JPH06147030A - Fuel vaporized gas discharge restraining device - Google Patents

Abstract

PURPOSE:To prevent the deterioration of adsorbent and miniaturize a canistor for its adsorption capacity by mounting a liquefaction promoting member to in a gas-liquid separation chamber to forcedly perform the liquefaction separa tion for a high boiling component included in vaporized fuel, and also efficiently gasifying liquefied fuel at the time of a purge to reduce the load of adsorbent in a canistor. CONSTITUTION:In this fuel vaporized gas discharge restraining device, a gas- liquid separation chamber 5 is formed in a vessel 3 for a canistor, a fibrous or strip-like liquefaction promoting member 12 is mounted on the upper part in the gas-liquid separation chamber 5, the lower part in the gas-liquid separation chamber 5 is made a reserving chamber 11 for separated liquid fuel, and the gas-liquid separation chamber 5 is communicated with the adsorbent housing chamber 6 of the canistor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel evaporative emission control device for preventing the evaporative fuel from being released into the atmosphere by absorbing the fuel evaporated from a fuel tank or the like in a vehicle such as an automobile. It is about.

[0002]

2. Description of the Related Art Conventionally, vaporized fuel generated in a fuel tank or the like of a vehicle such as an automobile is temporarily adsorbed by activated carbon in a canister so as not to be released into the atmosphere. To desorb the evaporated fuel adsorbed on the activated carbon (per
(2) A fuel evaporative emission control device is well known in which the fuel evaporative emission control is performed so that the fuel evaporative emission is burned by being supplied to the intake pipe side of the engine.

By the way, in recent years, with increasing concern about global environmental problems on a global scale, the regulation value for preventing the emission of fuel evaporative emissions generated from vehicles to the atmosphere has been further strengthened. . Against this background, the canisters are required to have sufficient adsorption / desorption performance for collecting a large amount of vaporized gas due to the stricter regulations. In order to satisfy this requirement, the adsorbent capacity has to be simply increased in the conventional canister structure, so that the canister must inevitably be upsized, and it is difficult to mount it on an actual vehicle.

Here, the performance required of the canister is, of course, the point that the adsorbing capacity of the adsorbent adsorbs the evaporated fuel, and the adsorbed fuel is adsorbed as much as possible at the time of purging. How to regenerate the adsorbent by desorption is also an important point. However, the adsorbents currently used in canisters cannot desorb all of the adsorbed substances in the process of repeatedly adsorbing and desorbing evaporative gas, and the pores of the adsorbent gradually increase with each adsorbing and desorbing process. The components that could not be desorbed accumulate inside and reduce the performance of the canister. Therefore, it is necessary to fill the larger amount of adsorbent in consideration of this performance deterioration, which leads to the increase in size of the canister.

By the way, if the amount that remains in the adsorbent without being fully desorbed (remaining amount) is reduced as much as possible, the adsorbent filling amount can be reduced and the canister can be downsized. The factors that affect the remaining amount are, for example, the amount of steam generated on the vehicle side, the component of evaporated fuel, or the amount of air during purging, depending on the characteristics of the adsorbent. When focusing on the components of the vaporized fuel, the low boiling point components in the vaporized fuel are relatively easily desorbed even if they are adsorbed by the adsorbent, but in the case of high boiling point components, it is difficult to desorb and desorb them. It will not be exhausted and will remain. Further, when liquid fuel adheres to the adsorbent, it deteriorates early. Therefore, in order to avoid the deterioration of the adsorbent, it has been attempted to liquefy the high-boiling point component upstream of the adsorbent and provide a gas-liquid separator to adsorb only the evaporated fuel of the low-boiling point component to the adsorbent. (For example, actual exploitation Sho 63-104659
(See Japanese Utility Model Publication No. 1-131858).

[0006]

By the way, in the case of the above-mentioned conventional example, since the gas-liquid separation is performed by simple bending of the fluid, the liquid particles contained in the evaporated fuel can be separated to some extent. However, it is not possible to sufficiently liquefy and separate the vaporized high-boiling components, and the separated liquid fuel is vaporized by a heating heater or returned to the fuel tank, so an extra heating device is required. It requires heat energy and extra piping for returning to the fuel tank.

The present invention has been made in view of the above problems, and an object of the present invention is to install a liquefaction promoting member in the gas-liquid separation chamber and to increase the amount of fuel contained in the evaporated fuel. In addition to forcibly liquefying the boiling point components, the liquefied fuel is efficiently vaporized at the time of purging to reduce the load on the adsorbent in the canister and prevent the adsorbent from deteriorating. An object of the present invention is to provide a fuel evaporative emission control device in which the canister is downsized.

[0008]

In order to achieve the above object, a fuel evaporative emission control device according to the present invention forms a gas-liquid separation chamber in a container of a canister, and a fibrous material is formed above the gas-liquid separation chamber. Alternatively, a strip-shaped liquefaction promoting member is attached, the lower part of the gas-liquid separation chamber serves as a storage chamber for the separated liquid fuel, and the gas-liquid separation chamber communicates with the adsorbent storage chamber of the canister. .

Further, a gas-liquid separation chamber is formed in the canister container, an upper part of the gas-liquid separation chamber is a liquefaction promoting chamber and a lower part is a storage chamber for the separated liquid fuel, and the liquid fuel is sucked into the storage chamber by a capillary phenomenon. It is also characterized in that a vaporization promoting member consisting of is attached and the gas-liquid separation chamber is communicated with the adsorbent storage chamber of the canister.

Furthermore, a gas-liquid separation chamber is formed in the canister container, an upper part of the gas-liquid separation chamber is a liquefaction promoting chamber, a lower part is a storage chamber for the separated liquid fuel, and a tank internal pressure is provided at an upper end part of the gas-liquid separation chamber. It is also characterized in that the discharge port of the control valve and the inflow port of the purge valve are provided close to each other, and the gas-liquid separation chamber is communicated with the adsorbent storage chamber of the canister.

[0011]

According to the above construction, the evaporated fuel generated in the fuel tank enters the gas-liquid separation chamber from the vapor fuel passage. The liquid particles contained in the vaporized fuel are captured and separated by the liquefaction promoting member in the gas-liquid separation chamber, and the high-boiling-point components in the vaporized fuel are also cooled and liquefied. It is stored. In this way, the liquid particles contained in the evaporated fuel and the evaporated fuel from which the high boiling point components in the evaporated fuel have been removed are adsorbed by the adsorbent in the canister.

When the engine is operated and the purge valve is opened at an appropriate time, the negative pressure in the intake pipe causes atmospheric air to enter the canister to desorb the vaporized fuel adsorbed by the adsorbent, and the vaporized fuel is desorbed. And is supplied to the intake pipe side of the engine through the gas-liquid separation chamber. Then, while this atmosphere enters the gas-liquid separation chamber 5 and passes through the vaporization promoting member, the vaporization promoting member vaporizes the liquid fuel sucked up from the reservoir chamber by a capillary phenomenon over a wide range.

Further, when the tank internal pressure control valve is opened when the purge valve is opened, the evaporated fuel from the fuel tank is discharged from the control valve and the inlet of the purge valve. Since they are close to each other, they are supplied to the intake pipe side of the engine through the control valve, the upper end of the gas-liquid separation chamber, and the purge valve without being adsorbed by the adsorbent of the canister, and the burden on the canister is reduced accordingly. .

[0014]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is an overall view of a fuel evaporative emission control device according to an embodiment of the present invention, and FIG. 2 is a detailed view of a gas-liquid separation chamber. In the figure, reference numeral 1 is a gasoline fuel tank mounted on a vehicle, and vaporized fuel in the gas phase portion is formed in the canister container 3 from an introduction port 4 of the canister container 3 through a vapor fuel pipe 2. It is adapted to be introduced into the gas-liquid separation chamber 5. A tank internal pressure control valve V1 is provided between the steam fuel pipe 2 and the introduction port 4, and the tank internal pressure is controlled by the control valve V1 when the engine is stopped and the engine is operating. is there.

In the adsorbent storage chamber 6 of the canister container 3, adsorbents 7 made of activated carbon or the like are stored in layers.
Reference numerals 8 and 9 denote a filter and a perforated plate for holding both ends of the adsorbent layer, and a chamber 10 for introducing vaporized fuel into the liquid fuel storage chamber of the gas-liquid separation chamber 5 at the lower end side of the first adsorbent layer 7a. It is formed by opening at 11. The liquid fuel separated by the liquefaction promoting member 12 mounted in the upper part of the gas-liquid separation chamber 5 and the liquid fuel liquefied by the member are stored in the storage chamber 11 in the lower part of the gas-liquid separation chamber 5 and are almost Only the evaporated fuel is introduced from the introduction chamber 10 to the adsorbent storage chamber 6. The wall 10a at the lower end of the first adsorbent layer 7a is formed in an inclined shape so that a part of the liquid fuel that is about to be entrained in the adsorbent storage chamber 6 by the evaporated fuel is returned to the storage chamber 11. There is. The final adsorbent layer 7b in the adsorbent storage chamber 6 communicates with the atmosphere from the atmosphere port 13 via a vent valve (electromagnetic valve) V2. The solenoid valve V2 is normally open, and may be closed by energization when diagnosing a failure of the evaporation system, for example. In addition, the gas-liquid separation chamber 5 has a purge pipe 14
Through the intake pipe 15 of the engine, and a purge valve V3 is provided between the purge pipe 16 at the upper end of the gas-liquid separation chamber 5 and the purge pipe 14, Tube 1
It is designed to control the purge flow rate to 5. The tank internal pressure control valve V1, the vent valve V2, and the purge valve V3 are arranged in the canister container 3, and the discharge port 17 of the tank internal pressure control valve V1 is the introduction port.
Projecting from the gas chamber 4 into the gas-liquid separation chamber 5 and the purge valve V3
The inflow port 18 of the above projects from the purge port 16 into the gas-liquid separation chamber 5, and the discharge port 17 and the inflow port 18 are arranged close to each other at the upper end of the gas-liquid separation chamber 5.

The liquefaction promoting member 12 mounted on the upper part of the gas-liquid separation chamber 5 is to capture the liquid particles contained in the evaporated fuel and to cool and liquefy the high boiling point components in the evaporated fuel. It is preferable to use a metal or resin material such as stainless steel or aluminum or the like, which is formed into a fibrous shape or a strip shape so that the above can be achieved. FIG. 3 shows the relationship between the filling weight of the liquefaction promoting member and the weight of the liquefied gasoline, which is confirmed by experiments for the liquefaction promoting effect of these materials. According to this figure, the weight of liquefied gasoline is initially increased as the filling amount of the liquefaction promoting member is increased. In addition, the amount of liquefaction promoting members to be filled has good liquefaction efficiency, but when the filling amount exceeds a certain amount, the liquefaction promoting members will overlap with each other, and the surface area where the evaporated fuel contacts will decrease. As shown in FIG.
It is recommended to determine the filling amount of the liquefaction promoting member with good liquefaction efficiency by referring to. Further, when the liquefaction promoting member 12 is attached to the gas-liquid separation chamber 5, there is a risk that the evaporated gas desorbed from the adsorbent may collide with the liquefaction promoting member 12 at the time of purging and liquefy again. When the engine is running,
Even if it is liquefied, it is immediately vaporized by the purge air and introduced into the intake pipe 15, so there is no particular problem.

A vaporization promoting member 19 is mounted in the storage chamber 11 below the gas-liquid separation chamber 5. The vaporization promoting member 19 is made of a material that sucks up the liquid fuel 20 stored in the storage chamber 11 by a capillary phenomenon. For example, a material such as metal, resin, or cotton is woven into a screen shape as a screen. A non-woven fabric obtained by entangled fibers or fibers is used, and it is also effective to use a filter paper used for a filter for filtering fuel. These vaporization promoting members 19 are folded in a pleated shape as shown in FIG. 4, spiral-shaped as shown in FIG. 5, lattice-shaped as shown in FIG. As shown in FIG. 7, a tubular member or the like may be attached to the lower portion inside the gas-liquid separation chamber 5. The vapor-liquid separation chamber 5 is formed with an opening 21 for communicating with the introduction chamber 10 for the vaporized fuel, and a vaporization promoting member 19 as shown in FIG. A ventilation hole 22 is formed so as to traverse. This vent 22
It is preferable that the cross-sectional area is reduced as the distance from the opening 21 increases so that the atmosphere evenly spreads over the entire surface of the vaporization promoting member 19 at the time of purging.

The liquefaction promoting member 12 mounted on the upper part of the gas-liquid separation chamber 5 must be held from below so as not to drop. Therefore, if the liquefaction promoting member 12 is held by the upper end of the vaporization promoting member 19 mounted in the lower part of the gas-liquid separation chamber 5, the liquefaction promoting member 12 can be easily held. At that time, the liquefaction promoting member 12 is replaced by the vaporization promoting member 1.
If there is a risk of entering the inside of the plate 9, a perforated plate 23 may be arranged at the boundary between the two as shown in FIG.

In the fuel evaporative emission control apparatus having the above-described structure, the control valve V1 is opened when the pressure in the fuel tank 1 rises due to the evaporated fuel generated in the fuel tank 1 while the vehicle is stopped. The evaporated fuel in the tank enters the gas-liquid separation chamber 5 from the discharge port 17 through the vapor fuel pipe 2 and the valve V1. The liquid particles contained in the evaporated fuel are captured and separated by the liquefaction promoting member 12 in the upper part of the gas-liquid separation chamber 5, and the high boiling point component in the evaporated fuel is also cooled and liquefied, so that the gas-liquid separation is performed. Lower storage chamber 11 in chamber 5
It is stored inside. The liquid particles contained in the vaporized fuel and the high boiling point components in the vaporized fuel are removed in this way, and are adsorbed by the adsorbent 7 in the canister through the opening 21 through the vaporized fuel introduction chamber 10. It

When the purge valve V3 is opened at an appropriate time when the engine is operated, the negative pressure in the intake pipe 15 causes the atmospheric air to enter the canister from the atmospheric air port 13 and the adsorbent 7
The vaporized fuel adsorbed on the engine is desorbed (purged), and the vaporized fuel is entrained in the atmosphere to pass through the gas-liquid separation chamber 5, the purge valve V3 and the purge pipe 14 to the intake pipe 15 side of the engine. And is used for combustion in the engine.

While this atmosphere enters the gas-liquid separation chamber 5 through the opening 21 and passes through the vaporization promoting member 19, the vaporization promoting member 19
Causes the liquid fuel sucked from the storage chamber 11 to be vaporized by the capillary phenomenon. At that time, when the ventilation hole 22 formed in the vaporization promoting member 19 has a smaller cross-sectional area as it is farther from the opening 21, the air is averaged over the entire surface of the vaporization promoting member 19. Since it becomes widespread, vaporization is further promoted.

If the control valve V1 is opened when the purge valve V3 is opened, the evaporated fuel from the fuel tank 1 is discharged from the discharge port 17 of the control valve V1 and the purge valve V3. Since the inflow port 18 of the engine is close to the adsorbent 7 of the canister, the adsorbent 7 of the canister is not adsorbed, and the engine is operated through the control valve V1, the upper end in the gas-liquid separation chamber 5, the purge valve V3 and the purge pipe 14. It is supplied to the intake pipe 15 side, and the burden on the canister is reduced accordingly.

[0023]

The fuel evaporative emission control device of the present invention comprises:
A fibrous or strip-shaped liquefaction promoting member was attached to the upper part of the gas-liquid separation chamber, the lower part of the gas-liquid separation chamber was used as a storage chamber for the separated liquid fuel, and the gas-liquid separation chamber was communicated with the adsorbent storage chamber of the canister. Therefore, since the liquid particles contained in the vaporized fuel are captured and separated, the high boiling point component in the vaporized fuel is also cooled and liquefied and stored in the lower storage chamber in the gas-liquid separation chamber, The high boiling point component is not included in the evaporated fuel adsorbed on the adsorbent in the canister, so that it is extremely easy to desorb the evaporated fuel when purging the evaporated fuel, deterioration of the adsorbent is prevented, and the canister is downsized. can do.

Further, an upper part of the gas-liquid separation chamber is a liquefaction promoting chamber and a lower part is a storage chamber for the separated liquid fuel, and a vaporization promoting member made of a material for sucking the liquid fuel by a capillary phenomenon is mounted in the storage chamber. Since it is communicated with the adsorbent storage chamber of the canister, the liquid fuel sucked over a wide area from the storage chamber by the vaporization promotion member by capillary action while the atmosphere is passing through the vaporization promotion member in the gas-liquid separation chamber at the time of purging. Can be easily vaporized, and no heat energy or the like for vaporization is required.

If a fibrous or strip-shaped liquefaction promoting member is arranged in the liquefaction promoting chamber and the liquefaction promoting member is held by the upper end of the vaporization promoting member, the liquefaction promoting member can be held very easily.

Further, when a ventilation hole is formed in the vaporization promoting member, the atmosphere extends from the ventilation hole to the entire surface of the vaporization promoting member, and the cross-sectional area becomes smaller as the ventilation hole is farther from the opening. In this case, the air will spread all over the surface of the vaporization promoting member on average, so that the vaporization is further promoted.

Further, since the discharge port of the tank internal pressure control valve and the inflow port of the purge valve are provided close to each other at the upper end of the gas-liquid separation chamber, the control valve opens when the purge valve opens. If the fuel vapor from the fuel tank is not adsorbed by the adsorbent of the canister, the evaporated fuel from the fuel tank will pass through the control valve, the upper end of the gas-liquid separation chamber, the purge valve, and the purge pipe to the engine intake pipe side. Is directly supplied to the canister, and the burden on the canister can be reduced accordingly.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of a fuel evaporative emission control device according to the present invention.

FIG. 2 is a configuration diagram of a gas-liquid separation chamber of the fuel evaporative emission control device according to the present invention.

FIG. 3 is a table of experimental values of a liquefaction promoting member of the fuel evaporative emission control device according to the present invention.

FIG. 4 is a configuration diagram of an embodiment of a vaporization promoting member of the fuel evaporative emission control device according to the present invention.

FIG. 5 is a configuration diagram of another embodiment of the vaporization promoting member of the fuel evaporative emission control device according to the present invention.

FIG. 6 is a configuration diagram of still another embodiment of the vaporization promoting member of the fuel evaporative emission control device according to the present invention.

FIG. 7 is a configuration diagram of yet another embodiment of the vaporization promoting member of the fuel evaporative emission control device according to the present invention.

FIG. 8 is a configuration diagram of a main part of an embodiment of a vaporization promoting member of the fuel evaporative emission control device according to the present invention.

[Explanation of symbols]

 1 Fuel Tank 2 Fuel Evaporative Gas Passage 3 Canister Container 5 Gas-Liquid Separation Chamber 6 Adsorbent Storage Chamber 7 Adsorbent 10 Introducing Chamber 11 Liquid Fuel Storage Chamber 12 Liquefaction Promoting Member 14 Purging Pipe 15 Intake Pipe 17 Tank Internal Pressure Control Valve Discharge port 18 Inlet of purge valve 19 Vaporization promoting member 21 Opening 22 Vent hole V1 Tank internal pressure control valve V3 Page valve

Claims (7)

[Claims] 1. A canister having an adsorbent housed inside a container is provided in a fuel evaporative gas passage connecting a fuel tank side and an engine intake pipe side, and the evaporative fuel is supplied to the canister when the engine is stopped. Of the adsorbent to prevent desorption into the atmosphere by adsorbing the adsorbent to the adsorbent in the container and desorbing the fuel from the adsorbent by introducing the atmosphere into the container of the canister from the outside during engine operation. In the fuel evaporative emission control device for supplying and burning the gas to the intake pipe side, a gas-liquid separation chamber is formed in the container of the canister, and a fibrous or strip-shaped liquefaction promoting member is attached to the upper part of the gas-liquid separation chamber. Then, the fuel evaporative emission control device is characterized in that the lower portion of the gas-liquid separation chamber is used as a storage chamber for the separated liquid fuel, and the gas-liquid separation chamber is communicated with the adsorbent storage chamber of the canister. 2. A canister having an adsorbent contained in a container is provided in a fuel evaporative gas passage connecting between a fuel tank side and an engine intake pipe side, and the evaporative fuel is supplied to the canister when the engine is stopped. Of the adsorbent to prevent desorption into the atmosphere by adsorbing the adsorbent to the adsorbent in the container and desorbing the fuel from the adsorbent by introducing the atmosphere into the container of the canister from the outside during engine operation. In the fuel evaporative emission control device for supplying and burning the gas to the intake pipe side, a gas-liquid separation chamber is formed in the container of the canister, an upper part of the gas-liquid separation chamber is a liquefaction promoting chamber, and a lower part is a storage of separated liquid fuel. And a vaporization promoting member made of a material that sucks up liquid fuel by a capillary phenomenon is attached to the storage chamber, and the gas-liquid separation chamber is communicated with the adsorbent storage chamber of the canister. Evaporative emission suppressing device for. 3. The fuel evaporation according to claim 2, wherein a fibrous or strip liquefaction promoting member is arranged in the liquefaction promoting chamber, and the liquefaction promoting member is held by an upper end of the vaporization promoting member. Gas emission control device. 4. The fuel evaporative emission control device according to claim 2, wherein the vaporization promoting member is a filter paper member. 5. The fuel evaporative emission control device according to claim 2, wherein a vent hole is formed in an intermediate portion of the vaporization promoting member so as to traverse the vaporization promoting member. 6. The fuel evaporative emission control device according to claim 5, wherein the cross-sectional area of the vent hole traversing the vaporization promoting member is reduced as it is farther from the opening communicating with the canister. 7. A canister having an adsorbent contained in a container is provided in a fuel evaporative gas passage connecting a fuel tank side and an engine intake pipe side, and the evaporative fuel is supplied to the canister when the engine is stopped. Of the adsorbent to prevent desorption into the atmosphere by adsorbing the adsorbent to the adsorbent in the container and desorbing the fuel from the adsorbent by introducing the atmosphere into the container of the canister from the outside during engine operation. In the fuel evaporative emission control device for supplying and burning the gas to the intake pipe side, a gas-liquid separation chamber is formed in the container of the canister, an upper part of the gas-liquid separation chamber is a liquefaction promoting chamber, and a lower part is a storage of separated liquid fuel. And a discharge port of the tank internal pressure control valve and an inlet of the purge valve are provided close to each other at the upper end of the gas-liquid separation chamber, and the gas-liquid separation chamber is communicated with the adsorbent storage chamber of the canister. Evaporative emission suppressing device according to claim and.