摘要 |
Decreases in the volume of intake air to an engine in response to environmental changes results in an increase in amount of PM emissions. In view of this situation, a correction coefficient of fuel supply interval is calculated based on the variation in amount of PM emissions to adjust a reference fuel supply interval in order to determine an target fuel supply interval. By adjusting the fuel supply interval, a fuel supply amount appropriate to the variation in amount of PM emissions, thereby preventing clogging of the injection hole of a supplemental fuel valve, while maintaining fuel economy. |