Carbon and energy footprints of electric delivery trucks: A hybrid multi-regional input-output life cycle assessment

Due to frequent stop-and-go operation and long idling periods when driving in congested urban areas, the electrification of commercial delivery trucks has become an interesting topic nationwide. In this study, environmental impacts of various alternative delivery trucks including battery electric, diesel, diesel-electric hybrid, and compressed natural gas trucks are analyzed. A novel life cycle assessment method, an environmentally-extended multi-region input-output analysis, is utilized to calculate energy and carbon footprints throughout the supply chain of alternative delivery trucks. The uncertainties due to fuel consumption or other key parameter variations in real life, data ranges are taken into consideration using a Monte Carlo simulation. Furthermore, variations in regional electricity mix greenhouse gas emission are also considered to present a region-specific assessment for each vehicle type. According to the analysis results, although the battery electric delivery trucks have zero tailpipe emission, electric trucks are not expected to have lower environmental impacts compared to other alternatives. On average, the electric trucks have slightly more greenhouse emissions and energy consumption than those of other trucks. The regional analysis also indicates that the percentage of cleaner power sources in the electricity mix plays an important role in the life cycle greenhouse gas emission impacts of electric trucks.     

A novel method for identifying inertial parameters of electric vehicles based on the dual H infinity filter

ABSTRACT

Accurate identification of vehicle inertial parameters is essential to the design of vehicle dynamics control systems. In this paper, a novel vehicle inertial parameter identification method based on the dual H infinity filter (DHIF) for electric vehicles (EVs) is proposed. The filter algorithm employs a nonlinear longitudinal vehicle model with three vehicle states. A hierarchical framework is engaged by the DHIF to estimate the vehicle states and inertial parameters concurrently. In order to minimise the disturbance of unknown noise, the vehicle states are estimated by using the linear H infinity filter (LHIF), while the nonlinear H infinity filter (NHIF) utilises the observed states to identify the vehicle inertial parameters. Finally, the proposed estimation method is verified and compared through the dSPACE based hardware-in-the-loop (HIL) simulation experiments. The results indicate that the DHIF-based estimation method is effective to identify the vehicle inertial parameters with high precision, remarkable robustness, and quick convergence.     

A reduced-order nonlinear sliding mode observer for vehicle slip angle and tyre forces

In this paper, a reduced-order sliding mode observer (RO-SMO) is developed for vehicle state estimation. Several improvements are achieved in this paper. First, the reference model accuracy is improved by considering vehicle load transfers and using a precise nonlinear tyre model ‘UniTire’. Second, without the reference model accuracy degraded, the computing burden of the state observer is decreased by a reduced-order approach. Third, nonlinear system damping is integrated into the SMO to speed convergence and reduce chattering. The proposed RO-SMO is evaluated through simulation and experiments based on an in-wheel motor electric vehicle. The results show that the proposed observer accurately predicts the vehicle states.     

平原微丘区低路堤高速公路平面规划设计探讨

低路堤高速公路在平面规划设计方面有很多与常规高速公路方案不同的地方。在初步拟定线形时，应该考虑与原有道路的相互协调，可以在确定线形以后通过合并支线、拆除支线和修改支线的方法使得地方路网配合低路堤高速公路。另外，为了尽可能地减少横向穿越公路的需要，减轻公路的负担，可以通过对公路两旁产业结构的调整，或者对行政区进行重新规划改革，将横穿的需求降到最低。     

水平荷载作用下沥青路面表面开裂机理分析

基于线弹性力学和有限元方法，建立路面结构三维模型。计算垂直荷载、水平荷载及其组合作用下沥青路面力学响应，分析沥青路面表面开裂的机理。结果表明，沥青路面表面裂纹是水平荷载与垂直荷载组合作用导致的剪切或拉伸破坏，水平荷载是破坏的主要因素。     

电动技术在卡车上的应用

本文从能源和环保的角度出发,提出电动汽车将是汽车产业发展的必然趋势,重点介绍了陕汽牌SX4186重型纯电动牵引车在能源、环保上所带来的巨大优势和经济效益。     

北京动车组检修基地与动车检修

分析了动车组检修的意义,介绍了动车组维修的特点,探讨了适合我国国情的动车组修程与修制。重点介绍了新建成的北京动车组维修基地,内容包括基地的特点、主要功能和主要设施。参考动车组高级别检修工艺和流程,北京动车检修基地结合自身生产条件和设备特点,编制了段修用CRH_(2A)型动车组3级修检修工艺和检修流程,完成了两列动车组的3级检修任务,在实际检修中验证了检修工艺和检修流程的可靠性。     

Dynamic anti-plane interaction between an impermeable crack and a circular cavity in an infinite piezoelectric medium

Wave propagation in an infinite elastic piezoelectric medium with a circular cavity and an impermeable crack subjected to steady-state anti-plane shearing was studied based on Green＇s function and the crack-division technique. Theoretical solutions were derived for the whole elastic displacement and electric potential field in the interaction between the circular cavity and the impermeable crack. Expressions were obtained on the dynamic stress concentration factor （DSCF） at the cavity＇s edge, the dynamic stress intensity factor （DSIF） and the dynamic electric displacement intensity factor （DEDIF） at the crack tip. Numerical solutions were performed and plotted with different incident wave numbers, parameters of piezoelectric materials and geometries of the structure. Finally, some of the calculation results were compared with the case of dynamic anti-plane interaction of a permeable crack and a circular cavity in an infinite piezoelectric medium. This paper can provide a valuable reference for the design of piezoelectric actuators and sensors widely used in marine structures.     

电力机车受电弓发展综述

电力机车速度不断提高导致弓网电弧加剧,已经严重制约了高速铁路的发展.本文从受电弓的结构和滑板材料角度阐述国内外电力机车减小弓网电弧危害的现状以及发展,并分析了受电弓滑板的发展趋势.最后从电气角度分析了弓网电弧的产生机理,指出在现有的机械手段的基础上还应结合弓网电弧的电气特性进行研究,从而找到抑制和消除弓网电弧的方法.     

混合动力电动汽车的使用与维护

针对混合动力汽车的结构特点,提出正确使用与维护混合动力电动汽车的内容和方法,以确保其各项性能良好发挥.