Engine fault diagnosis and detection is inseparable from the analysis and examination of each sensor or actuator, and the waveform display is the most intuitive and convenient way. This system is an engine waveform tester developed based on virtual instrument and the batch estimate fusion theory is used in the process of the single sensor data acquisition and processing. It is proved by practice that this instrument can conveniently and quickly realize the functions such as signal acquisition and control, waveform analysis and processing and result expressing and output, thus providing technical support for comprehensive intelligent engine fault diagnosis technology.

The fault data of 133 Xiali taxis in Xingtai Car Rental Company are collected and the preliminary sorting is conducted to them. The automobile preventive repair model is established and the analysis of the necessity and feasibility of preventive repair is performed. In the base of reliability analysis of fault data, the failure rule is obtained and the optimal repair cycle is found out.