Patent attributes
The rotation of an ignition coil apparatus upon mounting thereof on an internal combustion engine is prevented with a simple structure, and the efficiency of mounting the ignition coil apparatus on the internal combustion engine is improved. A high voltage tower is formed integrally with a case main body having a transformer received therein, and holds a high voltage output terminal therein. A cylindrical plug boot has its one end attached to the high voltage tower. The plug boot is inserted into a plug hole in an internal combustion engine main body whereby the ignition coil apparatus is mounted on the internal combustion engine main body through a head cover having upstanding wall portions. A pair of protrusions for restricting the rotation of the casing main body around an axis of the plug hole are formed on a surface of the casing main body in opposition to the wall portions.
