Study On Double Secondary Sound Source Active Noise Control System In Vehicle

Noise pollution has become the third largest pollution besides water and air pollution. In recent years, the noise of the car has caught people’s attention, especially the interior noise. Traditional passive noise control technology can not meet the low-frequency noise to reduce noise, but the active noise control technology can achieve good results in reducing the noise of the low-frequencynoise.Based on the study of active noise control technology, this paper uses of acoustic simulation software to analyze the distribution of sound field of enclosed space inside the car and it can reduce the sound field of noise actively. Meanwhile, this paper proposed optimal laying of secondary sound sources of the enclosed space inside the car.This paper summarizes a number of research results in domestic and abroad and methods of reducing source noise. It illustrates the necessity and development trend of active noise control; the essence of active noise control is the stack of the secondary sound field produced by human primary sound field in accordance with the law ofacoustic, so as to achieve the purpose of the muffler. Based on considerations of reliability, this paper conducted a simulation to prove this conclusion.Vehicle enclosed space can be approximated as elasticity enclosed space, therefore, this paper clarifies Active Noise Theory and active noise control theory of enclosed space. Meanwhile, this paper uses a domestic car specific conditions to analyze of Acoustic coupling of the finite element model cars. We can get the conclusion that the sound field of enclosed space for the car doesn’t need to consider the effects of air dielectric to structure modal.According to finite element analysis method, this paper constructs the finite element model of interior enclosed space and uses LMS Virtual.lab Acoustic solving the acoustic coupling modes. After the analysis of the distribution of the sound field of the enclosed space inside the car, this paper tries to use two monopole source of interior space enclosed muffle and achieved good results overall. The sound pressure of front occupants’double ear will decline with local noise active Noise Control system.The location ofsecondary sound source in the car has a certain impact on the silencing. In laying the secondary sound source, people consider the feasibility of silencing effect and secondary sound sources installed to place the double the secondary sound source in different locations, and then ultimately come to the best interior space enclosed laying position.