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应用KULI和STAR-CCM+软件对客车发动机冷却系统进行仿真分析,计算得到发动机的进出水温度和中冷器的进出气温度,与发动机热平衡试验的结果进行对比分析,验证了该仿真分析方法的准确性和可行性,为发动机舱冷却系统的设计和零部件布置提供依据。 相似文献
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随着非道路移动工程机械发动机机功率的不断增加,为满足柴油机的动力性和经济性指标,对增压空的气冷却提出了越来越高的设计要求。本文通过场地试验的方法对比研究了水冷中冷器与空冷中冷器对某款装载机柴油机工作特性的影响。试验结果表明,水冷中冷器相比于传统的风冷中冷器能更有效的降低柴油发动机的进气温度:水冷中冷器在铲装作业和高速跑工况下增压空气平均出温分别比空冷中冷器低27.6%和10.5%,柴油机扭矩提升为1.6%和6.3%,并且油耗降低了4.0%和2.5%。相对进气压力对柴油机经济性指标有一定影响,适当增加进气压力可以减少油耗。 相似文献
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介绍了柴油引燃甲醇双燃料燃烧对柴油机动力性和经济性的影响。在1台单缸、直喷、中冷柴油机上采用柴油引燃甲醇双燃料进行试验。结果显示甲醇柴油双燃料发动机在中高负荷及中高转速下运转可获得较好的燃油经济性。选择适当的引燃柴油量,双燃料发动机的动力性可以达到甚至超过原柴油的动力性。 相似文献
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热气机冷却器是斯特林外燃机系统的重要组件之一,围绕冷却器所开展的研究也一直是斯特林热气机研究的重点之一。开发热气机冷却器设计,该热气机为四缸结构、斜盘式传动、氦气工质、淡水闭式强制冷却,其热能取自太阳能。为验证所设计的冷却器的特性,配备了性能测试试验台。实验结果表明,冷却器的设计思想及步骤是行之有效的,设计结果达到了预期技术指标。 相似文献
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Diesel emission regulations have recently become more severe. An important goal in diesel engine research is the development of methods to reduce the emissions of NOx and PM (particulate matter). Cooled EGR (exhaust gas recirculation) system has been widely used to reduce the NOx and PM emissions of light-duty diesel engines. In this study, numerical analyses, rig tests and engine tests were performed to assess how changes in internal shape characteristics can improve the heat exchange efficiencies of EGR coolers. The heat exchange efficiencies of EGR coolers have been numerically and experimentally measured during a fouling process. The results show that the second type of oval EGR cooler tested (oval #2) exhibited better heat exchange efficiency than either the first type of oval EGR cooler was tested (oval #1) or the shell and tube cooler examined. The turbulence generated in exhaust gas flows by the wavy-finned design of the oval EGR coolers facilitated PM desorption that allows these coolers to self-purify. With respect to the two similar oval EGR coolers, the cooler with fin pitch 4 mm has better efficiency than the cooler with fin pitch 6 mm due to differences in the heat transfer areas of these coolers. Both CFD analyses involving extreme conditions of engine operation and engine fouling tests involving conditions experienced during vehicular operation indicate that the two oval coolers differed by less than 4% with respect to both initial heat transfer efficiency and heat transfer efficiency after a 78-hour fouling test. 相似文献
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天然气发动机电控系统仿真研究 总被引:1,自引:0,他引:1
利用计算机仿真技术在电控喷射发动机上的应用,可以更好地提高燃气机乃至汽车的整体性能.该研究建立的天然气发动机模型是一个连续时间域的、平均值发动机模型(MVEM),根据采集的发动机台架试验数据,采用调节天然气发动机平均值模型内部的PID参数的方法来匹配试验数据与模拟仿真结果.计算机仿真获得的数据具有很好的精度,仿真模型获得的发动机工况点可以指导电控系统与燃气机的匹配. 相似文献
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发动机试验,是用科学的试验方法揭示发动机内部的变化规律,找出提高其动力性、经济性、可靠性等各种性能的途径.从准备阶段到试验,再到试验后的数据处理,都存在着影响发动机试验数据准确性的因素:发动机的技术状态、安装位置、机油的添加量等会影响发动机的性能;试验人员的技术水平,测试仪器、试验方法的选择等会影响测试结果;试验条件的控制,测试数据的处理方法等也会影响测试结果.通过对试验全过程的分析可知,影响数据准确性的因素主要可分为样品、检测人员、测试仪器、试验方法及数据处理,试验环境和设施条件等几个方面. 相似文献
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发动机的热试为发动机制造过程中的一项重要环节,主要对发动机的性能、排放、可靠性及耐久性等方面进行测试。描述了热试台架的组成及其实际应用,从台架构造、测试系统、电气控制系统及公用系统等方面论述了一个高效、环保及低成本的热试系统。通过实际生产应用,说明了该热试系统在小排量发动机测试方面的实用性及经济性等。 相似文献
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汽油机油配方对节能发动机试验的影响 总被引:1,自引:1,他引:1
介绍了汽油机油节能发动机试验的发展状况,讨论了油品配方对节能性能的影响。发动机试验表明,基础油、粘度指数改进剂及添加剂都是影响汽油机油节能性能的因素,在不同的发动机试验中基础油、粘度指数改进剂、抗氧抗腐剂、摩擦改性剂、清净剂、分散剂的影响存在不同的表现形式,在配方设计中要根据具体的发动机试验来确定。 相似文献
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An advanced liquid lubricant for heat engines has been developed and tested successfully in a prototype engine. The lubricant possesses superior oxidation stability and high temperature stability. With the advent of new engine designs, stability should be measured in terms of both the temperature and the time for which the lubricant is subjected to it. This lubricant is designed to provide friction and wear protection for three to five minutes at 425°C (800°F) at the ring zone and maintains stability at an oil sump temperature of 171°C. The lubricant has been evaluated by the Cummins Engine Company. Out of a field of several dozen lubricants, six lubricants were selected for a prototype 200 h endurance tests. The NIST lubricant was one of the two lubricants that successfully finished the endurance testing. This paper provides an overview of the key lubricant design considerations, including oxidation and thermal stability, volatility, and deposit control, the prototype engine test conditions and the results. 相似文献