EXHAUST GAS PROCESSING SYSTEM

To increase appropriately an exhaust gas temperature flowing into PM removal filter at the time of driving under highland environmental state or when oxidation catalyst is deteriorated.SOLUTION: When manual regeneration start operation is carried out (YES at S100), a control device performs a control processing that comprises a step (S108) for executing a first temperature rising control; when an exhaust gas temperature is higher than a threshold value (YES at S110), a step for calculating a fuel added amount (S112); a step (S114) for executing a fuel adding control; a step (S116) for calculating an increased temperature value; when the increased temperature value is smaller than the threshold value (YES at S118) and a varying amount of the engine speed is smaller than the threshold value (YES at S120), a step (S122) for calculating a difference between a real increased temperature value and a target increased temperature value; a step (S124) for executing a second increased temperature control; and when PM accumulated amount is smaller than the threshold value, a step (S128) for finishing a regeneration control.SELECTED DRAWING: Figure 3 【課題】高地環境下での運転時や酸化触媒の劣化時においてＰＭ除去フィルタに流入する排気温度を適切に昇温する。【解決手段】制御装置は、手動再生開始操作がある場合に（Ｓ１００にてＹＥＳ）、第１昇温制御を実行するステップ（Ｓ１０８）と、排気温度がしきい値よりも大きいと（Ｓ１１０にてＹＥＳ）、燃料添加量を算出するステップ（Ｓ１１２）と、燃料添加制御を実行するステップ（Ｓ１１４）と、昇温代を算出するステップ（Ｓ１１６）と、昇温代がしきい値よりも小さく（Ｓ１１８にてＹＥＳ）、かつ、エンジン回転数の変動量がしきい値よりも小さい場合（Ｓ１２０にてＹＥＳ）、実昇温代と目標昇温代との差分を算出するステップ（Ｓ１２２）と、第２昇温制御を実行するステップ（Ｓ１２４）と、ＰＭ堆積量がしきい値よりも小さいと再生制御を終了するステップ（Ｓ１２８）とを含む、制御処理を実行する。【選択図】図３