Abstract: The invention provides a system and method for controlling corona discharge. A driver circuit provides energy to the corona igniter and detects any arc formation. Optionally, in response to each arc formation, the energy provided to the corona igniter is shut off for a short time to dissipate the arc. Once the arc dissipates, the energy is applied again to restore the corona discharge. The driver circuit obtains information relating to the corona discharge, such as timing and number of arc formations. A control unit adjusts the energy provided to the corona igniter, shut-off time, or the duration of the corona event based on the information. The adjusted energy levels and duration are applied during subsequent corona events. For example, the voltage level could be reduced or the shutoff time could be increased to limit arc formations and increase the size of the corona discharge during the subsequent corona events.

Abstract: A spark plug assembly has a ceramic insulator with a metal outer shell surrounding at least a portion of the insulator. A ground electrode is operatively attached to the outer shell and a center electrode having an elongate body extends through the insulator. The center electrode and the ground electrode provide a spark gap. A force sensor is received about the insulator. An annular inner shell is received between the outer shell and the insulator, wherein the inner shell has a surface configured to confront the insulator along an axial direction.

Abstract: A spark plug and method of construction is provided. The spark plug has a generally annular ceramic insulator extending between a terminal end and a nose end. A conductive shell surrounds at least a portion of the ceramic insulator and a ground electrode having a ground electrode sparking surface is operatively attached to the shell. An elongate center electrode has a body extending between opposite ends. The body of the center electrode is formed of a compacted and sintered conductive or semi-conductive ceramic material. The ceramic material of the body comprises at least one oxide. For example, the body of the center electrode can be formed of a perovskite structure or a spinel structure.

Abstract: An electrode material for use with spark plugs and other ignition devices. The electrode material is a two-phase composite material that includes a matrix component and a dispersed component embedded in the matrix component. In a preferred embodiment, the matrix component is a precious-metal based material and the dispersed component includes a material that exhibits a high melting point and a low work function such as, for example, carbides, nitrides, and/or intermetallics. A process for forming the electrode material into a spark plug electrode is also provided.

Abstract: A spark plug (20) for igniting a mixture of fuel and air of an internal combustion engine comprises a center electrode (22) and a ground electrode (24). At least one of the electrodes (22, 24) includes a body portion (28, 30) formed of thermally conductive material and a firing tip (32, 34) disposed on the body portion (28, 30). The firing tip (32, 34) includes a ceramic material, providing an exposed firing surface (36, 38). The ceramic material is an electrically conductive, monolithic ceramic material. The ceramic material of the firing tip (32, 34) includes at least one perovskite structure and/or at least one a spinel structure.

Abstract: A system and method for detecting arc formation in a corona discharge ignition system is provided. The system includes a driver circuit conveying energy oscillating at a resonant frequency; a corona igniter for receiving the energy and providing a corona discharge; and a frequency monitor for identifying a variation in an oscillation period of the resonant frequency, wherein the variation in the oscillation period indicates the onset of arc formation. The method includes supplying the energy to the driver circuit and to the corona igniter; obtaining the resonant frequency of the energy in the oscillating driver circuit; and identifying a variation in the oscillation period of the resonant frequency.

Abstract: A lighting assembly for a vehicle, and in particular, an interior lighting assembly having a reduced profile using solid state illuminators is provided along with a method of construction thereof. The assembly includes a housing; a lens attached to the housing; a printed circuit board disposed between the housing and the lens; at least one light source attached in operable electrical communication to the printed circuit board; and a light blade. The light blade has opposite sides disposed between the printed circuit board and the lens. One of the sides has a first configuration of optics and the other of the sides has a second configuration of optics, wherein the first and second configurations of optics are different from one another.

Abstract: A method of manufacturing an electrode material for use in spark plugs and other ignition devices. The electrode material may be manufactured into a desirable form by hot-forming a layered structure that includes a ruthenium-based material core, an iridium-based interlayer disposed over an exterior surface of the ruthenium-based material core, and a nickel-based cladding disposed over an exterior surface of the iridium-based material interlayer. The elongated layered wire produced by the hot-forming then has its nickel-based cladding removed to derive an elongated electrode material wire that includes the ruthenium-based material core encased in the iridium-based material. The elongated electrode material wire can be used to make many different spark plug/ignition device components.

Abstract: A spark plug includes a metallic shell, an insulator, a center electrode, a ground electrode, and a thin firing pad. The thin firing pad is made from a noble metal and can be attached to the center electrode, the ground electrode, or to both. In some examples, the thin firing pad possesses certain geometric properties and relationships that can improve ignitability and durability of the thin firing pad.

Abstract: A capacitive discharge welding method is used to join firing tips, such as those made from various precious metals, to spark plug electrodes. In one embodiment, charged capacitors or other energy storage devices coupled to welding electrodes quickly release stored energy so that a peak weld power and maximum interface temperature is quickly established, followed by a rapid decline in weld power and interface temperature. The resulting capacitive discharge weld joint may include solidified molten material from both the firing tip and the electrode and possess a number of other desirable qualities.

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 spark plug having a spark plug body, a center electrode, and a rod-shaped ground electrode that is attached to a front end of the spark plug body and has an electrode end section with an end surface and two side surfaces. The electrode end section is provided with a step onto which is attached a precious metal component with an ignition surface that, together with the center electrode, forms a spark air gap. The step formed in the electrode end section and the precious metal component attached thereto extend across the entire width (B) of the electrode end section so that the precious metal component is flush with the electrode end section on the two sides surfaces, as well as the end surface.

Abstract: An electrode core material that may be used in electrodes of spark plugs and other ignition devices to provide increased thermal conductivity to the electrodes. The electrode core material is a precipitate-strengthened copper alloy and includes precipitates dispersed within a copper (Cu) matrix such that the electrode core material has a multi-phase microstructure. In several exemplary embodiments, the precipitates include: particles of iron (Fe) and phosphorous, particles of beryllium, or particles of nickel and silicon.

Abstract: A ceramic insulator for surrounding an electrode of an ignition device, such as a corona igniter or spark plug, is provided. The insulator is formed of a ceramic material including alumina in an amount of 28 to 38 wt. %, silica in an amount of 57 to 67 wt. %, and calcium oxide in an amount of 3 to 7 wt. %, based on the total weight of the ceramic material. The ceramic insulator is typically formed by firing a mixture of Kaolin, calcium carbonate, and silica, wherein the calcium carbonate acts as a flux during firing. The ceramic material has a relative permittivity of about 5.5 to 6.5 and thus improves the electrical efficiency of the ignition device. The ceramic material is also capable of withstanding temperatures of 900 to 1000° C. and has excellent thermal shock resistance, making it suitable for use in internal combustion engines.

Abstract: A spark plug has a metal shell, an insulator, a center electrode, and a ground electrode. One or more firing tips can be attached to the center electrode, to the ground electrode, or to both electrodes. The metal shell and ground electrode are attached together by way of one or more laser keyhole welds at an interface of the shell and electrode. Before the laser keyhole welds, resistance welding can be executed for a temporary attachment.

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 (el) 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: A spark plug has a shell, an insulator, a center electrode, a ground electrode, and a firing pad. The firing pad is made of a precious metal material and is attached to the ground electrode. The firing pad has a side surface at a peripheral edge that can be flush or nearly flush with a free end surface of the ground electrode. This construction can help improve ignitability and flame kernel growth of the spark plug during a sparking event, and can provide better thermal management at the attached ground electrode and firing pad.

Abstract: An igniter (20) includes an outer insulator (24) formed of an outer ceramic material hermetically sealed to a conductive core (26). The conductive core (26) is formed of a core ceramic material and a conductive component, such as an electrically conductive coating applied to the core ceramic material or metal particles or wires embedded in the core ceramic material. The conductive core (26) is typically sintered and disposed in the green outer insulator (24). The components are then sintered together such that the outer insulator (24) shrinks onto the conductive core (26) and the hermetic seal forms therebetween. The conductive core (26) fills the outer insulator (24), so that the conductive core (26) is disposed at an insulator nose end (34) of the outer insulator (24) and the electrical discharge (22) can be emitted from the conductive core (26), eliminating the need for a separate firing tip.

Abstract: An industrial spark plug (20) includes a central electrode (24) with a central base (30) formed of a nickel-based material and a central firing tip (32) formed of an iridium-based material. The central firing tip (32) has a tip thickness (tct) of 0.02 to 0.03 inches, a tip diameter (dct) of 0.1184 to 0.1776 inches, and an aspect ratio of 4.736 to 7.104. The central firing tip (32) is electron beam welded to the central base (30) to provide a robust joint therebetween. The central electron beam weld (36) includes a mixture of re-crystallized iridium-based material and re-crystallized nickel-based material extending continuously along and over the entire welding interface. The spark plug (20) also includes a ground electrode (26) with a ground firing tip (38) electron beam welded to a ground base (42).

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.