JP2018178981A5

JP2018178981A5 -

Info

Publication number: JP2018178981A5
Application number: JP2017084886A
Authority: JP
Filing date: 2017-04-21
Publication date: 2019-07-25
Anticipated expiration: 2037-04-21

Description

本発明は、排気に含まれる成分を酸化又は還元する三元触媒（２６）と、前記排気に含まれる粒子状物質を捕集する粒子フィルタ（２７）とが排気通路（２２）に設けられた内燃機関（１０）に適用され、所定の実施条件が成立した場合に、前記粒子フィルタに捕集された前記粒子状物質を燃焼除去する排気処理装置に関する。第１の構成は、前記粒子フィルタに捕集された前記粒子状物質の燃焼除去の実施期間において、前記内燃機関から排出される窒素酸化物の量が所定の排出許容値以下になるように前記内燃機関の空燃比を制御する空燃比制御部を備えることを特徴とする。 In the present invention, the exhaust passage (22) is provided with a three-way catalyst (26) for oxidizing or reducing components contained in exhaust gas, and a particle filter (27) for collecting particulate matter contained in the exhaust gas. The present invention relates to an exhaust treatment device which is applied to an internal combustion engine (10) and which burns and removes the particulate matter collected by the particle filter when predetermined operation conditions are satisfied. According to a first configuration , the amount of nitrogen oxides discharged from the internal combustion engine becomes equal to or less than a predetermined discharge allowable value in a period during which the particulate matter collected by the particle filter is burnt and removed. The air-fuel ratio control unit controls the air-fuel ratio of the internal combustion engine.

Claims

Internal combustion engine (10) provided in an exhaust passage (22) with a three-way catalyst (26) for oxidizing or reducing a component contained in exhaust gas, and a particle filter (27) for collecting particulate matter contained in the exhaust gas. Applies to) and
An exhaust treatment device which burns and removes the particulate matter collected by the particle filter when a predetermined operation condition is satisfied.
The air-fuel ratio of the internal combustion engine is theoretically set so that the amount of nitrogen oxides discharged from the internal combustion engine during the burnout of the particulate matter collected by the particle filter becomes equal to or less than a predetermined discharge allowable value. An exhaust processing device for an internal combustion engine, comprising an air-fuel ratio control unit that performs control on the lean side of the air-fuel ratio.

The air-fuel ratio control unit controls the concentration of oxygen in the exhaust gas supplied to the particulate filter, and the amount of nitrogen oxides discharged from the internal combustion engine becomes less than the predetermined discharge allowable value during the period of the combustion removal. The exhaust gas processing device for an internal combustion engine according to claim 1, wherein the air-fuel ratio is controlled to be equal to or higher than a predetermined concentration determined based on the demand for the burning rate of the particulate matter.

A first air-fuel ratio calculation unit that calculates a first required air-fuel ratio, which is an air-fuel ratio for making the oxygen concentration in the exhaust supplied to the particle filter the oxygen concentration that satisfies the requirement of the burning rate of the particulate matter When,
A second air-fuel ratio calculation unit that calculates a second required air-fuel ratio, which is an air-fuel ratio for making the amount of nitrogen oxides discharged from the internal combustion engine less than the predetermined discharge allowable value during the period of implementation of the combustion removal; , And
The air-fuel ratio control unit controls the air-fuel ratio of the internal combustion engine such that the air-fuel ratio of the first required air-fuel ratio and the second required air-fuel ratio becomes the air-fuel ratio with the larger deviation amount from the stoichiometric air-fuel ratio. An exhaust treatment device for an internal combustion engine according to claim 1 or 2.

The exhaust gas processing apparatus for an internal combustion engine according to claim 3, wherein the second air fuel ratio calculation unit calculates the second required air fuel ratio based on a load of the internal combustion engine.

It has a temperature rise control unit which performs post injection for supplying fuel to the internal combustion engine after main injection of the internal combustion engine to raise the temperature of the particle filter.
The air-fuel ratio control unit is configured such that the amount of nitrogen oxides discharged from the internal combustion engine during the period of the combustion removal becomes equal to or less than the predetermined discharge allowable value, and after combustion of fuel injected by the post injection. oxygen concentration in the exhaust gas supplied to the particle filter, for controlling the air-fuel ratio to be equal to or greater than the predetermined concentration determined based on the requirements of burning rate of the particulate matter, any of claims 2-4 one An exhaust treatment device for an internal combustion engine according to the item

The exhaust gas treatment of an internal combustion engine according to claim 1 or 2, wherein the air-fuel ratio control unit controls an air-fuel ratio of the internal combustion engine at a misfire limit air-fuel ratio which is a limit of an air-fuel ratio capable of normal combustion in the internal combustion engine. apparatus.