Energy management and design optimization for a series-parallel PHEV city bus

Series-parallel PHEV city buses combine the advantages of series and parallel configurations and have been used in China. However, the design and energy management of series-parallel PHEV city buses based on Chinese driving conditions still need to be investigated. In this paper, an equivalent consumption minimization strategy is provided to optimize energy management for series-parallel PHEV city buses, and the process of the equivalent consumption minimization strategy for series-parallel is presented in this paper. Compared with the validated rule-based energy control strategy, ECMS shows a fuel economy improvement of 8.2 % in the CBCD (Chinese Bus Driving Cycle). Based on the optimal energy management, a design for a generator motor in the series-parallel configuration has been processed. The fuel consumption has been shown to decrease, with an increase in generator power, because the system with the higher generator power can work at a higher efficiency in the series mode and operate the engine in the high efficiency area in the parallel mode. Besides, in terms of costof- ownership for a PHEV bus for lifetime of 8 years, although the high generator power will lead to high purchase cost for series-parallel PHEV bus, a series-parallel PHEV city bus with a generator of 100 kW maximum power will still show small advantage in cost-of-ownership, based on current motor price and natural gas price.     

数显轮径尺使用中的问题及建议

针对车辆维修作业人员提出的数显轮径尺使用中存在的问题，进行现场分析，提出解决问题的办法和建议，保证计量器具的检测准确度。     

经过演变的广州城市轨道交通网络规划

介绍广州市城市轨道交通线网规划的发展及线网架构和功能等级的划分，综述了线网规模规划、系统规划、系统选型及资源合理配置。     

往复流散热方式的锂离子电池热管理

为解决电池模块内部单体电池间的温度不均匀性而影响电池的使用性能和寿命的问题,本文中采用了一种往复流冷却方式,使冷却空气流动方向周期性逆转,以降低单向流空气冷却方式时单体电池沿空气流方向的温度梯度。结果表明,采用往复流冷却方式后,在1C和13.33C放电倍率下,电池温度均匀性分别提高了12.1%和62.4%,电池模块的使用性能和安全性得到改善,电池使用寿命得以提高。同时,文中还利用计算流体动力学虚拟试验与正交优化相结合,对影响往复流散热性能的往复流入口的速度与温度和往复周期3个参数进行了优化,并揭示了它们对电池最高温度和温差的影响规律。     

Flexural experimental study on continuous reinforced concrete beams strengthened with basalt fiber reinforced polymer/plastic

This paper discusses a new fibrous composite known as continuous basalt fiber reinforced polymer/plastic (BFRP). Compared with other fiber reinforced polymer/plastic, BFRP has many advantages, such as ductility, high thermal resistance, corrosion resistance and economic cost. To test mechanical properties and failure modes of flexural members strengthened with BFRP, flexural experiment is conducted on four two-span T-section continuous beams strengthened with BFRP and one un-strengthened comparative beam. The experimental result shows that the strengthened beams perform remarkably in terms of yield strength, ultimate strength and ductility. BFRP has good prospects in retrofitting and strengthening of concrete structures which require good ductility and corrosion resistance.     

城市轨道交通客流规模影响因素分析

客流规模是决定轨道是否建设的决定性因素.以广州市的轨道交通发展为例,借鉴国外一些城市的先进经验,从沿线土地利用、城市经济水平、城市中心区潜在的增长前景、自行车-公共汽车的联运、有效的城市管理、高效的经营等6个方面对影响客流规模的因素进行了阐述.一般的客流预测量往往偏高.而实际影响客流规模的因素大都较难把握.     

基于DDS中间件的性能测试

DDS中间件是一种轻便的、能够提供实时信息传送的中间件技术,该文以OpenSplice DDS中间件为例,研究了其通信过程,介绍了其为实现实时数据分发服务提供的图形化建模工具DDS Power Tools,并设计应用对其实时和吞吐性能进行了第三方测试。     

Characterization of traffic oscillation propagation under nonlinear car-following laws

Unlike linear car-following models, nonlinear models generally can generate more realistic traffic oscillation phenomenon, but nonlinearity makes analytical quantification of oscillation characteristics (e.g, periodicity and amplitude) significantly more difficult. This paper proposes a novel mathematical framework that accurately quantifies oscillation characteristics for a general class of nonlinear car-following laws. This framework builds on the describing function technique from nonlinear control theory and is comprised of three modules: expression of car-following models in terms of oscillation components, analyses of local and asymptotic stabilities, and quantification of oscillation propagation characteristics. Numerical experiments with a range of well-known nonlinear car-following laws show that the proposed approach is capable of accurately predicting oscillation characteristics under realistic physical constraints and complex driving behaviors. This framework not only helps further understand the root causes of the traffic oscillation phenomenon but also paves a solid foundation for the design and calibration of realistic nonlinear car-following models that can reproduce empirical oscillation characteristics.     

A Preliminary Analysis on the Necessity of Battery Pack Cooling for Pure Electric Vehicles

针对最近市场上出现的一些电池组不配备散热装置的纯电动车,对一款正在使用的、不带散热装置的纯电动车用磷酸铁锂电池组,通过试验测试和模型仿真进行不加散热的可行性分析.结果表明,刚使用的纯电动车电池组内阻小,热容量大,温升有限,在保证电池初始温度合适的情况下(尤其当采用换电模式),电池组可以不加散热装置,但是随着电池的老化,电池内阻大幅增加,导致温升增大,此时电池组应考虑散热.     

柴油机活塞连杆组件缸体内现场定位工具的研制和应用

<正>1引言从1892年德国工程师鲁道尔夫·狄赛尔设计的柴油机到现在已有112年历史。随着柴油机制造工业的迅速发展,具有良好的经济性、结构紧凑、功率范围大等特点的机型不断出现,在国民经济发展中,特别是交通运输行业这个国民经济建设中的命脉作用越发凸显其重要性。