JPS598663B2 - Vaporizer air vent switching device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION 5. The present invention relates to a carburetor used in an internal combustion engine for an automobile, and more particularly to a switching device for an air vent provided in the carburetor.

The air vent of the carburetor consists of an inner vent that communicates from the float chamber of the carburetor to the air passage of the carburetor, and an outer vent that communicates with the outside of the carburetor.

Air vent switching is accomplished by electrically or mechanically actuated valves.

In an automobile internal combustion engine, when the outside air, the engine, or the inside of the engine room becomes high temperature, the carburetor installed nearby also becomes high temperature, and the amount of evaporation of fuel 15 in the float chamber increases.

Particularly during no-load operation, light-load operation, and when the engine is stopped, the amount of fuel evaporated increases undesirably.

That is, because this evaporated gas is sucked into the engine from the inner vent, and because the pressure in the float chamber is high, a large amount of fuel is temporarily jetted from each fuel injection port into the intake pipe, so the concentration of the air-fuel mixture decreases. This causes so-called percolation phenomena such as excessively large engine speeds, idle link failures, engine stalls, or restart failures.

It is therefore an object of the present invention to provide an improved carburetor air vent switching device that does not cause the percolation 25 phenomenon.

According to the present invention, an inner vent that communicates the air passage of the carburetor with the upper part of the float chamber, an outer vent 30 that communicates the upper part of the float chamber with the outside of the carburetor, and a switch that communicates the upper part of the float with the inner vent or the outer vent. A vaporizer air vent switching device is provided 35 comprising a valve and a controller connected to the switching valve for controlling the switching valve in response to a condition that causes a percolation phenomenon.

The air vent switching device for a carburetor according to the present invention includes a control device that controls the switching valve that switches between the inner vent and the outer vent in response to conditions that cause a percolation phenomenon.
When the engine becomes hot and the temperature of the carburetor increases due to light load operation or engine stop, the control device
The switching valve is driven to close the inner vent side passage and establish an outer vent state to reliably prevent the occurrence of percolation.

According to the first embodiment of the present invention, the control device includes a series circuit of a solenoid valve, a key switch, and a battery.

When the key switch is off, the solenoid valve opens and drives the switching valve to close the inner vent and establish the outer vent condition.

According to a second embodiment of the invention, the control device comprises a series circuit of a solenoid valve, a thermoswitch, and a battery.

When the temperature of the thermoswitch is high, it turns off and the solenoid valve opens, driving the switching valve to close the inner vent and establish the outer vent state.

According to a third embodiment of the invention, the control device comprises a thermobulp.

When the temperature of the thermovalve becomes high, the switching valve is activated to close the inner vent and establish the outer vent state.

According to the present invention, the control device includes a one-way ventilation type check valve communicating with the switching valve.

When the negative pressure of the negative pressure source becomes lower than that of the check valve, the check valve disconnects the negative pressure pipe and maintains the negative pressure to ensure closure of the outer vent side passage.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic sectional view showing an embodiment of an air vent switching device for a carburetor according to the present invention.

When the air that has passed through the air passage 12 of the carburetor 10 passes through the venturi 14, its speed increases and the pressure decreases, so the fuel in the float chamber 18 is sucked out from the nozzle 16, atomized and vaporized, and mixed with air. It becomes a mixed gas.

This mixed gas is controlled by a slot valve 20 that is linked to an accelerator pedal, and is supplied to a cylinder (not shown) through an intake pipe 22.

The air passage 12 communicates with the upper part of the float chamber 18 by an inner vent 24.

When the pressure inside the carburetor falls below the pressure inside the float chamber, the inner vent 24 keeps both pressures equal and prevents an increase in fuel consumption.

As shown in the figure, when the key switch 26 is off, the current flowing from the vanteri 2B to the solenoid valve 30 is cut off, the port of the solenoid valve 30 remains open, and the atmosphere flows through the air passage 1.
2 to the atmosphere port 13 and the atmosphere passage 32 to the electromagnetic box 30.
The switching valve, that is, the negative pressure responsive switching valve actuating device 34 is input from the port of the switching valve 34' to the inner vent to close the passage on the inner vent side.

In this way, when the outer vent state is established, the funnel chamber 18 communicates with the outside of the carburetor 10 through the outer vent 36, so there is no rise in pressure in the float chamber due to evaporated gas in the float chamber 18, and the evaporated gas does not reach the inner vent 24 or the engine. percolation is prevented because it is not inhaled.

By providing a canister 38 after the outer vent 36, it is also possible to prevent evaporated gas from being released into the atmosphere.

Now, when the key switch 26 is turned on and the engine is put into operation, current flows through the electromagnetic cell 30 and the port of the electromagnetic cell 30 is closed, and the negative pressure in the intake pipe 22 is transferred from the take-out port 40 to the check valve 42 to the negative pressure pipe. 44 and acts on the negative pressure responsive switching valve operating device 34 to push the valve of the switching valve 34' toward the outer vent 36, thereby closing the outer vent side passage.

As a result, the float chamber 18 communicates with the air passage 12 through the inner vent 24 and enters a normal operating state.

The check valve 42 is of a one-way ventilation type, and even if the negative pressure in the intake pipe 22 decreases during high-load operation, the check valve 42
4 and the extraction port 40 and vent switching valve 3
To prevent 4' from closing the inner vent side passage,
It operates to maintain the negative pressure in the negative pressure pipe 44 and the negative pressure responsive switching valve actuating device 34.

FIG. 2 is a schematic sectional view showing another embodiment of the air vent switching device for a carburetor according to the present invention.

Parts corresponding to the apparatus of FIG. 1 are designated with the same reference numerals.

In this embodiment, a thermoswitch 46 is provided in the engine cooling water 45, and its contacts are connected in series to a circuit consisting of a battery 28, a key switch 26, and a solenoid valve 30.

This thermoswitch 46 is of a type that is turned on when the humidity is low and turned off when the temperature is high.

Now, the key switch 26 was turned on and the engine was running, but when the temperature of the engine cooling water 45 becomes high, and therefore the temperature of the carburetor 10 becomes high and percolation is likely to occur, the thermo switch 46 is turned off. No, since the port of the solenoid valve 30 is opened, the switching valve 34
' closes the inner vent side passage to form an outer vent state and prevent the percolation phenomenon.

When the temperature of the engine cooling water 45 becomes low, the thermoswitch 46 is turned on and closes the solenoid valve 30, so that the switching valve 34' closes the outer vent side passage and realizes a normal operating state.

The thermoswitch 46 may be provided in the engine cooling water or may be provided directly in the fuel in the float chamber of the carburetor to detect its humidity.

FIG. 3 is a schematic sectional view showing still another embodiment of the air vent switching device for a carburetor according to the present invention.

Parts corresponding to the apparatus of FIG. 1 are designated with the same reference numerals.

In this embodiment, a thermobulp 48 is provided in the cooling water 45 of the engine, as in the device shown in FIG.

This thermovalve may be of a type that opens when the temperature is high and closes when the temperature is low.

Now, when the temperature of the engine cooling water 45 becomes high and the thermovalp 48 opens, the atmosphere flows from the atmospheric port 13 to the atmospheric passage 3.
2. Since the inside of the negative pressure pipe 44 is brought to atmospheric pressure through the thermovalve 48, the switching valve 34' closes the inner vent side passage to establish an outer vent state and prevent the occurrence of percolation.

The temperature of the engine cooling water 45 drops and the thermo valve 4
8 closes, the switching valve 34 is closed due to negative pressure in the intake pipe 22.
' closes the outer vent side passage and establishes normal operating conditions.

Other means for connecting the negative pressure pipe 44 to the atmospheric passage 32 to achieve the outer vent state include a carburetor throttle switch, a hydraulic switch, a hydraulic valve, a switch using the voltage generated by a generator, a negative pressure switch, There are switches depending on the engine speed.

As described above, the air vent switching device for a vaporizer according to the present invention is provided with a negative pressure-responsive valve switching device that controls the switching valve for switching between the inner vent and the outer vent in response to conditions that cause a percolation phenomenon. high temperatures or especially no-load/light-load operation,
Alternatively, when the carburetor fuel is exposed to high temperatures such as when the engine is stopped, the negative pressure response switching valve is activated to close the inner vent side passage and establish an outer vent state, thereby reliably preventing the occurrence of percolation.

[Brief explanation of drawings]

1 to 3 are schematic sectional views showing an embodiment of Type B of the air vent switching device for a carburetor according to the present invention. 10... Carburizer, 12... Air passage, 18... Float chamber, 24... Inner vent, 26... Key switch, 30... Solenoid valve, 34... Negative pressure responsive valve switching Actuating device, 34'...Switching valve, 36...Outer vent, 42...Check valve, 46...Thermo switch, 48...Thermo valve.

Claims (1)

[Scope of Claims] 1. An inner vent that communicates between the air passage of the carburetor and the upper part of the float chamber, and an outer vent that communicates the upper part of the float chamber with a canister outside the carburetor, In the air vent switching device for a carburetor, the switching valve is provided with a switching valve that switches between an upper part of the float chamber and only one of the inner vent or the outer vent, wherein the switching valve is a negative pressure responsive valve switching device; The negative end of the valve switching device is communicated with a portion upstream of the venturi of the carburetor air passage through an atmospheric passage, and the atmospheric passage is provided with a valve device that opens the atmospheric passage when the engine is not operating or at high temperature. Further, the negative pressure chamber is connected to the intake pipe downstream of the slot valve by a negative pressure pipe interposed with a check valve that allows only the flow of negative pressure from the negative pressure chamber to the intake pipe. Air vent switching device for vaporizer. 2. The device according to claim 1, wherein the box device is a solenoid valve connected to a key switch or a key switch and a thermoswitch. 3. The device according to claim 1, wherein the box device is a thermobulp.