电动汽车电池管理系统的开发研究

本文针对电动汽车电池管理系统中的电池SOC估算和均衡电路开展研究工作。利用安时积分法设计SOC估算电路,采集电池电压进行数据分析,达到实时精确监测反馈电池SOC的功能;采用基于电感的非耗散型均衡电路控制策略,实现电池间能量均衡。在Matlab中完成了电路的仿真,通过硬件设计及电路制作验证SOC及均衡效果。结果表明,本系统能实现精确测定电池残电量和单体电池间的能量均衡,能量损耗小、工作效率高。     

莫让野蛮生长挑战公共安全 见微知著,标准先行

正目前我国电动汽车安全问题主要体现在电池使用、材料构成和充电安全方面,上下游产业发展不平衡、企业盲目重量轻质是造成这些问题的主要因素。此外,监管存在漏洞、政府相关政策不全,保障电动汽车安全必须在生产过程中严格执行安全要求和标准。随着电动汽车产业发展迈入培育的关键时期,电池等自主创新技术还有待进一步提高,如何确保电动汽车产业安全运行和健康发展成为当前面临的重大课题。据悉,为促进我国电动汽车行业标准的完     

英国某研究团队认为可以准确预测电动汽车中的电池寿命

对于汽车行业来说,提高电池性能和整体使用寿命,具有革命性意义.在英国,由两家电动汽车制造商、若干学者和一家电池分析专业公司组成的团队,正在开展一项电动汽车电池研究项目.该项目旨在预测电池寿命,据称已取得成功.     

纯电动公交车示范项目

在本项目中,临沂市公交总公司采用了铝合金全承载车身、三相异步电机驱动系统、磷酸铁锂动力电池组的纯电动车作为公交车,依靠当地电动汽车生产企业提供的车辆技术支持,从2010年2月起,先后在5条公交线路上进行了SDL6120EVG纯电动车的示范运行。通过合理使用电池、强化电池保养、加强驾驶员培训等管理手段。到目前为止,单车平均运行2万多公里,车辆运行平稳,节能环保效果良好。     

百人会电动汽车安全问题研讨会召开 提高电动汽车安全性

正3月27日,中国电动汽车百人会召开了"电动汽车热点问题系列研讨会Ⅰ",对电动汽车安全问题进行探讨和分析。目前国内电动汽车安全问题主要体现在电池使用、材料构成和充电安全方面。上下游产业发展不平衡、企业盲目重量轻质是造成这些安全问题的主要因素,此外,监管监控存在漏洞、政府相关政策不全也是原因之一。因此,电动汽车相关企业必须严抓质量环节、进行技术创新、加强监管监控、不能冒进求成;政府相关部门也应重视电动汽车安全问题,在相关政策法规上进行逐步完善,确保各部门之间协同合作,促进电动汽车行业有序、健康、稳定的发展。     

纯电动小客车用锂动力电池温度特性实验研究

本文测试和分析了纯电动小客车用锂动力电池在不同温度下的放电、充电、放电容量、欧姆内阻和表面温升性能,实验结果表明,低温对锂单体电池性能的影响比较显著,锂单体电池在低温下各项性能指标存在变差趋势。为保证锂单体电池的正常使用,建议增设电池包预加热系统以便提升锂单体电池性能。     

纯电动汽车应用现状分析及策略探讨

通过对知豆纯电动汽车的调查实践,文章简述了纯电动汽车的优势及其电驱动系统机构,分析了纯电动汽车的应用现状,提出了纯电动汽车应用存在的价格较高、基础设施不完善、电池性能及能量管理有待优化等问题。在此基础上,提出了要继续强化纯电动汽车的基础研究、加快充换电站等基础设施建设和政府政策继续引导支持的建议。     

汽车新节能技术的展望

文章介绍了目前国际上几种比较新颖的节能技术,诸如能量收集与储存新技术、汽主行驶中的能量回收再生技术,电容器和电池二次电池能量回收再生技术、飞轮电动汽车的能量回收与利用技术等等。     

基于专利数据的纯电动汽车发展分析

该文以对全球纯电动汽车专利申请进行检索的结果为依据,分析了全球纯电动汽车专利申请的增长趋势、专利申请的技术构成态势,并从专利申请国、专利申请目标国方面进行了分析,着重分析了我国技术水平与国际上的差距,列举了纯电动汽车核心技术即电池的发明点,为我国新能源技术的研究开发提供专利信息服务。     

增程式电动公交车示范推广

增程式电动车是一种配有地面充电和车载供电功能的纯电驱动的电动汽车,它结合了混合动力车、纯电动车的优点。其动力系统由动力电池系统、动力驱动系统、整车控制系统和辅助动力系统(APU)组成。由整车控制器完成运行控制策略。电池组可由地面充电桩或车载充电器充电,发动机可采用燃油型或燃气型。整车运行模式可根据需要工作于纯电动模式、增程模式、电量保持模式。当工作于增程模式时,节油率随电池组容量增大无限接近纯电动汽车,是纯电动汽车的平稳过渡车型。由于低速扭矩大,高速运行平稳,刹车能量回收效率高,结构简单易维修,在当前混合动力车故障率较高、纯电动车续航里程短的情况下,是一种较为适用于城市公交的新能源客车。     

Survey of R&D in PRT systems

A survey of research and development in advanced transit has been made by Chalmers University of Technology in Gothenburg in cooperation with Trans21 in Boston. Summary findings are reported for fourteen academic research programs and ten development programs for PRT. An earlier version of this paper was presented at the International Conference of PRT and other Emerging Systems held in Minneapolis in 1996.     

Determinants of modal choice in freight transport

In the next few years, exciting developments in the field of freight transport are likely to occur. The Channel Tunnel will be perceived as giving railways much greater distance of operation, compared to the current train ferry to/from Great Britain. The further development of swap-body technology will allow easier modal transfer and the creation, in 1992, of a single market in Europe will transform the pattern of trade. All of these are likely to have significant impacts on modal choice, and hence modal split, in freight transport. Reappraisal by many firms of the modes of transport used is likely but will it result in a net transfer of freight from road to rail and, if so, to what extent? To answer such questions, an accurate and reliable method of predicting modal split is required. Research in the past has concentrated on the development of modal split models based on generalised costs. These fail to explain adequately the prevalence of road freight in the UK. From surveys of freight managers within industry, it is clear that models to date rely too heavily on the economic cost factor and too little on behavioural factors (Jeffs 1985). This paper derives from a recent study of freight transport modal choice from the standpoint of the transport decision-maker within the firm. It attempts to shed light on the actual parameters which should be incorporated into a modal split model. Many variables appear to exert an influence on modal choice decision-making process. However, it is possible to categorise them into six main groups, namely: customer-requirements; product-characteristics; company structure/organisation; government interventions; available transport facilities; and perceptions of the decision-maker him/herself. It is the interactions and inter-relationships between these which ultimately determine freight modal split. This study has shown that the relationship between the outcome of the transport decision process and the values of particular determinants of modal split is not straight-forward, due to the complexity and variety of interactions involved. Perhaps one of the main reasons for researchers' failure hitherto to develop a successful modal-split model has been the preoccupation with techniques that rely on the development of common metric (e.g. generalised cost), which has led to the exclusion of some important explanatory variables along quite different dimensions. Another important issue concerns the appropriate level of aggregation. In order not to reduce the explanatory power of the key variables, it is important to work at a disaggregate level, although this does make substantial demands on data. The use of factor analysis enables both the aggregation of information without loss of behavioural reality and the specification of variables in terms of a common metric. In conclusion, freight transport has usually been examined within too narrow a framework. It must be placed firmly within the context of the total industrial process. The demand for freight transport is directly influenced by the level, composition and geographical distribution of production and consumption activities. Freight flows are complex and so it is highly unlikely that a universal mode-choice model can ever be developed. Future research should, therefore, be directed towards developing partial models in response to specific needs of those involved in decision-taking in the freight sector.     

管道风险分析指数评分法中分值调整初探

管道风险分析指数评分法中重要步骤之一就是确定影响管道事故因素的权重,各个管道风险因素在整个管道事故中所占的权重是不相同的。针对目前管道风险分析指数评分法基本假设之一（各因素的分值范围都是0～100分）,为了更加客观、准确、合理地反映各个风险因素对于管道事故的影响程度,提出并论述了依据层次分析法的数学逻辑性进行综合计算得出管道风险因素的权重,然后对评分法中各个因素的最高分值,根据其权重不同进行相应调整,从而增强评价者对风险因素的认识和评判能力,提高管道风险评价结果的准确性。     

天然气站往复式压缩机活塞失效分析

针对天然气站往复式压缩机活塞的断裂事故,运用失效分析方法,开展了活塞断口扫描电镜分析、能谱和金相分析。根据断口形貌的电镜和金相观察结果,结合理论知识,分析确定了该活塞发生断裂事故的主要原因,即在特定工况下该活塞的材料缺陷是造成断裂的主要因素。     

中国城市道路规划方位性问题研究

文章结合中国的传统建筑文化理念和现代科学原理,从历史文化、能源节约、环境保护、房地产定价、交通安全等多方面分析研究了城市道路在规划和设计时所应遵从的定向规则。     

A century of evolution of the accessibility concept

The concept of accessibility has acquired numerous meanings along multiple dimensions during the century of its evolution. This essay argues for the salience of two dimensions: application-based and definition-based. In its application, accessibility has incorporated positive and normative dimensions which have varied in prominence over time. In its definition, accessibility has varied between a mode of evaluation incorporating measured mobility and proximity, on the one hand, and a predefined market basket of urbanist improvements to transportation and land use systems, on the other. Advocates of the accessibility shift should emphasize both the measured approach to accessibility and accessibility’s normative side.     

生命大过天

文章介绍了广西壮族自治区公路管理局开展专项行动,治理以桥梁为重点的交通基础设施安全隐患的情况,针对在役桥梁、在建桥梁和农村公路桥梁存在的安全隐患提出了相应的治理措施。     

Predicting queue variability to enable analysis of overload risk

ABSTRACT

Predicting the risk of traffic demands and delays exceeding critical limits at road junctions, airports, hospitals, etc., requires knowing how both mean and variance of queue size vary over time. Microscopic simulation can explore variability but is computationally demanding and gives only sample results. A computationally efficient approximation to the mean is used in many modelling tools, but only empirical extensions for variance in particular situations have been available. The paper derives theoretical formulae for time-dependent and equilibrium variance, believed to be novel and to apply generally to queues covered by the Pollaczek–Khinchin mean formula, and offering possible structural insights. These are applied in an extended approximation giving mutually consistent mean and variance estimates with improved accuracy. Tests on oversaturated peak demand cases are compared with Markov probabilistic simulation, demonstrating accuracy (R^2?>?0.99) for typical random, priority-like (M/M/1) and traffic-signal-like (M/D/1) queues. Implications for risk analysis, planning and policy are considered.     

Planning guidelines for metro–bus interchanges by means of a pedestrian microsimulation model

The big paradigm for cities nowadays is to study the movement of pedestrians at the interface between metro and bus systems – metro–bus interchanges. When these interchanges are not well designed, walking is inefficient and can be unsafe for pedestrians. This paper analyses, by means of a pedestrian microsimulation model, metro–bus interchange spaces in order to propose planning guidelines for the city of Santiago de Chile. Specific objectives are (1) to identify the variables that provide efficiency and safety in those spaces; (2) to simulate different scenarios using the pedestrian simulation model LEGION; (3) to propose planning and design guidelines for pedestrian spaces at metro–bus interchanges; and (4) to contrast the recommendations in the recently opened terminal station on Line 1 of Metro de Santiago: Los Dominicos Station.