CANISTER

A canister includes a first chamber and a second chamber, an inner wall, a charge port, a purge port, an atmosphere port, and an insulator. An adsorbent is placed in the first chamber and the second chamber. The inner wall is located adjacent to the first chamber and the second chamber, and partitions the first chamber and the second chamber. The insulator is provided to at least one of the first chamber or the second chamber. The insulator is arranged between the adsorbent and the inner wall so as to insulate the adsorbent that is placed in the first chamber or the second chamber, to which the insulator is provided, from the inner wall.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Japanese Patent Application No. 2020-145693 filed on Aug. 31, 2020 with the Japan Patent Office, the entire disclosure of which is incorporated herein by reference.

BACKGROUND

The present disclosure relates to a canister.

There is a known canister to reduce emission to the atmosphere of evaporated fuel that is generated in a fuel tank of a vehicle. In the canister, an adsorbent (such as activated carbon) for evaporated fuel is placed, and evaporated fuel flowing from a fuel tank into the canister through a charge port is adsorbed by the adsorbent. Also, in the canister, purge is performed to discharge the evaporated fuel adsorbed by the adsorbent toward an engine. Specifically, by causing the atmosphere to flow into the canister through an atmosphere port using an intake air negative pressure of the engine, the evaporated fuel adsorbed by the adsorbent is desorbed, and the desorbed evaporated fuel is supplied to the engine through a purge port.

As disclosed in Japanese Patent No. 4589422, there is also a known canister that comprises a first chamber provided with a charge port and a purge port, and a second chamber provided with an atmosphere port. By providing the second chamber, an improved adsorption performance for evaporated fuel can be achieved.

SUMMARY

When evaporated fuel is adsorbed by an adsorbent, an exothermic reaction is caused, and an increase in temperature of the adsorbent by the exothermic reaction leads to a decrease in adsorption performance of the adsorbent for evaporated fuel. When evaporated fuel is desorbed from the adsorbent, an endothermic reaction is caused, and a decrease in temperature of the adsorbent by the endothermic reaction leads to a decrease in desorption performance of the adsorbent for the evaporated fuel adsorbed by the adsorbent.

Thus, in the canister of Japanese Patent No. 4589422, a clearance is formed between a wall portion surrounding the first chamber and a wall portion surrounding the second chamber. This configuration can reduce temperature increase of the adsorbent in the second chamber caused by the exothermic reaction when the evaporated fuel flowing through the charge port is adsorbed by the adsorbent in the first chamber, and thus can reduce decrease in adsorption performance of the adsorbent in the second chamber. This configuration can also reduce temperature decrease of the adsorbent in the first chamber caused by the endothermic reaction when the evaporated fuel is desorbed from the adsorbent in the second chamber by the atmosphere flowing in through the purge port, and thus can reduce decrease in desorption performance of the adsorbent in the first chamber.

However, providing the clearance between the wall portion of the first chamber and the wall portion of the second chamber results in an increased arrangement space of the canister, and thus may make it difficult to install the canister in a vehicle.

In one aspect of the present disclosure, it is desirable to facilitate installation of a canister in a vehicle while reducing decrease in adsorption performance and desorption performance for evaporated fuel.

One aspect of the present disclosure is a canister including a casing in which an adsorbent to adsorb evaporated fuel generated in a fuel tank of a vehicle is placed. The canister comprises a first chamber and a second chamber, an inner wall, a charge port, a purge port, an atmosphere port, and an insulator. The first chamber and the second chamber are provided in the casing, and an adsorbent is placed in the first chamber and the second chamber. The inner wall is formed as a part of the casing and located adjacent to the first chamber and the second chamber, and the inner wall partitions the first chamber and the second chamber. The charge port is configured to allow the evaporated fuel to flow into the casing, and is provided to the first chamber. The purge port is configured to discharge the evaporated fuel adsorbed by the adsorbent out of the casing, and the purge port is provided to the first chamber. The atmosphere port is configured to allow an atmosphere to flow into the casing, and the atmosphere port is provided to the second chamber. The insulator is provided to at least one of the first chamber or the second chamber. The insulator is arranged between the adsorbent and the inner wall so as to insulate the adsorbent that is placed in the first chamber or the second chamber, to which the insulator is provided, from the inner wall.

With this configuration, since the first and the second chambers are adjacent to the inner wall, and no clearance is formed between these chambers, an arrangement space for a canister can be reduced. Thus, installation of a canister in a vehicle can be facilitated.

Also, by arranging the charge port, the purge port, or the atmosphere port (hereinafter these are collectively referred to as “ports”) in a vicinity of the inner wall, ports can be located in positions that are impossible for a canister with a clearance between the first chamber and the second chamber. This allows more flexible positioning of ports, and facilitates installation of a canister in a vehicle.

Further, in a case where a clearance is formed between the first chamber and the second chamber, there may be restriction on shapes of parts, which are adjacent to the clearance, of the wall portions of the first and second chambers, and thus positioning of ports may be restricted. In contrast, according to the configuration described above, it is possible to determine the shape of the inner wall more flexibly since there is no clearance between the first chamber and the second chamber. This allows more flexible positioning of ports, and facilitates installation of a canister in a vehicle.

Moreover, since the adsorbent is insulated from the inner wall by the insulator in at least one of the first chamber or the second chamber, heat transmission between the adsorbent in the first chamber and the adsorbent in the second chamber can be reduced. Accordingly, if evaporated fuel is adsorbed by the adsorbent in one of the first chamber and the second chamber, and an exothermic reaction is caused, it is possible to inhibit temperature increase in the other chamber and resulting decrease in adsorption performance of the adsorbent in the other chamber. Also, if evaporated fuel is desorbed from the adsorbent in one of the first chamber and the second chamber, and an endothermic reaction is caused, it is possible to inhibit temperature decrease in the other chamber and resulting decrease in desorption performance of the adsorbent in the other chamber.

This facilitates installation of a canister in a vehicle while reducing decrease in adsorption performance and desorption performance for evaporated fuel.

The insulator may form a space between the inner wall and the adsorbent placed in the first chamber or the second chamber, to which the insulator is provided.

According to this configuration, heat transmission between the adsorbent in the first chamber and the adsorbent in the second chamber can be reduced more effectively.

The insulator may be configured as a tubular member such that the adsorbent is placed inside the insulator.

According to this configuration, by changing the size of the insulator, the quantity and an L/D ratio of the adsorbent inside the insulator can be adjusted easily. Here, L means a length of an arrangement area of the adsorbent in a flow direction of evaporated fuel, and D means an equivalent diameter of the arrangement area in a cross-section orthogonal to the flow direction. Thus, by changing the size of the insulator while using the same casing, the quantity and the L/D ratio of the adsorbent in the chamber to which the insulator is provided can be adjusted depending on a type of vehicle. Accordingly, it is possible to achieve commonality of the whole or a part of a casing for a canister to be installed in a plurality of types of vehicles, and to reduce manufacturing costs of the canister.

The insulator may be formed of a material having heat insulating property.

According to this configuration, heat transmission between the adsorbent in the first chamber and the adsorbent in the second chamber can be reduced more effectively.

The insulator may be provided to the second chamber.

According to this configuration, if evaporated fuel flowing through the charge port is adsorbed by the adsorbent and an exothermic reaction is caused in the first chamber, it is possible to inhibit heat transmission to the second chamber and resulting decrease in adsorption performance of the adsorbent in the second chamber. Also, if evaporated fuel is desorbed from the adsorbent by the atmosphere flowing through the atmosphere port, and an endothermic reaction is caused in the second chamber, it is possible to inhibit temperature decrease of the adsorbent in the first chamber and resulting decrease in desorption performance of the adsorbent. Accordingly, decrease in adsorption performance and desorption performance for evaporated fuel can be reduced.

The first chamber and the second chamber may each extend along a first direction, and the first chamber and the second chamber may each comprise a first end of both ends facing each other along the first direction. Also, the charge port and the purge port may be provided at the first end of the first chamber, and the atmosphere port may be provided at the first end of the second chamber. Further, the casing may comprise a first wall portion and a second wall portion facing each other, the first wall portion and the second wall portion may face the first chamber and the second chamber, respectively, and the inner wall may extend from the first wall portion to the second wall portion. Moreover, at least a part of the inner wall may be oblique to a direction along which the first wall portion and the second wall portion face each other, or may be curved in a cross-section orthogonal to the first direction.

According to this configuration, at least a part of the inner wall is oblique to the direction along which the first wall portion and the second wall portion face each other, or curved in the cross-section orthogonal to the first direction. Accordingly, it is possible to arrange ports in positions different from those in the case where the inner wall is parallel to the direction along which the first wall portion and the second wall portion face each other. This allows more flexible positioning of ports, and facilitates installation of a canister in a vehicle.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Embodiments of the present disclosure are not limited to the embodiments described below, but may be in various forms within the technical scope of the present disclosure.

1. OUTLINE OF CANISTER

A canister1of the present embodiment is installed in a vehicle, and adsorbs evaporated fuel generated in a fuel tank of the vehicle, to thereby reduce flow of the evaporated fuel out of the vehicle (seeFIG. 1). Also, the canister1takes in the atmosphere and performs purge, to thereby cause adsorbed evaporated fuel to flow into an engine of the vehicle.

The canister1comprises a first chamber10, a second chamber11, a connection path12, a purge port13, a charge port14, an atmosphere port15, and an activated carbon16(seeFIGS. 1 and 2).

The activated carbon16as an adsorbent of evaporated fuel is placed in the first and the second chambers10,11. Any adsorbent other than the activated carbon16may be placed in the first and the second chambers10,11. The first and the second chambers10,11each extend along a first direction. The first and the second chambers10,11are located side by side along a second direction orthogonal to the first direction. Hereinafter, a direction orthogonal to the first and the second direction is referred to as a third direction. Also, one side facing the first direction is referred to as a first side, and the other side is referred to as a second side.

A filter10A and a filter10B are placed, respectively, on the first side and the second side of the first chamber10, and the activated carbon16of the first chamber10is contained between the filter10A and the filter10B. Adjacent to the second side of the filter10B, a grid10C with multiple holes allowing passage of fluid is placed.

On the other hand, an inner case3(detailed below) containing the activated carbon16is arranged in the second chamber11.

The connection path12communicates the first chamber10and the second chamber11with each other. The connection path12is connected to an end of the first chamber10on the second side and an end of the second chamber11on the second side, and fluid is movable between the first chamber10and the second chamber11through the connection path12.

The charge port14is provided at an end on the first side (in other words, a first end) of the first chamber10, and is connected to a fuel tank of the vehicle through a valve. Evaporated fuel generated from fuel stored in the fuel tank flows into the canister1through the charge port14, and is adsorbed by the activated carbon16in the first and the second chambers10,11. As a result, the evaporated fuel is accumulated in the canister1.

The purge port13is provided at the end on the first side of the first chamber10, and is connected to an intake pipe of the engine of the vehicle through a valve.

The atmosphere port15is provided at an end on the first side (in other words, a first end) of the second chamber11, and communicates with outside of the vehicle.

By causing the atmosphere (hereinafter, “purge air”) to flow into the canister1through the atmosphere port15using an intake air negative pressure of the engine, the aforementioned purge is performed. In the first and the second chambers10,11, the evaporated fuel adsorbed by the activated carbon16is desorbed by the purge air that has flown in, and the desorbed evaporated fuel flows out through the purge port13toward the intake pipe. As a result, the evaporated fuel adsorbed by the activated carbon16is removed, and the activated carbon16is regenerated.

The canister1also comprises a casing2and a lid4, and these portions form the first chamber10, the second chamber11, and the connection path12. Descriptions will be given of the casing2and the lid4, as well as the aforementioned inner case3.

The casing2is a portion having a generally parallelepiped shape and made of resin, for example. The first and the second chambers10,11are provided in the casing2. The casing2comprises an outer wall20, an inner wall21, and first to third bottom portions22to24(seeFIGS. 1, 2).

The outer wall20is a wall-like portion surrounding the first and the second chambers10,11. The outer wall20comprises first and second wall portions20A,20B facing the first and the second chambers10,11. The first wall portion20A and the second wall portion20B face each other along the third direction. In the present embodiment, by way of example, the first and the second wall portions20A,20B each extend substantially flat along the second direction. However, the first and the second wall portions20A,20B may be oblique to the second direction or may be curved. Also, the outer wall20comprises a third wall portion20C facing the first chamber10and a fourth wall portion20D facing the second chamber11. The third wall portion20C and the fourth wall portion20D face each other along the second direction. In the present embodiment, by way of example, the third and the fourth wall portions20C,20D each extend substantially flat along the third direction. However, the third and the fourth wall portions20C,20D may be oblique to the third direction or may be curved.

The inner wall21is arranged inside the outer wall20to partition an inner space of the outer wall20into the first chamber10and the second chamber11. The inner wall21extends from an inner peripheral surface of the first wall portion20A to an inner peripheral surface of the second wall portion20B, and is adjacent to the first and the second chambers10,11. Also, the inner wall21extends flat and obliquely to the third direction.

The inner wall21may, for example, extend flat along the third direction (seeFIG. 3). Also, the inner wall21may have a curved shape in a cross-section orthogonal to the first direction (seeFIG. 4). Further, a part of the inner wall21may be oblique to the third direction, or may have a curved shape in a cross-section orthogonal to the first direction.

The first and second bottom portions22,23are provided so as to cover an end of the first chamber10on the first side. The first bottom portion22comprises the purge port13, and the second bottom portion23comprises the charge port14.

A third bottom portion24is provided so as to cover an end of the second chamber11on the first side. The third bottom portion24comprises the atmosphere port15.

The purge port13, the charge port14, and the atmosphere port15may be positioned appropriately, and these ports may be arranged in a vicinity of the inner wall21. Arranging a port in the vicinity of the inner wall21may include an arrangement of the port such that, when the port is moved along the first direction toward the second side, the port is positioned to abut or become close to the inner wall21. Specifically, the purge port13or the charge port14may be arranged in any of positions10A to10C inFIGS. 2 to 4, and the atmosphere port15may be arranged in any of positions11A to11C.

3. INNER CASE

The inner case3is configured to contain the activated carbon16, and is arranged in the second chamber11(seeFIG. 1). The inner case3comprises a main body30, a seal member31, filters32,33, a grid34, and a partition wall plate35.

The main body30is a cylindrical portion, and is arranged in the second chamber11so as to extend along the first direction. The main body30is not limited to a cylindrical shape but may be formed as a tubular member having various shapes. Specifically, for example, a cross-section of the main body30orthogonal to the first direction may be a polygon.

The activated carbon16is placed inside the main body30, and a part of the main body30is located between the activated carbon16and the inner wall21. The filters32,33are arranged on the first side and the second side, respectively, of the activated carbon16. The partition wall plate35having multiple holes that allow passage of fluid is arranged adjacent to the first side of the filter32. The grid34having multiple holes that allow passage of fluid is arranged adjacent to the second side of the filter33. The partition wall plate35is arranged a specified distance apart from an opening of the main body30on the first side, and the grid34is arranged a specified distance apart from an opening of the main body30on the second side.

An abutting portion30A is provided at an end of the main body30on the first side, and an opening portion30B and a flange portion30C are provided at an end of the main body30on the second side.

The abutting portion30A forms a rim surrounding the opening of the main body30on the first side, and protrudes outward, and an outer periphery of the abutting portion30A protrudes toward the first side. The abutting portion30A abuts the casing2at the end of the main body30on the first side. Specifically, the abutting portion30A abuts a stepped portion provided at the end of the second chamber11on the first side in the casing2.

The opening portion30B includes the end of the main body30on the second side, and has a diameter increasing toward the second side. The flange portion30C surrounds the opening of the main body30on the second side, and protrudes outward. An outer-circumferential surface of the flange portion30C comprises a groove surrounding the opening of the main body30on the second side, and the seal member31(for example, an O-ring) is placed in the groove.

In the inner case3arranged in the second chamber11, the abutting portion30A, the flange portion30C, and the seal member31abut the casing2, while a space36is formed between a part of the main body30except for the abutting portion30A and the flange portion30C, and each of the outer wall20and the inner wall21. The space36surrounds the main body30extending over an entire arrangement area of the activated carbon16. Thus, the space36is located between the entire arrangement area of the activated carbon16and the inner wall21, and the activated carbon16in the second chamber11is insulated from the inner wall21of the casing2. In the space36, a heat insulating material, such as glass wool, may be placed. Also, the main body30may be formed of a material having heat insulating property.

An end of the space36on the first side abuts the abutting portion30A, and an end of the space36on the second side is sealed by the seal member31provided in the flange portion30C. This configuration inhibits evaporated fuel inside the canister1from flowing into the space36.

The lid4is provided to cover the respective ends of the first and the second chambers10,11on the second side, which are formed by the outer wall20(seeFIG. 1). The aforementioned connection path12is formed between the lid4and the respective ends of the first and the second chambers10,11on the second side. Also, the lid4comprises first and second springs40,41.

The first springs40are provided between an inner peripheral surface of the lid4and the grid10C provided on the second side of the first chamber10, and the first springs40bias the grid10C toward the first side.

The second springs41are provided between the inner peripheral surface of the lid4and the grid34in the inner case3of the second chamber10, and the second springs41bias the grid34toward the first side.

5. MANUFACTURING PROCESS OF CASING

A manufacturing process of the outer wall20in the casing2of the canister1comprises a first process and a second process described below.

In the first process, a first and a second metal molds50,51for forming an outer peripheral surface of the outer wall20of the casing2are placed to face each other (seeFIG. 5).

In the subsequent second process, resin in a molten state is injected between the first metal mold50and the second metal mold51, and the resin is cured. When curing of the resin is completed, the first and the second metal molds50,51are separated from each other. As a result, the outer peripheral surface of the outer wall20is formed. Directions52in which the first and the second metal molds50,51are displaced when the first and the second metal molds50,51are separated from each other in the second process are parallel to the third direction for the outer wall20of the casing2located in the first and the second metal molds50,51.

Outer peripheral surfaces of the first to the third bottom portions22to24, the purge port13, the charge port14, and the atmosphere port15may be formed using the first and the second metal molds50,51in the first and the second processes. Also, the inner peripheral surface of the outer wall20and the inner wall21may be formed using another metal mold that is placed between the first metal mold50and the second metal mold51.

(1) According to the embodiment described above, the first and the second chambers10,11are adjacent to the inner wall21, and there is no clearance between these chambers; thus, an arrangement space for the canister1can be reduced. This facilitates installation of the canister1in a vehicle.

Also, by arranging ports in the vicinity of the inner wall21, ports can be located in positions that are impossible for a canister with a clearance between the first chamber and the second chamber. This allows more flexible positioning of ports, and facilitates installation of a canister in a vehicle.

Further, in a case where a clearance is formed between the first chamber and the second chamber, there may be restrictions on shapes of parts, which are adjacent to the clearance, of the wall portions of the first and the second chambers. Specifically as shown inFIG. 6, in a case where a clearance is formed between a wall portion61of a first chamber60and a wall portion63of a second chamber62in a casing6, it is required to provide projections73,74for forming outer peripheral surfaces of the wall portions61,63to metal molds70,71for forming an outer peripheral surface of the casing6. Thus, if the wall portions61,63are, for example, oblique to separating directions72as shown inFIG. 6, or the wall portions61,63are curved, then the metal molds70,71cannot be displaced in the separating directions72. The separating directions72here mean directions of separating the metal mold70and the metal mold71from each other after curing of resin injected inside the metal molds70,71for forming the casing6. Accordingly, the wall portion61of the first chamber60and the wall portion63of the second chamber62are required to be parallel to the separating directions72, and thus, positioning of ports in the first and the second chambers60,62might be restricted.

In contrast, according to the embodiment described above, it is possible to determine the shape of the inner wall21flexibly since there is no clearance between the first chamber10and the second chamber11. This allows more flexible positioning of ports, and facilitates installation of a canister in a vehicle.

Moreover, in the second chamber11, the inner case3insulates the activated carbon16from an entire area of the inner wall21, and thus, heat transmission can be reduced between the activated carbon16in the first chamber10and the activated carbon16in the second chamber11. Accordingly, if evaporated fuel flowing through the charge port14is adsorbed by the activated carbon16in the first chamber10, and an exothermic reaction is caused, it is possible to inhibit heat transmission to the second chamber11and resulting decrease in adsorption performance of the activated carbon16in the second chamber11. Also, if evaporated fuel is desorbed from the activated carbon16in the second chamber11by the atmosphere that has flown through the atmosphere port15, and an endothermic reaction is caused, it is possible to inhibit temperature decrease of the activated carbon16in the first chamber10and resulting decrease in desorption performance of the activated carbon16.

This facilitates installation of the canister1in a vehicle while reducing decrease in adsorption performance and desorption performance for evaporated fuel.

(2) In the second chamber11, the inner case3provides the space36between the activated carbon16and the inner wall21. Accordingly, heat transmission between the activated carbon16in the first chamber10and the activated carbon16in the second chamber11can be reduced more effectively.

(3) In the second chamber11, the activated carbon16is contained in the main body30of the inner case3. Thus, by changing the size of the main body30, the quantity and the L/D ratio of the activated carbon16in the second chamber11can be easily adjusted. Also, by changing the size of the main body30while using the same casing, the quantity and the L/D ratio of the activated carbon16in the second chamber11can be adjusted depending on a type of vehicle. Accordingly, it is possible to achieve commonality of the whole or a part of the casing2for the canister1to be installed in a plurality of types of vehicles, and to reduce manufacturing costs of the canister1.

(4) The inner wall21is oblique to the third direction along which the first wall portion20A and the second wall portion20B face each other. Accordingly, it is possible to arrange ports in positions different from those in the case where the inner wall21is parallel to the third direction. This allows more flexible positioning of ports, and facilitates installation of the canister1in a vehicle.

7. OTHER EMBODIMENTS

(1) In the embodiment described above, the activated carbon16is contained in the main body30of the inner case3in the second chamber11, and thus the space36is formed between the activated carbon16and each of the inner wall21and the outer wall20. However, the inner case3may be configured, for example, such that the main body30abuts the inner wall21and the outer wall20, leaving no space between the activated carbon16and an inside wall of the second chamber11. In this case, it is preferable to form the main body30of a material having heat insulating property. Such configuration can also achieve the similar effects.

(2) In place of the inner case3, a plate-shaped insulator may be arranged between the activated carbon16in the second chamber11and the inner wall21, to thereby contain the activated carbon16between the outer wall20and the insulator, and insulate the activated carbon16from the entire area of the inner wall21. In this case, a space may be formed between the insulator and the inner wall21, and also a heat insulating material, such as glass wool, may be placed in the space. Alternatively, the insulator may be configured to abut the inner wall21. In this case, it is preferable to form the insulator of a material having heat insulating property. Such configuration can also achieve the similar effects.

(3) The inner case in the embodiment described above may be configured in a shape corresponding to the first chamber10. Then, such inner case containing activated carbon in a similar manner as in the embodiment described above, or other embodiment (1) above, may be arranged in the first chamber10. Further, the insulator in other embodiment (2) above may be configured in a shape suitable for the first chamber10. Then, such insulator may be arranged in the first chamber10, to thereby contain the activated carbon16between the insulator and the outer wall20, and insulate the activated carbon16in the first chamber10from the entire area of the inner wall21.

In this case, the inner case3or the insulator may also be provided in the second chamber11, or the activated carbon16may be contained in the second chamber11without using the inner case3or the insulator. Such configuration can also achieve the similar effects.

(4) In the embodiment described above, the second chamber11may be configured by two or more chambers aligned in the first direction. In this case, it may be configured such that the activated carbon is insulated from the entire area of the inner wall21in each of the chambers in a similar manner as in the embodiment described above, other embodiment (1), or other embodiment (2). Such configuration can also achieve the similar effects.

(5) In the embodiment described above, the abutting portion30A provided at the end of the main body30on the first side may be configured as a flange-like portion protruding outward. Such configuration can also achieve the similar effects.

(6) A plurality of functions performed by a single element in the aforementioned embodiments may be achieved by a plurality of elements, or a function performed by a single element may be achieved by a plurality of elements. Also, a plurality of functions performed by a plurality of elements may be achieved by a single element, or a function performed by a plurality of elements may be achieved by a single element. Further, a part of a configuration in the aforementioned embodiments may be omitted. Moreover, at least a part of a configuration in the aforementioned embodiments may be added to, or may replace, another configuration in the aforementioned embodiments.

8. CORRESPONDENCE OF TERMS

The main body30of the inner case3in the aforementioned embodiments corresponds to one example of an insulator.