【作者】 白羽；

【导师】 滕勤； 马标；

【作者基本信息】 合肥工业大学 ， 动力工程（专业学位）， 2019， 硕士

【摘要】 作为国六排放柴油机,高效率SCR是必须达到的基本要求,因此催化器的评价测试成为SCR技术应用中的一个关键环节。为了检验选择性催化还原(SCR)催化器与柴油机的匹配情况以及对SCR催化器进行单体评价测试,构建柴油机后处理装置试验评估系统,开发尿素喷射控制系统。尿素喷射控制系统由基于16位微控制器开发的控制单元和后台管理系统组成。控制单元根据上位机设定的目标值,采用双闭环控制方式控制喷射压力。主要研究内容如下:测控系统硬件设计。从测试试验要求出发,分析试验被测对象工作原理和配置需求。使用飞思卡尔16位微控制器完成硬件系统设计,主要包括控制单元最小系统设计、供电模块设计、执行器驱动电路设计、通讯模块设计和传感器信号调理电路设计。测控系统软件设计。以CodeWarrior为开发工具编写各硬件模块驱动程序和主程序。主程序采用结合了大循环扫描、中断触发和节拍触发的前后台架构,包含喷射系统状态切换程序、尿素泵压力控制程序、尿素喷嘴控制程序和电加热控制程序。测控系统后台管理软件设计。基于VB.NET编译环境开发后台管理软件,后台管理软件与下位机相互通信完成尿素喷射系统的加载和系统状态显示。主要功能包括登录用户管理、系统参数设计、尿素喷射速率加载、数据处理以及系统状态监控。利用后台软件测试尿素喷嘴与尿素泵特性,标定尿素喷嘴和尿素泵控制参数。测控系统台架功能验证。利用后处理系统性能评价试验装置的排温和排气流量控制子系统保障工况条件,并利用排放测量设备测量NO_X和氨泄漏,进行空速扫描、温度扫描和氨氮比扫描试验。借助标定试验确定的控制特性,在发动机台架上对尿素喷射控制系统进行功能性和可用性检验,并测试评价催化器性能。结果表明,尿素喷射控制系统完全能够满足后处理单体测试和催化器效率评价测试的要求。更多还原

【Abstract】 For China Ⅵ Emission Standard,high-efficiency SCR is a basic requirement that must be met,so the evaluation experiment of catalytic converter is important in the application of SCR technology.In order to test if the selective catalytic reduction(SCR)catalytic converter matches the diesel engine and the monomer evaluation test of the SCR catalytic converter,a diesel engine aftertreatment device test evaluation system was constructed to develop a urea injection control system.The urea injection control system consists of a control unit and a background management system which is developed based on a 16-bit microcontroller.The control unit controls the injection pressure by means of double closed-loop control and the target pressure is given by host computer.The main research contents are as follows:Hardware design of measurement and control system.Analyzing the working principle and configuration requirements of the test object according to test requirements.The hardware system design is completed by using Freescale’s 16-bit microcontroller,including the minimum system design of the control unit,power supply module design,actuator drive circuit design,communication module design and sensor signal conditioning circuit design.Software design for measurement and control system.Coding each hardware module driver and main program with CodeWarrior.The main program uses a front-end architecture that combines large loop scans,interrupt triggers,and beat triggers.The main program consists of the injection system state switching program,the urea pump pressure control program,the urea nozzle control program,and the electric heating control program.The background management software design of the measurement and control system.The background management software is developed based on the VB.NET compiler environment.The background management software communicates with the host computer to load and display the urea injection system status.The main functions include user login management,system parameter design,urea injection rate loading,data processing,and system status monitoring.The background software is used to test the characteristics of the urea nozzle and the urea pump,then the urea nozzle and urea pump control parameters were calibrated.verification of the test and control system bench function.The exhaust temperature and exhaust flow control subsystem of the post-treatment system performance evaluation test device guarantees the working conditions,and the test device detect NOx and ammonia leakage using emission measuring equipment and performs airspeed scanning,the put on temperature scanning and ammonia-nitrogen ratio scanning test.The function and usability of the urea injection control system was tested on the engine rig with the help of the control characteristics determined by the calibration test,and the performance of the catalyst is then evaluated.The results show that the urea injection control system can fully meet the requirements of post-treatment monomer test and catalyst efficiency evaluation test.更多还原