| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To restrain degradation in fuel economy and catalyst deterioration accompanied with detoxification treatment, by accurately estimating a deposit amount of sulfur to a NOx trap catalyst. <P>SOLUTION: A gasoline fuel is determined to be high-octane gasoline or regular gasoline by an ignition timing control based on a detection of knocking. When an estimate sulfur deposit amount SOXMILE is calculated in proportion to a mileage, a coefficient HOSGAS determining increasing speed of the estimate sulfur deposit amount SOXMILE with respect to the mileage is set to a different value based on whether a fuel used at this time is the high-octane gasoline or the regular gasoline. When the estimate sulfur deposit amount SOXMILE becomes more than an allowable value SOXFUL, an exhaust temperature is increased by being rich of air-fuel ratio, delay angle correction of an ignition timing, and stopping of exhaust reflux, whereby sulfur is released from the catalyst. <P>COPYRIGHT: (C)2003,JPO</p> |
