| 摘要 |
An ignition unit (11) has a superimposed voltage generation circuit (17) that feeds, between electrodes of an ignition plug (9), a superimposed voltage of the same direction as a discharge voltage, and in an operation range wherein an engine rotation speed is equal to or lower than a given speed and an engine load is equal to or lower than a given load, feeding of the superimposed voltage is carried out. Although the energization time for a primary coil (15a) is basically set in accordance with the engine rotation speed, the energization time TDWLON for the superimposed voltage feeding is set shorter than the energization time TDWLOFF for the superimposed voltage non-feeding. With this, temperature increase of the ignition unit (11) caused by the feeding of the superimposed voltage is suppressed. |
