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
  • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
  • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
  • F01N3/38—Arrangements for igniting
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B13/00—Oxygen; Ozone; Oxides or hydroxides in general
  • C01B13/10—Preparation of ozone
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02N—STARTING OF COMBUSTION ENGINES; STARTING AIDS FOR SUCH ENGINES, NOT OTHERWISE PROVIDED FOR
  • F02N11/00—Starting of engines by means of electric motors
  • F02N11/04—Starting of engines by means of electric motors the motors being associated with current generators
  • F02N11/06—Starting of engines by means of electric motors the motors being associated with current generators and with ignition apparatus
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
  • H01T13/00—Sparking plugs
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
  • H05H1/00—Generating plasma; Handling plasma
  • H05H1/24—Generating plasma
  • H05H1/52—Generating plasma using exploding wires or spark gaps
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/10—Internal combustion engine [ICE] based vehicles
  • Y02T10/12—Improving ICE efficiencies

Definitions

• the present invention relates to a method for generating a plasma.
• the present invention also relates to a method for producing ozone.
• the present invention also relates to an ignition method for internal combustion engines, as well as a depollution method for reducing the rate of unburnt in the exhaust gases of combustion appliances.
• the present invention further relates to a device for implementing these methods.
• the object of the invention is that the flow of current affects a significantly increased volume of the surrounding gas.
• the inventive idea which is the basis of the invention consists in using for at least one of the electrodes a porous ceramic coating of which at least some of the pores contain an electrically conductive body.
• spark is meant to denote the gaseous space concerned by the passage of the current, without this term by itself referring to a determined form of this space nor a determined duration of the passage of the contact
• the spark is itself continuous. The effect obtained is visible to the naked eye, the spark taking a diameter of the order of 1 mm to a few mm in the vicinity of the active surface defined by the coating.
• the method for generating a plas_ma_e__Lt_ characterized in that two electrodes are placed opposite one another, at least one of which has an active surface defined by a ceramic coating of which pores contain an electrically conductive body, and in that one establishes between these electrodes a potential difference capable of causing an electric current between them.
• the method for producing ozone is characterized in that two electrodes, one of which is placed opposite one another, in a gas containing oxygen at least has an active surface defined by a ceramic coating, the pores of which contain an electrically conductive body, and in that there is established between these electrodes a potential difference capable of causing an electric current between them.
• the ignition method for a combustion engine is characterized in that two electrodes are placed facing each other in a combustion chamber of the engine, at least one of which has an active surface defined by a ceramic coating of which pores contain an electrically conductive body, and in that one establishes between these electrodes a potential difference capable of causing an electric current between them.
• the depollution method for reducing the rate of unburnt in the exhaust gases of combustion appliances, in particular in the exhaust gases produced by a heat engine is characterized in that 'two electrodes are placed opposite one another in an exhaust gas flow path, at least one of which has an active surface defined by a ceramic coating, the pores of which contain an electrically conductive body, and in that one establishes between these electrodes a potential difference capable of causing an electric current between them.
• ozone thanks to residual free oxygen or, for example, by injecting air into the exhaust, results in post-combustion of the exhaust gases, thus reducing the unburnt rate, i.e. hydrocarbons and carbon monoxide in exhaust gases.
• the device for implementing one of the above methods is characterized in that it comprises two electrodes, one of which at least has an active surface defined by a ceramic coating whose pores contain an electrically conductive body, and means for connecting these electrodes to the terminals of a voltage source producing a potential difference sufficient to cause an electric current therebetween.
• FIG. 1 is a schematic perspective view of an experiment in producing sparks against an insulating surface
• FIG. 2 is a view similar to Figure 1 but relating to the production of a spark in the context of a method according to the invention
• FIG. 3 is a view similar to Figure 2 but relating to another method of producing sparks in the context of a method according to the invention
• - Figure 4 is a diagram of an ignition device for internal combustion engines
• - Figure 5 is a graph showing the intensity of the spark current as a function of time in the context of a method according to the invention
• FIG. 6a, 6b, and 6c show schematically three modes of producing sparks according to the invention
• FIG. 7 and 8 are partial views of two embodiments of spark plugs implementing the ignition method according to the invention.
• FIG. 9 is a schematic view of an internal combustion engine implementing the depollution method according to the invention.
• the free end of a metal electrode 1 in the form of a rod is placed opposite a substantially flat surface of an electrically insulating coating 2 carried by a conductive support. 3.
• a potential difference is established between the electrode 1 and the conductive support 3.
• a filiform spark 4 is established between the electrode 1 and the surface of the insulating coating 2.
• the spark 4 also forms filiform ramifications 5. This results in a certain increase in the volume concerned by the spark.
• this process cannot be used industrially because after, for example, a hundred sparks thus produced, the insulator 2 ends up being pierced at the place where it receives the filiform spark 4, after which the ramifications 5 cease to form.
• electrode 1 in the form of a rod whose free end 1a, defined by the metal of electrode 1, and which is of pointed shape in this example is directed perpendicularly to an electrode comprising an electrically conductive support 3 and a coating which defines the planar active surface of the electrode.
• the coating designated by the reference 2 ', is a porous ceramic coating, the pores of which contain an electrically conductive body and an electrically insulating body.
• the ceramic coating is preferably of the alumino-siliceous type whose exact composition, in particular the proportion of silica, the proportion of alumina and the proportion of any other components is defined in a known manner so that the coefficient of thermal expansion of the coating substantially corresponds to that of the metal support 3 of the electrode.
• This coating can be applied in one or more layers on the support 3 in the form of slip, that is to say in the form of a diluted paste containing the mixture of components required.
• the coating is baked.
• the baked coating has pores and the abovementioned electrically conductive body is crystallized from these pores, for example a zinc oxide.
• the zinc oxide it is dissolved, it is applied in the form of a solution and then the solvent is removed to allow the zinc oxide to crystallize in the pores.
• an electrically insulating body that is to say a better insulator than the coating itself, is also included in the pores of the coating.
• a chromium oxide for example obtained by decomposition of chromic acid. To apply this oxide, it is dissolved, it is applied to the coating in the form of a solution, and the solvent is removed to allow the chromium oxide to crystallize in the pores of the coating.
• zinc oxide can be applied to a coating layer, chromium oxide to a next coating layer, etc.
• a coating which is perfectly suitable for the implementation of the present invention is described in US-A-4 615 913.
• the thickness of the coating is for example of the order of mm in the case of the method of laying the coating explained more high.
• the latter takes substantially the shape shown in FIG. 2, and in particular comprises a threadlike region 7 leaving from the end perpendicularly towards the coating 2 ', then a volume region flaring in a corolla 8 towards the coating 2' and having the axis of symmetry substantially the axis of the region 7.
• the region in corolla 8 has a height H and a diameter D which are both of the order of 2 to 8 mm when the applied potential difference is approximately 50 V.
• the dimensions of the region 8 are substantially independent of the spacing L between l 'electrode 1 and coating 2'. If this spacing varies, it is the length of the region 7 which varies correspondingly.
• Region 8 of the spark is formed by a plasma, and ozone is observed when the gas surrounding the electrodes contains free oxygen.
• the electrode 1 is replaced by a metal plate 9 whose active face is planar and parallel to that defined by the coating 2 '.
• a sufficient potential difference is applied between the metal plate 9 whose active face is flat and the support 3, a large number of sparks resembling those of FIG. 2 appear between the plate 9 and the coating 2 ′, that is to say having a filiform region 71, 74, 75 and a corolla region 81, 84, 85 in contact with the coating 2 '.
• the filiform regions such as 71, 74, 75 extend from any points A1, A2, A3, A4, A5 .... An and the vertices of the corolla regions such as 81, 84, 85.
• This process allows, like the previous one, to produce plasma in regions such as 81, 84, 85 and also to produce ozone if the surrounding gas contains free oxygen.
• the spark current has the form very rapidly damped oscillation (more quickly damped than in conventional ignition devices).
• the ignition circuit comprises, in series between the terminals of an accumulator battery 11, the primary 13a of an ignition “coil” 13 (we know that what 'it is agreed to call “ignition coil” is in fact a transformer with very high transformation ratio), the emitter-collector path of a transistor 15, and a breaking device 17.
• the base of the transistor 15 is connected by a resistor 12 to the positive terminal of the battery 11, as well as the end of the primary 13a which is opposite to the transistor 15.
• An energy absorption device 16 such as a silicon carbide (see FR -A-2 401 500 and FR-A-2 423 049), is mounted between the collector and the emitter of the transistor 15 to protect the latter during the opening of the breaking device 17.
• the secondary 13b of the coil d ignition 13 has a terminal connected to the metal ground 14 of an internal combustion engine 18 and a terminal connected to the electrode c insulated inlet 1 of a spark plug 19 (FIG. 7) of which an electrically conductive base 19a is screwed into the metallic mass 14.
• the electrode 1 is retained in a central position inside the base 19a by an insulating ring 19b.
• the spark plug 19 Facing the central electrode 1, the spark plug 19 includes the coating 21 of the same kind as that described with reference to FIG. 2, deposited on a metal support 20 suspended from the base 19a by electrically conductive tabs 24a.
• Support 20 has the form of a cup whose concavity is turned towards the electrode 1 and, similarly, the active surface of the coating 21 has a form of concave cup turned towards the free end of the electrode 1.
• the active end of the electrode 1 and the active surface of the coating 21 are in the combustion chamber 26.
• the end lb of the él_ec_t_rj-ie_ 1 opposite the combustion chamber 26 is used for connection to one of the terminals of the secondary 13b (if necessary by means of an ignition distributor) .
• the thread 19e of the base 19a constitutes the means of connection of the electrode 20-21 with the other terminal of the winding 13b.
• the breaking device 17 of FIG. 4 opens, the current through the primary 13a is suddenly interrupted. This interruption causes the transistor 15 to go even more suddenly from the saturated state to the blocked state.
• the energy absorber 16 absorbs dangerous energy in the event that an excessive potential difference tends to be established between the emitter and the collector of the transistor 15 during the rupture.
• this rupture causes a high induced voltage in the secondary 13b, of several tens of kilovolts, which causes, between the electrodes 1 and 20-21 of FIG. 7, a spark 22 similar to that shown in FIG. 2.
• the circuit parameters are chosen so that the aforementioned induced voltage is as low as possible to produce the spark without producing nitrogen oxides.
• 20-21 is constituted by the mixture of fuel and oxidizer which has been admitted into the combustion chamber 26 of the engine 18. In fact, this mixture has access to the electrodes by the openings 19d left free between the legs 24.
• the invention causes the ignition of the fuel-oxidant mixture very efficiently and quickly thanks to the generation of plasma and the production of ozone.
• the engine 18 is of the semi-diesel type which, in known manner, has the following operating characteristics: injection of a fuel such as diesel by means of an injector 23 during the time of admission under, one, .pressLon. of. around 30 to 40 bars (3 to 4 MPa) chosen to ensure
• the coating 21 of the electrode 20 has an active surface in the form of a concave hemisphere, which promotes the corolla development of the spark 22.
• the electrode 40 has a shape similar to the electrode 1, and is coaxial with the electrode 1.
• the coating 41 is formed on the substantially conical end, directed towards the electrode 1, of the electrode 40. Between these two electrodes is formed, under an appropriate potential difference, a volume spark 42 which substantially covers the coating 41. If the two electrodes 1, 40 are separated from one another, the volume spark 42 is connected to the electrode 1 by a filiform spark such as 7 in FIG. 2.
• the spark plug 30 has a base 31 screwed into the metallic mass 14 of an engine such as the engine 18 of FIG. 4, so as to be in electrical contact with said metallic mass.
• the base 31 is crossed axially by a conductive pin 32, isolated from the base 31 by an insulating sheath 33.
• the conductive pin 32 is connected to the center of an electrode 34 which bears on its annular surface facing towards the base 31 a coating 36 of the same kind as that described with reference to FIG. 2.
• a similar coating 37 is carried by the face of the base 31 facing the electrode 34.
• the coatings 36 and 37 are separated from one another. another of a distance, for example 1 mm, suitable for the formation of sparks when the secondary 13b establishes a potential difference between the base 31 and the electrode 34.
• the outlet of the exhaust manifold 62 of this engine is connected to a chamber 63 into which opens as a whistle, at 64, an air inlet 66 subjected to a dynamic pressure sensed at the front of the vehicle.
• a suitable soundproofing means can be pl_a_o dans- the air inlet 66. Thanks to the whistle entry, the air enters the chamber 63 despite the pressure that may prevail in it, at least periodically.
• a candle 67 which can be of the type described with reference to FIG. 7 or of the type described with reference to FIG. 8. Suitably supplied with electricity, this candle produces sparks which produce at their turn of the plasma and, thanks to the oxygen arriving in 64, of the ozone.
• the unburnt residues of combustion in the engine 61 are burned downstream of the spark plug 67, which reduces the rate of carbon monoxide and hydrocarbons in the exhaust gases emitted by the vehicle thus equipped. It is also possible to supply the candle with direct current, to produce a continuous spark.
• a spark plug constituting a device according to the invention could comprise a central electrode in the form of a rod presenting the coating, and a tubular electrode.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Chemistry (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Plasma & Fusion (AREA)
• Health & Medical Sciences (AREA)
• Toxicology (AREA)
• Inorganic Chemistry (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Spark Plugs (AREA)
• Exhaust Gas After Treatment (AREA)

Priority Applications (1)

Applications Claiming Priority (3)

Publications (1)

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ID=36764051

Family Applications (1)

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Citations (3)

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• 1989
  • 1989-06-23 FR FR8908404A patent/FR2649577B1/fr not_active Expired - Fee Related
• 1990
  • 1990-06-21 ZA ZA904839A patent/ZA904839B/xx unknown
  • 1990-06-22 EP EP90910128A patent/EP0478672A1/de not_active Withdrawn
  • 1990-06-22 WO PCT/FR1990/000458 patent/WO1991000680A1/fr not_active Application Discontinuation
  • 1990-11-15 CN CN90109168A patent/CN1061505A/zh active Pending

Patent Citations (3)

Non-Patent Citations (1)

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