Prediction procedure for wear distribution of transient rolling tire

As a research method, finite element analysis (FEA) with ABAQUS can help researchers to study throughout the whole process of abnormal tire wear. For precise tread wear simulation, this paper introduces a tire finite element model building method. Then, the model is verified by comparing its simulation results with experiment data. Based on the verified model, tire high-speed rolling procedure is presented by combining steady-state transport analysis and dynamic analysis. To predict the wear distribution, micro tread wear calculation method is described. Finally, the wear prediction procedure of tread mesh evolving is introduced and tire polygonal wear pattern is simulated by this procedure.     

Combined power management/design optimization for a fuel cell/battery plug-in hybrid electric vehicle using multi-objective particle swarm optimization

In this paper, the combined power management/design optimization problem is investigated for a fuel cell/Liion battery PHEV. Formulated as a constrained multi-objective optimization problem (MOP), the combined optimization problem simultaneously minimizes the vehicle cost and fuel consumption subject to the vehicle performance requirements. With an emphasis on developing a generic optimization algorithm to find the Pareto front for the synthesized MOP, the Pareto based multi-objective particle swarm optimization (PMOPSO) algorithm is developed, which solely depends on the concept of Pareto dominance. Three approaches are introduced to the PMOPSO method to address the constrained MOP. They are: (i) by incorporating system constraints in the original objective functions, the constrained MOP is transformed to an unconstrained MOP; (ii) to avoid being trapped in local minima, a disturbance operator with a decaying mutation possibility is introduced; (iii) to generate a sparsely distributed Pareto front, the concept of crowding distance is utilized to determine the global guidance for the particles. Finally, under the Matlab/Simulink software environment, simulation results are presented to demonstrate the effectiveness of the PMOPSO in the derivation of the true Pareto front.     

Energy and wear optimisation of train longitudinal dynamics and of traction and braking systems

Traction and braking systems deeply affect longitudinal train dynamics, especially when an extensive blending phase among different pneumatic, electric and magnetic devices is required. The energy and wear optimisation of longitudinal vehicle dynamics has a crucial economic impact and involves several engineering problems such as wear of braking friction components, energy efficiency, thermal load on components, level of safety under degraded or adhesion conditions (often constrained by the current regulation in force on signalling or other safety-related subsystem). In fact, the application of energy storage systems can lead to an efficiency improvement of at least 10% while, as regards the wear reduction, the improvement due to distributed traction systems and to optimised traction devices can be quantified in about 50%. In this work, an innovative integrated procedure is proposed by the authors to optimise longitudinal train dynamics and traction and braking manoeuvres in terms of both energy and wear. The new approach has been applied to existing test cases and validated with experimental data provided by Breda and, for some components and their homologation process, the results of experimental activities derive from cooperation performed with relevant industrial partners such as Trenitalia and Italcertifer. In particular, simulation results are referred to the simulation tests performed on a high-speed train (Ansaldo Breda Emu V250) and on a tram (Ansaldo Breda Sirio Tram). The proposed approach is based on a modular simulation platform in which the sub-models corresponding to different subsystems can be easily customised, depending on the considered application, on the availability of technical data and on the homologation process of different components.     

金属的咆哮 机械的诗歌

2009年底,三大艺术机构向公众展出了粗加工金属制成的艺术品,原型皆来自汽车。这是一场远距离的,围绕材料以及汽车地位的对话。第一件,也许是最具冲击力的一件作品,来自于Jeremy Deller的装置艺术作品,该作品获得了2004年泰纳奖(Turner Prize)。作为一个天生具备挑衅精神的英国艺术家,Deller于10月11月在芝加哥MCA展示了他的作品《它就是它,关于伊拉克的谈话(It iswhat it is:Conversation about Iraq)》。     

Numerical modeling of hollow-cone fuel atomization,vaporization and wall impingement processes under high ambient temperatures

In the following paper, a numerical study of the atomization, vaporization and wall impingement processes of hollow-cone fuel spray from high-pressure swirl injectors under various ambient temperature conditions was carried out. Also, the availability of applied models and the effect of ambient temperature on spray characteristics is discussed. The Linearized Instability Sheet Atomization (LISA) model combined with the Aerodynamically Progressed Taylor Analogy Breakup (APTAB) model, the improved Abramzon model and the Gosman model are used to calculate the atomization, vaporization and wall impingement processes of hollow-cone fuel spray, respectively. Spray models are implemented with the modified KIVA code. The calculation results of the spray characteristics under two ambient temperatures, including spray tip penetration, spray structure and radial distance after spray-wall impingement are compared to the experimental results obtained by the Laser Induced Exciplex Fluorescence (LIEF) technique. The droplet size distribution, ambient gas velocity field, vapor phase distribution and fuel film mass generated by spray-wall impingement, measurements which are generally difficult to obtain by experimental methods, are also calculated and discussed. Quantitative discussions on the effect of the ambient temperature on the spray development process are conducted. It is shown that the applied models are applicable even in the high ambient temperature condition.     

Development of fuel cell hybrid powertrain research platform based on dynamic testbed

An experimental research platform based on a dynamic testbed is developed and applied for fuel cell hybrid powertrain integration and control. A driver brake model is added to the dynamic testbed to simulate the braking process of an electric vehicle. Sub-systems of the fuel cell hybrid powertrain are tested, and characteristic parameters are obtained. A simulation platform is constructed in LabVIEW environment, and its validity is verified by dynamic test results. A real time control system is developed with an embedded PC for the function of rapid control prototyping. Using this platform, fuel cell battery hybrid and fuel cell supercapacitor hybrid configurations are investigated. This platform provides a powerful tool for fuel cell powertrain research and development.     

产能扩张带来质量隐患

从2009年中国取代美国成为世界上最大的汽车市场以来,汽车制造商已然进入了一场激烈的扩张竞赛。在过去两年里,数万亿元人民币涌入汽车制造行业。汽车制造商开始疯狂地扩大产能。按照这种扩张速度,中国的汽车年产能到201 3年将增至31 00万辆,达到2009年产能的两倍。而在中国开展业务的国际汽车制造商则显得保守一些。过去四年里,在占据全国乘用车一半产量的情况下,     

Automotive windshield — pedestrian head impact: Energy absorption capability of interlayer material

During accident, the interlayer of windshield plays an important role in the crash safety of automotive and protection of pedestrian or passenger. The understanding of its energy absorption capability is of fundamental importance. Conventional interlayer material of automotive windshield is made by Polyvinyl butyral (PVB). Recently, a new candidate of high-performance nanoporous energy absorption system (NEAS) has been suggested as a candidate for crashworthiness. For the model problem of pedestrian head impact with windshield, we compare the energy absorption capabilities of PVB and NEAS interlayers, in terms of the contact force, acceleration, velocity, head injury criteria, and energy absorption ratio, among which results obtained from PVB interlayers are validated by literature references. The impact speed is obtained from virtual test field in PC-CRASH, and the impact simulations are carried out using explicit finite element simulations. Both the accident speed and interlayer thickness are varied to explore their effects. The explicit relationships established among the energy absorption capabilities, impact speed, and interlayer material/thickness, are useful for safety evaluation as well as automotive design. It is shown that the NEAS interlayer may absorb more energy than PVB interlayer and it may be a competitive candidate for windshield interlayer.     

Steering torque control using variable impedance models for a steer-by-wire system

This paper presents a novel sensor-less steering torque control method for applications to the steer-by-wire system. A steer-by-wire system has not any mechanical link to connect a steering wheel and a rack and pinion gear module. Instead of mechanical devices, two electric motors are used on each side. A one motor is attached to the steering wheel and the other is set on rack and pinion. The motor on the steering wheel works as a deliverer between a steering torque and load torque from the road. In this paper, we focus on motion control related to the steering feel based on impedance control. Therefore, the model of rack and pinion is not considered in this work. In most power steering systems, a torque sensor is used to set impedance effect on driver’s steering feel. In this paper, we proposed a novel steering control method without using any torque sensors. The effectiveness of a proposed method is confirmed from experimental results.