混动总成在怠速充电工况下有疑似咕咕音，进行数据采集和分析后，确定该异响为具有发动机半阶次特征的咕咕音。根据其产生机理分析确定了混合动力总成咕咕音源于轴系扭转振动高谐次分量激励，并由混合动力总成弯扭模态和EGR模态耦合放大产生。由此提出了更换柔性飞轮、增加DHT连接支架、增加EGR螺栓支撑点三个优化方案，最终解决了咕咕音异响问题。针对咕咕音的分析和应对方法对于解决该类问题有较强的参考作用。
A suspected cooing sound was identified in the hybrid
powertrain under the idle charging condition. Data collection and analysis
confirmed that this abnormal sound was a cooing sound exhibiting engine half-order
characteristics. Analysis of the generation mechanism revealed that the cooing
sound originated from excitation by high harmonic components of shaft system
torsional vibration, which was then amplified through the coupling of hybrid
powertrain bending-torsional mode and EGR mode.
Consequently, three optimization schemes were put forward, including replacing
the flexible flywheel, adding a DHT connection bracket, and adding an EGR bolt
support point. These schemes successfully eliminated the abnormal cooing sound.
The analysis methodology and countermeasures provide significant reference
value for addressing similar NVH problems.
