| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an air-fuel ratio control method for an engine that enables small torque fluctuation when temporarily generating a rich condition of exhaust gas to recover a NOx occlusion capacity of a NOx occlusion reduction type catalyst arranged on an exhaust path of the engine. <P>SOLUTION: This air-fuel ratio control method is designed for the engine 1 having an exhaust emission control system 10 with the NOx occlusion reduction type catalyst 32 arranged on the exhaust path 2 of the engine 1. When the rich condition of the exhaust gas is temporarily generated to regenerate the NOx occlusion reduction type catalyst 32, the loaded condition of the engine 1 is judged. During at the time of a low load, the rich condition of the exhaust gas is generated by retarding air intake throttling and main injection, and at the time of intermediate and high loads, the rich condition of the exhaust gas is generated by post injection. <P>COPYRIGHT: (C)2004,JPO&NCIPI</p> |
