GB2423945A - Exhaust gas conditioning device - Google Patents

Exhaust gas conditioning device Download PDF

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Publication number
GB2423945A
GB2423945A GB0504896A GB0504896A GB2423945A GB 2423945 A GB2423945 A GB 2423945A GB 0504896 A GB0504896 A GB 0504896A GB 0504896 A GB0504896 A GB 0504896A GB 2423945 A GB2423945 A GB 2423945A
Authority
GB
United Kingdom
Prior art keywords
exhaust gas
conditioning device
gas conditioning
discharge
electrical
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB0504896A
Other versions
GB0504896D0 (en
GB2423945B (en
Inventor
Marc Isherwood
Ernest Gwyn Jones
Michael Leonard Lucas
Robert Moore
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Priority to GB0504896A priority Critical patent/GB2423945B/en
Publication of GB0504896D0 publication Critical patent/GB0504896D0/en
Publication of GB2423945A publication Critical patent/GB2423945A/en
Application granted granted Critical
Publication of GB2423945B publication Critical patent/GB2423945B/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/32—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by electrical effects other than those provided for in group B01D61/00
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • 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
    • B03C3/38—Particle charging or ionising stations, e.g. using electric discharge, radioactive radiation or flames
    • B03C3/383—Particle charging or ionising stations, e.g. using electric discharge, radioactive radiation or flames using radiation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/0892—Electric or magnetic treatment, e.g. dissociation of noxious components
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2259/00—Type of treatment
    • B01D2259/80—Employing electric, magnetic, electromagnetic or wave energy, or particle radiation
    • B01D2259/818—Employing electrical discharges or the generation of a plasma
    • 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
    • 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
    • B03C3/017—Combinations of electrostatic separation with other processes, not otherwise provided for
    • 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
    • F01N2240/00—Combination 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
    • F01N2240/04—Combination 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 an electric, e.g. electrostatic, device other than a heater
    • 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
    • F01N2240/00—Combination 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
    • F01N2240/16—Combination 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 an electric heater, i.e. a resistance heater

Abstract

The device includes a housing 1 forming a recombustion chamber between an inlet (10, fig 2) for exhaust gases and an outlet (13, fig 2) for exhaust gases. An expansion chamber (11, fig 2) causes the exhaust gases to slow down during passage through the recombustion chamber. An electrical discharge assembly 15 is mounted within the housing and includes an array of needles 16 forming multiple discharge points protruding from a matrix 18 of high temperature insulation material. The needles 16 are disposed opposite an electrostatic discharge plate 8. The assembly 15 is supplied with a high voltage which is controlled to produce an electrical discharge for particle capture alternating with a recombustion phase in which the supplied voltage is sufficient to cause a plasma discharge. The discharge assembly 15 includes an electrical heater 24 to increase the temperature of the assembly during plasma discharge.

Description

EXHAUST GAS CONDITIONING DEVICE
TECHNICAL FIELD OF THE INVENTION
This invention relates to a device for conditioning the exhaust gases of an internal combustion engine and reducing the amount of particulate matter therein prior to emission into the atmosphere.
BACKGROUND
Devices for reducing the level of noxious gases and potentially harmful particles present in the exhaust of an internal combustion engine are already known. Such devices must be both durable and reliable in operation. However, devices which are exposed to the hot gases of an exhaust system are highly vulnerable to chemical attack, heat, corrosion, erosion, humidity and build up of exhaust residues. Electrical devices are particularly at risk in such an environment since the insulation properties of electrical insulators are seriously and quickly degraded by such agents.
Whilst known gas conditioning devices may work reasonably well when the engine runs heavily on load they are not generally very effective at low exhaust temperatures and with low NOX gas levels.
The present invention seeks to provide a new and inventive form of exhaust gas conditioning device which is both efficient and robust.
SUMMARY OF THE INVENTION
The present invention provides an exhaust gas conditioning device which includes a housing forming a recombustion chamber, an inlet for exhaust gases, an outlet for exhaust gases, an electrical discharge assembly mounted within the housing and including multiple discharge points, means for supplying a high voltage to the discharge assembly sufficient to cause a plasma discharge, and heating means arranged to increase the temperature of the discharge assembly during said plasma discharge.
The device preferably includes a temperature sensor arranged to control the operation of the heating means.
Preferably the device includes an electrical control system which is arranged to generates an electrostatic field within the recombustion chamber to cause electrostatic deposition of particulate matter present in the exhaust gases. The control system preferably employs a feedback arrangement which acts to maintain the electrostatic field below the electrical flashover point. - The electrical discharge assembly may be used to generate the electrostatic field in addition to producing the plasma discharge. The control system preferably operates the device with alternating capture and recombustion phases.
A preferred form of discharge assembly has an array of needles encapsulated within a matrix of electrical insulation material with the tips of the needles protruding. The heating means may also be enclosed within the insulating matrix. Preferably the tips of the needles are disposed substantially equidistant from an electrical discharge plate.
The discharge assembly is preferably mounted substantially centrally of a wall portion of the housing which is formed of electrical insulation material.
There is preferably an expansion chamber between the exhaust inlet and the recombustion chamber whereby the exhsust gases are caused to slow down on passage through the recombustion chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
The following description and the accompanying drawings referred to therein are included by way of non-limiting example in order to illustrate how the invention may be put into practice. In the drawings: Figure 1 is a vertical axial section through an exhaust gas conditioning device in accordance with the invention; Figure 2 is the horizontal section lI-Il through the exhaust gas conditioning device, viewed from above; and Figure 3 is a schematic block diagram of the electrical system of the exhaust gas conditioning device.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring firstly to Fig.s I and 2, the exhaust gas conditioning device includes a housing I of generally rectangular plan, which forms a recombustion chamber. The housing has a top wall 2 which is provided with four depending side walls 3-6, all formed of a high temperature material with good electrical insulation properties such as a ceramic, mica etc.. The bottom part 7 of the housing is formed of an electrically conductive metal (e.g. steel) which provides a centrally disposed, generally rectangular electrical discharge plate 8. The ceramic top part may be secured to the bottom 7 by a flange 9, or other suitable means.
At one end of the housing an input pipe 10 for exhaust gases enters the combustion chamber through the bottom wall 7 via an expansion chamber 11. At the opposite end of the housing a compression chamber 12 is similarly connected via the bottom wall 7, leading to an outlet pipe 13.
The top wall 2 carries an electrostatic discharge assembly 15 of substantially the same plan as the discharge plate 8. The assembly includes a multiplicity of electrically conducting needles 16 secured to an electrode plate 17. The needles are encapsulated within a block 18 formed from a matrix of high temperature electrical insulation material such as ceramic, with the tips of the needles protruding from the block substantially equidistant from the discharge plate 8. The assembly 15 is secured by an electrically conductive metal pin 19, connected to th& plate 17, which passes through the insulating top wall 2 with opposing electrical insulators 20 and 21. A high voltage supply cable 22 is connected to the pin 19 externally of the housing. The ceramic block 18 also contains one or more electrical heating elements 24, powered via heat resistant cables which pass through the insulators 20 and 21.
A temperature sensor 26 is thermally coupled to the underside of the discharge plate 8 to provide a temperature signal via cables 27.
Referring to Fig. 3, the electrical system for the exhaust conditioning device includes a control unit 30 which receives power from a vehicle battery 31 and supplies a control voltage to a high voltage generation unit 32 which in turn supplies a high voltage to the discharge assembly via cable 22. The high voltage unit is mounted close to the housing I to minimise the length of the high voltage cable, whereas the control unit 30 and any associated controls or function indicators may be mounted in any convenient position within the vehicle. The control unit 30 also controls the heating element 24 via cables 25, and receives thermostatic control input from the temperature sensor 26 via cables 27. The high voltage supply and the heater supply share a common electrical return path via the metallic exhaust system. The control unit 30 may include a central processor, program memory, integrated circuits, both analogue and digital, together with suitable input and output interfaces.
In use, the housing I is connected in the exhaust system of the motor vehicle via pipes 10 and 13. The expansion chamber 11 causes the incoming exhaust gases to slow down before entering the housing I so that the gases pass relatively slowly between the exposed tips of the needles 16 and the discharge plate 8. After passing through the housing the treated gases pass through the compression chamber 12 to be expelled through the exhaust system in the usual way.
The control unit 30 uses the input from the temperature sensor 26 to operate the heating element 24 and maintain an efficient working temperature at the discharge assembly. The heating element may be turned on continuously or periodically to increase the temperature of particulate material which is captured by the discharge assembly and induce a reburn of captured particles whenever the engine gases are not hot enough to achieve this. There is a minimum amount of heat loss from the discharge assembly since only the electrode tips are exposed to the cooling effect of the exhaust stream The hot discharge assembly 15 works in combination with a high voltage electrostatic ionising field between the needles 16 and the discharge plate 8. The control unit 30 adjusts the output voltage of the high voltage generator to create a negative (or positive) charge at the discharge assembly. During a capture phase the resulting electrostatic field is regulated at a level at which the assembly 15 captures particulate matter from the exhaust gases without creating a flashover. In the event of changes in the electrical insulation values, which may vary dramatically in this environment, the control unit responds by reducing the voltage output to just below the flashover threshold. The control unit periodically explores the flashover threshold by momentarily increasing the output voltage until flashover occurs, thereby maintaining an optimum electrostatic capture field. The high voltage generator may, for example, use a pulse transformer which includes a primary input winding and a high voltage output winding. When flashover occurs this may be sensed by detecting pulses induced in a transformer winding to provide feedback information for the control unit.
The control unit also periodically operates the voltage generator at a sufficiently high level to produce ozone and produce a plasma flame, which induces a reburn of the particles retained during the capture phase.
The mixing of ozone with the exhaust gases induces a higher combustion temperature and also provides a form of readily available oxygen to act as a catalyst to the required chemical changes. For example, poisonous carbon monoxide may be changed more readily to carbon dioxide in the presence of ozone. The electrical heater may be turned off during the electrostatic capture phase but turned on during the combustion phase to aid ignition of particulate matter.
The high temperature, electrically insulated recombustion chamber formed by the housing I can more readily withstand the harsh environment without electrical insulation breakdown. This is achieved by fixing the high voltage components directly into the insulated part of the housing with large electrical clearances from adjacent metalwork.
Although residual deposits will still form on the inside of the housing, the arrangement reduces electrical tracking and minimising electrical insulation stresses by virtue of the reduced voltage gradient to the nearest earth point.
The device thus captures carbon or other particles present in the exhaust gases and holds them in a position where they can be reburnt. During the combustion phase, environmentally undesirable gases are substantially reduced using the small residues of unburnt fuel which are usually present. This process may be carried our continuously or intermittently while the engine is running. Moreover, the removal of captured particles is effective at all engine temperatures by generating additional heat and ozone. The device also continues to function effectively over a long period even in the harsh environment of an exhaust system. - A preconditioning high voltage electrode could be fitted prior to the particle capture electrode. Furthermore, although a single discharge electrode is used to effect electrostatic particle capture and combustion it will be appreciated that the housing could include separate electrodes to carry out both functions simultaneously.
It will be appreciated that the features disclosed herein may be present in any feasible combination. Whilst the above description lays emphasis on those areas which, in combination, are believed to be new, protection is claimed for any inventive combination of the features disclosed herein.
* * * * * * * *

Claims (13)

CLMMS
1. An exhaust gas Conditioning device which includes a housing forming a recombustion chamber, an inlet for exhaust gases, an outlet for exhaust gases, an electrical discharge assembly mounted within the housing and including multiple discharge points, means for supplying a high voltage to the discharge assembly sufficient to cause a plasma discharge, and heating means arranged to increase the temperature of the discharge assembly during said plasma discharge.
2. An exhaust gas conditioning device according to Claim I which includes a temperature sensor arranged to control the operation of the heating means.
3. An exhaust gas conditioning device according to Claim 1 or 2 which includes an electrical control system arranged to generate an electrostatic field within the recombustion chamber to cause electrostatic deposition of particulate matter present in the exhaust gases.
4. An exhaust gas conditioning device according to Claim 3 in which the electrical control system employs a feedback arrangement which acts to maintain the electrostatic field below an electrical flashover point
5. An exhaust gas conditioning device according to Claim 3 or 4 in which the electrical control system is arranged to produce alternating capture and recombust ion phases. - 10-
6. An exhaust gas Conditioning device according to Claim 3, 4 or 5 in which the electrical discharge assembly is used to generate the electrostatic field in addition to producing the plasma discharge.
7. An exhaust gas conditioning device according to any Preceding claim in which the discharge assembly has an array of needles encapsulated within a matrix of electrical insulation material with the tips of the needles Protruding.
8. An exhaust gas conditioning device according to Claim 7 in which the heating means is enclosed within the insulation matrix.
9. An exhaust gas conditioning device according to Claim 7 or 8 in which the discharge assembly is mounted substantially centrally of a wall portion of the housing which is formed of electrical insulation material.
10. An exhaust gas conditioning device according to any Preceding claim in which said multiple discharge points are disposed substantially equidistant from an electrical discharge plate.
11. An exhaust gas conditioning device according to any Preceding claim which has an expansion chamber between the exhaust inlet and the recombustion chamber whereby the exhaust gases are caused to slow down on passage through the recombust ion chamber.
12. An exhaust gas conditioning device according to Claim 11 which has a compression chamber between the recombustion chamber and the exhaust outlet.
13. An exhaust gas conditioning device substantially as -11 - described with reference to the drawings.
* * * * * * * *
GB0504896A 2005-03-10 2005-03-10 Exhaust gas conditioning device Expired - Fee Related GB2423945B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB0504896A GB2423945B (en) 2005-03-10 2005-03-10 Exhaust gas conditioning device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB0504896A GB2423945B (en) 2005-03-10 2005-03-10 Exhaust gas conditioning device

Publications (3)

Publication Number Publication Date
GB0504896D0 GB0504896D0 (en) 2005-04-13
GB2423945A true GB2423945A (en) 2006-09-13
GB2423945B GB2423945B (en) 2008-07-23

Family

ID=34452095

Family Applications (1)

Application Number Title Priority Date Filing Date
GB0504896A Expired - Fee Related GB2423945B (en) 2005-03-10 2005-03-10 Exhaust gas conditioning device

Country Status (1)

Country Link
GB (1) GB2423945B (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB850321A (en) * 1956-01-02 1960-10-05 Otto Styrie Method of and apparatus for purifying and decontaminating exhaust gases of combustion devices
US4077888A (en) * 1975-12-08 1978-03-07 John Stewart Rhoades Arc discharge apparatus

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB850321A (en) * 1956-01-02 1960-10-05 Otto Styrie Method of and apparatus for purifying and decontaminating exhaust gases of combustion devices
US4077888A (en) * 1975-12-08 1978-03-07 John Stewart Rhoades Arc discharge apparatus

Also Published As

Publication number Publication date
GB0504896D0 (en) 2005-04-13
GB2423945B (en) 2008-07-23

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PCNP Patent ceased through non-payment of renewal fee

Effective date: 20160310