The Level With Pass-by Accelerating Noise Of Great Model Passenger Accommodation Vehicle In Our Country And The Study Of Decline Noise Measure

This study first give a expatiation on the harm of noise pollution in world and the development trend in the future ,It indicate that task of reducing the noise of vehicle is becoming strictness with the development of automotive industry.After introduceing the theory of noise ,this study analyse the create process of vehicle noise, combine with the structure of vehicle and using character,we can make a conclution that Pass-by Accelerating Noise of vehicle is composed of vibration on vechicle and air vortex in some assembly.It is composed of engine Noise,exhaust noise,ntake Noise,fan Noise, transmission Noise,tyre Noise and Noise of air resistance. this study also point out the difference of noise standard in china and abroad,emphasize carrying out of noise standard GB1492一2002 have got a impetus at controlling the increase of vechicle noise and forcing the manufacture and society improve environment consciousness. A detail introduction of noise standard GB1495-2002 is carried out on testing condition and instrument used. This study give out approximately one thousand noise testing date about first phase of noise standard GB 1495-2002 from model year 2002 to model year 2004 and that about second phase from model year 2004 to model year 2006. All of these give a conclution of noise level on M1 passenger car and M3 passenger car;①For M1 passenger car , 43.5 percent testing samples are inside the limited of first phase and second phase of noise standard GB 1495-2002 before 2005 medol year, the average noise level is from 72.8dB to75.4 dB. After 2005 medol year, the average noise level is decreaced greatly, About 21.5 percent testing samples are from 73.5dB to74.0 dB, the average noise level is from 71.8 dB to 72.9 dB, Noise level is increased with the adding of GVM, Carrying out of second phase limited of noise standard GB1492一2002 have got a great impetus at decreasing of vechicle noise level of M1 passenger car, The average noise level of M1 passenger car is decreased 2～3 dB, Some M1 passenger car are not satisfied noise standard GB 1495-2002 have quited the market.②For M3 passenger car with engine power less than 150kW, 56.8 percent testing samples are not meet the limited of first phase, and not more than 6.8 percent testing samples meet the limited of second phase of noise standard GB 1495-2002 and no one meet the limited of ECE R51/02 before 2005 medol year. After 2005 medol year, the average noise level is decreaced greatly, 97.7 percent testing samples meet the limited of second phase, and 11.4 percent testing samples meet the limited of ECE R51/02 thereinto .③For M3 passenger car with engine power more than 150kW, 4.9percent testing samples are not meet the limited of first phase of noise standard GB 1495-2002 before 2005 medol year, many testing samples'noise level are between 83 dB and 85dB, this is 60.5 percent of testing samples ,no one meet the limited of ECE R51/02. After 2005 medol year, 87.3percent testing samples are between 80 dB and 83dB, testing samples meet the limited of second phase are 97 percent, and 10 percent of testing samples meet the limited of ECE R51/02. After carrring the limited of second phase of noise standard GB 1495-2002, the average noise level is decreaced2～3dB for M3 passenger car with engine power more than 150kW.About how to increase noise level for M3 passenger car, A characteristics of noise sources have been attained on a M3 passenger car, we can make a conclution that exhaust noise and engine noise are the main noise sources on a M3 passenger car with high noise level.At last ,this study make a analysis on big passenger car, piont out designing a reasonable muffler to decrease exhaust noise is the best way to decrease the noise level . we suggest carry out noise standard of ECE R51/02 step by step in china can help us to decrease the general noise level of big passenger car.