| 摘要 |
<p>An ECU performs correction so that a fuel addition interval is reduced as the amount of variation in backpressure increases, the correction being based on the amount of variation in current backpressure relative to basic backpressure obtained when a basic addition interval is set (Steps ST1-ST4). By this, even if the pressure in an exhaust path where a fuel addition valve is placed is raised to increase the backpressure at an ejection hole portion of the fuel addition valve, a required fuel addition amount can be secured. This achieves sufficient rise of catalyst bed temperature necessary for an exhaust gas purification effect of a catalyst. Also, the temperature of the tip of the fuel addition valve can be maintained equal to or below a predetermined value (temperature at which creation of deposit is suppressed), so that clogging of the ejection hole by deposit can be prevented.</p> |
