Patent Publication Number: US-2023151783-A1

Title: Canister

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of Japanese Patent Application No. 2021-185792 filed on Nov. 15, 2021 with the Japan Patent Office, the entire disclosure of which is incorporated herein by reference. 
     BACKGROUND 
     The present disclosure relates to a canister for adsorbing fuel vapor generated in a fuel tank. 
     As disclosed in Japanese Unexamined Patent Application Publication No. 2018-96254, known is a technique of providing, in a chamber of a canister, a plurality of rod-shaped portions extending substantially parallel to a flow direction of fuel vapor in order to reduce the ventilation resistance. 
     SUMMARY 
     In recent years, however, there has been a tendency to decrease engine displacement of a vehicle for better fuel efficiency, and this leads to decrease in purge air for removing the fuel accumulated in the canister. In order to satisfactorily remove the fuel accumulated in the canister with less purge air, the ventilation resistance of the canister needs to be reduced. 
     Moreover, in recent years, performance level required of the canister has been further raised for environmental measures, and in general, the performance of the canister is improved with the improvement in L/D. L means the length of the chamber of the canister in a gas flow direction, and D means an equivalent diameter of a cross section of the chamber perpendicular to the gas flow direction. However, the improvement in L/D causes increase in the ventilation resistance of the canister, resulting in greater pressure loss in the canister. 
     In one aspect of the present disclosure, it is desirable to reduce the ventilation resistance of a canister. 
     One aspect of the present disclosure is a canister configured to be mounted in a vehicle with an engine. The canister comprises at least one chamber, an inflow port, an atmosphere port, an outflow port, and a plurality of rod-shaped portions. In the at least one chamber, an adsorbent to adsorb fuel vapor is arranged. The inflow port is configured to allow the fuel vapor to flow into the at least one chamber from a fuel tank of the vehicle. The atmosphere port is configured to allow atmospheric air to flow into the at least one chamber from outside of the vehicle. The outflow port is configured to allow the fuel vapor adsorbed on the adsorbent to flow out toward the engine by means of the atmospheric air flowing in from the atmosphere port. The plurality of rod-shaped portions is a plurality of elongated portions arranged in an object chamber, which is any of the at least one chamber. The adsorbent arranged in the object chamber is formed as a plurality of granular bodies. At least a part of the plurality of rod-shaped portions has, on an outer peripheral surface thereof, at least one recess formed. 
     In the above-described configuration, gaps are formed, in the object chamber, between the at least one recess formed on the rod-shaped portion and the adsorbent as the plurality of granular bodies. This enables reduction of the ventilation resistance of the canister. 
     In one aspect of the present disclosure, the plurality of rod-shaped portions may extend substantially parallel to a gas flow direction in the object chamber. 
     This configuration encourages the gaps between the at least one recess on the rod-shaped portion and the adsorbent to be formed along the gas flow direction, in the object chamber. Accordingly, the ventilation resistance of the canister can be further reduced. 
     In one aspect of the present disclosure, the at least one recess may be a groove-shaped portion extending substantially parallel to an extending direction of each rod-shaped portion of the plurality of rod-shaped portions on which the at least one recess is arranged. 
     This configuration encourages the gaps between the at least one recess on the rod-shaped portion and the adsorbent to be formed along the extending direction of the rod-shaped portion, in the object chamber. Accordingly, the ventilation resistance of the canister can be further reduced. 
     In one aspect of the present disclosure, each granular body of the plurality of granular bodies as the adsorbent arranged in the object chamber may be substantially cylindrically shaped. A width of the at least one recess may be smaller than a diameter of a cross section of each granular body of the plurality of granular bodies perpendicular to an extending direction thereof. 
     This configuration makes it possible to inhibit the granular bodies as the adsorbent from entering the inside of the at least one recess formed on the rod-shaped portion to thereby facilitate formation of the gaps between the at least one recess on the rod-shaped portion and the adsorbent. Accordingly, the ventilation resistance of the canister can be further reduced. 
     In one aspect of the present disclosure, the canister may further comprise a coupler to couple each rod-shaped portion of the plurality of rod-shaped portions to another rod-shaped portion of the plurality of rod-shaped portions. The coupler may be arranged at an end of each rod-shaped portion of the plurality of rod-shaped portions. 
     This configuration facilitates manufacture of the rod-shaped portions and the couplers, and also enables reduction of workload in arranging the adsorbent in the object chamber. 
     In one aspect of the present disclosure, the canister may further comprise a coupler to couple each rod-shaped portion of the plurality of rod-shaped portions to another rod-shaped portion of the plurality of rod-shaped portions. The coupler may be arranged at a position apart from ends of each rod-shaped portion of the plurality of rod-shaped portions. 
     This configuration makes it possible to avoid the couplers from being arranged at ends of the object chamber, to thereby inhibit occurrence of non-uniform flow of the atmospheric air and the fuel vapor at the ends of the object chamber. Accordingly, it is possible to encourage the flow of the atmospheric air and the fuel vapor to be more uniform, in the object chamber as a whole. 
     In one aspect of the present disclosure, the plurality of rod-shaped portions may comprise at least one particular rod-shaped portion. The at least one particular rod-shaped portion may have the at least one recess arranged thereon, and may comprise at least two segments arranged along an extending direction of the at least one particular rod-shaped portion. The at least two segments adjacent to each other may differ in a shape of a cross section thereof perpendicular to the extending direction of the at least one particular rod-shaped portion. 
     This configuration makes it possible to adjust the ventilation resistance of the object chamber more flexibly. 
     In one aspect of the present disclosure, the plurality of rod-shaped portions may comprise rod-shaped portions of at least two types. The rod-shaped portions of at least two types may differ in a shape of a cross section thereof perpendicular to an extending direction of each rod-shaped portion. 
     This configuration makes it possible to adjust the ventilation resistance of the object chamber more flexibly. 
     In one aspect of the present disclosure, at least a part of the plurality of rod-shaped portions may have, on an outer peripheral surface thereof, a plurality of recesses formed. In one aspect of the present disclosure, the at least one recess may be formed on each rod-shaped portion of the plurality of rod-shaped portions. 
     These configurations make it possible to adjust the ventilation resistance of the object chamber more flexibly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Example embodiments of the present disclosure will be described below with reference to the accompanying drawings, in which: 
         FIG.  1    is a sectional view of a canister of a first embodiment as viewed from its side; 
         FIG.  2    is an explanatory diagram of an adsorbent of the first embodiment, formed as a pellet of activated carbon; 
         FIG.  3    is a front view of a grid member of the first embodiment; 
         FIG.  4    is a side view of the grid member of the first embodiment; 
         FIG.  5    is a bottom view of the grid member of the first embodiment as viewed from a first end side; 
         FIG.  6    is a sectional view of a rod-shaped portion of the first embodiment, perpendicular to its extending direction; 
         FIG.  7    is a sectional view of a rod-shaped portion of the first embodiment, perpendicular to its extending direction; 
         FIG.  8    is a sectional view of a rod-shaped portion of the first embodiment, perpendicular to its extending direction; 
         FIG.  9    is a sectional view of a rod-shaped portion of the first embodiment, perpendicular to its extending direction; 
         FIG.  10    is a sectional view of a rod-shaped portion of the first embodiment, perpendicular to its extending direction; 
         FIG.  11    is a sectional view of a rod-shaped portion of the first embodiment, perpendicular to its extending direction; 
         FIG.  12    is a front view of a grid member of a second embodiment; 
         FIG.  13    is a side view of the grid member of the second embodiment; and 
         FIG.  14    is a bottom view of the grid member of the second embodiment as viewed from a first end side. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Embodiments of the present disclosure are not limited to the embodiments below, and may take various forms as long as they belong to the technical scope of the present disclosure. 
     First Embodiment 
     1. Configuration of Canister 
     A canister  1  of a first embodiment (see  FIG.  1   ) is mounted in a vehicle. The vehicle in which the canister  1  is mounted will be hereinafter referred to as the vehicle concerned. The canister  1  comprises a container  10  of synthetic resin. The container  10  comprises a first chamber  20 , a second chamber  30 , and a third chamber  40 . Arranged respectively in the first chamber  20 , the second chamber  30 , and the third chamber  40  are adsorbents  60 ,  61 , and  62  for adsorbing fuel vapor. The number of chambers in the canister  1  may be, for example, two or less, or four or more. 
     The adsorbent  60  in the first chamber  20  may be formed as, for example, powdered activated carbon, or may be formed as pellets to be described below. 
     The adsorbent  61  in the second chamber  30  is formed as pellets, which are granular activated carbon (see  FIG.  2   ). As an example, each pellet has a substantially cylindrical shape, and the diameter of a cross section of the pellet perpendicular to its extending direction (i.e., its axial direction) is hereinafter referred to as R. However, the shape of the pellet is not limited to a cylindrical shape, and may be a spheroidal shape, for example. In the case where the pellet has a spheroidal shape, the diameter of the pellet may be set to R. Alternatively, the adsorbent  61  may be formed as a granular adsorbent other than the pellets. 
     As an example, the adsorbent  62  in the third chamber  40  is formed as a honeycomb carbon block with a ventilation resistance lower than those of the powdered activated carbon and the pellets. The honeycomb carbon block comprises a side wall having a cylindrical shape, and is arranged in the third chamber  40  so as to extend in a gas flow direction. Provided inside the side wall are a plurality of flow paths passing through the honeycomb carbon block in its extending direction. 
     The adsorbent  62  in the third chamber  40  may be formed of the powdered activated carbon, or may be formed of the pellets. Alternatively, the adsorbents  60 ,  61 , and  62  respectively arranged in the first chamber  20 , the second chamber  30 , and the third chamber  40  may be formed of a material other than the activated carbon. 
     Provided at an end of the container  10  are an inflow port  11 , an outflow port  12 , and an atmosphere port  13 . The inflow port  11  and the outflow port  12  allow for communication between the inside of the first chamber  20  and the outside of the container  10 . The atmosphere port  13  allows for communication between the inside of the third chamber  40  and the outside of the container  10 . 
     Hereinafter, a side of the container  10  of the canister  1  where the inflow port  11 , the outflow port  12 , and the atmosphere port  13  are arranged is referred to as a port side. The container  10  includes an opening on a side opposite to the port side. The opening is closed by a lid member  14 . Hereinafter, the side opposite to the port side (i.e., a side where the lid member  14  is arranged) is referred to as a lid side. 
     The inflow port  11  is connected to a fuel tank for an engine of the vehicle concerned. The fuel vapor generated in the fuel tank flows into the canister  1  via the inflow port  11 , and is adsorbed on the adsorbents  60 ,  61 , and  62  in the respective chambers. In this way, the fuel is accumulated inside the canister  1 . 
     The outflow port  12  is connected to an intake pipe of the engine of the vehicle concerned, and the atmosphere port  13  communicates with the outside of the vehicle concerned. The negative intake air pressure of the engine causes atmospheric air (i.e., purge air) to flow into the canister  1  via the atmosphere port  13 . Such inflow of the purge air causes the fuel adsorbed on the adsorbents  60 ,  61 , and  62  to be desorbed, and the desorbed fuel flows out together with the purge air from the outflow port  12  toward the intake pipe. In this way, a purging to remove the fuel adsorbed on the adsorbents  60 ,  61 , and  62  is carried out, and the adsorbents  60 ,  61 , and  62  are recovered. 
     In other words, the fuel vapor flowing in from the inflow port  11 , the fuel vapor flowing out from the outflow port  12  during the purging, and the purge air flowing in from the atmosphere port  13  during the purging, flow in the chambers  20 ,  30 , and  40  along a direction in which an end on the port side and an end on the lid side face each other. 
     As an example, the first chamber  20  has a substantially rectangular parallelepiped shape, and its port side end is connected to the inflow port  11  and to the outflow port  12 . There are provided filters  21  and  22 , respectively, on the port side end and a lid side end of the first chamber  20 , and the adsorbent  60  is arranged between the filters  21  and  22 . 
     The first chamber  20  communicates, on its lid side end, with a communicating passage  15 . The communicating passage  15  is arranged along the lid member  14 , thus interconnecting the first chamber  20  and the second chamber  30 . There is provided a porous plate  23  with permeability between the filter  22  on the lid side of the first chamber  20  and the communicating passage  15 , and a coil spring  16  is provided between the porous plate  23  and the lid member  14 . The coil spring  16  presses the porous plate  23  toward the port side. This allows fluid to flow to and fro between the first chamber  20  and the second chamber  30  via the communicating passage  15 , in the inside of the canister  1 . 
     The second chamber  30  and the third chamber  40  are adjacent to the first chamber  20 , and each have an elongated shape extending from the lid side to the port side. The second chamber  30  and the third chamber  40  are arranged from the lid side to the port side, with their ends adjacent to each other. The second chamber  30  and the third chamber  40  are separated by a partition member  18  with permeability having a plate shape. This allows fluid to pass through the partition member  18  and flow to and fro between the inner space of the second chamber  30  and the inner space of the third chamber  40 . 
     There is provided a filter  31  on a lid side end of the second chamber  30 , and the adsorbent  61  is arranged between the filter  31  and the partition member  18 . Further, there is provided a filter  41  on a port side end of the third chamber  40 , and the adsorbent  62  is arranged between the filter  41  and the partition member  18 . 
     There is provided a porous plate  32  with permeability between the filter  31  on the lid side of the second chamber  30  and the communicating passage  15 , and a coil spring  17  is provided between the porous plate  32  and the lid member  14 . The coil spring  17  presses the porous plate  32  toward the port side. The port side end of the third chamber  40  is connected to the atmosphere port  13 . 
     2. Grid Member 
     In the first embodiment, as an example, the second chamber  30  is configured as an object chamber, and a grid member  5  is provided in the second chamber  30  (see  FIG.  1   ). As an example, the grid member  5  is formed of a resin into one piece, and comprises a plurality of rod-shaped portions  50 , first and second couplers  52  and  53 , and first and second spacers  54  and  55  (see  FIGS.  3  through  5   ). The grid member  5  may be formed of a material other than the resin. 
     The rod-shaped portions  50  are elongated portions extending so as to be substantially parallel to each other with spaces therebetween, and are arranged so as to form, as an example, a first row  5 C, a second row  5 D, and a third row  5 E. The rod-shaped portions  50  have the lengths substantially identical to each other, and are arranged throughout the second chamber  30  so as to extend substantially parallel to the gas flow direction. A first end  5 A of each rod-shaped portion  50  is located on or around a port side end of the second chamber  30 , and a second end  5 B is located on or around the lid side end of the second chamber  30 . 
     The number of the rows of the rod-shaped portions  50  and the number of the rod-shaped portions  50  arranged in each row may be determined as appropriate according to the size of the chamber in which the grid member  5  is arranged. Alternatively, a configuration may be employed in which the first end  5 A of each rod-shaped portion  50  is located on the lid side end of the second chamber  30  and the second end  5 B is located on the port side end. 
     The outer peripheral surface of each rod-shaped portion  50  may extend parallel to its extending direction so that its thickness (i.e., the area of its cross section) is constant, or the outer peripheral surface may be inclined with respect to the extending direction. More specifically, the outer peripheral surface of each rod-shaped portion  50  may be inclined with respect to its extending direction so that it becomes thinner with increasing distance from the first coupler  52  or from the second coupler  53  toward the corresponding end. 
     The first and second couplers  52  and  53  are each arranged substantially in the middle in the extending direction of the corresponding rod-shaped portion  50 , and each couple the corresponding rod-shaped portion  50  to at least one of the other rod-shaped portions  50 . As an example, the first and second couplers  52  and  53  each couple the corresponding rod-shaped portions  50  in the first row  5 C or the third row  5 E to the nearest rod-shaped portion  50  in the second row  5 D. Also, the first and second couplers  52  and  53  each couple the corresponding rod-shaped portion  50  in the second row  5 D to another one or other two of the rod-shaped portions  50  in the second row  5 D, adjacent to such corresponding rod-shaped portion  50 . 
     The first coupler  52  is positioned on a side of the first end  5 A with respect to the center of the rod-shaped portion  50  in its extending direction, and the second coupler  53  is positioned on a side of the second end  5 B with respect to such center. The positions of the first and second couplers  52  and  53  are not limited to the ones described above, and are determined as appropriate. However, it is preferred that the first and second couplers  52  and  53  be arranged at positions apart from the ends of the rod-shaped portions  50  (i.e., from the ends of the second chamber  30 ). 
     The first spacer  54  is a portion for spacing the rod-shaped portions  50  from the inner wall of the second chamber  30 , and is arranged substantially in the middle in the extending direction of the rod-shaped portion  50  located on each end of the first and third rows  5 C and  5 E. The first spacer  54  protrudes toward the inner wall of the second chamber  30  from the outer peripheral surface of such rod-shaped portion  50 , and abuts the inner wall of the second chamber  30 . 
     The second spacer  55  is a portion for spacing the rod-shaped portions  50  from the inner wall of the second chamber  30 , and is arranged on the first ends  5 A of the two rod-shaped portions  50  located in the middle of each of the first and third rows  5 C and  5 E. The second spacer  55  comprises a first part abutting the inner wall of the second chamber  30 , and also comprises a second part connecting the first part to the respective outer peripheral surfaces of such two rod-shaped portions  50 . 
     The first chamber  20  or the third chamber  40  may be configured as the object chamber in which the grid member  5  is arranged, or two or more of the first chamber  20 , the second chamber  30 , and the third chamber  40  may be configured as the object chambers. In the object chamber, a granular adsorbent, such as pellets, is arranged. 
     3. Details of Rod-Shaped Portion 
     Each rod-shaped portion  50  in the grid member  5  has at least one recess  51  formed on its outer peripheral surface (see  FIGS.  3  through  5   ). As an example, the at least one recess  51  is a groove-shaped portion extending substantially parallel to the extending direction of the rod-shaped portion  50  from the first end  5 A or its vicinity to the second end  5 B or its vicinity. For the grid member  5 , the rod-shaped portions  50  having various shapes may be used. 
     Specifically, for example, each rod-shaped portion  50  may be formed such that its cross section perpendicular to its extending direction (hereinafter simply referred to as the cross section) is substantially circular, and also a plurality of the recesses  51  may be formed on the outer peripheral surface of the rod-shaped portion  50  so as to be arranged with substantially equal spacing along the periphery of the cross section (see  FIG.  6   ). 
     Alternatively, for example, each rod-shaped portion  50  may be formed such that its cross section is substantially square, and also the recesses  51  may be formed in respective positions, on the outer peripheral surface of the rod-shaped portion  50 , corresponding to four corners of the cross section (see  FIG.  7   ). 
     Alternatively, for example, each rod-shaped portion  50  may be formed such that its cross section is substantially rectangular, and also the recesses  51  may be formed on the outer peripheral surface of the rod-shaped portion  50  so as to be arranged with substantially equal spacing along the periphery of the cross section (see  FIG.  8   ). 
     Alternatively, for example, each rod-shaped portion  50  may be formed such that its cross section is X-shaped, and also the recesses  51  may be formed on the outer peripheral surface of the rod-shaped portion  50  so as to be arranged with substantially equal spacing along the periphery of the cross section (see  FIG.  9   ). 
     Alternatively, for example, each rod-shaped portion  50  may be formed such that its cross section has a curved rectangular shape, and also the recesses  51  may be formed on the outer peripheral surface of the rod-shaped portion  50  so as to be arranged with substantially equal spacing along the periphery of the cross section (see  FIG.  10   ). 
     The width W of the recess  51  is smaller than the diameter R of the cross section of the adsorbent  61  formed as cylindrically-shaped pellets. Obviously, the width W of the recess  51  can be determined as appropriate without being limited to the above, and may be greater than or equal to the diameter R of the cross section of the adsorbent  61 . The recesses  51  formed in each rod-shaped portion  50  may be one in number. 
     4. Modified Example of Rod-Shaped Portion 
     Besides, for example, the grid member  5  may be configured with the rod-shaped portions  50  of two or more types differing in the shape of the cross section (i.e., differing in the number, position, size, and/or shape of the recesses  51 ). Specifically, for example, a configuration may be employed in which first to third rod-shaped portions of different types are provided and the first to third rod-shaped portions are respectively arranged in the first to third rows  5 C to  5 E (see  FIGS.  4  and  5   ). 
     The at least one recess  51  may be formed on all of the first to third rod-shaped portions, or no recess  51  may be formed on one or two of the first to third rod-shaped portions. The cross section of the rod-shaped portion  50  on which the recess  51  is not formed may be circular, as an example (see  FIG.  11   ). The first to third rod-shaped portions may each have any of the cross sections illustrated in  FIGS.  6  through  10   . The rod-shaped portions of two or more types differing in the shape of the cross section may be arranged in the same row. 
     At least a part of the rod-shaped portions  50  may be configured as a particular rod-shaped portion. The particular rod-shaped portion comprises two or more segments arranged along the extending direction of the particular rod-shaped portion. The segments adjacent to each other differ in the shape of the cross section. The shapes of the cross sections of the respective segments of the particular rod-shaped portion may be different from each other. Specifically, for example, the particular rod-shaped portion may be configured such that it has a boundary at a portion where the first coupler  52  or the second coupler  53  is arranged, and such that a first segment  50 A is arranged on a side of the first end  5 A and a second segment  50 B is arranged on a side of the second end  5 B, with respect to the boundary (see  FIGS.  3  and  4   ). Obviously, the particular rod-shaped portion may be configured such that the boundary is arranged at a position different from where the first coupler  52  or the second coupler  53  is arranged. 
     The at least one recess  51  may be formed on both of the first and second segments  50 A and SOB, or no recess  51  may be formed on one of the first and second segments  50 A and SOB. Further, the first and second segments  50 A and SOB on which the at least one recess  51  is formed may each have any of the cross sections illustrated in  FIGS.  6  through  10   . 
     Alternatively, the grid member  5  may be configured with at least one particular rod-shaped portion and with the at least one rod-shaped portion  50  whose cross sectional shape is substantially identical from the first end  5 A through the second end  5 B (hereinafter referred to as a regular rod-shaped portion). In this case, the grid member  5  may comprise the particular rod-shaped portions of two or more types differing in the shape of the cross section in at least one segment, or may comprise the regular rod-shaped portions of two or more types differing in the shape of the cross section. 
     As described above, the case is assumed in which the outer peripheral surface of each rod-shaped portion  50  is inclined with respect to the extending direction and the thickness of each rod-shaped portion  50  is not constant. In this case, the respective cross sections of the rod-shaped portion  50  in its different positions in the extending direction are substantially identical in the shape but different in the size (i.e., the respective cross sections are similar to each other). It is to be appreciated that such cross sections do not correspond to the above-described cross sections “differing in the shape”. 
     Second Embodiment 
     5. Grid Member 
     Next, the canister  1  of a second embodiment will be described. The canister  1  of the second embodiment is different from that of the first embodiment in terms of the configuration of a grid member  7 . The canister  1  of the second embodiment will be described below focusing on differences from that of the first embodiment. 
     Similarly to the first embodiment, the grid member  7  is formed of a resin into one piece, as an example, and comprises a plurality of rod-shaped portions  70  and a coupler  72  (see  FIGS.  12  through  14   ). The grid member  7  may be formed of a material other than the resin. 
     The plurality of rod-shaped portions  70  has a configuration as in the first embodiment, and is arranged in a chamber of the canister  1  in a manner similar to the first embodiment. The rod-shaped portions  70  are each provided with at least one recess  71  in a manner similar to the first embodiment, and the shape of the cross section of each rod-shaped portion  70  may be determined similarly to the first embodiment. 
     On the other hand, the grid member  7  of the second embodiment differs in terms of a configuration of the coupler  72  from the corresponding one in the first embodiment. Specifically, the coupler  72  is arranged on a first end  7 A of each rod-shaped portion  70 , and couples the rod-shaped portion  70  to at least one of the other rod-shaped portions  70 . The coupler  72  may be arranged on a second end  7 B of each rod-shaped portion  70 . 
     In the grid member  7  of the second embodiment too, a spacer (not shown) for spacing the rod-shaped portions  70  from the inner wall of the second chamber  30  may be provided in a manner similar to the first embodiment. 
     6. Effects 
     (1) In the above-described embodiments, gaps are formed, in the second chamber  30  as the object chamber, between the recesses formed on the rod-shaped portions and the adsorbent  61  as the pellets. This enables reduction of the ventilation resistance of the canister  1 . Accordingly, L/D of the canister  1  can be increased while inhibiting increase in the pressure loss. 
     In the above-described embodiments, to reduce the ventilation resistance, the honeycomb carbon block, as an example, is used as the adsorbent  62  for the third chamber  40 . However, the honeycomb carbon block requires higher cost than the powdered activated carbon, the pellets, or the like. To cope with this, the grid member  5  or  7  is arranged in the second chamber  30  to reduce the ventilation resistance of the second chamber  30 , and this enables downsizing of the honeycomb carbon block, thus reducing the cost for the canister  1 . 
     (2) The rod-shaped portions  50  and  70  extend substantially parallel to the gas flow direction in the second chamber  30 . This encourages the gaps between the recesses on the rod-shaped portions and the adsorbent  61  to be formed along the gas flow direction, in the second chamber  30 . Accordingly, the ventilation resistance of the canister  1  can be further reduced. 
     (3) The recesses  51  and  71  are groove-shaped portions extending substantially parallel to the extending direction of the rod-shaped portions  50  and  70 , respectively. This encourages the gaps between the recesses  51  and the adsorbent  61 , and between the recesses  71  and the adsorbent  61 , to be formed along the extending direction of the rod-shaped portions  50  and  70 , respectively, in the second chamber  30 . Accordingly, the ventilation resistance of the canister  1  can be further reduced. 
     (4) The width W of the recesses  51  and  71  is smaller than the diameter R of the cross section of each pellet as the adsorbent  61 . This makes it possible to inhibit the pellets from entering the inside of the recesses  51  and  71  to thereby facilitate formation of the gaps between the recesses and the pellets. Accordingly, the ventilation resistance of the canister  1  can be further reduced. 
     (5) The first and second couplers  52  and  53  in the first embodiment are each arranged substantially in the middle of the rod-shaped portions  50 . This makes it possible to inhibit occurrence of non-uniform flow of the atmospheric air and the fuel vapor at the ends of the second chamber  30 . Accordingly, it is possible to encourage the flow of the atmospheric air and the fuel vapor to be more uniform, in the second chamber  30  as a whole. 
     (6) The coupler  72  in the second embodiment is arranged at the ends of the rod-shaped portions  70 . Accordingly, in a case, for example, where the grid member  7  is formed as an integrated member by injection molding or other method, manufacture of the grid member  7  is facilitated. 
     In the process of manufacturing the canister  1 , it is possible to arrange the grid member  7  in the second chamber  30  via the opening of the container  10  such that the coupler  72  is positioned on the port side, and subsequently, to arrange the adsorbent  61  in the second chamber  30  via the opening. Accordingly, workload in arranging the adsorbent  61  in the second chamber  30  can be reduced. 
     (7) The grid members  5  and  7  may each be configured respectively with the rod-shaped portions  50  and  70  of two or more types differing in the shape of the cross section, and also may comprise at least one particular rod-shaped portion. Accordingly, the ventilation resistance of the object chamber can be adjusted more flexibly. 
     7. Other Embodiments 
     (1) In the above-described embodiments, the grid members  5  and  7  may be arranged, respectively, such that the rod-shaped portions  50  and  70  extend in a direction different from the gas flow direction (e.g., in a direction substantially perpendicular to the gas flow direction). Alternatively, the rod-shaped portions  50  of the grid member  5  and the rod-shaped portions  70  of the grid member  7  may each have a bent shape, may have different lengths, and may extend in different directions. 
     (2) The recesses  51  and  71  respectively formed on the rod-shaped portions  50  and  70  may be formed as groove-shaped portions extending in a direction different from the extending direction of the rod-shaped portions  50  and  70 , respectively. Specifically, the recesses  51  and  71  may extend, for example, in a circumferential direction of the cross section of the rod-shaped portions  50  and  70 , respectively, or may extend in a spiral manner. Alternatively, the recesses  51  and  71  are not limited to the groove-shaped portions and, for example, may be formed on dot-shaped areas on the outer peripheral surfaces of the rod-shaped portions  50  and  70 , respectively. 
     (3) Two or more functions of a single element in the above-described embodiments may be performed by two or more elements, and a single function of a single element may be performed by two or more elements. Two or more functions performed by two or more elements may be performed by a single element, and a single function performed by two or more elements may be performed by a single element. Part of the configuration in the above-described embodiments may be omitted. At least a part of the configuration in the above-described embodiments may be added to or replace another configuration in the above-described embodiments.