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; STEAM ENGINES; 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 NHsupply means. The amount of a reduction in the amount of the NHto be supplied by the NHsupply amount control part is set to be smaller as the temperature of the NOcatalyst detected or estimated by a NOcatalyst temperature grasping part is higher.SELECTED DRAWING: Figure 8 【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供給手段による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触媒温度把握部によって検出ないし推定されるＮＯＸ触媒の温度が高温である程、少量であるように設定されている。【選択図】図８