以一台4缸发动机为例,分析对比安装适当的风扇前后样机噪声的心理声学参数值,发现安装合适的风扇后虽然测点附近噪声的A计权声压级和响度值都变大,但是相对满意度均值提高约5%,说明整机噪声听起来更加容易被接受,达到了改善发动机噪声声质量和制冷的双重效果。研究发现,适当地增加噪声中的中低频成分(1,kHz以下)或降低高频能量成分(2~4,kHz)可以达到改善发动机噪声声质量的目的。
Using a four-cylinder engine as a sample,the psycho-acoustic parameter analysis is made for the engine with and without fan.It is found that A-weighted sound pressure level and loudness increase in the presence of fan.However,the sensory pleasantness improves by 5%,which indicates the acceptable engine noise and achieves the effectiveness of improving engine noise and cooling.Results show that increasing low frequency(below 1,kHz)and decreasing high frequency(2-4,kHz)can improve the sound quality.