Research On The Acoustic Simulation System In Electric Vehicle

With the development of electric vehicles,the requirements of OEMs and consumers for the NVH performance of the electric vehicles are constantly improving.The research focus has been turned into improving the riding comfort and acoustic characteristics of electric vehicles.Sound quality control for low-noise electric vehicles has become a research hotspot.Acoustic simulation system provides drivers with the driving state of the vehicle by sound feedback,and covers the high-frequency electromagnetic noise in the electric car,which improves riding comfort.Moreover,sound customization makes electric cars have sound signature,which helps identify the brand image.Through the establishment of sound source collection scheme,the sound recording in the vehicle with internal combustion engine is carried out under the steady operation conditions,and the engine sound is recognized by the OTPA technology.To have an outstanding sound quality,the recognized engine sound source is filtered,the harmonic order is optimized,and the interception is performed.The sound source samples after optimization are stored to complete the establishment of the sound source sample library.In combination with the design requirements,several algorithmic functional modules are developed.Firstly,the pitch modulation module is established to control the pitch according to the variable rate resampling theory.Secondly,the sound pressure level control module is established to control the synthesized sound pressure level in the vehicle and make it match with the actual working condition.Then the multi-link control module is established to make the sound synthesized by the system have more abundant spectral component changes.The start-stop control module is established,so that the system in the process of stop and re-start smooth access,and avoid the system continuous start and stop caused by the BUS signal jitter;In addition to these main functional algorithm modules,some functional design are added,such as the input signal interpolation module for solving lost signal frame,and the source type selection module.The whole part of the algorithm is built in the MATLAB/Simulink environment.The feasibility and effectiveness of the algorithms are verified by simulation.Last but not least,by utilizing the software engineering method,the algorithm efficiency isoptimized accordingly.By building a Rapid Control Prototype(RCP)system,the real-time verification of the acoustic simulation system algorithm and the debugging of system parameters are carried out.Eventually,on the sound test bench and on the road,the acoustic simulation system in the electric vehicle is tested under various working conditions.Through objective analysis of the experimental results,subjective effect experience and evaluation of the personnel in the driving room,as well as subjective evaluation in the sound quality evaluation room.The results show that the designed acoustic simulation system meets the functional requirements of the project and has the functional characteristics required by the system.