A spark plug includes a plug cover provided at a tip end portion of a housing to cover an auxiliary combustion chamber where an electrical discharge gap is located. The plug cover has a curved surface portion. The curved surface portion includes an outer curved surface convexly curved outward. The curved surface portion has an inclined injection hole formed therein to allow communication between the auxiliary combustion chamber and an outside. The inclined injection hole is opened to be inclined, relative to a plug axial direction, outward in a plug radial direction toward a tip end side. In a cross section including a central axis of the inclined injection hole and along the plug axial direction, a tangent line of a portion of the outer curved surface that overlaps an extended line of the central axis of the inclined injection hole is orthogonal to the extended line.

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 plasma assisted spark ignition system includes an ignitor and a power supply. The first ignitor includes: a casing having a first end, a second end that forms a first electrode, and a longitudinally extending passage, a second electrode which protrudes longitudinally outward from an opening at the second end of the casing and laterally spaced inwardly to form a spark gap, and an electrical insulator (dielectric) surrounding a portion of the second electrode, and which has a terminus that is at least closely spaced to an interior surface of the end of the casing. The power supply supplies a plurality of voltage pulses to the ignitor per ignition event to generate a flash over on the dielectric. Subsequent pulses in an ignition event may be at lower amplitude than an initial pulse in the ignition event. Pulses may, for example, have a duration on the order of a nanosecond.

A spark plug that prevents a decrease in strength of a member to which a mark is attached while ensuring a readability of the mark, and a method of manufacturing the spark plug. The spark plug is configured to ignite an air-fuel mixture in an internal combustion engine. The spark plug includes: a mark formed of an oxide film generated on a surface of a metallic member or is formed of the metallic member and the oxide film; and a coating material covering the whole mark and allowing transmission of light.

A spark plug that prevents a decrease in strength of a member to which a mark is attached while ensuring a readability of the mark, and a method of manufacturing the spark plug. The spark plug is configured to ignite an air-fuel mixture in an internal combustion engine. The spark plug includes: a mark formed of an oxide film generated on a surface of a metallic member or is formed of the metallic member and the oxide film; and a coating material covering the whole mark and allowing transmission of light.

The spark plug includes: an insulator having an axial hole extending in an axial direction; a center electrode disposed at a front end in the axial direction of the axial hole and having a front end portion that protrudes from a front side of the axial hole; a tubular metal shell holding the insulator; and a ground electrode having one end portion that is fixed to a through hole provided in the metal shell, the ground electrode having another end portion that forms a discharge gap between the other end portion and the front end portion of the center electrode. The through hole extends toward the front side in the axial direction, in a direction from an outer peripheral surface toward an inner peripheral surface of the metal shell. The one end portion is located on a rear side relative to the other end portion in the axial direction.

The spark plug includes: an insulator having an axial hole extending in an axial direction; a center electrode disposed at a front end in the axial direction of the axial hole and having a front end portion that protrudes from a front side of the axial hole; a tubular metal shell holding the insulator; and a ground electrode having one end portion that is fixed to a through hole provided in the metal shell, the ground electrode having another end portion that forms a discharge gap between the other end portion and the front end portion of the center electrode. The through hole extends toward the front side in the axial direction, in a direction from an outer peripheral surface toward an inner peripheral surface of the metal shell. The one end portion is located on a rear side relative to the other end portion in the axial direction.

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.

This disclosure presents, in one or more embodiments, an ignition device for a gasoline compression ignition engine. The ignition device includes a shuttle plunger with a gas chamber. The gas chamber is delimited by at least one sidewall of the shuttle plunger and captures exhaust gases. The ignition device also includes an electromagnetic coil that actuates the shuttle plunger in a first direction, a main body with a cavity containing the shuttle plunger and the electromagnetic coil, and a center electrode, fixed to the shuttle plunger, that ignites a fuel mixture.

Spark plug for igniting a combustible fuel in an internal combustion engine, wherein the spark plug has an igniter arranged at an end of the spark plug facing the combustion chamber, when the spark plug is mounted in the internal combustion engine. The spark plug includes a wall and a sealing area. The wall at least partially surrounds the igniter. The sealing area is used for sealing the combustion chamber against the environment. The wall has the sealing area located at an end of the wall, which end faces the combustion chamber when the spark plug is mounted in the internal combustion engine.