excellent air-fuel ratio (for example, A / F = 9 to 12) is set, the startability may decrease at extremely low temperatures (for example, -20 ° C) because the air-fuel ratio is too thin. There was a case that fuel fogging occurred at room temperature. Therefore, the engine temperature of the cylinder head, etc.
Install a temperature sensor at a position where the required air-fuel ratio level can be detected.
Using the mechanical displacement or electrical output signal of the temperature sensing element
The air-fuel ratio and amount according to the starting temperature.
A starter that supplies a mixture has been proposed. This
References disclosing such a starter include, for example, JP-A-55.
-54651 is available. However , such engine temperature
The method of preparing the starting mixture by directly detecting the
Requires a heating element or drive circuit, which complicates the configuration.
Becomes uneconomical in terms of space and cost.
U

The present invention has been made in view of the above prior art, and an object of the present invention is to provide a complicated device such as a temperature detecting means.
With a simple and compact structure that does not require a structure, the star
Automatically adjusts the air-fuel ratio of the engine to an appropriate value corresponding to the engine temperature.
Can be adjusted to either low temperature or room temperature.
It will be possible to easily start the engine even if
In addition, the air flow resistance is small when the valve opening is small.
Can promote the atomization of fuel at low load,
It is an object of the present invention to provide a vaporizer with a starter that can further improve the mobility .

[0006]

The present invention relates to a carburetor equipped with a starter that mixes fuel measured by a starter valve with air to form a mixture and introduces the mixture into an intake passage from an air cleaner. an air passage for air intake of the starter system leading to the starter valve is provided integrally with the intake passage and substantially parallel to the carburetor body, into the air passage, the
From the upper rotation fulcrum of the air passage, cross the air passage and
It is formed by a leaf spring that extends in the opposite direction.When the intake negative pressure is weak, the opening of the air passage is reduced, and as the intake negative pressure becomes stronger, the opening of the air passage becomes larger. The object described above is achieved by providing a valve formed of a leaf spring that elastically displaces dynamically.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. FIG. 3 shows a vertical cross section of the carburetor with a starter according to one embodiment at a small opening, and FIG. 4 shows a cross section taken along line 4-4 in FIG. In FIG. 3, an intake passage 2 for introducing intake air in the direction of the arrow is formed in the carburetor main body 1, an air cleaner (not shown) is connected to the upstream side (the right side in FIG. 3), and the downstream side is the engine. It is connected to the intake hole of.

3 and 4, a vertical cylinder portion 3 is formed in the carburetor body 1, and a piston valve 4 that moves (moves up and down) across the intake passage 2 is inserted into the cylinder portion 3. Has been done. This piston valve 4 is controlled at its upper and lower positions, that is, the opening degree (venturi opening degree) of the intake passage 2 by a throttle wire 6 which is provided through a cap 5 fixed to the upper end of the cylinder portion 3 to prevent the air-fuel mixture from flowing into the engine. Controlled. Reference numeral 7 indicates a return spring of the piston valve 4.

A float chamber (fuel chamber) 9 is formed below the carburetor body 1 by mounting a bowl 8. The fuel level W in the float chamber 9 is automatically controlled to a predetermined height by opening and closing the fuel supply port 12 with a needle valve 11 that moves up and down together with the float 10. Between the fuel in the float chamber 9 and the venturi portion of the intake passage 2,
A main fuel system (main system) including a main jet 13 and a needle jet 14, and a low-speed fuel system (slow system) including a slow jet 15 and a slow air jet 16
And are provided. The atomized fuel is mainly discharged from the low-speed fuel system to the venturi in the low-speed operation region (for example, the opening degree is about 1/4 or less), and the atomized fuel is mainly discharged from the main fuel system in the higher opening degree (load operation). It is discharged to the Venturi.

A jet needle 17 connected to the piston valve 4 is inserted into the needle jet 14, and the amount of fuel discharged from the main fuel system is determined by the number of the main jet 13 and the insertion depth (up and down) of the jet needle 17. Position). A cutaway 18 for adjusting the air flow rate at low speed is formed on the upstream side (right side in FIG. 3 ) of the lower end surface of the piston valve 4.

In addition to the main fuel system and the low speed fuel system described above,
A starter system 20 is provided for preparing the air-fuel mixture at startup. 1 shows a longitudinal cross section of the starter 20 taken along line 1-1 in FIG. 4, and FIG. 2 shows a cross section taken along line 2-2 in FIG. 1 and 2, the vaporizer main body 1
A sliding starter valve 22 operated by a starter cable 21 is provided inside the starter valve 22.
The air passage 23, the fuel passage 24, and the mixture passage 2
The opening and closing of 5 is controlled. The air passage 23 is open to the air cleaner, and the fuel passage 2
4 communicates with the fuel in the float chamber 9 via a starter jet 26, and the mixture passage 25 opens into the intake passage 2.

The starter valve 22 is urged downward by a return spring 27, and the starter cable 2
When 1 is not operated, the starter valve 22 is at the lower limit position, the air passage 23 and the air-fuel mixture passage 25 are shut off, and the starter 20 is deactivated. In addition, the starter valve 22 is provided with a starter jet needle 28 for measuring the amount of fuel injection by controlling the amount of insertion in the fuel passage 24.

When the starter system is operated at the time of starting the engine, the starter valve 21 is moved upward by the starter cable 21 in FIGS. 1 and 2, and the air passage 23 and the air-fuel mixture passage 25 are communicated with each other as shown in the drawing. The opening degree of the fuel passage 24 is adjusted by the jet needle 28. When the engine is rotated in this state, air and fuel are sucked by the action of the intake negative pressure, and the air-fuel mixture is sucked into the engine through the air-fuel mixture passage 25.

In the air passage 23, however, an air amount adjusting means 30 that automatically opens and closes in response to negative intake pressure.
Is provided. The air amount adjusting means 30 reduces the opening area of the air passage 23 to reduce the intake air amount when the intake negative pressure is weak, and increases the opening area of the air passage 23 as the intake negative pressure increases to increase the intake air amount. It operates in response to the intake negative pressure so as to increase. In the embodiment shown in FIG. 1, the air amount adjusting means 30 is composed of a valve composed of a leaf spring 31 that is elastically displaced so as to change the opening area of the air passage 23 according to the intake negative pressure.
That is, the valve including the leaf spring 31 is in a position where the opening degree of the passage is reduced when the intake negative pressure introduced into the air passage 23 is small, and the intake negative pressure introduced into the air passage 23 increases as the intake negative pressure increases. It is attached so as to be elastically displaced in the direction of increasing the passage opening degree in response to the intake negative pressure. Further, the valve 31 composed of this leaf spring is shown in FIG.
As shown in FIG.
Made of leaf springs that extend downwards across the air passages
It

By the way, in the starter system 20 of this type, the air-fuel ratio A / F at room temperature (for example, around 10 ° C.).
Does not need to be so thick, for example, A / F = 9-12
However, it is required to set a low temperature (eg
At around −20 ° C.), it is necessary to make the air-fuel ratio A / F high in order to ensure the ease of starting. For example, A / F = 4 to
Setting to 7 is required. Further, when the engine is started, the rotational load such as oil (lubricating oil) viscosity is relatively small at room temperature, so that the engine speed at the time of starting is relatively high (for example, about 500 rpm), and thus the intake negative pressure is reduced. Relatively strong (eg 150 mmHg
It will be about).

On the other hand, at extremely low temperatures, the rotational load such as oil viscosity is large and the engine speed at start is low (for example,
Therefore, the intake negative pressure becomes weak (for example, about 100 mmHg). The present invention was completed in consideration of such a correlation between the engine temperature and the intake negative pressure, and by operating the valve (leaf spring) 31 of the air passage 23 by the intake negative pressure, As a result, the present invention provides a vaporizer with a starter capable of supplying a relatively thin starting mixture at normal temperature and supplying a relatively rich starting mixture at low temperature.

That is, according to the starter 20 described above, at normal temperature where the rotation resistance is small, the opening degree of the leaf spring 31 becomes large and a relatively large amount of air is supplied due to the strong intake negative pressure due to the high rotation speed. This allows the engine to be started with a relatively thin (not too rich) mixture. On the other hand, when the rotation resistance is large and the temperature is low, the opening degree of the leaf spring 31 becomes small due to the weak intake negative pressure due to the low rotation speed, and the engine can be started with a rich air-fuel mixture by reducing the supply air amount. Thus, there is no need for setting at extremely low temperatures , and the engine temperature etc.
Since the medium is not used as a medium, temperature detection means and drive means are complicated.
And requires extensive mechanical or electrical means.
First, inside the air passage 23 formed integrally with the carburetor main body 1.
Since the leaf spring 31 is provided, it can be applied to existing vaporizers as well.
Very easy and compact form that can be easily applied
The starter can be used at extremely low temperatures and at room temperature.
-20 air-fuel ratio and air-fuel ratio suitable for engine starting
A carburetor with a starter was obtained , which could be automatically adjusted to the values and could easily start the engine. FIG. 5 is a graph exemplifying the setting characteristic of the air amount control valve including the leaf spring 31 in FIG. 1, in which the horizontal axis represents the intake negative pressure,
The vertical axis represents the air-fuel ratio A / F.

According to the embodiment described above, the air-fuel ratio of the starter 20 can be automatically adjusted by using the intake negative pressure based on the engine speed, which varies depending on the temperature, as the medium, without using the temperature as the medium. With a simple and compact structure that does not require a complicated mechanism such as temperature detection means, the air-fuel ratio of the starter system can be automatically adjusted to an appropriate value corresponding to the engine temperature, and it can be used at both normal temperature and extremely low temperature. A carburetor with a starter was obtained that could easily start the engine. Furthermore, the valve 31 is
From the upper rotation fulcrum of the passage 23, cross the air passage
The valve opening is small because it is formed by a leaf spring that extends in the direction
The air flow resistance at the time of opening is reduced to reduce the fuel
Atomization can be promoted and startability is further improved.
be able to. In addition, in the illustrated embodiment, the case where the present invention is applied to the piston type carburetor has been described.
Regardless of the type of vaporizer such as a CV vaporizer, any vaporizer with a starter can be widely applied to these vaporizers.

[0019]

As is apparent from the above description, according to the present invention, the starter for mixing the fuel measured by the starter valve with the air to form the air-fuel mixture and introducing the air-fuel mixture into the intake passage is provided. In the carburetor, an air passage for intake of a starter system from an air cleaner to a starter valve is integrally provided in the carburetor main body substantially in parallel with the intake passage, and the upper passage of the air passage is rotated in the air passage. fulcrum
Formed from a leaf spring extending downwardly across the air passage from the
When the intake negative pressure is weak, the opening of the air passage is decreased, and the opening of the air passage is increased as the intake negative pressure is increased. The leaf spring is automatically elastically displaced in response to the intake negative pressure. since the configuration in which the valve comprising a temperature detection
Simple and compact without requiring complicated mechanism such as output means
The air-fuel ratio of the starter corresponds to the engine temperature with a simple configuration
Can be automatically adjusted to the proper value
And easily start the engine at any temperature
It is also possible to open the valve in the air passage
Downward across the air passage from the upper pivot of the air passage
Since it is formed by a leaf spring that extends in the vertical direction, the valve opening is small
Atomization of fuel at low load by reducing air flow resistance during operation
Can be promoted and startability can be further improved.
A vaporizer with a starter capable of performing is provided.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the structure of a main part of a carburetor with a starter according to an embodiment of the present invention, taken along line 1-1 in FIG.

2 is a cross-sectional view taken along the line 2-2 in FIG.

FIG. 3 is a vertical cross-sectional view of a central portion of a carburetor with a starter according to an embodiment of the present invention.

4 is a cross-sectional view taken along the line 4-4 in FIG.

5 is a graph illustrating an air supply amount setting characteristic with respect to the intake negative pressure of the leaf spring in FIG.

[Explanation of symbols]

 1 Vaporizer Main Body 2 Intake Passage 4 Piston Valve 9 Float Chamber 13 Main Jet 15 Slow Jet 17 Jet Needle 20 Starter 21 Starter Cable 22 Starter Valve 23 Air Passage 24 Fuel Passage 25 Mixture Passage 26 Starter Jet 28 Starter Jet Needle 30 Air Volume Adjusting means 31 Leaf spring (valve)

Claims (1)

[Scope of utility model registration request] 1. A carburetor equipped with a starter for mixing a fuel measured by a starter valve into air to form an air-fuel mixture, and introducing the air-fuel mixture into an intake passage, a starter system from an air cleaner to a starter valve. An air passage for intake of air is provided integrally with the carburetor main body substantially parallel to the intake passage, and the upper side of the air passage is rotated in the air passage.
With a leaf spring extending downward from the fulcrum across the air passage
A plate that is formed and reduces the opening of the air passage when the intake negative pressure is weak, and automatically elastically displaces in response to the intake negative pressure in a direction in which the opening of the air passage increases as the intake negative pressure increases. A vaporizer with a starter, which is provided with a valve made of a spring.