JP2005042687A - Exhaust emission control device and emission control method - Google Patents

Exhaust emission control device and emission control method Download PDF

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JP2005042687A
JP2005042687A JP2003280391A JP2003280391A JP2005042687A JP 2005042687 A JP2005042687 A JP 2005042687A JP 2003280391 A JP2003280391 A JP 2003280391A JP 2003280391 A JP2003280391 A JP 2003280391A JP 2005042687 A JP2005042687 A JP 2005042687A
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exhaust gas
filter
ceramic honeycomb
inflow side
catalyst
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JP4412641B2 (en
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Hirohisa Suwabe
博久 諏訪部
Hiroshi Funahashi
博 舟橋
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Hino Motors Ltd
Proterial Ltd
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Hino Motors Ltd
Hitachi Metals Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/033—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices
    • F01N3/035—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices with catalytic reactors, e.g. catalysed diesel particulate filters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2340/00—Dimensional characteristics of the exhaust system, e.g. length, diameter or volume of the apparatus; Spatial arrangements of exhaust apparatuses
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2510/00—Surface coverings
    • F01N2510/06—Surface coverings for exhaust purification, e.g. catalytic reaction
    • F01N2510/068—Surface coverings for exhaust purification, e.g. catalytic reaction characterised by the distribution of the catalytic coatings
    • F01N2510/0682—Surface coverings for exhaust purification, e.g. catalytic reaction characterised by the distribution of the catalytic coatings having a discontinuous, uneven or partially overlapping coating of catalytic material, e.g. higher amount of material upstream than downstream or vice versa
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/023—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles
    • F01N3/0231—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles using special exhaust apparatus upstream of the filter for producing nitrogen dioxide, e.g. for continuous filter regeneration systems [CRT]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/103—Oxidation catalysts for HC and CO only
    • 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

<P>PROBLEM TO BE SOLVED: To provide a compact exhaust emission control device and an exhaust emission control method, which efficiently remove NOx and particulate substance contained in exhaust gas, in the exhaust emission control device of a diesel engine and which can reduce pressure loss in the whole exhaust emission control device. <P>SOLUTION: The exhaust emission control device is constructed such that a filter and a SCR (Selective Catalytic Reduction) catalyst are arranged in this order from an upstream side in an exhaust passage of the diesel engine. The ceramic honeycomb filter has a porous ceramic honeycomb structure in which desired flow passages are sealed. At least one sealed portion on an exhaust gas inflow side of the filter is arranged apart from an exhaust gas inflow side end surface. Catalyst material is carried on at least a part of partition walls and/or the sealed portions. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、ディーゼルエンジンから排出される、窒素酸化物（以下ＮＯxとも略記する）及び粒子状物質を含有する排気ガスを浄化するディーゼルエンジンの排気ガス浄化装置に関するものである。 The present invention is discharged from a diesel engine, to a exhaust gas purifying device for a diesel engine for purifying nitrogen oxides (also hereinafter NO x abbreviated) and an exhaust gas containing particulate matter.

ディーゼルエンジンはその燃費効率の高さから、欧州を中心に需要が増大している。しかしながら、ディーゼルエンジンの排気ガス中に含まれている粒子状物質（ＰＭ：Particulate Matter）及び窒素酸化物（ＮＯx）の人体の健康に与える影響が大きいことから、このＰＭ及びＮＯxの低減技術が種々検討されている。この排気ガス中のＰＭ及びＮＯxを低減する排気ガス浄化装置として、例えば、特許文献１に記載の発明には、ＮＯ及び粒子状物質を含む燃焼排気ガスを処理する改良されたＳＣＲ（Ｓｅｌｅｃｔｉｖｅ Ｃａｔａｌｙｔｉｃ Ｒｅｄｕｃｔｉｏｎ）機構であって、前記ＮＯx中のＮＯの少なくとも一部をＮＯ２に効果的に転化する酸化触媒と、粒子状物質トラップと、還元剤流体の供給源、及びＳＣＲ触媒をこの順序で組み合わせてなる、ＳＣＲ機構が開示されている。ここでＳＣＲとは、選択的接触還元のことで、高温の排気ガスを、窒素系還元剤、特にアンモニアまたは、尿素の存在下で触媒上を通過させる方法である。この発明では、酸化触媒により排気ガス中のＮＯがＮＯ２に効果的に転化され、粒子状物質トラップで排気ガス中の粒子状物質の少なくとも一部がＮＯ２の存在下で比較的低い温度で燃焼除去される。更に、ＮＯ２含有量の高くなった排気ガスに対して、窒素系還元剤を添加してガス混合物を形成し、このガス混合物をＳＣＲ触媒上に通過させることにより、ＮＯｘがＮ２に転化される。この発明によれば、ＳＣＲ触媒の上流に配置した酸化触媒、及び粒子状物質トラップが、ＳＣＲ機構によるＮＯxからＮ２への転化率を増加するのに特に有効であるとされている。この発明では、酸化触媒には、例えば、セラミックまたは金属製の、スルー−フローハニカム担体上に担持された白金触媒が特に好適とされており、粒子状物質トラップには、一般的にセラミックから製造されるウオール−フローフィルターが好ましいとされ、ＳＣＲ触媒には、スルー−フローハニカム担体上に担持されたＶ２Ｏ５／ＷＯ３／ＴｉＯ２触媒が好ましいとされている。 Demand for diesel engines is increasing mainly in Europe due to its high fuel efficiency. However, since PM (Particulate Matter) and nitrogen oxide (NO x ) contained in the exhaust gas of diesel engines have a great influence on human health, this PM and NO x reduction technology Various studies have been made. As an exhaust gas purifying device for reducing PM and NO x in the exhaust gas, for example, the invention described in Patent Document 1 includes an improved SCR (Selective Catalytic) for treating combustion exhaust gas containing NO and particulate matter. Reduction mechanism, in which an oxidation catalyst that effectively converts at least a portion of NO in the NO x into NO 2 , a particulate matter trap, a source of reducing agent fluid, and an SCR catalyst in this order. A combined SCR mechanism is disclosed. Here, SCR refers to selective catalytic reduction, which is a method in which high-temperature exhaust gas is passed over a catalyst in the presence of a nitrogen-based reducing agent, particularly ammonia or urea. In the present invention, NO in the exhaust gas is effectively converted to NO 2 by the oxidation catalyst, and at least a part of the particulate matter in the exhaust gas is at a relatively low temperature in the presence of NO 2 by the particulate matter trap. Burned away. Further, a nitrogen-based reducing agent is added to the exhaust gas having a high NO 2 content to form a gas mixture, and this gas mixture is passed over the SCR catalyst, so that NO x is converted to N 2 . Is done. According to the present invention, the oxidation catalyst disposed upstream of the SCR catalyst and the particulate matter trap are considered to be particularly effective in increasing the conversion rate from NO x to N 2 by the SCR mechanism. In this invention, a platinum catalyst supported on a through-flow honeycomb carrier made of, for example, ceramic or metal is particularly suitable as the oxidation catalyst, and the particulate matter trap is generally manufactured from ceramic. The wall-flow filter is preferred, and the SCR catalyst is preferably a V 2 O 5 / WO 3 / TiO 2 catalyst supported on a through-flow honeycomb carrier.

また、特許文献２に記載の発明には、図４にこの発明に係わる実施の形態のディーゼルエンジンの排気ガス浄化装置を示すエンジンの排気系の構成図を示すように、ディーゼルエンジンの排気通路２に、ＮＯｘを還元浄化するＳＣＲ触媒５を配設すると共に、該ＳＣＲ触媒の上流側に、上流側から順に酸化触媒３と、該酸化触媒３の触媒作用により排気ガス中の硫黄分が酸化されて生じるサルフェート分を捕集できるフィルタ４を直列に配設したことを特徴とするディーゼルエンジンの排気ガス浄化装置が開示されている。そして、フィルタ４とＳＣＲ触媒５の間の排気通路２に還元剤供給装置６が設けてある。この発明の構成によれば、排気ガス中に含まれる硫黄分を排気ガス中のダストと共に捕集し、下流側のＳＣＲ触媒５が硫黄分やＰＭ等のダストにより、被毒するのを防止できるので、効率よくＮＯｘを還元浄化でき、排気ガスによる公害を低減できるとしている。この発明において、酸化触媒３は、例えば、コージェライト製モノリス担体にアルミナの触媒担持層をコーティングにより形成し、この担持層に白金等の触媒成分を担持させたものが使用され、フィルタ４は、多数の排気通路が互いに平行に形成されたコージェライト製のハニカムフィルタやアルミナ等のセラミック不織布からなるフィルタ等を使用することができ、更に、ＳＣＲ触媒５は、担体をＡｌ２Ｏ３、ＴｉＯ２等で形成し、活性体として触媒金属をＰｔ、Ｖ２Ｏ５、Ｆｅ２Ｏ３、ＣｕＯ、Ｍｎ２Ｏ３、Ｃｒ２Ｏ３、ＭｏＯ３等で形成する。 Further, in the invention described in Patent Document 2, the exhaust passage 2 of the diesel engine is shown in FIG. 4 as a configuration diagram of the exhaust system of the engine showing the exhaust gas purifying device of the diesel engine of the embodiment according to the present invention. In addition, an SCR catalyst 5 for reducing and purifying NO x is disposed, and the upstream side of the SCR catalyst is oxidized in order from the upstream side, and the sulfur content in the exhaust gas is oxidized by the catalytic action of the oxidation catalyst 3. An exhaust gas purification device for a diesel engine is disclosed, in which a filter 4 capable of collecting the generated sulfate is arranged in series. A reducing agent supply device 6 is provided in the exhaust passage 2 between the filter 4 and the SCR catalyst 5. According to the configuration of the present invention, the sulfur content contained in the exhaust gas can be collected together with the dust in the exhaust gas, and the downstream SCR catalyst 5 can be prevented from being poisoned by dust such as the sulfur content and PM. so it can be efficiently reduce and purify NO x, are the pollution can be reduced by the exhaust gas. In the present invention, the oxidation catalyst 3 is, for example, a cordierite monolith support formed by coating a catalyst support layer of alumina and supporting a catalyst component such as platinum on the support layer. A cordierite honeycomb filter in which a large number of exhaust passages are formed in parallel with each other, a filter made of a ceramic nonwoven fabric such as alumina, or the like can be used. Further, the SCR catalyst 5 uses Al 2 O 3 , TiO 2 as a carrier. The catalyst metal is formed of Pt, V 2 O 5 , Fe 2 O 3 , CuO, Mn 2 O 3 , Cr 2 O 3 , MoO 3 or the like as an active substance.

特表２００２−５０２９２７号公報Japanese translation of PCT publication No. 2002-502927 特開２０００−３０３８２６号公報JP 2000-303826 A

上記従来技術である特許文献１及び２に記載されているディーゼルエンジンから排出される排気ガスの浄化装置では、排気ガス通路に、酸化触媒、フィルタ、還元剤流体の供給源、及びＳＣＲ触媒の各装置が直列に配置されており、多くの場合、酸化触媒及びＳＣＲ触媒には触媒物質が担持されたセラミックハニカム構造体が、またフィルタにはセラミックハニカム構造体の所望の流路を両端部で目封止したセラミックハニカムフィルタ、或いはセラミック不織布からなるフィルタ等が使用されている。このため、排気ガス浄化装置の圧力損失は、２種類のハニカム構造体の圧力損失、セラミックハニカムフィルタ、又はセラミック不織布からなるフィルタの圧力損失が加算されたものとなり、装置全体の圧力損失が大きくなって、エンジン出力や燃費の低下につながるという問題がある。また、例えば特許文献２の図２に記載されているような、従来の排気ガス浄化装置では、酸化触媒とフィルタが排気通路によって、直列に配置されていることから、酸化触媒における触媒反応により高温となった排気ガスが、酸化触媒とフィルタ間の排気通路を通過する間に温度が低下してフィルタに流入し、特に低速走行時のように浄化装置に流入する排気ガス温度自体が低い場合は、フィルタ内の温度が、粒子状物質を十分に燃焼させる温度に達しない場合があり、未燃焼の粒子状物質がフィルタに残存して、フィルタの圧力損失が上昇するという問題の発生する場合もあった。   In the apparatus for purifying exhaust gas discharged from the diesel engine described in Patent Documents 1 and 2 which are the above-described prior art, each of the oxidation catalyst, the filter, the reducing agent fluid supply source, and the SCR catalyst is provided in the exhaust gas passage. The devices are arranged in series. In many cases, the oxidation catalyst and the SCR catalyst have a ceramic honeycomb structure in which a catalyst material is supported, and the filter has a desired flow path of the ceramic honeycomb structure at both ends. Sealed ceramic honeycomb filters or filters made of ceramic nonwoven fabric are used. For this reason, the pressure loss of the exhaust gas purification device is the sum of the pressure loss of two types of honeycomb structures, the pressure loss of a filter made of a ceramic honeycomb filter or a ceramic nonwoven fabric, and the pressure loss of the entire device increases. As a result, there is a problem that the engine output and fuel consumption are reduced. Further, in the conventional exhaust gas purifying apparatus as described in FIG. 2 of Patent Document 2, for example, the oxidation catalyst and the filter are arranged in series by the exhaust passage, so that a high temperature is caused by the catalytic reaction in the oxidation catalyst. When the exhaust gas that has become lower in temperature passes through the exhaust passage between the oxidation catalyst and the filter and flows into the filter, especially when the exhaust gas temperature itself flowing into the purification device is low, such as during low-speed running In some cases, the temperature in the filter may not reach the temperature at which the particulate matter is sufficiently combusted, and unburned particulate matter may remain in the filter, resulting in an increase in the pressure loss of the filter. there were.

また、ハニカム構造体やセラミックハニカムフィルタ又はセラミック不織布からなるフィルタ等の装置は、浄化性能を確保するために一定量の体積が必要であることから、従来技術のように２種類のハニカム構造体、セラミックハニカムフィルタ又はセラミック不織布からなるフィルタ、及び還元剤供給装置の４種類の装置を直列に配置した場合、取り付けスペースが膨大になり、例えばディーゼル車輌への搭載が困難になるという問題もあり、小型で低圧力損失、且つ高効率の排気ガス浄化装置が求められていた。
本発明の目的は、上記従来技術の問題を解決し、小型で低圧力損失の排気ガス浄化装置を提供することにある。 In addition, a device such as a honeycomb structure, a ceramic honeycomb filter or a filter made of a ceramic nonwoven fabric requires a certain amount of volume in order to ensure purification performance. When four types of devices, a ceramic honeycomb filter or a filter made of ceramic nonwoven fabric, and a reducing agent supply device are arranged in series, the mounting space becomes enormous, and there is a problem that mounting on a diesel vehicle becomes difficult, for example. Therefore, there has been a demand for an exhaust gas purifying apparatus with low pressure loss and high efficiency.
An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a small exhaust gas purifying device with low pressure loss.

本発明者らは、排気ガス中のＮＯxと粒子状物質を効果的に低減しつつ、排気ガス浄化装置全体の圧力損失の低減及び小型化について、鋭意検討を行った結果、ＳＣＲ触媒の上流に配置される、フィルタの構造を最適化することが有効であることを見出し、本発明に想到した。 As a result of diligent research on reducing the pressure loss and downsizing of the entire exhaust gas purification device while effectively reducing NO x and particulate matter in the exhaust gas, the present inventors have found that the upstream of the SCR catalyst. The present inventors have found that it is effective to optimize the structure of the filter arranged in the above, and have arrived at the present invention.

本発明の排気ガス浄化装置は、ディーゼルエンジンから排出される窒素酸化物及び粒子状物質を含有する排気ガスを浄化する装置であって、多孔質セラミックハニカム構造体の所望の流路を目封止したセラミックハニカムフィルタの、少なくとも一つの排気ガス流入側目封止部が排気ガス流入側端面より離れて配置されていると共に、隔壁及び／または目封止部の少なくとも一部に触媒物質が担持されているフィルタと、ＳＣＲ触媒とを、この順序で配置したことを特徴とする。   The exhaust gas purifying apparatus of the present invention is an apparatus for purifying exhaust gas containing nitrogen oxides and particulate matter discharged from a diesel engine, and plugs a desired flow path of a porous ceramic honeycomb structure. In the ceramic honeycomb filter, at least one exhaust gas inflow side plugged portion is disposed away from the end surface of the exhaust gas inflow side, and a catalyst substance is supported on at least a part of the partition wall and / or the plugged portion. The filter and the SCR catalyst are arranged in this order.

さらに本発明の排気ガス浄化装置において、前記セラミックハニカムフィルタの排気ガス流入側目封止部端面が、セラミックハニカムフィルタの流入側端面から該セラミックハニカムフィルタ全長の０．７倍以下の長さの区間に配置されていることが好ましい。また、前記セラミックハニカムフィルタに担持される触媒物質が白金族金属を含んでなることが好ましい。更には、前記セラミックハニカムフィルタに担持される触媒物質を、排気ガス流出側に比べ排気ガス流入側に多く担時させることが好ましい。   Furthermore, in the exhaust gas purifying apparatus of the present invention, the end face of the exhaust gas inflow side plugging portion of the ceramic honeycomb filter is a section having a length not more than 0.7 times the total length of the ceramic honeycomb filter from the inflow side end face of the ceramic honeycomb filter. It is preferable to arrange | position. Further, it is preferable that the catalyst material supported on the ceramic honeycomb filter contains a platinum group metal. Furthermore, it is preferable that a larger amount of the catalyst material supported on the ceramic honeycomb filter is carried on the exhaust gas inflow side than on the exhaust gas outflow side.

本発明の排気ガス浄化方法は、ディーゼルエンジンから排出される窒素酸化物及び粒子状物質を含有する排気ガスを浄化する装置に配設されたセラミックハニカムフィルタの、少なくとも一つの排気ガス流入側目封止部が排気ガス流入側端面より離れて配置されていると共に、隔壁及び／または目封止部の少なくとも一部に触媒物質が担持され、前記排気ガス中の粒子状物質を前記セラミックハニカムフィルタ内で燃焼させ、前記フィルタの排気ガス排出側に配設されたＳＣＲ触媒中に導入する排気ガス中のＮＯ／ＮＯ２のモル比を１／２〜２／１にすることを特徴とする。 The exhaust gas purification method of the present invention includes at least one exhaust gas inflow side plugging of a ceramic honeycomb filter disposed in a device for purifying exhaust gas containing nitrogen oxides and particulate matter discharged from a diesel engine. The stop portion is disposed away from the end surface on the exhaust gas inflow side, and a catalyst substance is supported on at least a part of the partition wall and / or the plugging portion, and particulate matter in the exhaust gas is contained in the ceramic honeycomb filter. And the molar ratio of NO / NO 2 in the exhaust gas introduced into the SCR catalyst disposed on the exhaust gas discharge side of the filter is set to 1/2 to 2/1.

本発明の排気ガス浄化装置及び排気ガス浄化方法の作用、効果について、本発明の排気ガス浄化装置を示すエンジンの排気系の構成図である図１を用いて説明する。
本発明のディーゼルエンジンから排出される窒素酸化物（ＮＯｘ）及び粒子状物質を含有する排気ガスを浄化する装置は、多孔質セラミックハニカム構造体の所望の流路を目封止したセラミックハニカムフィルタの、少なくとも一つの排気ガス流入側目封止部が排気ガス流入側端面より離れて配置されていると共に、隔壁及び／または目封止部の少なくとも一部に触媒物質が担持されているフィルタ１１と、ＳＣＲ触媒５とを、この順序で配置している。このため、酸化触媒、フィルタ、還元剤の供給源、ＳＣＲ触媒を、この順序で配置した従来技術の排気ガス浄化装置の圧力損失が、酸化触媒に用いられるハニカム構造体の圧力損失、セラミックハニカムフィルタ、又はセラミック不織布からなるフィルタの圧力損失、及びＳＣＲ触媒に用いられるハニカム構造体の圧力損失の合計となり、装置全体の圧力損失が大きくなっているのに対し、本発明の排気ガス浄化装置の圧力損失は、セラミックハニカムフィルタの圧力損失とＳＣＲ触媒に用いられるハニカム構造体の圧力損失の合計にすぎないので、排気ガス通路全体の圧力損失を小さくすることができ、エンジン出力や燃費の低下を防ぐことができるのと共に、排ガス浄化装置全体の小型化が可能となる。 The operation and effect of the exhaust gas purification apparatus and the exhaust gas purification method of the present invention will be described with reference to FIG. 1 which is a configuration diagram of an engine exhaust system showing the exhaust gas purification apparatus of the present invention.
An apparatus for purifying exhaust gas containing nitrogen oxide (NO x ) and particulate matter discharged from a diesel engine of the present invention is a ceramic honeycomb filter in which a desired flow path of a porous ceramic honeycomb structure is plugged. The filter 11 has at least one exhaust gas inflow side plugging portion disposed away from the exhaust gas inflow side end surface, and at least a part of the partition wall and / or the plugging portion carries a catalyst substance. And the SCR catalyst 5 are arranged in this order. For this reason, the pressure loss of the exhaust gas purification device of the prior art in which the oxidation catalyst, the filter, the reducing agent supply source, and the SCR catalyst are arranged in this order is the pressure loss of the honeycomb structure used for the oxidation catalyst, the ceramic honeycomb filter Or the pressure loss of the filter made of the ceramic nonwoven fabric and the pressure loss of the honeycomb structure used for the SCR catalyst, and the pressure loss of the entire apparatus is large, whereas the pressure of the exhaust gas purification apparatus of the present invention Since the loss is only the sum of the pressure loss of the ceramic honeycomb filter and the pressure loss of the honeycomb structure used for the SCR catalyst, the pressure loss of the entire exhaust gas passage can be reduced, and the engine output and fuel consumption are prevented from being lowered. In addition, the entire exhaust gas purification device can be reduced in size.

ここで、本発明の排気ガス浄化装置において、多孔質セラミックハニカム構造体の所望の流路を目封止したセラミックハニカムフィルタの、少なくとも一つの排気ガス流入側目封止部が排気ガス流入側端面より離れて配置されていると共に、隔壁及び／または目封止部の少なくとも一部に触媒物質が担持されているフィルタ１１を用いる理由と作用、効果について以下説明する。
図２は、本発明の排気ガス浄化装置に用いられるフィルタ１１の一例の模式断面図である。フィルタ１１は、流路方向垂直断面が略円状又は略楕円状で、外周壁２０と、この外周壁２０の内周側で隔壁３０により囲まれた多数の流路４０を有する多孔質セラミックハニカム構造体１０の流路４０の所望部位に目封止部５０、５２により交互に目封止している。そして、少なくとも一つの排気ガス流入側の目封止部端面５１は、セラミックハニカムフィルタの流入側端面１２に対して、排気ガス流出側に離れて配置されており、隔壁及び／または目封止部の少なくとも一部には触媒物質６０が担持されている。 Here, in the exhaust gas purification device of the present invention, at least one exhaust gas inflow side plugged portion of the ceramic honeycomb filter in which a desired flow path of the porous ceramic honeycomb structure is plugged is an exhaust gas inflow side end surface. The reason, function, and effect of using the filter 11 that is disposed further apart and that has a catalytic substance supported on at least a part of the partition walls and / or plugging portions will be described below.
FIG. 2 is a schematic cross-sectional view of an example of the filter 11 used in the exhaust gas purification apparatus of the present invention. The filter 11 has a porous ceramic honeycomb having a substantially vertical or substantially elliptical cross section in the flow path direction, an outer peripheral wall 20, and a large number of flow paths 40 surrounded by partition walls 30 on the inner peripheral side of the outer peripheral wall 20. The desired portions of the flow path 40 of the structure 10 are alternately plugged by plugging portions 50 and 52. At least one exhaust gas inflow side plugging portion end surface 51 is disposed away from the inflow side end surface 12 of the ceramic honeycomb filter on the exhaust gas outflow side, and the partition wall and / or the plugging portion At least a part of the catalyst material 60 is supported.

このような構造を有するハニカムフィルタにおいて排気ガスは、流入側端面１２で開口している流路４１、及び４２から流入する。このうち流路４２から流入した排気ガス９１は、流入側目封止部５０があることから、隔壁３１中に形成された細孔（図示せず）を通過して隣接する流路４１に排出され、この流路４１に流入側端面１２から流入した排気ガス９０と合流後、流路４１を流出側端面１３に向かって進行し、この流路の流出側端面には、流出側目封止部５２があるために、隔壁３２に形成された細孔（図示せず）を通過して隣接する流路である流出側端面１３で開口している流路４３から排出（矢印９２で示す）される。なお、排気ガスのうちの一部は、流入側目封止部５０及び流出側目封止部５２に形成されている細孔（図示せず）を通過して、排出されるものもある。この間、排気ガス中の粒子状物質は、主に流路４１〜４３、及び隔壁３１〜３２を通過する際に、多孔質隔壁に捕集されると共に、隔壁及び／または目封止部の少なくとも一部には端持された触媒物質の作用により燃焼され効率よく排気ガスが浄化される。   In the honeycomb filter having such a structure, exhaust gas flows from the flow paths 41 and 42 opened at the inflow side end face 12. Among these, the exhaust gas 91 that has flowed in from the flow path 42 passes through pores (not shown) formed in the partition wall 31 and is discharged to the adjacent flow path 41 because of the inflow side plugging portion 50. After joining the exhaust gas 90 flowing into the flow path 41 from the inflow side end face 12, the flow path 41 proceeds toward the outflow side end face 13, and the outflow side end face of the flow path has an outflow side plugging. Due to the presence of the portion 52, it passes through the pores (not shown) formed in the partition wall 32 and is discharged from the flow path 43 that is open at the outflow side end face 13 that is an adjacent flow path (indicated by an arrow 92). Is done. Note that some of the exhaust gas passes through pores (not shown) formed in the inflow side plugged portion 50 and the outflow side plugged portion 52 and is exhausted. During this time, the particulate matter in the exhaust gas is collected by the porous partition walls mainly when passing through the flow paths 41 to 43 and the partition walls 31 to 32, and at least the partition walls and / or the plugging portions. In part, the exhaust gas is efficiently purified by being burned by the action of the end-carrying catalyst substance.

従来技術では、排気ガス浄化装置の小型化ができないという問題に加えて、酸化触媒における触媒反応により高温となった排気ガスが、酸化触媒とフィルタ間の排気通路２を通過する際に温度が低下し、低温の排気ガスとなってフィルタに流入し、特に低速走行時のような浄化装置に流入する排気ガス温度自体が低い場合に、フィルタ内の温度が、粒子状物質を十分に燃焼させる温度に達せず、未燃焼の粒子状物質がフィルタに残存、特に未燃焼の粒子状物質が温度の低いフィルタ入口端部に多く残存して、流路を閉塞させることによるフィルタの圧力損失が上昇するという問題もあった。これに対して、本発明の排気ガス浄化装置は、少なくとも一つの流入側目封止部５０がセラミックハニカムフィルタ１１の流入側端面からフィルタ内部に離れて配置されていることから、排気ガスが流入側目封止部５０より流入側に配置された隔壁３１に担持された触媒物質による触媒反応により、高温とされるため、フィルタ内部の温度を前記触媒物質の活性下限温度以上に維持し易くなる。このため、本発明の排気ガス浄化装置は、排ガス中の粒子状物質を効率よく燃焼させることができ、特に流入側目封止部での未燃焼粒子状物質の堆積による圧力損失の上昇を防ぐことが出来るという効果も有する。   In the prior art, in addition to the problem that the exhaust gas purification device cannot be downsized, the temperature of the exhaust gas that has become high due to the catalytic reaction in the oxidation catalyst decreases when passing through the exhaust passage 2 between the oxidation catalyst and the filter. However, when the exhaust gas temperature that flows into the filter as low-temperature exhaust gas and flows into the purification device, such as when traveling at a low speed, is low, the temperature in the filter is such that the particulate matter is sufficiently combusted. The unburned particulate matter remains in the filter, and in particular, a large amount of unburned particulate matter remains at the filter inlet end where the temperature is low, and the pressure loss of the filter increases due to the blockage of the flow path. There was also a problem. On the other hand, in the exhaust gas purifying apparatus of the present invention, at least one inflow side plugging portion 50 is disposed away from the inflow side end face of the ceramic honeycomb filter 11 inside the filter, so that the exhaust gas flows in. Since the temperature is raised by the catalytic reaction by the catalytic material supported on the partition wall 31 arranged on the inflow side from the side plugging portion 50, the temperature inside the filter can be easily maintained at the activation lower limit temperature or more. . For this reason, the exhaust gas purification apparatus of the present invention can efficiently burn particulate matter in the exhaust gas, and in particular, prevents an increase in pressure loss due to accumulation of unburned particulate matter at the inflow side plugged portion. It also has the effect of being able to

さらに、従来技術である酸化触媒、フィルタ、還元剤の供給源、ＳＣＲ触媒の装置の組合せにより構成される排気ガス浄化装置に対して、上記のように、本発明の少なくとも一つの排気ガス流入側目封止部が排気ガス流入側端面より離れて配置されていると共に、隔壁及び／または目封止部の少なくとも一部に触媒物質が担持されているフィルタ、ＳＣＲ触媒の組合せにより構成される排気ガス浄化装置の圧力損失が低減できる理由は、以下のように考えられる。
一般に排気ガス浄化装置に用いられるセラミックハニカム構造体の圧力損失は、（１）排気ガス流路の流入口及び流出口で排気ガスが圧縮或いは膨張することにより生じる圧力損失、（２）排気ガス流路内での流路抵抗による圧力損失の合計で表される。セラミックハニカムフィルタでは、上記に更に（３）隔壁を排気ガスが通過する際の圧力損失が加算される。このため、従来技術の酸化触媒が担持されたハニカム構造体、セラミックハニカムフィルタ、ＳＣＲ触媒が担持されたハニカム構造体から構成される排ガス装置を本発明のように少なくとも一つの排気ガス流入側目封止部が排気ガス流入側端面より離れて配置されていると共に、隔壁及び／または目封止部の少なくとも一部に触媒物質が担持されているセラミックハニカムフィルタ及びＳＣＲ触媒が担持されたハニカム構造体から構成される排気ガス浄化装置とすることにより、従来技術の酸化触媒での排気ガス流路流入側及び流出口の圧力損失及び流路抵抗による圧力損失が発生しなくなるため、排気ガス浄化装置全体の圧力損失を低減することが可能となる。また、図１に示す本発明の排気ガス浄化装置では、排気ガス通路２の長さ自体を、図４に示す従来の排気ガス浄化装置に比べて短縮することができるため、排気ガス浄化装置の全体の圧力損失を小さくすることができ、且つ排気ガス浄化装置を小型化することができる。 Further, as described above, at least one exhaust gas inflow side of the present invention as compared with the exhaust gas purification device constituted by the combination of the oxidation catalyst, the filter, the reducing agent supply source, and the SCR catalyst device, which is a conventional technique Exhaust gas composed of a combination of a filter and an SCR catalyst in which the plugging portion is arranged away from the end face on the exhaust gas inflow side and the catalytic material is supported on at least a part of the partition wall and / or the plugging portion. The reason why the pressure loss of the gas purification device can be reduced is considered as follows.
In general, the pressure loss of a ceramic honeycomb structure used in an exhaust gas purification device is as follows: (1) Pressure loss caused by compression or expansion of exhaust gas at the inlet and outlet of the exhaust gas flow path; (2) Exhaust gas flow It is expressed as the total pressure loss due to flow path resistance in the channel. In the ceramic honeycomb filter, (3) pressure loss when exhaust gas passes through the partition walls is further added to the above. Therefore, at least one exhaust gas inflow side plugging as in the present invention is made of an exhaust gas apparatus composed of a honeycomb structure supporting a conventional oxidation catalyst, a ceramic honeycomb filter, and a honeycomb structure supporting an SCR catalyst. A honeycomb structure in which a stop portion is disposed away from an end surface on the exhaust gas inflow side and a catalytic substance is supported on at least a part of partition walls and / or plugging portions and a honeycomb structure on which an SCR catalyst is supported The exhaust gas purifying device comprising the exhaust gas purifying device as described above is free from pressure loss due to pressure loss at the inflow side and the outlet side of the exhaust gas flow channel and the flow channel resistance in the prior art oxidation catalyst. It is possible to reduce the pressure loss. Further, in the exhaust gas purification apparatus of the present invention shown in FIG. 1, the length of the exhaust gas passage 2 itself can be shortened as compared with the conventional exhaust gas purification apparatus shown in FIG. The overall pressure loss can be reduced, and the exhaust gas purification device can be reduced in size.

本発明の排気ガス浄化方法は、ディーゼルエンジンから排出される窒素酸化物及び粒子状物質を含有する排気ガスを浄化する装置に配設されたセラミックハニカムフィルタの少なくとも一つの排気ガス流入側目封止部が排気ガス流入側端面より離れて配置されていると共に、隔壁及び／または目封止部の少なくとも一部に触媒物質が担持され、前記排気ガス中の粒子状物質を前記セラミックハニカムフィルタ内で燃焼させ、前記フィルタの排気ガス排出側に配設されたＳＣＲ触媒中に導入する排気ガス中のＮＯ／ＮＯ２のモル比を１／２〜２／１にすることを特徴としている。このため、ＳＣＲ触媒上におけるＮＯ及びＮＯ２等のＮＯxからＮ２への転化率が増加し、ＮＯxの浄化効率が改善される効果も有している。これは、少なくとも一つの排気ガス流入側目封止部が排気ガス流入側端面より離れて配置されていると共に、隔壁及び／または目封止部の少なくとも一部に触媒物質が担持されているセラミックハニカムフィルタにおいて、担持された触媒物質の触媒作用により、粒子状物質の燃焼が行われることから、フィルタから排出される粒子状物質が燃焼浄化された後の排気ガス中に、ＮＯ及びＮＯ２が含まれ、且つこのＮＯ及びＮＯ２のモル比をＮＯ／ＮＯ２で１／２〜２／１とした排気ガスが得られ易くなり、これに、窒素系還元剤であるアンモニアまたは、尿素を添加してガス混合物を形成し、このガス混合物がＳＣＲ触媒上に導入されると、ＮＯxからＮ２への転化率が増加し、排気ガス浄化装置でのＮＯxの浄化効率が改善されるためである。 The exhaust gas purification method of the present invention includes plugging at least one exhaust gas on the exhaust gas inlet side of a ceramic honeycomb filter disposed in a device for purifying exhaust gas containing nitrogen oxides and particulate matter discharged from a diesel engine. And the catalyst material is supported on at least a part of the partition wall and / or the plugging portion, and the particulate matter in the exhaust gas is contained in the ceramic honeycomb filter. It is characterized in that the NO / NO 2 molar ratio in the exhaust gas introduced into the SCR catalyst disposed on the exhaust gas discharge side of the filter is set to 1/2 to 2/1. Therefore, conversion to N 2 is increased from NO and NO 2 or the like of the NO x in the SCR catalyst, the effect also has the purification efficiency of the NO x can be improved. This is because a ceramic in which at least one exhaust gas inflow side plugging portion is arranged away from the exhaust gas inflow side end face and a catalytic substance is supported on at least a part of the partition wall and / or the plugging portion. In the honeycomb filter, the particulate matter is combusted by the catalytic action of the supported catalyst material. Therefore, NO and NO 2 are contained in the exhaust gas after the particulate matter discharged from the filter is burnt and purified. It included, and the molar ratio of NO and NO 2 in the NO / NO 2 1 / 2~2 / 1 and the exhaust gas is easily obtained that, to this, ammonia or a nitrogen-based reducing agent, adding urea When a gas mixture is formed and this gas mixture is introduced onto the SCR catalyst, the conversion rate from NO x to N 2 increases, and the NO x purification efficiency in the exhaust gas purification device is improved. so That.

従来技術の排気ガス浄化装置では、酸化触媒、フィルタ、還元剤の供給源、ＳＣＲ触媒をこの順序で配置して、酸化触媒が排気ガスの温度を上昇させると共に、ＮＯxをＮＯ２に転化させ、酸化触媒の後に配置されたフィルタが粒子状物質をＮＯ２を用いて燃焼させ、更にＳＣＲ触媒においてＮＯxを浄化していたのに対し、本発明の排気ガス浄化装置及び排気ガス浄化方法によれば、フィルタ１１で排気ガス中の粒子状物質を効率的に燃焼させると共に、排気ガス中のＮＯ／ＮＯ２比を適切に調整させて、このフィルタから排出された排気ガスを、ＳＣＲ触媒においてＮＯxを効率的に低減できるため、従来技術の排気ガス浄化装置に比べて排気ガス浄化装置全体の圧力損失を低減できるのと共に浄化性能を高めることが可能となる。 In the prior art exhaust gas purification device, an oxidation catalyst, a filter, a reducing agent supply source, and an SCR catalyst are arranged in this order so that the oxidation catalyst raises the temperature of the exhaust gas and converts NO x into NO 2. The filter disposed after the oxidation catalyst combusts the particulate matter using NO 2 and further purifies NO x in the SCR catalyst, whereas the exhaust gas purification device and the exhaust gas purification method of the present invention According to the present invention, the particulate matter in the exhaust gas is efficiently burned by the filter 11 and the NO / NO 2 ratio in the exhaust gas is appropriately adjusted so that the exhaust gas discharged from the filter is passed through the SCR catalyst. Since NO x can be efficiently reduced, the pressure loss of the entire exhaust gas purification device can be reduced and the purification performance can be improved as compared with the exhaust gas purification device of the prior art.

本発明の排気ガス浄化装置に配設されるセラミックハニカムフィルタの排気ガス流入側目封止部端面が、セラミックハニカムフィルタの流入側端面から該セラミックハニカムフィルタ全長の０．７倍以下の長さの区間に配置されていることが好ましいのは、流入側端面１２から該セラミックハニカムフィルタ全長の０．７倍の長さの区間を越えて配置すると、セラミックハニカムフィルタの全体の長さには制約があるため、排気ガス流入側目封止部より流出側の隔壁３２の面積が、隔壁３１に比べて少なくなるため、ハニカムフィルタ全体の圧力損失が上昇することもあるからである。また、更に好ましい流入側目封止部端面５１の配置区間は、セラミックハニカムフィルタ流入側端面１２から該セラミックハニカムフィルタ全長の０．１〜０．４倍の長さの区間である。   The exhaust gas inflow side plugging portion end face of the ceramic honeycomb filter disposed in the exhaust gas purification apparatus of the present invention has a length of 0.7 times or less of the entire length of the ceramic honeycomb filter from the inflow side end face of the ceramic honeycomb filter. It is preferable that the ceramic honeycomb filter is disposed in the section. If the section is disposed beyond the section of 0.7 times the total length of the ceramic honeycomb filter from the inflow side end face 12, the entire length of the ceramic honeycomb filter is restricted. For this reason, the area of the partition wall 32 on the outlet side from the plugging portion on the exhaust gas inflow side is smaller than that of the partition wall 31, and the pressure loss of the entire honeycomb filter may increase. Further, a more preferable arrangement section of the inflow side plugging end face 51 is a section having a length of 0.1 to 0.4 times the entire length of the ceramic honeycomb filter from the end face 12 of the ceramic honeycomb filter inflow side.

次に、本発明の排気ガス浄化装置に配設されるセラミックハニカムフィルタに担持される触媒物質が、白金族金属を含んでなることが好ましいのは、白金族金属を含む触媒物質が、主に排気ガスの酸化反応を促進し、排気ガスの温度を上昇させることから、フィルタ内部温度を前記触媒物質の活性下限温度以上に維持することがより確実にできるからである。このため、排ガス中の粒子状物質を効率よく燃焼させることができ、特に流入側目封止部での未燃焼粒子状物質の堆積による圧力損失の上昇を防ぐことが出来る。尚、白金族金属を含む触媒物質は、たとえば、Ｐｔ、Ｐｄ、Ｒｕ、Ｒｈ又はその組合せ、白金族金属酸化物等が含まれるが、アルカリ土類金属酸化物や希土類酸化物等を含んでも良い。また、白金族金属を含む触媒物質には、公知のγアルミナ等の活性アルミナからなる高比表面積材料が含まれると、白金族金属等と排気ガスとの接触面積を大きくすることができ、排気ガスの浄化効率を高めることができることから好ましい。   Next, the catalyst material supported on the ceramic honeycomb filter disposed in the exhaust gas purification apparatus of the present invention preferably contains a platinum group metal. The catalyst material containing a platinum group metal mainly This is because the oxidation reaction of the exhaust gas is promoted and the temperature of the exhaust gas is increased, so that the internal temperature of the filter can be more reliably maintained at the activation lower limit temperature or higher. For this reason, the particulate matter in the exhaust gas can be burned efficiently, and an increase in pressure loss due to the accumulation of unburned particulate matter at the inflow side plugged portion can be prevented. The catalyst material containing a platinum group metal includes, for example, Pt, Pd, Ru, Rh or a combination thereof, a platinum group metal oxide, and the like, but may include an alkaline earth metal oxide, a rare earth oxide, and the like. . Further, if the catalyst material containing platinum group metal contains a high specific surface area material made of active alumina such as known γ alumina, the contact area between the platinum group metal etc. and the exhaust gas can be increased, This is preferable because the gas purification efficiency can be increased.

また、本発明の排気ガス浄化装置に配設されるセラミックハニカムフィルタの排気ガス流入側の隔壁に担持された触媒物質の活性度が、排気ガス流出側の隔壁に担持された触媒物質の活性度に比べて高いことが好ましいのは、流入側目封止部５０より流入側に配置された隔壁３１に担持された触媒物質上で、排気ガスの触媒反応が促進され、その反応熱を多くすることができ、フィルタ内部温度を前記触媒物質の活性下限温度以上に維持することがより確実にできるからである。このため、排ガス中の粒子状物質を効率よく燃焼させることができ、特に流入側目封止部での未燃焼粒子状物質の堆積による圧力損失の上昇を防ぐことが出来る。ここで、排気ガス流入側の隔壁に担持された触媒物質の活性度が、排気ガス流出側の隔壁に担持された触媒物質の活性度に比べて高いというのは、例えば流入側目封止部より排気ガス流入側である隔壁に担持された触媒物質中の白金族金属を含む触媒物質の含有量や、助触媒物質であるアルカリ土類金属酸化物、希土類酸化物、或いはベース金属触媒の含有量を、排気ガス流出側の隔壁に担持された触媒物質に比べて多く担持させ、担持された触媒全体として見た時に、触媒の性能が高いことを意味する。
例えば、本発明の排気ガス浄化装置において、セラミックハニカムフィルタの流入側目封止部より排気ガス流入側の隔壁に担持された触媒物質中の白金族金属含有量を、排気ガス流出側の隔壁に担持された触媒物質中の白金族金属含有量よりも多くすることにより、長期に亘り圧力損失の上昇を防ぐことができる。 In addition, the activity of the catalyst material supported on the partition wall on the exhaust gas inflow side of the ceramic honeycomb filter disposed in the exhaust gas purification apparatus of the present invention is the activity of the catalyst material supported on the partition wall on the exhaust gas outflow side. It is preferable that the exhaust gas catalytic reaction of the exhaust gas is promoted on the catalytic material carried on the partition wall 31 arranged on the inflow side from the inflow side plugging portion 50 and the reaction heat is increased. This is because it is possible to more reliably maintain the internal temperature of the filter at the activation lower limit temperature or more of the catalyst substance. For this reason, the particulate matter in the exhaust gas can be burned efficiently, and an increase in pressure loss due to the accumulation of unburned particulate matter at the inflow side plugged portion can be prevented. Here, the activity of the catalyst material supported on the partition wall on the exhaust gas inflow side is higher than the activity of the catalyst material supported on the partition wall on the exhaust gas outflow side. The content of the catalytic material containing platinum group metal in the catalytic material supported on the partition wall on the exhaust gas inflow side, the inclusion of alkaline earth metal oxide, rare earth oxide, or base metal catalyst as the promoter material This means that the catalyst performance is high when the catalyst is supported in a larger amount than the catalyst material supported on the partition wall on the exhaust gas outflow side and viewed as the entire supported catalyst.
For example, in the exhaust gas purification apparatus of the present invention, the platinum group metal content in the catalyst material supported on the partition wall on the exhaust gas inflow side from the inflow side plugging portion of the ceramic honeycomb filter is stored in the partition wall on the exhaust gas outflow side. By increasing the content of the platinum group metal in the supported catalyst material, it is possible to prevent an increase in pressure loss over a long period of time.

また、本発明の排気ガス浄化装置に配設されるセラミックハニカムフィルタの流入側目封止部５０より排気ガス流入側である隔壁には、酸化触媒である、Ｐｔ、Ｐｄ、Ｒｕ、Ｒｈ等の白金族金属を含む触媒物質の含有量を多く担持し、排気ガス流出側の隔壁３２には、助触媒であるベース金属触媒、典型的には酸化ランタン、酸化セシウム、酸化バナジウム類よりなる触媒物質及び白金族金属を含む触媒物質を多く担持させることにより、微粒子の燃焼が効率よく行われるため、長期に亘り圧力損失の上昇を防ぐことができる。   In addition, the partition on the exhaust gas inflow side from the inflow side plugging portion 50 of the ceramic honeycomb filter disposed in the exhaust gas purification device of the present invention has an oxidation catalyst such as Pt, Pd, Ru, Rh, etc. A large amount of catalyst material containing a platinum group metal is supported, and the partition wall 32 on the exhaust gas outflow side has a base metal catalyst as a promoter, typically a catalyst material made of lanthanum oxide, cesium oxide, or vanadium oxides. Since a large amount of catalyst material containing platinum group metal is supported, fine particles are burned efficiently, so that an increase in pressure loss can be prevented over a long period of time.

また、本発明の排気ガス浄化装置は、多孔質セラミックハニカム構造体の所望の流路を目封止したセラミックハニカムフィルタの、少なくとも一つの排気ガス流入側目封止部が排気ガス流入側端面より離れて配置されていると共に、隔壁及び／または目封止部の少なくとも一部に触媒物質が担持されているフィルタと、窒素酸化物（ＮＯｘ）を浄化させるＳＣＲ触媒を、この順序で配置して、ディーゼルエンジンから排出されるＮＯｘ及び粒子状物質を浄化しているが、ＳＣＲ触媒の上流には還元剤の供給源を設けて、還元剤を排気ガスに添加した後、この排気ガスをＳＣＲ触媒に供給する。また、ＳＣＲ触媒の下流に、未反応のまま或いは複生成物としてアンモニアが発生する場合は、ＳＣＲ触媒の下流側にアンモニアの浄化触媒を配置しても良い。 In the exhaust gas purifying apparatus of the present invention, at least one exhaust gas inflow side plugged portion of the ceramic honeycomb filter in which a desired flow path of the porous ceramic honeycomb structure is plugged from the end surface of the exhaust gas inflow side. A filter which is arranged apart from each other and in which a catalytic substance is supported on at least a part of the partition walls and / or plugging portions and an SCR catalyst which purifies nitrogen oxide (NO x ) are arranged in this order. Te, although purifies NO x and particulate matter discharged from a diesel engine, upstream of the SCR catalyst is provided a source of reducing agent, after the addition of the reducing agent to the exhaust gas, the exhaust gas Supply to SCR catalyst. Further, when ammonia is generated unreacted or as a double product downstream of the SCR catalyst, an ammonia purification catalyst may be disposed on the downstream side of the SCR catalyst.

本発明の排気ガス浄化装置に備えられるハニカム構造のフィルタは、隔壁の気孔率が、５０％〜８０％、隔壁の平均細孔径が１０〜４０μmであると好ましい。ハニカムフィルタの隔壁の気孔率が５０％未満であると、隔壁を排気ガスが通過する際の通気抵抗が大きくなるため、フィルタの圧力損失が大きくなり、排気ガス浄化装置全体の圧力損失も大きくなるからである。一方、気孔率が８０％を超えると、フィルタの強度が低下し、排気ガス浄化用装置として使用された際の、機械的応力や振動により破損するおそれがあるからである。ハニカムフィルタの気孔率は、好ましくは、６０〜７５％である。   The honeycomb structure filter provided in the exhaust gas purification apparatus of the present invention preferably has a partition wall porosity of 50% to 80% and an average partition wall pore size of 10 to 40 μm. When the porosity of the partition walls of the honeycomb filter is less than 50%, the ventilation resistance when the exhaust gas passes through the partition walls increases, so the pressure loss of the filter increases and the pressure loss of the entire exhaust gas purification device also increases. Because. On the other hand, if the porosity exceeds 80%, the strength of the filter is lowered, and there is a risk of damage due to mechanical stress or vibration when used as an exhaust gas purification device. The porosity of the honeycomb filter is preferably 60 to 75%.

ハニカムフィルタの隔壁の平均細孔径が１０μｍ未満であると、隔壁を排気ガスが通過する際の通気抵抗が大きくなるため、フィルタの圧力損失が大きくなり、排気ガス浄化装置全体の圧力損失も大きくなるからである。一方、平均細孔径が４０μｍを超えると、フィルタの強度が低下し、排気ガス浄化用装置として使用された際の、機械的応力や振動により破損するおそれがあるからである。尚、ハニカムフィルタの平均細孔径のより好ましい範囲は、１５〜２５μｍである。   If the average pore diameter of the partition walls of the honeycomb filter is less than 10 μm, the ventilation resistance when exhaust gas passes through the partition walls increases, so the pressure loss of the filter increases and the pressure loss of the exhaust gas purification device as a whole also increases. Because. On the other hand, if the average pore diameter exceeds 40 μm, the strength of the filter is lowered, and there is a risk of damage due to mechanical stress or vibration when used as an exhaust gas purification device. A more preferable range of the average pore diameter of the honeycomb filter is 15 to 25 μm.

本発明の排気ガス浄化装置に備えられる、ハニカムフィルタの隔壁厚は、０．１〜０．５ｍｍが好ましく、隔壁のピッチは１．２ｍｍ以上が好ましい。隔壁厚が０．１ｍｍ未満では、ハニカムフィルタの強度が低下し、好ましくない。一方、隔壁厚が０．５ｍｍを超えると、排気ガスに対する隔壁の通気抵抗が大きくなるため、ハニカムフィルタの圧力損失が大きくなるからである。より好ましい隔壁厚さは、０．２〜０．４ｍｍである。また、隔壁のピッチが１．２ｍｍ未満であると、ハニカムフィルタの入口の開口面積が小さくなることから、ハニカムフィルタ入口の圧力損失が大きくなるためである。   The partition wall thickness of the honeycomb filter provided in the exhaust gas purification apparatus of the present invention is preferably 0.1 to 0.5 mm, and the partition wall pitch is preferably 1.2 mm or more. When the partition wall thickness is less than 0.1 mm, the strength of the honeycomb filter decreases, which is not preferable. On the other hand, when the partition wall thickness exceeds 0.5 mm, the ventilation resistance of the partition wall to the exhaust gas increases, so that the pressure loss of the honeycomb filter increases. A more preferable partition wall thickness is 0.2 to 0.4 mm. Further, when the partition wall pitch is less than 1.2 mm, the opening area of the inlet of the honeycomb filter becomes small, and the pressure loss at the inlet of the honeycomb filter becomes large.

上記、排気ガス浄化装置に備えられるハニカムフィルタの隔壁を構成する材料としては、本発明が主にディーゼルエンジンの排気ガスを浄化するために使用されるため、耐熱性に優れた材料を使用することが好ましく、コージェライト、アルミナ、ムライト、窒化珪素、炭化珪素及びＬＡＳからなる群から選ばれた少なくとも１種を主結晶とするセラミック材料を用いることが好ましい。中でも、コージェライトを主結晶とするハニカム構造体は、安価で耐熱性、耐食性に優れ、また低熱膨張であることから最も好ましい。   As the material constituting the partition wall of the honeycomb filter provided in the exhaust gas purification device, since the present invention is mainly used for purifying exhaust gas of a diesel engine, a material having excellent heat resistance should be used. It is preferable to use a ceramic material whose main crystal is at least one selected from the group consisting of cordierite, alumina, mullite, silicon nitride, silicon carbide and LAS. Among these, a honeycomb structure having cordierite as a main crystal is most preferable because it is inexpensive, excellent in heat resistance and corrosion resistance, and has low thermal expansion.

次に本発明の排気ガス浄化装置に使用される、多孔質セラミックハニカム構造体の所望の流路を目封止したセラミックハニカムフィルタの、少なくとも一つの排気ガス流入側目封止部が排気ガス流入側端面より離れて配置されているセラミックハニカムフィルタ１１の目封止部の形成方法の一例を図３を用いて説明する。ハニカム構造体の排気ガス流入側端面に図３に示すように市松模様に樹脂製スラリー導入通路８１を設けた樹脂製のマスク８０を装着し、図３のＡ部拡大図の矢印で示すようにスラリー導入通路８１を通してスラリー状の目封止材５３を導入し、ハニカム構造体の流路の一部に充填する。その後、スラリー状の目封止材５３中に含まれる水分はハニカム構造体の隔壁に吸水され目封止材が隔壁に着肉して行き保形性が得られるようになると、固化していないスラリーを排出し、樹脂製マスクを除去後、固化した目封止材の乾燥を行う。このとき樹脂製スラリー導入通路８１内に存在するスラリー状の目封止材は隔壁からの吸水が無いことから固化しないため、スラリ−導入通路の長さを調整することにより、排気ガス流入側目封止部のハニカム構造体流入側端面からの形成位置を決定することができる。一方、流出側の端面は、端部に目封止部を形成し、その後、目封止材の焼成を行い、隔壁と目封止材を一体化せしめる。   Next, at least one exhaust gas inflow side plugged portion of the ceramic honeycomb filter used in the exhaust gas purifying apparatus of the present invention plugged with a desired flow path of the porous ceramic honeycomb structure is exhaust gas inflow An example of a method for forming a plugged portion of the ceramic honeycomb filter 11 arranged away from the side end face will be described with reference to FIG. A resin mask 80 having a resin slurry introduction passage 81 provided in a checkered pattern is attached to the exhaust gas inflow side end face of the honeycomb structure as shown in FIG. The slurry-like plugging material 53 is introduced through the slurry introduction passage 81 and filled in a part of the flow path of the honeycomb structure. After that, the water contained in the slurry-like plugging material 53 is absorbed into the partition walls of the honeycomb structure, and the plugging material is deposited on the partition walls to obtain the shape retention. After discharging the slurry and removing the resin mask, the solidified plugging material is dried. At this time, the slurry-like plugging material present in the resin slurry introduction passage 81 does not solidify because there is no water absorption from the partition wall. Therefore, by adjusting the length of the slurry introduction passage, the exhaust gas inflow side opening can be adjusted. The formation position of the sealing portion from the end face on the inflow side of the honeycomb structure can be determined. On the other hand, the end face on the outflow side forms a plugging portion at the end, and then the plugging material is fired to integrate the partition wall and the plugging material.

なお、その他の方法としては、注射針状の管をハニカム構造体の端部から流路の所定位置まで挿入し、この管を通して所定位置に所定量のペースト状の目封止材を導入後、乾燥、焼成させる方法や、セラミックチップをハニカム構造体の内部に埋め込み、焼成させる方法等を採用することができる。
更には、両端が目封止された従来構造のセラミックハニカムフィルタの排気ガス流入側端面に目封止が施されていないセラミックハニカム構造体を配置させ、両者を一体化せしめることにより、製造することも可能である。 As another method, after inserting a needle-like tube from the end of the honeycomb structure to a predetermined position of the flow path, and introducing a predetermined amount of paste-like plugging material into the predetermined position through this tube, A method of drying and firing, a method of embedding ceramic chips in the honeycomb structure and firing, etc. can be employed.
Furthermore, a ceramic honeycomb structure that is not plugged is disposed on the exhaust gas inflow side end face of a ceramic honeycomb filter having a conventional structure that is plugged at both ends, and the two are integrated to manufacture the filter. Is also possible.

本発明の排気ガス浄化装置に備えられるＳＣＲ触媒は、外周壁と外周壁の内側で軸方向に多孔質隔壁により仕切られた多数の流通孔を有するセラミックハニカム構造体の隔壁表面にＳＣＲ触媒物質を担持して形成されると良い。特に、本発明の排気ガス浄化装置は、
多孔質セラミックハニカム構造体の所望の流路を目封止したセラミックハニカムフィルタの、少なくとも一つの排気ガス流入側目封止部が排気ガス流入側端面より離れて配置されていると共に、隔壁及び／または目封止部の少なくとも一部に触媒物質が担持されているフィルタとＳＣＲ触媒とが、この順序で配置されており、セラミックハニカムフィルタで粒子状物質を効率的に燃焼させ、更にこのフィルタから排出された排気ガスを、ＳＣＲ触媒においてＮＯxを効率的に低減させているため、ＳＣＲ触媒に用いられる、セラミックハニカム構造体の幾何学的表面積は大きい方が好ましい。このため、ハニカム構造体の隔壁厚は、０．０５〜０．２５ｍｍが好ましく、隔壁のピッチは０．８〜１．６ｍｍが好ましい。隔壁厚が０．０５ｍｍ未満では、ハニカムフィルタの強度が低下し、好ましくなく、隔壁厚が０．２５ｍｍを超えると、排気ガスに対する通気抵抗が大きくなるため、ハニカム構造体の圧力損失が大きくなるからである。より好ましい隔壁厚さは、０．０８〜０．１５ｍｍである。また、隔壁のピッチが０．８ｍｍ未満であると、ハニカム構造体の入口の開口面積が小さくなることから、ハニカム構造体の圧力損失が大きくなるためであり、隔壁のピッチが１．６ｍｍを越えると、幾何学的表面積が小さくなり、ＳＣＲ触媒の浄化性能が低下するためである。より好ましい隔壁のピッチは、０．９〜１．３ｍｍである。 The SCR catalyst provided in the exhaust gas purifying apparatus of the present invention has an SCR catalyst material on the partition wall surface of a ceramic honeycomb structure having a plurality of flow holes axially partitioned by a porous partition wall inside the outer peripheral wall and the outer peripheral wall. It is good to form by carrying. In particular, the exhaust gas purification device of the present invention is
At least one exhaust gas inflow side plugging portion of the ceramic honeycomb filter plugged in a desired flow path of the porous ceramic honeycomb structure is disposed away from the end surface of the exhaust gas inflow side, and the partition wall and / or Alternatively, the filter and the SCR catalyst in which the catalyst material is supported on at least a part of the plugged portion are arranged in this order, and the particulate matter is efficiently burned by the ceramic honeycomb filter. the exhaust gas discharged, since the effectively reduce NO x in the SCR catalyst, used in the SCR catalyst, the geometric surface area of the ceramic honeycomb structure is larger is preferable. For this reason, the partition wall thickness of the honeycomb structure is preferably 0.05 to 0.25 mm, and the partition wall pitch is preferably 0.8 to 1.6 mm. When the partition wall thickness is less than 0.05 mm, the strength of the honeycomb filter decreases, which is not preferable. When the partition wall thickness exceeds 0.25 mm, the ventilation resistance to the exhaust gas increases, so the pressure loss of the honeycomb structure increases. It is. A more preferable partition wall thickness is 0.08 to 0.15 mm. In addition, if the partition wall pitch is less than 0.8 mm, the opening area at the inlet of the honeycomb structure becomes small, and thus the pressure loss of the honeycomb structure increases, and the partition wall pitch exceeds 1.6 mm. This is because the geometric surface area is reduced and the purification performance of the SCR catalyst is lowered. A more preferable partition pitch is 0.9 to 1.3 mm.

また、本発明の排気ガス浄化装置に備えられるＳＣＲ触媒に用いられるセラミックハニカム構造体が、上記のような隔壁厚さ、隔壁ピッチを有している場合には、ハニカム構造体の隔壁の気孔率は、２５％〜４５％、隔壁の平均細孔径は、１〜１０μmであると好ましい。ハニカム構造体の隔壁の気孔率が２５％未満であると、ＳＣＲ触媒物質が担持しにくくなり、浄化性能が低下する場合があるからであり、気孔率が４５％を超えると、隔壁の厚さが０．０５〜０．２５ｍｍと薄いため、ハニカム構造体の強度が低下し、排気ガス浄化用装置として使用された際の、機械的応力や振動により破損するおそれがあるからである。   Further, when the ceramic honeycomb structure used for the SCR catalyst provided in the exhaust gas purification apparatus of the present invention has the partition wall thickness and partition wall pitch as described above, the porosity of the partition walls of the honeycomb structure is as follows. Is preferably 25% to 45%, and the average pore diameter of the partition walls is preferably 1 to 10 μm. This is because when the porosity of the partition walls of the honeycomb structure is less than 25%, the SCR catalyst substance is hardly supported and the purification performance may be deteriorated. When the porosity exceeds 45%, the thickness of the partition walls This is because the strength of the honeycomb structure is lowered and may be damaged due to mechanical stress or vibration when used as an exhaust gas purification device.

また、本発明の排気ガス浄化装置に備えられるＳＣＲ触媒に用いられるセラミックハニカム構造体の平均細孔径が１μｍ未満であると、ＳＣＲ触媒物質が担持しにくくなり、浄化性能が低下する場合があるからであり、平均細孔径が１０μｍを超えると、隔壁の厚さが０．０５〜０．２５ｍｍと薄いため、ハニカム構造体の強度が低下し、排気ガス浄化用装置として使用された際の、機械的応力や振動により破損するおそれがあるからである。   Further, when the average pore diameter of the ceramic honeycomb structure used for the SCR catalyst provided in the exhaust gas purification apparatus of the present invention is less than 1 μm, the SCR catalyst substance is hardly supported and the purification performance may be deteriorated. When the average pore diameter exceeds 10 μm, the partition wall thickness is as thin as 0.05 to 0.25 mm, so that the strength of the honeycomb structure is lowered and the machine is used as an exhaust gas purification device. This is because it may be damaged by mechanical stress or vibration.

本発明の排気ガス浄化装置に備えられるＳＣＲ触媒に用いられるセラミックハニカム構造体の隔壁を構成する材料としては、本発明が主にディーゼルエンジンの排気ガスを浄化するために使用されるため、耐熱性に優れた材料を使用することが好ましく、コージェライト、アルミナ、ムライト、窒化珪素、炭化珪素及びＬＡＳからなる群から選ばれた少なくとも１種を主結晶とするセラミック材料を用いることが好ましい。中でも、コージェライトを主結晶とするハニカム構造体は、安価で耐熱性、耐食性に優れ、また低熱膨張であることから最も好ましい。   As a material constituting the partition walls of the ceramic honeycomb structure used for the SCR catalyst provided in the exhaust gas purification apparatus of the present invention, the present invention is mainly used for purifying exhaust gas of a diesel engine. It is preferable to use a ceramic material having at least one main crystal selected from the group consisting of cordierite, alumina, mullite, silicon nitride, silicon carbide and LAS. Among these, a honeycomb structure having cordierite as a main crystal is most preferable because it is inexpensive, excellent in heat resistance and corrosion resistance, and has low thermal expansion.

本発明の排気ガス浄化装置に備えられるＳＣＲ触媒に用いられる触媒物質としては、Ｖ２Ｏ５、ＷＯ３、ＴｉＯ２が好適であり、これらに加えてＰｔ、Ｆｅ２Ｏ３、ＣｕＯ、Ｍｎ２Ｏ３、Ｃｒ２Ｏ３、ＭｏＯ３等を用いてもよい。 V 2 O 5 , WO 3 , TiO 2 are suitable as the catalyst material used for the SCR catalyst provided in the exhaust gas purification apparatus of the present invention. In addition to these, Pt, Fe 2 O 3 , CuO, Mn 2 O 3 , Cr 2 O 3 , MoO 3 or the like may be used.

以上の説明のように、本発明の排気ガス浄化装置によれば、排気ガス中の粒子状物資及びＮＯxの有害成分を効果的に低減でき、且つ排気ガス浄化装置に必要な部品数を減らすことができる。また、圧力損失の原因になる部品数が少ないため、排気ガス浄化装置全体としての圧力損失を低減できるという大きな効果と、従来技術の排気ガス浄化装置に比べ小型化が可能となる。 As described above, according to the exhaust gas purification apparatus of the present invention, particulate matter and NO x harmful components in the exhaust gas can be effectively reduced, and the number of parts required for the exhaust gas purification apparatus is reduced. be able to. In addition, since the number of components that cause pressure loss is small, it is possible to reduce the pressure loss of the exhaust gas purification device as a whole, and it is possible to reduce the size as compared with the exhaust gas purification device of the prior art.

（実施例）
本発明に係わるディーゼルエンジンの排気ガス浄化装置の実施の形態の排気ガス浄化装置における、フィルター１１の製造方法について、模式断面図の図３を用いて説明する。
カオリン、タルク、シリカ、水酸化アルミ、アルミナなどのコージェライト生成原料粉末に、成形助剤と造孔剤を添加し、規定量の水を注入して更に十分な混合を行い、ハニカム構造に押出成形可能な坏土を調整した。そして、公知の押出成形用金型を用い押出成形し、外周壁と、この外周壁の内周側で隔壁により囲まれた断面が四角形状の流路を有するハニカム構造の成形体を作製し、乾燥後焼成を行い、直径２６７ｍｍ、全長Ｌ３０５ｍｍ、隔壁のピッチ１．５０ｍｍで、隔壁厚さ０．３ｍｍの隔壁構造を有し、隔壁の気孔率が６５％、平均細孔径が２０μｍのセラミックハニカム構造体１０を作製した。 (Example)
A method for manufacturing the filter 11 in the exhaust gas purification apparatus according to the embodiment of the exhaust gas purification apparatus for a diesel engine according to the present invention will be described with reference to FIG.
Add a molding aid and a pore-forming agent to a cordierite-forming raw material powder such as kaolin, talc, silica, aluminum hydroxide, alumina, etc., inject a specified amount of water, mix thoroughly, and extrude into a honeycomb structure. The moldable clay was adjusted. Then, extrusion molding using a known extrusion mold, to produce a honeycomb structure molded body having a square-shaped passage surrounded by a partition wall on the outer peripheral wall and the inner peripheral side of the outer peripheral wall, A ceramic honeycomb structure having a partition wall structure with a diameter of 267 mm, a total length of L305 mm, a partition wall pitch of 1.50 mm, a partition wall thickness of 0.3 mm, a partition wall porosity of 65%, and an average pore diameter of 20 μm is fired after drying. A body 10 was produced.

次に、図３に示すようにハニカム構造体の排気ガス流入側端面に市松模様にスラリー導入通路８１を設けた樹脂製のマスク８０を装着し、スラリー導入通路を通してスラリー状の目封止材を導入、ハニカム構造体の流路の一部に充填した。その後、目封止材が隔壁に着肉して、保形性が得られた後、樹脂製マスクを除去し、目封止材５３の乾燥を行った。一方、ハニカム構造体の排気ガス流出側端面の目封止部は、端面にマスキングフィルムを接着剤で貼り付けた後、市松模様となるように穿孔し、続いて、スラリー状の目封止材を端面より導入して目封止部を形成した。次いで、バッチ式焼成炉を用いて温度制御しつつ目封止材の焼成を行い、ハニカムフィルタ１１を得た。この時の、排気ガス流入側目封止部の排気ガス流入側端面５１とハニカムフィルタ端面１２の間の距離Ｘは１００ｍｍとなるようにした。   Next, as shown in FIG. 3, a mask 80 made of resin having a slurry introduction passage 81 provided in a checkered pattern on the exhaust gas inflow side end face of the honeycomb structure is attached, and a slurry-like plugging material is passed through the slurry introduction passage. Introduced, a part of the flow path of the honeycomb structure was filled. Then, after the plugging material was attached to the partition walls and shape retention was obtained, the resin mask was removed and the plugging material 53 was dried. On the other hand, the plugging portion on the exhaust gas outflow side end face of the honeycomb structure has a masking film attached to the end face with an adhesive and then perforated so as to have a checkered pattern, followed by a slurry-like plugging material. Was introduced from the end face to form a plugged portion. Next, the plugging material was fired while controlling the temperature using a batch-type firing furnace, whereby a honeycomb filter 11 was obtained. At this time, the distance X between the exhaust gas inflow side end surface 51 of the exhaust gas inflow side plugging portion and the honeycomb filter end surface 12 was set to 100 mm.

前記のハニカムフィルタに対して、白金（Ｐｔ）、酸化セリウム、及び活性アルミナからなる触媒物質を隔壁表面及び隔壁中の細孔内部、更には目封止部表面及び目封止部中の細孔内部に担持させた。担持量はＰｔ量で２ｇ／Ｌ（ハニカムフィルタ容積１Ｌに対して２ｇ担持の意味）とした。
上記のように作成したフィルタ１１を、図２に示すように、エンジン１の排気通路２に、フィルタ１１、アンモニア等を噴出できる還元剤供給装置６、ＳＣＲ触媒５を設けて配置する。ここで、ＳＣＲ触媒５には、直径２６７ｍｍ、全長Ｌ２００ｍｍ、隔壁のピッチ１．０６ｍｍで、隔壁厚さ０．１１ｍｍの隔壁構造を有し、隔壁の気孔率が３０％、平均細孔径が５μｍのコージェライト質セラミックハニカム構造体に、Ｖ２Ｏ５、ＷＯ３、ＴｉＯ２を担持して、形成した。そして、還元剤供給装置６はアンモニア水や液体アンモニアや尿素水溶液を還元剤タンク６ａから排気通路２内に噴霧できる還元剤噴射弁６ｂを備えて形成した。 For the honeycomb filter, a catalyst material made of platinum (Pt), cerium oxide, and activated alumina is applied to the partition wall surface and inside the pores in the partition wall, and further to the plugging portion surface and the pores in the plugging portion. It was carried inside. The supported amount was 2 g / L in terms of Pt amount (meaning 2 g supported per 1 L of honeycomb filter volume).
As shown in FIG. 2, the filter 11 created as described above is disposed in the exhaust passage 2 of the engine 1 with a filter 11, a reducing agent supply device 6 that can eject ammonia and the like, and an SCR catalyst 5. Here, the SCR catalyst 5 has a partition structure having a diameter of 267 mm, a total length of L 200 mm, a partition pitch of 1.06 mm, and a partition wall thickness of 0.11 mm, a partition wall porosity of 30%, and an average pore diameter of 5 μm. A cordierite ceramic honeycomb structure was formed by supporting V 2 O 5 , WO 3 and TiO 2 . The reducing agent supply device 6 is formed with a reducing agent injection valve 6b that can spray ammonia water, liquid ammonia, or aqueous urea solution into the exhaust passage 2 from the reducing agent tank 6a.

以上の構成による本発明の排気ガス浄化装置は、外径２６７ｍｍ、全長３０５ｍｍの多孔質セラミックハニカム構造体の所望の流路を目封止したセラミックハニカムフィルタの、少なくとも一つの排気ガス流入側目封止部が排気ガス流入側端面より離れて配置されていると共に、隔壁及び／または目封止部の少なくとも一部に触媒物質が担持されているセラミックハニカムフィルタ１１及び外径２６７ｍｍ、全長２００ｍｍのセラミックハニカム構造体に触媒物質が担持されているＳＣＲ触媒５とをこの順序で配置しており、それぞれの容積は、セラミックハニカムフィルタが１７０７７ｃｍ３、ＳＣＲ触媒が１１１９８ｃｍ３であり、排気ガス装置全体に必要なセラミックハニカム構造体の長さは５０５ｍｍ、容積は２８２７５ｃｍ３となる。 The exhaust gas purification apparatus of the present invention having the above-described configuration is provided with at least one exhaust gas inflow side plugging of a ceramic honeycomb filter in which a desired flow path of a porous ceramic honeycomb structure having an outer diameter of 267 mm and a total length of 305 mm is plugged. The ceramic honeycomb filter 11 in which the stop portion is arranged away from the end surface on the exhaust gas inflow side and the catalytic substance is supported on at least a part of the partition wall and / or the plugging portion, and the ceramic having an outer diameter of 267 mm and a total length of 200 mm the SCR catalyst 5 in the honeycomb structure catalyst material is supported and arranged in this order, each of the volume, the ceramic honeycomb filter is 17077Cm 3, the SCR catalyst is 11198Cm 3, required the entire exhaust system The ceramic honeycomb structure has a length of 505 mm and a volume of 28275 cm 3 Become.

以上の構成による排気ガス浄化装置は、エンジン１の下流側の排気通路２に、上流側から順に、多孔質セラミックハニカム構造体の所望の流路を目封止したセラミックハニカムフィルタの、少なくとも一つの排気ガス流入側目封止部が排気ガス流入側端面より離れて配置されていると共に、隔壁及び／または目封止部の少なくとも一部に触媒物質が担持されているフィルタ１１、アンモニア等を噴出できる還元剤供給装置６、ＳＣＲ触媒５を設けて構成されていることから、次のように浄化される。フィルタ１１への粒子状物質の捕集量が多くなると、フィルタの目詰まりによる圧力損失の上昇を避けるため、ディーゼルエンジン１の運転状態に応じて、触媒物質を担持させたフィルタ上への微粒子の堆積量を推定した上で、フィルタの上流側に燃料を未燃のまま噴射して、前記触媒物質上で、燃料の酸化反応を促し、その反応熱によりフィルタの内部温度を前記触媒物質の活性下限温度以上に維持させ、堆積した微粒子を燃焼させる。この時、セラミックハニカムフィルタ１１の排気ガス流入側目封止部が排気ガス流入側端面より離れて配置されているため、目封止部の温度が触媒物質の活性化温度以上に維持され、排気ガス流入側目封止部の流入側端面への微粒子堆積による、流路閉塞を原因とする、フィルタ１１の圧力損失上昇を低減させることが可能となる。また、このような構成のフィルタから排出される排気ガス中に、ＮＯ及びＮＯ２が含まれ、且つ、このＮＯ及びＮＯ２のモル比をＮＯ／ＮＯ２で１／２〜２／１とした排気ガスが得られ易いため、これに、還元剤供給装置から還元剤であるアンモニアを添加してガス混合物を形成し、このガス混合物をＳＣＲ触媒上に導入させると、ＮＯxからＮ２への転化率が増加し、ＮＯｘがＮ２に高効率で転化されて浄化される。 The exhaust gas purifying apparatus having the above-described configuration includes at least one ceramic honeycomb filter in which a desired flow path of the porous ceramic honeycomb structure is plugged in the exhaust passage 2 on the downstream side of the engine 1 in order from the upstream side. The exhaust gas inflow side plugging portion is disposed away from the exhaust gas inflow side end face, and the filter 11 in which the catalyst substance is supported on at least a part of the partition wall and / or the plugging portion, and ammonia are ejected. Since the reducing agent supply device 6 and the SCR catalyst 5 that can be produced are provided, purification is performed as follows. When the amount of particulate matter collected on the filter 11 increases, in order to avoid an increase in pressure loss due to clogging of the filter, in accordance with the operating state of the diesel engine 1, fine particles on the filter carrying the catalyst material are collected. After estimating the amount of deposition, fuel is injected unburned upstream of the filter to promote the oxidation reaction of the fuel on the catalyst material, and the heat of reaction causes the internal temperature of the filter to be the activity of the catalyst material. Maintain above the minimum temperature and burn the deposited particulates. At this time, since the exhaust gas inflow side plugging portion of the ceramic honeycomb filter 11 is arranged away from the end surface of the exhaust gas inflow side, the temperature of the plugging portion is maintained to be equal to or higher than the activation temperature of the catalyst substance, It is possible to reduce an increase in pressure loss of the filter 11 due to flow path blockage due to particulate accumulation on the inflow side end face of the gas inflow side plugging portion. Further, the exhaust gas discharged from such configuration of the filter, include NO and NO 2, and, the molar ratio of NO and NO 2 was at 1 / 2~2 / 1 NO / NO 2 Since it is easy to obtain exhaust gas, ammonia, which is a reducing agent, is added to the exhaust gas from the reducing agent supply device to form a gas mixture, and when this gas mixture is introduced onto the SCR catalyst, NO x is converted to N 2 . The conversion rate increases and NO x is converted to N 2 with high efficiency and purified.

（従来例）
従来例について、図４を用いて説明する。
カオリン、タルク、シリカ、水酸化アルミ、アルミナなどのコージェライト生成原料粉末に、成形助剤を添加し、規定量の水を注入して更に十分な混合を行い、ハニカム構造に押出成形可能な坏土を調整した。そして、公知の押出成形用金型を用い押出成形し、外周壁と、この外周壁の内周側で隔壁により囲まれた断面が四角形状の流路を有するハニカム構造の成形体を作製し、乾燥後焼成を行い、外径２６７ｍｍ、全長１５２ｍｍ、隔壁のピッチ１．４６ｍｍで、隔壁厚さ０．２ｍｍの隔壁構造を有し、隔壁の気孔率が３５％、平均細孔径が５μｍのセラミックハニカム構造体を作製した。
前記のセラミックハニカム構造体に対して、白金（Ｐｔ）、酸化セリウム、及び活性アルミナからなる触媒物質を隔壁表面及び隔壁中の細孔内部、担持させた。担持量はＰｔ量で２ｇ／Ｌとし、ハニカム構造体にＰｔ、酸化セリウム、及び活性アルミナからなる触媒物質を含有する酸化触媒３を作成した。
一方、実施例と同様の方法により、外径２６７ｍｍ、全長３０５ｍｍ、隔壁のピッチ１．５ｍｍ、隔壁厚さ０．３ｍｍの隔壁構造を有し、隔壁の気孔率が６５％、平均細孔径が２０μｍのセラミックハニカム構造体を作製した。次に、ハニカム構造体の排気ガス流入側端面にマスキングフィルムを接着剤で貼り付け、市松模様となるように穿孔し、この孔からスラリー状の目封止材を導入、ハニカム構造体の端部に充填した。その後、目封止材が隔壁に着肉して、保形性が得られた後、マスキングフィルムを除去し、目封止材の乾燥を行った。同様に、ハニカム構造体の排気ガス流出側端面にも目封止部を形成した後、バッチ式焼成炉を用いて温度制御しつつ目封止材の焼成を行い、セラミックハニカム構造体の所望の流路を端部で目封止した。更に、Ｐｔ、酸化セリウム、及び活性アルミナからなる触媒物質を隔壁表面及び隔壁中の細孔内部、更には目封止部表面及び目封止部中の細孔内部に担持させたセラミックハニカムフィルタ４を得た。担持量はＰｔ量で２ｇ／Ｌとした。
更に、実施例と同様の方法で、直径２６７ｍｍ、全長Ｌ２００ｍｍ、隔壁のピッチ１．０６ｍｍで、隔壁厚さ０．１１ｍｍの隔壁構造を有し、隔壁の気孔率が３０％、平均細孔径が５μｍのコージェライト質セラミックハニカム構造体に、、Ｖ２Ｏ５、ＷＯ３、ＴｉＯ２を担持して、形成した。
上記のように作成したフィルタ４を、図４に示すように、エンジン１の排気通路２に、酸化触媒３、フィルタ４、アンモニア等を噴出できる還元剤供給装置６、ＳＣＲ触媒５を設けて配置する。また、還元剤供給装置６はアンモニア水や液体アンモニアや尿素水溶液を元剤タンク６ａから排気通路２内に噴霧できる還元剤噴射弁６ｂを備えて形成される。 (Conventional example)
A conventional example will be described with reference to FIG.
A cordierite-forming raw material powder such as kaolin, talc, silica, aluminum hydroxide, and alumina can be extruded into a honeycomb structure by adding a molding aid, injecting a specified amount of water, and further mixing. Adjusted the soil. Then, extrusion molding using a known extrusion mold, to produce a honeycomb structure molded body having a square-shaped passage surrounded by a partition wall on the outer peripheral wall and the inner peripheral side of the outer peripheral wall, A ceramic honeycomb having a partition wall structure having an outer diameter of 267 mm, a total length of 152 mm, a partition wall pitch of 1.46 mm, a partition wall thickness of 0.2 mm, a partition wall porosity of 35%, and an average pore diameter of 5 μm. A structure was produced.
A catalyst substance composed of platinum (Pt), cerium oxide, and activated alumina was supported on the ceramic honeycomb structure on the partition wall surface and inside the pores in the partition wall. The supported amount was 2 g / L in terms of Pt, and an oxidation catalyst 3 containing a catalyst material composed of Pt, cerium oxide, and activated alumina in the honeycomb structure was prepared.
On the other hand, according to the same method as in the example, it has a partition structure with an outer diameter of 267 mm, an overall length of 305 mm, a partition pitch of 1.5 mm, and a partition wall thickness of 0.3 mm, a partition wall porosity of 65%, and an average pore diameter of 20 μm. A ceramic honeycomb structure was prepared. Next, a masking film is attached to the exhaust gas inflow side end face of the honeycomb structure with an adhesive, and a hole is formed so as to have a checkered pattern, and a slurry-like plugging material is introduced from this hole. Filled. Then, after the plugging material was attached to the partition walls and shape retention was obtained, the masking film was removed and the plugging material was dried. Similarly, after forming a plugging portion on the exhaust gas outflow side end surface of the honeycomb structure, the plugging material is fired while controlling the temperature using a batch-type firing furnace, and a desired honeycomb honeycomb structure is obtained. The channel was plugged at the end. Further, a ceramic honeycomb filter 4 in which a catalyst material composed of Pt, cerium oxide, and activated alumina is supported on the partition wall surface and inside the pores in the partition wall, and further on the plugging portion surface and inside the pores in the plugging portion. Got. The supported amount was 2 g / L in terms of Pt amount.
Further, in the same manner as in the example, it has a partition structure with a diameter of 267 mm, an overall length of L 200 mm, a partition pitch of 1.06 mm, and a partition wall thickness of 0.11 mm, a partition wall porosity of 30%, and an average pore diameter of 5 μm. This cordierite ceramic honeycomb structure was formed by supporting V 2 O 5 , WO 3 and TiO 2 .
As shown in FIG. 4, the filter 4 created as described above is disposed in the exhaust passage 2 of the engine 1 by providing an oxidation catalyst 3, a filter 4, a reducing agent supply device 6 that can eject ammonia and the like, and an SCR catalyst 5. To do. The reducing agent supply device 6 includes a reducing agent injection valve 6b that can spray ammonia water, liquid ammonia, or an aqueous urea solution into the exhaust passage 2 from the base agent tank 6a.

以上の構成による従来例の排気ガス浄化装置は、セラミックハニカム構造体に酸化触媒物質が担持された酸化触媒３、多孔質セラミックハニカム構造体の所望の流路を両端部で目封止し、かつ隔壁及び／または目封止部の少なくとも一部に触媒物質が担持されているセラミックハニカムフィルタ４、セラミックハニカム構造体に触媒物質が担持されているＳＣＲ触媒５とをこの順序で配置しており、それぞれの外径、全長、容積は、酸化触媒３が外径２６７ｍｍ、全長１５２ｍｍ、容積８５１０ｃｍ３、セラミックハニカムフィルタ４が外径２６７ｍｍ、全長３０５ｍｍ、容積１７０７７ｃｍ３、ＳＣＲ触媒５が外径２６７ｍｍ、全長２００ｍｍ、容積１１１９８ｃｍ３であり、排気ガス装置全体に必要なセラミックハニカム構造体の長さは６５７ｍｍ、容積は３６７８５ｃｍ３となる。 The exhaust gas purifying apparatus according to the conventional example having the above-described configuration plugs the oxidation catalyst 3 in which the oxidation catalyst material is supported on the ceramic honeycomb structure, the desired flow path of the porous ceramic honeycomb structure at both ends, and The ceramic honeycomb filter 4 in which the catalyst material is supported on at least a part of the partition walls and / or the plugged portions, and the SCR catalyst 5 in which the catalyst material is supported on the ceramic honeycomb structure are arranged in this order, The outer diameter, total length, and volume of each of the oxidation catalyst 3 are 267 mm in outer diameter, 152 mm in total length, 8510 cm 3 in volume, the ceramic honeycomb filter 4 is 267 mm in outer diameter, 305 mm in total length, 17077 cm 3 in volume, and SCR catalyst 5 is 267 mm in outer diameter. 200 mm, a volume 11198cm 3, the length of the ceramic honeycomb structure required entire exhaust gas system Is 657mm, the volume becomes a 36785cm 3.

以上の構成による従来例の排気ガス浄化装置は、エンジン１の下流側の排気通路２に、上流側から順に、酸化触媒３、多孔質セラミックハニカム構造体の所望の流路を両端部で目封止し、且つ隔壁及び／または目封止部の少なくとも一部に触媒物質が担持されているフィルタ４、アンモニア等を噴出できる還元剤供給装置６、ＳＣＲ触媒５を設けて構成されていることから、次のように浄化される。フィルタ４への粒子状物質の捕集量が多くなると、フィルタの目詰まりによる圧力損失の上昇を避けるため、ディーゼルエンジン１の運転状態に応じて、触媒物質を担持させたフィルタ上への微粒子の堆積量を推定した上で、酸化触媒３の上流側に燃料を未燃のまま噴射して、前記酸化触媒物質上で、燃料の酸化反応を促すとともに、排気ガス中のＮＯをＮＯ２に効果的に転化させ、前記反応熱によりフィルタ４の内部温度を上昇させ、セラミックハニカムフィルタ４で排気ガス中の粒子状物質の少なくとも一部がＮＯ２の存在下で比較的低い温度で燃焼除去させる。更に、ＮＯ２含有量の高くなった排気ガスに対して、窒素系還元剤を添加してガス混合物を形成し、このガス混合物をＳＣＲ触媒上に通過させることにより、窒素酸化物（ＮＯｘ）がＮ２に転化されて、浄化される。但し、この従来例の排気ガス浄化装置では、酸化触媒３とセラミックハニカムフィルタ４が排気通路によって、直列に配置されていることから、酸化触媒における触媒反応により高温となった排気ガスが、酸化触媒とフィルタ間の排気通路を通過する間に温度が低下してフィルタに流入し、特に低速走行時のように浄化装置に流入する排気ガス温度自体が低い場合は、フィルタ内の温度が、粒子状物質を十分に燃焼させる温度に達しない場合があり、未燃焼の粒子状物質が特にフィルタの中でも最も温度の低くなるフィルタ流入側目封止部端面に残存して、流路を閉塞させて、フィルタの圧力損失を上昇させるという問題が発生した。また、このような構成のフィルタから排出される排気ガス中のＮＯ／ＮＯ２のモル比は１／３〜４／１と広い範囲のモル比の排気ガスが得られるため、これに、還元剤供給装置から還元剤であるアンモニアを添加してガス混合物を形成し、このガス混合物をＳＣＲ触媒上に導入させると、モル比によってはＮＯxからＮ２への転化率が低下する場合もある。 In the conventional exhaust gas purifying apparatus having the above configuration, the oxidation catalyst 3 and the desired flow path of the porous ceramic honeycomb structure are sealed at both ends in the exhaust passage 2 on the downstream side of the engine 1 in order from the upstream side. And a filter 4 in which a catalytic substance is supported on at least a part of the partition walls and / or plugging portions, a reducing agent supply device 6 that can eject ammonia and the like, and an SCR catalyst 5 are provided. It is purified as follows. When the amount of particulate matter trapped in the filter 4 increases, in order to avoid an increase in pressure loss due to clogging of the filter, in accordance with the operating state of the diesel engine 1, fine particles on the filter carrying the catalyst material are collected. After estimating the amount of deposition, fuel is injected unburned upstream of the oxidation catalyst 3 to promote an oxidation reaction of the fuel on the oxidation catalyst material, and NO in the exhaust gas is effective for NO 2 The internal temperature of the filter 4 is increased by the reaction heat, and at least a part of the particulate matter in the exhaust gas is burned and removed at a relatively low temperature in the presence of NO 2 by the ceramic honeycomb filter 4. Further, a nitrogen-based reducing agent is added to the exhaust gas having a high NO 2 content to form a gas mixture, and this gas mixture is passed over the SCR catalyst, so that nitrogen oxides (NO x ). Is converted to N 2 and purified. However, in the exhaust gas purifying apparatus of this conventional example, since the oxidation catalyst 3 and the ceramic honeycomb filter 4 are arranged in series by the exhaust passage, the exhaust gas that has become a high temperature due to the catalytic reaction in the oxidation catalyst is converted into the oxidation catalyst. When passing through the exhaust passage between the filter and the filter, the temperature drops and flows into the filter. Especially when the exhaust gas temperature itself flowing into the purification device is low, such as during low speed running, the temperature inside the filter The temperature at which the substance is sufficiently combusted may not be reached, and unburned particulate matter remains on the end face of the filter inflow side plugging portion where the temperature is the lowest among the filters, blocking the flow path, There was a problem of increasing the pressure loss of the filter. Further, since the exhaust gas having a wide range of molar ratio of NO / NO 2 in the exhaust gas exhausted from the filter having such a configuration is obtained in the range of 1/3 to 4/1, the reducing agent is added to the exhaust gas. When ammonia, which is a reducing agent, is added from a supply device to form a gas mixture and this gas mixture is introduced onto the SCR catalyst, the conversion rate from NO x to N 2 may decrease depending on the molar ratio.

以上、説明したように本発明の実施例による排気ガス浄化装置では、フィルタ１１が、触媒物質の作用により粒子状物質を効果的に燃焼浄化する機能を有しているため、本発明の排気ガス浄化装置は、フィルター１１、及びＳＣＲ触媒５とで構成され、排気ガス装置全体に必要なセラミックハニカム構造体の長さは５０５ｍｍ、容積は２８２７５ｃｍ３であるのに対し、比較例の排気ガス浄化装置では、排気ガス装置全体に必要なセラミックハニカム構造体の長さは６５７ｍｍ、容積は３６７８５ｃｍ３であり、本発明の排気ガス浄化装置によれば、粒子状物質及び窒素酸化物（ＮＯｘ）の浄化率を高く維持できるとともに、排気ガス浄化装置全体の圧力損失を低減できるという大きな効果が得られる。また本発明の排気ガス浄化装置に必要なハニカム構造体はフィルター１１、及びＳＣＲ触媒５となるため、従来技術のように酸化触媒、セラミックハニカムフィルタ、ＳＣＲ触媒を配設した排気ガス浄化装置に比べ圧力損失が低く押さえられることから、浄化装置全体の小型化が可能となる。 As described above, in the exhaust gas purifying apparatus according to the embodiment of the present invention, since the filter 11 has a function of effectively burning and purifying the particulate matter by the action of the catalytic substance, the exhaust gas of the present invention. The purification device includes the filter 11 and the SCR catalyst 5, and the length of the ceramic honeycomb structure necessary for the entire exhaust gas device is 505 mm and the volume is 28275 cm 3 , whereas the exhaust gas purification device of the comparative example Then, the length of the ceramic honeycomb structure required for the entire exhaust gas apparatus is 657 mm, and the volume is 36785 cm 3. According to the exhaust gas purification apparatus of the present invention, the particulate matter and nitrogen oxide (NO x ) can be purified. A large effect can be obtained that the rate can be maintained high and the pressure loss of the entire exhaust gas purification device can be reduced. Further, since the honeycomb structure necessary for the exhaust gas purifying apparatus of the present invention is the filter 11 and the SCR catalyst 5, as compared with the exhaust gas purifying apparatus in which the oxidation catalyst, the ceramic honeycomb filter, and the SCR catalyst are disposed as in the prior art. Since the pressure loss is kept low, the entire purification device can be downsized.

本発明の排気ガス浄化装置を示すディーゼルエンジンの排気系の構成図である。It is a block diagram of the exhaust system of the diesel engine which shows the exhaust gas purification apparatus of this invention. 本発明の実施の形態でのハニカムフィルタの模式断面図である。It is a schematic cross section of a honeycomb filter in an embodiment of the present invention. ハニカム構造体に目封止材を導入している状況を示す模式断面図であるFIG. 3 is a schematic cross-sectional view illustrating a situation where a plugging material is introduced into a honeycomb structure. 従来の排気ガス浄化装置を示すディーゼルエンジンの排気系の構成図である。It is a block diagram of the exhaust system of the diesel engine which shows the conventional exhaust gas purification apparatus.

符号の説明Explanation of symbols

１：エンジン
２：排気通路
３：酸化触媒
４：フィルタ
５：ＳＣＲ触媒
６：還元剤供給装置
７：排気ガス
１０：ハニカム構造体
１１：ハニカムフィルタ
１２：流入側端面
１３：流出側端面
２０：外周壁
３０：隔壁
３１：流入側目封止部より流入側の隔壁
３２：流入側目封止部より流出側の隔壁
４０：流路
４１：流入側端面で開口している流路
４２：流入側端面で開口している流路
４３：排気ガス流出側に開口した流路
５０：流入側目封止部
５１：流入側目封止部端面
５２：流出側目封止部
５３：目封止材
６０：触媒物質
７０：未燃焼微粒子
８０：マスク
８１：スラリー導入通路
９０：排気ガスの流入
９１：排気ガスの流入
９２：排気ガスの流出
Ｘ：目封止部形成位置
1: Engine 2: Exhaust passage 3: Oxidation catalyst 4: Filter 5: SCR catalyst 6: Reducing agent supply device 7: Exhaust gas 10: Honeycomb structure 11: Honeycomb filter 12: Inlet side end face 13: Outlet side end face 20: Outer periphery Wall 30: partition wall 31: partition wall on the inflow side from the inflow side plugging portion 32: partition wall on the outflow side from the inflow side plugging portion 40: channel 41: channel 42 opened on the end surface of the inflow side: inflow side Flow path 43 opened at the end face: Flow path opened to the exhaust gas outflow side 50: Inflow side plugging section 51: Inflow side plugging section end face 52: Outflow side plugging section 53: Plugging material 60: catalyst material 70: unburned particulates 80: mask 81: slurry introduction passage 90: exhaust gas inflow 91: exhaust gas inflow 92: exhaust gas outflow X: plugging portion formation position

Claims (5)

ディーゼルエンジンから排出される窒素酸化物及び粒子状物質を含有する排気ガスを浄化する装置であって、多孔質セラミックハニカム構造体の所望の流路を目封止したセラミックハニカムフィルタの、少なくとも一つの排気ガス流入側目封止部が排気ガス流入側端面より離れて配置されていると共に、隔壁及び／または目封止部の少なくとも一部に触媒物質が担持されているフィルタと、ＳＣＲ触媒とを、この順序で配置したことを特徴とする排気ガス浄化装置。 An apparatus for purifying exhaust gas containing nitrogen oxides and particulate matter discharged from a diesel engine, comprising at least one ceramic honeycomb filter plugging a desired flow path of a porous ceramic honeycomb structure An exhaust gas inflow side plugged portion is disposed away from an end surface of the exhaust gas inflow side, and a filter in which a catalytic material is supported on at least a part of the partition wall and / or the plugged portion, and an SCR catalyst, The exhaust gas purifying device is arranged in this order. 前記セラミックハニカムフィルタの排気ガス流入側目封止部端面が、セラミックハニカムフィルタの流入側端面から該セラミックハニカムフィルタ全長の０．７倍以下の長さの区間に配置されていることを特徴とする請求項１に記載の排気ガス浄化装置。 The exhaust gas inflow side plugging portion end face of the ceramic honeycomb filter is disposed in a section having a length not more than 0.7 times the total length of the ceramic honeycomb filter from the inflow side end face of the ceramic honeycomb filter. The exhaust gas purification apparatus according to claim 1. 前記セラミックハニカムフィルタに担持される触媒物質が白金族金属を含んでなることを特徴とする請求項１乃至２のいずれかに記載の排気ガス浄化装置。 The exhaust gas purification device according to any one of claims 1 to 2, wherein the catalyst substance supported on the ceramic honeycomb filter comprises a platinum group metal. 前記セラミックハニカムフィルタの排気ガス流入側の隔壁に担持された触媒物質の活性度が、排気ガス流出側の隔壁に担持された触媒物質の活性度に比べ高いことを特徴とする請求項１乃至３のいずれかに記載のセラミックハニカムフィルタ。 4. The activity of the catalyst material supported on the partition wall on the exhaust gas inflow side of the ceramic honeycomb filter is higher than the activity of the catalyst material supported on the partition wall on the exhaust gas outflow side. The ceramic honeycomb filter according to any one of the above. ディーゼルエンジンから排出される窒素酸化物及び粒子状物質を含有する排気ガスを浄化する装置に配設されたセラミックハニカムフィルタの、少なくとも一つの排気ガス流入側目封止部が排気ガス流入側端面より離れて配置されていると共に、隔壁及び／または目封止部の少なくとも一部に触媒物質が担持され、前記排気ガス中の粒子状物質を前記セラミックハニカムフィルタ内で燃焼させ、前記フィルタの排気ガス排出側に配設されたＳＣＲ触媒中に導入する排気ガス中のＮＯ／ＮＯ２のモル比を１／２〜２／１にすることを特徴とする排気ガス浄化方法。
At least one exhaust gas inflow side plugging portion of the ceramic honeycomb filter disposed in the device for purifying exhaust gas containing nitrogen oxides and particulate matter discharged from the diesel engine is from the exhaust gas inflow side end surface. The catalyst material is supported on at least a part of the partition walls and / or the plugging portions, and the particulate matter in the exhaust gas is burned in the ceramic honeycomb filter, and the exhaust gas of the filter An exhaust gas purification method, wherein the molar ratio of NO / NO 2 in the exhaust gas introduced into the SCR catalyst arranged on the exhaust side is set to 1/2 to 2/1.
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