A prechamber sparkplug includes a housing having a nozzle with a prechamber formed therein, and each of a first set and a second set of electrode prongs within the prechamber. The second set of electrode prongs downwardly depend from attachment points to the housing, and form, together with the first set of electrode prongs, spark gaps within the prechamber. Each of the anode-cathode pairs formed by the sets of electrode prongs is spaced radially inward a clearance distance from the prechamber wall to position the spark gaps in a flow of swirled gases. The flow of swirled gases displaces a flame kernel formed at the spark gaps to inhibit quenching.

A prechamber sparkplug includes a housing having a nozzle with a prechamber formed therein, and each of a first set and a second set of electrode prongs within the prechamber. The second set of electrode prongs downwardly depend from attachment points to the housing, and form, together with the first set of electrode prongs, spark gaps within the prechamber. Each of the anode-cathode pairs formed by the sets of electrode prongs is spaced radially inward a clearance distance from the prechamber wall to position the spark gaps in a flow of swirled gases. The flow of swirled gases displaces a flame kernel formed at the spark gaps to inhibit quenching.

A prechamber sparkplug assembly includes a sparkplug, and a sparkplug housing having a prechamber tip. The sparkplug housing includes a plug bore centered on a longitudinal axis of the sparkplug housing and receiving the sparkplug, an inside radial wall extending around the plug bore, and an outside radial wall. A cooling cavity is formed between the inside radial wall and the outside radial wall. Coolant ports extend through the outside radial wall and fluidly connect to the cooling cavity to place the cooling cavity in fluid communication with a water jacket in a cylinder head.

A prechamber sparkplug assembly includes a sparkplug, and a sparkplug housing having a prechamber tip. The sparkplug housing includes a plug bore centered on a longitudinal axis of the sparkplug housing and receiving the sparkplug, an inside radial wall extending around the plug bore, and an outside radial wall. A cooling cavity is formed between the inside radial wall and the outside radial wall. Coolant ports extend through the outside radial wall and fluidly connect to the cooling cavity to place the cooling cavity in fluid communication with a water jacket in a cylinder head.

A spark plug includes: a cylindrical insulator; a center electrode, held on an inner circumferential side of the insulator, protruding from the insulator toward a tip end side; a cylindrical housing holding the insulator on an inner circumferential side; a ground electrode forming a discharge gap between the ground electrode and the center electrode on the inner circumferential side of the housing; and a plug cover provided in a tip end portion of the housing to cover a pre-combustion chamber in which the discharge gap is arranged. The plug cover is provided with an injection hole that communicates the pre-combustion chamber to the outside. The ground electrode includes a discharge-side end portion that faces the discharge gap and a joining-side end portion that is joined to the housing. The discharge-side end portion is arranged further toward a base end side in an axial direction than the joining-side end portion is.

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 prechamber spark plug. The prechamber spark plug includes: a housing, and a cap which has at least one pass-through opening, the cap being situated at a combustion chamber-side end of the housing. The cap and the housing form a prechamber. An outer cap surface area of the cap, which faces away from the prechamber, has at least one predefined ratio to respectively one further geometric feature of the cap.

A prechamber spark plug. The prechamber spark plug includes: a housing, and a cap which has at least one pass-through opening, the cap being situated at a combustion chamber-side end of the housing. The cap and the housing form a prechamber. An outer cap surface area of the cap, which faces away from the prechamber, has at least one predefined ratio to respectively one further geometric feature of the cap.

A spark-plug wire includes a boot of electrically insulative material defining a central bore configured to receive a spark plug, an electrical connector disposed in the central bore and configured to connect with the spark plug, and a cylindrical heat shield circumscribing the boot. The heat shield has retaining features extending past a distal end of the boot and configured to radially flex to engage with a hex of the spark plug to increase a retaining force of the spark-plug wire to the spark plug.

A spark-plug wire includes a boot of electrically insulative material defining a central bore configured to receive a spark plug, an electrical connector disposed in the central bore and configured to connect with the spark plug, and a cylindrical heat shield circumscribing the boot. The heat shield has retaining features extending past a distal end of the boot and configured to radially flex to engage with a hex of the spark plug to increase a retaining force of the spark-plug wire to the spark plug.