A Study On Pass-by Accelerating Noise Control Of Mini-vehicle

As the state limit noise data greatly, it is very important project to control the automobiles noise, it has transformed great project for automotive enterprise. this paper aiming at the regulation of limits and measurement methods for noise emitted by accelerating motor vehicles (GB1495-2002), we find the mini-vehicle is not according to the regulation standard (GB1495-2002), so we must decrease noise for mini-vehicle. Using noise source spotting method is identification for mini-vehicle noise, it sure main noise of mini-vehicle. Adopting method of sound intensity measurement are noise source spotting in mini-vehicle surface, in the process of the contour of sound intensity and frequency spectrum analysis, we are sure that engine noise and exhaust noise radiating are bigger. Using expurgation method divide combustion noise from mechanical noise, it showed combustion noise is main noise. Method of sound intensity measurement and surface vibration is noise source identification for engine noise, we find that radiating noise of oil sump tank and delivery manifold shield and cowl hood is biggest. Based on analysis result of noise source spotting show that it is bigger for exhaust noise, in the process of round pressure of insertion losing measurement, we find that it is bigger for gas-stream noise and it is higher for high frequency noise. Improved corrective six recommendation, this muffler are 3-5dB(A) than original muffler decrease. According to modal analysis, we improve the oil sump tank and the delivery manifold shield; using theory of low vibration, we design elastic tongs and rubber washer; according to theory of noise isolation, based on economy and rejection and running, we design the bottom acoustic shield of mini-vehicle with compound material of sound absorption. The mini-vehicle in acoustic shield proceed pass-by accelerating measurement, it show the pass-by accelerating noise of the mini-vehicle is attenuated apparently. The pass-by accelerating noise of the mini-vehicle is obviously decreased from 75.5dB(A) to 73.7dB(A). The mini-vehicle pass-by accelerating noise is conformity with GB1495-2002.