| 摘要 |
<P>PROBLEM TO BE SOLVED: To speedily realize a target exhaust air-fuel ratio without being followed by torque fluctuation in changing exhaust air-fuel ratio from lean to rich by reducing intake air quantity for regenerating an NOx trap catalyst disposed on an exhaust passage. <P>SOLUTION: A direct injection type fuel injection means capable of conducting post-injection in small quantity after main injection is used, and post-injection is conducted in accordance with retardation of an actual value to a target value of intake air quantity in changing from lean to rich. The larger the retardation is, the larger the post-injection quantity is set. Post- injection timing is retarded as well. The larger the retardation is, the smaller the main injection quantity is set. <P>COPYRIGHT: (C)2004,JPO |
