Study On Fault Tolerance Strategy For Hybrid Electric Vehicle

In order to make Hybrid Electric Vehicle(HEV) work safely, smoothly and efficiently under the error status of the power elements, this paper focus on the fault tolerant strategy research in the HEV.Firstly, the structure of the full HEV is introduced, including the periphery input circuit of Hybrid Control Unit(HCU). Considering the complexity and diversity of vehicle control system, the vehicle CAN is designed and the performance simulation analysis of CAN is carried.The introduction of fundamental functions of ECUs laies foundation for the next fault analysis.On the fault diagnosing and tolerance strategy, the faults are divided into three parts: the systematical faults, the CAN communication faults and the fault signals of ECUs transmiting through CAN. Through the principle analysis of sensors, acutators and CAN, the fault diagnosis model is established, According to the ISO26262 standard, the HCU can make a fault grade when the fault appears, and the fault tolerant strstegy is proposed. According to different fault grade, tolerance strategy is divided into four fault processing modules: slight with error, reduce power, limp home, stop engine and power off.Ultimately, on the testing platform of hardware in loop(HIL), the proposed validity of fault diagnosis strategy is execued by the faliure injection method. On the rapid control prototype platform, the validity of fault tolerant strstegy is execued on the bench, through the dates analysis, the dealing strategy is reasonable.