2017年1月1日起国家分阶段实施国5排放标准,对车用柴油机排放提出更加苛刻的环保要求。柴油高压共轨技术的普及应用,需要维修技术人员了解故障诊断原则,有清晰的诊断思路、丰富的实践经验、遵循科学的诊断方法,尽可能准确而迅速地找出故障所在。1故障诊断的基本原则1.1先外后内先外即发动机出现故障时,先对电控系统外的可能故障现象进行检查,包括发动机有无异响、发动机怠速工况 From January 1, 2017 onwards, the state implements the national emission standards in stages, putting forward more stringent environmental requirements on the emission of diesel engines for vehicles. The popularization and application of diesel common rail technology requires maintenance technicians to understand the principle of fault diagnosis, clear diagnosis ideas, rich practical experience and follow scientific diagnostic methods to find out the fault accurately and promptly as possible. 1 The basic principles of fault diagnosis 1.1 Before and after the first out of the engine failure, the first electronic control system may be the phenomenon of failure to check, including whether the engine abnormal noise, the engine idling conditions