Spark plug for an internal-combustion engine

摘要

The spark plug (2) has a hollow screw-in socket (3) with an internally located tubular earth electrode (6), a hollow insulator (7), a supporting stud (8) which is anchored therein, and a plurality of electrodes (9, 10) which are attached to the supporting stud (8) and are at distances from the common earth electrode (6) which are intended for the formation of ignition sparks. The electrodes (10) are of pin-like construction. The supporting stud (8) is of tubular construction and holds capillaries (16) and a medium (17) which can be vaporised, possibly as well as a gas (18), and forms a so-called heat tube which protects the supporting stud (8) and electrodes (9, 10) attached to it against excessive heating which would trigger glow discharges. However, this heat tube (8, 16, 17, 18) also results in the operating temperature of the electrodes (9, 10) being reached quickly. That one of the electrodes (9) which is at the greatest distance from the insulator (7) is constructed as a guide body (19) and gives a helical flow behaviour to a mixture having excess air flowing into the spark plug, which helical flow behaviour causes fuel enrichment, for reliable ignition, along the earth electrode (6). <IMAGE>