Patent attributes
An ignition coil is constructed of a center core, a primary coil, a secondary coil, and an outer circumferential core. The center core and the outer circumferential core are connected with each other via a first magnetoresistive member on one axial end side. The center core and the outer circumferential core are connected with each other via a second magnetoresistive member on the other axial end side. A permanent magnet is arranged in an axially central portion of the center core. A magnetic passage is formed of the center core, the permanent magnet, the first magnetoresistive member, the outer circumferential core, and the second magnetoresistive member. Magnetic flux generated by the primary coil is reduced through the first and second magnetoresistive members, and is reverse-biased by the permanent magnet.
