EXHAUST EMISSION CONTROL DEVICE

PROBLEM TO BE SOLVED: To solve a problem that non-inflammable constituents captured by a filter together with PMs in exhaust gas discharged from an internal combustion engine are not removed from the filter only by burning the inflammable PMs.SOLUTION: An exhaust emission control device 27 includes: a catalyzing DPF 31 for capturing PMs and non-inflammable constituents included in exhaust gas flowing in an exhaust passage 23a of an engine 10; means 16a, 33 for acquiring accumulation amounts of the PMs and the non-inflammable constituents captured by the DPF, respectively; combustion means 26, 30 for burning the captured PMs; and control means 16h, 16i for controlling an operation of the combustion means. When the accumulation amount of the PMs is a predetermined value or more and the accumulation amount of the non-inflammable constituents is less than a second predetermined value, the control means controls the operation of the combustion means so that a temperature of the DPF is raised to a first temperature T. When the accumulation amount of the PMs is the predetermined value or more and the accumulation amount of the non-inflammable constituents is the second predetermined value or more, the control means controls the operation of the combustion means so that the temperature of the DPF is raised to a second temperature Tlower than the first temperature.SELECTED DRAWING: Figure 1 【課題】内燃機関から排出される排気中のＰＭと共にフィルターに捕捉される不燃成分は、可燃性のＰＭを燃焼させただけではフィルターから除去されない。【解決手段】本発明による排気浄化装置２７は、エンジン１０の排気通路２３ａを流れる排気に含まれるＰＭおよび不燃成分を捕捉する触媒化ＤＰＦ３１と、このＤＰＦに捕捉されたＰＭおよび不燃成分の堆積量をそれぞれ取得する手段１６ａ，３３と、捕捉されたＰＭを燃焼させる燃焼手段２６，３０と、燃焼手段の作動を制御する制御手段１６ｈ，１６ｉとを具える。制御手段は、ＰＭの堆積量が所定値以上、かつ不燃成分の堆積量が第２の所定値未満の場合、ＤＰＦの温度が第１の温度ＴHへと上昇するように燃焼手段の作動を制御し、ＰＭの堆積量が所定値以上、かつ不燃成分の堆積量が第２の所定値以上の場合、ＤＰＦの温度が第１の温度よりも低い第２の温度ＴLへと上昇するように、燃焼手段の作動を制御する。【選択図】図１