JPH0545815Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fuel tank for an engine, such as a portable engine, which can open and close both the fuel passage and the air vent atmospheric passage of the fuel tank.

[Problems to be solved by conventional technology and ideas] Generally, in portable engines, etc., a fuel passage is inserted between the fuel tank and the carburetor, etc.
This fuel passage can be opened and closed as required.

Further, the fuel tank is provided with an air vent to prevent fuel leakage due to expansion of gas in the fuel tank and to eliminate insufficient fuel supply to the engine due to low pressure in the fuel tank.

By the way, if the atmospheric passage of the air vent is always in communication, if the engine is left unused for a long time, vaporized gas will leak from the air vent and cause a gasoline odor. When transporting the fuel, fuel may be discharged from the air vent due to vibrations or other effects.

In order to prevent this, for example, in Japanese Utility Model Application Publication No. 55-176476, a gas valve that is linked to the opening and closing of the fuel gas valve is interposed in the atmospheric passage of the air vent, and when the fuel gas valve is opened when the engine is stopped, the air passage A technique is disclosed in which the valves are closed at the same time.

However, according to this prior art, one spool is provided with passages that communicate with the fuel passage and the atmosphere passage, respectively, and by rotating the spool by a predetermined angle, the passages communicate with the fuel passage and the atmosphere passage. Because it is designed to be selectively opened and closed,
At the time of switching, the entire spool is slid, which creates a large sliding resistance and is difficult to operate.

Furthermore, when the fuel tank is closed, the atmospheric passage of the air vent is also completely opened, so after running the engine for a long time when the outside temperature is low, especially in cold regions or during winter, stop the engine and close the tank. The fuel tank is warmed by radiant heat from the engine, and there is a large temperature difference between it and the outside air, so as the fuel tank is cooled by the outside air, the air in the upper space inside the fuel tank contracts. , there is a problem that the air pressure inside the fuel tank decreases and the fuel tank deforms.

[Purpose of the invention] This invention was made in view of the above circumstances.
To provide a fuel tank for an engine that has low sliding resistance of a spool that switches between opening and closing a fuel passage and an atmospheric passage, has good operability, and prevents deformation of the fuel tank.

[Means for Solving the Problems] The fuel tank for an engine according to the present invention has a fuel chamber and an air vent chamber formed in the fuel tank body, a fuel control valve interposed in a discharge passage communicating with the fuel chamber, Further, an air control valve is interposed in an inflow passage communicating with the air vent chamber, an operating member for opening and closing both control valves is provided on a spool communicating with both the chambers, and the volume of the fuel chamber is adjusted to the air vent chamber. It is formed to be larger than the volume of the chamber, and both chambers are defined by sealing members provided on the spool.

[Function] In the above configuration, in a normal state and during engine operation, the spool is rotated by a predetermined angle, and the operating member provided on the spool operates to control the fuel control valve interposed in the protruding passage communicating with the fuel chamber; The air control valves interposed in the inflow passages communicating with the air vent chamber are opened. Then, the fuel stored in the fuel tank, etc. is supplied to the engine intake system through the fuel chamber formed in the fuel tank body, and at the same time, the atmosphere is discharged from the air vent chamber, which is opened, to the upper part of the fuel tank, etc. There will be an influx.

Since the fuel control valve is provided on the discharge side of the fuel chamber, the fuel chamber is always filled with fuel even when the fuel control valve is closed. Therefore, when the control valve is opened, fuel is discharged into the intake air. immediately supplied to the system.

Further, since the volume of the fuel chamber is larger than the volume of the air vent chamber, air bubbles in the fuel flow easily in the fuel chamber, thereby preventing vapor lock from occurring.

On the other hand, if the engine is stopped for a long time,
The spool is rotated, and the two control valves are closed by each rotating member provided on the spool. Then, the supply of fuel to the intake system is stopped, and at the same time, the inflow of the atmosphere into the upper part of the fuel tank is blocked, and the inside of the fuel tank is sealed. Since this air control valve is interposed on the inflow side of the air vent chamber, water droplets and the like will not remain in the air vent chamber when the valve is closed.

[Embodiments of the invention] Hereinafter, embodiments of the invention will be described with reference to the drawings.

The drawings relate to one embodiment of the present invention, and FIG. 1 is a plan view of the fuel pot, FIG. 2 is a front view of the fuel pot,
3 is a right side view of FIG. 1, FIG. 4 is a sectional view of FIG. 1, FIG. 5 is a sectional view of FIG. 1, FIG. 6 is a sectional view of FIG. The figure is a - sectional view of Fig. 2, Fig. 8 is a - sectional view of Fig. 4,
FIG. 9 is a piping diagram of the fuel tank connected to the fuel tank.

In these figures, reference numeral 1 denotes a fuel pot main body, and a recess 1a of a predetermined depth is bored in this fuel pot main body 1. A spool 2 is inserted into this recess 1a. An operating lever 3 is integrally formed at the upper end of this spool 2, and an annular groove 2a is formed at the upper and lower parts of this spool 2.
The recess 1a of the fuel tank main body 1 is defined into a fuel chamber 5 and an air vent chamber 6 by an O-ring 4, which is an example of a sealing member, fitted to the annular groove 2a.

In addition, the fuel chamber 5 is attached to the fuel tank body 1.
and an inflow passage 5a communicating with the air vent chamber 6, respectively.
6a, and discharge passages 5b, 6b are formed.

As shown in FIG. 5, a joint 10 connected to the bottom of the fuel tank 8 via a fuel passage 9 is screwed into an inlet port 5c of an inflow passage 5a communicating with the fuel chamber 5, and an O-ring 11 It is sealed by. Further, a fuel filter 12 is attached to this joint 10. Note that reference numeral 13 is a ball that closes the hole drilled during post-processing.

On the other hand, a joint 16 is press-fitted into the outlet port 5d of the discharge passage 5b, which communicates with the fuel chamber 5, and which communicates with a float chamber (not shown) of the intake system via the fuel passage 15.

Further, a piston valve 14, which is an example of a control valve, is interposed in the discharge passage 5b. The outer circumference of the piston 14a of this piston valve 14 is
Piston guide 1 protruding into the discharge passage 5b
8 and is slidably supported. Further, a stepped portion 14b is formed on the upper surface of the piston 14a, and an O-ring 17 that is tightly fitted to the end of the discharge passage 5b is attached to this stepped portion 14b. Furthermore, a rod 14c is provided protruding from the upper end of this stepped portion 14b,
The tip of this rod 14c projects into the fuel chamber 5.

On the other hand, there is a gap between the skirt portion of the piston 14a and a plug 21 screwed onto the rear end of the discharge passage 5b via an O-ring 20.
a compression spring 22 that presses the O-ring 17 screwed onto the stepped portion 14b of the discharge passage 5b;
is interposed.

Further, a joint 23 is tightly screwed to the inflow end of the inflow passage 6a communicating with the air vent chamber 6 via an O-ring 24.
3 is formed with an inlet port 6c that communicates with the upper part of the fuel tank 8 via an air passage 25.

Further, a piston valve 26, which is an example of a control valve, is interposed in the inflow passage 6a communicating with the air vent chamber 6. This piston valve 26
The outer periphery of the piston 26a is slidably supported on the wall surface of the inflow passage 6a. Further, a stepped portion 26b is formed on the upper surface of the piston 26a, and an O-ring 27 is attached to the stepped portion 26b, which is brought into close contact with the end of the inflow passage 6a. Furthermore, a rod 26c is provided protruding from the upper end of this stepped portion 26b,
The tip of this rod 26c projects into the air vent chamber 6.

Further, between the skirt portion of the piston 26a and the joint 23, the piston 26a
a compression spring 28 that presses the O-ring 27 fitted on the stepped portion 26b toward the end face of the inflow passage 6a;
is interposed. Furthermore, the air vent chamber 6
Outlet port 6 of discharge passage 6b communicating with
d is press-fitted with a joint 30 that communicates with the atmosphere via an atmospheric passage 29.

On the other hand, cams 31 and 32, which are examples of operating members, are integrally formed in a portion of the spool 2 facing the fuel chamber 5 and the air vent chamber 6. The cams 31, 32 have the same cam profile, and their cam lobes 31a, 32a are similar to the pistons 14a, 26a of the piston valves 14, 26, which protrude into the fuel chamber 5 and air vent chamber 6, respectively.
The tips of the rods 14c and 26c protruding from the rods are simultaneously pressed into engagement or disengaged.

Further, a plate 33 that is fastened to the engine body or equipment frame (not shown) is fixed on the upper surface of the fuel tank body 1, and this plate 33 prevents the spool 2 from slipping out. A stopper 33a is formed to regulate the opening/closing angle of 2.

Next, the operation of the fuel pot with the above configuration will be explained.

When starting the engine after it has been stopped for a long time, or when starting the engine after it has been loaded and transported in a car or the like and then set in a predetermined position, first, it is inserted into the recess 1a of the fuel pot main body 1.
The inside of this recess 1a is connected to the fuel chamber 5 and air vent chamber 6.
The operating lever 3 integrally formed with the spool 2 partitioned by the ring 4 is rotated clockwise from the state shown in FIG.

Then, a pair of cams 31 and 32 facing the fuel chamber 5 and the air vent chamber 6 and integrally formed with the spool 2 rotate in the same direction.

The cam 31 facing the fuel chamber 5
This presses a rod 14c that projects from a piston 14a of a piston valve 14 that is interposed in a discharge passage 5b that communicates with the fuel chamber 5. Then, the piston 14a resists the biasing force of the compression spring 22 and retreats while being supported by the piston guide 18 fitted in the discharge passage 5b.

On the other hand, the cam 3 facing the air vent chamber 6
2 is an inflow passage 6 communicating with this air vent chamber 6.
The piston 2 of the piston valve 26 interposed in a
Press the rod 26c protruding from 6a. Then, the piston 26a resists the biasing force of the compression spring 28 and is supported by the inner wall of the inflow passage 6a to retreat.

When the spool 2 is latched onto a stopper 33a formed on a plate 33 that is fixedly abutted to the fuel tank body 1, and its rotation is restricted, the cam lobes 31a of both the cams 31, 32,
32a presses the pistons 14a, 26a of the piston valves 14, 26 to the stroke end, and the discharge passage 5b communicating with the fuel chamber 5 and the inflow passage 6a communicating with the air vent chamber 6 are fully opened at the same time.

As a result, the fuel stored in the fuel tank 8 passes through the fuel passage 9 to the joint 10 screwed into the inlet port 5c of the fuel tank main body 1.
After being filtered by a fuel filter 12 attached to this joint 10, the inflow passage 5a, fuel chamber 5, discharge passage 5b, and fuel passage 1 are
5, and is supplied to a float chamber of a carburetor provided in the intake system of the engine (not shown).

At the same time, the upper part of the fuel tank 8 is connected to the air passage 25 and the inflow passage 6 of the fuel tank main body 1.
a, air vent chamber 6, discharge passage 6b, atmospheric passage 2
The fuel tank 8 is communicated with the atmosphere through the fuel tank 9, thereby preventing a pressure drop in the fuel tank 8 due to the fuel supply, and at the same time, vaporized gas generated in the fuel tank 8 is released to the atmosphere.

Also, if the engine is left stopped for a long time,
Alternatively, when the spool 2 is mounted on a car or the like and moved, the spool 2 is moved to the state shown in FIG.
The spool 2 is rotated counterclockwise in the figure from the fully open position, and the spool 2 is engaged with a stopper 33a formed on the plate 33.

Meanwhile, the pistons 14a and 26a of the piston valves 14 and 26, which are integrally formed with the spool 2 and are in sliding contact with the cam lobes 31a and 32a of the cams 31 and 32 facing the fuel chamber 5 and the air vent chamber 6, are Protruding rod 14c, 2
6c is the cam 3 that rotates as the spool 2 rotates.
The cam surfaces 1 and 32 are slid relative to each other. The tips of the rods 14c and 26c are connected to the cams 31 and 3.
As the pistons 14a, 26a move away from the cam lobes 31a, 32a of the compression springs 2,
It is gradually projected by receiving the urging force of 2 and 28.

Then, almost at the same time as the piston 14a closes the fuel chamber 5, the O-ring 27 attached to the step 26b formed on the upper surface of the piston 26a is brought into close contact with the end surface of the inflow passage 6a. The passage 6a and the air vent chamber 6 are shut off.

As a result, the supply of the fuel stored in the fuel tank 8 to the float chamber (not shown) of the carburetor of the intake system is stopped, and the fuel tank 8 is hermetically sealed. Liquid leakage and vaporized gas leakage are prevented.

By the way, the cam 3 formed on the spool 2
1 and 32 and the biasing forces of the compression springs 22 and 28, the pistons 14a and 26a of the piston valves 14 and 26 are opened and closed.
Low sliding resistance and good operability. Further, since both the fuel chamber 5 and the air vent chamber 6 are opened and closed by rotating one spool 2, the operation is easy.

In this embodiment, the piston valve 26 is disposed in the inflow passage 6a communicating with the air vent passage 6. Therefore, when the engine is operated for a long time at low outside air temperatures such as in cold regions or in winter, and then the engine is stopped and the fuel passage and the air passage are closed, the fuel tank is cooled by outside air from a state in which the fuel tank is warmed by radiant heat from the engine, and the air in the upper space of the fuel tank contracts, cooling the fuel tank and causing a drop in the air pressure in the fuel tank. Then, the piston 26a moves backward against the biasing force of the compression spring 28, opening the piston valve 26 and closing the inflow passage 6a.
When the fuel tank is in communication with the atmospheric pressure, the atmospheric pressure is introduced into the fuel tank, and the air pressure in the fuel tank approaches the atmospheric pressure.
As a result, deformation of the fuel tank due to a drop in air pressure within the fuel tank is prevented.

Furthermore, when the pressure inside the fuel tank approaches atmospheric pressure, the piston 26a of the piston valve 26 protrudes due to the biasing force of the compression spring 28, thereby blocking the inflow passage 6a and the air vent chamber 6 again.

Note that the fuel tank according to the present invention is not limited to the above-mentioned embodiment. For example, the position of the cam lobe 32a of the cam 32 in the air vent chamber 6 may be shifted relative to the cam lobe 31a, and the operating lever 3 may be moved.
In the above operation, the air vent may be opened first to bring the internal pressure of the fuel tank 8 to atmospheric pressure, and then the fuel passage may be opened.

Furthermore, for example, the control valve is not limited to a piston valve, nor is the operating member limited to a cam.

Furthermore, the control valve is located on the opposite side of the embodiment, that is, an inflow passage 5a communicating with the fuel chamber 5.
The discharge passage 6b communicating with the air vent chamber 6 may be interposed therebetween.

[Effects of the invention] As explained above, according to the invention, the inflow passage and the discharge passage communicate with the fuel chamber and the air vent chamber formed in the fuel tank body, respectively, and one of the inflow passage and each discharge passage communicates with the fuel chamber and the air vent chamber formed in the fuel tank body. A control valve is installed in each of the control valves, and an operating member that opens and closes both control valves is provided on a spool inserted into both chambers, and by rotating one spool, the fuel chamber and air vent chamber are opened and closed. Since both are opened and closed at the same time, operation becomes easy.

In addition, since the operating member provided on the spool opens and closes the control valves installed in one of the inflow passages and the discharge passages, which communicate with the two passages, the conventional spool slides entirely. Compared to this, there is less sliding resistance and the operability is greatly improved. Furthermore, since there is less sliding resistance, wear of each component is reduced, resulting in a longer product life.

In addition, since the fuel control valve is installed on the discharge side of the fuel chamber, the fuel chamber is always filled with fuel even when the fuel control valve is closed. Therefore, the fuel control valve can be opened after a long stop. Even when the valve is closed, fuel is immediately supplied to the intake system, making it possible to obtain good starting performance.

Furthermore, since the volume of the fuel chamber is made larger than the volume of the air vent chamber, the flow of fuel is improved and the occurrence of vapor lock in the fuel chamber can be prevented.

In addition, an air control valve is installed on the inflow side of the air vent chamber, so by closing this air control valve, water droplets can be prevented from entering the air vent chamber. Water droplets do not accumulate in the air vent chamber even when the air vent is open, making it easy to handle.

On the other hand, since both chambers are formed by sealing members provided on the spool, there is no need to provide sealing properties to the spool itself, the spool can rotate smoothly, and manufacturing and assembly are facilitated.

[Brief explanation of the drawing]

The drawings relate to one embodiment of the present invention, and FIG. 1 is a plan view of the fuel pot, FIG. 2 is a front view of the fuel pot,
3 is a right side view of FIG. 1, FIG. 4 is a sectional view of FIG. 1, FIG. 5 is a sectional view of FIG. 1, FIG. 6 is a sectional view of FIG. The figure is a - sectional view of Fig. 2, Fig. 8 is a - sectional view of Fig. 4,
FIG. 9 is a piping diagram of the fuel tank connected to the fuel tank. 1...Fuel pot body, 2...Spool, 4...
... Seal member (O ring), 5 ... Fuel chamber, 5a,
6a...Inflow passage, 5b, 6b...Discharge passage, 6
... Air vent chamber, 14 ... Fuel control valve (piston valve), 26 ... Air control valve (piston valve), 31, 32 ... Operating member (cam).

Claims (1)

[Scope of Claim for Utility Model Registration] A fuel chamber and an air vent chamber are formed in the fuel chamber, a fuel control valve is interposed in the discharge passage communicating with the fuel chamber, and a fuel control valve is interposed in the discharge passage communicating with the air vent chamber. An air control valve is interposed therein, and an operating member for opening and closing the two control valves is provided on a spool communicating with the two chambers, and the volume of the fuel chamber is formed to be larger than the volume of the air vent chamber; A fuel tank for an engine, characterized in that both of the chambers are defined by sealing members provided on the spool.