现代汽车自动空调系统工作原理及正确使用与维护(十二)

<正>汽车自动空调系统诊断思路与定期维护项目汽车空调系统的故障,由于不同品牌车辆的结构差异,其故障现象、内容及发生频率有所不同,按故障类型可分为制冷循环系统和控制系统故障两大类。不过因制冷循环系统与控制系统的故障有着相关的联系,往往会导致故障现象不是很清晰,对故障难以定位,从而造成故障判断的准确性不高。     

雷诺科雷傲配电及开关保护单元(UPC)原理及维修

<正>一、元件组成及元件位置图(如图1所示)1.UPC保护开关模块单元通过车辆的多功能网络接收到从每个电子控制单元请求的信号和从各种各样传感器的输入信号。这些信号     

准周期激励非线性隔振系统的混沌研究

建立了准周期激励下非线性隔振系统的模型;应用Poincare映射方法对系统进行降维处理后,在Poincare截面上分析了系统稳定流形和不稳定流形的行为.应用Melnikov方法确定了系统产生混沌的参数区域.结果表明双曲不变环面的稳定流形和不稳定流形之间同宿横截相交是导致该系统产生混沌的根本原因,并给出了系统出现混沌时的相图、Poincare截面图,计算了Lyapunov指数.     

钢夹层板数值模拟技术

Sandwich plate systems (SPS) are advanced materials that have begun to receive extensive attention in naval architecture and ocean engineering. At present, according to the rules of classification societies, a mixture of shell and solid elements are required to simulate an SPS. Based on the principle of stiffness decomposition, a new numerical simulation method for shell elements was proposed. In accordance with the principle of stiffness decomposition, the total stiffness can be decomposed into the bending stiffness and shear stiffness. Displacement and stress response related to bending stiffness was calculated with the laminated shell element. Displacement and stress response due to shear was calculated by use of a computational code write by FORTRAN language. Then the total displacement and stress response for the SPS was obtained by adding together these two parts of total displacement and stress. Finally, a rectangular SPS plate and a double-bottom structure were used for a simulation. The results show that the deflection simulated by the elements proposed in the paper is larger than the same simulated by solid elements and the analytical solution according to Hoff theory and approximate to the same simulated by the mixture of shell-solid elements, and the stress simulated by the elements proposed in the paper is approximate to the other simulating methods. So compared with calculations based on a mixture of shell and solid elements, the numerical simulation method given in the paper is more efficient and easier to do.     

VLCC改装的几点总结

文章详细介绍了最具代表性的大型油轮VLCC改装VLOC的基本情况、改装原理、施工方案、施工中常见的难点和技术控制要点,以及大型油轮改装的安全和质量控制的重点,可供业内人士参考。     

船用火灾报警控制器的工作原理与适用性

船用火灾报警控制器是智能火灾报警控制器,集报警与联动控制于一体,控制器具有多项智能特性,诸如漂移补偿、平滑处理、灵敏度调整、自优化预报警、综合多元探测器探测及维修警告等。能够准确探测到早期火灾的发生。     

某型隔振系统弹性支撑高度调整的优化分析

考虑到隔振器的寿命与受力状况有一定关系,为了使隔振器的受力一致,对系统进行静力分析,得出一组解系,然后线性变换解系,达到优化目的。实例计算表明,优化后的隔振器受力能达到均匀,有效减少了受力对隔振器寿命的影响。     

GPS-RTK技术在港口水下工程的应用

本文结合在港口与航道工程(主要是水下工程)中GPS测量控制的运用,介绍了GPS-RTK测量技术在港口与航道工程水下工程的应用及实际施工中的一些体会(如施工船舶基坑开挖定位、基床整平、水深测量等)     

门机齿条变幅机构排装的原理与工艺要点

门机变幅机构多为工作性带载变幅。齿轮齿条式变幅传动机构与其他传动形式相比,具有传动效率高、制造简单、安装方便的优点,因而得到了广泛的应用。     

DPG500铺轨机组布枕机构优化与设计

DPG500长轨条铺轨机组的核心部分为轨枕布放系统。简要分析比较国外几种铺轨机组的轨枕布放系统,重点介绍DPG500长轨条铺轨机组采用的曲柄连杆送枕、垂直布枕的轨枕布放系统及其控制系统,阐述其工作原理并分析其优缺点。