Research On Transmission Characteristics And Reduction Method Of Automotive Fuel Tank Sloshing Noise

The interior noise of passenger cars,regarded as an important indicator of ride comfort,has caused wide concern by manufacturers and users.With the tireless efforts of the researchers,the noise from engine and drive system has been reduced to a low level by some denoise methods.In the meantime,the fuel tank sloshing noise after car brake became a problem.When a car brakes,the fuel sloshes around in the tank,making boring noise which can be transferred into the car.In this article,the transmission characteristics of definite types of fuel tank has been studied with bench experiment and car brake experiment.According to the mechanism of fuel sloshing noise,noise excitation by a loudspeaker has been used to simulate the slosh noise,and force excitation by force hammer has been used to simulate the clunking noise of the tank.In the bench experiment,the noise and force excitation were applied on the tank,and the excitation and response was recorded to analyze the transmission characteristics of two types of noise.After analyzing the experiment data,the transfer function between the excitation and vibration of the surface of tank was calculated.In order to study the transmission characteristics of the fuel tanking sloshing noise transferred by each structure-borne path and air path,car brake experiment has been designed.The excitation data of each transfer path and the acoustic response data inside the car were recorded in the experiment.With the operational transfer path analysis(OTPA)method,the transfer function matrix of the excitation and acoustic response was calculated.Comparing the calculated value and the measured value of sound pressure inside the car,consistent results could be get,and the correctness of OTPA method was verified.The sound pressure contribution of each transfer path were calculated and studied.Measures of vibration and noise reduction were discussed from the point of noise transmission,and research was made on depressing the sloshing noise resource,reducing force transmission and improving acoustic sensitivity.The relationship between damping effect and mobility of body,fuel tank and antivibration pad,was proved theoretically.The design scheme of anti-vibration pad is figured out: material properties testing,mobility testing and calculating the size of anti-vibration pad.