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:
May. 08, 1979
Filed:
Jan. 27, 1978
Bernd W Kalkhof, Reutlingen, DE;
Robert Bosch GmbH, Stuttgart, DE;
Abstract
The voltage in the secondary of an ignition coil is prevented from reaching an amplitude at which a spark might be created by a Zener diode connected in parallel with the series transistor acting as a switch which interrupts the current through the primary winding of the coil. Upon breakdown of the Zener diode, the series transistor is switched to the conductive state briefly, thereby preventing further voltage build-up in the secondary. When the engine is in operation, a transistor which forms part of a voltage divider is switched to the conductive state, connecting the voltage divider between the secondary winding and the Zener diode. The voltage divider is so dimensioned that the Zener diode will respond to a voltage slightly less than the breakdown voltage of the emitter-collector circuit of the series transistor, but higher than the voltage required for creating a spark.