| 摘要 |
PROBLEM TO BE SOLVED: To enhance silentness by effectively reducing noises caused in the interior of a vehicle by engine vibration. SOLUTION: An exhaust pressure introduction pipe 11 is branched and connected to the exhaust pipe 4 of an engine 3 and an actuator 12 for supplying exhaust pressure into a pressure introduction space S as the pulsating pressure of air is disposed in a portion of the exhaust pressure introduction pipe 11. The pressure introduction space S is defined between the roof 5 of a vehicle body 1 and a roof panel 13 (vibrating plate) disposed therebelow, and the exhaust pressure introduction pipe 11 is connected to the pressure introduction space S. The drive of the actuator 12 is controlled so that a detection signal from a first vibration detecting means 17 for detecting the vibration of the floor part 2a of the vehicle interior 2 and a detection signal from a second vibration detecting means 18 for detecting the vibration of the roof panel 13 are of the same phase, so that a sound wave from the floor part 2a and a sound wave from the roof panel 13 are opposite in phase and cancel out each other.
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