EXHAUST EMISSION CONTROL DEVICE FOR ENGINE

• Main Authors: TOMITA YOSHIAKI, ISHIHARA TSUTOMU, TSUBOI GORO, YAMAGUCHI YOSHIMASA, IKEDA HIROSHI
• Format: Patent
• Language: English; Japanese
• Published: 26.04.2018
• Subjects: BLASTING; COMBUSTION ENGINES; CONTROLLING COMBUSTION ENGINES; 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; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS; 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 provide an exhaust emission control device for an engine capable of actualizing efficient NOemission control by reducing and correcting the amount of NHto be supplied to a SCR catalyst while suitably setting the reduction amount.SOLUTION: In the state that the air-fuel ratio of exhaust gas flowing into a NOcatalyst is rich and in the case that NOstored in the NOcatalyst is reduced into N, a NHsupply amount control part reduces and corrects the amount of NHto be supplied to the SCR catalyst by a NHsupply part. The amount of a reduction in the amount of the NHto be supplied by the NHsupply amount control part is set to be greater as the degree of thermal deterioration of the NOcatalyst detected or estimated by a NOcatalyst thermal deterioration grasping part is higher.SELECTED DRAWING: Figure 11 【課題】ＳＣＲ触媒へのＮＨ３の供給量を削減補正する際において、当該削減量を好適に設定することによって、効率的なＮＯＸの浄化を実現できるエンジンの排気浄化制御装置を提供すること。【解決手段】ＮＨ３供給量制御部が、ＮＯＸ触媒に流入する排気ガスの空燃比がリッチな状態であって当該ＮＯＸ触媒が吸蔵していたＮＯＸがＮ２に還元されている際には、ＮＨ３供給部によるＳＣＲ触媒へのＮＨ３の供給量を削減補正する。ＮＨ３供給量制御部によるＮＨ３の供給量の削減量は、ＮＯＸ触媒熱劣化把握部によって検出ないし推定されるＮＯＸ触媒の熱劣化の程度が大きい程、多量であるように設定されている。【選択図】図１１