JPH01159455A - Evaporative fuel treating equipment for vehicle - Google Patents

Abstract

PURPOSE:To abate a speed element in an adsorptive direction by means of adsorbent for the evaporative fuel as well as to improve an adsorptive or desorptive efficiency in the evaporative fuel by forming a diffusion chamber in an inlet port opening of a casing filled up with the said evaporative fuel adsorbent. CONSTITUTION:Filters 5, 7 composed of a nonwoven fabric or the like each and keep plates 6, 8 with interconnecting holes 6a, 8a are fixed each to each inner circumferential surface of both upper and lower parts in the inner part of a casing 1, an adsorbent 3 consisting of activated carbon or the like is filled up in a space between both these filters 5, 7, forming an adsorbent layer 4. In the inner part of the casing 1, a first space part 9 is formed in an upper part of the adsorbent layer 4 and a second space part 10 in the lower part, respectively. In addition, the adsorbent layer 4 and the second space part 10 are divided into two parts by a partition plate 11, and an atmospheric port 2 is opened to a space 10b, while an inlet pipe 12 and a purge pipe 13 are interconnected to a space 10a after piercing through the space part 9 and a first adsorbent layer 4a.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention adsorbs evaporated fuel from a fuel storage chamber such as a fuel tank of a vehicle to prevent the evaporated fuel from being released into the atmosphere. The present invention relates to an evaporative fuel processing device (hereinafter referred to as a canister).

[Conventional technology]

Conventionally, as this type of canister, for example,
As shown in Publication No. 162214, fuel evaporated from a vehicle fuel tank is introduced to the upper surface of an adsorbent layer in the canister through a pipe, and the evaporated fuel is adsorbed by this adsorbent layer. It has become.

Conventional canisters as described above generally have adsorption characteristics as shown in FIG. 12. Figure 12 shows the height of the canister, and when the diameter of the canister is D, L/
FIG. 3 is a diagram that the inventors of the present invention found through experimental studies to determine the relationship between D and the adsorption amount of evaporated fuel. As can be seen from this figure, if the height and diameter of the canister are set so that L/D>1, a canister with good adsorption/desorption efficiency can be realized.

However, although this setting applies to cases where the flow rate into the canister is slow, such as evaporated fuel from fuel stored in a fuel tank or fuel evaporated in a float chamber provided in a vehicle's carburetor, For example, when a large amount of steam is generated and the inflow speed is fast, such as when refueling with gasoline, simply increasing L/D is not enough.
As shown in Figure 3, the adsorption/desorption efficiency does not improve much. 1st
Figure 3 shows that the inflow velocity into the canister is 30 to 40 f/mi.
FIG. 3 is a diagram obtained through experimental study of the relationship between L/D and the adsorption amount of evaporated fuel in the case of n. Therefore, in order to obtain sufficient adsorption and desorption efficiency even when the generated steam is large and the flow velocity is high, the canister must be made larger, which makes it difficult to mount it on a vehicle. There's a problem.

The present invention was made in view of the above problems.
It is an object of the present invention to provide a compact canister that can obtain sufficient adsorption/desorption efficiency even when a large amount of generated steam is generated and the inflow speed is high.

[Means for solving problems]

In order to solve the above problems, the present invention takes the following technical measures.

That is, a casing having an introduction port for introducing evaporated fuel from a fuel tank, a evaporated fuel adsorbent disposed within the casing that adsorbs evaporated fuel introduced from the introduction port, and the introduction port of the casing. The present invention is characterized by comprising a diffusion chamber formed at the opening and configured to diffuse the evaporated fuel introduced from the introduction port and reduce the velocity component of the evaporated fuel in the adsorption direction by the evaporated fuel adsorbent.

〔Example〕

The present invention will be described in detail below based on the drawings.

In FIG. 1, a casing 1 made of resin has a cylindrical shape, and an atmospheric port 2 that is open to the atmosphere is formed on its bottom surface 1a.

The inside of the casing l is filled with an adsorbent 3 made of, for example, activated carbon, and this adsorbent 3 forms an adsorbent layer 4.
is formed. A filter 5 made of nonwoven fabric or the like is disposed on the lower surface of the adsorbent layer 4 in the figure, and a lower press plate 6 having communication holes 6a is further disposed on the lower surface thereof. Further, a filter 7 made of nonwoven fabric or the like is arranged on the upper surface of the adsorbent N4 in the figure, and an upper presser plate 8 having communication holes 8a is further arranged on the upper surface. Note that the filter 5, lower press plate 6, filter 7, and upper press plate 8 are fixed to the inner peripheral surface of the casing 1, so that their positions are fixed.

Inside the casing 1, a first space 9 is formed above the adsorbent layer 4, and a second space 10 is formed below the adsorbent layer 4.

A partition plate 11 is provided inside the casing 1,
This partition plate 11 allows the adsorbent N4 to be transferred to the A layer 4aSBii4.
It is divided into two layers: b. The second space 10 is also divided into two spaces 10a and 10b by the partition plate 11, and the atmospheric port 2 communicates with the space 10b. Note that the first space 9 is not divided by the partition plate 11, and the entire space is in communication.

An introduction pipe 12 and a purge pipe 13 are inserted into the inside of the casing 1 from the upper exterior.
The purge pipe 13 passes through the first space 9 and the first adsorbent JW4a and communicates with the space 10a of the second space 10, respectively. Note that the introduction pipe 12 and the purge pipe 13 are welded and fixed to the casing 1 so that the fluid in the first space 9 does not leak.

The canister 1 (10) of this embodiment having the above configuration is as follows:
They are connected and mounted on a vehicle as shown in FIG. Second
In the figure, the introduction pipe 12 of the canister 1 (10) communicates with the vicinity of the introduction port 20a of the fuel tank 20 via a switching valve 21 and a tank hose 22. The switching valve 21 is a valve that is opened for a predetermined time only when refueling, and
and canister 1 (10).

The purge pipe 13 of the canister 1 (10) is connected to an intake pipe of an engine (not shown) via a communication hose 23 and a purge control valve 24. The purge control valve 24 is a valve for adjusting the amount of evaporated fuel released from the canister 1 (10) introduced into the intake pipe.

In this embodiment, the canister 1 (10) is used as an on-board canister for adsorbing only the evaporated fuel generated when refueling the fuel tank.
The evaporated fuel from the fuel stored in the 0 is adsorbed by a conventionally known evaporative emission canister 25. The canister 25 is connected to the fuel tank 20 via a tank hose 26, and is connected to an intake pipe (not shown) via a connecting case 27.

Next, the operation of this embodiment will be explained.

The amount of fuel supplied to the inlet 20a of the fuel tank 20 is approximately 3
It flows into the fuel tank 20 at a flow rate of 0 to 40!2/min. At this time, the fuel inlet 20a is sealed, the switching valve 21 is open, and the evaporated fuel generated in the fuel tank 20 flows into the inlet pipe 12 via the tank hose 22. The vaporized fuel that has flowed into the casing 1 through the introduction pipe 12 is discharged from the opening bridge 12a of the introduction pipe 12 into the space 10a of the second space 10. This discharged evaporated fuel is transferred to the bottom surface 1a of the casing 1, which acts as a deflection plate.
The liquid collides with the inner wall of the space 10a and spreads evenly within the space 10a, reducing the flow velocity. Note that the distance from the open end 12a of the introduction pipe 12 to the inner wall of the bottom surface 1a is set to about 6 cm.

Thereafter, the evaporated fuel flows from below to above the A layer 4a of the adsorbent M4 through the communication hole 6a of the upper holding plate 6 and the refilter 5, and the adsorption phenomenon gradually progresses.

Here, the evaporated fuel collides with the inner wall of the bottom surface 1a and the space 10
Since the vaporized fuel flows through the A layer 4a of the adsorbent layer 4 after being diffused in the adsorbent layer A, the vaporized fuel may not be sufficiently adsorbed and pass through, unlike when vaporized fuel with a high flow rate flows directly through the adsorbent layer. Therefore, the evaporated fuel is adsorbed in the entire area of the A layer 4a of the adsorbent layer 4, and the utilization efficiency of the adsorbent layer 4 becomes extremely high.

Next, the evaporated fuel leaked from the A layer 4a of the adsorbent N4 is
After being discharged into the first space 9 and being diffused, the adsorbent layer 4
It flows from above to below the eight layers 4b and is adsorbed. In this case as well, the evaporated fuel is once diffused into the adsorbent layer 4.
Since the adsorbent passes through eight layers 4b, the utilization efficiency of the adsorbent layer 4 becomes high.

Further, when the engine is operating, negative pressure is generated in the intake air (not shown), and this negative pressure is introduced into the canister 1 (10) through the purge hose and purge pipe 13. Due to this negative pressure, the atmosphere is introduced into the canister 1 (10) from the atmosphere port 2, and the air is introduced into the canister 1 (10) through the space iob of the second space 10, the BJii 4b of the adsorbent layer 4, the first space 9, and the A of the adsorbent layer 4. layer 4a
, and sequentially pass through the space 10a of the second space section 10. This atmosphere causes the vaporized fuel adsorbed on the adsorbent layer 4 to be desorbed and flows into the purge pipe 13 . The evaporated fuel that has flowed into the purge pipe 13 passes through the purge hose 23, its flow rate is adjusted by the purge control pulp 24, and is sucked into an intake pipe (not shown).

Next, the canister 1 (10) of this embodiment will be described based on experiments and studies conducted by the inventors. FIG. 3 and FIG. 4 each show a sample canister that was used as a comparison control for this example.

The canister (sample 1) shown in FIG. 3 has an adsorbent layer 4 disposed inside a cylindrical casing 1 so as to form spaces 9 and 10 at both ends, and an introduction port on the top surface of the casing 1. This is a conventionally known type in which an atmospheric port 1a is formed on the lower surface of the purge port IC1. Note that the ratio L/D of the height L and diameter of this canister 30 is 1.8.
The capacity of the adsorbent layer 4 is 41.

The canister (sample 2) shown in FIG. 4 is an improved type of canister shown in FIG.
1 into two layers 4a and 4b.

Note that the capacity of this adsorbent N4 is 3.52.

Moreover, the capacity of the adsorbent layer 4 of the canister 1 (10) of this embodiment shown in FIG. 1 is 3.51! , and the material of the canister shown in FIGS. 3 and 4 and the adsorbent used therein are the same as this canister 1 (10).

Next, the experimental method will be explained using FIG. 5.

In FIG. 5, gasoline stored in a fuel reservoir 40 is first sucked up by an air motor 41, and the fuel flows into the fuel tank 20 at a flow rate of 30 to 38 I! ,/min. This fuel tank 20 is connected to the sample via a switching valve 21 that is turned on only when fuel is introduced.
The weight of the adsorbent after fuel is introduced and breakthrough adsorption is measured, and the value obtained by subtracting the weight after purging at a predetermined air flow rate from the weight, that is, the adsorption/desorption capacity is evaluated.

The experimental results are shown in FIG. As is clear from FIG. 6, the adsorption/desorption capacity per activated carbon 11 of this example is much larger than that of Samples 1 and 2, which indicates that the utilization efficiency of the adsorbent layer 4 is high. It shows.

In addition, in the course of this experiment, in the canister of sample 1, the vaporized fuel introduced from the introduction port 1b was adsorbed by the adsorbent layer 4 at an uneven advancing speed, as shown in FIG. The result was that the speed was fast and the inner circumferential side was slow. This is considered to be due to the fact that the amount of vaporized fuel introduced from the introduction port 1b is large and its inflow speed is high.

On the other hand, in the canister 1 (10) of this embodiment, the evaporated fuel introduced from the introduction vibrator collides with the inner wall of the bottom surface 1a and is diffused into the space 10a of the first space 10, and then forms an adsorbent layer. 4, the adsorption progresses almost uniformly throughout as shown in FIG. Therefore, the adsorption efficiency of the adsorbent layer 4 is increased.

As described above, according to this embodiment, sufficient adsorption efficiency can be obtained without increasing the size of the fuel even if the vaporized fuel is large and has a high inflow rate.

Note that the present invention is not limited to the above embodiments,
Various modifications are possible without departing from the gist of the invention. below,
A modification thereof will be explained using FIGS. 9 to 11.

In the embodiment shown in FIG. 9, the adsorbent N4 is
lb has a three-layer structure, which further increases the adsorption efficiency.

In the embodiment shown in FIG. 10, the adsorbent layer 4 is the inner layer 4a.
and the outer layer 4b, and the introduction pipe 12 and the purge vibe 13 penetrate the inner layer 4a and the first layer 4b.
The vaporized fuel introduced through the introduction pipe 12 enters the space 10a of the space 10.
After colliding with the bottom surface 30a of the inner case 30 forming the inner case 30 and diffusing within the space 10a, the particles are successively attracted by the inner layer 4a and the outer layer 4b.

In the embodiment shown in FIG. 11, the adsorbent N4 is applied to the inner layer 4a.
and the outer layer 4b, and the atmospheric vibration 3
1 penetrates the layer 4a on the inner peripheral side and enters the space 9 of the second space 9
The evaporative fuel introduced through the introduction bow 12 collides with the upper surface 30a of the inner case 30 forming the space 9b and diffuses within the space 9, and then flows to the outer circumferential side. layer 4b, and layer 4a on the inner circumferential side in order.

Next, still another embodiment of the present invention will be described using FIG. 14.

In FIG. 14, the canister 2 (10) is a cylindrical outer casing 20 made of resin or iron plate.
2, and a cylindrical inner casing 203 disposed inside the outer casing 202 and formed of resin or iron plate.

Inside the outer casing 202 and the inner casing 203
The outer periphery of the adsorbent layer 20 is filled with an adsorbent 206 made of, for example, activated carbon.
5 is formed. A filter 220 made of non-woven fabric or the like is disposed on the lower surface of this adsorbent 205 in the figure, and an inner casing 203 having a communication hole 230a is disposed on the lower surface of the filter 220.
A bottom surface portion 230 is arranged. In addition, the adsorbent layer 205
In the figure, a filter 217 made of non-woven fabric or the like is also disposed on the upper surface, and an upper holding plate 214 having a communication hole 214a is further disposed on the upper surface. Note that the filter 220,
Bottom part 230 of inner casing 203, filter 217
The upper press plate 214 is fixed to the inner peripheral surface of the outer casing 202, thereby fixing its position.

Also, an adsorbent 204 made of an adsorbent 206 is formed inside the inner casing 203, and this adsorbent N2O
4, there is a filter 219 and a communication hole 216 on the bottom surface.
An upper presser plate 216 having a
04, the filter 218 and the communication hole 21 are located at the upper part of the figure.
An upper presser temporary 215 having a diameter of 5a is arranged. Note that a communication hole 215a is provided at a position facing the second introduction port 245.
is not formed. Also, inside the inner casing 203, a first space 2 is located below the adsorbent N2O4 in the figure.
07 is formed. Note that inside the outer casing 202, a second space 208 is formed above the adsorbent layer 5, and a third space 209 is formed below the adsorbent layer 205.

A first introduction pipe 210 is provided on the upper surface of the outer casing 202 in the figure.
, a second introduction port 245 and a purge pipe 211 are formed. One end 210a of the first introduction pipe 210 communicates with the fuel supply pipe 20a of the fuel tank 20 via piping 231, and the other end 210b penetrates the second space 208 and the adsorbent layer 204 and connects to the first space 207. It's communicating. The second introduction port 245 is formed to communicate with the second space 208, and one end 245a is connected to the fuel tank 2 through the piping 243.
It communicates with a port 22 formed on the top surface of 0. One end 211a of the purge pipe 211 penetrates the second space 208 and the adsorbent layer 204 and communicates with the first space 207, and the other end 211b connects to the opening port of the throttle valve 242 of the intake pipe 241 via piping 232. It is connected to 240.

Further, a control valve 244 that opens when the pressure of evaporated fuel from the fuel tank 20 exceeds a predetermined pressure is provided in the piping 243, and a control valve 244 is provided in the piping 232 to control the flow rate of the evaporated fuel sucked into the intake pipe 240. A control valve 235 is provided.

An atmospheric port 213 is formed on the lower surface of the outer casing 202 in the figure, and this atmospheric port 213 is open to the atmosphere.

Next, the operation of this embodiment will be explained.

When the evaporated fuel generated from the fuel stored in the fuel tank 20 reaches the opening pressure of the control valve 244 or higher during engine operation and stop, it passes through the piping 243 and the second introduction port 245 to the canister 2 (10). be introduced within.

The evaporated fuel introduced through the second introduction port 245 is
It collides with the holeless part of the upper press plate 215 and the second space part 20
After being diffused in step 8, it is adsorbed in adsorbent layers 204 and 205.

On the other hand, when refueling, the fuel supply pipe 20 of the fuel tank 20
The fuel supplied to a is about 30-40! The fuel flows into the fuel tank 20 at a flow rate of /min. At this time, the switching valve 21 is open, and the evaporated fuel generated during refueling is transferred to the pipe 231,
It is introduced into the canister 2 (10) through the first introduction pipe 210.

The evaporated fuel introduced through the first introduction pipe 210 is
It is discharged from the open end 210b of the introduction pipe 210 into the first space 207. The discharged evaporated fuel collides with the inner wall of the bottom surface 230 of the inner casing 203, which acts as a deflection plate, and is uniformly diffused within the space 207, reducing the flow velocity.

Note that from the open end 210b of the first introduction pipe 210 to the bottom part 2
The distance to the inner wall of No. 30 is set to about 5 mm.

Thereafter, the evaporated fuel flows from the bottom to the top of the adsorbent layer 204 through the communication hole 216a of the upper holding plate 216 via the filter 219, and the adsorption phenomenon gradually progresses.

Here, the evaporated fuel collides with the inner wall of the bottom part 230 and the first
Since the vaporized fuel flows through the adsorbent layer 204 after being diffused in the space 207, the vaporized fuel does not pass through without being sufficiently adsorbed, unlike when vaporized fuel with a high flow rate flows directly through the adsorbent layer. The evaporated fuel is adsorbed in the entire area of the adsorbent cloth layer 204, and the utilization efficiency of the adsorbent layer 204 is extremely high.

Next, the vaporized fuel leaking from the adsorbent N2O4 is discharged into the second space 208 and diffused, and then flows from above to below the adsorbent layer 5 and is adsorbed. Also in this case, the evaporated fuel is diffused within the space 208 and then passes through the adsorbent layer 205, so that the utilization efficiency of the adsorbent 205 is increased.

Further, when the engine is operating, the control valve 235 opens depending on the operating state of the vehicle. Therefore, the negative pressure generated in the intake pipe 240 is introduced into the canister 2 (10) through the piping 232 and the purge pipe 211, and thereby the atmosphere is introduced into the atmospheric port 213. This air passes through the third space 209, the adsorbent layer 205, the second space 208, the adsorbent layer 204, and the third space 207 in order, and the evaporated fuel mainly adsorbed on the adsorbent layer 204 is transferred to the purge pipe. 2
11 and into the intake pipe 240.

According to the above embodiment, evaporative fuel is generated during refueling in large quantities (1 (10) g/min) in a short period of time and occurs infrequently, and vaporized fuel is generated gradually over a predetermined period (2 g/min).
One canister can adsorb both evaporated fuel from stored fuel, which occurs relatively frequently (0 to 25 g/h).

Moreover, in this embodiment, by introducing the evaporated fuel during refueling into the first space 207 through the first introduction pipe 210, the evaporated fuel is mainly adsorbed by the adsorbent layer 204, and the evaporated fuel is absorbed from the stored fuel. The vaporized fuel is transferred to the second introduction port 24.
5 into the second space 208, the evaporated fuel is adsorbed by both the adsorbent layers 204 and 205. Therefore, when both evaporated fuels are introduced from the first introduction pipe 210, In comparison, the adsorbent layer 204.20
5 can be made uniform.

FIG. 15 shows the adsorption rate of vaporized fuel after adsorption of the adsorbent layer 204 of this example, which was determined by experiment. The left side of the adsorbent N2O4 in FIG. The right side shows the atmospheric port 213 (upper side in FIG. 14). Note that the comparative example shows a case where both evaporated fuels are introduced from the first introduction pipe 210. 1st
As is clear from FIG. 5, according to this example, the adsorption rate distribution of the adsorbent N2O4 is made more uniform than in the comparative example. Therefore, it is possible to reduce the concentration of evaporated fuel mainly desorbed from the adsorbent N2O4 at the initial stage of desorption, and to prevent large fluctuations in the air-fuel ratio caused by evaporative fuel with a high concentration being desorbed at the early stage of desorption. Can be done.

Next, another embodiment of the present invention will be described using FIG. 16.

In FIG. 16, the canister 3 (10) has an outer casing 302 and an inner casing 303, as in the embodiment shown in FIG. A second space 308, an adsorbent layer 304, and a third space are formed, and a filter 320 and a filter 3 are formed.
17, upper press plate 214, filter 319, lower press plate 3
16, a filter 318, and an upper holding plate 315 are arranged.

An introduction pipe 310 is formed on the upper surface of the outer casing 302 in the figure. One end 310a of this introduction pipe 310 communicates with the fuel supply pipe 20a of the fuel tank 20 via a pipe 331, and the other end 310b communicates with the fuel supply pipe 20a of the fuel tank 20. Space 308 and adsorbent 3
04 and communicates with the first space 307. Furthermore, the outer casing 302 includes purge pipes 311 and 31.
2 is formed, and one end 311 of the purge pipe 311
a penetrates the adsorbent M304 and communicates with the first space 307, and one end 312a of the purge pipe 312 communicates with a port 340 on the downstream side of the throttle valve 342 of the intake pipe 341 via a pipe 332.

Further, a control valve 335 is provided in a space 333 formed between the purge pipes 311 and 312 to control the flow rate of evaporated fuel sucked into the intake pipe 340. This control valve 335 has a solenoid 336 and a solenoid 33.
By applying electricity to purge pipes 311 and 3,
12, and a valve body 337 that communicates with 12. A heat sink 338 made of a material with high thermal conductivity, such as Af or Cu, is wound around the outer periphery of the solenoid 336, and this heat sink 338 extends into the adsorbent layer 304 and is buried therein. ing.

An atmospheric port 313 is formed on the lower surface of the outer casing 302 in the figure, and this atmospheric port 313 is open to the atmosphere.

Next, the operation of this embodiment will be explained.

The evaporated fuel introduced through the introduction pipe 310 is transferred to the introduction pipe 3
10 is discharged from the open end 310b into the first space 307. The discharged evaporated fuel collides with the inner wall of the bottom portion 330 of the inner casing 303, which acts as a deflection plate, and is uniformly diffused within the space 307, reducing the flow velocity.

After that, the evaporated fuel is transferred to the lower press plate 316 and the filter 319.
The adsorbent flows from below to above the adsorbent layer 304 through the adsorbent layer 304, and the adsorption phenomenon gradually progresses.

Furthermore, the evaporated fuel leaking from the adsorbent layer 304 is
After being discharged into the space 308 and diffusing, the adsorbent N305
It is adsorbed by.

On the other hand, when the engine is operating, the solenoid 336 of the control valve 335 is energized depending on the operating state of the vehicle, and the valve body 33 is energized.
7 is suctioned and the purge pipes 311 and 312 are brought into communication. Therefore, the negative pressure generated in the intake pipe 5 is transferred to the pipe 332.
and canister 3 (
10), whereby the atmosphere is introduced into the atmosphere port 3.
13 will be introduced. This atmosphere is distributed to the third space 309, the adsorbent layer 305, the second space 308, the adsorbent layer 304, and the third space.
The evaporated fuel that has sequentially passed through the space 307 and has been mainly adsorbed on the adsorbent layer 304 is transferred to the purge pipes 311 and 312.
and is sucked into the intake pipe 340.

At this time, as the control 335 energizes the solenoid 336, the heat sink 338 wound around the outer periphery of the solenoid 336 is gradually heated by the heat generated by the solenoid 336, and during the desorption period, the heat sink 338 of the adsorbent layer 304 is heated. The surrounding area is heated.

Generally, when desorbing evaporated fuel adsorbed in a canister, the concentration of the desorbed evaporated fuel is high at the beginning of desorption, but as time passes, the concentration of evaporated fuel decreases rapidly, and the air-fuel ratio becomes significantly lower. It will change. However, according to the embodiment, the heat dissipation plate 338 is removed from the solenoid 3 after detachment.
Since the adsorbent layer 304 is gradually heated by the adsorbent layer 304, the evaporated fuel is actively desorbed from the adsorbent layer 304 over time, and a sudden change in the air-fuel ratio can be prevented.

Figure 17 shows the characteristics showing the relationship between the elapsed time and the air-fuel ratio A/F of the desorbed air when desorbed air is applied at a rate of 101/min to a canister that has adsorbed evaporated fuel at a temperature of 20 to 21 °C. It is a diagram. As is clear from FIG. 17, by providing the heat sink, a sudden change in the air-fuel ratio can be prevented, and the air-fuel ratio can be easily controlled.

Further, in the embodiment described above, since the heat generated by the solenoid 336 of the control valve 335 that controls the flow rate of evaporated fuel to the intake pipe 341 is effectively used, power consumption does not increase. Note that it is desirable that the heat dissipation plate 338 be disposed so as to spread over the entire adsorbent layer 304 in order to improve the efficiency of desorption of evaporated fuel. Furthermore, as shown in FIG. 18, the second introduction port 45 formed in the piping 343, the control valve 344, and the outer casing 302 is also used for the relatively low flow rate of evaporated fuel from the fuel stored in the fuel tank 20. Alternatively, the material may be introduced into the canister 3 (10) through the material and adsorbed thereon.

Next, still another embodiment of the present invention will be described using FIG. 19.

In FIG. 19, the canister 4 (10) has an outer casing 402 and an inner casing 403, as in the embodiment shown in FIG. A second space 408, an adsorbent layer 404, and a third space are formed, and a filter 420 and a filter 4 are formed.
17, upper press plate 414, filter 419, lower press plate 4
16, a filter 418, and an upper holding plate 415 are arranged.

An introduction pipe 410 is formed on the upper surface of the outer casing 402 in the drawing. One end 410a of this introduction pipe 410 communicates with the fuel supply pipe 20a of the fuel tank 20 via a pipe 431, and the other end 410b communicates with the fuel supply pipe 20a of the fuel tank 20. Space portion 408 and adsorbent 4
04 and communicates with the first space 407. Furthermore, a purge port 412 is formed in the outer casing 402, and an inner casing 450 that forms a predetermined space communicating with the purge port 412 is formed.

This internal casing 450 is disposed to penetrate the second space 408 and the adsorbent layer 404, and has a fourth space 451, an adsorbent layer 452, and a fifth space 453 formed therein. Filter 454.455, upper holding plate 456
, a lower press plate 457 is arranged. The fourth space 451 communicates with the first space 407 via a communication hole 458. Further, the purge port 412 communicates with the fifth space 453, and one end 412a of the purge port 412 communicates with the port 440 of the intake pipe 441 on the downstream side of the throttle valve 442 via the piping 432. A control valve 435 is provided in the pipe 432 to control the flow rate of evaporated fuel sucked into the intake pipe 440.

An atmospheric port 413 is formed on the lower surface of the outer casing 402 in the figure, and this atmospheric port 413 is open to the atmosphere.

Next, the operation of this embodiment will be explained.

The evaporated fuel introduced through the introduction pipe 410 is
The liquid is discharged from the opening @1410b of No. 10 into the first space 407. The discharged evaporated fuel collides with the inner wall of the bottom portion 430 of the inner casing 403, which acts as a deflection plate, and is uniformly diffused within the space 407, reducing the flow velocity.

After that, the evaporated fuel passes through the upper holding plate 416 and the filter 419.
The adsorbent flows from below to above the adsorbent layer 404 through the adsorbent layer 404, and the adsorption phenomenon gradually progresses.

At this time, a part of the vaporized fuel diffused in the space 407 flows into the fourth space 51 through the communication hole 458 and is adsorbed by the adsorbent layer 452, but most of it flows into the adsorbent layer 404. It flows in and is adsorbed.

Furthermore, the evaporated fuel leaked from the adsorbent layer 404 is
After being discharged into the space 408 and diffusing, the adsorbent layer 405
It is adsorbed by.

On the other hand, when the engine is operating, the control valve 435 is opened depending on the operating state of the vehicle, and negative pressure in the intake pipe 441 is applied to the port 440.
, is introduced into canister 4 (10) through purge port 412. Therefore, mainly the adsorbent layers 404, 4
The evaporated fuel adsorbed in 05 is sucked into the intake pipe 441 together with the atmosphere that has flowed in from the atmosphere port 413.

At this time, the evaporated fuel passes through the communication hole 458 to the adsorbent layer 45.
However, at the initial stage of desorption, the adsorbent layer 452 has a small adsorption residual rate (high adsorption capacity), so the adsorbent N404.40 passes through N404.
A part of the vaporized fuel desorbed from the adsorbent layer 452
Thereafter, as the adsorption residual rate increases, the amount of re-adsorption decreases, and the amount of desorption gradually increases. Therefore, it is possible to prevent fluctuations in the air-fuel ratio caused by desorption of highly concentrated evaporated fuel at the initial stage of desorption. Note that if the adsorption efficiency of the adsorbent N452 is too good, the evaporated fuel will not be desorbed sufficiently, so the adsorbent filled in the adsorbent layer 452 will be smaller than the adsorbent filled in the adsorbent layers 404 and 405. has a weak adsorption power for evaporated fuel,
The material is also set to have good desorption properties (for example, when coconut shell-based activated carbon is used for the adsorbent layers 404 and 405, the adsorbent layer 452 is filled with coal-based activated carbon with large pores). do).

Furthermore, as shown in FIG.
It may also be possible to communicate via. With this setting, the same adsorbent can be used by installing the main canister 460 in a place with a low ambient temperature and installing the sub-canister 470 in a place with a high ambient temperature.

Furthermore, as shown in FIG.
3. Canister 4 (10) via control valve 444 and second introduction port 445 formed in outer casing 302
It may also be introduced into the interior and adsorbed.

Next, still another different embodiment of the present invention will be described using FIG. 22.

In FIG. 22, the canister 5 (10) is a cylindrical casing 501 made of resin or iron plate.
Inside the casing 501, an adsorbent layer 504 is formed of an adsorbent 503 made of, for example, activated carbon.

A partition plate 511 is provided inside the casing 501, and this partition plate 511 divides the adsorbent layer 504 into two layers: an A layer 504a (!=B layer 504b). AN 504 a and 8 layers 5
The adsorbent layer filling ratio of 04b is set to be 1.5 to 2.5:1.

A filter 515 is disposed on the upper surface of the adsorbent layer 504a in the figure, and a porous diffuser 506 that acts with the deflection plate of this embodiment is disposed on the lower surface in the figure. Further, a porous diffuser 505 is disposed on the upper surface of the adsorbent layer 504b in the figure, and a filter 510 is disposed on the lower surface in the figure.

Above the porous diffuser 5050 in the figure, there is a first space 507.
is formed, and a second space 508 is formed below the filter 510 and the porous diffuser 506 in the figure.
Further, above the filter 515 in the figure, a third space 5 is provided.
09 is formed.

An introduction port 512 and a purge port 513 communicating with the first space 507 are formed on the upper surface of the casing 501, and an atmospheric port 502 communicating with the atmosphere is formed. One end 512a of the introduction port 512 communicates with the fuel supply pipe 20a of the fuel tank 20 via a pipe 531, and one end 513a of the purge port 513 communicates with an intake pipe 541 via a pipe 532. Further, a switching valve that is opened only during refueling is provided in the pipe 531, and a control valve 535 that controls the flow rate of evaporated fuel sucked into the intake pipe 541 is provided in the pipe 532.

Next, the operation of this embodiment will be explained.

Evaporated fuel generated in the fuel tank 20 during refueling is transferred to the pipe 5.
31. Canister 5 (10) through introduction port 512
and is discharged into the first space 507. After the flow of the discharged evaporated fuel is dispersed by the porous diffuser 505 acting as a deflection plate, the flow is dispersed in the adsorbent layer 504a.
It is adsorbed almost evenly. In addition, the adsorbent layer 504a
The evaporated fuel leaking out is discharged into the second space 508 and diffused, and then adsorbed by the adsorbent 11504b.

On the other hand, when the engine is operating, the control valve 535 is opened depending on the operating state of the vehicle, and the negative pressure in the intake pipe 541 is transferred to the port 54.
0, canister 5 (10) through purge port 513
be introduced within. Therefore, the evaporated fuel adsorbed on the adsorbent layer 504 is sucked into the intake pipe 541 together with the air flowing in from the air port 502.

In the above embodiment, the adsorbent layer 504 is divided by the partition plate 511 so that the adsorbent filling ratio of the A layer 504a and the 8th layer 504b is 5 to 2.5:1. The adsorption efficiency of layer 504 is further improved. FIG. 23 shows the A layer 504a and the 8th layer 504b of the adsorbent layer 504 in the canister 5 (10) of this embodiment.
This shows the experimental results of the adsorption performance when the adsorbent filling ratio is set to 2=1. The weight is measured, and the value obtained by subtracting the weight after desorption at a predetermined air flow rate from the weight, that is, the relationship between the adsorption/desorption capacity and the temperature of the supplied fuel is shown. In addition, in the figure, sample 1 shows the adsorption performance of the canister of the type shown in FIG. 3, and sample 2 shows the amount of adsorbent filled in the A layer 504a and the 8th layer 504b of the adsorbent layer 504 in canister 5 (10) of this example. Adsorption performance when the ratio is set to 1:l, sample 3 is the adsorption agent AN504a of N504 in canister 5 (10) of this example.
The graph shows the adsorption performance when the adsorbent filling ratio of the eight layers 504b is set to 2:l and the porous diffusers 505 and 506 are removed.

As shown in FIG. 23, by providing porous diffusers 505 and 506 and setting the adsorbent filling ratio of the A layer 504a and the 8th layer 504b of the adsorbent layer 504 to 2=1, the adsorption efficiency can be increased. This is improved by about 25% compared to sample 1.

Here, a large amount of evaporated fuel generated during refueling is first adsorbed in the A layer 504a of the adsorbent layer 504, and then
04b, the adsorption rate of the adsorbent layer gradually decreases along the flow of the evaporated fuel. Therefore, by setting the adsorbent filling amount on the introduction side of the evaporated fuel to be large and setting the adsorbent filling amount on the downstream side to be small, the adsorption rate of the adsorbent layer will become uniform and the adsorption efficiency of the adsorbent layer will further improve. . Therefore, as in this embodiment, the A layer 50 on the introduction port 512 side
4a and the downstream 8 layer 504b, the adsorbent filling ratio is 1.
．． By setting 5 to 2.571, the adsorbent N50
The adsorption efficiency of No. 4 is significantly improved.

In addition, as shown in FIG. 24 or FIG. 25, the second space 508 is eliminated, the adsorbent filling amount on the introduction port 512 side is set large, and the adsorbent filling amount on the atmospheric port 502 side is set small. However, the adsorption rate of adsorbent N504 is made uniform and the adsorption efficiency is improved.

〔Effect of the invention〕

As explained above, according to the present invention, a diffusion chamber is formed at a position opposite to the opening position of the introduction port in the space, which is a simple configuration, and the evaporated fuel introduced from the introduction port is absorbed into the adsorbent in the diffusion chamber. Since the velocity component caused by the adsorption is reduced and the adsorption is done almost uniformly overall by the adsorbent, the adsorption efficiency of the adsorbent becomes very high. Therefore, even a large amount of vaporized fuel with a high inflow speed can be sufficiently absorbed without increasing the size, which is an excellent effect.

[Brief explanation of the drawing]

Figures 1 to 8 relate to embodiments of the present invention.
The figure is a sectional view showing the configuration of this example, Figure 2 is a configuration diagram showing the entire system incorporating this example, and Figures 3 and 4 are each a comparative study with this example. 5 is a diagram for explaining the experimental method, FIG. 6 is a diagram for showing the experimental results, FIG. 7 is a diagram for explaining the operation of this example, and FIG. 8 is a diagram for explaining the experimental method. This figure is a diagram for explaining the operation of the canister shown in FIG. 3. FIGS. 9 to 11 are sectional views showing the configurations of other embodiments of the present invention. FIG. 12 and FIG. 13 are characteristic diagrams each showing the adsorption characteristics of a conventional canister. FIG. 14 and FIG. 15 relate to yet another embodiment of the present invention. FIG. 14 is a sectional view showing the configuration of this embodiment, and FIG. 15 is a characteristic showing the vaporized fuel adsorption rate of this embodiment. It is a diagram. 16 to 18 relate to still another embodiment of the present invention. FIG. 16 is a sectional view showing the configuration of this embodiment, and FIG. 17 is a diagram showing the energization time to the solenoid and the release of air from the canister. FIG. 18 is a cross-sectional view showing a modification of this embodiment. 19 to 21 relate to still another embodiment of the present invention, and FIG. 19 is a sectional view showing the configuration of this embodiment;
FIG. 20 and FIG. 21 are diagrams each showing a modification of this embodiment. Fig. 22 to Fig. 25 relate to still another different embodiment of the present invention, Fig. 22 is a sectional view showing the configuration of this embodiment, and Fig. 23 is a characteristic diagram showing the adsorption characteristics of this embodiment. , FIG. 24, and FIG. 25 are diagrams each showing a modification of this embodiment. 1 (10)...Canister, 1...Casing, l
a... Bottom surface (direction changing plate), 3... Adsorbent, 4... Adsorbent layer, 9... First space, 10... Second space, 11... Partition plate, 12...introduction pipe. Representative Patent Attorney Takashi Okabe Figure 5 Figure 6 Figure 7 Figure 8 D Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 C'-Sil-041" 211
"Compendium" Chi 1-213 Cough 1 Row 204 Figure 15 Figure 16 Noi Kasumasa To I Berevenge Kaede Relatives Q Arc Tomi Figure 20 921 Figure i @ Remains of Gasososhi Haruto ℃

Claims (12)

[Claims] (1) a casing having an introduction port for introducing evaporated fuel from a fuel tank; a evaporated fuel adsorbent disposed within the casing to adsorb the evaporated fuel introduced from the introduction port; The fuel vaporizer is characterized by comprising a diffusion chamber that is formed at the port opening and that diffuses the evaporated fuel introduced from the introduction port to reduce the velocity component of the evaporated fuel in the adsorption direction by the evaporated fuel adsorbent. Evaporated fuel processing equipment for vehicles. (2) The fuel vapor processing device for a vehicle according to claim 1, wherein the direction of introduction of the fuel vapor from the introduction port in the diffusion chamber and the direction of adsorption by the fuel vapor adsorbent are substantially opposite directions. (3) The evaporated fuel adsorbent is divided into multiple layers so as to communicate in series, and the evaporated fuel diffused in the diffusion chamber is sequentially adsorbed from one end of the evaporated fuel adsorbent divided into multiple layers. The evaporative fuel processing device for a vehicle according to claim 1 or 2, characterized in that: (4) The introduction port is connected to the fuel tank via a switching valve that is opened only when refueling, and the evaporated fuel generated during refueling is introduced through the introduction port, 4. The vehicular evaporative fuel processing device according to 2 or 3. (5) A deflection plate is provided in the diffusion chamber at a position opposite to the opening position of the introduction port, and the evaporated fuel introduced from the introduction port collides with the deflection plate and diffuses within the diffusion chamber. The evaporative fuel processing device for a vehicle according to claim 1, 2, 3, or 4, characterized in that: (6) The introduction port is constituted by an introduction pipe inserted into the casing from the outside, and this introduction pipe penetrates through the first adsorbent and opens into the diffusion chamber, and the introduction pipe is inserted from the introduction pipe. The evaporated fuel collides with the inner wall of the casing that acts as a deflection plate and diffuses in a diffusion chamber, and is then adsorbed by the first adsorbent in a flow direction opposite to the direction of introduction from the introduction pipe. The evaporative fuel processing device for a vehicle according to claim 1, 2, 3, 4, or 5. (7) The evaporative fuel processing device for a vehicle according to claim 5, wherein the deflection plate is a porous diffuser. (8) The evaporated fuel adsorbent is divided into two layers, a first adsorbent and a second adsorbent, and the evaporated fuel diffused in the diffusion chamber is absorbed by the first adsorbent and the second adsorbent. The evaporative fuel processing device for a vehicle according to claim 2, wherein the fuel vapor is sequentially adsorbed and the filling ratio of the first adsorbent and the second adsorbent is 1.5 to 2.1:1. . (9) Inside there is a first space, a first vaporized fuel adsorbent, and a second space.
A space, a second vaporized fuel adsorbent, and a third space are formed to communicate in series, and an introduction port opens into the first space and communicates with the fuel tank, and the third space an atmospheric port that opens at the bottom and communicates with the atmosphere;
a casing having a purge port that opens into the first space and releases the evaporated fuel adsorbed by the evaporated fuel adsorbent into the intake pipe by negative pressure in the intake pipe; A fuel vapor processing device for a vehicle, characterized in that the fuel vapor processing device is a diffusion chamber that diffuses fuel vapor introduced from a port and reduces a velocity component of the fuel vapor in a direction in which the fuel vapor is adsorbed by the fuel vapor adsorbent. (10) The evaporative fuel treatment for a vehicle according to claim 9, wherein the casing is provided with an electromagnetic valve that controls the flow rate of the evaporated fuel sucked into the intake pipe through the purge port according to the driving state of the vehicle. Device. (11) The solenoid valve has an electromagnetic coil and a valve body that moves and is attracted into the intake pipe by energizing the electromagnetic coil,
10. The vehicular fuel vapor processing apparatus according to claim 9, wherein a heat dissipation plate made of a material with good thermal conductivity and embedded in the first adsorbent is provided around the outer periphery of the electromagnetic coil. (12) In the path from the purge port to the intake pipe, there is a
10. The vehicular fuel vapor processing apparatus according to claim 9, further comprising a sub-canister having an adsorbent having a weaker adsorption force for the vaporized fuel and better desorption properties than the second adsorbent.