摘要 |
An ECU performs PM removal control, in which the bed temperature of a DPF is adjusted to a target bed temperature through addition of unburned fuel to exhaust gas. In the PM removal control, the ECU learns a learned value of a fuel addition amount by which the difference between the bed temperature and the target bed temperature of the DPF is corrected. When the determination in step S510 is positive, in other words, when it is determined that the flow of the exhaust gas to the DPF is in a steady state, the ECU stores a correction value K as a steady state learned value Ka in step S520. When the determination in step S510 is negative, in other words, when it is determined that the flow of the exhaust gas is in a transient state, the ECU stores the correction value K as a transient state learned value Kb in step S530. In the PM removal control, the ECU reflects the transient state learned value Kb in the fuel addition amount. NOx reduction control is carried out based only on the steady state learned value Ka. |