SYSTEMS AND METHODS FOR MULTIPOINT REDUCTANT INSERTION

An aftertreatment system includes a multipoint injector configured to be operatively coupled to an exhaust tube of the aftertreatment system. The multipoint injector comprises an injector body having a circumferential wall. A plurality of orifices extend through the circumferential wall of the injector body. Each of the plurality of orifices is located at a different circumferential position of the circumferential wall and is configured to insert reductant into an exhaust gas flow path defined by the exhaust tube.

TECHNICAL FIELD

The present disclosure relates generally to aftertreatment systems for use with internal combustion (IC) engines.

BACKGROUND

Exhaust aftertreatment systems are used to receive and treat exhaust gas generated by IC engines. Generally exhaust gas aftertreatment systems include any of several different components to reduce the levels of harmful exhaust emissions present in the exhaust gas. For example, certain exhaust gas aftertreatment systems for diesel-powered IC engines include a selective catalytic reduction (SCR) system including a catalyst formulated to convert NOx (NO and NO2in some fraction) into harmless nitrogen gas (N2) and water vapor (H2O) in the presence of ammonia (NH3). Generally in such aftertreatment systems, an exhaust reductant, (e.g., a diesel exhaust fluid such as urea) is injected into the SCR system to provide a source of ammonia, and mixed with the exhaust gas to partially reduce the NOx gases. The reduction byproducts of the exhaust gas are then fluidically communicated to the catalyst included in the SCR system to decompose substantially all of the NOx gases into relatively harmless byproducts which are expelled out of the aftertreatment system.

A reductant is generally inserted into the SCR system as the source of ammonia to facilitate the decomposition of constituents such as NOx gases of the exhaust gas (e.g., a diesel exhaust gas) by the catalyst included in the SCR system. Inefficient mixing of the reductant with exhaust gas, or impinging of the reductant on sidewalls of an exhaust tube may result in formation of reductant deposits (e.g., due to crystallization of the reductant) in the exhaust tube and components of the aftertreatment system. Reductant deposits reduce the efficiency of the aftertreatment system and may cause clogging of the exhaust tube demanding frequent cleaning of the exhaust tube. The reductant deposits may also accumulate in downstream components, for example, the SCR system and may reduce a catalytic efficiency thereof. Reductant deposits therefore cause frequent maintenance to be performed on the aftertreatment system increasing maintenance costs.

SUMMARY

Embodiments described herein relate generally to systems and methods for inserting a reductant into an aftertreatment system, and in particular to reductant insertion systems that include a multipoint injector having a plurality of circumferentially located orifices and a reductant distributor coupled to the multipoint injector and configured to selectively provide reductant to one or more orifices of the multipoint injector.

In some embodiments, a multipoint injector configured to be operatively coupled to an exhaust tube of an aftertreatment system comprises an injector body having a circumferential wall. A plurality of orifices extend through the circumferential wall of the injector body, each being located at a different circumferential position of the circumferential wall and being configured to insert reductant into an exhaust gas flow path defined by the exhaust tube.

In some embodiments, a method for inserting a reductant into an exhaust tube of an aftertreatment system via a multipoint injector fluidly coupled to the exhaust tube comprises determining an operating parameter of the exhaust gas. The multipoint injector comprises an injector body having a circumferential wall and a plurality of orifices extending through the circumferential wall, each being located at a different circumferential position of the circumferential wall. The reductant is inserted through at least a portion of the plurality of orifices into a flow path of an exhaust gas flowing through the exhaust tube based on the operating parameter.

DETAILED DESCRIPTION

Embodiments described herein relate generally to systems and methods for delivering a reductant to an aftertreatment system, and in particular to reductant insertion systems that include a multipoint injector having a plurality of circumferentially located orifices and a reductant distributor coupled to the multipoint injector and configured to selectively provide reductant to one or more orifices of the multipoint injector.

Reductant injectors are used to insert reductant into a flow path of an exhaust gas flowing through an aftertreatment system. The reductant may form reductant deposits (e.g., due to crystallization or incomplete decomposition of the reductant) in an exhaust tube and/or components of the aftertreatment system. Conventional reductant injectors generally insert reductant into the same location of an exhaust tube to which the injector is coupled. This causes reductant to repeatedly impinge on the same location of a wall of the exhaust tube which increases deposition of reductant deposits in the exhaust tube. Reductant deposits reduce the efficiency of the aftertreatment system and may cause clogging of the exhaust tube demanding frequent cleaning of the exhaust tube. The reductant deposits may also accumulate in downstream components, for example, the SCR system and may reduce a catalytic efficiency thereof. Reductant deposits therefore cause frequent maintenance to be performed on the aftertreatment system increasing maintenance costs.

Various embodiments of the multipoint injector described herein may provide benefits including, for example: (1) providing insertion of reductant at a plurality of circumferential locations causing better mixing of the reductant with the exhaust gas so to reduce crystallization and formation of reductant deposits; (2) allowing selective insertion of reductant at various spray angles and droplet size to provide different reductant droplet size and spray angles; (3) reducing a rate of impingement of the reductant at the same location of the exhaust tube by allowing cycling of insertion of the reductant through the orifices, thereby reducing reductant deposits and accumulation on any one location of the aftertreatment system; (4) inserting reductant through smaller orifices provided in the multipoint injector which provides smaller reductant droplets facilitating reductant evaporation and reducing reductant deposits; (5) allowing control of droplet size and pattern based on reductant demand; (6) reducing maintenance intervals therefore, reducing maintenance costs; and (7) removable coupling of the multipoint injector allowing easy replacement and further reducing maintenance costs.

FIG. 1is a schematic illustration of an aftertreatment system100, according to an embodiment. The aftertreatment system100is configured to receive an exhaust gas (e.g., a diesel exhaust gas) from an engine10and the reduce constituents of the exhaust gas such as, for example, NOx gases, CO, etc. The aftertreatment system100includes a reductant storage tank110, a reductant insertion assembly112, a reductant insertion system120comprising a multipoint injector140and a reductant distributor130, a SCR system150and a controller170.

The engine10may be an IC engine, for example a diesel engine, a gasoline engine, a natural gas engine, a biodiesel engine, a dual fuel engine, an alcohol engine, an E85 or any other suitable internal combustion engine.

The reductant storage tank110contains an exhaust reductant formulated to facilitate decomposition (e.g., reduction) of the constituents of the exhaust gas (e.g., NOx gases) by a catalyst154included in the SCR system150. In embodiments in which the exhaust gas is a diesel exhaust gas, the exhaust reductant can include a diesel exhaust fluid (DEF) which provides a source of ammonia. Suitable DEFs can include urea, aqueous solution of urea or any other DEF (e.g., the DEF available under the tradename ADBLUE®). In particular embodiments, the reductant includes an aqueous urea solution containing 32.5% urea and 67.5% de-ionized water. In other embodiments, the reductant includes aqueous urea solution containing 40% urea and 60% de-ionized water.

The SCR system150is configured to receive and treat the exhaust gas (e.g., a diesel exhaust gas) flowing through the SCR system150via an exhaust tube102defining an exhaust flow path for communicating the exhaust gas from the engine10to the SCR system150and/or any other components positioned therewithin or downstream thereof. The SCR system150is fluidly coupled to the reductant storage tank110so as to receive the reductant therefrom via the reductant insertion assembly112, as described herein. The aftertreatment system100may also include an outlet tube104positioned downstream of the SCR system150and structured to expel treated exhaust gas into the environment.

A first sensor103may be positioned in the exhaust tube102. The first sensor103may include, for example, a NOx sensor (e.g., a physical or virtual NOx sensor), an oxygen sensor, a particulate matter sensor, a carbon monoxide sensor, a temperature sensor, a pressure sensor, any other sensor or a combination thereof configured to measure one or more operational parameters of the exhaust gas. Such operating parameters may include, for example, an amount of NOx gases in the exhaust gas, a temperature of the exhaust gas, a flow rate and/or pressure of the exhaust gas.

A second sensor105may be positioned in the outlet tube104. The second sensor105may comprise a second NOx sensor configured to determine an amount of NOx gases expelled into the environment after passing through the SCR system150. In other embodiments, the second sensor105may comprise a PM sensor configured to determine an amount of PM (e.g., soot or ash included in the exhaust gas). In still other embodiments, the second sensor105may comprise an ammonia sensor configured to measure an amount of ammonia in the exhaust gas flowing out of the SCR system150, i.e., determine the ammonia slip. The ammonia slip may be used as a measure of catalytic efficiency of the SCR system150, for adjusting an amount of reductant to be inserted into the SCR system150, and/or for adjusting a temperature of the SCR system150so as to allow the SCR system150to effectively use the ammonia for catalytic decomposition of the NOx gases included in the exhaust gas flowing therethrough. In some embodiments, an ammonia oxide (AMOx) catalyst may be positioned downstream of the SCR system150, for example, in the outlet tube104so as to decompose any unreacted ammonia in the exhaust gas downstream of the SCR system150.

The SCR system150comprises a housing152containing at least one catalyst154. In some embodiments, the SCR system150may comprise a selective catalytic reduction filter (SCRF), or any other aftertreatment component configured to decompose constituents of the exhaust gas (e.g., NOx gases such as such nitrous oxide, nitric oxide, nitrogen dioxide, etc.), flowing therethrough in the presence of a reductant, as described herein. Any suitable catalyst154can be used such as, for example, platinum, palladium, rhodium, cerium, iron, manganese, copper, and/or vanadium based catalysts (including combinations thereof).

The catalyst154can be disposed on a suitable substrate such as, for example, a ceramic (e.g., cordierite) or metallic (e.g., kanthal) monolith core which can, for example, define a honeycomb structure. A washcoat can also be used as a carrier material for the catalyst154. Such washcoat materials can include, for example, aluminum oxide, titanium dioxide, silicon dioxide, any other suitable washcoat material, or a combination thereof. The exhaust gas can flow over and about the catalyst154such that NOx gases included in the exhaust gas are further reduced to yield an exhaust gas which is substantially free of carbon monoxide and NOx gases.

In various embodiments, the aftertreatment system100may also include other aftertreatment components such as, for example, an oxidation catalyst (e.g., a diesel oxidation catalyst), one or more particulate matter filters, ammonia oxidation catalysts, mixers, baffle plates, or any other suitable aftertreatment component. Such aftertreatment components may be positioned upstream (e.g., positioned within the exhaust tube102) or downstream of the SCR system150.

The reductant insertion assembly112is fluidly coupled to the reductant storage tank110. The reductant insertion assembly112is configured to provide the reductant to the reductant insertion system120positioned upstream of the SCR system150. The reductant insertion assembly112may comprise various structures to facilitate receipt of the reductant from the reductant storage tank110and delivery to the SCR system150.

In various embodiments, the reductant insertion assembly112may also include one or more pumps (e.g., a diaphragm pump, a positive displacement pump, a centrifugal pump, a vacuum pump, etc.) for delivering the reductant to SCR system150at an operating pressure and/or flow rate. The reductant insertion assembly112may also include filters and/or screens (e.g., to prevent solid particles of the reductant or contaminants from flowing into the one or pumps) and/or valves (e.g., check valves) to receive reductant from the reductant storage tank110. Screens, check valves, pulsation dampers, or other structures may also be positioned downstream of the one or more pumps of the reductant insertion assembly112and configured to remove contaminants and/or facilitate delivery of the reductant to the SCR system150.

In various embodiments, the reductant insertion assembly112may also comprise a bypass line structured to provide a return path of the reductant from the one or more pumps to the reductant storage tank110. A valve (e.g., an orifice valve) may be provided in the bypass line. In various embodiments, the reductant insertion assembly112may also comprise a blending chamber structured to receive pressurized reductant from a metering valve at a controllable rate. The blending chamber may also be structured to receive air (e.g., compressed air or portion of the exhaust gas), or any other inert gas (e.g., nitrogen), for example, from an air supply unit so as to deliver a combined flow of the air and the reductant to the SCR system150through the reductant port.

The multipoint injector140is operatively coupled to the exhaust tube102and configured to provide multipoint insertion of the reductant into the exhaust gas flow path. The multipoint injector140comprises an injector body141having a circumferential wall. For example, the injector body141may comprise a ring shaped member positioned within the exhaust tube102or coupled thereto. In some embodiments, the exhaust tube102may comprise an exhaust tube first portion106positioned upstream of the injector body141and an exhaust tube second portion108positioned downstream of the injector body141such that the injector body141defines a channel therethrough, the channel forming a portion of the exhaust gas flow path.

In some embodiments, the multipoint injector140may also include a plurality of flanges positioned at axial ends of the injector body141and extending radially outwards from the injector body141. The flanges abut corresponding axial ends of the exhaust tube first portion106and the exhaust tube second portion108and are coupled thereto. In some embodiments, the injector body141may be removably coupled to the exhaust tube first and second portions106and108, for example, via screws, nuts, bolts, coupling bands or any other suitable coupling mechanism. In other embodiments, the injector body141may be fixedly coupled to the exhaust tube first and second portions106and108, for example, welded thereto.

As shown inFIG. 1, a plurality of orifices142extend through a circumferential wall of the injector body141. Each of the plurality of orifices142is configured to receive reductant through a corresponding reductant delivery line139for independently inserting reductant into the exhaust gas flow path. Each of the plurality of orifices142is located at a different circumferential position of the circumferential wall of the injector body141and is configured to radially insert reductant into the exhaust gas flow path defined by the exhaust tube102, i.e., the channel defined by the injector body141. Any number of orifices142may be defined through the circumferential wall, for example 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or even more.

The plurality of orifices may have a small diameter, for example, in a range of 0.40 mm to 0.55 mm. The small diameter of the orifices142produce a small droplet size of the reductant which rapidly evaporates in the exhaust gas, therefore enhancing mixing and reducing reductant deposits. At least a portion of the plurality of orifices142are inclined with respect to a flow axis of the exhaust gas flow path. In some embodiments, each of the plurality of orifices are inclined at the same angle with respect to a flow axis of the exhaust gas flow path. In some embodiments, each of the plurality of orifices142may have the same size (e.g., the same length or diameter). In other embodiments, at least some of the plurality of orifices142may have a different size from other orifices142. The different sized orifices142may be selectively activated to vary the droplet size, volume and/or flow rate of the reductant inserted into the exhaust gas flow path (e.g., based on one or more operating parameters of the aftertreatment system100such as exhaust gas temperature, flow rate, pressure, amount of NOx gases in exhaust gas, etc.).

In some embodiments, a plurality of reductant delivery lines139may be used to deliver the reductant from the reductant insertion assembly112to a corresponding orifice142. A reductant distributor130may be used to provide reductant to each of the plurality of orifices142. For example, as shown inFIG. 1, the reductant insertion system120also comprises the reductant distributor130configured to selectively provide reductant to the plurality of orifices142. The reductant distributor130comprises an inlet131fluidly coupled to the reductant insertion assembly112via a reductant receiving line114and configured to receive the reductant from the reductant insertion assembly112. The reductant distributor130also comprises a plurality of outlets136coupled via a corresponding reductant delivery line139to a corresponding orifice142of the plurality of orifices142.

The reductant distributor130also comprises a plurality of valves138. Each of the plurality of valves138is operatively coupled to a corresponding outlet136and configured to be selectively activated to communicate reductant to a set of orifices142of the plurality of orifices142. For example, one or more of the valves138may be opened at any given time to cause the reductant to be delivered through the corresponding orifice142of the multipoint injector140via the corresponding reductant delivery line139.

In some embodiments, the reductant distributor130may be located remotely from the multipoint injector140and, therefore the exhaust tube102. This may prevent exposure of the reductant distributor130to high temperature in the vicinity of the exhaust tube102which may cause decomposition of the reductant contained within the reductant distributor130. This prevents crystallization and/or formation of reductant deposits within the reductant distributor130which can clog the valves138. While not shown, in some embodiments, a bypass line or a reductant return line may be provided in the reductant distributor to allow flushing of the reductant from the reductant distributor130and return of the reductant to the reductant storage tank110, for example, when the aftertreatment system100is turned OFF (e.g., due to engine10turning OFF). This may prevent solidification of the reductant within the reductant distributor, for example, when an ambient temperature is below −10 degrees Celsius.

The controller170may be operatively coupled to the reductant insertion assembly112and the reductant distributor130. The controller170may be configured to determine an operating parameter of the exhaust gas and activate the reductant insertion assembly112based on the operating parameter of the exhaust gas, for example, exhaust gas starting to flow through the aftertreatment system100(e.g., due to engine10turning ON), a temperature, flow rate and/or pressure of the exhaust gas, and/or amount of NOx gases included in the exhaust gas. In some embodiments, the controller170may be configured to determine the operating parameter via a signal received from engine10(e.g., an engine ON or OFF signal), from the first sensor103, the second sensor105and/or any other sensor included in the aftertreatment system100(e.g., an exhaust gas temperature, pressure, flow rate, or NOx sensor).

The controller170may be configured to selectively activate (i.e., open) a set of the plurality of valves138so as to allow the reductant to be communicated to a corresponding set of orifices142of the plurality of orifices142. For example, the controller170may be configured to determine an operating parameter of the exhaust gas, and selectively activate the set of the plurality of valves138based on the operating parameter of the exhaust gas.

In some embodiments, the controller170is configured to activate each of the plurality of valves138simultaneously. In other embodiments, the controller170may be configured to activate a first set of the plurality of valves138at a first time point causing the reductant to be inserted through a corresponding first set of orifices142into a first location of the exhaust gas flow path. In other embodiments, the controller170may be configured to activate a second set of the plurality of valves138different than the first set of the plurality of valves138at a second time point causing the reductant to be inserted through a corresponding second set of orifices142into a second location of the exhaust gas flow path different from the first location. The first set of the plurality of valves138are closed at the second time point.

The controller170may be operatively coupled to the components of the aftertreatment system100using any type and any number of wired or wireless connections. For example, a wired connection may include a serial cable, a fiber optic cable, a CAT5 cable, or any other form of wired connection. Wireless connections may include the Internet, Wi-Fi, cellular, radio, Bluetooth, ZigBee, etc. In one embodiment, a controller area network (CAN) bus provides the exchange of signals, information, and/or data. The CAN bus includes any number of wired and wireless connections.

In particular embodiments, the controller170may be included in a control circuitry. For example,FIG. 2is a schematic block diagram of a control circuitry171that comprises the controller170, according to an embodiment. The controller170comprises a processor172, a memory174, or any other computer readable medium, and a communication interface176. Furthermore, the controller170includes an operating parameter determination circuitry174a, a reductant insertion control circuitry174band a reductant distributor control circuitry174c. It should be understood that the controller170shows only one embodiment of the controller170and any other controller capable of performing the operations described herein can be used (e.g., the computing device430).

The processor172can comprise a microprocessor, programmable logic controller (PLC) chip, an ASIC chip, or any other suitable processor. The processor172is in communication with the memory174and configured to execute instructions, algorithms, commands, or otherwise programs stored in the memory174.

The memory174comprises any of the memory and/or storage components discussed herein. For example, memory174may comprise a RAM and/or cache of processor172. The memory174may also comprise one or more storage devices (e.g., hard drives, flash drives, computer readable media, etc.) either local or remote to controller170. The memory174is configured to store look up tables, algorithms, or instructions.

In one configuration, the operating parameter determination circuitry174a, the reductant insertion control circuitry174band the reductant distributor control circuitry174care embodied as machine or computer-readable media (e.g., stored in the memory174) that is executable by a processor, such as the processor172. As described herein and amongst other uses, the machine-readable media (e.g., the memory174) facilitates performance of certain operations to enable reception and transmission of data. For example, the machine-readable media may provide an instruction (e.g., command, etc.) to, e.g., acquire data. In this regard, the machine-readable media may include programmable logic that defines the frequency of acquisition of the data (or, transmission of the data). Thus, the computer readable media may include code, which may be written in any programming language including, but not limited to, Java or the like and any conventional procedural programming languages, such as the “C” programming language or similar programming languages. The computer readable program code may be executed on one processor or multiple remote processors. In the latter scenario, the remote processors may be connected to each other through any type of network (e.g., CAN bus, etc.).

In another configuration, the operating parameter determination circuitry174a, the reductant insertion control circuitry174band the reductant distributor control circuitry174care embodied as hardware units, such as electronic control units. As such, the operating parameter determination circuitry174a, the reductant insertion control circuitry174band the reductant distributor control circuitry174cmay be embodied as one or more circuitry components including, but not limited to, processing circuitry, network interfaces, peripheral devices, input devices, output devices, sensors, etc.

In some embodiments, the operating parameter determination circuitry174a, the reductant insertion control circuitry174band the reductant distributor control circuitry174cmay take the form of one or more analog circuits, electronic circuits (e.g., integrated circuits (IC), discrete circuits, system on a chip (SOCs) circuits, microcontrollers, etc.), telecommunication circuits, hybrid circuits, and any other type of “circuit.” In this regard, the operating parameter determination circuitry174a, the reductant insertion control circuitry174band the reductant distributor control circuitry174cmay include any type of component for accomplishing or facilitating achievement of the operations described herein. For example, a circuit as described herein may include one or more transistors, logic gates (e.g., NAND, AND, NOR, OR, XOR, NOT, XNOR, etc.), resistors, multiplexers, registers, capacitors, inductors, diodes, wiring, and so on.

Thus, the operating parameter determination circuitry174a, the reductant insertion control circuitry174band the reductant distributor control circuitry174cmay also include programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like. In this regard, the operating parameter determination circuitry174a, the reductant insertion control circuitry174band the reductant distributor control circuitry174cmay include one or more memory devices for storing instructions that are executable by the processor(s) of the operating parameter determination circuitry174a, the reductant insertion control circuitry174band the reductant distributor control circuitry174c. The one or more memory devices and processor(s) may have the same definition as provided below with respect to the memory174and the processor172.

In the example shown, the controller170includes the processor172and the memory174. The processor172and the memory174may be structured or configured to execute or implement the instructions, commands, and/or control processes described herein with respect the operating parameter determination circuitry174a, the reductant insertion control circuitry174band the reductant distributor control circuitry174c. Thus, the depicted configuration represents the aforementioned arrangement where the operating parameter determination circuitry174a, the reductant insertion control circuitry174band the reductant distributor control circuitry174care embodied as machine or computer-readable media. However, as mentioned above, this illustration is not meant to be limiting as the present disclosure contemplates other embodiments such as the aforementioned embodiment where the operating parameter determination circuitry174a, the reductant insertion control circuitry174band the reductant distributor control circuitry174c, or at least one circuit of the operating parameter determination circuitry174a, the reductant insertion control circuitry174band the reductant distributor control circuitry174care configured as a hardware unit. All such combinations and variations are intended to fall within the scope of the present disclosure.

The processor172may be implemented as one or more general-purpose processors, an application specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGAs), a digital signal processor (DSP), a group of processing components, or other suitable electronic processing components. In some embodiments, the one or more processors may be shared by multiple circuits (e.g., the operating parameter determination circuitry174a, the reductant insertion control circuitry174band the reductant distributor control circuitry174c) may comprise or otherwise share the same processor which, in some example embodiments, may execute instructions stored, or otherwise accessed, via different areas of memory). Alternatively or additionally, the one or more processors may be structured to perform or otherwise execute certain operations independent of one or more co-processors. In other example embodiments, two or more processors may be coupled via a bus to enable independent, parallel, pipelined, or multi-threaded instruction execution. All such variations are intended to fall within the scope of the present disclosure. The memory174(e.g., RAM, ROM, Flash Memory, hard disk storage, etc.) may store data and/or computer code for facilitating the various processes described herein. The memory174may be communicatively connected to the processor172to provide computer code or instructions to the processor172for executing at least some of the processes described herein. Moreover, the memory174may be or include tangible, non-transient volatile memory or non-volatile memory. Accordingly, the memory174may include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described herein.

The communication interface176may include wireless interfaces (e.g., jacks, antennas, transmitters, receivers, communication interfaces, wire terminals, etc.) for conducting data communications with various systems, devices, or networks. For example, the communication interface176may include an Ethernet card and port for sending and receiving data via an Ethernet-based communications network and/or a Wi-Fi communication interface for communicating with, for example, the first sensor103, the second sensor105, the engine10, the reductant insertion assembly112, the reductant distributor130and/or any other component of the aftertreatment system100. The communication interface176may be structured to communicate via local area networks or wide area networks (e.g., the Internet, etc.) and may use a variety of communications protocols (e.g., IP, LON, Bluetooth, ZigBee, radio, cellular, near field communication, etc.).

The operating parameter determination circuitry174amay be configured to receive an operating condition signal (e.g., from the engine10, the first sensor103, the second sensor105or any other sensors included in the aftertreatment system100) and determine an operating condition of the exhaust gas therefrom (e.g., an exhaust gas temperature, pressure, flow rate and/or amount of NOx gases included in the exhaust gas).

The reductant insertion control circuitry174bis configured to use the operating condition of the exhaust gas to generate a reductant insertion assembly signal configured to activate the reductant insertion assembly112(e.g., turn ON a pump of the reductant insertion assembly112) and/or open a dosing valve of the reductant insertion assembly112, for example, to cause a reductant to flow from the reductant insertion assembly112to the reductant distributor130. For example, the reductant insertion control circuitry174bmay be configured to activate the reductant insertion assembly112in response to the engine10turning ON, which corresponds to commencement of flow of the exhaust gas through the aftertreatment system100, and/or the exhaust gas temperature, pressure, flow rate, and/o amount of NOx gases included in the exhaust gas being equal to or greater than a predetermined threshold. In other embodiments, the reductant insertion control circuitry174bmay be configured to activate the reductant insertion assembly112in response to a volume of ammonia stored in the catalyst152of the SCR system150being less than a predetermined threshold. Similarly, the reductant insertion control circuitry174bmay be configured to deactivate the reductant insertion assembly112(e.g., turn OFF a pump or close the dosing valve of the reductant insertion assembly112) in response to a different operating condition signal (e.g., corresponding to the engine10turning OFF, temperature, pressure, flow rate and/or amount of NOx gases included in the exhaust gas being less than the predetermined threshold, and/or the amount of ammonia stored in the SCR system150being equal to or greater than the predetermined threshold).

The reductant distributor control circuitry174cis configured activate one or more of the plurality of valves138included in the reductant distributor130for inserting the reductant into the exhaust gas flow path via the corresponding orifices142fluidly coupled to the activated valves138. The reductant distributor control circuitry174cmay be configured to selectively activate any suitable combination of the plurality of valves138to provide a desired flow pattern, volume and/or insertion rate of the reductant through the corresponding orifices142. In some embodiments, the reductant distributor control circuitry174cmay be configured to activate each of the plurality of valves138simultaneously. In other embodiments, the reductant distributor control circuitry174cmay be configured to activate a first set of the plurality of valves138at first time point causing the reductant to be inserted through a corresponding first set of orifices142into a first location of the exhaust gas flow path. Furthermore, the reductant distributor control circuitry174cmay be further configured to activate a second set of the plurality of valves138different than the first set of valves138at a second time point causing the reductant to be inserted through a corresponding second set of orifices142into a second location of the exhaust gas flow path different than the first location.

FIGS. 3A-3Bis a perspective view of a reductant distributor230, according to an embodiment. The reductant distributor230comprises a reductant distributor housing232defining a plurality of outlets236on a first side wall thereof. While shown as including 9 outlets236, in various embodiments, the reductant distributor230may include any number of outlets236(e.g., 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or even more). The number of outlets236correspond to a number of orifices provided in an associated multipoint injector (e.g., the multipoint injector140,240). Furthermore, the plurality of outlets236may all be defined on a single sidewall (e.g., the first side wall), or distributed among various sidewall of the reductant distributor housing232. A plurality of valves (not shown) may be disposed within the internal volume of the reductant distributor housing232, each of the plurality of valves associated with a respective outlet236of the reductant distributor230.

An inlet231is provided on a second sidewall of the reductant distributor housing232opposite the first sidewall, but may be provided on any other sidewall of the reductant distributor housing232. The inlet231is configured to be coupled to a reductant insertion assembly (e.g., the reductant insertion assembly112) via a reductant receiving line (e.g., the reductant receiving line114). The reductant distributor230also includes an electrical connector237configured to communicatively couple the reductant distributor230to a controller (e.g., the controller170) which may be configured to selectively activate one or more of the plurality of valves238, as previously described herein.

FIG. 4is a side perspective view of an exhaust tube202with a multipoint injector240coupled thereto.FIG. 5is a side perspective view of the multipoint injector240uncoupled from the exhaust tube202. The exhaust tube202comprises an exhaust tube first portion206positioned upstream of the multipoint injector240and an exhaust tube second portion208positioned downstream of the multipoint injector240. The multipoint injector240is coupled to the exhaust tube first and second portions206and208such that the multipoint injector240defines a portion of the exhaust gas flow path.

The multipoint injector240comprises an injector body241having a circumferential wall243. The injector body241may be formed from any suitable heat resistant material, for example, metals or ceramics. WhileFIGS. 4-5show the injector body241having a circular cross-section, in other embodiments, the injector body241may have a non-circular cross-section, for example, square, rectangular, oval, elliptical, or asymmetric corresponding to a cross-section of the exhaust tube202or otherwise an exhaust tube (e.g., the exhaust tube102).

The multipoint injector240defines a channel244therethrough which forms the portion of the exhaust gas flow path, such that the exhaust gas flows through the channel244as it flows through the exhaust tube202towards downstream aftertreatment components, for example, an SCR system (e.g., the SCR system150). A plurality of flanges245are formed at axial ends of the injector body241and extend radially outwards from the injector body241. The flanges245are coupled to corresponding portions206and208of the exhaust tube202via coupling bands260. For example, ends of the exhaust tube first and second portions206and208may be positioned around a portion of the corresponding flanges245and clamped thereon via the coupling bands260. The coupling band260includes a winching mechanism (e.g., a lead screw and nut) for clamping the coupling bands260around the flanges245. In this manner, the multipoint injector240may be removably coupled to the exhaust tube202, for example, to facilitate replacement of the multipoint injector240. This facilitates replacement of the multipoint injector240(e.g., due to malfunction) without having to replace the exhaust tube202. While not shown, a sealing member may positioned between the ends of the exhaust tube first and second portions206and208, and the flanges245so as prevent leakage of exhaust gas at the interface.

Referring also now toFIGS. 6A-6C, a plurality of orifices242extend through the circumferential wall243to the channel244. The orifices242may have a diameter in a range of 0.40 mm to 0.55 mm. In some embodiments, each of the plurality of orifices242may have the same diameter. In other embodiments, at least some of the orifices242may have a different diameter from the other orifices242. A cavity247is defined around each orifice242and is configured to receive a fluid connector246. In some embodiments, threads may be defined on the sidewall of the cavity247and structured to engage mating threads defined on the fluid connector246to allow coupling of the fluid connector246thereto. Reductant delivery lines (e.g., fluidic tubes or hoses) may fluidly couple outlets of a reductant distributor (e.g., the reductant distributor230) to a corresponding fluid connector246for delivering reductant to the corresponding orifice242of the plurality of orifices242.

As shown inFIG. 6C, at least some of the orifices242are oriented at an angle α with respect to a flow axis FA of the exhaust gas. In some embodiments, each of the orifices242may be oriented at the same angle with respect to the flow axis FA. In other embodiments, one or more of the orifices242may be oriented at different angles with respect to the flow axis FA relative to the other orifices242.

FIG. 7Ais a front view andFIG. 7Bis a side cross-section view of a portion of the exhaust tube202ofFIG. 4that includes the multipoint injector240showing the reductant being inserted simultaneously through each of the plurality of orifices242of the multipoint injector240into the channel244defining a portion of the exhaust gas flow path. The reductant spray cones inserted from corresponding orifices242overlap with at least one of the other reductant spray cones. This causes the reductant droplets to randomly collide with each other increasing turbulence, which enhances mixing with exhaust gas and reduces reductant deposits.

Since the reductant is inserted in to the channel244, any impingement of the reductant streams is on an inner surface of the circumferential wall243that forms the channel244instead of on the inner surface of the exhaust tube202. Thus any reductant deposit formation is substantially limited to the circumferential wall243. Therefore, any maintenance performed to remove reductant deposits may be limited to multipoint injector240which can easily be removed and reinstalled on the exhaust tube202. This reduces maintenance costs.

In some embodiments, the reductant distributor230or any other reductant distributor may be used to selectively provide reductant to a set of orifices242of the plurality of orifices242. For example, in a first configuration shown inFIGS. 8A-8B, reductant is provided through a first set of outlets236a/d/gof the reductant distributor230to a corresponding first set of fluid connectors246a/d/gfor inserting reductant through the respective orifices242. In a second configuration shown inFIGS. 9A-9B, the reductant is provided through a second set of outlets236b/e/hto a corresponding second set of fluid connectors246b/e/hfor inserting reductant through the respective orifices242, thereby reorienting the reductant spray pattern clockwise. Similarly, in a third configuration shown inFIGS. 10A-10B, the reductant is provided through a third set of outlets236c/f/ito a corresponding third set of fluid connectors246c/f/ifor inserting reductant through the respective orifices242, thereby further reorienting the reductant spray pattern clockwise, and so on.

FIGS. 11A-11Dshow various other operational configurations of inserting the reductant through the multipoint injector240.FIG. 11Ashows an operational configuration in which reductant is inserted through five adjacent orifices242and sequentially cycled clockwise.FIG. 11Bshows another configuration in which reductant is inserted through a different set of five orifices242and cycled clockwise.FIG. 11Cshows yet another configuration in which reductant is inserted through six orifices242and cycled clockwise. Three of the orifices242are located on one side of the circumferential wall243and the remaining three orifices242are located on opposite side of the circumferential wall243. FIG.11D shows still another configuration in which the reductant is inserted through four orifices242and cycled clockwise.

FIG. 12is a schematic flow diagram of an example method300for inserting a reductant at a plurality of locations in an aftertreatment system (e.g., the aftertreatment system100) via a multipoint injector (e.g., the multipoint injector140,240) coupled to an exhaust tube (e.g., the exhaust tube102,202) of the aftertreatment system.

The method300comprises determining an operating parameter of the exhaust gas, at302. For example, the operating parameter determination circuitry174amay receive an operating parameter signals from the engine10, the first sensor103, the second sensor105or any other sensor included in the aftertreatment system100and determine the operating parameter of the exhaust gas (e.g., an amount of NOx gases in the exhaust, a temperature of the exhaust gas, a flow rate and/or pressure of the exhaust gas) therefrom. The operating parameter determination circuitry174amay determine if the reductant is to be inserted into the aftertreatment system100, a flow rate and/or a volume of the exhaust gas to be inserted into the aftertreatment system100.

At304, a reductant is inserted through at least a portion of the plurality of orifices into a flow path of an exhaust gas flowing through the exhaust tube based on the operating parameter. For example, the reductant insertion control circuitry174bmay activate the reductant insertion assembly112, and the reductant distributor control circuitry174cmay activate at least a portion of the valves138to communicate a reductant through a corresponding portion of the outlets136,236to the respective orifices142,242to which these outlets136,236are coupled based on the operating parameter.

In some embodiments, the method300may comprise inserting the reductant through each of the plurality of orifices, at306. For example, the reductant distributor control circuitry174cmay open each of the valves138of the reductant distributor causing the reductant to be communicated through each of the orifices142,242into the flow path of the exhaust gas.

In some embodiment, the method300also comprises inserting the reductant through a first set of orifices of the plurality of orifices at a first time point causing the reductant to be inserted into a first location of the exhaust gas flow path, at308. For example, the reductant distributor control circuitry174cmay be configured to open a first set of valves138of the reductant distributor130,230causing the reductant to be inserted through a corresponding set of orifices142/242into the flow path of the exhaust gas, as previously described herein.

Furthermore, at310, the reductant is inserted through a second set of orifices of the plurality of orifices different than the first set of orifices at a second time point causing the reductant to be inserted into a second location of the exhaust gas flow path different than the first location. For example, the reductant distributor control circuitry174cmay close the first set of valves138and open a second set of valves, different than the first set causing the reductant to be inserted through a corresponding second set of orifices142,242into the exhaust tube102(e.g., at the exhaust tube102,202). In this manner, the reductant impacts different locations of the circumferential wall243defined by the multipoint injector140,240during different insertion cycles rather than the same location on every cycle which reduces reductant deposits and enhances mixing of the reductant with the exhaust gas.

In some embodiments, the controller170, the control circuitry171or any of the controllers described herein can be a system computer of an apparatus or system which includes the multipoint injector140and optionally, the reductant distributor130. For example,FIG. 13is a block diagram of a computing device430in accordance with an illustrative implementation. The computing device430can be used to perform any of the methods or the processes described herein, for example the method300. The computing device430includes a bus432or other communication component for communicating information. The computing device430can also include one or more processors434or processing circuits coupled to the bus for processing information.

The computing device430also includes main memory436, such as a random access memory (RAM) or other dynamic storage device, coupled to the bus432for storing information, and instructions to be executed by the processor434. Main memory436can also be used for storing position information, temporary variables, or other intermediate information during execution of instructions by the processor434. The computing device430may further include a read only memory (ROM)438or other static storage device coupled to the bus432for storing static information and instructions for the processor434. A storage device440, such as a solid-state device, magnetic disk or optical disk, is coupled to the bus440for persistently storing information and instructions.

The computing device430may be coupled via the bus432to a display435, such as a liquid crystal display, or active matrix display, for displaying information to a user. An input device442, such as a keyboard or alphanumeric pad, may be coupled to the bus432for communicating information and command selections to the processor434. In another implementation, the input device442has a touch screen display444.

According to various implementations, the processes and methods described herein can be implemented by the computing device430in response to the processor434executing an arrangement of instructions contained in main memory436(e.g., the operations of the method300). Such instructions can be read into main memory436from another non-transitory computer-readable medium, such as the storage device440. Execution of the arrangement of instructions contained in main memory436causes the computing device430to perform the illustrative processes described herein. One or more processors in a multi-processing arrangement may also be employed to execute the instructions contained in main memory436. In alternative implementations, hard-wired circuitry may be used in place of or in combination with software instructions to effect illustrative implementations. Thus, implementations are not limited to any specific combination of hardware circuitry and software.

It should be noted that the term “example” as used herein to describe various embodiments is intended to indicate that such embodiments are possible examples, representations, and/or illustrations of possible embodiments (and such term is not intended to connote that such embodiments are necessarily extraordinary or superlative examples).

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