Study On Engine Shell Sound Radiation Control And Prediction

In order to reduce the harmness of noise to the society and link to international practice,our country amend the legislation from time to time.More stringent legislations of vehicle noise appeared,and GB1495-2002《Limits and measurement methods for noise emitted by accelerating motor vehicles》prescribe that the noise limit of vehicle after January 1, 2005 will be striken by 2~4dB. Ameng the noise of vehicle the noise of engine seem to be more important.To control the noise of vehicle,the analyse and study of engine surface is absolutely necessary. The shell such as Oil pan or crankcase are serious problems and must be controlled.Through investigation of the noise source of JS ATV 400,we know that the main noise sourses of the engine are several shells,such as the cylinder head and the right crankcase cover plate etc.As for the crankcase cover plate,The full-scale mock-up by using UG and the fea model in ansys are established,then do the modal analysis. The result is consistent with the experimental result.It show that the fea model builted can reflect the dynamic characterics in effect.Then Ls-DYNA is use to do the transient response analysis in vibration environment,mainly studying the relationship ameng the structural parameter,structural style and structure mode.Base on it,a scheme to restrain the vibration and noise radiation of the crankcase is presented,and then the noise power of the shell after modified is forecasted using vibration and noise method.