双级尿素-选择性催化还原系统对柴油机排放特性的影响研究
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摘要
为满足国Ⅵ排放标准,提出并开发了双级尿素(urea)-选择性催化还原(selective catalytic reduction system,SCR)系统及控制策略,并针对该系统在柴油机上的NOx排放特性及对柴油颗粒捕集器(DPF)被动再生的影响进行了台架验证。结果表明:冷态国际统一瞬态循环(WHTC)双级urea-SCR系统NOx转化效率达到89.2%,比单级urea-SCR系统提高了5.4%,冷起动NOx排放显著降低;热态WHTC双级urea-SCR系统NOx转化效率达到99.3%,比单级urea-SCR系统提高了3.0%;对双级urea-SCR系统尿素喷射量采用闭环控制策略,热态WHTC下DPF平衡点碳载量仅比单级urea-SCR系统提高了0.2g/L,DPF被动再生效果几乎未受影响。
A two-stage urea-selective catalytic reduction(SCR)system and a related control strategy were developed as an alternative solution to fulfilling the ChinaⅥ emissions regulation.Experiments were proceeded to validate the developed system performance in converting NOxand to investigate the influence of the new system on diesel particulate filter(DPF)passive regeneration.The results show that during the world harmonized transient cycle(WHTC)the efficiency of converting NOxby the new system reaches up to89.2%at cold start and up to 99.3% at hot start,5.4% and 3.0% respectively higher than those of the conventional system.The total WHTC emissions are lower than those of the ChinaⅥemissions regulation,which indicates the new system has the potential to satisfy the further emissions legislation.When a closedloop control is adopted for the urea injection,the two-stage urea-SCR system has only 0.2 g/L higher soot loading than the conversional system at DPF balance point under WHTC cycle,exerting very limit influence on the DPF passive regeneration performance.
A two-stage urea-selective catalytic reduction(SCR)system and a related control strategy were developed as an alternative solution to fulfilling the ChinaⅥ emissions regulation.Experiments were proceeded to validate the developed system performance in converting NOxand to investigate the influence of the new system on diesel particulate filter(DPF)passive regeneration.The results show that during the world harmonized transient cycle(WHTC)the efficiency of converting NOxby the new system reaches up to89.2%at cold start and up to 99.3% at hot start,5.4% and 3.0% respectively higher than those of the conventional system.The total WHTC emissions are lower than those of the ChinaⅥemissions regulation,which indicates the new system has the potential to satisfy the further emissions legislation.When a closedloop control is adopted for the urea injection,the two-stage urea-SCR system has only 0.2 g/L higher soot loading than the conversional system at DPF balance point under WHTC cycle,exerting very limit influence on the DPF passive regeneration performance.
引文
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[15]臧志成,朱磊,陈凌云.DPF喷油助燃主被动再生系统电控单元开发[J].内燃机工程,2016,37(5):74-79.ZANG Z C,ZHU L,CHEN L Y.The electronic control unit development of fuel injection combustion active and passive DPF regeneration system[J].Chinese Internal Combustion Engine Engineering,2016,37(5):74-79.
[16]KOTRBA A,GARDNER T P,BAI L,et al.Passive regeneration response characteristics of a DPF system[C/OL].SAE Paper,2013,2013-01-0520.(2013-04-08).https://doi.org/10.4271/2013-01-0520.
[17]李弘扬,蔡忆昔,施蕴曦,等.负荷对柴油机微粒捕集器再生的影响[J].内燃机工程,2016,37(6):200-204.LI H Y,CAI Y X,SHI Y X,et al.The effect of engine load on diesel particulate filter regeneration[J].Chinese Internal Combustion Engine Engineering,2016,37(6):200-204.
[2]SINGH N,RUTLAND V J,FOSTER D E,et al.Investigation into different DPF regeneration strategies based on fuel economy using integrated system simulation[C/OL].SAEPaper,2009,2009-01-1275.(2009-04-20).https://doi.org/10.4271/2009-01-1275.
[3]JOHNSON T V,JOSHI A.Review of vehicle engine efficiency and emission[C/OL].SAE Paper,2017,2017-01-0907.(2017-03-28).https://doi.org/10.4271/2017-01-0907.
[4]SHARP C,WEBB C C,HENRY C.Achieving ultra low NOx emissions levels with a 2017 heavy-duty on-highway TC diesel engine-comparison of advanced technology approaches[C/OL].SAE Paper,2017,2017-01-0956.(2017-03-28).https://doi.org/10.4271/2017-01-0956.
[5]CHILUMUKURU K,GUPTA A,RUTH M,et al.Aftertreatment architecture and control methodologies for future light duty diesel emission regulations[C/OL].SAEPaper,2017,2017-01-0911.(2018-03-28).https://doi.org/10.4271/2017-01-0911.
[6]BüLTE H,SCHRAML S.Technology concept for DEUTZ V-type engines TCD 12.0and TCD 16.0for EU stage IV/US Tier4emission legislation[C]//Shanghai:22nd Aachen Colloquium Automobile and Engine Technology,2013:1193-1205.
[7]SHARP C,WEBB C C,HENRY C,et al.Achieving ultra low NOxemission levels with a 2017heavy-duty on-highway TCdiesel engine and an advanced technology emissions system-NOx management strategies[C/OL].SAE Paper,2017,2017-01-0958.(2017-03-28).https://doi.org/10.4271/2017-01-0958.
[8]HENDRICKSON C S,UPADHYAY D,NIEUWSTADT MV.Selective catalytic reduction control with multiple injector[C/OL].SAE Paper,2017,2017-01-0943.(2017-03-28).https://doi.org/10.4271/2017-01-0943.
[9]JOHNSON T V.Diesel emission control in review[C/OL].SAE Paper,2009,2009-01-0121.(2009-04-20).https://doi.org/10.4271/2009-01-0120.
[10]J??SKEL?INEN H,MAJEWSKI W A.Heavy-duty diesel engines with aftertreatment[EB/OL].(2018-01-04).https://www.dieselnet.com/tech/engine_heavy-duty_aftertreatment.php.DieselNet.
[11]DAHODWALA M,JOSHI S,KOEHLER E W,et al.Strategies for meeting phase 2GHG and ultra-low NOx emission standards for heavy-duty diesel engines[C/OL].SAE Paper,2018,2018-01-1429.(2018-04-03).https://doi.org/10.4271/2018-01-1429.
[12]SCH?R C M,ONDER C H,GEERING H P,et al.Control of an SCR catalytic converter system for a mobile heavy-duty application[J].IEEE Transactions on Control Systems Technology,2006,14(4):641-653.
[13]石秀勇,罗亨波,倪计民,等.基于模型的柴油机urea-SCR系统闭环控制策略仿真[J].内燃机学报,2017,35(4):346-353.SHI X Y,LUO H B,NI J M,et al.Model-based closed-loop control strategy of diesel urea-SCR system simulation.[J].Transactions of CSICE,2017,35(4):346-353.
[14]WATLING T C,TUTUIANU M,DESAI M R,et al.Development and validation of a Cu-zeolite SCR catalyst model[C/OL].SAE Paper,2011,2011-01-1299.(2011-04-12).https://doi.org/10.4271/2011-01-1299.
[15]臧志成,朱磊,陈凌云.DPF喷油助燃主被动再生系统电控单元开发[J].内燃机工程,2016,37(5):74-79.ZANG Z C,ZHU L,CHEN L Y.The electronic control unit development of fuel injection combustion active and passive DPF regeneration system[J].Chinese Internal Combustion Engine Engineering,2016,37(5):74-79.
[16]KOTRBA A,GARDNER T P,BAI L,et al.Passive regeneration response characteristics of a DPF system[C/OL].SAE Paper,2013,2013-01-0520.(2013-04-08).https://doi.org/10.4271/2013-01-0520.
[17]李弘扬,蔡忆昔,施蕴曦,等.负荷对柴油机微粒捕集器再生的影响[J].内燃机工程,2016,37(6):200-204.LI H Y,CAI Y X,SHI Y X,et al.The effect of engine load on diesel particulate filter regeneration[J].Chinese Internal Combustion Engine Engineering,2016,37(6):200-204.