| 摘要 |
When an operating condition including load and speed of an internal combustion engine (1) is in a prescribed low-speed high-load region (an energy suppression region A) having a possibility causing pre-ignition, energization time TDWLMIN for the energy suppression region is selected as an energization time for a primary coil (22a). In other normal regions, normal energization time TDWL is selected. Normal energization time TDWL has a characteristic such that the normal energization time shortens, as the engine speed increases. In a low speed region, a given energization time that can fulfil a discharge energy required in a high exhaust gas recirculation region is provided. Energization time TDWLMIN for the energy suppression region A is constant regardless of engine speeds and relatively short, and is set to a level such that a coil generated maximum voltage does not exceed a withstand voltage of a spark plug (9) even when no-discharge occurs due to pre-ignition. |
