子午线轮胎硫化过程仿真

根据对轮胎硫化程度的分析,利用ABAQUS软件对全钢子午线轮胎11.00R22.5建立了硫化温度场仿真模型,在此基础上利用阿累尼乌斯方程计算了轮胎各试验测温点处的硫化程度.仿真与硫化试验对比结果表明,仿真分析的硫化温度和硫化程度随时间的变化与试验结果相吻合,证明了所建有限元模型和计算方法的正确性.     

桥头跳车问题研究综述

该文在查阅大量资料基础上,对桥头过渡段沉降控制指标、地基沉降控制方法、台背填料处理方法及桥台和桥头过渡段路基刚柔过渡的方法等桥头跳车问题进行分析,简要介绍了其研究现状,并提出了研究方法和方向。     

铁路客运专线红石岩隧道防排水施工技术

合（肥）武（汉）铁路客运专线红石岩隧道位于大别山区，隧道穿过山间沟谷，地表水发育，谷地节理密集，局部地段岩体破碎，有一定的透水性，在施工过程中采取“防、排、堵相结合，因地制宜，综合治理”的原则，通过狠抓防排水细节施工，收到了良好的防水效果。     

Simulation of mixed gas formation for a spray-wall complex guided LPG direct injection engine

To obtain an ultralean air-fuel ratio and to reduce engine-out NOX and HC emissions induced by the richer mixture near the spark plug, a spray and wall complex guided combustion system has been developed by utilizing the fuel characteristics of LPG. The new combustion system configuration is optimized by using a commercial CFD code, FIRE V2013, and the reliability of the system has been experimentally demonstrated by Plane Laser-Induced Fluorescence (PLIF). The mixture formation in the new combustion system under part load (2,000 rpm) is numerically simulated. With an injection timing of 40°CA BTDC, the LPG spray which is injected from two upper holes, reaches the ignition point, and the other part of the LPG spray which is injected from the bottom hole, is directed to the ignition point through the vertical vortices at the same time. At the ignition timing of about 20°CA BTDC, the two-part mixtures have been shown to form a stable and richer stratified mixture around the ignition point, and the maximum global air-fuel ratio reaches to 60: 1.     

Robust control for four-wheel-independent-steering electric vehicle with steer-by-wire system

A four-wheel-independent-steering (4WIS) electric vehicle (EV) with steer-by-wire (SBW) system is proposed in this paper. The fast terminal sliding mode controller (FTSMC) is designed for the SBW system to suppress external disturbances. Taking unstructured and structured uncertainties into consideration, a robust controller is designed for the 4WIS EV utilizing μ synthesis approach and the controller order reduction is implemented based on Hankel-Norm approximation. Since sideslip angle is the feedback signal of robust controller and it is hard to measure, the extended Kalman filter (EKF) is employed to estimate sideslip angle. To evaluate the vehicle performance with the designed control system, step and sinusoidal steering maneuvers are simulated and analyzed. Simulation results show that the designed control system have good tracking ability, strong robust stability and good robust performance to improve vehicle stability and handing performance.     

Effective method for knock signal denoising in internal combustion engine

Uncontrolled expansion of combustion wave in spark ignited internal combustion engine causes knock effect which seriously degrades efficiency and lifetime of the engine. Thus, accurate knock detection and control are essential for obtaining a desired performance from the engine. Usually, knock sensor is used to detect this phenomenon but it has limited accuracy especially at engine high-speed rotations because of natural vibration and external noises. In this study an effective method based on Non-Local Mean (NLM) algorithm has been proposed to improve the knock detection accuracy. This method is evaluated based on four different indicators and four engine cylinders. The results show 52.9 % improvement in knock detection. Also feasibility of real time execution of this method based on embedded hardware has been studied.     

安龙铺隧道开挖过程动态数值模拟分析

以沪瑞国道主干线(贵州境)镇宁—胜境关高速公路安龙铺隧道为工程背景,利用有限元分析程序,对中壁CRD开挖法进行了数值模拟,分析研究开挖过程中隧道围岩应力场和位移场的变化。     

基于Digatron电池测试系统的锂电池温度寿命试验技术研究

本文主要论述了利用目前国际主流的Digatron电池测试分析系统,选取温度作为表征锂电池组寿命特性的参数,设计了电池组性能试验,通过实验数据分析得到了锂电池组寿命特性趋势,对于改善车辆电池控制管理策略具有指导意义。     

Transient characteristics of emissions during engine start/stop operation employing a conventional gasoline engine for HEV application

In this paper, we investigate the transient characteristics of combustion and emissions during engine start/stop operations in hybrid electric vehicle (HEV) applications. Hydrocarbon (HC) emissions during the initial 2^nd∼9^th cycles are found to be significantly greater when the engine is quickly started under the original engine calibration mode. Lower intake manifold absolute pressure (MAP) was also found to cause larger residual gas dilution and poor combustion, resulting in a higher HC concentration when the cranking speed was increased. The post-catalyst HC concentration was found in the way of initially decrease and then to increase again as the cranking speed was increased. A lowest concentration value was achieved at a cranking speed of 1000 r/min. Engine shut-down by fuel cut-off was shown to produce lower emissions than shut-down by ignition cut-off as one can avoid misfire of the last fuel injection cycle. The fuel deposited during the stop process seems to impact engine restart enrichment mostly during the initial 0.7 s for this engine, whose performance is dominated by the MAP transition characteristic and the time coefficient for fuel vaporization in this time period     

武汉阳逻长江大桥北锚碇基坑开挖施工技术

锚碇作为承力结构的重要部分,是悬索桥的重点控制性工程。介绍武汉阳逻长江大桥的北锚碇开挖与基坑支护的施工情况,着重介绍基坑土石方开挖(爆破)、弃渣运输、基坑边坡防护与排水以及锚碇安全检测等关键施工技术。