小波分析在汽车空调启动异响诊断中的应用

摘要

当按下汽车空调启动键（AC ON）后，空调系统工作，车内产生异响。针对车内空调启动异响，探究其产生原因和影响因素以解决该问题。使用B&K信号采集系统对车内噪声信号与压缩机、膨胀阀的加速度信号进行采集。选取适当的小波基和小波参数，对信号进行小波能量谱分析。发现空调启动异响是由压缩机吸合时衔铁的冲击振动引起，并与膨胀阀上的振动相关。对压缩机、空调管路采取隔振减振措施后，压缩机吸合冲击及膨胀阀振动大大衰减，车内的空调启动异响明显减弱。%Abnormal noise starts inside vehicles as soon as the air-conditioning (AC) ON button is pressed and AC system starts working. In this paper, the cause and influencing factors of this AC-ON noise are investigated to solve for the problem. Interior sound pressure and acceleration signals of the compressor and the thermal expansion valve (TXV) are measured using B&K signal acquisition system. The appropriate wavelet base and wavelet parameters are chosen to analyze the wavelet energy spectrum of the signals. It is found that the AC-ON abnormal noise is caused by compressor’s activating impact and the TXV vibration. Countermeasures of isolation and damping are applied to the compressor and the TXV. As a result, the compressor activating impact and the vibration of TXV as well as the AC-ON noise are significantly reduced.