摘要
在国Ⅵ柴油机主流箱式和筒式后处理器上验证下游NO_(x)是否满足测量准确度要求.结果表明:布置在箱式后端面上的下游NO_(x)传感器满足测量准确度要求;布置在筒式后锥面上的下游NO_(x)传感器则不满足.筒式结构仿真结果表明:后锥面位置氨浓度均匀性为0.957,但是后锥面中心位置氨浓度局部较高,不能满足NO_(x)测量准确度要求;氨浓度分布在尾管直管上的均匀性大于0.970,且氨浓度局部高所占的面积随尾管长度增加而逐渐减小.位置优化试验结果表明:将下游NO_(x)传感器位置由锥面改为尾管直管段,且NO_(x)传感器布点距筒式后处理锥截面最小距离为190 mm左右时,满足下游NO_(x)测量准确度要求.设计一种后腔混合器,使当前下游NO_(x)传感器位置氨浓度均匀性仿真结果为0.996,且无氨浓度局部高的问题,此方案同样可解决下游NO_(x)测量准确度问题.
NO_(x) measurements downstream of diesel engine aftertreatments respectively with box shape and barrel shape were carried out to verify whether the NO_(x) sensor meets accuracy requirements of the ChinaⅥemission standard.The experimental results show that the NO_(x) measurement accuracy is achieved when the NO_(x) sensor is arranged on the rear surface of the box shaped aftertreatment,while that is not achieved when the NO_(x) sensor is located on the rear cone of the barrel shaped aftertreatment.The simulation results for the barrel shaped aftertreatment show that the ammonia concentration distributed on the rear cone surface has a uniformity degree of 0.957,but the ammonia concentration in the central location of the rear cone surface is locally high,which does not meet the NO_(x) measurement accuracy requirements.The ammonia concentration distribution in the straight section of the tail pipe has a uniformity degree of greater than 0.970,and the local area with high ammonia concentration is gradually decreased with the increase of the length of the tail pipe.Sensor location test results show that the NO_(x) measurement accuracy can be achieved when the sensor location is moved from the tapered surface to the straight pipe section of the tail pipe and has the minimum distance of 190 mm to the cone of the barrel shaped aftertreatment.A post-cavity mixer was then designed and is found that it can increase the ammonia concentration uniformity to 0.996 when measured at the current NO_(x) sensor location and there is no local high ammonia concentration problem.The issue of the NO_(x) measurement accuracy downstream of the exhaust aftertreatment is solved.
作者
袁志玲
耿磊
张建华
卞增涛
张希杰
Yuan Zhiling;Geng Lei;Zhang Jianhua;Bian Zengtao;Zhang Xijie(State Key Laboratory of Engine Reliability,Weichai Power Company Limited,Weifang 261061,China;Engine Research Institute,Weichai Power Company Limited,Weifang 261061,China;Weichai Power Air Purification Technology Company Limited,Weifang 261061,China)
出处
《内燃机学报》
EI
CAS
CSCD
北大核心
2021年第2期186-191,共6页
Transactions of Csice
关键词
柴油机
NOx传感器位置
国Ⅵ排放后处理器
箱式和筒式
diesel engine
NOx sensor location
ChinaⅥexhaust aftertreatment
box shape and barrel shape
