493型柴油机的气道改进设计及其性能实验研究

发布时间：2018-02-22 20:46

本文关键词： 两气门螺旋气道排气道气道稳流试验　出处：《湖南大学》2016年硕士论文　论文类型：学位论文

【摘要】：柴油机的螺旋进气道所组织的进气过程决定了进入柴油机气缸内的气流运动方式及进气与柴油所形成的混合气的质量。进气的流动特性对柴油机气缸内混合气形成与燃烧以及燃烧后的生成物成份等起到重要的作用,进气质量的优劣直接影响柴油机的功率、油耗、排放和噪声等技术指标。在目前对环境保护意识不断增强及排放法规的要求越来越严格的大环境下,对于一款柴油机的开发环节中,排放性能摆在优先的位置,对进气道的优化改进也变得必要而紧迫。在充分研究与课题相关的国内外相关文献基础上,论述了常用的气道测试评价方法并对进气道流通特性常用的流量系数和涡流比这两个评价参数的相关计算公式进行了推导,介绍了研究过程所使用的气道稳流试验台的布置及工作原理。同时结合493型柴油机开发过程中所采用缸盖气道在稳流台架测试分析后再与柴油机实际台架验证相结合的方法,对该型号柴油机的进、排气道分别进行了改进。主要完成研究内容如下:(1)依据某493型柴油机原气道相关参数及性能,介绍了气道设计的设计经验取值、原气道匹配的气门设计尺寸及相关影响参数分析、原柴油机的进气道参数及实际台架试验结果和原气道方案的柴油机性能及数据。并以此提出优化改进方向。(2)扩大进气道最小截面内侧并抬高凸台再扩大进气门座圈等共5轮次的修正、改进工作。经过进行到第4种改进方案后及修正进气道参数后结合对应的台架试验验证。得出该机型的相对匹配的进气道参数范围并依此进行了第5轮的改进方案,最终完成与该型柴油机所匹配的进气道的设计工作。(3)充分考虑了优化方案在实际的改进难度,提出了最终的优化改进方案,并对该方案下的柴油机进行了台架性能测试,并针对性的优化了排气道。对于排气道,进行了喉口位置结构优化及扩大排气门座圈的方式,使排气过程能量损耗降低,并提高增压器对废弃能量的利用,实现了该型发动机在对进气道优化后性能得到进一步优化。
[Abstract]:The intake process of the helical inlet of a diesel engine determines the way of air flow into the cylinder of the diesel engine and the quality of the mixture formed by the inlet and diesel. The flow characteristics of the intake determine the mixture form in the cylinder of the diesel engine. Formation and combustion, as well as the composition of the product after combustion, play an important role. The quality of intake air directly affects the technical indexes of diesel engine, such as power, fuel consumption, emission and noise, etc. At present, the environmental protection consciousness is increasing and the requirements of emission regulations are becoming more and more strict. In the development of a diesel engine, the emission performance is given priority, and the optimization and improvement of the intake port becomes necessary and urgent. In this paper, the commonly used methods for evaluating the flow characteristics of the inlet are discussed, and the formulas for calculating the flow coefficient and the eddy current ratio of the two evaluation parameters are derived. This paper introduces the layout and working principle of the port steady flow test bench used in the research process. At the same time, the method of combining the cylinder head port with the diesel engine actual bench verification after testing and analyzing the steady flow table is adopted in the development process of 493 diesel engine. The intake and exhaust ports of this type diesel engine are improved respectively. The main contents of the research are as follows: 1) according to the related parameters and performance of the original port of a 493 diesel engine, the design experience of the port design is introduced. Analysis of valve design size and related influence parameters of original port matching, The parameters of the inlet port of the original diesel engine and the actual bench test results, and the diesel engine performance and data of the original port scheme are presented. The direction of optimization and improvement is proposed. 2) the minimum cross section of the inlet port is enlarged and the inner side of the inlet port is enlarged and the intake valve seat is enlarged by raising the convex table. Correction of a total of 5 rounds of circles, etc., Improvement work. After the fourth improved scheme and the modification of inlet parameters are combined with the corresponding bench test verification, the relative matching range of inlet parameters of the model is obtained and the fifth round improvement scheme is carried out accordingly. Finally, the design of the intake port matched with this type diesel engine is finished. The difficulty of the optimization scheme is considered, and the final optimization improvement scheme is put forward, and the performance of the diesel engine under this scheme is tested. For the exhaust duct, the throttle position structure optimization and the way of expanding the exhaust valve seat ring are carried out to reduce the energy loss in the exhaust process and to improve the utilization of the waste energy by the supercharger. The performance of the engine is further optimized after optimization of the intake port.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK423

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