A spark plug includes a central electrode member and an outer electrode member. The central electrode member includes a central base and a plurality of electrode prongs extending in an axial direction from the central base. The outer electrode member surrounds the central electrode member. The outer electrode member includes a wall that is radially spaced from the plurality of electrode prongs to allow a series of electric arcs to form between the wall and the plurality of electrode prongs. The outer electrode member and the central electrode member are sized and positioned relative to one another such that a first rate of wear of the outer electrode member, along a longitudinal axis of the spark plug, is substantially equal to a second rate of wear of the central electrode member along the longitudinal axis.

A spark plug includes a central electrode member and an outer electrode member. The central electrode member includes a central base and a plurality of electrode prongs extending in an axial direction from the central base. The outer electrode member surrounds the central electrode member. The outer electrode member includes a wall that is radially spaced from the plurality of electrode prongs to allow a series of electric arcs to form between the wall and the plurality of electrode prongs. The outer electrode member and the central electrode member are sized and positioned relative to one another such that a first rate of wear of the outer electrode member, along a longitudinal axis of the spark plug, is substantially equal to a second rate of wear of the central electrode member along the longitudinal axis.

A method of assisting ignition of a dedicated exhaust gas recirculation (D-EGR) cylinder in a spark-ignited internal combustion engine. The spark igniter has an internal air passage that receives pressurized air and carries the pressurized air down to an exit port in the vicinity of the spark gap of the igniter.

A spark plug includes a central electrode member and an outer electrode member. The central electrode member includes a central base and a plurality of electrode prongs extending in an axial direction from the central base. The outer electrode member surrounds the central electrode member. The outer electrode member includes a wall that is radially spaced from the plurality of electrode prongs to allow a series of electric arcs to form between the wall and the plurality of electrode prongs. The outer electrode member and the central electrode member are sized and positioned relative to one another such that a first rate of wear of the outer electrode member, along a longitudinal axis of the spark plug, is substantially equal to a second rate of wear of the central electrode member along the longitudinal axis.

A spark plug includes a central electrode member and an outer electrode member. The central electrode member includes a central base and a plurality of electrode prongs extending in an axial direction from the central base. The outer electrode member surrounds the central electrode member. The outer electrode member includes a wall that is radially spaced from the plurality of electrode prongs to allow a series of electric arcs to form between the wall and the plurality of electrode prongs. The outer electrode member and the central electrode member are sized and positioned relative to one another such that a first rate of wear of the outer electrode member, along a longitudinal axis of the spark plug, is substantially equal to a second rate of wear of the central electrode member along the longitudinal axis.

The ignition control device includes a spark plug that includes a first electrode and a second electrode disposed so as to oppose each other, an ignition coil that includes a plurality of sets of a primary coil and a secondary coil, generates a high voltage in the secondary coil by energizing or interrupting a primary current supplied to the primary coil, and applies the generated high voltage to the first electrode, and a control unit that, in a case where a plurality of the primary coils are driven during a single ignition process, temporarily stops energization of a primary current supplied to a second primary coil when a primary current supplied to a first primary coil is interrupted, and re-energizes the primary current supplied to the second primary coil following the elapse of an energization stoppage period.

A spark plug includes a cylindrical metallic shell having a ground electrode at a forward end of the cylindrical metallic shell, a cylindrical insulator held in the metallic shell, a center electrode disposed in the insulator, a resistor element disposed in the insulator and having a forward end located rearward of a rear end of the center electrode, a forward-end-side electrically conductive seal layer disposed in the insulator to be located between the center electrode and the resistor element, and a rear-end-side electrically conductive seal layer disposed in the insulator to be located rearward of the resistor element. The forward end of the resistor element is located forward of the rear end of the metallic shell, and the rear end of the resistor element is located rearward of the rear end of the metallic shell.

A spark plug includes a cylindrical metallic shell having a ground electrode at a forward end of the cylindrical metallic shell, a cylindrical insulator held in the metallic shell, a center electrode disposed in the insulator, a resistor element disposed in the insulator and having a forward end located rearward of a rear end of the center electrode, a forward-end-side electrically conductive seal layer disposed in the insulator to be located between the center electrode and the resistor element, and a rear-end-side electrically conductive seal layer disposed in the insulator to be located rearward of the resistor element. The forward end of the resistor element is located forward of the rear end of the metallic shell, and the rear end of the resistor element is located rearward of the rear end of the metallic shell.

A small-size injector having a built-in ignition device which can surely inject fuel and ignite the fuel with low electric power by the ignition device with a simple configuration is provided. The injector comprises a fuel injecting device 2 having a fuel injecting port 20 that injects the fuel, an ignition device 3 configured to ignite the injected fuel, and a casing 10 inside housing therein the fuel injecting device 2 and the ignition device 3 together. The motion device 3 is constituted of a plasma generator 3 which integrally comprises a booster 5 having a resonation structure capacity-coupled with an electromagnetic wave oscillator MW configured to oscillate an electromagnetic wave, and a discharger 6 configured to cause a discharge of a high voltage generated by the booster 5.

A small-size injector having a built-in ignition device which can surely inject fuel and ignite the fuel with low electric power by the ignition device with a simple configuration is provided. The injector comprises a fuel injecting device 2 provided with a fuel injecting port 20 configured to inject the fuel, an ignition device 3 configured to ignite the injected fuel, and a casing 10 inside housing therein the fuel injecting device 2 and the ignition device 3 together. The ignition device 3 is constituted of a plasma generator 3 which integrally comprises a booster 5 having a resonation structure capacity-coupled with an electromagnetic wave oscillator MW configured to oscillate an electromagnetic wave, and a discharger 6 configured to cause a discharge of a high voltage generated by the booster 5.