Long-life sparking plug with radially asymmetric gaps - has earthed electrodes of rectangular section bent towards centre with angular deviation of up to 10 deg.

摘要

The earthed electrodes (4) welded to the plug casing (1) are bent towards the central electrode (3) and its insulating body (2), so that the greater surface of each earthed electrode (4) passes alongside the central electrode (3), and the underside extends parallel to the face of the casing (1). With a cross-section of e.g. 2.5 x 1.0 mm the useful area of each earthed electrode is enlarged from about 2.5 to about 6.25 sq.mm. ADVANTAGE - Degradation of spark gap width with unaltered electrode cross-section is reduced and servicing interval prolonged, without detriment to thermal properties.