关键词: 发动机；主动降噪；辨识方法；DSP 实现

Abstract: Active noise reduction technology has obvious advantages in low-frequency noise control. It uses the speakers in the car to cancel the sound waves to achieve noise reduction. In this paper, the frequency sweep method is used to carry out the calibration process of active noise reduction, and the controller and the original car line matching are realized on a four-cylinder engine model, and the original car audio is used to build the in-car engine active noise reduction system. Using MATLAB to build a simulation model to verify the adaptive notch algorithm, derive the sound transfer function formula in the car, and derive the identification results. From the engineering point of view, the matching method of the controller and the vehicle interface is introduced. Finally, digital signal processing (DSP) technology is used to verify the real vehicle effect, the second, fourth, and sixth-order noise of the engine is reduced under the acceleration condition of locking the second gear, and the sound pressure level overall (OA) value of 30～300 Hz is reduced by 4 dB at the maximum.

Key words: Engine; Active noise control; Identification method; DSP implementation