城市快速路基本路段车辆运行特性调查与分析

快速路系统既承担大城市内部中长距离的机动车交通,又承担大城市与区域内其它城镇联系的对外交通。依托教育部高等学校博士学科点专项科研基金项目《城市快速路系统通行能力计算与服务水平评价方法研究》,对国内七个典型城市的快速路进行了交通调查,从交通量的变化特性、车速运行特性及交通组成特性方面对车辆运行特性进行了分析。     

路桥过渡段纵向处理长度范围研究

桥头跳车现象是公路中常见的病害之一,它的存在严重影响了行车的舒适性,降低了车辆的行驶速度和道路的通行能力,加剧了车辆及桥台构造物的损坏。从台背过渡段路基产生沉陷的原因出发,通过建立三维空间模型,应用有限元法对产生不均匀沉降的可能影响因素进行了计算分析,并在此基础上给出了台背过渡段纵向处理的长度范围要求。     

桥头跳车原因分析及防治

根据已建成通车的道路使用情况,系统分析桥头产生跳车的原因,同时提出一些处治方法.     

机油LSPI性能评测方法研究

改善机油配方是解决直喷增压发动机低速早燃问题的有效手段之一,如何评价机油对低速早燃的影响尤为重要。本文简要介绍了机油LSPI性能评测方法的测试硬件、试验工况、量化方法,重点对方法精密度矩阵试验设计、试验数据处理以及精密度限值计算做了详细说明。本文使用SPSS软件对30个精密度试验结果建立了ANOVA分析模型,验证了在正确使用本方法下机油是对测试具有极强显著性影响的唯一因素,计算了中间精密度和再现性的限值,为后续使用本方法开展测试提供了必要依据。     

公路费用的构成与分摊

从经济学中引发费用公平的角度研究公路费用的构成和分摊；分析典型车型在等级道路上引发费用的构成；最后，对典型车型的各种引发费用进行初步的估算。     

汽车数字式巡航控制系统的研制

介绍了自行研制的汽车巡航控制系统，其主要由控制及调整开产、传感器、控制单元和执行机构组成；采用变参数ＰＩ控制算法，根据系统判别的汽车行驶状况（节气门开度和车速）和目标车速与实际车速之间的偏差大小来调整控制参数。该系统可以在汽车行驶过程中实现车速的自动控制，具有车速保持、微调以及恢复功能，有助于减轻驾驶员的疲劳程度，提高驾驶舒适性。     

纯氢燃料电池汽车性能的仿真

本文以由纯氢作燃料、采用串联式结构的燃料电池车用研究对象，通过仿真对车辆的部分参数和驾驶循环对车辆的性能影响进行了分析。在所分析的车辆参数中，动力系统效率的提高对车辆能量经济的改善最为有效，其次是车的总质量、空气阻力系数和滚动阻力系数减小的影响。在对原地起步加速特性的影响中，车重的减轻效果最为明显，其次是空气阻力系数和动阻力系数减小的影响。这些结论为燃料电池车动力系统的优化设计提供了依据。     

高速化汽车对检测维修的要求

汽车高速化是发展趋势，高速化汽车对车轮定位及检测维修提出更高要求，阐述了车轮定位新概念，介绍了车轮动不平衡、行驶跑偏、制动跑偏故障的产生原因及解决方法，另外，对高速化汽车的检测与维修提出了要求。     

Extended applications of track irregularity probabilistic model and vehicle–slab track coupled model on dynamics of railway systems

Track irregularities are inevitably in a process of stochastic evolution due to the uncertainty and continuity of wheel–rail interactions. For depicting the dynamic behaviours of vehicle–track coupling system caused by track random irregularities thoroughly, it is a necessity to develop a track irregularity probabilistic model to simulate rail surface irregularities with ergodic properties on amplitudes, wavelengths and probabilities, and to build a three-dimensional vehicle–track coupled model by properly considering the wheel–rail nonlinear contact mechanisms. In the present study, the vehicle–track coupled model is programmed by combining finite element method with wheel–rail coupling model firstly. Then, in light of the capability of power spectral density (PSD) in characterising amplitudes and wavelengths of stationary random signals, a track irregularity probabilistic model is presented to reveal and simulate the whole characteristics of track irregularity PSD. Finally, extended applications from three aspects, that is, extreme analysis, reliability analysis and response relationships between dynamic indices, are conducted to the evaluation and application of the proposed models.     

The effect of wheel set gyroscopic action on the hunting stability of high-speed trains

This study explores the effects of wheel set gyroscopic action on hunting stability by calculating linear and nonlinear critical speeds. First, a dynamic model for a high-speed vehicle with 23 degrees of freedom is developed by considering wheel set gyroscopic action. The linear and nonlinear critical speeds are calculated by eigenvalue analysis and drawing a bifurcation map, respectively. Two computer programs for linear and nonlinear stability analysis are developed. Second, based on an actual high-speed vehicle in China, the effects of wheel set gyroscopic action on hunting stability are quantitatively investigated using computer simulation. Furthermore, the difference between the effects of gyroscopic moments about the x-axis and z-axis is discussed. The results show that the moment about the x-axis is harmful to hunting stability, but the moment about the z-axis is beneficial to hunting stability. However, the integrated effect of these two moments can enhance the critical speeds and suppress the hunting motion.