| 摘要 |
<p>An exhaust gas purification system for a diesel engine (2) with a lean NOx catalyst (4) includes a temperature detecting means (6), an excess air ratio changing means (8) capable of changing an excess air ratio without changing a fuel injection amount, a control means for controlling the excess air ratio changing means (8) so as to increase the excess air ratio when the exhaust gas temperature is higher than an upper limit of a predetermined temperature range and to decrease the excess air ratio when the exhaust gas temperature is lower than a lower limit of a predetermined temperature range. In the exhaust gas purification system, the exhaust gas temperature can be controlled to the temperature range independently of the fuel injection amount. <IMAGE></p> |
