JPS5885355A - Carburetor's percolation preventing method and device of internal combustion engine - Google Patents

Abstract

PURPOSE:To restrict release of vaporized fuel into atmosphere so as to prevent percolation by extracting fuel inside a float chamber and sending it back to a fuel tank or temporarily holding it in a certain closed reservoir. CONSTITUTION:If an ignition switch 14 is turned off and a manual control valve 24 is opened when the potential formation of percolation appears inside a float chamber 13, a fuel inside the float chamber 13 is sucked through the first conduit 21 into a vacuum tank 30 and the fuel supplied over a specified level inside the tank 30, is fed back by its own weight into a fuel tank 40 through the secondary conduit 22. If the temperature in the float chamber 13 of a carburetor 12 is reduced below a specified value, a thermosensing actuation valve 29 is opened and a vacuum pressure in the vacuum tank 30 is thereby completely released to the atmospheric pressure, on account of which the fuel which is temporarily held inside the vacuum tank 30 is fed back into the float chamber through a branch conduit 27.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and device for preventing percolation in a carburetor in a vehicle internal combustion engine.

Conventionally, a method for preventing the percolation phenomenon in a carburetor is to provide a conduit with one end connected to the upper part of the float chamber of the carburetor and the other end open to the outside air, and to open and close the conduit in conjunction with the opening and closing of the ignition switch of the internal combustion engine. A method has been proposed in which fuel vapor boiled and vaporized in the float chamber is released into the atmosphere through the conduit by opening the on-off valve when the internal combustion engine is stopped using a valve. However, in implementing this method, it is necessary to install a fuel vapor adsorption device in the conduit, and use this adsorption device to adsorb the Hc acid component that causes air pollution, thereby eliminating its release into the atmosphere. . For this reason, an adsorption device having a function of completely separating the HC component is required, which brings about another difficult problem from the viewpoint of pollution prevention.

When the temperature inside the float chamber of the vaporizer rises when the valve is stopped, causing percolation,
The fuel vapor is released into the atmosphere by removing the fuel from the float chamber and returning it to the fuel tank, or by temporarily storing it in a predetermined sealed container and returning it to the float chamber when the temperature inside the float chamber decreases. It is an object of the present invention to provide a method and apparatus for preventing the percolation phenomenon without releasing it, and embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a float chamber 13 of a carburetor 12 installed at the top of an intake manifold 11 of an internal combustion engine has a first valve at its bottom.
One end of conduit 21 is connected.

This first conduit 21 has a vacuum tank 30 at its other end.
The vacuum tank 60 is connected to the bottom of the conduit 6.
1 is connected to an intake manifold 11. Furthermore, one end of a second conduit 22 is connected to a predetermined level position of the vacuum tank 5 30, and the second conduit 22 has the other end connected to the fuel tank 4021 with a first check valve 239, a manually operated valve 24, and a A solenoid valve 25 is provided, a flow control valve 32 is provided in the conduit 31, and a check valve 26 is provided in the second conduit 22.

The first check valve 26 allows fuel to flow from the float chamber 16 to the vacuum tank 60 and blocks fuel flowing in the opposite direction.

The manually operated valve 24 is opened by the operator and normally closed when the vaporizer 12 is in a state where a percolation phenomenon occurs as described below. The electromagnetic valve 25 is energized in response to the opening and closing of the ignition switch 14 of the internal combustion engine, and in the present embodiment, it is energized and closed when the ignition switch 14 is closed, and demagnetized when the switch 14 is opened. and open it. The flow control valve 62 is provided to maintain the vacuum generated in the vacuum tank 30 during operation of the internal combustion engine for a predetermined period of time after the engine is stopped, and serves to control the air flowing into the vacuum tank 301. The check valve 26 allows fuel to flow from the vacuum tank 60 to the fuel tank 40 and blocks fuel flowing in the opposite direction.

A branch conduit 27 branched from the float chamber 1 has its open end connected to the float chamber 1.
3, and this branch conduit 27 has a second
A check valve 28 and a temperature-sensitive operating valve 29 are interposed. The second check valve 28 allows fuel to flow from the vacuum tank 60 to the float chamber 16 via the electromagnetic valve 25, and blocks fuel flowing in the opposite direction. The temperature-sensitive valve 29 is attached to the peripheral wall of the float chamber 16 and is adjusted to open when the temperature of the float chamber 16 is below a predetermined temperature and close when the temperature exceeds a predetermined temperature. In the figure, reference numeral 41 indicates the fuel tank 40 which is activated when the ignition switch 14 is closed.
The reference numeral 42 indicates an electric pump that pumps up the fuel in the tank, and reference numeral 42 indicates an adjustment device that diverts excess fuel fed to the float chamber 16 to the fuel tank 40 when the pressure of the fuel pumped up by the electric pump 41 reaches a predetermined value. A fuel supply device including an electric pump 41 and a pressure regulating valve 42 is already installed in a conventional vehicle.

In the device of the present invention configured as described above, when the ignition switch 14 is closed, the electric pump 41 is started and the fuel in the fuel tank 40 is supplied to the float chamber 13 of the carburetor 12 via the pressure regulating valve 42. When the internal combustion engine is started, the fuel in the float chamber 13 is atomized by the carburetor 12 and the resulting air-fuel mixture is supplied to the intake manifold 11 . Under this operating condition, when the temperature of the float chamber 16 is below a predetermined temperature, the temperature-sensitive operating valve 29 opens and fuel flows from the float chamber 16 to the branch conduit 27, but this flow is stopped by the second check valve. 28
On the other hand, from the bottom of the float chamber 1S
Fuel flowing into the conduit is shut off by closing the manually operated valve 24. Further, the solenoid valve 25 is kept in a closed state by its excitation, and the vacuum tank 50 has an intake manifold pipe 1.
The vacuum pressure generated in step 1 is applied via the flow control valve 32.

By the way, when the above-mentioned internal combustion engine is operated at a high temperature in summer and its operation is stopped, the temperature of the cooling water of the internal combustion engine and the temperature inside the engine room suddenly rise, causing the carburetor 1
The temperature of the second float chamber 13 gradually rises, and the fuel temperature within the float chamber 13 reaches the boiling point, causing the fuel to vaporize and foam, causing a percolation phenomenon. When there is a possibility that such a situation may occur, the driver should turn off the ignition switch 14.
When the manual operation valve 24 is opened and the float chamber 1
The fuel in the vacuum tank 60 is sucked into the vacuum tank 60 through the first conduit 21, and the fuel that overflows in the vacuum tank 60 to a predetermined level or more is drawn into the second conduit 22 by its own weight.
The fuel is returned to the fuel tank 40 through the fuel tank 40. Note that at this time, the temperature-sensitive valve 29 is in a closed state to cut off fuel flowing back into the float chamber 16 through the branch conduit 27. As a result, the fuel in the float chamber 13 can be removed,
The percolation phenomenon of the vaporizer 12 can be prevented.

Thereafter, when the temperature of the float chamber 15 of the carburetor 12 falls below a predetermined temperature due to natural heat dissipation of the cooling water of the internal combustion engine and natural cooling of the engine compartment, the temperature-sensitive valve 29 opens, and in this state, the temperature-sensitive valve 29 opens. <Since the vacuum pressure in the vacuum tank 30 is completely released to atmospheric pressure, the fuel temporarily stored in the vacuum tank 60 is returned to the float chamber 13 through the branch conduit 27. Then,
When the internal combustion engine is restarted by turning on the ignition switch 14 , the electric pump 41 is started and the fuel in the fuel tank 40 is pumped up and sent to the float chamber 1 via the pressure regulating valve 42 .
3. In addition, at this restart, manual operation valve 2
4 is closed by the driver, and the solenoid valve 25 is energized and closed in response to the turning on of the ignition switch 14.

In the above embodiment, when the internal combustion engine is stopped, the first conduit 2
The first check valve 23 and the solenoid valve 25 serve as means for communicating the first check valve 23 and the solenoid valve 25.
Although an example in which a manually operated valve 24 was interposed between the two was explained,
This may be implemented by employing a temperature sensitive valve 124 instead of the manually operated valve 24 as shown in FIG. in this case,
The temperature-sensitive operating valve 124 is attached to the bottom peripheral wall of the float chamber 13 and is adjusted to open when the temperature of the float chamber 16 rises to a predetermined temperature that causes the above-mentioned percolation phenomenon, and close when the temperature falls below the same temperature. be done.

As a result, the fuel in the float chamber 16 is sucked into the vacuum tank 30 in a timely manner without any intervention by the driver. Since the other configurations and operations are essentially the same as those of the embodiment shown in FIG. 1, the same parts are given the same reference numerals and the explanation thereof will be omitted.

Further, in the above embodiment, the fuel stored in the vacuum tank 30 is passed through the branch pipe 27 to the float chamber 16.
Although an example in which the branch pipe 27 and the second check valve 28 attached thereto have been described, the branch pipe 27 and the second check valve 28 . The fuel stored in the vacuum tank 30 may be sequentially returned to the fuel tank 40 through the second conduit 22 without providing the temperature-sensitive valve 29. In this case, even if the inside of the float chamber 13 is temporarily empty, the fuel in the fuel tank 40 is quickly supplied into the float chamber 13 by starting the electric pump 41 when the internal combustion engine is restarted. It does not cause any hindrance.

Furthermore, in carrying out the present invention, in each embodiment shown in FIGS. 1 and 2, the second conduit 22 and the check valve 26 attached thereto are not provided, and the vacuum tank 6
It is also possible to temporarily store all the fuel in the float chamber 13 in the fuel tank o and return it to the float chamber 13 through the branch conduit 27.

As can be understood from the above explanation, the present invention is applicable when the internal combustion engine is stopped and the temperature of the carburetor attached to the internal combustion engine reaches a predetermined temperature or higher (in a state where the percolation phenomenon occurs). ), the fuel in the float chamber of the carburetor is sucked into a vacuum tank connected to the intake pipe of the internal combustion engine and returned to the fuel tank, or the temperature of the carburetor falls below a predetermined temperature. The purpose of the present invention is to provide a method and device for preventing percolation in a vaporizer, characterized in that the percolation is returned to the float chamber when the fuel vapor is released into the atmosphere, thereby avoiding air pollution caused by the release of fuel vapor into the atmosphere. The fuel in the float chamber can be removed, and the percolation phenomenon of the carburetor can be reliably prevented.

[Brief explanation of the drawing]

1 and 2 are piping diagrams schematically showing the method and apparatus of the present invention. Explanation of symbols 11... Intake manifold, 12... Carburetor, 16...
7tff-) chamber, 14... ignition switch, 21...
First conduit, 22... Second conduit, 26... First check valve, 24... Manual operation valve, 25... Solenoid valve, 26th...
Check valve, 27... Branch conduit, 28... Second check valve,
29... Temperature-sensitive operating valve, 30... Vacuum tank,
31... Conduit, 32... Flow rate control valve, 4o... Fuel tank. Applicant Toyota Motor Sales Co., Ltd. Agent Patent Attorney Teru Hase −

Claims (1)

[Scope of Claims] 1) When the internal combustion engine is stopped and the temperature of the carburetor attached to the internal combustion engine reaches a predetermined temperature or higher, the fuel in the float chamber of the carburetor is transferred to the intake air of the internal combustion engine. A method for preventing percolation in a vaporizer, characterized by sucking into a percolumn tank connected to a pipe and returning it to a fuel tank. 2) When the internal combustion engine is stopped and the temperature of the carburetor attached to the internal combustion engine reaches a predetermined temperature or higher, the fuel in the float chamber of the carburetor is transferred to the vacuum tank connected to the intake and trachea of the internal combustion engine. The percolation prevention power of the carburetor is characterized in that the vaporizer is sucked into the air and returned to the float chamber when the temperature of the vaporizer falls below a predetermined temperature.8) Flow rate control in the intake pipe of an internal combustion engine. a first conduit connected via a valve to a L7'C vacuum tank; one end connected to the bottom of the vacuum tank; and the other end connected to the bottom of a float chamber of a carburetor installed in the internal combustion engine; and the vacuum tank. a second conduit having one end connected to a predetermined level position and the other end connected to the fuel tank; and an ignition switch interposed in the first conduit, the energization of which is controlled in response to opening and closing of the ignition switch of the internal combustion engine. an electrically actuated valve interposed in the first conduit upstream of the electrically actuated valve that interrupts fuel flow from the float chamber to the vacuum tank when the ignition switch is closed and allows it when the ignition switch is opened; and valve means for closing the first conduit when the temperature of the vaporizer is below a predetermined temperature and opening the first conduit when the temperature reaches a predetermined temperature or higher. Anti-percolation device. 4) The electrically operated valve is a solenoid valve. 5) The valve means is a temperature-sensitive operated valve attached to the peripheral wall of the float chamber. The device according to claim 3, characterized in that: 6) The apparatus according to claim 3, wherein a manually operated on-off valve is employed as the valve means. 7) A vacuum tank connected to the intake pipe of the internal combustion engine via a flow control valve, one end of which was connected to the bottom of the vacuum tank, and the other end was connected to the bottom of the float chamber of a carburetor installed in the internal combustion engine. a first conduit, a first check valve interposed in the first conduit that allows fuel to flow from the float chamber to the vacuum tank and blocks fuel flowing in the opposite direction; Electricity interposed in the first conduit between 22 and 22, which cuts off communication with the first conduit when the ignition switch of the internal combustion engine is closed and allows communication with the first conduit when the ignition switch is opened; a branch conduit branching from the first conduit between the electrically operated valve and the first check valve and having an open end connected to the upper part of the float chamber; a second check valve interposed therebetween that allows fuel to flow from the vacuum tank to the float chamber and blocks fuel flowing in the opposite direction;
When the temperature of the vaporizer via the conduit reaches a predetermined temperature or higher, fuel is allowed to flow from the float chamber to the vacuum tank through the first check valve and the electrically operated valve, and the temperature of the vaporizer is reduced. valve means that shuts off when the temperature of the carburetor falls below a predetermined temperature; and a valve means that is interposed in the branch conduit to allow fuel to flow into the float chamber through the second check valve when the temperature of the vaporizer reaches a predetermined temperature or higher. A percolation prevention device for a vaporizer, comprising a temperature-sensitive valve that shuts off and allows the vaporizer when the temperature of the vaporizer falls below a predetermined temperature. 8) The apparatus according to claim 7, wherein the valve means is a temperature-sensitive valve attached to the peripheral wall of the vaporizer. 9) The apparatus according to claim 7, wherein the valve means is a manually operated valve.