| 摘要 |
PROBLEM TO BE SOLVED: To properly control EGR gas supply operation irrespective of execution or stop of cooling water circulation inside a block-side cooling water passage. SOLUTION: A head-side cooling water passage 21 is formed inside a cylinder head 3, while a block-side cooling water passage 20 is formed inside a cylinder block 1. Cooling water circulation operation in the block-side cooling water passage 20 can be stopped without stopping cooling water circulation operation in the head-side cooling water passage 21. When the cooling water temperature is higher than a preset value, an EGR control valve 18 is opened to execute EGR gas supply. When the cooling water temperature is lower than the preset value, the EGR control valve 18 is closed to stop EGR gas supply. The set temperature during stoppage of the cooling water circulation in the passage 20 is lower than that when the circulation is executed in the passage 20. |
