JPS6032366Y2 - vaporizer - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to the structure of an engine carburetor, and in particular to a structure for preventing the mixture from becoming over-enriched during high-load operation in a carburetor used in an automobile engine. Regarding.

[Conventional technology]

A conventional example of a carburetor for an automobile engine is shown in FIG.

A large venturi 2 and a small venturi 3 are formed in the intake passage 1 to increase the flow velocity of air taken into the intake passage 1.

This increase in air flow velocity causes the air pressure within the intake passage 1, particularly between the small venturi 3, to become negative, and fuel is sucked out from the main nozzle 4 provided in this negative pressure area to create an air-fuel mixture.

This fuel is supplied from the fuel tank into the float chamber 5 via a needle valve (not shown).

The float 5' opens and closes this needle valve (not shown) to keep the fuel oil level in the float chamber 5 constant.

The upper part of the float chamber 5 is communicated with the upstream side of the intake passage 1 through an inner vent 6, and the fuel oil level receives positive pressure due to the difference between the upstream pressure and the pressure at the negative pressure area where the main nozzle 4 is provided. .

As a result, fuel passes through the main jet 7, the main fuel passage 8, and is sucked out from the main nozzle 4 into the intake passage 1.

The amount of fuel sucked out is adjusted by adjusting the amount of air by the opening degree of the throttle valve 9.

Further, a power valve 10 is provided for increasing the amount of fuel sucked out when the accelerator pedal is depressed and the opening degree of the throttle valve 9 increases and the negative pressure downstream of the throttle valve 9 decreases.

This power valve 10 is normally closed by the negative pressure downstream of the throttle valve 9 being guided by the power negative pressure passage 11 and pulling up the power piston 12 .

When the negative pressure decreases, the power spring 13, which has been hit by the negative pressure, pushes down the power piston 12,
The power valve 10 is opened, fuel is supplied through the power jet 14, and the mixture becomes rich.

〔problem〕

In a carburetor with such a structure, the power valve 10
When the pump is operating and the amount of fuel sucked out is increased, engine vibration is added to the ripples in the fuel liquid level in the float chamber 5 due to the fuel being vigorously supplied to the float chamber 5 from a needle valve (not shown). The entire fuel in the float chamber 5 now contains many air bubbles, and the fuel whose specific gravity has decreased due to the formation of air bubbles is sucked into the intake passage 1 from the inner vent 6 in large quantities due to the negative pressure generated in the inner vent 6. The problem is that the air-fuel mixture that is discharged and supplied to the engine combustion chamber becomes too rich, and in some cases, the engine rotation stops.

[Purpose of invention]

The present invention was developed to eliminate the above-mentioned drawbacks of the conventional technology, and prevents the fuel bubbles in the upper part of the float chamber from being sucked out into the mixture passage through the inner vent when the power valve is operating. Therefore, it is an object of the present invention to provide a carburetor that does not cause problems such as engine rotation stoppage.

[Means to achieve the purpose]

The carburetor of this invention has a communication passage that communicates between the upper part of the float chamber and the power negative pressure passage, and when the power valve is operating, the communication passage is open, and when it is not operating, the communication passage is closed. It is something to do.

This opening and closing is performed by the power piston of the power valve.

As a result, when the power valve operates and fuel bubbles are easily sucked out from the inner venturi, the communication passage opens to scavenge the inside of the float chamber and collapse the fuel bubbles.

[Example of idea]

An embodiment of the present invention will be explained with reference to FIG.

Incidentally, the same parts as in FIG. 2 are given the same numbers and the explanation will be omitted.

A communication passage 20 is provided that communicates the upper part of the float chamber 5 with the power negative pressure passage 11 midway.

The opening 21 of this communication passage 20 is formed near the power piston 12.

Then, the power piston 1 is moved by the power spring 13.
2 is pushed down and the power valve 10 is supplying fuel, the opening 21 of the communication passage 20 is opened.

Conversely, when the power piston 12 is pulled up by the negative pressure guided by the power negative pressure passage 11 and the power valve 10 is not supplying fuel, the opening 21 of the communication passage 20 is closed.

In this embodiment, when the accelerator pedal is depressed under high load and the power valve 10 for enriching the air-fuel mixture is activated, the communication passage 20 is brought into communication with the power negative pressure passage 11 by the action of the power piston 12, so that the float Air bubbles generated in the chamber 5 are scavenged by the air flow flowing downstream of the throttle valve 9 in the intake passage 1 via the inner vent 6, the float chamber 5, the communication passage 20, and the power negative pressure passage 11, and the air bubbles are removed from the fuel. is crushed, so the intake passage 1 is removed from the inner vent 6.
is prevented from being discharged to the upstream side of the venturi.

In the normal operating state, the power piston 12 of the power valve 10 is pulled upward in the drawing against the power spring 13 by the intake negative pressure acting on the downstream side of the throttle valve 9 in the intake passage 1. Therefore, the communication path 20 is in a state of being closed by the power piston 12.

As a result, under normal operating conditions, the presence of the communication passage 20 does not affect the carburetor.

[Effect of idea]

According to the carburetor of the present invention, when the power valve, which tends to suck out fuel bubbles from the inner vent, the fuel bubbles generated in the float chamber are crushed by the scavenging air, and therefore, a large amount of fuel bubbles are sucked into the intake passage from the inner vent. This has the effect of preventing the problem of being ejected.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of a carburetor according to an embodiment of the present invention, and FIG. 2 is a sectional view showing the structure of a conventional vaporizer. 1...Intake passage, 2...Large venturi, 3...Small venturi, 4...
...Main nozzle, 5...Float chamber, 5'----
---Float, 6... Inner vent, 7...
...Main jet, 8...Main fuel communication, 9.
... Throttle valve, 10... Power valve, 11.
... Power negative pressure passage, 12 ... Power piston, 13 ... Power spring, 14 ...
...Power jet, 20...Communication path, 2
1...Opening.

Claims (1)

[Scope of utility model registration request] In the carburetor, the upstream side of the venturi in the intake passage and the upper part of the float chamber are communicated by an inner vent, and the power negative pressure passage for operating the power valve is opened downstream of the throttle valve in the intake passage. A carburetor characterized in that a communication passage is provided that communicates between an upper part and a power negative pressure passage, and a power piston of the power valve closes the communication passage when the power valve is not supplying fuel.