阅读说明：本技术 用于将干化学还原剂导入后处理系统的系统和方法 (System and method for introducing dry chemical reductant into an aftertreatment system ) 是由 马修·K·沃尔默丁 克里斯托弗·T·布朗 尤利西斯·蒙德拉贡 文森特·麦克唐纳 于 2019-08-29 设计创作，主要内容包括：一种还原剂导入系统,用于被配置成分解废气中的成分的后处理系统,该还原剂导入系统包括：干还原剂箱,其被配置成容纳干还原剂；还原剂输送管线,其被配置成将干还原剂箱可操作地联接到后处理系统,以将干还原剂输送到后处理系统；以及加压气体源,其被配置成使用加压气体将干还原剂通过还原剂输送管线传送到后处理系统。(A reductant introduction system for an aftertreatment system configured to decompose a constituent in an exhaust gas, the reductant introduction system comprising: a dry reductant tank configured to contain a dry reductant; a reductant delivery line configured to operably couple the dry reductant tank to the aftertreatment system to deliver the dry reductant to the aftertreatment system; and a pressurized gas source configured to deliver the dry reductant to the aftertreatment system through the reductant delivery line using the pressurized gas.)

1. A reductant introduction system for an aftertreatment system configured to decompose a constituent in an exhaust gas, the reductant introduction system comprising:

a dry reductant tank configured to contain a dry reductant;

a reductant delivery line configured to operably couple the dry reductant tank to the aftertreatment system to deliver the dry reductant to the aftertreatment system; and

a pressurized gas source configured to deliver the dry reductant to the aftertreatment system through the reductant delivery line using a pressurized gas.

2. The reductant introduction system of claim 1, wherein the pressurized gas source includes a compressed gas that occupies a volume of the dry reductant tank and exerts pressure on the dry reductant.

3. The reductant introduction system of claim 2, further comprising a pressure relief valve operably coupled to the dry reductant tank, the pressure relief valve configured to open in response to a pressure within the dry reductant tank exceeding a predetermined pressure threshold.

4. The reductant introduction system of claim 2, further comprising a valve disposed in the reductant delivery line, the valve configured to be selectively opened to deliver a predetermined volume of the dry reductant to the aftertreatment system.

5. The reductant introduction system of claim 4, further comprising a pressure sensor integrated with the valve.

6. The reductant introduction system of claim 2, further comprising a shut-off valve coupled to an outlet of the dry reductant tank and configured to be selectively closed to prevent dry reductant from being transferred out of the dry reductant tank.

7. The reductant introduction system of claim 1, wherein the pressurized gas source comprises a compressed gas source coupled to the reductant delivery line and configured to provide compressed gas to the aftertreatment system through the reductant delivery line, and wherein the reductant introduction system further comprises:

a reductant delivery line operably coupling the dry reductant tank to the reductant delivery line; and

a dry reductant feeder coupled to the reductant delivery line and configured to deliver the dry reductant from the dry reductant tank to the reductant delivery line via the reductant delivery line.

8. The reductant introduction system of claim 7, further comprising an injector coupled to the reductant delivery line downstream of the reductant delivery line, wherein the pressurized gas source is coupled to the reductant delivery line via the injector, the injector configured to generate a suction force in the reductant delivery line to deliver the dry reductant to the aftertreatment system via the reductant delivery line.

9. The reductant introduction system of claim 8, wherein a first end of the reductant delivery line upstream of the reductant delivery line is open to atmosphere.

10. The reductant introduction system of claim 1, wherein the pressurized gas source includes an exhaust gas recirculation line coupled to a first end of the reductant delivery line, the pressurized gas is a recirculated exhaust gas and the reductant introduction system further comprises:

a reductant delivery line coupling the dry reductant tank to the reductant delivery line; and

a dry reductant feeder coupled to the reductant delivery line and configured to deliver the dry reductant from the dry reductant tank to the reductant delivery line via the reductant delivery line.

11. The reductant introduction system of claim 10, further comprising a heater configured to heat the recirculated exhaust gas to a temperature sufficient to substantially decompose the dry reductant.

12. The reductant introduction system of claim 10, further comprising a valve coupled to the exhaust gas recirculation line and configured to be selectively opened to communicate the recirculated exhaust gas to the reductant delivery line.

13. A reductant introduction system for an aftertreatment system configured to decompose a constituent in an exhaust gas, the reductant introduction system comprising:

a dry reductant tank configured to contain a dry reductant; and

a reductant delivery line configured to operably couple the dry reductant tank to the aftertreatment system to allow gravity-assisted delivery of the dry reductant from the dry reductant tank to the aftertreatment system.

14. The reductant introduction system of claim 13, further comprising:

a reductant delivery line operably coupling the dry reductant tank to the reductant delivery line; and

a dry reductant feeder coupled to the reductant delivery line and configured to deliver the dry reductant from the dry reductant tank to the reductant delivery line via the reductant delivery line.

15. The reductant introduction system of claim 13, wherein the dry reductant feeder comprises a screw feeder.

16. A method for introducing a dry reductant into an exhaust gas flowing through an aftertreatment system, the method comprising:

determining an operating condition of the exhaust gas;

a reductant delivery line that provides pressurized gas to a reductant introduction system, the reductant introduction system comprising:

a dry reductant tank containing a dry reductant,

a reductant delivery line operably coupling the dry reductant tank to the aftertreatment system, an

A source of pressurized gas for providing the pressurized gas; and

activating a dry reductant feeder of the reductant introduction system to deliver the dry reductant to the aftertreatment system via the reductant delivery line.

17. The method of claim 16, further comprising:

determining a temperature of the pressurized gas prior to providing the pressurized gas to the reductant delivery line; and

in response to the temperature being less than a temperature threshold, heating the pressurized gas to a temperature sufficient to decompose the dry reductant.

18. The method of claim 16, wherein the source of pressurized gas comprises a source of compressed gas.

19. The method of claim 16, wherein the pressurized gas source comprises a recycled exhaust gas source.

20. The method of claim 16, wherein the dry reductant feeder comprises a screw feeder.

Technical Field

The present disclosure relates generally to aftertreatment systems for Internal Combustion (IC) engines.

Background

An exhaust aftertreatment system is used to receive and treat exhaust gas produced by the IC engine. Generally, an exhaust aftertreatment system includes any of several different components to reduce the level of harmful emissions present in the exhaust gas. For example, certain exhaust aftertreatment systems for diesel-powered IC engines include Selective Catalytic Reduction (SCR) systems that include a catalyst formulated to react with ammonia (NH)₃) In the presence of NOx (in a certain percentage of NO and NO)₂) Conversion to harmless nitrogen (N)₂) And water vapor (H)₂O). Typically, in such aftertreatment systems, an exhaust reductant (e.g., a diesel exhaust fluid, such as a urea solution) is injected into the SCR system to provide a source of ammonia and mixed with the exhaust gas to partially reduce the NOx gases. The reduced byproducts of the exhaust gas are then passed to a catalyst included in the SCR system to decompose substantially all of the NOx gases into relatively harmless byproducts that are exhausted from the aftertreatment system.

SUMMARY

Exhaust gas reductants used in conventional aftertreatment systems typically include a liquid reductant that is introduced into or upstream of the SCR system. However, liquid reductants pose various challenges. For example, when a liquid reductant is introduced into an aftertreatment system, a stream of the liquid reductant may impinge on an interior surface of the aftertreatment system and form byproducts that form reductant deposits on the interior surface of the aftertreatment system. In addition, very low temperatures (e.g., less than-11 degrees Celsius) can cause the reductant to freeze in the reductant introduction assembly. This increases the cost of the aftertreatment system (due to the inclusion of a heating system, for heating the lines or electric heaters, for example), increases energy and fuel consumption, and results in increased maintenance costs. It is often necessary to include a heater in such reductant introduction assemblies to thaw the reductant under cold ambient conditions, which increases the complexity of the system. In addition, liquid reductant introduced into the aftertreatment system may impinge on sidewalls of the aftertreatment system, causing reductant deposits to form on the sidewalls and/or components of the aftertreatment system. Reductant deposits reduce the efficiency of the aftertreatment system and may lead to plugging and ultimately failure of the SCR system and/or downstream components. Reductant deposits result in frequent maintenance of the aftertreatment system, which increases maintenance costs. Alternative reductant deposit removal strategies include heating the exhaust gas to temperatures above 450 degrees celsius, for example, by introducing hydrocarbons into the exhaust gas. However, this increases fuel consumption.

The embodiments described herein relate generally to systems and methods for delivering dry reductant to an aftertreatment system, and more particularly to a reductant introduction system that allows gravity-assisted delivery of dry reductant or includes a pressurized gas source for assisted delivery of dry reductant gas into exhaust gas flowing through an aftertreatment system.

In one embodiment, a reductant introduction system for an aftertreatment system configured to decompose a constituent in an exhaust gas includes: a dry reductant tank configured to contain a dry reductant; a reductant delivery line configured to operably couple the dry reductant tank to the aftertreatment system to deliver the dry reductant to the aftertreatment system; and a pressurized gas source configured to deliver the dry reductant to the aftertreatment system through the reductant delivery line using the pressurized gas.

In some embodiments, the source of pressurized gas comprises a compressed gas that occupies a volume of the dry reductant tank and exerts pressure on the dry reductant.

In some embodiments, a pressure relief valve is operably coupled to the dry reductant tank, the pressure relief valve configured to open in response to a pressure within the dry reductant tank exceeding a predetermined pressure threshold.

In some embodiments, a valve is disposed in the reductant delivery line, the valve configured to selectively open to deliver a predetermined volume of dry reductant to the aftertreatment system. In some embodiments, the reductant introduction system further includes a pressure sensor integrated with the valve.

In some embodiments, a shut-off valve is coupled to an outlet of the dry reductant tank and is configured to be selectively closed to prevent dry reductant from being transferred out of the dry reductant tank.

In some embodiments, the pressurized gas source comprises a compressed gas source coupled to the reductant delivery line and configured to provide compressed gas to the aftertreatment system through the reductant delivery line. In such embodiments, the reductant introduction system further comprises: a reductant delivery line operably coupling the dry reductant tank to the reductant delivery line; and a dry reductant feeder coupled to the reductant delivery line and configured to deliver dry reductant from the dry reductant tank to the reductant delivery line via the reductant delivery line.

In some embodiments, the injector is coupled to the reductant delivery line downstream of the reductant delivery line. In such embodiments, the pressurized gas source is coupled to the reductant delivery line via an injector, and the injector is configured to generate a suction force in the reductant delivery line to deliver dry reductant to the aftertreatment system via the reductant delivery line.

In some embodiments, a first end of the reductant delivery line upstream of the reductant delivery line is open to atmosphere.

In some embodiments, the pressurized gas source comprises an exhaust gas recirculation line coupled to the first end of the reductant delivery line, the pressurized gas being recirculated exhaust gas. In such embodiments, the reductant introduction system further comprises: a reductant delivery line coupling the dry reductant tank to the reductant delivery line; and a dry reductant feeder coupled to the reductant delivery line and configured to deliver dry reductant from the dry reductant tank to the reductant delivery line via the reductant delivery line.

In some embodiments, the reductant introduction system further includes a heater configured to heat the recirculated exhaust gas to a temperature sufficient to substantially decompose the dry reductant.

In some embodiments, a valve is coupled to the exhaust gas recirculation line and configured to be selectively opened to communicate recirculated exhaust gas to the reductant delivery line.

In another embodiment, a reductant introduction system for an aftertreatment system configured to decompose a constituent in an exhaust gas includes: a dry reductant tank configured to contain a dry reductant; a reductant delivery line configured to operably couple the dry reductant tank to the aftertreatment system to allow gravity-assisted delivery of the dry reductant from the dry reductant tank to the aftertreatment system.

In some embodiments, a reductant delivery line operably couples the dry reductant tank to the reductant delivery line; and a dry reductant feeder coupled to the reductant delivery line and configured to deliver dry reductant from the dry reductant tank to the reductant delivery line via the reductant delivery line. In some embodiments, the dry reductant feeder comprises a screw feeder.

In some embodiments, a method for introducing dry reductant into an exhaust gas flowing through an aftertreatment system comprises: determining an operating condition (operating condition) of the exhaust gas; a reductant delivery line that provides pressurized gas to a reductant introduction system, the reductant introduction system comprising: a dry reductant tank containing a dry reductant, a reductant delivery line operatively coupling the dry reductant tank to the aftertreatment system, and a pressurized gas source for providing a pressurized gas; and activating a dry reductant feeder of the reductant introduction system to deliver dry reductant to the aftertreatment system via the reductant delivery line.

In some embodiments, the method further comprises: determining a temperature of the pressurized gas prior to providing the pressurized gas to the reductant delivery line; and in response to the temperature being less than the temperature threshold, heating the pressurized gas to a temperature sufficient to decompose the dry reductant. In some embodiments, the pressurized gas source comprises a source of compressed gas. In some embodiments, the pressurized gas source comprises a source of recycled exhaust gas. In some embodiments, the dry reductant feeder comprises a screw feeder.

It is to be understood that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided that such concepts do not contradict each other) are to be considered part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the inventive subject matter disclosed herein.

Brief Description of Drawings

The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. The present disclosure will be described with additional specificity and detail through the use of the accompanying drawings, it being understood, however, that these drawings depict only several embodiments in accordance with the disclosure and are therefore not to be considered limiting of its scope.

Fig. 1A is a schematic block diagram of an aftertreatment system according to an embodiment.

FIG. 1B is a schematic illustration of a spray gun assembly that may be used in the aftertreatment system of FIG. 1A, according to an embodiment.

FIG. 2 is a schematic block diagram of a control circuit that may include a controller of the aftertreatment system of FIG. 1A, according to an embodiment.

FIG. 3 is a schematic block diagram of a reductant introduction system, according to an embodiment.

FIG. 4 is a schematic block diagram of a reductant introduction system according to another embodiment.

FIG. 5 is a schematic block diagram of a reductant introduction system according to yet another embodiment.

FIG. 6 is a schematic block diagram of a reductant introduction system according to yet another embodiment.

Fig. 7 shows a graph of particle size versus decomposition time for dry urea granules.

Fig. 8 shows a graph of the decomposition times of urea particles and Diesel Exhaust Fluid (DEF) droplets having various sizes.

FIG. 9 is a schematic flow diagram of a method for introducing dry reductant into an aftertreatment system, according to an embodiment.

FIG. 10 is a schematic flow diagram of a method for introducing dry reductant into an aftertreatment system in accordance with another embodiment.

Throughout the following detailed description, reference is made to the accompanying drawings. In the drawings, like numerals generally identify like components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not intended to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and make part of this disclosure.

Detailed Description

The embodiments described herein relate generally to systems and methods for delivering dry reductant to an aftertreatment system, and more particularly to a reductant introduction system that allows gravity-assisted delivery of dry reductant or includes a pressurized gas source for assisted delivery of dry reductant gas into an exhaust gas flowing through the aftertreatment system.

Liquid reductants are typically used to promote decomposition of exhaust gas flowing through an SCR system. However, the liquid reductant may impinge on the interior surfaces of the aftertreatment system and form byproducts that form reductant deposits on the interior surfaces of the aftertreatment system, while very low temperatures (e.g., less than-11 degrees celsius) may cause the reductant to freeze in the reductant introduction assembly. This results in increased maintenance costs. It is often necessary to include a heater in such reductant introduction assemblies to thaw the reductant under cold ambient conditions, which increases the complexity and cost of the system. Reductant deposits reduce the efficiency of the aftertreatment system and can cause plugging and ultimately failure of the SCR system and/or downstream components. Reductant deposits result in frequent maintenance of the aftertreatment system, thereby increasing maintenance costs.

Various embodiments of the reductant introduction system described herein may provide one or more benefits, including, for example: (1) introducing dry reductant into the aftertreatment system instead of liquid reductant, which prevents problems associated with decomposition or freezing of the liquid reductant within the reductant introduction system; (2) eliminating the use of heated lines for thawing the reductant, or eliminating pumps and/or filters typically used in liquid reductant introduction systems, thereby reducing system complexity and cost; (3) reducing the decomposition energy by removing water from the reducing agent; (4) significantly reducing the risk of deposition and providing faster decomposition times, resulting in faster ammonia release, improved turbulent diffusion and higher Uniformity Index (UI) relative to liquid reductants; (5) enabling a reduction in storage space and weight of about 50% or more relative to storage space for liquid reductant; (6) by providing the dry reducing agent in a stable powder form relative to the gaseous reducing agent that may leak, significantly higher safety is provided relative to the gaseous ammonia introduction system; and (7) provide flexibility in using various dry reductants, such as powdered urea, ammonium carbonate (ammonium carbonate), ammonium carbamate, or any other suitable dry reductant.

Fig. 1A is a schematic diagram of an aftertreatment system 100, according to an embodiment. The aftertreatment system 100 is coupled to an engine 10 (e.g., a diesel engine, a gasoline engine, a natural gas engine, a biodiesel engine, a dual fuel engine, an alcohol engine, E85, a reciprocating engine, a rotary engine, a gas turbine, or any other suitable internal combustion engine) and is configured to receive exhaust gas (e.g., diesel exhaust gas) from the engine 10 to reduce constituents in the exhaust gas, such as, for example, NOx gases, CO, and the like. The aftertreatment system 100 includes: a reductant introduction system 120 including a dry reductant tank 122 and a pressurized gas source 110, an SCR system 150, and a controller 170.

The SCR system 150 includes a housing 152 defining an interior volume in which is positioned at least one catalyst 154 configured to decompose constituents in exhaust gas flowing therethrough. The housing 152 may be formed from a rigid, heat resistant, and corrosion resistant material, such as stainless steel, iron, aluminum, metal, ceramic, or any other suitable material. The housing 152 may have any suitable cross-section, such as circular, square, rectangular, oval, ellipsoidal, polygonal, or any other suitable shape.

As described herein, in some embodiments, the SCR system 150 may include a Selective Catalytic Reduction Filter (SCRF) system or any other aftertreatment component configured to decompose constituents (e.g., NOx gases, such as, for example, nitrous oxide, nitric oxide, nitrogen dioxide, etc.) in the exhaust gas flowing through the aftertreatment system 100 in the presence of a reductant.

Although fig. 1A only shows the SCR system 150 positioned within the interior volume defined by the housing 152, in other embodiments, a plurality of aftertreatment components may be positioned within the interior volume defined by the housing 152 in addition to the catalyst 154. Such aftertreatment components include, for example, filters (e.g., particulate matter filters, catalytic filters, etc.), oxidation catalysts (e.g., carbon monoxide, hydrocarbon, and/or ammonia oxidation catalysts), mixers, baffles, or any other suitable aftertreatment component.

The catalyst 154 is configured to selectively decompose components in the exhaust gas. Any suitable catalyst may be used, such as a catalyst based on platinum, palladium, rhodium, cerium, iron, manganese, copper, vanadium, any other suitable catalyst, or combinations thereof. The catalyst 154 may be disposed on a suitable substrate, which may, for example, define a honeycomb structure, such as, for example, a ceramic (e.g., cordierite) or a metallic (e.g., chrome aluminum cobalt refractory steel (kanthal)) monolithic core. The washcoat may also be used as a support material for the catalyst 154. Such washcoat materials may include, for example, alumina, titania, silica, any other suitable washcoat material, or combinations thereof. Exhaust gas (e.g., diesel exhaust) may flow over and/or around the catalyst 154 such that any NOx gases included in the exhaust gas are further reduced to produce an exhaust gas that is substantially free of NOx gases.

The inlet conduit 102 is coupled to an inlet of the housing 152 and is configured to receive exhaust gases from the engine 10 and deliver the exhaust gases to an interior volume defined by the housing 152. Further, the outlet conduit 104 may be coupled to an outlet of the housing 152 and configured to discharge the treated exhaust gas into the environment. A first sensor 103 is positioned in the inlet duct 102. The first sensor 103 may include a NOx sensor configured to measure an amount of NOx gas included in the exhaust gas flowing into the SCR system 150, and the first sensor 103 may include a physical NOx sensor or a virtual NOx sensor. In various embodiments, a temperature sensor, a pressure sensor, or any other sensor may also be positioned in the inlet duct 102 to determine one or more operating conditions of the exhaust gas flowing through the aftertreatment system 100.

A second sensor 105 may be positioned in the outlet duct 104. The second sensor 105 may include a second NOx sensor configured to determine an amount of NOx gases in the exhaust gas that is emitted into the environment after passing through the SCR system 150. In other embodiments, the second sensor 105 may include an ammonia sensor configured to measure an amount of ammonia in the exhaust gas flowing from the SCR system 150, i.e., determine ammonia slip. This may be used as a measure to determine the catalytic efficiency of the SCR system 150, to adjust the amount of reductant to be introduced into the SCR system 150, and/or to adjust the temperature of the SCR system 150 to allow the SCR system 150 to efficiently use ammonia for catalytically decomposing NOx gases included in the exhaust gas flowing through the SCR system. An ammonia oxide (AMOx) catalyst may be positioned downstream of the SCR system 150, for example in the outlet duct 104, to decompose any unreacted ammonia in the exhaust gas downstream of the SCR system 150.

The reductant port 156 may be positioned on the inlet conduit 102 and configured to allow introduction of dry reductant into the flow path of the exhaust gas flowing through the inlet conduit 102. As shown, the reductant port 156 is positioned upstream of the SCR system 150 (e.g., to allow reductant to be introduced into the exhaust gas upstream of the SCR system 150). In other embodiments, a reductant port 156 may be defined in the housing 152, for example, to deliver reductant upstream of or onto the SCR system 150.

The reductant introduction system 120 includes a dry reductant tank 122 that contains dry reductant, and a pressurized gas source 110. The dry reductant tank 122 may include a sealed container configured to store dry reductant. Any suitable dry reducing agent may be used. In some embodiments, the dry reductant may include powdered urea, ammonia carbonate, ammonium carbamate, any other suitable ammonium salt with small particulate dry reductant, or a combination thereof. In various embodiments, additives such as flow agents and/or anti-caking agents may be included in the dry reducing agent (e.g., mixed with the powdered urea) to help maintain the reducing agent quality and/or to aid in the flow of the reducing agent. Other additives may include, for example, dehydrating agents (e.g., silica) to absorb moisture and prevent caking of the dry reductant powder. Any additives included in the dry reductant may be compatible with the downstream SCR system 150 and have minimal impact on exhaust emissions. In other embodiments, a moisture absorbent (e.g., silica gel) may be positioned within the dry reductant tank 122 separate from the dry reductant. For example, the moisture absorbent may be placed in a breathable bag within the dry reductant tank 122, or in a chamber defined in the dry reductant tank 122. For example, when refilling the dry reductant tank 122, the moisture absorbent may be replaced with a new moisture absorbent.

In some embodiments, the particles of dry reducing agent used in reducing agent introduction system 120 may have a diameter in the range of 1-100 microns. In particular embodiments, the particles of dry reductant used in reductant introduction system 120 may have diameters in the range of 10-30 microns. In various embodiments, the dry reductant tank 122 may be a removable tank that may be replaced with a new tank once the dry reductant in the dry reductant tank 122 is consumed. In other embodiments, dry reductant tank 122 may include a refillable tank that may be refilled with dry reductant once the amount of dry reductant in dry reductant tank 122 falls below a predetermined threshold.

The reductant delivery line 130 operably couples the dry reductant tank 122 to the SCR system 150. For example, as shown in fig. 1A, the reductant delivery line 130 is coupled to the reductant port 156 and is configured to deliver dry reductant into the flow path of the exhaust gas flowing through the inlet conduit 102. In various embodiments, a nozzle or orifice (not shown) may be disposed in the reductant port 156, the reductant port 156 being shaped and sized to direct an aerosol containing dry reductant particles into the exhaust flow path. Further, the valve 124 or a dry reductant feeder (e.g., the dry reductant feeder 324 described herein) may be coupled to the dry reductant tank 122 and/or the reductant delivery line 130, with or without the use of an injector (e.g., the injector 540), to selectively deliver dry reductant to the inlet conduit 102 via the reductant delivery line 130.

In some embodiments, reductant delivery line 130 and/or a nozzle or orifice disposed in reductant port 156 may have heat shielding or cooling features to prevent thermal degradation of dry reductant (e.g., dry urea) that may produce undesirable byproducts (e.g., biuret, triuret, and/or cyanuric acid). Such features may include, for example, thermal barriers, vacuum insulation, and/or air cooling features may be provided on the reductant delivery line 130, and/or on the nozzle or orifice to provide thermal shielding thereto. For example, the nozzle may comprise a vacuum insulated lance, and in some embodiments, the nozzle may also be air cooled. Alternatively, design features may be incorporated to prevent heat transfer from the exhaust gas to the nozzle and/or the reductant delivery line, including but not limited to a thermal barrier, thermal barrier coating, and/or to reduce the surface area of the nozzle or reductant delivery line 130 in the exhaust gas flow upstream of the nozzle.

For example, FIG. 1B is a schematic illustration of a spray gun assembly 180a that may be used in the reductant introduction system 120, or any other reductant introduction system described herein, to introduce dry reductant into the exhaust flowing through the aftertreatment system 100. Spray gun assembly 180a may be disposed in reductant port 156 or disposed through reductant port 156. Spray gun assembly 180a includes a spray gun 182a disposed within a hollow sheath 186 a. The hollow sheath 186a may comprise, for example, a hollow tube disposed circumferentially about the lance 182 a.

End 184a of lance 182a is fluidly coupled to or disposed through an outlet 188a defined in shroud 186 a. The end 184a may define a nozzle or orifice through which a flow of reductant is directed into the exhaust passing through the aftertreatment system 100. Although fig. 1B shows end 184a of lance 182a and outlet 188a at an axial end of lance assembly 180, in other embodiments lance 182a may include a bend, such as a 90 degree bend, such that end 184a is positioned at an angle relative to the longitudinal axis of lance assembly 180 a. In such embodiments, outlet 188a passes through a radial sidewall defined in shroud 186a such that reductant is introduced through end 184a of lance 182a at an angle (e.g., an angle of about 90 degrees) relative to a longitudinal axis of lance assembly 180 a.

The sheath 186a can define a first opening 185a, for example, through a radial sidewall thereof. In some embodiments, the opening 185a may be coupled to a vacuum source configured to draw air from the interior volume defined by the sheath 186a in order to create a vacuum around the lance 182a and provide a vacuum heat shield. In other embodiments, a gas source (e.g., a compressed air source) may be fluidly coupled to the first opening 185a and configured to deliver gas (e.g., air) into the jacket 186a to cool the lance 182 a. In such embodiments, a second opening 187a can also be defined in the sheath 186a (e.g., in a radial sidewall of the sheath) and configured to allow gas (which may be heated within the sheath) to pass out of the sheath 186 a. The heated gas may be cooled and recirculated back into the jacket 186a via the first opening 185 a.

In some embodiments, the reductant introduction system 120 is configured to allow gravity-assisted delivery of dry reductant from a dry reductant tank to the SCR system 150. For example, the dry reductant tank 122 may be disposed at a relatively high elevation relative to the SCR system 150. Valve 124 may be coupled to dry reductant tank 122 or reductant delivery line 130. Valve 124 is opened for a predetermined time to allow a predetermined amount (e.g., mass) of dry reductant to be delivered into SCR system 150 via reductant delivery line 130.

In other embodiments, the pressurized gas source 110 is located within or operably coupled to the dry reductant tank 122 and is configured to deliver or propel the dry reductant into the SCR system 150 using a pressurized gas (e.g., dry air, dry nitrogen, or recirculated exhaust gas). The pressurized gas may entrain particles of the dry reductant (e.g., form an aerosol) and propel the dry reductant into the exhaust flow path.

Any suitable source of pressurized gas may be used. In some embodiments, the pressurized gas source includes a compressed gas that occupies a volume of the dry reductant tank 122 and exerts pressure on the reductant. For example, FIG. 3 is a schematic diagram of a reductant introduction system 220 that may be used in aftertreatment system 100, according to an embodiment. The reductant introduction system 220 includes a dry reductant tank 222 that contains a volume of dry reductant 225. A portion 227 of the interior volume of the dry reductant tank 222 is filled with a compressed gas (e.g., dry air or dry nitrogen) that exerts pressure on the dry reductant.

In some embodiments, a compressed gas source 210 (e.g., a tank of compressed gas) may be coupled to the dry reductant tank 222 via a compressed gas line 212 and configured to provide compressed gas into the interior volume of the dry reductant tank 222. In some embodiments, a pressure relief valve 216 (e.g., a check valve) may be operably coupled to dry reductant tank 222. Pressure relief valve 216 may be configured to open in response to the pressure in dry reductant tank 222 exceeding a predetermined pressure threshold, and thus prevent the pressure within dry reductant tank 222 from increasing too much.

Reductant delivery line 230 operably couples dry reductant tank 222 to inlet conduit 202 (e.g., inlet conduit 102 of aftertreatment system 100). The nozzle 238 is positioned within the inlet conduit 202. The end of reductant delivery line 230 distal from dry reductant tank 222 is coupled to nozzle 238 and delivers compressed gas with entrained dry reductant particles to nozzle 238. The nozzle 238 may be shaped and sized to direct an aerosol of dry reductant and compressed gas into the exhaust gas flowing through the inlet conduit 202.

In some embodiments, a pressure sensor 232 is coupled to reductant delivery line 230 and is configured to measure a pressure of the compressed gas-dry reductant mixture flowing through reductant delivery line 230. Further, a valve 234 may also be disposed in the reductant delivery line 230. Valve 234 is configured to selectively open to deliver a predetermined volume of dry reductant to inlet conduit 202 (e.g., inlet conduit 102 of aftertreatment system 100). In certain embodiments, the pressure sensor 232 may be integrated with the valve 234.

In some embodiments, the reductant introduction system 220 may also include a shut-off valve 218. A shut-off valve may be coupled to an outlet of dry reductant tank 222 or reductant delivery line 230 and configured to selectively close to prevent dry reductant from being transferred out of dry reductant tank 222, e.g., in response to a safety issue (e.g., a leak in reductant delivery line 230 or dry reductant tank 222).

Referring again to fig. 1A, in some embodiments, the pressurized gas source 110 may include a source of compressed gas coupled to a first end of the reductant delivery line 130 and configured to provide the compressed gas to the SCR system 150 via the reductant delivery line. In such embodiments, the reductant introduction system 120 may also include a reductant delivery line that operably couples the dry reductant tank 122 to the reductant delivery line 130. The dry reductant feeder may be coupled to the reductant delivery line and configured to deliver dry reductant from the dry reductant tank 122 to the reductant delivery line 130 via the reductant delivery line. In some embodiments, the dry reductant feeder may also be configured to prevent compressed gas from flowing upstream thereof to the dry reductant tank 122. In other embodiments, dry reductant may be introduced into reductant delivery line 130 with the source of pressurized gas deactivated. Once a predetermined amount of dry reductant has been delivered to reductant delivery line 130, pressurized gas source 110 may be activated to propel the dry reductant into inlet conduit 102.

For example, FIG. 4 is a schematic block diagram of a reductant introduction system 320 that may be used with aftertreatment system 100, according to an embodiment. The reductant introduction system 320 includes a dry reductant tank 322 and a compressed gas source 310 (e.g., a dry air tank or a dry nitrogen tank). The compressed gas source 310 is coupled to a reductant delivery line 330 via a compressed gas line 312, the reductant delivery line 330 being operably coupled to a nozzle 238 positioned within the inlet tube 202. Valve 344 may be coupled to compressed gas source 310 and configured to be selectively opened to selectively deliver compressed gas to reductant delivery line 330.

The dry reductant tank 322 is coupled to a reductant delivery line 330 via a reductant delivery line 321. The dry reductant tank contains a dry reductant 325, e.g., any of the dry reductants described herein. Pressure release valve 316 may be operably coupled to dry reductant tank 322 and configured to open in response to a pressure within dry reductant tank 322 exceeding a predetermined pressure threshold (e.g., increasing the pressure in dry reductant tank as ammonia accumulates in dry reductant tank 322 as it is released from dry reductant 325 over time). Dry reductant tank 322 may be configured to be refilled with dry reductant. In embodiments where the dry reductant is urea, dry reductant tank 322 is filled by simply pouring urea into dry reductant tank 322, for example, via a fill port (not shown). In other embodiments where dry reductant tank 322 includes an ammonia salt, dry reductant tank 322 may be vented (e.g., via an exhaust valve) to remove any ammonia that may have accumulated in dry reductant tank 322 before being refilled with new ammonia salt.

The dry reductant feeder 324 is coupled to the reductant delivery line 321 and is configured to deliver dry reductant from the dry reductant tank 322 to the reductant delivery line 330 via the reductant delivery line 321. Further, dry reductant feeder 324 may be configured to prevent compressed gas from flowing upstream thereof to dry reductant tank 322. For example, in some embodiments, the dry reductant feeder 324 may include a screw feeder or a belt feeder configured to supply a predetermined amount of dry reductant into the reductant delivery line 330 via the reductant delivery line.

In some embodiments where the dry reductant feeder 324 comprises a screw feeder, the dry reductant feeder 324 may be operated at a constant speed or at a desired frequency (e.g., pulse width modulated on-time) to reduce the average dry reductant introduced into the inlet pipe 202 (e.g., to maintain a turndown ratio and/or reduce consumption of dry reductant in diesel SCR applications). In various embodiments, the dry reductant feeder 324 may include multiple augers having the same or different sizes to achieve the proper turndown. In some embodiments, for example, the motor driving the screw feeder may be coupled to, for example, an agitator provided with the dry reductant feeder 324 to reduce caking and facilitate a constant flow of reductant.

In other embodiments, the dry reductant feeder 324 may include a valve configured to selectively allow gravity feeding of dry reductant into the reductant delivery line 330. In such embodiments, when the dry reductant feeder 324 is activated and provides dry reductant to the reductant delivery line 330 (e.g., the valve is open), the compressed gas source 310 may be configured to stop providing compressed gas to the reductant delivery line 330. Once a predetermined amount of dry reductant is delivered into the reductant delivery line 330, the dry reductant feeder 324 is deactivated (e.g., the valve is closed) and the compressed gas source 310 is activated to introduce compressed gas into the reductant delivery line 330 to push dry reductant previously introduced into the reductant delivery line 330 into the inlet conduit 202 via the nozzle 238.

Referring again to FIG. 1A, in some embodiments, the pressurized gas source 110 may include an exhaust gas recirculation line coupled to a first end of the reductant delivery line 130 such that the pressurized gas is a recirculated exhaust gas. For example, FIG. 5 is a schematic block diagram of a reductant introduction system 420, according to another embodiment. The reductant introduction system 420 may be used in the aftertreatment system 100. The reductant introduction system 420 includes a dry reductant tank 322, the dry reductant tank 322 coupled to the reductant delivery line 330 through a dry reductant feeder 324 via a reductant delivery line 321, as previously described herein.

An exhaust gas recirculation line 442 is coupled to the reductant delivery line 330. The exhaust gas recirculation line 442 is configured to receive recirculated exhaust gas, for example, downstream from the SCR system 150, and deliver the recirculated exhaust gas to the reductant delivery line 130. The recirculated exhaust gas may have a temperature sufficient to decompose the dry reductant provided by the dry reductant feeder 324 to produce ammonia gas, which is conveyed into the exhaust gas flow path defined by the inlet conduit 202. In some embodiments, a valve 444 may be coupled to the exhaust gas recirculation line 442 and configured to be selectively opened to deliver recirculated exhaust gas to the reductant delivery line 330.

In some embodiments, the heater 440 may be coupled to the exhaust gas recirculation line 442 or the reductant delivery line 330. Heater 440 may include a coil heater, a solid state heater, or any other suitable heater configured to heat the recirculated exhaust gas to a temperature sufficient to substantially decompose the dry reductant. In other embodiments, the recirculated exhaust gas may be cooled, for example, by a cooler (not shown) to a temperature below the decomposition temperature of the dry reductant. In such embodiments, the recirculated exhaust gas entrains particles of the dry reductant and propels the dry reductant into an exhaust flow path where the dry reductant decomposes to release ammonia.

Referring again to FIG. 1A, in some embodiments, the reductant introduction system 120 may also include an injector coupled to the reductant delivery line downstream of the reductant delivery line 130. The pressurized gas source 110 may be coupled to the reductant delivery line 130 via an injector. An injector (e.g., a vacuum pump) is configured to create a suction force in reductant delivery line 130 to deliver dry reductant to SCR system 150 via reductant delivery line 130.

For example, FIG. 6 is a schematic block diagram of a reductant introduction system 520, according to another embodiment. The reductant introduction system 520 includes a dry reductant tank 322 containing a dry reductant, a pressurized gas source 310, and a dry reductant feeder 324 coupled to a reductant delivery line 330 via a reductant delivery line 321, as described with respect to the reductant introduction system 320. Unlike the reductant introduction system 320, the injector 540 is coupled to the reductant delivery line 330 downstream of the reductant delivery line 321. The injector 540 may include a vacuum pump or an injection pump configured to create a suction force in the reductant delivery line 330 to draw dry reductant delivered by the dry reductant feeder 324 into the reductant delivery line 330.

A pressurized gas source 310 (e.g., a pressurized air or nitrogen tank) is coupled to the injector 540 via a gas line 514 and, thus, to the reductant delivery line 330. The pressurized gas source 310 may be configured to propel dry reductant drawn into the injector 540 through the injector 540 and the reductant delivery line 330 into the inlet tube 202.

In some embodiments, a first end of the reductant delivery line 330 upstream of the reductant delivery line 321 may be open to atmosphere. For example, the atmospheric line 542 may be coupled to a first end of the reductant delivery line 330. The upstream end of the atmosphere line 542 is open to the atmosphere. When the ejector 540 generates a suction force, the ejector 540 sucks atmospheric air through the atmospheric line 542. This may facilitate the creation of a vacuum, and the incoming atmospheric air may facilitate the delivery of dry reductant from reductant delivery line 321 to injector 540. In various embodiments, a filter 544 may be disposed at an inlet of the atmospheric line 542 and configured to remove particulate matter (e.g., dust, debris, organic/inorganic particles, etc.) from atmospheric air drawn into the atmospheric line 542.

Referring again to FIG. 1A, the aftertreatment system 100 also includes a controller 170. Controller 170 may be communicatively coupled to pressurized gas source 110 and dry reductant tank 122, e.g., to valve 124 coupled with reductant delivery line 130 or dry reductant tank 122. The controller 170 may also be coupled to the first sensor 103, the second sensor 105, and/or the engine 10, and configured to receive one or more operating condition signals therefrom to determine an operating condition of the exhaust gas (e.g., an amount of NOx gas in the exhaust gas, an exhaust gas temperature, an exhaust gas pressure, an exhaust gas flow, etc.). For example, the controller 170 may receive signals from the engine 10 (e.g., an engine speed signal, an engine torque signal, an air-fuel ratio signal, etc.), signals from the first sensor 103 and/or the second sensor 105 (e.g., a NOx signal, a temperature signal, a pressure signal, a flow signal, etc.), etc. to determine the operating condition of the exhaust. The controller 170 is also configured to control the amount of dry reductant introduced into the intake conduit 202 and thereby into the SCR system 150 from the intake conduit. For example, the controller 170 may be configured to activate the pressurized gas source 110 and/or open the valve 124 (e.g., valve 234) to introduce dry reductant or ammonia released from decomposed dry reductant (e.g., described with respect to fig. 5) into the inlet conduit 102.

The controller 170 may be operably coupled to the first sensor 103, the second sensor 105, the engine 10, the source of pressurized gas 110, and/or the valve 124 using any type and any number of wired or wireless connections. For example, the wired connection may include a serial cable, a fiber optic cable, a CAT5 cable, or any other form of wired connection. The wireless connection may include the Internet, Wi-Fi, cellular network, radio, Bluetooth, ZigBee, etc. In one embodiment, a Controller Area Network (CAN) bus provides for the exchange of signals, information, and/or data. The CAN bus includes any number of wired and wireless connections.

In certain embodiments, the controller 170 may be included in the control circuitry. For example, fig. 2 is a schematic block diagram of a control circuit 171 including a controller 170 according to an embodiment. Controller 170 includes a processor 172, a memory 174 or any other computer-readable medium, and a communication interface 176. In addition, the controller 170 includes an operating condition determination circuit 174a and a dry reductant feed control circuit 174 b. It should be understood that the controller 170 illustrates only one embodiment of the controller 170, and any other controller capable of performing the operations described herein may be used.

Processor 172 may include a microprocessor, a Programmable Logic Controller (PLC) chip, an ASIC chip, or any other suitable processor. The processor 172 is in communication with the memory 174 and is configured to execute instructions, algorithms, commands, or other programs stored in the memory 174.

Memory 174 includes any of the memories and/or storage components discussed herein. For example, memory 174 may include RAM and/or cache memory for processor 172. The memory 174 may also include one or more storage devices (e.g., hard disk drives, flash drives, computer-readable media, etc.) local or remote to the controller 170. The memory 174 is configured to store a look-up table, algorithm, or instructions.

In one configuration, the operating condition determination circuit 174a and the dry reductant feed control circuit 174b are embodied as a machine or computer readable medium (e.g., stored in the memory 174) that is executable by a processor, such as the processor 172. As described herein, and in other uses, a machine-readable medium (e.g., memory 174) facilitates performing certain operations to enable receiving and transmitting data. For example, a machine-readable medium may provide instructions (e.g., commands, etc.) to, for example, retrieve data. In this regard, the machine-readable medium may include programmable logic that defines the acquisition (or transmission) frequency of data. Thus, the computer-readable medium may include code that may be written in any programming language, including but not limited to Java and the like, and any conventional procedural programming languages, such as the "C" programming language or similar programming languages. The computer readable program code may be executed on one processor or on multiple remote processors. In the latter case, the remote processors may be connected to each other through any type of network (e.g., CAN bus, etc.).

In another configuration, the operating condition determination circuit 174a and the dry reductant feed control circuit 174b are embodied as hardware units, such as electronic control units. As such, the operating condition determination circuit 174a and the dry reductant feed control circuit 174b may be embodied as one or more circuit components including, but not limited to, processing circuitry, network interfaces, peripheral devices, input devices, output devices, sensors, and the like.

In some embodiments, the operating condition determining circuit 174a and the dry reductant feed control circuit 174b may take the form of one or more analog circuits, electronic circuits (e.g., Integrated Circuits (ICs), discrete circuits, system-on-a-chip (SOC) circuits, microcontrollers, etc.), telecommunications circuits, hybrid circuits, and any other type of "circuit. In this regard, the operating condition determination circuit 174a and the dry reductant feed control circuit 174b may include any type of components to accomplish or facilitate the operations described herein. For example, the circuits described herein may include one OR more transistors, logic gates (e.g., NAND, AND, NOR, OR, XOR, NOT, XNOR, etc.), resistors, multiplexers, registers, capacitors, inductors, diodes, wiring, AND the like.

Accordingly, the operating condition determination circuit 174a and the dry reductant feed control circuit 174b may also include programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices, or the like. In this regard, the operating condition determination circuit 174a and the dry reductant feed control circuit 174b may include one or more memory devices for storing instructions executable by one or more processors of the operating condition determination circuit 174a and the dry reductant feed control circuit 174 b. The one or more storage devices and the one or more processors may have the same limitations as provided below with respect to the memory 174 and the processor 172.

In the illustrated example, the controller 170 includes a processor 172 and a memory 174. The processor 172 and the memory 174 may be constructed or configured to execute or implement the instructions, commands, and/or control processes described herein with respect to the operating condition determination circuit 174a and the dry reductant feed control circuit 174 b. Thus, the depicted configuration represents the foregoing arrangement, wherein the operating condition determining circuit 174a and the dry reductant feed control circuit 174b are embodied as a machine or computer readable medium. However, as noted above, this illustration is not meant to be limiting as the present disclosure contemplates other embodiments, such as the aforementioned embodiments in which at least one of the operating condition determining circuit 174a and the dry reductant feed control circuit 174b, or the operating condition determining circuit 174a and the dry reductant feed control circuit 174b, is configured as a hardware unit. All such combinations and variations are intended to fall within the scope of the present disclosure.

Processor 172 may be implemented as one or more general processors, Application Specific Integrated Circuits (ASICs), one or more Field Programmable Gate Arrays (FPGAs), Digital Signal Processors (DSPs), a set of processing elements, or other suitable electronic processing elements. In some embodiments, one or more processors may be shared by multiple circuits (e.g., operating condition determination circuit 174a and dry reductant feed control circuit 174b) may include or otherwise share the same processor, which in certain exemplary embodiments may execute instructions stored or otherwise accessed via different memory regions). Alternatively or additionally, one or more processors may be configured to perform certain operations independently of or otherwise perform operations by one or more coprocessors. In other exemplary embodiments, two or more processors may be coupled via a bus to enable independent, parallel, pipelined, or multithreaded instruction execution. All such variations are intended to fall within the scope of the present disclosure. Memory 174 (e.g., RAM, ROM, flash memory, hard disk memory, etc.) may store data and/or computer code to facilitate the various processes described herein. Memory 174 may be communicatively connected to processor 172 to provide computer code or instructions to processor 172 to perform at least some of the processes described herein. Further, the memory 174 may alternatively comprise a tangible non-transitory volatile or non-volatile memory. Thus, memory 174 may include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described herein.

Communication interface 176 may include a wireless interface (e.g., jack, antenna, transmitter, receiver, communication interface, wired terminal, etc.) for data communication with various systems, devices, or networks. For example, communication interface 176 may include an ethernet card and ports for sending and receiving data via an ethernet-based communication network and/or a Wi-Fi communication interface for communicating with engine 10, first sensor 103, second sensor 105, dry reductant tank 122 (or dry reductant feeder 324 in other embodiments), valve 124 (or valves 234, 344, 444 in other embodiments), and/or pressurized gas source 110 or other controller (e.g., an engine control unit). Communication interface 176 may be configured to communicate via a local or wide area network (e.g., the internet, etc.) and may use various communication protocols (e.g., IP, LON, bluetooth, ZigBee, radio, cellular networks, near field communication, etc.).

The operating condition determining circuit 174a is configured to receive the operating condition signals (e.g., signals from the engine 10, the first sensor 103, and/or the second sensor 105) and determine the operating condition of the exhaust gas, as previously described herein. The dry reductant feed control circuit 174b is configured to generate a reductant introduction signal based on an operating condition of the exhaust gas. For example, the reductant introduction signal may be configured to open the valve 124, 234 for a predetermined time to allow a predetermined volume of dry reductant to be introduced into the reductant delivery line 130, 230. In other embodiments, the reductant introduction signal may be configured to selectively activate the dry reductant feeder 324 to introduce a predetermined amount of dry reductant into the reductant delivery line 330. Further, the reductant introduction signal may also be configured to activate the compressed gas source 310 or open valve 344 to allow compressed gas to be delivered to the reductant delivery line 330, or open valve 444 to allow recirculated exhaust gas to be delivered to the reductant delivery line 330. The compressed gas pushes the dry reductant into the exhaust flow path or the recirculated exhaust gas may decompose the dry reductant to produce ammonia that is delivered into the exhaust flow path.

FIG. 7 shows a plot of particle size versus decomposition time for urea particles introduced into the exhaust flow path. For urea particles in the size range of 30-20 microns, the fastest decomposition time of less than about 0.01 seconds is observed. The lowest decomposition temperature of the urea granules was observed to be 135 degrees celsius. Although the decomposition energy of liquid Diesel Exhaust Fluid (DEF) is about 2,735kJ/kg, urea pyrolysis occurs at about 1,082kJ/kg, which reduces the decomposition energy by about 60%. Regardless of the particle size, ammonia is generated almost instantaneously in the case of solid particles. However, depending on the particle size and the particular dry reductant used, complete decomposition of all particles to deliver a complete ammonia dose may take a longer time. In the case of decomposition of the ammonium salt at a temperature of about 60 degrees celsius, the decomposition time may be even faster. Lower decomposition temperatures result in faster decomposition, which can result in a significant increase in particle size.

Fig. 8 shows a plot of decomposition time versus particle size of dry urea particles versus droplet size of DEF. The smaller urea particles contain about the same mass of ammonia relative to larger sized DEF droplets that decompose in the same decomposition time. Thus, the tank for dry reductant can be made much smaller than the DEF tank and still contain the same ammonia mass, thus making the structure compact.

FIG. 9 is a schematic flow diagram of an exemplary method 600 for introducing dry reductant into an aftertreatment system (e.g., aftertreatment system 100) including a dry reductant tank (e.g., dry reductant tank 122, 222, 322) and a pressurized gas source (e.g., pressurized gas source 110, 210, 310) using a reductant introduction system (e.g., reductant introduction system 120, 220, 320, 420, 520). Method 600 includes determining an operating condition of the exhaust at 602. For example, the operating condition determining circuit 174a may receive the operating condition signals (e.g., from the engine 10, the first sensor 103, and/or the second sensor 105) and determine the operating condition of the exhaust gas, as previously described herein.

At 604, the reductant introduction system is activated based on the operating conditions of the exhaust. For example, the dry reductant feed control circuit 174b may generate the reductant introduction signal based on the operating conditions of the exhaust. For example, the reductant introduction signal may be configured to open the valve 124, 234 for a predetermined time to allow a predetermined volume of dry reductant to be introduced into the reductant delivery line 130, 230. In other embodiments, the reductant introduction signal may be configured to selectively activate the dry reductant feeder 324 to introduce a predetermined amount of dry reductant into the reductant delivery line 330. Further, the reductant introduction signal may also be configured to activate the compressed gas source 310 or open valve 344 to allow compressed gas to be delivered to the reductant delivery line 330, or open valve 444 to allow recirculated exhaust gas to be delivered to the reductant delivery line 330. In still other embodiments, the reductant introduction signal may be configured to also activate the injector 540 to draw reductant into the reductant delivery line 330 that is delivered to the pressurized air driven inlet tube 202 delivered by the compressed gas source 310, as previously described herein.

FIG. 10 is a schematic flow chart of another method 700 for using a dry reductant system in an aftertreatment system (e.g., aftertreatment system 100) that uses a dry reductant introduction system (e.g., reductant introduction system 120, 420, 520) that includes a dry reductant tank (e.g., dry reductant tank 122, 222, 322) and a pressurized gas source (e.g., pressurized gas source 110, 210, 310 or exhaust gas recirculation line 442). Method 700 includes determining an operating condition of the exhaust at 702. For example, the operating condition determining circuit 174a may receive the operating condition signals (e.g., signals from the engine 10, the first sensor 103, and/or the second sensor 105) and determine the operating condition of the exhaust gas, as previously described herein.

At 704, pressurized gas is provided to the reductant delivery line. For example, in some embodiments, the pressurized gas source 110 or the compressed gas source 310 may be activated (e.g., by opening the valve 324) to provide pressurized gas (e.g., compressed dry air or nitrogen) to the reductant delivery line 130, 330. In a particular embodiment, the pressurized gas source may include an exhaust gas recirculation line 442, and the pressurized gas may include recirculated exhaust gas. In such embodiments, recirculated exhaust gas is provided to the reductant delivery line 330, for example, by opening valve 444.

In some embodiments, at 706, it is determined whether the temperature of the pressurized gas (e.g., recirculated exhaust gas) is greater than a predetermined temperature threshold. If the temperature is greater than the predetermined temperature threshold (706: Yes), the method proceeds to operation 710 and a dry reductant feeder (e.g., dry reductant feeder 324) is activated to deliver dry reductant to a reductant delivery line (e.g., reductant delivery line 330). In response to the temperature being less than the predetermined temperature threshold (706: no), the pressurized gas is heated (e.g., via heater 440), such as at 708, to increase the temperature of the pressurized gas (e.g., recirculated exhaust gas) to a temperature sufficient to decompose the dry reductant. Method 700 then proceeds to operation 710, as previously described herein.

It should be noted that the term "example" as used herein to describe various embodiments is intended to indicate that such embodiments are possible examples, representations, and/or illustrations of possible embodiments (and this term is not intended to indicate that such embodiments are necessarily extraordinary or best-shown examples).

The term "coupled" or the like as used herein means that two members are directly or indirectly joined to each other. Such engagement may be fixed (e.g., permanent) or movable (e.g., removable or releasable). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another.

As used herein, the term "about" generally refers to plus or minus 10% of the stated value. For example, about 0.5 would include 0.45 and 0.55, about 10 would include 9 to 11, and about 1000 would include 900 to 1100.

It is important to note that the construction and arrangement of the various exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited herein. Additionally, it should be understood that features of one embodiment disclosed herein may be combined with features of other embodiments disclosed herein, as would be understood by one of ordinary skill in the art. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present inventions.

While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any invention or of what may be claimed, but rather as descriptions of features specific to particular implementations of particular inventions. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. In addition, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.