JP6308640B1 - Mechanism for preventing carburetor sticking due to residual fuel, carburetor equipped with the mechanism, and internal combustion engine - Google Patents

Abstract

A mechanism capable of preventing a carburetor from sticking due to residual fuel, and a carburetor or an internal combustion engine including the mechanism are provided. An auxiliary chamber 620 whose volume can be changed within a certain range is provided separately from the fuel tank, and the auxiliary chamber 620 and the float chamber 613 of the vaporizer 610 are communicated to increase the volume of the auxiliary chamber 620 when necessary. As a result, the fuel in the float chamber 613 can be sucked and temporarily retracted, and the fuel temporarily retracted into the float chamber 613 can be returned by reducing the volume of the auxiliary chamber 620 when necessary. The fuel cock 650 that controls the supply of fuel from the tank to the carburetor 610 is of a negative pressure type in which the supply of fuel is controlled by a negative pressure, and the fuel cock 650 and the intake pipe of the internal combustion engine are connected to a negative pressure transmission pipe 660. To communicate with each other. [Selection] Figure 1

Description

  The present invention relates to the technical field of internal combustion engines, and more particularly to the technical field of internal combustion engines equipped with a carburetor.

  Even today, carburetors (carburetors) are widely used in so-called small gasoline engines (internal combustion engines) such as generators, lawn mowers, and tillers.

  Since the carburetor is inevitably disposed in the vicinity of the combustion chamber, the fuel stored in the carburetor (float chamber) for vaporization becomes high temperature. There is no problem if it is vaporized as it is to become fuel even at high temperatures. However, when the engine is stopped, the gasoline residing in the carburetor has deteriorated, and if left in the carburetor as it is, there is a problem such as clogging the jet part and making restart difficult. .

  In order to solve such problems, various inventions have been proposed. For example, an invention has been proposed in which fuel remaining in the carburetor after the engine is stopped is returned to the fuel tank by a pump (electric pump and manual pump) (see Patent Document 1).

  There has also been proposed an invention in which the residual fuel in the float chamber is returned to the fuel tank by using the negative pressure generated when the engine is stopped (see Patent Document 2).

  Furthermore, an invention has been proposed in which the residual fuel is sucked up by utilizing the capillary phenomenon, and the sucked-up residual fuel is released to the atmosphere (see Patent Document 3).

JP 2014-152606 A JP-A-8-88247 JP-A-2005-240788

  However, returning the deteriorated residual fuel to the fuel tank as in the inventions described in Patent Documents 1 and 2 is not desirable because it leads to a decrease in the quality of the fuel in the entire fuel tank, though it is diluted.

  In addition, when a pump is used as in the invention described in Patent Document 1, the valve mechanism provided in the interior may be fixed by modified gasoline, and the pump itself may not function (as shown, Patent Document 1 describes that In the described invention, the electric pump and the manual pump are arranged in parallel.)

  Further, as in the invention described in Patent Document 2, when the negative pressure generated by the engine stop is used, the fuel in the float chamber is not always efficiently returned to the fuel tank, and the deteriorated fuel is not always returned to the float chamber. In some cases, it remained.

  Further, if the air is positively released to the atmosphere as in the invention described in Patent Document 3, the fuel that is still usable is discarded, which is a waste of resources and is uneconomical. In addition, the capillaries themselves may become clogged with altered fuel and fail.

  Therefore, the present invention provides a mechanism that can reliably and temporarily remove the residual fuel in the float chamber without returning it to the fuel tank and can prevent the carburetor from sticking due to the residual fuel, and It is an object of the present invention to provide a carburetor or an internal combustion engine equipped with

  In order to solve the above problems, the present invention provides an auxiliary chamber whose volume can be changed within a certain range separately from the fuel tank, and communicates the auxiliary chamber with the float chamber of the vaporizer. By increasing the volume, the fuel in the float chamber is sucked and temporarily retracted, and when necessary, the volume of the auxiliary chamber is reduced to return the temporarily retracted fuel to the float chamber. The fuel cock for controlling the fuel supply from the fuel tank to the carburetor is of a negative pressure type in which the fuel supply is controlled by a negative pressure, and the fuel cock and the intake pipe of the internal combustion engine are connected to each other. A negative pressure transmission pipe communicated is provided.

  By adopting such a configuration, the altered residual fuel can be temporarily removed from the float chamber without returning to the fuel tank. In addition, since the fuel in the float chamber is sucked out to the auxiliary chamber using the negative pressure generated by changing the volume of the auxiliary chamber, the residual fuel can be reliably extracted from the float chamber. Further, a negative pressure type fuel cock is employed, and the fuel cock and the intake pipe are communicated with each other through a negative pressure transmission pipe. That is, when a negative pressure is generated in the intake pipe (the internal combustion engine is in a moving state), the fuel cock is opened and fuel is supplied to the float chamber, and a negative pressure is generated in the intake pipe. When there is no fuel (the internal combustion engine is not moving), the fuel cock is closed and the fuel supply to the float chamber is stopped. In short, since the fuel supply to the float chamber is automatically stopped when the internal combustion engine is stopped, after the internal combustion engine is stopped, the fuel further flows after the residual fuel in the float chamber is moved to the auxiliary chamber side. Can be prevented.

  In addition, the present invention provides an auxiliary chamber whose volume can be changed within a certain range separately from the fuel tank, and integrally forms the auxiliary chamber and the float chamber of the vaporizer. The fuel in the float chamber can be temporarily retracted by increasing the volume, and when necessary, the fuel that has been temporarily retracted into the float chamber can be returned by reducing the volume of the auxiliary chamber. The fuel cock that controls the supply of the fuel from the tank to the carburetor is a negative pressure type in which the fuel supply is controlled by a negative pressure, and the negative pressure in which the fuel cock communicates with the intake pipe of the internal combustion engine A transmission tube is provided.

  The auxiliary chamber is not a separate chamber, but it is possible to achieve the same effect by, for example, forming the float chamber so as to extend downward, and the mechanism can be simpler and more compact. It becomes.

  An operation unit for changing the volume of the auxiliary chamber, the operation unit having a position that changes in accordance with a change in the volume of the auxiliary chamber, is provided in the middle of the negative pressure transmission pipe. An atmosphere release valve capable of communicating between the inside and the outside of the transmission pipe, and the operation portion is mechanically connected to the atmosphere release valve, and the volume of the auxiliary chamber is reduced in the position of the operation portion so that the fuel is floated. In the first position in the chamber, the atmosphere release valve is closed, so that the negative pressure generated in the intake pipe can be transmitted to the fuel cock via the negative pressure transmission pipe, and the position of the operation portion is In the second position where the volume of the auxiliary chamber is increased and the fuel is withdrawn from the float chamber, the air release valve is opened and the negative pressure generated in the intake pipe is cut off at least to the extent that the fuel cock is closed. Negative pressure blocking mechanism Characterized in that it comprises.

  If comprised in this way, it will become possible to shut off the negative pressure of a negative pressure transmission pipe automatically, and to close a fuel cock by operating the operation part of an auxiliary chamber. That is, when the position of the operating portion is in the first position (when the fuel is in the float chamber), the negative pressure in the negative pressure transmission pipe transmitted from the intake pipe is transmitted to the fuel cock without any problem. The cock opens and fuel is supplied to the float chamber. On the other hand, when the position of the operation unit is in the second position (when the fuel is not in the float chamber), the negative pressure in the negative pressure transmission pipe is blocked by the inflow of air from the atmosphere release valve. That is, the fuel cock is closed and the fuel supply to the float chamber is stopped. Therefore, even if the operation part of the auxiliary chamber is operated (operation to move the fuel in the float chamber to the auxiliary chamber side) without stopping (moving) the internal combustion engine, the float It is possible to reliably prevent the fuel from being continuously supplied to the chamber. Furthermore, since the fuel supply itself is stopped by the operation of the operation unit, it is possible to also use a mechanism for stopping the internal combustion engine.

  In addition, there is provided a changing point where the opening and closing of the fuel cock changes during the transition of the operating unit from the first position to the second position, and the operating unit is moved from the changing point to the second position. A delay means for delaying the time to move to the position is provided.

  Thus, if the opening / closing of the fuel cock is changed (opening of the atmosphere release valve) during the transition of the operating unit from the first position to the second position, the residual fuel is assisted. It is possible to more reliably prevent fuel from being supplied to the float chamber after it has been evacuated to the chamber, and at the time of restart, when the fuel evacuated to the auxiliary chamber is returned to the float chamber, fuel overflows from the float chamber It can be prevented from going out. In addition, by providing the delay means, it is possible to more efficiently move the fuel that can be supplied until the position of the operation unit reaches the changing point to the auxiliary chamber side.

  Further, the delay means is realized by setting the change point as close to the first position as possible.

  With this configuration, the delay means can be configured without providing any other parts or mechanisms. That is, “the change point is close to the first position” means that “the change point is far from the second position” at the same time, so the delay means is configured by this physical distance. is there.

  The delay unit includes a guide unit that guides movement when the operation unit shifts from the first position to the second position, and the operation unit moves from the change point to the second position. In the middle of reaching the position, the shape guided by the guide portion is realized by forming a crank shape or a hook shape.

  With this configuration, when operating the operation unit from the change point to the second position, it is necessary to move the operation in a crank shape or a hook shape, so that the operation is delayed by the time required for this movement. It will be done.

  In addition, the delay unit is configured to increase an operation load of the operation unit from the change point to the second position larger than an operation load of the operation unit from the first position to the change point. It is special that it is realized by doing.

  If comprised in this way, operation of an operation part itself can implement | achieve a delay means with a simple motion. Further, if the load can be varied, the delay time can be adjusted according to the operator.

  From a different point of view, the present invention can also be understood as a carburetor or an internal combustion engine having the carburetor adhering prevention mechanism.

  By applying the present invention, the residual fuel in the float chamber can be reliably and temporarily removed without being returned to the fuel tank and can be reused, and the carburetor can be prevented from being stuck by the residual fuel. And a carburetor or an internal combustion engine including the same.

It is the schematic block diagram of the vaporizer sticking prevention mechanism shown as an example of embodiment of this invention, Comprising: It is the figure which showed the state which has a fuel in a float chamber. It is a schematic block diagram of the vaporizer sticking prevention mechanism shown as an example of embodiment of this invention, Comprising: It is the figure which showed the state which has a fuel in an auxiliary chamber. It is a schematic block diagram of the vaporizer sticking prevention mechanism provided with the air release valve shown as 2nd Example, Comprising: It is the figure which showed the state (atmosphere release valve closed) which has a fuel in a float chamber. It is a schematic block diagram of the vaporizer sticking prevention mechanism provided with the atmospheric release valve shown as 2nd Example, Comprising: It is the figure which showed the state (atmospheric release valve open) which has a fuel in an auxiliary | assistant chamber. It is the schematic block diagram which showed the structural example of the delay means.

  Hereinafter, a vaporizer sticking prevention mechanism 600 as an example of an embodiment of the present invention will be described with reference to the accompanying drawings. For easy understanding of the drawings, it should be noted that there are portions where the size and dimensions of each portion are exaggerated and there are portions that do not necessarily match the actual product. In addition, each drawing is viewed in the direction of the reference sign, and is expressed as upper, lower, left, right, near, and back based on the direction.

<Configuration of vaporizer sticking prevention mechanism>
As shown in FIGS. 1 and 2, the carburetor sticking prevention mechanism 600 shown as an example of the embodiment of the present invention includes an auxiliary chamber 620 connected to the carburetor 610 and a negative pressure fuel cock 650 as main components. Function as. Although not shown, the carburetor 610 and the auxiliary chamber 620 are provided in the internal combustion engine.

  The carburetor 610 is provided in the middle of an air passage 611 through which intake air passes from an air cleaner (not shown) to a combustion chamber (not shown). A throttle 612 is provided in the air passage 611. A float chamber 613 having a float 614 is attached below the air passage 611. A part of the air passage 611 includes a venturi portion with a reduced diameter. A jet needle 615 connected from the float chamber 613 is arranged to protrude from the venturi section. A float chamber fuel inlet 617 is provided above the side surface of the float chamber 613. A fuel cock 650 is connected to the float chamber fuel introduction port 617. The fuel cock 650 is connected to the float chamber 613 by a fuel pipe 602. Fuel cock 650 is also connected to a fuel tank (not shown). In other words, when the fuel cock 650 is opened, the fuel is configured to flow to the float chamber 613 via the fuel pipe 602. When the amount of fuel in the float chamber 613 becomes an appropriate amount, the valve 616 provided in the float 614 blocks the float chamber fuel inlet 617 and the fuel inflow stops. The fuel cock 650 is connected to an intake pipe (intake manifold) of the internal combustion engine by a negative pressure transmission pipe 660. The fuel cock 650 is in a state where a predetermined negative pressure is generated in the negative pressure transmission pipe 660. The fuel cock 650 is configured to be opened and closed with no predetermined negative pressure.

  A float chamber fuel escape port 618 is provided on the bottom surface of the float chamber 613. A fuel pipe 604 is connected to the float chamber fuel retraction port 618, and the other end of the fuel pipe 604 is connected to the connection port 623 of the auxiliary chamber 620.

  The auxiliary chamber 620 includes a so-called displacement film (diaphragm) 622, and the volume in the auxiliary chamber 620 can be changed by operation. The auxiliary chamber 620 has an outer side constituted by a casing 621 having appropriate rigidity, and can take in the residual fuel G into the casing 621. A displacement film 622 is provided in the casing 621. The outer periphery of the displacement film 622 is fixed to the casing 621. On the other hand, the portions other than the outer periphery of the displacement film 622 are not fixed to the casing 621, and can move while being displaced in the vertical direction. . That is, the inside of the casing 621 is partitioned into two upper and lower rooms by the displacement film 622. The lower room is provided with a connection port 623 and communicates with the float chamber 613 via a fuel pipe 604.

  A through hole 621a is provided in the approximate center of the upper surface of the casing 621, and a biasing rod 625 is passed through the through hole 621a. An urging plate 624 is attached to the lower end of the urging rod 625, and the urging plate 624 is further bonded and fixed to the displacement film 622. That is, when the biasing rod 625 moves up and down, the displacement film 622 moves up and down in conjunction with each other.

  The upper end of the biasing rod 625 is connected to the vicinity of the approximate center of the operation lever 627 by a pin 640. One end of the operation lever 627 is pivotally supported via a pin 641 from a rotation support base 626 fixed to the casing 621. In other words, when the operation lever 627 is pushed up, the displacement film 622 is raised through the biasing rod 625 and the volume in the auxiliary chamber 620 is increased. On the other hand, when the operation lever 627 is pushed down, the displacement film 622 is lowered via the biasing rod 625 and the volume in the auxiliary chamber 620 is reduced. At this time, it is also possible to adopt a configuration in which a slight gap is generated between the displacement film 622 and the casing 621 even when the displacement film 622 is lowered. By doing so, sticking by the modified gasoline (sticking of the displacement film 622 and the casing 621) can be prevented.

<Function and function of vaporizer sticking prevention mechanism>
The operations will be described in order on the assumption that the residual fuel G in the float chamber 613 is retracted to the auxiliary chamber 620 at the time of previous use.

[Operation procedure when starting the internal combustion engine]
In order to start the internal combustion engine, the fuel cock 650 needs to be opened. However, since the fuel cock in the present invention is a negative pressure type, no special operation is required.

  Therefore, as shown in FIG. 1, it is necessary to push down the operation lever 627 of the auxiliary chamber 620 to push the previous residual fuel G in the auxiliary chamber 620 to the float chamber 613 side.

  Thereafter, when the internal combustion engine is started manually or by a starter, a negative pressure is generated on the intake pipe side by the movement. The generated negative pressure is transmitted to the fuel cock 650 via the negative pressure transmission pipe 660, the fuel cock 650 is opened, and fuel is supplied to the float chamber 613.

[Operation procedure when stopping the internal combustion engine]
Subsequently, an operation of retracting the residual fuel G in the float chamber 113 to the auxiliary chamber 120 after the internal combustion engine is stopped will be described.

  When the internal combustion engine is stopped, the negative pressure in the negative pressure transmission pipe 660 disappears (or decreases) in conjunction with it, so the fuel cock 650 is closed and the supply of fuel from the fuel tank to the float chamber 613 is stopped. On the other hand, the residual fuel G that has not been vaporized remains in the float chamber 613, and if left as it is, there is a concern that the jet needle 615 may be clogged due to alteration or the like. Therefore, the residual fuel G in the float chamber 613 is retracted to the auxiliary chamber 620 side by pulling up the operation lever 627.

  As described above, in the present invention, the auxiliary chamber 620 whose volume can be changed within a certain range is provided separately from the fuel tank, the auxiliary chamber 620 and the float chamber 613 of the vaporizer 610 are communicated, and the auxiliary chamber 620 is used when necessary. The fuel in the float chamber 613 is sucked and temporarily retracted by increasing the volume of the auxiliary chamber 620, and the fuel temporarily retracted in the float chamber 613 is returned by reducing the volume of the auxiliary chamber 620 when necessary. The fuel cock 650 that controls the supply of fuel from the fuel tank to the carburetor 610 is of a negative pressure type in which the supply of fuel is controlled by a negative pressure, and the fuel cock 650 and the intake pipe of the internal combustion engine are connected to each other. A negative pressure transmission pipe 660 was provided.

  By adopting such a configuration, the altered residual fuel can be temporarily removed from the float chamber 613 without returning it to the fuel tank. Further, since the fuel in the float chamber 613 is sucked out to the auxiliary chamber 620 using the negative pressure generated by changing the volume of the auxiliary chamber 620, the residual fuel can be reliably extracted from the float chamber 613. Further, a negative pressure type fuel cock 650 is employed, and the fuel cock 650 and the intake pipe are communicated with each other by a negative pressure transmission pipe 660. That is, when negative pressure is generated in the intake pipe (the internal combustion engine is in a moving state), the fuel cock 650 is opened and fuel is supplied to the float chamber 613, and negative pressure is generated in the intake pipe. The fuel cock 650 is closed when the internal combustion engine is not moving, and the fuel supply to the float chamber 613 is stopped. In short, since the fuel supply to the float chamber 613 is automatically stopped when the internal combustion engine is stopped, after the internal combustion engine is stopped, the fuel is moved after the residual fuel in the float chamber 613 is moved to the auxiliary chamber 620 side. Further, the supply to the float chamber 613 can be prevented.

  Although not shown, the auxiliary chamber can be formed integrally with the float chamber. Specifically, for example, an auxiliary chamber is provided below the float chamber (compared with the above-described embodiment, the auxiliary chamber is integrated so as to be upside down), and by pulling down the displacement film, The configuration is such that the residual fuel in the float chamber is moved to the auxiliary chamber side.

  As described above, the auxiliary chamber is not formed as a separate chamber, but is formed integrally with the float chamber so as to extend downward (similar to the above-described vaporizer sticking prevention mechanism 600), the same effect can be exhibited. At the same time, a simpler and more compact structure is possible as the mechanism.

  In the above description, the displacement film (diaphragm) is used as an example to change the volume of the auxiliary chamber. However, the present invention is not limited to this. For example, it may be an auxiliary chamber whose volume changes depending on the piston structure.

  Furthermore, the operation lever for displacing the displacement film is not limited to the above-described embodiment, and a different configuration can be adopted.

<Configuration of Second Embodiment with Atmospheric Release Valve>
Next, as shown in FIGS. 3 to 4, a vaporizer sticking prevention mechanism 700 having an atmosphere release valve 780 will be described as a second embodiment. In addition, about the part which is the same as that of the above-mentioned vaporizer sticking prevention mechanism 600, only the last two digits attach the same code | symbol, suppose that duplication description is abbreviate | omitted and demonstrates below focusing on a different part. .

  The vaporizer sticking prevention mechanism 700 is different from the above-described vaporizer sticking prevention mechanism 600 in that an air release valve 780 is provided in the middle of the negative pressure transmission pipe 760, and an operation lever (of the air release valve 780 and the auxiliary chamber 720 ( The operation portion 727 is provided with a negative pressure blocking mechanism 701 mechanically connected by a wire 731.

  The air release valve 780 is provided with a release hole 782a in the main body 782, and the plug 784 is constantly urged by the negative force of the spring 786 with respect to the release hole 782a, and the internal sealing performance is maintained. It is configured as follows. The plug 784 is connected to one end of an operation lever (operation unit) 727 via a wire attachment portion 736 by a wire 731. As a result, the atmosphere release valve 780 is closed at the first position (the state shown in FIG. 3) in which the position of the operation lever 727 is reduced in the volume of the auxiliary chamber 720 and the fuel is present in the float chamber 713 (that is, The plug body 784 is in contact with the release hole 782a), and the negative pressure generated in the intake pipe is transmitted to the fuel cock 750 via the negative pressure transmission pipe 760. On the other hand, the air release valve 780 is open at the second position (state of FIG. 4) in which the position of the operation lever 727 increases the volume of the auxiliary chamber 720 and retracts the fuel from the float chamber 713 (that is, The plug body 784 is not in contact with the release hole 782a), and the negative pressure generated in the intake pipe is cut off at least to the extent that the fuel cock 750 is closed (that is, the atmosphere is released from the atmosphere release valve 780 into the negative pressure transmission pipe 760). The negative pressure is cut off by flowing in.)

  With this configuration, by operating the operation lever (operation unit) 727 of the auxiliary chamber 720, it is possible to automatically shut off the negative pressure of the negative pressure transmission pipe 760 and close the fuel cock 750. ing. That is, when the operation lever 727 is in the first position (when the fuel is in the float chamber 713), the negative pressure in the negative pressure transmission pipe 760 transmitted from the intake pipe causes a problem to the fuel cock 750. The fuel cock 750 is opened and the fuel is supplied to the float chamber 713. On the other hand, when the operation lever 727 is in the second position (when the fuel is not in the float chamber 713), the negative pressure in the negative pressure transmission pipe 760 is blocked by the inflow of the atmosphere from the atmosphere release valve 780. Is done. That is, the fuel cock 750 is closed and the fuel supply to the float chamber 713 is stopped. Therefore, the operation lever 727 of the auxiliary chamber 720 is operated (operation for moving the fuel in the float chamber 713 to the auxiliary chamber 720 side) in a state where the internal combustion engine is not stopped (the state where the internal combustion engine is moved). Even in the case where it has been, it is possible to reliably prevent the fuel from being continuously supplied to the float chamber 713. Further, since the fuel supply itself is stopped by operating the operation lever 727, a mechanism for stopping the internal combustion engine can also be used.

  Further, as schematically shown in FIG. 5, a change point γ at which the opening and closing of the fuel cock 750 changes is provided during the transition of the operation lever 727 from the first position α to the second position β. In addition, it is desirable to further include a delay means for delaying the time for the operation lever 727 to move from the change point γ to the second position β.

  In this way, if the opening / closing of the fuel cock 750 is changed (opening of the air release valve 780) during the transition of the operation lever 727 from the first position α to the second position β, the residual When the fuel G is retracted to the auxiliary chamber 720, it is possible to more reliably prevent the fuel from being supplied to the float chamber 713. When restarting, the fuel retracted to the auxiliary chamber 720 is returned to the float chamber 713. In addition, it is possible to prevent the fuel from overflowing from the float chamber 713. At that time, by setting the position of the change point γ as close as possible to the first position α, the amount of fuel that can be supplied until the operation lever 727 reaches the change point γ is reduced. be able to. In addition, since the delay unit is provided, the operation unit 727 is moved to the second position even after the fuel supply is stopped, so that the fuel that has been supplied to the float chamber 713 is floated. It is possible to move to the auxiliary room 720 side without leaving as much as possible in the room 713.

  The delay means can also be realized by setting the change point γ as close to the first position α as possible. In this way, the delay means can be configured without providing any other parts or mechanisms. That is, “the change point γ is close to the first position α” means that “the change point γ is far from the second position β”. Therefore, the delay unit is configured by this physical distance. To do.

  Further, as shown in FIG. 5, for example, a guide portion 790 having a guide groove 792 in which a part of the operation lever 727 is fitted and the movement thereof is guided is provided in the middle (from the change point γ to the second point The delay means can also be configured by providing a crank portion 794, for example, in the middle of shifting to the position β.

  Although not shown, the operation load of the operation lever 727 between the change point γ and the second position β is larger than the operation load of the operation lever 727 between the first position α and the change point γ. By doing so, the delay means can be configured. At this time, the load may be variable.

  With this configuration, when operating the operation lever 727 from the change point γ to the second position β, it is necessary to move the operation in a crank shape or a hook shape, so that only the time required for this movement is required. The operation will be delayed.

600 ... Vaporizer sticking prevention mechanism 602, 604 ... Fuel pipe 610 ... Vaporizer 611 ... Air path 612 ... Throttle 613 ... Float chamber 614 ... Float 615 ... Jet Needle 616 ... Valve 617 ... Float chamber fuel inlet 618 ... Float chamber fuel outlet 620 ... Auxiliary chamber 621 ... Casing 621a ... Through hole 622 ... Displacement membrane (diaphragm)
623 ... Connection port 624 ... Biasing plate 625 ... Biasing rod 626 ... Rotation support base 627 ... Operation lever 630 ... Lock member 631 ... Wire 650 ... Fuel cock 701 ... Negative pressure blocking mechanism 780 ... Air release valve 790 ... Guide plate 792 ... Guide groove 794 ... Crank part G ... Fuel

Claims (8)

Apart from the fuel tank, there is an auxiliary chamber whose volume can be changed within a certain range,
The auxiliary room communicates with the float chamber of the vaporizer,
When necessary, the volume of the auxiliary chamber is increased to suck in the fuel in the float chamber and temporarily retreat,
When necessary, the temporarily retracted fuel can be returned to the float chamber by reducing the volume of the auxiliary chamber,
After making the fuel cock that controls the supply of the fuel from the fuel tank to the carburetor a negative pressure type in which the supply of the fuel is controlled by a negative pressure,
A negative pressure transmission pipe that communicates the fuel cock with the intake pipe of the internal combustion engine ;
Furthermore, an operation unit for changing the volume of the auxiliary chamber, the operation unit having a position that changes in accordance with a change in the volume of the auxiliary chamber,
In the middle of the negative pressure transmission pipe, an atmospheric release valve capable of communicating the inside and outside of the negative pressure transmission pipe is provided,
The operation unit is mechanically connected to the atmosphere release valve,
In the first position where the volume of the auxiliary chamber is reduced and the fuel is in the float chamber, the atmosphere release valve is closed and the negative pressure generated in the intake pipe is transmitted to the negative pressure. The atmosphere release valve can be transmitted to the fuel cock via a pipe, and in the second position where the volume of the auxiliary chamber is increased and the fuel is withdrawn from the float chamber. A carburetor adhering prevention mechanism comprising a negative pressure shut-off mechanism capable of shutting off the negative pressure generated in the intake pipe at least to the extent that the fuel cock is closed . Apart from the fuel tank, there is an auxiliary chamber whose volume can be changed within a certain range,
The auxiliary chamber and the float chamber of the vaporizer are integrally formed,
When necessary, the fuel in the float chamber is temporarily withdrawn by increasing the volume of the auxiliary chamber,
When necessary, the fuel temporarily retracted into the float chamber can be returned by reducing the volume of the auxiliary chamber,
After making the fuel cock that controls the supply of the fuel from the fuel tank to the carburetor a negative pressure type in which the supply of the fuel is controlled by a negative pressure,
E Bei negative pressure transmission tube communicated with the intake pipe of the fuel cock and the internal combustion engine,
Furthermore, an operation unit for changing the volume of the auxiliary chamber, the operation unit having a position that changes in accordance with a change in the volume of the auxiliary chamber,
In the middle of the negative pressure transmission pipe, an atmospheric release valve capable of communicating the inside and outside of the negative pressure transmission pipe is provided,
The operation unit is mechanically connected to the atmosphere release valve,
In the first position where the volume of the auxiliary chamber is reduced and the fuel is in the float chamber, the atmosphere release valve is closed and the negative pressure generated in the intake pipe is transmitted to the negative pressure. The atmosphere release valve can be transmitted to the fuel cock via a pipe, and in the second position where the volume of the auxiliary chamber is increased and the fuel is withdrawn from the float chamber. A carburetor adhering prevention mechanism comprising a negative pressure shut-off mechanism capable of shutting off the negative pressure generated in the intake pipe at least to the extent that the fuel cock is closed . In claim 1 or 2 ,
In the middle of the operation unit moving from the first position to the second position, there is provided a changing point where the opening and closing of the fuel cock changes,
A carburetor adhering prevention mechanism, comprising delay means for delaying a time for the operation unit to move from the change point to the second position. In claim 3 ,
The delay unit is realized by setting the change point as close to the first position as possible. In claim 3 ,
The delay unit includes a guide unit that guides movement when the operation unit moves from the first position to the second position, and the operation unit moves from the change point to the second position. It is realized by configuring the shape guided by the guide portion on the way to the shape of a crank or a hook.
A vaporizer sticking prevention mechanism characterized by that. In claim 3 ,
The delay means makes an operation load of the operation unit from the change point to the second position larger than an operation load of the operation unit from the first position to the change point. A vaporizer sticking prevention mechanism characterized by being realized by the following.   The vaporizer provided with the vaporizer sticking prevention mechanism in any one of Claims 1-6. An internal combustion engine comprising the carburetor according to claim 7 .

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