| 摘要 |
<p>A spark plug (60, Fig. 4) for an internal combustion engine comprises a ceramic body (31) and a plurality (e.g. three) of spark electrodes (34) which receive high-tension electricity independently of each other via electrical conductors extending through the ceramic body. Each spark electrode (34) has a tip region which extends away from the plug axis in the vicinity of the end of the plug so as to define with a respective counter-electrode (40) of the plug a spark-gap (42) which is substantially parallel to the axis of the plug. Preferably the spark gaps (42) are substantially equiangularly spaced around the plug axis. The spark plug of the invention enables an internal combustion engine to be operated with increased thermal efficiency compared to a conventional single-gap plug, and with an improved fuel economy which increases as the air-fuel ratio increases, whereby the engine may be operated on a fuel of reduced octane number (e.g. with low lead or lead-free gasoline) and or with an increased compression ratio.</p> |
