高速公路沥青混凝土路面破损状况评价方法的缺陷及改进

以广东省多条高速公路沥青混凝土路面的路况普查数据为基础,分析了目前我国高速公路沥青混凝土路面破损状况评价方法的诸多不足,在此基础上提出了高速公路沥青混凝土路面破损状况的合理评价指标,即路面车辙代表深度、路面裂缝率以及路面修补率。此外,应用基于三角白化权函数的灰色聚类评估方法对沥青混凝土路面的破损状况进行了综合评定,为我国高速公路沥青混凝土路面养护质量的评定及养护对策的制定提供了参考依据。     

关中国省干线公路沥青路面预防性养护阈值研究

基于关中地区国省干线公路典型养护工程检测结果,采用S型曲线模型,对PCI、RQI等路况评价指标进行回归分析,拟合路面性能衰减曲线,对比不同组合下的PCI、RQI模型参数,分析面层厚度及交通量对预防性养护PCI、RQI阈值的影响。研究表明:S型路面性能衰减模型与路面性能衰减规律吻合度佳,其相关系数R2高于0.95;路面性能衰减函数中,|PCI"|、|RQI"|最大值对应的路况评价指标可作为预防性养护阈值,其中,预防性养护PCI阈值取85.0,RQI阈值取84.0。     

拐点理论在沥青混凝土路面预防性养护时机确定中的应用

综述国内外有关沥青混凝土路面预防性养护时机确定的方法,指出单指标界定模型的不合理性;结合目前国内技术规范中路面性能评价指标,提出了针对预防性养护的路面综合评定模型;利用综合评定模型和实测数据借助EXCEL宏形成云南省典型高速公路沥青混凝土路面的衰变曲线三级模型,提出沥青混凝土路面预防性养护时机的衰变曲线拐点理论,并结合单指标预防性养护区间验证了拐点理论应用的正确性.     

沈大高速公路路面使用性能养护综合评价模型的研究

以沈阳至大连高速公路路况普查的数据为基础，考虑路面性能参数的概率分布特性，建立了高速公路沥青路面使用性能养护综合评价模型，并通过产例将其与国内外模型进行了对比分析，验证了其实用性。然后通过进一步研究建立了此模型与养护经济费用的关系，找出了路面养护费用增长的敏感阶段，建立基于路况综合评价的路面养护优先级别，为高速公路养护优先排序提供了一个简捷的参考方法，最后应用马尔可夫过程建模方法，建立了路况综合评价随时间衰变的概率预测矩阵，使之可供养费用分析之用，通过以上研究，此模型可为高速公路沥青路面的养护评价，养护对策的优先排序，养护资金的优化决策分析提供参考。     

高速公路沥青混凝土路面使用性能评价及养护决策研究

高速公路沥青混凝土路面使用状况直接决定着路面的养护决策,在规范已有的评价指标的基础上建立了车辙的评价指标及指标建议值,提出了在高温多雨地区路面综合评价指数PQ I模型各指标权重的建议值,并采用决策树模型建立了高速公路沥青混凝土路面养护决策模型。     

高速公路沥青混凝土路面使用性能评价及养护决策研究

高速公路沥青混凝土路面使用状况直接决定着路面的养护决策,在规范已有的评价指标的基础上建立了车辙的评价指标及指标建议值,提出了在高温多雨地区路面综合评价指数PQI模型各指标权重的建议值,并采用决策树模型建立了高速公路沥青混凝土路面养护决策模型.     

高速公路沥青混凝土路面维修罩面成套技术研究

本研究以河北省已建成的高速公路为工程依托,从高速公路沥青混凝土路面路况跟踪观测,路面性能评价与养护决策方法,维修罩面设计程序与方法,维修罩面施工技术,维修罩面招标、投标与合同管理等方面进行研究,提出了适合高速公路路面性能评价的指标和模型,开发并初步完成高速公路沥青混凝土路面维修罩面成套技术。     

广东省普通国省道典型路面结构衰变规律及养护技术

针对广东省普通国省道路面质量指数(PQI)、路况指数(PCI)、行驶质量指数(RQI)和车辙深度指数(RDI)等指标,研究了典型路面结构的路况衰变规律,分析了路面养护指标与使用年限的相关性关系,提出了水泥路面的二次型衰变模型和沥青路面的三折线衰变模型。通过历年数据分析表明:旧水泥路面加铺5 cm及以下沥青面层是短期提高路面技术指标的养护措施;旧水泥混凝土路面加铺8~10 cm沥青面层可有效提高路面技术指标,减缓反射裂缝的产生,是水泥路面养护投资最少的养护措施;旧水泥路面破碎后加铺新水泥混凝土的养护方案,适用于重载交通或公路纵坡较大的路面改造;原沥青路面铣刨后加铺新沥青面层,路面使用到第4年,路况指标由优等状态发展为良等状态,是实施预防性养护的最佳时机。     

高速公路沥青路面破损状况评价指标体系研究

依据湖南省多条高速公路沥青路面的路况调查数据,分析了目前我国高速公路沥青路面破损状况评价方法的不足,提出了基于三角白化权函数灰色聚类法的路面车辙深度、路面裂缝率,路面坑槽率和路面修补率四个指标的沥青路面破损状况评估模型,并以临长高速公路工程实例应用表明该评价模型的可行性,为沥青路面养护质量的评定及养护对策的制定提供了参考依据.     

江苏省高速公路沥青路面预防性养护技术分析与研究

预防性养护最佳时机、预防性养护方案的选择是沥青混凝土路面预防性养护技术的重要内容.对江苏省高速公路沥青路面性能衰减特征进行分析,得出其最佳预防性养护时机范围,在此基础上,综合分析江苏省高速公路沥青路面性能、气候条件和交通量状况及各项预防性养护措施的适用性,提出江苏省高速公路沥青路面预防性养护技术的选择指南,对江苏省沥青...     

基于效用模型的沥青路面预防性养护研究

预防性养护是一种高标准养护方式。在预防性养护中,养护时机的选择至关重要。基于此,提出了以建立养护短期效用预测模型来进行养护时机的选择,该模型通过对路面性能短期提高值以及养护后路面性能衰变规律的预测,能较为精确地获得养护后路面性能曲线,以及养护短期效益值,进而运用效益-费用分析法可以较方便而准确地确定最佳养护时机和养护方案。养护效用预测模型为预防性养护的研究提供了新思路,具有重大的理论意义和实际意义。     

地下掘进之地盘——机械互制与可挖指标研探

地下机械式之掘削效率乃为进度、成本及品控之关键要因,一般工程思考皆多考虑工法与机型对应各类不同地层之"可挖性"作探讨,即针对地质材料选择适应之切削面盘,鲜能再对地盘——机械开挖互制行为作一"适确性"研析,而本研究先由微观之量纲分析及力学尺度探讨并建立指标,运用至巨观推力、扭矩之施工良窳、可挖性及正常施作或异况破坏之分析。机械式掘削接触地质与产生之互制行为相异性极大,故由地质破坏特征作为切削地盘材料之分类,藉此提供该广义式之探讨方针;其次在施工判准所建立之可挖指标上,使用量纲分析方法进行具代表力学行为之因子解析,作为建置指标的依据;再者,应用现场调查以资搜机械式开挖所量测的推进力系数值,进而佐证其适确性,最终完整研析机械式掘削开挖之行为与可挖性指标之应用。     

Experimental study of the physical and chemical characteristics of biodiesel blended fuel using ultrasonic energy irradiation

The purpose of this study is to understand the physical and chemical characteristics of biodiesel blended fuel reformed by ultrasonic energy irradiation. To do this, a mixture of commercial diesel fuel and biodiesel was compared and analyzed according to whether or not ultrasonic energy irradiation was performed and the duration of irradiation. The results of the experiments indicate that when ultrasonic energy irradiation was performed on biodiesel blended fuel, its viscosity decreased by 3–7%. In the case of BD20, when ultrasonic energy irradiation was performed, its Sauter mean diameter (SMD) dropped by 12% on average. As the irradiation duration increased, the volume ratio of olefins increased up to a maximum of 2.7%, and the higher heating value increased to a maximum of 5.8%. On the contrary, the ratio of aromatics decreased by a maximum of 2.7%, and BI decreased by a maximum of 7%.     

快速公交(BRT)智能系统框架结构研究

以智能交通系统（ITS）为研究背景,针对快速公交系统的运营模式及主要特征,提出了适合我国公交现状的快速公交智能系统框架结构,同时对智能系统进行了较为翔实的分析和设计。     

Effect of intake valve swirl on fuel-gas mixing and subsequent combustion in a CAI engine

A fully three-dimensional model was used to investigate the optimal value for intake valve lift in a CAI engine. Uniform mixing in the engine is a key parameter that affects the auto-ignition reliability and thermal efficiency. The method of intake of the air supply often determines the uniformity (or quality) of the fuel-air mixture. In this paper, four strategies were applied for controlling the swirl intensity of intake air. The variation of the intake valve lift induces different swirling and tumbling intensities. Both experimental data and 1D WAVE software (Ricardo, Co.) were coupled with the 3D model to provide pressure and temperature boundary conditions. The initial condition of the EGR mass fraction was also provided by the 1D model. The benchmark scenario (Case 1) was considered as a valve lift with 2 mm for all intake valves. We found that an intake valve lift of 6 mm with the other intake valve closed (i.e., Case 5) yielded the largest swirling (helical motion in the axial direction) and tumbling, which in turn rendered optimal fuel-gas mixing. We also found that fuel distribution affected the auto-ignition sites (or spot). The better the mixing, the greater the gas temperature and combustion efficiency achieved, as seen in Case 5. The NOx level, however, was increased due to the gas temperature. The optimal operating condition is selected from the viewpoints of environmental protection and combustion efficiency.     

Design of Integrated Chassis Control logics for AFS and ESP

The performance of most electronic chassis control systems in the past has been optimized individually. Recently, a great research effort has been dedicated to the integration of chassis control systems in an effort to improve the vehicle performance. This involves orchestration of individual control modules so that they can jointly contribute to the enhancement of their control effect. In this research, two integrated control logics for AFS (Active Front Steering) and ESP (Electronic Stability Program) have been developed. Of the two logics, one uses a supervisor that rules over the individual modules. The other logic uses a CL (Characteristic Locus) method, which is a frequency-domain multivariable control technique. The two logics have been tested under various driving conditions to investigate their control effects. The results indicate that the proposed integrated control logics can yield vehicle performance that is superior to that of the individual control modules without any integration scheme.     

Fuzzy and adaptive fuzzy control for the automobiles’ active suspension system

Two typical criteria for good vehicle suspension performance are their ability to provide good road handling and increased passenger comfort. The main disturbance affecting these two criteria is terrain irregularities. Active suspension control systems reduce these undesirable effects by isolating car body motion from vibrations at the wheels. This paper describes fuzzy and adaptive fuzzy control (AFC) schemes for the automobile active suspension system (ASS). The design objective is to provide smooth vertical motion so as to achieve the road holding and riding comfort over a wide range of road profiles. The efficacy of the proposed control schemes is demonstrated via simulations. With respect to the optimal linear quadratic regulator (LQR), it is shown that superior results have been achieved by the AFC.     

Fuzzy and adaptive fuzzy control for the automobiles' active suspension system

Two typical criteria for good vehicle suspension performance are their ability to provide good road handling and increased passenger comfort. The main disturbance affecting these two criteria is terrain irregularities. Active suspension control systems reduce these undesirable effects by isolating car body motion from vibrations at the wheels. This paper describes fuzzy and adaptive fuzzy control (AFC) schemes for the automobile active suspension system (ASS). The design objective is to provide smooth vertical motion so as to achieve the road holding and riding comfort over a wide range of road profiles. The efficacy of the proposed control schemes is demonstrated via simulations. With respect to the optimal linear quadratic regulator (LQR), it is shown that superior results have been achieved by the AFC.     

汽车电子控制转向技术的发展趋势

电动转向技术符合汽车机电一体化的设计思想,由于其技术先进,性能优越,未来必将成为动力转向技术的主流,线控动力转向系统将是转向系统的发展方向。本文综述了国内外汽车电子控制动力转向技术的发展及研究现状,介绍了电动助力转向系统的工作原理、组成及特点,并阐述了两项技术今后的发展趋势。     

Design of an energy management strategy for parallel hybrid electric vehicles using a logic threshold and instantaneous optimization method

A novel parallel hybrid electric vehicle (PHEV) configuration consisting of an extra one-way clutch and an automatic mechanical transmission (AMT) is taken as the study subject of this paper. An energy management strategy (EMS) combining a logic threshold approach and an instantaneous optimization algorithm is developed for the investigated PHEV. The objective of this EMS is to achieve acceptable vehicle performance and drivability requirements while simultaneously maximizing engine fuel economy and maintaining the battery state of charge (SOC) in its rational operation range at all times. Under the MATLAB/Simulink environment, a computer simulation model of the studied PHEV is established using the bench test results. Simulation results for the behavior of the engine, motor, and battery illustrate the potential of the proposed control strategy in terms of fuel economy and in keeping the deviations of SOC at a low level.