| 摘要 |
In order to appropriately control the state of corona discharge according to the exhaust air-fuel ratio and purify PM in exhaust gas always efficiently, an engine (10) is provided with a corona discharge-type exhaust purification device (24). The exhaust purification device (24) purifies particulate matter (PM) in exhaust gas by generating corona discharge between a center electrode (62) and a ground electrode (64). An ECU (50) controls the applied voltage to be applied between the electrodes (62, 64) when the air-fuel ratio is in a rich region. Consequently, the maximum PM purification rate can be obtained while arc discharge is prevented. When the air-fuel ratio is in a lean region, the discharge current flowing between the electrodes (62, 64) is controlled. Consequently, power consumption can be suppressed while the reduction of the PM purification rate due to the reduction of the amount of PM in the exhaust gas is compensated for. |
