| 摘要 |
<p>According to the present invention, an internal combustion engine (1) is a cylinder direct injection spark-ignited internal combustion engine having a variable compression ratio mechanism (2). Based on an engine operating condition (step 1), a basic target compression ratio and a basic ignition time period are set, and the amount of oil dilution fuel mixed in oil is estimated (steps 2, 3). When the amount of oil dilution fuel is equal to or greater than a threshold (step 4), the target compression ratio is set to a high compression ratio, and an ignition time period delay correction is performed in order to avoid knocking (steps 5, 6). Due to the target compression ratio being a high compression ratio, the cylinder wall surface area exposed inside the fuel chamber is reduced during the fuel injection time period, and oil dilution caused by the mixing in of the fuel component is suppressed.</p> |
