汽车三元催化器堵塞状况评估方法研究

发布时间：2018-02-03 14:58

本文关键词： 汽车三元催化器堵塞图像处理流场仿真　出处：《吉林大学》2016年硕士论文　论文类型：学位论文

【摘要】：汽车三元催化器作为排气系统中的重要组成部分,对排放污染物的转化率起着重要作用,同时其对发动机的运行效率也有较大影响。如果三元催化器堵塞,不仅会使汽车功率下降,增加燃油消耗量,同时由于发动机在高背压条件下工作会产生大量的热,容易使发动机发生故障,并产生大量的有害气体,造成环境污染。针对这些情况,需要及时掌握三元催化器的运行状况,对失效的三元催化器进行更换。因此,本文基于图像处理技术提出了一种新的三元催化器堵塞状况的评估方法。论文在综述国内外参考文献的基础上,基于图像处理技术提出了一种新的三元催化器堵塞状况评估方法;分析了三元催化器基本概念以及其失效形式,设计了催化器堵塞端面图像采集平台,通过该平台得到了稳定可靠的三元催化器载体端面图像;对三元催化器端面图像进行了预处理,得到了三元催化器端面的二值图像,通过对二值图像进行膨胀、腐蚀、开运算、闭运算等处理,确定了载体端面所在的区域并且得到了三元催化器完整的载体端面图像;通过对三元催化器局部图像的处理,验证了本研究中图像处理算法的有效性,为其实际应用提供了依据;完成了三元催化器端面通过率、堵塞率的计算,计算结果与实际情况相符;通过对三元催化器内部流场的理论分析,建立了三元催化器的三维模型,使用流体力学软件对其进行网格划分,对划分完网格的模型进行仿真,得到三元催化器理想状态下内部流场的特征;对不同堵塞程度的三元催化器进行仿真试验,得到了不同堵塞状态下三元催化器内部流场的特征,发现随着堵塞率的增高,三元催化器内气体流速增加,进气管的压力增大,确定其对发动机运行工况的影响。论文研究成果可为进一步进行三元催化转化器堵塞率量化研究及定量研究催化器堵塞对车辆动力性及排放影响规律提供技术支持,也为三元催化器的定量检测工作提出了一种新的思路。
[Abstract]:As an important part of the exhaust system, the three-way catalytic converters play an important role in the conversion of pollutants, and also have a great impact on the engine efficiency, if the three-way catalytic converters are blocked. It will not only reduce the automobile power and increase fuel consumption, but also produce a lot of heat when the engine works under the condition of high back pressure, which will easily cause the engine to break down and produce a large number of harmful gases. Environmental pollution. In view of these circumstances, it is necessary to grasp the operation status of the ternary catalytic converters in time, to replace the failed three-way catalytic converters. Based on the image processing technology, a new method for evaluating the clogging condition of ternary catalytic converters is proposed in this paper, based on the review of references at home and abroad. Based on the image processing technology, a new method for evaluating the clogging condition of ternary catalytic converters is proposed. In this paper, the basic concept and failure form of the ternary catalytic converters are analyzed, and the image acquisition platform for the blocking end surfaces of the catalytic converters is designed, through which the stable and reliable end-face images of the carrier of the catalytic converters are obtained. The binary image of the end-face of the ternary catalytic converter is obtained by pre-processing, and the binary image is processed by expansion, corrosion, open operation, closed operation and so on. The region of the terminal surface of the carrier is determined and the complete image of the terminal surface of the carrier is obtained. The validity of the image processing algorithm in this study is verified by processing the local images of the ternary catalytic converters, which provides a basis for its practical application. The calculation of the pass rate and clogging rate of the end face of the three-way catalytic converter is completed, and the calculated results are in accordance with the actual situation. Based on the theoretical analysis of the internal flow field of the three-dimension catalytic converter, the three-dimensional model of the three-dimensional catalytic converter is established, and the model is meshed by using the fluid dynamics software, and the model of the three-dimensional catalytic converter is simulated. The characteristics of internal flow field in ideal state of ternary catalytic converters are obtained. The characteristics of internal flow field of ternary catalytic converters with different plugging conditions were obtained by simulation experiments. It was found that the gas flow rate increased with the increase of clogging rate. The pressure of the intake pipe increases. The research results can provide technical support for further quantitative study on the blocking rate of catalytic converters and for the quantitative study of the influence of catalytic converters on vehicle power and emissions. Hold. It also provides a new idea for quantitative detection of ternary catalytic converters.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U464.134.4

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