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:
Jul. 27, 1993
Filed:
Apr. 24, 1991
Hitachi, Ltd., Tokyo, JP;
Abstract
A method and apparatus of detecting knocking in an internal combustion engine having a crankshaft uses a knock detecting sensor to detect vibration caused by knocking. The signals from the knock detecting sensor are detected between a first and a second moment of time (i.e. a measurement window) and at least one of the first and second moments of time are independently varied in dependence upon a vibration spectrum of frequencies to be detected. In a preferred embodiment a plurality of frequency spectra, each having a different first and second moment of time, are each separately analyzed for determining knock intensity. The moments of time are represented by first and second angles of the crankshaft. A plurality of measurement windows are advantageously used to determine the level of knocking and if the level exceeds a predetermined level the ignition timing for the engine is retarded. The frequency of maximum amplitude is arranged in operation to be the center frequency of a frequency spectrum determined by the measurement window.