| 摘要 |
The present invention relates to an exhaust gas purification device of an internal combustion engine, and effectively increases a NOx purification rate. The exhaust gas purification device includes a DPF (16) that collects PM from an exhaust gas, a urea water spray unit (21) that sprays urea water into the exhaust gas, an SCR (22) that reduces and purifies NOx of the exhaust gas, a capacitance detecting unit (17a, 17b, 41) that detects capacitance of the DPF (16), a PM accumulation calculating unit (42) that calculates an amount of accumulated PM on the basis of the capacitance, an NO 2 consumption estimating unit (43) that calculates an amount of consumed NO 2 on the basis of the amount of accumulated PM, and a control unit (44, 45) that controls an engine (10) such that a ratio of NO to NO 2 flowing into the SCR (22) approaches 1:1 on the basis of the estimated consumption. |
