JPH053732Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a fuel vapor evaporation prevention device, and more particularly to a fuel vapor evaporation prevention device that effectively adsorbs a large amount of fuel vapor generated in a fuel tank.

[Conventional technology]

A fuel mechanism is generally equipped with a canister type device in order to prevent air pollution caused by the release of fuel vapor generated in a fuel tank or the like when the engine is stopped. In this device, fuel vapor generated in a fuel tank or the like when an internal combustion engine is stopped is temporarily adsorbed and held by an adsorbent such as activated carbon in a canister, thereby preventing it from being released into the atmosphere. In addition, the canister is equipped with a passage that communicates with the intake passage, which is the intake system, and an air hole that faces the atmosphere.During engine operation, atmospheric air flows in through the air hole and is adsorbed due to the pressure difference with the intake passage. The fuel thus released is separated and introduced into the intake passage through the passage to be combusted.

[Problem that the invention attempts to solve]

By the way, in conventional fuel vapor evaporation prevention devices, fuel vapor generated in the carburetor and intake pipe is collected in the air cleaner when the engine is stopped, and when the pressure in the air cleaner rises to a predetermined pressure, the fuel vapor in the air cleaner is collected. There is a method in which the canister is temporarily adsorbed and held (Japanese Patent Application Laid-open No. 79658/1983).
In this device, fuel vapor generated in the fuel tank is temporarily adsorbed and held in a canister having a constant adsorption capacity, as in the past.

As a result, in a device that temporarily adsorbs and holds fuel vapor generated in a fuel tank on a canister, for example, a large amount of fuel vapor that is generated when fuel is injected into a fuel tank can be effectively adsorbed and held on the canister. In addition, there is a risk that fuel vapor may be released into the atmosphere, and the canister must be enlarged in order to increase the adsorption capacity, which is economically disadvantageous.

[Effect of idea]

Therefore, in order to eliminate the above-mentioned inconvenience, the purpose of this invention is to surround the outside of the fuel tank formed by the inner wall with the outer wall to form a space around the entire outer circumference of the fuel tank, and to use the space to supply fuel into the fuel tank. A filter is provided extending to the outer peripheral end of the fuel injection port to be injected, and a filter is provided at the outer peripheral end of the fuel injection port.
By filling the space with an adsorbent to adsorb fuel vapor from the fuel tank and forming an adsorption section that is exposed to the atmosphere through a filter, we can effectively adsorb a large amount of fuel vapor generated in the fuel tank. A fuel vapor evaporation prevention device that is economically advantageous because there is no need to increase the size of the canister, and also allows the adsorption part to function as a buffer material and prevents fuel from flowing out from the fuel tank. The aim is to realize this.

[Means for solving problems]

In order to achieve this objective, this invention surrounds the outside of the fuel tank, which is composed of an inner wall, with an outer wall to form a space around the entire outer circumference of the fuel tank, and uses this space to inject fuel into the fuel tank. A filter is provided at the outer peripheral end of the fuel inlet, and the space is filled with an adsorbent to adsorb fuel vapor from the fuel tank, and is opened to the atmosphere by the filter. It is characterized in that it has a suction part formed therein.

[Effect]

With the above configuration, a large amount of fuel vapor generated when fuel is injected into the fuel tank, for example, can be temporarily adsorbed and held by the adsorption part formed around the entire outer circumference of the fuel tank and up to the outer circumferential end of the fuel injection port. This makes it possible to effectively adsorb fuel vapor, and also allows the adsorption part to function as a buffer material, thereby preventing fuel from flowing out from the fuel tank.

〔Example〕

Embodiments of this invention will be described in detail below based on the drawings.

1 to 3 show an embodiment of this invention. In these figures, reference numeral 2 denotes a fuel tank. This fuel tank 2 has a fuel chamber 4 formed therein by an upper inner wall 2a and a lower wall 2b, and the outsides of these upper inner wall 2a and lower inner wall 2b are surrounded by an outer wall 6 to form a space 8 around the entire periphery of the fuel tank 2. In other words, the outside of the upper inner wall 2a of the fuel tank 2 is surrounded by an upper outer wall 6a, and the outside of the lower inner wall 2b is surrounded by an upper outer wall 6a.
b surrounds the upper space 8a and the lower space 8, respectively.
The upper space 8a and the lower space 8b are filled with an adsorbent 10 made of activated carbon or the like to form an upper adsorption portion 12a and a lower adsorption portion 12b.
2a and the lower suction portion 12b are connected by a communication pipe 14.

In addition, a first
While forming the port 16, the upper suction part 12
A second port 18 is formed in the gas-liquid separator 20.
The first port 16 and the second port 18 are communicated via. Furthermore, a third
A port 22 is formed, a gas-liquid separator 24 is connected to this third port 22, and a bidirectional type valve body 26 is connected, and the valve body 26 is connected to a negative pressure source such as an intake passage of an internal combustion engine (not shown). let The lower suction section 12b is provided with a check valve 28 that opens and closes to introduce atmospheric air into the lower suction section 12b.

Further, in the fuel injection port 30 through which fuel is injected into the fuel chamber 4 of the fuel tank 2, the upper space portion 8a extends to the outer peripheral portion of the fuel injection port 30.
A filter 32 is provided at the outer peripheral end of the upper suction part 12a, and the upper suction part 12a
A is configured to be opened to the atmosphere. In addition, code 34
36 is a fuel injection gun pipe, 38 is a seal cap, and 40 and 42 are O-rings.

Next, the effect will be explained.

As shown in FIG. 3, when the internal combustion engine (not shown) is stopped, first remove the cap 34 of the fuel injection port 30 and insert the fuel injection gun pipe 36 into the fuel injection port 30.
is inserted, and the fuel injection port 30 is closed by a seal cap 38 and O-rings 40, 42 to prevent fuel vapor from being released from the fuel injection port 30 into the atmosphere. By injecting fuel into the fuel tank 2, the gas, mainly fuel vapor, in the fuel chamber 4 of the fuel tank 2 is pressurized by the amount of fuel filled, as shown by the solid arrow in FIG. , is discharged from the first port 16 to the gas-liquid separator 20. and,
The fuel vapor that has passed through the gas-liquid separator 20 is transferred to the second port 1.
8 to the upper suction part 12a, and the upper suction part 1
At the same time, a part of the fuel vapor flows into the lower adsorption section 12b through the communication pipe 14, and is temporarily absorbed by the adsorption agent 10 in the lower adsorption section 12b. It is retained by adsorption. At this time, the air after the fuel vapor has been adsorbed and held is discharged into the atmosphere through the filter 32 of the fuel injection port 30.

Further, by starting an internal combustion engine (not shown), a negative pressure source acts on the valve body 26 to open the valve body 26 and the check valve 28, thereby opening the check valve 28 and the outer peripheral end of the fuel inlet 30. Atmospheric air is introduced into the upper suction section 12a and the lower suction section 12b from the filter 32. And the first
As shown by the broken line arrow in the figure, the upper suction part 12
The fuel adsorbed and held by the lower adsorption part 12b is removed and transferred to the third port 22 and the gas-liquid separator 2.
4. Through the valve body 26, the fuel is introduced into a negative pressure source such as an intake passage of an internal combustion engine (not shown) and combusted.

Furthermore, the upper suction part 12a and the lower suction part 12
When the amount of adsorption of fuel and gas becomes large and the internal pressure of the adsorption section rises, this pressure opens the valve body 26 and introduces fuel vapor into a negative pressure source such as an intake passage of an internal combustion engine. .

As a result, an adsorption part with a large adsorption capacity can be formed on the outer periphery of the fuel tank, and a large amount of fuel vapor generated in the fuel tank can be effectively adsorbed, which is advantageous in practical terms. There is no need to increase the size to increase the size, and it is economically advantageous.

In addition, the adsorption part formed on the outer periphery of the fuel tank can function as a buffer material, which reduces impact force and prevents damage to the fuel tank, which also contributes to preventing fuel from flowing out from the fuel tank. It's something you get.

[Effect of idea]

As explained in detail above, according to this invention, the outside of the fuel tank formed by the inner wall is surrounded by the outer wall to form a space around the entire outer periphery of the fuel tank, and the space is used to provide fuel for injecting fuel into the fuel tank. A filter is provided at the outer peripheral end of the fuel injection port, and an adsorbent is filled in the space to adsorb fuel vapor from the fuel tank, and the space is opened to the atmosphere by the filter. Since an adsorption part having a large adsorption capacity can be formed on the outer periphery of the fuel tank, it is possible to effectively adsorb a large amount of fuel vapor generated in the fuel tank, which is advantageous in practice. , there is no need to increase the size of the canister, which is economically advantageous.
In addition, the suction part on the outer periphery of the fuel tank can function as a buffer material, which can reduce impact force, prevent damage to the fuel tank, and prevent fuel from flowing out from the fuel tank. .

[Brief explanation of the drawing]

Figures 1 to 3 show examples of this invention, Figure 1 is a schematic sectional view of the fuel tank, Figure 2 is a schematic sectional view showing the basic structure of the fuel tank, and Figure 3 is the fuel injection port of the fuel tank. FIG. 2 is a schematic enlarged cross-sectional view. In the illustration, 2 is a fuel tank, 2a is an upper inner wall, 2b is a lower inner wall, 4 is a fuel chamber, 6 is an outer wall, and 8
is a space part, 10 is an adsorbent, 12 is an adsorption part, 14 is a communication pipe, 16 is a first port, 18 is a second port,
20 is a gas-liquid separator, 22 is a third port, 24 is a gas-liquid separator, 20 is a valve body, 28 is a check valve,
30 is a fuel injection port, 32 is a filter, 34 is a cap, 36 is a fuel injection gun pipe, 38 is a seal cap, and 40 and 42 are O-rings.

Claims (1)

[Scope of utility model registration request] The outside of the fuel tank formed by the inner wall is surrounded by the outer wall to form a space around the entire outer periphery of the fuel tank, and this space is extended to the outer periphery of a fuel injection port for injecting fuel into the fuel tank,
A filter is provided at the outer peripheral end of the fuel injection port, and an adsorbent is filled in the space to adsorb fuel vapor from the fuel tank, and an adsorption part is formed which is opened to the atmosphere by the filter. Fuel vapor evaporation prevention device.