JP2009243419A - Exhaust emission control device of internal combustion engine - Google Patents

Exhaust emission control device of internal combustion engine Download PDF

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JP2009243419A
JP2009243419A JP2008093530A JP2008093530A JP2009243419A JP 2009243419 A JP2009243419 A JP 2009243419A JP 2008093530 A JP2008093530 A JP 2008093530A JP 2008093530 A JP2008093530 A JP 2008093530A JP 2009243419 A JP2009243419 A JP 2009243419A
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exhaust
corona discharge
energy
internal combustion
combustion engine
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Masahiro Okajima
正博 岡嶋
Yoshiaki Nishijima
義明 西島
Masatoshi Kuroyanagi
正利 黒柳
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Denso Corp
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Denso Corp
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/01Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust by means of electric or electrostatic separators
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B03SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03CMAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/017Combinations of electrostatic separation with other processes, not otherwise provided for
    • B03C3/0175Amassing particles by electric fields, e.g. agglomeration
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B03SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03CMAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/02Plant or installations having external electricity supply
    • B03C3/04Plant or installations having external electricity supply dry type
    • B03C3/06Plant or installations having external electricity supply dry type characterised by presence of stationary tube electrodes
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B03SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03CMAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/02Plant or installations having external electricity supply
    • B03C3/04Plant or installations having external electricity supply dry type
    • B03C3/12Plant or installations having external electricity supply dry type characterised by separation of ionising and collecting stations
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B03SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03CMAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/34Constructional details or accessories or operation thereof
    • B03C3/40Electrode constructions
    • B03C3/41Ionising-electrodes
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B03SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03CMAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/34Constructional details or accessories or operation thereof
    • B03C3/40Electrode constructions
    • B03C3/45Collecting-electrodes
    • B03C3/49Collecting-electrodes tubular
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B03SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03CMAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C2201/00Details of magnetic or electrostatic separation
    • B03C2201/08Ionising electrode being a rod
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B03SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03CMAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C2201/00Details of magnetic or electrostatic separation
    • B03C2201/10Ionising electrode with two or more serrated ends or sides
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B03SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03CMAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C2201/00Details of magnetic or electrostatic separation
    • B03C2201/30Details of magnetic or electrostatic separation for use in or with vehicles
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2240/00Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
    • F01N2240/28Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being a plasma reactor
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00Road transport of goods or passengers
    • Y02T10/10Internal combustion engine [ICE] based vehicles
    • Y02T10/12Improving ICE efficiencies

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Processes For Solid Components From Exhaust (AREA)
  • Electrostatic Separation (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To prevent exhaust gas particulates from being discharged to the outside by processing the exhaust gas particulates included in exhaust gas of an internal combustion engine by utilizing corona discharge. <P>SOLUTION: The exhaust gas control device 1 is arranged with a corona discharge electrode 2 and a confronting electrode 3 in a cylindrical housing H connected with an exhaust gas flow passage 42 of the engine 41 and is provided with a corona discharge part for generating corona discharge by applying high voltage between both the electrodes 2, 3. The exhaust gas particulate is controlled by oxidation combustion by applying energy so large that the generation energy by the corona discharge excesses activation energy for oxidizing the exhaust particulate in the exhaust gas. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、内燃機関の排気ガスに含まれる排気微粒子をコロナ放電を利用して浄化する排気微粒子浄化装置に関する。   The present invention relates to an exhaust particulate purification device that purifies exhaust particulates contained in exhaust gas of an internal combustion engine using corona discharge.

ディーゼルエンジンやリーンバーンガソリンエンジンから排出される排気微粒子(PM)を処理するために、種々の装置が提案されている。その一例として、排気流路に多孔質セラミックスからなるパティキュレートフィルタを設置して、排気微粒子を捕集することが行われているが、粒子径がナノミクロン級と小さい微粒子(ナノ微粒子)が捕捉されずに通過してしまうおそれがある。一方、微粒子のすり抜けを防止するために、パティキュレートフィルタの目を細かくすると、排気流路の圧損が増大する不具合がある。   Various devices have been proposed for treating exhaust particulate (PM) emitted from diesel engines and lean burn gasoline engines. As an example, a particulate filter made of porous ceramics is installed in the exhaust channel to collect exhaust particulates. However, small particulates (nanoparticulates) with a particle size of nanomicron are captured. There is a risk of passing without being. On the other hand, if the particulate filter is narrowed to prevent the fine particles from slipping through, there is a problem that the pressure loss of the exhaust passage increases.

そこで、コロナ放電を利用して微粒子を静電凝集させる装置が検討されている。例えば、特許文献1には、排気流路の中央部に高電圧電極を、その外周に低電圧電極を配置し、コロナ放電を発生させて帯電した排気微粒子を外周側に移動させることにより、微粒子の空間密度分布が高い外周側と空間密度分布が低い中央部とに分流し、それぞれに適したフィルタを下流に配置して微粒子を捕集する装置が開示されている。
特開2005−76497号公報
Therefore, an apparatus that electrostatically aggregates fine particles using corona discharge has been studied. For example, in Patent Document 1, a high-voltage electrode is disposed at the center of an exhaust passage, and a low-voltage electrode is disposed on the outer periphery of the exhaust passage. An apparatus is disclosed in which fine particles are collected by diverting to a peripheral portion having a high spatial density distribution and a central portion having a low spatial density distribution, and disposing a filter suitable for each in the downstream.
JP 2005-76497 A

また、特許文献2には、排気流路内に放電電極と、導電網状の集塵電極を対向配設させた装置が開示されている。この装置は、集塵電極に放出された電荷がコイルを介して接地部に回収される構成となっており、排気微粒子の帯電状態が持続しやすいために、集電電極に未到達の微粒子との間でクーロン力が作用し、帯電した微粒子の凝集を促進させる。
特開2006−37899号公報
Further, Patent Document 2 discloses an apparatus in which a discharge electrode and a conductive mesh-shaped dust collecting electrode are disposed opposite to each other in an exhaust passage. This device is configured such that the electric charge discharged to the dust collection electrode is collected to the grounding part via the coil, and the charged state of the exhaust particulates is easily maintained. Coulomb force acts between them to promote the aggregation of charged fine particles.
JP 2006-37899 A

しかしながら、静電凝集した微粒子は結合力が弱いため、再分散する問題があった。特許文献1の装置では、高電圧電極の外周に配した低電圧電極に透過部を設け、静電凝集させた微粒子を、透過部の外側のフィルタにて捕集するようになっているが、排気流れがあるために、凝集微粒子がフィルタ内で衝突し再分散、離脱するおそれがある。   However, electrostatically agglomerated fine particles have a problem of redispersion because the bonding force is weak. In the apparatus of Patent Document 1, a low voltage electrode arranged on the outer periphery of the high voltage electrode is provided with a transmission part, and electrostatically aggregated fine particles are collected by a filter outside the transmission part. Since there is an exhaust flow, the aggregated particles may collide in the filter and re-disperse or leave.

特許文献2の構成でも、集塵電極で凝集した微粒子を捕集するために、下流にパティキュレートフィルタ(DPF)等が設置されるが、排ガスの流れが速いと、DPFのセル壁面への衝突により凝集微粒子が再分散し、セル壁をすり抜けてしまう。その場合、離脱した微粒子が捕集されずに、外部へ排出されるおそれがある。   Even in the configuration of Patent Document 2, a particulate filter (DPF) or the like is installed downstream to collect the fine particles aggregated by the dust collection electrode. As a result, the agglomerated fine particles are re-dispersed and pass through the cell walls. In that case, the separated fine particles may not be collected and discharged to the outside.

そこで、本発明の目的は、内燃機関の排気ガスに含まれる排気微粒子をコロナ放電を利用して処理し、排気微粒子が外部へ排出されるのを防止することができる排気微粒子浄化装置を提供することにある。   Accordingly, an object of the present invention is to provide an exhaust particulate purification device capable of treating exhaust particulate contained in exhaust gas of an internal combustion engine using corona discharge and preventing the exhaust particulate from being discharged to the outside. There is.

本発明請求項1の排気浄化装置は、内燃機関の排気流路の一部を構成する筒状容器内に、コロナ放電電極と対向電極とを配設し、両電極間に高電圧を印加してコロナ放電を発生させるコロナ放電部を備える。該コロナ放電部には、コロナ放電による発生エネルギが、排気中の排気微粒子を酸化するための活性化エネルギ以上となるエネルギを投入して、排気微粒子を酸化燃焼により浄化することを特徴とする。   In the exhaust emission control device according to the first aspect of the present invention, a corona discharge electrode and a counter electrode are disposed in a cylindrical container constituting a part of an exhaust passage of an internal combustion engine, and a high voltage is applied between both electrodes. A corona discharge unit for generating corona discharge. The corona discharge part is characterized in that the energy generated by the corona discharge is greater than the activation energy for oxidizing the exhaust particulates in the exhaust, and the exhaust particulates are purified by oxidative combustion.

コロナ放電による発生エネルギが、排気微粒子の酸化反応に必要な活性化エネルギを越えると、排気微粒子を構成する炭素が排気中の酸素と結合して二酸化炭素となる。すなわち、十分なエネルギを投入することで、ナノ微粒子を燃焼させて浄化することができ、ナノ微粒子のすり抜けや凝集微粒子の再分散・離脱による外部への放出を抑制して、高い浄化性能を実現することが可能となる。   When the energy generated by the corona discharge exceeds the activation energy necessary for the oxidation reaction of the exhaust particulates, the carbon constituting the exhaust particulates combines with the oxygen in the exhaust to become carbon dioxide. In other words, by applying sufficient energy, nanoparticles can be burned and purified, and high purification performance is achieved by suppressing the release of nanoparticles by passing through and the redispersion / detachment of aggregated particles. It becomes possible to do.

請求項2の発明において、上記コロナ放電部は、上記筒状容器の略中央部に配置される上記コロナ放電電極の放電部から、上記排気流路内に電子を放出させ、該放出電子が酸素と付着し酸素イオンとなって排気微粒子に衝突させて酸化エネルギを付与する。   In the invention of claim 2, the corona discharge part causes electrons to be emitted from the discharge part of the corona discharge electrode disposed at a substantially central part of the cylindrical container into the exhaust passage, and the emitted electrons are oxygenated. It adheres and becomes oxygen ions and collides with exhaust particulates to give oxidation energy.

具体的には、コロナ放電電極を排気流路の略中央部に配置し、導入される排気微粒子に向けて電子を効率よく放射させるのがよい。   Specifically, it is preferable that the corona discharge electrode is disposed at a substantially central portion of the exhaust flow path so that electrons are efficiently emitted toward the exhaust fine particles to be introduced.

請求項3の発明において、上記コロナ放電部へ投入されるエネルギを制御する制御部を設け、該制御部は、内燃機関にて発生する排気微粒子の量に応じて、上記コロナ放電電極への印加電圧を決定する。   According to a third aspect of the present invention, there is provided a control unit that controls energy input to the corona discharge unit, and the control unit applies to the corona discharge electrode according to the amount of exhaust particulates generated in the internal combustion engine. Determine the voltage.

具体的には、制御部にて、発生する排気微粒子を酸化するのに必要なエネルギを算出し、必要なエネルギを効率よく投入するのがよい。   Specifically, it is preferable that the control unit calculates the energy required to oxidize the generated exhaust particulates and efficiently inputs the necessary energy.

請求項4の発明において、上記コロナ放電部内または上記コロナ放電部の下流に、排気微粒子の捕集部を設け、上記コロナ放電部に投入されるエネルギの一部により排気微粒子の一部を帯電および凝集させて、上記捕集部に捕集する。   According to a fourth aspect of the present invention, an exhaust particulate collection unit is provided in the corona discharge part or downstream of the corona discharge part, and a part of the exhaust particulates are charged and charged by a part of energy input to the corona discharge part. Aggregate and collect in the collecting part.

排気微粒子の酸化による浄化に加えて、帯電・凝集による捕集を併用することもできる。この時、好適には、捕集部を設けて凝集微粒子を捕集することで、外部への排出を防止することができる。   In addition to purification by exhaust gas oxidation, collection by charging / aggregation can be used in combination. At this time, preferably, the collection part is provided to collect the aggregated fine particles, thereby preventing discharge to the outside.

請求項5の発明において、上記コロナ放電部は、上記筒状容器の内周面に沿って配置される中空メッシュ状の導電性筒壁部を上記対向電極とし、その内部空間を上記捕集部とする。   In the invention of claim 5, the corona discharge part has a hollow mesh conductive cylindrical wall part arranged along the inner peripheral surface of the cylindrical container as the counter electrode, and the internal space is the collecting part. And

具体的には、捕集部を中空メッシュ状の導電性筒壁部とし、対向電極を兼ねる構成とすることができる。   Specifically, the collecting part can be a hollow mesh conductive cylindrical wall part, which also serves as a counter electrode.

以下、本発明をディーゼルエンジンの排気浄化装置に適用した第1の実施形態を図面に基づいて説明する。図1(a)は、排気浄化装置1の全体構成を示し、図1(b)は、排気浄化装置1の排気管41への接続構造を示している。図中、排気浄化装置1は、エンジン41の排気管42に接続される筒状容器としてのハウジングH内に、コロナ放電電極2と対向電極となる接地電極3を配設してコロナ放電部を構成している。本実施形態では、コロナ放電電極2を取り囲むハウジングHの筒部を接地電位として、筒内壁を接地電極3として構成する。ハウジングHは排気管42より大径の円筒管状で、その内部は円形断面の排気流路11となり、両端小径部にて排気管の直線部に接続されるようになっている。   A first embodiment in which the present invention is applied to an exhaust emission control device for a diesel engine will be described below with reference to the drawings. FIG. 1A shows the overall configuration of the exhaust purification device 1, and FIG. 1B shows the connection structure of the exhaust purification device 1 to the exhaust pipe 41. In the figure, an exhaust purification device 1 includes a corona discharge electrode 2 and a ground electrode 3 that is a counter electrode disposed in a housing H as a cylindrical container connected to an exhaust pipe 42 of an engine 41 to provide a corona discharge portion. It is composed. In the present embodiment, the cylindrical portion of the housing H surrounding the corona discharge electrode 2 is configured as a ground potential, and the cylindrical inner wall is configured as the ground electrode 3. The housing H is a cylindrical tube having a diameter larger than that of the exhaust pipe 42, and the inside thereof becomes the exhaust passage 11 having a circular cross section, and is connected to the straight portion of the exhaust pipe at both end small diameter portions.

図1(a)において、コロナ放電電極2は、上半部がハウジングHの筒壁から外部(図の上方)に突出し、下半部がハウジングH内の排気流路11に位置している。ハウジングHには、上部筒壁に設けた開口部を閉鎖するように保持プレート12がボルト固定してあり、コロナ放電電極2はその碍子部23外周に設けた雄ねじ部が、保持プレート12に設けた雌ねじ部に螺合され、ナット13にて締付け固定される。   In FIG. 1A, the corona discharge electrode 2 has an upper half protruding from the cylindrical wall of the housing H to the outside (upward in the drawing), and a lower half positioned in the exhaust flow path 11 in the housing H. The holding plate 12 is bolted to the housing H so as to close the opening provided in the upper cylindrical wall, and the corona discharge electrode 2 is provided with a male screw portion provided on the outer periphery of the lever portion 23 on the holding plate 12. It is screwed into the female thread portion and is fastened and fixed with a nut 13.

コロナ放電電極2は、外周が碍子部23に保持される棒状の導電部21と、その先端(図の下端側)に設けられる放電部22とからなる。導電部21は、ハウジングH外に位置し碍子部23から突出する基端(図の上端側)が図示しない直流高電圧電源と接続され、先端側は碍子部23から露出してL字状に屈曲している。L字状の屈曲部は排気流路11の軸線に沿って延び、最先端の放電部22へ高電圧を導くようになっている。放電部22は、例えば略円盤状で、外周に放射状に設けた多数の突起を有する形状とする。このように、多数の突起を設けることで放電率を高めるとともに、排気流路11内に均等にコロナ放電を発生させて、浄化性能を高めることができる。   The corona discharge electrode 2 includes a rod-shaped conductive portion 21 whose outer periphery is held by the insulator portion 23, and a discharge portion 22 provided at the tip (lower end side in the figure). The conductive portion 21 is located outside the housing H and has a base end (upper end side in the figure) protruding from the insulator portion 23 connected to a DC high-voltage power source (not shown), and a distal end side exposed from the insulator portion 23 in an L shape. It is bent. The L-shaped bent portion extends along the axis of the exhaust passage 11 and guides a high voltage to the most advanced discharge portion 22. The discharge part 22 has, for example, a substantially disk shape and a shape having a large number of protrusions provided radially on the outer periphery. In this way, by providing a large number of protrusions, the discharge rate can be increased, and the corona discharge can be evenly generated in the exhaust passage 11 to improve the purification performance.

次に、本発明の排気浄化装置1による排気微粒子浄化のメカニズムについて説明する。図1(b)において、エンジン41で発生し排気管42へ放出される排気微粒子は、通常、0.01μmから数μm程度の粒径であり、通常のパティキュレートフィルタ(DPF)では捕捉できないナノ微粒子を含んでいる。排気浄化装置1には、コロナ放電電極2への通電を制御する制御部5が設けられており、コロナ放電電極2の導電部21に直流高電圧電源から負の直流高電圧を印加すると、放電部22先端の突起近傍においてコロナ放電が発生する。図中に1)〜3)として示すように、この時、コロナ放電により放射される電子は高いエネルギを有しており、酸素に付着して酸素イオンとなって排気流路11内の排気微粒子(図中ナノPM)に衝突して反応させる。   Next, the mechanism of exhaust particulate purification by the exhaust purification apparatus 1 of the present invention will be described. In FIG. 1 (b), the exhaust particulates generated by the engine 41 and discharged to the exhaust pipe 42 usually have a particle size of about 0.01 μm to several μm and cannot be captured by a normal particulate filter (DPF). Contains fine particles. The exhaust purification device 1 is provided with a control unit 5 that controls energization to the corona discharge electrode 2. When a negative DC high voltage is applied from the DC high voltage power source to the conductive unit 21 of the corona discharge electrode 2, discharge is performed. Corona discharge occurs near the protrusion at the tip of the portion 22. At this time, as shown as 1) to 3) in the figure, the electrons emitted by the corona discharge have high energy, adhere to oxygen and become oxygen ions, and exhaust particulates in the exhaust passage 11. It collides with (nano PM in the figure) and reacts.

これを図1(c)に示すと、反応物質である排気微粒子(C)および酸素分子(O2 )に、コロナ放電による発生エネルギが付与されて、活性化状態となる。すなわち、酸化反応を生起するのに必要な活性化エネルギを越えるために、排気微粒子(C)および酸素イオン(O2 )が反応して二酸化炭素(CO2 )を生成することができる。本発明では、ナノ微粒子を気体分子である二酸化炭素(CO2 )に直接変化させるので、コロナ放電の発生エネルギを効果的に利用して、ナノ微粒子を浄化することができる。 When shown in this FIG. 1 (c), the reactants are as exhaust particles (C) and oxygen molecules (O 2), generating energy by corona discharge is applied, the activation state. That is, in order to exceed the activation energy required to cause the oxidation reaction, the exhaust particulates (C) and oxygen ions (O 2 ) can react to generate carbon dioxide (CO 2 ). In the present invention, since the nanoparticle is directly changed to carbon dioxide (CO 2 ) which is a gas molecule, the nanoparticle can be purified by effectively using the energy generated by corona discharge.

制御部5は、コロナ放電電極2へ投入されるエネルギを制御する。コロナ放電部へ投入されるエネルギは、エンジン41にて発生する排気微粒子の量に応じて決定され、排気浄化装置1に導入される排気微粒子を酸化燃焼させるのに必要なエネルギを、コロナ放電によって発生させる。図2は、発生する排気微粒子の量(発生PM量:g/hr)とPM燃焼させるのに必要なエネルギ(E:kJ/hr)の関係を示すグラフで、例えば、排気管42に排出されるPM量がM0 であるとすると、M0 に相当する炭素を活性化して酸化するための必要エネルギE0 以上、コロナ放電での発生エネルギがあればよいことがわかる。   The controller 5 controls energy input to the corona discharge electrode 2. The energy input to the corona discharge unit is determined according to the amount of exhaust particulate generated in the engine 41, and the energy necessary for oxidizing and combusting the exhaust particulate introduced into the exhaust purification device 1 is determined by corona discharge. generate. FIG. 2 is a graph showing the relationship between the amount of generated exhaust particulates (generated PM amount: g / hr) and the energy required for PM combustion (E: kJ / hr). For example, the graph is discharged to the exhaust pipe 42. Assuming that the amount of PM to be generated is M0, it is understood that the energy generated by corona discharge should be greater than the required energy E0 for activating and oxidizing the carbon corresponding to M0.

ここで、PM燃焼に必要なエネルギEは、下記式(1)を用いて算出される。
E=(M/m)・Ea・・・(1)
・捕集PM燃焼のための必要エネルギ :E(kJ/hr)
・捕集PM重量 :M(g/hr)
・炭素分子量 :m(=12)
・活性化エネルギ:Ea(=236kJ/mol)
一方、コロナ放電での発生エネルギEcは、下記式(2)を用いて算出される。
Ec=Ev・Ia・t・・・(2)
・供給電圧 :Ev(kV)
・電流 :Ia(A)
・時間 :t(s)
Here, the energy E required for PM combustion is calculated using the following equation (1).
E = (M / m) · Ea (1)
・ Necessary energy for collected PM combustion: E (kJ / hr)
-Collected PM weight: M (g / hr)
Carbon molecular weight: m (= 12)
Activation energy: Ea (= 236 kJ / mol)
On the other hand, the generated energy Ec in the corona discharge is calculated using the following formula (2).
Ec = Ev · Ia · t (2)
・ Supply voltage: Ev (kV)
-Current: Ia (A)
・ Time: t (s)

式(1)より、例えばM0 =1.2(g/hr) とすると、PM燃焼に必要なエネルギE=24(kJ/hr)であるから、E0 ≧24(kJ/hr)の発生エネルギがあれば、酸化燃焼による排気微粒子の浄化が可能である。また式(2)より、E0 =Ec≧24(kJ/hr)が成立するには、例えば、下記式(3)のように供給電圧と電流を設定すればよい。
Ec=Ev・Ia・t
=13×0.5×10-3×602 =24(kJ/hr)・・・・・・(3)
すなわち電流Ia=0.5(mA) の時、導電部21に直流高電圧電源から印加される負の直流高電圧が、Ev=−13(kV) 以上であれば、活性化エネルギ以上となる。
From equation (1), for example, if M0 = 1.2 (g / hr), the energy required for PM combustion is E = 24 (kJ / hr), so that the generated energy of E0 ≧ 24 (kJ / hr) is If so, exhaust particulates can be purified by oxidation combustion. In order to establish E0 = Ec ≧ 24 (kJ / hr) from the equation (2), for example, the supply voltage and current may be set as in the following equation (3).
Ec = Ev · Ia · t
= 13 × 0.5 × 10 −3 × 60 2 = 24 (kJ / hr) (3)
That is, when the current Ia = 0.5 (mA), if the negative DC high voltage applied to the conductive portion 21 from the DC high voltage power supply is Ev = −13 (kV) or more, the activation energy or more is reached. .

この時、排気微粒子の濃度が高いコロナ放電部の略中央部にコロナ放電電極2を配置して、効率よい浄化を図っているが、実際には、コロナ放電部内の排気微粒子分布等により、発生エネルギのロスが生じる。このため、好適には、発生エネルギのロス分を考慮して、例えば1.5倍以上のエネルギ(E1 =1.5×E0 )を投入するのがよい。従って、式(1)、(2)より、例えばM0 =1.2(g/hr) 、電流Ia=0.5(mA) の場合、E1 ≧36(kJ/hr)の発生エネルギがあればよく、このための印加電圧Ev=−20(kV) 以上であれば、十分な浄化性能が得られる。   At this time, the corona discharge electrode 2 is arranged at the substantially central portion of the corona discharge portion where the concentration of exhaust particulates is high for efficient purification. However, in actuality, it is generated due to the exhaust particulate distribution in the corona discharge portion. Energy loss occurs. For this reason, it is preferable to input, for example, 1.5 times or more energy (E1 = 1.5 × E0) in consideration of the loss of generated energy. Therefore, from equations (1) and (2), for example, if M0 = 1.2 (g / hr) and current Ia = 0.5 (mA), if there is generated energy of E1 ≥36 (kJ / hr) If the applied voltage Ev for this is equal to or higher than −20 (kV), sufficient purification performance can be obtained.

このように、本発明では、制御部5による投入エネルギを、発生する排気微粒子の量に応じて変更し、燃焼に必要なエネルギを発生させるので、より効果的に排気微粒子を浄化することができる。その具体的な制御の一例を図3のフローチャートに示すと、まず、ステップ1において、エンジン41の負荷および回転数情報を取り込み、ステップ2において、これら情報を用いてエンジン41で発生する排気微粒子の量(PM量M:g/hr) を算出する。PM量Mは、例えば、予め実験を行って負荷および回転数と排気微粒子の発生量の関係を求め、マップとして制御部5に記憶しておくことができる。   In this way, in the present invention, the input energy by the control unit 5 is changed according to the amount of exhaust particulates to be generated and the energy required for combustion is generated, so that the exhaust particulates can be purified more effectively. . An example of the specific control is shown in the flowchart of FIG. 3. First, in step 1, the load and rotation speed information of the engine 41 is fetched, and in step 2, the exhaust particulates generated in the engine 41 using these information. The amount (PM amount M: g / hr) is calculated. The PM amount M can be stored in the control unit 5 as a map, for example, by conducting an experiment in advance to obtain the relationship between the load and the rotational speed and the amount of exhaust particulate generation.

ステップ3では、ステップ2において算出したPM量Mが0以上(PM量M>0)であるかどうかを判定する。ステップ2が肯定判定された場合には、ステップ4へ進み、否定判定された場合には、ステップ1に戻る。これは、例えば高負荷時のようにエンジン41の燃焼効率が高く排気微粒子の発生がほとんどない場合、または排気温度が高く、発生した排気微粒子が自然燃焼するような運転状態においては、排気浄化装置1を作動させる必要がないと判断されるためで、コロナ放電部へ通電しないことで、エネルギロスを避けることができる。   In step 3, it is determined whether the PM amount M calculated in step 2 is 0 or more (PM amount M> 0). If a positive determination is made in step 2, the process proceeds to step 4. If a negative determination is made, the process returns to step 1. This is because, for example, when the combustion efficiency of the engine 41 is high and almost no exhaust particulates are generated, such as during a high load, or in an operating state in which the exhaust temperature is high and the generated exhaust particulates spontaneously combust, Since it is judged that it is not necessary to operate 1, energy loss can be avoided by not energizing the corona discharge part.

ステップ4では、上記式(1)、(2)および図2の関係を用いて、ステップ2において算出したPM量M(g/hr) を酸化するための必要エネルギE1 を算出し、コロナ放電電極2への供給電圧Evを決定する。続くステップ5で、コロナ放電電極2へ直流高電圧電源から所定の電圧Evを印加し、ステップ1へ戻る。このようにして、エンジンの運転状態に応じた供給電圧Evを印加し、コロナ放電を発生させて排気微粒子を浄化することができる。   In step 4, the necessary energy E1 for oxidizing the PM amount M (g / hr) calculated in step 2 is calculated by using the relations of the above equations (1), (2) and FIG. The supply voltage Ev to 2 is determined. In the subsequent step 5, a predetermined voltage Ev is applied from the DC high voltage power source to the corona discharge electrode 2, and the process returns to step 1. In this way, it is possible to purify the exhaust particulates by applying the supply voltage Ev according to the operating state of the engine and generating corona discharge.

図4は、本発明の排気浄化装置1による効果を確認するために行った評価試験結果である。図4(a)は、評価装置構成を示す図で、PM発生装置6から排出される排気微粒子とエアボンベ7からのエアを、排気浄化装置1に導入してコロナ放電を発生させ、その下流に配設したCO2 計8で、CO2 濃度の変化を調べた。CO2 計8は、ppmオーダの低濃度CO2 を計測するもので、評価条件を常温とする必要があることから、実車エンジンでなくPM発生装置6を用いて同等の排気微粒子を発生させた。排気微粒子の発生量Qp=3.9g/min.、エア流量=7.6L/min.とし、排気浄化装置1に上記図2、3に示した方法で算出した必要エネルギを投入した場合に、排気浄化装置1から排出される排気中のCO2 濃度変化を図4(b)に示した。 FIG. 4 shows the results of an evaluation test conducted to confirm the effect of the exhaust emission control device 1 of the present invention. FIG. 4A is a diagram showing the configuration of the evaluation apparatus, in which exhaust particulates discharged from the PM generator 6 and air from the air cylinder 7 are introduced into the exhaust purification apparatus 1 to generate a corona discharge, and downstream thereof. A change in CO 2 concentration was examined with the installed CO 2 meter 8. The CO 2 meter 8 measures low-concentration CO 2 in the order of ppm, and since it is necessary to set the evaluation condition to room temperature, equivalent exhaust particulates were generated using the PM generator 6 instead of the actual vehicle engine. . Exhaust particulate generation amount Qp = 3.9 g / min. , Air flow rate = 7.6 L / min. FIG. 4B shows the change in CO 2 concentration in the exhaust discharged from the exhaust purification device 1 when the required energy calculated by the method shown in FIGS. It was.

図4(b)に示されるように、排気浄化装置1の作動を開始した時点より、排気中のCO2 濃度が急増しており、コロナ放電電極2への電圧印加によってコロナ放電が発生し、排気微粒子の酸化反応が生じてCO2 が生成したことが確認された。排気浄化装置1は、作動を継続している間、CO2 濃度が高い状態にあり、作動を停止した時点から徐々に減少して、初期濃度に戻った。 As shown in FIG. 4 (b), the CO 2 concentration in the exhaust gas has increased rapidly since the start of the operation of the exhaust gas purification device 1, and a corona discharge is generated by applying a voltage to the corona discharge electrode 2. It was confirmed that an oxidation reaction of exhaust particulates occurred and CO 2 was generated. The exhaust gas purification device 1 was in a state where the CO 2 concentration was high while continuing the operation, and gradually decreased from the time when the operation was stopped, and returned to the initial concentration.

図5に本発明の第2の実施形態を示す。本実施形態の排気浄化装置1は、コロナ放電エネルギを用いた排気微粒子の酸化反応による浄化と、排気微粒子の帯電による凝集を併用するものである。排気浄化装置1の接地電極3は、集塵電極を兼ねており、凝集微粒子を保持する機能を有する。その他の装置構成は、上記第1の実施形態と同様であり、説明を省略する。   FIG. 5 shows a second embodiment of the present invention. The exhaust purification apparatus 1 of the present embodiment uses both purification by exhaust gas oxidation reaction using corona discharge energy and aggregation of exhaust fine particles by charging. The ground electrode 3 of the exhaust emission control device 1 also serves as a dust collection electrode and has a function of holding aggregated fine particles. Other apparatus configurations are the same as those in the first embodiment, and a description thereof will be omitted.

上述した図3に基づく制御では、発生する排気微粒子が多くなるほど、酸化に必要なエネルギが増加する。このために、例えば、バッテリ電圧が低下している状態では、排気微粒子の量に応じた十分なエネルギが投入できず、活性化エネルギ不足となるおそれがある。そこで本実施形態では、排気微粒子の量とバッテリ電圧に応じて、投入可能なエネルギを決定し、発生する排気微粒子の全部を酸化反応させず、一部は帯電凝集させて捕集する。この場合、コロナ放電が発生して電子が放射されると、その一部は電子親和性の高い気体分子(酸素)をマイナスイオン化し、付近の排気微粒子(図中ナノPM)に付着してこれを負に帯電させる(図中1)〜2))。帯電した排気微粒子(ナノPM)は、クーロン力によって集塵電極を兼ねる接地電極3に引き寄せられ、下流へ向かうガス流から徐々に離脱して、凝集しながら外周側へ移動する。凝集した排気微粒子が、接地電極3に達すると、放電し、凝集保持される(図中3)〜5))。   In the control based on FIG. 3 described above, the energy required for oxidation increases as more exhaust particulates are generated. For this reason, for example, in a state where the battery voltage is low, sufficient energy corresponding to the amount of exhaust particulates cannot be input, and activation energy may be insufficient. Therefore, in the present embodiment, the energy that can be input is determined according to the amount of exhaust particulates and the battery voltage, and all of the generated exhaust particulates are not subjected to an oxidation reaction, but a part of them are charged and aggregated and collected. In this case, when corona discharge occurs and electrons are emitted, some of them negatively ionize gas molecules (oxygen) with high electron affinity and adhere to the nearby exhaust particles (nano PM in the figure). Is negatively charged (1) to 2)). The charged exhaust particulates (nano PM) are attracted to the ground electrode 3 also serving as a dust collecting electrode by the Coulomb force, gradually depart from the gas flow toward the downstream, and move to the outer peripheral side while aggregating. When the agglomerated exhaust particulates reach the ground electrode 3, they are discharged and agglomerated and held (in the figure, 3) to 5)).

図6に示すように、排気微粒子の浄化手法は、発生する排気微粒子の量(PM重量)と投入エネルギによって決まる。排気微粒子の酸化反応による浄化をCO2 領域、排気微粒子の帯電による凝集を帯電捕集領域とすると、PM重量が少なく投入エネルギが多い領域は、CO2 領域となり、PM重量が多く投入エネルギが少ない領域は、帯電捕集領域となる。これらの中間領域は、CO2 領域+帯電捕集領域となる。このように、投入可能なエネルギに応じて、酸化反応による浄化に、帯電捕集を組み合わせることで、エネルギを効率よく利用して、排気微粒子を浄化可能である。 As shown in FIG. 6, the exhaust particulate purification method is determined by the amount of exhaust particulate generated (PM weight) and the input energy. If the purification by exhaust gas oxidation reaction is the CO 2 region, and the aggregation by exhaust gas charging is the charge collection region, the region where the PM weight is low and the input energy is high is the CO 2 region, the PM weight is high and the input energy is low. The region becomes a charge collection region. These intermediate regions are CO 2 region + charge collection region. In this manner, exhaust particulates can be purified by efficiently using energy by combining electrification collection with purification by oxidation reaction according to the energy that can be input.

図7は、本実施形態の排気浄化装置1において、コロナ放電電極2への電圧印加による排気微粒子の凝集現象を検証した結果である。図7(a)は、印加電圧0V、すなわち、コロナ放電を発生させない状態で、排気浄化装置1の集塵電極を兼ねる接地電極3付近に付着する微粒子の粒径分布を、図7(b)は、印加電圧−10Vとした時の、接地電極3付近に付着した微粒子の粒径分布を、それぞれ示すものである。図7(a)は、粒径分布のピークが1μm以下にあり、エンジンから排出されたままの標準粒子が、主に1μm以下の極微小粒子の集合体であることがわかる。これに対し、図7(b)では、1μm以下のピークがなくなり、5〜10μmの粗大粒子の重量が増加しており、コロナ放電の発生エネルギにより微粒子の帯電・凝集が生じたことが確認された。   FIG. 7 shows the result of verifying the agglomeration phenomenon of exhaust particulates due to voltage application to the corona discharge electrode 2 in the exhaust purification device 1 of the present embodiment. FIG. 7A shows the particle size distribution of fine particles adhering to the vicinity of the ground electrode 3 that also serves as the dust collection electrode of the exhaust purification apparatus 1 in the state where the applied voltage is 0 V, ie, no corona discharge is generated. These show the particle size distribution of the fine particles adhering to the vicinity of the ground electrode 3 when the applied voltage is −10 V, respectively. FIG. 7A shows that the peak of the particle size distribution is 1 μm or less, and the standard particles that are discharged from the engine are mainly aggregates of ultrafine particles of 1 μm or less. On the other hand, in FIG. 7B, the peak of 1 μm or less disappeared, the weight of coarse particles of 5 to 10 μm increased, and it was confirmed that charging and aggregation of fine particles occurred due to the energy generated by corona discharge. It was.

図8は、本実施形態の制御部5による制御の一例を示すものである。まず、ステップ11において、エンジン41の負荷および回転数情報を取り込み、ステップ12において、これら情報を用いてエンジン41で発生する排気微粒子の量(PM量M:g/hr) を算出する。PM量Mは、例えば、予め実験を行って負荷および回転数と排気微粒子の発生量の関係を求め、マップとして制御部5に記憶しておくことができる。   FIG. 8 shows an example of control by the control unit 5 of the present embodiment. First, in step 11, load and rotation speed information of the engine 41 is taken, and in step 12, the amount of exhaust particulates (PM amount M: g / hr) generated in the engine 41 is calculated using these information. The PM amount M can be stored in the control unit 5 as a map, for example, by conducting an experiment in advance to obtain the relationship between the load and the rotational speed and the amount of exhaust particulate generation.

ステップ13では、ステップ12において算出したPM量Mが0以上(PM量M>0)であるかどうかを判定する。ステップ12が肯定判定された場合には、ステップ14へ進み、否定判定された場合には、ステップ11に戻る。ステップ14では、バッテリ電圧情報を取り込み、この情報を基に、ステップ15で、投入可能な発生エネルギを算出する。これは、バッテリ電圧が低い状態では、算出したPM量M(g/hr) を酸化するための必要エネルギE1 を供給できない場合があるためで、まず投入可能なエネルギを設定することで、効率よく排気微粒子を浄化する。   In step 13, it is determined whether the PM amount M calculated in step 12 is 0 or more (PM amount M> 0). If an affirmative determination is made in step 12, the process proceeds to step 14, and if a negative determination is made, the process returns to step 11. In step 14, the battery voltage information is taken in, and based on this information, the generated energy that can be input is calculated in step 15. This is because the necessary energy E1 for oxidizing the calculated PM amount M (g / hr) may not be supplied in a state where the battery voltage is low. Purifies exhaust particulates.

ステップ16では、算出したPM量Mおよび投入可能な発生エネルギと、上記図6の関係を用いて、浄化手法を決定する。浄化手法は、排気微粒子の酸化反応による浄化(CO2 領域)、排気微粒子の帯電による凝集(帯電捕集領域CO2 領域)、またはこれらの組み合わせとなる。次いで、ステップ17で、投入可能な発生エネルギに対応する電圧を印加し、コロナ放電エネルギを投入する。 In step 16, the purification method is determined using the calculated PM amount M, the generated energy that can be input, and the relationship shown in FIG. The purification method is purification by exhaust gas oxidation reaction (CO 2 region), aggregation by charging of exhaust particulates (charge collection region CO 2 region), or a combination thereof. Next, in step 17, a voltage corresponding to the generated energy that can be input is applied, and corona discharge energy is input.

さらに、ステップ18では、帯電凝集した排気微粒子の捕集量Mc(累積値)を算出し、ステップ19で、捕集量Mcが捕集許容値を越えているか否か(Mc>捕集許容値)を判定する。ステップ19が否定判定されると、ステップ17に戻り、肯定判定されるとステップ20へ進んで、運転者へのアラーム(警告)手段を作動させる。このように、酸化燃焼による排気微粒子の浄化手法に加えて、帯電凝集による捕集手法を適宜組み合わせることで、発生エネルギを有効利用して効果的に排気微粒子を浄化することができる。   Further, in step 18, the collection amount Mc (cumulative value) of the charged and agglomerated exhaust particulates is calculated, and in step 19, whether or not the collection amount Mc exceeds the collection allowable value (Mc> collection allowable value). ). If a negative determination is made in step 19, the process returns to step 17, and if an affirmative determination is made, the process proceeds to step 20 to activate an alarm (warning) means for the driver. Thus, in addition to the purification method of exhaust particulates by oxidative combustion, the exhaust particulates can be effectively purified by effectively using generated energy by appropriately combining the collection method by charge aggregation.

図9に本発明の第3の実施形態を示す。本実施形態の排気浄化装置1は、上記図5の第2の実施形態の構成を基本とし、さらに捕集部に設けて、帯電凝集した排気微粒子を捕集可能としたものである。図9のように、本実施形態において、排気浄化装置1のハウジングHは、コロナ放電電極2の下流側を拡径した形状を有し、接地電極3となる拡径部の内周に沿って、中空メッシュ状の導電性筒状体よりなる捕集部31を設けている。捕集部31は、筒内を排気流路11としており、排気流路11に開口する多数の通孔を有する構成となっている。その他の構成は上記第2の実施形態と同様であり、説明を省略する。   FIG. 9 shows a third embodiment of the present invention. The exhaust emission control device 1 of the present embodiment is based on the configuration of the second embodiment of FIG. 5 described above, and is further provided in the collection unit so that the charged and aggregated exhaust particulates can be collected. As shown in FIG. 9, in the present embodiment, the housing H of the exhaust purification device 1 has a shape in which the diameter of the downstream side of the corona discharge electrode 2 is expanded, and along the inner periphery of the expanded portion that becomes the ground electrode 3. The collection part 31 which consists of a hollow mesh conductive cylinder is provided. The collection unit 31 has an exhaust passage 11 inside the cylinder, and has a large number of through holes that open into the exhaust passage 11. Other configurations are the same as those in the second embodiment, and a description thereof will be omitted.

本実施形態においても、酸化燃焼による排気微粒子の浄化と、帯電凝集による捕集を組み合わせることで、排気浄化装置1内に、コロナ放電による帯電微粒子が発生する(図中1)〜2))。この帯電微粒子が、クーロン力によって集塵電極を兼ねる接地電極3に引き寄せられ、外周側へ移動して、排気流路11に開口する多数の通孔から、捕集部31内に侵入する。帯電微粒子は、さらに捕集部31の奥へ移動し、電子を放出した後、凝集・保持される(図中3)〜5))。   Also in the present embodiment, by combining exhaust particulate purification by oxidative combustion and collection by charge aggregation, charged particulate by corona discharge is generated in the exhaust purification apparatus 1 (1 to 2) in the figure). The charged fine particles are attracted by the Coulomb force to the ground electrode 3 that also serves as a dust collecting electrode, move to the outer peripheral side, and enter the collecting portion 31 from a large number of through holes that open in the exhaust passage 11. The charged fine particles are further moved to the back of the collection unit 31 and emitted and then aggregated and held (3) to 5)).

このように、排気浄化装置1の外周に捕集部31を設けて、フィルタ機能を持たせることで、帯電凝集した排気微粒子が再分散するのを防止する効果が得られる。   As described above, by providing the collection unit 31 on the outer periphery of the exhaust gas purification apparatus 1 to have a filter function, an effect of preventing re-dispersion of the charged and aggregated exhaust particulates can be obtained.

捕集部31を構成する中空メッシュ状の導電性筒状体は、通常、1μmから10μm程度の粒径となる粗大粒子の流入を妨げない程度の大きさを有し、かつ内部に凝集微粒子を保持する十分な空間を有することが望ましい。通孔の大きさや形状、深さを適宜調整して、所望の捕集効果が得られるようにするとよい。   The hollow mesh conductive cylindrical body constituting the collecting part 31 usually has a size that does not hinder the inflow of coarse particles having a particle size of about 1 μm to 10 μm, and contains aggregated fine particles inside. It is desirable to have sufficient space to hold. It is preferable to adjust the size, shape, and depth of the through holes as appropriate so that a desired collection effect can be obtained.

以上のように、本発明によれば、ディーゼルエンジンやガソリンリーンバーンエンジンから排出される排気微粒子を酸化燃焼により浄化し、さらに帯電凝集による捕集やフィルタ機能を組み合わせることで、外部への放出を抑制することができる。よって、コロナ放電を用いて、浄化性能に優れ、高効率で低圧損の排気浄化装置を実現することができる。   As described above, according to the present invention, exhaust particulate discharged from a diesel engine or gasoline lean burn engine is purified by oxidation combustion, and further, collection by agglomeration and filter function are combined to release to the outside. Can be suppressed. Therefore, by using corona discharge, it is possible to realize an exhaust purification device that has excellent purification performance, high efficiency, and low pressure loss.

(a)は本発明の第1の実施形態における排気浄化装置の全体概略構成図、(b)は第1の実施形態の作動を説明するための図であり、(c)は排気微粒子の浄化のメカニズムを説明するための図である。(A) is the whole schematic block diagram of the exhaust emission control device in the first embodiment of the present invention, (b) is a diagram for explaining the operation of the first embodiment, (c) is the purification of exhaust particulates It is a figure for demonstrating the mechanism of. 発生PM量とPM燃焼のための必要エネルギの関係を示す図である。It is a figure which shows the relationship between the amount of generated PM and the required energy for PM combustion. 第1の実施形態における投入エネルギ制御のフローチャートである。It is a flowchart of the input energy control in 1st Embodiment. (a)は第1の実施形態の効果を確認するための評価装置構成図、(b)は評価結果を示す図である。(A) is an evaluation apparatus block diagram for confirming the effect of 1st Embodiment, (b) is a figure which shows an evaluation result. 本発明の第2の実施形態における排気浄化装置の全体概略構成図である。It is a whole schematic block diagram of the exhaust gas purification device in the 2nd Embodiment of this invention. 第2の実施形態におけるPM浄化手法を説明するための図である。It is a figure for demonstrating the PM purification method in 2nd Embodiment. (a)、(b)は第2の実施形態の効果を説明するための図である。(A), (b) is a figure for demonstrating the effect of 2nd Embodiment. 第2の実施形態における投入エネルギ制御のフローチャートである。It is a flowchart of the input energy control in 2nd Embodiment. 本発明の第3の実施形態における排気浄化装置の全体概略構成図である。It is a whole schematic block diagram of the exhaust gas purification apparatus in the 3rd Embodiment of this invention.

符号の説明Explanation of symbols

1 排気浄化装置
11 排気流路
2 コロナ放電電極
21 導電部
22 放電部
23 碍子部
3 接地電極(対向電極)
31 捕集部
4 エンジン
41 排気管
5 制御部
DESCRIPTION OF SYMBOLS 1 Exhaust purification device 11 Exhaust flow path 2 Corona discharge electrode 21 Conductive part 22 Discharge part 23 Insulator part 3 Ground electrode (counter electrode)
31 Collection part 4 Engine 41 Exhaust pipe 5 Control part

Claims (5)

内燃機関の排気流路の一部を構成する筒状容器内に、コロナ放電電極と対向電極とを配設し、両電極間に高電圧を印加してコロナ放電を発生させるコロナ放電部を備え、該コロナ放電部には、コロナ放電による発生エネルギが、排気中の排気微粒子を酸化するための活性化エネルギ以上となるエネルギを投入して、排気微粒子を酸化燃焼により浄化することを特徴とする内燃機関の排気浄化装置。   A corona discharge electrode and a counter electrode are disposed in a cylindrical vessel that constitutes a part of an exhaust flow path of an internal combustion engine, and a corona discharge unit that generates a corona discharge by applying a high voltage between the electrodes is provided. The corona discharge part is characterized in that the energy generated by the corona discharge is greater than the activation energy for oxidizing the exhaust particulates in the exhaust, and the exhaust particulates are purified by oxidative combustion. An exhaust purification device for an internal combustion engine. 上記コロナ放電部は、上記筒状容器の略中央部に配置される上記コロナ放電電極の放電部から、上記排気流路内に電子を放出させ、該放出電子を排気微粒子に衝突させて酸化エネルギを付与する請求項1記載の内燃機関の排気浄化装置。   The corona discharge part emits electrons into the exhaust flow path from the discharge part of the corona discharge electrode disposed at a substantially central part of the cylindrical container, and the emitted electrons collide with exhaust particulates to oxidize energy. The exhaust emission control device for an internal combustion engine according to claim 1, wherein 上記コロナ放電部へ投入されるエネルギを制御する制御部を設け、該制御部は、内燃機関にて発生する排気微粒子の量に応じて、上記コロナ放電電極への印加電圧を決定する請求項1または2記載の内燃機関の排気浄化装置。   2. A control unit for controlling energy input to the corona discharge unit is provided, and the control unit determines an applied voltage to the corona discharge electrode according to an amount of exhaust particulates generated in an internal combustion engine. Or the exhaust gas purifying device for an internal combustion engine according to 2 above. 上記コロナ放電部内または上記コロナ放電部の下流に、排気微粒子の捕集部を設け、上記コロナ放電部に投入されるエネルギの一部により排気微粒子の一部を帯電および凝集させて、上記捕集部に捕集する請求項1ないし3のいずれか記載の内燃機関の排気浄化装置。   An exhaust particulate collection part is provided in the corona discharge part or downstream of the corona discharge part, and a part of the exhaust particulates is charged and aggregated by a part of the energy input to the corona discharge part. The exhaust emission control device for an internal combustion engine according to any one of claims 1 to 3, wherein the exhaust gas purification device is collected in a portion. 上記コロナ放電部は、上記筒状容器の内周面に沿って配置される中空メッシュ状の導電性筒壁部を上記対向電極とし、その内部空間を上記捕集部とする請求項1ないし4のいずれか記載の内燃機関の排気浄化装置。   5. The corona discharge part has a hollow mesh conductive cylindrical wall part disposed along an inner peripheral surface of the cylindrical container as the counter electrode, and an internal space as the collecting part. An exhaust emission control device for an internal combustion engine according to any one of the above.
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