Abstract: This invention provides a corona discharge fuel igniter system and methods for igniting fuel in an internal combustion engine. A ceramic dielectric material is provided that significantly increases the efficiency of corona discharge to ignite the fuel in an internal combustion engine.

Abstract: A spark plug (24) of an internal combustion engine is provided with an integrated capacitor feature to increase the intensity of its spark. The capacitor feature is formed by applying metallic film (62, 64) to the inner (30) and outer surfaces of a tubular insulator (26). The insulator (26) forms a dielectric and sustains an electrical charge when an electrical differential is established between the inner (64) and outer (62) metallic films. The stored electrical charge is discharged with the firing of a spark. The metallic films can be applied as a paint or ink directly to the surfaces of the insulator (26), or can be mixed with a glazing compound to form conductive coatings simultaneous with the glazing operation. Ganged (62?) or serpentine (62?) micro-plates can be formed within either or both of the inner and outer metallic films to increase the charge-carrying surface area.

Abstract: A spark plug (20) includes a center electrode (24) and a ground electrode (22). The electrodes (22, 24) include a core (26) formed of a copper (Cu) alloy and a clad (28) formed of a nickel (Ni) alloy enrobing the core (26). The Cu alloy includes Cu in an amount of at least 98.5 weight percent, and at least one of Zr and Cr in an amount of at least 0.05 weight percent. The Cu alloy includes a matrix of the Cu and precipitates of the Zr and Cu dispersed in the Cu matrix. The Ni alloy of the clad (28) includes Ni in an amount of at least 90.0 weight percent. The Ni alloy also includes at least one of a Group 3 element, a Group 4 element, a Group 13 element, chromium (Cr), silicon (Si), and manganese (Mn) in a total amount sufficient to affect the strength of the Ni alloy.

Abstract: A corona igniter 20 with improved temperature control at the firing end is provided. The corona igniter 20 comprises a central electrode 24 include a core material 30, such as copper, surrounded by a clad material 32, such as nickel. The core material 30 extends longitudinally between an electrode terminal end 34 and an electrode firing end 36. The core material 30 is disposed at the electrode terminal end 34 and has a core length Ic equal to at least 90% of an electrode length Ie of the central electrode 24. At least 97% of the core length Ic is surrounded by an insulator 26. The electrode diameter is increased, such that a clad thickness tcl of the central electrode 24 is equal to at least 5% of an insulator thickness ti, and a core diameter Dc is equal to at least 30% of the insulator thickness ti.

Abstract: A spark plug, center electrode and method of construction is provided. The spark plug has a generally annular ceramic insulator and a conductive shell surrounding at least a portion of the ceramic insulator. A ground electrode is operatively attached to the shell, with the ground electrode having a ground electrode sparking surface. A center electrode has an elongate body with a center electrode sparking surface. The center electrode sparking surface and the ground electrode sparking surface provide a spark gap. The center electrode body is constructed of a composite material including at least one ceramic material.

Abstract: A corona igniter 20 includes an insulator 28 surrounding a central electrode 24 and a shell 30 surrounding the insulator 28. The shell 30 presents a shell gap 38 having a shell gap width ws between a shell lower end 34 and a shell inner surface 90 or shell outer surface 92. The shell 30 has a shell thickness is decreasing toward the shell lower end 34 allowing the shell gap width ws to increase toward the shell lower end 34. The shell gap 38 is open at the shell lower end 34 allowing air to flow therein, and the shell gap width ws is greatest at the shell lower end 34. The increasing shell gap width ws enhances corona discharge 22 along the insulator 28 between the central electrode 24 and shell 30.

Abstract: A spark plug (20) includes a center electrode (24) and a ground electrode (22). The electrodes (22, 24) include a core (26) formed of a copper (Cu) alloy and a clad (28) formed of a nickel (Ni) alloy enrobing the core (26). The Cu alloy includes Cu in an amount of at least 98.5 weight percent, and at least one of Zr and Cr in an amount of at least 0.05 weight percent. The Cu alloy includes a matrix of the Cu and precipitates of the Zr and Cu dispersed in the Cu matrix. The Ni alloy of the clad (28) includes Ni in an amount of at least 90.0 weight percent. The Ni alloy also includes at least one of a Group 3 element, a Group 4 element, a Group 13 element, chromium (Cr), silicon (Si), and manganese (Mn) in a total amount sufficient to affect the strength of the Ni alloy.

Abstract: A spark plug (24) is used in an ignition system (10) of the type for creating a precisely timed spark to ignite an air/fuel mixture in an internal combustion engine. The spark plug (24) is provided with an integrated capacitor feature to increase the intensity of its spark. The capacitor feature is formed by applying metallic film (62, 64) to the inner (30) and outer surfaces of a tubular insulator (26). The insulator (26), made from an alumina ceramic material, forms a dielectric and sustains an electrical charge when an electrical differential is established between the inner (64) and outer (62) metallic films. The stored electrical charge is discharged with the firing of a spark in the spark gap (54). The inner (64) and outer (62) metallic films can be applied as a paint or ink directly to the surfaces of the insulator (26), or can be mixed with a glazing compound to form conductive coatings simultaneous with the glazing operation.

Abstract: A spark plug electrode material that may be used in spark plugs and other ignition devices including industrial plugs, aviation igniters, glow plugs, or any other device that is used to ignite an air/fuel mixture in an engine. According to an exemplary embodiment, the electrode material includes a refractory metal (for example, tungsten (W), molybdenum (Mo), rhenium (Re), ruthenium (Ru) and/or chromium (Cr)) and a precious metal (for example, rhodium (Rh), platinum (Pt), palladium (Pd) and/or iridium (Ir)), where the refractory metal is present in an amount that is greater than that of the precious metal. This includes, but is certainly not limited to, electrode materials including tungsten-based alloys such as W—Rh and ruthenium-based alloys such as Ru—Rh. Other combinations and embodiments are also possible.

Abstract: A corona igniter 20 includes an electrode gap 28 between the central electrode 22 and the insulator 32 and a shell gap 30 between the insulator 32 and the shell 36. The gaps 28, 30 are filled with a filler material 40 to prevent corona discharge 24 in the gaps 28, 30 and to concentrate the energy at a firing tip 58 of the central electrode 22. The filler material 40 may be electrically insulating or conductive. The shell gap width ws may be greatest at a shell lower end 92. The shell gap 30 may also be in a turnover region between a shell upper end 44 and the insulator 32, in which case the filler material 40 is injection molded around the turnover region. During operation of the igniter 20, the filler material 40 provides a reduced voltage drop across the gap 28, 30.

Abstract: A corona ignition system for providing a corona discharge (24) includes an igniter (20) having an electrode (26) with an asymmetrical firing tip (28) relative to an electrode center axis (ae). The firing tip (28) includes a first surface area (A1) facing the fuel injector (42) which is greater than a second surface area (A2) facing a cylinder block (32). The first surface area (A1) presents a projection (60) having a sharp edge, and the second surface area (A2) presents a round outward surface (62). Accordingly, a radio frequency electric field emitted from the first surface area (A1) provides a robust corona discharge (24) in a flammable area at an outside edge (30) of the fuel spray. No electric field is emitted from the second surface area (A2), and no power arcing occurs between the second surface area (A2) and the cylinder block (32).

Abstract: A corona igniter 20 includes an electrode gap 28 between the central electrode 22 and the insulator 32 and a shell gap 30 between the insulator 32 and the shell 36. An electrically conductive coating 40 is disposed on the insulator 32 along the gaps 28, 30 to prevent corona discharge 24 in the gaps 28, 30 and to concentrate the energy at a firing tip 58 of the central electrode 22. The electrically conductive coating 40 is disposed on an insulator inner surface 64 and is spaced radially from the electrode 22. The electrically conductive coating 40 is also disposed on the insulator outer surface 72 and is spaced radially from the shell 36. During operation of the igniter 20, the electrically conductive coating 40 provides a reduced voltage drop across the gaps 28, 30 and a reduced electric field spike at the gaps 28, 30.

Abstract: A corona igniter (20) for emitting a radio frequency electric field and providing a corona discharge (24) includes a central electrode (22) at a positive voltage, a grounded metal shell (30), and an insulator (28) with an abruption (34) extending radially outward relative to the central electrode (22). The abruption (34) is typically an increase of at least 15% of a local thickness (t) of the insulator (28) over less than 25% of a nose length (1) of an insulator nose region (74). The abruption (34) is typically one flank (82) of a protrusion or a notch, and the flank (82) faces the shell (30). The abruption (34) reverses the electric field and voltage potential gradient along the insulator outer surface (32), repels charged ions away from the insulator (28), and thus prevents the formation of a conductive path between the central electrode (22) and the shell (22).

Abstract: The invention relates to a corona ignitor device configured to be fixed within a combustion chamber, including a housing extending between an upper end and a lower end of the ignitor device. Inductor windings are received in the housing between the upper and lower ends, and a magnetic shield located between the housing and the inductor windings prevent magnetic flux from emanating out of the ignitor device.

Abstract: A corona igniter (20) includes an ignition coil (26) providing a high voltage energy to an electrode. The coil (26) is disposed in a housing (34) and electrically isolated by a coil filler (36) and a capacitance reducing component (38) which together improve energy efficiency of the system. The coil filler (36) includes an insulating resin permeating the coil (26). The capacitance reducing component (38) has a permittivity not greater than 6, for example ambient air, pressurized gas, insulating oil, or a low permittivity solid. The capacitance reducing compound (38) surrounds the coil (26) and other components and fills the remaining housing volume. The coil filler (36) has a filler volume and the capacitance reducing component (38) has a component volume greater than the filler volume.

Abstract: An ignitor assembly constructed in accordance with one aspect of the invention has an upper inductor subassembly coupled to a lower firing end subassembly for relative pivot movement between the subassemblies. The upper inductor subassembly includes a tubular housing with inductor windings received therein with an upper electrical connector adjacent an upper end of the housing and a lower electrical connector adjacent a lower end of the housing. The lower firing end subassembly includes a ceramic insulator and a metal housing surrounding at least a portion of the ceramic insulator. The ceramic insulator has an electrical terminal extending from a terminal end and an electrode extending from a firing end. A flexible tube couples the upper inductor subassembly to the lower firing end subassembly and maintains the electrical terminal of the lower firing end subassembly in electrical contact with the lower electrical connector of the upper at a pivot joint.

Abstract: A corona discharge ignition system 20 includes an igniter 22 for receiving pulses of electrical energy each having a radio frequency. The igniter 22 emits pulses of electrical field ionizing a fuel-air mixture and providing pulses of corona discharge 24, rather than a continuous, un-pulsed corona discharge over the same period of time. The system 20 includes at least one power supply 48, 50 providing the electrical energy to a corona drive circuit 52 and ultimately to the igniter 22. The system 20 can include a variable high voltage power supply 50 and a local charge storage device 70 for providing pulses of the electrical energy to the corona drive circuit 52. The system 20 provides a robust ignition comparable to a single event corona discharge ignition system, with improved resistance to arc formation, while using a fraction of the energy.

Abstract: An igniter (20) of a corona ignition system emits a non-thermal plasma in the form of a corona (30) to ionize and ignite a fuel mixture. The igniter (20) includes an electrode (32) and a ceramic insulator (22) surrounding the electrode (32). The insulator (22) surrounds a firing end (38) of the electrode (32) and blocks the electrode (32) from exposure to the combustion chamber (28). The insulator (22) presents a firing surface (56) exposed to the combustion chamber (28) and emitting the non-thermal plasma. A plurality of electrically conducting elements (24) are disposed in a matrix (26) of the ceramic material and along the firing surface (56) of the insulator (22), such as metal particles embedded in the ceramic material or holes in the ceramic material. The electrically conducting elements (24) reduce arc discharge during operation of the igniter (20) and thus improve the quality of ignition.

Abstract: An ignitor assembly constructed in accordance with one aspect of the invention has an upper inductor subassembly coupled to a lower firing end subassembly for relative pivot movement between the subassemblies. The upper inductor subassembly includes a tubular housing with inductor windings received therein with an upper electrical connector adjacent an upper end of the housing and a lower electrical connector adjacent a lower end of the housing. The lower firing end subassembly includes a ceramic insulator and a metal housing surrounding at least a portion of the ceramic insulator. The ceramic insulator has an electrical terminal extending from a terminal end and an electrode extending from a firing end. A flexible tube couples the upper inductor subassembly to the lower firing end subassembly and maintains the electrical terminal of the lower firing end subassembly in electrical contact with the lower electrical connector of the upper at a pivot joint.