JP2002235609A - Evaporated fuel treatment device for internal combustion engine provided with supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an evaporated fuel treatment device for an internal combustion engine provided with a supercharger for easily supplying evaporated fuel adsorbed by a canister to the internal combustion engine even when intake pipe pressure is higher than atmospheric pressure in a supercharge zone, and especially in a vehicle of a small exhaust quantity such as a light car, positively supplying evaporated fuel adsorbed by the canister to the internal combustion engine even when the supercharging zone is frequently used. SOLUTION: A throttle valve is provided in an intake passage between the supercharger and the internal combustion engine, and a supercharging air passage is provided on the intake passage between the throttle valve and the supercharger to be communicated with an atmospheric air introducing passage. A three-way change-over valve provided with an atmospheric air intake port is provided between the supercharging air passage and the atmospheric air introducing passage, and this three-way change-over valve is changed to communicate the supercharging air passage with the atmospheric air introducing passage when the intake pipe pressure on the downstream of the supercharger is higher than the atmospheric pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaporative fuel processor for an internal combustion engine with a supercharger, and more particularly to a supercharger for purging evaporative fuel generated in a fuel tank in an internal combustion engine with a supercharger. The present invention relates to a fuel vapor treatment device for an internal combustion engine with a compressor.

[0002]

2. Description of the Related Art In a vehicle, as shown in FIG.
This evaporative fuel processing device 204 is provided with an evaporative fuel passage 204 that adsorbs and holds the evaporative fuel from the fuel tank 206 between an evaporative passage 208 communicating with the fuel tank 206 and a purge passage 210 that communicates with the internal combustion engine 202. At the same time, during operation of the internal combustion engine 202, a canister that introduces the atmosphere from the atmosphere introduction passage 212 using the difference in air pressure, that is, the difference between the intake pipe negative pressure and the atmospheric pressure, and supplies the adsorbed and held evaporated fuel to the internal combustion engine 202 In the middle of the purge passage 210, a purge valve 216 for adjusting the flow rate of the purge gas to the internal combustion engine 202 is provided. As described above, some internal combustion engines of vehicles provided with the evaporative fuel treatment device include a supercharger, and the supercharger is provided in an intake passage for guiding air from an air cleaner to the internal combustion engine. ing.

[0003] Such an evaporative fuel processing apparatus for an internal combustion engine is disclosed in, for example, JP-A-11-182370 and JP-A-6-307297. Japanese Unexamined Patent Publication No. 11-182370 discloses a supercharging pressure introducing passage which branches from an intake passage between a supercharger and a throttle valve and communicates with a canister. A cut valve is provided, and an air cut valve is provided at the air inlet of the canister.The canister is purged with supercharged air in the supercharged region, and canister purge is performed using the intake negative pressure in the non-supercharged region. Is what you do. Japanese Unexamined Patent Publication No. Hei 6-307297 discloses a supercharging pressure introducing passage which branches from an intake passage between a supercharger and a throttle valve and communicates with a canister. A pressure control valve, a switching valve, and a ventilation valve are sequentially provided from the side.

[0004]

However, in the conventional evaporative fuel treatment apparatus for a supercharged internal combustion engine, in the supercharging region, the intake pipe pressure becomes higher than the atmospheric pressure and the intake pipe negative pressure becomes lower. Therefore, it becomes difficult to suck the evaporated fuel adsorbed in the canister into the intake passage, and particularly in a small displacement vehicle such as a mini vehicle, the tendency is remarkable because the supercharged region is frequently used. There was an inconvenience of becoming.

[0005]

SUMMARY OF THE INVENTION Therefore, in order to eliminate the above-mentioned disadvantages, the present invention provides an intake passage for guiding air from an air cleaner of a vehicle to an internal combustion engine, and provides a supercharger in the middle of the intake passage. The fuel tank of the vehicle communicates with an evaporative passage and a purge passage that communicates with the internal combustion engine by adsorbing and holding fuel vapor from the fuel tank and utilizing a pressure difference during operation of the internal combustion engine. A canister for introducing the atmosphere from the atmosphere introduction passage to supply the vaporized fuel adsorbed and held to the internal combustion engine, and a purge valve for adjusting a flow rate of a purge gas to the internal combustion engine is provided in the purge passage. In the evaporative fuel processing device for a charged internal combustion engine, a throttle valve is provided in the intake passage between the supercharger and the internal combustion engine, and the suction valve between the throttle valve and the supercharger is provided. A supercharged air passage communicating with the air introduction passage is provided in the passage, and a three-way switching valve provided with an air intake port is provided between the supercharged air passage and the air introduction passage. The directional control valve switches communication between the supercharged air passage and the air introduction passage when an intake pipe pressure downstream of the supercharger is higher than atmospheric pressure.

[0006]

According to the present invention, when the intake pipe pressure on the downstream side of the supercharger is higher than the atmospheric pressure, the three-way switching valve switches communication between the supercharged air passage and the air introduction passage, The high-pressure supercharged air in the intake passage between the supercharger and the throttle valve reaches the canister via the supercharged air passage and the atmosphere introduction passage, and
The fuel vapor adsorbed by the canister is purged, and the purged purge gas is adjusted from a purge passage by a purge valve and supplied to the internal combustion engine. Thereby, in the supercharging region, even if the intake pipe pressure becomes higher than the atmospheric pressure, the evaporated fuel adsorbed by the canister is easily supplied to the internal combustion engine side. Even if the supercharging region is frequently used, the fuel vapor adsorbed by the canister can be positively supplied to the internal combustion engine.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; 1 and 2 show a first embodiment of the present invention. In FIG. 2, reference numeral 2 denotes an internal combustion engine with a supercharger mounted on a vehicle, 4 denotes a supercharger, and 6 denotes a fuel tank. The internal combustion engine 2 is provided with an intake manifold 8 connected as an intake system. This intake manifold 8
Is provided with a throttle body 12 having a throttle valve 10. An intake pipe 18 having an intake passage 16 communicating with an air cleaner 14 is formed in the throttle body 12.
Are connected to each other. An intake passage 16 communicating the internal combustion engine 2 and the air cleaner 14 is provided with an intake pipe 18.
And the throttle body 12 and the intake manifold 8.

In the middle of the intake pipe 18, a supercharger 4 is provided. Although not shown, the supercharger 4 includes an intake pipe 18.
It consists of a compressor provided in the middle and a turbine provided in the middle of the exhaust pipe, and rotates by the pressure of the exhaust gas to pressurize the intake air.

[0009] Fuel tank 6 and intake manifold 8 of the intake system
Between them, an evaporative fuel processing device 20 for processing the evaporative fuel generated in the fuel tank 6 is provided.

In this evaporative fuel processing apparatus 20, the evaporative fuel from the fuel tank 6 is supplied between an evaporative passage 22 communicating with the fuel tank 6 and a purge passage 24 communicating with the intake manifold 8 on the internal combustion engine 2 side. While the internal combustion engine 2 is being operated, the vaporized fuel adsorbed and retained is introduced into the internal combustion engine 2 by utilizing the difference in air pressure during the operation of the internal combustion engine 2, that is, the difference between the intake pipe negative pressure and the atmospheric pressure. Is provided.

A purge valve (duty solenoid valve) 30 for adjusting the flow rate of the purge gas to the internal combustion engine 2 is provided in the middle of the purge passage 24. The purge valve 30 is controlled by the control means 50 in accordance with the operating state of the internal combustion engine 2.

The intake pipe 18 forming the intake passage 16 between the throttle valve 10 and the supercharger 4 is provided with a supercharged air passage 32 communicating with the air introduction passage 26 of the canister 28. . A three-way switching valve (three-way switching valve: VSV) provided with an air suction port 34 between the supercharged air passage 32 and the air introduction passage 26.
36 are provided.

When the intake pipe pressure in the intake passage 16 downstream of the supercharger 4 is higher than the atmospheric pressure, the three-way switching valve 36 shuts off the air intake port 34 and connects to the supercharged air passage 32. When the intake pipe pressure of the intake passage 16 downstream of the supercharger 4 is lower than the atmospheric pressure, the supercharged air passage 32 is shut off and the air intake port 34 is switched.
And the air introduction passage 26 for switching communication.

When the three-way switching valve 36 switches communication between the supercharged air passage 32 and the atmosphere introducing passage 26, the evaporating passage 22 between the fuel tank 6 and the canister 28 is switched from the canister 28 side. An evaporative side one-way valve (one-way valve) 38 for preventing the supercharged air from flowing back to the fuel tank 6 side is provided.

In a purge passage 24 between the canister 28 and the intake manifold 8 on the internal combustion engine 2 side, a purge side one-way valve () for preventing supercharged air from the internal combustion engine 2 from flowing back to the canister 28 side. A one-way valve 40 is provided.

Between the fuel tank 6 and the intake passage 16 on the upstream side of the supercharger 4, when the evaporative one-way valve 38 of the evaporative passage 22 is closed, the evaporated fuel in the fuel tank 6 is discharged. An evaporative bypass passage 42 leading to the intake passage 16 on the upstream side of the feeder 4 is provided. This evaporative bypass passage 42
Is connected to an intake passage 16 near the supercharger 4.

The evaporative bypass passage 42 prevents the amount of purge from the canister 28 from being too large and prevents the inside of the fuel tank 6 from being in a negative pressure state, and the fuel vapor in the fuel tank 6 when the internal combustion engine 2 is stopped. One-way control valve (one-way solenoid valve) to prevent air from being released to the atmosphere
44 are provided. The one-way control valve 44 can switch and control the communication state of the evaporation bypass passage 42 and the one-way valve state of permitting only the ventilation from the intake passage 16 side to the fuel tank 6 side.

In the evaporative fuel processing apparatus 20,
A tank pressure sensor 46 for detecting a tank internal pressure in the fuel tank 6 and an intake pipe pressure sensor 48 for detecting an intake pipe pressure are provided. In the first embodiment, in order to purge the canister 28, the intake pipe pressure sensor 48 detects the pressure of the air in the intake passage 16 in the intake pipe between the supercharger 4 and the throttle valve 10. ing. However, when purging in consideration of the operating state of the internal combustion engine 2, it is also possible to detect and control the pressure of the air in the intake manifold 8 downstream of the throttle valve 10 by using the intake pipe pressure sensor 48.

The purge valve 30, the three-way switching valve 36, the one-way control valve 44, the tank pressure sensor 46, and the intake pipe pressure sensor 48 communicate with the control means 50 and are controlled by the control means 50.

During the purge control, the control means 50 controls the operation of the purge valve 30 to adjust the purge flow rate, and also controls the tank in the fuel tank 6 to prevent the inside of the fuel tank 6 from being in a negative pressure state. When the internal pressure becomes equal to or less than a predetermined value (for example, equal to or less than the atmospheric pressure) or when the internal combustion engine 2 is stopped, the one-way control valve 44 allows the one-way control valve 44 to allow only the ventilation from the intake passage 16 side to the fuel tank 6 side. Is closed.

Next, the operation of the first embodiment will be described with reference to the flowchart of FIG.

When the purge control is started by the control means 50 (step 102), it is determined whether or not the intake pipe pressure is higher than the atmospheric pressure (step 104).

If step 104 is YES and the intake pipe pressure is higher than the atmospheric pressure, the three-way switching valve 36 is operated to shut off the air intake port 34 and to switch the supercharged air passage 32 and the atmosphere introduction passage. 34, the intake passage 16, the supercharged air passage 32, and the air introduction passage 26 on the downstream side of the supercharger 4.
And the canister 28 (step 106).

Then, it is determined by the tank pressure sensor 46 whether or not the tank pressure in the fuel tank 6 is positive (step 108).

If step 108 is YES and the tank pressure in the fuel tank 6 is positive, the one-way control valve 44
To make the evaporative bypass passage 42 communicate with the fuel tank 6 and the intake passage 16 on the upstream side of the supercharger 4 so that the fuel vapor accumulated in the fuel tank 6 is removed from the supercharger 4. The air is discharged to the upstream intake passage 16 (step 11
0). Then, the purge flow rate of the purge gas is adjusted by the purge valve 30 (step 112), and it is determined whether the purge control is to be terminated (step 114).

If step 114 is YES and the purge control is to be terminated, the three-way switching valve 36 is switched to shut off the supercharged air passage 32 and switch between the air suction port 34 and the air introduction passage 26. Communication and one-way control valve 4
4 is switched to a one-way valve state in which only ventilation from the intake passage 16 side to the fuel tank 6 side is permitted (step 11
6) Then, the purge control ends (step 11).
8).

If the answer in step 104 is NO and the intake pipe pressure is lower than the atmospheric pressure, the three-way switching valve 36 is switched to shut off the supercharged air passage 32 and to connect the air intake port 34 and the air introduction passage. And 26 (step 120).
Then, the process proceeds to step 112.

If NO in step 108 and the tank pressure in the fuel tank 6 is negative, the one-way control valve 44 is switched to the one-way valve state (step 12).
2) Then, the process proceeds to step 112.

If the answer to step 114 is NO and the purge control is not to be ended, the routine returns to step 104.

As a result, in the supercharging region, even if the internal pressure of the intake pipe becomes higher than the atmospheric pressure, the fuel vapor adsorbed by the canister 28 can be easily purged to the internal combustion engine 2 side. Even in a small-volume vehicle, the fuel vapor adsorbed by the canister 28 can be positively supplied to the internal combustion engine 2 even if the supercharging region is frequently used.

An evaporative side one-way valve 38 is provided in the evaporative passage 22 between the fuel tank 6 and the canister 28, so that the three-way switching valve 36 switches and connects the supercharged air passage 32 and the atmosphere introduction passage 26. At this time, it is possible to prevent the supercharged air from the canister 28 from flowing back to the fuel tank 6 side.

A purge side one-way valve 40 is provided in the purge passage 24 between the canister 28 and the internal combustion engine 2 to prevent supercharged air from the internal combustion engine 2 from flowing back to the canister 28. be able to.

If the one-way valve 38 on the evaporation side of the evaporation passage 22 is closed in the supercharging state, and the state in which the evaporated fuel cannot be discharged using the evaporation passage 22 continues for a long time, the evaporation in the fuel tank 6 will occur. Although the fuel tends to accumulate, the evaporative bypass passage 42 is provided between the fuel tank 6 and the intake passage 16 on the upstream side of the supercharger 4 so that the fuel vapor in the fuel tank 6 can be removed from the supercharger 4. To the intake passage 16 on the upstream side of the supercharger 4, and can be sucked into the supercharger 4. Thus, it is possible to prevent the malfunction of the internal combustion engine 2 caused by the rapid release of the fuel vapor accumulated in the fuel tank 6 when the supercharging state is stopped. Further, since the evaporative bypass passage 42 is connected to the intake passage 16 near the supercharger 4, the evaporative fuel in the fuel tank 6 is positively utilized by positively utilizing the air suction by the supercharger 4. It is also possible to perform aspiration.

A one-way control valve 44 is provided in the evaporative bypass passage 42 to control the switching between the communicating state and the one-way valve state, so that the amount of purge from the canister 28 is too large and the inside of the fuel tank 6 is in a negative pressure state. To prevent the fuel tank 6 from being deformed, and prevent the fuel vapor in the fuel tank 6 from being released to the atmosphere when the internal combustion engine 2 is stopped.

A tank pressure sensor 46 for detecting the tank internal pressure in the fuel tank 6 is provided. When the tank internal pressure in the fuel tank 6 becomes lower than the atmospheric pressure, the one-way control valve 44 is moved from the intake passage 16 side to the fuel tank. By switching to the one-way valve state in which only ventilation to the side 6 is permitted, the inside of the fuel tank 6 can be prevented from being in a negative pressure state.

FIG. 3 shows a second embodiment of the present invention.

In the following embodiment, portions having the same functions as those in the above-described first embodiment will be described with the same reference numerals.

The features of the second embodiment are as follows. That is, the evaporative side three-way control valve 52 is provided in the middle of the evaporative passage 22, and the evaporative side three-way control valve 52 is provided.
Is provided with an evaporation bypass passage 42 connected thereto.

According to the structure of the second embodiment, the number of the evaporative passages connected to the fuel tank 6 is reduced, and even if the state in which the evaporative fuel cannot be discharged using the evaporative passages 22 continues for a long time, Evaporated fuel accumulated in the fuel tank 6 can be discharged to the intake passage 16 on the upstream side of the supercharger 4, and the amount of purge from the canister 28 is too large due to the evaporation-side three-way control valve 52, so that the fuel tank 6 Can be prevented from being in a negative pressure state, and the fuel vapor in the fuel tank 6 can be prevented from being released to the atmosphere when the internal combustion engine 2 is stopped.

FIG. 4 shows a third embodiment of the present invention.

The features of the third embodiment are as follows. That is, the evaporated fuel processing apparatus 2 of the first embodiment
In the configuration of No. 0, the evaporation bypass passage 42 and the one-way control valve 44 are omitted.

According to the configuration of the third embodiment, the configuration of the evaporated fuel processing device 20 is simplified, and the evaporated fuel adsorbed by the canister 28 can be easily supplied to the internal combustion engine.

FIG. 5 shows a special structure of the present invention.
It shows an embodiment.

The features of the fourth embodiment are as follows. That is, an auxiliary bypass passage 64 is provided to connect the fuel tank 6 with the evaporation passage 22 on the fuel tank 6 side of the evaporation one-way valve 38, and the auxiliary bypass passage 64 holds a second evaporating fuel. Canister 64
Is provided, and the fuel tank 6 is provided more than the second canister 64.
The auxiliary side bypass passage 64 is provided with an auxiliary side first one-way valve 66 that allows a flow from the fuel tank 6 side to the second canister 64, and is located closer to the evaporation side one-way valve 38 than the second canister 64. The auxiliary-side bypass passage 64 is provided with an auxiliary-side second one-way valve 68 that allows a flow from the second canister 64 to the evaporation-side one-way valve 38.

According to the configuration of the fourth embodiment, when excessive fuel vapor is generated in the fuel tank 6, the auxiliary first
When the one-way valve 66 is opened, the evaporated fuel is discharged to the second
Is stored in the canister 64, and the auxiliary second one-way valve 68 is opened depending on the operation state of the internal combustion engine 2, so that the fuel vapor in the second canister 64 flows toward the main canister 28, and It is possible to prevent the fuel from flowing out. Further, when the fuel vapor is excessively generated in the fuel tank 6, there is no need to guide the fuel vapor to the intake system side, and the bypass passage can be omitted and the configuration can be simplified.

FIG. 6 shows a special structure of the present invention.
It shows an embodiment.

The features of the fifth embodiment are as follows. That is, a motor pump 72 for supplying pressurized air to the canister 28 is provided in the atmosphere introduction passage 26, and an atmosphere port side one-way valve 74 is provided on the atmosphere port side of the motor pump 72. A canister-side one-way valve 76 is provided closer to the canister 28 than to 72.

According to the configuration of the fifth embodiment, in the supercharging region of the internal combustion engine 2, pressurized air higher than the supercharging pressure (intake pipe pressure) in the intake passage 16 is sent to the canister 28, and By supplying the fuel vapor inside the intake passage 16 to the intake passage 16, pressurized air in the intake pipe and its piping are not required, and the fuel vapor inside the canister 28 can be purged at an appropriate time at any time.

According to the present invention, for example, when the throttle opening is rapidly increased, the amount of supercharged air from the supercharged air passage 32 is increased to purge the fuel vapor in the canister 28. It is also possible to increase the purge amount.

[0050]

As apparent from the above detailed description, according to the present invention, a throttle valve is provided in the intake passage between the supercharger and the internal combustion engine, and the intake air between the throttle valve and the supercharger is provided. A supercharged air passage communicating with the air introduction passage is provided in the passage, and a three-way switching valve provided with an air suction port is provided between the supercharged air passage and the air introduction passage. When the intake pipe pressure on the downstream side of the supercharger is higher than the atmospheric pressure, the valve switches between the supercharged air passage and the air introduction passage so that the intake pipe pressure in the supercharged region is lower than the atmospheric pressure. Even if it gets higher,
The evaporative fuel adsorbed by the canister is easily supplied to the internal combustion engine side, so that even in a small displacement vehicle such as a mini vehicle, the evaporative fuel adsorbed by the canister can be supplied to the internal combustion engine even when the supercharged region is frequently used. Agencies can be actively supplied.

[Brief description of the drawings]

FIG. 1 is a flowchart of evaporative fuel processing control.

FIG. 2 is a system configuration diagram of an evaporative fuel processing apparatus.

FIG. 3 is a system configuration diagram of an evaporative fuel processing apparatus according to a second embodiment.

FIG. 4 is a system configuration diagram of a fuel vapor processing apparatus according to a third embodiment.

FIG. 5 is a partial configuration diagram of a system of a fuel vapor processing apparatus according to a fourth embodiment.

FIG. 6 is a partial configuration diagram of a system of a fuel vapor processing apparatus according to a fifth embodiment.

FIG. 7 is a system configuration diagram of a conventional evaporated fuel processing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 2 Internal combustion engine 4 Supercharger 6 Fuel tank 8 Intake manifold 10 Throttle valve 16 Intake passage 20 Evaporation fuel processor 22 Evaporation passage 24 Purge passage 28 Canister 30 Purge valve 32 Supercharged air passage 36 Three-way switching valve 38 One-way on the evaporation side Valve 40 Purge-side one-way valve 42 Evaporative bypass passage 44 One-way control valve 46 Tank pressure sensor 48 Intake pipe pressure sensor 50 Control means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02M 25/08 311 F02M 25/08 311G F02D 43/00 301 F02D 43/00 301M 301R

Claims (7)

[Claims] An intake passage for guiding air from an air cleaner of a vehicle to an internal combustion engine is provided, a supercharger is provided in the middle of the intake passage, and an evaporative passage communicating with a fuel tank of the vehicle and the internal combustion engine are communicated. In between the purge passage, the vaporized fuel from the fuel tank is adsorbed and held, and during the operation of the internal combustion engine, air is introduced from the air introducing passage by utilizing the difference in air pressure, and the adsorbed and held vaporized fuel is discharged. An evaporative fuel processing apparatus for a supercharged internal combustion engine, further comprising a canister for supplying an internal combustion engine, and a purge valve provided in the middle of the purge passage for adjusting a flow rate of a purge gas to the internal combustion engine. A throttle valve is provided in the intake passage between the engine and the engine, and a supercharged air passage communicating with the air introduction passage is provided in the intake passage between the throttle valve and the supercharger. A three-way switching valve provided with an air intake port is provided between the air passage and the atmosphere introduction passage, and the three-way switching valve has an intake pipe pressure downstream of the supercharger that is lower than atmospheric pressure. An evaporative fuel processing apparatus for an internal combustion engine with a supercharger, characterized in that when high, the supercharged air passage and the air introduction passage are switched and communicated. 2. When the three-way switching valve switches communication between the supercharged air passage and the atmosphere introduction passage, the evaporative passage between the fuel tank and the canister is connected to the evaporative passage.
2. An evaporative fuel processing apparatus for an internal combustion engine with a supercharger according to claim 1, further comprising an evaporation side one-way valve for preventing supercharged air from said canister from flowing back to said fuel tank. . 3. A purge one-way valve for preventing a supercharged air from the internal combustion engine from flowing back to the canister is provided in the purge passage between the canister and the internal combustion engine. The evaporative fuel processing apparatus for a supercharged internal combustion engine according to claim 1, wherein: 4. An evaporative bypass passage between the fuel tank and the intake passage on the upstream side of the supercharger, the communication passage being provided between the fuel tank and the intake passage on the upstream side of the supercharger. The evaporative fuel processing apparatus for an internal combustion engine with a supercharger according to claim 1, further comprising: 5. A one-way valve is provided in the evaporation bypass passage to prevent the fuel vapor in the fuel tank from being discharged to the intake passage when the internal combustion engine is stopped. Item 5. An evaporative fuel treatment device for an internal combustion engine with a supercharger according to Item 4. 6. A one-way control valve is provided in the evaporative bypass passage so as to switch between a communicating state of the evaporative bypass passage and a one-way valve state permitting only ventilation from the intake passage side to the fuel tank side. 5. The evaporative fuel treatment apparatus for a supercharged internal combustion engine according to claim 4, wherein: 7. A tank pressure sensor for detecting a tank internal pressure in the fuel tank, wherein the tank internal pressure in the fuel tank is reduced to a predetermined value or less in order to prevent the inside of the fuel tank from being in a negative pressure state. 7. The apparatus according to claim 6, further comprising control means for switching the one-way control valve to a one-way valve state.