Patent ID: 12247531

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.

1. First Embodiment

(1) Configuration of Canister

A canister1according to a first embodiment is a device that is mounted in a vehicle and that adsorbs and desorbs fuel vapor generated in a fuel tank from which fuel is supplied to an engine of the vehicle (seeFIG.1).

The canister1comprises an inflow port2, an outflow port3, an atmosphere port4, a first adsorption chamber10, a second adsorption chamber20, a third adsorption chamber30, and a connection passage5.

The inflow port2is coupled to a fuel tank by a pipe. The inflow port2is configured to take the generated fuel vapor from the fuel tank into the canister1.

The outflow port3is coupled to an intake pipe of the engine through a not-shown purge valve. The outflow port3is configured to allow the fuel vapor accumulated in each adsorption chamber of the canister1to be discharged toward the engine during purging.

The atmosphere port4is open to atmospheric air. In other words, the atmosphere port4communicates with an outside of the vehicle and is configured to release, to atmospheric air, an air from which the fuel vapor is removed. In addition, the atmosphere port4allows an atmospheric air (hereinafter, a purge air) to be taken in during the purging. The purge air flows downstream within the canister1, thereby removing the fuel vapor adsorbed on an adsorbent of each adsorption chamber within the canister1, and the removed fuel vapor is discharged through the outflow port3.

The inflow port2and the outflow port3are provided at one end of a flow path P for the fuel vapor and the purge air (collectively also referred to as a “fluid”) within the canister1. In contrast, the atmosphere port4is provided at the other end of the flow path P opposite to the inflow port2and the outflow port3. A direction of the flow path P corresponds to a flow direction of the fluid within the canister1.

Inside the canister1, a second adsorption chamber20, a first adsorption chamber10, and a third adsorption chamber30are arranged in order from the atmosphere port4along the flow path P. The atmosphere port4is adjacent to the second adsorption chamber20. The inflow port2and the outflow port3are adjacent to the third adsorption chamber30.

The first adsorption chamber10and the second adsorption chamber20are aligned in a straight line, and the flow path Pin the first and second adsorption chambers10and20extends linearly. In contrast, the first adsorption chamber10and the third adsorption chamber30are arranged to be folded back via a connection passage5, and the flow path P in the first and third adsorption chambers10and30is folded back into a U shape. It is noted that the first to third adsorption chambers10to30are not limited, and the first to third adsorption chambers10to30may be aligned in a straight line, and the flow path P may extend linearly from end to end.

The third adsorption chamber30is a main chamber having a maximum volume among the adsorption chambers. In the third adsorption chamber30, a third adsorbent31to adsorb the fuel vapor is located. Examples of the third adsorbent31include activated carbon, more specifically, powdery activated carbon, granular activated carbon, activated carbon having a honeycomb-shape structure, and fibrous activated carbon that formed into a sheet shape, a rectangular prism shape, a circular cylindrical shape, a polygonal column shape, or the like.

In contrast, the first adsorption chamber10and the second adsorption chamber20are subsidiary chambers each having a smaller volume than the third adsorption chamber30serving as a main chamber. Inside the first adsorption chamber10, a first adsorbent11similar to the third adsorbent31is arranged. However, the second adsorption chamber20is configured as a specific chamber. In the second adsorption chamber20, a second adsorbent serving as an adsorbent agglomerate6is arranged.

(2) Adsorbent Agglomerate

The adsorbent agglomerate6is configured to adsorb the fuel vapor. As an example, the adsorbent agglomerate6is a felt-like mass of fibrous activated carbon (seeFIGS.1to3). The adsorbent agglomerate6is formed, as an example, by solidifying fibrous activated carbon with binders or the like. Alternatively, the fibrous activated carbon may be formed, for example, by carbonizing fibrous materials such as nonwoven fabric. The adsorbent agglomerate6may be also formed by solidifying fibrous adsorbents other than activated carbon.

The adsorbent agglomerate6is formed, as an example, into a circular cylindrical shape extending along an axial line A. A length of the adsorbent agglomerate6in a direction of the axial line A is shorter than a diameter (i.e., width) of a circular cross section (hereinafter, also simply referred to as a “cross section”) orthogonal to the axial line A. It is noted that the axial line A passes through the center of the cross section of the adsorbent agglomerate6. The shape of the adsorbent agglomerate6is not limited to the circular cylindrical shape, and may be, for example, a rectangular column shape having a shorter length in the direction of the axial line A than a width thereof.

The adsorbent agglomerate6is arranged in the second adsorption chamber20such that the direction of the axial line A coincides with the direction of the flow path P (i.e., a flow direction of the fluid). In addition, the adsorbent agglomerate6includes a first surface60and a second surface61, which are formed at both ends on its outer surface of the adsorbent agglomerate6in the direction of the axial line A. The first surface60and the second surface61intersect with the direction of the flow path P, as an example, at an angle of approximately 90°, and the second surface61is positioned on a side opposite to the first surface60.

The second surface61is located on a side where the atmosphere port4is arranged (i.e., side of the atmosphere port4) in the flow direction of the fluid, and the first surface60is located on a side where the inflow port2and the outflow port3are arranged (i.e., side of the first adsorption chamber10). That is, a distance from the first surface60to the atmosphere port4along the flow direction of the fluid is longer than a distance from the second surface61to the atmosphere port4along the flow direction of the fluid. In other words, the second surface61is located closer to the atmosphere port4than the first surface60is, and a minimum distance to the port from the first surface60is longer than the minimum distance to the port from the second surface61. The minimum distance to the port means a shorter distance of a distance from the first surface60to the atmosphere port4along the flow direction of the fluid and a distance from the first surface60to the inflow port2and the outflow port3along the flow direction of the fluid, or of a distance from the second surface61to the atmosphere port4along the flow direction of the fluid and a distance from the second surface61to the inflow port2and the outflow port3along the flow direction of the fluid.

The first surface60includes two or more holes62(i.e., vacant spaces) each formed to extend in a direction substantially coincident with the direction of the axial line A (i.e., flow direction of the fluid) (seeFIGS.2and3). As an example, the holes62have depths substantially identical to each other, and have respective bottoms63. Each bottom63is located substantially in a middle of the adsorbent agglomerate6in the direction of the axial line A. Each hole62does not penetrate through the adsorbent agglomerate6. In contrast, the second surface61does not include a hole.

As an example, each hole62has a circular cylindrical shape, but is not limited to this shape. The shape of each hole62may be determined as appropriate. The holes62have substantially identical diameters (i.e., a dimension of each hole62) (as an example, an approximately 2 mm diameter) to each other in the respective cross sections.

In addition, as an example, the holes62are arranged throughout the first surface60such that each hole62is spaced from another hole62adjacent to the hole62with a substantially constant spacing. Preferably, the distance between two adjacent holes62is greater than the diameter (i.e., width) of each hole62.

The holes62may be formed, for example, by using a mold in a molding process of the adsorbent agglomerate6, or by making a hole in the first surface60after the adsorbent agglomerate6is molded.

(3) Modified Examples of Adsorbent Agglomerate

(1) First Modified Example

The holes62in the first surface60may vary in depth. Specifically, as shown inFIG.4, the holes62may be deeper from the center of the first surface60toward its rim. Typically, a flow of fluid concentrates on the center in its flow path, and a flow velocity of fluid decreases toward an edge of the flow path. Thus, by making the holes62deeper from the center of the first surface60to the rim, a flow of the fluid passing through the adsorbent agglomerate6can be encouraged in a suitable manner.

Alternatively, for example, the adsorbent agglomerate6may include no hole in the first surface60, but include the holes62in the second surface61in a similar manner.

Alternatively, the holes62may be formed in each of the first surface60and second surface61of the adsorbent agglomerate6, similarly to the embodiment described above.

Specifically, for example, as shown inFIG.5, the holes62in the first surface60and the holes62in the second surface61may be arranged such that the bottom63of each hole62in the first surface60and the bottom63of each hole62in the second surface61face each other in the direction of the axial line A. In other words, when the adsorbent agglomerate6is viewed in the direction of the axial line A, the holes62in the first surface60and the holes62in the second surface61may be arranged so as to overlap. Accordingly, a ventilation resistance of the adsorbent agglomerate6can be reduced.

Alternatively, for example, as shown inFIG.6, the holes62in the first surface60and the holes62in the second surface61may be arranged such that the bottom63of each hole62in the first surface60and the bottom63of each hole62in the second surface61do not face each other in the direction of the axial line A. In other words, when viewed in the direction of the axial line A, the holes62in the first surface60and the holes62in the second surface61may be arranged so as not to overlap. Accordingly, it is possible to ensure a distance to allow the fuel vapor to move while in contact with the adsorbent agglomerate6when the fuel vapor passes through the adsorbent agglomerate6, thus encouraging the fuel vapor to be adsorbed into the adsorbent agglomerate6.

(2) Second Modified Example

The holes62may be formed in any specific location on the first surface60and/or second surface61of the adsorbent agglomerate6, rather than throughout the first surface60and/or second surface61of the adsorbent agglomerate6.

Specifically, the holes62may be formed in an area, for example, where the flow of the fluid is stagnant. In an example, as shown inFIG.7, the holes62may be arranged along an outer circumference of the first surface60in a row so as to be aligned from each other at a substantially constant spacing. Alternatively, for example, as shown inFIG.8, the first surface60may be divided in two semicircular areas, and the holes62may be formed throughout one of the two semicircular areas.

Alternatively, the holes62formed in the first surface60and/or the second surface61may vary in diameter (i.e., dimension). Specifically, for example, as shown inFIG.9, the holes62may be enlarged from the center of the first surface60toward its outer circumference. As described above, the flow velocity of the fluid decreases toward the edge of the flow path. Thus, by enlarging the holes62from the center of the first surface60toward its outer circumference, it is possible to encourage the fluid passing through the adsorbent agglomerate6to flow in a suitable manner.

Alternatively, one hole62may be formed in the first surface60and/or the second surface61.

2. Second Embodiment

(1) Adsorbent Agglomerate

The canister1according to a second embodiment differs from that according to the first embodiment in a configuration of an adsorbent agglomerate7, which is a second adsorbent arranged in the second adsorption chamber20. The following describes a difference in the configuration of the adsorbent agglomerate7from the first embodiment.

The adsorbent agglomerate7comprises a main body72and two or more first projections73(seeFIGS.10and11).

The main body72has, as an example, a circular cylindrical shape extending along the axial line A, and a length of the main body72in the direction of the axial line A is shorter than a diameter of a cross section (i.e., width) of the main body72. It is noted that the axial line A passes through the center of the cross section of the main body72. The shape of the main body72is not limited to a circular cylindrical shape, and may be a rectangular column shape having a shorter length along the axial line A than its width, for example.

The first projections73each are a portion having a circular cylindrical shape and protruding in the direction of the axial line A from an end portion of the main body72in the direction of the axial line A. Each first projection73has an identical or similar height. The first projections73have tips forming a first surface70of the adsorbent agglomerate7. In addition, each first projection73is tapered toward its tip, thereby making it easier to detach a mold from the first projections73in a molding process of the adsorbent agglomerate7.

The first projections73are provided close to each other. At least one interspace between adjacent first projections73forms at least one vacant space74. The at least one vacant space74extends from the first surface70in the direction of the axial line A (i.e., flow direction of the fluid) and spreads throughout the first surface70. The at least one vacant space74reaches the main body72or a portion in the vicinity of the main body72(hereinafter, a bottom of the main body72). In other words, the bottom of the at least one vacant space74corresponds to a portion in the vicinity of base portions of the first projections73on the adsorbent agglomerate7. The interspace between the first projections73may form a continuous single vacant space74, or may form two or more vacant spaces74that are separate from each other.

On the other end portion of the main body72where the first projections73are not formed, a second surface71is provided. In other words, the second surface71includes no vacant space.

Similarly to the first embodiment, the adsorbent agglomerate7is arranged in the second adsorption chamber20such that the direction of the axial line A coincides with the flow direction of the fluid. In addition, the second surface71is located on the side of the atmosphere port4in the flow direction of the fluid, and the first surface70is located on the side where the inflow port2and the outflow port3are arranged (i.e., side of the first adsorption chamber10). That is, a distance from the first surface70to the atmosphere port4along the flow direction of the fluid is longer than a distance from the second surface71to the atmosphere port4along the flow direction. In other words, a minimum distance to the port from the first surface70is longer than a minimum distance to the port from the second surface71.

The first surface70of the adsorbent agglomerate7may include no vacant space, whereas the second surface71may include at least one vacant space by having two or more projections in a similar manner.

(2) Modified Examples

In the adsorbent agglomerate7in modified examples, the at least one vacant space74is formed in the first surface70, and the at least one vacant space76is formed in the second surface71(seeFIGS.12to15). Specifically, the adsorbent agglomerate7comprises the main body72, the two or more first projections73, and two or more second projections75.

The main body72and the first projections73are configured similarly to the second embodiment.

In contrast, similarly to the first projections73, the second projections75are provided on an end portion of the main body72opposite to the end portion where the first projections73are provided. The second surface71of the adsorbent agglomerate7is formed by tips of the second projections75. Similarly to the first projections73, each second projection75is tapered toward its tip, and at least one interspace between adjacent second projections75forms at least one vacant space76throughout the second surface71.

As shown inFIGS.12and13, each first projection73and each second projection75may be arranged so as to face each other in the direction of the axial line A, in other words, when the adsorbent agglomerate7is viewed in the direction of the axial line A, the first projections73and the second projections75may be arranged so as to overlap each other. Accordingly, since the bottom of the at least one vacant space74on the first surface70and the bottom of the at least one vacant space76in the second surface71are encouraged to overlap in the direction of the axial line A, a ventilation resistance of the adsorbent agglomerate7can be reduced.

Alternatively, as shown inFIGS.14and15, each first projection73and each second projection75may be arranged so as not to face each other in the direction of the axial line A, in other words, when the adsorbent agglomerate7is viewed in the direction of the axial line A, the first projections73and the second projections75may be arranged so as not to overlap each other. The bottom of the at least one vacant space74on the first surface70and the bottom of the at least one vacant space76on the second surface71can be inhibited from overlapping in the direction of the axial line A. Accordingly, it is possible to ensure a distance to allow the fuel vapor to move while in contact with the adsorbent agglomerate7when the fuel vapor passes through the adsorbent agglomerate7, thus encouraging the fuel vapor to be adsorbed into the adsorbent agglomerate7.

3. Effects

(1) In the aforementioned embodiments, the at least one vacant space is provided in the first surface and/or the second surface of the adsorbent agglomerate. Since the at least one vacant space does not to penetrate through the adsorbent agglomerate, the fluid that has entered the second adsorption chamber20is encouraged to pass through the adsorbent agglomerate. Thus, it is possible to reduce a ventilation resistance in the canister1while inhibiting performance of the fuel vapor adsorption from decreasing.

(2) The at least one vacant space is formed throughout the first surface and/or second surface of the adsorbent agglomerate. Thus, it is possible to decrease the ventilation resistance in the canister while inhibiting an uneven flow of the fuel vapor.

(3) By forming the at least one vacant space in only the first surface of the adsorbent agglomerate, it is easier to confirm an orientation of the adsorbent agglomerate. Thus, an operation to arrange the adsorbent agglomerate in the second adsorption chamber20is simpler in a manufacturing process of the canister1.

(4) The first surface of the adsorbent agglomerate including the at least one vacant space is arranged on the side of the first adsorption chamber10, and the second surfaces of the adsorbent agglomerate is arranged on the side of the atmosphere port4. Thus, the fuel vapor can be inhibited from flowing out to an exterior of the canister1through the atmosphere port4.

(5) It is possible to further reduce the ventilation resistance in the canister by providing the at least one vacant space in each of the first and second surfaces of the adsorbent agglomerate.

(6) The adsorbent agglomerate can be arranged in the second adsorption chamber20adjacent to the atmosphere port4. Thus, it is possible to reduce the ventilation resistance in the canister1while inhibiting the fuel vapor from flowing out through the atmosphere port4.

4. Other Embodiments

(1) In the aforementioned embodiments, the adsorbent agglomerate is arranged in the second adsorption chamber20. However, the adsorbent agglomerate may be arranged in the first adsorption chamber10or the third adsorption chamber30such that the direction of the axial line A and the direction of the flow path P substantially coincide with each other. In this case, the adsorbent agglomerate may be formed into a shape corresponding to the first adsorption chamber10or to the third adsorption chamber30, and may be arranged throughout the first adsorption chamber10or the third adsorption chamber30, or may be arranged in a partial region of either the first adsorption chamber10or the third adsorption chamber30.

In this case, as an example, the adsorbent agglomerate including the at least one vacant space (i.e., at least one hole) only in the first surface may be arranged in the first adsorption chamber10such that the second surface is located on the side of the atmosphere port4. As an example, the adsorbent agglomerate may be arranged in the third adsorption chamber30such that the second surface is located on the side of the inflow port2and the outflow port3.

(2) In the aforementioned embodiments, the direction of the axial line A of the adsorbent agglomerate arranged in the second adsorption chamber20is substantially coincident with an alignment direction where the first and second adsorption chambers10and20are aligned, in other words, the direction of the flow path P in the first adsorption chamber10(seeFIG.1). Since the adsorbent agglomerate has a laterally long shape, the second adsorption chamber20protrudes more laterally than the first adsorption chamber10.

However, the adsorbent agglomerate may be arranged in the second adsorption chamber20such that the orientation of the axial line A intersects with the alignment direction of the first and second adsorption chambers10and20at a specific angle (as an example, an angle of 90°). The direction of the flow path P within the second adsorption chamber20may be adjusted as appropriate such that the direction of the axial line A and the direction of a segment of the flow path P in the adsorbent agglomerate through which the fluid passes are substantially coincident. The second adsorption chamber20can be inhibited from protruding laterally, and mountability of the canister1to a vehicle can be improved.

(3) Although the canister1of the aforementioned embodiments comprises the three adsorption chambers10to30, the number of adsorption chambers to be provided in the canister1may be one or two, or four or more. Even in such a case, similarly to the aforementioned embodiments, the adsorbent agglomerate may be arranged in any of the adsorption chambers. The adsorbent agglomerates may be arranged in two or more adsorption chambers within the canister1.

(4) 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 be replaced with another configuration in the above-described embodiments.

5. Technical Ideas Disclosed in the Specification

[Item 1]

A canister configured to be mounted in a vehicle with an engine, the canister comprising:at least one chamber in which an adsorbent to adsorb fuel vapor is arranged;an inflow port configured to allow the fuel vapor to flow into the at least one chamber from a fuel tank of the vehicle;an atmosphere port configured to be open to an atmospheric air;an outflow port configured to allow the fuel vapor adsorbed on the adsorbent to flow out to the engine by the atmospheric air flowing in from the atmosphere port; andan adsorbent agglomerate arranged in a specific chamber, the adsorbent agglomerate being a mass of a fibrous adsorbent, the specific chamber being one of the at least one chamber,the adsorbent agglomerate including, on its outer surface, first and second surfaces intersecting with a flow direction of a fluid in the specific chamber, the second surface being positioned on a side opposite to the first surface, andthe adsorbent agglomerate including at least one vacant space formed in the first surface and/or the second surface, the at least one vacant space extending along the flow direction to a bottom located inside the adsorbent agglomerate.
[Item 2]

The canister according to Item 1, wherein the at least one vacant space is formed throughout the first surface and/or the second surface of the adsorbent agglomerate.

[Item 3]

The canister according to Item 1 or Item 2, wherein the at least one vacant space is formed in the first surface of the adsorbent agglomerate and is not formed in the second surface of the adsorbent agglomerate.

[Item 4]

The canister according to Item 3,wherein the at least one chamber comprises a plurality of chambers including:a chamber adjacent to the inflow port and to the outflow port; anda chamber adjacent to the atmosphere port, andwherein a distance from the first surface to the atmosphere port along the flow direction is longer than a distance from the second surface to the atmosphere port along the flow direction.
[Item 5]

The canister according to Item 1 or Item 2, wherein the at least one vacant space is formed in the first and second surfaces of the adsorbent agglomerate.

[Item 6]

The canister according to any one of Item 1 through Item 5,wherein the at least one chamber comprises, as the specific chamber, the chamber adjacent to the atmosphere port.