CAN总线在大中型客车中的应用

pplication in the large-and-middle-scale passenger train of CAN bus

大中型客车是指车长超过7米的客车,它主要用于旅游、长途客运以及城市公交等领域。由于随着安全环保节能要求的不断提高,以及车内服务设施的逐渐增多,电控系统的复杂程度也不断提高,更严重的是传统的那种点对点的控制方式造成了庞大的布线系统,加剧了粗大的线束与汽车有限空间之间的矛盾,使得整车电气的可维护性降低,可靠性下降。CAN总线在高档轿车上的应用已充分体现了它在解决这些问题上的优势,在客车上的应用也符合汽车产品向电子化、模块化、智能化的发展趋势。另外国家交通部在《营运客车类型划分及等级评定》明确要求,特大、大型高三、高二级的客车"在底盘动力总成间配置CAN总线",也为公司的大中型客车的电控系统进行CAN改造提出了要求。文章首先介绍了传统大中型客车的电控体系结构和技术特性,并分析了其优缺点,进而提出了大中型客车电控系统CAN总线的网络结构。并对网络中的每个节点进行电路设计,编制软件。节点CPU采用ATMEL公司生产的专为CAN应用的AT89C51CC03,接口元器件主要采用Motororal针对汽车电子开发的器件。由于国家对汽车的电磁骚扰方面的要求,文章对基于CAN总线的电控系统的抗电磁干扰方案进行了探讨。

Large and medium size car refers to the mainly utilized car longer than 7m, for tourism, long passenger which is distance transportation and city mass transportation etc.. With gradually elevated requirements on safety, environment protection and energy efficiency, and increasing quantity of onboard service devices, the electric control system is getting more and more complicated. Wore seriously, the traditional ＂peer to peer＂ control mode generates huge wiring network, which sharpens the contradiction between thick wire bundles and limited inner space of the car. Further more, it deteriorates the serviceability and reliability of electric system of the car. The application of CAN bus in high end Sedan has shown its advantages on solving foregoing problems. Its application on the passenger car complies with the development tendency on electronization, modulization and intellegentization of automobile products. Plus, as required by ＂classification and grade assessment of operational passenger cars＂（JT/T325-2004） issued by National Communication Ministry, the Super-large, Large high grade Ill and II cars ~must integrate CAN bus in power assembly of chassis~, which raised the demand of CAN retrofit in electric control system of company＇s large and medium size passenger cars. As one of the important development trends of automobile control system, onboard control network must have better real-time response ability and error compatibility. On the basis of comprehensive analysis of the current situation and development trend of electric control system for large and medium size passenger car, and reference of CAN bus system generally adopted in Sedan, this thesis presents the study of the CAN retrofit of large and medium size passenger cars, and the solution. At the beginning of the thesis, it introduced the configuration and technical characteristics of the traditional electric control system adopted by large and medium size cars. Then, based on the analysis of its advantages and shortcomings, evolved the network configuration of CAN bus system for large and medium size passenger cars. Also, in the thesis, it included the circuit design and software program for each node of the network. The node CPU is AT89C51CC03, which is made by ATMEL specially designed for CAN application, while the interface elements are produced by MOTORORAL for automobile electronic purpose. As government has special requirement on automobile electromagnetic interference, this thesis also discussed the anti-electromagnetic interference solution for electric control system based on CAN bus.