A fuel injector is configured so that, when seen from a top view of a combustion chamber, a first fuel spray flux and a second fuel spray flux sandwich an electrode part of a spark plug, and the electrode part is located outside of contour surfaces of the two fuel spray fluxes. A first injection angle between a center line of the first fuel spray flux and a vertical line and a second injection angle between a center line of the second fuel spray flux and the vertical line are larger than an angle between a center line of any other fuel spray flux and the vertical line. The second injection angle is made smaller than the first injection angle so that a distance from the electrode part to the contour surface of the second fuel spray flux is larger than a distance from the electrode part to the contour surface of the first fuel spray flux.

A fuel injector is configured so that, when seen from a top view of a combustion chamber, a first fuel spray flux and a second fuel spray flux sandwich an electrode part of a spark plug, and the electrode part is located outside of contour surfaces of the two fuel spray fluxes. A first injection angle between a center line of the first fuel spray flux and a vertical line and a second injection angle between a center line of the second fuel spray flux and the vertical line are larger than an angle between a center line of any other fuel spray flux and the vertical line. The second injection angle is made smaller than the first injection angle so that a distance from the electrode part to the contour surface of the second fuel spray flux is larger than a distance from the electrode part to the contour surface of the first fuel spray flux.

A passive prechamber spark plug for use in a combustion chamber of a vehicle engine includes an upper prechamber having an upper opening where the upper prechamber is connectable to the combustion chamber via the upper opening. An air ignition spark is formable via an upper air spark gap. A central electrode is disposed in an upper region of the upper prechamber where a base of the upper prechamber opposite the upper region is an insulator. An electrically conductive element or a slot is guided by the insulator continuously from the upper prechamber into a lower region under the base and the lower region is either a lower prechamber or is arrangeable directly in the combustion chamber. An earth electrode is disposed in the lower region such that a lower air-surface gap spark gap is formed between the earth electrode and the electrically conductive element or the slot.

A passive prechamber spark plug for use in a combustion chamber of a vehicle engine includes an upper prechamber having an upper opening where the upper prechamber is connectable to the combustion chamber via the upper opening. An air ignition spark is formable via an upper air spark gap. A central electrode is disposed in an upper region of the upper prechamber where a base of the upper prechamber opposite the upper region is an insulator. An electrically conductive element or a slot is guided by the insulator continuously from the upper prechamber into a lower region under the base and the lower region is either a lower prechamber or is arrangeable directly in the combustion chamber. An earth electrode is disposed in the lower region such that a lower air-surface gap spark gap is formed between the earth electrode and the electrically conductive element or the slot.

A plasma assisted spark ignition system includes an ignitor and a power supply. The first ignitor includes: a casing having a first end, a second end that forms a first electrode, and a longitudinally extending passage, a second electrode which protrudes longitudinally outward from an opening at the second end of the casing and laterally spaced inwardly to form a spark gap, and an electrical insulator (dielectric) surrounding a portion of the second electrode, and which has a terminus that is at least closely spaced to an interior surface of the end of the casing. The power supply supplies a plurality of voltage pulses to the ignitor per ignition event to generate a flash over on the dielectric. Subsequent pulses in an ignition event may be at lower amplitude than an initial pulse in the ignition event. Pulses may, for example, have a duration on the order of a nanosecond.

A plasma jet plug includes a rod-shaped central electrode, an insulator having an axial hole, a metal shell disposed around the insulator, an orifice electrode electrically connected to the metal shell and located at a distal end side of the insulator, and a gasket that contacts an outer surface of the insulator and an inner surface of the metal shell. The insulator includes a first member, a second member and an inorganic seal layer. The first member has the axial hole and includes a large-diameter portion and a small-diameter portion. The second member has a through hole into which the small-diameter portion is inserted. The second member has an outer surface that contacts the gasket. The inorganic seal layer seals a gap between the first member and the second member. In a section including the axis, the sum of seal lengths is greater than or equal to 3 mm.

An ignition device includes a center electrode, a center dielectric covering the center electrode, a ground electrode disposed so as to form a discharge space with the center dielectric, and a high energy source for applying an AC voltage between the center electrode and the ground electrode to generate a streamer discharge. A distal end portion of the center electrode projects beyond a distal end of the ground electrode to an inside of the combustion chamber of an internal combustion engine to make a dielectric discharge portion. The ground electrode is formed with an airflow inlet and en airflow outlet at a lateral portion thereof for enabling an in-cylinder airflow to be introduced into the discharge space. A distal end portion of the ground electrode projects radially inward to make a ground electrode projecting portion so that a discharge space narrow portion is formed with the dielectric discharge portion.

An ignition device includes a center electrode, a center dielectric covering the center electrode, a ground electrode disposed so as to form a discharge space with the center dielectric, and a high energy source for applying an AC voltage between the center electrode and the ground electrode to generate a streamer discharge. A distal end portion of the center electrode projects beyond a distal end of the ground electrode to an inside of the combustion chamber of an internal combustion engine to make a dielectric discharge portion. The ground electrode is formed with an airflow inlet and en airflow outlet at a lateral portion thereof for enabling an in-cylinder airflow to be introduced into the discharge space. A distal end portion of the ground electrode projects radially inward to make a ground electrode projecting portion so that a discharge space narrow portion is formed with the dielectric discharge portion.

A combustor for a gas turbine engine includes a combustion chamber and a fuel igniter assembly. The combustion chamber is defined by an annular inner combustor liner and an annular outer combustor liner. The fuel igniter assembly is coupled to the combustor and extends radially outward from the outer combustor liner. The fuel igniter assembly includes an igniter housing configured to house a fuel igniter therein, and a heat-dissipating element coupled to the igniter housing. The heat-dissipating element includes a plurality of fins configured to dissipate heat from the fuel igniter assembly.

A combustor for a gas turbine engine includes a combustion chamber and a fuel igniter assembly. The combustion chamber is defined by an annular inner combustor liner and an annular outer combustor liner. The fuel igniter assembly is coupled to the combustor and extends radially outward from the outer combustor liner. The fuel igniter assembly includes an igniter housing configured to house a fuel igniter therein, and a heat-dissipating element coupled to the igniter housing. The heat-dissipating element includes a plurality of fins configured to dissipate heat from the fuel igniter assembly.