Evaporative emissions canister with adsorbent volume ratio

Abstract

An evaporative emissions canister (10) is provided and includes a casing (12) defining an internal volume therein. The casing includes a charge port (18) in fluid communication with the internal volume. The internal volume is partitioned into a plurality of chambers including a first chamber (14) and a separate second chamber (16). The first chamber is adjacent to the charge port. The first chamber has a first volume, and the second chamber has a second volume smaller than the first volume. A first bed of adsorbent material (30) is disposed in the first chamber. A second bed of adsorbent material (32) is disposed in the second chamber. A ratio of the first volume of the first chamber to the second volume of the second chamber is in a range of 85:15 to 90:10. A ratio of a length of the second chamber to a diameter of the second chamber is less than or equal to 1.

Description

Atty Docket No.200451.216711-WO (PH24052) EVAPORATIVE EMISSIONS CANISTER WITH ADSORBENT VOLUME RATIO CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Application No. 63 / 690,098, filed September 3, 2024, the disclosure of which is incorporated by reference in its entirety. FIELD OF THE INVENTION

[0002] The disclosure generally relates to evaporative emissions canisters for adsorption of fuel vapors generated in fuel storage tanks of fuel-powered vehicles. BACKGROUND OF THE INVENTION

[0003] Evaporative loss of fuel vapor generated within fuel tanks of the fuel systems of motor vehicles powered by internal combustion engines is a potential contributor to atmospheric air pollution by hydrocarbons. Canister systems that employ activated carbon to adsorb the fuel vapor emitted from the fuel systems are used to limit such evaporative emissions from the fuel tanks of gasoline-fueled automotive vehicles. A typical evaporative emissions canister includes a casing inside of which a gas passage is formed and filled with an activated carbon or other similar adsorbent as a fuel vapor adsorbent. Charge and purge ports for fuel vapor are communicated with one end of the gas passage, while an atmospheric port (vent port) for fuel vapor is communicated with the other end of the gas passage, thus allowing for charging of the canister. During stoppage of the vehicle (e.g., when parked), fuel vapor generated from the fuel in the fuel tank is introduced through the charge port into the canister and adsorbed by the adsorbent. During operation of the engine, atmospheric air is introduced through the atmospheric vent port to purge the fuel vapor in the canister by desorbing fuel vapor that was adsorbed in the adsorbent. The flow of air carries the purged fuel vapor to an intake system of the engine through the purge port so that the fuel vapor can be combusted within the engine, thus accomplishing a purging of the canister. By the desorption of fuel vapor during purging, the carbon adsorbent is regenerated and a fuel vapor adsorbing performance of the canister is revived, thereby allowing the adsorbent to repeatedly adsorb fuel vapor during periods of non-use of the engine.

[0004] Bleed emissions from such canister systems are generally in the form of fuel vapors that are not adsorbed within the canister and undesirably escape to the external atmosphere through the vent port of the canister. To reduce fuel vapor emissions in the form of bleed from the canister, a monolithic honeycomb adsorbent structure is conventionally disposed within the canister downstream from the activated carbon adsorbent and near the vent port to trap remaining fuel vapors that were not adsorbed by the activated carbon adsorbent. These monolithic honeycomb structures are effective to adsorb a significant portion of the remaining fuel vapors before they can escape from the canister. The monolithic honeycomb structures also offer a low flow restriction and fuel vapors are more easily desorbed from theAtty Docket No.200451.216711-WO (PH24052) monolithic honeycomb structure during purging of the canister. Monolithic honeycomb structures, however, are costly to produce and therefore not economical.

[0005] Further, as shown by example in Figure 1, in order to keep bleed emissions at a low level, conventional canisters are made to have a first volume of adsorbent at the charge side of the canister that represents 60% to 70% (commonly 67%), and at most 80% of the total volume of adsorbent in the canister, and a second volume of adsorbent at the vent side of the canister that represents the remainder of the total volume of adsorbent, namely 30% to 40% (commonly 33%), and at the smallest 20% of the total volume of adsorbent. In addition, to avoid high flow restriction, the second volume of adsorbent has a length (height) to diameter ratio that is in the range of 3 to 5. For example, a typical length to diameter ratio is 3.5. Thus, conventional canisters have a slim design. While these canister configurations may reduce bleed emissions, the gross bleed emissions from these canisters are still at too high of a level and thus require the addition of a fine filter such as the monolithic honeycomb structure described.

[0006] A continued need exists for a evaporative emissions canister that limits bleed emissions, has a low flow restriction, and / or that is less costly to produce. BRIEF SUMMARY

[0007] An improved evaporative emissions canister is provided. The evaporative emissions canister includes a casing defining an internal volume therein. The casing includes a charge port and a vent port in fluid communication with the internal volume. The internal volume is partitioned into a plurality of chambers including a first chamber and a separate second chamber. The first chamber is adjacent to the charge port. The first chamber has a first volume, and the second chamber has a second volume that is smaller than the first volume. A first bed of adsorbent material is disposed in the first chamber. A second bed of adsorbent material is disposed in the second chamber. A ratio of the first volume of the first chamber to the second volume of the second chamber is in a range of 85:15 to 90:10.

[0008] In specific embodiments, the first bed of adsorbent material constitutes 85% to 90% of a total volume of adsorbent material contained within the internal volume of the canister.

[0009] In specific embodiments, the second bed of adsorbent material constitutes 10% to 15% of a total volume of adsorbent material contained within the internal volume of the canister.

[0010] In specific embodiments, a ratio (L / D) of a length of the second chamber to a diameter of the second chamber is less than or equal to 1.

[0011] In specific embodiments, the second chamber is in series with the first chamber.

[0012] In specific embodiments, the second chamber is farther from the charge port than the first chamber.Atty Docket No.200451.216711-WO (PH24052)

[0013] In specific embodiments, the second chamber is closer to the vent port than the first chamber.

[0014] In specific embodiments, the second chamber is downstream from first chamber in a charging flow direction through the internal volume of the canister.

[0015] In specific embodiments, the second bed of adsorbent material is a last volume of adsorbent material in a charging flow direction.

[0016] In specific embodiments, the second chamber is spaced from the first chamber.

[0017] In specific embodiments, further including a purge port, the first chamber being adjacent the purge port.

[0018] A fuel vapor canister for adsorbing fuel evaporated in a fuel tank of a vehicle is also provided. The fuel vapor canister includes a casing defining an internal volume therein. The casing includes a tank port for receiving fuel vapor from the fuel tank into the internal volume. The casing further includes a purge port for delivering fuel vapor from the internal volume to an engine of the vehicle. the casing further includes a vent port for communicating the internal volume with ambient air. The tank port, the purge port, and the vent port are in fluid communication with the internal volume. The internal volume is partitioned into a plurality of chambers including a first chamber and a separate second chamber. The first chamber is adjacent to the tank port. The first chamber has a first volume, and the second chamber has a second volume that is smaller than the first volume. A first bed of adsorbent material is disposed in the first chamber. A second bed of adsorbent material is disposed in the second chamber. A ratio of the first volume of the first chamber to the second volume of the second chamber is in a range of 85:15 to 90:10.

[0019] In specific embodiments, the first bed of adsorbent material constitutes 85% to 90% of a total volume of adsorbent material contained within the internal volume of the canister.

[0020] In specific embodiments, the second bed of adsorbent material constitutes 10% to 15% of a total volume of adsorbent material contained within the internal volume of the canister.

[0021] In specific embodiments, a ratio (L / D) of a length of the second chamber to a diameter of the second chamber is less than or equal to 1.

[0022] In specific embodiments, a fluid flow path extends through the internal volume of the canister. The fluid flow path extends from the tank port to the vent port in a charging flow direction.

[0023] In particular embodiments, the second chamber is downstream from first chamber along the fluid flow path in the charging flow direction.

[0024] In particular embodiments, the second chamber is spaced from the first chamber along the fluid flow path.Atty Docket No.200451.216711-WO (PH24052)

[0025] In particular embodiments, the second bed of adsorbent material is in direct series with the first bed of adsorbent material along the fluid flow path such that no other bed of adsorbent material is between the first bed of adsorbent material and the second bed of adsorbent material along the fluid flow path.

[0026] A method of making an evaporative emissions canister is also provided. The method includes forming a casing defining an internal volume therein, the casing including a charge port and a vent port in fluid communication with the internal volume, wherein the internal volume is partitioned into a plurality of chambers including a first chamber and a separate second chamber, the first chamber being adjacent to the charge port, the first chamber having a first volume, the second chamber having a second volume that is smaller than the first volume, and a ratio of the first volume of the first chamber to the second volume of the second chamber is in a range of 85:15 to 90:10. The method further includes disposing a first bed of adsorbent material in the first chamber. The method further includes disposing a second bed of adsorbent material in the second chamber.

[0027] In specific embodiments of the method, the first bed of adsorbent material constitutes 85% to 90% of a total volume of adsorbent material contained within the internal volume of the canister.

[0028] In specific embodiments of the method, the second bed of adsorbent material constitutes 10% to 15% of a total volume of adsorbent material contained within the internal volume of the canister.

[0029] In specific embodiments of the method, a ratio (L / D) of a length of the second chamber to a diameter of the second chamber is less than or equal to 1. DESCRIPTION OF THE DRAWINGS

[0030] Various advantages and aspects of this disclosure may be understood in view of the following detailed description when considered in connection with the accompanying drawings, wherein:

[0031] Figure 1 is a schematic view of an evaporative emissions canister in accordance with the prior art;

[0032] Figure 2 is a schematic view of an evaporative emissions canister in accordance with embodiments of the disclosure;

[0033] Figure 3 is a graph of gross bleed and flow restriction as a function of the volume ratio between a first canister chamber and a second canister chamber with the ratio of length to diameter of the second canister chamber set at a value of 1 in accordance with embodiments of the disclosure;

[0034] Figure 4 is a graph of flow restriction as a function of the volume ratio between a first canister chamber and a second canister chamber, for the evaporative emissions canister in accordance with embodiments of the disclosure having a ratio of length to diameter of theAtty Docket No.200451.216711-WO (PH24052) second canister chamber set at a value of 1, and for an evaporative emissions canister in accordance with the prior art having a ratio of length to diameter of the second canister chamber set at a value of 3; and

[0035] Figure 5 is a schematic view of a vehicle including an evaporative emissions canister in accordance with embodiments of the disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0036] An evaporative emissions canister is provided. Referring to Figures 2-5, wherein like numerals indicate corresponding parts throughout the several views, the evaporative emissions canister is illustrated and generally designated as a fuel vapor canister 10 for a fuel tank 40 of a vehicle fuel system that pumps liquid fuel, by way of non-limiting example gasoline fuel, from the fuel tank 40 to an internal combustion engine 42 that powers a vehicle 44 such as an automotive vehicle. The fuel vapor canister 10 traps fuel vapors that arise in the fuel tank 40 during periods of non-use of the internal combustion engine 42 due to, for example, daily variations in ambient temperatures or a refueling event. The fuel vapor canister 10 exhibits improved reduction of bleed emissions while at the same time having low flow restriction through the internal volume of the canister. The fuel vapor canister 10 may also reduce the amount and / or size of a monolithic honeycomb fine filter which may reduce the cost of the canister.

[0037] Figure 2 generally depicts the fuel vapor canister 10 used in a vehicle fuel system. The fuel vapor canister 10 includes a casing 12 that forms a main body of the canister 10. The casing 12 defines an internal volume within the main body. The internal volume is partitioned into a plurality of chambers including a first chamber 14 and a second chamber 16. The casing 12 has at least one inlet and one outlet in fluid communication with the internal volume of the casing 12. Particularly, the casing 12 has a charge port (tank port) 18, a purge port 20, and a vent port 22. The charge port 18 and purge port 20 are disposed at one end of the internal volume of the casing 12 adjacent to the first chamber 14, while the vent port 22 is disposed at an opposite end closer to the second chamber 16 in a fluid flow direction, so that there may be fluid flow between the charge port 18 and the vent port 22 or between the vent port 22 and the purge port 20. In use, the charge port 18 is connected to and in fluid communication with the vehicle fuel tank via a conduit or similar. The charge port 20 is also in fluid communication with the first chamber 14 within the internal volume of the casing 12. The purge port 20 is connected to and in fluid communication with an air intake system of the engine via a conduit or similar. The purge port 20 is also in fluid communication with the first chamber 14 within the internal volume of the casing 12. The vent port 22 is open to the atmosphere for venting the canister 10 and for admission of purge air. The chambers 14, 16 of the casing 12 may be generally box-shaped and have, for example, a generally rectangular cross-section in a direction generally perpendicular to the flow direction.Atty Docket No.200451.216711-WO (PH24052) However, the chambers 14, 16 may instead have any one of a conical, a frustoconical, and / or a cylindrical shape and therefore a generally circular cross-section.

[0038] During non-use of the internal combustion engine when the engine is off, fuel vapors generated in the fuel tank travel through the charge port 18 and into the internal volume of the casing 12. The fuel vapors become trapped in the canister casing 12, and air exits the casing 12 through the vent port 22. During periods of use of the internal combustion engine when the engine is running, air is drawn into the canister 10 through the vent port 22, and the trapped fuel vapors are expelled from the casing 12 through the purge port 20 and into the air intake system of the internal combustion engine. It is therefore apparent that the charge port 18 is an inlet and the purge port 20 is an outlet, while the vent port 22 may be an outlet or an inlet depending on the operation of the canister 10 (charging versus purging) and the associated direction of flow. A fluid flow path thereby extends from the charge port 18 through the internal volume of the casing 12 to the vent port 22 in the charging direction of flow in the charging (adsorption) mode of the canister 10, and from the vent port 22 through the internal volume of the casing 12 to the purge port 20 in a discharging flow direction in the discharging (desorption) mode of the canister 10. The first chamber 14 is considered the “first” chamber because it is the first chamber of the canister 10 in which fuel vapors are introduced during the charging mode and is the first chamber along the fluid flow path in the charging flow direction in relation to the charge port 18. The second chamber 16 is considered the “second” chamber because it is the second chamber in which fuel vapors are introduced during the charging mode and is the second chamber along the fluid flow path in the charging flow direction. As such, the second chamber 16 is downstream from the first chamber 14 in the charging flow direction. Further, the second chamber 16 is closer to the vent port 22 than the first chamber 14, and the second chamber 16 is disposed between the first chamber 14 and the vent port 22 along the fluid flow path through the internal volume of the casing 12. Likewise, the second chamber 16 is farther from the charge port 18 and the purge port 20 than the first chamber 14, and the first chamber 14 is disposed between the second chamber 16 on one side and the charge port 18 and the purge port 22 on another side along the fluid flow path. Also, the first chamber 14 is disposed between the second chamber 16 and the purge port 20 along the fluid flow path. Furthermore, the second chamber 16 is in series with the first chamber 14 along the flow path such that, for example, in the charging mode, fluid first flows through the first chamber 14 and subsequently to the second chamber 16 along the fluid flow path. While the vent port 22 is shown schematically in Figure 2 as being directly downstream from the second chamber 16, it should be understood that the canister 12 may include other internal volume spaces such as other chamber(s) between the second chamber 16 and the vent port 22 along the fluid flow path.Atty Docket No.200451.216711-WO (PH24052)

[0039] Each of the first chamber 14 and second chamber 16 are defined at least in part by walls of the casing 12. Also, typically each chamber 14, 16 is defined in part by a partition 24, 26, respectively, in the form a screen, a perforated plate, or similar. As such, a void space 28 exists in the internal volume of the casing 12 between the first chamber 14 and the second chamber 16. The void space 28 is along the fluid flow path through the internal volume of the casing and spaces the second chamber 16 from the first chamber 14 along the fluid flow path. The first chamber 14 has a first volume defined by walls of the casing 12 and the partition 24, and the second chamber 16 has a second volume defined by walls of the casing 12 and the partition 26. The first chamber 14 is a main chamber, and as such the volume of the second chamber 16 is smaller than the volume of the first chamber 14. Particularly, the volume of the second chamber 16 is significantly smaller than the volume of the first chamber 14, and more specifically, in contrast to conventional evaporative emissions canisters, the ratio of the first volume of the first chamber 14 to the second volume of the second chamber 16 is in a range of approximately 85:15 to 90:10.

[0040] A first bed of adsorbent material 30 is disposed in the first chamber 14, and similarly a second bed of adsorbent material 32 is disposed in the second chamber 16. The second bed of adsorbent material 32 is in direct series with the first bed of adsorbent material 30 along the fluid flow path such that no other bed of adsorbent material is between the first bed of adsorbent material and the second bed of adsorbent material along the fluid flow path. The adsorbent materials 30, 32 forming the beds preferably may be a bulk activated material that is an activated carbon such as a granular carbon, a pellet carbon, or a powder carbon. The adsorbent materials, however, may be other types or forms of adsorbent material such as spherical, honeycomb, cylindrical, structured media of an extruded, wound, folded, pleated, corrugated, bonded, or poured form. The partitions 24, 26 are typically urged against the beds of adsorbent materials 30, 32, respectively, by resilient members such as coil springs or similar. The partitions 24, 26 thereby pack and hold the adsorbent materials 30, 32 in the chambers 14, 16, and as such the volume of the first bed of adsorbent material 30 is equivalent to the volume of the first chamber 14, and likewise the volume of the second bed of adsorbent material 32 is equivalent to the volume of the second chamber 16. Further, it should be understood that by “volume” of adsorbent material, the volume includes void spaces between individual particles or pieces (e.g., pellets) of adsorbent material forming the bed and / or void spaces within the individual particles or pieces of adsorbent material and thus the volume is the total volumetric space occupied by the bed of adsorbent material. As such, the “volume” is not a nominal volume that does not take into account void spaces within and between the adsorbent particles or within the adsorbent particles themselves. In contrast to conventional canisters, in embodiments of the canister 10 the first bed of adsorbent material 30 makes up approximately 85% to 90% of the total volume of adsorbent materialAtty Docket No.200451.216711-WO (PH24052) contained within the internal volume of the casing 12. Further, second bed of adsorbent material 32 makes up 10% to 15% of a total volume of adsorbent material contained within the internal volume of the canister.

[0041] Conventional canisters such as shown in Figure 1 keep the volume of adsorbent in the first chamber below 80% of the total volume of adsorbent, and typically keep the volume to a maximum of 60% to 70% of the total volume of adsorbent. This is due to the high flow restriction that is typically created by a high volume greater than 70% in the first chamber, which can lead to undesirable effects such as affecting tank refueling operations. In order to avoid high flow restriction, in further contrast to conventional canisters, the embodiments of the canister 10 have a chamber (and hence adsorbent bed) geometry in which a ratio (L / D) of the length L of the chamber to a diameter D of the chamber is at or below a value of 1 for each chamber of the canister 10. Particularly, in contrast to conventional canisters in which the L / D of the second chamber is generally between 3 and 5, as shown in Figure 2 the ratio (L2 / D2) of length to diameter of the second chamber 16 of the canister 10 is less than or equal to 1. It should be understood that the “length” of the chamber may correspond to the height of the chamber and may be the distance along the fluid flow direction. It should also be understood that the “diameter” of the chamber generally corresponds to a width of the chamber in a direction perpendicular to the length direction (i.e. a cross-section of the chamber), but if the cross-section of the chamber is not circular and is, for example, a generally square or rectangular shape, the “diameter” is a distance across the cross- sectional shape through the center and may correspond to the length of the side of the cross- sectional shape.

[0042] With reference to Figure 3, when the geometry of the canister 10 is made such that the value of L2 / D2 of the second chamber 16 is less than or equal to 1 (specifically the value of L2 / D2 is set to 1 in the graph), the flow restriction through the canister 10 is kept low in a range of generally 200 to 300 Pa when the volume of adsorbent in the first chamber 14 is between 85% and 90% of the total adsorbent volume. Also, the gross bleed from the canister 10 is also kept low at generally 200 mg when the volume of adsorbent in the first chamber 14 is between 85% and 90% of the total adsorbent volume. Furthermore, with reference to Figure 4, when the value of L2 / D2 of the second chamber 16 is set at 1 or less, the flow restriction is significantly lower than conventional canisters in which the L2 / D2of the second chamber is set at 3 or greater. Also, when the value of L2 / D2of the second chamber 16 is set at 1 or less, the adsorbent volume in the first chamber 14 can be made significantly larger (approximately 90% of the volume) before the flow restriction begins to increase, in contrast to conventional canisters having an L2 / D2 of greater than 3 in which the flow restriction begins to increase significantly when the volume of adsorbent in the first chamber is greater thanAtty Docket No.200451.216711-WO (PH24052)

[0043] Advantageously, due to the reduction in gross bleed through the canister 10, the canister 10 reduces the need or required size of a downstream vapor scrubber such as a monolith / honeycomb, thereby reducing cost. Further, due to the reduction of flow restriction in the canister 10, the canister can support alternative scrubber materials such as a carbon sheet, graphene, or a small quantity of activated carbon. The canister 10 may also maximize the use of less costly adsorbents in the form of granular or powdered bulk activated carbon. Additionally, the canister 10 may allow for the addition of dust filters.

[0044] It is to be understood that the appended claims are not limited to express and particular compounds, compositions, or methods described in the detailed description, which may vary between particular embodiments which fall within the scope of the appended claims. With respect to any Markush groups relied upon herein for describing particular features or aspects of various embodiments, different, special, and / or unexpected results may be obtained from each member of the respective Markush group independent from all other Markush members. Each member of a Markush group may be relied upon individually and or in combination and provides adequate support for specific embodiments within the scope of the appended claims.

[0045] Further, any ranges and subranges relied upon in describing various embodiments of the present invention independently and collectively fall within the scope of the appended claims, and are understood to describe and contemplate all ranges including whole and / or fractional values therein, even if such values are not expressly written herein. One of skill in the art readily recognizes that the enumerated ranges and subranges sufficiently describe and enable various embodiments of the present invention, and such ranges and subranges may be further delineated into relevant halves, thirds, quarters, fifths, and so on. As just one example, a range “of from 0.1 to 0.9” may be further delineated into a lower third, i.e., from 0.1 to 0.3, a middle third, i.e., from 0.4 to 0.6, and an upper third, i.e., from 0.7 to 0.9, which individually and collectively are within the scope of the appended claims, and may be relied upon individually and / or collectively and provide adequate support for specific embodiments within the scope of the appended claims. In addition, with respect to the language which defines or modifies a range, such as “at least,” “greater than,” “less than,” “no more than,” and the like, it is to be understood that such language includes subranges and / or an upper or lower limit. As another example, a range of “at least 10” inherently includes a subrange of from at least 10 to 35, a subrange of from at least 10 to 25, a subrange of from 25 to 35, and so on, and each subrange may be relied upon individually and / or collectively and provides adequate support for specific embodiments within the scope of the appended claims. Finally, an individual number within a disclosed range may be relied upon and provides adequate support for specific embodiments within the scope of the appended claims. For example, a range “of from 1 to 9” includes various individual integers, such as 3, as well as individualAtty Docket No.200451.216711-WO (PH24052) numbers including a decimal point (or fraction), such as 4.1, which may be relied upon and provide adequate support for specific embodiments within the scope of the appended claims.

[0046] The above description is that of current embodiments of the invention. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. This disclosure is presented for illustrative purposes and should not be interpreted as an exhaustive description of all embodiments of the invention or to limit the scope of the claims to the specific elements illustrated or described in connection with these embodiments. For example, and without limitation, any individual element(s) of the described invention may be replaced by alternative elements that provide substantially similar functionality or otherwise provide adequate operation. This includes, for example, presently known alternative elements, such as those that might be currently known to one skilled in the art, and alternative elements that may be developed in the future, such as those that one skilled in the art might, upon development, recognize as an alternative. Further, the disclosed embodiments include a plurality of features that are described in concert and that might cooperatively provide a collection of benefits. The present invention is not limited to only those embodiments that include all of these features or that provide all of the stated benefits, except to the extent otherwise expressly set forth in the issued claims. Any reference to claim elements by ordinal terms, for example “first,” “second,” and “third,” are used for clarity, and are not to be construed as limiting the order in which the claim elements appear. Any reference to claim elements in the singular, for example, using the articles “a,” “an,” “the” or “said,” is not to be construed as limiting the element to the singular.

Claims

Atty Docket No.200451.216711-WO (PH24052) CLAIMS What is claimed is:

1. An evaporative emissions canister (10) comprising: a casing (12) defining an internal volume therein; the casing including a charge port (18) and a vent port (22) in fluid communication with the internal volume; the internal volume being partitioned into a plurality of chambers including a first chamber (14) and a separate second chamber (16), the first chamber being adjacent to the charge port; the first chamber having a first volume, and the second chamber having a second volume that is smaller than the first volume; a first bed of adsorbent material (30) disposed in the first chamber; and a second bed of adsorbent material (32) disposed in the second chamber; wherein a ratio of the first volume of the first chamber to the second volume of the second chamber is in a range of 85:15 to 90:

10.

2. The evaporative emissions canister (10) of claim 1, wherein: the first bed of adsorbent material (30) constitutes 85% to 90% of a total volume of adsorbent material contained within the internal volume of the canister (10); and the second bed of adsorbent material (32) constitutes 10% to 15% of a total volume of adsorbent material contained within the internal volume of the canister (10).

3. The evaporative emissions canister (10) of claim 1 or 2, wherein a ratio (L / D) of a length of the second chamber (16) to a diameter of the second chamber (16) is less than or equal to 1.

4. The evaporative emissions canister (10) of any one of the preceding claims, wherein: i) the second chamber (16) is in series with the first chamber (14); ii) the second chamber (16) is farther from the charge port (18) than the first chamber (14); the second chamber (16) is closer to the vent port (22) than the first chamber (14); iv) the second chamber (16) is downstream from the first chamber (14) in a charging flow direction through the internal volume of the canister (10); or v) any combination of i) through iv).

5. The evaporative emissions canister (10) of any one of the preceding claims, wherein the second bed of adsorbent material (32) is a last volume of adsorbent material in a charging flow direction.Atty Docket No.200451.216711-WO (PH24052) 6. The evaporative emissions canister (10) of any one of the preceding claims, wherein the second chamber (16) is spaced from the first chamber (14).

7. The evaporative emissions canister (10) of any one of the preceding claims, further comprising a purge port (20), wherein the first chamber (14) is adjacent the purge port.

8. A fuel vapor canister (10) for adsorbing fuel evaporated in a fuel tank (40) of a vehicle (44), the fuel vapor canister comprising: a casing (12) defining an internal volume therein; the casing including a tank port (18) for receiving fuel vapor from the fuel tank (40) into the internal volume; the casing including a purge port (20) for delivering fuel vapor from the internal volume to an engine (42) of the vehicle (44); the casing including a vent port (22) for communicating the internal volume with ambient air; the tank port, the purge port, and the vent port being in fluid communication with the internal volume; the internal volume being partitioned into a plurality of chambers including a first chamber (14) and a separate second chamber (16), the first chamber being adjacent to the tank port; the first chamber having a first volume, and the second chamber having a second volume that is smaller than the first volume; a first bed of adsorbent material (30) disposed in the first chamber; and a second bed of adsorbent material (32) disposed in the second chamber; wherein a ratio of the first volume of the first chamber to the second volume of the second chamber is in a range of 85:15 to 90:

10.

9. The fuel vapor canister (10) of claim 8, wherein: the first bed of adsorbent material (30) constitutes 85% to 90% of a total volume of adsorbent material contained within the internal volume of the canister (10); and the second bed of adsorbent material (32) constitutes 10% to 15% of a total volume of adsorbent material contained within the internal volume of the canister (10).

10. The fuel vapor canister (10) of claim 8 or 9, wherein a ratio (L / D) of a length of the second chamber (16) to a diameter of the second chamber (16) is less than or equal to 1.Atty Docket No.200451.216711-WO (PH24052) 11. The fuel vapor canister (10) of any one of claims 8 to 10, wherein a fluid flow path extends through the internal volume of the canister, the fluid flow path extending from the tank port (18) to the vent port (22) in a charging flow direction.

12. The fuel vapor canister (10) of claim 11, wherein: i) the second chamber (16) is downstream from first chamber (14) along the fluid flow path in the charging flow direction; ii) the second chamber (16) is spaced from the first chamber (14) along the fluid flow path; iii) the second bed of adsorbent material (32) is in direct series with the first bed of adsorbent material (30) along the fluid flow path such that no other bed of adsorbent material is between the first bed of adsorbent material and the second bed of adsorbent material along the fluid flow path; or iv) any combination of i) through iii).

13. A method of making an evaporative emissions canister (10), the method comprising the steps of: forming a casing (12) defining an internal volume therein, the casing including a charge port (18) and a vent port (22) in fluid communication with the internal volume, wherein the internal volume is partitioned into a plurality of chambers including a first chamber (14) and a separate second chamber (16), the first chamber being adjacent to the charge port, the first chamber having a first volume, the second chamber having a second volume that is smaller than the first volume, and a ratio of the first volume of the first chamber to the second volume of the second chamber is in a range of 85:15 to 90:10; disposing a first bed of adsorbent material (30) in the first chamber; and disposing a second bed of adsorbent material (32) in the second chamber.

14. The method of claim 13, wherein: the first bed of adsorbent material (30) constitutes 85% to 90% of a total volume of adsorbent material contained within the internal volume of the canister (10); and the second bed of adsorbent material (32) constitutes 10% to 15% of a total volume of adsorbent material contained within the internal volume of the canister (10).

15. The method of claim 13 or 14, wherein a ratio (L / D) of a length of the second chamber (16) to a diameter of the second chamber (16) is less than or equal to 1.

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