| abstract |
Even if a configuration in which an oxidation catalyst is disposed in front of a selective catalytic reduction catalyst is used, generation of excessive NO 2 by the oxidation catalyst is suppressed and a drop in the NOx reduction rate is avoided. An exhaust gas purification apparatus in which an oxidation catalyst 11 is disposed in front of a selective catalytic reduction catalyst 13 is provided with a bypass flow path 14 that bypasses the exhaust gas 7 with respect to the catalytic oxidation catalyst 11 and leads the selective catalytic reduction catalyst 13 to the oxidation. When the catalyst 11 is in an operation state in which NO 2 is excessively generated, a part of the exhaust gas 7 is led to the selective reduction catalyst 13 by bypassing the oxidation catalyst 11 via the bypass flow path 14. The amount of NO 2 produced is appropriately suppressed. [Selection] Figure 1 |