Abstract: An exhaust aftertreatment system, including injection of chemical species, includes a mixer provided by a spiral chamber.

Abstract: An exhaust emission control regeneration system regenerates a particulate filter by combusting trapped particulate and producing a combustion product from such combustion, and uses the combustion product to assist regeneration of a downstream catalyst, such as CO assisting regeneration of a downstream NOX adsorber, located in sufficiently close proximity to a diesel particulate filter.

Abstract: An exhaust aftertreatment device (10) includes an aftertreatment element (24) for treating internal combustion engine exhaust, an injector (26) for injecting chemical species mixing with the exhaust prior to reaching the aftertreatment element, and a turbulator (36) turbulating the exhaust to enhance the noted mixing. In a desired combination, a two-stage integrated perforated tube combination structure includes a turbulent mixing tube (38) disposed in an acoustic tube (40) and concentrically surrounded thereby.

Abstract: An exhaust aftertreatment device (10) includes an aftertreatment element (24) for treating internal combustion engine exhaust, an injector (26) for injecting chemical species mixing with the exhaust prior to reaching the aftertreatment element, and a turbulator (36) turbulating the exhaust to enhance the noted mixing. In a desired combination, a two-stage integrated perforated tube combination structure includes a turbulent mixing tube (38) disposed in an acoustic tube (40) and concentrically surrounded thereby.

Abstract: An active silencer for a vehicle exhaust system that is constructed so that it can be hung underneath the vehicle without altering the vehicle. The silencer has a chamber isolated from the exhaust flow. A duct spans longitudinally through the chamber. One or more loudspeakers (e.g. 2 or 4 loudspeakers) are mounted on the duct side-by-side. The loudspeakers share a common tuning volume within the duct which is ported to a mixing apparatus where the canceling acoustic wave mixes with noise from the exhaust flow before the exhaust noise exits to the atmosphere.

Abstract: A multi-channel communication system is provided. In an active acoustic attenuation implementation, noise, including cross-coupled noise between channels and locations, designated audio signals, and echoes, are canceled, but not speech from another location. A particularly desirable vehicle application is provided.

Abstract: An active acoustic attenuation system specifies the error signal (44) to correspondingly specify the output acoustic wave. In the preferred embodiment, the error signal (44) is specified by summing (210) the error signal (44) with a desired signal (204) to provide a specified error signal (206) to the error input (202) of the adaptive filter model (40) such that the model (40) outputs the correction signal (46) to the output transducer (14) to introduce the canceling acoustic wave which specifies the output acoustic wave such that a desired signal is present in the output acoustic wave.

Abstract: Active acoustic attenuation apparatus is provided for cancellation of noise from an exhaust pipe (12). A chamber (50) has an input (70) receiving exhaust from the exhaust pipe and directing the exhaust along a flowpath (76) to a chamber output (74). Speakers (88, 90) are transversely spaced and offset from the flowpath and introduce sound into the chamber at a space (56) having a transverse area at least as large as each speaker, to minimize acoustic loading of the speakers and to protect the speakers from the heat of hot exhaust for automotive applications, including electronic mufflers.