JPH02108806A - Exhaust gas purifying device for diesel engine - Google Patents
Exhaust gas purifying device for diesel engineInfo
- Publication number
- JPH02108806A JPH02108806A JP63259419A JP25941988A JPH02108806A JP H02108806 A JPH02108806 A JP H02108806A JP 63259419 A JP63259419 A JP 63259419A JP 25941988 A JP25941988 A JP 25941988A JP H02108806 A JPH02108806 A JP H02108806A
- Authority
- JP
- Japan
- Prior art keywords
- honeycomb
- catalyst
- oxidation catalyst
- exhaust
- catalytic
- 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.)
- Pending
Links
- 239000003054 catalyst Substances 0.000 claims abstract description 68
- 230000003647 oxidation Effects 0.000 claims abstract description 45
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 45
- 239000012041 precatalyst Substances 0.000 claims description 18
- 238000000746 purification Methods 0.000 claims description 16
- 239000000463 material Substances 0.000 abstract description 9
- 229910052878 cordierite Inorganic materials 0.000 abstract description 5
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 abstract description 5
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 abstract description 4
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 abstract description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 abstract description 3
- 229910052802 copper Inorganic materials 0.000 abstract description 3
- 239000010949 copper Substances 0.000 abstract description 3
- XHCLAFWTIXFWPH-UHFFFAOYSA-N [O-2].[O-2].[O-2].[O-2].[O-2].[V+5].[V+5] Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[V+5].[V+5] XHCLAFWTIXFWPH-UHFFFAOYSA-N 0.000 abstract description 2
- KPZUWETZTXCDED-UHFFFAOYSA-N [V].[Cu] Chemical compound [V].[Cu] KPZUWETZTXCDED-UHFFFAOYSA-N 0.000 abstract description 2
- 229910052763 palladium Inorganic materials 0.000 abstract description 2
- 229910052697 platinum Inorganic materials 0.000 abstract description 2
- 229910001935 vanadium oxide Inorganic materials 0.000 abstract description 2
- 230000003197 catalytic effect Effects 0.000 abstract 7
- 239000000969 carrier Substances 0.000 abstract 1
- 150000001875 compounds Chemical class 0.000 abstract 1
- 230000000717 retained effect Effects 0.000 abstract 1
- 241000264877 Hippospongia communis Species 0.000 description 43
- 239000007789 gas Substances 0.000 description 11
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 6
- 125000002485 formyl group Chemical class [H]C(*)=O 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 239000008188 pellet Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- 230000006866 deterioration Effects 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical class [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000000567 combustion gas Substances 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 230000008929 regeneration Effects 0.000 description 2
- 238000011069 regeneration method Methods 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- 229910021536 Zeolite Inorganic materials 0.000 description 1
- BGKBQRFXFZEARY-UHFFFAOYSA-N [V].[Pt] Chemical compound [V].[Pt] BGKBQRFXFZEARY-UHFFFAOYSA-N 0.000 description 1
- 239000003463 adsorbent Substances 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 229910002090 carbon oxide Inorganic materials 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000001877 deodorizing effect Effects 0.000 description 1
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 1
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- 230000009965 odorless effect Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000004071 soot Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 1
- 239000010457 zeolite Substances 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B3/00—Engines characterised by air compression and subsequent fuel addition
- F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は触媒を使用したディーゼルエンジンの排気浄化
装置の改良に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in an exhaust purification device for a diesel engine using a catalyst.
〔従来の技術］
第５図及び第６図に酸化触媒を使用する排気浄化装置の
従来例を示す。第５図はペレット状の触媒担体を使用し
たもので、ケーシングｌの中には両端を閉じた多孔の円
筒２が支持され、図の左側から挿入された排気入口管３
がケーシングｌと多孔円筒２の端壁を貫通しており、多
孔円筒２内において多数の小孔を設けられている。多孔
円筒２内には排気入口管３の多孔部分との間に触媒ベレ
ット４が充填されている。５は排気出口管である。[Prior Art] FIGS. 5 and 6 show a conventional example of an exhaust purification device using an oxidation catalyst. Fig. 5 shows a catalyst carrier in the form of pellets, in which a porous cylinder 2 with both ends closed is supported in the casing l, and an exhaust inlet pipe 3 inserted from the left side of the figure.
passes through the casing l and the end wall of the perforated cylinder 2, and a large number of small holes are provided within the perforated cylinder 2. A catalyst pellet 4 is filled in the porous cylinder 2 between it and the porous portion of the exhaust inlet pipe 3. 5 is an exhaust outlet pipe.
排気入口管３からケーシング１内に導入された排気は入
口管３の多孔部分から触媒ベレット層に入り、ベレット
の隙間を流れる間に排気中の炭化水素、−酸化炭素、臭
気の原因物質であるアルデヒド等は酸化され、無害とな
った排気は多孔円筒２の小孔からケーシング１との間隙
に出て、排気出口管５から導出される。Exhaust gas introduced into the casing 1 from the exhaust inlet pipe 3 enters the catalyst pellet layer through the porous portion of the inlet pipe 3, and while flowing through the gaps between the pellets, hydrocarbons, carbon oxides, and odor-causing substances in the exhaust gas are absorbed. Aldehydes and the like are oxidized, and the harmless exhaust gas exits from the small holes of the porous cylinder 2 into the gap with the casing 1 and is led out from the exhaust outlet pipe 5.
第６図はハニカム状の触媒担体を使用したもので、ケー
シング１内には軸方向に多数の貫通孔６を有する多孔質
の触媒ハニカム７が耐熱性のある緩衝材を介してケーシ
ング１内に支持される。排気入口管３から導入された排
気は触媒ハニカム７の多数の貫通孔６に分流し、鎖孔を
流れる間に有害物質は酸化されて無害化し排気出口管５
から導出される。Fig. 6 shows a case using a honeycomb-shaped catalyst carrier, in which a porous catalyst honeycomb 7 having a large number of through holes 6 in the axial direction is inserted into the casing 1 through a heat-resistant buffer material. Supported. Exhaust gas introduced from the exhaust inlet pipe 3 is divided into a large number of through holes 6 of the catalyst honeycomb 7, and while flowing through the chain holes, harmful substances are oxidized and rendered harmless.
It is derived from
ディーゼルエンジンの排気を前記のような従来の酸化触
媒による浄化装置によって処理する場合には、当初は十
分な浄化能力を持っていた浄化装置が、比較的短期間で
著しく浄化能力が低下してしまうという問題がある。When diesel engine exhaust is treated using a conventional oxidation catalyst-based purification device as described above, the purification device initially had sufficient purification ability, but its purification ability drops significantly in a relatively short period of time. There is a problem.
これは、ディーゼルエンジンの排気にはガソリンエンジ
ン等とは異なり、「ディーゼルパティキュレート」と呼
ばれている主として遊離炭素粒（煤）からなる固体の微
粒子が多量に含まれており（以下これをパティキュレー
トという）、これがペレ・ントやハニカム状の触媒担体
の表面に付着してそれを覆い、触媒としての作用を阻害
するためであることが判っている。パティキュレートは
可燃性の炭素の微粒子であるから、高温下では燃焼して
Ｃｏ２等の気体となり消失するものではあるが、その着
火温度は６００°Ｃ程度、又一般の酸化触媒を用いても
５００°Ｃ程度と高く、通常、ディーゼルエンジンの排
気温度が８０〜１２０°Ｃ１高出力運転の状態でも３５
０〜４００°Ｃ程度であるため容易に着火せず、触媒の
表面に堆積して触媒の機能を低下させるのである。パテ
ィキュレートによって覆われた触媒は、たはえば２００
時間毎にそれをケーシング１からとり出してガスバーナ
ーで加熱焼成処理してパティキュレートを焼却している
が、この作業は面倒で手数を要するだけでなく、短時間
内に高熱をかける焼成によって触媒が熱劣化を起こすた
めに、浄化能力が完全には回復しないという問題もある
。This is because, unlike gasoline engine exhaust, diesel engine exhaust contains large amounts of solid particulates mainly consisting of free carbon particles (soot) called "diesel particulates" (hereinafter referred to as particulates). It is known that this is because this substance adheres to the surface of the pellet or honeycomb-shaped catalyst carrier, covering it and inhibiting its action as a catalyst. Particulates are fine particles of combustible carbon, so at high temperatures they burn and become gases such as Co2 and disappear, but their ignition temperature is around 600°C, and even with a general oxidation catalyst, it is 500°C. Normally, the exhaust temperature of a diesel engine is 80 to 120°C.1 Even during high output operation, it is 35
Since the temperature is about 0 to 400°C, it does not easily ignite, and it accumulates on the surface of the catalyst, reducing the function of the catalyst. The catalyst covered by particulates is e.g.
The particulates are taken out from the casing 1 every hour and heated and fired with a gas burner to incinerate the particulates, but this process is not only troublesome and time-consuming, but also requires a short period of time to burn the particulates at high heat. There is also the problem that the purification ability does not fully recover because of thermal deterioration.
また、冷間始動時のディーゼルエンジンの排気中には炭
化水素や一酸化炭素のほかにアルデヒド類が多量に含ま
れており、特にホルムアルデヒドは刺激臭の原因物質で
あるが、これらを酸化して無害、無臭化する酸化触媒の
作用温度は１５０’Ｃと比較的高く、通常の排気温度は
前記のように８０〜１２０°Ｃ程度であるから、酸化触
媒は温度が上昇するまでアルデヒドに対して浄化作用を
もたないため、始動時はアルデヒドがそのまま排出され
てしすうという問題もある。In addition, the exhaust from a diesel engine during a cold start contains a large amount of aldehydes in addition to hydrocarbons and carbon monoxide. In particular, formaldehyde is a substance that causes a pungent odor, but it is necessary to oxidize it. The operating temperature of the oxidation catalyst, which is harmless and odorless, is relatively high at 150°C, and the normal exhaust temperature is about 80 to 120°C as mentioned above, so the oxidation catalyst does not react with aldehyde until the temperature rises. Since it does not have a purifying effect, there is also the problem that aldehyde is directly discharged during startup.
本発明は、これらの従来技術の諸問題を解決することを
発明の課題とするものである。An object of the present invention is to solve the problems of these conventional techniques.
本発明は前記の課題を解決するための手段として、排気
の入口と浄化された排気の出口とを備えるケーシング内
の排気出口側に設けられた酸化触媒と、該酸化触媒との
間に所定の間隔を保持して排気の入口側に設けられた前
置触媒とを有すると共に、前記前置触媒がディーゼルパ
ティキュレートを常態では着火不可能な低い排気温度に
おいて着火させ得る特性を有することを特徴とするディ
ーゼルエンジン用排気浄化装置を提供する。As a means for solving the above problems, the present invention provides a predetermined distance between an oxidation catalyst provided on the exhaust outlet side in a casing having an exhaust inlet and a purified exhaust outlet, and the oxidation catalyst. and a pre-catalyst provided on the exhaust inlet side with a distance therebetween, and the pre-catalyst has a characteristic of being able to ignite diesel particulates at a low exhaust temperature at which diesel particulates would normally not be ignited. The present invention provides an exhaust purification device for diesel engines.
本発明は前記の如き構成を有するから、ディーゼルエン
ジンから排出された排気は入口からケーシング内に入り
、酸化触媒において酸化処理を受けて無害化し出口から
排出されるが、その中に含まれるパティキュレートは前
置触媒及び酸化触媒に付着して捕捉される。次にディー
ゼルエンジンが高出力運転されると排気の温度が上昇し
、パティキュレートの常態における着火温度より低くて
も前置触媒の作用温度に達すると、前置触媒に付着して
いたパティキュレートが着火し燃焼する。Since the present invention has the above configuration, the exhaust gas discharged from the diesel engine enters the casing from the inlet, undergoes oxidation treatment at the oxidation catalyst, becomes harmless, and is discharged from the outlet, but the particulates contained therein are is trapped by adhering to the precatalyst and oxidation catalyst. Next, when the diesel engine is operated at high output, the exhaust temperature rises, and when it reaches the operating temperature of the precatalyst, even if it is lower than the normal ignition temperature of particulates, the particulates attached to the precatalyst are It ignites and burns.
従って前置触媒から出る排気の温度は上昇し、これが所
定の間隔をおいて出口側（下流側）に設けられている酸
化触媒の温度を上昇させ、常態におけるパティキュレー
トの着火温度を上まわる状態にするから、酸化触媒に付
着していたパティキュレートも着火して燃焼する。この
ようにして、前置触媒及び酸化触媒に付着していたパテ
ィキュレートは、通常の運転モードに含まれている高出
力運転のたびに自動的に焼却され、酸化触媒はその都度
再生処理を受けるから、酸化触媒による浄化能力は常に
良好な状態に維持される。Therefore, the temperature of the exhaust gas exiting from the precatalyst increases, which increases the temperature of the oxidation catalyst provided at the outlet side (downstream side) at predetermined intervals, and the temperature exceeds the ignition temperature of particulates under normal conditions. As a result, particulates attached to the oxidation catalyst also ignite and burn. In this way, particulates adhering to the precatalyst and oxidation catalyst are automatically incinerated every time high-output operation is included in the normal operation mode, and the oxidation catalyst is regenerated each time. Therefore, the purification ability of the oxidation catalyst is always maintained in a good condition.
第１図は本発明の第１実施例を示したもので、ケーシン
グ１、排気入口管３、排気出口管５、及び緩衝材８は従
来例と基本的に変わらない。この例ではハニカム型触媒
担体が２段に設けられており、下流側の触媒ハニカム７
は普通の酸化触媒ハニカムであって、白金やパラジウム
等の触媒物質を、細孔率を向上させたディーゼルパティ
キュレート濾適用及び自動車用の三元触媒用コージライ
トハニカムや、耐熱性にすぐれたムライトハニカム、吸
着特性の良いゼオライトハニカムやセビオライトハニカ
ム、セラミックファイバーハニカム（シリカアルミナフ
ァイバー等）、耐ＳＯｘ性のあるチタニアハニカム等の
担体に付着させたものを使用することができる。FIG. 1 shows a first embodiment of the present invention, in which a casing 1, an exhaust inlet pipe 3, an exhaust outlet pipe 5, and a buffer material 8 are basically the same as in the conventional example. In this example, the honeycomb-type catalyst carrier is provided in two stages, with the catalyst honeycomb 7 on the downstream side.
is an ordinary oxidation catalyst honeycomb, and catalyst materials such as platinum and palladium are applied to diesel particulate filters with improved porosity, cordierite honeycombs for three-way catalysts for automobiles, and mullite with excellent heat resistance. Those attached to a carrier such as honeycomb, zeolite honeycomb or Seviolite honeycomb with good adsorption properties, ceramic fiber honeycomb (silica alumina fiber, etc.), titania honeycomb with SOx resistance, etc. can be used.
酸化触媒ハニカム７の上流側には間隔９をおいて、ディ
ーゼルパティキュレートを３５０〜４００°Ｃ程度の温
度でも着火させ得る特殊な前置触媒ハニカム１０が設け
られる。前置触媒ハニカムｌＯは、例えば酸化バナジウ
ム系、銅系、あるいはバナジウム−銅、バナジウム−白
金等の複合系触媒物質をハニカム型担体に付着させたも
のであって、ハニカム型担体の材質は酸化触媒ハニカム
７と同様にのものを使用し得る。On the upstream side of the oxidation catalyst honeycomb 7, a special precatalyst honeycomb 10 is provided at a distance 9, which is capable of igniting diesel particulates even at temperatures of about 350 to 400°C. The pre-catalyst honeycomb lO is made by adhering, for example, a vanadium oxide-based, copper-based, or composite catalyst material such as vanadium-copper or vanadium-platinum to a honeycomb-shaped carrier, and the material of the honeycomb-shaped carrier is an oxidation catalyst. Something similar to the honeycomb 7 can be used.
ただし、ディーゼル排気臭の脱臭ということに重点を置
く場合には、前置触媒ハニカム、酸化触媒ハニカムとも
ディーゼルパティキュレート濾適用の多孔質コージライ
トハニカムを使用した方がよい。自動車用の三元触媒用
コージライトハニカムとディーゼルパティキュレート濾
適用多孔質コージライトハニカムにＶｚＯｓ／ＰＬを担
持させた場合の刺激臭物質の除去率を調べてみると、前
者が約５０％、後者が約６０％という結果が得られた。However, if emphasis is placed on deodorizing diesel exhaust odor, it is better to use porous cordierite honeycombs adapted for diesel particulate filtration for both the precatalyst honeycomb and the oxidation catalyst honeycomb. When examining the removal rate of irritating odor substances when VzOs/PL is supported on cordierite honeycomb for three-way catalysts for automobiles and porous cordierite honeycomb for diesel particulate filtration, it is found that the former is about 50% and the latter is about 50%. The result was approximately 60%.
これらの触媒ハニカム７及び１０は緩衝材８を介してケ
ーシング１内に固定する。間隔９の大きさは、狭すぎる
と前置触媒ハニカム１０からの熱によって酸化触媒ハニ
カム７が劣化するし、離しすぎると前置触媒ハニカム１
０から燃焼が酸化触媒ハニカム７へ伝播しないので、諸
条件に合わせて最適の値を決定しなければならない。These catalyst honeycombs 7 and 10 are fixed within the casing 1 via a buffer material 8. If the distance 9 is too small, the oxidation catalyst honeycomb 7 will deteriorate due to the heat from the precatalyst honeycomb 10, and if it is too far apart, the precatalyst honeycomb 1 will deteriorate.
Since combustion does not propagate to the oxidation catalyst honeycomb 7 from 0, the optimum value must be determined according to various conditions.
本実施例の排気浄化装置をたとえばフォークリフトのデ
ィーゼルエンジンに接続して使用すると、チルトリリー
フ又はリフトリリーフの全速というような、高出力運転
が暫く持続する時には、排気ガス温度が３５０°Ｃ以上
になるので、このとき、前置触媒ハニカム１０では、付
着したパティキュレートがバナジウム、銅等の触媒物質
の作用によって着火して燃焼し、前置触媒ハニカム１０
の温度は急速に上昇する。この時間と温度の関係を第２
図に示す。この場合、付着させたパティキュレートの量
は４０ｇである。そして１，０００’Ｃ前後となった高
温の燃焼ガスが間隔９を越えて酸化触媒のハニカム７に
流れ、そこに付着しているパティキュレートをも燃焼さ
せるのである。このようにしてハニカム７は再生され触
媒としての活性をとり戻すが、再生に要する時間は第２
図から判るように２〜３分程度である。従って、運転モ
ードの中で、排気ガス温度が３５０°Ｃ以上となる高出
力運転の時間が２〜３分継続するディーゼルエンジンの
使用態様であれば、それ以外の時間にハニカム上に捕捉
されたパティキュレートを高出力運転のときに焼却して
、酸化触媒ハニカム７を再生させることができ、２００
時間毎のメインテナンス等のわずられしい作業をしなく
ても、常に酸化触媒の活性を維持することが可能となる
。When the exhaust purification device of this embodiment is used by connecting it to a forklift diesel engine, for example, when high-output operation continues for a while, such as at full tilt relief or lift relief, the exhaust gas temperature will rise to 350°C or higher. Therefore, at this time, the adhering particulates are ignited and burned in the precatalyst honeycomb 10 by the action of catalyst substances such as vanadium and copper, and the precatalyst honeycomb 10
temperature rises rapidly. This relationship between time and temperature can be expressed as
As shown in the figure. In this case, the amount of particulates attached was 40 g. Then, the high-temperature combustion gas, which is around 1,000'C, flows over the gap 9 to the honeycomb 7 of the oxidation catalyst, and also burns the particulates attached thereto. In this way, the honeycomb 7 is regenerated and regains its activity as a catalyst, but the time required for regeneration is
As can be seen from the figure, it takes about 2 to 3 minutes. Therefore, in the operating mode, if the diesel engine is used in a high-output operation where the exhaust gas temperature exceeds 350°C for 2 to 3 minutes, the amount of gas trapped on the honeycomb at other times is The oxidation catalyst honeycomb 7 can be regenerated by incinerating particulates during high output operation, and the oxidation catalyst honeycomb 7 can be regenerated.
It becomes possible to maintain the activity of the oxidation catalyst at all times without having to perform troublesome operations such as hourly maintenance.
酸化触媒ハニカム７に付着するパティキュレートが、こ
のような自動的再生作用によって除去され、酸化触媒が
劣化を伴うことなく、ひんばんに活性化されるので、酸
化触媒ハニカム７のホルムアルデヒドの浄化率を従来の
場合にくらべてみると、第３図に示すような優れた結果
が得られた。The particulates adhering to the oxidation catalyst honeycomb 7 are removed by this automatic regeneration action, and the oxidation catalyst is frequently activated without deterioration, thereby increasing the formaldehyde purification rate of the oxidation catalyst honeycomb 7. When compared with the conventional case, excellent results as shown in FIG. 3 were obtained.
この場合は、直径１４．４ＣＩｌ長さ１５ｃｍの酸化触
媒ハニカムに４０ｇのパティキュレートを付着させると
いう同じ条件で比較試験を行った。In this case, a comparative test was conducted under the same conditions in which 40 g of particulates were adhered to an oxidation catalyst honeycomb with a diameter of 14.4 CI and a length of 15 cm.
第４図は本発明の第２実施例を示したものであって、第
１実施例と異なる点は、前置触媒ハニカム１０内で着火
・燃焼を均一に起こさせるために、その上流側に多孔遮
蔽板１１を設けて、排気が均一にハニカム１０に当たる
ようにしたこと、同じような理由で間隔９に多孔遮蔽板
１２を設けて高温の燃焼ガスが酸化触媒ハニカム７の面
に均一に当たるようにしたことである。また、この例で
はハニカム止め１３及び１４を設けてハニカム７゜ＩＯ
が動かないようにしている。なお、１５は前記多孔遮蔽
板１１ 、１２を固定するブラケットである。FIG. 4 shows a second embodiment of the present invention, which differs from the first embodiment in that in order to cause ignition and combustion to occur uniformly within the precatalyst honeycomb 10, the upstream side is A porous shielding plate 11 is provided so that the exhaust air hits the honeycomb 10 uniformly, and for the same reason, a porous shielding plate 12 is provided at the interval 9 so that the high temperature combustion gas hits the surface of the oxidation catalyst honeycomb 7 uniformly. This is what I did. In addition, in this example, honeycomb stoppers 13 and 14 are provided to prevent the honeycomb 7° IO.
is trying not to move. Note that 15 is a bracket for fixing the porous shielding plates 11 and 12.
浄化装置としての作動は前記第１実施例と変わらない。The operation as a purifying device is the same as in the first embodiment.
本発明は前記の手段及び作用に記載した構成を有するか
ら、触媒によって捕捉されたパティキュレートは、触媒
の機能を低下させる前に通常の運転モードに含まれる高
出力運転となったときに自動的に焼却されるので、酸化
触媒は常に良好な浄化機能を維持することができる。Since the present invention has the configuration described in the above-mentioned means and operation, particulates captured by the catalyst are automatically removed during high output operation included in the normal operation mode, before reducing the function of the catalyst. Since the oxidation catalyst is incinerated, the oxidation catalyst can always maintain a good purification function.
従って、酸化触媒をとり出して加熱焼成するメインテナ
ンス作業が不要となり、焼成による酸化触媒の劣化も避
けられる。また冷間始動時においても、多孔質ハニカム
などの高吸着性担体を使うことでアルデヒド等を一時吸
着しておくことが可能となり、さらに、パティキュレー
トの焼成によって酸化触媒の温度が早く上昇するから、
アルデヒドの浄化も始動後すみやかに始まり、ディーゼ
ルエンジン特有の臭気を放出することもない。Therefore, maintenance work such as taking out the oxidation catalyst and heating and baking it is unnecessary, and deterioration of the oxidation catalyst due to baking can be avoided. In addition, even during a cold start, by using a highly adsorbent carrier such as a porous honeycomb, it is possible to temporarily adsorb aldehydes, etc. Furthermore, the temperature of the oxidation catalyst rises quickly due to the firing of particulates. ,
Purification of aldehydes begins immediately after startup, and the engine does not emit the odor typical of diesel engines.
第１図は第１実施例を示す縦断面図、第２図は前置触媒
内のパティキュレートが着火燃焼する際の温度変化を示
す図、第３図は本発明と従来の各浄化装置のホルムアル
デヒド浄化率の変化を比較して示す図、第４図は第２実
施例を示す縦断面図、第５図及び第６図はそれぞれ従来
の浄化装置の例を示す縦断面図である。
１・・・ケーシング、 ３・・・入口管、 ５・・・出
口管、７・・・酸化触媒ハニカム、 ８・・・緩衝材、
９・・・間隔、 １０・・・前置触媒ハニカム、１１
、１２・・・多孔遮蔽板。
弗１冨
第４図
第５図
第２図
第３図
帛６図
１Ｃ・・・ｃ１１！！媒ハニカム
＋１ｊ２・・・多孔遮蔽板FIG. 1 is a longitudinal sectional view showing the first embodiment, FIG. 2 is a diagram showing temperature changes when particulates in the precatalyst are ignited and burned, and FIG. 3 is a diagram showing the differences between the present invention and conventional purification devices. FIG. 4 is a longitudinal sectional view showing a second embodiment, and FIGS. 5 and 6 are longitudinal sectional views showing examples of conventional purification apparatuses. DESCRIPTION OF SYMBOLS 1... Casing, 3... Inlet pipe, 5... Outlet pipe, 7... Oxidation catalyst honeycomb, 8... Buffer material,
9... Spacing, 10... Precatalyst honeycomb, 11
, 12... Porous shielding plate.弗1庨Figure 4Figure 5Figure 2Figure 3Figure 6Figure 1C...c11! ! Medium honeycomb +1j2...porous shielding plate
Claims (1)
ング内の排気出口側に設けられた酸化触媒と、該酸化触
媒との間に所定の間隔を保持して排気の入口側に設けら
れた前置触媒とを有すると共に、前記前置触媒がディー
ゼルパティキュレートを常態では着火不可能な低い排気
温度において着火させ得る特性を有することを特徴とす
るディーゼルエンジン用排気浄化装置。An oxidation catalyst provided on the exhaust outlet side in a casing having an exhaust inlet and a purified exhaust outlet, and an oxidation catalyst provided on the exhaust inlet side with a predetermined distance maintained between the oxidation catalyst and the oxidation catalyst 1. An exhaust gas purification device for a diesel engine, characterized in that the precatalyst has a property of being able to ignite diesel particulates at a low exhaust temperature at which diesel particulates cannot normally be ignited.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63259419A JPH02108806A (en) | 1988-10-17 | 1988-10-17 | Exhaust gas purifying device for diesel engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63259419A JPH02108806A (en) | 1988-10-17 | 1988-10-17 | Exhaust gas purifying device for diesel engine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02108806A true JPH02108806A (en) | 1990-04-20 |
Family
ID=17333840
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63259419A Pending JPH02108806A (en) | 1988-10-17 | 1988-10-17 | Exhaust gas purifying device for diesel engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02108806A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04140410A (en) * | 1990-09-28 | 1992-05-14 | Hino Motors Ltd | Exhaust emission control device for diesel engine |
| JPH04295122A (en) * | 1991-03-26 | 1992-10-20 | Matsushita Electric Ind Co Ltd | Filter regeneration device for internal combustion engine |
| JP2001259363A (en) * | 2000-03-21 | 2001-09-25 | Meidensha Corp | Method and apparatus for treating exhaust gas |
| JP2001286725A (en) * | 2000-04-11 | 2001-10-16 | Meidensha Corp | Method and apparatus for treating exhaust gas |
| WO2002025072A1 (en) * | 2000-09-20 | 2002-03-28 | Toyota Jidosha Kabushiki Kaisha | Exhaust emission control filter and method of controlling exhaust emission |
| WO2002040836A1 (en) * | 2000-11-17 | 2002-05-23 | Toyota Jidosha Kabushiki Kaisha | Exhaust emission control device and method of controlling exhaust emission |
-
1988
- 1988-10-17 JP JP63259419A patent/JPH02108806A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04140410A (en) * | 1990-09-28 | 1992-05-14 | Hino Motors Ltd | Exhaust emission control device for diesel engine |
| JPH04295122A (en) * | 1991-03-26 | 1992-10-20 | Matsushita Electric Ind Co Ltd | Filter regeneration device for internal combustion engine |
| JP2001259363A (en) * | 2000-03-21 | 2001-09-25 | Meidensha Corp | Method and apparatus for treating exhaust gas |
| JP2001286725A (en) * | 2000-04-11 | 2001-10-16 | Meidensha Corp | Method and apparatus for treating exhaust gas |
| WO2002025072A1 (en) * | 2000-09-20 | 2002-03-28 | Toyota Jidosha Kabushiki Kaisha | Exhaust emission control filter and method of controlling exhaust emission |
| US6945036B2 (en) | 2000-09-20 | 2005-09-20 | Toyota Jidosha Kabushiki Kaisha | Exhaust emission control filter and method of controlling exhaust emission |
| WO2002040836A1 (en) * | 2000-11-17 | 2002-05-23 | Toyota Jidosha Kabushiki Kaisha | Exhaust emission control device and method of controlling exhaust emission |
| US6829891B2 (en) | 2000-11-17 | 2004-12-14 | Toyota Jidosha Kabushiki Kaisha | Exhaust emission control device and method of controlling exhaust emission |
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