WO1997030274A1 - Device for the cleaning of exhaust gases from internal combustion engines - Google Patents

Device for the cleaning of exhaust gases from internal combustion engines Download PDF

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Publication number
WO1997030274A1
WO1997030274A1 PCT/AT1997/000024 AT9700024W WO9730274A1 WO 1997030274 A1 WO1997030274 A1 WO 1997030274A1 AT 9700024 W AT9700024 W AT 9700024W WO 9730274 A1 WO9730274 A1 WO 9730274A1
Authority
WO
WIPO (PCT)
Prior art keywords
electrode
ceramic
ceramic body
discharge electrode
exhaust gas
Prior art date
Application number
PCT/AT1997/000024
Other languages
German (de)
French (fr)
Inventor
Carl Maria Fleck
Original Assignee
Fleck Carl M
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Fleck Carl M filed Critical Fleck Carl M
Priority to DE59700888T priority Critical patent/DE59700888D1/en
Priority to AT97904288T priority patent/ATE188015T1/en
Priority to AU17119/97A priority patent/AU1711997A/en
Priority to EP97904288A priority patent/EP0880642B1/en
Priority to PL97328241A priority patent/PL328241A1/en
Priority to JP52881497A priority patent/JP4005137B2/en
Priority to BR9707497-7A priority patent/BR9707497A/en
Publication of WO1997030274A1 publication Critical patent/WO1997030274A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION 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
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/34—Constructional details or accessories or operation thereof
    • B03C3/40—Electrode constructions
    • B03C3/60—Use of special materials other than liquids
    • B03C3/62—Use of special materials other than liquids ceramics
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION 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
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/34—Constructional details or accessories or operation thereof
    • B03C3/66—Applications of electricity supply techniques
    • B03C3/70—Applications of electricity supply techniques insulating in electric separators
    • 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
    • F01N3/01—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust by means of electric or electrostatic separators
    • 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
    • F01N3/0217—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 the filtering elements having the form of hollow cylindrical bodies
    • 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
    • F01N3/027—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 electric or magnetic heating means
    • F01N3/0275—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 electric or magnetic heating means using electric discharge means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION 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
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C2201/00—Details of magnetic or electrostatic separation
    • B03C2201/12—Cleaning the device by burning the trapped particles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION 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
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C2201/00—Details of magnetic or electrostatic separation
    • B03C2201/30—Details of magnetic or electrostatic separation for use in or with vehicles
    • 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
    • F01N2330/00—Structure of catalyst support or particle filter
    • F01N2330/06—Ceramic, e.g. monoliths

Definitions

  • the invention relates to a device for cleaning exhaust gases from internal combustion engines, in particular diesel soot filters, according to the preamble of patent claim 1.
  • the object of the invention is to prevent these disadvantages by constructive measures.
  • the hollow interior of the ceramic body is also closed at the rear by an insulator, preferably by a ceramic stopper, which preferably has a passage of 1-2 mm in diameter through which the internal electrode is subjected to high voltage is supplied.
  • the supply of the high voltage at the rear has the advantage that very small soot deposits are already present in this area and, moreover, the field strength at the bushing is so high due to the small diameter of the feed line that there is an immediate burning off of the deposits there Soot comes, which in turn prevents the formation of conductive soot bridges.
  • the discharge electrode can be carried by the ceramic body and have the same high-voltage potential as the inner electrode.
  • the tendency towards spark formation in the area of the discharge electrode due to the deposited soot is countered according to the invention in that the counter electrode opposite the discharge electrode has a ceramic coating with high electrical resistance.
  • the teeth of the discharge electrode have a ceramic coating at their tips with a thickness between 0.05 mm and 0.2 mm and an electrical volume resistance per tip of between 1 megohm and 1 gigohm, preferably between lOMegaohm and 100 Megaohm.
  • the ceramic coating of the counterelectrode has a thickness between 0.1 and 0.5 mm and an electrical volume resistance between 1Megaohm.cm 2 and a Gigaohm.cm 2 , preferably between 1 OMegaohm.c ⁇ r and lOOMegaohm.cm 2 .
  • the coating of the discharge electrode and / or counter electrode preferably consists of one of the materials A1203, TiO, ZrO and CrO or mixtures thereof.
  • the inner electrode arranged on the inside of the ceramic body is arranged at a distance from the inlet side and preferably also from the outlet side of the channels of the ceramic body. This prevents the formation of conductive soot bridges in the inlet and outlet areas of the channels of the ceramic body.
  • a PTC thermistor is arranged between the inner electrode which is at high voltage and the inner cylinder surface of the ceramic body.
  • the PTC thermistor preferably increases its volume resistance from values below 10 megohm.cm 2 to at least 100 megohm.cm 2 , preferably 300 megohm.cm 2 , with a temperature increase from 100 ° C. to 500 ° C.
  • the resistance of the ceramic body decreases too much at higher temperatures, the high voltage at the inner electrode must be reduced, since only a limited power can be drawn from the vehicle electrical system from the power supply unit supplying the high voltage.
  • the discharge electrode or counter electrode which is electrically connected in parallel with the inner electrode, would cease to function.
  • the PTC thermistor compensates for the resistance of the ceramic body, which decreases at higher temperatures, so that the function of the discharge electrode or the counterelectrode is not impaired. If an inhomogeneous current distribution occurs in the ceramic body, local heating of the ceramic body also results, which can lead to thermal damage to the ceramic body. The local heating regulates the local power supply back via the increasing resistance of the PTC thermistor, which leads to a uniform distribution of the power supplied.
  • Fig. 1 shows a longitudinal section through a first embodiment of a device according to the invention.
  • 2 shows a longitudinal section through a further embodiment of a device according to the invention.
  • FIG. 3 is a sectional view taken along the line III-III of FIG. 2nd
  • a ceramic body 1 of circular cross-section is fastened through press mats, wire mesh 3 or the like.
  • the hollow cylindrical interior 22 of the ceramic body 1 is closed on both sides by plugs 4, 4 '.
  • a metallic layer 6 serving as an outer electrode and lying on the ground is arranged on the outer cylinder wall of the ceramic body 1.
  • the ceramic body 1 has continuous channels 20 running in the longitudinal direction, which preferably have the brick structure known from EP-A 537219.
  • the two plugs 4, 4 'each have a bushing 23, 23', through which an axially extending, as thin as possible diameter metallic tube 7 is passed, which carries the counterelectrode 28 on the inlet side.
  • inserts (not shown) with shafts or ribs running in the axial direction of the pipe can be provided in the bushings 23, 23 'between the pipe 7 and insulators 4, 4'.
  • the tube 7 tapers on the outlet side to a connection end 12 which engages in a receiving opening 13 of a cylindrical ceramic holder 10 and is supplied with high voltage via a conductor 11 guided in the holder 10.
  • the inner electrode 5 is connected with high voltage via the conductor 11, the connection end 12, the tube 7 and a contact spring 9 attached to the tube 7.
  • An electric field builds up in the ceramic body 1 transversely to the channels 20 running through, between the inner electrode 5, which is at high voltage, and the outer electrode 6, which is at ground.
  • the tube 7 between the insulators 4, 4 ' can be designed as a spray electrode.
  • the ceramic body 1 is preferably produced from a cordierite mass by high pressure extrusion and then fired at high temperatures.
  • the ceramic body 1 should have a very low porosity, preferably less than 0.5%.
  • the height of the channels is usually between 0.6 and 1 mm and the width of the channels 20 is between 3 and 6 mm, depending on the radial position.
  • the discharge electrode is formed by a cylindrical tube body 8 having electron-emitting spray teeth 24, which abuts the tube 2.
  • the counterelectrode 28 opposite the discharge electrode 8 has a cylindrical base body which tapers in a conical manner on the inlet side.
  • the counter electrode 28 has a ceramic coating tion 14.
  • the coating has a thickness of 0.1 to 0.5 mm and has an electrical volume resistance, based on the cm 2 , of 1 megohm.cm 2 to 1 gigohm.cm 2 , preferably from 1OMegaohm.c ⁇ r to 1OOMegaohm.cm 2 .
  • the high voltage at the inner electrode 5 and thus at the counter electrode 28 is approximately plus 8 to 12 KV.
  • the high voltage is preferably proportional to the volume or mass flow of the exhaust gas within an interval of 2 KV / cm to 6KV / cm in relation to the distance between the inner electrode 5 and the outer electrode 6.
  • the exhaust gas loaded with diesel soot particles flowing in at the inlet side A flows into the annular channel 26 formed by the discharge electrode 8 and the counterelectrode 28 against the inlet openings of the channels 20 of the ceramic body 1.
  • the exhaust gas components are ionized in the annular channel 26 and penetrate into the channels 20 of the ceramic body 1. Because of the electrical field built up transversely to the channels 20, the soot particles contained in the exhaust gas and charged by the discharge electrode 8 are deposited on the wall surfaces of the channels 20 and electrochemically by a gas plasma formed from emitted electrons due to the high electrical field strength oxidized. Soot particles of the exhaust gas leaving the annular space 26 cannot reach the interior 22 of the ceramic body 1 and thus the inner electrode 5 due to the stopper 4.
  • soot particles contained in the exhaust gas will penetrate into the channels 20 and, after being deposited on the walls of the channels 20, will be oxidized by the gas plasma.
  • Soot particles, which deposit on the outside of the passage 23 on the stopper 4 or on the tube 5 and form conductive soot bridges there, are burned by sparking due to the small diameter of the tube 7 and the resulting high field strength, so that none are burnt there can form longer conductive soot bridges.
  • the internal electrode 5, which is at high voltage, is also protected from the outlet side B by the plug 4 '. At the outlet side B, the exhaust gas emerging from the channels is already largely free of soot particles.
  • the small diameter of the pipe 7 or the connection end 12 leads to the occurrence of high field strengths, by means of which the soot deposited there burns through sparking.
  • the inner electrode 5 and the outer electrode 6 do not extend over the entire length of the ceramic body 1, so that an almost field-free flow area is retained in the inlet and outlet area of the ceramic body 1. This precludes short-circuiting of the inner electrode 5 with the outer electrode 6 via any soot bridges occurring at the inlet or outlet openings of the channels.
  • FIG. 2 shows a section along the main axis of another embodiment. management form of a diesel soot converter.
  • the ceramic body 1 is electrically and mechanically separated from the discharge electrode 29.
  • the ceramic body 1 which has the continuous channels 20 for the diesel exhaust gases likewise has an annular cross section and is fastened by means of press mats or wire meshes 3 in an enlarged, tubular part of the exhaust pipe 2.
  • the hollow inner part 22 of the ceramic body 1 is closed on the inlet side with a non-conductive, preferably ceramic stopper 4.
  • An electrically conductive layer is arranged on the inner and outer cylinder jacket of the ceramic body 1, which serves as an inner electrode 5 which is connected to high voltage or as an outer electrode 6 which is connected to ground.
  • the hollow interior 22 of the ceramic body 1 is closed on the outlet side by a non-conductive, preferably ceramic stopper 4 ' .
  • the stopper 4 ' has a thin bore through which a metal tube 7, which is as thin as possible in diameter, passes and which makes contact with the inner electrode 5 with the aid of a contact spring 9.
  • the high voltage is fed to the tube 7 through a conductor 11 arranged in a ceramic cylindrical holder 10.
  • the rear end of the tube 7 is tapered to a pin 12 which is electrically connected to the conductor 1 1 and engages in a recess 13 of the holder 10.
  • the high voltage values are essentially identical to those of the embodiment according to FIG. 1, however the high voltage at the inner electrode 5 and at the discharge electrode 29 has a negative polarity.
  • the discharge electrode 29 is arranged electrically and mechanically separate from the ceramic body 1 in the pipe 2 of the exhaust line.
  • the discharge electrode 29 has a basic body 25 which carries cylindrical spray teeth 24 and which has thin, preferably 2 to 4 mm thick pins 18, 18 'on both sides, through which the discharge electrode 8 rests in recesses 19, 19' of ceramic holders 15, 16 is supported.
  • the high voltage is supplied to the discharge electrode 29 through a conductor 17 guided in the holder 16 via the pin 18.
  • the counter electrode 30 surrounding the discharge electrode 29 is formed by a ceramic coating applied to the tube 2 and having a thickness of 0.1 to 0.5.
  • the electrical resistance values correspond to those of the counter electrode 14 in the embodiment according to FIG. 1.
  • a PTC thermistor 27 is arranged between the inner electrode 5 and the inner wall 21 of the ceramic body 1 and increases its resistance when the temperature rises.
  • the PTC thermistor 27 compensates for the increasing resistance of the ceramic body 1 due to the increase in its resistance.
  • the exhaust gas entering A is ionized in the annular space 26 between the discharge electrode 29 and counter electrode 30 and flows through the channels 20 of the ceramic body 1 and leaves the soot filter at B. Because of the electrical field built up between the inner electrode 5 and outer electrode 6, there is a separation of the soot particles contained in the exhaust gas on the side walls of the channels 20. From the walls of the channels 20 pass the temperature causes electrons, which are accelerated towards the soot deposits by the electric field there and initiate an oxidation of the soot deposits upon impact.

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

Abstract

The invention relates to a device for the cleaning of exhaust gases from internal combustion engines, in particular a diesel exhaust soot filter. Said device has a discharge electrode (8), a counterelectrode (28) opposite thereto for electrical charging of the exhaust gas components, a ceramic structure (1) with a circular cross-section and ducts (20) extending therethrough in the direction of flow, and an internal electrode (5) at high voltage. This electrode is arranged on the inner cylinder wall (21) of the ceramic structure (1) and creates an electrical field at right angles to the ducts (20) passing through said ceramic structure. The soot particles are deposited and oxidised on the walls of the ducts (20), and a separation is provided to prevent flow through the hollow internal space (22) of the ceramic structure (1). To prevent the formation of conductive soot bridges between high-voltage-conducting components and earth the separation of the hollow internal space (22) of the ceramic structure (1) is an electrical insulator, preferably a ceramic stopper (4), arranged at the inlet side of the gas stream.

Description

Vorrichtung zum Reinigen von Abgasen aus Verbrennungskraftmaschinen Device for cleaning exhaust gases from internal combustion engines
Die Erfindung betrifft eine Vorrichtung zur Reinigung von Abgasen aus Verbrennungskraftmaschinen, insbesondere Dieselrußfilter, gemäß dem Oberbegriff des Patentanspruches 1.The invention relates to a device for cleaning exhaust gases from internal combustion engines, in particular diesel soot filters, according to the preamble of patent claim 1.
Die Nachteile dieses etwa aus der EP-A 332609 oder EP-A 537219 bekannten Dieselrußfilters sind, daß die im Rußfilter außerhalb der Kanäle des Keramikkörpers abgelagerten Rußpartikel nach einiger Zeit leitende Brücken zwischen Innenelektrode und Masse bilden, die zu parasitären Strömen und per¬ manent sich bildenden Funkenstrecken fuhren.The disadvantages of this diesel soot filter known from EP-A 332609 or EP-A 537219, for example, are that after some time the soot particles deposited in the soot filter outside the channels of the ceramic body form conductive bridges between the inner electrode and the mass, which lead to parasitic currents and are permanent forming spark gaps.
Aufgabe der Erfindung ist es, diese Nachteile durch konstruktive Maßnahmen zu unterbinden.The object of the invention is to prevent these disadvantages by constructive measures.
Dies wird bei einer Vorrichtung der eingangs angeführten Art durch die im Kennzeichen des Patentanspruches 1 angeführten Merkmale erreicht.This is achieved in a device of the type mentioned by the features listed in the characterizing part of claim 1.
Durch das Verschließen des die auf Hochspannung liegende Innen¬ elektrode enthaltenden Hohlraumes kann es zu keiner permanenten Ausbildung von leitenden Rußablagerungen außerhalb der Kanäle des Keramikkörpers kom¬ men.By closing the cavity containing the high-voltage inner electrode, there can be no permanent formation of conductive soot deposits outside the channels of the ceramic body.
Vorzugsweise ist vorgesehen, daß der hohle Innenraum des Kera¬ mikkörpers auch an der Rückseite durch einen Isolator, vorzugsweise durch einen keramischen Stopfen, verschlossen ist, der einen Durchlaß von vorzugs¬ weise l-2mm Durchmesser aufweist, durch den die Innenelektrode mit Hoch¬ spannung versorgt wird.It is preferably provided that the hollow interior of the ceramic body is also closed at the rear by an insulator, preferably by a ceramic stopper, which preferably has a passage of 1-2 mm in diameter through which the internal electrode is subjected to high voltage is supplied.
Die Zuführung der Hochspannung an der Rückseite hat den Vorteil, daß in diesem Bereich bereits sehr geringe Rußablagerungen vorhanden sind und darüber hinaus die Feldstärke an der Durchführung durch den geringen Durch¬ messer der Zuleitung so hoch ist, daß es zu einem sofortigen Abbrennen des dort angelagerten Rußes kommt was wiederum die Ausbildung von leitenden Ru߬ brücken verhindert.The supply of the high voltage at the rear has the advantage that very small soot deposits are already present in this area and, moreover, the field strength at the bushing is so high due to the small diameter of the feed line that there is an immediate burning off of the deposits there Soot comes, which in turn prevents the formation of conductive soot bridges.
Um die Entladungselektrode besonders zu isolieren, kann die Entla¬ dungselektrode vom Keramikkörper getragen werden und auf gleichem Hoch¬ spannungspotential wie die Innenelektrode liegen.In order to particularly insulate the discharge electrode, the discharge electrode can be carried by the ceramic body and have the same high-voltage potential as the inner electrode.
Die Neigung zur Funkenbildung im Bereich der Entladungselek¬ trode durch den abgeschiedenen Ruß wird erfindungsgemäß dadurch begegnet, daß die der Entladungselektrode gegenüberliegende Gegenelektrode eine kera¬ mische Beschichtung mit hohem elektrischen Widerstand aufweist.The tendency towards spark formation in the area of the discharge electrode due to the deposited soot is countered according to the invention in that the counter electrode opposite the discharge electrode has a ceramic coating with high electrical resistance.
Es hat sich als vorteilhaft erwiesen, daß die Zähne der Entladungs¬ elektrode an ihren Spitzen eine keramische Beschichtung mit einer Stärke zwischen 0,05mm und 0,2 mm aufweisen und dabei einen elektrischen Durch¬ gangswiderstand je Spitze zwischen 1 Megaohm und 1 Gigaohm, vorzugsweise zwischen lOMegaohm und 100 Megaohm, besitzen.It has proven to be advantageous that the teeth of the discharge electrode have a ceramic coating at their tips with a thickness between 0.05 mm and 0.2 mm and an electrical volume resistance per tip of between 1 megohm and 1 gigohm, preferably between lOMegaohm and 100 Megaohm.
Es kann erfindungsgemäß auch zweckmäßig sein, daß die kera¬ mische Beschichtung der Gegenelektrode eine Stärke zwischen 0,1 und 0,5 mm aufweist und dabei einen elektrischen Durchgangswiderstand zwischen lMegaohm.cm2 und ein Gigaohm.cm2, vorzugsweise zwischen 1 OMegaohm.cπr und lOOMegaohm.cm2, besitzt.It can also be expedient according to the invention that the ceramic coating of the counterelectrode has a thickness between 0.1 and 0.5 mm and an electrical volume resistance between 1Megaohm.cm 2 and a Gigaohm.cm 2 , preferably between 1 OMegaohm.cπr and lOOMegaohm.cm 2 .
Vorzugsweise besteht die die Beschichtung der Entladungselektrode und/oder Gegenelektrode aus einem der Materialien A1203, TiO, ZrO und CrO oder Mischungen daraus.The coating of the discharge electrode and / or counter electrode preferably consists of one of the materials A1203, TiO, ZrO and CrO or mixtures thereof.
Gemäß einem weiteren erfindungsgemäßen Merkmal ist vorgese¬ hen, daß die an der Innenseite des Keramikkörpers angeordnete Innenelektrode im Abstand von der Einlaßseite und vorzugsweise auch von der Auslaßseite der Kanäle des Keramikkörpers angeordnet ist. Dadurch wird die Ausbildung von leitenden Rußbrücken im Einlaß- bzw. Auslaßbereich der Kanäle des Keramik¬ körpers verhindert.According to a further feature according to the invention, it is provided that the inner electrode arranged on the inside of the ceramic body is arranged at a distance from the inlet side and preferably also from the outlet side of the channels of the ceramic body. This prevents the formation of conductive soot bridges in the inlet and outlet areas of the channels of the ceramic body.
Gemäß einer weiteren Ausfuhrungsform der Erfindung ist vorgese¬ hen, daß zwischen der auf Hochspannung liegenden Innenelektrode und der in¬ neren Zylinderfläche des Keramikkörpers ein Kaltleiter angeordnet ist. Vorzugs¬ weise erhöht der Kaltleiter seinen Durchgangs widerstand von Werten unter 10 Megaohm.cm2 auf mindestens 100 Megaohm.cm2, vorzugswei¬ se 300 Megaohm.cm2, bei einem Temperaturanstieg von 100°C auf 500°C.According to a further embodiment of the invention, it is provided that a PTC thermistor is arranged between the inner electrode which is at high voltage and the inner cylinder surface of the ceramic body. The PTC thermistor preferably increases its volume resistance from values below 10 megohm.cm 2 to at least 100 megohm.cm 2 , preferably 300 megohm.cm 2 , with a temperature increase from 100 ° C. to 500 ° C.
Nimmt bei höheren Temperaturen der Widerstand des Keramikkör¬ pers zu stark ab, so muß die Hochspannung an der Innenelektrode herabgesetzt werden, da von dem die Hochspannung liefernden Netzgerät dem Bordnetz des Fahrzeuges nur eine begrenzte Leistung entnommen werden kann. Dadurch würde bei Fehlen des Kaltleiters die zur Innenelektrode elektrisch parallel ge- schaltene Entladungselektrode bzw. Gegenelektrode ihre Funktion einstellen. Der Kaltleiter dagegen kompensiert durch den Anstieg seines Widerstandes den bei höheren Temperaturen abnehmenden Widerstand des Keramikkörpers, wo¬ durch die Funktion der Entladungselektrode bzw. der Gegenelektrode nicht be¬ einträchtigt wird. Stellt sich im Keramikkörper eine inhomogene Stromvertei¬ lung ein, so ergibt sich weiter eine lokale Erwärmung des Keramikkörpers, welche zu thermischen Beschädigung des Kermamikkörpers führen kann. Die lokale Erwärmung regelt über den wachsenden Widerstand des Kaltleiters die lokale Stromzufuhr zurück, wodurch es zu einer Gleichverteilung der zuge¬ führten Leistung kommt.If the resistance of the ceramic body decreases too much at higher temperatures, the high voltage at the inner electrode must be reduced, since only a limited power can be drawn from the vehicle electrical system from the power supply unit supplying the high voltage. As a result, in the absence of the PTC thermistor, the discharge electrode or counter electrode, which is electrically connected in parallel with the inner electrode, would cease to function. The PTC thermistor, on the other hand, compensates for the resistance of the ceramic body, which decreases at higher temperatures, so that the function of the discharge electrode or the counterelectrode is not impaired. If an inhomogeneous current distribution occurs in the ceramic body, local heating of the ceramic body also results, which can lead to thermal damage to the ceramic body. The local heating regulates the local power supply back via the increasing resistance of the PTC thermistor, which leads to a uniform distribution of the power supplied.
Die Erfindung wird nun näher unter Bezugnahme auf die Zeichnun¬ gen erklärt. In den Zeichnungen zeigen:The invention will now be explained in more detail with reference to the drawings. The drawings show:
Fig. 1 einen Längsschnitt durch eine erste Ausführungsform einer erfindungsgemäßen Vorrichtung. Fig. 2 einen Längsschnitt durch eine weitere Ausfuhrungsform einer erfindungsgemäßen Vorrichtung, undFig. 1 shows a longitudinal section through a first embodiment of a device according to the invention. 2 shows a longitudinal section through a further embodiment of a device according to the invention, and
Fig. 3 eine Schnittansicht längs der Linie III-III der Fig. 2.3 is a sectional view taken along the line III-III of FIG. 2nd
In einem zylinderförmigen Rohr 2 aus Metall ist ein Keramikkör¬ per 1 von kreisringfÖrmigem Querschnitt durch Preßmatten, Drahtgeflechte 3 oder dgl. befestigt. Der hohle zylindrische Innenraum 22 des Keramikkörpers 1 ist zu beiden Seiten durch Stopfen 4, 4' verschlossen. An der Innenwand 21 des Keramikkörpers 1 ist eine elektrisch leitende vorzugsweise metallische Schicht 5 angeordnet, welche als eine mit Hochspannung verbundene Innenelektrode dient. An der äußeren Zylinderwand des Keramikkörpers 1 ist eine als Außenelektrode dienende und an Masse liegende metallische Schicht 6 angeord¬ net. Der Keramikkörper 1 weist in Längsrichtung verlaufende durchgehende Kanäle 20 auf, welche vorzugsweise die aus der EP-A 537219 bekannte Ziegel¬ struktur aufweisen. Die beiden Stopfen 4, 4' besitzen je eine Durchführung 23, 23 ', durch die ein axial verlaufendes, im Durchmesser möglichst dünnes metal¬ lisches Rohr 7 hindurchgeführt ist, welches einlaßseitig die Gegenelektrode 28 trägt. Um das Rohr 7 lagemäßig zu sichern können in den Durchführungen 23, 23' zwischen Rohr 7 und Isolatoren 4, 4' Einsätze (nicht gezeigt) mit in Achs¬ richtung des Rohres verlaufenden Wellen oder Rippen vorgesehen werden. Das Rohr 7 verjüngt sich auslaßseitig zu einem Anschlußende 12, welches in einer Aufnahmeöffhung 13 eines zylinderförmigen keramischen Halters 10 eingreift und über eine in dem Halter 10 geführten Leiter 11 mit Hochspannung versorgt wird. Die Innenelektrode 5 ist über den Leiter 11, das Anschlußende 12, das Rohr 7 und eine am Rohr 7 befestigte Kontaktfeder 9 mit Hochspannung ver¬ bunden. Zwischen der an Hochspannung liegenden Innenelektrode 5 und der an Masse liegenden Außenelektrode 6 baut sich im Keramikkörper 1 quer zu den durchlaufenden Kanälen 20 ein elektrisches Feld auf. Zur Unterstützung dieses Feldes kann das Rohr 7 zwischen den Isolatoren 4,4' als Sprühelektrode ausge¬ bildet sein. Der Keramikkörper 1 wird vorzugsweise aus einer Cordieritmasse durch Hochdruckextrusion hergestellt und anschließend bei hohen Temperaturen gebrannt. Der Keramikkörper 1 soll eine sehr geringe Porosität , vorzugsweise geringer als 0,5%, aufweisen. Die Höhe der Kanäle liegt üblicherweise zwischen 0,6 und lmm und die Breite der Kanäle 20 je nach radialer Lage etwa zwischen 3 und 6mm.In a cylindrical tube 2 made of metal, a ceramic body 1 of circular cross-section is fastened through press mats, wire mesh 3 or the like. The hollow cylindrical interior 22 of the ceramic body 1 is closed on both sides by plugs 4, 4 '. Arranged on the inner wall 21 of the ceramic body 1 is an electrically conductive, preferably metallic layer 5, which serves as an inner electrode connected to high voltage. On the outer cylinder wall of the ceramic body 1, a metallic layer 6 serving as an outer electrode and lying on the ground is arranged. The ceramic body 1 has continuous channels 20 running in the longitudinal direction, which preferably have the brick structure known from EP-A 537219. The two plugs 4, 4 'each have a bushing 23, 23', through which an axially extending, as thin as possible diameter metallic tube 7 is passed, which carries the counterelectrode 28 on the inlet side. In order to secure the pipe 7 in position, inserts (not shown) with shafts or ribs running in the axial direction of the pipe can be provided in the bushings 23, 23 'between the pipe 7 and insulators 4, 4'. The tube 7 tapers on the outlet side to a connection end 12 which engages in a receiving opening 13 of a cylindrical ceramic holder 10 and is supplied with high voltage via a conductor 11 guided in the holder 10. The inner electrode 5 is connected with high voltage via the conductor 11, the connection end 12, the tube 7 and a contact spring 9 attached to the tube 7. An electric field builds up in the ceramic body 1 transversely to the channels 20 running through, between the inner electrode 5, which is at high voltage, and the outer electrode 6, which is at ground. To support this field, the tube 7 between the insulators 4, 4 'can be designed as a spray electrode. The ceramic body 1 is preferably produced from a cordierite mass by high pressure extrusion and then fired at high temperatures. The ceramic body 1 should have a very low porosity, preferably less than 0.5%. The height of the channels is usually between 0.6 and 1 mm and the width of the channels 20 is between 3 and 6 mm, depending on the radial position.
Die Entladungselektrode wird durch einen Elektronen emittierende Sprühzähne 24 aufweisenden zylindrischen Rohrkörper 8 gebildet, der am Rohr 2 anliegt. Die der Entladungselektrode 8 gegenüberliegende Gegenelek¬ trode 28 besitzt einen zylindrischen Grundkörper, der sich einlaßseitig konus- förmig verjüngt. Die Gegenelektrode 28 besitzt eine keramische Beschich- tung 14. Die Beschichtung hat eine Stärke von 0,1 bis 0,5 mm und besitzt einen auf den cm2 bezogenen elektrischen Durchgangswiderstand von 1 Megaohm.cm2 bis lGigaohm.cm2, vorzugsweise von lOMegaohm.cπr bis lOOMegaohm.cm2. Die Hochspannung an der Innenelektrode 5 und damit an der Gegenelektrode 28 beträgt etwa plus 8 bis 12 KV. Vorzugsweise wird die Hochspannung proportio¬ nal dem Volumen oder Massenstrom des Abgases innerhalb eine Intervalles von 2 KV/cm bis 6KV/cm bezogen auf den Abstand zwischen Innenelektrode 5 und Außenelektrode 6 geregelt.The discharge electrode is formed by a cylindrical tube body 8 having electron-emitting spray teeth 24, which abuts the tube 2. The counterelectrode 28 opposite the discharge electrode 8 has a cylindrical base body which tapers in a conical manner on the inlet side. The counter electrode 28 has a ceramic coating tion 14. The coating has a thickness of 0.1 to 0.5 mm and has an electrical volume resistance, based on the cm 2 , of 1 megohm.cm 2 to 1 gigohm.cm 2 , preferably from 1OMegaohm.cπr to 1OOMegaohm.cm 2 . The high voltage at the inner electrode 5 and thus at the counter electrode 28 is approximately plus 8 to 12 KV. The high voltage is preferably proportional to the volume or mass flow of the exhaust gas within an interval of 2 KV / cm to 6KV / cm in relation to the distance between the inner electrode 5 and the outer electrode 6.
Das an der Einlaßseite A einströmende mit Dieselrußpartikeln bela- dene Abgas strömt in den durch die Entladungselektrode 8 und die Gegenelek- trode 28 gebildeten Ringkanal 26 gegen die Einlaßöffnungen der Kanäle 20 des Keramikkörpers 1. Die Abgasbestandteile werden im Ringkanal 26 ionisiert und dringen in die Kanäle 20 des Keramikkörpers 1 ein. Auf Grund des quer zu den Kanälen 20 aufgebauten elektrischen Feldes werden die im Abgas enthaltenen und durch die Entladungselektrode 8 aufgeladenen Rußpartikeln an den Wand¬ flächen der Kanäle 20 abgelagert und elektrochemisch durch ein auf Grund der hohe elektrischen Feldstärke sich bildendes Gasplasma aus emittierten Elektro¬ nen oxidiert. Rußpartikel des den Ringraum 26 verlassenden Abgases können auf Grund des Stopfens 4 den Innenraum 22 des Kermikkörpers 1 und damit die Innenelektrode 5 nicht erreichen. Der überwiegende Teil der im Abgas enthal¬ tenen Rußpartikeln wird in die Kanäle 20 eindringen und nach Ablagerung an den Wänden der Kanäle 20 durch das Gasplasma oxidiert. Rußpartikel, welche sich an der Außenseite des Durchlasses 23 am Stopfen 4 oder am Rohr 5 abla¬ gern und dort leitende Rußbrücken bilden werden auf Grund des geringen Durchmesser der Rohres 7 und der dadurch dort herrschenden hohen Feldstärke durch Funkenbildung verbrannt, so daß sich dort keine längeren leitenden Ru߬ brücken ausbilden können. Auch von der Auslaßseite B her ist die auf Hoch¬ spannung liegende Innenelektrode 5 durch den Stopfen 4 'geschützt. An der Auslaßseite B ist das aus den Kanälen austretende Abgas bereits weitgehend von Rußpartikeln befreit. Werden jedoch Restbestandteile von Ruß an der Auslaßseite B am Rohr 7 bzw. am Abschlußende 12 abgelagert, kommt es auf Grund des geringen Durchmessers des Rohres 7 bzw. des Anschlußendes 12 zum Auftreten von hohen Feldstärken, durch die der dort abgelagerte Ruß durch Funkenbildung verbrennt. Wie aus Fig. 1 ersichtlich ist, erstreckt sich die In¬ nenelektrode 5 und die Außenelektrode 6 nicht über die gesamte Länge des Ke¬ ramikkörpers 1 , so daß im Einlaß- und Auslaßbereich des Keramikkörpers 1 ein annähernd feldfreier Strömungsbereich erhalten bleibt. Dadurch wird ein Kurz¬ schließen der Innenelektrode 5 mit der Außenelektrode 6 über allfallige an den Einlaß- bzw. Auslaßöffnungen der Kanäle auftretende Rußbrücken ausgeschlos¬ sen.The exhaust gas loaded with diesel soot particles flowing in at the inlet side A flows into the annular channel 26 formed by the discharge electrode 8 and the counterelectrode 28 against the inlet openings of the channels 20 of the ceramic body 1. The exhaust gas components are ionized in the annular channel 26 and penetrate into the channels 20 of the ceramic body 1. Because of the electrical field built up transversely to the channels 20, the soot particles contained in the exhaust gas and charged by the discharge electrode 8 are deposited on the wall surfaces of the channels 20 and electrochemically by a gas plasma formed from emitted electrons due to the high electrical field strength oxidized. Soot particles of the exhaust gas leaving the annular space 26 cannot reach the interior 22 of the ceramic body 1 and thus the inner electrode 5 due to the stopper 4. The predominant part of the soot particles contained in the exhaust gas will penetrate into the channels 20 and, after being deposited on the walls of the channels 20, will be oxidized by the gas plasma. Soot particles, which deposit on the outside of the passage 23 on the stopper 4 or on the tube 5 and form conductive soot bridges there, are burned by sparking due to the small diameter of the tube 7 and the resulting high field strength, so that none are burnt there can form longer conductive soot bridges. The internal electrode 5, which is at high voltage, is also protected from the outlet side B by the plug 4 '. At the outlet side B, the exhaust gas emerging from the channels is already largely free of soot particles. However, if residual constituents of soot are deposited on the outlet side B at the pipe 7 or at the end end 12, the small diameter of the pipe 7 or the connection end 12 leads to the occurrence of high field strengths, by means of which the soot deposited there burns through sparking. As can be seen from FIG. 1, the inner electrode 5 and the outer electrode 6 do not extend over the entire length of the ceramic body 1, so that an almost field-free flow area is retained in the inlet and outlet area of the ceramic body 1. This precludes short-circuiting of the inner electrode 5 with the outer electrode 6 via any soot bridges occurring at the inlet or outlet openings of the channels.
Fig. 2 zeigt einen Schnitt längs der Hauptachse einer anderen Aus- führungsform eines Dieselrußkonverters. Beim Dieselrußkonverter nach Fig.2 ist der Keramikkörper 1 elektrisch und mechanisch von der Entladungselek¬ trode 29 getrennt. Der die durchgehenden Kanäle 20 für die Dieselabgase auf¬ weisende Keramikkörper 1 weist gleichfalls kreisringförmigen Querschnitt auf und ist durch Preßmatten oder Drahtgeflechte 3 in einem erweiterten, rohrförmi¬ gen Teil des Abgasrohres 2 befestigt. Der hohle Innenteil 22 des Keramikkör¬ pers 1 ist einlaßseitig mit einem nichtleitenden vorzugsweise keramischen Stop¬ fen 4 verschlossen. Am inneren und äußeren Zylindermantel des Keramikkör¬ pers 1 ist eine elektrisch leitende Schicht angeordnet, welche als eine an Hoch¬ spannung liegende Innenelektrode 5 bzw. als an Masse liegende Außenelek¬ trode 6 dient. Der hohle Innenraum 22 des Keramikkörpers 1 ist an der Ausla߬ seite durch einen nichtleitenden vorzugsweise keramischen Stop¬ fen 4 'verschlossen. Der Stopfen 4' besitzt eine dünnen Bohrung, durch die ein im Durchmesser möglichst dünnes metallisches Rohr 7 hindurchfuhrt, das die Kontaktierung der Innenelektrode 5 mit Hilfe einer Kontaktfeder 9 durchfuhrt. Die Hochspannung wird dem Rohr 7 durch einen in einem keramischen zylin¬ derförmigen Halter 10 angeordneten Leiter 1 1 zugeführt. Das rückseitige Ende des Rohres 7 ist zu einem Stift 12 verjüngt, der mit dem Leiter 1 1 elektrisch verbunden ist und in eine Ausnehmung 13 des Halters 10 eingreift. Die Hoch¬ spannungswerte sind im wesentlichen ident mit jenen der Ausführungsform nach Fig. 1, jedoch weist die Hochspannung an der Innenelektrode 5 und an der Ent¬ ladungselektrode 29 eine negative Polarität auf.2 shows a section along the main axis of another embodiment. management form of a diesel soot converter. In the diesel soot converter according to FIG. 2, the ceramic body 1 is electrically and mechanically separated from the discharge electrode 29. The ceramic body 1 which has the continuous channels 20 for the diesel exhaust gases likewise has an annular cross section and is fastened by means of press mats or wire meshes 3 in an enlarged, tubular part of the exhaust pipe 2. The hollow inner part 22 of the ceramic body 1 is closed on the inlet side with a non-conductive, preferably ceramic stopper 4. An electrically conductive layer is arranged on the inner and outer cylinder jacket of the ceramic body 1, which serves as an inner electrode 5 which is connected to high voltage or as an outer electrode 6 which is connected to ground. The hollow interior 22 of the ceramic body 1 is closed on the outlet side by a non-conductive, preferably ceramic stopper 4 ' . The stopper 4 ' has a thin bore through which a metal tube 7, which is as thin as possible in diameter, passes and which makes contact with the inner electrode 5 with the aid of a contact spring 9. The high voltage is fed to the tube 7 through a conductor 11 arranged in a ceramic cylindrical holder 10. The rear end of the tube 7 is tapered to a pin 12 which is electrically connected to the conductor 1 1 and engages in a recess 13 of the holder 10. The high voltage values are essentially identical to those of the embodiment according to FIG. 1, however the high voltage at the inner electrode 5 and at the discharge electrode 29 has a negative polarity.
Die Entladungselektrode 29 ist elektrisch und mechanisch getrennt vom Keramikkörper 1 im Rohr 2 des Abgasstranges angeordnet. Die Entla¬ dungselektrode 29 besitzt einen zylindrischen Sprühzähne 24 tragende Grund- körper 25, welcher zu beiden Seiten dünne vorzugsweise 2 bis 4 mm dicke Stifte 18, 18' aufweist, durch welche die Entladungselektrode 8 in Ausnehmun¬ gen 19, 19' von keramischen Halterungen 15, 16 abgestützt ist. Die Hochspan¬ nung wird der Entladeelektrode 29 durch einen in der Halterung 16 geführten Leiter 17 über den Stift 18 zugeführt. Die der Entladeelektrode 29 umgebende Gegenelektrode 30 ist durch eine am Rohr 2 angebrachte keramische Beschich¬ tung gebildet, welche eine Stärke von 0, 1 bis 0,5 aufweist. Die elektrischen Wi¬ derstandswerte entsprechen jenen der Gegenelektrode 14 in der Ausführungs¬ form nach Fig. 1.The discharge electrode 29 is arranged electrically and mechanically separate from the ceramic body 1 in the pipe 2 of the exhaust line. The discharge electrode 29 has a basic body 25 which carries cylindrical spray teeth 24 and which has thin, preferably 2 to 4 mm thick pins 18, 18 'on both sides, through which the discharge electrode 8 rests in recesses 19, 19' of ceramic holders 15, 16 is supported. The high voltage is supplied to the discharge electrode 29 through a conductor 17 guided in the holder 16 via the pin 18. The counter electrode 30 surrounding the discharge electrode 29 is formed by a ceramic coating applied to the tube 2 and having a thickness of 0.1 to 0.5. The electrical resistance values correspond to those of the counter electrode 14 in the embodiment according to FIG. 1.
Zwischen der Innenelektrode 5 und der Innenwand 21 des Keramik¬ körpers 1 ist ein Kaltleiter 27 angeordnet, welcher bei Erhöhung der Temperatur seinen Widerstand erhöht. Der Kaltleiter 27 kompensiert durch den Anstieg seines Widerstandes den bei höheren Temperaturen abnehmenden Widerstand des Keramikkörpers 1.A PTC thermistor 27 is arranged between the inner electrode 5 and the inner wall 21 of the ceramic body 1 and increases its resistance when the temperature rises. The PTC thermistor 27 compensates for the increasing resistance of the ceramic body 1 due to the increase in its resistance.
Das bei A eintretende Abgas wird im Ringraum 26 zwischen Entla¬ dungselektrode 29 und Gegenelektrode 30 ionisiert und strömt durch die Ka- näle 20 des Keramikkörpers 1 und verläßt den Rußfilter bei B. Auf Grund des zwischen der Innenelektrode 5 und Außenelektrode 6 aufgebauten elektrischen Feldes kommt es zu einer Abscheidung der im Abgas enthaltenen Rußpartikeln an den Seitenwänden der Kanäle 20. Aus den Wänden der Kanäle 20 treten durch die Temperatur bedingt Elektronen aus, welche durch das dort herrschenden elektrische Feld in Richtung zu den Rußablagerungen beschleunigt werden und bei Auftreffen eine Oxidation der Rußablagerungen einleiten. The exhaust gas entering A is ionized in the annular space 26 between the discharge electrode 29 and counter electrode 30 and flows through the channels 20 of the ceramic body 1 and leaves the soot filter at B. Because of the electrical field built up between the inner electrode 5 and outer electrode 6, there is a separation of the soot particles contained in the exhaust gas on the side walls of the channels 20. From the walls of the channels 20 pass the temperature causes electrons, which are accelerated towards the soot deposits by the electric field there and initiate an oxidation of the soot deposits upon impact.

Claims

Patentansprüche claims
1. Vorrichtung zur Reinigung von Abgasen aus Verbrennungskraftmaschinen, insbesondere Dieselrußfilter, mit einer Entladungselektrode (8;29) und einer dieser gegenüberliegenden Gegenelektrode (28;30) zur elektrischen Aufladung der Abgasbestandteile und einem keramischen Körper (1) von kreisringförmigem Querschnitt und mit in Strömungsrichtung verlaufenden durchgehenden Kanälen (20) und mit einer auf Hochspannung liegenden Innenelektrode (5), welche an der inneren Zylinderwand (21) des Keramik¬ körpers ( 1 ) angeordnet ist und ein elektrisches Feld quer zu den durchge¬ henden Kanälen (20) aufbaut, wobei die Rußpartikeln an den Wänden der Kanäle (20) abgelagert und oxidiert werden und zur Unterbindung einer Durchströmung des hohlen Innenraumes (22) des Keramikkörpers durch das Abgas eine Abtrennung vorgesehen ist, dadurch gekennzeichnet, daß die Abtrennung des hohlen Innenraumes (22) des Keramikkörpers (1) durch einen an der Eintrittseite des Abgasstromes angeordneten elektrischen Isolator, vorzugsweise einen keramischen Stopfen (4), gebildet ist.1. Device for cleaning exhaust gases from internal combustion engines, in particular diesel soot filters, with a discharge electrode (8; 29) and a counter electrode (28; 30) opposite this for the electrical charging of the exhaust gas components and a ceramic body (1) of annular cross section and with in the direction of flow continuous channels (20) and with an internal high-voltage electrode (5), which is arranged on the inner cylinder wall (21) of the ceramic body (1) and builds up an electric field transverse to the continuous channels (20), wherein the soot particles are deposited and oxidized on the walls of the channels (20) and a separation is provided to prevent the exhaust gas from flowing through the hollow interior (22) of the ceramic body, characterized in that the separation of the hollow interior (22) of the ceramic body (1) by an ele arranged on the inlet side of the exhaust gas flow ktric insulator, preferably a ceramic plug (4) is formed.
2. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß der hohle In¬ nenraum (22) des Keramikkörpers (1) auch an der Rückseite durch einen Isolator, vorzugsweise durch einen keramischen Stopfen (4'), verschlossen ist, der einen Durchlaß (23 ') von vorzugsweise 1 -2mm Durchmesser aufweist, durch den die Innenelektrode (5) mit Hochspannung versorgt wird.2. Device according to claim 1, characterized in that the hollow interior (22) of the ceramic body (1) is also closed at the rear by an insulator, preferably by a ceramic plug (4 '), which has a passage (23 ') of preferably 1-2 mm in diameter, through which the inner electrode (5) is supplied with high voltage.
3. Vorrichtung nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß der Iso¬ lator (4) an der Eintrittseite des Abgasstromes ebenfalls einen Durch¬ laß (23) aufweist, durch den ein elektrisch leitendes vorzugsweise rohr- förmiges Verbindungselement (7) hindurchtritt, welches die Gegenelek¬ trode (28) trägt (Fig. 1).3. Apparatus according to claim 1 or 2, characterized in that the isolator (4) on the inlet side of the exhaust gas stream also has a passage (23) through which an electrically conductive, preferably tubular connecting element (7) passes, which carries the counter electrode (28) (FIG. 1).
4. Vorrichtung nach Anspruch 3, dadurch gekennzeichnet, daß der Durch¬ laß (23) des Isolators (4) an der Eintrittseite des Abgasstromes einen Durchmesser von höchstens 10mm aufweist. 4. The device according to claim 3, characterized in that the passage (23) of the insulator (4) on the inlet side of the exhaust gas stream has a diameter of at most 10mm.
5. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß die Entladungselektrode (29) an beiden Enden in dünnen, vorzugsweise 2-5. The device according to claim 1, characterized in that the discharge electrode (29) at both ends in thin, preferably 2-
4mm starken Stiften (18, 18') ausläuft, die in Keramikhalterungen (15, 16) gelagert sind, die die rohrförmige Gegenelektrode (30) beidseitig durch¬ dringen und/oder sich auf ihr abstützen und mindestens eine der beiden Keramikhalterungen (16) eine Hochspannungszuführung ( 17) für die Entladungselektrode (29) enthält.4mm thick pins (18, 18 ' ) which are mounted in ceramic holders (15, 16) which penetrate the tubular counterelectrode (30) on both sides and / or are supported on it and at least one of the two ceramic holders (16) one Contains high voltage supply (17) for the discharge electrode (29).
6. Vorrichtung nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß die Entladungselektrode (8;29) und/oder die ihr gegenüberliegende Ge¬ genelektrode (28;30) eine keramische Beschichtung mit hohem elek¬ trischen Widerstand aufweist.6. Device according to one of claims 1 to 5, characterized in that the discharge electrode (8; 29) and / or the opposing counter electrode (28; 30) has a ceramic coating with high electrical resistance.
7. Vorrichtung nach Anspruch 6, dadurch gekennzeichnet, daß die Sprüh¬ zähne (24) der Entladungselektrode (8;29) an ihren Spitzen eine kera¬ mische Beschichtung mit einer Stärke zwischen 0,05mm und 0,2 mm auf¬ weisen und dabei einen elektrischen Durchgangswiderstand je Spitze zwischen 1 Megaohm und 1 Gigaohm, vorzugsweise zwischen lOMegaohm und 100 Megaohm, besitzen.7. The device according to claim 6, characterized in that the Sprüh¬ teeth (24) of the discharge electrode (8; 29) have at their tips a ceramic coating with a thickness between 0.05mm and 0.2mm and thereby have an electrical volume resistance per tip between 1 megohm and 1 gigohm, preferably between 10 megohms and 100 megohms.
8. Vorrichtung nach Anspruch 6, dadurch gekennzeichnet, daß die keramische Beschichtung der Gegenelektrode (28;30) eine Stärke zwischen 0,1 und 0,5 mm aufweist und dabei einen elektrischen Durchgangswiderstand zwischen 1 Megaohm.cm2 und ein Gigaohm.cm2, vorzugsweise zwischen 1 OMegaohm.cm2 und lOOMegaohm.cm2, besitzt.8. The device according to claim 6, characterized in that the ceramic coating of the counter electrode (28; 30) has a thickness between 0.1 and 0.5 mm and thereby an electrical volume resistance between 1 Megaohm.cm 2 and a Gigaohm.cm 2nd , preferably between 1 OMegaohm.cm 2 and lOOMegaohm.cm 2 .
9. Vorrichtung nach Anspruch 6, dadurch gekennzeichnet, daß die Beschich¬ tung der Entladungselektrode (8;29) und/oder Gegenelektrode (28;30) aus einem der Materialien A1203, TiO, ZrO und CrO oder Mischungen daraus besteht.9. The device according to claim 6, characterized in that the coating of the discharge electrode (8; 29) and / or counter electrode (28; 30) consists of one of the materials A1203, TiO, ZrO and CrO or mixtures thereof.
10. Vorrichtung nach einem der Ansprühe 1- 9, dadurch gekennzeichnet, daß die an der Innenseite des Keramikkörpers (1) angeordnete Innenelek¬ trode (5) im Abstand von der Einlaßseite und vorzugsweise auch von der Auslaßseite der Kanäle (20) des Keramikkörpers (1) angeordnet ist.10. Device according to one of claims 1-9, characterized in that the arranged on the inside of the ceramic body (1) Innenelek¬ trode (5) at a distance from the inlet side and preferably also from the outlet side of the channels (20) of the ceramic body ( 1) is arranged.
1 1. Vorrichtung nach einem der Ansprüche 1-10, dadurch gekennzeichnet, daß zwischen der auf Hochspannung liegenden Innenelektrode (5) und der in¬ neren Zylinderfläche (21 ) des Keramikkörpers ( 1 ) ein Kaltleiter (27) an¬ geordnet ist.1 1. Device according to one of claims 1-10, characterized in that a PTC thermistor (27) is arranged between the high-voltage inner electrode (5) and the inner cylinder surface (21) of the ceramic body (1).
12. Vorrichtung nach Anspruch 1 1, dadurch gekennzeichnet, daß der Kaltlei¬ ter (27) seinen Durchgangswiderstand von Werten unter 10 Megaohm.cm2 auf mindestens 100 Megaohm.cm2, vorzugsweise 300 Megaohm.cm2 bei einem Temperaturanstieg von 100°C auf 500°C erhöht.12. The apparatus of claim 1 1, characterized in that the Kaltlei¬ ter (27) its volume resistance of values below 10 megohm.cm2 increased to at least 100 megohm.cm 2 , preferably 300 megohm.cm 2 with a temperature increase from 100 ° C to 500 ° C.
13. Vorrichtung nach Anspruch 3, dadurch gekennzeichnet, daß das die Ge¬ genelektrode (28) tragende elektrisch leitende rohrförmige Verbindungsele¬ ment (7) im Innenraum (22) des Keramikkörpers (1) zwischen den Isolato¬ ren (4,4') als Sprühelektrode ausgebildet ist.13. The apparatus according to claim 3, characterized in that the counter electrode (28) carrying the electrically conductive tubular connecting element (7) in the interior (22) of the ceramic body (1) between the isolators (4,4 ') is designed as a spray electrode.
14. Vorrichtung nach Anspruch 3 oder 13, dadurch gekennzeichnet, daß in den Durchlässen (23,23 ') der Isolatoren (4,4') zwischen dem rohrförmigen Ver¬ bindungselement (7) und den Isolatoren (4,4') Einsätze mit in Achsrichtung verlaufenden Wellen oder Rippen vorgesehen sind. 14. The apparatus of claim 3 or 13, characterized in that in the passages (23,23 ') of the insulators (4,4') between the tubular Ver¬ connecting element (7) and the insulators (4,4 ') inserts with axially extending shafts or ribs are provided.
PCT/AT1997/000024 1996-02-12 1997-02-10 Device for the cleaning of exhaust gases from internal combustion engines WO1997030274A1 (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
DE59700888T DE59700888D1 (en) 1996-02-12 1997-02-10 DEVICE FOR PURIFYING EXHAUST GASES FROM INTERNAL COMBUSTION ENGINES
AT97904288T ATE188015T1 (en) 1996-02-12 1997-02-10 DEVICE FOR CLEANING EXHAUST GASES FROM COMBUSTION ENGINE
AU17119/97A AU1711997A (en) 1996-02-12 1997-02-10 Device for the cleaning of exhaust gases from internal combustion engines
EP97904288A EP0880642B1 (en) 1996-02-12 1997-02-10 Device for the cleaning of exhaust gases from internal combustion engines
PL97328241A PL328241A1 (en) 1996-02-12 1997-02-10 Apparatus for purifying combustion engine exhaust gas
JP52881497A JP4005137B2 (en) 1996-02-12 1997-02-10 Equipment for cleaning exhaust gas from internal combustion engines
BR9707497-7A BR9707497A (en) 1996-02-12 1997-02-10 Device for purifying flue gases from internal combustion engines.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT0024696A ATA24696A (en) 1996-02-12 1996-02-12 DEVICE FOR PURIFYING EXHAUST GASES FROM INTERNAL COMBUSTION ENGINES
ATA246/96 1996-02-12

Publications (1)

Publication Number Publication Date
WO1997030274A1 true WO1997030274A1 (en) 1997-08-21

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JP (1) JP4005137B2 (en)
AT (2) ATA24696A (en)
AU (1) AU1711997A (en)
BR (1) BR9707497A (en)
CA (1) CA2246353A1 (en)
CZ (1) CZ254898A3 (en)
DE (1) DE59700888D1 (en)
HU (1) HUP9901677A3 (en)
PL (1) PL328241A1 (en)
WO (1) WO1997030274A1 (en)

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FR2781690A1 (en) * 1998-08-03 2000-02-04 Ecia Equip Composants Ind Auto Device for regenerating a particle filter in a vehicle exhaust has electrical heater connected to source of electrical energy in the vehicle
GB2351923A (en) * 1999-07-12 2001-01-17 Perkins Engines Co Ltd Self-cleaning particulate filter utilizing electric discharge currents
GB2358149A (en) * 2000-01-14 2001-07-18 Quantum Fuel Technology Ltd Ionising chamber for reducing exhaust emissions
AT410761B (en) * 2001-03-26 2003-07-25 Meier Stauffer Gerd Dr Soot filter and catalyst for diesel engines includes differential pressure measurement controlling high voltage discharge to burn-off soot
EP1441112A1 (en) * 2003-01-15 2004-07-28 Toyota Jidosha Kabushiki Kaisha An exhaust gas purifying apparatus
AT503022B1 (en) * 2006-06-29 2007-07-15 Fleck Carl M Dr Filter arrangement for separating soot particles from an exhaust flow, comprises electrode arrangement through which exhaust gas flows and which charges soot particles, which are removed from exhaust flow by electrical field or mechanically
FR2907843A1 (en) * 2006-10-26 2008-05-02 Renault Sas Soot particle capturing electrical device for motor vehicle, has inner axial electrodes extending across soot particle agglomeration unit and assembly of radial plates, and passages for exhaust gas arranged in plates around electrodes
EP1974822A2 (en) * 2007-03-27 2008-10-01 Rudolf Bolliger Electrostatic fine dust particulate filter
WO2012028408A1 (en) * 2010-09-02 2012-03-08 Reinhausen Plasma Gmbh Device and method for generating a barrier discharge in a gas flow
DE102010044343A1 (en) * 2010-09-03 2012-03-08 Emitec Gesellschaft Für Emissionstechnologie Mbh Device with an annular electrode for reducing soot particles in the exhaust gas of an internal combustion engine

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DE10102491C2 (en) * 2001-01-19 2003-04-17 Walter Hofmann Method for operating a device in the exhaust system of an internal combustion engine for checking the pollution of the exhaust gas flow with soot particles, and this device
AT500959B1 (en) 2004-11-09 2007-05-15 Carl M Dr Fleck METHOD AND FILTER ARRANGEMENT FOR SEPARATING RUSSIAN PARTICLES
AT501888B1 (en) 2005-06-08 2006-12-15 Fleck Carl M Dr WAVE FILTER WITH PLANAR ELECTRODES
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TWI678233B (en) * 2019-03-29 2019-12-01 劉景文 Combined structure of electrostatic dust cleaning machine

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Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2781690A1 (en) * 1998-08-03 2000-02-04 Ecia Equip Composants Ind Auto Device for regenerating a particle filter in a vehicle exhaust has electrical heater connected to source of electrical energy in the vehicle
US7144448B2 (en) * 1999-07-12 2006-12-05 Perkins Engines Company Limited Autoselective regenerating particulate filter
GB2351923A (en) * 1999-07-12 2001-01-17 Perkins Engines Co Ltd Self-cleaning particulate filter utilizing electric discharge currents
US6660068B1 (en) 1999-07-12 2003-12-09 Perkins Engines Company Limited Autoselective regenerating particulate filter
GB2358149A (en) * 2000-01-14 2001-07-18 Quantum Fuel Technology Ltd Ionising chamber for reducing exhaust emissions
AT410761B (en) * 2001-03-26 2003-07-25 Meier Stauffer Gerd Dr Soot filter and catalyst for diesel engines includes differential pressure measurement controlling high voltage discharge to burn-off soot
CN100365251C (en) * 2003-01-15 2008-01-30 丰田自动车株式会社 Exhause purification device
EP1441112A1 (en) * 2003-01-15 2004-07-28 Toyota Jidosha Kabushiki Kaisha An exhaust gas purifying apparatus
US7514047B2 (en) 2003-01-15 2009-04-07 Toyota Jidosha Kabushiki Kaisha Exhaust gas purifying apparatus
AT503022B1 (en) * 2006-06-29 2007-07-15 Fleck Carl M Dr Filter arrangement for separating soot particles from an exhaust flow, comprises electrode arrangement through which exhaust gas flows and which charges soot particles, which are removed from exhaust flow by electrical field or mechanically
FR2907843A1 (en) * 2006-10-26 2008-05-02 Renault Sas Soot particle capturing electrical device for motor vehicle, has inner axial electrodes extending across soot particle agglomeration unit and assembly of radial plates, and passages for exhaust gas arranged in plates around electrodes
EP1974822A2 (en) * 2007-03-27 2008-10-01 Rudolf Bolliger Electrostatic fine dust particulate filter
EP1974822A3 (en) * 2007-03-27 2010-12-15 BorgWarner BERU Systems GmbH Electrostatic fine dust particulate filter
WO2012028408A1 (en) * 2010-09-02 2012-03-08 Reinhausen Plasma Gmbh Device and method for generating a barrier discharge in a gas flow
US8696996B2 (en) 2010-09-02 2014-04-15 Reinhausen Plasma Gmbh Device and method for generating a barrier discharge in a gas flow
DE102010044343A1 (en) * 2010-09-03 2012-03-08 Emitec Gesellschaft Für Emissionstechnologie Mbh Device with an annular electrode for reducing soot particles in the exhaust gas of an internal combustion engine
US9169752B2 (en) 2010-09-03 2015-10-27 Emitec Gesellschaft Fuer Emissionstechnologies Mbh Device having an annular electrode for decreasing soot particles in the exhaust gas of an internal combustion engine

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CZ254898A3 (en) 1998-11-11
BR9707497A (en) 2000-01-04
EP0880642A1 (en) 1998-12-02
EP0880642B1 (en) 1999-12-22
ATA24696A (en) 2000-10-15
HUP9901677A3 (en) 2000-03-28
JP4005137B2 (en) 2007-11-07
JP2000504805A (en) 2000-04-18
PL328241A1 (en) 1999-01-18
CA2246353A1 (en) 1997-08-21
HUP9901677A2 (en) 1999-08-30
ATE188015T1 (en) 2000-01-15
AU1711997A (en) 1997-09-02
DE59700888D1 (en) 2000-01-27

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