The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 27, 2011
Filed:
Apr. 14, 2009
Uwe Kassner, Moeglingen, DE;
Uwe Kassner, Moeglingen, DE;
Robert Bosch GmbH, Stuttgart, DE;
Abstract
The invention relates to an active noise cancellation device. The invention proposes a device and a method used to cancel the noise in an exhaust gas channel of a vehicle A noise signal is received form the exhaust gas channel, using a sound sensor, a frequency signal which has same amplitude as of noise signal but opposite phase, is generated, the generated frequency signal is acoustically mixed with the noise signal in the exhaust gas channel, using a sound converter, there by reducing the noise in the exhaust gas channel. The device also takes into account the reflection of the sound caused by an obstacle near the exhaust gas channel. A distance measuring device which is external to the active noise cancellation device provides the information about the distance between the obstacle and the exhaust gas channel. Based on the distance, the frequency signal is suitably modified to reduce the effect of sound reflections caused by the obstacle.