| 摘要 |
PURPOSE:To check abnormal consumption in a center electrode, by connecting the center electrode terminal of a spark plug to the condenser interposed between an earth and the terminal at a time when ignitability in an air-fuel mixture is poor, and increasing an extent of capacity discharge energy, while separating the condenser from the center electrode terminal when the ignitability is favorable. CONSTITUTION:When ignitability in an air-fuel mixture grows worse in the engine running state detected by a running state detector 15, an on-off contact 14 is closed by an on-off control part 16, and a condenser 12 is connected to a center electrode terminal 11 of a spark plug 10 at a grounding gap. With this connection, capacity discharge energy is increased to some extent, raising a degree of ignition ability so high, and every such an air-fuel mixture as being poor in ignitability is ignited without fail. On the other hand, when the detected engine running state comes into a state of being favorable in the mixture ignitability, the condenser 12 is separated from the center electrode terminal 11 of the spark plug 10 at the grounding gap. With this constitution, both charging and discharging of the condenser 12 are stopped, and discharging by means of ordinary discharge energy takes place, thus a temperature rise in a center electrode of the spark plug 10 is checked. |
