| 摘要 |
PROBLEM TO BE SOLVED: To prevent accumulation of deposit in an EGR passage 81 even when performing control for recovering a function of an exhaust emission control device such as a De-NOx catalyst 74 (for example, NOx reduction control) in a diesel engine 1.SOLUTION: During NOx reduction control, after main injection of fuel is performed by an injector 2, post injection of fuel is performed in an expansion stroke of a cylinder 10 to make an air-fuel ratio of exhaust gas rich, and EGR gas is made to flow in an EGR passage 81 to recirculate in an intake passage 6. At this time, the post injection is performed while a cylinder temperature TA is higher than a preset temperature TA1 so that a rate of an SOF in PMs in the exhaust gas (SOF/PM) is a predetermined rate or lower.SELECTED DRAWING: Figure 3 |
