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:
Apr. 24, 2001
Filed:
Jan. 28, 1999
NGK Spark Plug Co., Ltd., Nagoya, JP;
Abstract
An ion current detection apparatus which can detect ion current with a high degree of accuracy regardless of the presence of voltage damped oscillation and which does not cause contamination of a spark plug. A spark discharge current Isp generated upon spark discharge of a spark plug,flows through a charge diode,a capacitor,and a diode,which form a closed loop together with the spark plug,and a secondary winding L,of an ignition coil,that constitutes an ignition apparatus. As a result, a Zener diode,connected in parallel to these components generates a Zener voltage Vz and thereby charges the capacitor,When a preset wait time has elapsed after the ignition timing for starting spark discharge, the discharge switch,short-circuits the opposite ends of the charge diode,to discharge the capacitor,so that a high voltage having a polarity opposite that in the case of spark discharge is applied to the spark plug. An ion current Iio flowing at this time is detected by use of a resistor,connected in parallel to the diode