| In recent years, the environmental and energy issues have become increasinglyprominent. Hybrid electric vehicle (HEV), which is energy saving and environmentalprotection, has got considerable development under the present technology conditions.Since HEV is a complex electromechanical system, its potential failures are morecomplicated than traditional vehicle. In addition, HEV has high-voltage systems,which demands stricter safety requirements. To detect faults of HEV accurately andtimely, conduct fault tolerant control reasonably, and improve the safety of HEVeffectively, a fault diagnosis algorithm for HEV is proposed in this paper.First, this paper studies the overall scheme of HEV fault diagnosis based on theconfiguration and control strategy of a domestic HEV. Then the items of faultdetection are analysised according to the characteristic of HEV, and the application ofusing logic threshold algorithm, fuzzy logic algorithm and fuzzy neual networkalgorithm for fault detection of HEV are introduced by giving examples. To ensurethe accuracy of fault detection, a fault confirmation mechanism based on timer andcounter is proposed. After fault detection and confirmation, a fault-tolerant controlalgorithm on signal level, components level and system level is studied. And anintegration program of energy management strategy and fault tolerance control onthese three levels is given. Finally, hardware in the loop test is conducted to simulatethe typical fault by fault injection. The experiment results show that the proposedalgorithm can detect failures accurately and timely, and take the reasonable tolerantcontrol to ensure safety of the HEV. Meanwhile, it can output the correct fault codes.The proposed algorithm can detect faults promptly and accurately, and it can takea reasonable fault tolerant control to ensure the vehicle safty. Some of the keyalgorithms have been applied to a domestic HEV. The application shows that theproposed diagnosis algorithm has certain significance. |
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