摘要
在一台1.5 L涡轮增压缸内直喷汽油发动机上,使用不同的三效催化反应器(three-way catalytic,TWC)、稀燃NO_(x)捕集器(lean NO_(x)trap,LNT)、被动选择性催化还原器(passive selective catalytic reduction,PSCR)等排气后处理组合,研究了汽油发动机稀薄燃烧下不同NO_(x)后处理催化器性能。试验工况为基于该发动机在某车型的世界统一轻型车测试循环工况的14个聚类点。结果表明,稀薄燃烧能有效降低有效燃油消耗率,部分负荷下可减少3.1%~10.1%。稀燃模式下,过量空气系数每增加0.1,NO在NO_(x)总量中占比降低6.9%;浓燃模式下,总体趋势上,TWC前的NO体积分数每增加100×10^(-6),NH_(3)增加48×10^(-6);过量空气系数0.95时,TWC的NO-NH_(3)转化率在51%~74%之间;TWC+LNT+PSCR能有效提高浓稀工况切换时稀燃模式运行时间;稀燃工况,LNT能促进NO氧化成NO 2,提高NO 2比例,提高PSCR的催化效率。
A 1.5 L turbocharged direct injection gasoline engine was used to study the performance of different NO_(x)after-treatment methods in lean burn gasoline engine with different combinations of three-way catalytic(TWC),lean burn NO_(x)trap(LNT)and passive selective catalytic reduction(PSCR).14 operation conditions were selected according to worldwide harmonized light vehicles test cycle(WLTC).The results show that lean burn can effectively reduce the effective fuel consumption of gasoline engine by 3.1%~10.1%on part load.In lean burn mode,the proportion of NO in total NO_(x)decreases by 6.9%for more 0.1 increase of lambda.In rich burn mode,for more 100×10^(-6)increase of NO in volume fraction before TWC,NH_(3)increases by 48×10^(-6).The NO-NH_(3)conversion rate of TWC is in 51%~74%range at lambda 0.95.TWC+LNT+PSCR can effectively improve the lean burn operation time when rich burn mode is switched to lean burn mode.In lean burn mode,LNT can promote the oxidation of NO to NO 2,increase the ratio of NO 2,and improve the catalytic efficiency of PSCR.
作者
李钰怀
张凯
罗亨波
李薛
杜家坤
陈泓
LI Yuhuai;ZHANG Kai;LUO Hengbo;LI Xue;DU Jiakun;CHEN Hong(State Key Laboratory of Engines,Tianjin University,Tianjin 300072,China;Research&Development Center,Guangzhou Automobile Group Co.,Ltd.,Guangzhou 511434,China)
出处
《内燃机工程》
CAS
CSCD
北大核心
2021年第5期79-85,共7页
Chinese Internal Combustion Engine Engineering
基金
国家科技部重点项目(2017yFB0103300)。
