| 摘要 |
An object of this invention is to appropriately control the state of a corona discharge in accordance with an exhaust air-fuel ratio, and always purify PM in exhaust gas efficiently. An engine 10 is equipped with a corona discharge-type exhaust emission control device 24. The exhaust emission control device 24 purifies particulate matter (PM) in exhaust gas by generating a corona discharge between a center electrode 62 and an earth electrode 64. When the air-fuel ratio is in a rich region, an ECU 50 controls an applied voltage that is applied between the electrodes 62 and 64. It is thereby possible to obtain a maximum PM purification rate while preventing an arc discharge. When the air-fuel ratio is in a lean region, a discharge current flowing between the electrodes 62 and 64 is controlled. It is thereby possible to suppress power consumption while compensating for a decrease in the PM purification rate caused by a reduction in the PM amount in the exhaust gas. |
