Abstract: An adaptive noise control system is deployed in a box-like structure positioned within the transfer path along which the noise is being transmitted from the source of the generated noise to the receiver of the noise in the passenger compartment of an automobile. The adaptive noise control system is can be deployed in the dual bulkhead of the vehicle dashboard to provide a constrained volume within which engine noise can be controlled. The adaptive control system generates a mathematical model of the noise to be controlled in response to the acoustic environment identified by sensors placed within the engine compartment. Sensors in the passenger compartment define the effectiveness of the noise control system. The controller is operable to update the mathematical model in response to the changes in the acoustic environment, thus providing the appropriate acoustic response within the dual bulkhead plenum for control of noise along the transfer path.

Abstract: A noise control system is directed to the path along which the noise is transmitted from the source of the noise being generated to the receiver of the noise in the passenger compartment of an automotive vehicle. The noise control system is deployed in a box structure, such as the dual bulkhead of the dashboard of the vehicle, to provide a constrained volume within which engine noise can be controlled. The dual bulkhead plenum houses an active noise control apparatus, such as a speaker or a vibrating device, between the bulkheads to be operable with a control algorithm to generate sound that can control the noise or vibrations generated by the engine. The plenum can also be treated with passive noise control materials, such as viscoelastic damping materials, acoustical foam or heavy vinyl barrier and foam to block airborne sound and vibrations, in addition to the active noise control.

Abstract: A noise control system operable within a box-like structure provided by the dual bulkhead plenum of the vehicle dashboard positioned within the transfer path along which the noise is being transmitted from the source of the generated noise to the receiver of the noise in the passenger compartment of an automobile. The plenum is divided into discrete chambers into each of which is provided smart materials affixed to the walls of the plenum to be operable for selectively changing a property characteristic of the chambers to vary the acoustic resonance of the plenum and change the effectiveness of controlling the transmission of noise energy therethrough. A controller is coupled to the smart materials to change said property characteristic of the smart material in response to noise cancellation requirements.

Abstract: A noise control system is operable within a box-like structure provided by the dual bulkhead plenum of the vehicle dashboard positioned within the transfer path along which the noise is being transmitted from the source of the generated noise to the receiver of the noise in the passenger compartment of an automobile. The plenum is divided into discrete chambers into each of which is provided a counter noise generating apparatus to create a counteracting noise offsetting the noise generated at the source. The acoustic resonance of the chambers amplifies the noise control energy. The geometry of the individual chambers can be varied to optimize the packaging and sound control or shaping strategy. The sound energy permitted to pass through the plenum to the driver's side of the passenger compartment can be tuned to be different than the noise received in the passenger's side.

Abstract: An arm assembly for an automotive engine accessory drive belt tensioner has a wound spring which is permanently captured upon the arm by a retainer which is effective not only prior to installation of the arm upon an engine, but also after the installation and removal of the arm from an engine.