Development of a hydraulic limited slip differential system using a pressure generator

The limited slip differential (LSD) is a device that enables the driving force to be transmitted from one slipping wheel to the other by temporarily restraining the differential function when unwanted slipping occurs on muddy or icy roads. Many types of LSD have been developed, such as mechanical lock, disk clutch, viscous coupling, torsen and multiple clutch. This study designed a new type of hydraulic LSD using a pressure generator base on a trochoid gear pump and evaluated the performance of the new design.     

Pressure drop and heat transfer of catalyzed diesel particulate filters due to changes in soot loading and flow rate

When soot particles are loaded in a diesel particulate filter, it causes increase in back pressure of the exhaust system. To minimize this pressure drop due to DPF, the filter needs to be regenerated after a certain amount of soot has been accumulated. It is crucial to estimate the correct amount of soot that has been accumulated by measuring the differential pressure. It is also important to understand changes in pressure drop due to flow rate variations of the exhaust gas, since the pressure drop would be influenced by the exhaust flow rate as well as the amount of soot. Furthermore, the heat transfer characteristics of the catalyzed diesel particulate filter (CDPF) are another major issue, as the filter is occasionally exposed to high temperature gas. This study presents the characteristics of pressure drop according to the variation of soot loading and the mass flow rate in CDPF. In addition, heat transfer characteristics in the filter was investigated when a high temperature gas flows into the CDPF. Tests were performed in several CDPF samples having varying amounts of catalyst coating. Experimental results indicate that rig-based experiments are useful in understanding the characteristics of pressure drop in the CDPF. In the cake filtration region, a pressure drop has a proportional relationship according to soot loading and mass flow rate. It was found that an increased catalyst coating may lead to enhanced convective heat transfer.     

利用ADAM模块开发气源监控系统

叙述某装置的原料气源罐的压力采集与控制系统,该系统硬件主要由研华工控机和ADAM4000模块组成,软件在WindowsXP平台下利用VC编制,其界面友好,操作方便,试验证明该系统能实时采集各分布点的气源压力,并得到满意的压力控制精度。     

ZK4型电空转辙机与ZK3-A型的比较

电空转辙机是铁路驼峰编组场主要的道岔转换设备,目前驼峰编组场使用的电空转辙机有 ZK3-A 型和 ZK4型两种机型,ZK3系列电空转辙机在八十年代初投入使用,虽经过多次改进,在使用中仍然存在一系列问题,正在逐步被 ZK4型电空转辙机所替代。     

某轿车离合器不平整度引起的爬行抖动研究

某轿车采用双离合变速器,在起步爬行工况存在明显的整车抖动现象,并且导致变速器异响。本文通过试验分析手段发现整车抖动频率与发动机转速、输入轴转速以及转速差相关,结合离合器颤振的发生机理和发生条件,得出离合器执行过程中压力变化引起的颤振是整车爬行抖动的主要原因,离合器压力变化主要与本身结构参数—离合器不平整度(MGF)相关,通过整车试验方法和主观评价方法分析不同的离合器MGF值对整车抖动的影响,从而获得最优MGF值,有效解决该车抖动问题。     

日用水管系压力平衡及流量控制对策研究

通过对日用水系统供水压力平衡及流量控制存在的问题及产生的技术原因进行分析,针对性地提出了相应对策,并进行了一定的可行性理论定性分析,为日用水系统供水压力平衡及流量控制提供了理论基础。     

局部砰击载荷预报的规范算法研究与分析

通过比较不同船级社砰击规范的适用范围及要求,对砰击压力展开研究。通过对实例船型的计算和分析,比较不同规范计算得到的艏底和外飘砰击压力。分解砰击压力计算的经验公式,提出对砰击压力有显著影响的参数,比较这些参数对砰击压力影响的程度,以指导砰击载荷作用下船体局部结构的设计实践。     

Efficient time-domain approach for hydroelastic-structural analysis including hydrodynamic pressure distribution on a moored SFT

This study investigates the hydroelastic analysis of a moored SFT (submerged floating tunnel) and the corresponding hydrodynamic pressure distribution under wave excitations. Time-domain discrete-module-beam (DMB) method, in which an elastic structure is modeled by multiple sub-bodies with beam elements, is employed to express the deformable tunnel with multiple mooring lines. Moreover, the top-down scheme is also adopted for detailed structure analyses with less computational cost, which applies the calculated hydrodynamic pressure distribution over SFT's surface to the three-dimensional finite element model. The hydrodynamic pressure includes both wave-induced diffraction pressure and motion-induced radiation pressure. For the validation of the developed numerical approach, comparisons are made with computationally intensive hydroelastic-structural direct-coupled method, two-dimensional wave flume experiment, and independently developed inhouse moored-SFT-simulation program. Furthermore, the influences of flexural motions with buoyancy-weight ratio (BWR) (or bending stiffness) and regular/irregular wave conditions on the dynamic pressure distribution and the resulting local stresses are investigated.     

多种参数影响下的船舶艉轴承润滑性能分析

针对安装误差导致的轴颈倾斜角、主轴转速、艉轴工作环境温度等因素对船舶艉轴承润滑性能影响的问题,以某散货船为研究对象,基于Reynolds边界条件,运用有限差分法对Reynolds方程进行求解,通过数值分析软件MATLAB进行编程,获得不同工况下艉轴承的润滑模型。进而对多种参数影响下的油膜压力和油膜厚度差异进行对比分析。结果表明:考虑轴颈倾斜角的情况下,轴颈倾角逐步增大,油膜压力峰值与轴颈倾角呈现正相关关系,最小油膜厚度减小速度先快后慢;主机在不同工况下,油膜压力峰值与主轴转速呈现负相关关系,最小油膜厚度与主轴转速则呈现出一种近似正比的关系;当艉轴工作环境温度变化时,随着温度的升高,最大油膜压力逐渐增大,最小油膜厚度变化趋势则相反,逐渐向减小的方向发展。     

基于制动器耗散的ABS实验方法研究

汽车防抱死制动系统(简称ABS)是重要的汽车主动安全性装置,是汽车制动电子技术的基础。ABS控制策略是ABS的核心技术,掌握控制策略的设计和匹配,对于自主开发ABS和进一步开展汽车主动安全性理论有着重要的现实意义。本文基于制动器耗散功率最大为目标的ABS控制理论,对制动器的TQ P(制动力矩、压力)动态特性进行了深入的研究,得出了相应的结论,找出制动器制动力矩与油压的关系曲线。