Development And Testing Of VCU Fault Diagnosis System For Pure Electric Vehicle

As the environmental and resource issues are increasingly prominent within the world, many countries pay more and more attention to the development of pure electric vehicles. To solve the key technical problems of EV, China has established the development of EV as an important task during the 10 th five year plan. In recent years, Chinese EV market has achieved rapidly growth, and China has become the largest country in the electric vehicle production and sale in the world.However, as all kinds of cars are released at the same time, more and more production expose the quality problems. A large number of electric cars do not have perfect fault diagnosis and processing functions, which led to the users’ experience of electric vehicles becoming worse.In this paper, based on the college_enterprise cooperation project, a pure electric vehicle controller is developed. Based on the research from home and abroad, this paper focused on the studying of the EV fault diagnosis strategy, and proposed the dual MCU hardware architecture of VCU. At the same time, to test and verify the fault diagnosis strategy, the hardware in the loop system with function of fault injection was developed, which realize VCU’s hardware in the loop test. Meanwhile, the simulation experimental platform provides a solution for the development of domestic hardware in loop system.This paper mainly studied the following aspects of content:(1) Analyze the function safety of the electric vehicle controller, and on this basis, design the hardware architecture of the vehicle controller unit. In the paper, lots of possible risks that maybe appear in VCU are analyzed and evaluated, in order to eliminate the danger on the basis of existing technology or reduce the risk to an acceptable level. Design the vehicle controller hardware architecture which conforms to the functional safety standard, and ensure that the application layer control strategy can be implemented on the hardware.(2) In the paper, the VCU fault diagnosis strategy which based on dual MCU is developed, and the control strategy of coordinated control based dual MCU is put forward. The VCU monitor the vehicle fault information constantly, and adopt different ways of response to different kinds of fault, this can ensure the vehicle achieve maximum safety degree in any time. Meanwhile, according to the vehicle state information, the VCU’s torque command will be made correction, so as to avoid failure further upgrade.(3) Develop VCU hardware in loop test platform, and perform HIL simulation for the vehicle control strategy. In the paper, the PC software of vehicle has been developed, the FIU circuit board for signal fault injection was designed. Draw up test case for HIL simulation, analyze and optimize the test cases based on the test result.(4) The VCU HIL test and real vehicle test was performed,which verify the vehicle controller control strategy of fault diagnosis, and optimize the fault process strategy based on the experimental results.