| 摘要 |
In a predetermined low-temperature startup state (in a rich atmosphere), in principle, over-advanced ignition control for advancing ignition timing beyond MBT and intake-synchronized injection control for causing the entire amount of to-be-injected fuel to undergo intake-synchronized injection are executed. Thus, the peak of intra-cylinder temperature increases, and the amount of port-adhering fuel decreases, whereby the emission amount of unburnt HC can be reduced. However, when the PM emission amount exceeds a PM permissible amount, instead of the intake-synchronized injection control, there is performed processing for causing a portion of the to-be-injected fuel to undergo intake-unsynchronized injection and causing the remaining fuel to undergo intake-synchronized injection. Thus, the amount of intra-cylinder-adhering fuel decreases, and the partial oxidation reaction of the intra-cylinder-adhering fuel, which is a cause of generation of PM, is suppressed. As a result, the PM emission amount decreases, whereby the PM emission amount can be suppressed to the PM permissible amount.
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