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:
Mar. 17, 1998
Filed:
Dec. 12, 1995
Noriaki Kondo, Kasugai, JP;
Hiroshi Inagaki, Komaki, JP;
NGK Spark Plug Co., Ltd., Nagoya, JP;
Abstract
A misfire detecting device for a multi-cylinder internal combustion engine is provided. The misfire detecting device comprises high voltage pulse producing means for producing, after spark discharge of a spark plug, a high voltage pulse which is not so high as to cause the spark plug to discharge, voltage applying means for applying the high voltage pulse to a conductive path connecting between the secondary winding of the ignition coil to the spark plug, by way of a reverse current preventing diode and a leakage preventing diode for preventing intrusion of the high voltage for ignition, voltage dividing means for dividing a voltage at the junction between the reverse current preventing diode and the leakage preventing diode to obtain a divided voltage thereat, and misfire detecting means for detecting a misfire on the basis of a decay characteristic of the divided voltage obtained after application of the high voltage pulse. The high voltage pulse producing means, the voltage applying means, the voltage dividing means and the combustion condition detecting means are housed within a case having a pair of terminals connectable directly and in series to the conductive path and having disposed therewithin a conductive line connecting between the terminals. The voltage applying means applies the high voltage pulse to the conductive line.