| 摘要 |
PURPOSE: A low-frequency performance tester of a muffler for a vehicle is provided to predict performance of a muffler by testing the low frequency of the muffler influencing idle booming noise of a vehicle without mounting the muffler at the vehicle actually. CONSTITUTION: A low-frequency performance tester(20) of a muffler consists of a surge tank(22), a connecting pipe(24), a DC motor(26), a motor controller, a noise analyzer(30), an amplifier(32), an air compressor(34) and an RPM(Revolutions Per Minute) sensor. Compressed air flows into the surge tank of an engine(40) by the air compressor, and the DC motor is driven at necessary RPM through the DC motor controller. The air flows into a cylinder of the engine through an intake valve to be compressed by a rising piston. Then a large pressure change is formed at a discharge port when an exhaust valve is opened. The air is discharged through the exhaust system. Herein, the exhaust system for test is mounted at the engine and noise pressure changes are measured through microphones(46,48). The signal is analyzed in frequency. Therefore, performance of a muffler(44) is estimated.
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