Analysis of Oil Consumption in Cylinder of Diesel Engine for Optimization of Piston Rings

The performance and particulate emission of a diesel engine are affected by the consumption of lubricating oil. Most studies on oil consumption mechanism of the cylinder have been done by using the experimental method, however they are very costly. Therefore, it is very necessary to study oil consumption mechanism of the cylinder and obtain the accurate results by the calculation method. Firstly, four main modes of lubricating oil consumption in cylinder are analyzed and then the oil consumption rate under common working conditions are calculated for the four modes based on an engine. Then, the factors that affect the lubricating oil consumption such as working conditions, the second ring closed gap, the elastic force of the piston rings are also investigated for the four modes. The calculation results show that most of the lubricating oil is consumed by evaporation on the liner surface. Besides, there are three other findings： （1） The oil evaporation from the liner is determined by the working condition of an engine; （2） The increase of the ring closed gap reduces the oil blow through the top ring end gap but increases blow-by; （3） With the increase of the elastic force of the ring, both the left oil film thickness and the oil throw-off at the top ring decrease. The oil scraping of the piston top edge is consequently reduced while the friction loss between the rings and the liner increases. A neural network prediction model of the lubricating oil consumption in cylinder is established based on the BP neural network theory, and then the model is trained and validated. The main piston rings parameters which affect the oil consumption are optimized by using the BP neural network prediction model and the prediction accuracy of this BP neural network is within 8%, which is acceptable for normal engineering applications. The oil consumption is also measured experimentally. The relative errors of the calculated and experimental values are less than 10%, verifying the validity of the simulation results. Applying the established simulation model and the validated BP network model is able to generate numerical results with sufficient accuracy, which significantly reduces experimental work and provides guidance for the optimal design of the piston rings diesel engines.

Experimental Study on Wear Performance and Oil Film Characteristics of Surface Textured Cylinder Liner in Marine Diesel Engine

It is of a vital importance to reduce the frictional losses in marine diesel engines. Advanced surface textures have provided an e ective solution to friction performance of rubbing pairs due to the rapid development of surface engineering techniques. However,the mechanisms through which textured patterns and texturing methods prove beneficial remains unclear. To address this issue,the tribological system of the cylinder liner?piston ring(CLPR) is investigated in this work. Two types of surface textures(Micro concave,Micro V?groove) are processed on the cylinder specimen using di erent processing methods. Comparative study on the friction coe cients,worn surface texture features and oil film characteristics are performed. The results demonstrate that the processing method of surface texture a ect the performance of the CLPR pairs under the specific testing conditions. In addition the micro V?groove processed by CNCPM is more favorable for improving the wear performances at the low load,while the micro?con?cave processed by CE is more favorable for improving the wear performances at the high load. These findings are in helping to understand the e ect of surface texture on wear performance of CLPR.

Study on Oil Film Model of Electronic Fuel Injection Motorcycle Engine Cylinder

Based on the principles of heat transfer,an oil film model in the engine cylinder was established.Under the condition of cold state,the influence of factors such as engine fuel injection,fuel drop point,cylinder inner wall temperature,and inlet fluid on the oil film is comprehensively considered to establish an oil film quality prediction model.Based on the measurement of the compensation oil quantity in the transition conditions,the variation of the oil film during the transition is analyzed.The experimental results show that the velocity of the air-flow in the intake port and the temperature and pressure on the wall of the intake port are the main factors affecting the oil film in the cylinder.Based on the abovementioned experimental and theoretical studies,an oil film distribution model for each cycle of the transition condition was established based on the engine inlet oil film model.The experimental measurement curve and model prediction curve for the fuel compensation per cycle in the transition condition from 10%load to 30%load.The model established can be in good agreement with the experimental results and meet the fuel compensation trend in the transition condition.While realizing the fuel compensation for the transient conditions,this work is definitely helpful to achieve accurate control of the air-fuel ratio.

Proposal of a Component to Restrict Dust from Entering an Oil Hydraulic System through an Oil Hydraulic Cylinder

This research proposes a component to restrict dust from entering an oil hydraulic system through the rod-seal clearance of an oil hydraulic cylinder.The oil hydraulic cylinder as one of main parts of the hydraulic system,controls position of load by reciprocation.For example,on construction machines such as excavators and graders,the cylinder controls position of folk lift,crane and bucket.However,during operation,dust enters the cylinder,wears seals,causes fluid degradation and affects lubrication of valves,pumps and other parts of hydraulic system.This increases breakdown rate of cylinder and entire system.Thus,it seems necessary to reduce on intrusion of dust into the system via the hydraulic cylinder.In this research,we made an experimental apparatus to simulate intrusion of the dust into system.Results proved that the apparatus is a suitable simulator to realize the intrusion.The proposed component to restrict dust from entering cylinder was fabricated and its performance tested when inserted with various elastic rings.The component gave tremendous results when inserted with O-ring seal and a plastic nylon washer,and can be retrofitted on new and old hydraulic cylinders.It is an appropriate technology especially in developing countries where dust is still a major concern.

Study on Oil Cavity Number of Hydrostatic Guide Sleeve of Electro-hydraulic Servo Cylinder

The electro-hydraulic servo drive hydraulic cylinder has many unique advantages, such as fast response, high load stiffness, high control power, strong anti-eccentric load ability and so on, so it has been widely used in industrial control. Based on the guide sleeve of hydrostatic seal of hydraulic cylinder, the reasonable number of oil chamber of guide sleeve is studied in this paper. ICEM CFD software and FLUENT simulation software are used to calculate and analyze the number of different oil chambers of guide sleeve of hydrostatic seal. The temperature field of piston rod with different moving speed, different initial pressure of oil chamber and oil film under different number of oil chambers is analyzed. The relationship between the pressure field and temperature field provides a better basis for optimizing the design of hydrostatic guide sleeve and helps to improve the servo drive cylinder.

Analysis on Static Pressure Bearing Seal Characteristics of Guide Sleeve of Electro-hydraulic Servo Cylinder

As a typical bionic walking robot, hydraulic quadruped robot has attracted much attention because of its high mobility, strong load capacity and steady motion. The electro-hydraulic servo cylinder, as its power actuator, requires low friction, good lateral load resistance and high speed motion. The electro-hydraulic servo cylinder hydrostatic bearing seal guide sleeve is taken as the research object in this paper. By using Fluent software to analyze and contrast the film characteristics of rectangular and I-shaped oil chamber of hydrostatic bearing seal guide sleeve, the relationship between piston rod moving speed, eccentricity, oil film carrying capacity, friction force and leakage volume, as well as the relationship between oil feed flow and oil film bearing capacity, friction force, inlet pressure and leakage volume were analyzed. This study provides a theoretical basis for optimizing the static pressure bearing seal parameters.

低硫条件下船舶主机缸套-活塞环磨损现状与应对策略

国际海事组织(IMO)的“限硫令”于2020年1月在全球范围内实施后,燃用低硫燃油(LSFO)成为许多远洋公司的主要选择。对多家远洋公司船舶主机燃用LSFO后的运行状况进行调研,发现缸套、活塞环等零部件存在异常磨损及故障显著增多的现象。将LSFO对船舶主机的影响以及其实际应用案例进行分析与总结,并针对燃用LSFO的主机所出现的异常磨损和故障现象提出应对策略。该研究有助于解决LSFO条件下船舶主机缸套和活塞环异常磨损问题的实际需求,希望进一步推动LSFO条件下缸套和活塞环异常磨损的机理研究。

碎纸机收纳桶塑件的注塑模具设计

根据碎纸机收纳桶产品的外形特征与成型要求,设计了一副包括定模隧道滑块油缸抽芯机构、推板带斜顶抽芯机构、斜顶内带司筒和弹针顶出结构的复杂注塑模具。其中,推板带斜顶抽芯机构用于脱出塑件内观面上的两个倒扣,斜顶内带司筒和弹针顶出结构成功解决塑件内部的4个柱子倒扣的脱模问题,设置的定模隧道滑块油缸抽芯机构用于脱出塑件外观面上的倒扣。推板带动斜顶抽芯的同时完成塑件的顶出,在模具结构上省去了顶针板结构。模具在制作调试过程中,各项顶出抽芯机构无干涉,针对塑件成型时易出现的问题,通过进一步的模具结构优化设计加以解决。在模具投入使用后,已生产塑件产品达3万件,塑件尺寸精度及外观质量要求符合预期。

双作用的液压油缸自动测试台

根据油缸生产要求,设计了一种双作用的液压油缸自动测试台。该测试台基于设计的液压原理图,采用LabVIEW软件,实现对单作用油缸和双作用油缸的全自动测试,包括试运转测试、耐压测试、内泄露测试,从而满足企业生产需求。

带式输送机用双油缸液压张紧装置设计

【目的】液压张紧装置是可伸缩带式输送机的关键组成部分,对于确保输送机在启动、行驶和制动等过程中的稳定运行具有重要的意义,但传统液压张紧装置的设计会有张紧力调整不方便、张紧装置结构复杂的缺点,有必要对此进行研究。【方法】设计一种适用于带式输送机的双油缸液压张紧的装置,其兼具螺杆张紧装置与液压张紧装置的优点。【结果】该装置具有工作状态平稳、响应速度迅速、空间需求较小、性能出众等优势,其双油缸设计还能够大幅度降低输送带发生跑偏情况的概率。【结论】该装置主要用于短距离带式输送机,不仅延长了带式输送机的使用寿命,而且大大提高了工作的安全系数。

柴油机活塞环润滑油膜厚度超声波测量方法研究

活塞组件-缸套摩擦副位置处良好润滑状态能够保障柴油机的稳定运行,润滑油膜厚度能够对其润滑状态进行判断。因此本文以润滑油膜厚度为测量目标,基于等效弹簧模型超声波测量原理对活塞环位置处润滑油膜厚度开展实验研究。搭建了润滑油膜厚度超声测量实验平台,通过实验证实了超声方法的测量能力。构建了柴油机活塞环润滑油膜厚度测量方案,设计并搭建了活塞环润滑油膜厚度动态测量系统,对不同转速下的润滑油膜厚度进行了实验测量。通过对实验数据进行处理,在活塞环处测得了2.2~3.9μm的润滑油膜厚度,并且随转速增加,油膜厚度呈现增大趋势,证实了该方法的可行性。

煤矿环境下激光熔覆层失效分析

针对煤矿环境下油缸激光熔覆层腐蚀失效问题,分析井下用水、煤粉浸泡液水、煤质等矿井环境,用金相显微镜研究熔覆层的微观组织,使用SEM图像、EDS能谱、XPS等手段研究熔覆层腐蚀状态及化学元素,探讨了熔覆层在煤矿环境下的腐蚀机理。结果显示,熔覆层和基体冶金结合良好,内部未发现缺陷;组织呈树枝状结晶和椭圆、颗粒形状分布,越靠近基体,枝晶越细小;腐蚀坑深度50~150μm,可达熔覆层厚度的1/4,大小深浅不一;熔覆层化学成分均匀,元素含量满足设计要求,不存在明显的元素偏析;EDS能谱、XPS等测试结果显示腐蚀从熔覆层枝晶间的贫铬区开始,S、Cl等元素参与了腐蚀过程;含有S、Cl等腐蚀介质的煤粉与熔覆层间的点蚀、接触腐蚀等导致熔覆层失效。研究为煤矿环境下油缸的表面处理工艺设计提供了参考。

内燃机油环对活塞-缸套间流动与润滑油输送的控制

以某四冲程内燃机为研究对象展开研究,根据其油环和活塞结构特性、缸套表面润滑油分布建立油环流量平衡和力平衡方程。通过分析运行时润滑油的输送过程,以及油环上方环岸区域润滑油量的变化及其沿缸套自下而上的输送过程,得出如下结果:油环控制油环-缸套间润滑油的流动,使环岸区域在活塞向下行程时储存润滑油,并在活塞向上行程时将润滑油输送至活塞上止点,实现润滑油的输送,满足活塞在上止点的润滑要求。

特种缓冲油缸温度适应性研究

在进行水中兵器减振降噪的研究过程中,发现作为其重要传动部件的特种缓冲油缸是主要噪声源之一,因此特种缓冲油缸的缓冲装置设计尤为重要,而对缓冲效果的预测是缓冲设计的核心问题。由于特种缓冲油缸工作情况的特殊性,其大多数时间都处于待机状态,当间隔很长时间后启动时,缓冲腔内的液压油温度等于所处安装环境温度,一次启动和后续启动之间缓冲腔内的液压油会有较大的温差。为了保证在极端温度条件下也能满足工作要求,需对特种缓冲油缸进行温度适应性研究。文中首先建立了特种油缸运动过程的数学模型,在油液极端温度10±2℃、40±2℃,供油压力7.5±0.2 MPa条件下,利用Fluent软件进行了流场数值仿真。然后在大型温度箱中进行了温度适应性试验,分别检测了2个极端温度条件下特种缓冲油缸的全行程运动时间和振动加速度级等参数。经对比发现,试验结果与理论分析相近,符合相应指标要求,可为特种缓冲油缸的设计和减振降噪提供参考。

吴江卷曲式人行开启桥设计

吴江卷曲式人行开启桥项目位于吴江区东部两省一市交界区域,是规划水乡市集节点水上活动中心游艇进出元荡湖的主要出口,对景观要求高,要求修建一座标志性建筑的景观人行桥,该桥同时有开启要求,综合考虑多种因素,最终采用卷曲式人行开启桥方案。介绍了该卷曲式开启桥的特殊地理位置、方案构思、通航条件、总体设计、结构设计、液压设计、开启顺序等。通过研究,该工程达到了预期的景观和开启性能目标,具体分析方法和结论可供同类工程参考。

液压支架千斤类缸筒中心架找正工装的设计与应用

液压油缸作为液压支架的动力执行元器件,主要完成支架的推溜拉架及其他辅助性的动作,因此需要液压油缸具有高可靠性,保证在工作状态时不漏液、渗液。千斤类缸筒现有加工工艺是在加工过程中需要在缸筒外圆加工中心架架窝,以此来转换基准,保证缸筒内壁同轴度要求,为此设计了一种液压支架千斤类缸筒中心架找正工装。实践表明,使用该工装加工中心架架窝,可有效避免因架窝精度差造成缸筒内壁同轴度无法保证的问题,提升了产品质量,改变了现有加工工艺,实现效益和效率双重提升。

油缸活塞导向套的表面质量提升方法研究

本文探讨了提升导向套表面质量的必要性、面临的挑战以及相应的策略。通过对表面粗糙度需求和实际之间存在的差距,材料选择和表面处理技术所面临的挑战,环境因素影响及生产过程质量控制困难等方面进行了分析,提出采用先进的加工设备,选用适当的表面涂层或者润滑方式,采取防护措施,并进行严格的质量控制与检验等策略。这些措施都是为了保证导向套表面质量处于最佳状态,以延长装置使用寿命和改善其性能。

拖车钻立塔油缸同步问题的探讨

拖车钻立塔油缸的同步关系到拖车钻设备在施工中的稳定性、安全性和使用寿命,在生产制造过程中需要通过一些方法使钻塔的立塔与落塔稳定、可靠,以核昌公司生产的HXY-800QT拖车钻为研究对象,介绍了液压缸不同步的原因及在生产制造过程中的经验总结和装配注意事项,为今后拖车钻在地质勘探行业的发展提供一些借鉴。

油缸内孔刮滚加工刀具的优化

刮滚加工是油缸内孔精加工常用的一种方法,通过一次装卡,完成内孔粗镗、刮削、滚压3道工序,粗镗头包含位于同一圆周面上的4个镗刀片,用于切除缸筒内孔的大部分余量。现用TGK53刮滚机粗镗时刀片切削刃有效切削长度较短,刀片易受热损坏、寿命较低;刀片主偏角75°,向前镗孔时径向分力较大,造成刀具或缸筒震动,加工质量无法保证。通过选择高寿命刀片、调整切削角度、优化刀夹结构、改善切削参数,提高刀具寿命、加工效率以及产品尺寸精度。

升船机钢丝绳-缓冲油缸防撞装置设计方法

钢丝绳-缓冲油缸防撞装置主要应用于过船规模较大的升船机工程中,目前关于该形式防撞装置设计方法的研究甚少,且存在一定局限性,直接影响防撞装置的布置和设计。基于船舶与防撞装置撞击过程中能量转换以及空间几何关系的分析,提出钢丝绳-缓冲油缸防撞装置设计计算方法,包括钢丝绳张力、船舶水平行进距离和油缸缓冲行程等重要参数的设计计算和控制条件的确定。通过设计计算结果与向家坝升船机钢丝绳-缓冲油缸防撞装置实船试验结果的比较,验证了本设计方法的安全性和合理性。提出的设计方法可为升船机钢丝绳-缓冲油缸防撞装置的设计和改造提供参考。