EP2058480A1 - Exhaust gas purifying system - Google Patents

Exhaust gas purifying system Download PDF

Info

Publication number
EP2058480A1
EP2058480A1 EP20080165383 EP08165383A EP2058480A1 EP 2058480 A1 EP2058480 A1 EP 2058480A1 EP 20080165383 EP20080165383 EP 20080165383 EP 08165383 A EP08165383 A EP 08165383A EP 2058480 A1 EP2058480 A1 EP 2058480A1
Authority
EP
Grant status
Application
Patent type
Prior art keywords
exhaust
catalyst
reforming
filter
gas
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP20080165383
Other languages
German (de)
French (fr)
Inventor
Yoshifumi Kato
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toyota Industries Corp
Nikkyo Seisakusho KK
Original Assignee
Toyota Industries Corp
Nikkyo Seisakusho KK
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

Links

Images

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/0807Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
    • F01N3/0821Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents combined with particulate filters
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N13/00Exhaust 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
    • F01N13/011Exhaust 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 purifying devices arranged in parallel
    • F01N13/017Exhaust 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 purifying devices arranged in parallel the purifying devices are arranged in a single housing
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N13/00Exhaust 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
    • F01N13/14Exhaust 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 thermal insulation
    • F01N13/141Double-walled exhaust pipes or housings
    • F01N13/145Double-walled exhaust pipes or housings with gas other than air filling the space between both walls
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021Exhaust 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
    • F01N3/023Exhaust 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
    • F01N3/0234Exhaust 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 heat exchange means in the exhaust line
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/0807Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
    • F01N3/0814Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10Exhaust 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
    • F01N3/18Exhaust 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 methods of operation; Control
    • F01N3/20Exhaust 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 methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066Selective catalytic reduction [SCR]
    • F01N3/2073Selective catalytic reduction [SCR] with means for generating a reducing substance from the exhaust gases
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2240/00Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
    • F01N2240/30Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being a fuel reformer

Abstract

An exhaust gas purifying system removes particulate matter from exhaust gas from an engine (1) through an exhaust passage (4). The system includes a filter (5), a reforming catalyst (6) and an injector (8). The filter (5) is provided in the exhaust passage (4) and collects the particulate matter in the exhaust gas. The reforming catalyst (6) is provided in the exhaust passage (4) and is in directly or indirectly contact with the filter (5). The reforming catalyst (6) generates the heat of reaction by reforming fuel. The heat of reaction is transferred to the filter (5) through the contact. The injector (8) supplies the fuel to the reforming catalyst (6).

Description

    BACKGROUND OF THE INVENTION
  • [0001]
    The present invention relates to an exhaust gas purifying system, and more particularly to a system for removing particulate matter from exhaust gas of a diesel engine.
  • [0002]
    In a conventional exhaust gas purifying system, a filter is provided in an exhaust pipe to collect particulate matter in exhaust gas of a diesel engine. In order to prevent particulate matter accumulation on the filter and thereby to prevent an increase in the flow resistance of the filter, particulate matter needs to be removed from the filter so that the filter is regenerated. In a known system, for example, disclosed in Japanese Unexamined Patent Application Publication No. 59-155523 , hydrocarbon is supplied to a filter that contains oxidation catalysts, The hydrocarbons are oxidized or burned off on the filter, thereby removing particulate matter on the filter. The system has a fuel injection unit at an exhaust pipe disposed upstream of the filter with respect to the flow of exhaust gas. The fuel injection unit is connected through a fuel passage to a diesel fuel tank. The fuel passage has a reformer that contains reforming catalysts. The reformer produces hydrocarbons highly reactive with the oxidation catalysts of the filter by reforming diesel fuel. The reformer is connected to a bypass passage branching from the exhaust pipe. Exhaust gas flowing in the exhaust pipe is introduced through the branch passage into the reformer to preheat the reforming catalysts, thereby accelerating the reforming reaction of the diesel fuel in the reforming catalysts.
  • [0003]
    The system disclosed in the reference No. 59-155523 , however, requires two catalytic reactions for removal of particulate matter on the filter, Specifically, the system requires reforming of diesel fuel in the reforming catalyst and oxidation of hydrocarbons in the oxidation catalysts of the filter, which prevents efficient removal of particulate matter from the filter.
  • [0004]
    The present invention is directed to an exhaust gas purifying system that efficiently removes particulate matter from a filter.
  • SUMMARY OF THE INVENTION
  • [0005]
    In accordance with an aspect of the present invention, an exhaust gas purifying system removes particulate matter from exhaust gas from an engine through an exhaust passage. The system includes a filter, a reforming catalyst and an injector. The filter is provided in the exhaust passage and collects the particulate matter in the exhaust gas. The reforming catalyst is provided in the exhaust passage and is in directly or indirectly contact with the filter. The reforming catalyst generates the heat of reaction by reforming fuel. The heat of reaction is transferred to the filter through the contact. The injector supplies the fuel to the reforming catalyst.
  • [0006]
    Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • [0007]
    The features of the present invention that are believed to be novel are set forth with particularity in the appended claims. The invention together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which:
    • Fig. 1 is a schematic view of an exhaust gas purifying system according to a first embodiment of the present invention;
    • Fig. 2 is a longitudinal cross-sectional view of a reformer of the exhaust gas purifying system of Fig. 1;
    • Fig. 3 is a cross-sectional view taken along the line III-III in Fig. 2;
    • Fig. 4 is a longitudinal crass-sectional view of a reformer according to a second embodiment of the present invention;
    • Fig. 5 is a longitudinal cross-sectional view of a reformer according to a third embodiment of the present invention; and
    • Fig. 6 is a cross-sectional view taken along the line VI-VI in Fig. 5.
    DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
  • [0008]
    The following will describe the first embodiment of the present invention with reference to Figs. 1 through 3. Fig. 1 shows an exhaust gas purifying system according to the first embodiment. A diesel engine 1 includes a cylinder head 1A connected to an intake manifold 2 and an exhaust manifold 3. The intake manifold 2 introduces air into the diesel engine 1, and the exhaust manifold 3 emits exhaust gas out of the diesel engine 1. The exhaust manifold 3 is connected to an exhaust pipe 4 as an exhaust passage. Exhaust gas of the diesel engine 1 flows through the exhaust manifold 3 and the exhaust pipe 4, as indicated by arrow A in Fig. 1. The exhaust pipe 4 is connected to a reformer 7 accommodating therein a filter 5 and a reforming catalyst 6 and supplied with diesel fuel from an injector 8. The filter 5 collects particulate matter in exhaust gas (diesel particulate, hereinafter referred to as PM). The reforming catalyst 6 reforms diesel fuel used as a fuel of the diesel engine 1. The injector 8 is connected to a diesel fuel tank (not shown In drawings) through a fuel passage 9 and extends into the reformer 7, thereby injecting diesel fuel into the reformer 7.
  • [0009]
    As shown in Fig. 2, the reformer 7 is a hollow cylindrical case made of a metal and having tapered longitudinal ends connected to the exhaust pipe 4. The reformer 7 has therein a partition wall 7A as a heat transfer member. The partition wall 7A is a hollow cylindrical member made of a metal such as stainless steel and accommodates therein the cylindrical filter 5 so that an outer peripheral surface 5A of the filter 5 is in contact with an inner peripheral surface 7B of the partition wall 7A. That is, the partition wall 7A is in surface contact with the filter 5. The filter 5 is a wall-flow filter having a honeycomb structure formed of a porous ceramic such as cordierite and removes PM from exhaust gas flowing downstream therethrough. The filter 5, the reforming catalyst 6, the reformer 7, the partition wall 7A and the injector 8 are components of the exhaust gas purifying system.
  • [0010]
    The reforming catalyst 6 has a hollow cylindrical shape and disposed outside the partition wall 7A in the reformer 7. An inner peripheral surface 6A of the reforming catalyst 6 is in contact with an outer peripheral surface 7C of the partition wall 7A, and an outer peripheral surface 6B of the reforming catalyst 6 is in contact with an inner peripheral surface 7D of the reformer 7. That is, the partition wall 7A is in surface contact with the reforming catalyst 6. The injector 8 extends into the reformer 7 through an outer peripheral surface 7G and the inner peripheral surface 7D of the reformer 7. The injector 8 is disposed at such a position that allows diesel fuel to be injected upstream of the reforming catalyst 6 in the reformer 7. The reforming catalyst 6 is, for example, a rhodium (Rh) containing catalyst, where diesel fuel is reacted with oxygen (O2) and water vapor (H2O) in exhaust gas, thereby reforming the diesel fuel so as to produce carbon monoxide (CO), hydrogen (H2), and hydrocarbon (HC). This reforming of diesel fuel in the reforming catalyst 6 occurs through exothermic reaction at a temperature of about 700 to 800 degrees Celsius. That is, the reforming catalyst 6 produces the heat of reaction at a temperature of about 700 to 800 degrees Celsius by reforming diesel fuel. The filter 5 is disposed inside the reforming catalyst 6. That is, the filter 5 is surrounded along the entire circumference thereof by the reforming catalyst 6, and the partition wall 7A is in directly contact with the filter 5 and the reforming catalyst 6, as shown in Fig. 3. Therefore, the heat of reaction generated when the reforming catalyst 6 reforms diesel fuel is transferred efficiently to the filter 5 via the partition wall 7A.
  • [0011]
    As shown in Fig. 2, the partition wall 7A has at the upstream end thereof an opening 7E formed between the outer peripheral surface 7C and the inner peripheral surface 7D and extending circumferentially. The partition wall 7A also has at the downstream end an opening 7F formed between the outer peripheral surface 7C and the inner peripheral surface 7D and extending circumferentially. The exhaust gas introduced from the exhaust pipe 4 into the reformer 7 flows mostly in the space surrounded by the partition wall 7A and passes through the filter 5 out of the reformer 7. The rest of the exhaust gas flows through the opening 7E into the space formed between the outer peripheral surface 7C and the inner peripheral surface 7D, passes through the reforming catalyst 6, and then flows through the opening 7F out of the reformer 7 while joining the exhaust gas passing through the filter 5.
  • [0012]
    As described above, the filter 5 and the reforming catalyst 6 are disposed parallel to each other, and the partition wall 7A is in directly contact with the filter 5 and the reforming catalyst 6 to transfer the heat therebetween in the reformer 7. That is, the filter 5 and the reforming catalyst 6 are in indirectly contact with each other, and are in physically contact with each other. Since the thermal conductivity of a solid or the partition wall 7A is larger than that of a gas, the heat of reaction generated at the reforming catalyst 6 is efficiently transferred to the filter 5 via the partition wall 7A. In addition, a part of the exhaust gas introduced into the reformer 7 is branched through the opening 7E and passes through the reforming catalyst 6 provided at the space between the outer peripheral surface 7C and the inner peripheral surface 7D in the reformer 7.
  • [0013]
    Referring to Fig. 1, the reformer 7 is connected at the downstream side thereof to a NOx storage reduction (NSR) catalyst 10, and the NOx storage reduction catalyst 10 is connected at the downstream side thereof to a selective catalytic reduction (SCR) catalyst 11. The NSR catalyst 10 contains therein alkaline earth metals like barium (Ba) as a storage material. In lean exhaust gas, that is, in an oxidizing atmosphere with high oxygen concentration wherein the injector 8 injects no diesel fuel, the NSR catalyst 10 temporarily stores nitrogen oxides (hereinafter referred to as NOx) in the exhaust gas, In rich exhaust gas, that is, in a reducing atmosphere with low oxygen concentration wherein the injector 8 injects diesel fuel, the NSR catalyst 10 releases the stored NOx for reduction to nitrogen (N2) and produces ammonia (NH3), Specifically, NSR catalyst 10 reduces the stored NOx to nitrogen by using carbon monoxide, hydrogen, and hydrocarbon produced by the reforming catalyst 6 as the reducing agent. In the SCR catalyst 11, the remaining NOx in the exhaust gas is reacted with ammonia produced by the NSR catalyst 10, thereby being reduced to nitrogen.
  • [0014]
    The following will describe the operation of the exhaust gas purifying system according to the first embodiment in a lean condition wherein the injector 8 injects no diesel fuel into the reformer 7. As shown in Fig. 1, exhaust gas of the diesel engine 1 flows through the exhaust manifold 3 and the exhaust pipe 4 into the reformer 7. The exhaust gas flows mostly in the space surrounded by the partition wall 7A (see Fig. 2) and passes through the filter 5 out of the reformer 7, so that PM in the exhaust gas is collected by the filter 5. The rest of the exhaust gas flows through the opening 7E into the space between the outer peripheral surface 7C and the inner peripheral surface 7D. The exhaust gas then passes through the reforming catalyst 6, but reforming reaction in the reforming catalyst 6 does not occur because the injector 8 injects no diesel fuel into the reformer 7. After passing through the reforming catalyst 6, the exhaust gas flows through the opening 7F out of the reformer 7.
  • [0015]
    The exhaust gas emitted from the reformer 7 passes through the NSR catalyst 10 and the SCR catalyst 11. Since the injector 8 injects no diesel fuel into the reformer 7, the exhaust gas from the reformer 7 is in the oxidizing atmosphere. Therefore, the NSR catalyst 10 stores NOx in the exhaust gas but produces no ammonia, and no reaction occurs in the SCR catalyst 11. As described above, in the lean condition, PM in exhaust gas is collected by the filter 5, and NOx in the exhaust gas is stored on the NSR catalyst 10. Therefore, exhaust gas emitted out of the system contains neither PM nor NOx.
  • [0016]
    The following will describe the operation of the exhaust gas purifying system according to the first embodiment in a rich condition wherein the injector 8 injects diesel fuel into the reformer 7. When the amount of PM accumulated on the filter 5 becomes a predetermined level, the injector 8 injects diesel fuel into the reformer 7 thereby to supply diesel fuel to the reforming catalyst 6. In the reforming catalyst 6, the diesel fuel is reacted with oxygen in exhaust gas introduced through the opening 7E into the space between the outer peripheral surface 7C and the inner peripheral surface 7D, thereby being reformed so as to produce carbon monoxide. This reforming of diesel fuel in the reforming catalyst 6 occurs through exothermic reaction at a temperature of about 700 to 800 degrees Celsius. Since the partition wall 7A is in directly contact with the filter 5 and the reforming catalyst 6, the heat of reaction generated at the reforming catalyst 6 is efficiently transferred to the filter 5 through the contact, thereby heating the filter 5. When the filter 5 is heated to the PM combustion temperature, the accumulated PM on the filter 5 is burned off, and the filter 5 is regenerated. That is, the heat of reaction generated at the reforming catalyst 6 is used for heating the PM on the filter 5.
  • [0017]
    The exhaust gas introduced into the space between the outer peripheral surface 7C and the inner peripheral surface 7D flows through the opening 7F out of the reformer 7 along with carbon monoxide, hydrogen, and hydrocarbon produced by the reforming catalyst 6. The exhaust gas from the reformer 7 then passes through the NSR catalyst 10. The NSR catalyst 10 releases the NOx previously stored in the oxidizing atmosphere for reduction to nitrogen and produces ammonia, Specifically, NSR catalyst 10 reduces the stored NOx to nitrogen by using carbon monoxide, hydrogen, and hydrocarbon serving as reducing agent produced by the reforming catalyst 6, and produces ammonia. In the SCR catalyst 11, NOx remaining in the exhaust gas that is not reduced in the NSR catalyst 10 is reacted with ammonia produced by the NSR catalyst 10, thereby being reduced to nitrogen.
  • [0018]
    According to the first embodiment, since the partition wall 7A being in directly contact with the filter 5 and the reforming catalyst 6 is provided in the reformer 7, the heat of reaction generated at the reforming catalyst 6 is efficiently transferred to the filter 5 via the partition wall 7A. Therefore, the filter 5 is heated to the PM combustion temperature without using any heating means other than the heat of reaction at the reforming catalyst 6, and the accumulated PM is efficiently removed from the filter 5. Additionally, the heat of reaction at the reforming catalyst 6 is efficiently transferred to the filter 5 because the filter 5 is surrounded along the entire circumference thereof by the reforming catalyst 6. Therefore, the filter 5 is heated to the PM combustion temperature, and the accumulated PM is removed from the filter 5 more efficiently than heretofore.
  • [0019]
    The following will describe an exhaust gas purifying system according to the second embodiment of the present invention. In the second embodiment, the filter is in directly contact with the reforming catalyst without providing a partition wall therebetween as a heat transfer member, but the other components and structures are substantially the same as those of the first embodiment. Therefore, the following description will use the same reference numbers for the common elements or components in both embodiments, and the description of such elements or components in Figs. 1 through 3 for the second embodiment will be omitted. Fig. 4 shows a reformer 17 according to the second embodiment. As with the reformer 7 of the first embodiment, the reformer 17 is provided by a hollow cylindrical case made of a metal. The reformer 17 accommodates therein a hollow cylindrical partition wall 17A so that a downstream end 17B of the partition wall 17A is disposed at a middle position as viewed in longitudinal direction of the reformer 17, thereby being divided radially into two spaces.
  • [0020]
    A cylindrical filter 15 is provided downstream of the partition wall 17A so that an upstream end 15A of the filter 15 is in contact with the downstream end 17B of the partition wall 17A. As with the filter 5 of the first embodiment, the filter 15 is a wall-flow filter and removes PM from exhaust gas flowing downstream therethrough. A hollow cylindrical reforming catalyst 16 is disposed in the space formed between an outer peripheral surface 15B of the filter 15 and an inner peripheral surface 17C of the reformer 17. An inner peripheral surface 16A of the reforming catalyst 16 is in contact with the outer peripheral surface 15B, and an outer peripheral surface 16B of the reforming catalyst 16 is in contact with the inner peripheral surface 17C. That is, the reforming catalyst 16 is in surface contact with the filter 15. In the reforming catalyst 16, as with the reforming catalyst 6 of the first embodiment, diesel fuel is reacted with oxygen and water vapor in the exhaust gas so as to produce carbon monoxide, hydrogen, and hydrocarbon, thereby reforming the diesel fuel. This reforming of diesel fuel in the reforming catalyst 16 occurs through exothermic reaction at a temperature of about 700 to 800 degrees Celsius. That Is, the reforming catalyst 16 produces the heat of reaction at a temperature of about 700 to 800 degrees Celsius by reforming diesel fuel. The heat of reaction generated at the reforming catalyst 16 is directly transferred to the filter 15 in close contact therewith.
  • [0021]
    The partition wall 17A has at the upstream end thereof an opening 17E formed between an outer peripheral surface 17D of the partition wall 17A and the inner peripheral surface 17C and extending circumferentially. The exhaust gas introduced from the exhaust pipe 4 into the reformer 17 flows mostly in the space surrounded by the partition wall 17A and passes through the filter 15 out of the reformer 17, The rest flows through the opening 17E into the space formed between the inner peripheral surface 17C and the outer peripheral surface 17D, passes through the reforming catalyst 16, and then flows out of the reformer 17. According to the second embodiment, since the filter 15 is in directly contact with the reforming catalyst 16, the heat of reaction generated at the reforming catalyst 16 is directly transferred to the filter 15. That is, the heat of reaction generated at the reforming catalyst 16 is used for heating the PM on the filter 15. Therefore, the filter 15 is heated to the PM combustion temperature without using any heating means other than the heat of reaction at the reforming catalyst 16, and the accumulated PM is efficiently removed from the filter 15, as with the first embodiment.
  • [0022]
    The following will describe an exhaust gas purifying system according to the third embodiment of the present invention. Fig. 5 shows a reformer 27 according to the third embodiment, The reformer 27 has a heating member 21 made of a metal such as stainless steel. The heating member 21 is a component of the exhaust gas purifying system. The heating member 21 is composed of a hollow cylindrical frame 21A and a mesh body 21C disposed inside the frame 21A. The heating member 21 is disposed upstream of the filter 5 in the space inside the partition wall 7A so that an outer peripheral surface 21 B of the frame 21 A is in contact with the inner peripheral surface 7B of the partition wall 7A. As shown in Fig. 5, the mesh body 21C has therein a plurality of passages extending in longitudinal direction of the reformer 17 to allow the exhaust gas to flow downstream therethrough. Therefore, the exhaust gas introduced into the space of the partition wall 7A passes through the filter 5 after passing through the mesh body 21C. The partition wall 7A is in directly contact with the reforming catalyst 6 and the heating member 21.
  • [0023]
    According to the third embodiment, the heating member 21 allowing the exhaust gas to flow therethrough is disposed upstream of the filter 5 in the space of the partition wall 7A so that the partition wall 7A is in directly contact with the reforming catalyst 6 and the heating member 21. Therefore, the heating member 21 is heated by the heat of reaction generated at the reforming catalyst 6, thereby increasing the temperature of the exhaust gas passing through the mesh body 21C of heating member 21. That is, the filter 5 disposed downstream of the heating member 21 is heated by the exhaust gas passing through the mesh body 21, as well as by the heat of reaction transferred from the reforming catalyst 6 via the partition wall 7A. Therefore, the filter 5 is heated more efficiently to the PM combustion temperature, and the accumulated PM is removed more efficiently from the filter 5.
  • [0024]
    The above embodiments may be modified in various ways as exemplified below.
  • [0025]
    In the above embodiments, the reformer is divided radially into the two spaces by the partition wall. Alternatively, cylindrical partition walls having different diameters may be concentrically disposed in the reformer so that the filters and the reforming catalysts are disposed alternately, thereby constituting a multilayer structure.
  • [0026]
    In the embodiments, the opening is formed at the partition wall of the reformer, and a part of exhaust gas constantly flows through the upstream opening into the space formed between the outer peripheral surface of the partition wall and the inner peripheral surface of the reformer. Alternatively, the reformer may have a valve operable to open the upstream opening to allow the exhaust gas to flow through the opening only when diesel fuel needs to be reformed.
  • [0027]
    In the first and second embodiments, the filter is surrounded along the entire circumference thereof by the reforming catalyst. Alternatively, the filter may be surrounded along only the partial circumference thereof by the reforming catalyst.
  • [0028]
    Therefore, the present examples and embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein but may be modified within the scope of the appended claims.
  • [0029]
    An exhaust gas purifying system removes particulate matter from exhaust gas from an engine (1) through an exhaust passage (4). The system includes a filter (5), a reforming catalyst (6) and an injector (8). The filter (5) is provided in the exhaust passage (4) and collects the particulate matter in the exhaust gas. The reforming catalyst (6) is provided in the exhaust passage (4) and is in directly or indirectly contact with the filter (5), The reforming catalyst (6) generates the heat of reaction by reforming fuel. The heat of reaction is transferred to the filter (5) through the contact. The injector (8) supplies the fuel to the reforming catalyst (6).

Claims (7)

  1. An exhaust gas purifying system for removing particulate matter from exhaust gas from an engine (1) through an exhaust passage (4), comprising:
    a filter (5) provided in the exhaust passage (4) and collecting the particulate matter in the exhaust gas;
    a reforming catalyst (6) provided in the exhaust passage (4) and generating the heat of reaction by reforming fuel; and
    an injector (8) supplying the fuel to the reforming catalyst (6);
    characterized in that the reforming catalyst (6) is in directly or indirectly contact with the filter (5), so that the heat of reaction generated at the reforming catalyst (6) is transferred to the filter (5).
  2. The exhaust gas purifying system according to claim 1, further comprising a heat transfer member (7A) being in directly contact with the filter (5) and the reforming catalyst (6) to transfer the heat therebetween.
  3. The exhaust gas purifying system according to claim 1 or claim 2, wherein the reforming catalyst (6) circumferentially surrounds the filter (5).
  4. The exhaust gas purifying system according to any one of claims 1 through 3, further comprising a heating member (21) provided upstream of the filter (5) and allowing the exhaust gas to flow downstream therethrough, the heating member (21) receiving the heat of reaction generated at the reforming catalyst (5).
  5. The exhaust gas purifying system according to claim 2, wherein the heat transfer member (7A) is in surface contact with the reforming catalyst (6) and the filter (5).
  6. The exhaust gas purifying system according to claim 5, wherein the heat transfer member (7A) has a hollow cylindrical shape, the reforming catalyst (6) is disposed outside of the heat transfer member (7A), and the filter (5) is disposed inside the heat transfer member (7A).
  7. The exhaust gas purifying system according to claim 2, wherein the heat transfer member is a partition wall (7A) to separate the filter (5) and the reforming catalyst (6).
EP20080165383 2007-11-09 2008-09-29 Exhaust gas purifying system Withdrawn EP2058480A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2007292343A JP2009115064A (en) 2007-11-09 2007-11-09 Exhaust emission control device

Publications (1)

Publication Number Publication Date
EP2058480A1 true true EP2058480A1 (en) 2009-05-13

Family

ID=39971112

Family Applications (1)

Application Number Title Priority Date Filing Date
EP20080165383 Withdrawn EP2058480A1 (en) 2007-11-09 2008-09-29 Exhaust gas purifying system

Country Status (3)

Country Link
US (1) US20090120075A1 (en)
EP (1) EP2058480A1 (en)
JP (1) JP2009115064A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2598741A1 (en) * 2010-07-26 2013-06-05 Westport Power Inc. Fuel processor with mounting manifold

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4881288B2 (en) * 2007-12-13 2012-02-22 本田技研工業株式会社 Exhaust gas purification system for an internal combustion engine
JP5018631B2 (en) * 2008-05-16 2012-09-05 トヨタ自動車株式会社 Exhaust gas purification system for an internal combustion engine
KR101628131B1 (en) * 2010-06-21 2016-06-08 현대자동차 주식회사 Exhaust gas purification system of diesel vehicle
GB201019024D0 (en) * 2010-11-11 2010-12-22 Johnson Matthey Plc Improved reformer
US8745974B2 (en) 2012-01-31 2014-06-10 Caterpillar Inc. Exhaust system
DE102014202291A1 (en) * 2014-02-07 2015-08-13 Volkswagen Aktiengesellschaft Emission control device and motor vehicle with such a

Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59155523A (en) 1983-02-23 1984-09-04 Toyota Motor Corp Filter regenerative apparatus in diesel exhaust fine particulate collecting device
US4535588A (en) * 1979-06-12 1985-08-20 Nippon Soken, Inc. Carbon particulates cleaning device for diesel engine
DE4004424A1 (en) * 1989-02-15 1990-08-16 Steyr Daimler Puch Ag A device for purifying the exhaust gases of diesel engines
DE4207005A1 (en) * 1991-03-06 1992-09-10 Nissan Motor Exhaust gas cleaner for vehicle combustion engine - has parallel arrangement of catalytic converter filter
DE4242496A1 (en) * 1992-12-16 1994-06-23 Daimler Benz Ag Exhaust gas system for combustion engine
DE29808664U1 (en) * 1998-05-15 1998-09-17 Wolfgang Mertner Inh Ing Kurt Filter device, in particular of exhaust gases from diesel internal combustion engines to remove carbon black from carbon black-containing gases
WO2000034630A1 (en) * 1998-12-07 2000-06-15 Stt Emtec Aktiebolag Filter for egr system heated by an enclosing catalyst
US20060153753A1 (en) * 2002-10-29 2006-07-13 Sylvain Mauran Method and device for regenerating a particulate filter for exhaust line, and adapted particulate filter
WO2006104240A1 (en) * 2005-03-28 2006-10-05 Toyota Jidosha Kabushiki Kaisha Exhaust gas purifying system of internal combustion engine
EP1801372A1 (en) * 2005-12-22 2007-06-27 ARK-Holding AG Particulate filter arrangement
US20070256407A1 (en) * 2006-05-05 2007-11-08 Eaton Corporation Reformer temperature control with leading temperature estimation
DE102006032886A1 (en) * 2006-07-15 2008-01-17 Daimler Ag Particle separator and method for the regeneration of a particle
WO2008028061A2 (en) * 2006-09-01 2008-03-06 Emcon Technologies, Llc Apparatus and method for regenerating a particulate filter with a non-uniformly loaded oxidation catalyst
WO2008131573A1 (en) * 2007-04-25 2008-11-06 Hochschule Rapperswil Device and method for regenerating particle filters, use of a medium for regenerating particle filters, and refill pack comprising said medium

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3355661B2 (en) * 1992-10-05 2002-12-09 三菱化学株式会社 Method for producing a catalyst
JP2001073742A (en) * 1999-06-29 2001-03-21 Sumitomo Electric Ind Ltd Particulate trap for diesel engine
JP2001115822A (en) * 1999-10-19 2001-04-24 Hino Motors Ltd Particulate filter regenerating device for diesel engine
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
US6955042B1 (en) * 2004-06-30 2005-10-18 Hydrogensource Llc CPO regenerated lean NOx trap with no moving parts
US7240483B2 (en) * 2004-08-02 2007-07-10 Eaton Corporation Pre-combustors for internal combustion engines and systems and methods therefor

Patent Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4535588A (en) * 1979-06-12 1985-08-20 Nippon Soken, Inc. Carbon particulates cleaning device for diesel engine
JPS59155523A (en) 1983-02-23 1984-09-04 Toyota Motor Corp Filter regenerative apparatus in diesel exhaust fine particulate collecting device
DE4004424A1 (en) * 1989-02-15 1990-08-16 Steyr Daimler Puch Ag A device for purifying the exhaust gases of diesel engines
DE4207005A1 (en) * 1991-03-06 1992-09-10 Nissan Motor Exhaust gas cleaner for vehicle combustion engine - has parallel arrangement of catalytic converter filter
DE4242496A1 (en) * 1992-12-16 1994-06-23 Daimler Benz Ag Exhaust gas system for combustion engine
DE29808664U1 (en) * 1998-05-15 1998-09-17 Wolfgang Mertner Inh Ing Kurt Filter device, in particular of exhaust gases from diesel internal combustion engines to remove carbon black from carbon black-containing gases
WO2000034630A1 (en) * 1998-12-07 2000-06-15 Stt Emtec Aktiebolag Filter for egr system heated by an enclosing catalyst
US20060153753A1 (en) * 2002-10-29 2006-07-13 Sylvain Mauran Method and device for regenerating a particulate filter for exhaust line, and adapted particulate filter
WO2006104240A1 (en) * 2005-03-28 2006-10-05 Toyota Jidosha Kabushiki Kaisha Exhaust gas purifying system of internal combustion engine
EP1801372A1 (en) * 2005-12-22 2007-06-27 ARK-Holding AG Particulate filter arrangement
US20070256407A1 (en) * 2006-05-05 2007-11-08 Eaton Corporation Reformer temperature control with leading temperature estimation
DE102006032886A1 (en) * 2006-07-15 2008-01-17 Daimler Ag Particle separator and method for the regeneration of a particle
WO2008028061A2 (en) * 2006-09-01 2008-03-06 Emcon Technologies, Llc Apparatus and method for regenerating a particulate filter with a non-uniformly loaded oxidation catalyst
WO2008131573A1 (en) * 2007-04-25 2008-11-06 Hochschule Rapperswil Device and method for regenerating particle filters, use of a medium for regenerating particle filters, and refill pack comprising said medium

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2598741A1 (en) * 2010-07-26 2013-06-05 Westport Power Inc. Fuel processor with mounting manifold
EP2598741A4 (en) * 2010-07-26 2014-06-25 Westport Power Inc Fuel processor with mounting manifold

Also Published As

Publication number Publication date Type
US20090120075A1 (en) 2009-05-14 application
JP2009115064A (en) 2009-05-28 application

Similar Documents

Publication Publication Date Title
US6732507B1 (en) NOx aftertreatment system and method for internal combustion engines
US7861516B2 (en) Methods of controlling reductant addition
US20040013580A1 (en) Open filter body with improved flow properties
US7055314B2 (en) System having open particulate filter and heating element, for cleaning exhaust gases from mobile internal combustion engines
US20070012032A1 (en) Hybrid system comprising HC-SCR, NOx-trapping, and NH3-SCR for exhaust emission reduction
US7152396B2 (en) Reductant distributor for lean NOx trap
US20100319324A1 (en) Exhaust Gas Treatment System Including an HC-SCR and Two-way Catalyst and Method of Using the Same
Twigg Roles of catalytic oxidation in control of vehicle exhaust emissions
US20070101703A1 (en) Exhaust emission purifying apparatus for engine
US7188469B2 (en) Exhaust system and methods of reducing contaminants in an exhaust stream
US20060101809A1 (en) Internal combustion engine comprising a reducing agent production unit and operating method therefor
US20080141662A1 (en) Fluid injecting and mixing systems for exhaust after-treatment devices
US20090000287A1 (en) Exhaust Gas Flow Device
US20100175372A1 (en) Compact diesel engine exhaust treatment system
US20100242438A1 (en) Exhaust gas treatment system including a four-way catalyst and urea scr catalyst and method of using the same
WO2001096717A1 (en) Reactor for treating exhaust gas
JP2004060494A (en) Exhaust emission control device of internal combustion engine
US6832473B2 (en) Method and system for regenerating NOx adsorbers and/or particulate filters
US20060260297A1 (en) Exhaust aftertreatment system and method of use for lean burn internal combustion engines
WO2001004466A1 (en) Device and method for removing sooty particulate from exhaust gases from combustion processes
US20100319320A1 (en) Exhaust gas treatment system including a lean nox trap and two-way catalyst and method of using the same
US20110219755A1 (en) Exhaust-gas purification system for diesel engines
JP2005155404A (en) Exhaust emission control device for internal combustion engine
JP2006183507A (en) Exhaust emission control device for internal combustion engine
US20060179822A1 (en) Systems and methods for reducing emissions of internal combustion engines using a fuel processor bypass

Legal Events

Date Code Title Description
AK Designated contracting states:

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR

AX Request for extension of the european patent to

Countries concerned: ALBAMKRS

17P Request for examination filed

Effective date: 20080929

AKX Payment of designation fees

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR

17Q First examination report

Effective date: 20100719

RIC1 Classification (correction)

Ipc: F01N 3/033 20060101ALI20120109BHEP

Ipc: F01N 3/025 20060101ALI20120109BHEP

Ipc: F01N 3/28 20060101ALI20120109BHEP

Ipc: F01N 3/08 20060101AFI20120109BHEP

Ipc: F01N 13/14 20100101ALI20120109BHEP

Ipc: F01N 3/20 20060101ALI20120109BHEP

Ipc: F01N 3/023 20060101ALI20120109BHEP

Ipc: F01N 3/035 20060101ALI20120109BHEP

18D Deemed to be withdrawn

Effective date: 20120403