An ignition apparatus includes a spark plug having a high voltage electrode and an external electrode facing each other across a gap and being configured to generate a spark discharge in the gap to ignite a combustible fuel mixture in a combustion chamber of an internal combustion engine, an ignition coil device configured to generate a predetermined high voltage and supply the high voltage to the high voltage electrode to form a path for the spark discharge in the gap, a high frequency power supply having a band-pass filter and being configured to supply an alternating current to the spark discharge path, and a control device configured to control operation timing of the high frequency power supply. The band-pass filter passes a frequency of from 1 MHz to 4 MHz.

An ignition coil is provided with a primary coil, a secondary coil, a center core, and an outer core. The primary coil, secondary coil, the center core, and the outer core are accommodated inside a case, the inside of the case is filled with a resin filler having electrical insulating properties. The case has an opening member which opens to an upper-side of a vertical direction, a side wall section formed by the opening member, and a bottom member covering a lower-side of the side wall section. A circular cover member, formed on the opening member, provided with a through opening which passes through the inner-side of the opening member in the vertical direction.

An ignition coil is provided with a primary coil, a secondary coil, a center core, and an outer core. The primary coil, secondary coil, the center core, and the outer core are accommodated inside a case, the inside of the case is filled with a resin filler having electrical insulating properties. The case has an opening member which opens to an upper-side of a vertical direction, a side wall section formed by the opening member, and a bottom member covering a lower-side of the side wall section. A circular cover member, formed on the opening member, provided with a through opening which passes through the inner-side of the opening member in the vertical direction.

An ignition system includes an ignition coil with a primary winding and a secondary winding having a terminal for providing a high voltage (HV). An electrode arrangement of an igniter includes first and second HV electrodes coupled to the terminal of the secondary winding. The igniter also has at least one ground electrode. A first spark gap is defined between the first HV electrode and the at least one ground electrode, and a second spark gap is defined between the second HV electrode and the at least one ground electrode. A first capacitor is disposed in-line between the first HV electrode and the terminal of the secondary winding and a second capacitor disposed in-line between the second HV electrode and the terminal of the secondary winding of the ignition coil. The ignition system includes a driver module coupled to a terminal of the primary winding, for driving the ignition coil.

A noise-preventing resistor has a structure in which a resistance wire is wound around an outer circumferential surface of a core, cap terminals are attached to either end part of the core, and part of an insulative coating (resin coating) covering the resistance wire and part of the resistance wire positioned underneath the insulative coating are cut, forming peeled regions exposing the resistance wire. As a result, conduction between the cap terminals and the resistance wire in the noise-preventing resistor is ensured.

An ignition device includes a case having an opening and a bottom wall, a coil bobbin arranged in the case having a through hole, a first end and a second end, an ignition coil wound around the coil bobbin, a core made of magnetic material and projecting from the opening and from the bottom wall, and extending through the coil bobbin, a retainer having a ring portion and multiple leg portions extending from the ring, and a filling resin in the case. The core extends through the ring portion and the leg portions extend in between an inner surface of the coil bobbin and an outer peripheral surface of the core toward the bottom wall, and the case is filled with the filling resin in a manner that at least a part of the ring portion is not covered by the resin.

A noise-preventing resistor has a structure in which a resistance wire is wound around an outer circumferential surface of a core, cap terminals are attached to either end part of the core, and part of an insulative coating (resin coating) covering the resistance wire and part of the resistance wire positioned underneath the insulative coating are cut, forming peeled regions exposing the resistance wire. As a result, conduction between the cap terminals and the resistance wire in the noise-preventing resistor is ensured.

A first filler resin is disposed to cover at least an outer peripheral side of a secondary spool and a secondary coil. The second filler resin is filled inside a case and seals a cover sealant which includes a primary coil, secondary spool, a secondary coil, a center core, an outer core and the first filler resin. The connector protrudes to an outside of the case. The case has a fixing portion. The second filler resin has a lower elasticity than the first filler resin. The ignition coil is manufactured by filling the first resin inside the case, and filling the second resin after the first resin is cured.

A first filler resin is disposed to cover at least an outer peripheral side of a secondary spool and a secondary coil. The second filler resin is filled inside a case and seals a cover sealant which includes a primary coil, secondary spool, a secondary coil, a center core, an outer core and the first filler resin. The connector protrudes to an outside of the case. The case has a fixing portion. The second filler resin has a lower elasticity than the first filler resin. The ignition coil is manufactured by filling the first resin inside the case, and filling the second resin after the first resin is cured.

A spark plug adapter device for an internal combustion engine, comprising a first housing having a central bore configured to engage with an electrical harness at a proximal end and having an external thread formed at a distal end. The spark plug adapter device further comprising a second housing having a central bore and an internal thread provided at a proximal end thereof to mate with the external thread formed on the distal end of the first housing and an external thread formed at a distal end to facilitate mating with the internal combustion engine. Moreover, the first housing and the second housing may engage to define an internal space into which a spark plug is received, such that the first and second housings encapsulate the spark plug.