电动汽车制动能量回收性能检测研究进展

传统汽车工业的发展带来环境污染、气候变暖、能源危机等问题,电动汽车在各国政府的大力扶持下迅速发展。作为提高电动汽车续航里程与能源效率的有效方法,制动能量回收技术已成为一项通用性关键技术,但目前制动能量回收技术的研究集中在控制策略研究上,少有针性能评价的研究。论文首先对国内外制动能量回收性能评价指标的研究现状进行了分析;其次,从试验方法、典型行驶工况和车速跟踪三方面对制动能量回收性能测试方法进行了研究;最后,论述了电动汽车制动能量回收性检测存在的问题和未来的发展趋势。     

某车型前下控制臂前衬套异响问题研究与优化

某车型在下车体涉水后,以低速 10 km/h～25 km/h 连续经过减速带,随着前轮上抬,车辆前悬挂受力拉升时,车内能明显感知到前部位置出现类似橡胶挤压的“嘎吱嘎吱”异响,车速越高声音越明显,声音出现后,在颠簸路面上连续行驶约 1 km,该声音会慢慢变小直至消失。但是当车辆在未涉水情况下以同样工况经过路面时,声音没有出现。通过临时改制对故障件衬套前套管与橡胶接触位置增加铁丝,加大其干涉量,确认该异响为摆臂前衬套翻边的橡胶涉水后,与衬套内套管摩擦关系发生变化,产生异常的挤压滑移导致的。对前悬挂系统结构分析、排查并整改验证,确认摆臂前衬套内套管及其与翻边橡胶的干涉量是导致该异响的关键因素。将摆臂衬套的结构由原来带橡胶翻边结构更改至法兰平面架构,主观上对其进行批量评估,均未发现异响。     

船舶中央冷却水系统变频水泵流量特性

针对船舶中央冷却水系统变频水泵切换效率低、能耗大及流量波动变化等问题,深入研究2350TEU集装箱船在各种负荷变化和海水环境温度变化时的变频泵调速流量特性,分析变频水泵在单泵、双泵2种状态切换时的流量特性、效率特性和功率特性,计算水泵变频切换时的最佳转速与流量。结果表明:实现单双泵无扰动切换,可减少切换时流量产生波动对止回阀的冲击,提高变频泵的工作效率,降低系统能耗,为船舶中央冷却水节能控制系统设计提供理论支持。     

ISO与ITTC方法在实船航速修正应用对比

介绍了ISO15016：2015和ITTC2017两种实船航速修正方法,对比了两种修正方法的测速要求和修正流程。并通过8种具有代表性的船舶试航数据,采用两种方法对试航数据进行修正,分析了不同环境因素的修正结果,可为今后船舶EEDI测速试验和航速修正提供参考。     

某28000DWT散货船EEDI分析研究

文章针对某28 000DWT散货船的船型尺度、主要性能、基本布置以及内部结构等内容提出了散货船EEDI这一概念,并提出了一系列的改进措施以提高散货船EEDI。     

基于分类管理的汽车制造业供应商评价与选择方法

针对汽车制造业零部件数量大、种类多及差别大的特点,结合零部件在整车中的地位和作用,提出将零部件按重要程度分类的思想,并给出具体的分类指标,在此基础上建立汽车制造业供应商评价与选择程序模型。重点阐述了一级零部件的评选策略,并对现有的各种评价方法的优缺点进行了比较,为汽车制造业对零部件供应商的评价与选择提供了依据。     

行驶质量评价指标的回顾和展望

道路作为满足公众行驶需要的一种特殊产品,其好坏的根本量度之一就是行驶质量评价指标。由于这个指标取决于道路的破损情况,因此将其与道路表面的粗糙度特征建立回归关系才方便应用。自从20世纪60年代以来,确定行驶质量指标的主要参数就不断演变。先是人工实测车辙,破损及修补面积,再是各种仪器实测的路面平整度,比如国际平整度指数,IRI。本文在大量的研究基础上,指出了现行主要参数的不足,并提出了一个确定行驶质量指标的新参数,既乘客所直接感受到的竖直方向上的加速度的变化率,JERK。     

采用小波分析进行电喷汽油机失火诊断的研究

采取小波变换的方法对电喷汽油机的瞬时转速波动信号进行分解去噪处理。采用小波变换的Mallat快速算法,并从分解后的信号中提取特征值,用于诊断汽油机的失火故障。通过台架验证试验表明:文中采取的方法可以有效去除高速时的干扰信号,能满足失火诊断的要求。     

Lane changing patterns of bane and benefit: Observations of an uphill expressway

A mechanism is unveiled by which congestion forms on a 3-lane, uphill expressway segment, and causes reductions in output flow. Vehicular lane-changing (LC) is key to the mechanism, particularly LC induced by speed disturbances (SDs) that periodically arise in the expressway’s median and center lanes. Early in the rush, when flow was relatively low in the shoulder lane, drivers readily migrated toward that lane to escape the oncoming SDs. The shoulder lane thus acted as a ‘release valve’ for the high vehicular accumulations created by the SDs, such that forced vehicular decelerations were short-lived. The release valve failed only later in the rush, when flow increased in the shoulder lane in response to rising demand. LC induced by the SDs thereafter became disruptive: the decelerations they imposed spread laterally, and a persistent queue formed in all lanes. Long-run output flow dropped each day by 4-11% once the queue engulfed the base of the incline, and impeded vehicle ascent.Subtle details of this mechanism became visible by examining thousands of vehicle trajectories that were extracted from a series of eleven roadside video cameras. Though these trajectories were collected from only a single day, we suspect that the findings can be generalized to other days at the present site, and to other sites. This is because: (i) conspicuous features of the mechanism were repeatedly observed in loop detector data that were measured over many days at the site; (ii) these macroscopic features are consistent with observations previously made at other sites; and (iii) the more subtle details unveiled by the trajectories are compatible with a general theory of multi-lane traffic.     

Dynamic optimization of ship energy efficiency considering time-varying environmental factors

Nowadays, optimization of ship energy efficiency attracts increasing attention in order to meet the requirement for energy conservation and emission reduction. Ship operation energy efficiency is significantly influenced by environmental factors such as wind speed and direction, water speed and depth. Owing to inherent time-variety and uncertainty associated with these various factors, it is very difficult to determine optimal sailing speeds accurately for different legs of the whole route using traditional static optimization methods, especially when the weather conditions change frequently over the length of a ship route. Therefore, in this paper, a novel dynamic optimization method adopting the model predictive control (MPC) strategy is proposed to optimize ship energy efficiency accounting for these time-varying environmental factors. Firstly, the dynamic optimization model of ship energy efficiency considering time-varying environmental factors and the nonlinear system model of ship energy efficiency are established. On this basis, the control algorithm and controller for the dynamic optimization of ship energy efficiency (DOSEE) are designed. Finally, a case study is carried out to demonstrate the validity of this optimization method. The results indicate that the optimal sailing speeds at different time steps could be determined through the dynamic optimization method. This method can improve ship energy efficiency and reduce CO₂ emissions effectively.