JP4174457B2 - Engine fuel supply system - Google Patents

Description

  The present invention relates to an engine fuel supply apparatus, and more particularly to an engine fuel supply apparatus that allows a float chamber of a carburetor to be easily drained when the engine is stored for a long period of time.

  2. Description of the Related Art Conventionally, an engine fuel supply apparatus in an agricultural machine or the like is configured to include an engine carburetor having a float chamber, a fuel tank, a fuel pump using a negative pressure type structure, and a path switching means. Specifically, the fuel pump and the path switching means are connected to the fuel supply / discharge path connecting the carburetor and the fuel tank, and the fuel from the fuel tank is supplied by the operation of the fuel pump by the switching operation of the path switching means. The operation state supplied to the carburetor and the recirculation state in which the fuel remaining in the float chamber is returned to the fuel tank by the operation of the fuel pump are configured to be switchable. As such a technique, the one disclosed in Patent Document 1 is known. The reason why the fuel supply device can perform a recirculation state in which the fuel accumulated in the carburetor is returned to the fuel tank is as follows.

  Agricultural machines such as management machines and rice transplanters have a relatively short operation period, and are stored in a warehouse or the like for a long time in the agricultural off-season. Therefore, in an engine mounted on a machine with strong seasonality such as an agricultural machine, the fuel stored in the float in the carburetor (carburetor) deteriorates during the off-season (the volatile components are lost and gummed, In some cases, the engine may not be suitable for combustion), and in the next season, starting failure, hunting, etc. may occur. In order to prevent this problem, the user is instructed and asked to remove the residual fuel from the drain port provided in the float chamber when not in use. However, the operation is bothersome or forgotten. The fact is not being done.

In order to solve this problem, as disclosed in the above-mentioned Patent Document 1, by providing the fuel supply / discharge path with a path switching means for switching between the operating state and the recirculation state, when the use is stopped for a long time. By switching the path switching means to the reflux state and returning the residual fuel in the float chamber to the fuel tank, the fuel in the carburetor can be prevented from deteriorating, and problems such as starting failure in the next season can be prevented. In addition, since the residual fuel is returned to the fuel tank, it is desirable that it is less wasteful and more economical than the means for discharging to the outside.
Japanese Patent Laid-Open No. 7-317619

  By adopting the technique disclosed in Patent Document 1 mentioned above, it is possible to easily return the residual fuel in the carburetor to the fuel tank by switching operation of the path switching means (flow path switching tool). It became. However, in the prior art, it has been found that there are places where the fuel cannot be recirculated even when switched to the recirculation state. That is, referring to FIG. 2 of Patent Document 1, the fuel existing in the fuel supply path 6 connecting the flow path switching tool 8 serving as the path switching means and the float chamber inlet 5a of the vaporizer 4 is the fuel tank 1. It cannot be returned to. This is because in the recirculation state, the first flow path 10 connected to the fuel supply path 6 in the flow path switching tool 8 is closed, so that the suction action of the fuel pump 3 does not reach the fuel supply path 6. The cause is.

  Therefore, even if the remaining fuel is returned to the fuel tank by switching to the recirculation state, fuel still remains in the fuel supply path connecting the flow path switching tool and the carburetor, which deteriorates during the season off. As a result, there is still room for further improvement because it may cause the above-mentioned problems in the next season.

  In view of such circumstances, the object of the present invention is to conveniently select and switch between an operation state for operating the engine and a recirculation state for removing the fuel in the carburetor and returning it to the fuel tank. The fuel supply device is provided so as to be improved so that a higher effect can be obtained by allowing the fuel supply device to be in a state where no residual fuel is generated in the reflux state.

According to the first aspect of the present invention, a fuel pump 5B and a path switching means 5A are connected to a fuel supply / discharge path 2 that connects an engine carburetor 3 having a float chamber 4 and a fuel tank 1, and the path switching means. An operation state in which the fuel from the fuel tank 1 is supplied to the carburetor 3 by the operation of the fuel pump 5B by the switching operation of 5A, and the residual fuel in the float chamber 4 is supplied to the fuel tank by the operation of the fuel pump 5B. In the engine fuel supply device configured to be switchable between a reflux state to be returned to 1,
In the operating state, the fuel discharged from the fuel pump 5B is supplied to the float chamber 4 via the path switching means 5A and a supply path h1 connecting the same with the vaporizer 3, and in the reflux state. Is configured such that residual fuel in the float chamber 4 is sucked into the fuel pump 5B via the path switching means 5A and a discharge path h2 connecting the same and the vaporizer 3, and the path switching means 5A. In addition, an air release path 40 for opening the supply path h1 to the atmosphere only in the reflux state is provided.

  According to a second aspect of the present invention, in the engine fuel supply device according to the first aspect, the path switching means 5A communicates with the valve body block 15 having a movable valve body 16 that can be switched and connected to the supply path h1. A first supply / discharge port p1, a second supply / discharge port p2 communicating with the discharge passage h2, and a plurality of supply / discharge ports p3 to p6 corresponding to the fuel pump 5B and the fuel tank 1 The movable valve body 16 is configured so as to be opened to the first supply / exhaust port p1 only when the movable valve body 16 is switched to the reflux state. It is the external communication hole formed in the predetermined location.

According to a third aspect of the present invention, in the fuel supply device for an engine according to the second aspect, the plurality of supply / discharge ports p3 to p6 are connected to the fuel tank 1 through third and fourth supply / discharge ports p3 and p4. And a discharge port p5 communicating with the discharge port 21 of the fuel pump 5B, and a suction port p6 communicating with the suction port 22 of the fuel pump 5B,
When the movable valve body 16 is switched to the operating position, the fourth supply / discharge port p4 and the suction port p6 are communicated, and the first supply / discharge port p1 and the discharge port p5 are communicated. When the state is obtained and the movable valve body 16 is switched to the return position, the suction port p6 and the second supply / discharge port p2 communicate with each other, and the discharge port p5 and the third supply / discharge port p3 It is comprised so that the said recirculation | reflux state which can communicate can be obtained.

  According to the configuration of the first aspect of the present invention, the atmosphere switching path for opening the supply path to the atmosphere open state is provided in the path switching means only in the reflux condition. Therefore, in the reflux condition, the supply path connecting the path switching means and the vaporizer is provided. The atmosphere can enter (corresponding to the above-described fuel supply path), whereby the intake action of the fuel pump can be extended to the supply path via the float chamber. And in an operating state, since the atmosphere open path does not have influence, the fuel of a fuel tank can be satisfactorily supplied to a carburetor without trouble. As a result, it is possible to reduce the fuel existing in the supply channel that could not be removed in the past to the fuel tank, and in the recirculation state, no residual fuel can be generated, which is a good engine for the next season. It is possible to provide an engine fuel supply device that can obtain the effect of starting at a higher level.

  According to the second and third aspects of the present invention, the switching valve is composed of a valve passage block and a valve body block to which the path switching means is connected to the fuel tank, the carburetor, and the fuel pump. In the case of a structure, it is only necessary to form an external communication hole in the movable valve body that communicates with the first supply / exhaust port connected to the supply path only in the recirculation state, without additional parts, and Thus, it is possible to obtain an engine fuel supply device that has a simple structure and no remaining fuel.

  Hereinafter, a case where an embodiment of the present invention is applied to a fuel supply device for a gasoline engine for agricultural machinery such as a management machine will be described with reference to the drawings. FIG. 1 is a schematic system diagram showing an engine fuel supply device, FIGS. 2 to 4 are exploded perspective views of a pump with switching means showing the flow of fuel, FIG. 2 is an operating state, and FIG. 3 is a reflux state. FIG. 4 shows the shut-off state. 5 and 6 are a front view and a side view of the pump with switching means, and FIGS. 7 and 8 are a front view and a side view showing the mounting structure of the pump with switching means and its operating structure.

  As shown in FIG. 1, the engine fuel supply device A according to the first embodiment is provided in a fuel supply / discharge path 2 that connects a gasoline engine E and a fuel tank 1. In other words, the pump with switching means is formed by integrating the fuel pump 5B and the path switching means 5A in the fuel supply / discharge path 2 connecting the engine carburetor (vaporizer) 3 having the float chamber 4 and the fuel tank 1. 5 is connected. The carburetor 3 and the engine E are connected through an intake manifold 11, and an air cleaner 33 (see FIGS. 7 and 8) is connected to the side of the carburetor 3 opposite to the intake manifold 11 mounting side. Note that 6 is an ignition plug, 7 is an ignition circuit, and 8 is an ignition switch that can be rotated by a main key (not shown).

  The fuel supply / discharge path 2 is a first pipe (an example of a supply path) h1 that connects the first supply / discharge port k1 of the pump 5 with switching means and the fuel inlet 4a formed at the upper end of the float chamber 4; A second pipe (an example of a discharge path) h2 connecting the second supply / discharge port k2 of the pump 5 with switching means and the drain port 4b formed at the lower end of the float chamber 4 and a bottom surface of the fuel tank 1 are formed. It is comprised from the single 3rd piping h3 which connects the discharged discharge port 1a and the 3rd supply / discharge port k3 of the pump 5 with a switching means. The third supply / exhaust port k3 may pass through a filter path 13 having a bidirectional filter 12 as indicated by a virtual line in FIG.

  As shown in FIGS. 1 to 6, the pump 5 with switching means is configured such that the fuel pump 5B and the path switching means 5A are integrated. That is, a pump block 14 that functions as a fuel pump 5B, a valve body block 15 having a movable valve body 16 that can be switched and moved, a plurality of supply / discharge ports k1 to k3 for the fuel tank 1 and the carburetor 3, and a pump block 14 And a valve structure comprising a valve passage block 17 in which a plurality of supply / discharge ports p1 to p6 corresponding to the valve body block 15 are formed. More specifically, the valve passage block 17 is integrated between the pump block 14 and the valve body block 15, and a shaft hole 18 a for the operation knob 19 is provided outside the valve body block 15 (see FIG. 6). The cover plate 18 on which is formed) is overlapped and integrated. A thin plate-like gasket 20 is interposed between the valve body block 15 and the valve passage block 17.

  As shown in FIGS. 2 to 5, the valve body block 15 has a stepped circular hole (not shown) that accommodates the movable valve body 16 having a flat cylindrical shape so as to be rotatable about the axis X. It is composed of square block bodies. As shown in FIGS. 5 and 6A and 6B, the movable valve body 16 regulates the rotation range of the stepped cylindrical main body portion 16A and the shaft portion 16a integrally formed with the main body portion 16A. For this purpose, the cover plate 18 includes a raised portion 16b for cooperating with the stop portion 18b. On the back side of the main body portion 16A, arc-shaped first and second lands r1 and r2 extending in the circumferential direction are formed in a state of point symmetry with respect to the rotation axis X.

  The shaft portion 16a protrudes outside through the shaft hole 18a of the cover plate 18, and an operation knob 19 composed of a disk-shaped flange portion 19a and a knob portion 19b is provided at the tip portion of the shaft portion 16a. A structure for fitting and fitting may be used. In this case, the movable valve body 16 can be rotated by turning the knob portion 19b with fingers (see FIG. 1 and the like). In FIG. 6 (a), the raised portion 16b is formed in a two-position switching type between an operating position and a return position, but by changing the shape, a three-position switching type in which the blocking position shown in FIG. 1 is added. You can also do it.

  As shown in FIGS. 2 to 6A, the valve passage block 17 has first to sixth supply / exhaust ports p1 to p6 formed on the valve body side surface 17a facing the valve body block 15, and the first bottom face 17b. And the second supply / discharge port k1, k2 wins, and the third supply / discharge port k3 is formed on the lateral surface 17c. The third and fourth supply / discharge ports p3 and p4 arranged on the left and right sides of the upper side are both connected to the third supply / discharge port k3, and the lower first supply / discharge port p1 is connected to the first supply / discharge port p1. In addition, the lower second supply / discharge port p2 is connected to the second supply / discharge port p2. Upper and lower middle fifth and sixth supply / exhaust ports p5, p6 pass through the valve passage block 17 and face the pump side surface 17d facing the pump block 14, and respectively to the discharge port 21 and the suction port 22 of the fuel pump 5B. Communication connection. The valve passage block 17 is formed with an upper base 17n having a nut portion and a side attachment portion 17h having a bolt hole so as to fix the pump 5 with switching means to the engine E. ing.

  That is, the supply / discharge ports k1 to k3 are connected to the first supply / discharge port k1 communicated with the fuel inlet 4a of the carburetor 3, the second supply / discharge port k2 communicated with the drain port 4b of the carburetor 3, and the fuel tank 1. The third supply / exhaust port k3 communicates, and the supply / discharge ports p1 to p6 communicate with the first supply / exhaust port p1 communicated with the first supply / exhaust port k1 and the second supply / exhaust port k2. A sixth supply / discharge port (suction port) connected to the second supply / discharge port p2, the third and fourth supply / discharge ports p3, p4 communicated with the third supply / discharge port k3, and the suction port 22 of the pump block 14 Example) p6 and a fifth supply / discharge port (an example of the discharge port) p5 communicated with the discharge port 21 of the pump block 14. Although illustration is omitted, a total of six holes corresponding to the first to sixth supply / discharge ports p1 to p6 are also formed in the gasket 20.

  As shown in FIGS. 2 to 6, the pump block 14 is configured by a block body equipped with a fuel pump 5 </ b> B, and a discharge port 21 of the fuel pump 5 </ b> B is provided on a valve passage side surface 14 a facing the valve passage block 17. And an inlet 22 are formed. Although not shown, the fuel pump 5B is configured as a negative pressure pump (feed pump) that is provided with a pressure hose 23 that transmits pulsation generated in the engine E and operates by the pulsation.

  By the way, as shown in FIG.1, FIG.5, FIG.6, the movable valve body 16 which is a part of path | route switching means 5A has an air release path for making the 1st piping h1 into an air release state only in a recirculation | reflux state. 40 is provided. That is, the air release path 40 has a diameter formed so as to penetrate the main body portion 16A of the movable valve body 16 so as to communicate with the first supply / discharge port p1 only in the reflux state shown in FIG. The external communication hole 40 is a very small hole. In this example, as shown in FIG. 6, the external communication hole 40 is formed through at an angular position close to the lower side of the first land r1. Next, the function of the pump 5 with switching means will be described.

  As shown in FIG. 1, the pump 5 with switching means includes an operation state obtained by rotating the operation knob 19 to the operation position “luck” and a reflux state obtained by rotating the operation knob 19 to the return position “return”. And a shut-off state obtained by rotating to the shut-off position “block” is configured to be freely selectable. It switches to the operating state during normal engine operation, and switches to the shut-off state during transportation such as loading on a truck. Further, when the engine is stopped for a long period of time due to the season off or the like, it is operated so as to be in a reflux state.

  As shown in FIG. 2, the operating state is obtained by rotating the operation knob 19 to the “luck” position. That is, in this operation state, the first supply / discharge port p1 and the fifth supply / discharge port p5 are communicated with each other by the first land r1, and the sixth supply / discharge port p6 and the fourth supply / discharge port p4 are connected to the second land. It will be communicated by r2. Therefore, by the operation of the fuel pump 5B, the fuel movement path is changed from the discharge port 1a of the fuel tank 1 to the third pipe h3, the third supply / discharge port k3, the fourth supply / discharge port p4, the second land r2, and the sixth. Supply / discharge port p6 → suction port 22 → fuel pump 5B → discharge port 21 → fifth supply / discharge port p5 → first land r1 → first supply / discharge port p1 → first supply / discharge port k1 → first pipe h1 → fuel inlet The gasoline in the fuel tank 1 is supplied to the float chamber 4 of the carburetor 3.

  Therefore, during normal engine operation, such as moving an agricultural machine in a field such as a farm, the pump 5 with switching means is operated to operate, and the gasoline in the fuel tank 1 is satisfactorily supplied to the carburetor 3 by the fuel pump 5B. It can be in a state.

  The reflux state is obtained by rotating the operation knob 19 to the “return” position as shown in FIG. That is, in this reflux state, the fifth supply / discharge port p5 and the third supply / discharge port p3 are communicated by the first land r1, and the sixth supply / discharge port p6 and the second supply / discharge port p2 are connected to the second land. The first supply / exhaust port p <b> 1 is communicated with the external communication hole 40 while being communicated by r <b> 2. That is, in this recirculation state, the path switching means 5A side end of the first pipe h1 is open to the atmosphere, and air can freely enter.

  Accordingly, when the fuel pump 5B is operated, the fuel movement path is as follows: drain port 4b → second pipe h2 → second supply / exhaust port k2 → second supply / exhaust port p2 → second land r2 → sixth supply / exhaust port p6. → intake port 22 → fuel pump 5B → discharge port 21 → fifth supply / discharge port p5 → first land r1 → third supply / discharge port p3 → third supply / discharge port k3 → third pipe h3 → discharge port 1a, float Residual gasoline remaining in the chamber 4 is reduced into the fuel tank 1. In addition, when fuel is present in the first pipe h1, the remaining fuel flows into the float chamber 4 by gravity or by the suction action of the fuel pump 5B. From there, the drain port 4b is passed through as described above. After that, it is returned to the fuel tank 1. As a result, all fuel in the fuel piping system is returned to the fuel tank 1. The external communication hole 40 is blocked at the side end of the valve passage block 17 at a switching position other than the recirculation state, and does not have an adverse effect.

  Therefore, when the predetermined operation is completed and the season of the agricultural machine is turned off, the operation knob 19 is turned “operating” in the state where the pump 5 with switching means is operated to operate and the engine is operating (rotating). "Rotate" from "Position" to "Return" position. Then, the gasoline stored in the float chamber 4 is forcibly returned to the fuel tank 1 by the fuel pump 5B and simultaneously supplied to the engine E that continues to rotate. Therefore, the residual fuel in the float 4 is rapidly discharged, The engine is stopped in a few seconds (3 to 5 seconds) in an extremely lean fuel state. When the engine stops, the fuel pump 5B also stops. However, even after the explosion in the combustion chamber of the engine stops, the engine rotates for a short time due to inertia, so the inertial rotation causes the fuel pump to operate and remains in the float chamber 4 A very small amount of fuel is also reduced into the fuel tank 1. That is, the engine E is stopped and the gasoline is not left in the float chamber 4 only by switching the pump with switching means 5 to the shut-off state.

  As a result, when the rotation of the engine E stops, the inside of the float chamber 4 and the supply path h1 are completely emptied, and the inside of the carburetor 3 (within the float chamber 4) and the supply due to long-term non-use. It is possible to avoid inconveniences (next-time engine start failure, start failure, hunting, etc.) due to deterioration (degeneration) of the fuel accumulated in the path h1.

  As shown in FIG. 4, the blocking state is obtained by rotating the operation knob 19 to the “blocking” position. That is, in this shut-off state, the first land r1 opens only to the first supply / discharge port p1, and the second land r2 opens only to the fourth supply / discharge port p4. All of the 6 supply / discharge ports p1 to p6 are closed, and a state where no fuel flow occurs is envisaged.

  For example, when an agricultural machine such as a management machine or a rice transplanter is loaded and moved on a truck bed, the farm machine loaded by traveling vibration or the like, that is, the carburetor 3 swings. When 19 is operated to the “luck” position, the gasoline in the float chamber 4 may ooze out or leak into the carburetor 3 other than the float chamber such as the intake manifold or the air cleaner side passage. For example, if gasoline leaks into the intake manifold, it is supplied to the engine, but the air-fuel mixture becomes thick, and there is a disadvantage in that starting failure (so-called “over-engine” situation) occurs at the next engine start. Further, if the air cleaner leaks into the air cleaner side passage, gasoline will permeate through the air cleaner element and the air-fuel mixture will become thicker at the next start, leading to a start failure.

  Therefore, when the agricultural machine is moved and transported while the engine is stopped, the operation knob 19 is moved to the “blocking” position so that the pump 5 with the switching means is switched off. Since both the inlet 4a and the drain port 4b are closed, gasoline leakage from the float chamber 4 to the inside of the carburetor 3 is surely prevented even if the agricultural machine that is the load is shaken by traveling vibration, rough road traveling, etc. The effect which eliminates the above-mentioned inconvenience is acquired.

  By the way, although illustration is omitted, as the ignition switch 8 having an ON position for starting and working the engine and an OFF position for stopping the engine is switched, the operation knob 19 is switched (switching means). An interlocking mechanism for rotating the attached pump 5 may be provided. That is, the interlocking mechanism turns the operation knob 19 to the “luck” position and turns the ignition to stop the engine as the ignition switch 8 is turned to the ON position to turn the engine E to obtain the operating state of the agricultural machine. As the switch 8 is operated to the OFF position, the operation knob 19 is rotated to the “blocking” position, and the ignition switch 8 is operated to the second OFF position (not shown) to stop the engine for a long time. Accordingly, the operation knob 19 functions to be rotated to the “return” position. That is, if the ignition switch 8 is operated, the pump 5 with switching means is automatically operated to a desired state, which is more convenient.

  For reference, an attachment structure to the engine E of the pump 5 with switching means that is a two-position switching type between an operation position and a return position and a switching operation structure will be schematically described. As shown in FIGS. 7 and 8, the movable valve body 16 is switched by an operation arm 30 attached to the shaft portion 16 a and an operation bar 31 pivotally connected to the distal end side of the operation arm 30. It is supposed to be a structure. That is, by pushing and pulling the operation bar 31 made of a wire with fingers, the operation arm 30 is swung to move the movable valve body 16 to move the pump 5 with switching means between the operation state and the reflux state. Alternatively, a switching operation can be performed.

  The pump 5 with switching means is fixedly mounted using a support plate 32 bolted to the upper part of the engine E, and the operation bar 31 is good due to a sheet metal bracket 34 bolted to the upper part of the air cleaner 33. It is guided so that it can be pushed and pulled. Specifically, the upper base 17n and the side mounting portion 17h of the valve passage block 17 are bolted to the distal end side of the bent support plate 32, and the distal bent portion 32a of the support plate 32 is operated by the operation. The arm 30 is configured so as to be externally fitted and supported on the rotating cylinder portion 30 a of the arm 30. The air cleaner 33 is attached to the engine E via the carburetor 3.

  As described above, in the fuel supply device A for an engine according to the present invention, the path switching means 5A is provided with the atmosphere open path 40 for opening the supply path h1 to the atmosphere only in the reflux state. It is possible to reduce the fuel existing in the supply path h1 that could not be removed in the past to the fuel tank 1, so that no residual fuel is produced in the recirculation state, and the engine starts well in the next season. The effect which can be performed can be acquired in a higher dimension.

System diagram showing schematic structure of engine fuel supply system Exploded perspective view of pump with switching means showing fuel flow in operating state Exploded perspective view of pump with switching means showing fuel flow in recirculation state Exploded perspective view of pump with switching means showing fuel flow in shut-off state Side view of a partially cutout showing the schematic structure of a pump with switching means (A) is a front view of a pump with switching means, (b) is a rear view of a movable valve body. Front view showing schematic mounting structure of pump with switching means Side view showing schematic mounting structure of pump with switching means

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel tank 2 Fuel supply / discharge route 3 Vaporizer 4 Float chamber 4a Fuel inlet 4b Drain port 5 Pump with switching means 5A Path switching means 5B Fuel pump 14 Pump block 15 Valve body block 16 Movable valve body 17 Valve passage block 40 Atmospheric release Road k1 First supply / discharge port k2 Second supply / discharge port k3 Third supply / discharge port p1 First supply / discharge port p2 Second supply / discharge port p3 Third supply / discharge port p4 Fourth supply / discharge port p5 Discharge port p6 Suction port A Fuel supply device

Claims (3)

A fuel pump (5B) and a path switching means (5A) are connected to a fuel supply / discharge path (2) connecting the engine carburetor (3) having the float chamber (4) and the fuel tank (1). The operation state of supplying the fuel from the fuel tank (1) to the carburetor (3) by the operation of the fuel pump (5B) by the switching operation of the path switching means (5A), and the fuel pump (5B The fuel supply device for the engine is configured to be switchable between a return state in which the residual fuel in the float chamber (4) is returned to the fuel tank (1) by the operation of
In the operating state, the fuel discharged from the fuel pump (5B) passes through the path switching means (5A) and the supply path (h1) connecting this to the vaporizer (3), and the float chamber (4). In the recirculation state, the residual fuel in the float chamber (4) is passed through the path switching means (5A) and the discharge path (h2) connecting this to the carburetor (3). While being configured to be sucked into the fuel pump (5B), the path switching means (5A) has an atmosphere open path (40) for opening the supply path (h1) to the atmosphere open only in the reflux state. A fuel supply device for an engine provided.   The path switching means (5A) includes a valve body block (15) having a movable valve body (16) which can be switched and moved, a first supply / discharge port (p1) communicating with the supply path (h1), A second supply / discharge port (p2) communicating with the discharge path (h2) and a plurality of supply / discharge ports (p3) to (p6) corresponding to the fuel pump (5B) and the fuel tank (1) are formed. And the air release path (40) is connected to the first supply / exhaust port (p1) only when the movable valve body (16) is switched to the reflux state. The fuel supply device for an engine according to claim 1, wherein the fuel supply device is an external communication hole formed at a predetermined position of the movable valve body (16) so as to open. The plurality of supply / discharge ports (p3) to (p6) are connected to the third and fourth supply / discharge ports (p3) and (p4) communicated with the fuel tank (1) and the discharge of the fuel pump (5B). A discharge port (p5) communicating with the outlet (21) and a suction port (p6) communicating with the suction port (22) of the fuel pump (5B);
When the movable valve body (16) is switched to the operating position, the fourth supply / discharge port (p4) and the suction port (p6) communicate with each other, and the first supply / discharge port (p1) and the discharge port (P5) is communicated with the operating state, and when the movable valve body (16) is switched to the return position, the suction port (p6) and the second supply / exhaust port (p2) are communicated. The engine fuel supply device according to claim 2, wherein the recirculation state in which the discharge port (p5) and the third supply / discharge port (p3) communicate with each other is obtained.

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