直喷式柴油机燃烧压力高频振荡与燃烧噪声的关系

应用声响应法和Sysnoise声学软件进行模态实验和模态分析,研究燃烧噪声高频激励机理．通过有限元方法计算燃烧室空腔在点声源激励下的声压响应,确定了燃烧室空腔在激励力作用下产生较强烈的压力振荡的频率．通过测量发动机缸内压力和噪声,研究燃烧压力高频振荡频率和幅值与时间窗获取的燃烧噪声的关系．燃烧压力高频振荡频率与燃烧噪声高频成分具有很好的对应关系,较高的振荡幅值对应的燃烧噪声值较高．研究结果表明,燃烧压力振荡频率和幅值是影响燃烧噪声高频成分的主要因素．

Relation Between the High-Frequency Oscillation of Combustion Pressure and Combustion Noise of DI Diesel Engine

Sound model experiment and model analysis are carried out with sound response method and Sysnoise sound software, to give the high-frequency stimulation mechanism of combustion noise. With FEM analysis method, the sound pressure response is calculated when stimulated by a point sound source in the combustion chamber, and the frequency of quite violent pressure oscillation is obtained when combustion chamber is stimulated by combustion. The relation between the frequency and amplitude of the high-frequency oscillation of combustion pressure and the combustion noise obtained by designing a time window is investegated by measuring the test parameters. The frequency of the high-frequency oscillation of combustion pressure is corresponding with combustion noise' s high-frequency component and higher amplitude of the high-frequency of combustion pressure corresponds with higher combustion noise. The result shows that frequency and amplitude of the high-frequency oscillation of combustion pressure are the main factor that affects the combustion noise.