EXHAUST EMISSION CONTROL DEVICE FOR ENGINE

• Main Authors: ANODA HIROSHI, TASHIRO KEISUKE
• Format: Patent
• Language: English; Japanese
• Published: 06.10.2016
• Subjects: BLASTING; ENGINE PLANTS IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNALCOMBUSTION ENGINES; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES ORENGINES IN GENERAL; HEATING; LIGHTING; MACHINES OR ENGINES IN GENERAL; MECHANICAL ENGINEERING; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; SEPARATION; STEAM ENGINES; TRANSPORTING; WEAPONS

PROBLEM TO BE SOLVED: To improve exhaust emission control performance.SOLUTION: An exhaust emission control device in an exhaust passage 10 of an engine 2, includes: a filter 12 for collecting PMs in exhaust gas; a selective reduction catalyst 13 provided downstream of the filter 12 for reducing and eliminating NOx by using ammonia generated by hydrolyzing urea water; and an NOx occlusion catalyst 11 provided upstream of the filter 12. An engine control unit 30 performs filter regeneration control for burning and removing the PMs stored in the filter 12 and purge control for removing a sulfur constituent in exhaust gas adsorbed in the NOx occlusion catalyst 11 by increasing exhaust temperature in accordance with request determination. When the request determination of the filter regeneration control or the purge control is made, the engine control unit performs reducing agent supply control for supplying ammonia to the selective reduction catalyst 13 by increasing a temperature of the selective reduction catalyst 13 to an activation temperature or higher and injecting an urea water solution before the filter regeneration control or the purge control is started.SELECTED DRAWING: Figure 1 【課題】排気浄化性能を向上させる。【解決手段】エンジン２の排気通路１０に、排気中のＰＭを捕集するフィルタ１２と、フィルタ１２の下流側に設けられ、尿素水を加水分解して発生させるアンモニアを用いてＮＯxを還元除去する選択還元触媒１３と、フィルタ１２の上流側に設けられたＮＯx吸蔵触媒１１と、を備えた排気浄化装置であって、エンジンコントロールユニット３０は、排気温度を上昇させ、フィルタ１２に貯留されたＰＭを燃焼除去するフィルタ再生制御と、ＮＯx吸蔵触媒１１に吸着された排気中の硫黄成分を除去するパージ制御とを要求判定に応じて行なうとともに、フィルタ再生制御またはパージ制御が要求判定された際に、当該フィルタ再生制御またはパージ制御の開始前に、選択還元触媒１３の温度を活性温度以上に上昇させるともに尿素水溶液を噴射してアンモニアを選択還元触媒１３に供給する還元剤供給制御を行う。【選択図】図１