Vehicle Fuel Air Heater Noise Performance Study

The noise caused by vehicles is the chief source of noise in the city, which affects the people's life severely.As a heating equipment for coach in winter, the air fuel fired heater has been adopted largely, which inevitably causes some noise. To meet the need for the environment protection and the full comfort, some studies on how to reduce the noise seem to be very necessary to do. This will be dealt with in this paper.The discrimination for noise source from QN700 indicates: the fan noise(625Hz), the electromagnetism noise(962Hz) and the burning noise are the main noise sources. Then, some proposals and methods are brought forward on the analysis of the causes of these kinds of noise.Seeing that the noise radiates through the inlet of air and iron box, a silencer for the inlet and a rectangular enclosure are designed. The results of the experiments indicate: the measures are very effective to have the noise pressure level of band reduced, especially in the 1000Hz where it is decreased by 4.1dB, and the same is to reduce the noise level from the inlet of air. Therefore, the measures can be considered successful.Through the study, the noise of QN700 air fuel fired heaters is solved radically, and the route is offered to settle the noise control of this type of equipment.