| 摘要 |
<p>When the engine is operated under a light-load condition, a gas mixture is stratified with a high average air-fuel ratio in the combustion chamber (5). NOx produced in this case is absorbed in an NOx absorbent (26) provided in the exhaust passage. The average air-fuel ratio in the combustion chamber (5) is lowered so as to release NOx from the NOx absorbent (26) in such a way that the air-fuel ratio of the mixture around the ignition plug (10) does not vary greatly. This enables the average air-fuel ration A/F to be switched from a high level to a low level and enable the NOx to be released from the NOx absorbent without causing the gas mixture around the ignition plug to become excessively rich, preventing misfire and change in the output torque of the engine.</p> |
