(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2002/0073847 A1
`Sheline et al.
`(43) Pub. Date:
`Jun. 20, 2002
`
`US 20020073847A1
`
`(54) CELL WITHINA CELL MONOLITH
`STRUCTURE FOR AN EVAPORATIVE
`EMISSIONS HYDROCARBON SCRUBBER
`
`(21) Appl. No.:
`
`09/738,558
`
`(22) Filed:
`
`Dec. 15, 2000
`
`(76) Inventors: Matthew R. Sheline, Grand Blanc, MI
`(US); Charles H. Covert, Manchester,
`NY (US); Susan LaBine, Avon, NY
`(US); Jonathan M. Oemoke,
`Rochester, NY (US); Eileen A.
`Scardino, Rochester, NY (US)
`
`Correspondence Address:
`Vincent A. CichoSZ
`DELPHITECHNOLOGIES, INC.
`1450 West Long Lake
`Troy, MI 48007 (US)
`
`
`
`Publication Classification
`
`(51) Int. Cl." ..................................................... B01D 53/02
`(52) U.S. Cl. ................................................. 95/143; 96/108
`(57)
`ABSTRACT
`A monolith for use in an evaporative emissions hydrocarbon
`scrubber is disclosed. The monolith, which is concentrically
`disposed with a shell, has at least one cell group disposed
`around at least two individual cells, Such that the cell group
`comprises at least three thick walls. The individual cells
`comprise at least on thin wall, with the thick walls being
`thicker than the thin wall. A method for using the evapora
`tive emissions hydrocarbon Scrubber is also disclosed.
`
`26
`
`22
`
`24
`
` MAHLE-1022
`U.S. Patent No. RE38,844
`
`

`

`Patent Application Publication Jun. 20, 2002
`
`Patent Application Publication
`
`Jun. 20, 2002
`
`US 2002/0073847 A1
`
`US 2002/0073847 A1
`
`FIG. 1
`FIG. 1
`Prior Art
`Prior Art
`
`
`
`N
`
`26
`
`26
`
`22
`
`24
`24
`
`
`
`1.
`
`28
`
`
`
`
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`
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`Sk1-1
`
`7Y30
`
`

`

`US 2002/0073847 A1
`US 2002/0073847 A1
`
`Jun. 20, 2002
`Jun. 20, 2002
`
`CELL WITHIN A CELL MONOLITH STRUCTURE
`CELL WITHINA CELL MONOLTH STRUCTURE
`FOR AN EVAPORATIVE EMISSIONS
`FOR AN EVAPORATIVE EMISSIONS
`HYDROCARBON SCRUBBER
`HYDROCARBON SCRUBBER
`
`TECHNICAL FIELD
`TECHNICAL FIELD
`0001. The disclosure relates to the evaporative emissions
`[0001] The disclosure relates to the evaporative emissions
`from a gasoline tank in motor vehicles and, more particu
`from a gasoline tank in motor vehicles and, more particu-
`larly, to the Scrubber used in filtering the evaporative emis
`larly, to the scrubber used in filtering the evaporative emis-
`sions.
`Sions.
`
`BACKGROUND
`BACKGROUND
`0002 Motor vehicles emit hydrocarbons as a result of the
`[0002] Motor vehicles emit hydrocarbons as a result of the
`evaporation of fuel. Generally, Such evaporative emissions
`evaporation of fuel. Generally, such evaporative emissions
`result from the venting of fuel vapors from the fuel tank due
`result from the venting of fuel vapors from the fuel tank due
`to diurnal changes in ambient pressure and/or temperature,
`to diurnal changes in ambient pressure and/or temperature,
`the vaporization of fuel by a hot engine and/or exhaust
`the vaporization of fuel by a hot engine and/or exhaust
`System, and the escape of fuel vapors during refueling of the
`system, and the escape of fuel vapors during refueling of the
`vehicle. The venting of fuel vapor from the fuel tank due to
`vehicle. The venting of fuel vapor from the fuel tank due to
`diurnal pressure and/or temperature changes (i.e., diurnal
`diurnal pressure and/or temperature changes (i.e., diurnal
`emissions) is responsible for a majority of evaporative
`emissions) is responsible for a majority of evaporative
`emissions. Diurnal changes in pressure and/or temperature
`emissions. Diurnal changes in pressure and/or temperature
`cause air to flow into and out of the fuel tank. Air flowing
`cause air to flow into and out of the fuel tank. Air flowing
`out of the fuel tank inevitably carries fuel vapor, which is
`out of the fuel tank inevitably carries fuel vapor, which is
`created by the evaporation of fuel into the air contained
`created by the evaporation of fuel into the air contained
`above the fuel within the fuel tank. If this flow of air is left
`above the fuel within the fuel tank. If this flow of air is left
`untreated and is allowed to escape directly into the atmo
`untreated and is allowed to escape directly into the atmo-
`Sphere, undesirable emissions occur.
`sphere, undesirable emissions occur.
`0.003 Motor vehicle manufacturers have reduced the
`[0003] Motor vehicle manufacturers have reduced the
`level of diurnal emissions through the use of evaporative
`level of diurnal emissions through the use of evaporative
`canisters such as the evaporative canister structure and
`canisterS Such as the evaporative canister Structure and
`operation set forth in US. Pat. No. 5,910,637, the disclosure
`operation set forth in U.S. Pat. No. 5,910,637, the disclosure
`of which is incorporated herein by reference. Generally, an
`of which is incorporated herein by reference. Generally, an
`evaporative canister has a vapor inlet, a purge port and a vent
`evaporative canister has a vapor inlet, a purge port and a vent
`port. The vapor inlet is fluidly connected by a vapor conduit
`port. The vapor inlet is fluidly connected by a vapor conduit
`to the air Space in the fuel tank. Diurnal changes in pressure
`to the air space in the fuel tank. Diurnal changes in pressure
`and/or temperature causes air within the fuel tank to flow
`and/or temperature causes air within the fuel tank to flow
`through the vapor conduit and into the evaporative canister
`through the vapor conduit and into the evaporative canister
`via the vapor inlet. The air carries fuel vapor and/or hydro
`via the vapor inlet. The air carries fuel vapor and/or hydro-
`carbons. The evaporative canister contains a sorbent mate-
`carbons. The evaporative canister contains a Sorbent mate
`rial, such as an activated carbon, that strips fuel vapor from
`rial, Such as an activated carbon, that Strips fuel vapor from
`the air as it flows through the canister. The treated air then
`the air as it flows through the canister. The treated air then
`flows out the vent port and into the atmosphere. The purge
`flows out the vent port and into the atmosphere. The purge
`port is fluidly connected by a valved purge conduit to the
`port is fluidly connected by a valved purge conduit to the
`combustion air intake of the motor vehicle engine. When the
`combustion air intake of the motor vehicle engine. When the
`engine is running, the combustion air intake is at Sub
`engine is running,
`the combustion air intake is at sub-
`atmospheric pressure, and the valve is opened to thereby
`atmospheric pressure, and the valve is opened to thereby
`connect the purge port to the combustion air intake. Fresh air
`connect the purge port to the combustion air intake. Fresh air
`is drawn by the Sub-atmospheric pressure through the vent
`is drawn by the sub-atmospheric pressure through the vent
`port and into the evaporative canister. The fresh air flows
`port and into the evaporative canister. The fresh air flows
`through the Sorbent material, out the purge port and into the
`through the sorbent material, out the purge port and into the
`combustion air inlet. The flow of fresh air through the
`combustion air inlet. The flow of fresh air through the
`evaporative canister Strips the Sorbent material of Stored fuel
`evaporative canister strips the sorbent material of stored fuel
`Vapor and/or hydrocarbons, thereby purging the evaporative
`vapor and/or hydrocarbons, thereby purging the evaporative
`canister of hydrocarbons.
`canister of hydrocarbons.
`0004. Due to incomplete desorption of the hydrocarbons,
`[0004] Due to incomplete desorption of the hydrocarbons,
`minute levels of hydrocarbons remain stored in the sorbent
`minute levels of hydrocarbons remain stored in the sorbent
`material of a purged evaporative canister. Bleed emissions
`material of a purged evaporative canister. Bleed emissions
`are believed to result from the release of these stored
`are believed to result from the release of these stored
`hydrocarbons (i.e., the hydrocarbon heel) from the evapo
`hydrocarbons (i.e., the hydrocarbon heel) from the evapo-
`rative canister into the atmosphere. Bleed emissions typi
`rative canister into the atmosphere. Bleed emissions typi-
`cally occur, for example, during the heating of the fuel tank
`cally occur, for example, during the heating of the fuel tank
`during a diurnal cycle. The heating of the fuel tank causes air
`during a diurnal cycle. The heating of the fuel tank causes air
`
`to flow from the fuel tank, through the canister, out the vent
`to flow from the fuel tank, through the canister, out the vent
`port and into the atmosphere. The air carries the hydrocar
`port and into the atmosphere. The air carries the hydrocar-
`bon heel out of the canister and into the atmosphere, thereby
`bon heel out of the canister and into the atmosphere, thereby
`resulting in the release of bleed emissions.
`resulting in the release of bleed emissions.
`0005. In order to reduce bleed emissions some motor
`[0005]
`In order to reduce bleed emissions some motor
`vehicles employ an auxiliary canister. The auxiliary canister
`vehicles employ an auxiliary canister. The auxiliary canister
`is placed in series with and further filters the treated air
`is placed in series with and further filters the treated air
`flowing out the vent port of the main evaporative canister.
`flowing out the vent port of the main evaporative canister.
`The auxiliary canister typically uses the same Sorbent mate
`The auxiliary canister typically uses the same sorbent mate-
`rial (i.e., granular or pelletized carbon) as is used in the main
`rial (i.e., granular or pelletized carbon) as is used in the main
`evaporative canister to thereby increase the hydrocarbon
`evaporative canister to thereby increase the hydrocarbon
`capacity of the evaporative emission control System. How
`capacity of the evaporative emission control system. How-
`ever, in order to achieve Sufficient hydrocarbon capacity,
`ever, in order to achieve sufficient hydrocarbon capacity,
`auxiliary canisters are generally highly restrictive to the flow
`auxiliary canisters are generally highly restrictive to the flow
`of air. Thus, the auxiliary canister must be bypassed in order
`of air. Thus, the auxiliary canister must be bypassed in order
`to be compatible with vehicle refueling vapor recovery
`to be compatible with vehicle refueling vapor recovery
`Systems. Bypassing an auxiliary canister requires the addi
`systems. Bypassing an auxiliary canister requires the addi-
`tion of valves and conduits to the evaporative emissions
`tion of valves and conduits to the evaporative emissions
`control System, and thus adds cost and complexity to the
`control system, and thus adds cost and complexity to the
`system. Furthermore, the restrictive airflow characteristic of
`system. Furthermore, the restrictive airflow characteristic of
`the auxiliary canister makes purging the Volume of Sorbent
`the auxiliary canister makes purging the volume of sorbent
`material inefficient, especially in Small displacement
`material
`inefficient,
`especially in small displacement
`engines. Moreover, vehicles which incorporate a more effi
`engines. Moreover, vehicles which incorporate a more effi-
`cient evaporative canister and/or an auxiliary canister typi
`cient evaporative canister and/or an auxiliary canister typi-
`cally do not reduce bleed emissions to a level required to
`cally do not reduce bleed emissions to a level required to
`classify the vehicle as a Super Ultra Low Emissions Vehicle
`classify the vehicle as a Super Ultra Low Emissions Vehicle
`(SULEV) or as a Practically Zero Emissions Vehicle
`(SULEV) or as a Practically Zero Emissions Vehicle
`(PZEV).
`(PZEV).
`0006 AS illustrated in FIG. 1, a prior art cell monolith
`[0006] As illustrated in FIG. 1, a prior art cell monolith
`10, e.g., as disclosed in US. Pat. No. 5,914,294 to Park et
`10, e.g., as disclosed in U.S. Pat. No. 5,914.294 to Park et
`al., has a plurality of passages 12 extending through the
`al., has a plurality of passages 12 extending through the
`monolith 10 from a frontal end 14 to a rearward end 16. The
`monolith 10 from a frontal end 14 to a rearward end 16. The
`passages 12 are formed by Surrounding walls 18. The
`passages 12 are formed by surrounding walls 18. The
`passages are encased by an Outer Skin 20. While this design
`passages are encased by an outer skin 20. While this design
`is adequate for its intended purpose, there is a continued
`is adequate for its intended purpose, there is a continued
`need for structurally sound monolith, which reduces bleed
`need for structurally sound monolith, which reduces bleed
`emissions and should have a low flow restriction, thereby
`emissions and should have a low flow restriction, thereby
`increasing purge efficiency.
`increasing purge efficiency.
`SUMMARY
`SUMMARY
`0007. The drawbacks and disadvantages of the prior art
`[0007] The drawbacks and disadvantages of the prior art
`are overcome by the exemplary embodiments of a cell
`are overcome by the exemplary embodiments of a cell
`within a cell monolith structure for an evaporative emissions
`within a cell monolith Structure for an evaporative emissions
`hydrocarbon Scrubber. A monolith for use in an evaporative
`hydrocarbon scrubber. A monolith for use in an evaporative
`emissions hydrocarbon Scrubber is disclosed. A shell is
`emissions hydrocarbon scrubber is disclosed. A shell
`is
`concentrically disposed around a monolith. The monolith
`concentrically disposed around a monolith. The monolith
`has at least one cell group disposed around at least two
`has at least one cell group disposed around at least two
`individual cells, Such that the cell group comprises at least
`individual cells, such that the cell group comprises at least
`three thick walls. The individual cells comprise at least one
`three thick walls. The individual cells comprise at least one
`thin wall, with the thick walls being thicker than the thin
`thin wall, with the thick walls being thicker than the thin
`wall.
`wall.
`0008. The method for using the evaporative emissions
`[0008] The method for using the evaporative emissions
`hydrocarbon scrubber is also disclosed. The method com-
`hydrocarbon scrubber is also disclosed. The method com
`prises introducing a gas to a first end of a monolith com
`prises introducing a gas to a first end of a monolith com-
`prising carbon. The monolith, which is concentrically dis
`prising carbon. The monolith, which is concentrically dis-
`posed within a shell, has at least one cell group disposed
`posed within a shell, has at least one cell group disposed
`around at least two individual cells. The cell group com-
`around at least two individual cells. The cell group com
`prises at least three thick walls, and the individual cells
`prises at least three thick walls, and the individual cells
`comprises at least one thin wall. The thick wall is thicker
`comprises at least one thin wall. The thick wall is thicker
`than the thin wall. Hydrocarbons are removed from the gas
`than the thin wall. Hydrocarbons are removed from the gas
`with the monolith prior to exhausting the gas through a
`with the monolith prior to exhausting the gas through a
`second end of the monolith. The hydrocarbons can be
`second end of the monolith. The hydrocarbons can be
`
`

`

`US 2002/0073847 A1
`US 2002/0073847 A1
`
`Jun. 20, 2002
`Jun. 20, 2002
`
`removed from the monolith by passing air from the Second
`removed from the monolith by passing air from the second
`end through the monolith and out the first end.
`end through the monolith and out the first end.
`BRIEF DESCRIPTION OF THE DRAWINGS
`BRIEF DESCRIPTION OF THE DRAWINGS
`0009 Referring now to the figure, which is meant to be
`[0009] Referring now to the figure, which is meant to be
`exemplary, not limiting.
`exemplary, not limiting.
`0.010
`FIG. 1 is a perspective view of a prior art cell
`[0010] FIG. 1 is a perspective view of a prior art cell
`monolith structure.
`monolith Structure.
`0.011
`FIG. 2 is a cross-sectional view of the cell within
`[0011] FIG. 2 is a cross-sectional view of the cell within
`a cell monolith structure.
`a cell monolith Structure.
`
`DETAILED DESCRIPTION OF THE
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`PREFERRED EMBODIMENTS
`0012. When evaporative emissions are released from the
`[0012] When evaporative emissions are released from the
`fuel tank due to diurnal pressure and/or temperature
`fuel
`tank due to diurnal pressure and/or
`temperature
`changes, the emissions can be captured in an evaporative
`changes, the emissions can be captured in an evaporative
`canister. The monolith can be employed in the main evapo
`canister. The monolith can be employed in the main evapo-
`rative canister, an auxiliary canister, or a combination
`rative canister, an auxiliary canister, or a combination
`thereof. While different designs of monoliths exist, includ
`thereof. While different designs of monoliths exist, includ-
`ing circular or rectangular designs, reference to a particular
`ing circular or rectangular designs, reference to a particular
`monolith design is intended to also represent Similar com
`monolith design is intended to also represent similar com-
`ponents in other monolith designs, where applicable. Addi
`ponents in other monolith designs, where applicable. Addi-
`tionally, this monolith design can be employed as a Single
`tionally, this monolith design can be employed as a single
`and only canister, or in conjunction with additional canisters.
`and only canister, or in conjunction with additional canisters.
`0013 FIG. 1 illustrates a cross-sectional view of the cell
`[0013] FIG. 1 illustrates a cross-sectional view of the cell
`within a cell monolith structure 20 for an evaporative
`within a cell monolith structure 20 for an evaporative
`emissions hydrocarbon scrubber. The monolith 20 com
`emissions hydrocarbon scrubber. The monolith 20 com-
`prises a combination of thin walls 24 and thick walls 22.
`prises a combination of thin walls 24 and thick walls 22.
`These walls, which preferably run the length of the monolith
`These walls, which preferably run the length of the monolith
`20, can be disposed perpendicular to the axis of the mono
`20, can be disposed perpendicular to the axis of the mono-
`lith. Typically, the walls 22, 24 are disposed horizontal and
`lith. Typically, the walls 22, 24 are disposed horizontal and
`Vertical, at an angle perpendicular to the axis. The thicker
`vertical, at an angle perpendicular to the axis. The thicker
`walls 22 define cell groups 26 comprising Several cells 28
`walls 22 define cell groups 26 comprising several cells 28
`defined by the thin walls 24. Depending upon the specific
`defined by the thin walls 24. Depending upon the specific
`size and geometry of the monolith, the number of connected
`Size and geometry of the monolith, the number of connected
`main cell groups 26 can vary. The quantity of thin and thick
`main cell groups 26 can vary. The quantity of thin and thick
`walls is a balance between the desired structural integrity
`walls is a balance between the desired Structural integrity
`and the surface area desired to adsorb a sufficient amount of
`and the Surface area desired to adsorb a Sufficient amount of
`hydrocarbons in the fuel vapors. Generally, there are more
`hydrocarbons in the fuel vapors. Generally, there are more
`thinner walls 24 disposed within the monolith 20 than
`thinner walls 24 disposed within the monolith 20 than
`thicker walls 22.
`thicker walls 22.
`0.014. The geometry of the cells, both those defined by
`[0014] The geometry of the cells, both those defined by
`thick walls 22 and those defined by thin walls 24, is also
`thick walls 22 and those defined by thin walls 24, is also
`based upon the desired Structural integrity, Surface area, and
`based upon the desired structural integrity, surface area, and
`optionally upon ease of manufacture. Possible designs range
`optionally upon ease of manufacture. Possible designs range
`from rounded to multi-sided figures, e.g., Square, rectangle,
`from rounded to multi-sided figures, e.g., square, rectangle,
`oblong, circular, triangular, hexagonal, octagonal, and the
`oblong, circular, triangular, hexagonal, octagonal, and the
`like, as well as combinations comprising at least one of the
`like, as well as combinations comprising at least one of the
`foregoing geometries defining either the individual cells 28
`foregoing geometries defining either the individual cells 28
`and/or the main cell groups 26. For example, the interlaced
`and/or the main cell groups 26. For example, the interlaced
`thick and thin walls 22, 24 can perpendicularly intersect
`thick and thin walls 22, 24 can perpendicularly intersect
`creating a Square design as illustrated by individual cell 28,
`creating a square design as illustrated by individual cell 28,
`with the exception of when the interlaced thick and thin
`with the exception of when the interlaced thick and thin
`walls 22, 24 intersect with the outer wall 30. Additionally,
`walls 22, 24 intersect with the outer wall 30. Additionally,
`the thin walls 24 can form different shaped cells than the cell
`the thin walls 24 can form different shaped cells than the cell
`groupS 26. For example, the cell group 26 may comprise a
`groups 26. For example, the cell group 26 may comprise a
`rectangular geometry while the cells 28 within the cell group
`rectangular geometry while the cells 28 within the cell group
`26 may comprise a Square geometry.
`26 may comprise a square geometry.
`[0015] The location and orientation of the thick and thin
`0.015 The location and orientation of the thick and thin
`walls 22, 24 can be dependent upon the overall shape of the
`walls 22, 24 can be dependent upon the overall shape of the
`monolith 20, Such as, e.g., circular, oval, rectangular, trap
`monolith 20, such as, e.g., circular, oval, rectangular, trap-
`
`eZoidal, non-circular, and other Similar geometric configu
`ezoidal, non-circular, and other similar geometric configu-
`rations, and the like. The cell shape and size is based upon
`rations, and the like. The cell shape and size is based upon
`the overall cell density. The number of cells within the
`the overall cell density. The number of cells within the
`monolith can be about 200 to about 600 individual cells,
`monolith can be about 200 to about 600 individual cells,
`with about 200 to about 400 individual cells preferred. The
`with about 200 to about 400 individual cells preferred. The
`number of individual cells within each cell group can vary,
`number of individual cells within each cell group can vary,
`with at least four individual cells per cell group preferred,
`with at least four individual cells per cell group preferred,
`and at least nine individual cells per cell group especially
`and at least nine individual cells per cell group especially
`preferred.
`preferred.
`0016. The thickness of the thick and thin walls 22, 24 is
`[0016] The thickness of the thick and thin walls 22, 24 is
`typically dependent upon the desired overall Structural integ
`typically dependent upon the desired overall structural integ-
`rity of the monolith 20. The thickness is preferably sufficient
`rity of the monolith 20. The thickness is preferably sufficient
`to impart the desired overall Structural integrity, without
`to impart the desired overall structural integrity, without
`inhibiting the passage of evaporative emissions. Preferably,
`inhibiting the passage of evaporative emissions. Preferably,
`the thickness of the thicker walls 22 can be about 0.008
`the thickness of the thicker walls 22 can be about 0.008
`inches (in.) or greater, with about 0.008 in. to about 0.020 in.
`inches (in.) or greater, with about 0.008 in. to about 0.020 in.
`preferred, and about 0.010 in. to about 0.012 in. especially
`preferred, and about 0.010 in. to about 0.012 in. especially
`preferred. The thickness of the thinner walls 24 can be less
`preferred. The thickness of the thinner walls 24 can be less
`than about 0.008 in., with about 0.001 in. to about 0.008 in.
`than about 0.008 in., with about 0.001 in. to about 0.008 in.
`preferred, and about 0.003 in. to about 0.004 in. especially
`preferred, and about 0.003 in. to about 0.004 in. especially
`preferred.
`preferred.
`0017. The monolith 20 can be comprised of a sorbent that
`[0017] The monolith 20 can be comprised of a sorbent that
`removes hydrocarbons from an air/vapor flow, including, but
`removes hydrocarbons from an air/vapor flow, including, but
`not limited to, activated carbon, and the like. This sorbent
`not limited to, activated carbon, and the like. This sorbent
`can be mixed with a binder to allow for the formation into
`can be mixed with a binder to allow for the formation into
`the desired shape. The various amounts of Sorbent and
`the desired shape. The various amounts of sorbent and
`binder can readily be determined by an artisan based upon
`binder can readily be determined by an artisan based upon
`the desired Structural integrity of the monolith and the
`the desired structural
`integrity of the monolith and the
`monolith production method. One example of a monolith
`monolith production method. One example of a monolith
`production process is disclosed in U.S. Pat. No. 5,914,294 to
`production process is disclosed in US. Pat. No. 5,914,294 to
`Park et al., which is hereby incorporated by reference.
`Park et al., which is hereby incorporated by reference.
`[0018] Once formed into the cell within a cell structure,
`0018. Once formed into the cell within a cell structure,
`the monolith is concentrically disposed within a Shell or
`the monolith is concentrically disposed within a shell or
`housing (i.e., a canister), and disposed in fluid communica
`housing (i.e., a canister), and disposed in fluid communica-
`tion with the fuel tank and the atmosphere external to the
`tion with the fuel tank and the atmosphere external to the
`motor vehicle. During operation, fuel vapor and air flow into
`motor vehicle. During operation, fuel vapor and air flow into
`a first end of the canister, and through the monolith, where
`a first end of the canister, and through the monolith, where
`the Sorbent Strips the hydrocarbons from the gas Stream,
`the sorbent strips the hydrocarbons from the gas stream,
`releasing the treated air to the atmosphere. The canister is
`releasing the treated air to the atmosphere. The canister is
`fluidly connected by a valved purge conduit to the combus
`fluidly connected by a valved purge conduit to the combus-
`tion air intake of the motor vehicle engine. When the engine
`tion air intake of the motor vehicle engine. When the engine
`is running, the combustion air intake is at Sub-atmospheric
`is running, the combustion air intake is at sub-atmospheric
`preSSure, and the valve is opened to thereby connect the
`pressure, and the valve is opened to thereby connect the
`purge port to the combustion air intake. Fresh air is drawn
`purge port to the combustion air intake. Fresh air is drawn
`by the Sub-atmospheric pressure through the vent port and
`by the sub-atmospheric pressure through the vent port and
`into the second end of the evaporative canister. The fresh air
`into the Second end of the evaporative canister. The fresh air
`flows through the monolith, Stripping the Sorbent of Stored
`flows through the monolith, stripping the sorbent of stored
`hydrocarbons.
`hydrocarbons.
`0019. The thinner walls 24 increases the desorption capa
`[0019] The thinner walls 24 increases the desorption capa-
`bility of the monolith 20, allowing for a more thorough
`bility of the monolith 20, allowing for a more thorough
`cleaning of the monolith of hydrocarbons. The performance
`cleaning of the monolith of hydrocarbons. The performance
`of the monolith 20 improves as the desorption capability is
`of the monolith 20 improves as the desorption capability is
`increased, since the ability to capture the fuel Vapor and/or
`increased, since the ability to capture the fuel vapor and/or
`hydrocarbons is more rapidly restored. The use of the thicker
`hydrocarbons is more rapidly restored. The use of the thicker
`walls 22, defining the main cell groups 26, increases the
`walls 22, defining the main cell groups 26, increases the
`structural integrity of the monolith 20 without compromis
`structural integrity of the monolith 20 without compromis-
`ing the open area for air flow. The plurality of the main cell
`ing the open area for air flow. The plurality of the main cell
`groupS 26 does not add any significant pressure differential
`groups 26 does not add any significant pressure differential
`across the monolith 20, when compared to a monolith with
`across the monolith 20, when compared to a monolith with
`uniform thicknesses, as illustrated in the prior art FIG. 1.
`uniform thicknesses, as illustrated in the prior art FIG. 1.
`0020 While preferred embodiments have been shown
`[0020] While preferred embodiments have been shown
`and described, various modifications and substitutions may
`and described, various modifications and Substitutions may
`
`

`

`US 2002/0073847 A1
`US 2002/0073847 A1
`
`Jun. 20, 2002
`Jun. 20, 2002
`
`be made thereto without departing from the Spirit and Scope
`be made thereto without departing from the spirit and scope
`of the invention. Accordingly, it is to be understood that the
`of the invention. Accordingly, it is to be understood that the
`apparatus and method have been described by way of
`apparatus and method have been described by way of
`illustration only, and such illustrations and embodiments as
`illustration only, and Such illustrations and embodiments as
`have been disclosed herein are not
`to be construed as
`have been disclosed herein are not to be construed as
`limiting to the claims.
`limiting to the claims.
`What is claimed is:
`What is claimed is:
`1. An evaporative emissions hydrocarbon Scrubber, com
`1. An evaporative emissions hydrocarbon scrubber, com-
`prising:
`prising:
`a monolith comprising carbon having at least one cell
`a monolith comprising carbon having at least one cell
`group disposed around at least two individual cells,
`group disposed around at least two individual cells,
`wherein Said cell group comprises at least three thick
`wherein said cell group comprises at least three thick
`walls, and Said individual cells comprising at least one
`walls, and said individual cells comprising at least one
`thin wall, said thick wall being thicker than said thin
`thin wall, said thick wall being thicker than said thin
`wall; and
`wall; and
`a shell concentrically disposed around Said monolith.
`a shell concentrically disposed around said monolith.
`2. The evaporative emissions hydrocarbon scrubber of
`2. The evaporative emissions hydrocarbon scrubber of
`claim 1, wherein Said thick walls are greater than about
`claim 1, wherein said thick walls are greater than about
`0.008 in. to about 0.020 in. in thickness.
`0.008 in. to about 0.020 in. in thickness.
`3. The evaporative emissions hydrocarbon scrubber of
`3. The evaporative emissions hydrocarbon scrubber of
`claim 2, wherein said thick walls are about 0.010 in. to about
`claim 2, wherein said thick walls are about 0.010 in. to about
`0.012 in. in thickness.
`0.012 in. in thickness.
`4. The evaporative emissions hydrocarbon scrubber of
`4. The evaporative emissions hydrocarbon scrubber of
`claim 1, wherein said thin walls are about 0.001 in. up to
`claim 1, wherein said thin walls are about 0.001 in. up to
`about 0.008 in. in thickness.
`about 0.008 in. in thickness.
`5. The evaporative emissions hydrocarbon scrubber of
`5. The evaporative emissions hydrocarbon scrubber of
`claim 4, wherein said thin walls are about 0.003 in. to about
`claim 4, wherein said thin walls are about 0.003 in. to about
`0.004 in. in thickness.
`0.004 in. in thickness.
`6. The evaporative emissions hydrocarbon scrubber of
`6. The evaporative emissions hydrocarbon scrubber of
`claim 1, wherein said monolith further comprises activated
`claim 1, wherein Said monolith further comprises activated
`carbon and a binder.
`carbon and a binder.
`
`7. The evaporative emissions hydrocarbon scrubber of
`7. The evaporative emissions hydrocarbon scrubber of
`claim 1, wherein at least four of said individual cells are
`claim 1, wherein at least four of Said individual cells are
`disposed within each of Said cell groups.
`disposed within each of said cell groups.
`8. The evaporative emissions hydrocarbon scrubber of
`8. The evaporative emissions hydrocarbon scrubber of
`claim 1, wherein at least nine of said individual cells are
`claim 1, wherein at least nine of Said individual cells are
`disposed within each of Said cell groups.
`disposed within each of said cell groups.
`9. The evaporative emissions hydrocarbon scrubber of
`9. The evaporative emissions hydrocarbon scrubber of
`claim 1, wherein said monolith comprises about 200 to about
`claim 1, wherein said monolith comprises about 200 to about
`600 of said individual cells.
`600 of said indiv