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:
Aug. 29, 1989
Filed:
Aug. 25, 1988
Sten Jiewertz, Jarna, SE;
Saab-Scania AB, , SE;
Abstract
The invention relates to a method and an arrangement for detecting ionizing current in an ignition circuit incorporated in the ignition system of an internal combustion engine, in which a measuring voltage is applied to the ignition circuit in at least one secondary winding, and in which a measuring device is used to detect the possible presence of an ionizing current in the ignition circuit. A low measuring voltage is applied during an engine start sequence, or alternatively, no measuring voltage at all, and a high measuring voltage is applied subsequent to the engine start. The invention thereby overcomes the problem existing when measuring ionizing currents of the spark plugs becoming coated with soot deposits as a result of the electrical voltage field which always exists between the electrodes of respective plugs. Such problem is particularly troublesome during an engine start sequence, since the deposits can prevent the engine from starting.