37500方LEG运输船螺旋桨毂帽鳍设计研究

毂帽鳍是一种通过回收螺旋桨毂涡旋转能量来达到节能效果的船舶桨后节能装置。本文针对我公司承建的37500方LEG运输船,运用CFD软件对粘性流场中毂帽鳍的敞水性能进行了计算研究,着重考察了毂帽鳍的根部螺距角、错位角、直径比及纵向位置等因素对效率的影响,通过多方案优选设计了适用于该船的毂帽鳍方案,并对该方案进行了模型试验验证。结果表明：在螺旋桨工作点时,螺旋桨效率提高了1.26%。考虑到模型试验的尺度效应,在实船应用时其节能效果将更加显著。     

平行流冷凝器在大型货车空调中的应用

空调系统是现代货车的重要组成部分,空调系统性能的优劣关系到驾驶安全。平行流冷凝器作为新一代高效冷凝器,具有体积小、结构紧凑、换热效率高等诸多优点,可提高货车空调性能。本文就平行流冷凝器在大型货车上的应用进行了分析,总结出：在货车上应用平行流冷凝器不仅投资可减少,还可以降低油耗和变暖总当量（TEWI）,节能和环保效果较好...     

城市交通政策对能耗和温室气体排放的影响

简要介绍了12个大城市限制小汽车使用的交通政策,评估其在减少能源消耗和温室气体排放方面取得的效果.这些城市都经历了能源消耗、温室气体排放和私人小汽车保有量增长的过程.在欧洲,多个地区通过提高公共交通的服务质量,增加了公交客运量,但新增乘客来自于非机动交通而非私人小汽车,这实际上增加了能源消耗总量.各城市旨在减少私人小汽...     

宜万铁路齐岳山隧道629高压充水溶腔处理技术

在齐岳山隧道正洞DK363+629掌子面进行超前水平钻探时,揭示出前方存在一个大型腔体,随后实施超前探测,初步判断了腔体形状,对腔体进行了处理。首先对溶腔进行注浆试验,总计注浆1 613 m3,注浆效果不明显,掌子面停止注浆试验;注浆试验失败后,对DK363+629溶腔进行放水试验,放水量为3 000 m3/h,持续放水共计144 h,水量约43万m3,水压持续在0.2 MPa左右,由于受到外界降雨的影响水压持续上扬,证明腔体具有良好的地表联通性和水量补给持续性,为了保证施工安全停止了放水试验。平导贯通后可采用自然流出法排水,并对腔体采取"释能降压"施工。本次泄水总量约63万m3,水压自0.4 MPa降至0.0 MPa,水量稳定在约1 000 m3/h;随后对腔体实施爆破施工,爆破后采用管道引排的方法在不改变原有水流方向和不影响整体地下水系的情况下顺利通过。     

威志V5全新上市以进取超越期待

市场对于轿车的消费需求逐渐向理想消费阶段发展,这就对汽车的设计和制造技术提出了新的要求,天津一汽推出了威志v5这款新车来积极应对当前经济型轿车竞争激烈的形势。威志V5导入了新的“智能双I”的设计理念;在造型和内饰的细节上做了很多人性化的设计和调整;配备了很多先进技术使轿车更加节能和安全;使用自主研发的新的CA4GA5发动机更节能和环保。完全由天津一汽独立研发设计的威志v5在安全、节能、环保和新技术应用方面都为经济型轿车树立了新标杆。     

The impact of scale on energy intensity in freight transportation

This paper analyzes energy intensities of ships, diesel–fuelled railways, trucks, and aircraft, using publicly available data. The analysis suggests that differences in operation, not technology, explain most of the variation in energy intensity within and across modes. Among the operational characteristics, most important is the amount of cargo weight transported per vehicle and therefore the scale of the respective transportation system. It is found that each mode has a characteristic envelope in an average energy intensity versus average cargo weight diagram, and estimates of the elasticities of energy intensity with respect to load size are made.     

电动汽车能耗预测的研究

随着电动汽车的数量日趋增多,人们对于电动汽车能耗的关注度也逐渐增加。电动汽车受到电池性能和容量的约束,同时受到充电桩的位置、数量和充电时间的限制,容易使得驾驶员产生"里程焦虑"。因此续驶里程成为驾驶员关注的重要指标之一。准确的能耗预测能够给予驾驶员出行指导,减缓"里程焦虑"。围绕电动汽车能量消耗的影响因素进行了归纳总结,介绍了近年来能耗预测技术的研究现状和不足,并提出未来研究方向的发展趋势。     

Nonlinear programming methods based on closed-form expressions for optimal train control

This paper proposes a novel approach to solve the complex optimal train control problems that so far cannot be perfectly tackled by the existing methods, including the optimal control of a fleet of interacting trains, and the optimal train control involving scheduling. By dividing the track into subsections with constant speed limit and constant gradient, and assuming the train’s running resistance to be a quadratic function of speed, two different methods are proposed to solve the problems of interest. The first method assumes an operation sequence of maximum traction – speedholding – coasting – maximum braking on each subsection of the track. To maintain the mathematical tractability, the maximum tractive and maximum braking functions are restricted to be decreasing and piecewise-quadratic, based on which the terminal speed, travel distance and energy consumption of each operation can be calculated in a closed-form, given the initial speed and time duration of that operation. With these closed-form expressions, the optimal train control problem is formulated and solved as a nonlinear programming problem. To allow more flexible forms of maximum tractive and maximum braking forces, the second method applies a constant force on each subsection. Performance of these two methods is compared through a case study of the classic single-train control on a single journey. The proposed methods are further utilised to formulate more complex optimal train control problems, including scheduling a subway line while taking train control into account, and simultaneously optimising the control of a leader-follower train pair under fixed- and moving-block signalling systems.     

Practical vehicle rollover avoidance control using energy method

In this paper, a novel rollover prevention control algorithm is developed for application on vehicles with a high centre of gravity. The developed algorithm can be implemented on any vehicle equipped with an electronic stability program with or without an extra roll rate sensor. The vehicle rollover index is defined from the vehicle lateral kinetic energy and the new concept of virtual gravity. The algorithm is implemented on a production hydraulic control unit and tested using a typical medium size sport utility vehicle up to a speed of 110 km h^-1. The test results show that the control algorithm prevents the vehicle rollover very successfully without any noticeable false activation or over correction resulting in severe under steer. Also, the controlled wheel speed shows a very stable and smooth trace.     

打桩机落锤过程阻力及能量损失

根据油缸提升、自由落锤式打桩机工作装置的结构，分析和桩锤下落过程中，油缸下腔泄油阻力、上腔负压阻力及有关部位机械磨擦阻力的产生原因和对桩锤能量的影响作用，指出了这种打桩机减小落锤能量损失是提高作业效率的途径