Realization Of Communication Protocol And Fault Management For New Energy Automobile ECU

The development of new energy vehicles is an important measure to boost the strategic transformation of the traditional auto industry and build a resource-conserving and environment-friendly society. Compared with the traditional vehicle, the electronic control system of the new energy vehicle is more complex and the correlation between the electronic control units is closer, which brings the necessary of the real-time data communication. CAN bus, which has high communication speed and anti-interference performance, is usually used to provide a uniform information transmission channel for the ECU. However, the CAN protocol only defines the connection principle of physical and the data link layer without the definition of the physical meaning of data. To create a complete communication system, each control device needs to conform to the uniform standard to accomplish the communication and analysis of data. Therefore, this paper uses the SAE J1939 protocol to develop a uniform standard for data. SAE J1939 protocol stack, which can reduce the complexity of the communication protocol transplantation and improve the efficiency of the ECU development, has been deeply researched and designed for the new energy vehicle. Meanwhile, the management and communication of the fault information also have been studied in this paper, which can reduce the probability of fault leakage and improve the reliability of the fault system.First of all, the J1939 SAE communication protocol standard is briefly introduced. Then SAE J1939 communication protocol has been realized in the form of protocol stack. The SAE J1939 protocol stack is composed of hardware abstraction layer, data link layer, transport layer, network management layer, application layer and diagnosis. The hardware abstraction layer is directly driven by the CAN module of hardware system, which is convenient for the communication protocol stack to be transplanted in different hardware systems.Secondly, the SAE J1939 communication protocol stack was integrated in the measurement system of computer and the rapid prototyping of electronic control unit(RP-ECU) in form of middleware. The RP-ECU was designed based on multi-core microprocessor F28M35 x. The measurement system of computer is composed of the monitoring interface, the database, the CAN drive module and the J1939 SAE communication protocol. In addition, the hardware system and software system of RP-ECU are introduced in this paper. The hardware structure and software driver of CAN module of F28M35 x are designed.Thirdly, the management and communication of fault information, which is based on multi-core processor, have been studied. The management of fault information includes the communication mechanism between control nuclear and communication nuclear, confirmation of fault information, the management of fault path, the design of fault storage and the communication of fault information.Finally, the system test platform, which has been used to test the SAE J1939 communication protocol and fault management, was built according to the application examples of the new energy vehicle. According to the experiment test, the real-time data transmission can be realized by the SAE J1939 protocol designed in this paper. Meanwhile, the fault information can be effectively confirmed and reasonably managed by the fault management system.