基于缸盖振动信号的发动机排气管堵塞故障分析

现代汽车发动机广泛使用三元催化器进行排放控制,而三元催化器在长期使用过程中容易堵塞,造成发动机排气不畅,影响发动机性能。利用位于发动机缸盖上的振动加速度传感器,提取不同转速下正常状态和堵塞状态的振动信号,通过频谱分析,发现2阶振动幅值有明显变化,经小波包分解求得各频段振动能量,结果表明排气管堵塞后在相同转速下的低频段振动能量都有所减少,而且高转速比低转速减少更加明显,但各频段能量占总能量比重变化不大。此分析结论,可作为发动机排气管堵塞故障诊断的参考依据。

Fault Analysis of Engine Exhaust Pipe Blockage Based on Cylinder Head Vibration Signal

Modern automobile engine widely use three-way catalyst(TWC) to control exhaust emissions,but TWC was easily blocking in the long-term use,which would make exhaust impeded and engine performance deteriorated.By use of vibration acceleration sensor located in engine cylinder,extracting vibration signal of normal and blocked situation at different speed.Spectrum analysis found that 2-order vibration amplitudes are obviously different.Then decomposing vibration signal with wavelet packet and each frequency band vibration energy can be got,result shows that low frequency band vibration energy is reduced in situation of exhaust pipe blocked,and reduction is more apparent at high speed,but ratio of each frequency band energy has little change.This result can be used as a reference for engine exhaust pipe blockage diagnosis.