Research On Key Technology Of CAN Network Design And Development Of Hybrid Electric Bus

Global energy crisis and environmental pollution, make us to reach such a consensus: the car, to energy saving, but also to environmental protection.Concerning the national policy to encourage and market, new energy automobile promotion drives more and more attention from all sectors of society. City bus is a national priority development of new energy automotive products. Hybrid system, is currently the most adapted to the operating mode of the urban public passenger car dynamic system configuration. High quality communication in vehicle CAN network is a necessary condition for hybrid electric vehicle power train normal work.In this paper, we focus on the development of hybrid electric bus CAN network system, and focus on the network topology, communication protocol, network design and simulation, etc., taking a hybrid electric vehicle as the research object,the key technology of CAN network design and development of hybrid electric bus is studied.First of all, according to the demand of hybrid electric vehicles, the vehicle network architecture and protocol are designed, which is suitable for the research of the model. Based on the J1939 protocol, the system structure and the main assembly parts of hybrid electric vehicles, the vehicle network architecture, and a detailed and complete CAN protocol are done. Using CANoe network simulation software,including network load, error frame test and other functions, the development of the network simulation 、testing and optimization are done.Based on the above CAN network, the coordination control problem in the practical application of the hybrid power bus management system is solved. CAN network delay on dynamic assembly coordination control effect analysis, hybrid power system of the engine idling start stop function control logic implementation,to solve the different network nodes of the vehicle network protocol packet collision etc..In order to solve the problems of electromagnetic interference in theelectromagnetic interference of the electric motor and other components in the hybrid system, the CAN network information error sending and receiving is optimized. The layout of the network is designed, which is combined with the CAN.The reasonable frequency of packets is selected, and the accurate execution of the hybrid bus powertrain control strategy and the efficient and reliable transmission of CAN packets in the complex CAN networks are ensured.In order to solve hybrid system in electric motors and other components for electromagnetic interference resulting in can network error message sending and receiving, electrical components of the interface and the structure of the design are analyzed, optimized for network layout, sending settings. Design a combination of straight and hierarchical network layout, select reasonable frequency of can message,to ensure that the hybrid electric vehicle power assembly control strategy of exact execution and can message in hybrid bus complex network can be efficiently and reliably sent and received.In the end, the main problems and targets of the hybrid electric bus communication quality evaluation are put forward, based on the research of hybrid electric bus and simulation experiment platform. In this paper, a new CAN network communication quality evaluation index including bus network error frame, load ratio, trunk and branch line length, can effectively test the communication quality of the development system, which provides the basis for the development, test and optimization of hybrid CAN network.In this paper, the CAN network architecture and protocol of hybrid electric city bus are completed, and the problems of network coordination control,electromagnetic interference and communication quality evaluation are solved.