Incorporating refuelling behaviour and drivers’ preferences in the design of alternative fuels infrastructure in a city

The purpose of this article is to present an optimization model to plan the deployment strategy for hydrogen refuelling stations in a city when Origin–Destination (OD) data are not available. This model considers two objectives: to maximize the traffic covered by the selected hydrogen refuelling stations and minimize the average distance of the city’s inhabitants to the nearest hydrogen refuelling station. As OD data are assumed to be unavailable, the clustering of stations in the highest traffic zones is prevented by a new constraint that takes into account information on the distribution of existing conventional refuelling stations. This model is applied to Seville, a city in Southern Spain of about 140 km² with a population of around 700,000. This application uses the results of a survey of more than 200 Sevillian drivers on their current refuelling tendencies, their willingness to use alternative fuel vehicles and their minimum requirements (regarding maximum distance to be travelled to refuel and number of stations in the city) when establishing a network of alternative refuelling stations.     

On the distribution of urban road space for multimodal congested networks

Transport systems in real cities are complex with many modes of transport sharing and competing for limited road space. This work intends to understand how space distributions for modes and interactions among modes affect network traffic performance. While the connection between performance of transport systems and general land allocation is the subject of extensive research, space allocation for interacting modes of transport is an open research question. Quantifying the impact of road space distribution on the performance of a congested multimodal transport system with a dynamic aggregated model remains a challenge. In this paper, a multimodal macroscopic fundamental diagram (MFD) is developed to represent the traffic dynamics of a multimodal transport system. Optimization is performed with the objective of minimizing the total passenger hours traveled (PHT) to serve the total demand by redistributing road space among modes. Pricing strategies are also investigated to provide a higher demand shift to more efficient modes. We find by an application to a bi-modal two-region city that (i) the proposed model captures the operational characteristics of each mode, and (ii) optimal dynamic space distribution strategies can be developed. In practice, the approach can serve as a physical dynamic model to inform space distribution strategies for policy makers with different goals of mobility.     

基于多目标粒子群算法的船舶主尺度优化设计研究

粒子群优化是一种新兴的进化计算技术。文章基于多目标粒子群优化算法讨论了船舶主尺度论证中的多目标优化和决策问题。对于多目标优化问题,采用基于Pareto占优方法的多目标粒子群算法得到最优解,然后采用距离理想解最近的方法对这些Pareto最优解给出排序。应用文中给出的两个阶段求解方法,对散装货船概念设计阶段主尺度确定的问题进行了分析。结果表明,综合多目标粒子群优化和决策技术,能够迅速、客观地选择合理的船舶主尺度,可以给设计人员提供更多的选择。这种综合方法也能够广泛用于船舶其他设计领域。     

考虑路面不平度神经网络的悬架参数优化

以1/4车辆模型为例,构建了考虑路面不平度的3×3神经网络系统,并进行了多种路面条件下汽车悬架参数优化。计算结果表明,将路面不平度作为神经网络输入之一的神经网络优化系统与已有神经网络系统相比,可使设计人员综合考虑路面的影响,从而得到适应条件更广泛的悬架参数。     

双前桥转向机构优化设计方法研究

双前桥转向机构包含两个独立的转向梯形机构和双前桥间的转向联动机构—双摇臂系统。文中分析了双前桥转向机构应实现的功能、运动规律和与其它系统可能造成的运动干涉,提出了同时保证双前桥汽车车轮转向时做纯滚动和杆系干涉造成的车轮异常磨损最小的多目标优化设计方法。     

解决正面碰撞布置问题的优化方案

文章针对某左舵车型在正面碰撞开发过程中出现车体加速度较大和局部车身侵入量过大问题进行分析,运用仿真手段进行原因分析,针对车身结构和机舱布置存在的缺陷,提出有效的改进方案.优化后车体加速度和车身侵入量等均得到改善,车体加速度由原来的51.2g降低到39.5g,车身侵入量由78mm减小到40mm.结果表明优化变速器与副车架...     

摩托车车架模态优化分析

利用试验和有限元相结合的方法,对相同型号不同企业生产的两款车架进行了模态对比分析发现,车架的焊接工艺对模态特性有重要的影响,而在实际生产过程中,生产企业往往仅从力学强度出发来控制焊接工艺,忽视了焊接工艺对模态特性的影响,从而严重恶化了车架的动态特性。     

侧架磨耗板安装孔加工专机主轴的设计

文章对机车侧架磨耗板安装孔加工专用机床的结构进行了分析和阐述,并重点介绍了专机主轴的设计及优化过程。     

四驱混联电动汽车的燃油经济性优化

从等效燃油量出发,建立了四驱混联电动汽车在充/放电模式下的等效模型。控制发动机工作在最经济区域,以等效燃油消耗率为优化目标函数,寻求出整车燃油消耗量最低的理想操作线。通过仿真和台架试验得到燃油经济性优化结果,结果表明理想操作线决定了发动机和各个电机的最佳控制值,可使车辆系统的效率最高,油耗最低。     

汽车空调温度传感器位置及控制参数优化研究

以某款微型汽车为对象,对空调蒸发器表面结霜对制冷量的影响进行了分析,对温度传感器位置和控制参数(切断/接通温度)进行了优化。汽车环境模拟试验结果表明,优化后空调各出风口平均温度降低了1.7~2.7℃,压缩机的切断次数降低了79%,提高了车内环境的舒适性和空调系统的可靠性。