JP2002349252A - Exhaust gas control system - Google Patents
Exhaust gas control systemInfo
- Publication number
- JP2002349252A JP2002349252A JP2001153716A JP2001153716A JP2002349252A JP 2002349252 A JP2002349252 A JP 2002349252A JP 2001153716 A JP2001153716 A JP 2001153716A JP 2001153716 A JP2001153716 A JP 2001153716A JP 2002349252 A JP2002349252 A JP 2002349252A
- Authority
- JP
- Japan
- Prior art keywords
- nox
- purification catalyst
- exhaust gas
- catalyst
- nox purification
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、ＥＧＲシステムを
備えたエンジンにおいて、排気ガス中のＮＯｘを吸収及
び分解するＮＯｘ浄化触媒で、排気ガス中のＮＯｘを浄
化する排気ガス浄化システムに関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying system for purifying NOx in exhaust gas with an NOx purifying catalyst for absorbing and decomposing NOx in exhaust gas in an engine having an EGR system. .
【０００２】[0002]
【従来の技術】ディーゼル機関や一部のガソリン機関等
のエンジンや様々な燃焼装置の排ガス中から窒素酸化物
（ＮＯｘ）を還元除去するためのＮＯｘ触媒について種
々の研究や提案がなされている。2. Description of the Related Art Various studies and proposals have been made on NOx catalysts for reducing and removing nitrogen oxides (NOx) from exhaust gas from engines such as diesel engines and some gasoline engines and various combustion devices.
【０００３】これらのＮＯｘ触媒の中に、三元触媒と異
なり排ガス中に酸素が存在していてもＮＯｘの浄化を行
うことができ、希薄燃焼（リーン燃焼）ガソリンエンジ
ンやディーゼルエンジンの排ガスの浄化に使用あるいは
使用の検討がなされている、ＮＯｘを吸収及び分解する
ＮＯｘ浄化触媒がある。[0003] Unlike these three-way catalysts, these NOx catalysts can purify NOx even if oxygen is present in the exhaust gas, thereby purifying exhaust gas from lean-burn (lean-burn) gasoline engines and diesel engines. There is a NOx purification catalyst which absorbs and decomposes NOx, which is being used or studied for its use.
【０００４】このＮＯｘを吸収及び分解できるＮＯｘ浄
化触媒としては、ブラウンミラライト型触媒やその他の
ＮＯｘ吸蔵還元型触媒等が知られているが、このＮＯｘ
浄化触媒では、通常の状態では、排気ガス中のＮＯｘを
ＮＯｘ吸収物質で吸収することにより、排ガス中のＮＯ
ｘを除去して、排ガスを浄化して排出している。As a NOx purifying catalyst capable of absorbing and decomposing NOx, a brown-millerite type catalyst and other NOx storage reduction type catalysts are known.
In a purification catalyst, in a normal state, NOx in exhaust gas is absorbed by a NOx absorbing substance to thereby reduce NOx in exhaust gas.
x is removed, and the exhaust gas is purified and discharged.
【０００５】しかし、このＮＯｘ吸収状態が継続する
と、ＮＯｘ浄化触媒が飽和して、ＮＯｘの吸収能力が低
下するので、ＮＯｘ浄化触媒から、吸収していたＮＯｘ
を短時間の間で分解させて、ＮＯｘ浄化触媒の吸収能力
を回復させる再生処理を行う必要がある。[0005] However, if the NOx absorption state continues, the NOx purification catalyst saturates and the NOx absorption capacity decreases, so that the NOx absorbed from the NOx purification catalyst is reduced.
Needs to be decomposed in a short time to perform a regeneration process for restoring the absorption capacity of the NOx purification catalyst.
【０００６】このＮＯｘ浄化触媒に吸収されたＮＯｘを
分解する場合には、このＮＯｘ浄化触媒から放出される
ＮＯｘを、還元雰囲気、雰囲気中に含まれるＣＯ，Ｈ
Ｃ，Ｈ 2 等の還元剤、触媒近傍に添加した還元触媒等に
より、窒素ガスＮ2 に還元して浄化し、外部へのＮＯｘ
の排出を回避している。[0006] The NOx absorbed by the NOx purification catalyst is
When decomposed, it is released from this NOx purification catalyst
NOx is reduced to CO, H contained in reducing atmosphere and atmosphere.
C, H TwoEtc., reducing catalysts added near the catalyst, etc.
From nitrogen gas NTwoNOx to the outside
Avoids emissions.
【０００７】[0007]
【発明が解決しようとする課題】しかしながら、吸収さ
れたＮＯｘを積極的に放出させる再生処理をする場合に
は、短時間の間ではあるが、ＮＯｘ量が多くなるため、
ＮＯｘ浄化触媒から放出されるＮＯｘを全て完全に分解
することは難しく、放出されたＮＯｘの分解処理が不十
分となるという問題がある。However, when a regeneration process for positively releasing the absorbed NOx is performed, the amount of NOx increases for a short period of time.
It is difficult to completely decompose all the NOx released from the NOx purification catalyst, and there is a problem that the decomposition process of the released NOx becomes insufficient.
【０００８】一方、ＮＯｘ濃度が比較的高い排気ガスを
エンジンの燃焼室に還流させても、この排気ガス中のＮ
Ｏｘが燃焼室で還元されるため、外部に排出される排気
ガス中のＮＯｘ濃度が高くならず、浄化効率を良好に維
持できることが分かった。On the other hand, even if the exhaust gas having a relatively high NOx concentration is recirculated to the combustion chamber of the engine, the N
It has been found that since Ox is reduced in the combustion chamber, the NOx concentration in the exhaust gas discharged to the outside does not increase, and the purification efficiency can be maintained satisfactorily.
【０００９】本発明は、この知見を得て、上述の問題を
解決するためになされたものであり、その目的は、ＮＯ
ｘを吸収及び分解するＮＯｘ浄化触媒を備えた排気ガス
浄化システムにおいて、ＥＧＲ制御とＮＯｘ浄化触媒か
らのＮＯｘの分解及び放出とを連携させることにより、
外部に排出されるＮＯｘ量を低減できる排気ガス浄化シ
ステムを提供することにある。The present invention has been made to solve the above-mentioned problems based on this finding.
In an exhaust gas purification system including a NOx purification catalyst that absorbs and decomposes x, by linking EGR control and decomposition and release of NOx from the NOx purification catalyst,
An object of the present invention is to provide an exhaust gas purification system capable of reducing the amount of NOx discharged to the outside.
【００１０】[0010]
【課題を解決するための手段】以上のような目的を達成
するための排気ガス浄化システムは、次のように構成さ
れる。The exhaust gas purifying system for achieving the above object is constituted as follows.
【００１１】１）ＥＧＲバルブを有するＥＧＲガス還流
通路を備えたエンジンにおいて、排気ガス中のＮＯｘを
吸収及び分解するＮＯｘ浄化触媒と、該ＮＯｘ浄化触媒
に吸収されたＮＯｘを分解し、該ＮＯｘ浄化触媒を再生
するための再生手段とを有して形成されるＮＯｘ浄化装
置を、前記ＥＧＲガス還流通路が分岐する位置よりも上
流側の排気通路に設けて構成される。1) In an engine having an EGR gas recirculation passage having an EGR valve, a NOx purifying catalyst for absorbing and decomposing NOx in exhaust gas, and decomposing NOx absorbed by the NOx purifying catalyst to purify the NOx A NOx purifying device formed having a regeneration unit for regenerating the catalyst is provided in an exhaust passage upstream of a position where the EGR gas recirculation passage branches.
【００１２】つまり、ＮＯｘ浄化触媒に吸収されたＮＯ
ｘを分解および放出させて、ＮＯｘ浄化触媒を再生する
機構と、放出されしかも分解できなかったＮＯｘをＥＧ
Ｒガスとしてエンジンに還流する機構を設けて構成す
る。That is, the NO absorbed by the NOx purification catalyst
a mechanism for regenerating the NOx purification catalyst by decomposing and releasing x, and a method for regenerating NOx released but not decomposed by EG
A mechanism for recirculating the R gas to the engine is provided.
【００１３】そして、ＮＯｘ浄化触媒に吸収されたＮＯ
ｘを放出させながら、ＮＯｘを効率よく還元及び分解し
てＮＯｘ浄化触媒を再生し、ＮＯｘ浄化触媒の浄化能力
の維持と耐久性向上を図ると共に、ＮＯｘ浄化触媒から
放出され、分解されずにＮＯｘ浄化触媒を通過したＮＯ
ｘをＥＧＲガス還流通路経由でエンジンに戻し、再度燃
焼することでＮＯｘを還元し、ＮＯｘ浄化率の低下を防
止する。Then, the NO absorbed by the NOx purification catalyst
While releasing x, NOx is efficiently reduced and decomposed to regenerate the NOx purification catalyst to maintain the purification ability of the NOx purification catalyst and improve durability, and to release NOx from the NOx purification catalyst without being decomposed. NO that has passed through the purification catalyst
x is returned to the engine via the EGR gas recirculation passage, and is burned again to reduce NOx, thereby preventing a decrease in the NOx purification rate.
【００１４】２）また、上記の排気ガス浄化システムに
おいて、前記ＮＯｘ浄化触媒に、該ＮＯｘ浄化触媒のＮ
Ｏｘ浄化触媒の導電率を計測する導電率計測部を設ける
と共に、該導電率計測部で計測されたＮＯｘ浄化触媒の
導電率に基づいて、前記ＥＧＲバルブの弁開度の制御を
行う制御手段を備えて構成される。2) In the exhaust gas purifying system described above, the NOx purifying catalyst is provided with the Nx of the NOx purifying catalyst.
A control unit for providing a conductivity measuring unit for measuring the conductivity of the Ox purification catalyst and controlling the valve opening of the EGR valve based on the conductivity of the NOx purification catalyst measured by the conductivity measuring unit is provided. It is configured with.
【００１５】また、エンジン回転数、負荷に応じて制御
するＥＧＲに加えて、ＮＯｘ吸収量に応じて変化するＮ
Ｏｘ浄化触媒の導電率に基づいて、ＥＧＲバルブの制御
を行うことにより、より極め細かくＮＯｘ浄化触媒のＮ
Ｏｘ除去効率の制御が可能となり、外部に排出されるＮ
Ｏｘ量を低減することができる。Further, in addition to the EGR controlled according to the engine speed and the load, N which varies according to the NOx absorption amount is changed.
By controlling the EGR valve based on the conductivity of the Ox purification catalyst, the Nx of the NOx purification catalyst can be more finely controlled.
Ox removal efficiency can be controlled, and N discharged to the outside
Ox amount can be reduced.
【００１６】３）更に、上記の排気ガス浄化システムに
おいて、前記ＮＯｘ浄化触媒が、希土類元素、アルカリ
土類金属元素、アルカリ金属元素の内、少なくとも１種
類以上の元素を含有するブラウンミラライト型複合酸化
物と、ブラウンミラライト粒子表面に分散した貴金属と
から形成される。3) Further, in the above exhaust gas purification system, the NOx purification catalyst is a brown-millerite-type composite containing at least one or more of a rare earth element, an alkaline earth metal element and an alkali metal element. It is formed from an oxide and a noble metal dispersed on the surface of brown milalite particles.
【００１７】この構成により、ブラウンミラライト型複
合酸化物により効率よくＮＯｘを吸収し、貴金属によ
り、加熱等の再生処理によって、ブラウンミラライト型
複合酸化物にから放出されるＮＯｘを還元することがで
きるので、排気ガス中のＮＯｘを連続して浄化できる。With this structure, NOx can be efficiently absorbed by the brown-millarite-type composite oxide, and NOx released from the brown-mirrorite-type composite oxide can be reduced by the noble metal by a regeneration treatment such as heating. Therefore, NOx in the exhaust gas can be continuously purified.
【００１８】４）そして、上記の排気ガス浄化システム
において、前記制御手段は、前記再生装置が前記ＮＯｘ
浄化触媒を再生する際に、前記ＥＧＲバルブの弁開度を
修正するように構成される。4) In the exhaust gas purifying system described above, the control means includes a step of:
When the purification catalyst is regenerated, the opening degree of the EGR valve is corrected.
【００１９】このＥＧＲバルブの弁開度の修正により、
通常のＥＧＲよりも多量のＥＧＲガスを燃焼室に還流で
きるので、ＮＯｘ浄化触媒の再生の際に、発生するＮＯ
ｘの多くを燃焼室に再循環し、ＮＯｘを分解できる。By correcting the opening degree of the EGR valve,
Since a larger amount of EGR gas can be recirculated to the combustion chamber than normal EGR, NO generated during regeneration of the NOx purification catalyst can be reduced.
Most of x can be recycled to the combustion chamber to decompose NOx.
【００２０】５）また。上記の排気ガス浄化システムに
おいて、前記再生手段を、前記ＮＯｘ浄化触媒を加熱す
る加熱装置で形成すると共に、該加熱装置を、直接加熱
する電気ヒータ、マイクロ波又は低温プラズマによる誘
導加熱を行う加熱装置のいずれか一つ又は組合せで形成
する。この構成により、再生手段を比較的簡単に形成で
きる。5) Also, In the above exhaust gas purification system, the regeneration unit is formed by a heating device that heats the NOx purification catalyst, and the heating device directly heats the heating device, and a heating device that performs induction heating by microwave or low-temperature plasma. Is formed by any one or combination. With this configuration, the reproducing means can be formed relatively easily.
【００２１】[0021]
【発明の実施の形態】以下、本発明に係る排気ガス浄化
システムについて、図面を参照しながら説明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An exhaust gas purifying system according to the present invention will be described below with reference to the drawings.
【００２２】図１に示す排気ガス浄化システム１のＮＯ
ｘ浄化装置１０は、排気ガスＧ中のＮＯｘ（窒素酸化
物）を吸収及び分解するＮＯｘ浄化触媒１１と、このＮ
Ｏｘ浄化触媒１１に吸収されたＮＯｘを分解させ再生さ
せるために、このＮＯｘ浄化触媒１１を加熱する加熱装
置（再生手段）１２とを備えて形成されるそして、この
ＮＯｘ浄化装置１０は、ＥＧＲバルブ２１を備えたＥＧ
Ｒガス還流通路２０を有するエンジン１の排気通路３に
配設されるが、排気通路３からＥＧＲガス還流通路２０
が分岐する位置２０ｂよりも、上流側に配設される。つ
まり、ＥＧＲガス還流通路２０をＮＯｘ浄化装置１０よ
りも下流側で排気通路３から分岐して、エンジン１の吸
気通路２に接続して形成する。NO of the exhaust gas purification system 1 shown in FIG.
The x purification device 10 includes a NOx purification catalyst 11 that absorbs and decomposes NOx (nitrogen oxide) in the exhaust gas G,
In order to decompose and regenerate the NOx absorbed by the Ox purification catalyst 11, the heating device (regeneration means) 12 for heating the NOx purification catalyst 11 is formed. EG with 21
The EGR gas recirculation passage 20 is disposed in the exhaust passage 3 of the engine 1 having the R gas recirculation passage 20.
Is disposed on the upstream side of the position 20b at which the branching is performed. That is, the EGR gas recirculation passage 20 branches off from the exhaust passage 3 downstream of the NOx purification device 10 and is formed to be connected to the intake passage 2 of the engine 1.
【００２３】また、ＮＯｘ浄化触媒１１は、コージェラ
イトハニカムの表面に、希土類元素、アルカリ土類金属
元素、アルカリ金属元素の内、少なくとも１種類以上の
元素を含有するブラウンミラライト型複合酸化物１１ａ
とブラウンミラライト粒子表面に分散配置した白金等の
貴金属１１ｂとを担持したＮＯｘ触媒多孔材を作製し、
このＮＯｘ触媒多孔材を金属容器内に固定して形成す
る。The NOx purification catalyst 11 has a brown-millerite-type composite oxide 11a containing at least one element selected from the group consisting of a rare earth element, an alkaline earth metal element and an alkali metal element on the surface of a cordierite honeycomb.
And producing a NOx catalyst porous material carrying a noble metal 11b such as platinum dispersed on the surface of brown millerite particles,
This NOx catalyst porous material is fixed and formed in a metal container.
【００２４】更に、このＮＯｘ触媒多孔材の両端又は両
端近傍に電極３１ａ，３１ｂを設けると共に、この両電
極からＮＯｘ浄化触媒１１の導電率を計測する導電率計
測部３２を設け、この導電率計測部３２の計測値を、Ｅ
ＧＲバルブ２１を制御する制御部（制御手段）３０に入
力し、このＮＯｘ浄化触媒１１の導電率に基づいて、Ｅ
ＧＲバルブ２１の弁開度の制御を行うように構成する。Further, electrodes 31a and 31b are provided at or near both ends of the porous NOx catalyst, and a conductivity measuring section 32 for measuring the conductivity of the NOx purification catalyst 11 is provided from both electrodes. The measured value of the unit 32 is
It is input to a control unit (control means) 30 for controlling the GR valve 21, and based on the conductivity of the NOx purification catalyst 11, E
The opening degree of the GR valve 21 is controlled.
【００２５】このＮＯｘ浄化触媒１１の排気ガス通過時
の導電率を検知することにより、ＮＯｘ浄化触媒１１の
ＮＯｘの吸収量を知ることができるので、ＮＯｘ浄化触
媒１１の導電率に基づいて制御することにより、ＮＯｘ
浄化触媒１１からのＮＯｘの放出量に対応した制御をす
ることができる。By detecting the conductivity of the NOx purification catalyst 11 when the exhaust gas passes, the amount of NOx absorbed by the NOx purification catalyst 11 can be known. Therefore, the control is performed based on the conductivity of the NOx purification catalyst 11. NOx
Control corresponding to the amount of NOx released from the purification catalyst 11 can be performed.
【００２６】このＮＯｘ浄化触媒１１における導電率計
測部３２の構成は、図１の構成以外のものでも良く、例
えば、ＮＯｘ触媒多孔材の外周２カ所に電極膜を形成
し、この電極膜に外部電極を接続して、この外部電極か
らＮＯｘ浄化触媒１１の導電率を計測するようにして形
成してもよい。The configuration of the conductivity measuring section 32 in the NOx purification catalyst 11 may be other than the configuration shown in FIG. 1. For example, an electrode film is formed at two locations on the outer periphery of the NOx catalyst porous material, The electrodes may be connected so that the conductivity of the NOx purification catalyst 11 is measured from this external electrode.
【００２７】そして、ＮＯｘ浄化触媒１１を加熱して再
生するための加熱装置１２をＮＯｘ浄化触媒１１の外周
に配置し、この加熱装置１２でＮＯｘ浄化触媒１１を加
熱することにより、ＮＯｘ浄化触媒１１のブラウンミラ
ライト型複合酸化物１１ａに吸収されたＮＯｘを効率よ
く分解および放出させ、貴金属１１ｂの触媒作用により
還元及び分解し、ＮＯｘ浄化触媒１１を再生する。A heating device 12 for heating and regenerating the NOx purification catalyst 11 is arranged on the outer periphery of the NOx purification catalyst 11, and the heating device 12 heats the NOx purification catalyst 11. NOx absorbed by the brown-millarite-type composite oxide 11a is efficiently decomposed and released, and reduced and decomposed by the catalytic action of the noble metal 11b to regenerate the NOx purification catalyst 11.
【００２８】この加熱装置１２は、直接加熱する電気ヒ
ータ等や、マイクロ波や低温（（非平衡）プラズマ等に
よる誘導加熱を行う装置等で形成する。The heating device 12 is formed by an electric heater or the like for directly heating, or a device for performing induction heating by microwave or low-temperature ((non-equilibrium) plasma).
【００２９】そして、制御部３０は、加熱装置１２でＮ
Ｏｘ浄化触媒１１を加熱して再生する際に、通常のエン
ジン回転数、負荷に応じて設定されるＥＧＲバルブ２１
の弁開度よりも大きい弁開度を取るように、ＥＧＲバル
ブ２１の開閉制御信号を修正する。Then, the control unit 30 controls the heating device 12
When the Ox purification catalyst 11 is heated and regenerated, the EGR valve 21 set according to the normal engine speed and load is used.
The opening / closing control signal of the EGR valve 21 is corrected so that the valve opening degree is larger than the valve opening degree.
【００３０】つまり、従来のエンジン回転数、負荷に応
じて設定される弁開度に加えて、吸収しているＮＯｘ量
に応じて変化するＮＯｘ浄化触媒１１の導電率（抵抗
率）をＥＧＲバルブ２１の開閉弁制御のパラメータに加
えてＥＧＲバルブ２１の制御を行う。That is, in addition to the conventional valve opening set according to the engine speed and the load, the conductivity (resistivity) of the NOx purification catalyst 11 that changes according to the amount of NOx absorbed is determined by the EGR valve. The EGR valve 21 is controlled in addition to the on / off valve control parameters of the EGR valve 21.
【００３１】この構成の排気ガス浄化システム１によれ
ば、加熱装置１２の作動により、ＮＯｘ浄化触媒１１を
加熱昇温させて、このＮＯｘ浄化触媒１１のブラウンミ
ラライト型複合酸化物１１ａに吸収されたＮＯｘを分解
および放出させると共に、加熱昇温により活性化してい
る貴金属１１ｂの触媒作用により、放出されたＮＯｘを
還元浄化して、ＮＯｘ浄化触媒１１を再生することがで
きる。According to the exhaust gas purification system 1 having this configuration, the NOx purification catalyst 11 is heated and heated by the operation of the heating device 12 and is absorbed by the brown-millerite type composite oxide 11a of the NOx purification catalyst 11. The decomposed NOx is decomposed and released, and the released NOx is reduced and purified by the catalytic action of the precious metal 11b activated by heating to increase the temperature of the NOx purification catalyst 11.
【００３２】この加熱装置１２の作動によるＮＯｘの分
解および放出で、ブラウンミラライト型複合酸化物１１
ａのＮＯｘ吸収能力を回復させることができるので、Ｎ
Ｏｘ浄化触媒１１のＮＯｘの浄化能力の維持と耐久性向
上を図れる。The decomposition and release of NOx by the operation of the heating device 12 causes the brown-millerite type composite oxide 11
a, the NOx absorption capacity of
The NOx purification ability of the Ox purification catalyst 11 can be maintained and the durability can be improved.
【００３３】また、ＮＯｘ放出量を増加させた時に、Ｅ
ＧＲ弁２１の弁開度を大きくして、ＮＯｘ浄化触媒１１
のＮＯｘ浄化触媒から放出され、分解されずにＮＯｘ浄
化触媒１１を通過したＮＯｘをＥＧＲバルブ２１を介し
てエンジン１に戻し、このＮＯｘ濃度が高いＥＧＲガス
Ｇｅを燃焼させることでＮＯｘを還元できるので、ＮＯ
ｘ浄化率の低下を防止できる。When the NOx release amount is increased, E
By increasing the valve opening of the GR valve 21, the NOx purification catalyst 11
NOx released from the NOx purification catalyst and passed through the NOx purification catalyst 11 without being decomposed is returned to the engine 1 through the EGR valve 21, and NOx can be reduced by burning the EGR gas Ge having a high NOx concentration. , NO
x A reduction in purification rate can be prevented.
【００３４】また、従来のエンジン回転数、負荷に応じ
て設定される弁開度に加えて、ＮＯｘ量に応じて変化す
るＮＯｘ浄化触媒１１の導電率（抵抗率）を、ＥＧＲバ
ルブ２１の開閉弁制御のパラメータに加えてＥＧＲバル
ブ２１の制御を行うので、ＮＯｘ触媒１１のＮＯｘ除去
のより極め細かい制御が可能となり、外部に排出される
ＮＯｘ量の低減ができる。Further, in addition to the conventional valve opening set according to the engine speed and the load, the conductivity (resistivity) of the NOx purification catalyst 11 which changes according to the NOx amount is determined by opening and closing the EGR valve 21. Since the EGR valve 21 is controlled in addition to the valve control parameters, more precise control of the NOx removal of the NOx catalyst 11 can be performed, and the amount of NOx discharged to the outside can be reduced.
【００３５】[0035]
【発明の効果】以上に説明したように、本発明に係る排
気ガス浄化システムによれば、加熱装置等で形成される
再生手段を設けているので、ＮＯｘ浄化触媒を加熱昇温
させて、このＮＯｘ浄化触媒に吸収されたＮＯｘを分解
および放出させると共に、この放出されたＮＯｘを加熱
昇温により活性化している貴金属の触媒作用で効率よく
還元浄化し、ＮＯｘ浄化触媒を再生することができる。As described above, according to the exhaust gas purifying system of the present invention, since the regenerating means formed by the heating device or the like is provided, the NOx purifying catalyst is heated and heated. The NOx absorbed in the NOx purification catalyst is decomposed and released, and the released NOx is efficiently reduced and purified by the catalytic action of the noble metal activated by heating and raising the temperature, whereby the NOx purification catalyst can be regenerated.
【００３６】そして、再生手段によりＮＯｘ浄化触媒を
再生し、ＮＯｘ浄化触媒の浄化能力の維持と耐久性向上
を図ると共に、ＮＯｘ浄化触媒の再生時やＮＯｘ吸収能
力ガ低下した時に、ＮＯｘ浄化触媒から放出され、分解
されずにＮＯｘ浄化触媒を通過したＮＯｘをＥＧＲガス
還流通路経由でエンジンに戻して、このＮＯｘ濃度が高
いＥＧＲガスを燃焼させて放出されたＮＯｘを還元浄化
できるので、外部に排出される排ガスにおけるＮＯｘ浄
化率の低下を防止できる。The NOx purifying catalyst is regenerated by the regenerating means to maintain the purifying ability of the NOx purifying catalyst and to improve the durability. When the NOx purifying catalyst is regenerated or the NOx absorbing capacity is reduced, the NOx purifying catalyst is regenerated. The NOx that has been released and passed through the NOx purification catalyst without being decomposed is returned to the engine via the EGR gas recirculation passage, and the released NOx can be reduced and purified by burning the EGR gas having a high NOx concentration, so that it is discharged to the outside. It is possible to prevent a decrease in the NOx purification rate of the exhaust gas to be discharged.
【図１】本発明に係る実施の形態の排気ガス浄化システ
ムの構成を示す図である。FIG. 1 is a diagram showing a configuration of an exhaust gas purification system according to an embodiment of the present invention.
１ エンジン ３ 排気通路 １０ 排気ガス浄化システム １１ ＮＯｘ浄化触媒 １１ａ ブラウンミラライト型複合酸化物 １１ｂ 貴金属 １２ 再生手段（加熱装置） ２０ ＥＧＲガス還流通路 ２０ｂ ＥＧＲガス還流通路が分岐する位置 ２１ ＥＧＲバルブ ３２ 導電率計測部 ３０ 制御手段（制御部） Ｇ 排気ガス DESCRIPTION OF SYMBOLS 1 Engine 3 Exhaust passage 10 Exhaust gas purification system 11 NOx purification catalyst 11a Brown Miralite type complex oxide 11b Noble metal 12 Regeneration means (heating device) 20 EGR gas recirculation passage 20b Position where EGR gas recirculation passage branches 21 EGR valve 32 Conduction Rate measuring unit 30 Control means (control unit) G Exhaust gas
フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｆ０１Ｎ 3/10 Ｆ０１Ｎ 3/10 Ｚ 3/20 Ｂ 3/20 Ｆ０２Ｍ 25/07 ５５０Ｒ Ｆ０２Ｍ 25/07 ５５０ ５８０Ａ ５８０ ５８０Ｆ Ｂ０１Ｄ 53/36 １０１Ａ Ｆターム(参考） 3G062 CA06 ED01 GA00 GA01 GA06 3G091 AA11 AA17 AA18 AB09 BA14 CA01 CA03 GA06 GB02W GB03W GB04W GB06W HA45 HB05 4D048 AA05 BA14X BA15X BA18X BA30X BA31X BA32X BA33X BA34X BD01 CC27 CC53 DA02 DA08 EA03 4G066 AA02D AA12B AA13B AA16B AA17B AA22B AA39B AA66C BA32 CA28 DA02 GA02 GA03Continued on the front page (51) Int.Cl. 7 Identification symbol FI Theme coat II (Reference) F01N 3/10 F01N 3/10 Z 3/20 B 3/20 F02M 25/07 550R F02M 25/07 550 580A 580 580F B01D 53/36 101A F-term (reference) 3G062 CA06 ED01 GA00 GA01 GA06 3G091 AA11 AA17 AA18 AB09 BA14 CA01 CA03 GA06 GB02W GB03W GB04W GB06W HA45 HB05 4D048 AA05 BA14X BA15X BA18X BA30X BA31X BA32X BA33ABAAA DAB ABAXA33A02 AA16B AA17B AA22B AA39B AA66C BA32 CA28 DA02 GA02 GA03
Claims (5)
路を備えたエンジンにおいて、排気ガス中のＮＯｘを吸
収及び分解するＮＯｘ浄化触媒と、該ＮＯｘ浄化触媒に
吸収されたＮＯｘを分解し、該ＮＯｘ浄化触媒を再生す
るための再生手段とを有して形成されるＮＯｘ浄化装置
を、前記ＥＧＲガス還流通路が分岐する位置よりも上流
側の排気通路に設けたことを特徴とする排気ガス浄化シ
ステム。In an engine provided with an EGR gas recirculation passage having an EGR valve, a NOx purification catalyst that absorbs and decomposes NOx in exhaust gas, and decomposes NOx absorbed by the NOx purification catalyst to purify the NOx An exhaust gas purification system, characterized in that a NOx purification device formed having regeneration means for regenerating a catalyst is provided in an exhaust passage upstream of a position where the EGR gas recirculation passage branches.
媒のＮＯｘ浄化触媒の導電率を計測する導電率計測部を
設けると共に、該導電率計測部で計測されたＮＯｘ浄化
触媒の導電率に基づいて、前記ＥＧＲバルブの弁開度の
制御を行う制御手段を備えたことを特徴とする請求項１
記載の排気ガス浄化システム。2. A method according to claim 1, wherein said NOx purification catalyst is provided with a conductivity measuring section for measuring the conductivity of said NOx purification catalyst, and based on the conductivity of said NOx purification catalyst measured by said conductivity measuring section. A control means for controlling a valve opening of the EGR valve.
An exhaust gas purification system as described.
ルカリ土類金属元素、アルカリ金属元素の内、少なくと
も１種類以上の元素を含有するブラウンミラライト型複
合酸化物と、ブラウンミラライト粒子表面に分散した貴
金属とからなることを特徴とする請求項１又は２に記載
の排気ガス浄化システム。3. A brown-millerite-type composite oxide containing at least one element selected from the group consisting of a rare-earth element, an alkaline-earth metal element, and an alkali metal element, The exhaust gas purification system according to claim 1, comprising a dispersed noble metal.
Ｏｘ浄化触媒を再生する際に、前記ＥＧＲバルブの弁開
度を修正することを特徴とする請求項１〜３のいずれか
１項に記載の排気ガス浄化システム。4. The control means according to claim 1, wherein:
The exhaust gas purification system according to any one of claims 1 to 3, wherein a valve opening of the EGR valve is corrected when the Ox purification catalyst is regenerated.
加熱する加熱装置で形成すると共に、該加熱装置を、直
接加熱する電気ヒータ、マイクロ波又は低温プラズマに
よる誘導加熱を行う加熱装置のいずれか一つ又は組合せ
で形成することを特徴とする請求項１〜４のいずれか１
項に記載の排気ガス浄化システム。5. The regenerating means is formed of a heating device that heats the NOx purification catalyst, and the heating device is any one of an electric heater that directly heats the heating device, and a heating device that performs induction heating by microwave or low-temperature plasma. 5. A method according to claim 1, wherein said one or a combination is formed.
The exhaust gas purification system according to the paragraph.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001153716A JP4411799B2 (en) | 2001-05-23 | 2001-05-23 | Exhaust gas purification system |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001153716A JP4411799B2 (en) | 2001-05-23 | 2001-05-23 | Exhaust gas purification system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2002349252A true JP2002349252A (en) | 2002-12-04 |
| JP4411799B2 JP4411799B2 (en) | 2010-02-10 |
Family
ID=18998191
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001153716A Expired - Fee Related JP4411799B2 (en) | 2001-05-23 | 2001-05-23 | Exhaust gas purification system |
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| Country | Link |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009041641A1 (en) * | 2007-09-27 | 2009-04-02 | Toyota Jidosha Kabushiki Kaisha | Exhaust purification system for internal combustion engine |
| CN115155307A (en) * | 2022-07-20 | 2022-10-11 | 上海理工大学 | Low-temperature plasma coupled manganese-cerium-titanium catalyst for stably and efficiently removing NO x Method (2) |
-
2001
- 2001-05-23 JP JP2001153716A patent/JP4411799B2/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009041641A1 (en) * | 2007-09-27 | 2009-04-02 | Toyota Jidosha Kabushiki Kaisha | Exhaust purification system for internal combustion engine |
| US8402753B2 (en) | 2007-09-27 | 2013-03-26 | Toyota Jidosha Kabushiki Kaisha | Exhaust gas purification system for an internal combustion engine |
| CN115155307A (en) * | 2022-07-20 | 2022-10-11 | 上海理工大学 | Low-temperature plasma coupled manganese-cerium-titanium catalyst for stably and efficiently removing NO x Method (2) |
| CN115155307B (en) * | 2022-07-20 | 2023-11-03 | 上海理工大学 | Low-temperature plasma coupling manganese-cerium-titanium catalyst for stably and efficiently removing NO x Is a method of (2) |
Also Published As
| Publication number | Publication date |
|---|---|
| JP4411799B2 (en) | 2010-02-10 |
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