A spark plug electrode with one or more electrode tip(s) formed on one or more electrode base(s) using an additive manufacturing process, such as a powder bed fusion technique, such that each electrode tip overhangs an edge of a corresponding electrode base. The spark plug electrode may be a center electrode, a ground electrode, or an annular ground electrode and can be provided according to a number of different configurations. Each electrode tip includes a precious metal-based material, such as an iridium- or platinum-based alloy, and a plurality of laser deposition layers, and each electrode tip can be secured to an electrode base with a weldless joint. An additive manufacturing process is also provided.

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 includes a main ground electrode having a main connecting portion connected to the housing and forming a discharge gap between the main ground electrode and the center electrode, and a sub ground electrode having a sub connecting portion connected to the housing. The direction on which the main connecting portion and a plug center axis are arranged is set to be perpendicular to an air flow direction of an air stream in the combustion chamber. The sub connecting portion is located in a downstream side than the main connecting portion. The tip end position of the sub ground electrode in the plug axial direction is located in farther tip end side than that of the main ground electrode is. The sub ground electrode is configured such that an end point of the discharge spark is movable on the sub ground electrode.

Disclosed is a spark plug including: an insulator having an axial hole formed along an axis of the spark plug; a center electrode disposed in a front end side of the axial hole; and a metal shell fixed around an outer circumference of the insulator, with a front end portion of the insulator protruding frontward from a front end of the metal shell. The front end portion of the insulator consists only of a first section and a second section located adjacent to and frontward of the first section and having an inner diameter larger than that of the first section. The second section has a chamfered area formed on an inner circumferential surface thereof so as to continue to a front end of the insulator.

A spark plug including a pre-chamber for an engine is provided. The spark plug extends along a spark plug longitudinal axis. The spark plug includes a first cylindrical structure having a wall defining a bore. An electrode is positioned inside the bore such that the electrode is spaced apart from the wall to define at least one electrode spark gap. The spark plug further includes a second cylindrical structure configured to receive the first cylindrical structure. The second cylindrical structure has one or more access apertures configured to facilitate access to the wall of the first cylindrical structure, wherein a plane perpendicular to the spark plug longitudinal axis passes through the electrode spark gap and intersects the one or more access apertures.

A spark plug assembly configured to allow multi-channel automotive spark-plugs to operate without radio-frequency interference in piston-engine powered aircraft and to greatly reduce or eliminate spark-plug fouling from carbon or lead deposits resulting from combustion of fuel in order to enhance starting and smooth operation of the aircraft engine, and thereby improve the quality of exhaust emissions by assuring a more complete burn of the fuel constituents.

An erosion of an electrode is prevented in a spark plug that performs an ignition by use of a spark discharge and an electromagnetic wave. The spark plug that a pulse voltage for a spark discharge and an electromagnetic wave supplied into the spark discharge as an energy are applied to a center electrode, the spark plug comprises the center electrode, an insulator including an axis hole into which the center electrode is engaged, a ground electrode configured to form a space between the ground electrode and the center electrode in which the spark discharge is generated, and a cylindrical conductor that is arranged at an outer circumference of the insulator, and an annular member is formed at an inner circumference of the cylindrical conductor and at a position where a distance from a distal end surface of the cylindrical conductor is within a range between wavelength and wavelength of the electromagnetic wave.

In an ignition plug, since a ground electrode is formed in a thin-rod-shape or a mesh-like shape, sufficiently strong radicals are locally generated by a barrier discharge, an anti-inflammation effect by the electrode is small, and the growth of a flame is hardly hindered. Furthermore, by making the thickness dimension of a second dielectric facing a discharge region uniform, the barrier discharge is spread over the surface of the second dielectric, the generation of the radicals is maintained, and combustibility after ignition is promoted. Furthermore, because an end portion of a high voltage electrode and a ground electrode are disposed to face each other within a combustion chamber, a fuel gas introduced into the combustion chamber is liable to flow into the discharge region, and is easily ignited by the radicals generated due to the discharge.

A pre-chamber spark plug for an internal combustion engine having: a body with a passage in which an insulator is fastened and a center electrode protrudes; at least one ground electrode extending in a straight line forms a spark gap with the center electrode; a pre-chamber-forming cap which delimits a pre-chamber and shields the center and ground electrodes from a combustion chamber after the spark plug has been installed in the engine, wherein the cap has at least one opening which permits a gas exchange between the pre-chamber and the space outside the pre-chamber. The ground electrode includes a reinforcing component welded to an end surface of a supporting component, and the supporting component is either welded to an end surface of the body or is welded to a step that is formed on the end surface.

A spark plug has a central electrode and a plurality of peripheral electrodes. The central electrode has a proximal portion and a distal portion. The distal portion of the central electrode has a circular cross-section with a longitudinal axis and terminates in a distal end. Each peripheral electrode has a lower portion and an upper portion. Each upper portion has a distal-most point. Each distal-most point is disposed in a central plane within which the longitudinal axis of the distal portion of the central electrode is wholly disposed. The cross-section of each upper portion taken along its central plane defines a convex outer side and a non-convex inner side. Each convex outer side has a curved surface which is tangent to a plurality of tangent planes, all of which intersect the longitudinal axis of the distal portion of the central electrode at points at or above the distal end of the distal point of the central electrode.