| abstract |
The present invention relates to an exhaust gas purification apparatus for an internal combustion engine, and effectively improves the NOx purification rate. SOLUTION: A DPF 16 that collects PM in exhaust gas, a urea water injection device 21 that injects urea water into exhaust gas, an SCR 22 that reduces and purifies NOx in exhaust gas, and a static that detects capacitance of the DPF 16 capacity detection unit 17a, and 17b, 41, a PM accumulation amount calculation unit 42 that calculates the PM accumulation amount based on the electrostatic capacitance, NO 2 consumption estimation for calculating the consumption of NO 2 on the basis of the PM accumulation amount And a control unit 44, 45 for controlling the engine 10 so that the ratio of NO to NO 2 flowing into the SCR 22 approaches 1: 1 based on the estimated consumption. [Selection] Figure 1 |