巧辨第二道活塞环的锥面方向

众所周知,在四冲程发动机活塞环中,第二道环为锥面环。由于环的外圆为锥面形,减少了与汽缸壁滑动面的接触面积,使其接触压力得以提高,从而改善了运转初期的磨合,并在短期内能够稳定机油消耗量和减少漏气。这种锥面环在活塞上升行程中，不会损坏油膜，而是像雪橇那样在油膜上滑过如图所示，并在环的下方留下油膜（称液体润滑）。     

巧辨第二道活塞环的锥面方向

活塞环(如图1、图2所示)是在高温、高压条件下唯一做轴向运动、径向运动和旋转运动的零件,同时也是工作条件最为苛刻的零件,在发动机运行中起着非常重要的作用。从外表看,活塞环是一个具有开口的弹性环体,非常容易损坏。四冲程发动机活塞环的第一道环和第二道环被统称为压缩环,压缩环的首要作用在于防止燃烧室漏气。为了达到这个目的,气缸壁与活塞环滑动面之间有油膜,这对于提高活塞环的气密性起着非常重要的作用。     

巧辨四冲程摩托车烧机油

很多摩友对爱车出现烧机油的问题头疼不已,维修时寻找故障原因也十分麻烦,尤其是对气门、气门油封、气门导管的判断更有一定的难度。笔者是一名摩托车维修人员,有一些小经验介绍给大家。 当出现烧机油时,注意观察摩托车冷启动时有无白烟冒     

活塞环与窜油检修要点

在发动机结构中,活塞环是一个具有弹性的开口环体,也是在高温、高压环境下需做三个方向运动的唯一零件,工作条件最为苛刻,非常重要且易受损,一旦产生异常,就会出现窜机油和动力下降等故障。其检修注意要点如下:1、仔细察看第二道气环和油环下部至活塞裙部,如     

巧辨气门 活塞环漏气

气门由头部、杆部和锥面组成(如图1所示),是发动机进、排气道中的控制元件。气门的密封锥面的锥角一般做成45°,它与气门座圈45°形成密封副,共同担任气门的密封作用。在进气行程中,发动机依靠进气门的开启,可使新鲜可燃混合气进入汽缸。在排气行程中,则依靠排气门的开启,把燃烧室膨胀做功后的废气排出汽缸。气门的工作条件极其恶劣,气门头部的工作温度异常高。进气门温度在300℃～400℃之间,排气门的温度则更高达770℃～930℃,极易被烧蚀,从而产生泄漏。     

活塞环失效原因分析及预防对策

活塞环是发动机的重要组成部件,它具有密封、散热、刮油及布油的作用。由于活塞环对燃料的燃烧、可燃混合气的密封及发动机的正常工作起着至关重要的作用,所以它将直接影响发动机的动力性与经济性。活塞环失效后,发动机将出现起动困难,功率下降,曲轴箱压力升高、通风系统严重冒烟,机油消耗量增加,排气管冒蓝烟,燃烧室、活塞表面严重积碳等不良状况。     

活塞环刮片的加工与持续改进

钢带组合油环,由起刮油作用的刮片和产生径向、轴向弹力,并支撑刮片的衬簧组成。它具有良好的控油能力,比压均匀,对气缸追随能力强,广泛应用于中、高速四冲程汽油机。     

活塞环内外圆仿形加工与铸造

车用四冲程发动机的活塞环一般由二道气环和一道油环组成,活塞环的材料也基本上形成了一致的格局,为铸铁和钢质。铸铁活塞环多用在柴油机上,以及汽油机的第二道环上。在铸铁环的加工中,内外圆仿形加工与铸造是特别关键的。     

如何延长活塞环的使用寿命?

活塞环的性能与寿命跟发动机的工作性能有着直接关系,因此,延长活塞环的使用寿命显得很重要。可以从以下几个方面做起:1合理选材活塞环装在活塞的头部,工作条件十分恶劣,是在高温、高压、高速及润滑条件极差的情况下工作的,因此要求活塞环的材料应具备良好的耐热性、导热性、耐磨性,有一定的韧性、弹性和足够的强度等。目前,广泛采用的活塞环材料为优质灰铸铁、     

活塞环对口故障的诊断及成因

故障诊断方法 在发动机运转时，从排气管排出大量蓝白色的浓烟，并伴随一种“喝、喝”的声响，严重时在加机油口处倾听，还可听到较明显的“噗、噗”声响。对于汽油发动机，可采用逐缸用螺丝刀在火花塞上短路断火的方法；对于柴油发动机，可采用逐缸松开喷油器的高压油管的方法，     

活塞环密封性计算与试验的研究

本文介绍了新型复合活塞环的动态理论依据,对活塞环建立动态数值模型,模拟计算了新型复合活塞环与传统活塞环开张x值(气缸增加和减小的半径之差)并进行比较,与此同时进行基于倒拖法的动态试验研究。结果表明,动态数值模拟和基于倒拖法的实验都证明了新型复合式活塞环密封性优于传统活塞环,且低速度段最大爆发压力就提高10%以上,随着转速升高,新型复合式活塞环比传统活塞环更能表现其优越的密封性。     

Study of the simulation of piston skirt contact

In order to reduce the number of engine tests, it is very important to simulate the piston-cylinder bore contact. In this paper, the method of piston skirt-cylinder bore contact pressures have been studied by using the data of piston skirt profiles, its stiffness, and its thermal expansions. Therefore, piston skirt-cylinder bore contact pressures finely correlate with the skirt conditions after running tests.     

避免“飞车”宜选择第二条车道行驶

在交通事故即将来临时,我们选择什么样的措施来换取最小的损失呢？这恐怕是每一个新手都特别关心的问题。也许一个恰当的技术动作能保证车辆避开事故,而一个错误的动作会造成人员伤亡的重大损失。     

Tangential force variation due to the bogie direction reversal procedure

A range of tangential forces is generated within the contact patch when a wheelset moves on the rail. These forces are intensified when incorporating curved tracks and motored axle rail vehicles [Arrus, P., de Pater, A.D. and Meyers, P., 2002, The stationary motion of a one-axle vehicle along a circular curve with real rail and wheel profiles. Vehicle System Dynamics, 37(1), 29–58]. The wheelset is subject to flange contact if an unbalanced force remains in a curve towards the high rail gauge face. The resultant force in the transverse direction includes the lateral force, the radial force, and the creep forces in addition to the effect of the frequent wheelset displacement due to the kinematic oscillation [Iwnicki, S., 2003, Simulation of wheel–rail contact forces. Fatigue Fracture Engineering Material Structure, 26, 887–900]. This article has focused on a potential variation in some of the forces cited when the wheelset is subject to backward and forward movements. A severe wear rate observed within the wheel flange region in Iranian Railways was investigated by operating a test bogie on a curvaceous track. An obvious improvement in the wear rate and wear pattern of the wheels was attained when the second test bogie encountered a bogie direction reversal procedure. This enhancement is considered in this article from the force analysis standpoint.     

Tangential force variation due to the bogie direction reversal procedure

A range of tangential forces is generated within the contact patch when a wheelset moves on the rail. These forces are intensified when incorporating curved tracks and motored axle rail vehicles [Arrus, P., de Pater, A.D. and Meyers, P., 2002, The stationary motion of a one-axle vehicle along a circular curve with real rail and wheel profiles. Vehicle System Dynamics, 37(1), 29-58]. The wheelset is subject to flange contact if an unbalanced force remains in a curve towards the high rail gauge face. The resultant force in the transverse direction includes the lateral force, the radial force, and the creep forces in addition to the effect of the frequent wheelset displacement due to the kinematic oscillation [Iwnicki, S., 2003, Simulation of wheel-rail contact forces. Fatigue Fracture Engineering Material Structure, 26, 887-900]. This article has focused on a potential variation in some of the forces cited when the wheelset is subject to backward and forward movements. A severe wear rate observed within the wheel flange region in Iranian Railways was investigated by operating a test bogie on a curvaceous track. An obvious improvement in the wear rate and wear pattern of the wheels was attained when the second test bogie encountered a bogie direction reversal procedure. This enhancement is considered in this article from the force analysis standpoint.     

组合密封圈安装的快捷方法

本文针对卧式加工中心TH6940回转工作台配油轴的结构特点,结合其周边境况,经过对所选用组合密封圈材质、性能及组成进行深入了解、分析过后,设计出了一套专用工装,并制定了较为详细的安装工艺步骤,解决了此类密封圈安装难的问题,恢复了设备运转,节约了维修时间,带来了工作效益。     

Capacity estimation of torque converters with piston holes using the response surface method and an artificial neural network

In new slim torque converters, lock-up clutches are used to provide high fuel efficiency at low speed. However, the slimness of the converters causes difficulty in heat dissipation, which may damage the friction material and shorten its life span. A cooling hole in the lock-up piston reduces the heat but also reduces the torque because oil flows through the hole due to the pressure difference between the two faces of the piston. In the early stages of the development of this type of torque converter, designers must consider the minimum flow rate required to cool the friction material and the minimum torque capacity required to transmit the engine torque. This research explored two methods of estimating these parameters. In the first method, an estimation equation was derived by combining the response surface method with physical properties such as the centrifugal force, a sudden expansion, a sudden contraction, and the steady flow energy equation. The second method involved the use of an artificial neural network. The feasibility of the estimates based on statistics and on the artificial neural network were confirmed in the design stage by comparing experimental and estimated data. An estimation program was created using the C#.Net language and has been used for actual torque converter designs by the Korea Powertrain Company.     

专业化销售与多品牌经营将是汽车服务发展的方向

《汽车品牌销售管理实施办法》（以下简称《办法》）自2005年4月1日施行以来,分品牌经营和大一统整合经营成为在《办法》实施框架之下的两种汽车销售服务模式。     

水平定向钻机技术现状与可行性研究的分析

以水平定向钻机国内外发展现状为背景,介绍了水平定向钻机的工作原理及系统功能,并对其主要组成系统和装置,以及关键的技术进行了可行性研究的分析.