EXHAUST EMISSION CONTROL DEVICE

To provide an exhaust emission control device capable of purifying an ammonia component in exhaust gas by using a simple structure and control and suppressing outflow of the ammonia component to outside.SOLUTION: An exhaust emission control device includes: a tank that stores liquid in which an ammonia component can be dissolved; an exhaust gas treatment passage for causing exhaust gas discharged from a three-way catalyst to pass through the liquid and releasing the exhaust gas to outside; and an exhaust gas supply pump for supplying exhaust gas from an exhaust passage to the exhaust gas treatment passage. When an internal combustion engine is being operated in a first state where a temperature of the three-way catalyst is a predetermined temperature or higher and an air-fuel ratio of exhaust gas flowing into the three-way catalyst is on a rich side of a theoretical air fuel ratio and an ammonia component is generated in the three-way catalyst (Yes in Step S2), a control section operates the exhaust gas supply pump to send the exhaust gas to the tank and dissolves the ammonia component included in the exhaust gas in the liquid for recovery (Step S3).SELECTED DRAWING: Figure 2 【課題】簡素な構造と制御により排気ガス中のアンモニア成分を浄化でき、アンモニア成分の外部への流出を抑制できる排気ガス浄化装置を提供すること。【解決手段】排気ガス浄化装置は、アンモニア成分を溶解できる液体を貯留したタンクと、三元触媒から排出される排気ガスを液体に通過させて外部に放出する排気ガス処理通路と、排気通路から排気ガス処理通路に排気ガスを供給する排気ガス供給ポンプと、を備えている。制御部は、三元触媒の温度が所定温度以上であり、かつ、三元触媒に流入する排気ガスの空燃比が理論空燃比よりもリッチ側である第１状態で内燃機関が運転されており、三元触媒でアンモニア成分が生成される場合（ステップＳ２でＹＥＳ）、排気ガス供給ポンプを作動させて排気ガスをタンクに送り、排気ガス中に含まれるアンモニア成分を液体に溶解させて回収する（ステップＳ３）。【選択図】図２