Research And Analyze Of Diesel Engine Noise Quality For Motor Vehicle

As the requirement of NVH performance development on the car domain, internal combustion engine noise as the main part of the vehicle noise gradually take more attention by the domestic and international research department's attention. While the traditional A-weighted sound pressure level evaluation index gradually can not meet people's requirement, sound quality is a method that can evaluate noise quality more effective,it consider the characteristics of the auditory and reflect different subjective feeling of the noise.So it provide a new way to evaluate noise.This paper introduces the basic characteristics of human physiological and hearing,based on these theories,we bulit some acoustic quality evaluation parameters using matlab.In order to verify the accuracy of the model,analysing some basic sound signal,and the result is all right.This model makes the critical parameter more clearly with the result plot as pictures,and it's useful to improve the quality of noise.We test the noise of two different diesel engine at nine points using LMS test systerm,then extracting 16 signals as the samples that proceed subjective evalution.After study the effective test results,we find that,the loudness and sharpness influence the satisfaction easily.Using the soft of SPSS Statistics build multivariate regression equation which can refect the relationship between loudness,sharpness and satisfaction very well.With the conclution apply to discriminant the noise quality of two diesel engine,the conclution is that,the sharpness is like to change like parabolic linear while the loudness is become louder.Contrast of A and B diesel engines at full load case,we find the pressure level is similar,but the loudness and sharpness of engine A is clearly bigger than B.So the structure of B type diesel engine is more suitable for improving the hearing comfortable.The engineering example preminary demonstrates the effective of new evaluation method ,provide a new way for evaluting and improving diesel engine sound quality.