Evaporative fuel treatment device

Abstract

A vaporized fuel processing device is provided, which comprises a main adsorption chamber and a sub-adsorption chamber. The sub-adsorption chamber comprises a first adsorption layer, a second adsorption layer, and a high desorption layer. The second adsorption layer is located closer to the atmosphere port than the first adsorption layer, and the fuel vapor adsorption performance of the second adsorption layer is lower than that of the first adsorption layer. The high desorption layer is located closer to the main adsorption chamber than the first adsorption layer, and the fuel vapor desorption performance of the high desorption layer is better than that of the first adsorption layer and the second adsorption layer.

Description

Technical Field

[0001] The present disclosure relates to an evaporative fuel treatment device for adsorbing fuel vapor generated from a fuel tank. Background Art

[0002] There is known an evaporative fuel processing device equipped with an adsorbent material such as activated carbon. The evaporative fuel processing device is provided with an inlet connected to a fuel tank and an outlet connected to an internal combustion engine. The fuel vapor flowing in from the inlet is adsorbed by the adsorbent material provided in each chamber of the evaporative fuel processing device. In addition, an atmospheric port is provided in the evaporative fuel processing device. When the adsorbed fuel vapor is desorbed and sent to the internal combustion engine, that is, when purging is performed, purging air is flowed in from outside the vehicle through the atmospheric port. The fuel adsorbed to the adsorbent material is removed by the purging air, and the removed fuel flows out from the outlet to the internal combustion engine.

[0003] Japanese Patent Gazette No. 6507092 discloses an evaporative fuel treatment device having a third chamber near an atmospheric port, the third chamber having a low adsorption layer and a high adsorption layer in order from the atmospheric port side. The third chamber functions as a trapping device for suppressing the emission of fuel vapor from the atmospheric port. In addition, Patent Document 1 discloses a configuration in which honeycomb activated carbon is arranged between the low adsorption layer and the atmospheric port. Summary of the invention

[0004] In recent years, there is a tendency to reduce the amount of purge air in order to meet fuel efficiency restrictions, etc. If the amount of purge air is reduced, fuel vapor is likely to remain inside the evaporated fuel processing device, and fuel vapor is likely to flow out from the atmosphere port.

[0005] One aspect of the present disclosure preferably provides an evaporated fuel processing device having improved performance.

[0006] One aspect of the present disclosure relates to an evaporative fuel processing device, which includes an inlet, an outlet, and an atmospheric port. The evaporative fuel processing device accumulates fuel vapor flowing in from a fuel tank through the inlet. The evaporative fuel processing device causes the accumulated fuel vapor to flow out to an internal combustion engine through the outlet by air flowing in from the atmospheric port.

[0007] The evaporative fuel treatment device includes a main adsorption chamber and a sub-adsorption chamber. The main adsorption chamber is connected to an inlet and an outlet, and is provided with an adsorption material for adsorbing fuel vapor. The sub-adsorption chamber is connected to an atmospheric port, and is provided with an adsorption material for adsorbing fuel vapor. Furthermore, the sub-adsorption chamber has a first adsorption layer, a second adsorption layer, and a high desorption layer. The second adsorption layer is located closer to the atmospheric port than the first adsorption layer, and the adsorption performance of the fuel vapor of the second adsorption layer is lower than that of the first adsorption layer. The high desorption layer is located closer to the main adsorption chamber than the first adsorption layer, and the desorption performance of the fuel vapor of the high desorption layer is better than that of the first adsorption layer and the second adsorption layer.

[0008] According to the above structure, a large amount of fuel vapor can be adsorbed by the first adsorption layer which is farther from the atmosphere port than the second adsorption layer. Therefore, the amount of fuel vapor remaining at a position close to the atmosphere port can be reduced, thereby suppressing the fuel vapor from flowing out of the atmosphere port. Moreover, the auxiliary adsorption chamber can desorb the fuel vapor from the adsorption material well even with a small amount of purge air. The reasons include the following two points. (i) During purge, the fuel vapor is effectively desorbed in the first adsorption layer and the second adsorption layer by the clean air flowing in from the atmosphere port. (ii) The high desorption layer has excellent desorption performance, so the fuel vapor can also be desorbed well by the purge air that has passed through the first adsorption layer and the second adsorption layer. As described above, the evaporative fuel processing device of the above structure can both suppress the fuel vapor from flowing out of the atmosphere port and desorb the fuel vapor well during purge.

[0009] The high desorption layer may include activated carbon formed into a honeycomb shape. According to the above structure, the desorption property of the high desorption layer can be improved. This is because the thickness of the activated carbon is reduced by forming the activated carbon into a honeycomb shape, thereby making it easy to desorb the fuel vapor adsorbed deep in the pores of the activated carbon.

[0010] The main adsorption chamber may include a first main adsorption chamber and a second main adsorption chamber that are connected to each other via a connecting passage. The first main adsorption chamber and the second main adsorption chamber may be arranged such that when fuel vapor from a fuel tank flows in, a flow direction of the fuel vapor in the first main adsorption chamber is opposite to a flow direction of the fuel vapor in the second main adsorption chamber, and the first main adsorption chamber and the second main adsorption chamber are arranged side by side in a direction intersecting with the flow direction of the fuel vapor in the first main adsorption chamber.

[0011] According to the above configuration, the main adsorption chamber can be prevented from being restricted in shape, and as a result, the evaporative fuel processing device can have more options for adopting shapes. This makes it easier to mount the evaporative fuel processing device in, for example, an engine room where the installation space is limited.

[0012] In the evaporated fuel processing device of one aspect of the present disclosure, the first adsorption layer and the second adsorption layer may include activated carbon as an adsorption material. According to the above configuration, the double-layer structure composed of the first adsorption layer and the second adsorption layer can have a very high adsorption performance. Therefore, the adsorption capacity of the evaporated fuel processing device as a whole can be increased.

[0013] The adsorbent provided in the high desorption layer may include a portion in the form of a thin plate. According to the above configuration, the specific surface area of ​​the adsorbent is increased, so the desorption property of the high desorption layer can be improved.

[0014] In addition, the first adsorption layer and the second adsorption layer may have a granular or pellet-shaped component as an adsorption material. In addition, the thin plate-shaped portion may be thinner than the granular or pellet-shaped component. According to the above structure, it is easy to achieve that the desorption performance of the high desorption layer is higher than the desorption performance of the first adsorption layer and the second adsorption layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is an explanatory diagram schematically showing the internal structure of the evaporated fuel processing device according to the embodiment.

[0016] Figure 2 It is an explanatory diagram schematically showing the internal structure of an evaporated fuel processing device according to a modified example. DETAILED DESCRIPTION

[0017] Exemplary embodiments of the present disclosure are described below with reference to the accompanying drawings.

[0018] [1. Implementation Method]

[0019] [1-1. Overall structure]

[0020] Figure 1 The evaporated fuel processing device 1 shown has a housing 10 made of synthetic resin. The housing 10 includes a first main adsorption chamber 20, a second main adsorption chamber 30, and a sub-adsorption chamber 40. The evaporated fuel processing device 1 also includes an inlet 11, an outlet 12, an air port 13, and a cover member 14 provided in the housing 10.

[0021] The first main adsorption chamber 20 is provided with an inlet 11 and an outlet 12 at the front end in the first direction. In addition, the first main adsorption chamber 20 is provided with a cover member 14 at the front end in the second direction opposite to the first direction. The cover member 14 extends in a direction intersecting the second direction. The first main adsorption chamber 20 and the second main adsorption chamber 30 are arranged on the side of the cover member 14 close to the first direction. The first main adsorption chamber 20 and the second main adsorption chamber 30 are connected via a connecting passage 15 formed inside the cover member 14. The second main adsorption chamber 30 is provided with an auxiliary adsorption chamber 40 at the end in the first direction. The auxiliary adsorption chamber 40 is provided with an air port 13 at the end in the first direction.

[0022] An adsorbent is disposed inside the housing 10. The evaporative fuel processing device 1 accumulates fuel vapor flowing in from a fuel tank (not shown) through an inlet 11 in the adsorbent. The evaporative fuel processing device 1 also causes the accumulated fuel vapor to flow out to the internal combustion engine through an outlet 12 by air flowing in from the outside through an air port 13.

[0023] In order to facilitate understanding of the description, the fuel vapor flowing in from the fuel tank in an adsorbed state is also referred to as fuel vapor. The fuel vapor contains hydrocarbons as a main constituent element.

[0024] The first main adsorption chamber 20 and the second main adsorption chamber 30 are mainly configured to adsorb and store a large amount of fuel vapor. Hereinafter, the first main adsorption chamber 20 and the second main adsorption chamber 30 are sometimes referred to as main adsorption chambers. On the other hand, the auxiliary adsorption chamber 40 not only has the function of adsorbing fuel vapor, but also has the function of serving as a trapping device that suppresses the outflow of fuel vapor from the atmosphere port 13.

[0025] The inlet 11 is connected to the fuel tank of the vehicle equipped with the evaporated fuel processing device 1 via a valve. When the fuel vapor generated by the fuel stored in the fuel tank flows into the evaporated fuel processing device 1 via the inlet 11, the fuel vapor is adsorbed by the adsorbent disposed in each chamber. As a result, the fuel is stored in the evaporated fuel processing device 1.

[0026] The outflow port 12 is connected to the intake pipe of the internal combustion engine of the vehicle via a valve. In addition, the atmospheric port 13 is connected to the outside of the internal combustion engine and the evaporated fuel processing device 1. In the present embodiment, the atmospheric port 13 is connected to the outside of the vehicle. Moreover, the air in the atmosphere (hereinafter referred to as the sweeping air) is caused to flow into the inside of the evaporated fuel processing device 1 via the atmospheric port 13 by utilizing the negative pressure of the intake of the internal combustion engine. At this time, the fuel adsorbed on the adsorbent material is desorbed by the sweeping air, and the desorbed fuel flows out to the intake pipe via the outflow port 12. In this way, the fuel adsorbed on the adsorbent material is removed, thereby regenerating the adsorbent material. The situation of discharging the adsorbed fuel and regenerating the adsorbent material as described above is hereinafter referred to as sweeping.

[0027] [1-2. Main adsorption chamber]

[0028] The first main adsorption chamber 20 is connected to the inlet 11 and the outlet 12. In the first main adsorption chamber 20, an adsorbent 23 for adsorbing fuel vapor is arranged.

[0029] The first main adsorption chamber 20 has a generally rectangular parallelepiped shape that is a hollow cylinder. A filter 21 is disposed at the end of the first direction side of the first main adsorption chamber 20, and a filter 22 and a porous plate 17 are disposed at the end of the second direction side of the first main adsorption chamber 20. The adsorption material 23 is filled between the filter 21 and the filter 22. The filter 21 and the filter 22 are constructed so as to allow the passage of gases such as fuel vapor while not allowing the passage of the filling material. Like the filter 22, the porous plate 17 allows the passage of gas. The porous plate 17 can support the filter 22. The porous plate 17 is forced in the first direction by a force-applying member such as a coil spring not shown.

[0030] The second main adsorption chamber 30 is located between the first main adsorption chamber 20 and the auxiliary adsorption chamber 40 on the flow path of the gas. An adsorption material 33 for adsorbing fuel vapor is arranged in the second main adsorption chamber 30. A filter 31 and a porous plate 18 are arranged at the end of the second main adsorption chamber 30 on the first direction side, and a filter 32 and a porous plate 19 are arranged at the end of the second main adsorption chamber 30 on the second direction side. The adsorption material 33 is filled between the filter 31 and the filter 32. Like the filter 21 and the filter 22, the filter 31 and the filter 32 are also constructed to allow the gas such as fuel vapor to pass through while not allowing the filling material to pass through. In addition, the structure of the porous plate 18 and the porous plate 19 is the same as that of the porous plate 17. The porous plate 19 is forced in the first direction by a force member such as a coil spring not shown.

[0031] When the fuel vapor flows from the fuel tank into the first main adsorption chamber 20, the fuel vapor flows in the second direction. When the fuel vapor flows into the second main adsorption chamber 30, the fuel vapor flows in the first direction. That is, the first main adsorption chamber 20 and the second main adsorption chamber 30 are arranged so that when the fuel vapor from the fuel tank flows in, the flow direction of the fuel vapor in the first main adsorption chamber 20 and the flow direction of the fuel vapor in the second main adsorption chamber 30 are opposite directions. In addition, the first main adsorption chamber 20 and the second main adsorption chamber 30 are arranged side by side in a direction intersecting with the flow direction of the fuel vapor in the first main adsorption chamber 20.

[0032] [1-3. Sub-adsorption chamber]

[0033] The sub-adsorption chamber 40 is located between the second main adsorption chamber 30 and the atmospheric port 13 on the gas flow path. An adsorbent for adsorbing fuel vapor is disposed in the sub-adsorption chamber 40. The sub-adsorption chamber 40 includes a stacked portion 50 and a high desorption layer 60.

[0034] The stacking part 50 is formed as an elongated space with a constant width. The stacking part 50 in the present embodiment is in a hollow cylindrical shape, and a cross section of the stacking part 50 cut by a plane orthogonal to the air flow direction (i.e., the first direction or the second direction) is circular. However, the shape of the stacking part 50 is not limited thereto, and for example, the stacking part 50 may also be formed in a polygonal column shape.

[0035] The stacked portion 50 includes a first adsorption layer 51 and a second adsorption layer 52. The first adsorption layer 51 is located closer to the main adsorption chamber than the second adsorption layer 52, and is provided with a first adsorption material 53. The second adsorption layer 52 is located closer to the atmospheric port 13 than the first adsorption layer 51, and is provided with a second adsorption material 54. Each adsorption layer will be described in detail later. In addition, the distance is determined based on the flow path of the fuel vapor. That is, the fuel vapor moving from the main adsorption chamber (specifically, the second main adsorption chamber 30) toward the atmospheric port 13 enters the first adsorption layer 51 before the second adsorption layer 52. In addition, when purging is performed, the purge air flowing in through the atmospheric port 13 enters the second adsorption layer 52 before the first adsorption layer 51.

[0036] A filter 71 is disposed at the end portion on the second direction side of the first adsorption layer 51. A filter 72 is disposed at the end portion on the first direction side of the first adsorption layer 51, that is, between the first adsorption layer 51 and the second adsorption layer 52. A filter 73 is disposed at the end portion on the first direction side of the second adsorption layer 52. The first adsorption material 53 constituting the first adsorption layer 51 is disposed between the filter 71 and the filter 72. In addition, the second adsorption material 54 constituting the second adsorption layer 52 is disposed between the filter 72 and the filter 73.

[0037] The high desorption layer 60 is arranged at a position closer to the second main adsorption chamber 30 than the first adsorption layer 51 of the stacked portion 50. The high desorption layer 60 includes a third adsorption material 61, and the desorption performance of the fuel vapor of the third adsorption material 61 is better than that of the first adsorption layer 51 and the second adsorption layer 52. The "close to ... side" mentioned here means the close to ... side when arranged in sequence on the flow path of the fuel vapor as described above. The third adsorption material 61 is activated carbon formed into a honeycomb shape. The adsorption material will be described in detail later.

[0038] As described above, the sub-adsorption chamber 40 has the second adsorption layer 52, the first adsorption layer 51, and the third adsorption material 61 arranged in order from the end side in the first direction toward the second direction. When the fuel vapor is stored, the fuel vapor flows from the second main adsorption chamber 30 to the third adsorption material 61, the first adsorption layer 51, and the second adsorption layer 52 in order. In addition, the air existing in the evaporated fuel processing device 1 is discharged from the atmospheric port 13. When purging is performed, the purge air entering from the atmospheric port 13 enters the second adsorption layer 52, the first adsorption layer 51, and the high desorption layer 60 in order, and flows into the second main adsorption chamber 30.

[0039] The structure and arrangement of the filters and the porous plates are not particularly limited, and various structures may be used as long as the movement of the adsorbent can be suppressed and the air can be moved.

[0040] [1-4. Adsorbent material arranged in the auxiliary adsorption chamber]

[0041] The first adsorbent 53 constituting the first adsorbent layer 51 and the second adsorbent 54 constituting the second adsorbent layer 52 are both activated carbon. The first adsorbent 53 and the second adsorbent 54 are formed into granular or cylindrical pellets and filled in a predetermined space of the auxiliary adsorbent chamber 40. That is, the first adsorbent layer 51 is composed of a large amount of the first adsorbent 53, and the second adsorbent layer 52 is composed of a large amount of the second adsorbent 54.

[0042] The fuel vapor adsorption performance of the second adsorption layer 52 is lower than that of the first adsorption layer 51. The adsorption performance mentioned here refers to the adsorption capacity of the activated carbon constituting each layer as a whole. In addition, the adsorption capacity refers to the butane working capacity (i.e., BWC) specified by ASTM5228. The specific structure for making the adsorption performance of the first adsorption layer 51 and the adsorption performance of the second adsorption layer 52 different is not particularly limited. For example, the adsorption performance can be set to be different by adjusting the thickness of each layer, the physical properties of the adsorption material, the filling amount of the adsorption material, the shape of the adsorption material, the structure of the adsorption material, etc.

[0043] Each layer may be provided with activated carbon selected from activated carbons having an adsorption capacity of, for example, 17 g / dL, 15 g / dL, 11 g / dL, 9 g / dL, and 7 g / dL. Specific examples of the activated carbon include activated carbons BAX1700, BAX1500, BAX1100, and BAX LBE manufactured by Ingevity.

[0044] In addition, the length of the first adsorption layer 51 and the second adsorption layer 52 of the auxiliary adsorption chamber 40 in the flow direction of the fuel vapor is set to L. The above-mentioned flow direction is a direction along the first direction or the second direction. In addition, the length of the first adsorption layer 51 and the second adsorption layer 52 in a direction orthogonal to the first direction is set to D. This direction is the width direction of the first adsorption layer 51 and the second adsorption layer 52. D is equivalent to the diameter of the cylindrical hollow portion of the stacked portion 50. D may be smaller than the width of the internal space of the second main adsorption chamber 30.

[0045] The L of the first adsorption layer 51 may be smaller than the L of the second adsorption layer 52. In addition, the L / D of the first adsorption layer 51 and the L / D of the second adsorption layer 52 may both be smaller than 1. Of course, the present invention is not limited thereto, and the L of the first adsorption layer 51 may also be larger than the L of the second adsorption layer 52. Furthermore, one or both of the L / D of the first adsorption layer 51 and the L / D of the second adsorption layer 52 may be greater than or equal to 1.

[0046] The amount of purge air flowing in from the atmospheric port 13 due to purge is referred to as a purge amount. The values ​​of L and D or L / D of each layer, the ratio of L of each layer, the type of activated carbon of each layer, etc. may be selected so that the fuel adsorbed in the activated carbon arranged in the auxiliary adsorption chamber 40 can be sufficiently removed by flowing in the purge air having a purge amount specified according to the vehicle type from the atmospheric port 13.

[0047] The third adsorbent 61 disposed in the high desorption layer 60 is a cylindrical member in a honeycomb shape capable of adsorbing and desorbing fuel vapor. The third adsorbent 61 may be formed as a mass. The honeycomb shape mentioned here broadly includes a honeycomb shape extending in a single direction and forming a plurality of cells as fluid flow paths. For example, in addition to a honeycomb shape in the strict sense in which the cross section of the cells is approximately hexagonal, the cross section of the cells may also be circular, rectangular, triangular, rhombus, etc.

[0048] The wall forming the pores in the third adsorbent 61 may be made of activated carbon. For example, the third adsorbent 61 may be formed by solidifying activated carbon with a binder. Since the third adsorbent 61 having a honeycomb structure is hollow, the thickness of the wall is reduced compared to, for example, the case where activated carbon having the same adsorption capacity is formed into a granular or pellet shape. If the thickness of the activated carbon is small, the fuel vapor adsorbed deep in the pores is easily desorbed. Therefore, the high desorption layer 60 having the third adsorbent 61 has a better desorption performance of fuel vapor than the first adsorption layer 51 and the second adsorption layer 52 having the first adsorbent 53 and the second adsorbent 54, respectively.

[0049] Next, the method for comparing desorption performance is described. The activated carbon is allowed to adsorb hydrocarbon components until breakthrough is achieved, and clean air having an amount that does not completely desorb the adsorbed hydrocarbon components is flowed into the activated carbon at a flow rate equivalent to that of a vehicle flushing. Then, the ratio of the desorbed hydrocarbon components to the adsorbed hydrocarbon components is calculated. The larger the value, the better the desorption performance.

[0050] [1-5. Effect]

[0051] (1a) In the evaporated fuel processing device 1, a large amount of fuel vapor can be adsorbed by the first adsorption layer 51 in the stacked portion 50, which is farther from the atmospheric port 13 than the second adsorption layer 52. Therefore, a large amount of fuel can be retained at a position far from the atmospheric port 13, and the amount of fuel retained at a position close to the atmospheric port 13 can be reduced, so that the outflow of fuel vapor from the atmospheric port 13 can be suppressed.

[0052] Furthermore, the auxiliary adsorption chamber 40 can desorb the fuel vapor from the adsorbent material well even when a small amount of purge air is used. This is because the stacked portion 50 is arranged closer to the atmospheric port 13 than the high desorption layer 60, so that the fuel vapor is effectively desorbed by the clean air flowing in from the atmospheric port 13 during the purge. In addition, the high desorption layer 60 has excellent desorption performance, so even if the fuel vapor desorbed in the stacked portion 50 is adsorbed again in the high desorption layer 60, the adsorbed fuel vapor will not be retained and is easily desorbed. As a result, the auxiliary adsorption chamber 40 has a high desorption property for the fuel vapor.

[0053] As described above, the evaporated fuel processing device 1 having the above-described structure can suppress the outflow of the fuel vapor from the atmosphere port 13 and can also effectively desorb the fuel vapor during the purge.

[0054] (1b) The third adsorbent 61 has a honeycomb shape and thus has a high desorption property for fuel vapor. Therefore, the desorption property for fuel vapor in the auxiliary adsorption chamber 40 can be made very high, and the outflow of fuel vapor from the atmosphere port 13 can be highly suppressed. In addition, the adsorbed fuel vapor can be sufficiently removed by purging with a small amount of purge air, and the amount of fuel vapor accumulated in the auxiliary adsorption chamber 40 can be increased.

[0055] (1c) The first main adsorption chamber 20 and the second main adsorption chamber 30 are arranged in the same direction with respect to the cover member 14. Therefore, the increase in the overall length of the evaporated fuel processing device 1 can be suppressed, and the overall shape freedom of the main adsorption chamber can be improved, resulting in an increase in the shape freedom of the evaporated fuel processing device 1. As a result, the evaporated fuel processing device 1 can be used even in an engine room where the installation space is limited, for example.

[0056] (1d) Since the stacked portion 50 uses activated carbon as the adsorbent, the adsorption performance of the stacked portion 50 can be made very high. Therefore, the adsorption capacity of the entire evaporated fuel processing device 1 can be increased.

[0057] (le) L / D of the first adsorption layer 51 and the second adsorption layer 52 are both less than 1. Therefore, it is possible to suppress a decrease in the adsorption force of the fuel vapor in the entire stacked portion 50, and to shorten L of the stacked portion 50. As a result, the fuel vapor released from the second main adsorption chamber 30 can be well retained in the stacked portion 50, and the fuel vapor adsorbed in the adsorbent of the auxiliary adsorption chamber 40 can be removed with a small purge amount.

[0058] Furthermore, since L / D of stacked portion 50 is small, ventilation resistance of air flowing from the fuel tank during refueling can be suppressed when passing through evaporated fuel processing device 1. Furthermore, since L of stacked portion 50 is small, evaporated fuel processing device 1 can be miniaturized.

[0059] [2. Other embodiments]

[0060] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments and can be implemented in various forms.

[0061] (2a) In the above embodiment, the high desorption layer 60 is exemplified as a structure in which the activated carbon formed into a honeycomb shape is used as the third adsorbent 61. However, as long as the desorption performance of the high desorption layer 60 is better than that of the first adsorption layer and the second adsorption layer, the specific structure of the high desorption layer is not particularly limited. For example, a plurality of thin plate-shaped particles can be used as the third adsorbent. The thickness of the thin plate-shaped particles can be formed to be smaller than that of the first adsorbent 53 and the second adsorbent 54. In addition, an adsorbent formed of a material having a better desorption performance than the first adsorbent and the second adsorbent can be used as the third adsorbent. In addition, the adsorption capacity of the third adsorbent 61 can be greater than that of the first adsorbent 51 and the second adsorbent 52, or smaller than that of the first adsorbent 51 and the second adsorbent 52. In addition, in the above embodiment, the thickness of the wall of the honeycomb structure forming the third adsorbent 61 is not particularly limited, but the wall can have a portion whose thickness is formed to be thinner than that of the first adsorbent 53 and the second adsorbent 54. In other words, the third adsorbent 61 may have a thin plate-shaped portion that is thinner than the first adsorbent 53 and the second adsorbent 54 .

[0062] (2b) In the above embodiment, an example of using activated carbon as the adsorbent is shown. However, a part of the adsorbent or all of the adsorbent may use an adsorbent other than activated carbon. In addition, an example of using pellet-shaped activated carbon as the adsorbent other than the third adsorbent 61 is shown, but the adsorbent may also be in a shape other than this. For example, the activated carbon used as the adsorbent may be one or more blocks of activated carbon formed by integrating a plurality of particles.

[0063] (2c) In the above embodiment, the main adsorption chamber is exemplified as comprising a first main adsorption chamber 20 and a second main adsorption chamber 30 which are connected via a connecting passage 15. However, the main adsorption chamber may also be a structure other than that described above. For example, the main adsorption chamber may be one adsorption chamber, in which case the cover member 14 may not be provided. In addition, the main adsorption chamber may also include three or more adsorption chambers.

[0064] In the above embodiment, the first main adsorption chamber 20 and the second main adsorption chamber 30 are connected to each other through the connecting passage 15 provided in the cover member 14, but the structure of the connecting passage is not limited thereto. For example, the first main adsorption chamber 20 and the second main adsorption chamber 30 may be connected to each other through a tube.

[0065] (2d) In the above embodiment, the secondary adsorption chamber 40 is illustrated as having a structure in which the third adsorption material 61, the first adsorption layer 51, and the second adsorption layer 52 are connected in series. However, the secondary adsorption chamber 40 is not limited to the above structure. For example, a layer other than the first adsorption layer 51 and the second adsorption layer 52 may be provided in the stacking section 50. In this case, it is sufficient to include at least two layers, which correspond to the first adsorption layer relatively close to the main adsorption chamber and the second adsorption layer relatively close to the atmospheric port 13 and having an adsorption performance lower than that of the first adsorption layer. The first adsorption layer and the second adsorption layer may also be arranged non-adjacently. In addition, it may also be configured so that an adsorption layer with an adsorption performance higher than that of the second adsorption layer is not arranged on the side closer to the atmospheric port 13 than the second adsorption layer. In addition, a new adsorption chamber or adsorption layer may be provided before and after the high desorption layer 60 in the flow direction. In addition, a porous member such as a porous plate may be provided between the stacking section 50 and the high desorption layer 60. In addition, the secondary adsorption chamber may also be composed of a plurality of chambers. For example, the stacking unit 50 and the high desorption layer 60 may be arranged in different chambers. Also, the first adsorption layer 51 and the second adsorption layer 52 may be arranged in different chambers.

[0066] In addition, if Figure 2As shown in the evaporated fuel processing device 101, the second main adsorption chamber 30 and the high desorption layer 60 can be connected via a flexible tube 111, and the high desorption layer 60 and the stacking part 50 can also be connected via a flexible tube 112. As described above, more than one tube can be used to achieve communication between chambers. According to the above structure, the position of the evaporated fuel processing device 101 can be flexibly determined.

[0067] (2e) The function of one constituent element in the above-mentioned embodiment may be dispersed into a plurality of constituent elements, or the functions of a plurality of constituent elements may be integrated into a single constituent element. In addition, a portion of the configuration of the above-mentioned embodiment may be omitted. At least a portion of the configuration of the above-mentioned embodiment may be added to the configuration of the above-mentioned other embodiment, or at least a portion of the configuration of the above-mentioned embodiment may be replaced with the configuration of the above-mentioned other embodiment, etc.

Claims

1. An evaporative fuel processing device, comprising an inlet, an outlet, and an atmospheric port, wherein the evaporative fuel processing device is configured to accumulate fuel vapor flowing in from a fuel tank through the inlet, and to cause the accumulated fuel vapor to flow out to an internal combustion engine through the outlet by air flowing in from the atmospheric port, wherein the evaporative fuel processing device is characterized in that it further comprises: a main adsorption chamber connected to the inlet and the outlet and provided with an adsorption material for adsorbing the fuel vapor; and a secondary adsorption chamber connected to the atmospheric port and provided with an adsorption material for adsorbing the fuel vapor, and The auxiliary adsorption chamber has a first adsorption layer, a second adsorption layer, and a high desorption layer. The second adsorption layer is located closer to the atmospheric port than the first adsorption layer, and the second adsorption layer has a lower adsorption performance of the fuel vapor than the first adsorption layer. The high desorption layer is located closer to the main adsorption chamber than the first adsorption layer, and the desorption performance of the fuel vapor of the high desorption layer is better than that of the first adsorption layer and the second adsorption layer. The first adsorption layer and the high desorption layer are arranged to be spaced apart from each other via a tube, The high desorption layer includes activated carbon formed into a honeycomb shape and including a thin plate-shaped portion as the adsorbent. The first adsorption layer and the second adsorption layer include granular or pellet-shaped activated carbon as an adsorption material. The thin plate-shaped portion is thinner than the granular or pellet-shaped activated carbon.

2. The evaporated fuel processing device according to claim 1, characterized in that: The main adsorption chamber includes a first main adsorption chamber and a second main adsorption chamber which are communicated with each other via a communication passage. The first main adsorption chamber and the second main adsorption chamber are arranged such that, when the fuel vapor from the fuel tank flows in, a flow direction of the fuel vapor in the first main adsorption chamber is opposite to the flow direction of the fuel vapor in the second main adsorption chamber, and the first main adsorption chamber and the second main adsorption chamber are arranged in a direction intersecting with the flow direction of the fuel vapor in the first main adsorption chamber.

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