汽车发动机冷却水泵中半开式叶轮锥面角度专用量具设计

汽车发动机冷却水泵是汽车发动机冷却系统的重要组成部分。其作用是使冷却液循环流动降低发动机运行温度。本文介绍了汽车发动机冷却水泵使用的半开式叶轮锥面角度的测量方法,量具的设计原理、使用方法以及判定准则。     

柴油机冷却水泵轴断裂问题的研究

冷却系统属于整个柴油机装置中的重要系统,其中冷却水泵为该系统的关键部件。近期多种型号的柴油机配备的冷却水泵多发断轴的问题,给柴油机正常工作带来了严重影响。因为缺少相应规范和标准,虽然经过几轮整改工作,但是冷却水泵的断轴问题依旧没能避免。该文设计了包括冷却水泵的柴油机轴类零部件扭转及振动模型,如异向振型受发动机激励,水泵轴系的扭振过程附加应力载荷将大于许用应力,引起疲劳断裂的情况。     

电子节气门硬件在环仿真测试方法研究

电子节气门被广泛地应用于汽车发动机中,其设计越来越受到重视.采用硬件在环仿真测试可大大缩短电子节气门的研发、标定时间.借助汽车电控系统快速原型开发环境(MACS565),建立了电子节气门的硬件在环仿真测试平台.利用Matlab/Simulink建立了仿真测试模型,实现了电子节气门硬件在环仿真和性能测试.利用此平台完成了某型号电子节气门传感器输出特性的测试方法研究及相关参数的测定工作.该测试平台为电子节气门新产品的开发与性能检测提供了测试手段,同时可作为产品在线质量检测系统的原型.     

汽车发动机冷却水泵中半开式叶轮锥面测量圆高度检具设计

本文介绍了汽车发动机冷却水泵中半开式叶轮锥面测量圆高度的测量方法和量检具的设计原理和使用方法及判定准则。     

发动机温度过高的故障诊断与排除

汽车发动机的冷却系多为冷却水强制循环系统,即利用水泵增加冷却液的压力,强制冷却液在发动机中循环流动。发动机冷却系统是维持发动机处在正常工作温度的关键系统,此系统出现故障往往会造成发动机无法正常工作、机件损害或粘缸抱瓦等恶性事故。发动机冷却系常见的故障就是发动机温度过高,故障部位主要有水泵、散热器、冷却风扇、节温器、发动机机体和气缸盖中的水套以及附属装置等。     

汽车发动机检测分析仪设计

汽车发动机检测分析仪器是发动机性能检测、故障诊断的重要设备,汽车发动机的一般参数检测相对容易些,而点火电压变化快,持续时间短,成为汽车性能分析仪器中的关键技术,我们设计的汽车发动机点火测试电路较好地解决了这一技术难题,使汽车发动机分析仪器的性能更加完善.     

中央空调系统水泵变频运行性能的实验研究和节能分析

针对湖南某宾馆空调水泵系统的变频性能进行了实验研究,对变频控制技术在中央空调水系统中的应用进行了分析和探讨,认为对冷水泵和冷却水泵采用变频控制能起到显著的节能效果.     

解析汽车发动机冷却系的维修

发动机冷却系可以充分冷却发动机,保证其工作温度符合相关要求,冷却系统包括诸多的组成部分,如风扇、散热器、水泵、节温器等,如果有故障出现于冷却系统中,就会影响到发动机的正常运行,出现过热问题,降低发动机功率,早燃和爆燃容易出现,影响到润滑效果。针对这些情况,就需要对汽车发动机冷却系统进行维护和修理工作,确保汽车发动机冷却系可以正常的运行。     

发动机冷却系的前端进风需求计算

为保障汽车发动机冷却效果,需在整车开发项目前期就对前端进风提出量化需求。本文通过提炼物理数学模型,结合发动机台架试验数据与汽车运行受力分析,得到不同工况下的发动机散热量,并据此算出前端进风量需求。将此方法应用于某全新车型的项目开发,以CFD数值模拟校验结果为设计调整依据,最终顺利通过了在环模风洞中进行的发动机冷却性能试验,证明该物理数学模型具有较好的预测能力。     

一种汽车发动机台架测试流量计计量性能监控方案

汽车发动机进气流量测量是发动机台架测试的重要项目,其测量结果直接影响排放的结果.文章制定了一种针对汽车发动机台架测试流量计计量性能监控的方案.该方案研制了专门的核查和修正装置,通过内部核查、外部检定和二次修正相结合的方式,对流量计的计量性能实施监控.当流量计的计量性能出现偏离时,通过二次修正模块对流量计进行修正,使其满...     

一类分数阶非线性时滞系统的稳定性与镇定（英）

稳定性是控制系统分析与设计的基础．探索分数阶系统,特别是分数阶时滞非线性系统的稳定性条件是控制理论与工程领域中的难点问题．本文研究了一类分数阶非线性时滞系统的稳定性和镇定．通过将原系统转化成等价的分数阶积分系统,再借助不等式放缩技术,提出了一个有效且形式简单的确保该类系统稳定新的时滞无关稳定性准则．根据所得的稳定条件,提出了基于时滞线性反馈控制器的镇定控制方法．最后,数值实例验证了所得结果的有效性．此外,本文所使用的方法可以推广和应用于其他类型的分数阶系统的稳定性和镇定控制．     

System thinking applied to near misses: a review of industry-wide near miss reporting systems

Abstract

Learning from near misses is an important component of maintaining safe work systems. Within safety science it is widely accepted that a systems approach is the most appropriate for analysing incidents in sociotechnical systems. The aim of this article is to determine whether industry-level near miss reporting systems are consistent with systems thinking. Twenty systems were identified, from a range of work domains, and were evaluated against systems thinking-based criteria. While none of the reporting systems fulfilled the full set of criteria, all are able to identify actors and contributing factors proximal to events in sociotechnical systems and many capture information on how accidents were prevented. It is concluded that the explanatory power of near miss reporting systems is limited by the systems currently used to gather data. The article closes by outlining a research agenda designed to ensure that near miss reporting systems can fully align with the systems approach.     

Classification of stable configurations of plane mirrors

We have studied the stability of systems of plane mirrors by using a new way to describe ray transformations caused by such systems. All stable systems comprising as many as three mirrors are described and classified. Besides the well-known corner cube, infinitely many stable retroreflecting and direction-preserving three-mirror systems have been found.     

非线性振动的模态方法

自从60年代Rosenberg 提出非线性振动系统模态概念以来,国外许多学者对之进行了大量的研究,取得了不少成果。但迄今为止,只研究了保守系统的模态,利用模态进行研究的也仅仅是系统的周期响应。我们将现有的非线性系统模态的概念加以发展,较系统地提出了一种利用非线性系统的模态研究非线性振动问题的方法——非线性振动的模态方法。该方法不仅适用于保守系统,而且适用于非保守自治系统和非自治系统;既可用来研究系统的周期响应,也可用来研究系统的非周期响应。     

一种基于流形学习和 KNN算法的柴油机工况识别方法

不同负荷状态下的柴油机振动、温度、转速等信号显著不同,而机组故障信号特征往往淹没在随负荷变化而剧烈变化的信号中,因此变负荷状态下的柴油机故障监测诊断难度较大,一直困扰着柴油机的实际故障诊断工作。本文提出了一种基于流形学习和KNN算法的柴油机工况识别方法,为柴油机变负荷工况下故障监测预警打下基础。方法融合机组的多源信号特征构建特征向量,通过流形学习t-分布邻域嵌入算法（t-SNE）实现特征向量的维数约简和敏感特征提取,采用K最近邻分类算法（KNN）完成柴油机运行负荷状态的自动分类。正常及故障状态下的柴油机信号验证了方法的有效性和实用性。     

The Diffraction Theory of the Aberrations of Stigmatic Orthomorphic Optical or Electron Optical Systems Containing Toric Lenses or Quadrupoles

The diffraction theory of the aberrations of optical systems with an axis of rotational symmetry is now thoroughly established, and the extension to kindred electron optical systems is straightforward. In electron optics, however, certain types of systems containing quadrupoles are of importance, and such systems suffer from aberrations which affect only very oblique rays in axially symmetrical systems. The distortions of the wave surface which correspond to these new aberrations are listed in the present note, and Nijboer's expressions for the consequent disturbances in the image plane of a rotationally symmetrical system are supplemented accordingly. Only the special case—which is, nevertheless, an important one—of stigmatic systems, producing an image free of first-order distortion?, is considered. The analysis is applicable to electron optical orthogonal systems containing quadrupoles and optical systems containing parallel toric lenses alike.     

Performance comparison of multiple product kanban control systems

Kanban control systems have been around for decades and have been used to control work-in-process of manufacturing systems. Lately many variations of the basic control system have been developed; however, much of the work in the development and comparison of control systems has focused on a single-stage manufacturing system producing a single product type. In this research, we present procedures for optimising multiple product kanban control systems, namely Base Stock, Traditional Kanban Control System and Extended Kanban Control System (both dedicated and shared type). We then conduct a detailed simulation study to compare the performance of the systems using a common total cost measure. Numerical results show that the dedicated and shared-extended kanban control systems outperform the other two systems. The study also shows that in spite of their different schematics and contrary to conventional wisdom, the performance of dedicated and shared-extended kanban control systems doesn’t differ much.     

聚醚型聚氨酯橡胶硫化性能的研究

研究了硫磺硫化体系和过氧化二异丙苯（DCP）硫化体系对聚醚型聚氨酯橡胶性能的影响。结果表明：硫磺硫化体系可以延长胶料的焦烧时间、正硫化时间,缩短最低扭矩,延长最高扭矩,提高胶料的阻尼性能;而DCP硫化体系可以显著降低胶料的压缩永久变形和扯断伸长率。     

Recurrent motions and global attractors of non-autonomous Lorenz systems

This paper is devoted to the study of dynamics of non-autonomous Lorenz systems. These systems are formulated and investigated in the context of non-autonomous dynamical systems. First, we prove that such systems admit a compact global attractor and characterize its structure. Then, we obtain conditions of convergence, under which all solutions of the non-autonomous Lorenz systems approach a point attractor. Third, we derive a criterion for existence of almost periodic, quasi-periodic, periodic, and recurrent motions. Finally, we prove a global averaging principle for non-autonomous Lorenz systems.