Active control of vehicle interior engine noise using a multi-channel delayed adaptive notch algorithm based on FxLMS structure

A multi-channel delayed adaptive notch algorithm based on the filtered-x least mean square (FxLMS) structure was proposed for active control of vehicle interior engine noise with prominent harmonic characteristics. First, a complete reference signal model was established utilizing vehicle engine speed. Second, the algorithm procedure was presented systematically, and a new time-delay method was introduced to simplify the filtering process of the reference signal to greatly improve the calculation efficiency. Furthermore, the convergence condition was derived, and mathematical models of the steady-state error and convergence speed were obtained. The simulation results, which were consistent with theoretical calculation values, showed that the two models were highly accurate. They help to theoretically indicate the interval range of the effective convergence coefficient μ and its optimal value. Using the proposed multi-channel delayed adaptive notch algorithm, actual vehicle active noise control experiments were conducted. The results show that, under stationary conditions, the interior overall engine noise reduction in the time-domain reaches 4.05 dB (A), and the corresponding second-order engine noise reduction reaches 13.66 dB (A), however, under nonstationary working conditions, the proposed algorithm still has a good noise reduction effect. This algorithm can be directly applied to the active control of vehicle engine noise and other similar narrowband noise reduction.