CN110500161A - Selective catalytic reduction device control - Google Patents

Selective catalytic reduction device control Download PDF

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Publication number
CN110500161A
CN110500161A CN201910366148.XA CN201910366148A CN110500161A CN 110500161 A CN110500161 A CN 110500161A CN 201910366148 A CN201910366148 A CN 201910366148A CN 110500161 A CN110500161 A CN 110500161A
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China
Prior art keywords
scr device
amount
scr
reducing agent
exit
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Pending
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CN201910366148.XA
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Chinese (zh)
Inventor
M·卡米哥亚
G·比内蒂
C·I·霍约斯韦拉斯科
G·马扎拉博洛尼亚
A·贝伯拉德
D·贝尔纳迪尼
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GM Global Technology Operations LLC
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GM Global Technology Operations LLC
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Publication of CN110500161A publication Critical patent/CN110500161A/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/105—General auxiliary catalysts, e.g. upstream or downstream of the main catalyst
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
    • F01N13/0093—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series the purifying devices are of the same type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F01N3/208—Control of selective catalytic reduction [SCR], e.g. dosing of reducing agent
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/02—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor
    • F01N2560/026—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor for measuring or detecting NOx
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/12—Other sensor principles, e.g. using electro conductivity of substrate or radio frequency
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2570/00—Exhaust treating apparatus eliminating, absorbing or adsorbing specific elements or compounds
    • F01N2570/14—Nitrogen oxides
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/14—Arrangements for the supply of substances, e.g. conduits
    • F01N2610/1453—Sprayers or atomisers; Arrangement thereof in the exhaust apparatus
    • F01N2610/146—Control thereof, e.g. control of injectors or injection valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/04—Methods of control or diagnosing
    • F01N2900/0406—Methods of control or diagnosing using a model with a division of the catalyst or filter in several cells
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/04—Methods of control or diagnosing
    • F01N2900/0414—Methods of control or diagnosing using a state observer
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/06—Parameters used for exhaust control or diagnosing
    • F01N2900/14—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust gas
    • F01N2900/1402—Exhaust gas composition
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/06—Parameters used for exhaust control or diagnosing
    • F01N2900/16—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust apparatus, e.g. particulate filter or catalyst
    • F01N2900/1616—NH3-slip from catalyst
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/06—Parameters used for exhaust control or diagnosing
    • F01N2900/16—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust apparatus, e.g. particulate filter or catalyst
    • F01N2900/1622—Catalyst reducing agent absorption capacity or consumption amount
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/06—Parameters used for exhaust control or diagnosing
    • F01N2900/18—Parameters used for exhaust control or diagnosing said parameters being related to the system for adding a substance into the exhaust
    • F01N2900/1806—Properties of reducing agent or dosing system
    • F01N2900/1821—Injector parameters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Materials Engineering (AREA)
  • Exhaust Gas After Treatment (AREA)

Abstract

Technical solution described herein includes the emission control systems for handling the exhaust in the motor vehicles for including internal combustion engine.Emission control systems include System design based on model device, are injected into exhaust with controlling reducing agent.Control the NO that reducing agent injection includes the exit for determining the first SCR device and the exit of the second SCR devicexAmount and NH3Amount.Control further includes the amount of the reducing agent to be injected of calculating to maintain the NH in the exit of the first SCR device3Amount and NOxAmount between the first estimated rate, and maintain the second SCR device exit NH3Amount and NOxAmount between the second estimated rate.In addition, control includes sending by the received order of reducing agent syringe with the reducing agent of injection calculation amount.

Description

Selective catalytic reduction device control
Introduction
This disclosure relates to be used for the exhaust system of internal combustion engine, and relate more specifically to using selective catalytic reduction (SCR) device is used for the exhaust system of emission control.
Exhaust from internal combustion engine, especially diesel engine discharge is the non-homogeneous mixture comprising gaseous effluent, example Such as carbon monoxide (" CO "), unburned hydrocarbon (" HC ") and nitrogen oxides (" NOx") and composition particulate matter The cohesion phase material (liquid and solid) of (" PM ").After being generally arranged at the catalyst component conduct in catalyst carrier or matrix A part of processing system is provided in engine exhaust system, converts some or all in these exhaust gas compositions to non- The exhaust gas composition of control.
Exhaust-gas treatment system generally includes selective catalytic reduction (SCR) device.SCR device includes substrate, is set on substrate SCR catalyst is equipped with to reduce the NO in exhaustxAmount.Typical exhaust-gas treatment system further includes reducing agent transportation system, Inject reducing agent, such as ammonia (NH3), urea ((NH2)2CO etc.).SCR device utilizes NH3To restore NOx.For example, when appropriate By suitable NH under heat condition3When injecting SCR device, NH3In the presence of SCR catalyst with NOxReaction is to reduce NOxDischarge.Such as Fruit NH3Injection rate is too high, then there are excess of ammonia in exhaust, and ammonia (NH3) may be skidded off from SCR.On the other hand, such as Ammonia in fruit exhaust is very few, then SCRNOxTransformation efficiency reduces.
Summary of the invention
It is a kind of for handling the discharge control of the exhaust of the internal combustion engine in motor vehicles according to one or more embodiments System processed includes reducing agent syringe.Emission control systems further include first choice catalysis reduction (SCR) device.Emission control System further includes the second SCR device.Emission control systems further include controller, are injected into exhaust with controlling reducing agent.Reduction The control of agent injection includes the NO for determining the exit of the first SCR devicexAmount and NH3Amount.The control of reducing agent injection is also wrapped Include the NO for determining the exit of the second SCR devicexAmount and NH3Amount.The control of reducing agent injection further includes calculating to be injected The amount of reducing agent is to maintain the NH in the exit of the first SCR device3Amount and NOxAmount between the first estimated rate, and tie up Hold the NH in the exit of the second SCR device3Amount and NOxAmount between the second estimated rate, to ensure selective catalytic reduction The optimum operation of system, the first SCR device and the second SCR device.The control of reducing agent injection further includes sending to be infused by reducing agent The received order of emitter is with the reducing agent of injection calculation amount.
In one or more examples, the NH in the exit of the first SCR device is determined3Amount be based on calculate the first SCR dress The NH for the first estimation set3Storage is horizontal, and also based in the inlet of the first SCR device reception NOxMeasurement.At one or In multiple examples, the NH in the exit of the second SCR device is determined3Amount based on calculate the second SCR device second estimation NH3 The NH in the exit of storage level and the first SCR device3Amount.Determine the NH in the exit of the second SCR device3Amount also base In in the exit of the first SCR device reception NOxMeasurement.In one or more examples, the first SCR device is SCR filter. In one or more examples, the second SCR device is SCR device under floor.In one or more examples, reducing agent is calculated Amount includes estimating the outlet of the second SCR device based on including the combined operation model of the first SCR device and the second SCR device The NH at place3Amount and NOxAmount.
It is a kind of that exhaust being executed by the exhaust system of the exhaust of engine exhaust for handling according to one or more embodiments Selective catalytic reduction (SCR).Exhaust system includes the first SCR device and controller, is injected into exhaust to control reducing agent In.The control of reducing agent injection includes determining whether exhaust system includes the second SCR device.In response to only including that the first SCR is filled The exhaust system set, the control of reducing agent injection include that the first model based on the first SCR device calculates the reducing agent to be injected Amount, the first model estimate the first SCR device at the first NH3Storage is horizontal.In response to the exhaust system including the second SCR device System, the control of reducing agent injection include the combination of the second model of the first model based on the first SCR device and the second SCR device Calculate the best reduction dosage to be injected, the first NH at the first SCR device of combinational estimation3Storage level and the second SCR device 2nd NH at place3Storage is horizontal.The control of reducing agent injection further includes a certain amount of to inject to the transmission order of reducing agent syringe Reducing agent.
In one or more examples, the first model uses the first NO of the inlet from the first SCR devicexMeasurement and 2nd NO in the exit from the first SCR devicexMeasurement.In addition, the second model uses the exit from the first SCR device The 2nd NOx3rd NO of measurement and the exit from the second SCR devicexMeasurement.In addition, in one or more examples, the One model uses the first NH in the exit from the first SCR device3The amount of the reducing agent of estimation and injection.In one or more In example, the second model uses the first NH in the exit from the first SCR device3Estimation and going out from the second SCR device The 2nd NH at mouthful3Estimation.In response to the exhaust system including the second SCR device, calculates best reduction dosage and be included in first The exit of SCR device maintains NH3Amount and NOxAmount between the first predetermined outlet weighed and maintain the second SCR device The NH at place3Amount and NOxAmount between the second predetermined tradeoff.
It is a kind of real for controlling the computer that reducing agent is injected into emission control systems according to one or more embodiments Existing method includes first choice catalysis reduction (SCR) device, including determines whether emission control systems include the 2nd SCR dress It sets.In response to only including the exhaust system of the first SCR device, the control of reducing agent injection includes the based on the first SCR device One model calculates the amount of the reducing agent to be injected, and the first model estimates the first NH at the first SCR device3Storage is horizontal.Response In the exhaust system including the second SCR device, the control of reducing agent injection includes the first model based on the first SCR device and the The combination of second model of two SCR devices calculates the best reduction dosage to be injected, and first at the first SCR device of combinational estimation NH3Horizontal the 2nd NH at the second SCR device of storage3Storage is horizontal.The control of reducing agent injection further includes injecting to reducing agent Device sends order to inject a certain amount of reducing agent.
In one or more examples, the first model uses the first NO of the inlet from the first SCR devicexMeasurement and 2nd NO in the exit from the first SCR devicexMeasurement.In addition, the second model uses the exit from the first SCR device The 2nd NOx3rd NO of measurement and the exit from the second SCR devicexMeasurement.In addition, in one or more examples, the One model uses the first NH in the exit from the first SCR device3The amount of the reducing agent of estimation and injection.In one or more In example, the second model uses the first NH in the exit from the first SCR device3Estimation and going out from the second SCR device The 2nd NH at mouthful3Estimation.In response to the exhaust system including the second SCR device, calculates best reduction dosage and be included in first The exit of SCR device maintains NH3Amount and NOxAmount between the first predetermined outlet weighed and maintain the second SCR device The NH at place3Amount and NOxAmount between the second predetermined tradeoff.
By the detailed description below in conjunction with attached drawing, the features described above and advantage of the disclosure and other feature and advantage will It becomes apparent.
Detailed description of the invention
Only by way of example, described in detail below, occur other feature, advantages in the detailed description with reference to attached drawing And details, in which:
Fig. 1 is the general schematic view of engine and associated exhaust after treatment system, and the system configuration is at processing by sending out The exhaust stream that motivation generates；
Fig. 2 depicts the block diagram that control system is injected according to the reducing agent of one or more embodiments；And
Fig. 3 depicts the amount of the reducing agent that exhaust system is injected into for determination according to one or more embodiments The flow chart of illustrative methods.
Specific embodiment
It is described below and is substantially merely exemplary, it is no intended to limit the disclosure, application or purposes.It should be understood that It is that throughout the drawings, corresponding appended drawing reference indicates identical or corresponding component and feature.As used herein, Xiang Mo Block refers to processing circuit, may include specific integrated circuit (ASIC), electronic circuit, processor (shared, dedicated or group) With execute the memory modules of one or more softwares or firmware program, combinational logic circuit and/or provide the function its His suitable components.
In general, with reference to shown in Fig. 1 configure, schematic diagram depict the internal combustion engine 12 according to one or more embodiments, The embodiment of control system 84 and exhaust-gas treatment system 10.In description herein, engine 12 is described as diesel engine, However, engine 12 can be petrol engine in one or more examples.Exemplary diesel engine 12 and control system 84 include four cycle internal combustion diesel engines 12 and electronic engine control module (ECM) 238, be can be configured to according to retouching herein The control method and strategy stated realize the emission control of the exhaust stream 16 at tail pipe 19.Engine may include known compression-ignited hair Motivation, the operating instruction with main lean of stoichiometric with exhaust.Alternatively, diesel engine 12 may include engine, which matches It is set to using any one of various engines configuration and correlation engine control strategy, and further includes being counted with dilution Those of operating instruction of amount, such as homogeneous charge compression ignition engine.
Diesel engine 12 can be any diesel engine configuration or application, including various vehicle applications are (for example, vapour Vehicle, ship etc.) and various non-vehicle applications (for example, pump, generator etc.).During operation, diesel engine 12 generate by The exhaust feeding flow or stream that arrow 16 indicates, it includes the discharge ingredient of control and non-control, generally include component gas and Grain substance.Exhaust-gas treatment system 10 is used for the ingredient of control (for example, various hydrocarbons (HC), carbon monoxide (CO), nitrogen Oxide (NOx) and particulate matter (PM)) it is converted into the ingredient of non-control, for example, nitrogen (N2) and water (H2O)。
Exhaust-gas treatment system 10 includes pipeline, connector and other suitable flow channels and connection features, they are limited together Determine receiving channel, which is configured to receive the exhaust stream 16 from engine 12 and be discharged from tail pipe 19 processed Exhaust stream 16.As shown, exhaust-gas treatment system 10 includes selective catalytic reduction device (SCR) 24 and underfloor ammonia-SCR Device (uSCR) 25.Exhaust-gas treatment system 10 may also include Diesel Oxidation Catalyst device (DOC) 22.In the downstream of DOC 22, two (serial positioning)-SCR 24 and uSCR 25 is connected in series in a SCR device respectively.
SCR 24 and 25 cooperating of uSCR are with NO present in exhaust 16 that engine is dischargedxDischarge is reduced to can The concentration level of receiving.In general, the gaseous effluent being initially included in exhaust 16 is processed with limit transport to atmosphere In control ingredient amount.Urea injector 236 is located at the upstream of SCR 24, by a certain amount of urea liquid (for example, AdBlue, DEF) it is injected into exhaust stream 16.
Diesel engine 12 is fluidly coupled to outlet manifold 15, and outlet manifold 15 collects each vapour from engine 12 The burning and gas-exhausting product of cylinder discharge simultaneously merges them into exhaust stream 16, which is transported to exhaust-gas treatment system 10。
DOC 22 is installed to exhaust manifold, and with entrance, the entrance and exhaust manifold in direct fluid communication are with the row of reception Air-flow 16.Exhaust stream 16 leaves DOC 22 and flows downstream to SCR 24, for first choice catalysis reduction, subsequently flows to USCR 25 carries out second of selective catalytic reduction.
DOC 22 may include the base metal oxide (such as gama-alumina (γ-that high surface area is dispersed in as fine grained Al2O3)) on platinum (Pt), palladium (Pd) and rhodium (Rh) combination or cerium oxide/zirconium oxide (CeO2-ZrO2).In one or more In example, base metal oxide exists in the utilizable flow of the about 70g/L on SCR 24 to about 150g/L in SCR 24 Anywhere.In other examples, Pt/Pd/Rh is supported on base metal oxide, and the utilizable flow range on SCR 24 is About 1 to about 7g/L.
In one or more examples, SCR 24 includes one or more components, using reducing agent 246 and catalyst come NO and NO in conversion exhaust 162。
SCR catalyst ingredient for SCR 24 and uSCR 25 is usually the material of porous and high surface area, can be also It is effectively operated in the presence of former agent 246 (such as ammonia) to convert the NO in exhaust 16xIngredient.For example, catalyst component can contain It is impregnated with one or more base metal ingredients (such as iron (Fe), cobalt (Co), copper (Cu), vanadium (V), sodium (Na), barium (Ba), titanium (Ti), tungsten (W) and combinations thereof) zeolite.In a specific embodiment, catalyst component, which can contain, is impregnated with copper, iron or vanadium One of or a variety of zeolites.In some embodiments, zeolite can be zeolite beta, y-type zeolite, ZM5 zeolite or any Other crystalline zeolite structures, such as chabasie or USY (overstable Y type) zeolite.In a specific embodiment, zeolite includes water chestnut Zeolite.In a specific embodiment, zeolite includes SSZ.Suitable SCR catalyst ingredient can have high heat structure to stablize Property, especially when being used in series with known particulate filter (PF) device or when being integrated in SCR device, pass through height Temperature exhaust soot combustion technology regeneration.
SCR catalyst ingredient for SCR 24 and uSCR 25 optionally further comprises one or more base metals Oxide is as promotor, to be further reduced SO3Formation and extend catalyst life.In some embodiments, Yi Zhonghuo A variety of base metal oxides may include WO3、Al2O3And MoO3.In one embodiment, WO3、Al2O3And MoO3It can be with V2O5Group It closes and uses.
USCR 25 is located at the downstream of the SCR 24 at underfloor position.In one or more examples, SCR 24 and uSCR The distance between 25 in the range of about 3 feet to about 10 feet.The entrance of uSCR 25 and the outlet fluid of SCR 24 connect It passes to and receives exhaust stream 16.Exhaust stream 16 is downstream communicated to tail pipe opening 19 by the outlet of uSCR 25, and tail pipe opening 19 will row Airflow exits are into atmosphere.
USCR 25 may include (1) base-metal ion replace zeolite and/or base-metal ion replace silicoaluminophosphate and (2) fine grained of hydrogen-storing material.Zeolite and silicoaluminophosphate are open-framework, micropore and ammonia absorbability polycrystalline molecular screen material, It preferably uses Cu or Fe ionic compartmentation.In one or more examples, the particle that base-metal ion replaces is present in uSCR in total From anywhere in the utilizable flow of about 120g/L to about 180g/L on 25.Hydrogen-storing material is the gold with storage oxygen and releasability Belong to oxide or mixed-metal oxides.In one or more examples, hydrogen-storing material is present in uSCR catalyst 25 From anywhere in the utilizable flow of about 5g/L to about 50g/L on uSCR 25.Any suitable granular materials point can be used Cloth.The fine grained of zeolite/silicoaluminophosphate and hydrogen-storing material that base-metal ion replaces can be applied for example in single washcoat It is uniformly mixed in layer, or optionally, is reduced to separation and discrete contact wash coat or region.Hydrogen-storing material can also To concentrate on the entrance or near exit of uSCR 25, or with some other non-uniform Distributions concentration.
The zeolite that can be used for preparing the base-metal ion substitution of uSCR 25 includes the zeolite beta of Cu or Fe substitution, the boiling of Y type Stone, ZSM-5 zeolite, chabasie zeolite or USY (superstable gamma-type) type zeolite.In addition, can be used for preparing the base metal of uSCR 25 from The silicoaluminophosphate (SAPO) that son replaces includes SAPO-5, SAPO-34 or SAPO-44 that Cu or Fe replaces.It may be embodied in Some special metal oxides or mixed-metal oxides in uSCR 25 as hydrogen-storing material are containing cerium and containing the metal oxygen of praseodymium Compound or mixed-metal oxides, such as CeO2、Pr6O11、CeO2—ZrO2、CuO—CeO2、FeOX—CeO2(1.0≦X≦ 1.5)、MnOx—CeO2(1.0≤X≤3.5) and Pr6O11—CeO2.Each quilt in these materials without being bound by theory Think the oxygen (higher and lower) for being adapted to non-stoichiometry unit cell amount with lattice structure without decomposing.This property Matter is equal to the ability that oxygen is reversibly stored and discharged in response to the partial pressure of oxygen in exhaust stream 16 and/or with NOxDuring reduction The changes in balance of the partial spent of oxygen.
When diesel engine 12 is run, exhaust-gas treatment system 10 removes the emission of various control from exhaust stream 16, The amount for sliding into the ammonia of exhaust stream 16 is limited simultaneously.Exhaust stream 16 is first by the SCR 24 of close-coupled and then by under floor USCR 25.The combination catalytic activity of SCR 24 and uSCR 25 can continuously processing be arranged under various engine conditions Air-flow 16.Initial NOxReduction process is carried out in SCR 24, wherein leaving the NO of DOC 22xWith the NH being stored in SCR 243Instead It answers.At uSCR 25, any NO escaped by SCR 24xThe NH being stored in uSCR 253Reduction, further reduced NO in processed exhaust stream 16xConcentration level.The NH being stored in SCR 24 and uSCR 253From urea injector 236, Work as NH3When being captured by uSCR 25, the NH that is stored by uSCR 253From SCRF 24.Exhaust-gas treatment system 10 further includes reducing agent Injector system 84, control are injected directly into the amount in SCR 24 with indirect injection to the reducing agent in uSCR 25.
The air/fuel mixing for being supplied to engine 12 is constantly adjusted by electronic fuel injection system (not shown) Object, to realize scheduled air fuel mass ratio, such as air-fuel ratio can be in the range of 15 to 50 or other diesel oil 15 to 80 in engine application.The burning of air/fuel mixture in the cylinder of engine 12 is that exhaust stream 16 provides phase To a large amount of nitrogen (such as > 70vol.%), a small amount of oxygen and by carbon monoxide, HC and NOxThe unwanted gaseous effluent of composition. Existing oxygen amount is generally less than about 2.0vol.%.Existing carbon monoxide, HC and NOxAmount typically respectively about 0.8vol.% Or lower, about 800ppm or lower and about 1500ppm or lower.The NO of exhaust stream 16xConstituency generally includes big molar ratio NO (is greater than 90mol%).It should be noted that above-mentioned value is example, and in one or more embodiments, value can with arrange above Value out is different.It should be appreciated that above-mentioned value is exemplary, and in one or more examples, engine 12 can be upper State measurement it is different from measurement described herein in the case where operate.
However, according to engine calibration and operating condition, the instantaneous air fuel mass ratio of air/fuel mixture can be with It is changed between 15 to 80.These variations cause the chemical component of exhaust stream 16 to change in particular bound.
The NH that SCR 24 is received and injected by urea injector 2363246 mixed exhaust streams 16, and store NH3.In the presence of NO in exhaust 16xThe NH of gas and storage3Reaction.In doing so, SCR 24 will be vented the NO in 16 includedxIt is reduced to N2And H2O.In some operating conditions, SCR 24 may skid off NH3.Work as NOxWhen escaping from the first SCR 24, this is by NH3For To uSCR 25, catalysis NO is supplemented with drivingxReduction reaction.The NH being stored in SCR 24 and uSCR 253From urea injector 236；Work as NH3When skidding off or escape from SCR 24, the NH of the storage of uSCR 253It is exported from SCRF.
USCR 25 receives the exhaust stream 16 from SCR 24.USCR 25 passes through the NH that Coutinuous store is skidded off from SCR 243 Ammonia and the NO for making itself and 24 downstream SCRxIt reacts and facilitates the NO being further reduced in exhaust stream 16x.If urea injector 236 have injected suitable 246 (urea NH of reducing agent3), then two interactions for going back original system SCR 24 and uSCR 25 cause NOxThe significant reduction of discharge.Any number of event can slightly reduce the NO of SCR 24xTransformation efficiency simultaneously allows NOxPass through row Air-flow 16 reaches uSCR 25.Pass through the NO of (slipping over) SCR 24xIt is stored in the ammonia reduction of uSCR25.USCR 25 adapts to row The ability and NO of the variation of the chemical component of air-flow 16xHelp to limit both substance escapings with the out-phase peak concentration in ammonia Into atmosphere.
Include the hydrogen-storing material offer storage oxygen supply in uSCR 25, enhances ammonia and NOxBetween catalysis reduction it is anti- It answers.When there is no NOxWhen, hydrogen-storing material absorbs oxygen from low oxygen content exhaust stream 16.Then the oxygen of accumulation is extracted to supplement exhaust A small amount of available oxygen in stream 16.NO is realized in the inflow of this storage oxygen in several waysxReduction efficiency increases.Firstly, additional oxygen Improve NOxReduction reaction (NO and NO2) overall reaction dynamics because oxygen is rare to can have speed limit effect.Secondly, additional Oxygen promote NO be oxidized to NO2.The oxidation reaction reduces NO in uSCR 25xNO and NO2Molar ratio.This adjusting is ideal , because working as NO/NO2When molar ratio is reduced to preferably from about 1.0 (equimolar) from the initial generation of engine 12, NOxOverall reduction Usually it is more effectively carried out.
Fig. 2 depicts the block diagram that control system 84 is injected according to the reducing agent of one or more embodiments.It should be noted that figure 2 depict the simplification view of exhaust system, and without describing one or more components, such as DOC 22.It should further infuse Meaning, in one or more embodiments, reducing agent injection control system 84 may include it is other in addition to it is discribed those it Outer component, and discribed block diagram is used to describe the technical solution of this paper.SCR 24 and uSCR 25 receives reducing agent 246, Such as with variable dosage rate.Reducing agent 246 can be supplied from reducing agent source of supply 234.In one or more examples, reduction Agent 246 is injected into exhaust pipe 14 at the position of 24 upstream SCR using urea injector 236.Reducing agent 246 can be Gas, liquid or aqueous solution form, such as aqueous solution of urea.In one or more examples, reducing agent 246 can be with syringe Air mixing in 236, to help to inject spraying dispersion.SCR 24 and uSCR 25 reduce exhaust 16 using reducing agent 246 In NOx。
It further includes control module 238 that reducing agent, which injects control system 84, is operably connected to via multiple sensors 1 engine 12 of monitoring figure and SCR device 24 and 25.As it is used herein, item module refers to specific integrated circuit (ASIC), electronic circuit, processor (shared, dedicated or group) and execute one or more softwares or firmware program memory, The component of other proper functions described in combinational logic circuit and/or offer.For example, control module 238 can execute SCR chemistry Model, as described below.Control module 238 can be operatively attached to engine 12, SCR 24, urea injector 236, uSCR 25 and/or one or more sensors.
Sensor may include the first NOxSensor 242, the 2nd NOxSensor 243 and the 3rd NOxSensor 244, Mei Gechuan Sensor and exhaust pipe 14 are in fluid communication.NOxSensor 242,243,244 detects NOxThem be on close level in exhaust pipe Position, and generate NOxSignal corresponds to NOxIt is horizontal.In some embodiments, NOxLevel may include concentration, mass flowrate Or volume flow rate.For example, by NOxThe NO that sensor generatesxSignal can be explained by control module 238.Control module 238 may be used also With with one or more temperature sensor communications, such as Fig. 1 temperature sensor 32.In one or more examples, the first NOxIt passes Sensor 242 can be set at the downstream of engine 12, DOC inlet or at DOC outlet, to measure the NO of 24 upstream SCRxIt is dense Degree, so as to detect SCR 24 inlet NOxIt is horizontal.In a kind of finally situation, due to NOxSensor is to ammonia NH3Intersect quick Sense, therefore NOxSensor 242 is arranged before urea injector 236；2nd NOxThe downstream of SCR 24 is arranged in sensor 243 With the upstream of uSCR 25, to detect the NO of uSCRF25 (or outlet of SCR 24) inletxIt is horizontal；And the 3rd NOxSensor 244 are arranged in the downstream of uSCR 25, to detect the NO in the exit of uSCR 25xIt is horizontal.In one or more examples, first NOxSensor 242 is located at the upstream of DOC 22, the 2nd NOxSensor 243 is located at the exit of SCR 24, the 3rd NOxSensor 244 are located at the exit of uSCR 25.It should be noted that the position for the sensor described in Fig. 2 is illustrative, and at one Or in multiple embodiments, sensor may be at the position different from discribed position.In addition, in one or more embodiments In, the sensor with the sensor different number described herein can be used.
Reducing agent 246, which can be, can decompose in the presence of being vented 16 and/or heat or react to form anyization of ammonia Close object.When urea is injected into thermal exhaust 16, water evaporation and urea is thermally decomposed into NH3And CO2.Then by NH3Molecule storage There are in 25 component of SCR 24 or uSCR to carry out NOxReduction.
Equation (1)-(5), which provide, is related to the NO of ammoniaxThe exemplary chemical reaction of reduction.
6NO+4NH3→5N2+6H2O (1)
4NO+4NH3+O2→4N2+6H2O (2)
6NO2+8NH3→7N2+12H2O (3)
2NO2+4NH3+O2→3N2+6H2O (4)
NO+NO2+2NH3→2N2+3H2O (5)
It should be appreciated that equation (1)-(5) are merely illustrative, it is not meant to for SCR 24 and uSCR 25 to be limited in Specific NOxReduction mechanism is also not excluded for the operation of other mechanism.SCR 24 and uSCR 25 can be configured to execute above-mentioned NOx Reduction reaction, above-mentioned NOxThe combination of reduction reaction and other NOxAny one of reduction reaction.
In various embodiments, reducing agent 246 can be diluted with water.In the embodiment that reducing agent 246 is diluted with water, heat (for example, from exhaust) evaporation water, and ammonia is supplied to SCR 24 and uSCR 25.As needed, non-ammonia reducing agent can be used Make all or part of substitute of ammonia.Following reaction (6), which is provided, generates exemplary the one of ammonia by evaporating to decompose with urea As chemically react.
(NH2)2CO+H2O→2NH3+CO2 (6)
It should be appreciated that equation (6) are merely illustrative, it is not meant to urea or other reducing agents 246 decomposing limit It is formed on specific single mechanism, is also not excluded for the operation of other mechanism.
Modeling is carried out to the operation of two component SCR 24 and uSCR 25 and optimization is that solution described herein is solved Technological challenge certainly.In addition, solution described herein helps to control the operation of both SCR 24 and uSCR 25 and come From the gained NO of exhaust-gas treatment system 10x, only one reducing agent (urea) syringe 236 is located at the upstream of SCR 24.Cause This, technical solution promotes system and modularity control method, is managed in a flexible way using Single Controller module 238 25 framework of SCR 24 and uSCR.Solution described herein is this to promote by using Model Predictive Control (MPC) method Flexibility considers uSCR 25 and optimizes the overall performance of exhaust-gas treatment system 10, while acting only on single unique urea Syringe 236.
MPC is extended beyond SCR 24 by controller module 238, (only single by one urea injection is best determined The presence of urea injector constrains), while optimizing the NO in 25 exit SCR 24 and uSCRxAnd NH3Power between chemical substance Weighing apparatus.
Fig. 3 is depicted according to one or more embodiments for determining the reducing agent being injected into exhaust-gas treatment system 10 The flow chart of the illustrative methods of 246 amount.Method 300 is realized by controller module 238.In one or more examples, control Device module 238 processed executes the one or more computer executable instructions being stored in computer readable storage means to realize this Method.Alternately or in addition, which includes that controller module 238 can according to one or more specific integrated circuits or scene Program gate array configuration operation.
Method 300 is included in 305 and determines that uSCR 25 whether there is and will inject supply reducing agent by reducing agent.It can To be determined based on predetermined flag, whether predetermined flag instruction uSCR 25 is included in exhaust-gas treatment system 10.If no USCR 25 is controlled, then method 300 is included in 310 reading, first group of input signal.First group of input signal includes coming from first NOxSensor 242 and the 2nd NOxThe measuring signal of sensor 243.The temperature that first group of input signal may also include SCR 24 is surveyed Amount and SCR 24 in by F indicate gas mass flow rate.
This method further includes that the NH of SCR 24 is estimated at 3203And NOxOutput.The estimation includes the operation using SCR 24 SCR state observer model.SCR state observer may include prediction and calibration phase based on model.Estimation includes calculating The NH of the estimation of SCR 243Storage is horizontal, and further calculates the NO in the exit of SCR 24xEstimation and NH3Estimation.SCR state The SCR physical model that estimated service life provides as follows:
Here, x (k) is the NH of the estimation at the time interval k at SCR 243Storage is horizontal, TsIt is in control module 238 The sampling of middle iteration post-processing control module or scheduling time, u (k) are the amount of the reducing agent of injection, y1It is the 2nd NOxSensor NO at 243xConcentration, y2It is the NH in 24 exit SCR3Concentration.In addition, estimated service life comes from the first NOxSensor 242 The NO of SCR inletxConcentration (CNOx,in).F (k) indicates that the exhaust flow measurement in k-th of moment SCR 24 (can be and estimate Meter).In addition, the temperature correlated response function a of the multiple pre-calibrations of estimated service life1-a5.In above-mentioned equation, MNOxAnd MNH3Table respectively Show NOxMolal weight and NH3Molal weight.
Referring again to the flow chart of Fig. 3, method 300, which is included in optimize at 330, is injected into exhaust by reducing agent syringe 236 The amount of reducing agent (u (k)) in 16.Controller calculates the amount u (k) for the reducing agent being injected into exhaust, to optimally operate Also original system SCR 24, so that low land maintains the NO in 24 exit SCR as far as possiblexAnd NH3Discharge:
Here, wi expression weight-calibrations, wherein wuIt is the urea amount NH to be injected3inWeight-calibration, wduIt is for true Protect the weight-calibration of the low variation of the injection pattern of reducing agent.In addition, wNOx,SCRFAnd wNH3,SCRFIt is based on 24 exit SCR NOxAnd NH3Between tradeoff weight-calibration.In 340 and 350, the reducing agent 246 to be injected of 238 determination of control module it is best Amount, to minimize the cost function for indicating system performance, such as the NO in 24 exit SCRxAnd NH3Concentration, NOxReduction effect Rate, urea injection effect and the combination of other factors.
Referring again to the flow chart of Fig. 3, if it is determined that control uSCR 25 (that is, uSCR 25 is exhaust-gas treatment system 10 A part；305), method 300 is included in the second input group of reception at 360；Otherwise, SCRF 24 is used only at 340.The Two input groups include coming from the first NOxSensor 242, the 2nd NOxSensor 243 and the 3rd NOxThe NO of sensor 244xSensor Reading, third reading are exported from uSCR.Second input group further includes one or more temperature sensors by each device 25 temperature of 24 temperature of SCR and uSCR of measurement.In addition, the second input group includes by SCR 24 and by the gas of uSCR 25 Weight flow rate.
In addition, this method includes the viewer based on model, with estimate at 370 one of SCR 24 and uSCR 25 or Multiple values.Estimation includes the NH calculated at SCR 24 and uSCR 253Storage is horizontal.In addition, estimation include calculate SCR outlet and The NO in the exit uSCRxAnd NH3.Estimation can be based on the uSCR equation below based on physics:
Here, CNH3,in,uSCRIt (k) is the y from equation (7)2And C (k),NOx,in,uSCRIt (k) is the y from equation (7)1 (k)。y1,uSCR(k) and y2,uSCR(k) NO in the exit uSCR is respectively indicatedxAnd NH3Concentration.
Method 300 further includes optimizing the amount for the reducing agent (u (k)) injected by reducing agent syringe 236 at 380.Optimization Combination including linearisation SCR model and uSCR model from equation (7) and (9).The combination of SCR 24 and uSCR 25 it is linear Changing model can be expressed as follows:
Wherein:
U (k)=CNH3,in(k)
And
Here, Θ is the NH of SCR 243Memory capacity, θ (k) are the NH at the SCR 24 of time k3Storage is horizontal, ΘUF It is the NH of uSCR 253Memory capacity, θuSCR(k) it is NH at the uSCR 25 of time k3Storage is horizontal.
Method 300 includes optimizing the reducing agent (u (k)) being injected into exhaust 16 by reducing agent syringe 236 at 390 Amount.Optimization includes Real-time solution Numerical Optimization with the optimised quantity of the urea to be injected of determination, to minimize expression system The cost function of performance.For example, cost function may include the NO in the outlet SCR and/or the exit uSCRxAnd NH3Concentration, NOxReduction Efficiency, urea injection act on and the combination of other such parameters as described herein.
Here, other than the item from equation (8), w include wNOx,uSCRAnd wNH3,uSCR, they are uSCR respectively The NO in 25 exitsxThe weight-calibration of measurement, and the NH in 25 exit uSCR3Estimation.Therefore, controller module 238 is negative Duty calculates the best reduction dosage to be injected, to maintain the NH in the exit of SCR 243Amount and NOxAmount between it is first pre- Fixed-ratio, and maintain the NH in 25 exit uSCR3Amount and NOxAmount between the second estimated rate.
It can solve to optimize by using linear and nonlinear programming technique, by calculating each equation (12) most Small u (k) determines the amount of the reducing agent 246 to be injected.Therefore, method 300, which is included in 350 determinations, will be injected into gas exhaust treatment system The optimum level of reducing agent 246 in system 10.In one or more examples, the optimum level of reducing agent 246 is to pass through optimization The minimum u (k) that expression formula (or in the case where no uSCR, equation (8)) in equation (12) calculates.
Controller module 238 injects the reducing agent 246 of corresponding amount according to u (k) the value indication injector 236 of calculating.As The reducing agent 246 of order amount is injected into exhaust-gas treatment system 10 by response, syringe 236.
Solution described herein helps to improve the emission control systems being used together with internal combustion engine, such as in vehicle Used in those.For example, technical solution provides a kind of control strategy, the control strategy optimization is by SCR 24 and uSCR 25 The overall performance of the exhaust-gas treatment system of composition, by tail pipe NOxDischarge maintains within a predetermined range, and single go back is used only Former agent (urea) syringe 236, at 340.It is grasped in addition, technical solution facilitates controller module 238 based on calibration value Make, calibration value instruction controller module 238 is the combined reducing agent for only calculating SCR 24 or SCR 24 and uSCR 25 Amount.System automatically processes institute's arrangement, is not necessarily to any manual intervention.
Therefore, the techniques described herein scheme includes two SCR devices, SCR using the optimization of single reducing agent syringe 236 The performance of the entire exhaust-gas treatment system 10 of 24 and uSCR 25.Single reducing agent syringe is controlled so that inject can be in the first SCR The reducing agent of the calculation amount of device (such as SCR 24) direct injection and the second SCR device (such as uSCR 25) indirect injection.Make Reduction dosage is calculated with the model based on physics, and by solving the problems, such as that the programming of the numerical value in ECM processor calculates also in real time The amount of former agent.Therefore, solution described herein provides system and modularity control method, in a flexible way management tool There is SCR the and/or SCR+uSCR framework of single optimizing controller and injector system.
Although describing above disclosure by reference to exemplary embodiment, it will be appreciated, however, by one skilled in the art that not In the case where being detached from its range, various changes can be carried out and its element can be replaced with equivalent.In addition, not departing from this In the case where disclosed essential scope, many modifications can be carried out so that specific condition or material adapt to the introduction of the disclosure.Cause This, it is intended that the present disclosure is not limited to disclosed specific embodiments, but will include all embodiments fallen within the scope of its.

Claims (10)

1. a kind of for handling the emission control systems of motor vehicles I. C. engine exhaust, the emission control systems include:
Reducing agent syringe；
First choice catalysis reduction (SCR) device；
Second SCR device；And
System design based on model device, is configured to control the reducing agent and is injected into the exhaust, the reducing agent injection The control includes:
Determine the NO in the exit of first SCR devicexAmount and NH3Amount；
Determine the NO in the exit of second SCR devicexAmount and NH3Amount；
The amount of the reducing agent to be injected is calculated to maintain the NH in the exit of first SCR device3The amount and NOx The amount between the first estimated rate, and maintain the NH in the exit of second SCR device3The amount with NOxThe amount between the second estimated rate, to ensure selective catalytic reduction system operating, first SCR device and described The optimum operation of second SCR device；And
Send the reducing agent that the calculation amount is injected by the received order of the reducing agent syringe.
2. emission control systems according to claim 1, wherein determining the NH in the exit of first SCR device3 NH of the amount based on the first estimation for calculating first SCR device3Storage is horizontal, and also based on described first The inlet of SCR device receives NOxMeasurement.
3. emission control systems according to claim 2, wherein determining the NH in the exit of second SCR device3 NH of the amount based on the second estimation for calculating second SCR device3Store horizontal and described first SCR device The NH in the exit3The amount.
4. emission control systems according to claim 3, wherein determining the NH in the exit of second SCR device3 The amount also based on the exit of first SCR device receive NOxMeasurement.
5. emission control systems according to claim 1, wherein first SCR device is SCR filter.
6. emission control systems according to claim 5, wherein second SCR device is SCR device under floor.
7. emission control systems according to claim 1, wherein the amount for calculating reducing agent includes based on including described The combined state observer of the physical model of first SCR device and second SCR device estimates second SCR device The exit NH3The amount and NOxThe amount.
8. a kind of for handling the selective catalysis for being configured to execute exhaust by the exhaust system of the exhaust of engine exhaust also Former (SCR), the exhaust system include:
At least the first SCR device；
Controller, is configured to injection of the control reducing agent into the exhaust, and the control of the reducing agent injection includes:
Determine whether the exhaust system includes the second SCR device；
In response to only including the exhaust system of first SCR device, based on the first model of first SCR device The amount of the reducing agent to be injected is calculated, first model estimates the first NH at first SCR device3Storage is horizontal；
In response to the exhaust system including second SCR device, first model based on first SCR device Combination with the second model of second SCR device calculates the best reduction dosage to be injected, the combinational estimation institute State the first NH at the first SCR device3Horizontal the 2nd NH at second SCR device of storage3Storage is horizontal；And
Order is sent to reducing agent syringe to inject a certain amount of reducing agent.
9. exhaust system according to claim 8, wherein first model uses entering from first SCR device The first NO at mouthfulx2nd NO of measurement and the exit from first SCR devicexMeasurement.
10. exhaust system according to claim 9, wherein second model is used from first SCR device 2nd NO in the exitx3rd NO of measurement and the exit from second SCR devicexMeasurement.
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