An ignition coil includes a coil unit, a hollow cylindrical joint, and a spring. The joint couples the coil unit with a spark plug. The spring is inserted into a through-hole in the joint to electrically connect the coil unit and the spark plug together. The joint has electrical insulation and rubber elasticity. The spring includes a spring base section, a spring head section, and a spring intermediate section lying between the spring base and head sections. The joint has an inner peripheral surface placed in direct contact with the spring intermediate section in a radial direction of the joint. The spring intermediate section is wound more densely than each of the spring base section and the spring head section in a condition where the spring is subjected to no load. This structure serves to minimize a risk of generation of a corona discharge in the ignition coil and an ignition device equipped with the ignition coil and improve the productivity thereof.

An ignition coil includes a primary coil, a secondary coil, a center core, an outer core, an igniter, a coil case and an electrically-insulative fixation resin. On an interior surface of the coil case on a bottom part side in a mounting direction, there is formed a case-side rib to protrude from the interior surface of the coil case to a high-voltage side in an axial direction. The case-side rib has a taper shape such that the protruding amount of the case-side rib to the high-voltage side in the axial direction increases in the mounting direction toward the bottom part side. The case-side rib is arranged to abut a corner portion of the igniter on the bottom part side in the mounting direction and on a low-voltage side in the axial direction and thereby press the igniter against the outer core.

An ignition coil includes a primary coil, a secondary coil, a center core, an outer core, an igniter, a coil case and an electrically-insulative fixation resin. On an interior surface of the coil case on a bottom part side in a mounting direction, there is formed a case-side rib to protrude from the interior surface of the coil case to a high-voltage side in an axial direction. The case-side rib has a taper shape such that the protruding amount of the case-side rib to the high-voltage side in the axial direction increases in the mounting direction toward the bottom part side. The case-side rib is arranged to abut a corner portion of the igniter on the bottom part side in the mounting direction and on a low-voltage side in the axial direction and thereby press the igniter against the outer core.

A passive prechamber spark plug for use in a combustion chamber of a vehicle engine includes an upper prechamber having an upper opening where the upper prechamber is connectable to the combustion chamber via the upper opening. An air ignition spark is formable via an upper air spark gap. A central electrode is disposed in an upper region of the upper prechamber where a base of the upper prechamber opposite the upper region is an insulator. An electrically conductive element or a slot is guided by the insulator continuously from the upper prechamber into a lower region under the base and the lower region is either a lower prechamber or is arrangeable directly in the combustion chamber. An earth electrode is disposed in the lower region such that a lower air spark gap is formed between the earth electrode and the electrically conductive element or the slot.

A passive prechamber spark plug for use in a combustion chamber of a vehicle engine includes an upper prechamber having an upper opening where the upper prechamber is connectable to the combustion chamber via the upper opening. An air ignition spark is formable via an upper air spark gap. A central electrode is disposed in an upper region of the upper prechamber where a base of the upper prechamber opposite the upper region is an insulator. An electrically conductive element or a slot is guided by the insulator continuously from the upper prechamber into a lower region under the base and the lower region is either a lower prechamber or is arrangeable directly in the combustion chamber. An earth electrode is disposed in the lower region such that a lower air spark gap is formed between the earth electrode and the electrically conductive element or the slot.

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.

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.

An ignition coil for an internal combustion engine includes a primary bobbin including a winding cylinder part and a connection part between the winding cylinder part and a connector part, a primary coil including a primary main coil and a primary sub coil, and a secondary coil. When one of the primary main coil and the primary sub coil that includes an innermost coil part around the winding cylinder part is defined as a firstly-wound coil and the other is defined as a secondly-wound coil, firstly-wound ends, which are ends of the firstly-wound coil, and secondly-wound ends, which are ends of the secondly-wound coil, are attached to the connection part, and a shortest distance from a central axis of the winding cylinder part to each of the firstly-wound ends is smaller than a shortest distance from the central axis of the winding cylinder part to each of the secondly-wound ends.

An ignition coil for an internal combustion engine includes a primary bobbin including a winding cylinder part and a connection part between the winding cylinder part and a connector part, a primary coil including a primary main coil and a primary sub coil, and a secondary coil. When one of the primary main coil and the primary sub coil that includes an innermost coil part around the winding cylinder part is defined as a firstly-wound coil and the other is defined as a secondly-wound coil, firstly-wound ends, which are ends of the firstly-wound coil, and secondly-wound ends, which are ends of the secondly-wound coil, are attached to the connection part, and a shortest distance from a central axis of the winding cylinder part to each of the firstly-wound ends is smaller than a shortest distance from the central axis of the winding cylinder part to each of the secondly-wound ends.

A battery pack for use in providing starting power for a starter motor of an internal combustion engine and to supply power to one or more auxiliary loads. The battery pack includes an outer housing that encloses a plurality of battery cells. The battery pack further includes a control module. The control module includes a processing circuit configured to control one or more functions associated with the internal combustion engine and an interface circuit configured to interface with the internal combustion engine.