SURFACE-DISCHARGE SPARK PLUG Russian patent published in 2001 - IPC

FIELD: internal-combustion engines primarily those using high degree of boosting. SUBSTANCE: spark plug has metal body accommodating coaxially mounted ceramic insulator with discharge surface on its face part and central electrode. Face part of insulator is arranged in a spaced relation to body and has prebreak-down surface conductivity higher than conductivity of surrounding fuel-air mixture and post-breakdown conductivity below the latter; electromagnetic field concentrator is provided in body. Discharge surface of face part is located in one plane below or above face surface of body. Face part of insulator is impregnated with compound based on metal oxides and/or carbides, or it is covered with catalytic coating. Electromagnetic field concentrator is made in the form of projections and/or depressions and may be provided, in addition, with current-conducting member to extend service life of spark plug. Proposed spark plug provides for no-break sparking due to enlarged spark gap and provision for self-removal of carbon deposit. EFFECT: augmented fuel-air mixture ignition process constant breakdown voltage. 19 cl, 22 dwg