A spark plug has a housing of a cylindrical shape, an insulator of a cylindrical shape fitted into the inside of the housing, a center electrode and a ground electrode. No male screw part is formed on an outer peripheral surface of the housing. A housing support surface is formed on an inner peripheral surface of the housing. An outer peripheral surface of the insulator has an insulator support surface which is supported by the housing support surface in an axial direction of the spark plug. The housing has a pressure fitting part to be presses to a cylinder head of an internal combustion engine. A part of the pressure fitting part and a part of at least one of the housing support surface and the insulator support surface are arranged to be overlapped with each other in a radial direction of the spark plug.

A spark plug is provided that ensures that a ground electrode is positioned in a predefined, precise orientation when installed in a spark plug hole of an engine head. The spark plug is configured for axial insertion into the plug hole, and has a non-axisymmetric ground shield that fits into the plug hole, wherein the ground shield has an outer shield surface with a non-axisymmetric shape and the plug hole is also provided with a complementary non-axisymmetric shape. The spark plug includes a central insulator, which has an inner end surrounding a central electrode and supporting the ground shield, which is mounted on the insulator to support a ground strap adjacent the electrode for forming a spark therebetween. The insulator and ground shield are axially slidable into the plug hole, and the spark plug includes a jamb nut which is rotatable to fix the spark plug in position in a predefined orientation. Preferably, an outer surface of the insulator and an inner surface of the ground shield have complementary shapes wherein the ground shield fits closely on the insulator. For example, the outer insulator surface and the inner shield surface may have a complementary axisymmetric shape, such as cylindrical, or a non-axisymmetric shape, which may conform to the non-axisymmetric shape of the outer shield surface.

A spark plug is provided that ensures that a ground electrode is positioned in a predefined, precise orientation when installed in a spark plug hole of an engine head. The spark plug is configured for axial insertion into the plug hole, and has a non-axisymmetric ground shield that fits into the plug hole, wherein the ground shield has an outer shield surface with a non-axisymmetric shape and the plug hole is also provided with a complementary non-axisymmetric shape. The spark plug includes a central insulator, which has an inner end surrounding a central electrode and supporting the ground shield, which is mounted on the insulator to support a ground strap adjacent the electrode for forming a spark therebetween. The insulator and ground shield are axially slidable into the plug hole, and the spark plug includes a jamb nut which is rotatable to fix the spark plug in position in a predefined orientation. Preferably, an outer surface of the insulator and an inner surface of the ground shield have complementary shapes wherein the ground shield fits closely on the insulator. For example, the outer insulator surface and the inner shield surface may have a complementary axisymmetric shape, such as cylindrical, or a non-axisymmetric shape, which may conform to the non-axisymmetric shape of the outer shield surface.

Methods and systems are provided for a spark plug of an internal combustion engine. In one example, a spark plug includes a housing section having a first groove and an opposing, second groove. A tool including a first protrusion and second protrusion may couple with the first and second grooves of the spark plug in order to drive the spark plug to either of only two coupled positions with a cylinder head.

Methods and systems are provided for a spark plug of an internal combustion engine. In one example, a spark plug includes a housing section having a first groove and an opposing, second groove. A tool including a first protrusion and second protrusion may couple with the first and second grooves of the spark plug in order to drive the spark plug to either of only two coupled positions with a cylinder head.

A method of manufacturing a spark plug (1) including a disposing step, a contacting step, and a deforming step. In the disposing step, a mounting screw portion (30) is inserted into a gasket (50) and the gasket (50) is disposed between the mounting screw portion (30) and a seat portion (32). In the contacting step, from a front end side, a jig (60) is brought into contact with the gasket (50) disposed by the disposing step, and the jig (60) is moved toward the rear end side until a load applied to the jig (60) from the gasket (50) reaches a predetermined set load. In the deforming step, after the contacting step, the jig (60) is further moved toward the rear end side by a predetermined set distance XS. Consequently, the gasket (50) is pressed by the jig (60) and an inner edge portion (55) of the gasket (50) is deformed inward in a radial direction of the gasket (50).

A spark plug includes a body of revolution defining a longitudinal axis. The body has a forward axial portion with external threads, and an intermediate axial collar portion defining an axially downwardly facing sealing surface. A first electrode and a second electrode extend from the forward axial portion and define a spark gap therebetween. A hex drive portion is disposed axially above the intermediate collar portion. A gasket crush limiter includes a wall that extends axially downwardly from the intermediate axial collar portion, defining an annular pocket formed by the wall and the forward axial portion.

A spark plug includes a body of revolution defining a longitudinal axis. The body has a forward axial portion with external threads, and an intermediate axial collar portion defining an axially downwardly facing sealing surface. A first electrode and a second electrode extend from the forward axial portion and define a spark gap therebetween. A hex drive portion is disposed axially above the intermediate collar portion. A gasket crush limiter includes a wall that extends axially downwardly from the intermediate axial collar portion, defining an annular pocket formed by the wall and the forward axial portion.

An engine ignition coil assembly disclosed herein provides an ignition coil housing that may be mounted on an engine block assembly and that is isolated from engine vibrations. The engine ignition coil assembly comprises an ignition coil housing. The ignition coil housing contains an ignition coil apparatus. An electrical connector for the ignition coil apparatus is mounted to the ignition coil housing. An elastomeric boot supports the ignition coil housing and may be disposed on an engine block assembly such that ignition coil housing is spaced apart from the engine block assembly by the elastomeric boot. A single fastener extends through a fastener opening in the ignition coil housing parallel with the elastomeric boot. An elastomeric isolator is disposed on the ignition coil housing at the fastener opening around the single fastener. A proximal end of the single fastener may be fixed to the engine block assembly.

A spark plug has a specific direction orthogonal to an axial direction of a spark plug; the specific direction has opposing front directional side and rear directional side; the housing has a tip surface having a front end in the front side of the specific direction and a rear end in the rear side, the tip surface has a tip inclined surface inclined toward the tip end of the spark plug from the front end to the rear end of the tip surface. The tip inclined surface has a rear end in the specific direction, the insulator having a front end of the specific direction, the rear end is located to be closer to the tip end of the spark plug than the front end of the tip surface is, and to be more rearward than the front end of the insulator in the rear side of the specific direction.