| 摘要 |
PROBLEM TO BE SOLVED: To provide an exhaust emission control device for an internal combustion engine, in which reaction in an exhaust system is surely performed and exhaust emission control efficiency is implemented without cost-up unlike the conventional secondary air technique, even when increasing exhaust pressure. SOLUTION: The exhaust emission control device comprises: communication passages 15, 16 that connect an exhaust passage 20a with an exhaust passage 26b and are independently disposed for each of a cylinder group #1, #4 and a cylinder group #2, #3; an exhaust flow control means 40 for restricting an exhaust flow in the two exhaust passages; and a discharge oxygen amount increasing means for increasing an oxygen amount in exhaust emitted from one cylinder group #1, #4 out of the two cylinder groups when temperature rise of the exhaust is required. The exhaust flow control means 40 controls the exhaust flow so that the restriction of the exhaust flow from one exhaust group #1, #4 becomes larger than the restriction of the exhaust flow from the other exhaust group #2, #3, when the discharge oxygen amount increasing means increases the oxygen amount in the exhaust emitted from one cylinder group ##1, #4.
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