CN103998735A - 柴油发动机的废气净化方法和废气净化系统 - Google Patents

柴油发动机的废气净化方法和废气净化系统 Download PDF

Info

Publication number
CN103998735A
CN103998735A CN201280061018.1A CN201280061018A CN103998735A CN 103998735 A CN103998735 A CN 103998735A CN 201280061018 A CN201280061018 A CN 201280061018A CN 103998735 A CN103998735 A CN 103998735A
Authority
CN
China
Prior art keywords
exhaust
diesel engine
exhaust gas
waste gas
nox absorbing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN201280061018.1A
Other languages
English (en)
Other versions
CN103998735B (zh
Inventor
长冈大治
中田辉男
游座裕之
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Isuzu Motors Ltd
Original Assignee
Isuzu Motors Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Isuzu Motors Ltd filed Critical Isuzu Motors Ltd
Publication of CN103998735A publication Critical patent/CN103998735A/zh
Application granted granted Critical
Publication of CN103998735B publication Critical patent/CN103998735B/zh
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • 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
    • F01N9/00—Electrical control of exhaust gas treating apparatus
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9495—Controlling the catalytic process
    • 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
    • F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
    • F01N3/0828—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents characterised by the absorbed or adsorbed substances
    • F01N3/0842—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
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D21/00—Controlling engines characterised by their being supplied with non-airborne oxygen or other non-fuel gas
    • F02D21/06—Controlling engines characterised by their being supplied with non-airborne oxygen or other non-fuel gas peculiar to engines having other non-fuel gas added to combustion air
    • F02D21/08—Controlling engines characterised by their being supplied with non-airborne oxygen or other non-fuel gas peculiar to engines having other non-fuel gas added to combustion air the other gas being the exhaust gas of engine
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/0002—Controlling intake air
    • F02D41/0005—Controlling intake air during deceleration
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D41/0047—Controlling exhaust gas recirculation [EGR]
    • F02D41/005—Controlling exhaust gas recirculation [EGR] according to engine operating conditions
    • F02D41/0052—Feedback control of engine parameters, e.g. for control of air/fuel ratio or intake air amount
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D41/0047—Controlling exhaust gas recirculation [EGR]
    • F02D41/005—Controlling exhaust gas recirculation [EGR] according to engine operating conditions
    • F02D41/0055—Special engine operating conditions, e.g. for regeneration of exhaust gas treatment apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/021—Introducing corrections for particular conditions exterior to the engine
    • F02D41/0235—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
    • F02D41/027—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus
    • F02D41/0275—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus the exhaust gas treating apparatus being a NOx trap or adsorbent
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/20—Reductants
    • B01D2251/208—Hydrocarbons
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/90—Physical characteristics of catalysts
    • B01D2255/91—NOx-storage component incorporated in the catalyst
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2258/00—Sources of waste gases
    • B01D2258/01—Engine exhaust gases
    • B01D2258/012—Diesel engines and lean burn gasoline engines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9404—Removing only nitrogen compounds
    • B01D53/9409—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
    • F01N2240/00—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
    • F01N2240/36—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being an exhaust flap
    • 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
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/0002—Controlling intake air
    • F02D2041/0017—Controlling intake air by simultaneous control of throttle and exhaust gas recirculation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/0002—Controlling intake air
    • F02D2041/0022—Controlling intake air for diesel engines by throttle control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/08—Exhaust gas treatment apparatus parameters
    • F02D2200/0802—Temperature of the exhaust gas treatment apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/50—Input parameters for engine control said parameters being related to the vehicle or its components
    • F02D2200/501—Vehicle speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/18—Circuit arrangements for generating control signals by measuring intake air flow
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D9/00—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits
    • F02D9/04—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits concerning exhaust conduits
    • 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
    • Y02T10/40—Engine management systems

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Biomedical Technology (AREA)
  • Environmental & Geological Engineering (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Toxicology (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Exhaust Gas Treatment By Means Of Catalyst (AREA)
  • Control Of Throttle Valves Provided In The Intake System Or In The Exhaust System (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)

Abstract

一种抑制驾驶性能和油耗的恶化、并且将废气净化的柴油发动机的废气净化方法，当废气(G)成为富还原状态时，在NOx吸附还原催化剂(11)的温度为规定温度以上、并且处于从搭载了柴油发动机(1)的车辆的规定速度以上的车速起的减速时，开放EGR阀(15)，并且关闭吸气节流阀(6)，接着，关闭设于NOx吸附还原催化剂(11)的下游的排气节流阀(20)，作为还原剂将燃料供给至NOx吸附还原催化剂(11)。

Description

柴油发动机的废气净化方法和废气净化系统
技术领域
本发明涉及废气净化方法和废气净化系统，更详细地说，涉及能够抑制驾驶性能和油耗的恶化、并且将废气净化的柴油发动机的废气净化方法和废气净化系统。
背景技术
在柴油发动机的废气净化系统中，为了降低废气中含有的氮氧化物(NOx：Nitrogen Oxide)，例如像日本专利特开2009-275561号公报所记载的那样，与汽油发动机不同而使用NOx吸附还原催化剂。这是因为，柴油发动机的废气的空燃比处于贫(lean)氛围，因而不能够直接使用在汽油发动机那样的理论空燃比氛围中使用的三元催化剂。
该柴油发动机的废气净化系统进行以下的再生操作：在贫状态时使废气中的NOx暂时吸附于NOx吸附材料(K或Ba等碱金属或碱土金属)，并定期地使其成为富(rich)状态，从而使吸附的NOx释出而通过三元功能来还原。
为了使柴油发动机的废气成为富状态，需要调节吸气量，或者通过后喷射或排气喷射将燃料供给至废气。然而存在以下问题：前者的吸气量减少导致车辆的驾驶性能恶化，后者的燃料供给导致油耗的恶化。
在先技术文献
专利文献：
专利文献1：日本专利的特开2009-275561号公报
发明内容
发明要解决的问题
本发明的目的在于，提供能够抑制驾驶性能和油耗的恶化、并且将废气净化的柴油发动机的废气净化方法和废气净化系统。
用于解决课题的技术手段
达成上述目的的本发明的柴油发动机的废气净化方法，使用NOx吸附还原催化剂将搭载于车辆的柴油发动机的废气净化，当所述废气成为富还原等待状态时，在所述NOx吸附还原催化剂的温度为规定温度以上、且处于从所述车辆的规定速度以上的车速起的减速时，开放EGR阀，并且关闭吸气节流阀，接着，关闭设于所述NOx吸附还原催化剂的下游的排气节流阀，将还原剂供给至所述NOx吸附还原催化剂。
在上述的柴油发动机的废气净化方法中，从EGR阀的开放和吸气节流阀的关闭起，在规定时间经过后，关闭排气节流阀。或者，从EGR阀的开放和吸气节流阀的关闭起，在柴油发动机的吸气的空气流量值成为基准值以下时，关闭排气节流阀。
另外，优选规定温度为200℃，并且规定速度为20km/h。
达成上述目的的本发明的柴油发动机的废气净化系统具有：吸气节流阀，安装在搭载于车辆的柴油发动机的吸气通路；NOx吸附还原催化剂，设置于排气通路；EGR阀，安装于从所述吸气通路向所述排气通路连通的EGR通路；以及还原剂供给机构，向所述NOx吸附还原催化剂供给还原剂，该废气净化系统的特征在于，在所述NOx吸附还原催化剂的下游侧的排气通路设置排气节流阀，并且设置控制所述吸气节流阀、EGR阀和排气节流阀的控制机构，当所述排气通路中流动的废气成为富还原等待状态时，在所述NOx吸附还原催化剂的温度为规定温度以上、且处于从所述车辆的规定速度以上的车速起的减速时，该控制机构开放所述EGR阀，并且关闭所述吸气节流阀，接着，关闭所述排气节流阀，启动所述还原剂供给机构。
发明的效果
依照本发明的柴油发动机的废气净化方法和废气净化系统，由于在从规定速度以上的车速起的减速时使废气成为富状态，因而能够抑制驾驶性能的恶化。另外，由于在使废气为富状态时调节废气量，为了使废气成为富状态，供给的燃料较少即可，所以能够抑制油耗的恶化。
附图说明
图1是由本发明的实施方式构成的柴油发动机的废气净化系统的构成图。
图2是说明由本发明的实施方式构成的柴油发动机的废气净化方法的流程图。
图3是表示本发明的柴油发动机的废气净化方法的实施例的曲线图。
具体实施方式
以下，参照附图说明本发明的实施方式。
图1表示由本发明的实施方式构成的柴油发动机的废气净化系统。在装备有该柴油发动机的废气净化系统的柴油发动机1中，从吸入口2吸入至吸气通路3的空气A依次通过空气净化器4和空气流量传感器(MAF传感器)5，在由吸气节流阀6调整吸气量之后，从吸气歧管7向各气筒供给。而且，在通过共轨喷射系统8喷射的燃料燃烧后，成为废气G而从排气歧管9向排气通路10排出，通过NOx吸附还原催化剂11，成为净化后的废气Gc并从排气口12排出。另外，废气G的一部分作为EGR气体Ge向EGR通路13分流，由EGR冷却器14冷却，然后经由EGR阀15向吸气歧管7再次循环。
NOx吸附还原催化剂11构成为：在由γ氧化铝等形成的整体式蜂窝的胞室的担载体的表面，担载催化剂金属和NOx吸附材料。作为催化剂金属，使用Pt或Pd。另外，作为NOx吸附材料，使用K、Na、Li、Cs等碱金属、或Ba、Ca等碱土金属中的任何一种或组合的多种。
在该NOx吸附还原催化剂11中，在废气G为贫状态时，废气G中的NO被氧化催化剂氧化而成为NO2，以NO3-的形态在催化剂内扩散而由NOx吸附材料以硝酸盐的形态吸收。此外，如果废气G为富状态，则NO3-以NO2的形态从NOx吸附材料释出。该释出的NO2通过废气G中含有的未燃HC等还原剂接受氧化催化剂的作用而还原为N2。
为了使废气G成为富状态，通过还原剂供给机构将轻油燃料等还原剂供给至废气G中。作为该还原剂供给机构，例示了向气筒喷射燃料的后喷射、设于排气通路10的燃料喷射喷嘴(未图示)等。此外，使用后者的燃料喷射喷嘴时存在以下优点：能够避免在后喷射的情况下成为问题的发动机油的燃料贫释。燃料供给量的调整通过调整这些还原剂供给机构的喷射量和喷射时期来进行。
在NOx吸附还原催化剂11的入口(上游侧附近)设有催化剂入口排气浓度传感器16和催化剂入口温度传感器17，在出口(下游侧附近)设有催化剂出口排气浓度传感器18和催化剂出口温度传感器19。该排气浓度传感器16、18测定废气G、Gc的空气过剩率λ和NOx浓度。
本发明的柴油发动机的废气净化系统如下构成：在NOx吸附还原催化剂11的下游侧的排气通路10设置排气节流阀20，并且使ECU(EngineControl Unit，发动机控制单元)21具备控制该排气节流阀20、吸气节流阀6及EGR阀15的控制机构的功能。此外，ECU21还进行MAF传感器5、共轨喷射系统8、排气浓度传感器16、18及催化剂温度传感器17、19的控制、以及测定数据的收集。此外，图1中所示的单点划线表示信号的传递路径。
以下，基于图2所示的流程图，说明具有这样的构成的柴油发动机的废气净化系统的废气净化方法。
首先，ECU21判定NOx吸附还原催化剂11是否处于富还原等待状态(S10)。富还原等待状态相当于NOx吸附材料的吸收能力接近饱和的状态。作为判定方法，例示将从排气浓度传感器16、18的测定值算出的NOx吸附量(从上次还原处理起的增量)和NOx净化率与预先设定的阈值进行比较的方法等。
在判定为成为富还原等待状态的情况下，确认NOx吸附还原催化剂11的温度是否为规定温度以上、且搭载了柴油发动机1的车辆是否处于从规定速度以上的车速起的减速时(S20)。NOx吸附还原催化剂11的温度例如能够通过从催化剂温度传感器17、19的测定值算出、或在催化剂附近设置热电偶(未图示)并测定等来求得。另外，规定温度优选为为200℃。NOx吸附还原催化剂11的温度不足200℃时，还原剂的还原作用显著降低。
车辆的车速能够从发动机转速等算出。另外，规定速度优选为20km/h。如果车辆的车速不足20km/h，则从减速到停止为止的时间变短，对于后述的排气节流阀20的关闭以后的还原反应无法取得充分的时间。另外，从共轨喷射系统8的燃料喷射量(例如喷射量＝0)或加速器开度(例如开度＝0°)等来判断车辆处于减速状态。
而且，在NOx吸附还原催化剂11的温度为规定温度以上、且车辆处于从规定速度以上的车速起的减速时的情况下，开放EGR阀15，并且关闭吸气节流阀6(S30)。
接着，当满足关闭排气节流阀20的规定条件时(S40)，关闭排气节流阀20(S50)，启动还原剂供给机构，将燃料供给至废气G中而成为富状态(S60)。该还原剂的喷射量被决定为：从排气浓度传感器16、18算出的空气过剩率λ成为从吸气量算出的目标值。即，空气过剩率λ的目标值如下设定：预先通过实验确定目标值，在控制时参照从该目标值制作的“对于发动机转速和燃料流量的目标值”的三维映射图。然后，根据共轨喷射系统8的筒内喷射量(指示值，或者从排气浓度传感器16、18的测定值和MAF传感器5的测定值算出的值)与从空气过剩率λ的目标值及MAF传感器5的测定值算出的必要燃料流量之差，求得喷射量。
最后，在从燃料的供给起经过一定时间后，或者在车辆的减速结束后，停止还原剂供给机构，并且开放排气节流阀20。
这样，在从车辆的规定速度以上起的减速时使废气G成为富状态，因而能够抑制驾驶性能的恶化。另外，在使废气G成为富状态时，开放EGR阀15且关闭吸气节流阀6和排气节流阀20而调节废气量，因而从还原剂供给机构供给的燃料较少即可，所以能够抑制油耗的恶化。
再者，由于废气G的温度变高且流量变低，因而还原所需的时间变长，所以能够提高还原效率。为了充分地确保该还原所需的时间，需要如上述那样车辆处于从规定速度以上的车速起的减速时。另外，在硬件层面，将排气节流阀设于现有的发动机构成即可，因而能够以低成本实现废气净化系统。
作为关闭排气节流阀20的规定条件(S40)，除了事先确定的规定时间(例如0.1～3秒等)经过后之外，也可以是MAF传感器5的测定值超过基准值的时刻。该MAF传感器5的基准值设定成：关闭排气节流阀20时的排气压力的峰值成为NOx吸附还原催化剂11本身或其附近的传感器16～19等不损坏的程度的值。基准值随着柴油发动机1的尺寸或型号等变化，因而不能一律地设定，但在一般的大型车辆中为大约30～80kPa。
此外，在从EGR阀15的开放和吸气节流阀6的关闭到排气节流阀20的关闭为止设置时间差的情况下，抑制了排气压力的急剧上升，因而即使在高发动机转速下也能够使用排气节流阀20，所以能够容易地实施柴油发动机的废气净化方法。
在图2中，首先判定富还原等待状态，但是也可省略该判定相关的步骤S10。在此情况下，不管富还原等待状态如何，只要NOx吸附还原催化剂11的温度为规定温度以上、且车辆处于从规定速度以上的车速起的减速时，就进行步骤S20～S60的处理，因而能够防止NOx吸附还原催化剂11的温度降低，进一步提高还原效率。
在实际的运转时，有时候在车辆的减速时立即开始加速，但是在这样的情况下，不能够充分地确保还原所需的时间，因而优选地使加速性优先而进行开放排气节流阀20的控制。
[实施例]
在图3中示出了使用图1所示构成的柴油发动机的废气净化系统(实施例)、以及从图1的构成除去排气节流阀20的废气净化系统(比较例)，进行柴油发动机1的废气净化的结果。此外，将NOx吸附还原催化剂11为规定温度以上作为前提。这些废气净化系统中的经时变化如下。
(1)如果判定为处于富还原等待状态，则在从车辆的车速50km/h(相当于发动机转速＝约1500rpm)起的减速时，完全开放EGR阀15，并且完全关闭吸气节流阀6。(2)其结果，废气G的量降低。(3)然后，在实施例中，当废气G的量满足将排气节流阀20关闭的规定条件、即“动作时的排气压力为阈值以下”时，完全关闭排气节流阀20。(4)通过还原剂供给机构供给燃料，将NOx还原。
从图3的结果可知，实施例与比较例相比，减速时的废气G的量与比较例相比变少，废气G的温度的降低变小。
符号说明：
1   柴油发动机
2   吸入口
3   吸气通路
4   空气净化器
5   MAF传感器
6   吸气节流阀
7   吸气歧管
8   共轨喷射系统
9   排气歧管
10  排气通路
11  NOx吸附还原催化剂
12  排气口
13  EGR通路
14  EGR冷却器
15  EGR阀
16  催化剂入口排气浓度传感器
17  催化剂入口温度传感器
18  催化剂出口排气浓度传感器
19  催化剂出口温度传感器
20  排气节流阀
21  ECU

Claims (5)

1.一种废气净化方法，使用NOx吸附还原催化剂将搭载于车辆的柴油发动机的废气净化，该废气净化方法的特征在于，
当所述废气成为富还原等待状态时，
在所述NOx吸附还原催化剂的温度为规定温度以上、且处于从所述车辆的规定速度以上的车速起的减速时，开放EGR阀，并且关闭吸气节流阀，
接着，关闭设于所述NOx吸附还原催化剂的下游的排气节流阀，将还原剂供给至所述NOx吸附还原催化剂。
2.根据权利要求1所述的废气净化方法，其特征在于，
从所述EGR阀的开放和吸气节流阀的关闭起，在规定时间经过后，关闭所述排气节流阀。
3.根据权利要求1所述的废气净化方法，其特征在于，
从所述EGR阀的开放和吸气节流阀的关闭起，在所述柴油发动机的吸气的空气流量值成为基准值以下时，关闭所述排气节流阀。
4.根据权利要求1～3中任一项所述的废气净化方法，其特征在于，
所述规定温度为200℃，且所述规定速度为20km/h。
5.一种废气净化系统，具有：吸气节流阀，安装在搭载于车辆的柴油发动机的吸气通路；NOx吸附还原催化剂，设置于排气通路；EGR阀，安装于从所述吸气通路向所述排气通路连通的EGR通路；以及还原剂供给机构，向所述NOx吸附还原催化剂供给还原剂，该废气净化系统的特征在于，
在所述NOx吸附还原催化剂的下游侧的排气通路设置排气节流阀，并且设置控制所述吸气节流阀、EGR阀和排气节流阀的控制机构，
当所述排气通路中流动的废气成为富还原等待状态时，在所述NOx吸附还原催化剂的温度为规定温度以上、且处于从所述车辆的规定速度以上的车速起的减速时，该控制机构开放所述EGR阀，并且关闭所述吸气节流阀，
接着，关闭所述排气节流阀，启动所述还原剂供给机构。
CN201280061018.1A 2011-12-12 2012-11-13 柴油发动机的废气净化方法和废气净化系统 Active CN103998735B (zh)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2011-271292 2011-12-12
JP2011271292A JP5811822B2 (ja) 2011-12-12 2011-12-12 ディーゼルエンジンの排気ガス浄化方法及び排気ガス浄化システム
PCT/JP2012/079342 WO2013088887A1 (ja) 2011-12-12 2012-11-13 ディーゼルエンジンの排気ガス浄化方法及び排気ガス浄化システム

Publications (2)

Publication Number Publication Date
CN103998735A true CN103998735A (zh) 2014-08-20
CN103998735B CN103998735B (zh) 2016-11-30

Family

ID=

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104819034A (zh) * 2015-04-22 2015-08-05 江苏大学 一种柴油机egr系统可重复利用脱硫颗粒过滤装置
CN106762238A (zh) * 2016-12-08 2017-05-31 浙江吉利罗佑发动机有限公司 一种基于增压式发动机的低压废气再循环系统
CN110520222A (zh) * 2017-03-29 2019-11-29 康明斯排放处理公司 使用可变喷射角喷嘴用于NOx还原剂配给的组件和方法
CN114832623A (zh) * 2022-04-22 2022-08-02 山东交通学院 一种汽油车排放检验机构尾气净化方法及装置

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1298291A2 (en) * 2001-10-01 2003-04-02 Toyota Jidosha Kabushiki Kaisha Exhaust gas purifying apparatus for internal combustion engine and control method thereof
WO2003033892A1 (en) * 2001-10-15 2003-04-24 Toyota Jidosha Kabushiki Kaisha Exhaust gas purifying device and method for internal combustion engine
US20100126142A1 (en) * 2007-06-06 2010-05-27 Toyota Jidosha Kabushiki Kaisha Internal combustion engine exhaust gas control system and control method of internal combustion engine exhaust gas control system
DE102010041673A1 (de) * 2009-09-29 2011-03-31 Ford Global Technologies, LLC, Dearborn Steuerung des Auslassbetriebs eines Motors mit einem Teilchenfilter

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1298291A2 (en) * 2001-10-01 2003-04-02 Toyota Jidosha Kabushiki Kaisha Exhaust gas purifying apparatus for internal combustion engine and control method thereof
WO2003033892A1 (en) * 2001-10-15 2003-04-24 Toyota Jidosha Kabushiki Kaisha Exhaust gas purifying device and method for internal combustion engine
US20100126142A1 (en) * 2007-06-06 2010-05-27 Toyota Jidosha Kabushiki Kaisha Internal combustion engine exhaust gas control system and control method of internal combustion engine exhaust gas control system
DE102010041673A1 (de) * 2009-09-29 2011-03-31 Ford Global Technologies, LLC, Dearborn Steuerung des Auslassbetriebs eines Motors mit einem Teilchenfilter

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104819034A (zh) * 2015-04-22 2015-08-05 江苏大学 一种柴油机egr系统可重复利用脱硫颗粒过滤装置
CN106762238A (zh) * 2016-12-08 2017-05-31 浙江吉利罗佑发动机有限公司 一种基于增压式发动机的低压废气再循环系统
CN110520222A (zh) * 2017-03-29 2019-11-29 康明斯排放处理公司 使用可变喷射角喷嘴用于NOx还原剂配给的组件和方法
CN114832623A (zh) * 2022-04-22 2022-08-02 山东交通学院 一种汽油车排放检验机构尾气净化方法及装置

Also Published As

Publication number Publication date
US9222394B2 (en) 2015-12-29
WO2013088887A1 (ja) 2013-06-20
JP5811822B2 (ja) 2015-11-11
US20140325962A1 (en) 2014-11-06
EP2792865A1 (en) 2014-10-22
JP2013122210A (ja) 2013-06-20
EP2792865A4 (en) 2015-12-02

Similar Documents

Publication Publication Date Title
CN102251834B (zh) 发动机的排气系统中的微粒过滤器的再生
EP3051089B1 (en) Exhaust purifying apparatus for internal combustion engine
US20080245056A1 (en) System operable to control exhaust gas emission of engine
JP2014520228A5 (zh)
CN103958843A (zh) 用于操作排气净化系统的方法
CN101874151B (zh) 排气净化装置和排气净化方法
US9334821B2 (en) Fuel injection control apparatus for engine
JP5811822B2 (ja) ディーゼルエンジンの排気ガス浄化方法及び排気ガス浄化システム
CN103717851A (zh) 内燃机的排气净化装置
JPWO2011108075A1 (ja) 内燃機関の制御装置
US8020373B2 (en) Engine system and method for purge gas regeneration of an exhaust gas treatment device in such a system
KR101272944B1 (ko) 가솔린 엔진의 수트 재생 시스템 및 방법
KR102072193B1 (ko) 촉매 미립자 필터를 포함하는 배기 가스 처리 시스템 및 배기 가스 처리 방법
JP2008157243A (ja) エンジンシステムおよび同システムにおける排ガス処理装置の再生方法
EP2677150A2 (en) Exhaust gas control apparatus of internal combustion engine
JP2016109026A (ja) 内燃機関の排気浄化装置
US20170335733A1 (en) Exhaust gas purification apparatus for internal combustion engine
JP2008095557A (ja) ターボ過給機付きエンジンのサージ防止制御装置及びサージ防止制御方法
CN103998735B (zh) 柴油发动机的废气净化方法和废气净化系统
CN113574257A (zh) 用于使在用汽油运行的机动车的废气系中的经涂层的颗粒过滤器再生的方法和装置
JP5845869B2 (ja) ディーゼルエンジンの排気ガス浄化方法及び排気ガス浄化システム
CN111819349A (zh) 废气净化装置、车辆以及废气净化控制装置
JP2014095303A (ja) エンジンの制御装置
JP2019116876A (ja) センサ診断システム
GB2570908A (en) A method of operating a vehicle

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
C14 Grant of patent or utility model
GR01 Patent grant