| 摘要 |
PURPOSE: Dynamic exhaust system installation structure for prevention of a booming noise is provided to improve the booming noise following a change of RPM(Revolutions Per Minute) of an engine by a frequency band and reduce the room noise of a vehicle following a change of a dynamic characteristic of an exhaust system. CONSTITUTION: In dynamic exhaust system installation structure for prevention of a booming noise, a dynamic plate(30), vertically vibrating according to a change of the RPM of an engine, is installed between a vehicle body(10) and an exhaust system(20). An LVDT(Linear Variable Differential Transformer,40) and a spring are installed between the dynamic plate and the vehicle body. The LVDT senses the vertical and horizontal and front and rear vibration of the exhaust system and the vertical vibration of the dynamic plate and outputs voltage of a predetermined level. The spring is filled with a magneto rheological fluid to reduce room noise following a change of a dynamic characteristic of the exhaust system, while having a spring coefficient reducing the booming noise caused by resonance of the exhaust system. An electromagnet(60), the voltage of which is varied to improve the booming noise following the change of the RPM of the engine according to vibration elements of the exhaust system, is installed to the periphery of the spring. The varying range of the voltage acting on the electromagnet is controlled from an electronic control unit(80). The electronic control unit decides the varying range of the voltage through data stored in a memory(81), on the basis of the frequency decided according to the RPM of the engine measured from a crank position sensor(70) and the voltage value output from the LVDT.
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