Abstract: A spark plug and method of manufacturing, where the spark plug meets particular geometric relationships to maintain and potentially improve dielectric performance while downsizing other plug dimensions. The spark plug includes an insulator that can withstand higher voltages while having areas with a reduced cross-sectional thickness. In some embodiments, the insulator has a dielectric strength of 42 kV/mm or more with a radial thickness at the internal seal of 1.5 to 1.6 mm, inclusive, and a radial thickness at a gasket of 0.6 to 0.9 mm, inclusive.

Abstract: An electrode material for a spark plug includes 22-46 wt % iron (Fe), inclusive, 20-40 wt % nickel (Ni), inclusive, 13-42 wt % cobalt (Co), inclusive, and one or more additional elements selected from aluminum (Al), titanium (Ti), chromium (Cr), boron (B), and niobium (Nb), wherein the electrode material has a coefficient of thermal expansion (CTE) from room temperature to 200° C. that is less than or equal to 11.0×10?6/° C. In another example, the electrode material includes greater than or equal to 32 wt % iron (Fe), greater than or equal to 36 wt % nickel (Ni), and one or more additional elements selected from aluminum (Al), chromium (Cr), and cobalt (Co). In advantageous embodiments, the electrode material includes greater than or equal to 22 wt % cobalt (Co). Replacing nickel with a higher percentage of cobalt can help reduce the coefficient of thermal expansion (CTE) of the electrode material.

Abstract: A prechamber spark plug that includes an internal reservoir, a flow passage portion, and a prechamber and is designed to operate efficiently across a wide variety of operating conditions and ranges. The internal reservoir includes upper and lower internal reservoir sections, the prechamber includes upper and lower prechamber sections, and the flow passage portion fluidly connects the lower internal reservoir section and the upper prechamber section so that burnt air/fuel gases can be exchanged therebetween. A ground electrode assembly with a ground electrode ring may be positioned in the prechamber such that it separates the upper and lower prechamber sections, whereas a modular prechamber cap may be used to define the shape and size of the lower prechamber section. In one example, the flow passage portion has a total cross-sectional area (AFC) and the internal reservoir has a total volume (VRES), and the ratio AFC:VRES is greater than or equal to 0.015 (1/mm).

Abstract: A pre-chamber spark plug includes a shell extending along a longitudinal axis and comprising an inner surface. The pre-chamber spark plug further includes an insulator including an outer surface. The pre-chamber spark plug further includes a pre-chamber cap connected to the shell. The pre-chamber cap and the shell together forms a pre-chamber. The pre-chamber spark plug further includes an annular reservoir defined between the outer surface of the insulator and the inner surface of the shell. The annular reservoir is spaced apart from the pre-chamber with respect to the longitudinal axis. The pre-chamber spark plug further includes a plurality of projections disposed between the annular reservoir and the pre-chamber with respect to the longitudinal axis. The plurality of projections at least partially define a plurality of flow passages therebetween.

Abstract: A metal shell for a spark plug is made from a steel material that has increased carbon content and, in some embodiments, boron as well. The steel material is well-suited for extrusion because of its ductility, while maintaining requisite strength. The spark plug shell may have a reduced outer diameter (ODHL) at a crimped hot lock region, such as the case when the shell is used in smaller diameter spark plugs, such as M8 and M10 plugs. According to a non-limiting example, the spark plug shell steel material comprises 0.20-0.55 wt % carbon, inclusive.

Abstract: A spark plug having a shell with a ground electrode recess. A ground electrode having an insertion end, a firing end, and a round cross-sectional profile toward the insertion end is inserted into the ground electrode recess of the shell. An attachment portion surrounds at least a portion of the ground electrode and includes a solidified bonding material at a connection interface between the ground electrode and the shell. In some implementations, the ground electrode can have a copper core that extends further into the shell, past the distal end of the insulator. In some embodiments, the ground electrode has a sheath surrounding the copper core that has aluminum and a high weight percentage of nickel.

Abstract: A spark plug, including a metallic shell, an insulator, a center electrode, and a ground electrode. The insulator includes a first outer surface at least partly along an exposed portion and a second outer surface at least partly along an unexposed portion. The first outer surface extends between the exposed-unexposed interface to a tip merge portion adjacent a distal end of the insulator. The first outer surface and the second outer surface meet at a nose surface transition. At the nose surface transition, the first outer surface is disposed at a first angle with respect to a central axis of the spark plug, and the second outer surface is disposed at a second angle with respect to the central axis of the spark plug. The first angle is larger than the second angle, and the nose surface transition is located within the unexposed portion or at the exposed-unexposed interface.

Abstract: A corona igniter (20) includes a metal shell (32) with a corona reducing lip (38) spaced from an insulator (26) and being free of sharp edges (40) to prevent arcing (42) in a rollover region and concentrate the electrical field at an electrode firing end (48). The corona reducing lip (38) includes lip outer surfaces (88) being round, convex, concave, or curving continuously with smooth transitions (90) therebetween. The corona reducing lip (38) includes lip outer surfaces (88) presenting spherical lip radii (rl) being at least 0.004 inches. The corona igniter (20) also includes shell inner surfaces (104) and insulator outer surfaces (75) facing one another being free of sharp edges (40).

Abstract: A spark plug suppressor and a method of producing a spark plug suppressor from a suppressor precursor liquid that may be cured at a temperature below 300° C. The spark plug suppressor may include particles or grains dispersed in a matrix of electrically conducting material, electrically semiconducting material, or electrically non-conducting material. The suppressor may include a conductive glass seal component and a resistive suppressor component. The resistive suppressor component may be at least partially embedded in the glass seal component, and the glass seal component may seal a center electrode of the spark plug, a terminal of the spark plug, or both the center electrode and the terminal.

Abstract: A corona igniter assembly 20 comprises an ignition coil assembly 22, a firing end assembly 24, and a metal tube 26 connecting the ignition coil assembly 22 to the firing end assembly 24. A rubber boot 28 is disposed in the metal tube 26 and compressed symmetrically between a coil output member 30 of the ignition coil assembly 22 and an insulator 42 of the firing end assembly 24. Thus, the rubber boot 28 fills any air gaps and provides a hermetic seal between the ignition coil assembly 22 and the firing end assembly 24 to prevent unwanted corona discharge from forming from those air gaps.

Abstract: A corona ignition system including a corona igniter, switches, and a programmable controller capable of rapidly adjusting to changes in resonant frequency is provided. Energy at a drive frequency and an output current is provided to the corona igniter. Switches provide energy to the corona igniter at the drive frequency and are activated at different times. The controller obtains the output current provided to the corona igniter, typically once every half cycle, and activates the first switch a predetermined amount of time after a first zero crossing of the output current, wherein the first zero crossing is a zero crossing of the most recent full cycle of the output current. The second switch is activated a predetermined amount of time after a second zero crossing occurring after the first zero crossing. The delay of the system is accounted for by the controller, rather than other components.