柴油机SCR系统的故障诊断与排除

On Malfunction Diagnosis and Removal of Diesel Engine's SCR System

以某公司所生产的满足国四排放标准的气助式柴油机选择性催化还原(SCR)系统为对象,研究了该系统的组成、工作原理和故障诊断方法,分析了主要总成的故障原因,常见的故障现象包括:SCR系统断开故障,传感器故障,排气温度传感器故障,计量泵故障,尿素液位高度没有变化故障,尿素罐温度传感器故障,并提出了故障诊断流程和排除方法。

Taking the tail gas purifying system of diesel engine' s selective catalytic reduction technology( SCR) as the research object,this paper studies the formation,working principles and ways of malfunction diagnosis of the SCR system produced by a company,which has met the National IV emission standard. Then it analyzes the main reasons for the malfunction as follows: disconnect; sensing elements breakdown; discharge temperature of sensing elements; metering pump breakdown; urea level breakdown; temperature sensing breakdown of urea tank. It finally puts forward a procedure for malfunction diagnosis and method of removing the malfunction.