An ignition coil is described with a housing having a tubular housing part for connecting to a spark plug, and a pin-shaped interference suppression resistor arranged in the tubular housing part. According to this disclosure, it is provided that the housing surrounds an interior which has a funnel-shaped section which tapers toward the tubular housing part. In addition, a method is described for producing such an ignition coil.

A spark plug for an internal combustion engine includes a housing, an insulator, a center electrode, a ground electrode, and a plug cover. The housing has a cylindrical shape. The insulator is held on an inner side of the housing. The insulator has a cylindrical shape. The center electrode is held on an inner side of the insulator. The ground electrode forms a discharge gap with the center electrode. The plug cover, together with the housing, configures an auxiliary combustion chamber in which the discharge gap is arranged. The plug cover includes a spray hole that communicates between the inside and outside of the plug cover. The ground electrode is connected to a plurality of locations on an auxiliary-chamber inner wall surface that includes surfaces of the housing and the plug cover that are exposed to the auxiliary combustion chamber.

A spark plug for an internal combustion engine includes a housing, an insulator, a center electrode, a ground electrode, and a plug cover. The housing has a cylindrical shape. The insulator is held on an inner side of the housing. The insulator has a cylindrical shape. The center electrode is held on an inner side of the insulator. The ground electrode forms a discharge gap with the center electrode. The plug cover, together with the housing, configures an auxiliary combustion chamber in which the discharge gap is arranged. The plug cover includes a spray hole that communicates between the inside and outside of the plug cover. The ground electrode is connected to a plurality of locations on an auxiliary-chamber inner wall surface that includes surfaces of the housing and the plug cover that are exposed to the auxiliary combustion chamber.

A spark plug includes a center electrode; a metal shell that retains the center electrode at an outer periphery of the center electrode in an insulating manner; a ground electrode disposed such that a spark gap is formed between the center electrode and an end portion of the ground electrode; and a plug cap connected to the metal shell, the plug cap covering the center electrode and the end portion of the ground electrode from front and having a through hole in a region in front of the ground electrode. An inner surface of the plug cap has at least one ridge in a first region that is in front of an inner open end of the through hole.

A spark plug includes a center electrode; a metal shell that retains the center electrode at an outer periphery of the center electrode in an insulating manner; a ground electrode disposed such that a spark gap is formed between the center electrode and an end portion of the ground electrode; and a plug cap connected to the metal shell, the plug cap covering the center electrode and the end portion of the ground electrode from front and having a through hole in a region in front of the ground electrode. An inner surface of the plug cap has at least one ridge in a first region that is in front of an inner open end of the through hole.

A spark plug capable of facilitating the growth of a flame kernel. The spark plug including a metal shell; a center electrode retained in the metal shell in an insulated manner; a ground electrode disposed such that a spark gap is formed between the center electrode and an end portion of the ground electrode; and a plug cap that covers the center electrode and the end portion of the ground electrode from the front in a region in front of the metal shell and in which a through hole is formed. An inner surface of the plug cap in a region in front of a back end of the end portion of the ground electrode and an inner surface of the through hole each have an arithmetical mean roughness of less than or equal to 6.3 m.

A spark plug capable of facilitating the growth of a flame kernel. The spark plug including a metal shell; a center electrode retained in the metal shell in an insulated manner; a ground electrode disposed such that a spark gap is formed between the center electrode and an end portion of the ground electrode; and a plug cap that covers the center electrode and the end portion of the ground electrode from the front in a region in front of the metal shell and in which a through hole is formed. An inner surface of the plug cap in a region in front of a back end of the end portion of the ground electrode and an inner surface of the through hole each have an arithmetical mean roughness of less than or equal to 6.3 m.

An internal combustion engine having: a housing with at least one cylinder and a pre-chamber spark plug; the cylinder has a piston that is able to move in the housing and delimits a combustion chamber contained in the housing; the combustion chamber has a compressed volume when the piston is at top dead center; the pre-chamber spark plug has a body, an external thread at its front end, a passage, an insulator positioned in the passage, a center electrode protruding from the front end of the insulator, and a pre-chamber-forming cap that is placed at the front end of the body and delimits a pre-chamber. The cap shields the center electrode from the combustion chamber and has at least one opening, which enables a gas exchange between the pre-chamber and the combustion chamber. In one embodiment, the total volume of the pre-chamber makes up at least 0.65% of the compressed volume of the combustion chamber.

An internal combustion engine having: a housing with at least one cylinder and a pre-chamber spark plug; the cylinder has a piston that is able to move in the housing and delimits a combustion chamber contained in the housing; the combustion chamber has a compressed volume when the piston is at top dead center; the pre-chamber spark plug has a body, an external thread at its front end, a passage, an insulator positioned in the passage, a center electrode protruding from the front end of the insulator, and a pre-chamber-forming cap that is placed at the front end of the body and delimits a pre-chamber. The cap shields the center electrode from the combustion chamber and has at least one opening, which enables a gas exchange between the pre-chamber and the combustion chamber. In one embodiment, the total volume of the pre-chamber makes up at least 0.65% of the compressed volume of the combustion chamber.

A corona ignition assembly including a firing end assembly and an ignition coil assembly connected by a high voltage connection is provided. The high voltage connection includes a high voltage insulator formed of silicon rubber. A shield formed of metal surrounds the high voltage insulator. The high voltage connection also includes an upper insert formed of metal connecting the shield to the ignition coil assembly and a lower insert formed of metal connecting the shield to the firing end assembly. First portions of the outer surface of the high voltage insulator adhere to the shield, the upper insert, and the lower insert, while second portions of the outer surface do not adhere to at least one of the shield, the upper insert, and the lower insert. A metal braid can be embedded in the high voltage insulator.