A spark plug combustion ionization sensor for measuring ion current inside the cylinder of an internal combustion engine. The sensor measures ion current which flows when the energy released during combustion ionizes the air inside the cylinder, and thus can detect combustion and emission parameters. The spark plug combustion ionization sensor generally includes an insulated, dedicated sensing electrode, separate from the sparking electrode of a spark plug. The sensing electrode may also be shielded to further reduce interference such as electromagnetic interference (EMI). The use of a dedicated electrode allows for ion current measurement with less electromagnetic noise from the ignition process, and also eliminates the need for circuitry that is typically necessary when the sparking electrode is also used to sense ion current.

An ignition system includes an ignition coil with a primary winding and a secondary winding having a terminal for providing a high voltage (HV). An electrode arrangement of an igniter includes first and second HV electrodes coupled to the terminal of the secondary winding. The igniter also has at least one ground electrode. A first spark gap is defined between the first HV electrode and the at least one ground electrode, and a second spark gap is defined between the second HV electrode and the at least one ground electrode. A first capacitor is disposed in-line between the first HV electrode and the terminal of the secondary winding and a second capacitor disposed in-line between the second HV electrode and the terminal of the secondary winding of the ignition coil. The ignition system includes a driver module coupled to a terminal of the primary winding, for driving the ignition coil.

A multipoint spark plug includes side electrodes provided in a pair so as to extend in a lengthwise direction of a tip end portion via a gap, and an intermediate electrode provided in the gap between the pair of side electrodes such that a plurality of ignition gaps are formed in the lengthwise direction of the tip end portion. An electrode holding portion is formed from separate parts that hold the side electrodes and the intermediate electrode, respectively, so as to insulate the side electrodes and the intermediate electrode from the main body portion, and the respective parts thereof project into the combustion chamber from the tip end portion.

A multipoint spark plug includes side electrodes provided in a pair so as to extend in a lengthwise direction of a tip end portion via a gap, and an intermediate electrode provided in the gap between the pair of side electrodes such that a plurality of ignition gaps are formed in the lengthwise direction of the tip end portion. An electrode holding portion is formed from separate parts that hold the side electrodes and the intermediate electrode, respectively, so as to insulate the side electrodes and the intermediate electrode from the main body portion, and the respective parts thereof project into the combustion chamber from the tip end portion.

[PROBLEMS] An ignition plug is provided, in which a tip end part of a central electrode is not eroded and an electric power loss of the electromagnetic wave can be reduced, even in a case where a configuration is performed such that a high voltage for discharge and an electromagnetic wave are supplied from a terminal part side of an ignition plug. An electrode part 2 comprises a central electrode 2A including an electrode chip part for generating the spark discharge with the ground electrode 5, and a cylindrical insulating tube member 2B for covering the central electrode 2A. On the outer peripheral surface of the insulating tube member 2B, a conductive member 21 is provided so as to electrically connect the central electrode 2A with a terminal part 20 for receiving an electric power from the outside.

The igniter can have a first conductor having a tip extending along an axis and forming a positive terminal; a second conductor having a tip surrounding the tip of the first conductor around the axis and forming a negative terminal; an insulator filling a space between the first conductor and the second conductor, a spark path extending radially, relative the axis, between the tip of the first conductor and the tip of the second conductor, from the positive terminal to the negative terminal; at least one magnet operable to generate a magnetic field B, the magnetic field B having a magnetic field orientation extending circumferentially around the axis, the at least one magnet disposed radially, relative the axis, between the first conductor and the second conductor, the at least one magnet embedded within the insulator.

The igniter can have a first conductor having a tip extending along an axis and forming a positive terminal; a second conductor having a tip surrounding the tip of the first conductor around the axis and forming a negative terminal; an insulator filling a space between the first conductor and the second conductor, a spark path extending radially, relative the axis, between the tip of the first conductor and the tip of the second conductor, from the positive terminal to the negative terminal; at least one magnet operable to generate a magnetic field B, the magnetic field B having a magnetic field orientation extending circumferentially around the axis, the at least one magnet disposed radially, relative the axis, between the first conductor and the second conductor, the at least one magnet embedded within the insulator.

A spark plug, including a central electrode, a first ground electrode, which is situated in a curved shape having a horizontal area and an essentially vertical area, and at least one second ground electrode, which is situated adjacent to the central electrode in such a way that a distance between the first ground electrode and the central electrode is less than a distance between the second ground electrode and the central electrode.

A spark plug, including a central electrode, a first ground electrode, which is situated in a curved shape having a horizontal area and an essentially vertical area, and at least one second ground electrode, which is situated adjacent to the central electrode in such a way that a distance between the first ground electrode and the central electrode is less than a distance between the second ground electrode and the central electrode.

An igniter having at least two electrodes spaced from each other by an insulating member having a substantially continuous surface along a path between the electrodes. The electrodes extend substantially parallel to each other for a distance both above and below said surface. The insulating member has a channel (recess) for receiving at least a portion of a length of at least one of said electrodes below and to said surface of the insulating member. The surface of the insulating member may preferably be augmented with a conductivity enhancing agent. The insulating member and electrodes are configured so that an electric field between the electrodes at said surface does not have abrupt field intensity changes, whereby when a potential is applied to the electrodes sufficient to cause breakdown to occur between the electrodes, discharge occurs at said surface of the insulating member to define a plasma initiation region.