Research And Optimization Of NVH Performance Of Automotive Air-conditioning Pipeline

Vibration and noise of automobile air conditioning compressor is the main noise source of air conditioning system.The noise of the compressor will be transmitted to the vehicle through the connecting pipe of the air conditioner,and the pipeline should have good performance of noise elimination and fluid dynamic performance from the angle of blocking noise and not affecting normal operation of compressor.Air conditioning pipelines are composed of aluminum pipe,tube,mufflers and cooling pipes.Based on the professional acoustic analysis software LMS.Virtual.lab and fluid calculation software FLUENT,the finite element method is used to calculate the transmission loss and pressure loss,main evaluation index of acoustic performance and hydrodynamic properties,by numerical simulation.The effect of eccentric distance,expansion chamber length,resonator,connection mode,bending tube and the skin tube structure on the whole acoustic performance are discussed,and the pressure loss of different pipelines are calculated.Based on pipeline calculation of the acoustic performance and hydrodynamic performance,then the improving suggestions are put forward.The results show that the air conditioning pipeline performance is improved after improved design.Through the test of experiment on vibration and noise of automobile air conditioning compressor,the compressor noise is found mainly in the 100Hz-2000 Hz frequency range and increases with the increase of rotational speed.The target frequency is provided for the calculation of the acoustic transfer function.After the acoustic test of pressure pipeline,we found that the transfer function curve has good consistency in the peak compared with the simulation curve.The results verified the simulation reliability.