摘要 |
The spark plug comprises an outer shell (1), a central electrode (2), an insulator (3) surrounding the central electrode (2) and at least one ground electrode (4B) connected at at least one point to the outer shell (1). At least one (4B) of the electrodes consists of an outer layer made of a corrosion resistant material (e.g. nickel or a nickel alloy) and of an inner core made of a material having good thermal conductivity characteristics and a good corrosion and erosion resistance (e.g. silver or a silver alloy). In front of the bottom end of the other electrode (2), i.e. at the spark gap (5) the inner core projects through the outer layer perpendicularly to the longitudinal axis of said one electrode (4B). Several embodiments of the spark plug as well as several methods for making the electrodes of the spark plug are described. |