A car ignition device and an ignition accelerator are disclosed. The car ignition device includes a magnetic shielding conductive element, a spark plug and a magnetic element. The magnetic shielding conductive element has a first disposing portion and a second disposing portion. One end of the spark plug is disposed inside the first disposing portion and electrically connected with the magnetic shielding conductive element. The magnetic element is disposed at the second disposing portion, and has a north-seeking pole and a south-seeking pole. The north-seeking pole is located at one side of the magnetic element near the spark plug. The south-seeking pole is located at another side of the magnetic element away from the spark plug. The magnetic shielding conductive element shields a magnetic force of the magnetic element in a direction toward the spark plug. The invention has higher ignition efficiency.

A car ignition device and an ignition accelerator are disclosed. The car ignition device includes a magnetic shielding conductive element, a spark plug and a magnetic element. The magnetic shielding conductive element has a first disposing portion and a second disposing portion. One end of the spark plug is disposed inside the first disposing portion and electrically connected with the magnetic shielding conductive element. The magnetic element is disposed at the second disposing portion, and has a north-seeking pole and a south-seeking pole. The north-seeking pole is located at one side of the magnetic element near the spark plug. The south-seeking pole is located at another side of the magnetic element away from the spark plug. The magnetic shielding conductive element shields a magnetic force of the magnetic element in a direction toward the spark plug. The invention has higher ignition efficiency.

A spark plug includes an insulator body and a central electrode having a spark-end and a terminal-end. The central electrode is disposed within the insulator body, with the spark-end and the terminal-end protruding from the insulator body at opposite ends thereof. A metal electrode surrounds the insulator body and extends to form a gap with the central electrode at the spark-end. A capacitor with metalized inner and outer surfaces is provided, with the metalized inner surface being connected to the central electrode and the metalized outer surface being connected to the metal electrode. A first resistive component is embedded within the central electrode between the capacitor and the terminal-end, and a second resistive component embedded within the central electrode between the capacitor and the spark-end.

A spark plug includes an insulator body and a central electrode having a spark-end and a terminal-end. The central electrode is disposed within the insulator body, with the spark-end and the terminal-end protruding from the insulator body at opposite ends thereof. A metal electrode surrounds the insulator body and extends to form a gap with the central electrode at the spark-end. A capacitor with metalized inner and outer surfaces is provided, with the metalized inner surface being connected to the central electrode and the metalized outer surface being connected to the metal electrode. A first resistive component is embedded within the central electrode between the capacitor and the terminal-end, and a second resistive component embedded within the central electrode between the capacitor and the spark-end.

A spark plug having a connection portion disposed between a metal terminal and a center electrode. The connection portion includes: a magnetic substance formed from a Fe-containing oxide; a conductor which is a wire helically disposed on an outer periphery of the magnetic substance and electrically connected to the metal terminal and the center electrode; and an intermediate member which is in contact with the magnetic substance, the conductor, and an inner peripheral surface of the insulator, is disposed between the magnetic substance and the conductor, and the inner peripheral surface of the insulator, and has lower electrical conductivity than the conductor. The conductor is made of one or more of an oxide conductor, carbon, and a carbon compound.

A spark plug having a connection portion disposed in the axial hole and between a metal terminal and a center electrode. The connection portion includes: a magnetic substance formed from a Fe-containing oxide; a conductor helically disposed on an outer periphery of the magnetic substance and electrically connected to the metal terminal and the center electrode; and an intermediate member disposed between the magnetic substance and the conductor, and an inner peripheral surface of the insulator and having lower electrical conductivity than the conductor. The conductor includes a base and a conductive layer disposed on an outer periphery of the base and having higher electrical conductivity than the base, and the conductive layer has a thickness of larger than 0.1 m and equal to or smaller than 25 m.

A spark plug having a connection portion disposed in the axial hole and between a metal terminal and a center electrode. The connection portion includes: a magnetic substance formed from a Fe-containing oxide; a conductor helically disposed on an outer periphery of the magnetic substance and electrically connected to the metal terminal and the center electrode; and an intermediate member disposed between the magnetic substance and the conductor, and an inner peripheral surface of the insulator and having lower electrical conductivity than the conductor. The conductor includes a base and a conductive layer disposed on an outer periphery of the base and having higher electrical conductivity than the base, and the conductive layer has a thickness of larger than 0.1 m and equal to or smaller than 25 m.

A spark plug having a resistor disposed between a metal terminal and a center electrode so as to be electrically connected to the metal terminal and the center electrode, wherein the resistor is in contact with an inner circumferential surface of the insulator. On a cross section taken along the axial line so as to include the axial line, in a case where a plurality of points are plotted at predetermined intervals in a direction of the axial line so as to be present on a partial boundary line, within an arbitrary range in the direction of the axial line, of a boundary line between the insulator and the resistor, and a regression line is drawn by a least-squares method with use of the plurality of points, an average value of distances in a direction perpendicular to the regression line between the regression line and the partial boundary line is 0.1 to 0.3 m.

A spark plug having a resistor disposed between a metal terminal and a center electrode so as to be electrically connected to the metal terminal and the center electrode, wherein the resistor is in contact with an inner circumferential surface of the insulator. On a cross section taken along the axial line so as to include the axial line, in a case where a plurality of points are plotted at predetermined intervals in a direction of the axial line so as to be present on a partial boundary line, within an arbitrary range in the direction of the axial line, of a boundary line between the insulator and the resistor, and a regression line is drawn by a least-squares method with use of the plurality of points, an average value of distances in a direction perpendicular to the regression line between the regression line and the partial boundary line is 0.1 to 0.3 m.

Disclosed is a spark plug capable of preventing electrode wear while ensuring impact resistance. In the spark plug, a conductive seal is arranged between a rear end portion of a center electrode and a resistor within an axial hole of an insulator. The conductive seal includes a side-surface seal layer brought into contact with the whole of a side surface of the rear end portion of the center electrode and having a thickness of 10 m or larger in an axis perpendicular direction. Assuming that a projection area is defined by projecting the center electrode onto the axial hole in the axis perpendicular direction around a center axis of the spark plug, a contact surface of the resistor brought into contact with the axial hole overlaps at last a part of the projection area.