| 摘要 |
PURPOSE:To shut off a low frequency noise from an engine room by providing a means of forming an air layer on the engine room side surface of a panel, and increasing or reducing the thickness of said air layer based on the frequency of the noise of an engine room. CONSTITUTION:A control signal outputted from a controller 10 is varied in accordance with the noise frequency of an engine room 2 detected by a noise sensor 9, to control actuators 6. Thereupon, the actuators 6 make an air layer forming means 7 brought into contact with or separated from a floor panel 5, to vary the thickness L of an air layer 8. Thereby, the thickness L of the air layer 8 can be increasingly/reducingly controlled in accordance with the frequency of the noise of the engine room 2. Accordingly, a low frequency noise entering from the engine room 2 into an automobile room 4 can be effectively damped irrespective of the number of revolutions of the engine 1. |
