JPS63154850A - Vaporized fuel disposing device for vehicle - Google Patents

Abstract

PURPOSE:To improve collection efficiency, by a method wherein on adsorbent, having a high pore size, and an absorbent, having a low pore size, and activated cola fiber are arranged in a direction extending from the one end of a canister container, in which a vaporized fuel introduction and a purge port are formed, toward the other end in which an open air release port is formed. CONSTITUTION:A vaporized fuel introduction port 23, a feed oil vaporized fuel introduction port 24, and a purge port 25, connected to the suction pipe of an internal combustion engine are formed in an upper end plate 22 of a canister container 20, and an open air release port 32 opened to the open air is formed in the other end of the canister container 20. A first adsorption layer 33, formed in the direction of the open air release port 32 side by laminating granular activated cool having a high pore size of approximate 15 A, a second adsorption layer 34, formed in the middle by laminating granular activated coal adsorbing mainly a low boiling point component and having a low pore size of approximate 10A, end a third adsorbent layer 35, formed by activated coal fiber, ore formed, in order, from the upper end plate 22 side toward the open air release port 32 side.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a processing device, that is, a canister, that prevents evaporated fuel generated in a fuel tank of a vehicle from being directly released into the atmosphere, and particularly relates to a canister. The present invention relates to a canister that can effectively absorb evaporated fuel generated in a fuel tank.

[Conventional technology]

It is known that canisters are used in vehicles to prevent the evaporated fuel generated in the fuel tank from being directly released into the vehicle.

Regarding the structure of the canister, an example is given in JP-A-57-1.
It is described in Publication No. 76341. The second method is to provide, at one end of the canister container, an evaporated fuel inlet that communicates with the fuel tank and guides the evaporated fuel generated in the fuel tank, and a persilo that communicates with the intake passage of the internal combustion engine, and -1- The other end of the canister container is provided with an air opening that communicates with the atmosphere, and an adsorption layer made of granular activated carbon is provided within the canister container.

This type of canister is used to store evaporated fuel generated in the fuel tank due to the influence of ambient temperature when the engine is stopped, and evaporated fuel generated in the fuel tank by heating with fuel returned from the engine while the engine is running (hereinafter referred to as these). The evaporated fuel (usually referred to as evaporated fuel) is introduced into the canister container from the evaporated fuel inlet and is adsorbed by an adsorption layer made of granular activated carbon contained in the canister container. Then, the air component from which the fuel component has been separated is released from the atmosphere opening.

On the other hand, when the engine is running, the air in the canister container is sucked into the intake passage by the negative pressure generated in the intake passage of the engine, and at this time, new air is introduced from the atmosphere opening and the granular activated carbon is absorbed by the air. The adsorbed fuel components are separated from the granular activated carbon and drawn into the intake passage. This activates the granular activated carbon, that is, restores its adsorption capacity.

[Problem that the invention seeks to solve]

By the way, the above-mentioned conventional canister mainly stores fuel that evaporates in the fuel tank while the engine is stopped and when the engine is running.
In other words, consideration has been given to collecting evaporated fuel to prevent it from being released into the atmosphere.

However, in recent years, air pollution caused by evaporated fuel (hereinafter referred to as evaporated fuel during refueling) generated even when refueling at a gas station or the like has become a problem.

For this reason, it has become necessary to also process the evaporated fuel during refueling, but installing a new canister exclusively for processing only the evaporated fuel during refueling is disadvantageous in terms of vehicle mounting space and cost. In particular, since the amount of evaporated fuel during refueling is almost proportional to the injection speed of fuel supplied from the refueling nozzle, a large amount of evaporated fuel is generated in a short period of time, and the canister to handle this becomes large. Therefore, it is disadvantageous to install it in a vehicle.

For this reason, it is conceivable that the conventional canister that normally collects evaporated fuel may also be used as a canister that processes evaporated fuel during refueling.

However, conventional canisters that collect evaporated fuel typically use a single adsorbent. That is, the fuel components that evaporate in the fuel tank while the engine is stopped or running range from low boiling point components to high boiling point components, and an adsorbent that can uniformly adsorb all of these components is used.

On the other hand, since the evaporated fuel generated during refueling is mainly composed of low boiling point components and flows in at high speed, the conventional adsorbents mentioned above cannot completely capture the low boiling point components of the evaporated fuel generated during refueling. At the same time, there is a problem that the gas blows through and is released into the atmosphere.

The present invention aims to provide a dual-purpose vehicular evaporative fuel processing device that can efficiently collect normal evaporated fuel and also effectively collect evaporated fuel during refueling with a single canister. It is something to do.

[Means for solving problems]

In the present invention, one end of the canister container is provided with an evaporative fuel inlet communicating with the fuel tank and introducing the evaporative fuel generated in the fuel tank, and an evaporative fuel inlet communicating with the fuel tank and introducing the evaporative fuel generated when refueling the fuel tank. A refueling evaporated fuel inlet that leads to the refueling and a persillo that communicates with the intake passage of the internal combustion engine are provided, and an open port that communicates with the atmosphere is provided at the other end of the canister container, and the adsorbent to be filled in this canister container is provided. It has a three-layer structure, with a first adsorption layer on the upstream side consisting of an adsorbent with a large pore diameter that mainly adsorbs high-boiling components, and a second adsorption layer in the middle consisting of an adsorbent with a small pore diameter that mainly adsorbs low-boiling components. It is characterized in that a third adsorption layer made of activated carbon fibers with a high adsorption rate is provided on the layer and the atmosphere side.

[Effect]

According to the configuration of the present invention, when the normal vaporized fuel is introduced into the canister container from the vaporized fuel inlet, the high boiling point components contained in the normal vaporized fuel are mainly absorbed into the first adsorption layer made of the adsorbent with a large pore size. It is selectively adsorbed, and the low-boiling components are mainly adsorbed on the downstream side of the second adsorption layer, which is made of an adsorbent with a small pore size. In this case, the rate at which the evaporated fuel normally flows into the canister is extremely low, so that no blow-through to the atmosphere occurs. On the other hand, when refueling vaporized fuel is introduced into the canister container through the refueling vaporized fuel inlet,
The low boiling point components mainly contained in the evaporated fuel during refueling are adsorbed on the second adsorption layer made of an adsorbent with a small pore diameter. In this case, the flow rate of the evaporated fuel into the canister container during refueling is quite fast, so the evaporated fuel that cannot be completely adsorbed by the first and second adsorption layers is transferred to the third layer made of activated carbon fibers, which has a high adsorption rate. It is adsorbed by the adsorption layer and therefore does not blow through to the atmosphere. When the engine is running, the air in the canister container is sucked into the intake passage from the versilor by the negative pressure generated in the intake passage of the engine, and at this time, new air is introduced from the atmosphere opening and the air is used to The fuel components adsorbed on the adsorption layer are separated and drawn into the intake passage.

This activates each adsorption layer.

〔Example〕

The present invention will be described below based on an embodiment shown in the drawings.

FIG. 1 is a sectional view of the entire canister, and FIG. 2 is a schematic diagram of a fuel vapor treatment system using this canister. First, the fuel vapor treatment system shown in FIG. 2 will be explained.

In the figure, 1 is a fuel tank, 2 is a canister, and 3 is an engine.

The fuel tank 1 includes a fuel filler port 4, and a fuel nozzle 5 is inserted into the filler port 4 to supply fuel. The fuel tank 1 is connected with a normal evaporated fuel conduit 6 that guides the normal evaporated fuel generated in the fuel tank 1 to the canister 2, and a refueling evaporated fuel conduit 7 that guides the evaporated fuel during refueling to the canister 2. It is connected. The evaporated fuel conduit 7 during refueling is provided with a valve 8 which is normally closed but automatically opens when the refueling nozzle 5 is inserted into the refueling port 4 upon detecting this.

Further, a purge conduit IO is connected between the canister 2 and the intake passage 9 of the engine 3.

Details of the canister 2 will be explained based on FIG. 1. 20 is a canister container, and this canister container 20 is constructed by airtightly closing the upper end opening of a container body 21 with an upper end plate 22.

The upper end plate 22 is formed with a normal evaporated fuel inlet 23 connected to the normal evaporated fuel conduit 6, and a refueled evaporated fuel inlet 24 connected to the evaporated fuel conduit 7 during refueling. A versilor 25 is provided which is connected to the purge conduit 10.

Normally, a valve chamber 2B is formed below the vaporized fuel inlet 23, and a negative pressure check valve 27 is provided in this valve chamber 26. Further, this valve chamber 2B communicates with a guide vibe 28 formed in the center of the end plate 22 of the section A, and this guide vibe 28 is provided with a positive pressure check valve 29.

Another valve chamber 30 is formed in the lower part of the vershilo 25, and this valve chamber 30 has another negative pressure check valve 3.
1 is provided.

Further, an air opening 32 is formed at the other end of the container body 2I.

A fuel adsorbent is accommodated in such a canister container 20. The fuel adsorbent has a three-layer structure, and from the upper end plate 22 side to the atmosphere opening 32 side, an adsorbent with a large pore size (about 15 layers) that mainly adsorbs high boiling point components, such as granular activated carbon, is placed. First adsorption layer 3 formed by stacking
3, and a second adsorption layer 34 consisting of a layered intermediate adsorbent with a small pore diameter (about 10 particles) that mainly adsorbs low-boiling components, such as granular activated carbon, and activated carbon fibers with a high adsorption rate. The third adsorption layer 35 is composed of:

Filters 3B, 37, 38 are provided between the adsorption layer 33 of each layer 1, the second adsorption layer 34, and the third adsorption layer 35 so that the adsorbents of these layers do not mix. ing.

The first adsorption layer 33 occupies approximately 65% of the internal volume of the canister container 20, the second adsorption layer 34 also occupies approximately 3096, and the third adsorption layer 35 occupies approximately 5%. , these filling capacities are set based on actually measured proportions.

Further, the refueling evaporated fuel inlet is opened in a space 39 formed between the upper end plate 22 and the upper filter 3B.

A baffle 40 is installed in the first adsorption layer 38, facing the guide vibe 2B, with its legs 41 fixed to the container body 21.

The operation of the embodiment with such a configuration will be explained.

The evaporated fuel generated in the fuel tank 1 due to the influence of ambient temperature while the engine is stopped and the fuel returned from the engine while the engine is running are added to the evaporated fuel (usually evaporated fuel) that is generated in the fuel tank 1. , is normally introduced into the canister container 20 from the evaporated fuel conduit 6 and the evaporated fuel inlet 23. The normal evaporated fuel that entered the canister container 20 from the evaporated fuel inlet 23 flows into the valve chamber 2B.
The liquid flows from the gas into the guide pipe 28, pushes open the positive pressure check valve 29 of the guide pipe 28, and is guided to the first adsorption layer 33.

In case 2, a baffle 40 is provided directly below the guide pipe 28.
Because of the arrangement, the normal evaporated fuel that has flowed into the first adsorption layer 33 from the guide pipe 28 is diffused into the surrounding area as shown by the arrow, and flows through the first adsorption layer 33 in a dispersed manner.

Since evaporated fuel normally contains not only low-boiling point components but also a considerable amount of high-boiling point components, the high-boiling point components are mainly selectively adsorbed by the first adsorption layer 33 made of adsorbent with a large pore size, and the low-boiling point components is mainly adsorbed on the downstream side of the second adsorption layer 34 made of an adsorbent with a small pore diameter.

In this case, since the flow rate of the vaporized fuel into the canister container 20 is usually extremely slow, if a predetermined adsorption capacity is given to the first adsorption layer 33 and the second adsorption layer 34,
It does not blow through to the atmosphere through the atmosphere opening 32.

Therefore, the air component separated from the fuel component is released from the atmosphere opening port 32, so that no air pollution occurs.

On the other hand, when refueling, when the refueling nozzle 5 is inserted into the refueling port 4, this is detected and the valve 8 is automatically opened. Therefore, the refueling evaporative fuel inlet 6 is opened, and the inside of the fuel tank I and the refueling evaporative fuel inlet 6 communicate with each other.

Therefore, evaporated fuel generated in the fuel tank 1 during refueling is guided into the canister container 20. Since the fuel that evaporates during refueling evaporates at room temperature, it is mainly a low boiling point component.

The refueling vaporized fuel introduced into the canister container 20 from the refueling vaporized fuel inlet 6 first passes through the first adsorption layer 33, but since the first adsorption layer 33 has a high affinity with high boiling point components, it has already been absorbed. It is adsorbed as a second adsorption film on the adsorption film of the high boiling point component that has been adsorbed.

Most of the low boiling point components that have not been completely adsorbed by the first adsorption layer 33 are adsorbed by the second adsorption layer 34.

In this case, the canister container 20 for vaporized fuel during refueling
Since the inflow speed into the interior is quite fast, the above-mentioned first and second
The evaporated fuel that cannot be completely absorbed by the adsorption layers 33 and 34 is adsorbed by the third adsorption layer 35 made of activated carbon fibers having a high adsorption rate, so that the evaporated fuel does not blow into the atmosphere.

When the engine is operating, the negative pressure generated in the intake passage 9 of the engine 3 acts on the persillo 25 from the purge conduit 10. This negative pressure opens the negative pressure check valve 31 of another valve chamber 30 provided at the lower part of the Persillo 25 and sucks the air inside the canister container 20 into the intake passage 9. For this reason, new air is introduced from the atmosphere opening lower, and this air is guided to the Persillo 25 through the third adsorption layer 35, the second adsorption layer 34, and the first adsorption layer 33. This air is adsorbed 1 Akane 3
5.34.33, the already adsorbed fuel components are separated from each adsorption layer 35.34.33 and drawn into the intake passage 9. This allows each adsorption layer 35.34.
33 activations are made.

Therefore, according to the above embodiment, a single canister 2
By this, the normal evaporated fuel and the evaporated fuel during refueling can be adsorbed and processed, so there is no need to install a special canister in the vehicle that processes only the evaporated fuel during refueling.

Moreover, the fuel adsorption agent mainly consists of a first adsorption layer 33 with a large pore diameter that adsorbs high boiling point components, a second adsorption layer 34 with a small pore diameter that adsorbs low boiling point components, and activated carbon fibers that have a fast success/failure rate. Since it has a three-layer structure with the third adsorption layer 35, even if most of the components of the vaporized fuel at the time of refueling are low boiling point components, blow-through does not occur and air pollution is reliably prevented by +1. I can do it.

In the above embodiment, an evaporative fuel processing system exclusively for EFI was explained, but in the case of a cab car, it is necessary to process evaporative fuel from the carburetor, so the evaporative fuel from the carburetor is placed in the canister container 20 shown in FIG. You may also introduce it.

〔Effect of the invention〕

As explained above-1-, according to the present invention, a first adsorption layer with a large pore size that adsorbs a high boiling point component, a second adsorption layer with a small pore size that adsorbs a low boiling point component, and a high adsorption rate. Since it has a three-layer structure with the third adsorption layer made of activated carbon fibers, normal evaporated fuel can be efficiently collected, and evaporated fuel during refueling can also be effectively collected. Therefore, the normal evaporated fuel and the evaporated fuel during refueling can be adsorbed and processed by a single canister, and there is no need to install a special canister in the vehicle that processes only the evaporated fuel during refueling.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a sectional view of a canister, and FIG. 2 is a schematic configuration diagram of an evaporative fuel processing system using this canister. ■...Fuel tank, 2...Canister, 3...Engine, 4...Refueling port, 5...Refueling nozzle, 6...
・Normal evaporative fuel conduit, 7... Refueling evaporative fuel inlet 8.
... Valve, IO... Purge conduit, 20... Canister container, 23... Normal vaporized fuel inlet, 24... Refueling vaporized fuel inlet, 25... Persil, 27... Negative pressure Check valve, 29... Positive pressure check valve, 31... Other negative pressure check valve,
32... Atmosphere opening port, 33... First adsorption layer, 34
...Second adsorption layer, 35...Third adsorption RId, 3B
, 37.38...filter.

Claims (1)

[Claims] At one end of the canister container, an evaporative fuel inlet communicating with the fuel tank and guiding the evaporative fuel generated in the fuel tank, and a refueling evaporative fuel communicating with the fuel tank and guiding the evaporative fuel generated during refueling into the fuel tank. In addition to providing an inlet and a purge port that communicates with the intake passage of the internal combustion engine,
An atmosphere opening port communicating with the atmosphere is provided at the other end of the canister container, and a first adsorbent made of an adsorbent having a large pore size is disposed inside the canister container from the one end to the other end. 1. An evaporative fuel processing device for a vehicle, comprising an adsorption layer, a second adsorption layer made of an adsorbent with a small pore diameter, and a third adsorption layer made of activated carbon fiber.