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:
Jun. 22, 1999
Filed:
Feb. 18, 1997
Ulrich Bahr, Brunswick, DE;
Michael Daetz, Tiddische, DE;
Daimler-Benz Aktiengesellschaft, Stuttgart, DE;
Volkswagen AG, Wolfsburg, DE;
Abstract
An ion current in the combustion chamber of an internal combustion engine is measured by using the spark plug as an ion current sensor. The ignition circuit arrangement has an ignition coil or transformer with a primary winding forming a primary circuit and a secondary winding forming a secondary circuit in which the spark plug is connected. A measuring voltage is applied to the secondary circuit by circuit components forming a measuring circuit for measuring the ion current. The measuring circuit provides a measuring voltage at a value that is lower than the battery voltage of the ignition system or corresponds to the battery voltage at most. A rectifying element is connected to the secondary circuit which feeds the secondary or ignition current into the battery circuit of the ignition system while an ion current caused to flow by the measuring voltage applied to the secondary circuit is measured between sparking times when no ignition current is flowing.