| 摘要 |
PROBLEM TO BE SOLVED: To restrain the exhaust quantity of NOx from being increased when a fuel-cut operation is shifted to a lean burn operation, and maintain excellent exhaust gas characteristics. SOLUTION: This control device allows a rich burn accelerating flag FRICH to be set at [1] (S29 and S30) during the period of time for rich burn acceleration TRICH when a deceleration fuel cutting condition is satisfied (S24), when a lean burn operation is in operation (S28), an air-fuel ratio is set at a position closer to the rich burn side rather than that of a stoichiometric air-fuel ratio. After the period of time for rich burn acceleration TRICH has elapsed since a deceleration fuel cut operating condition was established, operations are shifted to a fuel-cut operation (S29 and S32). During the period of the time for rich burn acceleration, NOx is absorbed by NOx absorbent so as to allow NOx to be reduced.
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