文档摘要:目前,城市车辆低负荷运行工况占比较多,但较容易被忽视.为深入探究低负荷循环(LowLoadCycle,LLC)排放特性与其他循环的差异,基于重型柴油发动机开展台架排放试验.通过运行LLC、全球统一的瞬态循环(WorldHarmonizedTransientCycle,WHTC)、中国发动机瞬态循环(ChinaHeavy-dutyTransientCycle,CHTC)试验循环,测取NOx、碳氢化合物(Hydrocarbon,HC)和CO排放体积分数及颗粒数(ParticulateNumber,PN)排放因子数据,并对比上述3种循环的工况特征、负荷分布、比排放量结果,分析上述循环的高排放工况分布特征,进而对比LLC循环冷热态工况排放特性差异.结果发现:该发动机运行LLC循环时,怠速以及当转矩在400N·m以下、转速为1600~2200r/min时的工况点比其他循环分布更多,0~5%负荷区间分布占比更高;LLC循环热态NOx比排放量为1572.13mg/(kW·h),LLC循环和CHTC循环工况对于NOx排放的要求更为严格,LLC循环的排气温度总体相对偏低;冷态条件使得低负荷、低转速工况的NO,排放增加量尤为明显;LLC与CHTC循环的PN高排放现象主要出现在0~10%负荷区间,CHTC循环在50%~60%负荷区间也存在高排放峰值,WHTC循环PN高排放总体分布相对较为平均;LLC循环的低排气温度会对选择性催化还原(SelectiveCatalyticReduction,SCR)转化效率产生负面影响,且冷启动条件下会进一步加剧,使得NO,排放水平远超WHTC和CHTC循环.
Abstract:Lowloadconditionsofurbanvehiclesaccountforalargeproportionofreal-worlddrivingsituations,buttheyareeasilyoverlooked.TofurtherinvestigatethedifferencesinemissioncharacteristicsbetweenLowLoadCycles(LLC)andothercycles,emissiontestsontheenginebenchusingaheavy-dutydieselenginewereconducted.Atfirst,LLC,WorldHarmonizedTransientCycle(WHTC),andChinaHeavy-dutyTransientCycle(CHTC)testswereperformedonebyone.Enginespeedandtorqueweremeasuredbyadynamometer.VolumefractionsofNOx,Hydrocarbon(HC),andCOweremeasuredthroughadirectemissionanalyzer.EmissionfactorsofPNweremeasuredbyaParticulateNumber(PN)counter.Secondly,thespecificemissionvalueswerecalculatedaccordingtothemethoddescribedintheChinaⅥstandard.Then,speed-torquedistributioncharacteristics,loaddistributionpatterns,anddifferencesinspecificemissionresultsofthethreecyclesmentionedabovewerecompared.Additionally,afterselectingdatapointsforhigh-emissionconditions,thehigh-emissionconditiondistributioncharacteristicsoftheabovecycleswereanalyzed.Finally,theemissioncharacteristicsoftheLLCcycleundercoldandhotstartconditionswerecompared.TheresultsshowthatwhentheenginerunsLLCcycle,thedatapointsinidlespeedand1600-2200r/minbelow400N·maremoredistributedthanthoseinothercycles,andthedistributionofloadrangeof0-5%ishigher.TheNOx-specificemissionresultofthehotLLCcycleis1572.13mg/(kW·h),andtherequirementsforNOxemissionsaremorestrictlyundertheLLCcycleandCHTCcycleconditions.TheoverallexhausttemperatureoftheLLCcycleisrelativelylow.ThecoldstartconditionsresultinaparticularlysignificantincreaseinNOxemissionsunderlowloadandlow-speedrange.ThehighPNemissionsofLLCandCHTCcyclesmainlyoccurinthe0-10%loadrange,whiletheCHTCcyclealsohashighemissionpeaksinthe50%-60%loadrange,andtheoveralldistributionofPNhighemissionsintheWHTCcycleisrelativelyaverage.ThelowexhausttemperatureoftheLLCcycleharmstheSelectiveCatalyticReduction(SCR)conversionefficiency,anditfurtherintensifiesundercoldstartconditions,resultingintheNOxemissionleveloftheLLCcyclefarexceedingtheleveloftheWHTCandCHTCcycles.
作者:王凤滨 廖清睿 周涛 于晓洋 车金涛 Author:WANGFengbin LIAOQingrui ZHOUTao YUXiaoyang CHEJintao
作者单位:天津大学内燃机燃烧学国家重点实验室,天津300072;中国汽车技术研究中心有限公司,天津300300中国汽车技术研究中心有限公司,天津300300广西玉柴机器股份有限公司,广西玉林537000
刊名:安全与环境学报 ISTICPKU
Journal:JournalofSafetyandEnvironment
年,卷(期):2024, 24(6)
分类号:X82
关键词:环境工程学 柴油发动机 低负荷循环(LLC) 瞬态循环 氮氧化物 颗粒数
Keywords:environmentalengineering dieselengine LowLoadCycle(LLC) transientcycle nitrogenoxides particulatenumber
机标分类号:TK421.5U464.172P4
在线出版日期:2024年7月4日
基金项目:广检中心重点项目重型柴油机LLC循环与其他瞬态循环排放特性的对比分析[
期刊论文] 安全与环境学报--2024, 24(6)王凤滨 廖清睿 周涛 于晓洋 车金涛目前,城市车辆低负荷运行工况占比较多,但较容易被忽视.为深入探究低负荷循环(LowLoadCycle,LLC)排放特性与其他循环的差异,基于重型柴油发动机开展台架排放试验.通过运行LLC、全球统一的瞬态循环(WorldHarmonizedTr...参考文献和引证文献
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关键词:环境工程学,柴油发动机,低负荷循环(LLC),瞬态循环,氮氧化物,颗粒数,
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