一起与燃油压力调节器有关的发动机故障分析

发动机燃油压力调节器简称调压阀,结构虽然简单,但是作用很大。在电喷发动机中,喷油量是重点控制对象,是一个很复杂的控制过程。影响喷油量的诸多因素中,可控的有两个,即喷油脉宽和喷油压力,脉宽由发动机ECU根据发动机工况等参数进行控制,喷油压力则由调压阀控制。调压阀的故障对发动机性能的影响往往比较隐蔽,容易被忽略。在多起汽车维修案列中,故障都与调压阀的故障有关。文章目的是通过对调压阀的结构、原理以及输出特性等进行分析,为在汽车实际维修中快速找准故障、排除故障提供必要的知识。并通过一个具体故障实例进行分析说明。     

车辆换挡用数字比例溢流阀试验研究

该文改变PWM控制信号的频率和阻尼孔直径,对数字比例溢流阀进行了试验研究.通过多组试验数据对比,选定高速开关阀的工作频率以及阻尼孔直径大小,并利用MATLAB软件对采集的数据进行处理,得到数字比例溢流阚的输出压力随占空比变化的规律曲线.试验结果表明:PWM控制信号的频率为50 Hz时,既能保证有效占空比调节范围,又能满足系统的频率响应性能;阻尼孔直径为1 mm时,满足数字比例溢流阀的压力调节范围.     

一起与燃油压力调节器关的动机故障分析有发

发动机燃油压力调节器简称调压阀,结构虽然简对象,是一个很复杂的控制过程.影响喷油量的诸多因素中, ECU 根据发动机工况等参数进行控制,喷油压力则由调压阀控容易被忽略.在多起汽车维修案列中,故障都与调压阀的故障性等进行分析,为在汽车实际维修中快速找准故障、排除故障提单,但是作用很大.在电喷发动机中,喷油量是重点控制可控的有两个,即喷油脉宽和喷油压力,脉宽由发动机制.调压阀的故障对发动机性能的影响往往比较隐蔽,有关.文章目的是通过对调压阀的结构、原理以及输出特供必要的知识.并通过一个具体故障实例进行分析说明     

节流式和溢流式液压耗能阻尼器性能比较研究

主要介绍了3种分别采用阻尼孔、溢流阀、溢流节流阀耗能的液压阻尼器,及其各自的结构、特点、工作原理,并对其阻尼力的产生和耗能情况进行理论分析。     

基于模拟退火算法的多孔式液压缓冲器阻尼孔优化

提出了基于模拟退火算法的阻尼孔组合优化方案,实现了多孔式液压缓冲器的优化设计。根据缓冲器缓冲过程中的受力状态和孔口流量特性，建立了多孔式缓冲器缓冲过程的动态数学模型；以阻尼孔直径、阻尼孔间距和阻尼孔数量为优化变量，基于缓冲器动态数学模型与模拟退火算法，建立了阻尼孔组合优化求解模型；根据该优化模型对阻尼孔的3个优化变量进行了组合优化，并将优化前后的数据输入到多孔式液压缓冲器的AMESim仿真模型中进行验证。仿真结果表明：同最初方案相比，组合优化后的液压缓冲器的内腔最高压力降低了12%，缓冲行程缩短了6.7%，缓冲过程更加平缓。     

推土机变速调压阀的控制特性

液力式推土机其变速调压阀压力控制特性决定了操作舒适性,某机型推土机存在操作时冲击大的问题,通过SimulationX对该推土机变速调压阀进行仿真分析,获得了调压阀的动态响应特性并改善了推土机的控制性能。     

推土机变速液压系统故障的分析与排除

一台ＴＹ２２０型推土机在使用中，突然瘫在地上不能动。推土机挂上前进、后退各挡位后均无反应。检查推土机的发动机，一切正常；由于推土机的前进、后退及变速均采用液压控制，因而初步判断是液压系统出现了故障。 １．液力变矩器９（见附图）输入的压力油不正常（压力不足或无油） 可能有以下４种情况：(１）调压阀６中的压力阀调压失灵由于调压阀中的压力阀调压失灵，造成液压泵１输出的液压油达不到规定值，使调压阀中的二位阀由于推动阀芯左移的控制油液压力不足而不能左移，在弹簧力作用下以左位接入系统。调压阀中的压力阀出口接油…     

操纵阀上安全调压阀的调整方法

１９８４年厦工产的ＺＬ４０、５０装载机上采用的ＤＦ３２－１型操纵阀的安全调压阀（见图１）由调压螺钉１、调整弹簧３、提动阀５、提动阀座６、弹簧１０、滑阀７、锥阀８和阀套９等组成，滑阀７上的中心小孔为阻尼孔。 装配前，应注意检查提动阀５和锥阀８的接触面密封情况、弹簧３与１０的性能以及阻尼小孔是否通畅。 调整方法 数据法 先将压力表装在操纵阀上（见图２），启动发动机后逐渐拧紧（正转）调压螺钉１（见图１），同时提升铲斗，直至铲斗向上翻转，此时暂停调整调压螺钉１；当铲斗达到极限位置时，检查压力表读数与额定压力…     

液膜阻尼技术在精磨孔中的实验研究

对精磨孔采用液膜阻尼技术后，通过对一系列不同关径间隙和不同宽度的阻尼器进行静态和动态实验，获得了精磨孔时对主轴具有最佳减振效果的阻尼器结构尺寸。     

无压力超调溢流阀的压力特性研究

该文研究了一种新型溢流阀,能有效地消除动态响应的压力超调,提高液压系统的性能。对溢流阀的压力特性进行研究,利用AMESim仿真分析了多种结构参数对压力动态特性的影响。结果表明:主阻尼孔和先导阀阻尼孔的直径大小对溢流阀的压力动态性影响很大,当主阻尼孔直径为0.8 mm、先导阀阻尼孔直径为0.7 mm时,溢流阀动态特性和静态性能都较好。阀座孔直径、调压弹簧刚度和阀芯倒角对溢流阀稳定性影响不大,但是分别对静态调压偏差和响应时间影响较大。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.