Research On Noise Reduction Of Hydraulic Excavator Engine’s Cooling Fan System

Construction machinery had made a great contribution to human society,however,it brought people lots of annoyances such as noises and exhaust emissions.The issue of decreasing the noise of construction machinery had been taken seriously in most of developed countries,and they have already taken a series of measures,and even laws to limit noises coming from it. Therefore,the study on how to reduce the noise of construction machinery is of great meaning.This paper took SWE17excavator as the object of study.The detailed researches are described as follows:First,a series of acoustic tests were done by using DASP system,then,the noise source was identified by analyzing three-dimensional sound intensity maps, frequency spectrum of noise signals and modals of bellmouth.the result would provide valid basis of where should be taken measures to reduce noise.Second, the three-dimensional model of fan and bellmouth of cooling system were built to give assistance to the coming simulation of flow.Third,three-dimensional flow characteristics was simulated to obtain the state of air flow of cooling fan system and its relation to the noise condition.Fourth,optimization were researched by analyzing parameters of cooling fan system including relative location of fan and bellmouth,the interval between fan and bellmouth,the form of bellmouth and so on.Finally,the noise of engine decreased by about0.8dB(A) and noise from cooling fan system decreased by about1dB(A) after putting the above optimized implementation into the system.