高压共轨系统高压管路压力波动特性仿真研究及结构优化

发布时间：2018-06-10 17:38

本文选题：高压共轨 + 一维仿真　；参考：《北京交通大学》2016年硕士论文

【摘要】：随着发动机电子控制技术的发展,电控柴油机被广泛应用于汽车、机械等多个工程领域。能源危机的出现及环境污染的加重使人们对柴油机效率及排放越来越关注。喷油过程的精细化控制是提高发动机燃油经济性及排放性能的重要手段。高压共轨系统因可实现对喷油压力、喷油次数、喷油量及喷油规律的较为精确的控制而成为国内外研究的重点。然而,由于发动机持续不断的喷油、供油,高压管路中不可避免的会产生压力波动,对喷油过程的精确控制产生不利影响。先进的轨压控制技术是维持共轨管中压力稳定的重要途径,同时,通过对高压管路结构的合理匹配和设计也是改善高压管路压力波动特性的有效方式。本文对高压管路中压力波动特性进行了较为深入的研究,并对高压管路的结构进行了优化。本文对高压共轨系统组成及工作原理进行了说明,对主要部件的数学模型进行了阐述,利用AMESIM软件建立高压共轨系统一维仿真模型,通过将仿真结果与试验数据进行对比分析,验证了模型的准确性。利用已经建立的高压共轨系统一维仿真模型,研究结构参数对高压管路压力波动特性的影响。通过改变供油管长度、内径,共轨管长度、内径、容积、长径比,高压油管长度、内径,研究高压管路结构变化时压力波动程度的变化规律；通过改变供油管、共轨管、高压油管的容积及长径比,分析高压管路形状对轨压建立时间的影响。建立高压管路流场三维模型,在划分模型网格时通过对模型的合理分块,使模型网格全部为六面体网格,利用FLUENT软件开展高压管路三维流场仿真计算,通过对高压管路燃油压力云图、速度云图及矢量的分析,结合一维仿真计算结果,对高压管路中压力波的产生、传播及燃油流动过程进行了分析。用频谱分析的方法,对不同工况及高压管路结构下一维仿真计算得到的共轨管压力波动曲线进行分析,总结出共轨管压力波动频率、振幅受高压共轨系统运行及结构参数的影响规律。最后,在前文研究的基础上,通过设计正交试验,以提升高压共轨系统综合性能为指标,以高压管路容积大小作为限定条件,对供油管长度、内径,共轨管长度、内径及高压油管长度、内径进行匹配并开展一维仿真计算,得到两种高压管路容积限制条件下各指标都较优的管路结构参数,结论为：高压管路容积限制在60m1以内时,供油管长度取300mm、供油管内径取4mm、共轨管长度取450mm、共轨管内径取12mm、高压油管长度取300mm,高压油管内径取4mm时,高压共轨系统综合性能较优,优化后的轨压平均压力波动量数值较优化前降低31.24%,循环喷油量提升0.57%,喷油量平均偏差降低了39.84%；高压管路容积限制在100ml以内时,供油管长度取300mm、供油管内径取4mm、共轨管长度取750mm、共轨管内径取12mm、高压油管长度取300mm,高压油管内径取3.5mm时,高压共轨系统性能指标提升,优化后的轨压平均压力波动量数值较优化前降低30.53%,循环喷油量提升0.51%,喷油量平均偏差降低了52.38%。
[Abstract]:With the development of engine electronic control technology, electronic control diesel engine is widely used in many fields, such as automobile, machinery and other engineering fields. The emergence of energy crisis and the aggravation of environmental pollution make people pay more and more attention to the efficiency and emission of diesel engine. The fine control of the fuel injection process is an important hand to improve the fuel economy and emission performance of the generator. The high pressure common rail system has become the focus of research at home and abroad because of the precise control of the injection pressure, the number of fuel injection, the amount of fuel injection and the law of injection. However, the pressure wave will inevitably be produced in the continuous injection of the engine, the oil supply and the high pressure pipeline, which has a negative effect on the precise control of the injection process. Advanced pressure control technology is an important way to maintain pressure stability in common rail. At the same time, the rational matching and design of high pressure pipeline structure is also an effective way to improve the pressure fluctuation characteristics of high pressure pipeline. The pressure fluctuation characteristics in high pressure pipeline are studied in this paper, and the structure of high pressure pipeline is carried out. In this paper, the composition and working principle of the high pressure common rail system are explained, the mathematical model of the main components is expounded, and the one dimension simulation model of the high pressure common rail system is established by using AMESIM software. By comparing the simulation results with the experimental data, the accuracy of the model is verified. One dimension simulation model of the system is used to study the influence of structural parameters on pressure fluctuation characteristics of high pressure pipeline. By changing the length, diameter, diameter of common rail, inner diameter, volume, length diameter ratio, length and diameter of high pressure oil pipe, the variation law of pressure fluctuation in high pressure pipeline structure is studied, and the oil supply pipe, common rail tube and high pressure oil are changed by changing the oil pipe. The effect of the volume and the length to diameter ratio of the tube is analyzed. The three-dimensional model of the high pressure pipeline is established. The three-dimensional model of the high pressure pipeline flow field is established. The model grid is all hexahedral mesh through the reasonable partition of the model mesh. The three-dimensional flow field simulation of high pressure pipe road is carried out by FLUENT software, and the high pressure pipeline is burned through the high pressure pipeline. With the analysis of oil pressure cloud map, velocity cloud map and vector, combined with one dimension simulation results, the production, propagation and fuel flow process of pressure waves in high pressure pipeline are analyzed. The pressure wave curve of common rail pipe obtained by one dimension simulation under different working conditions and high pressure pipeline structure is analyzed by spectrum analysis, and the conclusion is summarized. The frequency of common rail pressure fluctuates, the amplitude is influenced by the operation of the high pressure common rail system and the influence of structural parameters. Finally, on the basis of the previous study, through the design of orthogonal test, the comprehensive performance of the high pressure common rail system is improved. The length of the pipe, the inner diameter, the length of the common rail pipe, the inner diameter and the inner diameter are taken as the limit of the high pressure pipe volume. The length and inner diameter of the high pressure oil pipe are matched and one dimension simulation calculation is carried out. The parameters of the pipeline structure are better under the conditions of two high pressure pipelines. The conclusion is that the length of the oil supply pipe is 300mm, the inner diameter of the oil supply pipe is 4mm, the length of the common rail pipe is 450mm, the inner diameter of common rail pipe is 12mm, high. When the length of the pressure oil pipe is 300mm and the inner diameter of the high pressure pipe is 4mm, the comprehensive performance of the high pressure common rail system is better. The average pressure fluctuation of the rail pressure after the optimization is 31.24% lower than that before the optimization, the amount of circulating fuel injection is 0.57%, the average deviation of the fuel injection is reduced by 39.84%. When the volume of the high pressure pipeline is limited to 100ml, the length of the pipe supply is 300mm, supply oil. When the inner diameter of the tube is 4mm, the length of the common rail pipe is 750mm, the inner diameter of the common rail tube is 12mm, the length of the high pressure oil pipe is 300mm, when the inner diameter of the high pressure oil pipe is 3.5mm, the performance index of the high pressure common rail system is improved. The average pressure fluctuation of the rail pressure after the optimization is 30.53% lower than that before the optimization, the circulation fuel quantity is raised by 0.51%, and the average deviation of the fuel injection is reduced by 52.38%.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TK423

【相似文献】