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. 14, 1991
Filed:
Aug. 10, 1989
Albert A Skinner, Anderson, IN (US);
Ronnalee House, Anderson, IN (US);
Roger W Kellams, Carmel, IN (US);
Jose A Cruz, Chesterfield, IN (US);
General Motors Corporation, Detroit, MI (US);
Abstract
An ignition coil for developing spark plug firing voltages. The magnetic current for the coil comprises an axially extending core that joins axially spaced annular parts. The core and parts can be formed of iron particles in a binder of electrical insulating material. A primary winding is disposed about the core and a secondary winding is disposed about the primary winding. An axially extending circular part that is formed of magnetic material is positioned to provide air gaps with outer surfaces of said annular parts. The circular part forms a shield that increases the capacitance of the secondary winding. The total stored magnetic energy does not vary substantially with variations in air gap length. The cross-sectional area A of the air gap is large as compared to the length L of the air gap so that the ratio A/L does not vary much with variations in L.