A spark plug includes a terminal electrode extending in an axial direction of the spark plug. The terminal electrode has an end in the axial direction, and has a recess formed in the end of the terminal electrode. The recess has a bottom surface and an identifier on the bottom surface. The recess has a side surface parallel to the axial direction.

An igniter having at least two electrodes spaced from each other by an insulating member having a substantially continuous surface along a path between the electrodes. The electrodes extend substantially parallel to each other for a distance both above and below said surface. The insulating member has a channel (recess) for receiving at least a portion of a length of at least one of said electrodes below and to said surface of the insulating member. The surface of the insulating member may preferably be augmented with a conductivity enhancing agent. The insulating member and electrodes are configured so that an electric field between the electrodes at said surface does not have abrupt field intensity changes, whereby when a potential is applied to the electrodes sufficient to cause breakdown to occur between the electrodes, discharge occurs at said surface of the insulating member to define a plasma initiation region.

An igniter having at least two electrodes spaced from each other by an insulating member having a substantially continuous surface along a path between the electrodes. The electrodes extend substantially parallel to each other for a distance both above and below said surface. The insulating member has a channel (recess) for receiving at least a portion of a length of at least one of said electrodes below and to said surface of the insulating member. The surface of the insulating member may preferably be augmented with a conductivity enhancing agent. The insulating member and electrodes are configured so that an electric field between the electrodes at said surface does not have abrupt field intensity changes, whereby when a potential is applied to the electrodes sufficient to cause breakdown to occur between the electrodes, discharge occurs at said surface of the insulating member to define a plasma initiation region.

A spark plug for an internal combustion engine includes a cylindrical insulator, a center electrode, a cylindrical housing, and a plug cover. On a tip side of the insulator, an auxiliary combustion chamber is formed which is surrounded by at least the plug cover. The plug cover is provided with nozzle holes that communicate between the auxiliary combustion chamber and the outside of the auxiliary combustion chamber. A central axis of the nozzle hole is inclined with respect to a plug radial direction when viewed in a plug axial direction. At least a part around an outer opening of the nozzle hole is provided with a concave portion that is adjacent to the outer opening. The concave portion is recessed from the outside to the inside of the plug cover.

A spark plug for an internal combustion engine includes a cylindrical insulator, a center electrode, a cylindrical housing, and a plug cover. On a tip side of the insulator, an auxiliary combustion chamber is formed which is surrounded by at least the plug cover. The plug cover is provided with nozzle holes that communicate between the auxiliary combustion chamber and the outside of the auxiliary combustion chamber. A central axis of the nozzle hole is inclined with respect to a plug radial direction when viewed in a plug axial direction. At least a part around an outer opening of the nozzle hole is provided with a concave portion that is adjacent to the outer opening. The concave portion is recessed from the outside to the inside of the plug cover.

One example provides a spark plug having an insulative core extending along an axial centerline between a terminal and a firing end and including a central bore extending there through, and an insulative nose at the terminal end having an end surface. A center electrode includes an electrode head having an outer edge extending about a perimeter of the electrode head beyond a perimeter of the end surface of the insulative nose and forming a spark gap with a side electrode. The electrode includes an electrode plate, at least a portion of which is positioned axially beyond the end surface of the insulative nose and has cross-sectional which is at least greater than a cross-sectional area of the central bore. An electrode wire extends from the electrode plate into the central bore, wherein the electrode plate and electrode wire are a contiguous piece of material.

An igniter having at least two electrodes spaced from each other by an insulating member having a substantially continuous surface along a path between the electrodes. The electrodes extend substantially parallel to each other for a distance both above and below said surface. The insulating member has a channel (recess) for receiving at least a portion of a length of at least one of said electrodes below and to said surface of the insulating member. The surface of the insulating member may preferably be augmented with a conductivity enhancing agent. The insulating member and electrodes are configured so that an electric field between the electrodes at said surface does not have abrupt field intensity changes, whereby when a potential is applied to the electrodes sufficient to cause breakdown to occur between the electrodes, discharge occurs at said surface of the insulating member to define a plasma initiation region.

An igniter having at least two electrodes spaced from each other by an insulating member having a substantially continuous surface along a path between the electrodes. The electrodes extend substantially parallel to each other for a distance both above and below said surface. The insulating member has a channel (recess) for receiving at least a portion of a length of at least one of said electrodes below and to said surface of the insulating member. The surface of the insulating member may preferably be augmented with a conductivity enhancing agent. The insulating member and electrodes are configured so that an electric field between the electrodes at said surface does not have abrupt field intensity changes, whereby when a potential is applied to the electrodes sufficient to cause breakdown to occur between the electrodes, discharge occurs at said surface of the insulating member to define a plasma initiation region.

The present disclosure provides, inter alia, apparatuses for preparing a suppressor seal of a spark plug insulator assembly, and processes for fabricating and/or assembling a spark plug insulator assembly using the same. Also provided are automated systems for fabricating and/or assembling a spark plug insulator assembly, which includes an induction heating apparatus disclosed herein and other components such as, e.g., an auxiliary unit and a control unit, to automate and accelerate the manufacturing process.

A ground electrode for a spark plug includes a ground electrode body arranged to face a center electrode of the spark plug. The ground electrode includes a discharge portion mounted on the ground electrode body to face the center electrode with a spark gap between the discharge portion and the center electrode. The discharge portion is made of a platinum-based alloy of platinum, rhodium, and nickel. A first mass percent of the rhodium contained in the platinum-based alloy of the platinum, the rhodium, and the nickel is within a first range from 2 wt % to 20 wt % inclusive. A second mass percent of the nickel contained in the platinum-based alloy of the platinum, the rhodium, and the nickel being within a second range from 2.5 wt % to 12 wt % inclusive.