| 摘要 |
PURPOSE:To allow the generated interference sound wave and the suction sound wave generated at the suction port to interact and cancel with each other and effectively reduce suction noise without response delay by providing a sound wave interferer radiating the interference sound wave to the suction port and driving it. CONSTITUTION:A sound wave interferer 4 such as a well-known speaker is fitted on the suction port 3 side of a suction pipe 2 fitted to an engine 1. A synchronous oscillator 10 inputted with the output signal of a rotating speed sensor 9 is provided, the sine wave signal for the reference frequency is generated, and the signal is inputted to multiple frequency controllers 12. Sine waves with the frequency integer times the reference frequency are generated by these frequency controllers 12, and amplitude values of the generated sine wave signals are adjusted by gain controllers 13. Phase values of the integer-multiplied sine waves generated by the frequency controllers 12 are shifted by phase position shifters 14. Outputs of the phase shifters 14 are added in an adder 17, and the sound wave interferer 4 is controlled by its output via a power amplifier 7. |
