WO2014003718A1

WO2014003718A1 - Modular exhaust treatment system

Info

Publication number: WO2014003718A1
Application number: PCT/US2012/044173
Authority: WO
Inventors: Gregory A. Griffin; Timothy Yoon; Jeffrey R. Kelso; Adam C. Lack; Jason B. ARRIAGA; Ramon A. Mella
Original assignee: International Engine Intellectual Property Company, Llc
Priority date: 2012-06-26
Filing date: 2012-06-26
Publication date: 2014-01-03

Abstract

Storage and delivery of ammonia for delivery to an exhaust after-treatment relate to an ammonia dosing system incorporating a self- contained, modular housing for receiving a variety of system components, including a canister or a plurality of canisters containing an ammonia storage material, wherein the canister can be connected to a common manifold for release of gaseous ammonia for use in ammonia dosing in the selective catalytic reduction of NOx in the exhaust stream of a vehicle. Other system components within the housing can include an ammonia flow control module and a peripheral interface module for controlling the flow of ammonia from the canisters into the after-treatment device. A second modular housing may be included in the system for containment of other system components. The modular housing can be positioned in any number of configurations depending in the requirements of the system.

Description

MODULAR EXHAUST TREATMENT SYSTEM

TECHNICAL FIELD

[0001] The present system and method relate to the storage and delivery of ammonia. Particularly, the system and method relate to an ammonia storage and delivery system incorporating a modular unit for containing various combinations of system components, including a canister storing an ammonia adsorbing/desorbing material, for use in the release of gaseous ammonia for selective catalytic reduction of NO_x in the exhaust stream of a vehicle.

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. 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 CO₂).

[0004] Transporting 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 or granular 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 material is chosen— well below 1 bar. Ammonia storage material can be provided in the form of disks, balls or granulated material loaded into the cartridge or canister. The canisters are then loaded into a mantle housing or other storage device and secured to the vehicle for use. Appropriate heat is applied to the canisters, which then causes the ammonia-containing storage material to release its ammonia gas into the exhaust system of a vehicle, for example.

[0005] Ammonia storage and dosing systems (ASDS), which are part of the exhaust gas Οχ reduction (EGNR) system used in vehicles, may be comprised of several components, including a start-up canister, at least one main canister, an ammonia control module (AFM), a peripheral interface module (PIM), and possibly other components depending on vehicle specifications. Incorporating all of these components into a vehicle system may be difficult depending on certain requirements, including separate placement of components to maintain the desired weight distribution on a vehicle. In addition, because it is not practical to design a unique packaging system for each vehicle application, the present system offers a modular units such that the orientation/configuration of the various components can be varied.

SUMMARY

[0006] There is disclosed herein a system and method, each of which avoids the disadvantages of prior systems and methods while affording additional structural and operating advantages.

[0007] Generally speaking, the system and method relate to an ammonia storage and delivery system incorporating an assembly of modular units containing components of the ASDS, including at modular housing adapted for receiving at least one canister therein, a start-up canister, and an AFM and PIM, or various combinations of these components. The modular housing can be positioned in a variety of configurations.

[0008] In one embodiment, a modular housing system for storing and dispensing ammonia for use in a vehicle exhaust after-treatment device, is disclosed. The system comprises a first modular unit having an interior for receiving at least one main canister containing an ammonia adsorbing/desorbing material, and, a second modular unit having an interior for receiving a plurality of control modules and a start-up canister containing a solid ammonia-containing material. The control modules include an AFM and a PIM.

[0009] In another embodiment, a modular system for storing and dispensing ammonia for use in a vehicle exhaust after-treatment device, is disclosed. The system comprises a first modular unit having an interior adapted for receiving at least one main canister for storing an ammonia- containing material and a plurality of control modules, and a second modular unit adapted for receiving a start-up canister for storing a ammonia-containing material, the second modular unit attached to an outside surface of the first modular unit. Alternatively, the second modular unit may be positioned a distance away from the first modular unit. The control modules include an AFM and a PIM.

[0010] In yet another embodiment, a modular system for storing and dispensing ammonia for use in a vehicle exhaust after-treatment device, is disclosed. The system comprises a first housing capable of multiple orientations with an interior for receiving: at least one main canister containing an ammonia adsorbing/desorbing material; an ammonia flow module; and, a peripheral interface module, wherein the main canister, ammonia flow control module and the peripheral interface module are all fluidly connected to one another. The system also includes a second housing adapted for receiving a start-up canister containing an ammonia adsorbing/desorbing material, the second housing positioned on an outside surface of the first housing, wherein, the start-up canister, ammonia flow control module and the peripheral interface module are all fluidly connected to one another.

[0011] These and other embodiments and their advantages can be more readily understood from a review of the following detailed description and the corresponding appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 is a schematic view of an exhaust gas NO_x reduction (EGNR) system incorporating the present ASDS system;

[0013] FIG. 2 is an exploded view of an embodiment of the modular canister housing arrangement of the present system;

[0014] FIG. 3 is an assembled view of the embodiment of the modular canister housing arrangement of the present system;

[0015] FIG. 4 is another embodiment of the modular canister housing arrangement of the present system;

[0016] FIG. 5 is another embodiment of the modular canister arrangement of the present system;

[0017] FIG. 6 is another embodiment of the modular canister housing arrangement of the present system;

[0018] FIG. 7 is another embodiment of the modular canister housing arrangement of the present system; and,

[0019] FIG. 8 is yet another embodiment of the modular canister housing arrangement of the present system. DETAILED DESCRIPTION

[0020] Referring to FIGS. 1-8, there is illustrated a modular system and method for storage of ammonia, specifically in a solid form, and delivery of gaseous ammonia for use in the reduction of NO_x in an exhaust stream. FIG. 1 illustrates an exhaust gas NO_x reduction system (EGNR), including an ammonia storage and dosing or delivery systems (ASDS).

[0021] The ASDS may be comprised of several components, including generally a housing 12 having a main canister 14 or a plurality of canisters, a start-up canister 16, an ammonia control module (AFM) 20, which regulates the flow of ammonia into the exhaust stream from the canisters, and a peripheral interface module (PIM) 22, which contains controls and diagnostics for the system, and interfaces with the electronic control module (ECM) 23. All of these components are incorporated into the present modular system 10. The specific operation and details of the ECM, the AFM and PIM, which control the flow of ammonia from the start-up canisters and main canisters to the after-treatment device, are known and will not be discussed in detail here. The remaining components of the EGNR, including the after-treatment device, will not be discussed in further detail with the exception of how they relate to the present system. As the exhaust system of a vehicle (not shown), including that of a diesel engine, is well known, it also will not be described in detail.

[0022] As shown in FIGS. 2-8, the present system 10 is a modular system for the ASDS components. Because it is not practical to design unique packaging for the components for each application, use of the present modular system 10, which can be positioned into a variety of configurations, provides an efficient, compact and cost-effective way to incorporate the ASDS components into any vehicle or application.

[0023] As shown in FIG. 2, the modular system 10 includes a first modular unit or housing 12 having an interior 12a. In one embodiment, the first unit or housing 12 can be used for storing the main canister 14 or canisters. In another embodiment, the first unit or housing may also be used to store additional components of the ASDS, including the AFM 20 and the PIM 22. The first housing 12 can have any suitable shape for receiving the canisters, but is typically rectangular or square. The housing can be sealed with a door 12b, pivotally attached to the housing by known means. The housing 12 can be constructed from any durable material, such as steel, aluminum or plastics, and can be secured, using known attachment means, to the frame of a vehicle (not shown), for retention on the vehicle during use. [0024] The first housing 12 is a modular unit, constructed with standardized dimensions for use in a variety of applications, yet providing flexibility in the number of canisters that can be installed therein. Ideally, the housing 12 is constructed based on industry standards such that it will fit within any vehicle, while providing the option for installation of any number of canisters 14 within the housing. As shown in FIGS. 3-5, the first housing 12 can be adapted for receiving from one up to three or more canisters 14, depending on application requirements. In another embodiment, shown in FIGS. 6 and 7, the first housing can contain any number of canisters, while accommodating other components of the ASDS system, such as the AFM and PIM in another section 12c of the same housing. In addition, the housing 12 can be positioned in a variety of orientations, depending on the use requirements and positioning of the canisters and other components within the vehicle. For example, FIGS, 3-7 show various vertical and horizontal configurations, in addition to a variation in the number of canisters within each unit. These various modular housing configurations make the present system a cost-effective, semi-customizable unit.

[0025] Seated within the interior of the housing 12 is at least one main canister (also sometimes referred to as a cartridge or container) 14, which serve as storage units for an ammonia adsorbing/desorbing containing material (not shown). Ammonia adsorbing/desorbing material useful in the present system includes a metal ammine salt. It has been found that the ammine salt is best having the general formula M( H₃)_nX_z, where M is one or more metal ions selected from the group consisting of Li, Mg, Ca, Sr, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn, n is the coordination number in the range of from 2 to 12, and X is one or more anions, depending on the valence of M, selected from the group consisting of F, CI, Br, I, S0₄, M0O₄, and PO₄. A saturated strontium chloride has been found to be preferable for the canister storage space.

[0026] The canisters 14 can have any useable shape, including a cylindrical shape, and may be constructed from any suitable material that is durable for loading and transporting the ammonia-containing storage material (not shown). In addition, the material for constructing the canisters should ideally conduct heat, because the ammonia adsorbing/desorbing material used in the present system and method, require heat to gradually release the ammonia as a gas based on ammonia dosing demands. Aluminum sheets are a suitable material for use in constructing the canisters in a known manner. Aluminum has a low mass density and excellent thermal conductivity.

[0027] In one embodiment, positioning and securing the canisters 16 within the housing may be accomplished using a staging platform 24. As shown in FIG. 2, the canister or canisters 16 are positioned on the platform 24, and connected together through use of a common manifold 26. The common manifold 26 is the conduit through which the ammonia gas from the canisters 16 flows into the after-treatment device (not shown) and eventually into the exhaust stream. The platform 24 may also include a plurality of grooves 28, which assist in maintaining the canisters in position on the platform and in place within the housing. In this manner, once the canisters 16 are positioned on the platform 24, the entire platform can be slid into the interior of the housing 12.

[0028] Alternatively, the canisters 14 may be individually placed within the housing 12. FIGS. 3-7 illustrate various numbers of canisters within the single housing, and in a variety of orientations. The canisters 14 may be held in position using a rail structure (not shown) or other securing systems, such that the canisters stay in position regardless of the housing configuration.

[0029] The present system 10 incorporates a first or start-up canister 16. As shown in FIG. 1, the start-up canister 16 is significantly smaller than the main canister 14, typically, about one-half to one-third the size of the main canister 14. Because of its smaller size, the start-up canister 16 can heat more quickly than the main canisters 14, reaching the required temperature to release ammonia gas from the start-up canister and initiate the NO_x reduction process. The start-up canister 16 is especially useful during the start-up phase of the engine when the operating temperatures are still low, and the temperature has not reached a level to initiate release of ammonia gas from the main canisters 14. In addition, the smaller size of the start-up canister 16 permits it to cool faster than the main canisters 14, leading to faster re-charging of the ammonia adsorbing/desorbing material within the start-up canister with ammonia gas. Regardless of the modular embodiment of the present system, the start-up canister will always be located outside of the housing 12, either in close proximity thereto, or in another location on the vehicle.

[0030] In one embodiment (FIGS. 2 and 3-7), the start-up canister 16 is positioned in a second housing 30, which is either attached to an outside surface of the first housing 12 containing the main canister 14, or at a defined distance apart from the first housing. The second housing 30 may also function as a protective cover or shield. Locating the start-up canister away from the first housing and main canisters prevents the ammonia-containing material within the start-up canister from being affected by the heat generated from the main canisters. The start-up canister 16 also cools much faster than the main canisters because of its position away from the main canisters and its smaller size. Once the start-up canister 16 cools to a certain level, the ammonia-containing material within the canister can be replenished or recharged with ammonia gas

[0031] In another embodiment, as shown in FIG. 8, the start-up canister 16 and control modules, such as the AFM 20 and PIM 22 may be contained together within a second modular unit or housing unit 32. The second housing 32 may be positioned on an outside surface of the first housing 12, or alternatively, may be located in a completely different area of the vehicle. Regardless of the positioning of the housings and their various components, the canisters are fluidly connected to the AFM and PIM to ensure the required flow of ammonia gas is supplied to the after-treatment device and exhaust system.

Claims

Claims What is claimed is:

1. A modular system for storing and dispensing ammonia for use in a vehicle exhaust after-treatment device, the system comprising: a first modular unit having an interior for receiving at least one main canister containing an ammonia adsorbing/desorbing material; and, a second modular unit having an interior for receiving a plurality of control modules and a start-up canister containing ammonia adsorbing/desorbing material.

2. The modular system of claim 1, wherein the second modular unit is positioned separate from the first modular unit.

3. The modular system of claim 1, wherein the second modular unit is attached to an outside of the first modular unit.

4. The modular system of claim 1, wherein the control modules comprise an ammonia flow control module and a peripheral interface module.

5. The modular system of claim 4, wherein the ammonia flow control module and the peripheral interface module are fluidly connected to the start-up canister.

6. The modular system of claim 4, wherein the ammonia flow control module and the peripheral interface module are fluidly connected to the main canister.

7. A modular system for storing and dispensing ammonia for use in a vehicle after- treatment system, the system comprising: a first modular unit having an interior adapted for receiving at least one main canister for storing an ammonia-containing material and a plurality of control modules; and, a second modular unit adapted for receiving a start-up canister for storing the ammonia-containing material, the second modular unit attached to an outside surface of the first modular unit.

8. The modular system of claim 7, wherein the first modular unit includes multiple orientations for accommodating a variety of canister arrangements.

9. The modular system of claim 7, wherein the control modules comprise an ammonia flow control module and a peripheral interface module.

10. The modular system of claim 9, wherein the ammonia flow control module and the peripheral interface module are fluidly connected to the start-up canister.

1 1. The modular system of claim 9, wherein the ammonia flow control module and the peripheral interface module are fluidly connected to the main canister.

12. A modular system for storing and dispensing ammonia for use in a vehicle exhaust after-treatment device , the system comprising:

a first housing capable of multiple orientations having an interior for receiving: i. at least one main canister containing an ammonia adsorbing/desorbing material,

ii. an ammonia flow module, and,

iii. a peripheral interface module,

wherein the start-up canister, ammonia flow control module and the peripheral interface module are all fluidly connected to one another; and,

a second housing having an interior for receiving a start-up canister containing an ammonia adsorbing/desorbing material, the second housing positioned on an outside surface of the first housing, wherein the main canister, ammonia flow control module and the peripheral interface module are fluidly connected to one another.

13. The modular system of claim 12, wherein the second housing is a protective covering for the start-up canister.