Active Control of Automotive Air Induction Noise via Source Coupling 2001-01-1613

Engine noise emanating from the air intake of automotive induction systems can be effectively suppressed through active noise control. Source coupling is used as the active noise control strategy. A small woofer, co-axially mounted inside the fresh air duct, is located in the plane of the fresh air intake and acts as the secondary noise source. An error microphone is located near the air intake and a synchronous reference signal is provided by an engine tachometer signal. This active noise control system has been tested on several engines. The radiated engine noise from the induction system has been effectively eliminated over the control bandwidth. The power draw of the speaker is minimal and the flow restriction of the actively controlled inlet has been significantly reduced compared to the production air induction system.