EXHAUST EMISSION CONTROL DEVICE

PROBLEM TO BE SOLVED: To enable appropriate control of the temperature of gas to be supplied to the exhaust downstream via an oxidation catalyst.SOLUTION: An exhaust emission control device includes a basic injection amount determination part 44 for determining a basic injection amount on the basis of an inlet temperature of a DOC 21, an exhaust gas flow amount, and a target temperature for an outlet temperature, a first estimation part 46 for estimating a temperature change in the outlet temperature on the basis of a response model, an inlet temperature processing part 42 for outputting the inlet temperature to the basic injection amount determination part 44 while making up for a delay time for the response of the response model from a change in the supply amount to a change in the outlet temperature, a second estimation part 47 for estimating the outlet temperature on the basis of the response model for the outlet temperature to the change in the inlet temperature, a feedback operation part 49 for finding a corrected injection amount to eliminate a deviation between the estimated outlet temperature based on the temperature change in the estimated outlet temperature and the outlet temperature, and the outlet temperature, and a regeneration control part 41 for controlling a controlled injection amount obtained by adding the basic injection amount and the corrected injection amount to be output to an in-exhaust-pipe injection device 23.SELECTED DRAWING: Figure 2 【課題】酸化触媒を介して排気下流に供給されるガスの温度を適切に制御できるようにする。【解決手段】ＤＯＣ２１の入口温度、排気ガス流量、出口温度の目標温度に基づいて、基本噴射量を決定する基本噴射量決定部４４と、応答モデルに基づいて出口温度の温度変化を推定する第１推定部４６と、入口温度に対して、応答モデルにおける供給量変化から出口温度が変化するまでの応答の遅れ分を進ませるようにして基本噴射量決定部４４に出力する入口温度処理部４２と、入口温度の変化に対する出口温度の応答モデルに基づいて、出口温度を推定する第２推定部４７と、推定された出口温度の温度変化と出口温度とに基づく出口推定温度と、出口温度との偏差を解消するために、補正噴射量を求めるフィード・バック演算部４９と、基本噴射量と補正噴射量とを加算した制御噴射量を排気管内噴射装置２３に出力させるよう制御する再生制御部４１と、を有するようにする。【選択図】図２