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-surface gap spark gap is formed between the earth electrode and the electrically conductive element or the slot.

A pre-chamber spark plug for a combustion chamber of an internal combustion engine has a pre-chamber which has a plurality of openings and which is fluidically connectable to the combustion chamber via the openings. Two spark gaps are arranged in the pre-chamber via which respective sparks can be formed. The spark gaps are arranged symmetrically distributed in the pre-chamber and a first of the spark gaps is arranged further outwards than the second spark gap along a direction extending perpendicularly to the longitudinal direction of the pre-chamber spark plug.

A spark plug includes a metal body member formed of a metal material, an insulating body member provided inside the metal body member and formed of an insulating material, a pair of central electrodes provided inside the insulating body member and having different polarities, and a ground electrode extending from the metal body member between a pair of central electrodes.

A spark plug includes a central electrode member and an outer electrode member. The central electrode member includes a central base and a plurality of electrode prongs extending in an axial direction from the central base. The outer electrode member surrounds the central electrode member. The outer electrode member includes a wall that is radially spaced from the plurality of electrode prongs to allow a series of electric arcs to form between the wall and the plurality of electrode prongs. The outer electrode member and the central electrode member are sized and positioned relative to one another such that a first rate of wear of the outer electrode member, along a longitudinal axis of the spark plug, is substantially equal to a second rate of wear of the central electrode member along the longitudinal axis.

A spark plug includes a central electrode member and an outer electrode member. The central electrode member includes a central base and a plurality of electrode prongs extending in an axial direction from the central base. The outer electrode member surrounds the central electrode member. The outer electrode member includes a wall that is radially spaced from the plurality of electrode prongs to allow a series of electric arcs to form between the wall and the plurality of electrode prongs. The outer electrode member and the central electrode member are sized and positioned relative to one another such that a first rate of wear of the outer electrode member, along a longitudinal axis of the spark plug, is substantially equal to a second rate of wear of the central electrode member along the longitudinal axis.

A spark plug including a terminal end, a firing end, an axial centerline extending between the terminal end and the firing end, and an insulative core extending between the terminal end and the firing end. The insulative core includes a central bore coincident with the axial centerline extending through the insulative core, and an insulative nose extending along and symmetrically about the axial centerline from an end surface of the insulative core at the firing end to a transition location along an axial length of the insulative core, wherein a perimeter surface of the insulative nose has a concave curvilinear shape between the end surface and the transition location.

A multipoint spark plug includes side electrodes provided in a pair so as to extend in a lengthwise direction of a tip end portion via a gap, and an intermediate electrode provided in the gap between the pair of side electrodes such that a plurality of ignition gaps are formed in the lengthwise direction of the tip end portion. An electrode holding portion is formed from separate parts that hold the side electrodes and the intermediate electrode, respectively, so as to insulate the side electrodes and the intermediate electrode from the main body portion, and the respective parts thereof project into the combustion chamber from the tip end portion.

A dual spark plug may include: a metal body made of metal material, an insulating body provided inside of the metal body and made of an insulating material, a pair of central electrodes provided inside of the insulating body and electrically connected with an ignition coil, and a pair of ground electrodes respectively extended from both ends the metal body, and spaced apart from ends of the pair of central electrodes by a predetermined distance.

A dual spark plug may include: a metal body made of metal material, an insulating body provided inside of the metal body and made of an insulating material, a pair of central electrodes provided inside of the insulating body and electrically connected with an ignition coil, and a pair of ground electrodes respectively extended from both ends the metal body, and spaced apart from ends of the pair of central electrodes by a predetermined distance.