JPH07189841A - Vapor fuel processing device - Google Patents

Abstract

PURPOSE:To suppress a the quantity of vapor fuel generated inside a fuel tank so as to miniaturize a canister. CONSTITUTION:A shutter valve 4 opened at the time of inserting an oil supply gun and an elastic seal member 5 sealed along the outer circumferential part of the oil supply gun are provide in the fuel tube 2 of a fuel tank 1. A canister 9 is communicated via a charge passage 6 with the upstream of the shutter 4, Which is downstream side of the elastic seal member 5 of the fuel tube 2. A one-way 10 in which valve opening pressure is comparatively high is arranged on the way of the charge passage 6, and the oneway valve 10 is opened when fuel tank inner pressure is higher than the atmospheric pressure by about 7.3 kilophascal (55mmHg) at the time of fuel supply.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an evaporative fuel treatment system for preventing evaporative fuel generated in a fuel tank of a vehicle from being released to the atmosphere.

[0002]

2. Description of the Related Art FIG. 3 is a diagram showing the structure of a conventional vaporized fuel processing apparatus (for example, Japanese Utility Model Laid-Open No. 5-32065), in which a fuel tube (fuel supply tube) 2 of a fuel tank 1 has an upper portion. In addition, an elastic seal member (for example, a rubber seal member) 5 which is closely attached to the outer peripheral portion of the fuel gun 100 and prevents evaporative fuel from leaking from the fuel filler port at the time of refueling, and the fuel gun 100 is provided downstream of the elastic seal member 5. And a shutter valve 4 that opens when the is inserted. A vaporized fuel intake pipe 3 communicating with the upper portion of the fuel tank 1 is opened on the downstream side of the shutter valve 4 of the fuel tube 2. The downstream side of the elastic seal member 5 of the fuel tube 2 and the upstream side of the shutter valve 4 communicate with a canister 9 having an adsorbent that adsorbs the evaporated fuel via a charge passage 6 for refueling. Further, the upper portion of the fuel tank 1 and the canister 9 are mainly used when the fuel tank 1 is not in operation (when not refueling).
They are connected by a non-lubricating charge passage 7 for supplying the evaporated fuel generated in 1) to the canister 9. Here, the diameter of the charge passage 7 is much smaller than the diameter of the charge passage 6 for refueling. Further, a two-way valve 8 is provided in the middle of the charge passage 7, and the two-way valve 8 is used when the internal pressure of the fuel tank 1 is higher than the atmospheric pressure by a predetermined pressure (for example, 2.7 kPa (20 mmHg)). Open the valve.

The fuel tank 1 and the canister 9 are connected to an engine (not shown).

According to the apparatus of FIG. 3, the shutter valve 4 is opened during refueling, and the fuel tube 2 and the evaporated fuel intake tube 3 are opened.
Further, the evaporated fuel is supplied to the canister 9 via the charging passage 6 for refueling.

On the other hand, when the fuel is not refueled, the shutter valve 4 is closed, so that the evaporated fuel is not supplied to the canister 9 through the refueling charge passage 6, and the pressure in the fuel tank rises. When the pressure becomes higher than the atmospheric pressure by the predetermined pressure or more, the two-way valve 8 opens, and the evaporated fuel is supplied to the canister 9 through the charge passage 7. Further, when the temperature inside the fuel tank 1 decreases and the tank internal pressure falls below the canister internal pressure by a predetermined pressure or more, the two-way valve 8 opens, and in this case, the evaporated fuel is returned to the fuel tank 1.

[0006]

However, in the above-mentioned conventional apparatus, the fuel vapor generated during refueling is sent to the canister through the charge passage having a relatively large cross-sectional area, so the pressure in the fuel tank is atmospheric pressure. It drops to near, and evaporative fuel is easily generated. Therefore, it has been difficult to reduce the size (capacity) of the canister.

The present invention has been made in view of this point, and an object of the present invention is to provide an evaporated fuel processing apparatus capable of suppressing the amount of evaporated fuel generated in the fuel tank and downsizing the canister. And

[0008]

To achieve the above object, the present invention provides a fuel tank having a fuel supply pipe, a canister having an adsorbent for adsorbing fuel vapor generated in the fuel tank, and the fuel supply pipe. A seal member that is disposed in the fuel supply gun and is in close contact with an outer peripheral portion of the fuel gun when the fuel gun is inserted; and a shutter valve that is provided downstream of the seal member of the fuel supply pipe and that opens when the fuel gun is inserted, In an evaporative fuel processing apparatus including a charge passage that is downstream of the seal member and upstream of the shutter valve of the fuel supply pipe and that communicates with the canister, the charge passage has a large pressure inside the fuel tank. A one-way valve that opens when the pressure is higher than a predetermined pressure by a predetermined pressure is provided, or a fuel tank and an adsorbent for adsorbing the evaporated fuel generated in the fuel tank are provided. In a fuel vapor treatment device having a canister and a charge passage communicating the fuel tank with the canister, when the pressure inside the fuel tank is higher than atmospheric pressure by a first predetermined pressure or more in the charge passage. A first one-way valve that opens and a second one-way valve that opens when the pressure in the fuel tank is lower than the pressure in the canister by a second predetermined pressure or more are arranged in parallel. It was done like this.

[0009]

According to the evaporated fuel processing apparatus of the present invention, the shutter valve opens during refueling, and the one-way valve of the charge passage opens when the internal pressure of the fuel tank rises above the atmospheric pressure by a predetermined pressure or more. The vaporized fuel inside is supplied to the canister through the charge passage.

According to the fuel vapor processing apparatus of the second aspect, when the internal pressure of the fuel tank becomes higher than the atmospheric pressure by the first predetermined pressure or more, the first one-way valve in the charge passage is opened while the fuel tank is opened. When the internal pressure becomes lower than the internal pressure of the canister by the second predetermined pressure or more, the second one-way valve opens.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a configuration of an evaporated fuel processing apparatus according to a first embodiment of the present invention, and the same components as those of the apparatus of FIG. 3 described above are designated by the same reference numerals. .

In this embodiment, the charge passage 6 for refueling is used.
A one-way valve 10 is provided midway. The other points are the same as those of the conventional device shown in FIG. The one-way valve 10
With the refueling gun inserted (the shutter valve 4 is opened and the elastic seal member 5 is in close contact with the outer periphery of the refueling gun), the pressure in the fuel tank 1 is lower than the atmospheric pressure by a predetermined pressure (for example, 7.3 kg). The valve opens when the pressure rises above Pascal (55 mmHg).

At the time of refueling, when the refueling gun is inserted, the shutter valve 4 opens and the fuel is supplied to the fuel tank 1.
The air layer in the fuel tank 1 becomes smaller as the fuel is supplied, the pressure in the fuel tank 1 becomes higher, and when the set pressure (valve opening pressure) of the two-way valve 8 is reached, the two-way valve 8 opens, The evaporated fuel is sent to the canister 9. However, since the diameter of the charge passage 7 is small, the pressure increase during refueling cannot be canceled, and the pressure inside the fuel tank further increases. Simultaneously with the above, the evaporated fuel passes through the evaporated fuel intake pipe 3, passes through the gap between the shutter valve 4 and the fuel gun in the fuel tube 2, and reaches the vicinity of the fuel filler port. However, since the fuel gun and the seal 5 are in close contact with each other, evaporation No fuel is released into the atmosphere through the filler opening.

Therefore, the pressure in the fuel tank 1 further rises, and when the set pressure of the one-way valve 10 is reached, the evaporated fuel is sent to the canister 9 through the charge passage 6.
Here, the diameter of the charge passage 6 is much larger than the diameter of the charge passage 7, and the pressure increase due to refueling can be canceled, so that the pressure in the fuel tank 1 is reduced to one
It will never be higher than the set pressure of 0. As described above, the pressure in the fuel tank 1 is kept high during refueling.

After that, when the refueling is completed, the evaporated fuel in the fuel tank 1 gradually passes through the charge passage 7 and the canister 9
The pressure in the fuel tank 1 drops,
The set pressure of the two-way valve 8 is maintained.

As described above, the amount of evaporated fuel generated in the fuel tank 1 can be reduced by maintaining the pressure in the fuel tank 1 at a high pressure during refueling. As a result, the amount of evaporated fuel supplied to the canister 9 is suppressed, and the canister 9 can be downsized (smaller capacity).

FIG. 2 is a diagram showing the structure of an evaporated fuel processing apparatus according to the second embodiment of the present invention.

In this embodiment, the charge passage 6 for refueling is used.
Connects the downstream side of the shutter valve 4 of the fuel tube 2 and the canister 9. A two-way valve 11 is provided in the charge passage 6 instead of the one-way valve 10. Further, the charge passage 7 and the two-way valve 8 when not refueling are deleted.

Except for the above points, it is the same as the first embodiment.

Here, the two-way valve 11 is used when the pressure inside the fuel tank 1 is higher than the atmospheric pressure by a first predetermined pressure (eg, 7.3 kilopascals (55 mmHg)) regardless of whether or not fuel is being supplied. On the other hand, when the pressure in the fuel tank 1 is lower than the pressure in the canister 9 by a second predetermined pressure (eg, 2.7 kPa (20 mmHg)) or more, the valve is opened.

According to this embodiment, the pressure in the fuel tank 1 is maintained at a high pressure regardless of whether fuel is supplied or not, so that the generation of evaporated fuel can be suppressed and the capacity of the canister 9 can be reduced. You can Further, it is not necessary to separately provide a charge passage for non-refueling, and the structure of the device can be simplified.

In the second embodiment, the charge passage 6 may be directly connected to the fuel tank 1 instead of the fuel tube 2. The two-way valve 11 is opened when the internal pressure of the fuel tank is higher than the atmospheric pressure by a first predetermined pressure or more, and is opened when the internal pressure of the canister is higher than the internal pressure of the fuel tank by a second predetermined pressure or more. It can be considered that the second one-way valve for valve is provided in parallel.

Although the second predetermined pressure is set to about 2.7 kPa in the second embodiment, it is not limited to this and may be set to about 7.3 kPa. With such a setting, even if the pressure in the fuel tank 1 drops at low temperatures, it becomes difficult for air in the tank to enter, so the tank internal pressure is maintained at the saturated vapor pressure of the fuel, and the fuel tank 1 is again heated to a high temperature. However, the generation of evaporated fuel can be suppressed.

[0025]

As described in detail above, according to the fuel vapor processing apparatus of the first aspect, the shutter valve opens during refueling, and when the internal pressure of the fuel tank rises above the atmospheric pressure by a predetermined pressure or more, the one-way valve for the charge passage is formed. The valve opens and the evaporated fuel in the fuel tank is supplied to the canister through the charge passage.Therefore, by setting the predetermined pressure to a relatively high pressure, the internal pressure of the fuel tank is kept at a relatively high pressure, Occurrence can be suppressed. As a result, the amount of evaporated fuel supplied to the canister is suppressed, and the canister can be downsized (smaller capacity).

According to the fuel vapor processing apparatus of the second aspect, when the internal pressure of the fuel tank becomes higher than the atmospheric pressure by the first predetermined pressure or more, the first one direction in the charge passage opens while the internal pressure of the fuel tank increases. Is lower than the internal pressure of the canister by a second predetermined pressure or more, the second one-way valve opens, so that the first
The predetermined pressure of 1 is set to a relatively high pressure.
The same effect as that of the device described above can be obtained, and since it is not necessary to provide a charge passage for non-refueling, the structure of the device can be simplified.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an evaporated fuel processing apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of an evaporated fuel processing apparatus according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a conventional evaporated fuel processing device.

[Explanation of symbols]

 1 Fuel Tank 2 Fuel Tube 4 Shutter Valve 5 Elastic Seal Member 6, 7 Charge Passage 8 Two-way Valve 9 Canister 10 One-way Valve 11 Two-way Valve

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location F02M 25/08 H F16K 15/00

Claims (2)

[Claims] 1. A fuel tank having a fuel supply pipe, a canister having an adsorbent for adsorbing evaporated fuel generated in the fuel tank, and an outer circumference of the fuel gun when the fuel gun is inserted into the fuel supply pipe. A seal member that is in close contact with the fuel supply pipe, a shutter valve that is disposed on the fuel supply pipe downstream of the seal member, and opens when a fueling gun is inserted; In the vaporized fuel processing device including a charge passage that connects the shutter valve upstream side and the canister, a one-way valve that opens when the pressure in the fuel tank is higher than atmospheric pressure by a predetermined pressure or more is provided in the charge passage. An evaporative fuel treatment device, which is provided. 2. An evaporative fuel processing apparatus comprising: a fuel tank; a canister having an adsorbent for adsorbing evaporated fuel generated in the fuel tank; and a charge passage communicating with the fuel tank and the canister. The charge passage has a first one-way valve that opens when the pressure in the fuel tank is higher than the atmospheric pressure by a first predetermined pressure or more, and a pressure in the fuel tank that is second than the pressure in the canister. An evaporative fuel treatment apparatus, wherein a second one-way valve that opens when the pressure is lower than a predetermined pressure is arranged in parallel.