Research on active noise control technology in hybrid vehicle exhaust systems
Exhaust system noise,as one of the main sources of noise in hybrid vehicles,needs to compensate for the shortcomings of passive mufflers in noise reduction,an active noise reduction methodology was introduced to alleviate exhaust system noise.Initially,the Least Mean Squares(LMS)algorithm was employed to discern the transfer function of the secondary path,facilitating preemptive compensation of the amplitude and phase of the control signal within the active noise reduction system.Subsequently,the engine speed corresponding to the order noise of the exhaust system was utilized as the reference signal for the active noise reduction system.Leveraging the Filtered-x Least Mean Squares(FxLMS)algorithm,the system computes an anti-phase sound wave signal at the same frequency and amplitude as the original noise,thereby effectuated a reduction in order noise within the 60～300 Hz frequency range.The experimental results showed that the method of this paper had a significant effect on noise reduction under idling and accelerating conditions,with a reduction of 5.6 dB(A)in the RMS value within 60～300 Hz under idling conditions,and an average optimisation of the 2nd order noise at the exhaust port under accelerating conditions of about 15 dB(A).The results provide references for noise reduction research in exhaust systems.
active noise controlengine order noiseFeedforward FxLMS algorithmexhaust system
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