| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method and a device for controlling operation of an internal combustion engine using both an SCR system and an EGR system in which overheat of the internal combustion engine can be prevented while keeping an NO<SB POS="POST">X</SB>amount in exhaust gas at or below a reference value. <P>SOLUTION: In the device, there included are cooling water circulation paths 42a, 42b circulating cooling water between a radiator 40 and an engine block 12, and a branch cooling water circulation path 48 branched off from the cooling water circulation path 42b and connected to an EGR cooler 46 provided in an EGR path 44. When temperature t of the cooling water is not more than a threshold value T0, the operation is transitioned to a normal operation control mode by a controller 60. When the temperature t of the cooling water exceeds the threshold value T0 and an SCR catalyst 36 is at an active temperature, an EGR amount is reduced and the operation is transitioned to a first operation control mode to increase an additive amount of urea water. When the temperature t of the cooling water exceeds the threshold value T0 and the SCR catalyst 36 is not at the active temperature, the operation is transitioned to a second operation control mode to reduce engine power. <P>COPYRIGHT: (C)2013,JPO&INPIT |
