汽车防冻液知识大盘点

在众多的汽车养护用品当中,防冻液最为广大读者所熟知,但是同时它也最易被误解和错用。在一个月前的AutomechanikaShanghai 2013展会上,编辑曾在汽车用品展馆参观和了解到多种知名品牌的防冻液产品,尽管它们的品名、颜色、包装、宣传点等不尽相同,但是防冻液的主要功能大体还是一致的。有的品牌针对当今环境严重污染研发了绿色环保型产品,可谓新意与实际的完美贴合。时下正值寒冷冬季,北方多数城市和地区温度较低,汽车水箱容易因为结冰而胀裂,而汽车防冻液的选择,是事关汽车"心脏"健康的头等大事。那么,维修企业的技师们对汽车防冻液的认知是否全面?在选择使用汽车防冻液时,应该注意哪些问题呢?本文对汽车防冻液的相关知识做了梳理,希望能对广大读者正确认识和使用汽车防冻液有所帮助。     

谈谈乙二醇——水型防冻液的配置与使用

随着我国汽车工业的日益发展，为提高使用效果，减轻司机的劳动强度，防冻液已为寒冷地区广泛采用，特别是乙二醇水型防冻液。     

冬季汽车养护常识

冬季对汽车的润滑要求较高,如果使用的是夏季机油是必须更换的,对使用时间较长,颜色发黑,附着力变差的机油都应换掉,以保证发动机启动的顺畅。而防冻液的量一定要合适,不同地区和不同车型应注意防冻液的冰点度及型号,使用二年以上的防冻液应予更换,混合防冻液一年必须更换。这里要     

车辆冬季保养要点

（1）机油：冬季对汽车的润滑要求较高，对使用时间较长、颜色发黑、附着力变差的机油都应及时更换，以保证发动机启动顺畅。（2）防冻液：量一定要合适．不同地区和不同车型应注意防冻液的冰点度及型号．使用两年以上的防冻液应更换．混合防冻液一年必须更换。     

汽车防冻液的基本功能与使用注意事项

汽车防冻液的基本功能 防冻功能。各种防冻液的冰点不同，选用时，应根据地区特点、环境温度来选定。防冻液的冰点一般为-15℃--68℃。 防腐蚀功能。发动机冷却系统一般含有5种金属，即铸铁、铝合金、钢、铜及水箱焊接时用的焊锡。     

汽车防冻液选用须慎重

开车的朋友对于防冻液并不陌生,"防冻液"即发动机冷却液,是汽车发动机正常运转不可缺少的散热介质.防冻液的主要功能是:在寒冷冬季停车时,防止冷却液结冰而胀裂散热器和冻坏发动机气缸体或缸盖;而在夏季温度较高时,则能有效防沸,避免出现"开锅"现象.汽车防冻液作用大,直接影响汽车的性能和使用寿命.     

汽车防冻液选用须慎重

开车的朋友对于防冻液并不陌生，“防冻液”即发动机冷却液，是汽车发动机正常运转不可缺少的散热介质。防冻液的主要功能是：在寒冷冬季停车时，防止冷却液结冰而胀裂散热器和冻坏发动机气缸体或缸盖；而在夏季温度较高时，则能有效防沸，避免出现“开锅”现象。汽车防冻液作用大，直接影响汽车的性能和使用寿命。     

正确使用防冻液

冬季已经来临,为防止汽车的冷却系结冰而冻坏汽车缸体及其它部件,汽车开始使用防冻液。但由于缺乏有关防冻液的使用知识,许多司机都认为防冻液加的越浓越好,甚至有些司机为他的汽车加入100%纯防冻液,认为只有这样,防冻效果才可靠。事实上,这种观点是片面的。目前我国市场上销     

谈防冻液的使用

汽车要安全过冬，当然离不了防冻液．由于防冻液里有特殊成分，它冰点低，可防止汽车冷却系结冰。冬季使用防冻液．应注意啥?     

帮您选择防冻液

严寒的冬季已经来临,广大驾驶员都会选用防冻液来作为自己汽车的冷却液,但是如果选用或使用不当,就会给汽车造成不必要的故障,因此驾驶员在选用防冻液时一定要慎重,切勿贪图便宜选用不合格的防冻液,否则在使用时,就会引起不良后果.     

MK20型圆ABS的排气加液

MK20型ABS中，由于液压回路中增加了用来调节车轮制动器压力的电磁阀，使得系统的排气加液跟传统的制动系统有所不同。介绍了ABS的真空排气加液过程和ABS常闭阀控制过程，并对真空加液的操作时间节拍进行估算。试验结果表明，其排气加液效果较好。     

Impact of Dynamic Fluid Slosh Loads on the Directional Response of Tank Vehicles

SUMMARY

A comprehensive directional dynamics model of a tractor-tank trailer is developed by integrating a non-linear dynamic fluid slosh model to the three-dimensional vehicle dynamics model. The nonlinear fluid slosh equations are solved in an Eulerian mesh to determine dynamic fluid slosh loads caused by the dynamic motion of the vehicle. The dynamic fluid slosh forces and moments are coupled with the vehicle dynamics model to study the directional response characteristics of tank vehicles. The directional response characteristics of partially filled tank vehicles employing dynamic slosh model are compared to those employing quasi-dynamic vehicle model, for steady as well as transient directional maneuvers. Simulation results reveal that during a steady steer maneuver, the dynamic fluid slosh loads introduce oscillatory directional response about a steady-state value calculated from the quasi-dynamic vehicle model. The directional response characteristics obtained using the quasi-dynamic and dynamic fluid slosh models during transient steer inputs show good correlation. Based on this study, it can be concluded that the quasi-dynamic model can predict the directional response characteristics of tank vehicles quite close to that evaluated using the comprehensive fluid slosh model.     

On the Design and Development of a Magneto-Rheological Mount

This paper evaluates the performance of a Magneto-Rheological (MR) mount. The mount incorporates MR fluid in a conventional fluid mount to open and close an inertia track between the fluid chambers of the mount. It is shown that such switching of the inertia track improves the mount's isolation effect by eliminating the large transmissibility peak that commonly exists at frequencies larger than the notch frequency for conventional fluid mounts. The switching frequencies of the MR mount are evaluated based on the parameters of the mount. A simple control scheme for switching the mount between the open and closed states is proposed, and the performance of the controlled mount is compared with conventional mounts. A sensitivity analysis is conducted to evaluate the effect of parameter errors in estimating the switching frequencies and mount performance. The results show that the switching frequencies can be accurately determined from mount parameters that are easily measured or estimated.     

On the Design and Development of a Magneto-Rheological Mount

This paper evaluates the performance of a Magneto-Rheological (MR) mount. The mount incorporates MR fluid in a conventional fluid mount to open and close an inertia track between the fluid chambers of the mount. It is shown that such switching of the inertia track improves the mount's isolation effect by eliminating the large transmissibility peak that commonly exists at frequencies larger than the notch frequency for conventional fluid mounts. The switching frequencies of the MR mount are evaluated based on the parameters of the mount. A simple control scheme for switching the mount between the open and closed states is proposed, and the performance of the controlled mount is compared with conventional mounts. A sensitivity analysis is conducted to evaluate the effect of parameter errors in estimating the switching frequencies and mount performance. The results show that the switching frequencies can be accurately determined from mount parameters that are easily measured or estimated.     

Three-dimensional analysis of transient slosh within a partly-filled tank equipped with baffles

The directional dynamic analyses of partly-filled tank vehicles have been limited to quasi-static fluid motion due to computational complexities associated with dynamic fluid slosh analyses. The dynamic fluid slosh causes significantly higher magnitudes of slosh forces and moments in the transient state that cannot be characterized through quasi-static approach, which provides reasonably good estimates of the mean responses. In this study, a three-dimensional nonlinear model of a partly-filled cylindrical tank with and without baffles is developed to investigate the significance of resulting destabilizing forces and moments caused by the transient fluid slosh, and the effects of baffles. The baffles and the end caps are modeled with curved shapes. The analyses are performed under varying magnitudes of steady lateral, longitudinal and combinations of lateral and longitudinal accelerations of the tank, and two different fill volumes using the FLUENT software. The results of the study are presented in terms of mean and peak slosh forces and moments, and variations in the mass moments of inertia of the fluid cargo within a clean bore and a baffled tank, for two different fill volumes and different magnitudes of acceleration excitations. The ratios of transient responses to the mean responses, termed as amplification factors, are further described to emphasize the significance of dynamic fluid slosh on the forces and moments induced on the vehicle. The results in general suggest that the mean responses attained from dynamic fluid slosh analyses correlate well with those attained from the quasi-static analyses for a clean bore tank. The amplification ratios of the resulting forces and moments could approach as high as 2. The results clearly show that the presence of baffles helps to suppress the peak as well as mean slosh forces and moments significantly.     

Three-dimensional analysis of transient slosh within a partly-filled tank equipped with baffles

The directional dynamic analyses of partly-filled tank vehicles have been limited to quasi-static fluid motion due to computational complexities associated with dynamic fluid slosh analyses. The dynamic fluid slosh causes significantly higher magnitudes of slosh forces and moments in the transient state that cannot be characterized through quasi-static approach, which provides reasonably good estimates of the mean responses. In this study, a three-dimensional nonlinear model of a partly-filled cylindrical tank with and without baffles is developed to investigate the significance of resulting destabilizing forces and moments caused by the transient fluid slosh, and the effects of baffles. The baffles and the end caps are modeled with curved shapes. The analyses are performed under varying magnitudes of steady lateral, longitudinal and combinations of lateral and longitudinal accelerations of the tank, and two different fill volumes using the FLUENT software. The results of the study are presented in terms of mean and peak slosh forces and moments, and variations in the mass moments of inertia of the fluid cargo within a clean bore and a baffled tank, for two different fill volumes and different magnitudes of acceleration excitations. The ratios of transient responses to the mean responses, termed as amplification factors, are further described to emphasize the significance of dynamic fluid slosh on the forces and moments induced on the vehicle. The results in general suggest that the mean responses attained from dynamic fluid slosh analyses correlate well with those attained from the quasi-static analyses for a clean bore tank. The amplification ratios of the resulting forces and moments could approach as high as 2. The results clearly show that the presence of baffles helps to suppress the peak as well as mean slosh forces and moments significantly.     

地铁隧道考虑流固耦合影响的微裂隙岩体注浆数值模拟研究

为研究浆液与岩体的耦合作用机制,采用有限元方法对微裂隙岩体开展单一裂隙注浆数值计算。将连续性方程作为浆液流动的控制方程,将修改后的达西定律用于描述浆液在裂隙中的运动过程。基于弹性力学理论,提出考虑流固耦合效应的微裂隙岩体注浆扩散过程计算方法,研究裂隙开度、岩体弹性模量对注浆扩散距离的影响。研究结果表明： 1）在注浆过程中,裂隙开度由注浆孔附近向浆液扩散锋面处衰减,考虑流固耦合效应时注浆压力的计算误差能够减小30%左右,注浆扩散半径的计算误差可减小15%左右; 2）在注浆设计中应充分考虑流固耦合效应对注浆扩散过程的影响。     

应用于汽车减振的磁流变液阻尼器的设计原理

应用智能材料磁流变液（MR）构造出的半主动悬架减振系统，可以用于对车辆振动的控制。MR流体具有的独特性质在于：在强磁场的作用下，可由牛顿流体变为粘塑流体，而变液阻尼器则具有结构简单、体积小、工作连续可逆，能耗小等优点。本文介绍了磁流变液的材料特性，建立了磁流变液阻尼器的阻尼力数学模型，并提出设计变阻尼器时参数的选取原则。     

柴油机燃油喷射系统流体动力学研究进展

针对柴油机燃油喷射系统的流体动力学问题,从影响模拟精度的角度出发,分别对燃油黏性、空化、燃油的变物性和流体-结构耦合等方面进行了综述,旨在为今后更加深入的研究提供参考。概述了柴油机燃油喷射系统流体动力学研究的发展现状,提出了未来发展的方向:开展高压油泵柱塞腔、喷油器控制腔和蓄压腔等腔体内燃油的高维流体动力学分析;考虑流体内部及流体-结构耦合传热引起的温度场变化;考虑燃油物性随温度和压力的变化及变化率;对喷射系统建立流-固-热强耦合瞬态分析模型,分析水击压力、管道振动及泄漏问题;继续进行燃油的高温高压特性测试。