| 摘要 |
<p>In a surface-discharge spark plug, in order to lengthen the path of the discharge surface with a given ignition voltage, the upper surface (22) of the insulating body (10) facing the combustion chamber is designed so that it is crossed by a plurality of field lines (30) forming parts of an electric field generated between the central electrode (21) and the insulating body (10) and the annular mass electrode (16) fitted to the metal casing (11) which surrounds the central electrode (21). Part of the electrode (16 or 21) which represents the cathode (-) is arranged at a certain distance behind the surface (22), when seen in the direction of the field lines, forming an angle with the latter surface.</p> |
