JPH09203353A - Vehicular canister - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten oil supply time in a vehicular canister in which evaporative fuel is passed from an upstream side absorbent layer through a downstream side absorbent layer via a gas flow resistance part, by providing a bypass pass which bypasses the gas flow resistance part and the downstream absorbent layer, and providing a valve opened at the time of oil supplying on the way of the bypass pass. SOLUTION: When raw fuel in a fuel tank 27 is evaporated during an oil non- supplying period, evaporated fuel and air are sucked in the diffusion chamber 9 of a canister through a communicating passage 26, and discharged from a releasing port 37 by being passed through an absorbent 8 layer, a dispersion chamber 10, an absorbent 17 layer, a dispersion chamber 19, a restrictor 23, a diffusion chamber 20, an absorbent 18 layer and a diffusion chamber 21. Next, when oil is supplied while an engine is stopped, a great deal of evaporative fuel is generated in the fuel tank 27, and a valve 43 opened at the time of oil supplying is operated to be opened when the inside of a canister case 1 becomes positive pressure higher than the oil non- supplying period, and the inside of a bypass passage 24 becomes a specified high pressure or more. Hereby, gas flow resistance is lowered in comparison with gas flow resistance led to flow through the restrictor 23, therefore, such inconvenience is solved that oil supply hours are lengthened.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle canister that processes vaporized fuel generated from a fuel tank or the like so as not to be released into the atmosphere.

2. Description of the Related Art Conventionally, in a fuel tank for storing fuel to be supplied to an internal combustion engine of an automobile or the like, vaporized fuel generated in the fuel tank is collected by a canister, and the vaporized fuel collected during engine operation is collected. I try to purge it to the engine. In such a canister, in order to prevent blow-through of evaporated fuel, a sub-adsorbent layer is provided separately from the main adsorbent layer by a partition wall, and a small-diameter throttle passage is provided in the partition wall. A diffusion chamber is installed in the upstream part of
It is known that the evaporated fuel sucked into the canister flows through the main adsorbent layer → diffusion chamber → throttle passage → sub-adsorbent layer (for example, JP-A-5-187330).

The generation of evaporative fuel in the fuel tank can be considered when the fuel is not refueled and when it is normally refueled. In the former case, the amount of evaporative fuel generated per unit time is Although the amount is small, the amount of evaporated fuel generated per unit time in the latter is extremely large. Therefore, in the canister provided with the sub-adsorbent layer, the partition wall, the throttle, and the like as in the above-described conventional case, even if the evaporated fuel is favorably adsorbed at the time of non-refueling, at the time of refueling, the above-mentioned throttle passage or The secondary adsorbent layer, etc. has a large ventilation resistance, and it becomes impossible to suck in a large amount of evaporated fuel at a high pressure in a short time into the canister, which increases the internal pressure of the fuel tank and prolongs the refueling time.
In some cases, refueling may stop automatically. Therefore, the present invention satisfactorily sucks the evaporated fuel generated in the fuel tank into the canister both at the time of non-fueling and at the time of fueling, and at the time of fueling, the fueling time becomes longer as described above or the fueling stops automatically. It is an object of the present invention to provide a vehicle canister that prevents this.

In order to solve the above-mentioned problems, the first invention provides a plurality of adsorbent layers and a ventilation resistance section between the adsorbent layer on the upstream side and the adsorbent layer on the downstream side. In the canister which is provided with the vaporized fuel and the air generated in the fuel tank and passes from the adsorbent layer on the upstream side to the adsorbent layer on the downstream side through the ventilation resistance portion and is released to the atmosphere, the adsorbent on the upstream side is provided. A bypass passage (24) that opens from the (8, 17) layer to the atmosphere by bypassing the ventilation resistance portion (23) and the downstream adsorbent (18) layer is provided, and the bypass passage (24) includes the bypass passage (24). When the inside of the passage (24) becomes a predetermined positive pressure, an opening valve (43) for refueling that is opened by the pressure is provided.
In the present invention, when the engine is stopped and fuel is not supplied, the evaporated fuel and air flow through the ventilation resistance portion (23), and the adsorbent (8, 17) layer on the upstream side mainly adsorbs the evaporated fuel. It is also collected and the evaporative fuel is prevented from blowing through. During refueling while the engine is stopped, the pressure inside the bypass passage (24) is increased and the opening valve (43) during refueling is opened, so that the pressure in the upstream adsorbent (8, 17) layer is increased by the bypass passage (24). ) Is released into the atmosphere. Therefore, there is no ventilation resistance due to the ventilation resistance portion (23) or the adsorbent (18) layer on the downstream side, and the pressure increase in the fuel tank (27) is suppressed. A second invention provides a partition wall (2) in a canister case (1), a first adsorbent (8) layer is provided on one side thereof, and a second adsorbent (17) layer is provided on the other side thereof. The third adsorbent (18) layers are provided in multiple layers, and the downstream side of the first adsorbent (8) layer and the upstream side of the second adsorbent (17) layer are communicated with each other, and the second adsorbent (18 17)
The layer and the third adsorbent (18) layer are communicated with each other via the ventilation resistance portion (23), the downstream of the third adsorbent (18) layer is communicated with the atmosphere, and the second adsorbent (17) ) Layer is provided with a bypass passage (24) that bypasses the ventilation resistance portion (23) and the third adsorbent (18) layer and opens to the atmosphere, and the inner diameter of the bypass passage (24) is set to the ventilation resistance portion ( 23) is larger than the ventilation diameter in 23), and further in the bypass passage (24),
An opening valve (43) for refueling is provided, which opens when the pressure in the bypass passage (24) reaches a predetermined positive pressure.
Further, upstream of the first adsorbent (8) layer, a small diameter first evaporated fuel intake port (25) communicating with the gas phase portion of the fuel tank (27) and a large diameter second evaporated fuel intake. Port (2
9) is provided. In the present invention, in addition to the operation of the first invention described above, the upstream adsorbent layer has the first adsorbent (8) layer and the second adsorbent (17).
It is formed in a large capacity by two layers, a layer and a layer, and at the time of refueling, the evaporated fuel and the air can be adsorbed and collected efficiently before passing through the bypass passage (24), and the evaporated fuel can be collected into the atmosphere. The amount of release can be extremely small. Further, by providing the large-diameter second evaporated fuel intake port (29) and forming the bypass passage (24) with a diameter larger than that of the ventilation resistance portion (23), the canister case at the time of refueling The pressure in (1) is promptly released to the atmosphere, and the pressure increase in the fuel tank (27) is suppressed more favorably.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is based on the embodiment shown in the drawings.
An embodiment will be described. In FIG. 1, 1 is a canis
It is a case. 2 is fixed in the canister case 1
The first adsorbent chamber 3 is formed on one side of the partition wall 2
In parallel with this, the second adsorbent chamber 4 and the third adsorption are provided on the other side.
The agent chamber 5 is partitioned and formed. Above the first adsorbent chamber 3
Filters 6 and 7 are installed at the bottom, and both filters are installed.
The first adsorbent 8 made of activated carbon or the like is filled between 6 and 7.
I have. A first diffusion chamber 9 is formed on the upper side of the upper filter 6.
The second diffusion chamber 10 is provided below the lower filter 7.
Are formed. Reference numeral 11 denotes a coil provided in the second diffusion chamber 10.
The filter 7 is pressed upward by the ill spring.
You. The second adsorbent chamber 4 and the third adsorbent chamber 5 are lower than the former.
Arranged in layers and formed in series, above and below each chamber 4, 5.
Filters 12, 13, 14, 15 are installed in the section
You. The lower side of the filter 13 is formed in the second diffusion chamber 10.
Then, the filter 13 is pushed upward in the second diffusion chamber 10.
A coil spring 16 for pressing is installed. The above
2 There is activity between the filters 12 and 13 in the adsorbent chamber 4.
The second adsorbent 17 made of charcoal or the like is filled. The above
3 Active between the two filters 14 and 15 in the adsorbent chamber 5.
The third adsorbent 18 made of charcoal or the like is filled. Above
A third diffusion chamber 19 is formed above the filter 12, and
A fourth diffusion chamber 20 is formed below the filter 15.
Further, a fifth diffusion chamber 21 is formed above the filter 14.
Have been. 22 is the third diffusion chamber 19 and the fourth diffusion chamber 2
0, that is, the second adsorbent 17 layer portion and the third adsorbent 18
Adsorbed fuel diffusion prevention wall fixed between layers, with a small hole
A diaphragm 23 composed of the second adsorbent 17
3 The air flow rate to 18 layers of the adsorbent is suppressed. This aperture
Reference numeral 23 constitutes a ventilation resistance portion. 24 is a bypass passage
In that way, the adsorbed fuel diffusion prevention wall 22,
5 diffusion chambers 20 and 21, both filters 14 and 15, and a third suction chamber
It penetrates through the 18 layers of the adhesive and its inner end 24a is the third diffusion chamber.
19, and the outer end 24b is outside the canister case 1.
Overhangs. Inner diameter D of the bypass passage 24₁Is above
Inner diameter D of diaphragm 23_FourGreater than, D ₁> D_FourSet to
Has been done, specifically D₁= Φ16
You. Next, each port will be described. 25 is the first expansion
The first evaporative fuel intake port, which is open to the dispersion chamber 9,
Communicating with the gas phase portion 28 of the fuel tank 27 through the passage 26
ing. Numeral 29 denotes a second opening which communicates with the first diffusion chamber 9
Evaporative fuel intake port, fuel tank through communication passage 30
Located in the gas phase portion 28 of 27 and near the fuel injection pipe 31
And communicate with the opening. This second evaporative fuel intake port
29 and the inner diameter D of the communicating passage 30_ThreeIs the first evaporation fuel
Inner diameter D of the material intake port 25 and its communication passage 26_FourGreater than
Kiku, D_Three> D_FourIs set to, specifically D_Three=
It is formed in φ16. 32 opens in the first diffusion chamber 9
The purge port communicates with the engine E through the communication passage 33.
To the intake manifold 34.
The air port 35 is open to the fifth diffusion chamber 21 and communicates therewith.
Communicates with the open port 37 via the check valve 36
doing. The check valve 36 is a canister case.
When the pressure inside the space 1 becomes positive, the pressure causes it to open and empty.
Allows distribution from the air port 35 to the open port 37
It is a normally closed valve. 38 is an air intake port,
From the air port 35 through the control valve 39
It communicates with the branched passage 35a, and its outer end is a communication passage.
An opening 40 communicates with an air cleaner 41. Up
The control valve 39 is a diaphragm valve.
Closed at all times by the diaphragm spring
When a predetermined negative pressure acts on the negative pressure chamber 39b, the die
The diaphragm is sucked against the afram spring
The valve 39a is adapted to open. In addition, the negative pressure
The chamber 39b communicates with the first diffusion chamber 9 through the passage 42.
I have. 43 is an outer end 24b of the bypass passage 24.
A valve that opens when refueling is provided in the opening.
Valve 43a is a diaphragm spring.
The opening 24b of the bypass passage 24 is closed by S.
Has been energized. Also, the diaphragm chamber 43b is in the atmosphere.
From the inlet 44 to the fuel tank 27 through the communication passage 44a
The fuel injection pipe 31 communicates with the vicinity of the fuel filler port. Next
The operation will be described. Inside the fuel tank 27 when not refueling
Since the internal pressure of the gas phase portion 28 of the
The internal pressure in the nister case 1 is also a low positive pressure. this
At the time of refueling, the diaphragm chamber 43b in the open valve 43
A fuel tank is provided in the interior through the communication passage 44a and the air inlet 44.
The internal pressure of the cylinder 27 (substantially the same as the internal pressure in the canister above) is generated.
Oil supply by the urging force of the diaphragm spring S
The diaphragm valve 43a of the time release valve 43 is as shown in the figure.
It is kept closed. The engine is not refueled and the engine is stopped.
When the fuel tank 27 is stopped, the raw fuel in the fuel tank 27 evaporates and its vapor phase part
When the pressure in 28 rises and the pressure in the canister 1 becomes equal,
The check valve 36 opens due to the pressure difference between the pressure and the atmospheric pressure.
It operates and the inside of the canister 1 communicates with the open port 37.
By this communication, the vapor phase portion 28 in the fuel tank 27 is vaporized.
The generated fuel and air pass through the communication passage 26 to suck the first evaporated fuel.
Inhaled from the inlet port 25 into the first diffusion chamber 9 of the canister.
As shown by the path of the solid arrow, the filter 6, the first adsorbent
8 layers, filter 7, second diffusion chamber 10, filter 13,
2 layers of adsorbent 17, filter 12, third diffusion chamber 19, diaphragm
23, fourth diffusion chamber 20, filter 15, third adsorbent 18
Layer, filter 14, fifth diffusion chamber 21, air port 35,
Check valve 36 to open port 37 to atmosphere
Flows. Due to the above-mentioned flow, the evaporated fuel is absorbed by each adsorbent 8
And 17 and 18 are adsorbed and collected, containing almost no evaporated fuel.
The remaining air flows out from the open port 37. At this time,
The flow path from the 17th layer of the second adsorbent to the 18th layer of the third adsorbent is small
Since the diameter of the diaphragm is 23, the third adsorbent 18 layers
Flow into the first adsorbent 8 and the second adsorbent 17 is suppressed.
The large amount of adsorbent collects the evaporated fuel, and the adsorption efficiency
Is done well. In addition, this throttle 23 allows the evaporated fuel to be evaporated.
It is also possible to prevent the material from passing through. Next, refuel with the engine stopped
Then, a large amount of evaporated fuel is generated in the fuel tank 27.
However, the pressure in the gas phase portion 28 suddenly rises, and the canister
The positive pressure in the source 1 becomes higher than that in the unlubricated state. Also burning
When the refueling cap of the fuel tank 27 is removed, atmospheric pressure continues.
Refueling time open bar through passage 44a and air inlet 44
It is introduced into the diaphragm chamber 43b of the sleeve 43. That
Therefore, the pressure inside the bypass passage 24 becomes higher than the predetermined value (positive pressure).
Then, due to the differential pressure, the valve 43a of the open valve 43 during refueling is
Open operation. By this opening operation, the gas phase of the fuel tank 27
The vaporized fuel and air in the portion 28 pass through the communication passage 30 to the second
From the evaporated fuel suction port 29, the first diffusion chamber 9 of the canister
Inhaled into the filter, like the path of the one-dot chain line arrow
6, first adsorbent 8 layers, filter 7, second diffusion chamber 10, flap
Filter 13, second adsorbent 17 layers, filter 12, third expansion
A sprinkling chamber 19, a bypass passage 24, a refueling opening valve 43,
Flow from the open port 37 to the atmosphere through the communication port 37a
You. In addition, the pressure inside the canister case 1 is increased.
Then, the check valve 36 also opens, and the path indicated by the solid arrow
Therefore, the evaporated fuel and the air flow. As mentioned above, large
The diameter and bypasses the throttle 23 and the third adsorbent 18 layer
By flowing through the bypass passage 24, the ventilation resistance
The resistance is extremely higher than the ventilation resistance that flows through the throttle 23.
And the amount of degassing per unit time increases. That
Therefore, the pressure increase in the fuel tank 27 is suppressed,
Refueling is automatically stopped and faster than the conventional one
Nothing to do. In addition, the fuel vapor
The flow consists of two layers, a first adsorbent 8 layer and a second adsorbent 17 layer.
Because it passes through a large volume of adsorbent consisting of layers,
The amount of fuel adsorbed and collected also increases, and the amount of evaporated fuel released to the atmosphere
Is also extremely low. Next, when the engine is running in the unlubricated state
Is a negative pressure generated in the intake manifold 34,
From the purge port 32 through the communication passage 33 to the first diffusion chamber 9
Acts within. This negative pressure is controlled through the passage 42.
The valve 39a by opening the valve 39a.
Operate. In addition, the negative pressure described above is stored in the canister case 1.
Also works, check valve 36 and refueling open valve 43
Is kept closed. And as above
When the valve 39 opens, the canister
Due to the differential pressure between the negative pressure in the base 1 and the atmospheric pressure, the air cleaner
Clean air inside 41 sucks air through communication passage 40
Inhaled into the port 38, like the path of the two-dot chain line arrow,
Control valve 39 opened, passage 35a, air
Port 35, fifth diffusion chamber 21, filter 14, third adsorption
18 layers of agent, filter 15, fourth diffusion chamber 20, diaphragm 23,
The third diffusion chamber 19, the filter 12, the second adsorbent 17 layer, the filter
Filter 13, second diffusion chamber 10, filter 7, first adsorbent
8 layers, filter 6, first diffusion chamber 9, purge port 32,
Intake into intake manifold 34 through communication passage 33
And supplied to the engine E. By this air flow, each
The evaporated fuel that has been adsorbed and collected by the adsorbents 8, 17 and 18 is
It is disengaged and purged into engine E with air. The above
In the embodiment, the refueling opening valve 43 is provided as a diaphragm.
The following effects are obtained by using the valve of the formula.
At the time of refueling, the open valve 43 is filled with the adsorbent in the canister.
Since dehumidified dry air acts, it will not adhere to the valve.
Foreign matter tends to dry and solidify. Therefore, this bar
If a solenoid valve is used as a
Foreign matter may dry up and solidify on the parts, causing sliding failure of the solenoid valve.
It has On the other hand, as mentioned above, the diaphragm type
When using the valve of
Since there are no functional parts that can
There is an expected effect.

As described above, according to the first aspect of the present invention, blow-through of evaporated fuel can be prevented and refueling can be smoothly performed. Furthermore, since a pressure valve that opens and closes by the pressure generated during refueling is used as the valve that opens and closes the bypass passage, it is simpler than an electrically operated valve. According to the second aspect of the present invention, the adsorption efficiency of the evaporated fuel can be further improved, and the refueling can be performed more smoothly.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

[Explanation of symbols]

 1 canister case 2 partition wall 8 first adsorbent 17 second adsorbent 18 third adsorbent 23 airflow resistance part 24 bypass passage 25 first evaporative fuel intake port 27 fuel tank 28 gas phase part 29 second Evaporative fuel intake port

Claims (2)

[Claims] 1. A plurality of adsorbent layers are provided, and a ventilation resistance portion is provided between the adsorbent layer on the upstream side and the adsorbent layer on the downstream side, so that the evaporated fuel and air generated in the fuel tank can be disposed on the upstream side. In a canister which passes from the adsorbent layer to the adsorbent layer on the downstream side through the ventilation resistance section and releases it to the atmosphere, the canister that opens from the adsorbent layer on the upstream side to the atmosphere by bypassing the ventilation resistance section and the adsorbent layer on the downstream side A canister characterized in that a bypass passage is provided, and an opening valve for refueling is provided in the bypass passage when the inside of the bypass passage reaches a predetermined positive pressure and the valve is opened at the time of refueling. 2. A partition wall is provided in a canister case, a first adsorbent layer is provided on one side of the partition wall, and a second adsorbent layer and a third adsorbent layer are provided on the other side in a multi-layered manner. The downstream side of the first adsorbent layer and the upstream side of the second adsorbent layer are communicated with each other, the second adsorbent layer and the third adsorbent layer are communicated with each other through the ventilation resistance part, and the third adsorption is performed. A bypass passage communicating with the atmosphere downstream of the agent layer and bypassing the ventilation resistance portion and the third adsorbent layer from the second adsorbent layer to open to the atmosphere is provided, and the inner diameter of the bypass passage is ventilated. A diameter larger than the ventilation diameter in the resistance portion is provided, and further, in the bypass passage, there is provided a refueling opening valve that opens at the pressure when the inside of the bypass passage reaches a predetermined positive pressure, and further, the first adsorption A small-diameter first evaporated fuel intake port and a large-diameter second evaporated fuel intake port that communicate with the gas phase portion of the fuel tank are provided upstream of the agent layer. A canister featuring an inlet port.