Abstract
The noise generating mechanism of reciprocating air compressor for heavy duty vehicles at idling was analyzed. It was realized that the gear rattling noise of the engine gear train caused by the negative value of the air compressor drive torque was a major noise source. For reducing the gear rattling noise, a loading apparatus with an air cylinder that cancels the negative value of the air compressor drive torque was newly made. As the gear rattling disappeared when the loading apparatus operated, the impulsive sound level was reduced about 10dB(A).
