Pass-by Noise Analysis And Decline Noise Measure Of BJ6112 City Bus

When the social competition becoming more and more intensive, people eagerly need a quiet environment for rest and living . As one main source of environment noise , automobile noise must be controlled strictly . Additionally , Fast living rhythm makes people more dependent on automobile and spending more time on it ,witch indicates that automobile has really become another rest place , As a result ,the reduction of automobile noise is more important to build a quiet rest condition in the automobile . There for , the automobile noise control is very necessary both to the outside environment and inside condition of automobileThis paper is aiming at BJ6112 city bus. First, it depicts the reason of voice coming into being, the analysis method and measurement of noise. And it introduces the theory of noise control, the reason of noise by automobile accelerating. Then, It introduces how to identify the main noise source. In the progress, it identifies the noise source main by measuring the sound intensity. At last, it research the muffler and cooling system in theory simply for reducing noise. On the base of the research, it confirms the blue print of reducing noise of BJ6112 bus. On the blue print for exhaust system, it uses double muffler. On the blue print in cooling system for reducing noise it uses electrical fan controlled by water temperature (this method is the first in domestic). On the blue print in engine for reducing noise it main controls the noise by the route of sound radiating.By using above measures of noise control, the pass-by noise of BJ6112 city bus is declined apparently. And the effect of noise control is satisfied. The pass-by noise of BJ6112 is obviously decreased from 86.2dB(A) to 80.1dB(A). The noise index has declined 3.9dB(A) compared with domestic statute(GB 1495-2002). At the same time , the fuel consumption of BJ6112 is decreased to a certain extent.