提取内燃机燃烧压力高频成分进行压力高频振荡研究

ANALYSIS OF HIGH-FREQUENCY PRESSURE OSCILLATION BY OBTAINING HIGH-FREQUENCY COMPONENT FROM COMBUSTION PRESSURE OF INTERNAL COMBUSTION ENGINE

研究内燃机缸内压力高频振荡的机理以及压力高频振荡对燃烧噪声的影响。利用小波分析技术确定缸内压力高频振荡出现的范围,从而确定了燃烧室空腔声模态模型的对应曲轴转角范围。用声响应法和有限元法分别测量和计算不同曲轴转角下燃烧室空腔声模态,并对测量值和计算值对应曲轴转角进行了温度修正,模态试验结果与有限元计算结果较吻合。并对测量的缸内燃烧压力信号和噪声信号进行了分析。研究结果表明:缸内燃烧压力高频振荡是燃烧室的多阶共振频率受到激励引起共振的结果,燃烧压力高频振荡是影响燃烧噪声的重要因素。

The mechanism of the high-frequency pressure oscillation and its effect on combustion noise are studied. The appearance ranges of the high-frequency pressure oscillation are defined by the method of the wavelet analysis and the corresponding crankshaft angle ranges of the chamber cavity model also are obtained. The acoustic model of the chamber cavity with different crankshaft angle is tested by the acoustic response method and computed by the finite element technique. Both the results of the calculated and tested are modified by corresponding crankshaft angle temperature and they are practically equal. The combustion pressure and noise are studied by the test parameters. The results show that the high-frequency pressure oscillation is aroused by the combustion chamber's several ranks resonance. The high-frequency oscillation of combustion pressure is the important effect factor of the combustion noise.