【作者】 尤彦彦；

【导师】 周从钜；

【作者基本信息】 广西大学 ， 农业机械化工程， 2004， 硕士

【摘要】 文章首先简要介绍汽车冷却系统的组成、分类及其重要性，接着论述后置大客车冷却不足的原因及过热对发动机可能产生的影响。之后，在针对原因寻找解决对策的过程中提出：从冷却液角度出发来解决后置车冷却不足有着很强的理论性和实用性。选择具有高沸点特性的醇类物质乙二醇作为冷却液在N485Q柴油机上进行高温冷却试验。液冷和水冷的对比试验表明：采用液冷可以提高发动机的许用环境温度，增强冷却系的冷却强度，同时得出液冷对发动机动力性、经济性和排放的影响规律，以及发动机在不同工况下运转，冷却液的最佳浓度不一样的结论。 接着在性能试验的基础上，运用多因素二次正交回归旋转组合试验的设计方法，选择冷却液沸点、环境温度、转速、负荷四个调整参数进行试验，研究它们的匹配对发动机功率、油耗和烟度的影响，建立相应的数学模型。利用计算机寻优，对标定功率和最大扭矩工况下的六个方程进行优化，得出各自理论最优值及相应参数值，并通过试验验证。 研究结果表明：采用一定浓度的乙二醇水溶液做冷却液，的确能够解决后置车的冷却不足问题，并能在一定程度上提高发动机的动力性，经济性，降低排放，达到节能节油、降污效果。该结论对乙二醇在实现高温冷却方面的研究和采用将起到一定的推动作用。更多还原

【Abstract】 The thesis firstly simply introduces the cooling system’s composes, classifies and its importance. Then the cause of overheat for the rear -mounted and the effect on engine performance are discussed. Next, in the process of looking for the method solving the overheat, coolant is proposed. This way is very theoretical and practical. Ethylene glycol that is a glycol matter with high boiling point character is selected to carry out the experiment. Thus, the experiment of contrasting the liquid cooled with water cooled is carried out on N485Q diesel engine. The research shows adopting the liquid cooled can improve the cooling strength and give the engine more flexibility in accommodating temperature ranges. At the same time, the regular pattern that the fluid cooled effects the power, economy and emission of the engine is obtained. The conclusion that the optimal coolant concentration would be different under different rev and load is also drew.Following, on the base of the performance experiment, the design method of orthogonal regression rotation experiment is put to be used. The experiment of four adjusting parameters (coolant boiling point, environment tempreture, rotation speed, load rate) is designed. The influence of power, oil consumption rate, smoke emission are researched under the different matching of four parameters. The corresponding mathematical models have been established. Finally, with computer looking for the best patameter, the six regressionequations at maximum torque and maximun power are optimized. The best values of each performance index is measured in theory and the corresponding values of adjusting parameters are concluded. The result is in good accord with experiment date.The research result shows that the problem of overheating of rear-mounted is surely resolved by adopting ethylene glycol aqueous solution with a certain concentration as coolant. The power and economic performance are improved . The emission is reduced. The energy and oil saving and pollution reducing are reached. To a certain extent, this conclusion have an affect on the reseach and appliance of ethylene glycol on the high tempreture cooling .更多还原