配气机构动力学模型的比较研究

Comparison of valve train dynamic models

针对缺乏模型合理性评价依据的问题,提出配气机构动力学模型评价方法.以170F柴油机为例,建立单质量、二质量和四质量三种配气机构动力学模型,并相应进行气门动态特性试验研究.比较三种动力学模型计算稳定性,并以标准差、功率谱和离散小波分解(DWT)三种方法比较计算结果与试验结果的一致性.结果表明,离散小波分解能够准确反映计算结果与试验结果在时域和频域的差异,可作为动力学模型计算与试验吻合程度的判定依据.与单质量和四质量模型相比,二质量模型结构合理,计算稳定性好,计算结果与试验更加吻合.

To give reasonable evaluation of models, valve train dynamic models criteria were brought forward. A 170F diesel valve train was taken as example, one-mass, two-mass and four-mass models were built and the valve dynamic characteristics experiment was also carried out accordingly. Models computation stability was compared, and standard deviation, power spectrum and dispersed wavelet transform （DWT） methods were used to appraise the agreement between computed and experimental data. Comparison results show that DWT method can reflect the difference of computed and experimental data in time and frequency domain, and can be used as the criteria of dynamic model validity and applicability. Compared with one-mass and four-mass models, two-mass model is simpler and more rational, and its result accords well with experimental result.