JPH11200963A - Canister - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration of purge performance, deterioration of adsorptive ability of vaporized fuel, etc., caused by blocking due to dust or the like of a filter in an atmospheric port side in a canister having an inner/outer double cylindrical main body casing. SOLUTION: In an upper part of a main body casing 20, a filter storage casing 39, a space part communicating with an atmospheric port 38 to be formed with the space part having a cross sectional area larger than a cross sectional area of an inner cylinder 21, is fixedly mounted. In this filter storage casing 39, so as to store almost a semicircular pre-filter 41 with a surface direction thereof extended along a cross section of this casing 39.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a canister as an evaporative fuel adsorbing means used for treating evaporative fuel from a fuel system of an internal combustion engine, and more particularly, to a canister having an inner / outer double cylindrical main body casing. Regarding canisters.

[0002]

2. Description of the Related Art Conventionally, in an automobile, an evaporative fuel treatment apparatus for preventing evaporative fuel from a fuel system such as a fuel tank from being released into the atmosphere has been used, and a canister is provided as means for adsorbing the evaporative fuel. Are known. As such a canister, there is a canister having a single adsorbent layer made of activated carbon or the like (see Japanese Patent Application Laid-Open No. 7-122017).

[0003] However, such a single adsorbent layer has a problem that the size of the canister becomes large and various canisters corresponding to the fuel capacity must be prepared. Therefore, two of the relations connected in series to each other
As an example of a canister having two adsorbent layers and solving the above problem, as shown in FIG. 5, the main body casing 1 has an inner / outer double cylindrical structure of an inner cylinder 2 and an outer cylinder 3. A known canister is known. In the case of this canister, a space between the inner cylinder 2 and the outer cylinder 3 and a space in the inner cylinder 2 are respectively filled with an adsorbent, and are partially formed with each other. A charge port 6 having adsorbent layers 4 and 5 communicating with each other, and allowing the adsorbent to inhale evaporative fuel generated in the fuel system of the internal combustion engine; and purging evaporative fuel adsorbed by the adsorbent in the intake system of the internal combustion engine. A barge port 7 is provided in communication with an adsorbent layer 4 formed in a space between the inner cylinder 2 and the outer cylinder 3, and an atmosphere port 8 for drain and fresh air introduced to the atmosphere. To the adsorbent layer 5 formed in the space inside the inner cylinder 2 It has a structure in which by (see Japanese Patent Laid-Open No. 6-249088, etc.).

In a canister having such an inner / outer double cylindrical main body casing 1, a filter 9 provided on the atmosphere port 8 side for collecting dust and the like is conventionally provided with an upper part of the main body casing 1 as shown in FIG. Between the air port 8 and the adsorbent layer 5 inside the inner cylinder 2.

[0005]

However, as described above, in the canister having the inner / outer double cylindrical main body casing 1, the air port 8 on the upper part of the main body casing 1 and the adsorbent layer 5 on the inner side of the inner cylinder 2 are provided. In the case where the filter 9 is provided between the two, there are the following problems. That is, inside and outside 2
The inner cylinder 2 of the heavy cylindrical main casing 1 has a relatively small cross-sectional area, and the filter 9 disposed along this cross-section has a small collecting area, and is inferior in dust collecting performance.

Further, as described above, since the filter 9 has a small collecting area and its collecting surface faces upward, the filter 9 is easily clogged with dust 10 and the like. At the time of gas purging from the canister, air introduced from the atmospheric port 8 flows through the adsorbent layers 5 and 4 in order, so that the purge gas is guided from the barge port 7 to the intake system of the internal combustion engine so as to accompany the air. However, when the filter 9 is closed as described above, the ventilation resistance value (purge pressure loss) between the atmosphere port 8 and the purge port 7 increases, and it becomes impossible to properly secure the air for purging. As a result, the ability to adsorb the evaporated fuel is reduced.

In order to solve such a problem, as shown in FIG. 6, a filter chamber 13 containing a dust filter 12 is provided in the middle of a pipe 11 communicating with the atmosphere port 8 separately from the canister. Is thought to be. However, in such a configuration in which the separately provided dust filter 12 is provided, it is necessary to provide the conduit 11 and the filter chamber 13 separately from the main casing 1 of the canister.
This increases the number of connecting portions of the pipes, and increases the cost.

In addition, there is a problem that the pressure loss increases due to expansion and contraction of the open-to-atmosphere path, resulting in a decrease in gas purge performance and a decrease in the adsorbability of the evaporated fuel. In addition to the above problems, the canister having the inner / outer double cylindrical main body casing also has the following problems. That is, when water is collected at the bottom of the main body casing 1 due to, for example, water being sucked in from the atmosphere port 8, the ventilation resistance (purge pressure loss) between the atmosphere port 8 and the purge port 7 increases, and this purge It is not possible to properly secure the air, and water may be sucked into the engine.

Accordingly, the present invention has been made in view of the above-mentioned conventional problems, and in view of the above problems, the purging performance of a canister having an inner / outer double cylindrical main body casing due to clogging of a filter on the atmosphere port side by dust or the like has been reduced. It is an object of the present invention to prevent a decrease, a decrease in an adsorbing ability of an evaporative fuel, and the like, and to solve a similar problem caused by accumulation of water in a bottom portion of a main body casing.

[0010]

For this purpose, the invention according to claim 1 has an inner / outer double cylindrical main body casing of an inner cylinder and an outer cylinder disposed on the outer periphery of the inner cylinder. A space between the inner cylinder and the outer cylinder, and a space in the inner cylinder each filled with an adsorbent, each having an adsorbent layer partially connected to each other, and a fuel for the internal combustion engine. A charge port through which the evaporated fuel generated in the system is sucked into the adsorbent, and a barge port through which the evaporated fuel adsorbed by the adsorbent is purged into the intake system of the internal combustion engine are provided so as to communicate with one of the adsorbent layers. In the canister provided with the drain port and the fresh air introduction air port opened to communicate with the other adsorbent layer, a cross-sectional area larger than the cross-sectional area of the inner cylinder is provided at one axial end of the main body casing. Filter housing forming a space portion having A filter for connecting the inside of the filter housing casing to the atmosphere port and the other adsorbent layer, and separating the communication portion between the air port and the other adsorbent layer in the filter housing casing from the communication portion with the other adsorbent layer. The filter is stored at the position.

According to a second aspect of the present invention, a filter which is in series with the filter in the filter housing casing is provided in a space formed between the filter in the filter housing casing and the adsorbent layer in the main body casing. It is characterized by being arranged. The invention according to claim 3 is characterized in that a space portion having a predetermined volume is provided between the filter in the filter housing casing and the filter in the main body casing.

According to a fourth aspect of the present invention, the filter is formed in a flat plate shape, and is housed so that a surface direction thereof extends along a cross section of the filter housing casing. The invention according to claim 5 is characterized in that the filter is formed in a cylindrical shape, and is housed so that the center axis direction of the filter coincides with the center axis direction of the canister.

The invention according to claim 6 is characterized in that the filter housing casing is formed in a substantially semi-cylindrical shape or a substantially cylindrical shape. The invention according to claim 7, wherein a drain port is provided for communicating with the inner bottom portion of the main body casing to discharge water accumulated in the inner bottom portion of the main body casing, and the drain port is connected to the charge port or the charge port. Opening / closing means which is opened / closed in response to the pressure of the inner space portion, wherein the opening / closing means is operated when the pressure exceeds a ventilation resistance value between the atmosphere port and the purge port. I do.

According to an eighth aspect of the present invention, the opening / closing means is
A diaphragm valve device, wherein the diaphragm valve device is fixedly attached to the bottom surface of the main body casing so as to surround the drain port, a diaphragm defining the inside of the device main body in two chambers, and the diaphragm A valve body supported on the peripheral wall of the apparatus main body, and a spring which normally elastically biases the valve body in a direction to close the drain port, and one of the two chambers, in which the drain port is opened Is communicated with the atmosphere through a drain,
The other chamber is communicated with the charge port or a space inside the main body casing communicating with the charge port via a pressure passage. .

The operation of the present invention will be described. In the invention according to claim 1, for example, at the time of refueling, the evaporated fuel introduced from the charge port flows through, for example, the adsorbent layer between the inner cylinder and the outer cylinder, and flows through the adsorbent layer in the inner cylinder. Then, the fuel flows through the adsorbent layer toward the atmosphere port, and the evaporated fuel is adsorbed by the adsorbent in each adsorbent layer.

Such a flow of the evaporated fuel is the same in the case of the evaporated fuel guided to the charge port at the time of non-fuel supply such as when the vehicle is parked or running, and the evaporated fuel is applied to the adsorbent in each adsorbent layer. Adsorbed. In addition, at the time of gas purging from the canister, the air introduced into the filter storage casing from the atmosphere port passes through the filter in the filter storage casing and reaches the adsorbent layer of the inner cylinder, from which the air between the inner cylinder and the outer cylinder is removed. By flowing through the adsorbent layer toward the purge port side, the purge gas reaches the intake system of the internal combustion engine through the purge port so as to accompany the air.

According to the second aspect of the invention, when gas is purged from the canister, air introduced into the filter storage casing from the atmosphere port passes through the filter in the filter storage casing, and further passes through the filter in the main body casing. It reaches the adsorbent layer of the cylinder. In the invention according to claim 3, when gas is purged from the canister, air introduced into the filter storage casing from the atmosphere port passes through the filter in the filter storage casing, and a predetermined volume between the filter and the filter in the main body casing. After passing through the space portion, it further passes through a filter in the main casing to reach the adsorbent layer of the inner cylinder.

In the fourth aspect of the present invention, when gas is purged from the canister, air introduced into the filter storage casing from the atmosphere port passes from one side of the flat filter in the filter storage casing to the other side. Then, it reaches the adsorbent layer of the inner cylinder. In the invention according to claim 5, when gas is purged from the canister, air introduced into the filter storage casing from the atmosphere port passes from the outer peripheral surface side to the inner peripheral surface side of the cylindrical filter in the filter storage casing, and From inside to the adsorbent layer of the inner cylinder.

In the invention according to claim 6, the filter housing casing is formed in a substantially semi-cylindrical shape,
The canister is made compact while the filter housing space is enlarged, and the filter housing casing is formed in a cylindrical shape, so that the filter housing space further increases. In the invention according to claim 7, when the pressure of the charge port or the space in the main body casing communicating with the charge port exceeds the ventilation resistance value between the atmosphere port and the purge port, the opening / closing means is opened to open the drain port. It is opened and the water collected at the bottom of the main casing is discharged.

[0020] In the invention according to claim 8, when the pressure in the charge port or the space in the main body casing communicating with the charge port exceeds the ventilation resistance value between the atmosphere port and the purge port, the valve body of the diaphragm valve device is operated. The drain port is opened by being pulled against the elastic force of the spring. Therefore, the water accumulated in the bottom of the main casing is discharged from the drain port into the apparatus main body, and is drained from the outside through the drain port.

[0021]

According to the first aspect of the present invention, a high collection performance can be obtained by the filter having a large collection area stored in the filter storage casing.
It becomes difficult to be blocked by dust and the like, and it is possible to suppress an increase in pressure loss at the time of purging and to appropriately secure air for purging, thereby improving purging performance, thereby improving the adsorbing capacity of evaporated fuel. Can be.

In addition, since the filter housing casing is integrated with the main body casing, there is no need to provide a pipe or a filter chamber separately from the main body casing as in a configuration in which a separate filter is provided. The cost can be reduced without increasing the pressure, and the pressure loss can be prevented from increasing due to the expansion and contraction of the air opening path such as piping. According to the second or third aspect of the present invention, two filters are arranged in series on the atmosphere port side, or a space having a predetermined volume is formed between the two filters. The homogeneity of the purge air with respect to the adsorbent layer is ensured, and the purge performance can be improved.

In particular, according to the third aspect of the present invention, since a space having a predetermined volume is formed between the two filters, vapor at the time of occurrence of migration temporarily accumulates in this space. Release of vapor into the atmosphere can be temporarily suppressed, which is advantageous in conformity with laws and regulations and also advantageous in terms of gasoline odor problem. According to the fourth aspect of the present invention, by applying a flat filter, it is possible to obtain a high collecting performance while maintaining the canister in a compact shape, and to suppress clogging by dust and the like.

According to the fifth aspect of the present invention, a larger collection area can be secured by applying a cylindrical filter.
According to the invention according to claim 6, by forming the filter storage casing in a substantially semi-cylindrical shape, the filter storage casing can be made compact while the filter storage space is enlarged, and the filter storage casing is formed in a substantially cylindrical shape. Thereby, the filter storage space can be further enlarged.

According to the seventh aspect of the invention, it is possible to prevent water from accumulating at the bottom of the main body casing and increase the ventilation resistance value (purge pressure loss) between the atmosphere port and the purge port.
It is possible to improve the gas purging performance and the adsorbing capacity of the evaporated fuel, and it is also possible to avoid the possibility that water is sucked into the engine. According to the invention according to claim 8, the means for opening and closing the drain port can be easily constituted by the diaphragm valve device.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the attached drawings. FIG. 1A is a plan view showing a configuration of an embodiment of a canister according to the present invention, and FIG. 1B is a longitudinal sectional view thereof, which is a sectional view taken along the line AA in FIG. Based on the above, the structure of an embodiment of the canister of the present invention will be described.

That is, in the drawing, the main body casing 20 of the canister is formed in an inner / outer double cylinder shape of an inner cylinder 21 and an outer cylinder 22, and is made of, for example, a synthetic resin or the like.
In this case, the peripheral wall and the upper wall of the outer cylinder 22 and the peripheral wall and the upper wall of the inner cylinder 21 are integrally formed, and the bottom surfaces of the inner cylinder 21 and the outer cylinder 22 are open. The lower end of the peripheral wall of the inner cylinder 21 is formed shorter than the lower end of the peripheral wall of the outer cylinder 22.
2 hangs down from the bottom opening.

A cover 23 for closing the outer cylinder 22 is fixedly attached to the open bottom of the outer cylinder 22. And the inner cylinder 21
A ring-shaped space portion having an open bottom surface is formed between the inner cylinder and the outer cylinder 22, and a space portion having an open bottom surface is formed in the inner cylinder 21. At the upper end of the space between the outer cylinder 22 and the inner cylinder 21, a first chamber 24 is provided.
A first filter 26 having a circular ring shape is formed between the first filter 26 and the upper wall and is supported by the plurality of support pin portions 25.

At the upper end of the space inside the inner cylinder 21, a second
A second filter 29 is formed between the upper wall of the main body casing 20 and a second filter 29 supported by a plurality of support pins 28. Further, a support plate 30 having a large number of communication holes allowing gas flow is provided at a lower end portion side in the outer cylinder 22, and on the inner surface side of the support plate 30,
The third filter 3 is spaced apart from the lower end of the inner cylinder 21.
1 is provided.

A first adsorbent layer 32 is provided between the first filter 26 and the third filter 31 by filling an adsorbent such as activated carbon. Similarly, the second adsorbent layer 3 is filled between the third filter 31 and the adsorbent such as activated carbon.
3 are provided. Further, a third chamber 34 is formed between the support plate 30 and the cover 23, and in the third chamber 34, a direction in which the first and second adsorbent layers 32 and 33 are compressed. A spring 35 for elastically biasing the support plate 30 is interposed.

On the other hand, a purge port 36 and a charge port 37, which communicate with the first adsorbent layer 32 via the first chamber 24 and the first filter 26, are provided on the upper wall of the main body casing 20. ing. In addition, these purge ports 3
The formation positions of 6 and the charge port 37 will be described later. Here, a filter housing casing 39 is fixedly mounted on the upper part of the main body casing 20 to form a space communicating with the atmosphere port 38 and having a cross-sectional area larger than the cross-sectional area of the inner cylinder 21. I have.

The filter housing casing 39 is formed in a substantially semi-cylindrical shape having an open bottom surface, and the bottom opening portion is formed with a communication hole 4 formed in the upper wall of the main body casing 20.
It is communicated with the second chamber 27 through 0. Further, the upper wall of the filter housing casing 39 is provided with an atmospheric port 38 which rises up for a certain length and then extends in the lateral direction.

Then, the filter storage casing 3
A substantially semicircular flat pre-filter 41 whose surface extends along the cross section of the casing 39 is accommodated in the casing 9. In this case, the pre-filter 41 is disposed at a position separated from the upper wall of the main casing 20 and the upper wall of the filter housing casing 39, respectively.
The chambers 42 and 43 are formed between the upper surface of the upper wall and the lower surface of the upper wall of the filter housing 39, respectively.

The purge port 36 and the charge port 3
7 is formed in the upper wall of the main body casing 20 in a portion remaining after the filter housing casing 39 is attached, and is formed in parallel in the horizontal direction with the position of the atmosphere port 38 interposed therebetween. Next, the operation of the canister of this embodiment will be described. For example, during refueling, the evaporated fuel introduced from the charge port 37 into the first chamber 24 passes through the first filter 26 and flows through the first adsorbent layer 32 to the third chamber 34 side.

That is, the third filter 31 and the support plate 30
After passing through the third chamber 34, the evaporated fuel enters the third chamber 34.
The second adsorbent layer 33 passes through the second and third filters 31 again and enters the second adsorbent layer 33, and flows through the second adsorbent layer 33 toward the second chamber 27. Adsorbent layer 32
Then, the evaporated fuel is adsorbed by the adsorbent in the second adsorbent layer 33.

Such a flow of the evaporated fuel is supplied to the charge port 37 during non-fueling such as when the vehicle is parked or running.
Similarly, the fuel vapor is adsorbed to the adsorbent by the first adsorbent layer 32 and the second adsorbent layer 33. When gas is purged from the canister, the filter housing casing 3 is
The air introduced into the chamber 43 of the ninth embodiment passes through the pre-filter 41 and reaches the chamber 42, from which the second adsorbent layer 3 passes through the communication hole 40, the second chamber 27 and the second filter 29.
2 and then flows through the third chamber 34 through the first adsorbent layer 32 toward the first chamber 24,
The purge gas passes through the first filter 26 and flows to the first chamber 24 along with the air, and the purge gas guided to the first chamber 24 is supplied to the intake system of the internal combustion engine by the purge port 36. Reach.

According to the canister of this embodiment, a filter is provided above the main body casing 20 to form a space communicating with the atmosphere port 38 and having a cross-sectional area larger than the cross-sectional area of the inner cylinder 21. The storage casing 39 is fixedly mounted, and a substantially semicircular pre-filter 41 whose surface extends along the cross section of the casing 39 is stored in the filter storage casing 39, so that the collection area is large. By the pre-filter 41, a high trapping performance can be obtained, and the pre-filter 41 is less likely to be blocked by dust or the like.

At the time of gas purging from the canister, air introduced from the atmosphere port 38 passes through the pre-filter 41 and the second filter 29 and flows to the adsorbent layers 33 and 32. As a result of suppressing the filter 41 from being clogged by dust or the like, it is possible to suppress an increase in pressure loss at the time of purging, it is possible to properly secure air for purging, and it is possible to improve the purging performance. Improvement can be achieved.

Further, since the filter housing casing 39 is provided integrally with the main body casing 20,
Since there is no need to provide a pipe or a filter chamber separately from the main body casing as in a configuration in which a separately provided filter is provided, it is possible to reduce costs without increasing the number of connection portions such as pipes, It is also possible to prevent an increase in pressure loss due to expansion and contraction of an atmosphere opening path such as a pipe.

In particular, according to the above-described embodiment, the pre-filter 41 and the second filter 29 are provided in series on the side of the atmosphere port 38, and a predetermined volume between the pre-filter 41 and the second filter 29 is provided. Since the second chamber 27 is provided, the air introduced from the atmosphere port 38 at the time of gas purging from the canister is diffused by the pre-filter 41, and then the second chamber 2 reaches the second chamber 2 after passing through the pre-filter 41.
7 and passes through a second filter 29 having substantially the same diameter as the second adsorbent layer 33 to reach the second adsorbent 33. The homogeneity of the air is ensured, and the purging performance can be improved.

The pre-filter 41 and the second filter 2
According to the configuration in which the second chamber 27 having a predetermined volume is provided between the second chamber 9 and the vapor 9, the vapor at the time of migration temporarily accumulates in the second chamber 27, and the vapor is released from the atmosphere port 38 into the atmosphere. Is temporarily suppressed, which is advantageous in conformity with laws and regulations, and is also advantageous in terms of gasoline odor problem.

Next, another embodiment of the canister of the present invention will be described with reference to FIG. This embodiment increases the volume of the space in the storage casing of the pre-filter and substantially changes the pre-filter into a cylindrical shape without substantially changing the maximum height of the canister and the height of the atmosphere port, compared to the previous embodiment. The canister is placed vertically, that is, the center axis direction of the canister coincides with the center axis direction of the canister.

That is, the filter housing casing 44 is formed in a substantially semi-cylindrical shape (a shape closer to a circle than the filter housing casing 39 of the embodiment of FIG. 1) with an open bottom surface. The casing 20 communicates with the second chamber 27 via a communication hole 40 formed in the upper wall. An air port 45 extending in the lateral direction is provided on a flat wall of the peripheral wall of the filter housing casing 44.

Then, the filter storage casing 4
4, a cylindrical pre-filter 46 is placed vertically, that is,
The canister is installed so that its central axis direction matches the central axis direction of the canister. In this case, a pre-filter 46 is attached to the outer peripheral portion of each of the cylindrical lower mounting portion 47 protruding from the upper surface of the upper wall of the main body casing 20 and the cylindrical upper mounting portion 48 protruding from the lower surface of the upper wall of the filter housing casing 44. The inner peripheral portions at both ends of are fitted. In this case, the lower mounting portion 47
The communication hole 40 is formed in the upper wall of the main body casing 20 located inside the inside of the pre-filter 46.
0 is opened.

The purge port 49 and the charge port 50 are formed in parallel on the upper wall of the main body casing 20 at the remaining portion after the filter housing casing 44 is attached, at the side of the atmosphere port 45. In each of the above embodiments, the filter housing casings 39, 44 attached to the upper wall of the main body casing 20 are formed in a substantially semi-cylindrical shape, and the flat or cylindrical pre-filters 41, 46 are disposed therein. However, as shown in FIG. 3, the filter housing casing 51 is formed in a substantially cylindrical shape, and inside thereof,
For example, a plate-like and substantially circular pre-filter 52 may be provided.

In this case, a portion of the upper wall of the main body casing 20 corresponding to the upper surface of the inner cylinder 21 is opened, and the inside of the inner cylinder 21 and the inside of the filter housing casing 51 are communicated. or,
An air port 53 is provided at the center of the upper wall of the filter housing 51. Further, the filter storage casing 51
Opposite two positions of the peripheral wall portion are formed with concave groove portions 51A which are concaved inward so as to avoid the purge port 54 and the charge port 55 provided in a portion corresponding to the upper surface of the outer cylinder 22 on the upper wall of the main body casing 20. The purge port 54 and the charge port 5 are formed through the inside of the concave groove 51A.
5 extend upward.

The filter housing casing 51
Inside, a pre-filter 52 whose plane direction extends along the transverse section of the casing 51 is housed. According to this embodiment, the collecting area of the pre-filter 52 can be made larger than that of the embodiment of FIG. 1, and a higher collecting performance can be obtained, and the pre-filter 52 is less likely to be blocked by dust and the like. There is an advantage that it becomes.

Next, still another embodiment of the present invention will be described with reference to FIG. In this embodiment, the main casing 20
In view of the fact that water accumulates in the inner bottom and purge becomes difficult even when the intake negative pressure of the internal combustion engine is introduced into the purge port 54 during purging, a drain port 56 communicating with the inner bottom of the main casing 20 is provided. An opening / closing means for opening / closing the drain port 56 in accordance with the pressure of the charge port 55 or the space in the main body casing (first chamber 24) communicating with the charge port 55 is provided.
Water accumulates in the inner bottom and the atmosphere port 53 and the purge port 5
When the airflow resistance (purge pressure loss) between the four exceeds a predetermined value, the opening / closing means is opened to open the drain port 56, and water collected at the bottom inside the main body casing 20 is discharged to the outside. .

To explain this embodiment more specifically, a diaphragm valve device 57 for opening and closing a drain port 56 communicating with the inner bottom of the cover 22 is provided at the center of the cover 23 at the bottom of the main body casing 20. . The diaphragm valve device 57 includes a device main body 58, a valve body 59, a diaphragm 60, and a spring 61.

The apparatus main body 58 is fixedly mounted on the bottom surface of the cover 23 of the main body casing 20 so as to surround the drain port 56. The valve body 59 includes the diaphragm 6
0 is supported on the peripheral wall of the apparatus main body 58, and is normally elastically urged by a spring 61 in a direction to close the drain port 56. In the apparatus main body 58, two chambers a and b defined by the diaphragm 60 are provided.
One of the chambers a where the drain port 56 opens is communicated with the atmosphere through a drain port 62, and the other chamber b where the spring 61 is provided is a first chamber through a pressure passage 63. 24, the pressure in the first chamber 24 acts.

Here, the pressure in the first chamber 24 is lower than the pressure in the second chamber 27, and the water head pressure ΔP (the water head pressure at which it becomes difficult to introduce air from the atmosphere port 53 to the purge port 54). Before the above, the valve element 5 of the diaphragm valve device 57
9 is opened. The valve opening pressure PD of the valve body 59 is set as follows. PD <ΔP PD> PO where PO is the ventilation resistance between the atmosphere port 53 and the purge port 54 of the main casing 20. PD> PT where PT is the charge pressure from the fuel tank to which the charge port 55 communicates. When water accumulates at the bottom of the inner wall 20 and reaches the valve opening pressure, the valve body 59 is opened, and the drain port 56 is opened.
Is released. Due to the opening of the drain port 56, water collected at the bottom of the main body casing 20 flows out into the chamber a,
The water is discharged from the chamber a through the drain port 62 to the outside.

Note that, as in the above embodiment, the first chamber 2
In the configuration in which the internal pressure is guided to the chamber b of the diaphragm valve device 57, pulsation due to the operation of the purge control valve interposed in the purge port 54 is easily received. Therefore, as shown by a dashed line in the figure, it is preferable that the charge port 55 and the chamber b of the diaphragm valve device 57 communicate with each other so as to be less affected by the pulsation caused by the operation of the purge control valve.

According to this embodiment, it is possible to prevent water from accumulating in the bottom of the main body casing 20 and increase the ventilation resistance (purge pressure loss) between the atmosphere port 53 and the purge port 54, thereby improving the gas purge performance and evaporating. The ability to adsorb fuel can be improved, and the risk of water being drawn into the engine can also be avoided.

[Brief description of the drawings]

FIG. 1A is a plan view showing a configuration of an embodiment of a canister according to the present invention, and FIG. 1B is a longitudinal sectional view thereof, taken along the line AA in FIG. 1A.

FIG. 2A is a plan view showing the configuration of another embodiment of the canister according to the present invention, and FIG. 2B is a longitudinal sectional view thereof, and is a sectional view taken along line BB in FIG. 2A.

FIG. 3 (A) is a plan view showing the configuration of still another embodiment of the canister according to the present invention, and FIG. 3 (B) is a longitudinal sectional view thereof, taken along the line CC in FIG. 3 (A). Figure

FIG. 4 is a longitudinal sectional view showing a configuration of still another embodiment.

5 (A) is a plan view showing another configuration of a conventional canister, and FIG. 5 (B) is a longitudinal sectional view thereof, and is a sectional view taken along the line DD in FIG. 5 (A).

FIG. 6 is a schematic diagram of another conventional example.

[Explanation of symbols]

 Reference Signs List 20 body casing 21 inner cylinder 22 outer cylinder 36 purge port 37 charge port 38 atmosphere port 39 filter storage casing 41 pre-filter 44 filter storage casing 45 atmosphere port 46 pre-filter 49 purge port 50 charge port 51 filter storage casing 52 pre-filter 53 atmosphere Port 54 Purge port 55 Charge port 56 Drain port 57 Diaphragm valve device

Claims (8)

[Claims] 1. An inner / outer double cylinder-shaped main body casing comprising an inner cylinder and an outer cylinder disposed on an outer periphery of the inner cylinder, wherein a space between the inner cylinder and the outer cylinder and an inner cylinder are provided. A charge port formed by filling the space in the cylinder with the adsorbent and having adsorbent layers each partially communicating with each other, and allowing the adsorbent to inhale evaporated fuel generated in the fuel system of the internal combustion engine into the adsorbent; A barge port for purging evaporated fuel adsorbed by the adsorbent is provided in the intake system of the internal combustion engine in communication with one of the adsorbent layers, and an air port for drain and fresh air introduction to the atmosphere is provided. In the canister provided in communication with the other adsorbent layer, a filter housing casing is provided at one axial end of the main body casing, the filter housing casing forming a space having a cross-sectional area larger than the cross-sectional area of the inner cylinder. Inside the casing The filter is housed at a position separating the communication part with the atmosphere port and the communication part with the other adsorbent layer in the filter storage casing, by communicating with the air port and the other adsorbent layer. Canister. 2. A filter which is arranged in series with the filter in the filter storage casing in a space formed between the filter in the filter storage casing and the adsorbent layer in the main body casing. Claim 1
The canister as described. 3. The canister according to claim 2, wherein a space having a predetermined volume is provided between the filter inside the filter housing casing and the filter inside the main body casing. 4. The filter according to claim 1, wherein the filter is formed in a flat plate shape, and is housed so that a surface direction thereof extends along a cross section of the filter housing casing. The canister as described. 5. The filter according to claim 1, wherein the filter is formed in a cylindrical shape, and is housed such that a center axis direction of the filter coincides with a center axis direction of the canister. The canister as described. 6. The canister according to claim 1, wherein the filter housing casing is formed in a substantially semi-cylindrical shape or a substantially cylindrical shape. 7. A main body casing inner space which communicates with the main body casing inner bottom and discharges water accumulated in the main body casing inner bottom, and connects the drain port to the charge port or the charge port. An opening / closing means that is opened / closed in response to the pressure of the air, wherein the opening / closing means is opened when the pressure exceeds a ventilation resistance value between the atmosphere port and the purge port. 7. The canister according to any one of 1 to 6. 8. The opening / closing means comprises a diaphragm valve device, wherein the diaphragm valve device is fixedly mounted on a bottom surface of a main body casing so as to surround a periphery of the drain port, and has two chambers inside the device main body. The two chambers, comprising: a diaphragm defined by the diaphragm; a valve body supported on the peripheral wall of the apparatus main body by the diaphragm; and a spring that normally elastically biases the valve body in a direction to close the drain port. One of the chambers in which the drain port is open is communicated with the atmosphere via a drain port, and the other chamber is communicated with the charge port or a space inside the main body casing communicating with the charge port via a pressure passage. The canister according to claim 7, wherein: