柴油机排气氧化催化转化器(DOC)是一种重要的柴油机排气后处理技术,其在线故障诊断是柴油车车载诊断系统(OBD)的重要内容之一.根据DOC在线故障诊断技术研究的需要,采用仿真分析方法对以DOC前后排气温度和排气背压作为DOC催化剂老化、载体堵塞以及破损等失效故障诊断参数的在线诊断方案进行了分析.研究结果表明:在一定柴油机工况下,以DOC前后排气温度和排气背压结合一定的诊断算法对DOC的失效故障进行诊断是可行的.
The diesel oxidation catalyst (DOC) is one of the important diesel exhaust after-treatment techniques, and the online fault diagnosis technique of DOC is one of the important contents of diesel vehicle OBD system. In this paper, the online fault diagnosis plan using the temperature and pressure before and after DOC as the fault diagnosis character parameters of DOC was analyzed by using the simulation method. The results show that on some diesel operation conditions, it is possible to diagnose the faults of the DOC by using the temperature and pressure before and after DOC combining with certain diagnosis arithmetic.