Patent Publication Number: US-9422894-B2

Title: Evaporation fuel processing device

Description:
BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     The present invention relates to an evaporation fuel processing device. 
     (2) Description of Related Art 
     Conventionally, in order to prevent evaporation fuel from being discharged to the atmosphere from a fuel tank and the like of a vehicle, an evaporation fuel processing device (hereinafter also referred to as a canister) which temporarily adsorbs fuel components in the evaporation fuel has been used. 
     As such a canister, a canister  101  as shown in  FIG. 6  is known (e.g., refer to JP-A-2002-235610), which includes: a case  105  formed with a tank port  102 , a purge port  103 , and an atmospheric air port  104 ; a main chamber  106  communicating with the tank port  102  and the purge port  103 , and an auxiliary chamber  107  communicating with the atmospheric air port  104 , the main chamber  106  and the auxiliary chamber  107  formed in the case  105  and communicating with each other in a part on an opposite side of the atmospheric air port  104 ; a first adsorbent layer  111  filled with activated carbon and formed in the main chamber  106 ; a second adsorbent layer  112 , a third adsorbent layer  113 , and a fourth adsorbent layer  114  filled with the activated carbon and serially disposed in the auxiliary chamber  107 ; and partition plates  121  and  122  disposed between the second adsorbent layer  112  and the third adsorbent layer  113 , and between the third adsorbent layer  113  and the fourth adsorbent layer  114 , respectively. 
     In this canister  101 , a volume of the fourth adsorbent layer  114  is set smaller than that of the other adsorbent layers  111 ,  112 , and  113  so as to reduce blow-by of the evaporation fuel to the atmosphere. 
     SUMMARY OF THE INVENTION 
     In the canister  101  of the related art, volumes between the second adsorbent layer  112  and the third adsorbent layer  113 , and between the third adsorbent layer  113  and the fourth adsorbent layer  114  are small. For this reason, during purging, when gas temperature decreases due to desorption of fuel components from the activated carbon in the fourth adsorbent layer  114  or the third adsorbent layer  113 , the reduced gas temperature hardly rises in spaces at the partition plates  122  and  121 , and the gas soon flows into the adsorbent layers  113  and  112  on the tank port  102  side. Accordingly, the desorption performance in these adsorbent layers  113  and  112  is degraded, which may result in insufficient desorption of the fuel components. 
     As a result, a residual amount of the fuel components in the activated carbon after purging becomes large, which may cause blow-by to the atmosphere. 
     In view of this, the present invention has an object to provide an evaporation fuel processing device which reduces the residual amount of the fuel components in the activated carbon after purging to a greater degree than the conventional canister, and thereby reduces blow-by of the evaporation fuel components from the atmospheric air port to the outside. 
     In order to achieve the above object, the present invention provides an evaporation fuel processing device including: a passage formed inside so as to allow a fluid to flow through the passage; a tank port and a purge port formed on one end side of the passage; an atmospheric air port formed on the other end side of the passage; and adsorbent layers filled with adsorbent which can adsorb evaporation fuel components, the adsorbent layers being provided in the passage, wherein a region is provided on an atmospheric air port side of the passage, the region being constituted of three or more adsorbent layers and separating parts for separating the adjacent adsorbent layers, in which region a volume of the adsorbent layer is set smaller in the adsorbent layer closer to the atmospheric air port, a volume of the separating part is set larger in the separating part closer to the atmospheric air port, and the volume of the separating part located nearest to a tank port is set larger than the volume of the adsorbent layer located nearest to the atmospheric air port. 
     The present invention is directed to the evaporation fuel processing device described above, further wherein, in the region, the separation distance between the adjacent adsorbent layers is set longer in the separating part closer to the atmospheric air port. 
     The present invention is directed to the evaporation fuel processing device described above, further wherein, in the region, the distance between the both end surfaces of the adsorbent layer is set shorter in the adsorbent layer closer to the atmospheric air port. 
     The present invention is directed to the evaporation fuel processing device described above, further wherein, in the region, the adsorbent layer located nearest to the atmospheric air port is constituted of activated carbon having a butane working capacity of 14.5 g/dL or higher in accordance with ASTM D5228. 
     The present invention is directed to the evaporation fuel processing device described above, further wherein, the adsorbent layer disposed nearest to the tank port is constituted of pulverized coal. 
     The present invention is directed to the evaporation fuel processing device described above, further wherein, the volume of the adsorbent layers in the region is 12% or less of a total volume of the adsorbent layers in the evaporation fuel processing device. 
     The present invention is directed to the evaporation fuel processing device described above, further wherein, a ratio of a cross-sectional area, perpendicular to a flow direction in the passage, of the adsorbent layers in the region to a cross-sectional area, perpendicular to the flow direction in the passage, of the adsorbent layer outside the region in the evaporation fuel processing device falls within a range of 1:2.5 to 1:4.5. 
     During purging, a temperature decrease is large between the gas flowing into and out of the adsorbent layer near the atmospheric air port. Therefore, in the present invention, the region including the adsorbent layers and the separating parts, in which the volume of the adsorbent layer is set smaller in the adsorbent layer closer to the atmospheric air port and the volume of the separating part is set larger in the separating part closer to the atmospheric air port, is provided on the atmospheric air port side. Thus, the volume of the adsorbent layer is made smaller in the adsorbent layer farther on the atmospheric air port side, and residence time is made longer in the separating part farther on the atmospheric air port side, so that, during purging, an amount of rise (recovery) of gas temperature which has decreased due to desorption can be increased, and the gas temperature inside the evaporation fuel processing device can be maintained higher than in the conventional canister  101 . Accordingly, it is possible to improve the desorption performance, further reduce blow-by to the atmosphere, and improve the blow-by reduction performance. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view for explaining an evaporation fuel processing device according to Embodiment 1 of the present invention; 
         FIG. 2  is a schematic view for explaining an evaporation fuel processing device according to Embodiment 2 of the present invention; 
         FIG. 3  is a schematic view for explaining an evaporation fuel processing device according to Embodiment 3 of the present invention; 
         FIG. 4  is a schematic view for explaining an evaporation fuel processing device according to Embodiment 4 of the present invention; 
         FIG. 5  is a schematic view for explaining an evaporation fuel processing device according to Embodiment 5 of the present invention; and 
         FIG. 6  is a schematic cross-sectional view showing an evaporation fuel processing device of a related art. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The embodiments of the present invention will be described with reference to the drawings. 
     [Embodiment 1] 
       FIG. 1  shows Embodiment 1 of the present invention. 
     As shown in  FIG. 1 , an evaporation fuel processing device  1  of the present invention includes: a case  2 ; and a passage  3  formed inside the case  2  so as to allow a fluid to flow therethrough; a tank port  4  and a purge port  5  formed in an end part on one end side of the passage  3  in the case  2 ; and an atmospheric air port  6  formed in the end part on the other end side. 
     Four adsorbent layers: a first adsorbent layer  11 , a second adsorbent layer  12 , a third adsorbent layer  13 , and a fourth adsorbent layer  14 , each filled with adsorbent which can adsorb evaporation fuel components are serially disposed in the passage  3 . In the present embodiment, activated carbon is used as the adsorbent. 
     As shown in  FIG. 1 , a main chamber  21  communicating with the tank port  4  and the purge port  5 , and an auxiliary chamber  22  communicating with the atmospheric air port  6  are formed in the case  2 . The main chamber  21  and the auxiliary chamber  22  communicate with each other through a space  23  formed in the case  2  on a side opposite to the side of an atmospheric air port  6 , so as to cause the gas flowing in the passage  3  to flow in a substantially U-shape by turning around in the space  23 . 
     The tank port  4  communicates with an upper air chamber of a fuel tank (not shown), and the purge port  5  is connected to an air intake passage of an engine through a purge control valve (VSV) (not shown). An opening degree of this purge control valve is controlled by an electronic control unit (ECU), and during engine operation, purge control is performed on the basis of measured values and the like of an A/F sensor, etc. The atmospheric air port  6  communicates with the outside through a passage (not shown). 
     The first adsorbent layer  11 , which is filled with the activated carbon as the adsorbent at a predetermined density, is formed in the main chamber  21 . While granulated coal or pulverized coal can be used as this activated carbon, pulverized coal is used in the present embodiment. To make it clear that the first adsorbent layer  11  is constituted of the activated carbon, granulated coal is shown in the figures. 
     A baffle plate  15  extending from an inner surface of the case  2  to a part of the first adsorbent layer  1  is disposed between the tank port  4  and the purge port  5  in the case  2 . The baffle plate  15  causes the fluid flowing between the tank port  4  and the purge port  5  to pass through the first adsorbent layer  1 . 
     A side of the tank port  4  of the first adsorbent layer  11  is covered by a filter  16  made of nonwoven fabric, etc., and a side of the purge port  5  thereof is covered by a filter  17  made of nonwoven fabric, etc. In addition, a filter  18  made of urethane, etc. is provided on a surface of the first adsorbent layer  11  on a side of a space  23  so as to cover the entire end surface, and a plate  19  having a plurality of communication holes is provided under the filter  18 . The plate  19  is biased toward the side of the tank port  4  by biasing means  20  such as a spring. 
     The second adsorbent layer  12 , which is filled with the activated carbon as the adsorbent at a predetermined density, is formed on the side of the space  23  of the auxiliary chamber  22 . While granulated coal or pulverized coal can be used as this activated carbon, granulated coal is used in the present embodiment. 
     A filter  26  made of urethane, etc. is provided on the side of the space  23  of the second adsorbent layer  12  so as to cover the entire side surface. A plate  27  in which a plurality of communication holes are provided roughly evenly over the entire surface is provided on the side of the space  23  of the filter  26 . The plate  27  is biased toward the side of the atmospheric air port  6  by a biasing member  28  such as a spring. 
     The space  23  is formed between the plates  19 ,  27  and a lid plate  30  of the case  2 , and the first adsorbent layer  11  and the second adsorbent layer  12  communicate with each other through the space  23 . 
     The third adsorbent layer  13 , which is filled with the activated carbon as the adsorbent at a predetermined density, is formed on the side of the atmospheric air port  6  of the second adsorbent layer  12  in the auxiliary chamber  22 . While granulated coal or pulverized coal can be used as this activated carbon, granulated coal is used in the present embodiment. 
     A first separating part  31  which separates the adsorbent layers  12  and  13  by a predetermined distance L 1  is provided between the end surface of the second adsorbent layer  12  on the side of the atmospheric air port  6  and the end surface of the third adsorbent layer  13  on the side of the space  23 . 
     The first separating part  31  is provided with filters  35  and  36  made of urethane, etc. at an end part on the side of the second adsorbent layer  12  and at an end part on the side of the third adsorbent layer  13 , respectively, so as to cover the entire end parts. A space forming member  37  which can separate the filters  35  and  36  by a predetermined distance is provided between the filters  35  and  36 . 
     The fourth adsorbent layer  14 , which is filled with the activated carbon as the adsorbent at a predetermined density, is formed on the side of the atmospheric air port  6  of the third adsorbent layer  13  in the auxiliary chamber  22 . While granulated coal or pulverized coal can be used as this activated carbon, in the present embodiment, high-performance activated carbon having a butane working capacity (BWC) of 14.5 g/dL or higher in accordance with ASTM D5228 is used. As the activated carbon constituting the fourth adsorbent layer  14 , activated carbon similar to the activated carbon which constitutes the second adsorbent layer  12  or the third adsorbent layer  13  may be used. A filter  34  made of nonwoven fabric, etc. is provided on the side of the atmospheric air port  6  of the fourth adsorbent layer  14  so as to cover the entire end surface. 
     A second separating part  32  which separates the adsorbent layers  13  and  14  by a predetermined distance L 2  is provided between the end surface of the third adsorbent layer  13  on the side of the atmospheric air port  6  and the end surface of the fourth adsorbent layer  14  on the side of the space  23 . 
     The second separating part  32  is provided with the filters  38  and  39  made of urethane, etc. at an end part on the side of the third adsorbent layer  13  and at an end part on the side of the fourth adsorbent layer  14 , respectively, so as to cover the entire end parts. A space forming member  40  which can separate the filters  38  and  39  by a predetermined distance is provided between the filters  38  and  39 . 
     No adsorbent is provided in the separating parts  31  and  32 . 
     It is only necessary that the separating parts  31  and  32  can separate the adjacent adsorbent layers by a predetermined distance, so that they may be formed, for example, of only filters made of urethane, etc., or may be constituted of only the space forming members  37  and  40 . 
     A volume V2 of the third adsorbent layer  13  is set smaller than a volume V1 of the second adsorbent layer  12 , and a volume V3 of the fourth adsorbent layer  14  is set smaller than a volume V2 of the third adsorbent layer  13 . That is, the volume of the adsorbent layer in the auxiliary chamber  22  is set smaller in the adsorbent layer farther on the side of the atmospheric air port  6 . 
     A volume V5 of the second separating part  32  is set larger than a volume V4 of the first separating part  31 . That is, the volume of the separating part in the auxiliary chamber  22  is set larger in the separating part farther on the side of the atmospheric air port  6 . 
     A total volume of the adsorbent layers  12 ,  13 , and  14  (V1+V2+V3) in the auxiliary chamber  22  is set smaller than a total volume of the separating parts  31  and  32  (V4+V5). 
     A distance L 4  between the both end surfaces of the third adsorbent layer  13  in a flow direction in the passage  3  is set shorter than a distance L 3  between the both end surfaces of the second adsorbent layer  12  in the flow direction in the passage  3 , and a distance L 5  between the both end surfaces of the fourth adsorbent layer  14  in the flow direction in the passage  3  is set shorter than a distance L 4  between the both end surfaces of the third adsorbent layer  13  in the flow direction in the passage  3 . That is, a distance between the both end surfaces of the adsorbent layer in the auxiliary chamber  22  is set smaller in the adsorbent layer farther on the side of the atmospheric air port  6 . 
     The separation distance L 2  between the third adsorbent layer  13  and the fourth adsorbent layer  14  is set longer than a separation distance L 1  between the second adsorbent layer  12  and the third adsorbent layer  13 . That is, the separation distance between the adjacent adsorbent layers in the auxiliary chamber  22  is set longer in the separating part farther on the side of the atmospheric air port  6 . 
     A total of the distances between the both end surfaces of the adsorbent layers in the auxiliary chamber  22  (L 3 +L 4 +L 5 ) in the flow direction in the passage  3  is set shorter than a total of the separation distances between the adjacent adsorbent layers (L 1 +L 2 ). 
     The volume V4 of the first separating part  31  which is the separating part located farthest on the side of the tank port  4  is set larger than the volume V3 of the fourth adsorbent layer  14  which is the adsorbent layer located farthest on the side of the atmospheric air port  6 . 
     The region in the embodiments of the present invention indicates a portion including the adsorbent layers  12 ,  13 , and  14 , and the separating parts  31  and  32  in the auxiliary chamber  22 . 
     A total volume of the adsorbent layers  12 ,  13 , and  14  (V1+V2+V3) in the auxiliary chamber  22  is set to be 12% or less of a total volume of all the adsorbent layers in the evaporation fuel processing device  1  (V0+V1+V2+V3, where a volume of the first adsorbent layer  11  is V0). 
     A ratio of a cross-sectional area, perpendicular to the flow direction in the passage  3 , of the adsorbent layers  12 ,  13 , and  14  in the auxiliary chamber  22  to a cross-sectional area, perpendicular to the flow direction in the passage  3 , of the first adsorbent layer  11  in the main chamber  21  of the evaporation fuel processing device except for the region is set to be within a range of 1:2.5 to 1:4.5. 
     The cross-sectional areas of the second adsorbent layer  12 , the third adsorbent layer  13 , and the fourth adsorbent layer  14  perpendicular to the flow direction in the passage  3  are arbitrarily set, such as to be equal in all the layers. However, it is preferable that the cross-sectional area perpendicular to the flow direction in the passage  3  is set smaller in the adsorbent layer farther on the side of the atmospheric air port  6 . 
     Due to the above configuration, the gas containing evaporation fuel, which has flowed into the evaporation fuel processing device  1  from the tank port  4 , has the fuel components thereof adsorbed by the adsorbent in each adsorbent layer  11  to  14 , and thereafter is discharged from the atmospheric air port  6  to the atmosphere. 
     On the other hand, at the time of purge control during engine operation, the purge control valve is opened by the electronic control unit (ECU), and air suctioned from the atmospheric air port into the evaporation fuel processing device  1  due to negative pressure in the air intake passage flows in a reverse direction from the gas, and supplied from the purge port  5  to the air intake passage of the engine. Thereby, the fuel components having been adsorbed by the adsorbent in each adsorbent layer  11  to  14  are desorbed and supplied to the engine together with the air. 
     Due to the above-described structure and configuration provided in the evaporation fuel processing device  1  of the present invention, the following operations and effects are obtained. 
     Since the total volume of the separating parts  31  and  32  (V4+V5) in the auxiliary chamber  22  is set larger than the total volume of the adsorbent layers  12 ,  13 , and  14  (V1+V2+V3), the residence time in the separating parts can be made longer than in the conventional canister  101 , so that an amount of rise (recovery) of the gas temperature which has decreased due to desorption in one of the adsorbent layer becomes larger. Accordingly, the temperature of the gas flowing into the adsorbent layer located on the side of the tank port  4  of the one adsorbent layer can be maintained higher than in the conventional canister  101 , and thereby high performance of the adsorbent for desorbing the evaporation fuel components can be maintained. Thus, by reducing the residual amount of the fuel components in the evaporation fuel processing device  1  after purging to a greater degree than the conventional canister  101 , it is possible to reduce the amount of blow-by to the atmosphere and improve the blow-by reduction performance. 
     Since the total volume of the separating parts  31  and  32  (V4+V5) in the auxiliary chamber  22  is set larger than the total volume of the adsorbent layers  12 ,  13 , and  14  (V1+V2+V3), and the total of the separation distances between the adjacent adsorbent layers (L 1 +L 2 ) is set longer than the total of the distances between the both end surfaces of the adsorbent layers (L 3 +L 4 +L 5 ), the residence time in the separating parts can be more reliably increased, and the amount of recovery of the gas temperature which has decreased due to desorption can be reliably increased to a greater degree than the conventional canister  101 . Thus, by maintaining high desorption performance of the adsorbent, it is possible to reduce the residual amount of the evaporation fuel components after purging and to improve the blow-by reduction performance. 
     Since the volume of the adsorbent layer in the auxiliary chamber  22  is set smaller in the adsorbent layer farther on the side of the atmospheric air port  6 , the residual amount of the fuel components after purging can be reduced to a greater degree in the adsorbent layer farther on the side of the atmospheric air port  6 . Thereby, it is possible to reduce the blow-by of the fuel components to the atmosphere and improve the blow-by reduction performance. 
     In addition, since the volume of the adsorbent layer in the auxiliary chamber  22  is set smaller in the adsorbent layer farther on the side of the atmospheric air port  6 , and the distance between the both end surfaces of the adsorbent layer is set shorter in the adsorbent layer farther on the side of the atmospheric air port  6 , it is possible to further reduce the blow-by of the fuel components to the atmosphere and improve the blow-by reduction performance. 
     During purging, a temperature difference between the gas flowing into and out of the adsorbent layer is larger in the adsorbent layer closer to the atmospheric air port  6 . For this reason, if the residence time can be made longer in the separating part located farther on the atmospheric air port side, where a temperature decrease is large, and the reduced gas temperature can be increased, then high desorption performance of the adsorbent can be maintained, so that the desorption efficiency of the evaporation fuel components from the adsorbent in the adsorbent layer on the tank port  4  side of the separating part can be improved. Therefore, in the present invention, the volume of the separating parts  31  and  32  are set larger in the separating part closer to the atmospheric air port  6 , where the temperature decrease is large, so as to make the residence time in the separating part longer in the separating part farther on the side of the atmospheric air port  6 . Thereby, it has become possible to maintain the gas temperature higher than in the conventional canister  101  and to improve the desorption performance of the evaporation fuel processing device  1 . Accordingly, the blow-by of the fuel components to the atmosphere can be reduced to a greater degree than in the conventional canister  101 , and the blow-by reduction performance can be increased. 
     The volumes of the separating parts  31  and  32  are set larger in the separating part farther on the side of the atmospheric air port  6  and the separation distance between the adjacent adsorbent layers is set longer in the separating part farther on the side of the atmospheric air port  6 . Thereby, the residence time in the separating parts can be made longer and the amount of rise of the reduced gas temperature can be made larger than in the conventional canister  101 , so that the desorption performance of the evaporation fuel processing device  1  can be improved. Thus, it is possible to reduce the blow-by to the atmosphere to a greater degree than the conventional canister  101  and to improve the blow-by reduction performance. 
     Since the cross-sectional area perpendicular to the flow direction in the passage  3  is made smaller in the adsorbent layer farther on the side of the atmospheric air port  6 , a flow rate of the gas per unit area during purging can be made higher in the adsorbent layer farther on the side of the atmospheric air port  6 , and the residual amount of the evaporation fuel components in the fourth adsorbent layer  14  can be reduced. Thereby, it is possible to reduce the blow-by to the atmosphere and improve the blow-by reduction performance. 
     [Embodiment 2] 
     While in Embodiment 1, the U-shaped passage  3  which is folded back once in the space  23  is formed in the case  2 , for example, a passage  41  formed in an N-shape which is folded back twice may be provided in the case  2  as shown in  FIG. 2 . 
     The structure of the main chamber  21  in Embodiment 2 is the same as that of the main chamber  21  in Embodiment 1. In Embodiment 2, an auxiliary chamber  42  corresponding to the region in Claim  1  is formed in a U-shape which is folded back in a space  43 . One end of the auxiliary chamber  42  communicates with the space  23 , and the other end is provided with the atmospheric air port  6 . 
     The second adsorbent layer  12  and the third adsorbent layer  13  similar to those in Embodiment 1 are provided between the spaces  23  and  43  in the auxiliary chamber  42 , and the first separating part  31  is formed between the second adsorbent layer  12  and the third adsorbent layer  13 . In addition, the fourth adsorbent layer  14  similar to the fourth adsorbent layer  14  of Embodiment 1 is provided on the side of the atmospheric air port  6  of the space  43 . The second separating part  32  is provided between the fourth adsorbent layer  14  and the third adsorbent layer  13 . 
     Mutual relationships among the adsorbent layers  11 ,  12 ,  13 , and  14 , and the separating parts  31  and  32  are set in a similar manner to Embodiment 1. That is, as in Embodiment 1, the volume of the adsorbent layer in the auxiliary chamber  42  is set smaller in the adsorbent layer farther on the side of the atmospheric air port  6 ; the volume of the separating part in the auxiliary chamber  42  is set larger in the separating part farther on the side of the atmospheric air port  6 ; and the total volume of the adsorbent layers  12 ,  13 , and  14  (V1+V2+V3) in the auxiliary chamber  42  is set smaller than the total volume of the separating parts  31  and  32  (V4+V5). 
     In addition, as in Embodiment 1, the distance between the both end surfaces of the adsorbent layer in the auxiliary chamber  42  is set shorter in the adsorbent layer farther on the side of the atmospheric air port  6 ; the separation distance between the adjacent adsorbent layers in the auxiliary chamber  42  is set longer in the separating part farther on the side of the atmospheric air port  6 ; and the total of the distances between the both end surfaces of the adsorbent layers (L 3 +L 4 +L 5 ) in the auxiliary chamber  42  is set shorter than the total of the separation distances between the adjacent adsorbent layers (L 1 +L 2 ). The separation distance L 2  between the third adsorbent layer  13  and the fourth adsorbent layer  14  means the separation distance in an axial direction between the end surface of the third adsorbent layer  13  on the side of the atmospheric air port  6  and the end surface of the fourth adsorbent layer  14  on the side of the tank port  4 . As shown in  FIG. 2 , the separation distance L 2  corresponds to a total distance L 2 ′+L 2 ″, where L 2 ′ is a distance between the end surface of the third adsorbent layer  13  on the side of the atmospheric air port  6  and an inlet end on the end surface of the space  43  on the side of the tank port  4 , and L 2 ″ is a distance between the end surface of the space  43  on the side of the atmospheric air port  6  and the end surface of the fourth adsorbent layer  14  on the side of the tank port  4 . 
     The volume V4 of the first separating part  31  which is the separating part located farthest on the side of the tank port  4  is set larger than the volume V3 of the fourth adsorbent layer  14  which is the adsorbent layer located farthest on the side of the atmospheric air port  6 . 
     The total volume of the adsorbent layers  12 ,  13 , and  14  in the auxiliary chamber  22  (V1+V2+V3) is set to be 12% or less of the total volume of all the adsorbent layers in the evaporation fuel processing device  1  (V0+V1+V2+V3). 
     A ratio of the cross-sectional area, perpendicular to the flow direction in the passage  3 , of the adsorbent layers  12 ,  13 , and  14  in the auxiliary chamber  42  to the cross-sectional area, perpendicular to the flow direction in the passage  3 , of the first adsorbent layer  11  in the main chamber  21  of the evaporation fuel processing device except for the region is set to be within a range of 1:2.5 to 1:4.5. 
     Other members, which are the same as those in Embodiment 1, are denoted by the same reference numerals and a description thereof is omitted here. 
     In addition, the same operations and effects as in Embodiment 1 are obtained also in Embodiment 2. 
     [Embodiment 3] 
     A shape of a passage in Embodiment 3 is different from that of the passages  3  and  41  of Embodiments 1 and 2, and for example, a passage  51  formed in a W-shape which is folded back three times may be provided in the case  2  as shown in  FIG. 3 . 
     The structure of the main chamber  21  in Embodiment 3 is the same as that of the main chamber  21  in Embodiment 1. An auxiliary chamber  52  in Embodiment 3 corresponding to the region in Claim  1  is formed in an N-shape which is folded back twice in spaces  53  and  54 . One end of the auxiliary chamber  52  communicates with the space  23 , and the other end is provided with the atmospheric air port  6 . 
     The second adsorbent layer  12  and the third adsorbent layer  13  similar to those in Embodiment 1 are provided between the spaces  23  and  35  in the auxiliary chamber  52 , and the first separating part  31  is provided between the second adsorbent layer  12  and the third adsorbent layer  13 . In addition, the fourth adsorbent layer  14  similar to the fourth adsorbent layer  14  of Embodiment 1 is provided between the spaces  53  and  54 . The second separating part  32  is provided between the fourth adsorbent layer  14  and the third adsorbent layer  13 . 
     Mutual relationships among the adsorbent layers  11 ,  12 ,  13 , and  14 , and the separating parts  31  and  32  are set in a similar manner to Embodiment 1. 
     Other members, which are the same as those in Embodiments 1 and 2, are denoted by the same reference numerals and a description thereof is omitted here. 
     In addition, the same operations and effects as in Embodiments 1 and 2 are obtained also in Embodiment 3. 
     [Embodiment 4] 
     While in Embodiment 1, the passage  3  in the case  2  is formed in a U-shape which is folded back once in the space  23 , for example, as shown in  FIG. 4 , the passage in the case may be formed in an I-shape without folding back. 
     For example, as shown in  FIG. 4 , Embodiment 4 is an evaporation fuel processing device in which the main chamber  21  and the auxiliary chamber  22  are linearly arranged without folding back in the space. 
     Also in Embodiment 4, an auxiliary chamber, which is the region which includes the three adsorbent layers and the separating parts for separating the adjacent adsorbent layers, and in which the volume of the adsorbent layer is set smaller in the adsorbent layer closer to the atmospheric air port  6 ; the volume of the separating part is set larger in the separating part closer to the atmospheric air port; and the volume of the separating part located farthest on the tank port side is set larger than the volume of the adsorbent layer located farthest on the atmospheric air port side, is provided on the side of the atmospheric air port  6 . 
     Mutual relationships between the adsorbent layers  11 ,  12 ,  13  and  14 , and the separating parts  31  and  32  are set in a similar manner to Embodiment 1. 
     Other members, which are the same as those in Embodiment 1, are denoted by the same reference numerals and a description thereof is omitted here. 
     In addition, the same operations and effects as in Embodiment 1 are obtained also in Embodiment 4. 
     [Embodiment 5] 
       FIG. 5  shows one example of Embodiment 5 of the present invention. 
     An evaporation fuel processing device  61  of Embodiment 5 includes a main body canister  62  and a sub-canister  63 , and the main body canister  62  and the sub-canister  63  communicate with each other through a communication pipe  64 . 
     As in Embodiment 1, the main chamber  21  and the auxiliary chamber  22  are formed in the main body canister  62 ; the first adsorbent layer  11  is provided in the main chamber  21 ; the second adsorbent layer  12  and the third adsorbent layer  13  similar to those in Embodiment 1 are provided in the auxiliary chamber  22 ; and the first separating part  31  is provided between the second adsorbent layer  12  and the third adsorbent layer  13 . In addition, the fourth adsorbent layer  14  similar to that of Embodiment 1 is provided in the sub-canister  63 . A second separating part  66  is provided between the third adsorbent layer  13  and the fourth adsorbent layer  14  across the auxiliary chamber  22  and the sub-canister  63 . 
     The auxiliary chamber  22  in the main body canister  62  and the sub-canister  63  correspond to the region in Claim  1 . 
     Mutual relationships among the adsorbent layers  11 ,  12 ,  13 , and  14 , and the separating parts  31  and  66  are set in a similar manner to Embodiment 1. In these mutual relationships, a distance between the spaces except for the communication pipe  64 , namely, L 6 +L 7  in  FIG. 5 , is preferably used as the separation distance L 2  between the third adsorbent layer  13  and the fourth adsorbent layer  14  in forming the adsorbent layers  11 ,  12 ,  13 , and  14  and the separating parts  31  and  66  so that the mutual relationships in Embodiment 1 are established. This is because in the communication pipe  64 , which has a small cross-sectional area of a flow path, a flow velocity increases and the residence time in that part becomes short. 
     Other members, which are the same as those in Embodiments 1, are denoted by the same reference numerals and a description thereof is omitted here. 
     In addition, the same operations and effects as in Embodiment 1 are obtained also in Embodiment 5. 
     [Other Embodiments] 
     While in Embodiments 1 to 5, only the first adsorbent layer  11  is provided in the main chamber  21 , a plurality of adsorbent layers may be provided in the main chamber  21 , and between the adjacent adsorbent layers, the separating part for separating them may be provided. 
     Further, four or more adsorbent layers may be serially disposed in the auxiliary chamber  22 , and between the adjacent adsorbent layers, the separating part for separating them may be provided. In this case, the volume of the adsorbent layer in the auxiliary chamber  22  is set smaller in the adsorbent layer farther on the side of the atmospheric air port  6 ; the volume of the separating part in the auxiliary chamber  22  is set larger in the separating part farther on the side of the atmospheric air port  6 ; the total volume of the adsorbent layers in the auxiliary chamber  22  is set smaller than the total volume of the separating parts; the distance between the both end surfaces of the adsorbent layer in the auxiliary chamber  22  is set shorter in the adsorbent layer farther on the side of the atmospheric air port  6 ; the separation distance between the adjacent adsorbent layers in the auxiliary chamber  22  is set longer in the separating part farther on the side of the atmospheric air port  6 ; and the total of the distances between the both end surfaces of the adsorbent layers in the auxiliary chamber  22  is set shorter than the total of the separation distances between the adjacent adsorbent layers. 
     The shape of the entire evaporation fuel processing device, and the number, the shape, the arrangement, etc. of the adsorbent layer, the separating part, the space, and the like can be arbitrarily set, as long as the auxiliary chamber is provided on the side of the atmospheric air port  6 , the auxiliary chamber being the region which includes three or more adsorbent layers and the separating parts for separating the adjacent adsorbent layers, and in which the volume of the adsorbent layer is set smaller in the adsorbent layer closer to the atmospheric air port, the volume of the separating part is set larger in the separating part closer to the atmospheric air port, and the volume of the separating part located nearest to the tank port is set larger than the volume of the adsorbent layer located nearest to the atmospheric air port.