The effective identification and control of powertrain structure borne harmonic noise is one key for achieving the desired noise pattern in a vehicle. Much work is being done in this field to refine and develop transfer path analysis techniques suitable for application at each stage of a vehicle development program.
For vehicle application, transfer path analysis and source identification techniques are in use today with varying degrees of success and application complexity. Investigation tools which are fast, do not require extensive vehicle dismantling and yet provide reliable answers, are of great value to NVH and sound quality engineers.
A novel Active Path Tracking (APT) method has been developed which is fast to apply and offers immediate practical confirmation of the contributions of all identified chassis transmission paths to the vehicle interior. Powertrain mount input forces are derived and their relative importance is ranked based upon their ability to recreate the vehicle interior sound field under investigation.
The method involves the novel adaptation of active noise cancellation techniques for identifying all sources and transmission paths as well as for the immediate verification of the results by active vibration cancellation procedures.
In this paper the method itself and its application for the interior noise improvement of a passenger car will be demonstrated.