Ignition coil for use in engine and engine having plastic cylinder head cover

In an individual ignition type ignition coil for use in an engine in which a center core, a secondary coil wound on a secondary bobbin and a primary coil wound on a primary bobbin are installed concentrically from an inner side of a coil case in order, and said ignition coil is connected directly to a respective spark plug of said engine, the ignition coil for use in the engine characterized in that

• an insulation resin is filled up between said secondary bobbin and said center core;
• in said secondary bobbin, a secondary coil low voltage side is a potting side of said insulation resin;
• said secondary bobbin has an inclination with a difference in inner diameter of said secondary bobbin in such a manner in which an inner diameter of said secondary bobbin is formed large at said secondary coil high voltage side and is formed small toward for a secondary coil high voltage side;
• and
• said secondary bobbin forms a bobbin structure in which a thickness of said secondary bobbin is formed thin at said secondary coil low voltage side and is formed thick toward for said secondary coil high voltage side.

In an individual ignition type ignition coil for use in an engine in which a center core, a secondary coil wound on a secondary bobbin and a primary coil wound on a primary bobbin are installed concentrically from an inner side of a coil case in order, at upper portion of said coil case a circuit case having a connector is installed inside an ignition unit of the ignition coil, and said ignition coil is connected directly to a respective spark plug of said engine, the ignition coil for use in the engine characterized in that

• an insulation resin is filled up between said secondary bobbin and said center core;
• at an upper end opening of said secondary bobbin said insulation resin is carried out a compression molding and a dent is formed at said upper end opening of said secondary bobbin;
• in said circuit case having said connector, a bottom portion of said circuit case is communicated to an upper portion of said coil case;
• a molding resin is filled up extending over from an interior portion of said circuit case having said connector to said secondary coil and said primary bobbin of said coil case and between said primary coil to said coil case;
• and
• said dent formed on said insulation resin is buried by said epoxy resin.

In an individual ignition type ignition coil for use in an engine in which a center core, a secondary coil wound on a secondary bobbin and a primary coil wound on a primary bobbin are installed concentrically from an inner side of a coil case in order, at upper portion of said coil case a circuit case having a connector is installed inside an ignition unit of the ignition coil, and said ignition coil is connected directly to a respective spark plug of said engine, the ignition coil for use in the engine characterized in that

• an insulation resin is filled up between said secondary bobbin and said center core;
• at an upper end opening of said secondary bobbin said insulation resin is carried out a compression molding and a hemisphere dent is formed at said upper end opening of said secondary bobbin;
• in said circuit case having said connector, a bottom portion of said circuit case is communicated to an upper portion of said coil case;
• an epoxy resin is filled up extending over between from an interior portion of said circuit case having said connector to said secondary coil and said primary bobbin of said coil case and between said primary coil to said coil case;
• and
• said hemisphere dent formed on said insulation resin is buried by said molding resin.

An engine having a plastic head cover, characterized in that

• a cylinder head of the engine is covered by a plastic head cover;
• a respective spark plug mounted in said cylinder head is connected directly to an individual ignition type ignition coil which is prepared for each of said spark plug;
• said individual ignition type ignition coil comprises a coil portion in which a center core, a secondary coil wound on a secondary bobbin and a primary coil wound on a primary bobbin are installed concentrically inside a thin narrow cylindrical shape coil case and a circuit case having a connector which is provided at an upper portion of said coil case and has an ignition circuit unit inside;
• said coil portion is penetrated through said plastic head cover and the center of gravity of said ignition coil is positioned at a lower position from said plastic head cover;
• and
• said circuit case having said connector is fixed to an outer face of said plastic head cover.