TECHNICAL FIELD

[0001] The present device and system relates to the storage and delivery of ammonia.

Particularly, the device relates to deep drawn, high compaction canister for storing a reductant, such as an ammonia adsorbing/desorbing material for use in NO _x reduction in an exhaust stream.

BACKGROUND

[0002] Compression ignition engines provide advantages in fuel economy, but produce both NO _x and particulates during normal operation. New and existing regulations continually challenge manufacturers to achieve good fuel economy and reduce the particulates and NO _x emissions. Lean-burn engines achieve the fuel economy objective, but the high concentrations of oxygen in the exhaust of these engines yields significantly high concentrations of NO _x as well. Accordingly, the use of NO _x reducing exhaust treatment schemes is being employed in a growing number of systems.

[0003] One such system is the direct addition of ammonia gas to the exhaust stream in conjunction with an after-treatment device. It is an advantage to deliver ammonia directly in the form of a gas, both for simplicity of the flow control system and for efficient mixing of reducing agent, ammonia, with the exhaust gas. The direct use of ammonia also eliminates potential difficulties related to blocking of the dosing system, which are cause by precipitation or impurities, e.g., in a liquid-based urea solution. In addition, an aqueous urea solution cannot be dosed at a low engine load since the temperature of the exhaust line would be too low for complete conversion of urea to ammonia (and C0 ₂ ).

[0004] Transporting a reductant, such as ammonia, as a pressurized liquid, however, can be hazardous if the container bursts caused by an accident or if a valve or tube breaks. In the case of using a solid storage medium, the safety issues are much less critical since a small amount of heat is required to release the ammonia and the equilibrium pressure at room temperature can be— if a proper solid material is chosen— well below 1 bar. An ammonia adsorbing/desorbing material in a granular or powder form can be contained within disks or balls formed from aluminum and loaded into the cartridge or canister. The canisters are then positioned in a heating unit, such as a heating jacket, which is then loaded into a housing or other storage structure and secured to the vehicle for use. Appropriate heat is applied to the canisters through the heating jackets, which then causes the ammonia-containing storage material to release its ammonia gas into an after-treatment device for use in the reduction of NO _x in an exhaust system. The present device provides a deep drawn, high compaction canister for ammonia-storage material.

SUMMARY

[0005] There is disclosed herein a device and method, each of which avoids the disadvantages of prior devices, systems and methods while affording additional structural and operating advantages.

[0006] Generally speaking, a deep-drawn, high compaction canister for storing an ammonia adsorbing/desorbing material for use in the reduction of NO _x in an exhaust after-treatment device, is disclosed. The canister comprises a main body having a closed bottom and defining an interior space, the main body being constructed from a singular piece of material, an ammonia storage material contained within the interior space, a connection port for accessing the material within the interior space and, at least one handle on the main body.

[0007] In another embodiment, the main body of the canister is seamless.

[0008] In another embodiment, a compact canister is disclosed. The compact canister comprises a deep-drawn, one-piece cylindrical body having an interior space, a pair of opposing handles, a connection port for accessing the interior space and coupling to an ammonia feed line which is further connected to an exhaust after-treatment device for a vehicle.

[0009] These and other aspects of the device and method may be understood more readily from the following description and the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 is a schematic of an ammonia storage and delivery system (ASDS) including several peripheral components;

[0011] FIG. 2 is a perspective view of the present canister within a heating jacket and housing;

[0012] FIG. 3 is a perspective front view of an embodiment of the present canister; [0013] FIG. 4 is a side view of an embodiment of the present canister; and,

[0014] FIG. 5 is a close-up view of the present canister showing the ammonia delivery line and connection port.

DETAILED DESCRIPTION

[0015] Referring to FIG. 1, there is illustrated the general components of an ammonia storage and dosing system (ASDS) 40 and an exhaust gas NO _x reduction (EGNR) system 50. The ASDS 40 involves delivery of a reductant, such as gaseous ammonia to an after-treatment assembly 60, which is used in the reduction of NO _x in an engine exhaust gas stream as part of the EGNR system 50 found on combustion engine vehicles. The ASDS 40 is comprised of several components, including at least one ammonia-containing main canister 10, an ammonia- containing start-up canister 12, a housing or storage compartment 16 for storing the main canister or canisters, an ammonia flow module (AFM) 18, a peripheral interface module (PIM) 20, and possibly other components depending on vehicle specifications.

[0016] In addition to the ASDS 40, the EGNR 50 comprises a vehicle engine 22 and an engine exhaust after-treatment assembly 60. The specific components of the ASDS 40 and EGNR will not be discussed in further detail with the exception of discussing, as necessary, how a component or system may relate to the present device. Further, as the vehicle ignition system and the vehicle exhaust system, including those used on a diesel engine vehicle, are well-known, these systems also will not be described in detail.

[0017] As shown in FIG. 2, the assembly for storing the ammonia adsorbing/desorbing material primarily comprises a canister 10 positioned within a heating jacket 24, which is then loaded into a housing 16. As illustrated in FIG. 3, the canister 10, also known as a container or cartridge, can have any suitable shape, but is typically a one-piece, cylindrical shape, having a hollow space or interior therein. A one-piece canister is preferred as there is minimal risk of leakage if the canister is constructed as one-piece, rather than as two or more pieces requiring seaming together. The canister 10 can be constructed as deep-drawn container from any suitable material that is sturdy for loading and transporting the material. In addition, the material for constructing the canister 10 should ideally conduct and retain heat, because the ammonia- containing material used in an exhaust after-treatment assembly requires heat to desorb ammonia gas from the material. Aluminum sheets are a suitable material for use in constructing the canister 10 in a known manner. Aluminum alloys, stainless steel, metal alloys, and other known suitable materials may also prove useful in the production of the desired canister. [ANY

OTHER SUITABLE MATERIALS FOR CONSTRUCTING THE CANISTER?]

However, as aluminum has a low mass density and excellent thermal conductivity, it is a preferred material. In addition to canister material, other factors for conducting a metal deep draw process, such as material thickness, tooling, punch speed, lubrication, radii, draw ratio, etc., must be considered. [IF ANY OF THE DETAILS OF THE PROCESS, AND

SPECIFICATIONS CONCERING THE CANISTER, SUCH AND LENGTH, WALL THICKNESS, ETC., THIS INFORMATION SHOULD BE ADDED] . Those skilled in the art will understand from the present disclosure how to address each of these, as well as many other necessary factors without undue experimentation.

[0018] The canister 10 may be constructed from a single layer of material or multiple layers. Deep draw manufacturing results in a seamless canister having a closed bottom, which is suitable for the storage of ammonia-containing material and the subsequent release of ammonia gas from the material. Additionally, the canister 10 may have a double-walled construction, and include a built-in heating element.

[0019] The ammonia-storage or ammonia adsorbing/desorbing material may have any suitable shape, including as a disk, which is convenient for loading into the canister. The ammonia-storage material may also be in the form of compressed granules or a tight-packed powder. In addition, the material, particularly in a granular form, may have sheets or pieces of metal dispersed throughout the material, which increases the thermal conductivity of the material. For example, aluminum covered balls of material may be loaded into the canister, and then tightly compressed, rupturing the balls resulting in a random material/sheet metal distribution of material within the canister. Regardless of the technology used to prepare the material, and load it into the canister for use, it is important to prevent the dissipation of ammonia during the formation of the material.

[0020] Suitable reductant or ammonia adsorbing/desorbing material for use in the present canister 10 include metal-ammine salts, which offer a solid storage medium for ammonia, and represent a safe, practical and compact option for storage and transportation of ammonia. Ammonia may be released from the metal ammine salt by heating the salt to temperatures in the range from 10°C to the melting point to the metal ammine salt complex, for example, to a temperature from 30° to 700°C, and preferably to a temperature of from 100° to 500°C. Generally speaking, metal ammine salts useful in the present device include the general formula M(NH ₃ ) _n X _z , where M is one or more metal ions capable of binding ammonia, such as Li, Mg, Ca, Sr, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, etc., n is the coordination number usually 2-12, and X is one or more anions, depending on the valence of M, where representative examples of X are F, CI, Br, I, S0 ₄ , M0O ₄ , P0 ₄ , etc. Preferably, ammonia saturated strontium chloride, Sr(NH ₃ )Cl _2, is used. While embodiments using ammonia as the preferred reductant are disclosed, other reductants useful in the present application may include urea, ammonium carbamate and hydrocarbons including diesel fuel. [CORRECT?]

[0021] In order to accomplish sufficient heating of the canisters 10, the canisters are placed within a heating jacket 24. The heating jacket 24 is typically constructed of two, molded symmetrical halves or sections, a first housing section 25 and a second housing section 26, each of which are comprised of layered materials. By way of example, the layered materials may include: an inner surface layer constructed of a suitable heat conductive and durable material, such as aluminum; a heating element layer constructed of a silicone encased resistive wire mesh; an insulation layer constructed of any suitable insulation material such as foam or fiberglass; and an outer shell layer constructed of any suitable durable material, such as a glass-filled polymer (nylon). The individual layers may be coextruded together, or optionally, the inner layer, heating element layer and insulation layer may be formed as a single sheet composite, which is then secured to the outer layer in a known manner.

[0022] The sections 25, 26 of the heating jacket are typically detachably connected together, or movably connected together to define an interior space or chamber (not shown) for receiving the canister 10. The sections 25, 26 are designed to open away from one another for seating or removing a canister within the interior chamber for heating. The sections may be pivotally attached to one another through known attachment means, such as hinges, at one end of the jacket, so that the sections open and close like a clamshell. Alternatively, rather than having the sections joined together for pivotal opening movement, the first section 25 can be lifted up and away completely from the second section 26 for insertion or removal of the canister.

[0023] Handling the canister 10, whether through insertion and removal of the canister 10 within the heating jacket 24, or simply carrying the canister, can be accomplished through use of at least one handle 28. Ideally, the handle 28 is integrally formed on one end of the canister. Alternatively, the handle or handles may be attached to the formed canister through known welding means. [PLEASE CONFIRM HOW THE HANDLES ARE

ATTACHED/FORMED TO THE CANISTER BODY] One embodiment of a handle useful for the present canister is shown in the FIG. 3. In this embodiment, the handle 28 may be located on the same end as the connection assembly 29. Alternatively, in another embodiment of the canister as shown in FIG. 4, the handle 102 may be a one-piece unit located on the end of the canister 100 opposite from the connection assembly 103. Regardless of the location and configuration, the handle should be easy to grip by the user. A pair of opposing handles 28 (FIG. 3) may be provided so the canister 10 can be evenly pulled out of and inserted into the heating jacket, and for ease of handling the canister in general. Additionally, the handle or handles 28, 102 may be shaped to prevent the canister from rolling, and may also help to index the canister within the heating jacket 24 for a uniform fit. Finally, the handles 28, 102 may be useful in engaging a latch (not shown) from the heating jacket to retain the canister within the heating jacket and prevent it from unintentionally sliding out during use.

[0024] As shown in FIG. 5, the canister 10 includes a connection assembly 29 positioned on one of the two ends of the canister. The connection assembly 29 provides a passage for the ammonia gas when it is released from the ammonia-storage material within the interior of the canister upon appropriate heating of the canister, ultimately for use in the after-treatment assembly 60. The connection assembly 29 includes an ammonia tap or connection port 30 formed as an integral part of the canister. The connection port 40 attaches to a coupler 32 and a fluid delivery line 34 (FIG. 2). The fluid delivery line 34 eventually leads to the after-treatment device 60, wherein the ammonia gas is used to reduce the level of NO _x in the exhaust stream.

[0025] FIG. 5 shows an embodiment of a coupler 32 useful in the present connection assembly 29. In this embodiment, the coupler 32 includes a male component 36 and a female component 38. The male component 36 and female component 38 are detachably connected to one another through a threaded connecting portion (not shown) of the male component, which engages a receptacle (not shown) of the female component. The male and female components may be engaged and disengaged through rotation of the canister, or a click-to-lock method.

Check valves (not shown) are positioned within each component to prevent any residual ammonia gas from either leaking out of the canister or leaking from the fluid line 34 connected to the rest of the system. [0026] Manufacturing a one piece deep-drawn product, such as the present canister, can be accomplished through known deep-drawn methods. [PLEASE CONFIRM THIS IS

DESCRIBED CORRECTLY] For example, deep drawn manufacturing typically includes a die, a die cavity in which the desired one-piece deep-drawn product is formed, a clamp for holding the product blank against a surface of the die, and a mandrel or draw punch used to force portions of the product blank into the die cavity during the drawing and/or ironing operation that forms the desired one-piece finished product. The product blank is positioned over the die cavity opening and the clamp exerts a calculated force that slidably clamps the product blank to a surface of the die adjacent the die cavity opening. The clamping force is calculated so that when the mandrel is extended to force the product blank into the die cavity during the drawing and/or ironing operation, the product blank portion that is slidably clamped between the die and clamp, slides between the two surfaces to provide a controlled feed of blank material into the die cavity during the drawing operation. In the present application, the canister formed from this method is a deep-drawn, high compaction canister durably constructed for the storage of an ammonia adsorbing/desorbing material, and suitable for heating to release ammonia gas for use in a NO _x reduction system.