| 摘要 |
PROBLEM TO BE SOLVED: To provide an exhaust emission control device for an internal combustion engine, securing an exhaust gas flow rate necessary for cooling a filter and surely preventing excessive temperature rise of the filter, even in an operational status where the exhaust gas flow rate is suddenly decreased.SOLUTION: The exhaust emission control device for the internal combustion engine controls the exhaust gas flow rate to be on an increase side to prevent the excessive temperature rise of the filter 8 collecting particulate in the exhaust gas when an exhaust gas flow rate QEX is smaller than a lower limit value QLMTL (S19-S21 in Fig.3). Further, the exhaust emission control device controls to set a lower limit value QLMTL to be a first lower limit value QLMTL1 smaller than the lower limit value QLMTL when an exhaust gas decrease amount ΔQEXDEC is a predetermined threshold value ΔQREF or smaller, and controls to set the lower limit value QLMTL to be a second lower limit value QLMTL2 larger than the lower limit value QLMTL when the exhaust gas decrease amount ΔQEXDEC is larger than the threshold ΔQREF (S14-S18 in Fig.3). |
