Control Change Cause Analysis-Based Fault Diagnostic Approach

How to identify the fault causes quickly and improve the efficiency of maintenance, which can reduce the fault disaster, has always been one of the key problems in equipments fault diagnosis. In this paper, a new qualitative fault diagnostic approach based on control change cause analysis (3CA) is proposed to identify the fault causes and fault risk index, which can be utilized to control the risk of equipment fault. We employed an existing method that was events and conditional factors analysis (ECFA+) to identify the analysis objects of 3CA, and put forward integrated methods including first principle-best practices approach, barrier failure analysis and prioritization rating code (PRC) matrix to accomplish control analysis, change analysis and significance rating of 3CA respectively, and those technical methods could be used to build the procedure diagram of identifying the content in each column of 3CA worksheet. According to the procedure of 3CA, we built a worksheet of 3CA for a vehicle engine fault, then fault causes and significance rating on behalf of the rating of fault risk index were determined. Meanwhile fault risk index had also been used to rank the fault causes, accomplishing fault diagnosis and verifying the availability or this method for fault diagnosis. The proposed approach can be able to identify fault causes of different fault modes that they have different risk index, and provide the fault causes rating that is the foundations of troubleshooting, which can mitigate and control fault disaster.