柴油机排气后处理系统CRT故障诊断研究

摘要

Taking the exhaust after-treatment system CRT (Continuously Regenerating Trap) of diesel engine as the research object ,the simulation model of GT-Power was established and verified by com-paring bench test data and simulation data .The fault simulation was carried out to analyze the influ-ence of different degrees of damage and blockage on temperature and pressure difference between two ends of DOC (Diesel Oxidation Catalyst) and CDPF (Catalytic Diesel Particulate Filter) ,The results show that the fault is sensitive to the pressure difference .Based on pressure difference ,the parameter K was proposed as the fault diagnosis parameter of CRT system and the working condition has little effect on parameter K .Under the steady state and NEDC cycle ,it is proved that the parameter K is sensitive to the damage and blockage of CRT system .K can be used to judge the fault degree and fault types .%以柴油机排气后处理系统连续被动再生颗粒捕集器(CRT)为研究对象,建立GT-Power仿真模型,通过对比台架试验数据与仿真数据验证了模型的准确性.通过故障仿真,分析了氧化催化器(DOC)和催化型颗粒物捕集器(CDPF)不同程度的破损与堵塞对其两端温差和压差的影响.结果表明,压差参数对故障较为敏感.基于压差提出了参数K作为CRT系统的故障诊断参数,工况对参数K影响较小,在稳态和NEDC循环下验证了该参数对CRT系统破损和堵塞故障敏感,通过参数K能够判断出故障程度及破损、堵塞等故障类型.