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. 13, 1994
Filed:
Jul. 16, 1992
Hitachi, Ltd., Tokyo, JP;
Abstract
A knock detection device being provided with a plurality of digital filter units, each is designed to cover respective characteristic resonance vibration frequency components inherent to resonance vibration modes due to knocking and including first, second and third digital filters, the first digital filter being tuned to the center frequency of the characteristic resonance vibration frequency component, the second digital filter being tuned to a neighboring lower frequency and the third digital filter being tuned to a neighboring higher frequency. The maximum intensity among the three intensities determined by the first, second and third digital filters is determined as the intensity for the characteristic resonance vibration frequency component and the determined result is fed-back to the digital filter unit to correct the center frequency of the first digital filter to the frequency showing the maximum intensity, whereby the knocking is reliably detected without being affected by such factors as engine operating conditions and secular changes of the engine.