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近几年来,汽车发动机尤其是进口汽车发动机大修后,磨损速度明显加快,往往只行驶了几万千米,就出现窜机油、冒黑烟,气缸早期磨损严重,如何能使汽车发动机大修寿命和新发动机相近,这向我们汽车维修行业提出了新的要求。 据介绍,美国通用汽车公司为解决气缸耐磨问题,于1987年建立了缸 相似文献
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一一台东风EQ6100-I汽油发动机进厂维修。据车主反映:这台发动机是因捣缸事故半月前由某汽车修理部大修过。发动机在大修过程中更换了新缸体,其它机件也按大修技术要求进行了更换和配制。大修后除机油压力较低外其它各项技术性能都很好,就因为 相似文献
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目前不少大中型汽修企业,对汽车柴油或汽油发动机大修还缺少较为规范和有效的工艺流程,任由不同水平的修理工按自己技术水平来随便修发动机。现代汽车大修发动机是维修工艺最为复杂的、使用维修机具设备最多、耗费工时最长、维修技术标准化程度最精密的修理项目,所以就算有丰富经验和能力的修理工,也未必能按照现代汽车大修柴油或汽油发动机规范和有效 相似文献
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汽车发动机大修是以恢复其技术性能为目的的修理作业,修竣后的发动机各项技术指标是否符合原厂设计标准,是评价发动机大修质量的基本准则. 相似文献
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发动机总成无论是在大型的汽车修理厂还是在小型的个体汽车修理厂大修后,都必须进行冷磨与热试,这是完成发动机总成大修必不可少的工序之一。目前,国内一些修理厂为了纯粹地追求经济效益,不进行发动机总成大修后的冷磨与热试。这种做法是不正确的,不能达到维修后的技术要求,因此,必须要加以改进。 相似文献
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案例1一辆奥迪Q7 3.6汽车,行驶里程7.85万km。据车主反映,该车因发动机进水在其它修理厂大修了发动机,但大修后机油压力指示灯点亮,且发动机运转时噪声较大。 相似文献
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发动机是汽车行驶的动力来源,就像人的心脏,直接影响车辆性能及使用寿命;因此,养车必先养"心",而要想保持"心脏"的澎湃动力,就需要选用高性能的发动机润滑油。美孚旗下的 相似文献
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发动机作为汽车的一个重要组成部件,其稳定运行是保证汽车正常行驶的关键,因此,对发动机的故障检测也成为了汽车日常维修处理的一个重要环节,本文针对汽车发动机检修,探讨在汽车发动机故障检测中如何充分利用气门非配对研磨技术,对提高汽车发动机修理水平,确保汽车发动机故障维修质量具有非常重要的意义. 相似文献
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运用质量管理学和误差理化,对汽车发动机修理中的配气相位变化情况进行了生产调查及生产工艺分析,指出了有效地解决发动机配气相位质量问题的途径,是认真改进零件的修复工艺和严格检查配件质量。 相似文献
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柴油机缸内冷却液流动的数值模拟 总被引:1,自引:1,他引:0
利用三维CAD软件Pro/E对6缸柴油机冷却水套建立模型,然后对其进行网格划分,用CFD商用软件Fluent进行模拟计算,得到整机冷却水套内冷却液速度分布、压力损失以及各缸流量分布等信息,计算结果用于指导冷却水套结构的优化设计。 相似文献
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Numerous research has been devoted to finding a method to simultaneously reduce NOx and soot emissions from diesel engines. In-cylinder EGR stratification is a technique that simultaneously reduces NOx and soot using a nonuniform EGR distribution in the combustion chamber. To study the potential of in-cylinder EGR stratification, a new combustion model is required that considers the non-uniform EGR distribution and the chemical kinetics. In this study, a new combustion model, the Flamelet for Stratified EGR (FSE) model, was developed to consider the non-uniform in-cylinder gas distribution based on chemical kinetics. The concept of the FSE model is based on using multiple flamelets with the multizone concept. To describe the non-uniform gas distribution, the combustion chamber is divided into several zones by oxygen concentration at the start of injection. Then, the flamelet equations are solved at the boundary of each zone. The final species mass fraction of each cell is calculated using linear interpolation between two results from the boundaries. In this paper, the FSE model was validated under in-cylinder EGR stratification conditions, and then, the potential of in-cylinder EGR stratification was studied by using the FSE model. The effect of in-cylinder EGR stratification was verified under various injection timing, engine speed, and road conditions with optimized engine geometries. The results shows simultaneous NOx and soot reductions under the stratified EGR condition. 相似文献
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The oxidation of unburned hydrocarbons from piston crevices was modeled using a modified one-step reaction equation. This
new one-step oxidation model was developed by modifying the Arrhenius reaction rate coefficients of the conventional one-step
reaction equation. The predictions of the new one-step oxidation model agree well with the results of the detailed chemical
reaction mechanism in terms of the 90% oxidation time of the fuel. The effects of pressure and intermediate species in the
burnt gas on the oxidation rate were also investigated and included as additional multiplying factors in the modification
of the equation. To simulate the oxidation process of unburned hydrocarbons from a piston crevice, a two-dimensional computational
mesh, based on the conventional engine geometry, was constructed with a fine mesh density at the regions of the piston crevice
and cylinder wall. The number of cell layers in the cylinder was controlled according to the piston motion to model the out-flow
of unburned hydrocarbons from the piston crevice during the expansion stroke. The effects of engine operational conditions
on the oxidation rate were examined at several engine speeds and load conditions, and the sensitivity of the oxidation rate
to the piston crevice volume was also evaluated. Finally, the new one-step oxidation model was applied to a three-dimensional
computational mesh that modeled the three-dimensional engine geometry and piston-valve motions to simulate the oxidation of
unburned hydrocarbons in a real engine condition. 相似文献
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2011年4月19日,陕西法士特齿轮有限责任公司与威伯科汽车控制系统公司在2011上海国际车展上举办发布会,双方联袂合作、精心打造的重型机械式自动变速器(AMT)F-Shift全面投放市场,此举将进一步加快AMT在中国市场的应用. 相似文献