WO2007109294A2 - Low temperature diesel particulate matter reduction system - Google Patents
Low temperature diesel particulate matter reduction system Download PDFInfo
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- WO2007109294A2 WO2007109294A2 PCT/US2007/006971 US2007006971W WO2007109294A2 WO 2007109294 A2 WO2007109294 A2 WO 2007109294A2 US 2007006971 W US2007006971 W US 2007006971W WO 2007109294 A2 WO2007109294 A2 WO 2007109294A2
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- WIPO (PCT)
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- filter
- flow
- substrate
- exhaust
- particulate
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
- B01D53/9404—Removing only nitrogen compounds
- B01D53/9409—Nitrogen oxides
- B01D53/9431—Processes characterised by a specific device
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
- B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
- B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
- B01D46/2418—Honeycomb filters
- B01D46/2451—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
- B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
- B01D46/2403—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies characterised by the physical shape or structure of the filtering element
- B01D46/2418—Honeycomb filters
- B01D46/2451—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure
- B01D46/2455—Honeycomb filters characterized by the geometrical structure, shape, pattern or configuration or parameters related to the geometry of the structure of the whole honeycomb or segments
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
- B01D46/52—Particle separators, e.g. dust precipitators, using filters embodying folded corrugated or wound sheet material
- B01D46/521—Particle separators, e.g. dust precipitators, using filters embodying folded corrugated or wound sheet material using folded, pleated material
- B01D46/525—Particle separators, e.g. dust precipitators, using filters embodying folded corrugated or wound sheet material using folded, pleated material which comprises flutes
- B01D46/527—Particle separators, e.g. dust precipitators, using filters embodying folded corrugated or wound sheet material using folded, pleated material which comprises flutes in wound arrangement
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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
- F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
- F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
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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
- F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
- F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
- F01N13/0093—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series the purifying devices are of the same type
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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
- F01N3/022—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
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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
- F01N3/022—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
- F01N3/0226—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 fibrous
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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
- F01N3/0231—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles using special exhaust apparatus upstream of the filter for producing nitrogen dioxide, e.g. for continuous filter regeneration systems [CRT]
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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
- F01N3/033—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 in combination with other devices
- F01N3/035—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 in combination with other devices with catalytic reactors, e.g. catalysed diesel particulate filters
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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
- F01N3/08—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
- F01N3/28—Construction of catalytic reactors
- F01N3/2803—Construction of catalytic reactors characterised by structure, by material or by manufacturing of catalyst support
- F01N3/2807—Metal other than sintered metal
- F01N3/281—Metallic honeycomb monoliths made of stacked or rolled sheets, foils or plates
- F01N3/2821—Metallic honeycomb monoliths made of stacked or rolled sheets, foils or plates the support being provided with means to enhance the mixing process inside the converter, e.g. sheets, plates or foils with protrusions or projections to create turbulence
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2267/00—Multiple filter elements specially adapted for separating dispersed particles from gases or vapours
- B01D2267/40—Different types of filters
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2279/00—Filters adapted for separating dispersed particles from gases or vapours specially modified for specific uses
- B01D2279/30—Filters adapted for separating dispersed particles from gases or vapours specially modified for specific uses for treatment of exhaust gases from IC Engines
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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
- F01N2330/00—Structure of catalyst support or particle filter
- F01N2330/02—Metallic plates or honeycombs, e.g. superposed or rolled-up corrugated or otherwise deformed sheet metal
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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
- F01N2330/00—Structure of catalyst support or particle filter
- F01N2330/06—Ceramic, e.g. monoliths
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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
- F01N2330/00—Structure of catalyst support or particle filter
- F01N2330/10—Fibrous material, e.g. mineral or metallic wool
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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
- F01N2330/00—Structure of catalyst support or particle filter
- F01N2330/30—Honeycomb supports characterised by their structural details
- F01N2330/38—Honeycomb supports characterised by their structural details flow channels with means to enhance flow mixing,(e.g. protrusions or projections)
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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
- F01N2330/00—Structure of catalyst support or particle filter
- F01N2330/30—Honeycomb supports characterised by their structural details
- F01N2330/44—Honeycomb supports characterised by their structural details made of stacks of sheets, plates or foils that are folded in S-form
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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
- F01N2330/00—Structure of catalyst support or particle filter
- F01N2330/60—Discontinuous, uneven properties of filter material, e.g. different material thickness along the longitudinal direction; Higher filter capacity upstream than downstream in same housing
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- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2430/00—Influencing exhaust purification, e.g. starting of catalytic reaction, filter regeneration, or the like, by controlling engine operating characteristics
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- 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
- F01N2510/00—Surface coverings
- F01N2510/06—Surface coverings for exhaust purification, e.g. catalytic reaction
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- 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
- F01N2510/00—Surface coverings
- F01N2510/06—Surface coverings for exhaust purification, e.g. catalytic reaction
- F01N2510/068—Surface coverings for exhaust purification, e.g. catalytic reaction characterised by the distribution of the catalytic coatings
- F01N2510/0682—Surface coverings for exhaust purification, e.g. catalytic reaction characterised by the distribution of the catalytic coatings having a discontinuous, uneven or partially overlapping coating of catalytic material, e.g. higher amount of material upstream than downstream or vice versa
Definitions
- the present disclosure relates generally to diesel engine exhaust systems. More particularly, the present disclosure relates to systems and methods for controlling diesel engine exhaust emissions.
- Diesel engine exhaust contains particulate matter, the emission of which is regulated for environmental and health reasons.
- This particulate matter generally constitutes a soluble organic fraction ("SOF") and a remaining portion of hard carbon.
- SOF soluble organic fraction
- the soluble organic fraction may be partially or wholly removed through oxidation in an oxidation catalyst device such as a catalytic converter; however, this typically results in a reduction of only about 20 percent of total particulate emissions.
- vehicles equipped with diesel engines may include diesel particulate filters for more completely removing the particulate matter from the exhaust stream, including the hard carbon portion.
- Conventional wall flow type diesel particulate filters may have particulate removal efficiencies of about 85 percent.
- diesel particulate filters particularly those that have relatively high particulate filtration efficiency, are generally associated with high back pressures because of the restriction to flow through the filter. Further, with use, soot or other carbon-based particulate matter accumulates on the diesel particulate filters causing the buildup of additional undesirable back pressure in the exhaust systems. Engines that have large particulate mass emission rates may develop excessive back pressure levels in a relatively short period of time. High back pressures decrease engine efficiency and reduce engine performance. Therefore, it is desired to have diesel particulate filtration systems that minimize back pressure while capturing a high percentage of the particulate matter in the exhaust.
- DPFs Conventional wall flow diesel particulate filters
- a porous-walled honeycomb substrate i.e., monolith
- channels that extend generally from an upstream end to a downstream end of the substrate.
- This plugged configuration forces exhaust flow to pass radially through the porous walls defining the channels of the substrate in order to exit the diesel particulate filter.
- particulate matter may be oxidized by burning off (i.e., oxidizing) the particulates that accumulate on the filters. It is known to those of skill in the art that one method by which particulate matter may be oxidized is to raise the temperature of the exhaust gas sufficiently to allow the excess oxygen in the exhaust gas to oxidize the particulate matter. Also well- known to those of skill in the art is that particulate matter may be oxidized at a lower temperature in the presence of sufficient amounts of nitrogen dioxide (NO 2 )-
- Diesel exhaust inherently contains nitrogen oxides (NO x ), which consist primarily of nitric oxide (NO) and nitrogen dioxide (NO2).
- NO x nitrogen oxides
- NO 2 inherently present in the exhaust stream is a relatively small percentage of total NO x , such as in the range of 5 to 20 percent but usually in the range of 5 to 10 percent.
- NO 2 inherently present in the exhaust stream is a relatively small percentage of total NO x , such as in the range of 5 to 20 percent but usually in the range of 5 to 10 percent.
- NO 2 inherently present in the exhaust stream is a relatively small percentage of total NO x , such as in the range of 5 to 20 percent but usually in the range of 5 to 10 percent.
- the effectiveness of NO 2 in regenerating a particulate filter depends in part on the ratio OfNO x to particulate matter in the exhaust stream.
- One method to produce sufficient quantities OfNO 2 is to use an oxidation catalyst to oxidize a portion of the NO present in the exhaust stream to NO2.
- a catalytic converter including a diesel oxidation catalyst can be positioned upstream from the diesel particulate filter and/or the diesel particulate filter itself can include a diesel oxidation catalyst.
- these types of prior art arrangements may result in excessive NO2 emissions.
- One aspect of the present disclosure relates to a system for reducing particulate material emissions in diesel engine exhaust.
- the system is adapted to optimize the use OfNO 2 to remove particulate matter (PM) from the exhaust stream and to passively regenerate a diesel particulate filter that is a part of the system.
- PM particulate matter
- Another aspect of the present disclosure relates to a diesel particulate filtration system that at least one upstream filter to optimize the NO 2 to PM ratio at a downstream filter.
- the upstream filter is a catalyzed flow- through filter
- the downstream filter is a catalyzed wall flow filter.
- inventive aspects relate to individual features as well as combinations of features. It is to be understood that both the forgoing general description and the following detailed description merely provide examples of how the inventive aspects may be put into practice, and are not intended to limit the broad spirit and scope of the inventive aspects.
- Figure 1 schematically illustrates an exhaust system having features that are examples of inventive aspects in accordance with the principles of the present disclosure.
- Figure 2 illustrates an example flow-through filter that can be used as an upstream filter in the system of Figure 1 ;
- Figure 3 illustrates an enlarged, exploded view of a portion of the filter of
- Figure 4 illustrates a further enlarged, exploded view of a portion of the filter of Figure 2
- Figure 5 is a schematic representation showing the operation of the filter of Figure 2;
- Figure 6 is a cut-away view of an example wall flow filter that can be used as the downstream filter in the system of Figure 1;
- Figure 6A illustrates the wall flow filter of Figure 6 coated with a catalyst using a zone-coating technique;
- Figure 7 is an enlarged portion of Figure 6;
- Figure 8 is a graph showing a FTP transient cycle
- Figure 9 is a temperature profile graph for a diesel engine for different torque cycling
- Figure 10 is a graph that plots NO 2 generation for 3 test systems.
- Figure 11 is a graph that plots particulate accumulation on the downstream filter of the 3 test systems.
- One way to increase the NO 2 ZPM ratio at a filter is to decrease the PM on the filter rather than increase the concentration of NO2 at the filter.
- a combination of an upstream filter and a downstream filter can be used.
- the upstream filter can have a lower filtration efficiency than the filtration efficiency of the downstream filter.
- the upstream filter includes a flow- through filter (FTF), and the downstream filter includes a wall flow filter.
- FFF flow- through filter
- the system preferably optimizes the NO 2 ZPM ratio on both filters such that an optimum amount OfNO 2 is generated.
- the system allows for the effective passive regeneration of the downstream filters at relatively low temperatures thereby preventing plugging of the downstream filter, and also minimizes the concentration OfNO 2 that exits the tailpipe.
- Flow-through filters partially intercept solid PM particles in exhaust. Some flow-through filters may exhibit a filtration efficiency of 50% or less.
- the downstream filter may be a wall-flow filter.
- the wall-flow filter may have a filtration efficiency of at least 75% or higher. Both filters may be catalyzed to remove and oxidize HC, CO, and PM. Because of the flow-through nature, a portion of PM is intercepted in the first filter and the rest of the PM passes to the downstream high efficiency filter.
- the catalyst on the FTF may be chosen to just oxidize a selected portion of NO coming from engine exhaust to NO 2 . Then, a portion of the NO 2 can be used to oxidize captured PM, transferring the used NO 2 back to NO, which can be reused by catalyst inside the filter downstream before being released.
- the second filter may be catalyzed in such a way that the NO 2 being left over from the first filter and NO2 being generated at the front section may be consumed by the captured soot at the middle and rear section of the second filter.
- the configuration of the system including the design of the first filter to achieve a desired filtration efficiency and oxidation ability, allows the tailpipe NO 2 / NO x ratio to be reduced to levels to meet California Air Resource Board Regulation.
- Prior art systems have used a straight channel catalytic converter positioned upstream from a wall flow filter to increase the concentration OfNO 2 at the wall flow filter.
- the present disclosure teaches using a flow-through filter upstream of the wall flow filter instead of a straight channel catalytic converter.
- Flow-through filters provide a number of advantages over catalytic converters. For example, flow-through filters provide higher residence times to allow locally generated NO 2 to react with a larger portion of PM (including both soluble organic fractions and hard carbon constituents) coming from engine. This decreases the PM portion that enters the down stream filter and increases NO 2 /PM ratio inside the downstream filter. By optimizing the NO 2 /PM ratio, the downstream filter is boosted to work efficiently at lower temperatures.
- catalytic converter systems typically use a heavily catalyzed catalytic converter upstream of a catalyzed DPF.
- a catalytic converter can consume soluble fraction of particulate matters, but does not affect the concentration of hard carbon soot in the exhaust.
- multistage filtration with a catalyzed flow through pre-filter followed by a catalyzed DPF is a better solution with maximized soot-NO2 residence time and minimized NO2 emissions at the tailpipe.
- the combination of the FTF and the DPF may lead to a filtration efficiency of higher than 92% and NO 2 / NO x ratio on a CAT 3126 engine over FTP cycle to 28% which may exhibit a 20% increase of NO 2 / NO x percentage across the device from the engine out NO 2 / NO x level.
- a device may improve PM filtration efficiency and reduce the system-out NO 2 to meet CARB NO 2 rule.
- the primary PM reduction from the FTF can increase the N0 x /PM ratio inside the downstream DPF, hence the captured soot oxidized at a relatively lower temperature, leading to lower application criteria.
- FIG. 1 illustrates an exhaust system 20 that is in accordance with inventive aspects of the present disclosure.
- the system includes an engine 22 (e.g., a diesel engine) and an exhaust conduit 24 for conveying exhaust gas away from the engine 22.
- a first diesel particulate reduction device 26 is positioned in the exhaust stream. Downstream from the first diesel particulate reduction device 26 is a second diesel particulate reduction device 28. It will be appreciated that the first diesel particulate reduction device 26 and the second diesel particulate reduction device 28 function together to treat the exhaust gas that passes through the conduit 24. It will also be appreciated that the first diesel particulate reduction device 26 and the second diesel particulate reduction device 28 may be separated by any distance, including being positioned in close proximity or even in direct contact.
- the first diesel particulate device 26 is preferably a flow-through filter.
- Flow-through filters are filters that typically have moderate particulate mass reduction efficiencies.
- particulate mass reduction efficiency is determined by subtracting the particulate mass that enters the filter from the particulate mass that exits the filter, and by dividing the difference by the particulate mass that enters the filter.
- the test duration and engine cycling during testing are preferably determined by the Federal Test Procedure (FTP) heavy-duty transient cycle that is currently used for emission testing of heavy-duty on-road engines in the United States (see CFR Title 40, Part 86.1333).
- a typical flow-through filter has a particulate mass reduction efficiency of 50 percent or less.
- Certain flow-through filters do not require all of the exhaust gas traveling through the filter to pass through a filter media having a pore size sufficiently small to trap particulate material.
- a flow-through filter includes a plurality of flow-through channels that extend longitudinally from the entrance end to the exit end of the flow-through filter.
- the flow-through filter also includes filter media that is positioned between at least some of the flow-through channels.
- the filter further includes flow diversion structures that generate turbulence in the flow-through channels.
- the flow diversion structures also function to divert at least some exhaust flow from one flow-through channel to another flow-through channel. As the exhaust flow is diverted from one flow- through channel to another, the diverted flow passes through the filter media causing some particulate material to be trapped within the filter media.
- This flow- through-type filter yields moderate filtration efficiencies, typically up to 50% per filter, with relatively low back pressure.
- a catalyst coating (e.g., a precious metal coating) can be provided on the flow-through channels of the flow-through filter to promote the oxidation of the soluble organic fraction (SOF) of the particulate matter to gaseous components and to promote the oxidation of a portion of the nitric oxide (NO) within the exhaust gas to nitrogen dioxide (NO 2 ). Furthermore, the filter media of the flow-through filter captures a portion of the hard carbon particulate matter and a portion of the non-oxidized SOF present in the exhaust.
- SOF soluble organic fraction
- NO nitric oxide
- the filter media can also be coated with a catalyst (e.g., a precious metal such as platinum).
- the first diesel particulate reduction device 26 can also be referred to as an upstream diesel particulate reduction device 26.
- An example upstream diesel particulate reduction device 26 is shown at Figures 2-5.
- the device 26 includes a canister 27 housing a substrate (e.g., a honeycomb body) constructed from multiple layers of filtration material 30 sandwiched between layers of corrugated metallic foil 32.
- the corrugated metallic foil 32 defines elongated passageways 34 (i.e., channels) that are generally parallel to a net flow direction 7 of exhaust gases through the particulate reduction device.
- the metallic foil 32 preferably includes structures that generate turbulence for ensuring that mixing occurs within the substrate.
- the structures include openings 33 and flow diverting surfaces 35 (i.e., mixing surfaces, deflecting surfaces, mixing shovels, flow diversion structures or like terms).
- the flow diverting surfaces 35 cause some flow to be diverted within the passageways 34 from the net flow direction 7 to transverse directions 9 and radial directions 11. At least some of the diverted flow travels through the openings 33 between adjacent passageways 34 and through the filtration material 30. As the exhaust flow travels through the filtration material 30, at least some particulate material of the exhaust stream is captured by the filtration material 30. As shown at Figure 5, the diverting surfaces 35 do not completely block/plug the passageways 34. This assists in keeping the pressure drop across the device 26 relatively low.
- the filtration material 30 is a woven-type material constructed from metallic fibers (e.g., a metallic fabric or fleece) which capture particles both by impingement and by blocking their flow.
- the particle-blocking properties of the filtration material 30 are determined in part by the diameter of the metallic fibers used to construct the fleece. For example, metallic fibers of 20 to 28 microns (millionths of a meter) and 35 to 45 microns have been found to work acceptably. As the exhaust gases flow out of the foil 32 and into the filtration material 30, significant internal turbulence is induced.
- types of filtration material other than metallic fleece could also be used
- the device 26 has a diameter of about 10.5 inches and a length of about 3 inches, with 200 cpsi.
- the residence time of the device 26 can be at least 10% or 15% greater than the residence time of a standard straight channel flow-through catalytic converter having the same space velocity.
- the space velocity (i.e., the volumetric flow rate of the exhaust gas divided by the volume of the particulate reduction device) of the upstream particulate removal device 26 is greater than the space velocity of the downstream particulate removal device 28.
- the space velocity of the upstream particulate reduction device is equal to at least 2, 3 or 4 times the space velocity of the downstream particulate reduction device for a given volumetric flow rate.
- the space velocity of the upstream particulate reduction device is equal to 2-6 or 3-5 times the space velocity of the downstream particulate reduction device for a given volumetric flow rate.
- the device 26 can have a particulate mass reduction efficiency of 15-50 percent or 20- 50 percent.
- the first diesel particulate reduction device 26 is manufactured by Emitec Gmbh and sold under the name "PM Kat.”
- the device 26 may, however, comprise any flow-through-type construction known to those of skill in the art, such as wire mesh, metallic or ceramic foam. Further details relating to the constructions of the Emitec filters suitable for use as upstream filters can be found at U.S. Patent Application Publication Numbers US 2005/0232830, US 2005/0274012 and US 2005/0229590, which are hereby incorporated by reference in their entireties.
- the upstream diesel particulate reduction device 26 also contains a catalyst coating adapted to promote the oxidation of hydrocarbons and the conversion of NO to NO 2 .
- catalyst coatings include precious metals such as platinum, palladium and rhodium, and other types of components such as alumina, cerium oxide, base metal oxides (e.g., lanthanum, vanadium, etc,) or zeolites.
- a preferred catalyst for the first particulate reduction device 26 is platinum with a loading level greater than 50 grams/cubic foot of substrate. In other embodiments the platinum loading level is in the range of 50-100 grams/cubic foot of substrate. In a preferred embodiment, the platinum loading is about 70 grams/cubic foot.
- the catalyst coating is available from Intercat, Inc.
- the device 26 may exhibit a 27% PM reduction efficiency.
- the NO 2 / NO x ratio at the out end of the device 26 on a CAT 3126 engine over FTP cycle is around 32%.
- the second diesel particulate reduction device 28, also called the downstream diesel particulate reduction device 28, can have a variety of known configurations.
- the device 28 is depicted as a wall-flow filter having a substrate 50 housed within an outer casing 52.
- the substrate 50 can have a ceramic (e.g., a foamed ceramic) monolith construction.
- a mat layer 54 can be mounted between the substrate 50 and the casing 52. Ends 56 of the casing can be bent radially inwardly to assist in retaining the substrate 50 within the casing 52. End gaskets 58 can be used to seal the ends of the device 28 to prevent flow from passing through the mat to by-pass the substrate 50.
- the device 28 has a diameter of about 10.5 inches and a length of about 12 inches, with 200 cpsi/12 mil.
- the substrate 50 includes walls 60 defining a honeycomb arrangement of longitudinal passages 62 (i.e., channels) that extend from a downstream end 63 to an upstream end 64 of the substrate 50.
- the passages 62 are selectively plugged adjacent the upstream and downstream ends 63, 64 such that exhaust flow is forced to flow radially through the walls 60 between the passages 62 in order to pass through the device 28. As shown at Figure 7, this radial wall flow is represented by arrows 66.
- An example diesel particulate reduction device is a wall-flow filter having a monolith ceramic substrate including a "honey-comb" configuration of plugged passages as described in United States Patent No. 4,851,015 that is hereby incorporated by reference in its entirety.
- Example materials for manufacturing the substrate 50 include cordierite, mullite, alumina, SiC, refractory metal oxides, or other materials conventionally used as catalyzed substrates.
- the device 28 includes a diesel particulate filter sold by Engelhard Corporation under the name "DPX Filter.”
- the substrate 50 can be coated a catalyst.
- catalysts include precious metals such as platinum, palladium and rhodium, and other types of components such as base metal oxides or rare earth metal oxides.
- the substrate 50 has a platinum loading of 30-80 grams per cubic foot. In a preferred embodiment, the substrate 50 has a platinum loading of about 50 grams per cubic foot, m another embodiment of the diesel particulate reduction device 28, the substrate 50 may have a precious metal loading of about 25 grams per cubic foot, wherein the filter is coated substantially uniformly throughout its length. In one embodiment of the diesel particulate device 28, the substrate 50 may have a precious metal loading between about 5 and 35 grams per cubic foot, wherein the filter is coated substantially uniformly throughout its length.
- the upstream particulate reduction device 26 preferably has a higher precious metal loading than the downstream particulate reduction device 28.
- the precious metal loading of the upstream device 26 is at least 10 percent, 20 percent, 30 percent or 40 percent higher than the precious metal loading of the downstream device 28.
- the precious metal loading of the upstream device 26 is in the range of 10-80 percent, 20-60 percent or 30-50 percent higher than the precious metal loading of the downstream device 28.
- catalyst coating of the substrate 50 may be banded with first 2 inches being coated at 48g/ft3 and the last 10 inches being coated at 2g/ft3 for a filter having a length of 12 inches.
- the downstream particulate reduction device exhibited a filtration efficiency higher than 85%.
- the NCV NO x ratio out of the filter on a CAT 3126 engine over FTP cycle was essentially the same as the ratio out of the engine at 8%.
- the downstream device 28 may be zone-coated with a catalyst, wherein the substrate 50 is coated at the ends with a wash coat including a catalyst and is not coated with a wash coat at the middle of the substrate 50.
- first and third zones 71, 73, respectively are located at the ends of the substrate 50 and are coated with a wash coat.
- a second, middle zone 72 is positioned between the first and the third zones 71, 73, respectively, and is not coated with a wash coat.
- the sizes of the wash coated zones may vary in different embodiments of the filter.
- the first coated zone 71 of the filter 28 may be between about 1/6 and 1/3 of the length of the filter 28 and the third coated zone 73 may be between about 1/6 and 1/3 of the length of the filter 28.
- the precious metal loading values may also vary in different embodiments of the filter.
- the precious metal loading of the first zone 71 may be between about 25 and 50 grams/cubic foot and the precious metal loading of the third zone 73 may be between about 5 and 50 grams/cubic foot.
- the overall precious metal loading of the filter 28 may be between about 5 and 35 grams/cubic foot.
- the first and the last 3 inches of the device 28 may be wash-coated with a catalyst at a precious metal loading of about 50 grams/cubic foot and the middle 6 inches may be left uncoated.
- the overall precious metal loading of the filter 28 would be around 25 grams/cubic foot.
- the filter 28 may be zone-coated, but with different levels of loading on the coated portions. For example, for a filter that is 12 inches in length and 10.5 inches in diameter, the first (inlet) 3 inches may be wash coated with 50 grams/cubic foot of precious metal loading and the last (outlet) 3 inches may be coated with 10 grams/cubic foot of precious metal loading and the middle 6 inches may be left uncoated. In such an embodiment, the overall precious metal loading of the filter 28 would be around 15 grams/cubic foot.
- the diesel particulate reduction device 28 preferably has a particulate mass reduction efficiency greater than 75%. More preferably, the diesel particulate reduction device 28 has a particulate mass reduction efficiency greater than 85%. Most preferably, the diesel particulate reduction device 28 has a particulate mass reduction efficiency equal to or greater than 90%. It is preferred for the particulate reduction device 28 to have a higher particulate mass reduction efficiency than the particulate reduction device 26. In certain embodiments, the particulate mass reduction efficiency of the device 28 is at least 50, 100, 200, 300, 400 or 500 percent higher than the particulate mass reduction efficiency of the device 26. In other embodiments, the particulate mass reduction efficiency of the device 28 is at least 50-600 or 100-500 or 200-500 percent higher than the particulate mass reduction efficiency of the device 26.
- the ratio of the mass of NO 2 to the mass of particulate matter in the exhaust stream between the upstream device 26 and the downstream device 28 is preferably between 8 and 14. More preferably, this ratio is between 8 and 12.
- the concentration of NO 2 between the devices 26, 28 it is desirable for the concentration of NO 2 between the devices 26, 28 to be in the range of 50-700 parts per million. In other embodiments, the ratio of NO 2 to total NO x between the devices 26, 28 is in the range of 20-55 percent or in the range of 30-50 percent.
- the ratio of NO 2 to NO x can be determined by measuring the total amount of NO2 and the total amount OfNO x in the exhaust stream between the upstream and downstream filters, and the dividing the total NO 2 by the total NO x to obtain a flow weighted average over a given test period.
- An example test period and engine cycling protocol during testing are set for by the FTP heavy-duty transient cycle that is currently used for emission testing of heavy-duty on-road engines in the United States.
- a first portion of the particulate matter contained in the diesel exhaust is deposited on the first diesel particulate reduction device 26 in an amount that is a function of the particle capture efficiency of the first diesel particulate reduction device 26.
- the exhaust gas exits the first diesel particulate reduction device 26 containing a residual portion of particulate matter, defined as the amount of particulate matter not deposited on the first diesel particulate reduction device 26.
- the exhaust gas thereafter enters the second diesel particulate reduction device 28, where a portion of the particulate matter present in the exhaust gas is deposited on the second diesel particulate reduction device 28 according to the particle capture efficiency of the second diesel particulate reduction device 28.
- the SOF portion of particulate matter is oxidized by contact with the oxidation catalyst coating. Furthermore, the NO present within the exhaust stream is converted to NO2 by the oxidation catalyst coating within the first diesel particulate reduction device 26. A portion of this NO 2 , along with the NO2 inherently present in the exhaust gas, reacts with the particulate matter trapped on the first diesel particulate reduction device 26.
- the exhaust gas exiting the first diesel particulate reduction device 26 contains a residual portion of NO 2 .
- This exhaust gas then enters the second diesel particulate reduction device 28 and the NO2 in the exhaust stream reacts with soot on the device 28, converting a portion of the NO 2 into NO and regenerating the device 28.
- soot on the device 28 reacts with soot on the device 28, converting a portion of the NO 2 into NO and regenerating the device 28.
- particulate matter is captured and the particulate reduction devices are regenerated while minimizing NO 2 emissions.
- the preferred design of the particulate reduction devices create significant internal, three-dimensional, turbulent flow patterns by virtue of the highly tortuous, twisted flow vectors that result from flow impacting into the filtration material 30 and being channeled into and out of the openings in the corrugated foil 32.
- System A is an example of system in accordance with the principles of the present disclosure.
- System A included an Emitec PM Kat flow-through filter positioned upstream from a wall flow filter.
- the Emitec filter had a platinum loading of about 70 grams per cubic foot while the wall flow filter had a platinum loading of about 50 grams per cubic foot.
- the Emitec filter had a diameter of 10 1/2 inches and a length of about 3 inches, and the wall flow filter had a diameter of 10 1/2 inches and a length of about 12 inches.
- the Emitec filter had a particulate mass reduction efficiency less than 50 percent, while the wall flow filter had a particulate mass reduction efficiency greater than 85 percent.
- System B was manufactured by Johnson Matthey, Inc. and sold under the name CCRT.
- the system included a catalytic converter positioned upstream from a catalyzed wall/flow filter.
- System C had the same configuration as System A, except the Emitec filter was loaded with a low NO 2 producing catalyst sold by Engelhard.
- the catalyst includes constituents that inhibit the production of NO 2 , but allow the oxidation of hydrocarbons.
- the platinum loading for the low NO2 producing catalyst was also 70 grams per cubic foot.
- FIG. 8 shows the FTP transient cycle as a plot of the engine torque and speed over a 20 minute time period. The cycle is divided into 4 phases including the New York Non Freeway (NYNF) phase, the Los Angeles Non Freeway (LANF) phase, the Los Angeles Freeway (LAF) phase and the New York Non Freeway (NYNF) phase.
- NYNF New York Non Freeway
- LEF Los Angeles Non Freeway
- NYNF New York Non Freeway
- Figure 9 shows temperature profiles for exhaust generated from the caterpillar 3126 diesel engine during FTP transient cycling.
- the cycling was done at different torque levels.
- the 100 percent line represents testing done at torque level that match the standard FTP transient cycle shown at Figure 8.
- the other profiles were generated by using the same transient cycling, but with the torques lowered a certain percentage relative to the standard torque levels during the federal transient testing protocol.
- the 85 percent line represents a torque level of 85 percent of the standard torque level specified by the standard FTP transient cycle shown at Figure 8. Similar plot lines are provided for 77%, 70%, 55%, 48% and 40% of the torque levels set by the standard FTP transient cycle.
- the exhaust temperature is above 220 0 C for about 37% of the testing duration.
- Figure 10 shows the percentage of NO 2 relative to total NO x between the afteitreatment devices for each of the systems. The NO 2 to NO x percentage is shown across the range of torque levels at which the federal transient testing protocol was conducted.
- the graph of Figure 10 shows that System A generated moderate levels OfNO 2 (e.g., generally less than 50%), System B generated relatively high levels of NO 2 (e.g., generally greater than 60%) and System C generated relatively low levels of NO 2 (e.g., generally less than
- Figure 11 is a graph showing the weight gain on the downstream filters of each of the systems when subjected to federal transient testing protocol cycles at torque levels of 48% for an extended duration.
- a CAT 3126 diesel engine having a 210 horsepower at 2200 RPM was used.
- particulate material was emitted from the engine at an average rate of 3.67 grams per hour.
- System A experienced relatively low weight gain during the testing period.
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Abstract
A system for treating diesel exhaust is disclosed. The system includes a first filter (26) including layers of filtration material (30) positioned between layers of corrugated metallic foil (32). The metallic foil defines a honeycomb arrangement of longitudinal passageways (34) from an upstream end to a downstream end and also openings (33) for allowing exhaust to pass between adjacent longitudinal passageways of the metallic foil. The filtration material is positioned such that exhaust between the adjacent longitudinal passageways passes through the filtration material. The metallic foil also includes flow diverting structures (25) to divert flow within the longitudinal passageways through the openings. A second filter (28) is positioned downstream from the first filter. The second filter defines a honeycomb arrangement of longitudinal passageways (62). The longitudinal passages are selectively plugged adjacent upstream and downstream ends (63, 64) to force flow radially through walls between the longitudinal passages of the second filter.
Description
LOW TEMPERATURE DIESEL PARTICULATE MATTER REDUCTION
SYSTEM
This application is being filed on 20 March 2007 as a PCT International Patent application in the name of Donaldson Company, Inc., a U.S. national corporation, applicant for the designation of all countries except the US, and Wenzhong Zhang, a citizen of China, and Todd R. Taubert, Timothy L. Ricke, and Julian A. Imes, all citizens of the U.S., applicants for the designation of the US only, and claims the priority to U.S. Provisional Patent Application Serial No. 60/784,621, filed March 21, 2006, which application is hereby incorporated by reference in its entirety.
Technical Field
The present disclosure relates generally to diesel engine exhaust systems. More particularly, the present disclosure relates to systems and methods for controlling diesel engine exhaust emissions.
Background
Diesel engine exhaust contains particulate matter, the emission of which is regulated for environmental and health reasons. This particulate matter generally constitutes a soluble organic fraction ("SOF") and a remaining portion of hard carbon. The soluble organic fraction may be partially or wholly removed through oxidation in an oxidation catalyst device such as a catalytic converter; however, this typically results in a reduction of only about 20 percent of total particulate emissions. Thus, vehicles equipped with diesel engines may include diesel particulate filters for more completely removing the particulate matter from the exhaust stream, including the hard carbon portion. Conventional wall flow type diesel particulate filters may have particulate removal efficiencies of about 85 percent. However, diesel particulate filters, particularly those that have relatively high particulate filtration efficiency, are generally associated with high back pressures because of the restriction to flow through the filter. Further, with use, soot or other carbon-based particulate matter accumulates on the diesel particulate filters causing the buildup of additional undesirable back pressure in the exhaust
systems. Engines that have large particulate mass emission rates may develop excessive back pressure levels in a relatively short period of time. High back pressures decrease engine efficiency and reduce engine performance. Therefore, it is desired to have diesel particulate filtration systems that minimize back pressure while capturing a high percentage of the particulate matter in the exhaust.
Conventional wall flow diesel particulate filters (DPFs) are high particulate removal efficiency filters that include a porous-walled honeycomb substrate (i.e., monolith) with channels that extend generally from an upstream end to a downstream end of the substrate. Generally half the channels are plugged adjacent the downstream end of the substrate and the other half of the channels are plugged adjacent the upstream end of the substrate. This plugged configuration forces exhaust flow to pass radially through the porous walls defining the channels of the substrate in order to exit the diesel particulate filter.
To prevent diesel particulate filters from becoming excessively loaded with particulate matter, it is necessary to regenerate the diesel particulate filters by burning off (i.e., oxidizing) the particulates that accumulate on the filters. It is known to those of skill in the art that one method by which particulate matter may be oxidized is to raise the temperature of the exhaust gas sufficiently to allow the excess oxygen in the exhaust gas to oxidize the particulate matter. Also well- known to those of skill in the art is that particulate matter may be oxidized at a lower temperature in the presence of sufficient amounts of nitrogen dioxide (NO2)-
Diesel exhaust inherently contains nitrogen oxides (NOx), which consist primarily of nitric oxide (NO) and nitrogen dioxide (NO2). Typically, the NO2 inherently present in the exhaust stream is a relatively small percentage of total NOx, such as in the range of 5 to 20 percent but usually in the range of 5 to 10 percent. Although some regeneration of a diesel particulate filter occurs at such levels, it is insufficient to result in complete regeneration. The effectiveness of NO2 in regenerating a particulate filter depends in part on the ratio OfNOx to particulate matter in the exhaust stream. Generally, the reaction of "2NO2 + C = CO2 + 2NO" requires 8 times NO2 per unit of C in mass.
To promote full regeneration, it is often necessary to increase the quantity OfNO2 in the exhaust stream. This is particularly true where the NOx/particulate ratio is relatively small. One method to produce sufficient quantities OfNO2 is to
use an oxidation catalyst to oxidize a portion of the NO present in the exhaust stream to NO2. For example, a catalytic converter including a diesel oxidation catalyst can be positioned upstream from the diesel particulate filter and/or the diesel particulate filter itself can include a diesel oxidation catalyst. However, these types of prior art arrangements may result in excessive NO2 emissions.
Summary
One aspect of the present disclosure relates to a system for reducing particulate material emissions in diesel engine exhaust. In one embodiment, the system is adapted to optimize the use OfNO2 to remove particulate matter (PM) from the exhaust stream and to passively regenerate a diesel particulate filter that is a part of the system.
Another aspect of the present disclosure relates to a diesel particulate filtration system that at least one upstream filter to optimize the NO2 to PM ratio at a downstream filter. In one embodiment, the upstream filter is a catalyzed flow- through filter, and the downstream filter is a catalyzed wall flow filter.
Examples representative of a variety of inventive aspects are set forth in the description that follows. The inventive aspects relate to individual features as well as combinations of features. It is to be understood that both the forgoing general description and the following detailed description merely provide examples of how the inventive aspects may be put into practice, and are not intended to limit the broad spirit and scope of the inventive aspects.
Brief Description of the Drawings Figure 1 schematically illustrates an exhaust system having features that are examples of inventive aspects in accordance with the principles of the present disclosure.
Figure 2 illustrates an example flow-through filter that can be used as an upstream filter in the system of Figure 1 ;. Figure 3 illustrates an enlarged, exploded view of a portion of the filter of
Figure 2;
Figure 4 illustrates a further enlarged, exploded view of a portion of the filter of Figure 2;
Figure 5 is a schematic representation showing the operation of the filter of Figure 2;
Figure 6 is a cut-away view of an example wall flow filter that can be used as the downstream filter in the system of Figure 1; Figure 6A illustrates the wall flow filter of Figure 6 coated with a catalyst using a zone-coating technique;
Figure 7 is an enlarged portion of Figure 6;
Figure 8 is a graph showing a FTP transient cycle;
Figure 9 is a temperature profile graph for a diesel engine for different torque cycling;
Figure 10 is a graph that plots NO2 generation for 3 test systems; and
Figure 11 is a graph that plots particulate accumulation on the downstream filter of the 3 test systems.
Detailed Description
At relatively low temperatures (e.g., 200 to 3500C), NO2 molecules are typically more active for combusting soot than O2. NO2 reacts with soot according to the following reaction: 2NO2 + C = CO2 + 2NO. This reaction requires 8 times more NO2 per unit of C in mass. The NO2ZPM ratio is a significant factor to boost this reaction.
One way to increase the NO2ZPM ratio at a filter is to decrease the PM on the filter rather than increase the concentration of NO2 at the filter. To achieve this goal, a combination of an upstream filter and a downstream filter can be used. The upstream filter can have a lower filtration efficiency than the filtration efficiency of the downstream filter. In one embodiment, the upstream filter includes a flow- through filter (FTF), and the downstream filter includes a wall flow filter. The system preferably optimizes the NO2ZPM ratio on both filters such that an optimum amount OfNO2 is generated. Preferably, the system allows for the effective passive regeneration of the downstream filters at relatively low temperatures thereby preventing plugging of the downstream filter, and also minimizes the concentration OfNO2 that exits the tailpipe.
Flow-through filters partially intercept solid PM particles in exhaust. Some flow-through filters may exhibit a filtration efficiency of 50% or less. As
discussed above, in accordance with the disclosure, while the first staged filter may be an FTF, the downstream filter may be a wall-flow filter. The wall-flow filter may have a filtration efficiency of at least 75% or higher. Both filters may be catalyzed to remove and oxidize HC, CO, and PM. Because of the flow-through nature, a portion of PM is intercepted in the first filter and the rest of the PM passes to the downstream high efficiency filter. The catalyst on the FTF may be chosen to just oxidize a selected portion of NO coming from engine exhaust to NO2. Then, a portion of the NO2 can be used to oxidize captured PM, transferring the used NO2 back to NO, which can be reused by catalyst inside the filter downstream before being released.
The second filter may be catalyzed in such a way that the NO2 being left over from the first filter and NO2 being generated at the front section may be consumed by the captured soot at the middle and rear section of the second filter. The configuration of the system, including the design of the first filter to achieve a desired filtration efficiency and oxidation ability, allows the tailpipe NO2/ NOx ratio to be reduced to levels to meet California Air Resource Board Regulation.
Prior art systems have used a straight channel catalytic converter positioned upstream from a wall flow filter to increase the concentration OfNO2 at the wall flow filter. The present disclosure teaches using a flow-through filter upstream of the wall flow filter instead of a straight channel catalytic converter. Flow-through filters provide a number of advantages over catalytic converters. For example, flow-through filters provide higher residence times to allow locally generated NO2 to react with a larger portion of PM (including both soluble organic fractions and hard carbon constituents) coming from engine. This decreases the PM portion that enters the down stream filter and increases NO2/PM ratio inside the downstream filter. By optimizing the NO2/PM ratio, the downstream filter is boosted to work efficiently at lower temperatures. In contrast, catalytic converter systems typically use a heavily catalyzed catalytic converter upstream of a catalyzed DPF. Such a catalytic converter can consume soluble fraction of particulate matters, but does not affect the concentration of hard carbon soot in the exhaust. Thus, multistage filtration with a catalyzed flow through pre-filter followed by a catalyzed DPF is a better solution with maximized soot-NO2 residence time and minimized NO2 emissions at the tailpipe.
In certain embodiments, the combination of the FTF and the DPF may lead to a filtration efficiency of higher than 92% and NO2/ NOx ratio on a CAT 3126 engine over FTP cycle to 28% which may exhibit a 20% increase of NO2/ NOx percentage across the device from the engine out NO2/ NOx level. Such a device may improve PM filtration efficiency and reduce the system-out NO2 to meet CARB NO2 rule. The primary PM reduction from the FTF can increase the N0x/PM ratio inside the downstream DPF, hence the captured soot oxidized at a relatively lower temperature, leading to lower application criteria.
Figure 1 illustrates an exhaust system 20 that is in accordance with inventive aspects of the present disclosure. The system includes an engine 22 (e.g., a diesel engine) and an exhaust conduit 24 for conveying exhaust gas away from the engine 22. A first diesel particulate reduction device 26 is positioned in the exhaust stream. Downstream from the first diesel particulate reduction device 26 is a second diesel particulate reduction device 28. It will be appreciated that the first diesel particulate reduction device 26 and the second diesel particulate reduction device 28 function together to treat the exhaust gas that passes through the conduit 24. It will also be appreciated that the first diesel particulate reduction device 26 and the second diesel particulate reduction device 28 may be separated by any distance, including being positioned in close proximity or even in direct contact.
The first diesel particulate device 26 is preferably a flow-through filter. Flow-through filters are filters that typically have moderate particulate mass reduction efficiencies. For purposes of this specification, particulate mass reduction efficiency is determined by subtracting the particulate mass that enters the filter from the particulate mass that exits the filter, and by dividing the difference by the particulate mass that enters the filter. The test duration and engine cycling during testing are preferably determined by the Federal Test Procedure (FTP) heavy-duty transient cycle that is currently used for emission testing of heavy-duty on-road engines in the United States (see CFR Title 40, Part 86.1333). A typical flow-through filter has a particulate mass reduction efficiency of 50 percent or less.
Certain flow-through filters do not require all of the exhaust gas traveling through the filter to pass through a filter media having a pore size sufficiently
small to trap particulate material. One embodiment of a flow-through filter includes a plurality of flow-through channels that extend longitudinally from the entrance end to the exit end of the flow-through filter. The flow-through filter also includes filter media that is positioned between at least some of the flow-through channels. The filter further includes flow diversion structures that generate turbulence in the flow-through channels. The flow diversion structures also function to divert at least some exhaust flow from one flow-through channel to another flow-through channel. As the exhaust flow is diverted from one flow- through channel to another, the diverted flow passes through the filter media causing some particulate material to be trapped within the filter media. This flow- through-type filter yields moderate filtration efficiencies, typically up to 50% per filter, with relatively low back pressure.
A catalyst coating (e.g., a precious metal coating) can be provided on the flow-through channels of the flow-through filter to promote the oxidation of the soluble organic fraction (SOF) of the particulate matter to gaseous components and to promote the oxidation of a portion of the nitric oxide (NO) within the exhaust gas to nitrogen dioxide (NO2). Furthermore, the filter media of the flow-through filter captures a portion of the hard carbon particulate matter and a portion of the non-oxidized SOF present in the exhaust. A portion of the net NO2 present, comprising the combination of the NO2 generated by the oxidation catalyst and the NO2 inherently present in diesel exhaust, reacts with the particulate matter trapped on the filter media, according to the reaction NO2 + C = CO (or CO2) + NO. In doing so, the solid particulate matter is converted to a gas, which flows out of the particulate reduction device. To enhance to combustion of carbon at the filter media, the filter media can also be coated with a catalyst (e.g., a precious metal such as platinum).
The first diesel particulate reduction device 26 can also be referred to as an upstream diesel particulate reduction device 26. An example upstream diesel particulate reduction device 26 is shown at Figures 2-5. The device 26 includes a canister 27 housing a substrate (e.g., a honeycomb body) constructed from multiple layers of filtration material 30 sandwiched between layers of corrugated metallic foil 32. The corrugated metallic foil 32 defines elongated passageways 34 (i.e., channels) that are generally parallel to a net flow direction 7 of exhaust gases
through the particulate reduction device. The metallic foil 32 preferably includes structures that generate turbulence for ensuring that mixing occurs within the substrate. In the depicted embodiment, the structures include openings 33 and flow diverting surfaces 35 (i.e., mixing surfaces, deflecting surfaces, mixing shovels, flow diversion structures or like terms). The flow diverting surfaces 35 cause some flow to be diverted within the passageways 34 from the net flow direction 7 to transverse directions 9 and radial directions 11. At least some of the diverted flow travels through the openings 33 between adjacent passageways 34 and through the filtration material 30. As the exhaust flow travels through the filtration material 30, at least some particulate material of the exhaust stream is captured by the filtration material 30. As shown at Figure 5, the diverting surfaces 35 do not completely block/plug the passageways 34. This assists in keeping the pressure drop across the device 26 relatively low.
In one embodiment, the filtration material 30 is a woven-type material constructed from metallic fibers (e.g., a metallic fabric or fleece) which capture particles both by impingement and by blocking their flow. The particle-blocking properties of the filtration material 30 are determined in part by the diameter of the metallic fibers used to construct the fleece. For example, metallic fibers of 20 to 28 microns (millionths of a meter) and 35 to 45 microns have been found to work acceptably. As the exhaust gases flow out of the foil 32 and into the filtration material 30, significant internal turbulence is induced. Of course, types of filtration material other than metallic fleece could also be used
In one embodiment, the device 26 has a diameter of about 10.5 inches and a length of about 3 inches, with 200 cpsi. In certain embodiments, the residence time of the device 26 can be at least 10% or 15% greater than the residence time of a standard straight channel flow-through catalytic converter having the same space velocity.
The space velocity (i.e., the volumetric flow rate of the exhaust gas divided by the volume of the particulate reduction device) of the upstream particulate removal device 26 is greater than the space velocity of the downstream particulate removal device 28. In certain embodiments, the space velocity of the upstream particulate reduction device is equal to at least 2, 3 or 4 times the space velocity of the downstream particulate reduction device for a given volumetric flow rate. In
other embodiments, the space velocity of the upstream particulate reduction device is equal to 2-6 or 3-5 times the space velocity of the downstream particulate reduction device for a given volumetric flow rate. In still other embodiments, the device 26 can have a particulate mass reduction efficiency of 15-50 percent or 20- 50 percent.
In a preferred embodiment, the first diesel particulate reduction device 26 is manufactured by Emitec Gmbh and sold under the name "PM Kat." The device 26 may, however, comprise any flow-through-type construction known to those of skill in the art, such as wire mesh, metallic or ceramic foam. Further details relating to the constructions of the Emitec filters suitable for use as upstream filters can be found at U.S. Patent Application Publication Numbers US 2005/0232830, US 2005/0274012 and US 2005/0229590, which are hereby incorporated by reference in their entireties.
The upstream diesel particulate reduction device 26 also contains a catalyst coating adapted to promote the oxidation of hydrocarbons and the conversion of NO to NO2. Exemplary catalyst coatings include precious metals such as platinum, palladium and rhodium, and other types of components such as alumina, cerium oxide, base metal oxides (e.g., lanthanum, vanadium, etc,) or zeolites. A preferred catalyst for the first particulate reduction device 26 is platinum with a loading level greater than 50 grams/cubic foot of substrate. In other embodiments the platinum loading level is in the range of 50-100 grams/cubic foot of substrate. In a preferred embodiment, the platinum loading is about 70 grams/cubic foot.
In a preferred embodiment, the catalyst coating is available from Intercat, Inc. In one embodiment, the device 26 may exhibit a 27% PM reduction efficiency. In one embodiment, the NO2/ NOx ratio at the out end of the device 26 on a CAT 3126 engine over FTP cycle is around 32%.
The second diesel particulate reduction device 28, also called the downstream diesel particulate reduction device 28, can have a variety of known configurations. As shown at Figure 6, the device 28 is depicted as a wall-flow filter having a substrate 50 housed within an outer casing 52. In certain embodiments, the substrate 50 can have a ceramic (e.g., a foamed ceramic) monolith construction. A mat layer 54 can be mounted between the substrate 50
and the casing 52. Ends 56 of the casing can be bent radially inwardly to assist in retaining the substrate 50 within the casing 52. End gaskets 58 can be used to seal the ends of the device 28 to prevent flow from passing through the mat to by-pass the substrate 50. In one embodiment, the device 28 has a diameter of about 10.5 inches and a length of about 12 inches, with 200 cpsi/12 mil.
Referring to Figure 6, the substrate 50 includes walls 60 defining a honeycomb arrangement of longitudinal passages 62 (i.e., channels) that extend from a downstream end 63 to an upstream end 64 of the substrate 50. The passages 62 are selectively plugged adjacent the upstream and downstream ends 63, 64 such that exhaust flow is forced to flow radially through the walls 60 between the passages 62 in order to pass through the device 28. As shown at Figure 7, this radial wall flow is represented by arrows 66.
An example diesel particulate reduction device is a wall-flow filter having a monolith ceramic substrate including a "honey-comb" configuration of plugged passages as described in United States Patent No. 4,851,015 that is hereby incorporated by reference in its entirety. Example materials for manufacturing the substrate 50 include cordierite, mullite, alumina, SiC, refractory metal oxides, or other materials conventionally used as catalyzed substrates. In a preferred embodiment, the device 28 includes a diesel particulate filter sold by Engelhard Corporation under the name "DPX Filter."
In certain embodiments, the substrate 50 can be coated a catalyst. Exemplary catalysts include precious metals such as platinum, palladium and rhodium, and other types of components such as base metal oxides or rare earth metal oxides. In certain embodiments, the substrate 50 has a platinum loading of 30-80 grams per cubic foot. In a preferred embodiment, the substrate 50 has a platinum loading of about 50 grams per cubic foot, m another embodiment of the diesel particulate reduction device 28, the substrate 50 may have a precious metal loading of about 25 grams per cubic foot, wherein the filter is coated substantially uniformly throughout its length. In one embodiment of the diesel particulate device 28, the substrate 50 may have a precious metal loading between about 5 and 35 grams per cubic foot, wherein the filter is coated substantially uniformly throughout its length.
The upstream particulate reduction device 26 preferably has a higher precious metal loading than the downstream particulate reduction device 28. In certain embodiments, the precious metal loading of the upstream device 26 is at least 10 percent, 20 percent, 30 percent or 40 percent higher than the precious metal loading of the downstream device 28. In other embodiments, the precious metal loading of the upstream device 26 is in the range of 10-80 percent, 20-60 percent or 30-50 percent higher than the precious metal loading of the downstream device 28.
In certain embodiments, catalyst coating of the substrate 50 may be banded with first 2 inches being coated at 48g/ft3 and the last 10 inches being coated at 2g/ft3 for a filter having a length of 12 inches. In this embodiment, the downstream particulate reduction device exhibited a filtration efficiency higher than 85%. In one example operation of the system, the NCV NOx ratio out of the filter on a CAT 3126 engine over FTP cycle was essentially the same as the ratio out of the engine at 8%.
As illustrated in FIG. 6A, in certain embodiments, the downstream device 28 may be zone-coated with a catalyst, wherein the substrate 50 is coated at the ends with a wash coat including a catalyst and is not coated with a wash coat at the middle of the substrate 50. As illustrated in FIG. 6A, first and third zones 71, 73, respectively, are located at the ends of the substrate 50 and are coated with a wash coat. A second, middle zone 72 is positioned between the first and the third zones 71, 73, respectively, and is not coated with a wash coat.
The sizes of the wash coated zones may vary in different embodiments of the filter. For example, in certain embodiments, the first coated zone 71 of the filter 28 may be between about 1/6 and 1/3 of the length of the filter 28 and the third coated zone 73 may be between about 1/6 and 1/3 of the length of the filter 28.
The precious metal loading values may also vary in different embodiments of the filter. In certain embodiments, the precious metal loading of the first zone 71 may be between about 25 and 50 grams/cubic foot and the precious metal loading of the third zone 73 may be between about 5 and 50 grams/cubic foot. In certain embodiments, the overall precious metal loading of the filter 28 may be between about 5 and 35 grams/cubic foot.
In one embodiment, for a filter that is 12 inches in length and 10.5 inches in diameter, the first and the last 3 inches of the device 28 may be wash-coated with a catalyst at a precious metal loading of about 50 grams/cubic foot and the middle 6 inches may be left uncoated. hi such an embodiment, the overall precious metal loading of the filter 28 would be around 25 grams/cubic foot.
In another embodiment, the filter 28 may be zone-coated, but with different levels of loading on the coated portions. For example, for a filter that is 12 inches in length and 10.5 inches in diameter, the first (inlet) 3 inches may be wash coated with 50 grams/cubic foot of precious metal loading and the last (outlet) 3 inches may be coated with 10 grams/cubic foot of precious metal loading and the middle 6 inches may be left uncoated. In such an embodiment, the overall precious metal loading of the filter 28 would be around 15 grams/cubic foot.
Further details of zone-coating of catalysts can be found at U.S. Provisional Patent Application Serial Number 60/835,953, entitled "CRACK RESISTANT SUBSTRATE FOR AN EXHAUST TREATMENT DEVICE", the entire disclosure of which is hereby incorporated by reference.
It should be noted that similar zone-coating techniques for catalysts may be used in the upstream diesel particulate reduction device 26 as well.
The diesel particulate reduction device 28 preferably has a particulate mass reduction efficiency greater than 75%. More preferably, the diesel particulate reduction device 28 has a particulate mass reduction efficiency greater than 85%. Most preferably, the diesel particulate reduction device 28 has a particulate mass reduction efficiency equal to or greater than 90%. It is preferred for the particulate reduction device 28 to have a higher particulate mass reduction efficiency than the particulate reduction device 26. In certain embodiments, the particulate mass reduction efficiency of the device 28 is at least 50, 100, 200, 300, 400 or 500 percent higher than the particulate mass reduction efficiency of the device 26. In other embodiments, the particulate mass reduction efficiency of the device 28 is at least 50-600 or 100-500 or 200-500 percent higher than the particulate mass reduction efficiency of the device 26.
Preferably, to ensure regeneration without excessive NO2 emissions, the ratio of the mass of NO2 to the mass of particulate matter in the exhaust stream between the upstream device 26 and the downstream device 28 is preferably
between 8 and 14. More preferably, this ratio is between 8 and 12. In certain embodiments, it is desirable for the concentration of NO2 between the devices 26, 28 to be in the range of 50-700 parts per million. In other embodiments, the ratio of NO2 to total NOx between the devices 26, 28 is in the range of 20-55 percent or in the range of 30-50 percent. The ratio of NO2 to NOx can be determined by measuring the total amount of NO2 and the total amount OfNOx in the exhaust stream between the upstream and downstream filters, and the dividing the total NO2 by the total NOx to obtain a flow weighted average over a given test period. An example test period and engine cycling protocol during testing are set for by the FTP heavy-duty transient cycle that is currently used for emission testing of heavy-duty on-road engines in the United States.
In operation of the system, a first portion of the particulate matter contained in the diesel exhaust is deposited on the first diesel particulate reduction device 26 in an amount that is a function of the particle capture efficiency of the first diesel particulate reduction device 26. The exhaust gas exits the first diesel particulate reduction device 26 containing a residual portion of particulate matter, defined as the amount of particulate matter not deposited on the first diesel particulate reduction device 26. The exhaust gas thereafter enters the second diesel particulate reduction device 28, where a portion of the particulate matter present in the exhaust gas is deposited on the second diesel particulate reduction device 28 according to the particle capture efficiency of the second diesel particulate reduction device 28.
Simultaneously, as the exhaust gases travel through the first diesel particulate reduction device 26, the SOF portion of particulate matter is oxidized by contact with the oxidation catalyst coating. Furthermore, the NO present within the exhaust stream is converted to NO2 by the oxidation catalyst coating within the first diesel particulate reduction device 26. A portion of this NO2, along with the NO2 inherently present in the exhaust gas, reacts with the particulate matter trapped on the first diesel particulate reduction device 26. By the reaction of NO2 + C = NO + CO or CO2, a portion of the particulate matter is oxidized and converted from a solid carbon form to carbon monoxide or carbon dioxide gas, which thereby exits the particulate reduction device. There is insufficient mass of
soot, however, trapped on the first diesel particulate reduction device 26 to completely consume the NO2 present in the exhaust stream.
Consequently, the exhaust gas exiting the first diesel particulate reduction device 26 contains a residual portion of NO2. This exhaust gas then enters the second diesel particulate reduction device 28 and the NO2 in the exhaust stream reacts with soot on the device 28, converting a portion of the NO2 into NO and regenerating the device 28. In this way, particulate matter is captured and the particulate reduction devices are regenerated while minimizing NO2 emissions. Moreover, the preferred design of the particulate reduction devices create significant internal, three-dimensional, turbulent flow patterns by virtue of the highly tortuous, twisted flow vectors that result from flow impacting into the filtration material 30 and being channeled into and out of the openings in the corrugated foil 32. Other flow-through filter designs such as wire mesh or ceramic or metallic foams produce similar favorable internal turbulence. This internal local turbulence increases the interaction of the exhaust gas with the catalytic coating on the filtration substrate material, thereby promoting the conversion of NO to NO2. Furthermore, this turbulence increases the interaction of the NO2 with the particulate matter trapped on the surfaces of the diesel particulate reduction device. In doing so, the design of the diesel particulate reduction device promotes the consumption of NO2 and the regeneration of the particulate filter.
A number of tests were preformed to provide comparative data between an example system in accordance with the principles of the present disclosure and other systems. The systems tested included system A, system B and system C.
System A is an example of system in accordance with the principles of the present disclosure. System A included an Emitec PM Kat flow-through filter positioned upstream from a wall flow filter. The Emitec filter had a platinum loading of about 70 grams per cubic foot while the wall flow filter had a platinum loading of about 50 grams per cubic foot. The Emitec filter had a diameter of 10 1/2 inches and a length of about 3 inches, and the wall flow filter had a diameter of 10 1/2 inches and a length of about 12 inches. The Emitec filter had a particulate mass reduction efficiency less than 50 percent, while the wall flow filter had a particulate mass reduction efficiency greater than 85 percent.
System B was manufactured by Johnson Matthey, Inc. and sold under the name CCRT. The system included a catalytic converter positioned upstream from a catalyzed wall/flow filter.
System C had the same configuration as System A, except the Emitec filter was loaded with a low NO2 producing catalyst sold by Engelhard. The catalyst includes constituents that inhibit the production of NO2, but allow the oxidation of hydrocarbons. The platinum loading for the low NO2 producing catalyst was also 70 grams per cubic foot.
Systems A, B and C were tested using a caterpillar 3126 diesel engine having 210 horsepower at 2200 rotations per minute. During testing, the engine was cycled according to the parameters set forth under standard FTP heavy-duty transient cycling. Figure 8 shows the FTP transient cycle as a plot of the engine torque and speed over a 20 minute time period. The cycle is divided into 4 phases including the New York Non Freeway (NYNF) phase, the Los Angeles Non Freeway (LANF) phase, the Los Angeles Freeway (LAF) phase and the New York Non Freeway (NYNF) phase.
Figure 9 shows temperature profiles for exhaust generated from the caterpillar 3126 diesel engine during FTP transient cycling. The cycling was done at different torque levels. For example, the 100 percent line represents testing done at torque level that match the standard FTP transient cycle shown at Figure 8. The other profiles were generated by using the same transient cycling, but with the torques lowered a certain percentage relative to the standard torque levels during the federal transient testing protocol. For example, the 85 percent line represents a torque level of 85 percent of the standard torque level specified by the standard FTP transient cycle shown at Figure 8. Similar plot lines are provided for 77%, 70%, 55%, 48% and 40% of the torque levels set by the standard FTP transient cycle. As shown at the graph of Figure 9, at 48% torque, the exhaust temperature is above 2200C for about 37% of the testing duration.
During testing, the percentage OfNO2 relative to the total NOx emitted from the engine was measured for each of the systems between the upstream and downstream exhaust treatment devices. Figure 10 shows the percentage of NO2 relative to total NOx between the afteitreatment devices for each of the systems. The NO2 to NOx percentage is shown across the range of torque levels at which the
federal transient testing protocol was conducted. The graph of Figure 10 shows that System A generated moderate levels OfNO2 (e.g., generally less than 50%), System B generated relatively high levels of NO2 (e.g., generally greater than 60%) and System C generated relatively low levels of NO2 (e.g., generally less than
>%j.
Figure 11 is a graph showing the weight gain on the downstream filters of each of the systems when subjected to federal transient testing protocol cycles at torque levels of 48% for an extended duration. Once again, during testing, a CAT 3126 diesel engine having a 210 horsepower at 2200 RPM was used. During testing, particulate material was emitted from the engine at an average rate of 3.67 grams per hour. As shown by the graph of Figure 11 , System A experienced relatively low weight gain during the testing period. Thus, it can be concluded that a relatively large amount of passive regeneration occurred within the system during the testing period. This regeneration occurred despite the fact that at the 48% torque level, the temperatures of the exhaust gas were relatively low (e.g., the temperature exceeded 2200C less than 40% of the time and almost never exceeded 3000C. In contrast, both Systems B and C experienced substantial weight gain. This indicates that the combination of optimized upstream filtration and NO2 production has significant advantages over systems that merely provide increased NO2 without upstream filtration, or systems that have upstream filtration without generating NO2.
It will be appreciated that the specific dimensions disclosed herein are examples applicable for certain embodiments in accordance with the principles of the disclosure, but that other embodiments in accordance with this disclosure may or may not include such dimensions.
Claims
1. A system for treating diesel exhaust, the system comprising: a first filter including a first substrate having layers of filtration material positioned between layers of corrugated metallic foil, the corrugated metallic foil defining a honeycomb arrangement of longitudinal passageways that extend from an upstream end to a downstream end of the first substrate, the corrugated metallic foil defining openings for allowing exhaust to pass between adjacent longitudinal passageways of the corrugated metallic foil, the filtration material being positioned such that exhaust passing between the adjacent longitudinal passageways passes through the filtration material, the corrugated metallic foil also including flow diverting structures positioned to divert exhaust flow within the longitudinal passageways through the openings; and a second filter positioned downstream from the first filter, the second filter including a second substrate defining a honeycomb arrangement of longitudinal passageways that extend from an upstream end to a downstream end of the second substrate, the longitudinal passages being selectively plugged adjacent upstream and downstream ends of the second substrate such that exhaust flow is forced to flow radially through walls between the longitudinal passages of the second substrate.
2. The system of claim 1, wherein the first filter has a particulate mass reduction efficiency in the range of 15-50 percent, and the second filter has a particulate mass reduction efficiency greater than 75 percent.
3. The system of claim 1, wherein the first and second filters are relatively sized such that in use the space velocity of the first filter is 2-6 times the space velocity of the second filter
4. The system of claim 1, wherein the first and second filters are relatively sized such that in use the space velocity of the first filter is 3-5 times the space velocity of the second filter.
5. The system of claim 1 , wherein the filtration material includes fibers.
6. The system of claim 5, wherein the fibers comprise metallic fibers.
7. The system of claim 1, wherein the first and second filters are each loaded with a precious metal catalyst, and wherein the first filter has a higher precious metal loading than the second filter.
8. A system for treating diesel exhaust, the system comprising: a first filter having a particulate mass reduction efficiency in the range of 15-50 percent; a second filter positioned downstream from the first filter, the second filter having a particulate mass reduction efficiency of at least 75 percent; the first and second filters being relatively sized such that in use the space velocity of the first filter is 2-6 times the space velocity of the second filter; and the first and second filters each being loaded with a precious metal catalyst, the first filter having a higher precious metal loading than the second filter.
9. The system of claim 8, wherein the first filter includes a first substrate having layers of filtration material positioned between layers of corrugated metallic foil, the corrugated metallic foil defining a honeycomb arrangement of longitudinal passageways that extend from an upstream end to a downstream end of the first substrate, the corrugated metallic foil defining openings for allowing exhaust to pass between adjacent longitudinal passageways of the corrugated metallic foil, the filtration material being positioned such that exhaust passing between the adjacent longitudinal passageways passes through the filtration material, the corrugated metallic foil also including flow diverting structures positioned to divert exhaust flow within the longitudinal passageways through the openings.
10. The system of claim 9, wherein the second filter includes a second substrate defining a honeycomb arrangement of longitudinal passageways that extend from an upstream end to a downstream end of the second substrate, the longitudinal passages being selectively plugged adjacent upstream and downstream ends of the second substrate such that exhaust flow is forced to flow radially through walls between the longitudinal passages of the second substrate.
11. The system of claim 10, wherein the filtration material includes fibers.
12. The system of claim 11 , wherein the fibers comprise metallic fibers.
13. The system of claim 8, wherein the second filter includes a substrate defining a honeycomb arrangement of longitudinal passageways that extend from an upstream end to a downstream end of the substrate, the longitudinal passages being selectively plugged adjacent upstream and downstream ends of the second substrate such that exhaust flow is forced to flow radially through walls between the longitudinal passages of the substrate.
14. The system of claim 8, wherein the first and second filters are relatively sized such that in use the space velocity of the first filter is 3-5 times the space velocity of the second filter.
15. The system of claim 8, wherein the second filter has a particulate mass reduction efficiency of at least 85 percent.
16. A method for treating a diesel exhaust stream, the method comprising: initially passing the exhaust stream through a flow-through filter; and subsequently passing the exhaust stream through a wall-flow filter positioned downstream from the flow-through filter.
17. The method of claim 16, wherein the exhaust stream includes NO2 and particulate matter, and wherein the flow-through filter is designed such that the ratio of the mass of the NO2 and the mass of the particulate matter in the exhaust stream is in the range of 8-14 at a location between the flow- though filter and the wall flow filter.
18. The method of claim 16, wherein the exhaust stream includes NO2 and particulate matter, and wherein the flow-through filter is designed such that the ratio of the mass of the NO2 and the mass of the particulate matter in the exhaust stream is in the range of 8-12 at a location between the flow-though filter and the wall flow filter.
Priority Applications (4)
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JP2009501525A JP2009530543A (en) | 2006-03-21 | 2007-03-20 | A system to reduce diesel particulate matter at low temperatures |
EP07753586A EP2002094B1 (en) | 2006-03-21 | 2007-03-20 | Low temperature diesel particulate matter reduction system |
AT07753586T ATE555280T1 (en) | 2006-03-21 | 2007-03-20 | LOW TEMPERATURE SYSTEM FOR REDUCING DIESEL PARTICLES |
CA2647064A CA2647064C (en) | 2006-03-21 | 2007-03-20 | Low temperature diesel particulate matter reduction system |
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US78462106P | 2006-03-21 | 2006-03-21 | |
US60/784,621 | 2006-03-21 |
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Families Citing this family (29)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7862640B2 (en) * | 2006-03-21 | 2011-01-04 | Donaldson Company, Inc. | Low temperature diesel particulate matter reduction system |
DE102006048045A1 (en) * | 2006-10-11 | 2008-04-17 | Daimler Ag | Emission control system for an internal combustion engine |
EP2108075B1 (en) * | 2007-01-12 | 2015-08-12 | Angelo B. Miretti | Explosion protection system with integrated emission control device |
US20090035194A1 (en) * | 2007-07-31 | 2009-02-05 | Caterpillar Inc. | Exhaust treatment system with an oxidation device for NO2 control |
US8166751B2 (en) * | 2007-07-31 | 2012-05-01 | Caterpillar Inc. | Particulate filter |
US9863297B2 (en) * | 2007-12-12 | 2018-01-09 | Basf Corporation | Emission treatment system |
US9993771B2 (en) * | 2007-12-12 | 2018-06-12 | Basf Corporation | Emission treatment catalysts, systems and methods |
US8459017B2 (en) * | 2008-04-09 | 2013-06-11 | Woodward, Inc. | Low pressure drop mixer for radial mixing of internal combustion engine exhaust flows, combustor incorporating same, and methods of mixing |
US8141351B2 (en) * | 2008-04-25 | 2012-03-27 | Cummins Filtration Ip, Inc. | Pre-catalyst for preventing face-plugging on an inlet face of an aftertreatment device and method of the same |
DE102008026178A1 (en) * | 2008-05-30 | 2009-12-03 | Deutz Ag | High efficiency SCR catalyst |
US8276371B2 (en) * | 2008-06-06 | 2012-10-02 | Caterpillar Inc. | Exhaust system having exhaust system segment with improved catalyst distribution and method |
US9009967B2 (en) * | 2008-07-31 | 2015-04-21 | Caterpillar Inc. | Composite catalyst substrate |
WO2010083944A1 (en) * | 2009-01-22 | 2010-07-29 | Man Nutzfahrzeuge Aktiengesellschaft | Device and method for regenerating a particulate filter arranged in the exhaust section of an internal combustion engine |
US20100307138A1 (en) * | 2009-06-04 | 2010-12-09 | Wen-Lo Chen | Diesel engine exhaust purifier |
US8783022B2 (en) * | 2009-08-17 | 2014-07-22 | Donaldson Company, Inc. | Retrofit aftertreatment system for treating diesel exhaust |
US20110067386A1 (en) * | 2009-09-22 | 2011-03-24 | Gm Global Technology Operations, Inc. | Oxidizing Particulate Filter |
US8516804B2 (en) * | 2010-02-26 | 2013-08-27 | Corning Incorporated | Systems and methods for determining a particulate load in a particulate filter |
FR2970295B1 (en) * | 2011-01-11 | 2012-12-28 | Peugeot Citroen Automobiles Sa | EXHAUST LINE FOR AN INTERNAL COMBUSTION ENGINE |
FR2970294B1 (en) * | 2011-01-11 | 2012-12-28 | Peugeot Citroen Automobiles Sa | EXHAUST LINE FOR AN INTERNAL COMBUSTION ENGINE |
US8938954B2 (en) | 2012-04-19 | 2015-01-27 | Donaldson Company, Inc. | Integrated exhaust treatment device having compact configuration |
GB2513364B (en) | 2013-04-24 | 2019-06-19 | Johnson Matthey Plc | Positive ignition engine and exhaust system comprising catalysed zone-coated filter substrate |
GB201207313D0 (en) | 2012-04-24 | 2012-06-13 | Johnson Matthey Plc | Filter substrate comprising three-way catalyst |
US8966880B2 (en) | 2013-03-15 | 2015-03-03 | Paccar Inc | Systems and methods for determining the quantity of a combustion product in a vehicle exhaust |
GB2512648B (en) | 2013-04-05 | 2018-06-20 | Johnson Matthey Plc | Filter substrate comprising three-way catalyst |
US10060632B2 (en) | 2013-10-02 | 2018-08-28 | Samsung Electronics Co., Ltd. | Cooking apparatus and method of controlling the same |
ES2656413T3 (en) * | 2015-12-08 | 2018-02-27 | Jumbomaw Technology Co., Ltd. | Catalytic converter |
GB201704526D0 (en) | 2017-02-21 | 2017-05-03 | Porvair Filtration Group Ltd | Spacer and filtration apparatus containing it |
CN112049715A (en) * | 2020-09-04 | 2020-12-08 | 拓信(台州)精密工业有限公司 | Metal honeycomb carrier with turbulent flow function |
EP4067633A1 (en) * | 2021-03-29 | 2022-10-05 | Andreas Stihl AG & Co. KG | Exhaust silencer, two-stroke engine or four-stroke engine with an exhaust silencer and catalytic converter for an exhaust silencer |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4346557A (en) | 1980-05-07 | 1982-08-31 | General Motors Corporation | Incineration-cleanable composite diesel exhaust filter and vehicle equipped therewith |
Family Cites Families (175)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
BE623896A (en) | 1961-10-23 | |||
US3318128A (en) * | 1964-04-15 | 1967-05-09 | Ford Motor Co | Plaiting |
US3458977A (en) * | 1964-05-19 | 1969-08-05 | Wix Corp | Filters |
GB1301667A (en) | 1969-05-09 | 1973-01-04 | ||
DE10020170C1 (en) * | 2000-04-25 | 2001-09-06 | Emitec Emissionstechnologie | Process for removing soot particles from the exhaust gas of internal combustion engine comprises feeding gas through collecting element, and holding and/or fluidizing until there is sufficient reaction with nitrogen dioxide in exhaust gas |
US3712030A (en) * | 1970-09-14 | 1973-01-23 | J Priest | Exhaust depurator |
US3882677A (en) * | 1973-07-25 | 1975-05-13 | Hrant Eknayan | Pollution minimizing device for internal combustion engines |
GB1531134A (en) * | 1975-08-20 | 1978-11-01 | Atomic Energy Authority Uk | Methods of fabricating bodies and to bodies so fabricated |
GB1557780A (en) | 1976-09-29 | 1979-12-12 | Covrad Ltd | Method and apparatus for forming louvred corrugations in strip or sheet metal |
US4319896A (en) * | 1979-03-15 | 1982-03-16 | Texaco Inc. | Smoke filter rejuvenation system |
US4535588A (en) * | 1979-06-12 | 1985-08-20 | Nippon Soken, Inc. | Carbon particulates cleaning device for diesel engine |
SE437542B (en) * | 1979-10-01 | 1985-03-04 | Tom Ove Artur Rehnberg | PROCEDURE FOR OPTIMIZING DIESEL GAS CLEANING |
US4276071A (en) * | 1979-12-03 | 1981-06-30 | General Motors Corporation | Ceramic filters for diesel exhaust particulates |
DE2951316A1 (en) | 1979-12-20 | 1981-07-02 | Degussa Ag, 6000 Frankfurt | CATALYTIC FILTER FOR DIESEL EXHAUST CLEANING |
US4372111A (en) * | 1980-03-03 | 1983-02-08 | Texaco Inc. | Method for cyclic rejuvenation of an exhaust gas filter and apparatus |
JPS5742317A (en) * | 1980-08-28 | 1982-03-09 | Ngk Insulators Ltd | Ceramic honeycomb filter |
JPS5765813A (en) | 1980-10-09 | 1982-04-21 | Nippon Soken Inc | Purifier for removing particle from exhaust gas of internal combustion engine |
US4416674A (en) | 1980-10-27 | 1983-11-22 | Texaco Inc. | Filter for treating a particle-carrying gaseous stream |
US4404007A (en) | 1980-12-11 | 1983-09-13 | Nippon Soken, Inc. | Exhaust gas cleaning element |
US4451441A (en) * | 1981-01-27 | 1984-05-29 | W. R. Grace & Co. | Method for exhaust gas treatment |
US4464185A (en) * | 1981-03-07 | 1984-08-07 | Nippon Soken, Inc. | Exhaust gas filter |
US4449362A (en) * | 1981-12-02 | 1984-05-22 | Robertshaw Controls Company | Exhaust system for an internal combustion engine, burn-off unit and methods therefor |
AU540009B2 (en) * | 1982-02-16 | 1984-10-25 | Matsushita Electric Industrial Co., Ltd. | Exhaust gas filter |
US4419108A (en) | 1982-02-22 | 1983-12-06 | Corning Glass Works | Filter apparatus and method of filtering |
DE3232729A1 (en) * | 1982-09-03 | 1984-03-08 | Degussa Ag, 6000 Frankfurt | METHOD FOR REDUCING THE IGNITION TEMPERATURE OF DIESEL CARBON FILTERED OUT OF THE EXHAUST GAS FROM DIESEL ENGINES |
US4462812A (en) * | 1982-12-08 | 1984-07-31 | General Motors Corporation | Ceramic monolith particulate trap including filter support |
US4485621A (en) | 1983-01-07 | 1984-12-04 | Cummins Engine Company, Inc. | System and method for reducing particulate emissions from internal combustion engines |
US4686827A (en) * | 1983-02-03 | 1987-08-18 | Ford Motor Company | Filtration system for diesel engine exhaust-II |
US4478618A (en) | 1983-08-01 | 1984-10-23 | General Motors Corporation | Diesel exhaust particulate trap with plural filter tubes |
DE3337903A1 (en) | 1983-10-19 | 1985-05-09 | Werner 7101 Flein Baum | Catalyst arrangement |
DE3407172C2 (en) * | 1984-02-28 | 1986-09-04 | Degussa Ag, 6000 Frankfurt | Device for cleaning exhaust gases from diesel engines |
ATE39853T1 (en) | 1984-04-23 | 1989-01-15 | Engelhard Corp | CATALYTIC EXHAUST FILTER FOR PARTICLES OF A DIESEL ENGINE. |
US5100632A (en) * | 1984-04-23 | 1992-03-31 | Engelhard Corporation | Catalyzed diesel exhaust particulate filter |
USRE33118E (en) | 1984-08-13 | 1989-11-28 | Arvin Industries, Inc. | Exhaust processor |
US4625511A (en) | 1984-08-13 | 1986-12-02 | Arvin Industries, Inc. | Exhaust processor |
CH665002A5 (en) | 1984-11-09 | 1988-04-15 | Bbc Brown Boveri & Cie | METHOD AND DEVICE FOR OPERATING A DIESEL ENGINE WITH AN EXHAUST GAS FILTERING DEVICE. |
US4665690A (en) * | 1985-01-14 | 1987-05-19 | Mazda Motor Corporation | Exhaust gas cleaning system for vehicle |
GB8516420D0 (en) * | 1985-06-28 | 1985-07-31 | Ontario Research Foundation | Diesel particulate traps |
JPH0623535B2 (en) | 1985-10-28 | 1994-03-30 | 日産自動車株式会社 | Exhaust particulate treatment device for internal combustion engine |
DE3545762A1 (en) | 1985-12-21 | 1987-07-02 | Leistritz Maschfabrik Paul | Soot filter |
CA1285493C (en) | 1986-01-06 | 1991-07-02 | Robert Hoch | Method and apparatus for filtering solid particulate matter from diesel engine exhaust |
DE3608635A1 (en) | 1986-03-14 | 1987-09-17 | Drache Keramikfilter | EXHAUST GAS REACTOR AND METHOD FOR THE PRODUCTION THEREOF |
US4695437A (en) | 1986-06-13 | 1987-09-22 | Johnson Matthey, Inc. | Selective catalytic reduction catalysts |
JPS63185425A (en) * | 1987-01-28 | 1988-08-01 | Ngk Insulators Ltd | Ceramic honeycomb filter for cleaning exhaust gas |
US4912776A (en) * | 1987-03-23 | 1990-03-27 | W. R. Grace & Co.-Conn. | Process for removal of NOx from fluid streams |
US4851015A (en) * | 1987-08-21 | 1989-07-25 | Donaldson Company, Inc. | Muffler apparatus with filter trap and method of use |
JPH01159029A (en) * | 1987-12-16 | 1989-06-22 | Toyota Motor Corp | Exhaust gas purification apparatus of diesel engines |
DE3744265C2 (en) | 1987-12-24 | 1996-07-11 | Emitec Emissionstechnologie | Soot filter for exhaust gas cleaning in motor vehicles |
US4916897A (en) * | 1988-01-08 | 1990-04-17 | Toyota Jidosha Kabushiki Kaisha | Exhaust gas purifying apparatus built-in to a muffler for a diesel engine |
US4814081A (en) * | 1988-01-19 | 1989-03-21 | Malinowski Raymond J | Honeycombed filter support disc |
DE3805395A1 (en) * | 1988-02-20 | 1989-08-31 | Man Technologie Gmbh | ELECTROSTATIC DIESEL PARTICLE FILTER |
US4902487A (en) * | 1988-05-13 | 1990-02-20 | Johnson Matthey, Inc. | Treatment of diesel exhaust gases |
US4961314A (en) | 1988-08-15 | 1990-10-09 | Arvin Industries, Inc. | Tuned exhaust processor assembly |
EP0369163A1 (en) | 1988-10-11 | 1990-05-23 | Sakai Chemical Industry Co., Ltd., | Particulate removing catalyst filter and particulate removing method using the same |
DE3837472C2 (en) * | 1988-11-04 | 1998-09-24 | Deutz Ag | Particulate filter system |
JPH02196120A (en) | 1989-01-24 | 1990-08-02 | Nissan Motor Co Ltd | Exhaust particulate processing equipment for internal combustion engine |
US4980137A (en) | 1989-04-03 | 1990-12-25 | Sanitech, Inc. | Process for NOx and CO control |
EP0393257A1 (en) | 1989-04-17 | 1990-10-24 | Emitec Gesellschaft für Emissionstechnologie mbH | Diesel soot filter with an additional arrangement for the reduction of nitrogen oxides and/or the oxidation of carbon monoxide |
DE3923985C1 (en) * | 1989-07-20 | 1990-06-28 | Daimler-Benz Aktiengesellschaft, 7000 Stuttgart, De | |
DE3940758A1 (en) | 1989-12-09 | 1991-06-13 | Degussa | METHOD FOR PURIFYING THE EXHAUST GAS FROM DIESEL ENGINES |
US5243819A (en) | 1989-12-12 | 1993-09-14 | J. Eberspacher | Exhaust gas cleaning device for diesel engines |
DE4002754C2 (en) | 1990-01-31 | 1994-03-17 | Daimler Benz Ag | Filter arrangement used in the supply air flow of a heating or air conditioning system of a motor vehicle |
US5065574A (en) | 1990-05-29 | 1991-11-19 | Caterpillar Inc. | Particulate trap regeneration apparatus and method |
JPH0441914A (en) * | 1990-06-01 | 1992-02-12 | Nissan Motor Co Ltd | Exhaust gas processor for internal combustion engine |
DE4021495A1 (en) * | 1990-07-05 | 1992-01-09 | Schwaebische Huettenwerke Gmbh | EXHAUST FILTER |
US5082479A (en) * | 1990-07-16 | 1992-01-21 | Cummins Engine Company, Inc. | Diesel particulate trap mounting system |
US5212948A (en) * | 1990-09-27 | 1993-05-25 | Donaldson Company, Inc. | Trap apparatus with bypass |
US5248482A (en) | 1991-04-05 | 1993-09-28 | Minnesota Mining And Manufacturing Company | Diesel particulate trap of perforated tubes wrapped with cross-wound inorganic yarn to form four-sided filter traps |
WO1993000503A2 (en) * | 1991-06-27 | 1993-01-07 | Donaldson Company, Inc. | Trap apparatus with tubular filter element |
US5143707A (en) | 1991-07-24 | 1992-09-01 | Mobil Oil Corporation | Selective catalytic reduction (SCR) of nitrogen oxides |
US5169604A (en) | 1991-10-30 | 1992-12-08 | Johnson Matthey, Inc. | Catalytic converter with replaceable carrier assembly |
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 |
JPH05306614A (en) * | 1992-04-28 | 1993-11-19 | Matsushita Electric Ind Co Ltd | Exhaust gas filter and manufacture thereof |
JP2894103B2 (en) * | 1992-09-09 | 1999-05-24 | 松下電器産業株式会社 | Exhaust gas purification device |
US5492679A (en) * | 1993-03-08 | 1996-02-20 | General Motors Corporation | Zeolite/catalyst wall-flow monolith adsorber |
EP0628706A2 (en) | 1993-06-10 | 1994-12-14 | Inco Limited | Catalytic conversion of internal combustion engine exhaust gases |
US5396764A (en) * | 1994-02-14 | 1995-03-14 | Ford Motor Company | Spark ignition engine exhaust system |
JPH07328452A (en) * | 1994-06-13 | 1995-12-19 | Showa Aircraft Ind Co Ltd | Metal carrier for catalyst device |
EP0697505A1 (en) * | 1994-08-02 | 1996-02-21 | Corning Incorporated | In-line adsorber system |
US5787707A (en) * | 1994-08-02 | 1998-08-04 | Corning Incorporated | In-line adsorber system |
US5522218A (en) * | 1994-08-23 | 1996-06-04 | Caterpillar Inc. | Combustion exhaust purification system and method |
JPH0913946A (en) * | 1995-06-28 | 1997-01-14 | Mitsubishi Heavy Ind Ltd | Exhaust gas purifying device with black smoke removing device |
JP3899534B2 (en) | 1995-08-14 | 2007-03-28 | トヨタ自動車株式会社 | Exhaust gas purification method for diesel engine |
JP3434117B2 (en) * | 1996-03-29 | 2003-08-04 | 住友電気工業株式会社 | Particulate trap for diesel engine |
US5711147A (en) * | 1996-08-19 | 1998-01-27 | The Regents Of The University Of California | Plasma-assisted catalytic reduction system |
US5891409A (en) * | 1996-08-19 | 1999-04-06 | The Regents Of The University Of California | Pre-converted nitric oxide gas in catalytic reduction system |
GB9621215D0 (en) | 1996-10-11 | 1996-11-27 | Johnson Matthey Plc | Emission control |
DE19704147A1 (en) * | 1997-02-04 | 1998-08-06 | Emitec Emissionstechnologie | Heat-resistant and regenerable filter body with flow paths |
US5771868A (en) * | 1997-07-03 | 1998-06-30 | Turbodyne Systems, Inc. | Turbocharging systems for internal combustion engines |
GB9717034D0 (en) * | 1997-08-13 | 1997-10-15 | Johnson Matthey Plc | Improvements in emissions control |
DE19736384A1 (en) | 1997-08-21 | 1999-02-25 | Man Nutzfahrzeuge Ag | Method for metering a reducing agent into nitrogen oxide-containing exhaust gas from an internal combustion engine |
DE19755354A1 (en) | 1997-12-12 | 1999-06-17 | Emitec Emissionstechnologie | Metal foil with openings |
GB9802504D0 (en) | 1998-02-06 | 1998-04-01 | Johnson Matthey Plc | Improvements in emission control |
US5996337A (en) | 1998-02-06 | 1999-12-07 | Engelhard Corporation | Dynamic calorimetric sensor system |
GB9804739D0 (en) | 1998-03-06 | 1998-04-29 | Johnson Matthey Plc | Improvements in emissions control |
DE19820971A1 (en) | 1998-05-12 | 1999-11-18 | Emitec Emissionstechnologie | Catalytic converter for purifying the exhaust gas from an I.C. engine |
US6325834B1 (en) | 1998-05-18 | 2001-12-04 | Roberto Fonseca | Exhaust filter and catalyst structure |
DE19823469A1 (en) * | 1998-05-26 | 1999-12-02 | Emitec Emissionstechnologie | Monolithic metallic honeycomb body with varying number of channels |
US6013599A (en) * | 1998-07-15 | 2000-01-11 | Redem Corporation | Self-regenerating diesel exhaust particulate filter and material |
GB9821947D0 (en) * | 1998-10-09 | 1998-12-02 | Johnson Matthey Plc | Purification of exhaust gases |
US6775972B2 (en) * | 1998-10-09 | 2004-08-17 | Johnson Matthey Public Limited Company | Purification of exhaust gases |
JP2002539348A (en) * | 1998-10-12 | 2002-11-19 | ジョンソン、マッセイ、パブリック、リミテッド、カンパニー | Method and apparatus for treating combustion exhaust gas |
ATE224507T1 (en) * | 1998-12-05 | 2002-10-15 | Johnson Matthey Plc | IMPROVEMENTS IN EXHAUST PARTICLE CONTROL |
DE19923781C2 (en) | 1999-05-22 | 2001-04-26 | Degussa | Method and device for removing soot from the exhaust gas of a diesel engine |
GB9913331D0 (en) * | 1999-06-09 | 1999-08-11 | Johnson Matthey Plc | Treatment of exhaust gas |
US6293096B1 (en) | 1999-06-23 | 2001-09-25 | Southwest Research Institute | Multiple stage aftertreatment system |
MXPA02000428A (en) * | 1999-07-02 | 2002-07-02 | Engelhard Corp | Oxidation catalyst for treating diesel engine exhaust gases. |
GB9915939D0 (en) * | 1999-07-08 | 1999-09-08 | Johnson Matthey Plc | Improvements in pollution control |
GB9919013D0 (en) * | 1999-08-13 | 1999-10-13 | Johnson Matthey Plc | Reactor |
US6199375B1 (en) * | 1999-08-24 | 2001-03-13 | Ford Global Technologies, Inc. | Lean catalyst and particulate filter control system and method |
JP2001115822A (en) | 1999-10-19 | 2001-04-24 | Hino Motors Ltd | Particulate filter regenerating device for diesel engine |
DE10004384C2 (en) * | 2000-02-02 | 2003-04-03 | Daimler Chrysler Ag | Arrangement and method for detecting strains and temperatures and their changes on a carrier, in particular one consisting of metal, plastic or ceramic carrier, applied topcoat |
GB0003405D0 (en) | 2000-02-15 | 2000-04-05 | Johnson Matthey Plc | Improvements in emissions control |
US6582490B2 (en) * | 2000-05-18 | 2003-06-24 | Fleetguard, Inc. | Pre-form for exhaust aftertreatment control filter |
US6669913B1 (en) | 2000-03-09 | 2003-12-30 | Fleetguard, Inc. | Combination catalytic converter and filter |
US6776814B2 (en) * | 2000-03-09 | 2004-08-17 | Fleetguard, Inc. | Dual section exhaust aftertreatment filter and method |
JP3566905B2 (en) | 2000-04-17 | 2004-09-15 | 日野自動車株式会社 | Exhaust gas purification device |
US6546721B2 (en) * | 2000-04-18 | 2003-04-15 | Toyota Jidosha Kabushiki Kaisha | Exhaust gas purification device |
DE10024254A1 (en) * | 2000-05-17 | 2001-12-06 | Bosch Gmbh Robert | Exhaust gas treatment device |
DE10026696A1 (en) | 2000-05-30 | 2001-12-20 | Emitec Emissionstechnologie | Particle trap |
GB0013607D0 (en) * | 2000-06-06 | 2000-07-26 | Johnson Matthey Plc | Emission control |
GB0013609D0 (en) * | 2000-06-06 | 2000-07-26 | Johnson Matthey Plc | Emission control |
JP2001355431A (en) | 2000-06-16 | 2001-12-26 | Isuzu Motors Ltd | Exhaust emission control device for diesel engine |
US20030084658A1 (en) * | 2000-06-20 | 2003-05-08 | Brown Kevin F | Process for reducing pollutants from the exhaust of a diesel engine using a water diesel fuel in combination with exhaust after-treatments |
DE10031200A1 (en) * | 2000-06-27 | 2002-01-17 | Emitec Emissionstechnologie | Particle trap for separating particles from the flow of a fluid, method for separating particles from the flow of a fluid and use of a particle trap |
US6673136B2 (en) * | 2000-09-05 | 2004-01-06 | Donaldson Company, Inc. | Air filtration arrangements having fluted media constructions and methods |
JP4889873B2 (en) * | 2000-09-08 | 2012-03-07 | 日産自動車株式会社 | Exhaust gas purification system, exhaust gas purification catalyst used therefor, and exhaust purification method |
JP2002213227A (en) | 2000-11-17 | 2002-07-31 | Toyota Motor Corp | Exhaust emission control system and method for controlling exhaust gas |
JP2002188432A (en) * | 2000-12-19 | 2002-07-05 | Isuzu Motors Ltd | Exhaust gas purifying device for diesel engine |
JP3925154B2 (en) | 2000-12-25 | 2007-06-06 | 株式会社デンソー | Exhaust gas purification filter |
EP1251248A1 (en) | 2001-04-18 | 2002-10-23 | OMG AG & Co. KG | Method and arrangement to remove soot particles from the exhaust gas of a diesel engine |
EP1251249B2 (en) | 2001-04-18 | 2010-06-30 | Umicore AG & Co. KG | A process and device for removing soot particles from the exhaust gas from a diesel engine |
JP3840923B2 (en) * | 2001-06-20 | 2006-11-01 | いすゞ自動車株式会社 | Diesel engine exhaust purification system |
DE10131588B8 (en) * | 2001-07-03 | 2013-11-14 | Daimler Ag | An operating method for an exhaust aftertreatment device comprising a nitrogen oxide storage catalyst downstream of an SCR catalyst and use of the SCR catalyst to remove hydrogen sulfide |
DE20117659U1 (en) * | 2001-10-29 | 2002-01-10 | Emitec Emissionstechnologie | Open particle filter with heating element |
DE10153284A1 (en) | 2001-10-29 | 2003-05-15 | Emitec Emissionstechnologie | Filter assembly and process for its manufacture |
DE20117873U1 (en) * | 2001-11-06 | 2002-02-14 | Emitec Emissionstechnologie | Open filter body with improved flow properties |
US6770252B2 (en) * | 2001-11-21 | 2004-08-03 | General Motors Corporation | Rolling regeneration diesel particulate trap |
US7082753B2 (en) | 2001-12-03 | 2006-08-01 | Catalytica Energy Systems, Inc. | System and methods for improved emission control of internal combustion engines using pulsed fuel flow |
US20030113249A1 (en) | 2001-12-18 | 2003-06-19 | Hepburn Jeffrey Scott | System and method for removing SOx and particulate matter from an emission control device |
US7264785B2 (en) * | 2001-12-20 | 2007-09-04 | Johnson Matthey Public Limited Company | Selective catalytic reduction |
US6813884B2 (en) | 2002-01-29 | 2004-11-09 | Ford Global Technologies, Llc | Method of treating diesel exhaust gases |
DE10207986A1 (en) * | 2002-02-25 | 2003-09-04 | Daimler Chrysler Ag | Emission control system for an internal combustion engine |
GB0218540D0 (en) | 2002-08-09 | 2002-09-18 | Johnson Matthey Plc | Engine exhaust treatment |
GB0220645D0 (en) * | 2002-09-05 | 2002-10-16 | Johnson Matthey Plc | Exhaust system for a lean burn ic engine |
JP2006512534A (en) * | 2002-10-05 | 2006-04-13 | ジョンソン、マッセイ、パブリック、リミテッド、カンパニー | Exhaust mechanism for diesel engine with NOx trap |
JP4172986B2 (en) * | 2002-10-10 | 2008-10-29 | 日本碍子株式会社 | Honeycomb structure, manufacturing method thereof, and exhaust gas purification system using the honeycomb structure |
JP2004162613A (en) * | 2002-11-13 | 2004-06-10 | Mitsubishi Fuso Truck & Bus Corp | Exhaust emission control device for internal combustion engine |
US6928806B2 (en) * | 2002-11-21 | 2005-08-16 | Ford Global Technologies, Llc | Exhaust gas aftertreatment systems |
US6834498B2 (en) * | 2002-11-21 | 2004-12-28 | Ford Global Technologies, Llc | Diesel aftertreatment systems |
DE10254764A1 (en) | 2002-11-22 | 2004-06-03 | Emitec Gesellschaft Für Emissionstechnologie Mbh | exhaust system |
DE10257113A1 (en) | 2002-12-05 | 2004-06-24 | Emitec Gesellschaft Für Emissionstechnologie Mbh | Particle trap with coated fiber layer |
DE10304814C5 (en) | 2003-02-06 | 2009-07-02 | Emitec Gesellschaft Für Emissionstechnologie Mbh | Method and tool for producing structured sheet metal layers; The catalyst support body |
US6766641B1 (en) * | 2003-03-27 | 2004-07-27 | Ford Global Technologies, Llc | Temperature control via computing device |
US6983589B2 (en) * | 2003-05-07 | 2006-01-10 | Ford Global Technologies, Llc | Diesel aftertreatment systems |
DE10321105A1 (en) * | 2003-05-09 | 2004-12-02 | Emitec Gesellschaft Für Emissionstechnologie Mbh | Regeneration of a particle trap |
US7337607B2 (en) | 2003-06-12 | 2008-03-04 | Donaldson Company, Inc. | Method of dispensing fuel into transient flow of an exhaust system |
JP4285096B2 (en) * | 2003-06-16 | 2009-06-24 | 株式会社デンソー | Exhaust gas purification device for internal combustion engine |
GB0314243D0 (en) | 2003-06-18 | 2003-07-23 | Johnson Matthey Plc | Engine exhaust gas treatment |
JP2005048749A (en) * | 2003-07-31 | 2005-02-24 | Nissan Motor Co Ltd | Engine control device |
JP4304447B2 (en) * | 2003-08-29 | 2009-07-29 | いすゞ自動車株式会社 | Exhaust gas purification method and exhaust gas purification system |
JP4333289B2 (en) | 2003-09-03 | 2009-09-16 | いすゞ自動車株式会社 | Exhaust gas purification system |
JP4026576B2 (en) | 2003-10-08 | 2007-12-26 | トヨタ自動車株式会社 | Exhaust gas purification system for internal combustion engine |
US6973776B2 (en) | 2003-11-03 | 2005-12-13 | Ford Global Technologies, Llc | Exhaust gas aftertreatment systems |
US6862881B1 (en) * | 2003-12-05 | 2005-03-08 | Caterpillar Inc | Method and apparatus for controlling regeneration of a particulate filter |
JP2005180262A (en) * | 2003-12-18 | 2005-07-07 | Tetsuo Toyoda | Particulate matter reducing device |
US7021047B2 (en) * | 2004-07-23 | 2006-04-04 | General Motors Corporation | Diesel exhaust aftertreatment device regeneration system |
US7210286B2 (en) * | 2004-12-20 | 2007-05-01 | Detroit Diesel Corporation | Method and system for controlling fuel included within exhaust gases to facilitate regeneration of a particulate filter |
US7340888B2 (en) * | 2005-04-26 | 2008-03-11 | Donaldson Company, Inc. | Diesel particulate matter reduction system |
US20060236680A1 (en) | 2005-04-26 | 2006-10-26 | Wenzhong Zhang | Method for regenerating a diesel particulate filter |
US7216478B2 (en) | 2005-06-03 | 2007-05-15 | Gm Global Technology Operations, Inc. | Exhaust treatment diagnostic using a temperature sensor |
JP4438708B2 (en) * | 2005-07-13 | 2010-03-24 | マツダ株式会社 | Engine fuel injection control device |
US7862640B2 (en) | 2006-03-21 | 2011-01-04 | Donaldson Company, Inc. | Low temperature diesel particulate matter reduction system |
US20080047244A1 (en) | 2006-08-07 | 2008-02-28 | Wenzhong Zhang | Crack Resistant Substrate for an Exhaust Treatment Device |
WO2009028007A1 (en) | 2007-08-24 | 2009-03-05 | Fujitsu Limited | Method for restraining requirements for i/o space of pci device |
-
2007
- 2007-03-19 US US11/725,578 patent/US7862640B2/en active Active
- 2007-03-20 CA CA2647064A patent/CA2647064C/en not_active Expired - Fee Related
- 2007-03-20 WO PCT/US2007/006971 patent/WO2007109294A2/en active Application Filing
- 2007-03-20 JP JP2009501525A patent/JP2009530543A/en not_active Withdrawn
- 2007-03-20 AT AT07753586T patent/ATE555280T1/en active
- 2007-03-20 EP EP07753586A patent/EP2002094B1/en not_active Not-in-force
-
2011
- 2011-01-04 US US12/984,436 patent/US20110185709A1/en not_active Abandoned
-
2012
- 2012-07-16 US US13/550,069 patent/US8808418B2/en active Active
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4346557A (en) | 1980-05-07 | 1982-08-31 | General Motors Corporation | Incineration-cleanable composite diesel exhaust filter and vehicle equipped therewith |
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US20130183215A1 (en) | 2013-07-18 |
US20070240406A1 (en) | 2007-10-18 |
JP2009530543A (en) | 2009-08-27 |
US8808418B2 (en) | 2014-08-19 |
ATE555280T1 (en) | 2012-05-15 |
US7862640B2 (en) | 2011-01-04 |
EP2002094A2 (en) | 2008-12-17 |
CA2647064C (en) | 2014-08-26 |
WO2007109294A3 (en) | 2007-11-08 |
EP2002094B1 (en) | 2012-04-25 |
US20110185709A1 (en) | 2011-08-04 |
CA2647064A1 (en) | 2007-09-27 |
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