摘要
针对现有的选择性催化还原系统容积式尿素泵尿素液供给间断对喷嘴喷射特性产生的影响,以及在泵体、喷嘴等部位残留尿素液易导致结晶等问题,设计了一种胶囊式气动尿素泵,并介绍了胶囊泵的结构与工作原理。胶囊泵通过设置泵内腔结构,使其在出液单向阀开启时,胶囊外腔向喷嘴与泵内腔同时供给尿素液;当出液单向阀关闭时,由泵内腔向喷嘴供给尿素液,确保了尿素液周期性连续供给。同时,通过控制电磁阀启闭对胶囊泵气路进行调节,实现了泵体、喷嘴等处残留尿素液回收。对胶囊泵在一个周期内,胶囊外腔排出尿素液总体积V、以及喷嘴、泵内腔分别排出尿素液体积V,V进行了理论计算与分析,并探究了胶囊泵排量特性,分析结果表明胶囊泵的排量V与占空比D成正比,通过设置占空比D即可对其排量V进行线性调节。其次,借助AMESim仿真平台对胶囊泵进行了仿真模拟,深入探究了电磁阀在不同频率f及占空比D时对胶囊泵的响应特性与流量特性的影响。最后,通过试验验证了胶囊泵的流量特性与供给精度,试验结果表明,胶囊泵具有良好的流量调节特性与喷射精度,在占空比10%~80%区间,其供给精度为±5%,质量流量可以在7~56 g/min范围内线性调节,能够满足选择性催化还原系统在不同工况的使用需求。
In view of influence of intermittent urea supply of the positive displacement urea pump for the existing selective catalytic reduction(SCR) system on the nozzle injection characteristics,and the urea crystallization caused by the residual urea in the pump body and nozzle,a capsule pneumatic urea pump(CPUP) was designed,and the structure and working principle of the CPUP were introduced. By setting the inner cavity structure of the CPUP,the outer cavity of the capsule supplies urea to the nozzle and the inner cavity of pump at the same time when the outlet check valve is opened,and the inner cavity of pump continuously supplies urea to the nozzle when the outlet check valve is closed,which ensures the periodic and continuous supply of urea.At the same time,the gas circuit of the CPUP is adjusted by controlling the opening and closing of the solenoid valve,which realizes the recovery of residual urea in the pump body and nozzle.The total volume Vof urea discharged from the outer cavity of capsule,and the volumes Vand Vof urea discharged from the nozzle and the inner cavity of pump in one cycle were theoretically calculated and analyzed respectively. The displacement characteristics of the CPUP were studied.The results show that the displacement V is directly proportional to the duty cycle D,and the displacement V can be linearly adjusted by setting the duty cycle D.Furthermore,the CPUP was simulated by AMESim simulation platform,and the influence of solenoid valve on the response characteristics and flow characteristics of the CPUP at different frequency f and duty cycle D was deeply explored. Finally,the flow characteristics and supply accuracy of the CPUP were verified by experiments.The test results show that the CPUP has good flow regulation characteristics and supply accuracy.In the range of duty cycle 10%~80%,the supply accuracy of the CPUP is ±5%,and the mass flow of the CPUP can be adjusted linearly in the range of 7~56 g/min,which can meet the use requirements of SCR system under different working conditions.
作者
杨凯
廖昱
李莎
张达
林晨
YANG Kai;LIAO Yu;LI Sha;ZHANG Da;LIN Chen(School of Physics and Mechanical&Electrical Engineering,Hubei University of Education,Wuhan 430205,China;Institute of logistical Intelligence,Hubei University of Education,Wuhan 430205,China;School of Mechanical Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,China;Shentuo(Beijing)Science&Technology Co.,Ltd.,Beijing 100023,China)
出处
《流体机械》
CSCD
北大核心
2022年第10期54-60,共7页
Fluid Machinery
基金
湖北省教育厅科学技术研究计划项目(B2020175)。
关键词
选择性催化还原
尿素结晶
胶囊式气动尿素泵
流量特性
供给精度
selective catalytic reduction
urea crystallization
capsule pneumatic urea pump
flow characteristics
supply accuracy
