JP2896848B2 - Gasoline engine fuel supply system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply system for a gasoline engine, and more particularly to a system for easily draining a float chamber of a vaporizer when the engine is stored for a long time.

[0002]

The basic structure of a fuel supply system of a gasoline engine to which the present invention BACKGROUND OF THE INVENTION As shown in FIG. 1 or FIG. 3, a fuel tank 1 of a gasoline engine E of the vaporizer 4 through the feed pump 3 This is a type in which a fuel supply passage 6 communicates with an inlet 5 a of the float chamber 5, and a drain port 7 is provided at a bottom 5 b of the float chamber 5.

[0003]

2. Description of the Related Art As a prior art of this type, as shown in FIG. 3 , a fuel filter 2 and a feed pump 3 are sequentially provided in a fuel supply passage 6 of a gasoline engine E at a lower flow side, and a fuel tank 1 in a fuel tank 1 is provided. The fuel is filtered by the fuel filter 2,
The feed pump 3 is configured to feed pressure to the vaporizer 4,
Generally, a stopper 50 is detachably screwed to the drain port 7 of the float chamber 5.

[0004] Usually, when the engine is stopped by the turning-off operation, fuel remains in the float chamber 5. Therefore, when the gasoline engine E is stored for a long period of time, the stop plug 50 is inserted through the drain port 7 of the float chamber 5. , And the fuel remaining in the float chamber 5 is drained from the drain port 7 to the outside of the vaporizer 4 to perform a drain operation.

[0005]

In the above-mentioned prior art, when the drain operation is performed, an operator manually pulls out and removes the stopper 50 to remove the fuel, so that the hand and the surroundings of the engine are contaminated with the fuel and the waste oil is removed. Processing is complicated. In addition, when the engine is housed in a hood or the like of a work machine, the operation of removing and removing the stopper 50 or the stopper 50 is performed in relation to peripheral devices.
The contact itself may be difficult, and the drain operation is not easy. An object of the present invention is to simplify drain operation of a float chamber of a vaporizer when a gasoline engine is stored for a long time.

[0006]

Means for achieving the above object will be described below with reference to FIGS. 1 and 2 showing an embodiment. That is, the present invention provides a fuel supply device for a gasoline engine having the basic structure described above, wherein the drain port 7 of the float chamber 5 communicates with the fuel tank 1 by the drain flow path 12, and the intersection of the fuel supply path 6 and the drain flow path 12 is provided. Channel switching device 8
And the first flow path 10 and the second flow path 1
1, the first flow path 10 of the flow path switching device 8 is communicated with the fuel supply path 6, the second flow path 11 is communicated with the drain flow path 12, and the flow path switching tool 8 is connected to the fuel supply position A and the drain. When the fuel supply position A is switched to the fuel supply position A, the first flow path 1 is switched.
0 is opened, the second flow path 11 is closed, and fuel is
Is supplied to the carburetor 4 from the fuel supply path 6 through the first flow path 10 of the flow path switching device 8 and the feed pump 3, and when the flow path switching device 8 is switched to the drain position B, the first flow path 10 Is closed, the second flow path 11 is opened, and the fuel in the float chamber 5 flows from the drain port 7 to the fuel tank 1 via the feed pump 3 and the second flow path 11 of the flow path switching tool 8 via the drain flow path 12. It is characterized by being returned.

[0007]

According to the present invention, since the flow switching device 8 is provided at the intersection of the fuel supply passage 6 and the drain flow channel 12, when the flow switching device 8 is switched to the fuel supply position A during the operation of the engine, the flow is switched. Since the first flow path 10 of the path switching tool 8 is opened and the second flow path 12 is closed, the fuel is supplied from the fuel tank 1 through the first flow path 10 of the flow path switching tool 8 by the pumping force of the feed pump 3. 4 is supplied smoothly.

On the other hand, when the engine E is stored for a long period of time, when the flow switching device 8 is switched from the fuel supply position A to the drain position B, the first flow path 10 of the flow switching device 8 is closed, and the second flow Since the passage 12 is opened, the residual fuel in the float chamber 5 is supplied from the drain port 7 through the second flow path 11 of the flow path switching tool 8 by the feed force of the feed pump 3 in the same manner as in the case of the fuel supply. The liquid is smoothly returned to the tank 1 through the drain passage 12. Therefore, when the drain operation is performed, the fuel only flows through the drain passage 12 and is collected in the fuel tank 1, and does not leak to the outside.

[0009]

According to the present invention, the residual fuel in the float chamber can be returned to the fuel tank through the drain flow path without leaking to the fuel tank simply by switching the flow path switching tool to the drain position. When the gas is stored for a long period of time, drain operation of the float chamber of the vaporizer becomes extremely simple, and the hands of workers and the surroundings of the engine are not stained. Further, even when the engine is housed in the hood of the work machine, the difficulty of drain operation can be solved because only the flow path switching tool is operated. In addition, since the feed pump for supplying fuel can be used for drain operation, the drain mechanism can be simplified.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are schematic system diagram of a fuel supply system of a gasoline engine shown, each an embodiment of the present invention, FIG. 1 at the time of fuel supply, 2 is an explanatory diagram during the drain operation.

As shown in FIGS. 1 and 2, the bottom surface 1a of the fuel tank 1 of the gasoline engine E communicates with the inlet 5a of the float chamber 5 of the carburetor 4 through the fuel supply passage 6 to accommodate the needle valve. The fuel supply path 6 is provided with a fuel filter 2, a feed pump 3 composed of a diaphragm pump, and a flow path switching device 8, and the fuel in the fuel tank 1 is filtered by the fuel filter 2. The float chamber 5 is configured to be able to be pressure-fed. A drain port 7 is opened at the bottom 5b of the float chamber 5, and the drain port 7 communicates with the upper portion 1b of the fuel tank 1 via a drain flow path 12, and at the intersection of the fuel supply path 6 and the drain flow path 12, The flow path switching device 8 and the feed pump 3 are provided.

As shown in FIGS. 1 and 2, the channel switching member 8 is formed by rotatably fitting an inner plug 15 in a cylindrical body 14, and is forked at equal intervals in a circumferential direction of the cylindrical body 15. Guide channels 16a, b, c and two guide channels 17a, b, c are provided, and two sets of bifurcated middle channels 18, 19 are provided at intervals of approximately 120 degrees in the circumferential direction of the inner plug 15. Provided, each middle channel 18 (19) has three channels a, b,
The first flow path 10 and the second flow path 11 are configured by combining these different flow paths so as to simultaneously communicate with two different sets of flow paths of c. That is, the first flow path 10 is formed by the guide flow path 16a → the middle flow path 18 → the guide flow path 16c and the guide flow path 17c → the middle flow path 19 → the guide flow path 17a of the flow path switching tool 8. Guide channel 1
6b → middle channel 18 → guide channel 16c and guide channel 17
The second flow path 11 is formed by c → the middle flow path 19 → the guide flow path 17b.

As shown in FIGS. 1 and 2, the fuel filter 2 communicates with a guide passage 16a of a passage switching device 8,
The guide flow path 16c is connected to the suction port 3a of the feed pump 3, and the discharge port 3b of the feed pump 3 is connected to the flow path switching member 8.
The first flow path 10 of the flow path switching device 8 is configured to be able to communicate with the fuel supply path 6 by connecting the guide flow path 17c to the inlet flow path 5a of the float chamber 5. Further, the drain port 7 of the vaporizer 4 communicates with the guide passage 16b of the passage switching device 8, and the guide passage 17b is
And the second flow path 1 of the flow path switching device 8
1 is configured to be able to communicate with the drain channel 12.

As shown in FIGS. 1 and 2, in the flow path switching device 8, the guide flow path 16 (17) and the middle flow path 18 (19)
Flow path 10 and second flow path 1
1 can be selected, so that the operation unit 21 of the flow path switching tool 8 can be selected.
Accordingly, the inner plug 15 can be switched between the fuel supply position A and the drain position B by rotating the inner plug 15 relative to the cylindrical main body 14. When the flow path switching member 8 is switched to the fuel supply position A, the first flow path 10 is opened, the second flow path 11 is closed, and when the flow path switching tool 8 is switched to the drain position B, the first flow path 10 is closed and the second flow path 11 is opened.

Therefore, the function of the fuel supply device of the present embodiment will be described. (1) As shown in FIG. 1, during operation of the gasoline engine, the flow switching device 8 is switched to the fuel supply position A.
In this case, since the first flow path 10 of the flow path switching device 8 is opened and the second flow path 11 is closed, the fuel in the fuel tank 1 is filtered by the fuel filter 2 by the pumping force of the feed pump 3, and Guide passage 16a of switching tool 8 → middle passage 18
→ Guide passage 16c → Feed pump 3 → Guide passage 17c of passage switching device 8 → Middle passage 19 → Smooth from guide passage 17a (that is, first passage 10) to carburetor 4 through fuel supply passage 6. Supplied to

(2) As shown in FIG. 2, when the gasoline engine E is stored for a long period of time, instead of turning on the engine stop switch, the flow path switching device 8 is switched from the fuel supply position A to the drain position B. I do. Since the first channel 10 of the channel switching device 8 is closed and the second channel 11 is opened,
As in the case of fuel supply, residual fuel in the float chamber 5 is supplied from the drain port 7 to the guide flow path 16b of the flow path switching member 8 → the middle flow path 18 → the guide flow path 16c → feeding by the pumping force of the feed pump 3. Pump 3 → guide flow path 17 c of flow path switching device 8 → middle flow path 19 → guide flow path 17 b (that is, second flow path 11), smoothly returns to fuel tank 1 through drain flow path 12.

Therefore, when the gasoline engine is stored for a long period of time, it is possible to return the fuel remaining in the float chamber 5 to the fuel tank 1 without leaking the fuel simply by switching the flow path switching member 8 to the drain position B. As a result, the drain operation becomes extremely simple, and the operator is not stained. Further, since the feed pump 3 for supplying fuel can be used for this drain operation, the drain mechanism can be simplified.
When the operation of the gasoline engine E is simply stopped without storing the gasoline engine E for a long period of time, the engine is stopped by the engine stop switch while the flow path switching member 8 is kept at the fuel supply position A.

[Brief description of the drawings]

FIG. 1 is a schematic system diagram of a fuel supply device for a gasoline engine, showing an embodiment of the present invention , and is an explanatory diagram at the time of fuel supply.

FIG. 2 is an explanatory diagram at the time of drain operation of the fuel supply device.

FIG. 3 is a schematic system diagram of a fuel supply device showing a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fuel tank, 1a ... Bottom part of fuel tank , 2 ... Fuel filter, 3 ... Feed pump, 4 ... Vaporizer, 5 ... Float chamber, 5a ... Float chamber inlet, 5b ... Bottom part of float chamber, 6 ... Fuel supply Path: 7 Drain port, 8: Flow path switching tool, 10: First flow path of flow path switching tool, 11: Second flow path of flow path switching tool, 12: Drain flow path, A: Fuel supply position, B ... Drain position, E ... Gasoline engine.

Claims (1)

(57) [Claims] 1. A fuel tank (1) for a gasoline engine (E).
Through the feed pump (3) and the float chamber of the vaporizer (4)
(5) communicating with the fuel supply passage (6) to the inlet (5a) of a fuel supply system of a gasoline engine provided with a bottom portion (5 b) to the drain port (7) of the float chamber (5), a float chamber The drain port (7) of (5) communicates with the fuel tank (1) by a drain flow path (12), and a flow path switching device (8) is provided at the intersection of the fuel supply path (6) and the drain flow path (12). ), A first flow path (10) and a second flow path (11) are provided in the flow path switching tool (8), and the first flow path (10) of the flow path switching tool (8) is connected to the fuel supply path (6).
And the second flow path (11) is connected to the drain flow path (12), and the flow path switching tool (8) can be switched between the fuel supply position (A) and the drain position (B). Then, when the flow path switching device (8) is switched to the fuel supply position (A), the first flow path (10) opens, the second flow path (11) closes, and fuel flows from the fuel tank (1). The fuel is supplied to the carburetor (4) by the fuel supply path (6) through the first flow path (10) of the path switching device (8) and the feed pump (3), and the flow path switching device (8) is moved to the drain position. When the operation is switched to (B), the first flow path (10) is closed, the second flow path (11) is opened, and the fuel in the float chamber (5) flows from the drain port (7) to the feed pump (3) and the flow path. Second flow path (11) of road switching device (8)
A fuel supply device for a gasoline engine, wherein the fuel supply device is returned to the fuel tank (1) by a drain flow path (12) through the drain passage (12).