Truck Noise IV-B Identifying the Sources of Noise on a Heavy Duty,Diesel Truck.

摘要

Truck noise is a complex interaction of many noise sources which can be individually studied using a technique referred to as Noise Source Identification. During Source Identification,all known or suspected noise sources are artificially silenced except the one being studied. Using this technique,it was shown that the total vehicle noise of 88dB(A) was caused primarily by the cooling system noise (86dB(A)),the exhaust system noise (83dB(A)) and the engine (78dB(A)). Also identifiable were the intake system noise (74dB(A)),the transmission noise (71dB(A)) and all other noise sources (mostly tires at 64dB(A)). Generally,each of the noise sources reaches its maximum noise output at a different location during the drive-by test;in fact,different sources were predominant during different portions of the drive-by. In order to achieve the program goal of 78dB(A) for the overall truck with the use of an engine enclosure,it is necessary to reduce the noise level of each of the five major sources to approximately 71dB(A).