Patent ID: 7796004

Claim:
An ignition coil of a dual ignition type comprising: a coil case; a coil assembly housed in said coil case; and a casting material configured to fill a gap between said coil case and said coil assembly and gaps in said coil assembly, wherein said coil assembly has a coil pair comprising a primary coil and two secondary coils disposed concentrically with said primary coil, the two secondary coils of the coil pair being wound in opposite directions with a center of winding width of the two secondary coils with respect to the longitudinal direction of the primary coil defining a boundary, a center of winding width of the primary coil with respect to the longitudinal direction thereof being shifted from the boundary of the secondary coils by a predetermined width so as to balance outputs from the two secondary coils, an output end of one of the two secondary coils being directly connected to a first ignition plug arranged in a first cylinder, and an output end of the other of the two secondary coils being connected via a high tension cord to a second ignition plug arranged in the first cylinder, and the center of winding width of the primary coil, with respect to the longitudinal direction of the primary coil, being shifted by the predetermined width toward the secondary coil connected to the second ignition plug, wherein the shifting width is 1.5 mm to 3.0 mm.