Valve arrangement for split close-coupled catalyst

Abstract

The present application relates to valve arrangements for split close-coupled catalysts. An aftertreatment system includes a first exhaust path, a second exhaust path, and a selector valve configured to divert exhaust gas between the first exhaust path and the second exhaust path based on a temperature of the exhaust gas. The aftertreatment system also includes a controller programmed to control the selector valve such that the selector valve diverts at least a portion of the exhaust gas to the first exhaust path when the temperature of the exhaust gas is equal to or less than a predetermined temperature threshold, and the selector valve diverts the exhaust gas to the second exhaust path when the temperature of the exhaust gas is greater than the predetermined temperature threshold. The first exhaust path includes a heater configured to heat the exhaust gas received in the first exhaust path.

Description

[0001] This application is a divisional application of the application filed on May 9, 2019, with application number 201980096116.0 and invention title "Valve device for split-flow tightly coupled catalyst". Technical Field

[0002] This disclosure relates to aftertreatment systems commonly used with internal combustion engines. background

[0003] Exhaust aftertreatment systems are used to treat exhaust gases produced by internal combustion engines. These systems typically include a selective catalytic reduction (SCR) system, which is formulated to reduce nitrogen oxides in the exhaust gases in the presence of a catalyst and a reducing agent. Exhaust aftertreatment systems may also include one or more filters to remove debris and other particles from the exhaust gases. By treating exhaust gases using an exhaust aftertreatment system, the system reduces the level of harmful emissions that would otherwise be released into the atmosphere. However, current exhaust aftertreatment systems have limitations due to their construction and operation. Invention Overview

[0004] 1) According to some aspects of this disclosure, an aftertreatment system is disclosed. The aftertreatment system includes a first exhaust path, a second exhaust path, and a selector valve configured to divert exhaust gas between the first and second exhaust paths based on the temperature of the exhaust gas. The aftertreatment system also includes a controller programmed to control the selector valve such that when the exhaust gas temperature is equal to or less than a predetermined temperature threshold, the selector valve diverts at least a portion of the exhaust gas to the first exhaust path, and when the exhaust gas temperature is greater than the predetermined temperature threshold, the selector valve diverts the exhaust gas to the second exhaust path. The first exhaust path includes a heater configured to heat the exhaust gas received in the first exhaust path.

[0005] 2) According to the aftertreatment system of 1), wherein the first exhaust path further includes a first decomposition chamber configured to receive (i) a reducing agent and (ii) exhaust gas that has been diverted to the first exhaust path by the selector valve and heated by the heater.

[0006] 3) The aftertreatment system according to 2), wherein the second exhaust path includes a second decomposition chamber configured to receive (i) a reducing agent and (ii) exhaust gas that has been diverted to the second exhaust path by the selector valve.

[0007] 4) The post-processing system according to 3) further includes:

[0008] A combined exhaust path is located downstream of the first and second decomposition chambers.

[0009] The combined exhaust path is configured to receive (i) reducing agent and heated exhaust from the first decomposition chamber, and / or receive (ii) reducing agent and exhaust from the second decomposition chamber.

[0010] 5) The aftertreatment system according to 4), wherein the combined exhaust path includes a selective catalytic reduction catalyst.

[0011] 6) According to the aftertreatment system of 5), wherein the combined exhaust path further includes an ammonia escape catalyst located downstream of the selective catalytic reduction catalyst.

[0012] 7) The post-processing system according to any one of 2)-6) further includes a reducing agent evaporator configured to inject evaporated reducing agent into the first decomposition chamber.

[0013] 8) The post-processing system according to 2), wherein:

[0014] The first exhaust path further includes a first selective catalytic reduction catalyst, which is located downstream of the first decomposition chamber.

[0015] The first selective catalytic reduction catalyst is configured to receive (i) a reducing agent and (ii) heated exhaust gas from the first decomposition chamber.

[0016] 9) The post-processing system according to 8), wherein the first selective catalytic reduction catalyst comprises a copper-based catalyst, an iron-based catalyst, or a vanadium-based catalyst.

[0017] 10) The aftertreatment system according to 8) or 9), wherein the first exhaust path further includes an ammonia escape catalyst located downstream of the first selective catalytic reduction catalyst.

[0018] 11) The aftertreatment system according to 8), wherein the second exhaust path includes a second decomposition chamber configured to receive (i) a reducing agent and (ii) exhaust gas that has been diverted to the second exhaust path by the selector valve.

[0019] 12) The post-processing system according to 11), wherein:

[0020] The second exhaust path also includes a second selective catalytic reduction catalyst, which is located downstream of the second decomposition chamber.

[0021] The second selective catalytic reduction catalyst is configured to receive (i) a reducing agent and (ii) exhaust gas from the second decomposition chamber.

[0022] 13) The aftertreatment system according to 12), wherein the second exhaust path further includes an ammonia escape catalyst located downstream of the second selective catalytic reduction catalyst.

[0023] 14) The post-processing system according to 12) further includes a liquid reducing agent metering feeder configured to inject liquid reducing agent into the second decomposition chamber.

[0024] 15) The post-processing system according to 12), wherein:

[0025] The first exhaust path includes a first ammonia escape catalyst, which is located downstream of the first selective catalytic reduction catalyst.

[0026] The second exhaust path includes a second ammonia escape catalyst, which is located downstream of the second selective catalytic reduction catalyst.

[0027] 16) The aftertreatment system according to any one of 12)-15), wherein the size of the first selective catalytic reduction catalyst in the first exhaust path is smaller than the size of the second selective catalytic reduction catalyst in the second exhaust path.

[0028] 17) The post-treatment system according to any one of 12)-15), wherein at least one of the first selective catalytic reduction catalyst or the second selective catalytic reduction catalyst is a selective catalytic reduction filter.

[0029] 18) The post-processing system according to any one of 11)-13) and 15) further comprises:

[0030] A reducing agent evaporator, configured to inject evaporated reducing agent into the first decomposition chamber; and

[0031] A liquid reducing agent metering feeder is configured to inject liquid reducing agent into the second decomposition chamber.

[0032] 19) The post-processing system according to 8) further includes:

[0033] A combined exhaust path, wherein the combined exhaust path is located downstream of the first selective catalytic reduction catalyst and the second exhaust path.

[0034] The combined exhaust path is configured to receive exhaust from the first selective catalytic reduction catalyst and the second exhaust path.

[0035] 20) The after-treatment system according to 19) further includes a second decomposition chamber located downstream of the combined exhaust path.

[0036] 21) The aftertreatment system according to 20) further includes an oxidation catalyst located downstream of the combined exhaust path and upstream of the second decomposition chamber.

[0037] 22) The post-treatment system according to 21) further includes a particulate filter located downstream of the oxidation catalyst and upstream of the second decomposition chamber.

[0038] 23) The post-treatment system according to any one of 20)-22) further includes a second selective catalytic reduction catalyst, the second selective catalytic reduction catalyst being located downstream of the second decomposition chamber.

[0039] 24) The post-treatment system according to 23) further includes an ammonia escape catalyst, which is located downstream of the second selective catalytic reduction catalyst.

[0040] 25) The post-processing system according to any one of 1)-6), 8)-9), 11)-15), 19)-22) and 24), wherein the predetermined temperature threshold is in the range of 70°C to 180°C.

[0041] 26) The aftertreatment system according to 1), wherein the controller is programmed to control the selector valve such that when the temperature of the exhaust gas is equal to or less than the predetermined temperature threshold, the selector valve diverts all exhaust gas to the first exhaust path.

[0042] 27) According to the aftertreatment system of 1), wherein the second exhaust path includes a first decomposition chamber configured to receive (i) a reducing agent and (ii) exhaust gas that has been diverted to the second exhaust path by the selector valve.

[0043] 28) The post-treatment system according to 27) further includes a first selective catalytic reduction catalyst located downstream of the first decomposition chamber.

[0044] 29) The post-processing system according to 28) further includes:

[0045] The combined exhaust path is located downstream of the first selective catalytic reduction catalyst and the first exhaust path.

[0046] The combined exhaust path is configured to receive exhaust from the first selective catalytic reduction catalyst and the first exhaust path.

[0047] 30) The aftertreatment system according to 29), wherein the combined exhaust path includes a second decomposition chamber.

[0048] 31) The aftertreatment system according to 30), wherein the combined exhaust path further includes an oxidation catalyst located upstream of the second decomposition chamber.

[0049] 32) The aftertreatment system according to 31), wherein the combined exhaust path further includes a particulate filter located downstream of the oxidation catalyst and upstream of the second decomposition chamber.

[0050] 33) The aftertreatment system according to any one of 30)-32), wherein the combined exhaust path further includes a second selective catalytic reduction catalyst located downstream of the second decomposition chamber.

[0051] 34) According to the aftertreatment system of 33), wherein the combined exhaust path further includes an ammonia escape catalyst located downstream of the second selective catalytic reduction catalyst.

[0052] 35) An aftertreatment system according to any one of 1)-6), 8)-9), 11)-15), 19)-22), 24), 26)-32), and 34), wherein the controller is further configured to control the selector valve based on the ratio of ammonia to NOx in the exhaust gas.

[0053] 36) According to some other aspects of this disclosure, a method is disclosed. The method includes determining the temperature of an exhaust gas by a controller associated with an aftertreatment system, comparing the temperature of the exhaust gas with a predetermined temperature threshold by the controller, and adjusting a selector valve to a first position to divert at least a portion of the exhaust gas to a first exhaust path when the temperature of the exhaust gas is equal to or less than the predetermined temperature threshold, heating the exhaust gas in the first exhaust path, and adjusting the selector valve to a second position to divert at least a portion of the exhaust gas to a second exhaust path when the temperature of the exhaust gas is greater than the predetermined temperature threshold.

[0054] It should be recognized that all combinations of the foregoing concepts and the additional concepts discussed in more detail below (provided these concepts are not contradictory) are contemplated as part of the subject matter disclosed herein. In particular, all combinations of the claimed subject matter appearing at the end of this disclosure are contemplated as part of the subject matter disclosed herein. Brief description of the attached diagram

[0055] The foregoing and other features of this disclosure will become more apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. It should be understood that these drawings depict only a few embodiments according to this disclosure and are therefore not intended to limit its scope; the disclosure will be described using additional features and details through the use of the drawings.

[0056] Figure 1 This is an example block diagram of a post-processing system according to some embodiments of the present disclosure.

[0057] Figure 2 This is another example block diagram of a post-processing system according to some embodiments of the present disclosure, illustrating a tightly coupled system in which exhaust gas is diverted to a first exhaust path or a second exhaust path.

[0058] Figure 3 This is yet another example block diagram of a post-processing system according to some embodiments of the present disclosure, illustrating another tightly coupled system in which exhaust is diverted to a first exhaust path or a second exhaust path.

[0059] Figure 4A and Figure 4B This is an example block diagram of a post-processing system according to some embodiments of the present disclosure, illustrating a tightly coupled system in which exhaust gas enters a combined exhaust path from a first exhaust path or a second exhaust path.

[0060] Figure 5 This is an overview of some embodiments based on the present disclosure for operation. Figures 2-4B Example flowchart of the operation of the post-processing system.

[0061] Reference is made to the accompanying drawings in the detailed description below. In the drawings, similar symbols generally identify similar components unless the context otherwise requires. 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 herein. It will be readily understood that, as generally described herein and shown in the drawings, aspects of this disclosure can be arranged, substituted, combined, and designed in a variety of different configurations, all of which are expressly contemplated and are part of this disclosure. Detailed description

[0062] This application relates to an aftertreatment system designed for treating exhaust gas from engines. The aftertreatment system can remove various types of unwanted components from the exhaust gas before releasing the treated exhaust gas into the atmosphere. The aftertreatment system may include a decomposition chamber that receives a reducing agent converted into gaseous ammonia and mixed with the exhaust gas. The mixture of exhaust gas and gaseous ammonia is then directed to a selective catalytic reduction (“SCR”) system, in which the gaseous ammonia is catalyzed to reduce NOx in the exhaust gas.

[0063] The decomposition chamber and SCR system are configured to operate optimally at specific temperatures (e.g., above 180°C). At lower temperatures, such as those encountered during cold start conditions, the reductant injected into the decomposition chamber is more likely to form solid deposits on the chamber walls. The reductant deposited on the chamber walls does not convert to gaseous ammonia and does not mix with the exhaust gas. If there is insufficient gaseous ammonia in the mixture, the reaction in the SCR system will be affected, and the desired NOx reduction level cannot be achieved. Therefore, it may be necessary to increase the amount of reductant to achieve the desired NOx reduction level at lower temperatures. Furthermore, at lower temperatures, even if the decomposition chamber operates effectively, the SCR system may fail to achieve its desired NOx reduction level, resulting in greater NOx emissions into the atmosphere and potentially violating certain emission regulations.

[0064] Furthermore, SCR systems use SCR catalysts that need to adsorb a sufficient amount of gaseous ammonia before reducing NOx in the exhaust gas. At certain temperatures (e.g., close to 300°C), the adsorbed ammonia may be desorbed and released into the environment. Therefore, it is undesirable for the SCR system to always be filled with ammonia. However, at low temperatures, waiting for sufficient ammonia to adsorb into the SCR catalyst when the SCR system is already operating at lower efficiency will further degrade performance. Thus, low temperatures present challenges, such as the formation of solid deposits on the walls of the decomposition chamber and the difficulty in converting NOx by the SCR system.

[0065] To improve the efficiency of the decomposition chamber and SCR system at low temperatures, the reducing agent can be introduced into the decomposition chamber in evaporative form to reduce the formation of solid deposits on the chamber walls. While evaporators are beneficial at low temperatures, they are not necessarily needed during normal engine operation. In some cases, specialized SCR catalysts optimized for low-temperature operating conditions can be used in the SCR system. However, the optimized SCR catalyst itself may not be sufficient to achieve the desired NOx reduction levels. Keeping the SCR system constantly filled with ammonia is also impractical, as ammonia readily desorbs under ambient operating conditions.

[0066] Therefore, this disclosure provides a technical solution for improving the operational efficiency of the decomposition chamber and / or SCR system. The aftertreatment system of this disclosure provides a dual-path system, wherein exhaust gas leaving the engine can take a first exhaust path if the exhaust temperature is equal to or less than a predetermined temperature threshold, and exhaust gas leaving the engine can take a second exhaust path if the temperature of the exhaust path is greater than the predetermined temperature threshold. Therefore, in some embodiments, exhaust gas can be directed to the first exhaust path during low temperatures and to the second exhaust path during normal temperatures. A selector valve can be used to divert exhaust gas between the first and second exhaust paths. The first exhaust path can be optimized for low-temperature operation.

[0067] For example, in some embodiments, a heater may be used to heat at least a portion of the gas diverted to the first exhaust path. The heater may be activated for a period of time until the exhaust temperature reaches a desired target temperature. In some embodiments, the controller may selectively and dynamically activate and deactivate the heater using feedback inputs based on the current and desired temperatures within the decomposition chamber and / or the SCR system. In some embodiments, all exhaust gas may be heated during cryogenic conditions, while in other embodiments, only a portion of the exhaust gas may be heated during cryogenic conditions. Heating even a portion of the exhaust gas during cryogenic conditions can improve the efficiency of the decomposition chamber and / or the SCR system.

[0068] Furthermore, in some embodiments, an evaporator can be used in the first exhaust path to further improve the efficiency of the decomposition chamber. In some embodiments, the SCR system can use an SCR catalyst optimized for cryogenic operation. Because ammonia is not easily desorbed at low temperatures, in some embodiments, the SCR system can always be filled with ammonia.

[0069] Therefore, this disclosure provides an effective mechanism for improving the efficiency of an aftertreatment system during engine low-temperature operating conditions.

[0070] Now for reference Figure 1 According to some embodiments of this disclosure, an example block diagram of an aftertreatment system 100 is shown. The aftertreatment system 100 is configured to receive exhaust gas from an engine 105. The engine 105 may be a compression-ignition internal combustion engine (e.g., a diesel engine), a spark-ignition internal combustion engine (e.g., a gasoline engine), or any other type of engine (e.g., a natural gas engine, a dual-fuel engine, a biodiesel engine, an E-85 engine, etc.). The engine 105 emits exhaust gas as air from the atmosphere burns with fuel. The exhaust gas is discharged from the engine 105 into a housing 115 via an inlet pipe 110.

[0071] Housing 115 defines an internal volume within which one or more components for handling exhaust gases are disposed. To withstand operating conditions, housing 115 may be formed of a rigid, heat-resistant, and corrosion-resistant material, such as stainless steel, iron, aluminum, metal, ceramic, or any other suitable material. Although housing 115... Figure 1 The housing is shown as having a specific shape and size, but the housing can have any suitable cross-section (e.g., circular, square, rectangular, oval, elliptical, polygonal, etc.) and any suitable size. The housing 115 can contain an oxidation catalyst 120 for oxidizing nitrogen monoxide and certain types of particulate matter from the exhaust gas, and for decomposing unburned hydrocarbons from the exhaust gas. In some embodiments, the oxidation catalyst 120 can be a diesel oxidation catalyst (“DOC”) or other type of oxidation catalyst suitable for the aftertreatment system 100.

[0072] In some embodiments, the aftertreatment system 100 may include a hydrocarbon insertion assembly 125 for selectively injecting hydrocarbons (e.g., fuel) into an oxidation catalyst 120. The oxidation catalyst 120 can catalyze the ignition of hydrocarbons, thereby increasing the temperature of the exhaust gas used to regenerate the oxidation catalyst. In some embodiments, the aftertreatment system 100 may also include a particulate filter within a housing 115. Figure 1 (Not shown in the diagram). A particulate filter can be positioned downstream or upstream of the oxidation catalyst 120. When positioned "upstream" of the oxidation catalyst 120, the particulate filter can be located between the inlet pipe 110 and the oxidation catalyst, allowing exhaust gas exiting the particulate filter to enter the oxidation catalyst. When positioned "downstream" of the oxidation catalyst 120, the particulate filter can be located between the oxidation catalyst and the selective catalytic reduction ("SCR") system 130, allowing exhaust gas exiting the oxidation catalyst to enter the particulate filter. In some embodiments, the particulate filter can be positioned both upstream and downstream of the oxidation catalyst 120. The particulate filter can be configured to remove particulate matter (e.g., soot, debris, inorganic particles, etc.) from the exhaust gas. The particulate filter can be any of a variety of filters suitable for use within the aftertreatment system 100. For example, in some embodiments, the particulate filter can be a diesel particulate filter ("DPF") with a ceramic filter (e.g., cordierite) and can be symmetrical or asymmetrical. In some embodiments, the particulate filter can be catalytically activated. In some embodiments, the oxidation catalyst 120 and the particulate filter can be integrated into a single component.

[0073] The housing 115 may also include an SCR system 130 configured to reduce components from the exhaust gas, such as nitrogen oxides (NOx), carbon monoxide (CO), hydrocarbons, etc. The SCR system 130 may include or be associated with a decomposition chamber configured to receive reducing agent from a reducing agent reservoir 135 via a reducing agent insertion assembly 140. A reducing agent port 145 may be located on a side wall of the housing 115 to allow the reducing agent to be inserted into the internal volume of the decomposition chamber. In some embodiments, the reducing agent port 145 may include a reducing agent injector configured to combine a stream of reducing agent received via the reducing agent port 145 with compressed air and deliver the reducing agent-air combination stream or jet into the decomposition chamber. In some embodiments, the reducing agent injector may be a nozzle of a predetermined diameter. In other embodiments, other mechanisms may be used to selectively deliver the reducing agent into the decomposition chamber. Thus, the decomposition chamber may be configured to receive exhaust gas and reducing agent and facilitate mixing of the exhaust gas and reducing agent to form an exhaust gas-reducing agent mixture. In some embodiments, a mixer, baffle, blade, or other structure may be used in conjunction with a decomposition chamber to further facilitate the mixing of the reducing agent with the exhaust gas.

[0074] The decomposition chamber can be located in various positions. For example, in some embodiments, the decomposition chamber may be positioned upstream of the SCR system 130 to allow the reducing agent to be inserted into the decomposition chamber upstream of the SCR system via the reducing agent port 145. In other embodiments, the decomposition chamber may be configured such that the reducing agent port 145 is configured to allow the reducing agent to be directly inserted into the SCR system 130. In other embodiments, the decomposition chamber may be located in the inlet conduit 110. Therefore, the positioning of the decomposition chamber can vary from one embodiment to another.

[0075] The reducing agent injected into the decomposition chamber via the reducing agent port 145 can be stored in the reducing agent reservoir 135. The reducing agent promotes the decomposition of exhaust components (e.g., NOx gases included in the exhaust). Depending on the composition of the exhaust, any suitable reducing agent can be used. For example, in some embodiments, the exhaust may include diesel exhaust, and the reducing agent may include a diesel exhaust fluid (e.g., named as...). The reducing agent is a fluid used in the sale of diesel exhaust gas, such as urea, an aqueous urea solution, or any other fluid including ammonia. When an aqueous urea solution is used as a reducing agent, the solution may include a specific ratio of urea to water. For example, in some embodiments, this ratio may be 32.5% urea and 67.5% deionized water by volume, 40% urea and 60% deionized water by volume, or any other suitable ratio of urea to deionized water. The reducing agent from the reducing agent storage tank 135 can be selectively inserted into the decomposition chamber via the reducing agent insertion assembly 140. The reducing agent insertion assembly 140 may include various structures to facilitate receiving the reducing agent from the reducing agent storage tank 135 and supplying it to the reducing agent port 145. For example, the reducing agent insertion assembly 140 may include various pumps, valves, screens, filters, etc., or be associated with various pumps, valves, screens, filters, etc., to control them. This facilitates receiving the reducing agent from the reducing agent storage tank 135 and supplying it to the reducing agent port 145.

[0076] Furthermore, in some embodiments, the reducing agent can be inserted into the decomposition chamber in liquid or gaseous form. In some embodiments, the reducing agent port 145, particularly the reducing agent injector associated with the reducing agent port, can be configured to inject the reducing agent in liquid form. In such embodiments, the reducing agent port 145 can constitute a "wet metering feeder" or a "liquid metering feeder," or be part of a "wet metering feeder" or a "liquid metering feeder." In other embodiments, an evaporator can be associated with the reducing agent port 145, the reducing agent injector, and / or the reducing agent insertion assembly 140 to evaporate the liquid reducing agent or convert the liquid reducing agent into a gaseous form before it is inserted into the insertion housing 115. Whether inserted in liquid or gaseous form, when injected into the decomposition chamber, the reducing agent undergoes evaporation, pyrolysis, and / or hydrolysis to form gaseous ammonia, which is then mixed with exhaust gas to form an exhaust-reducing agent mixture. The exhaust-reducing agent mixture can then flow through the SCR catalyst 150 of the SCR system 130.

[0077] SCR catalyst 150 is formulated to decompose certain components in exhaust gas using gaseous ammonia as a reagent in the presence of an SCR catalyst. Specifically, SCR catalyst 150 catalyzes gaseous ammonia in the exhaust gas, thereby reducing NOx in the exhaust gas during the oxidation reaction. In some embodiments, SCR catalyst 150 may comprise a metal-zeolite catalyst, including but not limited to copper-CHA-zeolite (e.g., copper-SSZ-13 catalyst), but also other zeolite structures, including copper-SAPO-34 catalyst, copper-LTA, copper-AEI, copper-ZSM, copper-β, copper-chamferrocene, or any other suitable catalyst. In other embodiments, SCR catalyst 150 may comprise a vanadium, iron zeolite, or copper / iron zeolite catalyst. In other embodiments, SCR catalyst 150 may comprise a multi-zone catalyst, such as having a first zone comprising a copper zeolite catalyst and a second zone comprising an iron zeolite catalyst, or vice versa. The SCR catalyst 150 can be disposed on a suitable substrate, such as a monolithic core made of ceramic (e.g., cordierite) or metal (e.g., kanthal), which may define, for example, a honeycomb structure. A washcoat can also be used as a carrier material for the SCR catalyst 150. Such a washcoat material may include, for example, alumina, titanium dioxide, silica, any other suitable washcoat material, or a combination thereof. The monolithic core can be securely positioned in a canister to form an SCR system 130 that can be mounted in an aftertreatment system 100. In some embodiments, a heater 155 may be coupled to the SCR system 130 and configured to heat exhaust gas in the SCR system and / or decomposition chamber. In some embodiments, the SCR system 130 may include a selective catalytic reduction filter (SCRF). The treated exhaust gas (e.g., treated to reduce components such as NOx gases, unburned hydrocarbons, etc.) is discharged into the environment via an outlet conduit 160.

[0078] Although the oxidation catalyst 120, particulate filter, decomposition chamber, and SCR system 130 have been described as being housed within a single housing (e.g., housing 115), in some embodiments, one or more of these components may be housed in separate housings and operatively connected together. Furthermore, although a single instance of each of the oxidation catalyst 120, particulate filter, decomposition chamber, and SCR system 130 has been described, in some embodiments, multiple instances of one or more of these elements may be provided within the post-treatment system 100, if appropriate.

[0079] Still referencing Figure 1The aftertreatment system 100 also includes a controller 165 configured to control the operation of various components of the aftertreatment system during exhaust gas treatment. For example, the controller 165 may be operatively connected to the reducing agent insertion assembly 140 to instruct the reducing agent insertion assembly to selectively deliver reducing agent from the reducing agent reservoir 135 to the reducing agent port 145. The controller 165 may also be operatively connected to the reducing agent port 145 to selectively operate the reducing agent port, thereby inserting the reducing agent received from the reducing agent reservoir 135 into the decomposition chamber. In some embodiments, the reducing agent insertion assembly 140 may be configured to control the operation of the reducing agent port 145.

[0080] The controller 165 can also be configured to control the hydrocarbon insertion assembly 125 to selectively insert hydrocarbons into the oxidation catalyst 120 and to control the heater 155 to operate the heater when needed. The controller 165 can also be connected to other components of the post-processing system 100 controlled by the controller. The controller 165 can be operatively coupled to various components of the post-processing system 100 using any type and any number of wired or wireless connections. For example, in some embodiments, wired connections such as serial cables, fiber optic cables, and CAT5 cables can be used to communicatively connect the controller 165 to one or more components of the post-processing system 100. In other embodiments, wireless connections such as the Internet, wireless networks, cellular, radio, Bluetooth, and Wi-Fi can be used. In some embodiments, a combination of wired and wireless connections can be used. Furthermore, in some embodiments, a controller local area network (CAN) bus can provide the exchange of signals, information, and / or data between the controller 165 and various components of the post-processing system 100.

[0081] Controller 165 may include or be associated with one or more processing units. Processing units may include microprocessors, programmable logic controller (PLC) chips, application-specific integrated circuits (ASICs), one or more field-programmable gate arrays (FPGAs), digital signal processors (DSPs), a set of processing units, or other suitable electronic processing units. The processing units of controller 165 may be configured to execute instructions for performing the operations described herein. Processing units may be implemented in hardware, firmware, software, or any combination thereof. "Executing instructions" means that the processing unit can perform the operation required by the instruction. The processing unit may retrieve instructions from memory associated with controller 165 for execution and copy the instructions in executable form to physical memory. In some embodiments, the processing unit may be configured to execute instructions without first copying them to physical memory. Instructions may be written using one or more programming languages, scripting languages, assembly languages, etc. Therefore, controller 165 may be configured via its associated processing units to execute instructions, algorithms, commands, or programs stored in memory associated with the controller.

[0082] Although a single controller (e.g., controller 165) configured to control more than 100 elements of the post-processing system (e.g., reducing agent insertion assembly 140, hydrocarbon insertion assembly 125, heater 155, etc.) is shown, in some embodiments, separate controllers for one or more of these elements may be used. Controller 165 may include or be associated with other hardware, software, and / or firmware components that may be required or considered useful in performing the functions described herein. Controller 165 may be configured to control the reducing agent insertion assembly 140, hydrocarbon insertion assembly 125, heater 155, and any other elements of the post-processing system 100, controlled by the controller based on data received from one or more sensors (e.g., sensors 170, 175, and 180).

[0083] In some embodiments, sensor 170 may be positioned to measure one or more parameters in the exhaust gas flowing through inlet conduit 110. Sensor 170 may include a NOx sensor configured to measure the amount of NOx gas in the exhaust gas flowing into housing 115. In some embodiments, sensor 170 may include a temperature sensor to measure the exhaust gas temperature at the inlet of housing 115. In some embodiments, sensor 170 may include a pressure sensor, oxygen sensor, particulate matter sensor, or any other sensor to measure parameters that controller 165 may need or is considered to be desired when controlling various components of aftertreatment system 100. Furthermore, although a single sensor (e.g., sensor 170) is shown in inlet conduit 110, in some embodiments, multiple sensors located at different locations in the inlet conduit may be used. Additionally, in some embodiments, a single instance of sensor 170 may be configured to measure a single parameter (e.g., temperature, NOx amount, etc.), while in other embodiments, a single instance of sensor may be configured to measure multiple parameters.

[0084] Similarly, sensor 175 may be positioned to measure one or more parameters in the exhaust gas flowing through outlet duct 160, while sensor 180 may be positioned to measure one or more parameters associated with engine 105. Similar to sensor 170, sensor 175 may include a single sensor or multiple sensors and may be configured to measure desired or anticipated parameters, such as the amount of NOx gas emitted into the environment, temperature, pressure, particulate matter, ammonia (e.g., to determine ammonia slip), etc. Likewise, sensor 180 may include a single sensor or multiple sensors and may be configured to measure one or more operating parameters from engine 105.

[0085] Although sensors 170, 175, and 180 are shown positioned at specific locations within the post-processing system 100, the positioning of these sensors can be appropriately varied. Furthermore, additional or fewer sensors can be used at various suitable locations within the post-processing system 100. Sensors 170, 175, and 180 can be physical or virtual sensors. Sensors 170, 175, and 180 can be configured to collect data and transmit that data to controller 165. Based on this data, controller 165 can then control the operation of other components of the post-processing system 100 (e.g., hydrocarbon insertion assembly 125, reducing agent insertion assembly 140, heater 155, etc.).

[0086] Although some components of the after-processing system 100 are Figure 1The posttreatment system is shown and described herein, but may include other or additional elements that may be suitable. For example, in some embodiments, posttreatment system 100 may include an ammonia slip catalyst (“ASC”) or an ammonia oxidation catalyst (“AMOx”) to reduce ammonia slip (through which ammonia not catalyzed by SCR catalyst 150 may be decomposed). In some embodiments, posttreatment system 100 may include a mixer, baffles, a secondary filter (e.g., a split-pass or catalytic filter), or any other components that may be required or considered desirable for proper operation of posttreatment system 100.

[0087] Steering Reference Figure 2 According to some embodiments of this disclosure, example block diagrams of a post-processing system 200 are shown. The post-processing system 200 may include elements similar to those of the post-processing system 100, but... Figure 2 Only some of these components are shown. The aftertreatment system 200 includes an engine 205 that discharges exhaust gas into an inlet duct 210. A temperature sensor 215 is configured to measure the temperature of the exhaust gas flowing through the inlet duct 210. In some embodiments, the temperature sensor 215 may be a thermistor. In other embodiments, the temperature sensor 215 may be another type of temperature measuring device adapted to measure the temperature of the exhaust gas flowing through the inlet duct 210. The exhaust gas from the inlet duct 210 is directed through a DOC 220 for oxidizing hydrocarbons in the exhaust gas and optionally through a diesel particulate filter (“DPF”) 225 located downstream of the DOC for removing some particulate matter from the exhaust gas. The DOC 220 is similar to the oxidation catalyst 120, and the DPF 225 is similar to the particulate filter described above.

[0088] Exhaust gas is directed from DPF 225 to selector valve 230 located downstream of DPF. Selector valve 230 is configured to divert exhaust gas to either a first exhaust path 235 or a second exhaust path 240 based on exhaust gas temperature measured by temperature sensor 215. First exhaust path 235 includes a first injector 245A that injects a first reducing agent into a first decomposition chamber 250A in the first exhaust path. The reducing agent in the first decomposition chamber 250A is converted into gaseous ammonia and mixed with the exhaust gas diverted to first exhaust path 235. The mixture of exhaust gas and gaseous ammonia is diverted to a first SCR 255A located downstream of the first decomposition chamber 250A in first exhaust path 235. In the first SCR 255A, gaseous ammonia is oxidized in the presence of an SCR catalyst to reduce NOx gas in the exhaust gas. The treated exhaust gas is diverted to a first ASC 260A located downstream of the first SCR 255A. The first ASC 260A decomposes any unreacted ammonia in the exhaust gas received from the first SCR 255A. The exhaust gas from the first ASC 260A is then discharged into the atmosphere via outlet pipe 265. The first exhaust path 235 also includes a heater 270 configured to heat the exhaust gas that has been diverted to the first exhaust path. In some embodiments, the heater 270 may be an electric heater.

[0089] Similarly, the second exhaust path 240 includes a second injector 245B for injecting a second reducing agent into the second decomposition chamber 250B to generate gaseous ammonia. Exhaust gas diverted to the second exhaust path 240 flows into the second decomposition chamber 250B and mixes with the gaseous ammonia. The mixture then enters a second SCR 255B located downstream of the second decomposition chamber 250B. In the second SCR 255B, the gaseous ammonia is oxidized in the presence of an SCR catalyst to reduce NOx in the exhaust gas. A second ASC 260B located downstream of the second SCR 255B decomposes any unreacted ammonia in the exhaust gas. The treated exhaust gas is discharged into the environment from the second exhaust path 240 via an outlet pipe 265.

[0090] Therefore, based on the position of selector valve 230, exhaust gas leaving DPF 225 can take one of two closely connected parallel paths, namely, a first exhaust path 235 or a second exhaust path 240. The position of selector valve 230 can be controlled by controller 275 based on exhaust gas temperature measured by temperature sensor 215. Controller 275 is similar to controller 165. In some embodiments, controller 275 can control the position of selector valve 230 based on exhaust gas temperature measured at other locations, such as the outlet of DOC 220 or the outlet of DPF 225.

[0091] In some embodiments, the selector valve 230 may be a multi-position valve. In some embodiments, the selector valve 230 may be in a default closed position, which prevents exhaust gas from being diverted to either the first exhaust path 235 or the second exhaust path 240. Once a command to divert exhaust gas to the first exhaust path 235 is received from the controller 275, the selector valve 230 may move to a first open position, which is configured to divert all exhaust gas to the first exhaust path. Similarly, once a command to divert exhaust gas to the second exhaust path 240 is received from the controller 275, the selector valve 230 may move to a second open position, which is configured to divert all exhaust gas to the second exhaust path. In some embodiments, as further discussed below, the position of the selector valve 230 may be adjustable between a first open position and a second open position, such that a portion of the exhaust gas can flow to both the first exhaust path 235 and the second exhaust path 240. Therefore, the position of the selector valve 230 determines whether exhaust gas is diverted to the first exhaust path 235, the second exhaust path 240, both the first and second exhaust paths, or not diverted to either the first or second exhaust path.

[0092] The first exhaust path 235 can be configured to be used during cold start conditions when the exhaust temperature (e.g., measured by temperature sensor 215) is below a predetermined temperature threshold. For example, in some embodiments, the first exhaust path 235 can be used to process exhaust leaving DPF 225 if the exhaust temperature is between approximately 70°C and 180°C. In some embodiments, the second exhaust path 240 can be used during normal conditions when the exhaust temperature is above 180°C. In other embodiments, the temperature range used to direct exhaust to the first exhaust path 235 or the second exhaust path 240 can vary. Therefore, the controller 275 can receive the temperature of the exhaust flowing through inlet pipe 210 as measured by temperature sensor 215. Based on the exhaust temperature, the controller 275 can adjust the position of selector valve 230 to direct all exhaust to the first exhaust path 235 or the second exhaust path 240. For example, if the predetermined temperature threshold is 180°C, the controller 275 can instruct selector valve 230 to move to a first open position to direct all exhaust to the first exhaust path 235 when the exhaust temperature is equal to or less than 180°C. Similarly, if the exhaust temperature is above 180°C, the controller 275 can instruct the selector valve 230 to move to the second open position to divert all exhaust to the second exhaust path 240.

[0093] Because the first exhaust path 235 is configured for use during cold start conditions, it can be optimized for efficient operation during those conditions. For example, during cold start conditions, a reducing agent injected into the first decomposition chamber 250A in liquid form may more readily deposit on the walls of the first decomposition chamber, reducing its operating efficiency. Therefore, in some embodiments, the first injector 245A may be associated with an evaporator to evaporate the reducing agent prior to injection. Injecting the evaporated reducing agent can reduce the formation of reducing agent deposits on the walls of the first decomposition chamber 250A. Reducing the formation of reducing agent deposits can increase the operating efficiency of the first decomposition chamber 250A. In other embodiments, a commercially available reducing agent delivery and injection system or another mechanism configured to reduce reducing agent deposits in the first decomposition chamber 250A during cold start conditions may be used.

[0094] In some embodiments, instead of using an evaporator or in addition to using an evaporator, heater 270 can be used to heat the exhaust gas that has been diverted to the first exhaust path 235 to increase the temperature of the exhaust gas, which in turn can increase the temperature within the cavity of the first decomposition chamber 250A. Providing sufficient heat to the first decomposition chamber 250A can further help reduce the formation of reducing agent deposits on the walls of the first decomposition chamber 250A. For example, in some embodiments, the heat from heater 270 can reduce the droplet size of the reducing agent (whether in liquid or evaporated form) in the first decomposition chamber 250A, thereby reducing the formation of reducing agent deposits in the first decomposition chamber.

[0095] Heater 270 can be controlled by controller 275. Controller 275 can activate heater 270 based on the temperature of the exhaust gas diverted to the first exhaust path 235 and a desired target temperature in the first decomposition chamber 250A. Controller 275 can be configured to deactivate heater 270 when the target temperature within the first decomposition chamber 250A is reached. A temperature sensor (not shown) can be located within the first decomposition chamber 250A to measure the temperature within the chamber. The amount of time heater 270 is activated can be based on heater capacity and the heat required to reach the desired temperature. For example, in some embodiments, heater 270 can be configured such that a 1 kW heater 270 increases the exhaust temperature at a rate of approximately 5°C per second. In other embodiments, heater 270 can be configured to achieve other heating rates. Therefore, the first exhaust path 235, and particularly the first decomposition chamber 250A of the first exhaust path, can be optimized to reduce reductant deposits by evaporating the reductant using an evaporator before insertion and / or by using heat from heater 270 after insertion to evaporate the reductant (or reduce the droplet size of the reductant). In other embodiments, additional or supplementary mechanisms that can be configured to reduce reducing agent deposits in the first decomposition chamber 250A may be used.

[0096] In some embodiments, the first SCR 255A may also be optimized for operation during cold start conditions. For example, in some embodiments, the type of SCR catalyst used in the first SCR 255A may be more suitable for use during cold start conditions. In some embodiments, the SCR catalyst in the first SCR 255A may be copper-based, vanadium-based, iron-based, or a combination thereof. Furthermore, in some embodiments, the first SCR 255A may be configured to be always filled with ammonia. During normal operating conditions (e.g., when the exhaust temperature is above 180°C), ammonia from the SCR catalyst may be desorbed and lost to the atmosphere. Therefore, continuous ammonia storage in the SCR catalyst during normal operating conditions is undesirable. However, during cold start conditions, ammonia adsorbed into the SCR catalyst is not easily desorbed.

[0097] Therefore, in some embodiments, the SCR catalyst in the first SCR 255A can be continuously filled with ammonia, enabling the first SCR 255A to immediately reduce NOx from the exhaust gas upon receiving a mixture of gaseous ammonia and exhaust gas from the first decomposition chamber 250A, without first waiting for gaseous ammonia to be adsorbed into the SCR catalyst of the first SCR 255A. In embodiments where the first SCR 255A is configured to always be used for high ammonia storage, the amount of reductant injected into the first decomposition chamber 250A can be reduced to account for ammonia storage in the first SCR. Thus, the SCR catalyst in the first SCR 255A can be selected for high NOx reduction and high ammonia storage during cryogenic periods (e.g., during cold start conditions).

[0098] Furthermore, the first SCR 255A can be configured to begin achieving a desired NOx reduction level at a given temperature. A heater 270 can be used to heat the exhaust gas so that the first SCR 255A reaches a given temperature within its cavity. For example, in some embodiments, if the given temperature at which the first SCR 255A begins to achieve the desired NOx reduction level is approximately 150°C, and the temperature of the exhaust gas entering the first exhaust path 235 (and / or at the inlet of the first SCR) is approximately 90°C, the controller 275 can activate the heater 270 until the exhaust gas temperature is at least 150°C, causing the heat from the exhaust gas to heat the cavity of the first SCR 255A. In some embodiments, the SCR catalyst within the first SCR 255A can be a coupled reducing agent catalyst, which can be configured to store NOx substances in the exhaust gas as ammonium nitrate below a specific temperature and release NOx at a controlled rate when the first SCR is heated (e.g., using heater 270) to a specific temperature, thereby achieving optimal NOx reduction efficiency and accelerating the oxidation of soot on various filters under cold start conditions. Therefore, the first exhaust path 235, particularly the first SCR 255A of the first exhaust path, can be optimized to achieve the desired NOx reduction level by using an SCR catalyst optimized for cold start conditions and / or for high ammonia storage and / or by increasing the temperature within the first SCR using heat from heater 270. Thus, the first decomposition chamber 250A and / or the first SCR 255A can be configured to operate optimally under cold start conditions.

[0099] Additionally, controller 275 can be configured to dynamically control the insertion of a reducing agent into the first decomposition chamber 250A based on one or more inputs. For example, in some embodiments, controller 275 can be configured to control the amount of reducing agent inserted into the first decomposition chamber 250A based on the temperature of the exhaust gas entering the first exhaust path 235, the temperature within the chamber of the first SCR 255A, the total ammonia storage within the first SCR, the ambient pressure, the desired NOx reduction efficiency, and / or the NOx flux emitted by the engine (e.g., the amount of NOx in the exhaust gas leaving the outlet pipe 265). In other embodiments, controller 275 can use other or additional inputs (e.g., the exhaust gas temperature in the outlet pipe 265, the exhaust gas temperature at the inlet of the first SCR, the amount of NOx at the inlet of the first SCR, etc.) to dynamically change the amount of reducing agent injected into the first decomposition chamber 250A. To dynamically change the amount of reducing agent injected into the first decomposition chamber 250A, the controller can receive one or more of the above inputs and determine the amount of reducing agent to be inserted into the first decomposition chamber 250A in real time or substantially in real time. After determining the amount of reducing agent, controller 275 can control the first injector 245A to insert the determined amount of reducing agent. Although not shown, the first exhaust path 235 may include a sensor mounted in a suitable location for providing data to controller 275, based on which the controller can dynamically adjust the reducing agent injected into the first decomposition chamber 250A.

[0100] The controller 275 can also use data from one or more such sensors to control the operation of the heater 270. For example, the controller 275 can determine the temperature inside the first decomposition chamber 250A and / or the first SCR 255A. The controller 275 can also know the target temperature at which the reductant deposits inside the first decomposition chamber 250A are reduced. Therefore, based on the exhaust temperature, the current temperature inside the first decomposition chamber 250A, the target temperature inside the first decomposition chamber, and the capacity (e.g., power) of the heater 270, the controller 275 can determine the temperature to which the exhaust needs to be heated and the amount of time it takes for the heater to be activated to reach the target temperature inside the first decomposition chamber. Similarly, based on the exhaust temperature, the temperature inside the first SCR 255A, the desired NOx reduction level, the temperature at which the desired NOx reduction level is achieved, and the capacity of the heater 270, the controller 275 can determine the temperature to which the exhaust needs to be heated and the time it takes for the heater to be activated to achieve the desired NOx reduction level.

[0101] Therefore, by dynamically starting and stopping the heater 270 and controlling the reducing agent injected into the first decomposition chamber 250A in real time (or substantially real time) based on feedback received during operation, the first exhaust path 235 provides a tightly coupled system.

[0102] Regarding the second exhaust path 240, because it is configured for normal operation (e.g., when the exhaust temperature is above 180°C), the second decomposition chamber 250B is not as susceptible to reductant deposits as the first decomposition chamber 250A. Therefore, the reductant can continue to be injected into the second decomposition chamber 250B in liquid form (e.g., using a wet or liquid metering feeder), but if necessary, an evaporator can be associated with the second injector 245B to evaporate the reductant before injection into the second decomposition chamber. Similarly, a standard SCR can continue to be used in the second SCR 255B. The standard SCR may include an SCR catalyst that is not specifically designed for high ammonia storage and / or optimized for low temperatures.

[0103] Furthermore, in some embodiments, the relative dimensions of the first SCR 255A and the second SCR 255B can vary. For example, because the first SCR 255A is used for a shorter time compared to the second SCR 255B (e.g., until the exhaust temperature becomes greater than 180°C), the first SCR can be smaller in size than the second SCR. Similarly, in some embodiments, the first decomposition chamber 250A can be smaller in size than the second decomposition chamber 250B, and the amount of reducing agent injected into each of the first and second decomposition chambers can vary. In some embodiments, a fixed amount of reducing agent can be inserted into the second decomposition chamber 250B, while the controller 275 can dynamically adjust the amount of reducing agent inserted into the first decomposition chamber 250A. In other embodiments, the controller 275 can also dynamically adjust the amount of reducing agent inserted into the second decomposition chamber 250B.

[0104] Now for reference Figure 3 According to some embodiments of this disclosure, example block diagrams of post-processing system 300 are shown. Post-processing system 300 is similar to post-processing system 100 in that post-processing system 300 includes elements similar to those in post-processing system 100, but... Figure 3 Only some of these components are shown. The aftertreatment system 300 includes an engine 305 from which exhaust gas enters an inlet pipe 310. In the inlet pipe 310, the temperature of the exhaust gas is measured by a temperature sensor 315, which in some embodiments may be a thermistor. Exhaust gas enters a DOC 320 from the inlet pipe 310 and optionally passes through a DPF 325 located downstream of the DOC, before being diverted by a selector valve 330 located downstream of the DPF. The DOC 320 is analogous to the oxidation catalyst 120, the DPF 325 is analogous to the particulate filter described above, and the selector valve 330 is analogous to selector valve 230. Therefore, the selector valve 330 is a multi-position valve that diverts exhaust gas between a first exhaust path 335 and a second exhaust path 340 based on instructions received from a controller 345. The controller 345 is analogous to controller 165.

[0105] Similar to the first exhaust path 235, the first exhaust path 335 is configured for use during cold start conditions (e.g., when the exhaust temperature is between approximately 70°C and 180°C). The first exhaust path 335 includes a first injector 350A for injecting a reducing agent into a first decomposition chamber 355A, while the second exhaust path 340 includes a second injector 350B for injecting a reducing agent into a second decomposition chamber 355B. The first exhaust path 335 and the second exhaust path 340 are combined to form a combined exhaust path 360. The combined exhaust path 360 is located downstream of the first decomposition chamber 355A and the second decomposition chamber 355B. The combined exhaust path 360 includes an SCR 365 and an ASC 370 located downstream of the SCR. Exhaust from the ASC 370 is discharged into the atmosphere via an outlet pipe 375.

[0106] Therefore, unlike aftertreatment system 200 (in which each of the first exhaust path 235 and the second exhaust path 240 has its corresponding SCR (e.g., first SCR 255A, second SCR 255B) and ASC (e.g., first ASC 260A, second ASC 260B)), the first exhaust path 335 and the second exhaust path 340 do not include SCR and ASC. Instead, a mixture of exhaust gas and gaseous ammonia from each of the first exhaust path 335 and the second exhaust path 340 flows into the combined exhaust path 360 via SCR 365. SCR 365 oxidizes the ammonia in the presence of an SCR catalyst to reduce NOx in the exhaust gas, and ASC 370 decomposes any unreacted ammonia from the exhaust gas. In some embodiments, SCR 365 may be a standard SCR.

[0107] Furthermore, the selector valve 330 can be configured to divert at least a portion of the exhaust gas to the first exhaust path 335 when the exhaust gas temperature (e.g., measured by temperature sensor 315) is equal to or lower than a predetermined temperature threshold (e.g., 180°C). Specifically, the controller 345 can determine the temperature of the exhaust gas flowing through the inlet pipe 310, and if the exhaust gas temperature is less than or equal to the predetermined temperature threshold (e.g., 180°C), adjust the position of the selector valve 330 to a first open position or a position between the first open position and a second open position to divert at least a portion of the exhaust gas to the first exhaust path 335.

[0108] In some embodiments, the controller 345 may be configured to divert all exhaust gas to the first exhaust path 335 when the exhaust gas temperature is equal to or below a predetermined temperature threshold (e.g., 180°C). In such embodiments, the controller 345 may adjust the position of the selector valve 330 to a first open position. In some embodiments, the controller 345 may be configured to divert only a portion of the exhaust gas to the first exhaust path 335 when the exhaust gas temperature is equal to or below the predetermined temperature threshold (e.g., 180°C). In such embodiments, the controller 345 may adjust the position of the selector valve 330 between a first open position and a second open position based on the portion of exhaust gas that will be diverted to the first exhaust path 335. Furthermore, any exhaust gas not diverted to the first exhaust path 335 is diverted to the second exhaust path 340.

[0109] The portion of exhaust gas diverted to the first exhaust path 335 can be predetermined. For example, in some embodiments, when the exhaust gas temperature is equal to or below a predetermined temperature threshold (e.g., 180°C), approximately 50% of the exhaust gas can be diverted to the first exhaust path 335. The remaining approximately 50% of the exhaust gas can be diverted to the second exhaust path 340. To divert approximately 50% of the exhaust gas to the first exhaust path 335, the controller 345 can adjust the position of the selector valve 330 to approximately midway between a first open position and a second open position. In other embodiments, different proportions of exhaust gas can be diverted to the first exhaust path 335. Therefore, when the exhaust gas temperature is less than or equal to the predetermined temperature threshold (e.g., 180°C), by changing the position of the selector valve 330 between the first open position and the second open position, the controller 345 can divert a portion of the exhaust gas to the first exhaust path 335 and a portion of the exhaust gas to the second exhaust path 340. When the exhaust gas temperature is above the predetermined temperature threshold (e.g., 180°C), the controller 345 can divert all the exhaust gas to the second exhaust path 340.

[0110] Furthermore, although the exhaust temperature on which the controller 345 controls the selector valve 330 is based is measured in the inlet pipe 310, in some embodiments, the exhaust temperature may be measured at the outlet of DOC 320 and / or the outlet of DPF 325.

[0111] Furthermore, the exhaust gas diverted to the first exhaust path 335 can be heated by heater 380. Heater 380 can be controlled by controller 345 to reduce reductant deposits in the first decomposition chamber 355A. Therefore, based on the temperature of the exhaust gas entering the first exhaust path 335, the temperature of the exhaust gas in the first decomposition chamber 355A, the desired temperature within the first decomposition chamber, the capacity of heater 380, and any other inputs that may contribute to improving the efficiency of the first decomposition chamber, the controller can activate the heater for a period of time to heat the interior of the first decomposition chamber. In some embodiments, the first decomposition chamber 355A can also be configured to receive the reductant in evaporated form using an evaporator coupled to the first injector 350A to reduce reductant deposition on the walls of the first decomposition chamber. Similarly, in some embodiments, the reductant can be injected in liquid form into the second decomposition chamber 355B using a wet or liquid metering feeder. In some embodiments, the second injector 350B can be coupled to an evaporator to evaporate the reductant before it is inserted into the second decomposition chamber 355B.

[0112] Furthermore, in some embodiments, as described above, the controller 345 may be configured to dynamically adjust the amount of reducing agent inserted into the first decomposition chamber 355A and / or the second decomposition chamber 355B. For example, the controller 345 may receive data from one or more components of the first exhaust path 335 and the combined exhaust path 360 in real time or substantially in real time to dynamically change the amount of reducing agent inserted into the first decomposition chamber 355A. Similarly, the controller 345 may receive data from one or more components of the second exhaust path 340 and the combined exhaust path 360 to dynamically change the amount of reducing agent inserted into the second decomposition chamber 355B. Thus, the first exhaust path 335 together with the combined exhaust path 360 forms a first parallel tightly coupled system, while the second exhaust path 340 together with the combined exhaust path forms another parallel tightly coupled system.

[0113] refer to Figure 4A and Figure 4B According to some embodiments of this disclosure, example block diagrams of post-processing systems 400 and 400' are shown respectively. Post-processing systems 400 and 400' are similar to post-processing system 100 in that they include elements similar to those in post-processing system 100, but... Figure 4A and Figure 4B Only some of these components are shown. Post-processing system 400 shows a first series of embodiments, while post-processing system 400' shows a second series of embodiments.

[0114] For details, please refer to the following: Figure 4AThe aftertreatment system 400 includes an engine 405 from which exhaust gas enters an inlet pipe 410. In the inlet pipe 410, the temperature of the exhaust gas is measured by a temperature sensor 415, which in some embodiments may be a thermistor. The exhaust gas is diverted from the inlet pipe 410 by a selector valve 420. The selector valve 420 is similar to selector valve 230. The selector valve 420 diverts the exhaust gas from the inlet pipe 410 to either a first exhaust path 425 or a second exhaust path 430. The first exhaust path 425 and the second exhaust path 430 are combined to form a combined exhaust path 435 downstream of both the first and second exhaust paths.

[0115] The first exhaust path 425 can be used under cold start conditions to heat the exhaust gas to a desired temperature via heater 440 before it enters the combined exhaust path 435. Therefore, when the exhaust gas temperature is at or below a predetermined temperature threshold (e.g., 180°C), controller 445 can adjust the position of selector valve 420 to a first open position to divert all exhaust gas into the first exhaust path 425. When the exhaust gas temperature is above the predetermined temperature threshold (e.g., 180°C), controller 445 can adjust the position of selector valve 420 to a second open position to divert all exhaust gas into the second exhaust path 430. In the first exhaust path 425, the exhaust gas is heated to a desired temperature by heater 440. The temperature to which the exhaust gas is heated may depend on the desired target temperature in one or more elements of the combined exhaust path 435. In some embodiments, heaters may also be provided in the second exhaust path 430 and / or the combined exhaust path 435.

[0116] Heated exhaust gas from the first exhaust path 425 enters the combined exhaust path 435, specifically the DOC 450 of the combined exhaust path. Exhaust gas may optionally flow from the DOC 450 to the DPF 455 located downstream of the DOC. The DOC 450 is similar to the oxidation catalyst 120, and the DPF 455 is similar to the one described above. Figure 1 The particulate filter under discussion. Heated exhaust gas from DPF 455 is mixed with a reducing agent in the first decomposition chamber 460. The reducing agent is inserted into the first decomposition chamber 460 by a first injector 465. The reducing agent can be inserted in liquid form (e.g., using a wet or liquid metering feeder) or in evaporative form (e.g., using an evaporator). The mixture of exhaust gas and reducing agent is diverted to a first SCR 470 and an ASC 475 via a combined exhaust gas path 435 before being released into the atmosphere via an outlet pipe 480. The first SCR 470 can be a standard SCR.

[0117] The controller 445 can be configured to heat the exhaust gas in the first exhaust path 425 to achieve a target temperature within the first decomposition chamber 460 and / or the first SCR 470. By positioning the first decomposition chamber 460 and the first SCR 470 in the combined exhaust path 435, the same decomposition chamber and SCR can be used in both the first exhaust path 425 and the second exhaust path 430. Furthermore, by using the heater 440 to heat the exhaust gas diverted to the first exhaust path 425 to achieve the target temperature within the first decomposition chamber 460 and / or the first SCR 470, the operating efficiency of the first decomposition chamber and / or the first SCR can be increased during cold start conditions.

[0118] When the controller 445 directs the exhaust gas to the second exhaust path 430, the exhaust gas enters the second decomposition chamber 485A, which receives the reducing agent via the second injector 485B. The second decomposition chamber 485A can be configured to receive the reducing agent in liquid or evaporative form. In some embodiments, mixing of the exhaust gas and gaseous ammonia from the reducing agent can be facilitated by using a mixer 490 located downstream of the second decomposition chamber 485A. Although not shown, the mixer may also be used in conjunction with... Figure 2 and Figure 3 In this embodiment, the first and second decomposition chambers are used in combination. The mixture of exhaust gas and reducing agent from mixer 490 is diverted to the second SCR 495 before being conveyed to the combined exhaust gas path 435. In the combined exhaust gas path 435, the exhaust gas passes through the first decomposition chamber 460, the first SCR 470, and the ASC 475 before being discharged via outlet pipe 480.

[0119] Therefore, exhaust gas from inlet pipe 410 passes through either the first exhaust path 425 or the second exhaust path 430 before passing through the combined exhaust path 435. Furthermore, in some embodiments, controller 445 may be configured to dynamically adjust the amount of reductant inserted into the first decomposition chamber 460 and / or the second decomposition chamber 485A based on feedback received from one or more components of the aftertreatment system 400. For example, when exhaust gas is diverted through the first exhaust path 425, controller 445 may dynamically adjust the amount of reductant inserted into the first decomposition chamber 460 based on feedback from one or more components of the first exhaust path 425 and the combined exhaust path 435. When exhaust gas is diverted through the second exhaust path 430, controller 445 may dynamically adjust the amount of reductant inserted into the first decomposition chamber 460 and / or the second decomposition chamber 485A based on feedback from one or more components of the second exhaust path and the combined exhaust path 435.

[0120] Figure 4B The embodiments are largely similar to Figure 4A In the embodiments, except for the first exhaust path and the second exhaust path in Figure 4B Conversely, the aftertreatment system 400' includes an engine 405' from which exhaust gas enters an inlet pipe 410'. The temperature of the exhaust gas can be measured in the inlet pipe 410' by a temperature sensor 415', which in some embodiments may be a thermistor. A selector valve 420' can divert the exhaust gas to either a first exhaust path 425' or a second exhaust path 430'. The first exhaust path 425' and the second exhaust path 430' can be combined to form a combined exhaust path 435' downstream of the first and second exhaust paths. When the controller 440' determines that the exhaust gas temperature measured by the temperature sensor 415' is equal to or less than a predetermined temperature threshold (e.g., 180°C), the controller can adjust the position of the selector valve 420' to a first open position to divert all exhaust gas to the first exhaust path 425'. When the controller 440' determines that the exhaust gas temperature is greater than the predetermined temperature threshold (e.g., 180°C), the controller can adjust the position of the selector valve 420' to a second open position to divert all exhaust gas to the second exhaust path 430'. Exhaust gas enters the combined exhaust path 435' from either the first exhaust path 425' or the second exhaust path 430'.

[0121] The combined exhaust path 435' may include a DOC 445', a DPF 450' downstream of the DOC, a first decomposition chamber 455' downstream of the DPF, an injector 460' for injecting a reducing agent into the first decomposition chamber, a first SCR 465' downstream of the first decomposition chamber, and an ASC 470' downstream of the first SCR. The exhaust gas is discharged into the atmosphere through an outlet pipe 475' downstream of the ASC 470'.

[0122] The first exhaust path 425' includes a heater 480' configured to heat the exhaust gas diverted to the first exhaust path by the selector valve 420'. The heated exhaust gas is mixed with gaseous ammonia in a second decomposition chamber 485A', which receives a reducing agent via a second injector 485B'. A mixer 490' can facilitate the mixing of the exhaust gas with the gaseous ammonia. A second SCR 495' then oxidizes at least a portion of the gaseous ammonia to reduce NOx in the exhaust gas before it flows into the combined exhaust path 435' for further processing. A controller 440' can heat the exhaust gas to the desired temperatures in the second decomposition chamber 485A', the second SCR 495', the first decomposition chamber 455', and / or the first SCR 465'. Furthermore, as described above, the controller 440' can dynamically adjust the amount of reducing agent inserted into the first decomposition chamber 455' and / or the second decomposition chamber 485A' based on feedback from one or more inputs. In some embodiments, the heater may also be disposed in the second exhaust path 430' and / or the combined exhaust path 435'.

[0123] Turning Figure 5 According to some embodiments of this disclosure, an example flowchart outlining a process 500 for treating exhaust gas using an aftertreatment system is shown. Process 500 can be implemented using the aforementioned aftertreatment systems 200, 300, 400, 400', and particularly by controllers of those aftertreatment systems (e.g., controllers 275, 345, 445, 440'). The process begins at operation 505, where the engine (e.g., engine 205, engine 305, engine 405, engine 405') discharges exhaust gas into intake manifolds (e.g., intake manifolds 210, 310, 410, 410'). At operation 510, the controller receives the exhaust gas temperature in the intake manifold. For example, controller 275 may receive the exhaust gas temperature in intake manifold 210 as measured by temperature sensor 215. Similarly, controller 345 can receive the exhaust temperature in inlet pipe 310 measured by temperature sensor 315, controller 445 can receive the exhaust temperature in inlet pipe 410 measured by temperature sensor 415, and controller 440' can receive the exhaust temperature in inlet pipe 410' measured by temperature sensor 415'.

[0124] In other embodiments, controller 275 may additionally or alternatively determine exhaust temperatures at other locations (e.g., the outlet of DPF 225 and / or the outlet of DOC 220). Similarly, in some embodiments, controller 345 may additionally or alternatively determine exhaust temperatures at the outlet of DOC 320 and / or the outlet of DPF 325. When the controller determines exhaust temperatures at multiple locations, the controller may apply a mathematical function (e.g., an average value) to the various determined exhaust temperatures and adjust selector valves (e.g., selector valve 230, selector valve 330, selector valve 420, selector valve 420') based on the calculated average temperature.

[0125] In operation 515, the controller determines whether the exhaust temperature determined in operation 510 is less than a predetermined temperature threshold (e.g., 180°C). If the controller determines that the exhaust temperature is greater than the predetermined threshold, then in operation 520, the controller adjusts the position of the selector valve to a second open position to divert all exhaust to a second exhaust path (e.g., second exhaust path 240, second exhaust path 340, second exhaust path 430, second exhaust path 430'). Alternatively, if in operation 515, the controller determines that the exhaust temperature is equal to or less than the predetermined temperature threshold, then in operation 525, the controller adjusts the position of the selector valve to a first open position or a position between the first open position and the second open position to divert at least a portion of the exhaust to a first exhaust path (e.g., first exhaust path 235, first exhaust path 335, first exhaust path 425, first exhaust path 425'), as described above.

[0126] For example, in aftertreatment systems 200, 400, and 400', after determining that the exhaust temperature is equal to or below a predetermined temperature threshold, controllers 275, 445, and 440' respectively redirect all exhaust to the corresponding first exhaust path 235, first exhaust path 425, and first exhaust path 425'. Conversely, in aftertreatment system 300, after the controller determines that the exhaust temperature is equal to or below the predetermined temperature threshold, controller 345 redirects only a predetermined portion of the exhaust to the first exhaust path 335. Controller 345 redirects the remaining portion of the exhaust to the second exhaust path 340.

[0127] In some embodiments, the controller may also rely on inputs other than exhaust temperature to control the selector valve. For example, in some embodiments, the controller may receive input from NOx sensors located at the inlet and / or outlet of the DOC (e.g., DOC 220, DOC 320, DOC 450, DOC 445'), the inlet and / or outlet of the DPF (e.g., DPF 225, DPF 325, DPF 450', DPF 455), and / or located at the outlet pipe (e.g., outlet pipe 265, outlet pipe 375, outlet pipe 475', outlet pipe 480) to determine the ammonia to NOx ratio (ANR) of the exhaust gas. In other embodiments, the controller may receive input from NOx sensors located at other or additional locations to determine the ANR. Based on the ANR and exhaust temperature, the controller may control the selector valve to divert the exhaust gas between a first exhaust path and / or a second exhaust path, thereby achieving a desired NOx reduction efficiency. In some embodiments, the controller may rely solely on the ANR to control the selector valve. In other embodiments, the controller may use other or additional inputs to control the selector valve.

[0128] Furthermore, in operation 530, when the exhaust gas is diverted to the first exhaust path, the controller activates the heater (e.g., heater 270, heater 380, heater 440, or heater 480') to heat the exhaust gas diverted to the first exhaust path. As described above, the controller can activate the heater to heat the exhaust gas until the exhaust gas temperature reaches a desired temperature. The desired temperature can be based on the desired temperature in the decomposition chamber and / or the SCR in which the exhaust gas will flow. The controller can receive feedback data regarding the current operating status of the decomposition chamber, the SCR system, and / or other components to determine the desired temperature. After determining that the desired temperature has been reached, the controller deactivates the heater in operation 535. Process 500 ends in operation 540.

[0129] It should be noted that the term "example" used herein to describe various embodiments is intended to indicate possible examples, representations, and / or illustrations of possible embodiments (and such term is not intended to mean that such embodiments must be particular or best examples).

[0130] As used herein, the term “about” generally refers to plus or minus 10% of the value stated. 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.

[0131] As used herein, the term "connection" refers to the direct or indirect linking of two components to each other. Such a connection can be fixed (e.g., permanent) or movable (e.g., removable or releasable). Such a connection can be achieved by the two components, or two components and any additional intermediate components, being integrally formed into a single unit, or by the two components, or two components and any additional intermediate components, being attached to each other.

[0132] It is important to note that the structures and arrangements of the various exemplary embodiments are merely illustrative. While only a few embodiments have been described in detail in this disclosure, those skilled in the art will readily recognize that many modifications (e.g., variations in the size, dimensions, structure, shape and proportion of various elements, values ​​of parameters, mounting arrangements, use of materials, color, orientation, etc.) are possible without substantially departing from the novel teachings and advantages of the subject matter described herein. Furthermore, it should be understood that features from one embodiment disclosed herein can be combined with features from other embodiments disclosed herein, as will be understood by those skilled in the art. Other substitutions, modifications, variations, and omissions may also be made in the design, operation, and arrangement of the various exemplary embodiments without departing from the scope of these embodiments.

[0133] While this specification contains numerous specific implementation details, these should not be construed as limiting any embodiment or the scope of the claims, but rather as descriptions of features characteristic of a particular implementation of a particular embodiment. Certain features described in the context of individual implementations may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented individually or in any suitable sub-combination in multiple implementations. Furthermore, although features may be described above as functioning in certain combinations, and even initially claimed in this way, in some cases, one or more features from a claimed combination may be removed from that combination, and the claimed combination may refer to a sub-combination or a variation of a sub-combination.

Claims

1. An aftertreatment system, comprising: a first exhaust path including a heater; a second exhaust path including a first decomposition chamber configured to receive a reductant and a first selective catalytic reduction catalyst downstream of the first decomposition chamber; a combined exhaust path downstream of the first exhaust path and the second exhaust path, the combined exhaust path configured to receive exhaust from both the first exhaust path and the second exhaust path; a selector valve configured to divert exhaust between the first exhaust path and the second exhaust path based on a temperature of the exhaust; and a controller programmed to control the selector valve such that: when the temperature of the exhaust is equal to or less than a predetermined temperature threshold, the selector valve diverts exhaust to the first exhaust path; and when the temperature of the exhaust is greater than the predetermined temperature threshold, the selector valve diverts exhaust to the second exhaust path; wherein: the heater is configured to heat exhaust received in the first exhaust path; the first decomposition chamber is configured to receive exhaust that has been diverted to the second exhaust path by the selector valve; and the first selective catalytic reduction catalyst is configured to receive exhaust from the first decomposition chamber.

2. The aftertreatment system of claim 1, wherein: the combined exhaust path further comprises: a second decomposition chamber to receive exhaust from the first exhaust path and the second exhaust path; and a second selective catalytic reduction catalyst downstream of the second decomposition chamber to receive exhaust from the second decomposition chamber. the combined exhaust path further comprises an ammonia slip catalyst downstream of the second selective catalytic reduction catalyst. the combined exhaust path further comprises an oxidation catalyst upstream of the second decomposition chamber.

3. The aftertreatment system of claim 2, wherein, the combined exhaust path further comprises a particulate filter downstream of the oxidation catalyst and upstream of the second decomposition chamber.

4. The aftertreatment system of claim 2, wherein, each of the first decomposition chamber and the second decomposition chamber is configured to receive a reductant in liquid form or vaporized form.

5. The aftertreatment system of claim 4, wherein, the controller is further programmed to dynamically adjust an amount of reductant inserted into the first decomposition chamber and the second decomposition chamber based on feedback from one or more components of the aftertreatment system.

6. The aftertreatment system of claim 2, wherein, each of the first selective catalytic reduction catalyst and the second selective catalytic reduction catalyst includes a copper-based catalyst, an iron-based catalyst, or a vanadium-based catalyst.

7. The aftertreatment system of claim 2, wherein, the first selective catalytic reduction catalyst includes a mixer to mix exhaust with reductant.

8. The aftertreatment system of claim 2, wherein, the predetermined temperature threshold is in a range of 70 °C to 180 °C.

9. The aftertreatment system of claim 1, wherein, 11. A method for operating an aftertreatment system, comprising:

10. The aftertreatment system of claim 1, wherein, determining, by a controller associated with an aftertreatment system, a temperature of exhaust; comparing, by the controller, the temperature of the exhaust to a predetermined temperature threshold; ​ ​ when the temperature of the exhaust gas is equal to or less than the predetermined temperature threshold, adjusting a selector valve to a first position so as to divert exhaust gas to a first exhaust gas path, and heating the exhaust gas in the first exhaust gas path; and when the temperature of the exhaust gas is greater than the predetermined temperature threshold, adjusting the selector valve to a second position so as to divert exhaust gas to a second exhaust gas path; wherein: a first decomposition chamber of the second exhaust gas path is configured to receive exhaust gas that has been diverted to the second exhaust gas path by the selector valve; a first selective catalytic reduction catalyst of the second exhaust gas path is configured to receive exhaust gas from the first decomposition chamber; and exhaust gas from the first exhaust gas path and the second exhaust gas path is diverted to a combined exhaust gas path that is downstream of the first exhaust gas path and the second exhaust gas path and is configured to receive exhaust gas from the first exhaust gas path and the second exhaust gas path.

12. The method of claim 11, further comprising dynamically adjusting, by the controller, an amount of reductant injected into the first decomposition chamber based on feedback from one or more components of the aftertreatment system.

13. The method of claim 12, further comprising injecting, by the controller, the amount of reductant into the first decomposition chamber in a liquid form or a vaporized form.

14. The method of claim 11, further comprising dynamically adjusting, by the controller, an amount of reductant injected into a second decomposition chamber based on feedback from one or more components of the aftertreatment system, wherein the second decomposition chamber is located in the combined exhaust gas path upstream of a second selective catalytic reduction catalyst that receives exhaust gas from the second decomposition chamber.

15. The method of claim 11, wherein, the predetermined temperature threshold is in a range of 70 °C to 180 °C.

16. A non-transitory computer-readable medium comprising computer-readable instructions stored thereon that, when executed by a processor of an aftertreatment system, cause the processor to: determine a temperature of exhaust gas; compare the temperature of the exhaust gas to a predetermined temperature threshold; when the temperature of the exhaust gas is equal to or less than the predetermined temperature threshold, adjusting a selector valve to a first position so as to divert the exhaust gas to a first exhaust gas path, and heating the exhaust gas in the first exhaust gas path; and when the temperature of the exhaust gas is greater than the predetermined temperature threshold, adjusting the selector valve to a second position so as to divert exhaust gas to a second exhaust gas path; wherein: a first decomposition chamber of the second exhaust gas path is configured to receive exhaust gas that has been diverted to the second exhaust gas path by the selector valve; a first selective catalytic reduction catalyst of the second exhaust gas path is configured to receive exhaust gas from the first decomposition chamber; and exhaust gas from the first exhaust gas path and the second exhaust gas path is diverted to a combined exhaust gas path that is downstream of the first exhaust gas path and the second exhaust gas path and is configured to receive exhaust gas from the first exhaust gas path and the second exhaust gas path.

17. The non-transitory computer-readable medium of claim 16, wherein, the processor further executes the computer-readable instructions to dynamically adjust an amount of reductant injected into the first decomposition chamber based on feedback from one or more components of the aftertreatment system.

18. The non-transitory computer-readable medium of claim 17, wherein, The processor also executes computer-readable instructions to inject the amount of reductant in liquid form or vaporized form into the first decomposition chamber.

19. The non-transitory computer-readable medium of claim 16, wherein, The processor also executes computer-readable instructions to dynamically adjust the amount of reductant inserted into a second decomposition chamber based on feedback from one or more components of the aftertreatment system, and wherein the second decomposition chamber is located in the combined exhaust path upstream of a second selective catalytic reduction catalyst that receives exhaust gas from the second decomposition chamber.

20. The non-transitory computer-readable medium of claim 16, wherein, The predetermined temperature threshold is in a range of 70 °C to 180 °C. The predetermined temperature threshold is in a range of 70 °C to 180 °C.

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