Patent Application
20190195106
The present disclosure relates generally to aftertreatment systems for use with internal combustion (IC) engines.
Exhaust aftertreatment systems are used to receive and treat exhaust gas generated by IC engines. Generally, exhaust gas aftertreatment systems comprise 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 comprise a selective catalytic reduction (SCR) system, including a catalyst formulated to convert NOx (NO and NO2 in 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 fluidly communicated to the catalyst included in the SCR system to decompose substantially all of the NOx gases into relatively harmless byproducts that are expelled out of the aftertreatment system.
Aftertreatment systems generally include a reductant insertion assembly for inserting a reductant into the SCR system. Some reductant insertion assemblies use air provided by an air supply system to assist in insertion of the reductant into the SCR system, i.e., provide air-assisted insertion of the reductant. Such air supply systems generally include a compressor and an external air source (e.g., an air tank) to provide air-assisted insertion of the reductant. Furthermore, such air supply systems may also require a dedicated energy source, a filtration system, and/or an oil separation system. These requirements increase the complexity of such reductant insertion assemblies and therefore increase manufacturing and maintenance costs.
Embodiments described herein relate generally to systems and methods for providing air-assisted reductant insertion in an aftertreatment system, and in particular to a reductant insertion assembly that includes an injector positioned on a SCR system for inserting a reductant therein. A portion of compressed air from an outlet of a compressor included in a turbocharger of the aftertreatment system is rerouted to the injector and used in air-assisted insertion of the reductant into the SCR system.
In one embodiment, an aftertreatment system structured to decompose constituents of an exhaust produced by an engine having a turbocharger including a turbine and a compressor coupled thereto, includes: a selective catalytic reduction system; an injector fluidly coupled to the selective catalytic reduction system and structured to selectively insert a reductant into the selective catalytic reduction system an intake conduit fluidly coupled to a compressor outlet of the compressor and structured to deliver a compressed air from the compressor to the engine; and an air delivery line fluidly coupling the intake conduit to the injector, the air delivery line being structured to deliver a portion of the compressed air to the injector so as to facilitate air-assisted insertion of the reductant by the injector.
In another embodiment, an aftertreatment system for an internal combustion engine includes a turbocharger, an intake conduit, an intake manifold, an air delivery line, and a housing. The turbocharger includes a compressor and a turbine. The compressor is configured to receive air from an air source. The turbine is configured to receive exhaust from the internal combustion engine. The intake conduit is configured to receive compressed air from compressor. The intake manifold is configured to receive a first portion of the compressed air from the intake conduit and to provide the first portion of the compressed air to the internal combustion engine. The air delivery line is configured to receive a second portion of the compressed air from the intake conduit separate from the intake manifold. The housing is configured to receive the second portion of compressed air from the air delivery line and to receive the exhaust from the turbine.
In yet another embodiment, an aftertreatment system for an internal combustion engine having a turbocharger with a compressor and a turbine, includes an intake conduit, an air delivery line, and a housing. The intake conduit is configured to receive compressed air. The air delivery line is coupled to the intake conduit and structured such that a first portion of the compressed air bypasses the air delivery line and a second portion of the compressed air is diverted into the air delivery line. The housing is structured to receive the second portion of compressed air from the air delivery line and to separately receive exhaust.
It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the subject matter disclosed herein.
The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several implementations in accordance with the disclosure and are therefore not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through use of the accompanying drawings.
Reference is made to the accompanying drawings throughout the following detailed description. In the drawings, similar symbols typically identify similar components unless context dictates otherwise. The illustrative implementations described in the detailed description, drawings, and claims are not meant to be limiting. Other implementations may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here. It will be readily understood that the aspects of the present disclosure, as generally described herein and illustrated in the figures, can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and made part of this disclosure.
Embodiments described herein relate generally to systems and methods for providing air-assisted reductant insertion in an aftertreatment system, and in particular to a reductant insertion assembly that includes an injector positioned on a SCR system for inserting a reductant therein. A portion of compressed air from an outlet of a compressor included in a turbocharger of the aftertreatment system is rerouted to the injector and used in air-assisted insertion of the reductant into the SCR system.
Aftertreatment systems generally include a reductant insertion assembly for inserting a reductant into the SCR system. Some reductant insertion assemblies use air provided by an air supply system to assist in insertion of the reductant into the SCR system, i.e., provide air-assisted insertion of the reductant. For example, air may be mixed with the reductant, or air pulses may be used to insert the reductant. Such air supply systems generally include a compressor and an external air source (e.g., an air tank) to provide air-assisted insertion of the reductant. Furthermore, such air supply systems may also require a dedicated energy source, a filtration and/or an oil separation system. This increases the complexity of such reductant insertion assemblies and increases manufacturing, as well as maintenance costs.
Various embodiments of the systems and methods described herein may provide benefits including, for example: (1) using a portion of compressed air from an outlet of a compressor included in an aftertreatment system, thereby eliminating the use of a dedicated air source or supply; (2) eliminating the use of a dedicated energy source, filtration and/or oil separation system; and (3) reducing energy consumption, manufacturing costs as well as maintenance costs.
The engine 10 may include a diesel engine, a gasoline engine, a biodiesel engine, a natural gas engine, a dual fuel engine, or any other suitable engine that burns a fuel to produce energy and generates an exhaust gas. The engine 10 comprises a plurality of engine cylinders 12. While shown as including four engine cylinders 12, in other embodiments, the engine 10 may include any number of engine cylinders, for example 6, 8, 10, 12, 14, 16, 18, 20 or even more.
An intake manifold 20 is fluidly coupled to the engine 10 via a plurality of intake manifold conduits 22. The intake manifold 20 is structured to receive air from a compressor 134 of the turbocharger 130, described below in further detail, and communicate the air to each of the engine cylinders 12 via the corresponding intake manifold conduit 22. Furthermore, an exhaust manifold 30 is fluidly coupled to the engine 10 via a plurality of exhaust manifold conduits 32. The exhaust manifold 30 is structured to receive the exhaust gas from each of the engine cylinders 12 via the corresponding exhaust manifold conduit 32 and communicate the exhaust gas to the SCR system 150 via the turbocharger 130.
The SCR system 150 is positioned downstream of the turbocharger 130 and comprises a housing 152 defining an internal volume within which at least one catalyst 154 is positioned. The housing 152 may be formed from a rigid, heat-resistant and corrosion-resistant material, for example stainless steel, iron, aluminum, metal, ceramic, or any other suitable material. The housing 152 may have any suitable cross-section, for example circular, square, rectangular, oval, elliptical, polygonal, or any other suitable shape.
In some embodiments, the SCR system 150 may comprise a selective catalytic reduction filter (SCRF) system, 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 through the aftertreatment system 100 in the presence of a reductant, as described herein.
Although
An inlet conduit 151 is fluidly coupled to an inlet of the housing 152 and structured to receive exhaust gas from the engine 10. The inlet conduit 151 communicates the exhaust gas to an internal volume defined by the housing 152. Furthermore, an outlet conduit 153 may be coupled to an outlet of the housing 152 and structured to expel treated exhaust gas into the environment. One or more sensors may be positioned in the inlet conduit 151. Such sensors may include a NOx sensor, for example a physical or virtual NOx sensor, configured to determine an amount of NOx gases included in the exhaust gas being emitted by the engine 10.
In other embodiments, an oxygen sensor, an ammonia sensor, a temperature sensor, a pressure sensor, or any other sensor may also be positioned in the inlet conduit 151 so as to determine one or more operational parameters of the exhaust gas flowing through the aftertreatment system 100. One or more sensors may also be positioned in the outlet conduit 153. The one or more sensors may comprise a second NOx sensor configured to determine an amount of NOx gases expelled into the environment after passing through the SCR system 150, and/or a particulate matter sensor.
The catalyst 154 is formulated to decompose constituents of an exhaust gas, for example NOx gases, flowing through the aftertreatment system 100. The catalyst 154 is formulated to selectively decompose constituents of the exhaust gas. Any suitable catalyst can be used such as, for example, platinum, palladium, rhodium, cerium, iron, manganese, copper, vanadium based catalyst, any other suitable catalyst, or a combination thereof. The catalyst 154 can 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 catalyst 154. Such washcoat materials may comprise, for example, aluminum oxide, titanium dioxide, silicon dioxide, any other suitable washcoat material, or a combination thereof. The exhaust gas (e.g., diesel exhaust gas) can flow over and/or about the catalyst 154 such that any NOx gases included in the exhaust gas are further reduced to yield an exhaust gas which is substantially free of NOx gases.
An injector 122 may be positioned on a sidewall of housing 152 and is in fluid communication with the internal volume of the housing 152, for example via a reductant insertion port defined on a sidewall of the housing 152. In various embodiments, the injector 122 may comprise a dosing lance. The injector 122 is configured to selectively insert a reductant into the internal volume defined by the housing 152. The injector 122 may also include a nozzle 124 structured to shear the reductant into droplets so as to deliver the reductant as a mist, a stream, a jet or as a conical spray cone into the SCR system 150. Furthermore, the injector 122 may be configured to insert the reductant droplets as a steady state stream, or in a pulsed or transient sequence.
Furthermore, the injector 122 is structured to receive air, as described herein so as to provide air-assisted insertion of the reductant into the SCR system 150. For example, the injector 122 may 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, for example from the compressor 134 as described herein, so as to deliver a combined flow of the air and the reductant to the SCR system 150 through the nozzle 124.
The aftertreatment system 100 may also include a reductant storage tank 110 and a reductant insertion assembly 120. The reductant storage tank 110 is structured to store the reductant. The reductant is formulated to facilitate decomposition of the constituents of the exhaust gas (e.g., NOx gases included in the exhaust gas). Any suitable reductant can be used. In some embodiments, the exhaust gas comprises a diesel exhaust gas and the reductant comprises a diesel exhaust fluid. For example, the diesel exhaust fluid may comprise urea, an aqueous solution of urea, or any other fluid that comprises ammonia, by-products, or any other suitable diesel exhaust fluid (e.g., the diesel exhaust fluid marketed under the name) ADBLUE®). In particular embodiments, the reductant comprises an aqueous urea solution having a particular ratio of urea to water. For example, the reductant may comprise an aqueous urea solution including 32.5% by volume of urea and 67.5% by volume of deionized water. In other embodiments, the reductant may include 40% by volume of urea and 60% by volume of deionized water.
A reductant insertion assembly 120 is fluidly coupled to the reductant storage tank 110. The reductant insertion assembly 120 is configured to selectively provide the reductant to the injector 122 from the reductant storage tank 110. The reductant insertion assembly 120 may comprise one or more pumps having filter screens (e.g., to prevent solid particles of the reductant or contaminants from flowing into the pump) and/or valves (e.g., check valves) positioned upstream thereof to receive reductant from the reductant storage tank 110. In some embodiments, the pump may comprise a diaphragm pump but any other suitable pump may be used such as, for example, a centrifugal pump, a suction pump, etc.
The pump may be configured to pressurize the reductant so as to provide the reductant to the injector 122 at a predetermined pressure. Screens, check valves, pulsation dampers, or other structures may also be positioned downstream of the pump to provide the reductant to the injector 122. In various embodiments, the reductant insertion assembly 120 may also comprise a bypass line structured to provide a return path of the reductant from the pump to the reductant storage tank 110
A valve (e.g., an orifice valve) may be provided in the bypass line. The valve may be structured to allow the reductant to pass therethrough to the reductant storage tank 110 if an operating pressure of the reductant generated by the pump exceeds a predetermined pressure so as to prevent over pressurizing of the pump, the reductant delivery lines, or other components of the reductant insertion assembly 120. In some embodiments, the bypass line may be configured to allow the return of the reductant to the reductant storage tank 110 during purging of the reductant insertion assembly 120 (e.g., after the engine 10 is shut off).
The turbocharger 130 is positioned upstream of the SCR system 150 and downstream of the exhaust manifold 30. The turbocharger 130 comprises a turbine 132 and the compressor 134 operably coupled to the turbine 132 via a shaft 136. A turbine inlet 133 of the turbine 132 is fluidly coupled to the exhaust manifold 30 via an exhaust conduit 131, and structured to receive the exhaust gas therefrom. The exhaust gas drives the turbine 132 and thereby the compressor 134 via the shaft 136. The inlet conduit 151 is also fluidly coupled to the turbine 132 and communicates the exhaust gas therefrom to the SCR system 150.
The compressor 134 is fluidly coupled to an air inlet conduit 162 and configured to receive air therefrom. An air filter 160 may be positioned upstream of the air inlet conduit 162 and structured to remove particles such as, for example dust, soot, carbon, inorganic particles, etc. from the air communicated to the compressor 134. Driving of the compressor 134 by the turbine 132 may generate negative pressure in the air inlet conduit 162 which draws air into the compressor 134. The compressor 134 is structured to compress the air so as to produce compressed air at a first pressure. The first pressure may be less than 1 bar.
An intake conduit 138 is fluidly coupled to a compressor outlet 135 of the compressor 134 and structured to deliver the compressed air from the compressor 134 to the engine 10 via the intake manifold 20. An air delivery line 144 fluidly couples the intake conduit 138 to the injector 122. The air delivery line 144 is structured to deliver a portion of the compressed air to the injector 122 so as to facilitate air-assisted insertion of the reductant by the injector 122 into the SCR system 150. Expanding further, the air delivery line 144 includes a sideline (e.g., a small tube, hose or conduit) which draws the first portion of the compressed air from the intake conduit 138 and delivers to the injector 122.
In various embodiments, the portion of the compressed air may have a volume in a range of 0.01-8% (e.g., 0.01%, 0.02%, 1%, 1.1%, 7.9%, 7.99%, or 8% inclusive of all ranges and values therebetween) of a total volume of the compressed air flowing through the intake conduit 138. In one embodiment, where the first pressure is greater than 2.5 bar, the portion of the compressed air may have a volume of less than 1% of the total volume of the compressed air flowing through the intake conduit 138.
In some embodiments, the portion of the compressed air may have a volume in a range of 0.5-8% (e.g., 0.5%, 1%, 1.5%, 7%, 7.5%, or 8% inclusive of all ranges and values therebetween) of a total volume of the compressed air flowing through the intake conduit 138. In some embodiments, the portion of the compressed air may have a volume in a range of 4-8% (e.g., 4%, 5%, 6%, 7%, or 8% inclusive of all ranges and values therebetween) of the total volume of the compressed air flowing through the intake conduit 138. In some embodiments, the air delivery line 144 may be fluidly coupled to any portion of the turbocharger 130, for example the turbine 132 (e.g., the turbine inlet 133 of the turbine 132) or the compressor 132 and configured to receive the air therefrom.
In some embodiments, the air delivery line 144 delivers the compressed air at the first pressure to the injector 122. In such embodiments, the first pressure may be sufficient for the injector 122 to provide air-assisted reductant insertion into the SCR system 150. Furthermore, the nozzle 124 may be structured to shear the reductant into reductant droplets using the compressed air at the first pressure.
In other embodiments, a booster pump 146 (e.g., a positive displacement pump, a centrifugal pump, a rotary lobe pump, a progressive cavity pump, a rotary gear pump, a piston pump, a diaphragm pump, a screw pump, a gear pump, a hydraulic pump, etc.) may be positioned in the air delivery line 144 upstream of the injector 122. The booster pump 146 may be configured to pressurize the portion of the compressed air so as to generate pressurized air having a second pressure greater than the first pressure, and deliver the pressurized air to the injector 122. In particular embodiments, the second pressure may be in a range of 1-3 bar (e.g., 1 bar, 1.5 bar, 2 bar, 2.5 bar or 3 bar inclusive of all ranges and values therebetween), and may correspond to a designed pressure of the injector 122. Moreover, the nozzle 124 may be structured to shear the reductant into reductant droplets using the pressurized air at the second pressure.
In still other embodiments, a flow valve 148 may be positioned in the air delivery line 144 upstream of the booster pump 146. The flow valve 148 may include a check valve, a butterfly valve, a disc valve, a clapper valve, a diaphragm valve or any other suitable valve structured to control a flow rate of the portion of the compressed air to the injector 122.
In this manner, the aftertreatment system 100 uses a portion of the compressed air provided by the compressor 134 of the turbocharger 130 for air-assisted insertion of the reductant through the injector 122 into the SCR system 150. This eliminates the use of a separate air supply system for providing air to the injector 122, thereby reducing energy consumption, manufacturing costs, and/or maintenance costs.
While
The method 200 comprises communicating an exhaust gas from an exhaust manifold of an engine to the turbine so as to drive the compressor, at 202. For example, the exhaust gas is communicated from the exhaust manifold 30 fluidly coupled to the engine 10, to the turbine 132 via the exhaust conduit 131. The exhaust gas drives the turbine 132 and thereby the compressor 134 via the shaft 136. The compressor 134 may receive air from the air inlet conduit 162 (e.g., after passing through the air filter 160) and compress the air so as to generate compressed air.
The compressed air is communicated from the compressor to an intake manifold of the engine via an intake conduit, at 204. For example, the compressed air from the compressor 134 is communicated to the intake manifold 20 via the intake conduit 138. A portion of the compressed air is communicated to an air delivery line fluidly coupling the intake conduit to an injector fluidly coupled to the SCR system, at 206. For example, the portion of the compressed air is communicated to the air delivery line 144 fluidly coupled at one end to the intake conduit 138, and at an opposite end to the injector 122.
In some embodiments, the method 200 also includes pressurizing the portion of the compressed air so as to produce pressurized air, at 208. For example, the booster pump 146 may be positioned in the air delivery line 144, and structured to pressurize the portion of the compressed air so as to generate the pressurized air. The pressurized air is delivered to the injector 122 via the air delivery line 144. A reductant mixed with the portion of the compressed air is communicated into the SCR system via the injector, at 210. For example, the injector 122 inserts the reductant mixed with the portion of the compressed air or the pressurized air into the SCR system 150, thereby providing air-assisted insertion of the reductant into the SCR system 150.
A ⅜ inch air delivery line was used to fluidly couple an air intake conduit to an injector. A booster pump was used to pump compressed air at various air pressures to the injector via the air delivery line. The injector included a nozzle having a SU46 body and a SU29 orifice. Table 1 shows results of air flow and reductant insertion rates at various air pressures, as well as the profile of a DEF spray produced by the nozzle.
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).
The terms “coupled” and the like as used herein mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another.
It is important to note that the construction and arrangement of the various exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements; values of parameters, mounting arrangements; use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. Additionally, it should be understood that features from one embodiment disclosed herein may be combined with features of other embodiments disclosed herein as one of ordinary skill in the art would understand. Other substitutions, modifications, changes, and omissions may also be made in the design, operating conditions, and arrangement of the various exemplary embodiments without departing from the scope of the present application.
While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any embodiments or of what may be claimed, but rather as descriptions of features specific to particular implementations of particular embodiments. Certain features described in this specification in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.
This application claims the benefit of and priority to U.S. Provisional Patent Application No. 62/609,712, filed Dec. 22, 2017, the entire disclosure of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62609712 | Dec 2017 | US |
