交叉口高峰时段右转车辆通行时间可靠性研究

早高峰时段对右转车辆通过十字交叉口的时间进行连续2h的观测,对获得的样本数据采用统计学的方法进行分析,得出样本基本符合正态分布的一般假设,运用检验对这一假设进行检验,得到其符合正态分布的一般规律。基于上述分布规律,通过提出的交叉口的右转通行时间修正系数,对路段行程时间可靠性模型进行改进,得到适用于十字交叉口处右转车的通行时间可靠性评价模型。     

新能源汽车发展的技术经济分析

随着新能源汽车的不断发展,呈现出多种多样的技术途径。文章从技术经济的角度分析新能源汽车技术的发展趋势,同时对中国汽车产业发展提出了3点建议,对发展新能源汽车提出政策建议。表明,未来新能源汽车将沿着混合动力／插电式复合电动车、纯电动车的路径发展,指出国家应重点投资关键技术,进一步完善国内标准法规和环保补贴标准,规范原材料市场管理,提高中国的整体竞争力。     

CVT夹紧力控制系统动态性能及其影响因素分析

在对某型无级变速器夹紧力控制系统结构原理进行分析的基础上,采用键合图理论建立其数学模型,对该系统动态性能进行仿真。分析结构参数对系统阶跃响应时压力上升时间和超调量的影响,找出了对系统动态性能影响较大的结构参数,为系统动态性能的优化奠定基础。台架试验结果表明,所建立的夹紧力控制系统模型具有较高精度,仿真结果可信。     

纯电动汽车电子差速系统研究综述

文章综述了纯电动汽车的驱动结构以及轮毂电机驱动电动汽车的优点,然后阐述了纯电动汽车电子差速系统的结构与工作原理,并详细介绍了电子差速系统的控制方法和控制理论,同时对三种控制方法进行了对比分析,指出其优缺点和适应场合。最后对纯电动汽车电子差速的发展进行了展望。     

汽车线控制动系统的可靠性分析和容错技术研究

采用失效模式与后果分析和故障树分析相结合的方法对汽车线控制动(brake-by-wire,BBW)系统的可靠性进行了分析,提出了基于可靠性分析和容错技术相结合的系统冗余结构设计方法,并设计了BBW系统的双冗余结构.研究结果表明:该结构可满足系统可靠性要求.最后阐述了提高BBW系统可靠性的关键技术.     

A corridor-centric approach to planning electric vehicle charging infrastructure

The transition to electric vehicles (EV) faces two major barriers. On one hand, EV batteries are still expensive and limited by range, owing to the lack of technology breakthrough. On the other hand, the underdeveloped supporting infrastructure, particularly the lack of fast refueling facilities, makes EVs unsuitable for medium and long distance travel. The primary purpose of this study is to better understand these hurdles and to develop strategies to overcome them. To this end, a conceptual optimization model is proposed to analyze travel by EVs along a long corridor. The objective of the model is to select the battery size and charging capacity (in terms of both the charging power at each station and the number of stations needed along the corridor) to meet a given level of service in such a way that the total social cost is minimized. Two extensions of the base model are also considered. The first relaxes the assumption that the charging power at the stations is a continuous variable. The second variant considers battery swapping as an alternative to charging. Our analysis suggests that (1) the current paradigm of charging facility development that focuses on level 2 charging delivers poor level of service for long distance travel; (2) the level 3 charging method is necessary not only to achieve a reasonable level of service, but also to minimize the social cost; (3) investing on battery technology to reduce battery cost is likely to have larger impacts on reducing the charging cost; and (4) battery swapping promises high level of service, but it may not be socially optimal for a modest level of service, especially when the costs of constructing swapping and charging stations are close.     

Deploying public charging stations for electric vehicles on urban road networks

This paper explores how to optimally locate public charging stations for electric vehicles on a road network, considering drivers’ spontaneous adjustments and interactions of travel and recharging decisions. The proposed approach captures the interdependency of different trips conducted by the same driver by examining the complete tour of the driver. Given the limited driving range and recharging needs of battery electric vehicles, drivers of electric vehicles are assumed to simultaneously determine tour paths and recharging plans to minimize their travel and recharging time while guaranteeing not running out of charge before completing their tours. Moreover, different initial states of charge of batteries and risk-taking attitudes of drivers toward the uncertainty of energy consumption are considered. The resulting multi-class network equilibrium flow pattern is described by a mathematical program, which is solved by an iterative procedure. Based on the proposed equilibrium framework, the charging station location problem is then formulated as a bi-level mathematical program and solved by a genetic-algorithm-based procedure. Numerical examples are presented to demonstrate the models and provide insights on public charging infrastructure deployment and behaviors of electric vehicles.     

Forward power-train energy management modeling for assessing benefits of integrating predictive traffic data into plug-in-hybrid electric vehicles

In this paper, a forward power-train plug-in hybrid electric vehicle model with an energy management system and a cycle optimization algorithm is evaluated for energy efficiency. Using wirelessly communicated predictive traffic data for vehicles in a roadway network, as envisioned in intelligent transportation systems, traffic prediction cycles are optimized using a cycle optimization strategy. This resulted in a 56-86% fuel efficiency improvements for conventional vehicles. When combined with the plug-in hybrid electric vehicle power management system, about 115% energy efficiency improvements were achieved. Further improvements in the overall energy efficiency of the network were achieved with increased penetration rates of the intelligent transportation assisted enabled plug-in hybrid electric vehicles.     

Exploring low carbon transition pathways for the UK road transport sector

This paper uses an analytical framework of multi-level and multi-phase perspectives to explore low carbon transition pathways for the UK road transport system. The work draws on the impact made by the national (UK) and regional (EU) low carbon policy instruments on the UK road sector. The results show that the transformation pathway, which is at the take-off phase on a large scale, is the only fully active pathway. The transformation is mainly characterized by the adoption of biofuel blends and hybrid electric vehicles, as well as niche technologies. For the emergence of an ideal low carbon road system in the UK, it is shown that the transformation pathway is insufficient and the likely pathway sequence to full decarbonization will be transformation-substitution-de-alignment/re-alignment. However, the dynamics that can favour a smooth process of this sequence will demand a range of active niche technologies and strong government intervention.     

中国轻型汽车国Ⅳ国Ⅴ排放法规对比分析

2013年9月为了保护环境,保障人体健康,防治大气污染,由中华人民共和国环境保护部与国家质量监督检验检疫总局联合发布《轻型汽车污染物排放限值及测量方法（中国第五阶段）》为国家污染物排放标准。本文对国Ⅳ标准与国Ⅴ标准的限值,与技术路线进行对比分析。