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:
Sep. 08, 1992
Filed:
Oct. 04, 1990
Donald P Pfaff, Mount Clemens, MI (US);
Nick S Kapsokavathis, Rochester, MI (US);
Natalie A Parks, Utica, MI (US);
General Motors Corporation, Detroit, MI (US);
Abstract
A method is described for attenuating the amplitudes of multiple harmonic noise components contained within noise generated by an internal combustion engine, based upon the rotation of the engine in its operating cycle. A signal representing selected multiple harmonic noise components is generated from a table of values, based upon the engine rotation. This signal is adaptively filtered to produce a canceling waveform, which is superimposed with the engine noise to attenuate the selected multiple noise harmonics. The method is useful for selecting and attenuating dominant noise harmonics produced at different engine speeds or by different types of engines, and the dominant harmonics of different forms of noise produced by the same engine.