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:
Aug. 29, 1995
Filed:
Dec. 13, 1993
Katsuyuki Tanaka, Nukata, JP;
Masanori Kato, Seto, JP;
Kouzi Ohara, Nukata, JP;
Tokio Kohama, Nishio, JP;
Yoshitaka Nishio, Nagoya, JP;
Nippondenso Co., Ltd., Kariya, JP;
Abstract
A device for cancelling annoying sounds caused by operation of an internal combustion engine. An intake sound of the engine, and also a rotational speed of the engine, are obtained. The phase difference between the present intake sound and a desired intake sound is obtained using map data. The map data depends on the rotational speed of the engine and is specifically calculated so that at least the (n+0.5) harmonics (n integer.gtoreq.0) are cancelled. The phase data is used to drive a ceramic speaker or two oppositely directed ceramic speakers, to appropriately compensate the input sound.