Abstract: A pre-chamber spark plug. The pre-chamber spark plug includes a central electrode and at least one ground electrode, a housing, an insulator that electrically insulates the central electrode from the housing, a cap having at least one cap hole, and a pre-chamber having a defined gas volume. The insulator includes a base portion which protrudes into the pre-chamber in the axial direction over a base length and which is in contact with the gas volume, and wherein a ratio of the gas volume to the base length is in a range of: R=40 to 300 mm2.

Abstract: A prechamber spark plug. The prechamber spark plug includes a housing having an external thread with a start of thread, a central electrode and a ground electrode, the central electrode and the ground electrode being arranged in a prechamber, and a cap that closes the prechamber in the direction of a combustion chamber, through-holes for a connection between the prechamber and an outer side of the prechamber spark plug being configured in the housing.

Abstract: A pre-chamber spark plug includes (i) a middle electrode with a first noble metal body which has a first end spark face, (ii) a ground electrode with a second noble metal body which has a second end spark face, (iii) a housing, with the ground electrode being fixed in the housing, (iv) an insulator which electrically insulates the middle electrode with respect to the ground electrode, and (v) a cap, which together with a part of the housing, defines a pre-chamber. The first end spark face and the second end spark face are arranged oppositely at a distance from one another.

Abstract: An internal combustion engine. The internal combustion engine includes: at least one cylinder in which a combustion chamber is formed, the combustion chamber being delimited by side walls of the cylinder and a combustion chamber roof, which is formed by a cylinder head of the cylinder, and a piston that can move in the cylinder; and a spark plug with a longitudinal axis including: a housing with a combustion chamber-facing end face, an insulator disposed in the housing, a center electrode disposed in the insulator, and at least one ground electrode disposed on or in the housing and, together with the center electrode, forms at least one spark gap. The spark plug is mounted in a bore formed in the cylinder head and is designed to ignite a fuel/air mixture in the combustion chamber. The spark gap of the spark plug is located outside the combustion chamber.

Abstract: A spark plug having a longitudinal axis. The spark plug includes: a housing having a bore along the spark plug longitudinal axis and a combustion-chamber-side end face; an insulator arranged at least partially within the housing, and having an insulator base extending from a combustion-chamber-side end face of the insulator to an insulator base neck; a central electrode arranged at least partially within the insulator; and a ground electrode arranged on the housing, the ground electrode and the central electrode being arranged so that the at least one ground electrode forms a spark gap with the central electrode, a width of the spark gap being defined by an inter-electrode distance between the central electrode and the ground electrode. The inter-electrode distance between the central electrode and the ground electrode is not greater than 0.4 mm. The spark gap is formed at least partially within the housing.

Abstract: A pre-chamber spark plug. The pre-chamber spark plug includes a housing, a pre-chamber, a cap that closes the pre-chamber on the housing and that has one or more through-openings, and an ignition device situated in the pre-chamber. The cap has a cap base and a cap jacket. The cap jacket and a housing inner wall of the housing defines a pre-chamber inner wall. The pre-chamber is defined by the pre-chamber inner wall and the cap base. At least one rib projects into the pre-chamber is formed in the region of the pre-chamber inner wall.

Abstract: A prechamber spark plug. The prechamber spark plug includes a housing having an external thread with a start of thread, a central electrode and a ground electrode, the central electrode and the ground electrode being arranged in a prechamber, and a cap that closes the prechamber in the direction of a combustion chamber, through-holes for a connection between the prechamber and an outer side of the prechamber spark plug being configured in the housing.

Abstract: A prechamber spark plug. The spark plug includes a housing, a cap, which defines a prechamber at least partially, and which includes a plurality of through holes that are configured to produce a connection between the prechamber and a combustion chamber of an internal combustion engine; the through holes each having a hole center line; the cap including a recess at a region pointed towards the housing, the recess abutting the housing at a combustion-chamber-side end of the housing; a distance from an exit point of a through hole lying on the hole center line, to a recess, being in a range of 2 mm to 7 mm; and a first angle between a center axis of the prechamber spark plug and the hole center line being in a range of 30° to 70°. An internal combustion engine including such a prechamber spark plug is also described.

Abstract: A pre-chamber spark plug. The pre-chamber spark plug includes a housing, a pre-chamber, a cap that closes the pre-chamber on the housing and that has one or more through-openings, and an ignition device situated in the pre-chamber. The cap has a cap base and a cap jacket. The cap jacket and a housing inner wall of the housing defines a pre-chamber inner wall. The pre-chamber is defined by the pre-chamber inner wall and the cap base. At least one rib projects into the pre-chamber is formed in the region of the pre-chamber inner wall.

Abstract: A batch of spark plugs. Each spark plug has a longitudinal axis, a central electrode oriented in the direction of the longitudinal axis, a ground electrode oriented at an angle to the longitudinal axis, such that a spark gap is formed between a tip of the central electrode and a tip of the ground electrode, and an outer thread for screwing the spark plug in the longitudinal direction into an inner thread of a cylinder head of a combustion chamber of an internal combustion engine, and has an annular contact surface oriented perpendicularly to the longitudinal axis and intended for bringing the spark plug to rest against the cylinder head. After the spark plugs have been screwed into the inner thread of the cylinder head, the ground electrodes have the same orientation with regard to a rotation about the longitudinal axis of the spark plug relative to the combustion chamber.

Abstract: A prechamber spark plug, including center and ground electrodes, a housing having an external thread, a cap arranged on the housing and together with the housing defines a prechamber, and an insulator which electrically insulates the center electrode from the housing. The external thread has a thread length in the axial direction. The housing is fastened to the insulator at first and second fixing regions so that a first clamping force at the first fixing region acts from the housing on the insulator, and a second clamping force at the second fixing region acts from the housing on the insulator. The first and second clamping forces are directed in opposite directions to one another in the axial direction. A distance between the first and second fixing regions in the axial direction defines a clamping length. A ratio between the thread length and the clamping length is between 0.7 to 1.3.

Abstract: A prechamber spark plug, including center and ground electrodes, a housing having an external thread, a cap arranged on the housing and together with the housing defines a prechamber, and an insulator which electrically insulates the center electrode from the housing. The external thread has a thread length in the axial direction. The housing is fastened to the insulator at first and second fixing regions so that a first clamping force at the first fixing region acts from the housing on the insulator, and a second clamping force at the second fixing region acts from the housing on the insulator. The first and second clamping forces are directed in opposite directions to one another in the axial direction. A distance between the first and second fixing regions in the axial direction defines a clamping length. A ratio between the thread length and the clamping length is between 0.7 to 1.3.

Abstract: A pre-chamber spark plug includes (i) a middle electrode with a first noble metal body which has a first end spark face, (ii) a ground electrode with a second noble metal body which has a second end spark face, (iii) a housing, with the ground electrode being fixed in the housing, (iv) an insulator which electrically insulates the middle electrode with respect to the ground electrode, and (v) a cap, which together with a part of the housing, defines a pre-chamber. The first end spark face and the second end spark face are arranged oppositely at a distance from one another.

Abstract: A method for manufacturing a prechamber spark plug including an external thread and a cap including at least one through-opening. The method includes: providing the prechamber spark plug without a cap and including a cylindrical circumferential surface for the external thread. Mounting the cap, which includes at least one through-opening, in an arbitrary alignment at the prechamber spark plug, and creating the external thread at the circumferential surface in such a way that a thread start and/or a thread end of the external thread is aligned in relation to the through-opening at a predetermined position.

Abstract: A prechamber spark plug. The spark plug includes a housing, a cap, which defines a prechamber at least partially, and which includes a plurality of through holes that are configured to produce a connection between the prechamber and a combustion chamber of an internal combustion engine; the through holes each having a hole center line; the cap including a recess at a region pointed towards the housing, the recess abutting the housing at a combustion-chamber-side end of the housing; a distance from an exit point of a through hole lying on the hole center line, to a recess, being in a range of 2 mm to 7 mm; and a first angle between a center axis of the prechamber spark plug and the hole center line being in a range of 30° to 70°. An internal combustion engine including such a prechamber spark plug is also described.

Abstract: A batch of spark plugs. Each spark plug has a longitudinal axis, a central electrode oriented in the direction of the longitudinal axis, a ground electrode oriented at an angle to the longitudinal axis, such that a spark gap is formed between a tip of the central electrode and a tip of the ground electrode, and an outer thread for screwing the spark plug in the longitudinal direction into an inner thread of a cylinder head of a combustion chamber of an internal combustion engine, and has an annular contact surface oriented perpendicularly to the longitudinal axis and intended for bringing the spark plug to rest against the cylinder head. After the spark plugs have been screwed into the inner thread of the cylinder head, the ground electrodes have the same orientation with regard to a rotation about the longitudinal axis of the spark plug relative to the combustion chamber.

Abstract: A method for manufacturing a prechamber spark plug including an external thread and a cap including at least one through-opening. The method includes: providing the prechamber spark plug without a cap and including a cylindrical circumferential surface for the external thread. Mounting the cap, which includes at least one through-opening, in an arbitrary alignment at the prechamber spark plug, and creating the external thread at the circumferential surface in such a way that a thread start and/or a thread end of the external thread is aligned in relation to the through-opening at a predetermined position.

Abstract: A spark plug including a housing, an insulator, a center electrode, and a ground electrode situated at a combustion chamber-side end of the housing. The insulator has an insulator collar, an insulator base, and a transition area, which rests on a projection of the housing. A breathing space is configured at the combustion chamber-side end of the spark plug and is delimited by a section of the inner side of the housing and a section of the insulator base. The section of the insulator base has a rounding including a first leg length and a second leg length angled with respect to the first leg length, the first leg length extending between the intersecting point of the leg lengths with one another and a first end point of the rounding, and the second leg length extending between the intersecting point and a second end point of the rounding.

Abstract: A spark plug including a housing, an insulator, a center electrode, and a ground electrode situated at a combustion chamber-side end of the housing. The insulator has an insulator collar, an insulator base, and a transition area, which rests on a projection of the housing. A breathing space is configured at the combustion chamber-side end of the spark plug and is delimited by a section of the inner side of the housing and a section of the insulator base. The section of the insulator base has a rounding including a first leg length and a second leg length angled with respect to the first leg length, the first leg length extending between the intersecting point of the leg lengths with one another and a first end point of the rounding, and the second leg length extending between the intersecting point and a second end point of the rounding.

Abstract: A prechamber spark plug for an internal combustion engine with the following features: a body with an external thread at its front end for screwing the spark plug into the engine; the external thread has a center line and begins with a thread start at the front end; the body has a passage in which an insulator is fastened and a center electrode protrudes from the front end of this insulator; at the front end of the body, a prechamber-forming cap is provided, which delimits a prechamber and shields the center electrode from a combustion chamber of the engine after the spark plug has been installed in the engine; the cap has at least one opening, which has a predefined orientation in relation to the thread start and is oriented obliquely to the center line of the external thread so as to permit a gas exchange between the prechamber and the space outside the prechamber.