【作者】 陆勇；

【导师】 曹立波；

【作者基本信息】 湖南大学 ， 车辆工程， 2008， 博士

【摘要】 混合动力汽车作为一种新兴的节能环保型汽车,能够更充分利用和转换能源、减少污染。由于经济的持续快速增长,城市规模不断扩大,各大城市政府已纷纷将推广使用清洁燃料汽车作为净化空气和改善环境的一项重要措施。中国已经成为仅次于美国的全球第二大新车消费市场,混合动力轿车也必将在中国蓬勃发展。但由于混合动力轿车的动力电压约100～600V ,远远超过了人体的安全电压,电池发生短路、化学反应产生的有害物质或电解液泄漏均可能会对司乘人员造成伤害,这些都将影响混合动力轿车的实用前途。此外,作为交通运输工具,混合动力轿车与传统轿车存在着相同的安全问题,包括主动安全和被动安全,但混合动力轿车在增加近100kg重量的电力驱动系统后,其整车碰撞安全性能应有所改变。因此,对混合动力轿车高压电及整车碰撞安全性的研究具有重要的意义。在此背景下,开展了本论文的研究工作,取得了以下几项主要研究成果:1 ,针对混合动力轿车电池管理系统,提出了采用电压隔离开关矩阵的集中式BMS结构,并分别对电池管理硬件系统和软件系统进行设计,提高了混合动力电池管理系统的安全性、效率和抗干扰能力。在镍氢电池充放电实验基础上,详细分析了该电池充放电特性、温度特性和自放电特性。为了防止混合动力轿车在碰撞、翻车等危险工况下高压电对乘员造成伤害,创新设计了一种适应于混合动力轿车的安全电池箱。其结构简单紧凑、成本低廉、能够在电池箱受到严重挤压变形时迅速将高压电分断到安全电压。2 ,建立了某款混合动力轿车的有限元仿真模型,并分别与正面碰撞、后碰撞及侧面碰撞的实验结果相比较,验证了该整车模型的有效性。其中,探讨了该轿车侧面碰撞安全性存在问题的根源,结合侧面碰撞安全性设计普遍原则和同类车辆侧面碰撞结果的比较分析,提出了改进这款混合动力轿车侧面安全的主要措施。3 ,通过对头部损伤、颈部损伤、胸部损伤及肢体损伤基理的分析,阐述了在中国开展前碰撞损伤生物力学研究方法和方向。应用多刚体理论及MADYMO软件建立了前碰撞乘员约束系统模型,并对汽车前碰撞中乘员损伤的防护进行了深入分析。通过设计变量的筛选及应用MADYMO的软件包MADYMIZER对前碰撞乘员约束系统的性能进行了优化,提高了该混合动力轿车的前碰撞安全性。4 ,在对轿车的侧面碰撞力学特性进行分析的基础上,创新地提出了改变轿车动力仓、乘员仓和尾仓三个部分的侧向连接特性从而改进轿车的侧面碰撞性能的方法。为了验证该方法的有效性,在已验证过的混合动力轿车有限元模型基础上,通过采取减少乘员仓与动力仓及尾仓间的连接焊点数目和降低其失效准则及适当减小连接处的板件壁厚等措施,以探讨改变轿车三段之间的侧向连接强度和刚度对汽车侧面碰撞安全性的影响,并结合多刚体子结构方法对乘员损伤参数进行了仿真计算分析。结果表明,降低轿车动力仓、乘员仓和尾仓三个部分的侧向连接强度和刚度能有效地减小车门侵入量,从而有效地降低乘员胸部、腹部和骨盆的损伤参数。更多还原

【Abstract】 As a new type of vehicles in favor of energy saving and environmental protection, hybrid electric vehicles can utilize and convert the energy fully, and whereby reduce the pollution. Due to continuous and rapid growth of the economy, and the city scales take on an expanding trend, more and more major city governments will promote the use of clean-fuel vehicles as an important measure to clean air and improve the environment. China has become the world’s second largest car consumer market only after the United States, which will also make hybrid vehicles flourish in China. Also, because the power-train voltage of hybrid electric vehicle is about 100 ~ 600 V, which is far more than the safety voltage of human body, short circuit or battery electrolyte leakage is likely to cause explosions and burning. In addition, the battery chemical reaction will cause potential harm to passengers and bring new security requirements, comparing with the traditional hybrid fuel vehicles, which will also affect the application of hybrid electric vehicle in the future. As a kind of transport tool, hybrid vehicles have the same security issues as traditional fuel vehicles, and hence they should meet the same safety request with traditional fuel vehicles, including active safety and passive safety. Therefor, the research on power systems and full-scale impact safety of hybrid electric vehicle is of great significance.In this paper, some key research work has been carried out and the following main results are obtained:1. In view of research hybrid car battery management system, it brings forward one centralization BMS structure of isolated switch matrix, and the hardware and software of battery management system are also designed, which can promote systematic safety, agility, reliability and anti-jamming power of date collecting.Based on a series of charge-discharge experiments of Ni-MH battery, the characteristics of charge-discharge, temperature and local action are analyzed in detail. In order to prevent the high electric voltage hurting passengers under dangerous working conditions such as collisions, overturn and etc, a simple and compact battery box structure with low cost is designed, which is adapted to the hybrid electric vehicle and can breake high-voltage off to safety voltage quickly when the battery box is deformed severely.2. The finite element model of one hybrid car is developed and validated by comparing with the experimental results of front impact, rear impact and side impact respectively. Through in-depth analysis of the root causes of side impact safety problems, the design principles of side structural improvement and comparison with similar side impact deformation results of other car, the primary improved measures were proposed. 3. The passenger restraint system of front impact is established by using MADYMO soft, which is based on the multi-rigid body theory, and in-depth analysis of passenger injury protection have been developed too. By choice of design variables and use of MADYMIZER as optimized method, it could optimize the system performance and improve front impact safety of hybrid car.4. Based on the analysis of the mechanical characteristics of the car during side impact, this paper proposed a new method to improve the side impact safety of the car by changing the side connection characteristics of the power cabin, passenger cabin and rear cabin. In order to verify the effectiveness of the method, by using the validated hybrid car finite element model, and with decreasing the number and reducing the lapse rule of weld point and decreasing the thickness of the plates in the connection area, the side impact safety performance of the car is investigated. The passenger injury parameters are calculated by using multibody PSM method. The results show that decreasing the strength and stiffness between power cabin and passenger cabin as well as passenger cabin and rear cabin can significantly reduce the intrusion of the door. So the passenger injury parameters of chest, abdomen, and pelvic can be decreased effectively.更多还原