A car exterior noise prediction method is presented based on SEA (Statistical Energy Analysis) method and point sound source radiation theory in this paper. The SEA model of the car is built. Input parameters of the SEA model including modal densities, DLFs (Damping Loss Factor) and CLFs (Coupling Loss Factor) of the regular and complicated subsystems are calculated, respectively, by using analytic formulas and finite element method. Excitations of the SEA model are determined by the corresponding rig-testing of the engine and CAE simulation analysis technology. Car exterior noise caused by structure-borne noise of body panels is predicted by the SEA model. The exterior noise radiated from exhaust and tyre noise is calculated according to point sound source formula. Total exterior noises of the car are summed up by means of logarithmic summation approach of noise. Car exterior noise is measured based on ECE R51 regulation. Through the above-mentioned research, the following conclusions can be acquired: (1) A good agreement is shown by comparing predicted and tested results of car exterior noise. The predicted value of car exterior noise is 74.36 dB(A) and the tested result is 72.65 dB(A). The absolute difference value is 1.71 dB(A) and the relative error was 2.35%. Therefore, the car exterior noise method presented in this paper is feasible and effective. (2) Through improving acoustic package of engine cabin, car exterior noise can be controlled effectively and the total SPL (Sound Pressure Level) decreased by 1.10 dB(A). (3) The car exterior noise prediction method proposed in this paper can realise prediction and control to car exterior noise at car R&D stage before the physical prototype manufactured. The effects of the different body sound package schemes on car exterior noise can be predicted, compared and optimised. In addition, influence improving muffler and changing tyre on car exterior noise can also be evaluated by the method.
Research on prediction and control method of car exterior noise
Forschung über Vorhersage und Regelungsverfahren bei Pkw-Außengeräusch
International Journal of Vehicle Design ; 59 , 1 ; 44-60
2012
17 Seiten, 20 Bilder, 1 Tabelle, 15 Quellen
Aufsatz (Zeitschrift)
Englisch
Research on prediction and control method of car exterior noise
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