EP0194131B1 - Procédé et appareil pour filtrer les particules solides à l'échappement d'un moteur Diesel - Google Patents

Procédé et appareil pour filtrer les particules solides à l'échappement d'un moteur Diesel Download PDF

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Publication number
EP0194131B1
EP0194131B1 EP86301517A EP86301517A EP0194131B1 EP 0194131 B1 EP0194131 B1 EP 0194131B1 EP 86301517 A EP86301517 A EP 86301517A EP 86301517 A EP86301517 A EP 86301517A EP 0194131 B1 EP0194131 B1 EP 0194131B1
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EP
European Patent Office
Prior art keywords
exhaust
engine
intake
line
filter
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EP86301517A
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German (de)
English (en)
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EP0194131A1 (fr
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Charles D. Wood Iii
Martin B. Treuhaft
Raymond F. Baddour
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BREHK VENTURES
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BREHK VENTURES
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Priority to AT86301517T priority Critical patent/ATE79158T1/de
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    • 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
    • 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
    • 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
    • F01N3/022—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 characterised by specially adapted filtering structure, e.g. honeycomb, mesh or fibrous
    • F01N3/0222—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 characterised by specially adapted filtering structure, e.g. honeycomb, mesh or fibrous the structure being monolithic, e.g. honeycombs
    • 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
    • F01N3/0233—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 periodically cleaning filter by blowing a gas through the filter in a direction opposite to exhaust flow, e.g. exposing filter to engine air intake
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/52—Systems for actuating EGR valves
    • F02M26/59—Systems for actuating EGR valves using positive pressure actuators; Check valves therefor
    • F02M26/60—Systems for actuating EGR valves using positive pressure actuators; Check valves therefor in response to air intake pressure
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B3/00—Engines characterised by air compression and subsequent fuel addition
    • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
    • F02M26/14—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories in relation to the exhaust system
    • F02M26/15—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories in relation to the exhaust system in relation to engine exhaust purifying apparatus

Definitions

  • the field of the instant invention is reduction of the emission level in diesel engine exhaust, and in a more specific vein methods and apparatus for removal of solid particulate matter found in diesel engine exhaust.
  • diesel engine has been relied upon increasingly to power automotive vehicles due to its fuel economy in comparison to conventional gasoline engines.
  • Commercially available diesel engines for highway usage are conveniently classified into two categories, namely, those for use in light-duty vehicles and trucks, and those for use in heavy-duty vehicles.
  • Light-duty vehicles and trucks are defined by the Environmental Protection Agency as passenger cars capable of seating twelve passengers or fewer, and light-duty trucks and all other vehicles under 8,501 pounds gross weight. This category includes most cars and pick-up trucks, mini-vans, and some special purpose vehicles.
  • Heavy-duty vehicles are defined as all vehicles over 8,500 pounds gross weight. Heavy-duty vehicles are, typically, trucks, buses, vans and recreational vehicles.
  • diesel engine finds application in industrial settings such as storage facilities and underground mines, many of which have only limited ventilation. And, diesel engines find further significant utilization in diesel locomotives; industrial applications such as fork lift engines, auxiliary engines on large vehicles, generator and pump service, and in logging, mining, quarrying and oil field operations, as well as well-drilling equipment; construction applications, such as use in bulldozers, motor graders, tractors, scrapers, rollers and loaders; and agricultural applications, such as powering agricultural equipment.
  • industrial applications such as fork lift engines, auxiliary engines on large vehicles, generator and pump service, and in logging, mining, quarrying and oil field operations, as well as well-drilling equipment
  • construction applications such as use in bulldozers, motor graders, tractors, scrapers, rollers and loaders
  • agricultural applications such as powering agricultural equipment.
  • diesel engine exhaust (unlike that of gasoline engines) is relatively clean in respect of unburned hydrocarbon- and carbon monoxide-content, several significant difficulties are attendant upon use of the diesel engine. They stem essentially from the fact that diesel engine exhaust contains undesirably large amounts of solid particulate matter, for instance, in amounts at least thirty to fifty times greater than amounts present in the exhaust of a gasoline engine.
  • Typical solid particulate matter from diesel engine exhaust is made up of small, solid, irregularly shaped particles which are agglomerates of roughly spherical subunits.
  • the particles often have high molecular weight hydrocarbons absorbed on their surfaces, and also may have a liquid coating; frequently, the particulate matter is a complex mixture of pure carbon and hundreds of organic compound.
  • the particulate is often extremely fine and light with a flour-like consistency. Size distribution ranges from very small single particles of about 0.01 microns to relatively large clusters in the range of 10-30 microns.
  • the particles have a bulk density of 0.075 g/cm3 and have a surface area of 100 m2/g.
  • the nature of solid particulate matter emitted from turbo-charged diesel engines is somewhat different from that of naturally aspirated diesel engines, the former tending to be smaller in size with much lower levels of retained organic compounds.
  • the Environmental Protection Agency has proposed a standard for particulate matter emission from diesel-powered light-duty vehicles of 0.6 g/mile, beginning with the 1987 model year; the agency has further proposed (for enforcement beginning with the 1990 model year) a standard for such emissions from diesel-powered heavy-duty vehicles of 0.25 g/bhp-hr (brake horsepower hour).
  • Acceleration smoke is that generated during vehicle acceleration. It is caused by a higher-than-desired fuel/air ratio and usually manifests itself as a short-duration, black puff. Lugdown smoke is generated during operation under a heavy load, for instance, during hill-climbing. It can conveniently be considered as full-load, steady-state smoke. Manufacturers compensate for these difficulties by mechanically limiting the amount of fuel injected under conditions at which the emissions are generated. Thus, smoke reduction is promoted at the cost of lost performance.
  • thermal in-stream oxidation techniques require the provision to the exhaust stream of large amounts of heat energy which is typically unrecoverable.
  • Catalytic in-stream oxidation requires devising a suitable means for introducing catalyst material into the exhaust stream, and preliminarily identification of appropriate catalyts, both difficult problems which to date have defied solution.
  • particulate loading is an irreversible process insofar as once loading or clogging has reached a certain point, the filter element must be discarded and replaced since the initial restriction cannot be restored; for such filter elements, cleaning is ineffective. Even if clogging is not allowed to proceed to irreversibility, its occurrence leads to choking off of the exhaust flow through the filter. Since to be effective the filter must be positioned in the exhaust stream, filter-clogging thus tends to increase the pressure differential across the filter element and impede the exhaust operation - which detrimentally effects operation of the diesel engine. Accordingly, it is necessary, if filtration is to be a practical solution, to remove solid particulate matter which clogs exhaust flow filtering elements, i.e., regenerate the filter.
  • filter-regeneration is central to the above-mentioned filtration techniques. But, while they address filter-regeneration, those techniques do not make it commercially attractive. For example, thermal and catalytic oxidation of filter-trapped particulate matter to regenerate the filter is problematical inasmuch as the space-, cost- and energy consumption-requirements which accompany them are substantial. These filtration techniques are no more acceptable than the direct, in-stream oxidation techniques which do not make use of filters.
  • DE-C-664371 discloses an exhaust filter for an internal combustion engine wherein valves are provided upstream and downstream, respectively, of the filter material.
  • the valves are coupled together for movement of each valve between two positions thereof. In a first position of each valve exhaust gases are caused to flow through the filter in a first direction, whilst in a second position of each valve the gases flow in the reverse direction to expel deposited soot from the filter.
  • a method which removes solid particulate matter from the exhaust of a diesel engine and which comprises passing the engine's exhaust flow through at least a part of a filter means to trap solid particulate matter initially contained in the exhaust, thereby to remove solid particulate matter from the exhaust flow, intermittently interrupting the exhaust flow through at least said part of the filter means, and backflushing at least said part of the filter means, during said interruption, by passing a backflush fluid through said part of the filter means in the reverse direction to that of the exhaust flow, characterised in that the method further includes creating a zone of reduced pressure on the upstream side of said part of the filter means or a zone of increased pressure on the downstream side of said part of the filter means and using said zone in the generation of at least one fluid pressure pulse of a backflush fluid of sufficient power to effect dislodgement of solid particulate matter from said part of the filter means, thereby regenerating said part of the filter means.
  • a diesel engine fitted with apparatus for carrying out the method of Claim 1 comprising filter means which is positioned to intercept the engine's exhaust flow and which traps solid particulate matter contained initially in the exhaust when that exhaust flows through at least a part of said filter means, thereby to remove said matter from the exhaust flow, means for intermittently interrupting the exhaust flow through at least said part of the filter means, and means for passing backflush fluid through at least said part of the filter means in the reverse direction to that of said exhaust flow during said interruption, characterised in that means are provided for creating a zone of reduced pressure on the upstream side of said part of the filter means or a zone of increased pressure on the downstream side of said part of the filter means and means are provided for using said zone in the generation of at least one fluid pressure pulse of a backflush fluid of sufficient power to effect dislodgement of solid particulate matter from said part of the filter means, thereby regenerating said part of the filter means.
  • the filter means is a single filter zone.
  • the present method and apparatus embodiments result in a reduction of solid particulate emission levels in diesel engine exhaust to an insignificant level; generally, 90% or more of the solid particulate emissions are removed, and particulate emissions are well under maximum emission levels proposed for implementation in the foreseeable future. This obviates the need to suppress potential power output of the engine in order to reduce emission levels; hence, a significantly increased utilization of the diesel engine's potential power output is enabled. Furthermore, the present invention provides a method and apparatus for controlling solid particulate emission which are direct, simple, relatively inexpensive and efficient through the use of widely available filtration materials and the elimination of the need to introduce large amounts of thermal energy, catalytic agents and the like into the filtering system.
  • the present invention through employment of pulsed backflushing, effects a substantially complete regeneration of the filter material utilized. This confers a significant benefit inasmuch as steady deterioration of the filter material due to irremediable long-term clogging effects, experienced when employing continuous backflushing, is eliminated and high filtration efficiency is maintained (thereby improving in-use performance and prolonging life expectancy of the filter). Also, and significantly, the present invention's employment of pulsed backflushing to regenerate the filter material, and the concommitant recycling of trapped solid particulate matter to the engine for combustion, actually result in a synergistic increase in the efficiency of incineration of that solid particulate matter vis-a-vis the efficiency of incineration of recycled solid particulate emissions when employing continuous backflushing. The instant invention is, therefore, a substantial technical and commercial advance.
  • Fig. 1 is a perspective view of a "ceramic honeycomb" filter element suitable for practicing the invention.
  • Fig. 2 is a schematic view of several individual passages within the filter element of Fig. 1.
  • Fig. 3 is a schematic view of one embodiment of the invention, namely, a diesel engine exhaust gas filter arrangement employing a single filter zone.
  • Fig. 4 is a curve showing the results of filter regeneration with the present invention.
  • Fig. 5 illustrates another embodiment in accordance with the present invention.
  • Fig. 6 is a schematic illustration of yet another embodiment of the invention.
  • Fig. 7 is a schematic illustration of an alternative embodiment of the invention in which pulsed backflushing is carried out with compressed air.
  • Fig. 8 is a schematic illustration of still another alternative embodiment of the invention in which two filter zones are employed.
  • the present invention is suitable for use in conjunction with both naturally aspirated and turbo-charged diesel engines of all sizes, but particularly with larger turbo-charged diesel engines utilized in heavy-duty vehicles, such as trucks, buses and the like, or in heavy industrial applications of the sort in which solid particulate emissions are especially high and especially intolerable due to poor ventilation or the like.
  • filtering methods and apparatus which involve a filter element that irreversibly (even if gradually) clogs to a level beyond that at which the filtration is compatible with effective engine operation, or the utilization of which result in the collection of solid particulate emissions elsewhere in the system until efficient operation of the engine is foreclosed, are not capable of sufficiently long-term operation to make them feasible solutions to the pollution problems discussed hereinabove.
  • the desideratum is to achieve equilibrium, i.e., a condition in which the amount of particulate emission from the engine is equivalent to an amount which is disposed of in a manner minimizing atmospheric pollution to the greatest degree possible.
  • Pollution minimization in accordance with the instant invention is accomplished by returning the solid particulate matter (except for the amount which accumulates in the system itself) to the engine for combustion (incineration).
  • design choices made in the course of implementing utilization of the invention will be geared toward maintaining the particulate emission inventory in the system at a feasibly low level and maximizing the amount of particulate emissions returned to the engine and there incinerated.
  • Suitable materials for filtering the exhaust stream in accordance with the invention are ceramic honeycomb, sintered metal particles, coated and uncoated metal mesh, ceramic fiber, ceramic foam, and packed beds.
  • ceramic honeycomb and sintered metal particle materials act as surface filters inasmuch as particles larger than the effective pore size of the honeycomb are normally collected on its upstream surface.
  • the other four filter media can be considered to function as depth filters because particle removal is not limited to the surface, but is continuous throughout part or all of the filter material's thickness or depth.
  • ceramic honeycomb traps In a ceramic honeycomb filter solid particles larger than the approximate mean pore size of the material are intercepted at the material's surface and prevented from passing through the material. As particles collect on the surface, the effective pore size is reduced which, in turn, leads to an increased efficiency as smaller sized particles are collected.
  • ceramic honeycomb traps have three zones of activity: first, a period of relatively rapid back pressure increase, most likely resulting from early pore plugging and initial cake formation on the upstream surface of the filter material; second, a prolonged period characterized by a relatively constant loading slope; finally, a shorter period during which back pressure again increases rapidly, probably due to complete plugging of many cells.
  • the leading one inch or so of the filter material when used in a typical filter assembly (see Fig.
  • Dislodgment of trapped solid particulate matter in accordance with the invention is preferably accomplished in the first or early second stage.
  • design of the ceramic honeycomb filter to optimize air flow within each channel of that filter element in order to distribute the loading more evenly does, in certain embodiments, increase the effectiveness of dislodgment and/or the time period which can be permitted to elapse between dislodgment events.
  • Sintered porous metal filter materials are advantageous in that they exhibit the structural integrity, corrosion resistance and temperature resistance required in certain embodiments of the invention. These materials are made typically by precompacting and then sintering stainless steel, nickel-base and other types of alloy metal powders. They are commercially available, for instance from Mott Metallurgical Corporation, and are well-adapted to regeneration (i.e., cleaning) in accordance with the present invention. Their "re-entrainment" characteristics can be highly useful in removing trapped particles with a relative minimum of difficulty.
  • the primary trapping mechanisms are impaction and diffusion. That is, during operation larger particles collide with the filaments of the mesh or fiber material and adhere to filament surfaces, or to particles already collected on those surfaces. Additionally, some smaller particles migrate by diffusion to the surface of the mesh or fiber material or to previously collected particles, and are also retained in the filter.
  • Mesh and fiber traps of this sort are advantageous in that the back pressures attendant upon their use are relatively low. While their tendency to exhibit a "blowoff" phenomena - that is, a reentrainment in the exhaust stream of previously collected particles - can be somewhat disadvantageous, its controlled occurrence operates, in certain embodiments of the present invention, to the advantage of the invention's practitioner as controlled reentrainment is one of the objects of the invention.
  • metal mesh filter material is coated with activated alumina which provides a highly porous surface structure of large surface area. Additionally, the porous surface tends to disrupt boundary layer flow thereby encouraging diffusion to the mesh filament. The foregoing result in increased collection efficiency and holding power.
  • Ceramic foam filter materials such as silica foam materials, are also useful. These materials provide a three-dimensional, open pore network which collects solid particulate matter efficiently.
  • the main trapping mechanisms are interception and diffusion. In general, trapping efficiency increases as the number of cells per linear inch and depth increases. Pressure drop across the ceramic foam filter increases with cell number and depth, but substantially decreases with increasing cross-sectional area for a given volumetric flow rate.
  • Dislodgment of trapped particles in accordance with the present invention is, in many instances more difficult when employing a ceramic foam material; however, in some embodiments, this difficulty is more than offset by the decreased back pressure attendant upon use of ceramic foam material in comparison with ceramic honeycomb material, due to the fact that cell size in the ceramic foam materials is often larger than the pore size in ceramic honeycomb structures.
  • Granular bed filters lend themselves to practicing of certain embodiments of the invention. They are particularly interesting for their capacity to function either in a stationary or fluidized mode. It follows that the granular bed can be operated in a stationary mode during loading or trapping to enhance collection efficiency, and then be operated in a fluidized mode during cleaning to enhance dislodgment and reentrainment. This benefit is a result of the fact that penetration in a moving bed is usually significantly higher than penetration in an otherwise equivalent stationary bed, the increase being attributable to better reentrainment through mechanical agitation in the fluidized mode.
  • collection efficiency of a stationary granular bed is increased by the intergranular deposits in the bed, that is solid particles which become interstitially lodged during filtering; the bed operates as a graded media filter, larger particles typically being collected on granules at the bed's surface and smaller particles collected within the bed's pores by an increasingly dense deposit.
  • Shallow beds are favored because they can be designed to provide high collection efficiency with relatively low back pressure and easy dislodgment and reentrainment.
  • An especially preferred filter material is a ceramic honeycomb unit with parallel channels running its entire length.
  • the cells are advantageously square in shape, but are suitably otherwise configured to be circular, elliptical, etc.
  • the ceramic filter unit is suitably fabricated of a porous cordierite (2MgO-2Al2O3-5SiO2), but is also acceptably made of any other ceramics, such as mullite, alumina, forsterite, aluminum titanate, mullite and aluminum titanate, spinel, zirconia and spinel, calcia partially stabilized zirconia, and alumina and silica.
  • Units fabricated of the foregoing materials which are suitable for the invention typically have physical features such as cell density, porosity, mean pore size, coefficient of thermal expansion, and compression strength, corresponding to those of commercially available units of such materials employed in filtering particulate from diesel engine exhaust.
  • the overriding requirements are that the material has the necessary mechanical strength, chemical resistance, thermofracture resistance, and melt resistance to survive effectively in the hostile environment presented by diesel engine exhaust.
  • Fig. 1 there is depicted one type of ceramic honeycomb filter unit suitable for practicing of the present invention.
  • the unit 10 has a monolith face 12. On the face, openings 14 alternate with solid ceramic plugs 16 to form a checkerboard arrangement. The openings permit ingress to and egress from parallel channels which extend the entire length of the unit. The channels terminate at the opposite end of the unit (not shown), and are blocked at that end by ceramic plugs so as to create a set of blind passages.
  • the opposite end of the filter unit is also made up of alternating pores and ceramic plugs. The pores in the opposite end permit ingress to and egress from a corresponding parallel set of channels running the entire length of the unit and terminating in ceramic plugs 16 in face 12.
  • the ceramic channels opening at the opposite end of the filter unit 10 provide another set of parallel blind passages, and are situated in the filter unit to alternate with the blind passages which open on face 12.
  • Fig. 2 schematically depicts channel arrangement 20 of the type shown in Fig. 1.
  • Particulate laden exhaust 22 is directed at the upstream face of the unit 24.
  • the exhaust enters blind channels 26 through openings 28 in the upstream face of the unit.
  • Channels 26 are blocked at the downstream face 30 by ceramic plugs 32.
  • openings 34 permit ingress to and egress from channels 36.
  • Those channels are closed at the upstream face 24 by ceramic plugs 38.
  • Channels 26 and 36 are separated by common walls 40. These common walls are sufficiently porous to permit passage of exhaust gas; however, the wall pores are sufficiently small to prevent passage of the vast majority of solid particulate matter in the exhaust.
  • a backflush fluid pulse is passed through such unit in a direction opposite that of the aforementioned exhaust.
  • the backflush fluid pulse first encounters what is normally downstream end 30 of the unit, passes through openings 34 and into channels 36, diffuses through common walls 40, dislodges particles 42 from the common walls in channels 26, entrains those particles and carries them along channels 26 through openings 28 and out of the trap. In this manner, the trap is cleaned, that is regenerated.
  • the collection efficiency of the trap must be balanced against, and not accomplished at the expense of, excessive introduction of back pressure in the exhaust system.
  • the time period allowed to elapse between filter unit cleanings must not be so great as to permit the accumulation of a layer of solid particulate matter on the filter material surface so as to increase the pressure drop to an unacceptable level.
  • increasing the pressure drop across the filter unit is accompanied by increasing back pressure in the exhaust system. Backpressure has a direct and detrimental effect on the operation of the invention, and its occurrence should be minimized whenever possible.
  • Pressure drop can be maintained at lower levels through the choice of appropriate design features. Illustratively, it is a function of cell geometry, wall properties and volume of a ceramic filter unit. Those features are advantageously set such that a balance is struck between minimizing pressure drop and maintaining the required filter efficiency.
  • Burning collected soot off the filter places a greater physical demand on the filter than the conditions it is normally subjected to in the course of filtering exhaust. That is to say, burning of accumulated soot and other solid particulate matter during regeneration releases a large amount of energy and generates a rapid temperature rise. Moreover, that temperature rise is not necessarily evenly distributed throughout the filter unit, thereby setting up thermal gradients in both radial and axial directions. Additionally, excessive buildup of solid particulate matter can result in release of an excessively large amount of energy upon burning, thus subjecting the material (e.g. ceramic material) of the filter unit to temperatures exceeding its melting point.
  • the quest for achievement of acceptable operating characteristics and filter life using certain conventional regeneration processing is prohibitively impeded, if not defeated, by the necessity to strike a balance among the competing considerations of filtration time between regeneration cycles, filter pressure drop, and degree of particulate loading.
  • the separation forces exerted by pulsed backflush fluid must be in excess of the forces by which solid particulate matter adheres to the filter material.
  • movement of the backflush fluid stream in the immediate vicinity of trapped particulate matter is significant.
  • the particle in order to initiate particle movement the particle must receive energy from an external source, for instance from the impact of another particle or object or from drag forces of the moving backflush fluid stream past the exposed profile of the particle.
  • the backflush fluid pulse must be composed of a sufficient amount of fluid colliding with and passing through the filter unit at a sufficient velocity to dislodge trapped particles.
  • the pulse can be viewed as a wave; the pulsed backflushing must be of sufficient power (i.e. a sufficient amount of energy must pass by some point in the filter per unit time) to dislodge trapped particles.
  • the change in pressure at any one point in the filter unit due to the passage of the wave therethrough should occur in an amount of time which is sufficiently short that the fluid pulse is capable of dislodging trapped particles.
  • Pulsed backflushing fluid flow is suitably generated in any convenient manner which lends itself to utilization in the particular environment to which the invention is applied.
  • the fluid is not necessarily limited to same.
  • the fluid is suitably any one which can be passed through the filter material so as to dislodge trapped particles, and the presence of which does not otherwise interfere with or detrimentally affect the operation of the engine system.
  • Oxygen, or an inert gas such as nitrogen, is an example of a suitable alternative fluid.
  • the backflush fluid pulse is generated by inducing a vacuum condition, or at least very low pressure, in the exhaust system on the upstream side of the trap, and then effecting a sudden release of backflush fluid into the vacuum or low pressure volume such that a sufficient mass of the backflush fluid rushes through the trap at high velocity (in a short time period) to dislodge trapped particles.
  • An especially advantageous manner for accomplishing this is to employ the intake pull of the engine to draw down the pressure on the upstream side of trap or filter unit.
  • a valve in the exhaust system is actuated, and moved into the open position, in response to the attainment of a suitably low pressure; the valve's opening causes ambient air or other backflushing fluid to be drawn through the filter unit or trap in a direction opposite to that of the exhaust flow (the exhaust flow has of course been interrupted during this backflushing cycle) by the low pressure conditions on the upstream side of the filter unit or trap.
  • the backflush fluid pulse can be a burst or surge of pressurized fluid, for instance compressed gas (illustratively, air).
  • compressed gas for instance, air
  • the pulse is acceptably drawn from a pressurized container or other suitable source; conveniently compressed air drawn from the hydraulic or turbo-charging system of a diesel-powered vehicle will do.
  • the compressed gas pulse is injected into the exhaust system on the downstream side of the filter unit or trap so as to flow through the trap in a direction which is the reverse of that taken by the exhaust flow during normal filtering operations. Again, the compressed gas pulse is injected into the system during interruption of normal exhaust flow.
  • the compressed gas pulse must be of sufficient mass and traveling at sufficient velocity to dislodge the particles trapped in the filter unit.
  • the backflush fluid pulse employed to dislodge trapped solid particulate matter is also utilized as an entrainment vehicle, i.e. a carrier, for the dislodged particulate matter in order to transport same back to the diesel engine.
  • the backflush fluid pulse is air, the oxygen component of which is sufficient, upon reaching the engine along with the particles entrained in the air, to enable the incineration (oxidation) of those particles.
  • a diesel engine exhaust filtering arrangement 60 as schematically depicted in Fig. 3 was constructed to demonstrate the invention.
  • a Mack diesel engine 62 having a solid particulate emission level of about 1 gm/min. under normal steady-state operational conditions was connected by lines 78, 66 and 68 to trap 64.
  • the trap was a ceramic filter having a single filter zone which was positioned across the engine's exhaust stream flowing through lines 68 and 70.
  • the filter unit was fabricated of cordierite and had the following features: mean pore size - 12 mm; cell density - 100 cells per in2; average wall thickness - 17 mils; porosity - 52/56%; coefficient of thermal expansion - 9.5/11.0 x 10 ⁇ 7in/in/°C 925-2000°C); and compressive strength - 1130 psi, 250 psi, 15 psi along the longitudinal, lateral, and diagonal areas, respectively. Solid particulate matter contained initially in the exhaust was trapped in the filter zone when that exhaust flowed through such zone.
  • Lines 70 and 72 were connected to provide a path from the downstream end of the filter means to main exhaust line 74 leading to the atmosphere.
  • Line 78 was connected between the engine's exhaust port and main exhaust line 74.
  • Intake line 76 conducted air from the ambient atmosphere to the engine 62.
  • Line 68 connected the upstream side of the trap 64 and the intake line 76.
  • Valve 80 was positioned across line 66 at a location intermediate the port from which exhaust is emitted from the engine and line 66's connection with line 68. The valve was movable between an open state permitting flow through line 66 and a closed state interrupting flow.
  • Valve 82 was positioned across line 72 between main exhaust line 74 and the connection of line 70 with line 72. This valve too was movable between an open state permitting flow through line 72 and a closed state interrupting flow.
  • Valve 84 was positioned across line 78 between main exhaust line 74 and the connection between lines 78 and 66. This valve was likewise movable between an open state permitting flow through line 78 and a closed state interrupting flow.
  • Valve 86 was positioned across intake line 76, and was movable between an open state permitting flow through line 76 and a closed state interrupting flow along said intake path.
  • Valve 88 was positioned across line 68, and was movable between an open state permitting flow through line 68 and a closed state interrupting flow.
  • An aluminum foil diaphragm 92 was positioned across the end of line 70.
  • the thickness and strength of the foil diaphragm were selected so that it would rupture when one side of it was subjected to atmospheric pressure and the other side to a reduced pressure condition resulting from the intake pull of the engine.
  • Valve 90 was positioned across line 70 between diaphragm 92 and the connection of the line 70 with line 72. The valve was movable between an open state permitting flow through line 70 and a closed state interrupting flow.
  • Sampler 94 (an isokinetic sampler) was connected to line 78 for the purpose of obtaining a profile of solid particulate emission from the engine before and during pulsed backflushing.
  • Sampler 96 (also an isokinetic sampler) was connected to line 70 for the purpose of ascertaining the amount of solid particulate matter passing through trap 64, and thus into the atmosphere.
  • Pressure sensor 98 was connected to line 68 for the purpose of determining when a pressure rise (signalling the passage of a backflush fluid pulse on its way to engine 62) occurred in the line.
  • valves 80, 82 and 86 were maintained in the open state to permit ambient air to flow to the engine through line 76, and exhaust flow from the engine through lines 78, 66 and 68, the trap 64, lines 70 and 72 and the main exhaust line 74. Valves 88, 90 and 84 were maintained in the closed state. It can readily be appreciated, of course, that the approximate ten minute filtering period is only an example; periods of longer and shorter duration are suitable in this and other embodiments of the invention depending on the configuration of the system, type and size of trap used, size and nature of the engine, and like considerations.
  • valves 84 and 88 were opened and valves 82 and 80 were closed to redirect exhaust through line 78.
  • valve 90 was opened, and then valve 86 closed, the engine's intake pull thus being redirected through line 68, trap 64 and line 70.
  • the intake pull of the engine drew down the pressure in lines 68 and 70, and when sufficiently low pressure was achieved the foil 92 ruptured. That rupture caused a pulse of ambient air to be pulled through line 70, trap 64, line 68 and line 76, into engine 62. When the pulse passed through the trap it dislodged solid particulate matter therein.
  • the particulate was entrained in the backflush air pulse and also carried to the engine 62.
  • sensor 98 ascertained passage of the pulse in line 68, a signal was generated (by conventional means not shown for simplicity) in response to which the valves were returned to their normally open and closed states (as described in the preceding paragraph).
  • the system was operated for approximately 1040 minutes during which 100 cycles were completed, the cycles generally comprising about 10 minutes of passage of the engine's exhaust through trap 64 and then about ten to twenty seconds during which exhaust was redirected through line 78 and ultimately the trap was cleaned by a backflushing pulse of ambient air.
  • upstream pressure engine backpressure
  • differential pressure would increase somewhat during each (approximately) ten-minute period of exhaust filtration (pulsed backflushing is represented on the strip chart by the portions of the curve at which pressure drops precipitously).
  • the maximum backpressure and pressure differential reached during each succeeding cycle would generally be higher than the last, until one backflushing pulse would dislodge an unusually large number of particles and thus be particularly effective in cleaning the filter and restoring a low pressure differential.
  • a recurrent pattern of such behavior indicates the attainment of a steady-state condition in which the system is not gradually deteriorating due to gradually increasing and irreversible filter loading, but rather is continually regenerated so as to remain in an equilibrated and effective state such that filtration can be continued indefinitely.
  • Fig. 5 is a schematic depiction of a diesel engine exhaust emission filtration system 100 actually constructed to demonstrate the invention.
  • a Cummins diesel engine 102 having a solid particulate emission level of about 1.1 g/min. was connected by lines 106 and 108 to trap 104.
  • the trap was a ceramic filter (the same filter unit is employed for example 1) having a single filter zone which was positioned across the engine's exhaust stream flowing through lines 106 and 108. Solid particulate matter contained initially in the exhaust was trapped in the filter zone when that exhaust flowed through the zone.
  • trap 104 and line 110 were connected to provide a direct path to the atmosphere.
  • Intake line 112 was connected to the engine 102 and conducted air from the ambient atmosphere to the engine.
  • Line 108 was connected between the upstream side of trap 104 and the intake line 112.
  • Valve 114 was positioned across line 108, and was movable between an open state permitting flow through line 108 and a closed state interrupting flow.
  • Valve 116 was positioned across intake line 112, and was movable between an open state permitting flow through that line and a closed state interrupting flow.
  • An aluminum foil diaphragm 118 was positioned across line 108 between valve 114 and the connection of lines 108 and 112. The thickness and strength of the foil diaphragm were selected so that it would rupture when one side of it was subjected to a reduced pressure condition resulting from the intake pull of the engine.
  • the engine was run for 91 cycles of the type described in connection with example 1 - i.e., each cycle comprising a relatively long period during which the engine's exhaust was directed through the trap 104 (usually about ten minutes but sometimes up to one-half an hour or more) and a shorter period (about .2 seconds) during which exhaust flow through the trap was interrupted to accommodate regeneration.
  • valve 116 was maintained in the opened state and valve 114 was maintained in the closed state, thereby causing the engine's exhaust to flow through lines 106 and 108 to the upstream side of trap 104, through the trap and through line 110 for release into the atmosphere.
  • valve 114 was opened and valve 116 closed, the engine's intake pull thus being redirected through line 108.
  • the intake pull of the engine drew down the pressure in line 108, and when sufficiently low pressure was achieved the foil 118 ruptured.
  • the rupture caused a pulse of ambient air to be pulled through line 110, trap 104, and lines 108 and 112, into engine 102.
  • the pulse passed through the trap it dislodged solid particulate matter therein.
  • the particulate was entrained in the backflush air pulse and also carried to engine 102.
  • Sampler 122 (isokinetic sampler) was connected to line 110 for the purpose of ascertaining the amount of solid particulate matter passing through trap 104, and thus into the atmosphere.
  • Sensor 120 (a pressure sensor) was connected to line 108 for the purpose of determining when a pressure rise (signaling the passage of a backflush fluid pulse on its way to engine 102) occurred in the line.
  • sensor 120 ascertained passage of the pulse in line 108, a signal was generated (by conventional means not shown for the sake of simplicity) in response to which the valves were returned to their normally opened and closed states.
  • Sampler 122 indicated that trap 104 was effective in removing 93 to 96% of solid particulate emission from the filtered exhaust during the first 54 cycles. Since solid particulate emission is not released from the system in any other manner, it is clear that the system was at least 90% effective in removing solid particulate emission from diesel engine exhaust. In succeeding runs trap efficiency decreased to about 85%; this was viewed as an aberration of the trap material itself and not of the invention. Accordingly, later results can be discounted. However, even including those questionable data, the average filtering efficiency was at least 88.9% on average.
  • FIG. 6 Yet another embodiment suitable for commercial application is illustrated in Fig. 6.
  • a diesel engine 130 is connected to trap 132 by line 134.
  • Intake line 136 leads from the ambient atmosphere to engine 130, to provide ambient air for combustion within the engine.
  • Line 138 is connected to line 134 and to line 136 to provide an alternate flow path around the engine.
  • Valve 140 is positioned across line 136, and is movable from an open position permitting flow through the line, to a closed position interrupting flow.
  • Valve 142 is positioned across line 134, and is movable between an open position permitting flow through the line and a closed position preventing such flow.
  • Line 138 is connected to line 136 between valve 140 and the engine, and is connected to line 134 between valve 142 an the trap 132.
  • the pressure drop across trap 132 is monitored by a conventional sensor (not shown for the sake of simplicity) sensor.
  • a conventional sensor not shown for the sake of simplicity
  • valves 140 and 142 - which are normally open to permit intake flow to the engine and transportation of the exhaust stream to the trap for filtration - are closed simultaneously. This can be accomplished by actuating a solenoid on each valve by means of a differential pressure switch placed across the filter.
  • Valve 144 is positioned across line 138, and is movable between an open position permitting flow through line and a closed position preventing flow.
  • valves 140 and 142 are closed the engine quickly reduces the pressure in the volume of line between the engine and valve 144. During this time, exhaust from the engine is accumulated in the volume of line between the engine and valve 142.
  • Valve 144 is an automatic valve that opens when the pressure differential across it reaches a predetermined value.
  • valve 144 opens in response to the drawing down of pressure by the engine in line 138 (valve 144 opens very quickly) ambient air flows through line 146, trap 132, line 134 line 138 and line 136, and eventually to the engine, in a direction opposite that of normal exhaust flow.
  • This surge of gas constitutes a pulsed backflushing of trap 132, which surge carries particles dislodged from the trap back to the engine for incineration.
  • Valves 140 and 142 open in response to valve 144's automatic opening, after a suitable delay. Valve 144 automatically closes after the pressure differential across it is removed, and the system is restored to its original condition.
  • the entire cleaning sequence is completed in less than one second, and preferably less than 0.25 seconds. Indeed, regeneration periods of no more than one second, and preferably no more than 0.25 seconds, are advantageously employed in many other embodiments of the invention also.
  • Example 2 can be modified by appropriate substitution of automatic valve sequencing as described in connection with the embodiment depicted in Fig. 6. This would of course eliminate the necessity of using a foil diaphragm, which is an expedient adopted for experimentation only. It is also clear that, due to the benefits deriving from pulsed backflushing, the filter means of the claimed invention need not be limited to only one filter zone. Several of those advantages accrue even when two or more filter elements (or two or more filter zones of one element) are employed, although use of only one filter zone affords clear commercial advantages.
  • a filtered system 150 includes diesel engine 152 connected to trap 154 by line 156.
  • Intake line 158 leads from the ambient atmosphere to engine 152, to provide ambient air for combustion within the engine.
  • Line 160 is connected to line 156 and to line 158 to provide an alternate flow path around the engine.
  • Valve 162 is positioned across line 158, and is movable from an open position permitting flow through the line, to a closed position interrupting flow.
  • Valve 164 is positioned across line 156, and is movable between an open position permitting flow through the line and a closed position preventing such flow.
  • Line 160 is connected to line 158 between valve 162 and engine 152, and is connected to line 156 between valve 164 and trap 154.
  • the pressure drop across trap 154 is monitored by a conventional sensor (not shown for the sake of simplicity).
  • a conventional sensor not shown for the sake of simplicity.
  • valves 162 and 164 - which are normally open to permit intake flow to the engine and transportation of the exhaust stream to the trap for filtration - are closed simultaneously. This can be accomplished by actuating a solenoid on each valve by means of a differential pressure switch placed across the filter. After a suitable but short delay a pulse of compressed air is released from source 170 and injected through line 168 into line 166, through trap 154 and lines 156, 160 and 158 into engine 152.
  • This surge of air constitutes a pulsed backflushing of trap 154, which surge carries particles dislodged from the trap back to the engine for incineration. During this time, exhaust from the engine is accumulated in the volume of line between the engine and valve 164.
  • Valves 162 and 164 open a suitable time after injection of the compressed air pulse.
  • the entire cleaning sequence is completed in less than one second, and preferably less than 0.25 seconds.
  • a filtered system 180 includes diesel engine 182 connected alternately to trap 184 by lines 192 and 198 and to trap 186 by lines 192 and 202.
  • Intake line 188 leads from the ambient atmosphere to engine 182, to provide ambient air for combustion within the engine; valve 190 is positioned across line 188 and is movable between open and closed states permitting and interrupting flow, respectively.
  • Line 194 is connected to line 188 and to line 202 to provide an alternate flow path around the engine.
  • Line 192 connects with valve 214, and is movable to direct flow into either line 198 or 202 while closing off flow to the other.
  • Line 200 connects to valve 212, which is movable to direct flow from either line 198 or 204 into line 200, and to close off flow from the line not selected.
  • Line 194 is connected to line 188 between valve 190 and the engine. The pressure drop across traps 184 and 186 is monitored by conventional sensors (not shown for the sake of simplicity).
  • valves 214 and 212 - which have been oriented to permit transportation of the exhaust stream to trap 184 for filtration and drawing of air through trap 186, lines 202, 204, 200 and 194, and line 188 back to the engine - are moved simultaneously.
  • the system is then set so that exhaust flows through lines 192 and 202 to trap 186, and then into line 208 to the atmosphere while flow from the atmosphere through trap 184, lines 198, 200 and 194, and line 188 back to the engine is permitted.
  • Periodically valve 190 is closed.
  • Valve 210 is positioned across line 200, and is movable between an open position permitting flow through line and a closed position preventing flow. When valve 190 is closed the engine quickly reduces the pressure in the volume of line between the engine and valve 210, which is normally closed.
  • Valve 210 is an automatic valve that opens when the pressure differential across it reaches a predetermined value.
  • valve 210 opens in response to the drawing down of pressure by the engine in line 194 (valve 210 opens very quickly) ambient air flows through line 206, trap 184, line 198, line 200 and line 194, and eventually (through line 188) to the engine.
  • This surge of gas constitutes a pulsed backflushing of trap 184, which surge carries particles dislodged from the trap back to the engine for incineration.
  • valve 210 When valve 190 is opened, valve 210 automatically closes after the pressure differential across it is removed, and the system is restored to its initial condition. The entire cleaning sequence is completed in less than one second, and preferably less than 0.25 seconds. In some embodiments each trap is cleaned by a plurality of such sequences.
  • valves 212 and 214 are operated to direct exhaust to trap 184 and permit backflushing of trap 186 in like manner. It can be readily appreciated from the foregoing example that numerous alternative systems containing a plurality of filter zones are configurable depending on the needs of the practitioner and his environmental constraints.
  • the particles are acceptably dislodged from the filter unit by a sonic wave generated by appropriate conventional apparatus.
  • the principal and basic criterion for such mechanical waves are that the filter unit must be subjected to a wave of sufficient power, that is of sufficiently high energy passing by any point within the filter unit in a selected unit of time, to dislodge the trapped particulate material. Waves which fulfill this requirement are suitable.
  • a method and apparatus which enable direct, simple, relatively inexpensive and efficient filtration of diesel engine exhaust to remove solid particulate matter. More specifically, the present method and apparatus embodiments result in a reduction of solid particulate emission levels in diesel engine exhaust to an insignificant level, i.e., filtering out of 90% or more of the particulate.
  • the present invention obviates the need for deliberate suppression of engine power, or reliance on other disadvantageous conventional filtration techniques, in order to reduce solid particulate exhaust emission.
  • the attainment of effective filtration of solid particulate matter from diesel engine exhaust along with a significantly increased utilization of the diesel engine's potential power output is a substantial advance in the art.

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  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Filtering Of Dispersed Particles In Gases (AREA)
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Claims (26)

  1. Procédé permettant d'éliminer une substance particulaire solide, des gaz d'échappement d'un moteur diesel et qui consiste à
       faire passer le courant des gaz d'échappement du moteur dans au moins une partie de moyens formant filtre afin de retenir la substance particulaire solide initialement contenue dans les gaz d'échappement, afin d'éliminer la substance particulaire solide du courant des gaz d'échappement,
       interrompre de façon intermittente le courant des gaz d'échappement traversant au moins ladite partie desdits moyens formant filtre, et
       exécuter un reflux au moins dans ladite partie des moyens formant filtre, pendant ladite interruption, en faisant passer un fluide de reflux dans ladite partie des moyens formant filtre dans la direction inverse à celle du courant des gaz d'échappement,
       caractérisé en ce que le procédé comprend en outre
       la création d'une zone de pression réduite sur le côté amont de ladite partie des moyens formant filtre ou une zone de pression accrue sur le côté aval de ladite partie des moyens formant filtre, et
       l'utilisation de ladite zone pour la production d'au moins une impulsion de pression d'un fluide de reflux ayant une puissance suffisante pour détacher la substance particulaire solide de ladite partie des moyens formant filtre, de manière à régénérer ladite partie des moyens formant filtre.
  2. Procédé selon la revendication 1, caractérisé par l'envoi du fluide de reflux à l'admission du moteur de manière que ladite substance particulaire solide puisse étre brûlée dans le moteur.
  3. Procédé selon la revendication 1 ou 2, caractérisé en ce que
       ladite zone est initialement séparée de ladite partie des moyens formant filtre, et
       ensuite ladite zone est mise en communication avec ladite partie desdits moyens formant filtre et ladite au moins une impulsion de pression fluidique est produite.
  4. Procédé selon la revendication 1, 2 ou 3, caractérisé en ce que ladite au moins une impulsion de pression fluidique est produite dans le fluide de reflux traversant au moins ladite partie des moyens formant filtre pendant ladite interruption.
  5. Procédé selon la revendication 4, caractérisé en ce que la ou chaque impulsion est produite par des moyens aptes à fermer momentanément l'admission du moteur diesel et produire de ce fait un tirage d'admission intense dans le moteur.
  6. Procédé selon la revendication 1, caractérisé en ce que ladite au moins une impulsion comprend une surcharge de fluide sous pression provenant d'une source extérieure, le fluide sous pression traversant au moins ladite partie des moyens formant filtre pendant l'interruption du courant des gaz d'échappement.
  7. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que le courant des gaz d'échappement est interrompu pendant une période atteignant jusqu'à une seconde.
  8. Procédé selon la revendication 7, caractérisé en ce que ladite période est égale à 0,25 seconde ou moins.
  9. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce qu'il consiste à faire passer le courant des gaz d'échappement dans pas plus d'une zone de filtrage située dans lesdits moyens formant filtre.
  10. Procédé selon l'une quelconque des revendications 1 à 8, caractérisé en ce qu'il consiste à faire passer le courant des gaz d'échappement dans une pluralité de zones de filtrage dans lesdits moyens formant filtre.
  11. Procédé selon l'une quelconque des revendications 1 à 8, caractérisé en ce qu'il consiste à faire passer le courant des gaz d'échappement à travers une pluralité d'éléments séparés de filtrage situés dans lesdits moyens formant filtre.
  12. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce qu'il consiste à faire passer le courant des gaz d'échappement à travers une structure de filtre céramique en nid d'abeilles, un matériau métallique fritté poreux, un treillis métallique, une fibre céramique, une mousse céramique ou un lit granulaire constituant lesdits moyens formant filtre.
  13. Procédé selon la revendication 12, caractérisé en ce qu'il consiste à faire passer le courant de gaz d'échappement à travers la structure de filtre céramique en nid d'abeilles formée de cordiérite et constituant lesdits moyens formant filtre.
  14. Moteur diesel équipé d'un dispositif pour la mise en oeuvre du procédé selon la revendication 1, le dispositif comprenant des moyens formant filtre (132; 154; 184; 186), qui sont disposés de manière à intercepter le courant des gaz d'échappement du moteur et retiennent une substance particulaire solide contenue initialement dans les gaz d'échappement lorsque ces derniers traversent au moins une partie des moyens formant filtre, de manière à éliminer ladite substance du courant des gaz d'échappement, des moyens (142;164;214) pour interrompre de façon intermittente le courant des gaz d'échappement traversant au moins ladite partie des moyens formant filtre, et des moyens (138;160;194,200,204,202,198) pour faire passer un fluide de reflux dans au moins ladite partie des moyens formant filtre dans le sens inverse de celui dudit courant des gaz d'échappement pendant ladite interruption,
       caractérisé en ce qu'il est prévu
       des moyens pour créer une zone de pression réduite sur le côté amont de ladite partie des moyens formant filtre ou une zone de pression accrue sur le côté aval de ladite partie des moyens formant filtre, et
       des moyens (140,144;162,170;210,190) pour utiliser ladite zone en vue de la production d'au moins une impulsion de pression d'un fluide de reflux présentant une puissance suffisante pour détacher la substance particulaire solide de ladite partie des moyens formant filtre, ce qui permet de régénérer ladite partie des moyens formant filtre.
  15. Moteur diesel selon la revendication 14, caractérisé en ce que les moyens (132;154;184;186) envoient le fluide de reflux à l'admission du moteur.
  16. Moteur diesel selon la revendication 14 ou 15, caractérisé en outre en ce que
       ladite zone est séparée initialement de ladite partie des moyens formant filtre; et
       lesdits moyens pour produire ladite au moins une impulsion de pression fluidique comprennent des moyens pour mettre en communication ladite zone avec ladite partie des moyens formant filtre.
  17. Moteur diesel selon l'une quelconque des revendications 14 à 16, caractérisé en ce que lesdits moyens pour produire au moins une impulsion de pression fluidique produisent au moins une impulsion dans le fluide de reflux traversant au moins ladite partie des moyens formant filtre pendant ladite interruption.
  18. Moteur diesel selon la revendication 17, caractérisé en ce que la ou chaque impulsion est produite par des moyens (86,88;116,118;140,144;162;190,210) aptes à fermer momentanément l'admission du moteur diesel et à produire de ce fait un tirage d'admission intense pour le moteur.
  19. Moteur diesel selon la revendication 17, caractérisé en ce que lesdits moyens de décolmatage du filtre produisent une impulsion qui est une surcharge d'un fluide sous pression délivré par une source extérieure (170) et qui traverse, pendant l'interruption du courant des gaz d'échappement, au moins ladite partie des moyens formant filtre.
  20. Moteur diesel selon l'une quelconque des revendications 14 à 18, caractérisé par des moyens pour interrompre le courant des gaz d'échappement pendant une durée atteignant jusqu'à une seconde.
  21. Moteur diesel selon la revendication 20, caractérisé en ce que ladite période est égale à 0,25 seconde ou moins.
  22. Moteur diesel selon l'une quelconque des revendications 14 à 21, caractérisé en ce que les moyens formant filtre comprennent une structure de filtre céramique en nid d'abeilles, un matériau métallique fritté poreux, un treillis métallique, une fibre céramique une mousse céramique ou un lit granulaire.
  23. Moteur diesel selon la revendication 22, caractérisé en ce que les moyens formant filtre comprennent une structure de filtre céramique en nid d'abeilles formée de cordiérite.
  24. Moteur diesel selon l'une quelconque des revendications 14 à 23, caractérisé en ce que les moyens formant filtre possèdent une seule zone de filtrage.
  25. Moteur diesel selon la revendication 14, comprenant un premier tuyau d'échappement (134) raccordant l'extrémité d'entrée des gaz d'échappement desdits moyens formant filtre (132) et une orifice, d'où sortent les gaz d'échappement provenant de la chambre de combustion du moteur, un tuyau d'échappement (146) raccordé à la sortie des gaz d'échappement desdits moyens formant filtre (132) et débouchant à l'atmosphère, un premier conduit d'admission (136) par lequel de l'air pénètre dans ladite chambre de combustion à partir de l'atmosphère ambiante, et un second conduit d'admission (138) raccordant le premier tuyau d'échappement (134) et le premier conduit d'admission (136), caractérisé par
       des premiers moyens formant soupape d'échappement (140) disposés dans le premier tuyau d'échappement (134) en un emplacement situé entre l'orifice d'où s'échappent les gaz d'échappement provenant de la chambre de combustion dudit moteur (130) et le raccordement du premier des tuyaux d'échappement avec le second tuyau d'échappement (138), lesdits premiers moyens formant soupape d'échappement (142) étant déplaçables entre un état ouvert permettant au courant des gaz d'échappement provenant du moteur de circuler dans ledit premier tuyau d'échappement (134), et un état fermé interrompant l'écoulement des gaz d'échappement en direction des moyens formant filtre (132);
       des premiers moyens formant soupape d'admission (140) disposés dans le premier conduit d'admission (136) de telle sorte que le second conduit d'admission (138) est raccordé au premier conduit d'admission (136) entre les premiers moyens formant soupape d'admission (140) et le moteur (130), lesdits premiers moyens formant soupape d'admission (140) étant déplaçable entre un état ouvert permettant une circulation depuis l'atmosphère ambiante en direction du moteur par l'intermédiaire dudit premier conduit d'admission (136), et un état fermé interrompant ledit écoulement dans ledit conduit d'admission (186);
       des seconds moyens formant soupape d'admission (144) disposés dans le second conduit d'admission (138), lesdits seconds moyens formant soupape d'admission (144) étant déplaçables entre un état ouvert permettant une circulation dans le second conduit d'admission (138), et un état fermé interrompant l'écoulement dans le second conduit d'admission (138), lesdits seconds moyens formant soupape d'admission (144) s'ouvrant en réponse à une différence de pression prédéterminée présente dans ces moyens, et se fermant en réponse à la suppression de ladite pression différentielle;
       lesdits premiers moyens formant soupape d'admission (140) et lesdits premiers moyens formant soupape d'échappement (142) étant normalement dans l'état ouvert pour permettre la circulation d'admission de l'air ambiant dans le premier conduit d'admission (136) et la circulation des gaz d'échappement provenant de la chambre de combustion du moteur dans le premier tuyau d'échappement (134), les moyens formant filtre (132) et le second tuyau d'échappement (146), et lesdits seconds moyens formant soupape d'admission (144) étant normalement situés dans l'état fermé;
       des moyens pour fermer de façon intermittente les premiers moyens formant soupape d'admission (140) et les premiers moyens formant soupape d'échappement (142) sensiblement simultanément pour rediriger le tirage d'admission dans le moteur dans le second conduit d'admission (138). créer ladite différence de pression prédéterminée et ouvrir lesdits seconds moyens formant soupape d'admission (144), de manière à produire une impulsion du courant d'admission traversant lesdits moyens formant filtre (132) et à détacher une substance particulaire solide dedits moyens formant filtre et l'entraîner en direction de l'admission du moteur pour qu'elle brûle dans ce dernier;
       des moyens pour ouvrir lesdits premiers moyens formant soupape d'admission (140) et lesdits premiers moyens formant soupape d'échappement (142) en réponse à la fermeture desdits moyens formant soupape d'admission (144) lors de la suppression de ladite pression différentielle.
  26. Moteur diesel selon la revendication 14, comprenant un premier tuyau d'échappement (192) raccordant l'extrémité d'entrée des gaz d'échappement desdits moyens formant filtre (184;186) et un orifice d'où sortent les gaz d'échappement provenant de la chambre de combustion du moteur, un second tuyau d'échappement (206;208) raccordé à la sortie des gaz d'échappement desdits moyens formant filtre (184;186) et débouchant à l'atmosphère, un premier conduit d'admission (188), par l'intermédiaire duquel de l'air pénètre dans ladite chambre de combustion à partir de l'atmosphère ambiante, et un second conduit d'admission (194,200,204,202) raccordant le premier tuyau d'échappement (192) et le premier conduit d'admission (188),
       caractérisé par
       des premiers moyens formant soupape d'admission (190) disposés dans le premier conduit d'admission (188) de telle sorte que le second conduit d'admission (194,200,204,202) est raccordé au premier conduit d'admission (188) entre les premiers moyens formant soupape d'admission (190) et le moteur, lesdits premiers moyens formant soupape d'admission (190) étant déplaçables entre un état ouvert permettant une circulation depuis l'atmosphère ambiante en direction du moteur dans ledit premier conduit d'admission (188), et un état fermé interrompant ladite circulation dans ledit premier conduit d'admission (188);
       des seconds moyens formant soupape d'admission (210) disposés dans le second conduit d'admission (194,200,204,202), lesdits seconds moyens formant soupape d'admission (210) étant déplaçables entre un état ouvert permettant la circulation dans le second conduit d'admission et un état fermé interrompant la circulation dans le second conduit d'admission, lesdits seconds moyens formant soupape d'admission (210) s'ouvrant en réponse à une différence de pression prédéterminée qui lui est appliquée, et se fermant en réponse à la suppression de ladite pression différentielle;
       lesdits premiers moyens formant soupape d'admission (190) étant normalement dans l'état ouvert pour permettre l'établissement d'une circulation d'admission de l'air ambiant dans le premier conduit d'admission (188) et une circulation des gaz d'échappement délivrés par la chambre de combustion du moteur dans le premier tuyau d'échappement (192), les moyens formant filtre (184;186) et le second tuyau d'échappement (206;208), et lesdits seconds moyens formant soupape d'admission (210) étant normalement dans l'état fermé;
       des moyens pour fermer de façon intermittente les premiers moyens formant soupape d'admission (190) pour rediriger le tirage d'admission dans le moteur, dans le second conduit d'admission (194,200,204,202), créer ladite diférence de pression prédéterminée et ouvrir lesdits seconds moyens formant soupape d'admission (210), de manière à produire une impulsion du courant d'admission traversant lesdits moyens formant filtre (184;186) et détacher ladite substance particulaire desdits moyens formant filtre et l'entraîner jusqu'à l'admission du moteur pour sa combustion dans ce dernier;
       des moyens pour ouvrir lesdits premiers moyens formant soupape d'admission (190) en réponse à la fermeture desdits seconds moyens formant soupape d'admission (210) lors de la suppression de ladite différence de pression.
EP86301517A 1985-03-05 1986-03-04 Procédé et appareil pour filtrer les particules solides à l'échappement d'un moteur Diesel Expired - Lifetime EP0194131B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT86301517T ATE79158T1 (de) 1985-03-05 1986-03-04 Verfahren und vorrichtung zum filtern von festen teilchen aus einem dieselmotorauspuff.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US70826085A 1985-03-05 1985-03-05
US708260 1985-03-05

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EP0194131A1 EP0194131A1 (fr) 1986-09-10
EP0194131B1 true EP0194131B1 (fr) 1992-08-05

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EP (1) EP0194131B1 (fr)
JP (1) JPS61268813A (fr)
KR (1) KR860007456A (fr)
AT (1) ATE79158T1 (fr)
AU (1) AU5430386A (fr)
BR (1) BR8600932A (fr)
CA (1) CA1287532C (fr)
DE (1) DE3686278T2 (fr)
ZA (1) ZA861609B (fr)

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CA1285493C (fr) * 1986-01-06 1991-07-02 Robert Hoch Methode et dispositif de captage des solides des echappements de moteurs diesel
JPH01159408A (ja) * 1987-09-25 1989-06-22 Asahi Glass Co Ltd ディーゼルエンジンの排気ガスの処理装置および処理方法
GB2218008A (en) * 1988-05-06 1989-11-08 Ford Motor Co Cleaning exhaust gas
JPH02185611A (ja) * 1989-01-10 1990-07-20 Asahi Glass Co Ltd 排気黒煙除去装置
US5457945A (en) * 1992-01-07 1995-10-17 Pall Corporation Regenerable diesel exhaust filter and heater
US5228891A (en) * 1992-01-07 1993-07-20 Pall Corporation Regenerable diesel exhaust filter
US5470364A (en) * 1992-01-07 1995-11-28 Pall Corporation Regenerable diesel exhaust filter
US5253476A (en) * 1992-02-21 1993-10-19 Northeastern University Pulsed, reverse-flow, regenerated diesel trap capturing soot, ash and PAH's
US5426936A (en) * 1992-02-21 1995-06-27 Northeastern University Diesel engine exhaust gas recirculation system for NOx control incorporating a compressed air regenerative particulate control system
CN1201071C (zh) * 2000-03-29 2005-05-11 丰田自动车株式会社 内燃机的废气净化装置
SE0002186L (sv) * 2000-06-09 2001-11-12 Volvo Lastvagnar Ab Arrangemang och metod för rengöring av partikelfilter med hjälp av en tongenerator
DE10312995B4 (de) * 2003-03-03 2011-12-15 J. Eberspächer GmbH & Co. KG Verfahren und Vorrichtung zum Reinigen eines Partikelfilters
EP1455059A1 (fr) * 2003-03-03 2004-09-08 J. Eberspächer GmbH & Co. Procédé et dispositif de nettoyage d'un filtre à particules
JP4954010B2 (ja) * 2007-10-01 2012-06-13 Ｕｄトラックス株式会社 エンジンの排気浄化装置
DE102009024535A1 (de) 2009-06-10 2010-12-16 J. Eberspächer GmbH & Co. KG Abgasnachbehandlungsvorrichtung
US8789360B2 (en) 2011-10-26 2014-07-29 Boshart Automotive Testing Services, Inc. Over temperature/pressure safety device for diesel particulate filters
JP5318180B2 (ja) * 2011-11-17 2013-10-16 Ｕｄトラックス株式会社 エンジンの排気浄化装置
KR102308530B1 (ko) * 2021-07-07 2021-10-06 주식회사 고산자 드론에 장착된 레이저를 이용한 지하시설물 측량시스템
CN117249507B (zh) * 2023-11-16 2024-03-19 广东汇绿实验室设备科技有限公司 一种实验室的无菌通风换气设备

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Also Published As

Publication number Publication date
EP0194131A1 (fr) 1986-09-10
JPS61268813A (ja) 1986-11-28
BR8600932A (pt) 1986-11-11
KR860007456A (ko) 1986-10-13
CA1287532C (fr) 1991-08-13
ZA861609B (en) 1986-10-29
DE3686278D1 (de) 1992-09-10
DE3686278T2 (de) 1993-03-18
AU5430386A (en) 1986-09-11
ATE79158T1 (de) 1992-08-15

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