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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。
Modern automobile engines widely use three-way catalytic converters for emission control, while three-way catalytic converters are easily clogged during long-term use, resulting in poor engine exhaust and affecting engine performance. Using the vibration acceleration sensor located on the cylinder head of the engine, vibration signals of normal state and blocked state at different rotational speeds are extracted. Through the spectrum analysis, it is found that the amplitude of the second order vibration changes obviously. The vibrational energy of each frequency band is obtained by wavelet packet decomposition. It shows that the vibration energy of the low frequency band at the same rotational speed is reduced after the exhaust pipe is blocked, and the reduction of high rotational speed is more obvious than that of the low rotational speed. However, the energy of each frequency band changes little with the total energy. The conclusion of this analysis can be used as a reference for engine exhaust blockage troubleshooting.