| 摘要 |
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. 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. The metallic film (62, 64) is specially selected from materials that will not migrate into the porous matrix of the ceramic insulator (26). The metallic film (62, 64) is preferably gold, platinum, copper, or a platinum group metal. |
