【作者】 刘坤；

【导师】 韩永强；

【作者基本信息】 吉林大学 ， 动力工程及工程热物理， 2015， 硕士

【摘要】 柴油机发明100多年以来，因为具有较高的热效率和耐久可靠性而得到大力发展，但是柴油机的微粒（PM）排放一般要比汽油机大几十倍，成为了大气环境的主要污染源之一，且会对人体的健康产生极大的危害。因此，必须使用微粒测量系统来检测柴油机的微粒排放水平。国际上将微粒测量系统分为全流稀释微粒测量系统和部分流稀释微粒测量系统两种。因为部分流稀释取样系统体积小、成本低廉的优点而得到广泛使用，因此本课题决定在现有硬件结构的基础上研制一套部分流等动态微粒采样系统，其不仅可以测量稳态工况下的微粒排放，也具有测量瞬态工况下微粒排放的潜力。本文首先介绍了部分流等动态微粒采样系统的工作原理和比排放的计算公式，并在前期已完成硬件选型的基础上，搭建了该部分流等动态微粒采样系统。然后，本文以飞思卡尔MC9S12XS128开发板为基础，搭建了该部分流等动态微粒采样系统的控制平台。完成了对压差传感器信号、温度传感器信号以及流量控制阀位置反馈信号的采集，制定了流量控制阀和电磁阀的控制策略，并根据PID算法制定了压差稳定性控制策略。为了方便的实时监测本系统的工作状态，本文基于LABVIEW完成了该系统上位机软件的编写，并模拟了LABVIEW上位机与电控单元下位机的通讯试验，验证了上、下位机之间的通讯功能。考虑到实验室的震动、温度等因素可能会对压差传感器的测量带来影响，本文搭建了部分流等动态微粒采样系统的静态调试系统，使用变频风机模拟发动机排气，在排气测量管后方安装蝶阀模拟排气背压，模拟了不同排气流量、不同排气背压下该系统的压差稳定性，验证了该系统的可行性。在使用本课题自行研制的部分流等动态微粒测量系统测量发动机微粒排放之前，本文对PID参数进行了整定，选取了最适合该系统的PID参数。然后使用该系统对4D20发动机B50工况下的微粒排放进行了五次测量，验证了该系统测量结果的一致性，并计算了B50工况下的比排放,比排放为0.67g/kw.h。然后使用现有的微粒测量系统测量了4D20发动机B50工况下的比排放，比排放为0.61g/kw.h，并对两个系统的测量结果进行了对比，试验结果验证了该系统的适用性。最后本文根据LABVIEW编写了一款上位机通用软件，在该通用软件中，用户可以输入发动机参数，便可以得到该系统的关键参数。从而针对任何排量的发动机，用户可以选取该部分流等动态微粒采样系统的关键参数，并搭建符合自己要求的部分流等动态微粒测量系统，对该发动机的微粒排放水平进行测量。更多还原

【Abstract】 Diesel engine has developed more than100years, and because of its excellentfuel economy and durable reliability, making it as the main source of power ofautomobile and engineering machinery has been widely used. The emissions of dieselengine，s particulate is dozens of times larger than gasoline engine, and become one ofthe major sources of atmospheric environment. So carrying out the research onparticulate measurement system is imminent. International general divided particulatemeasuring system into two kinds one for full-flow dilution sampling system and theother for partial-flow dilution sampling system. Because partial-flow dilutionsampling system is small, inexpensive and then widely used. So on the basis of theexisting hardware structure, this topic decide to develop a set of partial-flow&dynamic particulate dilution sampling system. It not only can measure particulateemissions of steady state conditions, but also have the potential to measure particulateemissions of under transient conditions.First, this paper introduces the principle of partial-flow&dynamic particulatedilution sampling system and calculates the ratio of particulate emissions, then buildspartial-flow&dynamic particulate dilution sampling system. Based on FreescaleMC9S12XSP128MAL microcontroller, this paper builds the control platform ofpartial-flow&dynamic particulate dilution sampling system. I completed the dataacquisition of pressure sensors, temperature sensors, and flow control valve positionfeedback signal, designed control strategy of a flow control valve and the solenoidvalve, and based on PID algorithm designed pressure stability control policy. In orderto monitor the work of the state for the system, this paper completed the preparationof the system PC software based on LABVIEW and simulated communication testbetween PC and electronic control unit, to verify the communication function betweenthe upper and lower place machine.Considering the vibration and temperature of laboratory may have an impact onmeasuring differential pressure sensor, this paper builds the debugging system ofpartial-flow&dynamic particulate dilution sampling system. Simulates the pressure stability under different exhaust gas flow rates and different exhaust back pressure,and it verifies the feasibility of the system. In this paper, tuned the PID parameters,and select the most suitable PID parameters, then used the system measured forparticulate emissions for five times of B50conditions for4D20engine. Then verifiesthe consistency of measurements of the system and calculates the ratio emissionsunder B50conditions. Then used the existing particulate measurement systemmeasured the ratio emissions of B50conditions for the4D20engine, comparing themeasurement results of the two systems, the test results show the applicability of thesystem.Finally this paper wrote common PC software according to LABVIEW, in thiscommon software, the user can enter the engine parameters, we can obtain the keyparameters of the system. Thus for different engine, the users can select the keyparameters of the partial-flow&dynamic particulate dilution sampling system, buildpartial-flow&dynamic particulate dilution sampling system with their requirements,to measure the particulate emission levels of engines.更多还原