WO2020071389A1 - Exhaust gas purification device - Google Patents
Exhaust gas purification deviceInfo
- Publication number
- WO2020071389A1 WO2020071389A1 PCT/JP2019/038808 JP2019038808W WO2020071389A1 WO 2020071389 A1 WO2020071389 A1 WO 2020071389A1 JP 2019038808 W JP2019038808 W JP 2019038808W WO 2020071389 A1 WO2020071389 A1 WO 2020071389A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- exhaust gas
- inlet
- outlet
- cell
- gas purifying
- Prior art date
Links
- 238000000746 purification Methods 0.000 title claims abstract description 61
- 238000011144 upstream manufacturing Methods 0.000 claims abstract description 123
- 239000003054 catalyst Substances 0.000 claims abstract description 95
- 238000005192 partition Methods 0.000 claims abstract description 87
- 239000013618 particulate matter Substances 0.000 claims abstract description 80
- 238000002485 combustion reaction Methods 0.000 claims abstract description 46
- 229910000510 noble metal Inorganic materials 0.000 claims abstract description 39
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 claims description 120
- 239000007789 gas Substances 0.000 claims description 108
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 claims description 48
- 239000004332 silver Substances 0.000 claims description 48
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims description 39
- 229910052700 potassium Inorganic materials 0.000 claims description 39
- 239000011591 potassium Substances 0.000 claims description 39
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 35
- 229910052788 barium Inorganic materials 0.000 claims description 30
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 claims description 30
- 229910000420 cerium oxide Inorganic materials 0.000 claims description 27
- BMMGVYCKOGBVEV-UHFFFAOYSA-N oxo(oxoceriooxy)cerium Chemical compound [Ce]=O.O=[Ce]=O BMMGVYCKOGBVEV-UHFFFAOYSA-N 0.000 claims description 27
- 230000001737 promoting effect Effects 0.000 claims description 27
- 239000010410 layer Substances 0.000 claims description 22
- 239000002344 surface layer Substances 0.000 claims description 20
- 229910001923 silver oxide Inorganic materials 0.000 claims description 17
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 51
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical group [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 47
- 239000010948 rhodium Substances 0.000 description 34
- 229910052709 silver Inorganic materials 0.000 description 31
- 229910052703 rhodium Inorganic materials 0.000 description 24
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 24
- 229910052763 palladium Inorganic materials 0.000 description 20
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 description 18
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 description 18
- 239000002585 base Substances 0.000 description 17
- 229910052697 platinum Inorganic materials 0.000 description 16
- 230000003197 catalytic effect Effects 0.000 description 12
- 239000010931 gold Substances 0.000 description 12
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 9
- 230000000694 effects Effects 0.000 description 9
- 239000011701 zinc Substances 0.000 description 9
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 7
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 7
- 229910052737 gold Inorganic materials 0.000 description 7
- 229910052741 iridium Inorganic materials 0.000 description 7
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 7
- 229910052762 osmium Inorganic materials 0.000 description 7
- SYQBFIAQOQZEGI-UHFFFAOYSA-N osmium atom Chemical compound [Os] SYQBFIAQOQZEGI-UHFFFAOYSA-N 0.000 description 7
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- 238000000034 method Methods 0.000 description 6
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- 150000002910 rare earth metals Chemical class 0.000 description 4
- 230000009467 reduction Effects 0.000 description 4
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- 229910052693 Europium Inorganic materials 0.000 description 3
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- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 3
- 229910052769 Ytterbium Inorganic materials 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 3
- KBQHZAAAGSGFKK-UHFFFAOYSA-N dysprosium atom Chemical compound [Dy] KBQHZAAAGSGFKK-UHFFFAOYSA-N 0.000 description 3
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- OGPBJKLSAFTDLK-UHFFFAOYSA-N europium atom Chemical compound [Eu] OGPBJKLSAFTDLK-UHFFFAOYSA-N 0.000 description 3
- UIWYJDYFSGRHKR-UHFFFAOYSA-N gadolinium atom Chemical compound [Gd] UIWYJDYFSGRHKR-UHFFFAOYSA-N 0.000 description 3
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- 229930195733 hydrocarbon Natural products 0.000 description 3
- 150000002430 hydrocarbons Chemical class 0.000 description 3
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- 150000002602 lanthanoids Chemical class 0.000 description 3
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- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 3
- OHSVLFRHMCKCQY-UHFFFAOYSA-N lutetium atom Chemical compound [Lu] OHSVLFRHMCKCQY-UHFFFAOYSA-N 0.000 description 3
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- 230000004048 modification Effects 0.000 description 3
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- QEFYFXOXNSNQGX-UHFFFAOYSA-N neodymium atom Chemical compound [Nd] QEFYFXOXNSNQGX-UHFFFAOYSA-N 0.000 description 3
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- 229910052760 oxygen Inorganic materials 0.000 description 3
- 231100000572 poisoning Toxicity 0.000 description 3
- 230000000607 poisoning effect Effects 0.000 description 3
- PUDIUYLPXJFUGB-UHFFFAOYSA-N praseodymium atom Chemical compound [Pr] PUDIUYLPXJFUGB-UHFFFAOYSA-N 0.000 description 3
- VQMWBBYLQSCNPO-UHFFFAOYSA-N promethium atom Chemical compound [Pm] VQMWBBYLQSCNPO-UHFFFAOYSA-N 0.000 description 3
- KZUNJOHGWZRPMI-UHFFFAOYSA-N samarium atom Chemical compound [Sm] KZUNJOHGWZRPMI-UHFFFAOYSA-N 0.000 description 3
- 229910052706 scandium Inorganic materials 0.000 description 3
- SIXSYDAISGFNSX-UHFFFAOYSA-N scandium atom Chemical compound [Sc] SIXSYDAISGFNSX-UHFFFAOYSA-N 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- GZCRRIHWUXGPOV-UHFFFAOYSA-N terbium atom Chemical compound [Tb] GZCRRIHWUXGPOV-UHFFFAOYSA-N 0.000 description 3
- FRNOGLGSGLTDKL-UHFFFAOYSA-N thulium atom Chemical compound [Tm] FRNOGLGSGLTDKL-UHFFFAOYSA-N 0.000 description 3
- NAWDYIZEMPQZHO-UHFFFAOYSA-N ytterbium Chemical compound [Yb] NAWDYIZEMPQZHO-UHFFFAOYSA-N 0.000 description 3
- 229910052727 yttrium Inorganic materials 0.000 description 3
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 229910052783 alkali metal Inorganic materials 0.000 description 2
- 229910052936 alkali metal sulfate Inorganic materials 0.000 description 2
- 150000001340 alkali metals Chemical class 0.000 description 2
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 2
- 150000001342 alkaline earth metals Chemical class 0.000 description 2
- 229910052792 caesium Inorganic materials 0.000 description 2
- TVFDJXOCXUVLDH-UHFFFAOYSA-N caesium atom Chemical compound [Cs] TVFDJXOCXUVLDH-UHFFFAOYSA-N 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- DRVWBEJJZZTIGJ-UHFFFAOYSA-N cerium(3+);oxygen(2-) Chemical group [O-2].[O-2].[O-2].[Ce+3].[Ce+3] DRVWBEJJZZTIGJ-UHFFFAOYSA-N 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 229910052878 cordierite Inorganic materials 0.000 description 2
- 238000006731 degradation reaction Methods 0.000 description 2
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- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 2
- 229910052730 francium Inorganic materials 0.000 description 2
- KLMCZVJOEAUDNE-UHFFFAOYSA-N francium atom Chemical compound [Fr] KLMCZVJOEAUDNE-UHFFFAOYSA-N 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 229910052705 radium Inorganic materials 0.000 description 2
- HCWPIIXVSYCSAN-UHFFFAOYSA-N radium atom Chemical compound [Ra] HCWPIIXVSYCSAN-UHFFFAOYSA-N 0.000 description 2
- 229910052701 rubidium Inorganic materials 0.000 description 2
- IGLNJRXAVVLDKE-UHFFFAOYSA-N rubidium atom Chemical compound [Rb] IGLNJRXAVVLDKE-UHFFFAOYSA-N 0.000 description 2
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- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
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- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000000295 fuel oil Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 239000010705 motor oil Substances 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- -1 rare earth oxysulfate Chemical class 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
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- 229910001928 zirconium oxide Inorganic materials 0.000 description 1
Images
Classifications
-
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
- B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
- B01J23/46—Ruthenium, rhodium, osmium or iridium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
- B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
- B01J23/56—Platinum group metals
- B01J23/58—Platinum group metals with alkali- or alkaline earth metals
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
- B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
- B01J23/56—Platinum group metals
- B01J23/63—Platinum group metals with rare earths or actinides
-
- B01J35/56—
-
- 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
-
- 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
-
- 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
-
- 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
Definitions
- the present invention relates to an exhaust gas purifying apparatus that collects and burns particulate matter (PM) contained in exhaust gas of an internal combustion engine.
- PM particulate matter
- an exhaust gas purifying apparatus for purifying exhaust gas (exhaust gas) of an internal combustion engine an apparatus for removing harmful components using a carrier carrying a catalyst is known. That is, a catalyst component is fixed inside a carrier having a large number of micropores formed therethrough and exhaust gas is circulated, and carbon monoxide, unburned combustion components, nitrogen oxides, particulate matter contained in the exhaust gas are contained. (PM).
- Examples of the type of the carrier include a ceramic molded product and a metal product (metal carrier).
- the type of the catalyst supported on the carrier is variously selected according to the substance to be purified (see Patent Documents 1 to 3).
- One of the objects of the present invention was created in view of the above-mentioned problems, and it is an object of the present invention to provide an exhaust gas purifying apparatus that efficiently improves exhaust gas purifying performance.
- the disclosed exhaust gas purification apparatus purifies an exhaust gas in which a noble metal is supported inside a partition of a wall flow type carrier having an inlet cell and an outlet cell, and the particulate matter contained in exhaust gas of an internal combustion engine is collected and burned.
- the present apparatus is provided with an inlet upstream portion in which a catalyst is supported on an upstream side of the partition wall surface facing the inlet cell.
- an outlet downstream portion on which a catalyst is supported is provided on a downstream side of the partition wall surface facing the outlet cell.
- the noble metal supported inside the partition include gold (Au), silver (Ag), platinum group elements [ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium ( Ir), platinum (Pt)]. At least one of these is carried inside the partition.
- rhodium (Rh) or palladium (Pd) having a higher catalytic performance than platinum (Pt) is supported inside the partition.
- the inlet upstream portion is provided so as to cover a range from the inlet end face of the carrier to a position shorter than the innermost portion of the inlet cell.
- a portion on which no catalyst is supported is provided on the downstream side of the partition wall surface facing the inlet cell.
- the outlet downstream portion is provided so as to cover a range from the outlet end surface of the carrier to a position closer to the front than the innermost portion of the outlet cell.
- a portion on which no catalyst is supported is provided on the upstream side of the partition wall surface facing the outlet cell.
- the downstream portion of the outlet contains a noble metal.
- the noble metal supported on the downstream of the outlet include gold (Au), silver (Ag), platinum group elements [ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium. (Ir), platinum (Pt)] and the like.
- ruthenium (Ru) rhodium (Rh) or palladium (Pd) having higher catalytic performance than platinum (Pt) is used.
- the upstream portion of the inlet contains silver (Ag) or cerium oxide (CeO 2 ).
- both silver (Ag) and cerium oxide (CeO 2 ) are included in the inlet upstream.
- the upstream portion of the inlet contains a rare earth element.
- the rare earth element here include scandium (Sc), yttrium (Y), lanthanoid [lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium ( Sm), Europium (Eu), Gadolinium (Gd), Terbium (Tb), Dysprosium (Dy), Holmium (Ho), Erbium (Er), Thulium (Tm), Ytterbium (Yb), Lutetium (Lu)] Can be It is preferable that at least one of these is carried in the inlet upstream part.
- the inlet upstream portion contains silver or cerium oxide and a rare earth element
- the inside of the partition contains barium (Ba) or potassium (K) for trapping nitrogen oxides. Barium (Ba) and potassium (K) act as NOx trap catalysts for temporarily adsorbing nitrogen oxides (NOx).
- the inlet upstream portion and the outlet downstream portion are arranged so as to overlap in the vertical direction in a side view.
- the length L 1 of the inlet upstream portion to 60% to the total length L UP of the inlet cells in a side view also the length L 2 of the outlet downstream portion with respect to the total length L DOWN of the outlet cells 60%.
- the preferred length range L 1 of the inlet upstream portion is, for example, 0.5L UP ⁇ L 1 ⁇ 0.75L UP
- preferred length range of L 2 of the outlet downstream portion for example 0.5 L DOWN ⁇ L 2 ⁇ 0.75 L DOWN .
- the disclosed exhaust gas purifying apparatus is an exhaust gas purifying apparatus in which a noble metal is carried inside a partition of a carrier, and the particulate matter contained in exhaust gas of an internal combustion engine is collected and burned.
- a combustion promoting catalyst for promoting the combustion of the particulate matter is supported at a higher density on the upstream side than on the downstream side.
- Specific examples of the combustion promoting catalyst include silver (Ag), cerium oxide (CeO 2 ), silver ceria (Ag / CeO 2 ), tin ceria (Sn / CeO 2 ), and ceria zirconia (CeO 2 / ZrO 2 ). Is mentioned.
- the noble metal supported inside the partition include gold (Au), silver (Ag), platinum group elements [ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium ( Ir), platinum (Pt)]. At least one of these is carried inside the partition.
- rhodium (Rh) or palladium (Pd) having a higher catalytic performance than platinum (Pt) is supported inside the partition.
- the combustion promoting catalyst is carried inside the partition. That is, it is preferable that the combustion promoting catalyst is supported at a high density on the upstream side inside the partition wall.
- the support is a wall flow type support having an inlet cell and an outlet cell, and the combustion promoting catalyst is supported within a range in which a distance to the inlet cell is equal to or less than a predetermined value. For example, when the inside of the partition is partitioned at the center in the thickness direction, it is conceivable to carry the combustion promoting catalyst on the side near the inlet cell.
- inlet upstream portion provided on the upstream side of the partition wall surface of the carrier facing the inlet cell and supporting the combustion promoting catalyst.
- outlet downstream portion provided on the side facing the outlet cell and on the downstream side of the partition wall surface of the carrier and supporting a noble metal.
- inlet upstream portion and the outlet downstream portion are arranged so as to overlap vertically in a side view.
- a nitrogen oxide trap catalyst for trapping nitrogen oxides is included in the partition.
- the nitrogen oxide trap catalyst include alkali metals and alkaline earth metals.
- the nitrogen oxide trap catalyst is supported at a higher density on the downstream side than on the upstream side.
- the nitrogen oxide trap catalyst contains barium and potassium, and the content ratio of potassium relative to the entire nitrogen oxide trap catalyst is set higher on the downstream side than on the upstream side.
- the exhaust gas purification performance can be improved efficiently.
- (A) to (C) are graphs for explaining changes in pressure loss, purification performance, and PM collection efficiency when the catalyst coverage on the inlet cell side is changed. It is sectional drawing which expands and shows the internal structure (A part of FIG. 2) of the support
- 5 is a graph for explaining the distribution of the carrying density of a PM combustion promoting catalyst. 5 is a graph for explaining the distribution of the loading density of the NOx trap catalyst. 4 is a graph for explaining a content ratio of barium and potassium.
- the exhaust gas purifying apparatus 3 of the present application is applied to a vehicle 10 equipped with an engine 1 (internal combustion engine).
- the type of the engine 1 may be a diesel engine or a gasoline engine.
- the exhaust gas purifying apparatus 3 of the present case is suitable for a gasoline engine capable of lean burn operation.
- the exhaust gas purification device 3 is interposed in the exhaust passage 2 of the engine 1.
- the exhaust gas purification device 3 is a catalyst device for efficiently purifying various harmful components contained in exhaust gas, and has a function as a three-way catalyst, a function as a NOx storage reduction catalyst, and a function as a PM removal filter. Have both.
- the disposition position of the exhaust gas purifying device 3 may be set at a position close to the engine 1 (directly downstream of the exhaust manifold or immediately downstream of the supercharger, for example) as shown in FIG. It may be set at a position away from the engine 1. Further, a three-way catalytic converter may be separately provided upstream or downstream of the exhaust gas purifying device 3 to improve the exhaust gas purifying performance.
- a porous body in which a number of flow paths through which the exhaust gas can pass are formed.
- the porous body is obtained by supporting the catalyst 9 on a porous carrier 7 and is formed in a cylindrical shape, an elliptic cylindrical shape, or a rectangular parallelepiped shape.
- the material of the carrier 7 may be a ceramic such as silicon carbide or cordierite (cordierite) or a metal.
- the porosity of the carrier 7 is preferably as high as possible.
- the carrier 7 of the present embodiment has a porosity exceeding 50 [%] and a pore volume of pores having a diameter of 1 [ ⁇ m] or more exceeding 0.2 [mL / g].
- Examples of a base material for supporting the catalyst 9 on the carrier 7 include aluminum oxide (alumina, Al 2 O 3 ), cerium oxide (ceria, CeO 2 ), and zirconium oxide (zirconia, ZrO 2 ).
- an oxygen storage material that stores oxygen in a reducing environment may be included in the base material.
- Examples of the oxygen storage material include a ceria-zirconia composite solid solution (CeO 2 -ZrO 2 -based substance) and rare earth oxysulfate (Ln 2 O 2 SO 4 ).
- the structure of the porous body provided in the exhaust gas purification device 3 is a wall flow type as shown in FIG.
- the inside of the carrier 7 is divided into a plurality of cells (small chamber-like passages) along the flow direction of the exhaust gas, and each cell is partitioned by a porous partition wall 6 (rib). Further, each cell is closed at one end on the inlet side or the outlet side by a plug 8.
- the cell whose outlet end is closed is called an inlet cell 4, and the cell whose inlet end is closed is called an outlet cell 5.
- Each inlet cell 4 is arranged adjacent to at least one or more outlet cells 5, and is preferably arranged adjacent to a number of outlet cells 5.
- the exhaust gas flowing from the inlet end face 11 of the carrier 7 first enters the inlet cell 4, passes through the partition 6, then enters the outlet cell 5, and flows out of the outlet end face 12 of the carrier 7. I do. That is, all the exhaust gas passes through the inside of the partition 6, and the PM collection efficiency is improved.
- the catalyst 9 of a type corresponding to the site is supported on the carrier 7.
- different catalysts 9 are carried between the inside and the surface of the partition 6.
- different catalysts 9 are carried on the inlet cell 4 side and the outlet cell 5 side.
- the inside of the partition 6 is referred to as "partition interior 13".
- a noble metal catalyst is supported in the partition interior 13.
- the noble metal include platinum group elements [platinum (Pt), palladium (Pd), ruthenium (Ru), rhodium (Rh), osmium (Os), iridium (Ir)], gold (Au), silver (Ag) ).
- rhodium or palladium having higher catalytic performance than platinum is used.
- rhodium and palladium have a higher catalytic activity per supported amount (conversion efficiency with respect to total hydrocarbons) than platinum. Therefore, by using rhodium or palladium, the exhaust gas purification performance can be efficiently increased.
- its carrying density is about 1.0 [g / L].
- an inlet upstream portion 14 is provided on the upstream side of the partition wall surface of the carrier 7 facing the inlet cell 4.
- the inlet upstream portion 14 is provided so as to cover a range from the inlet end face 11 to a position closer to the front than the innermost portion of the inlet cell 4. That is, the catalyst is not carried on the downstream side of the inlet upstream portion 14 in the partition wall surface facing the inlet cell 4.
- the length L 1 of the inlet upstream portion 14 in side view satisfies the relationship of at least "0 ⁇ L 1 ⁇ L UP" to the total length L UP inlet cells, preferably "0.5 L UP ⁇ L 1 ⁇ 0.75 L UP ”.
- An outlet downstream portion 15 is provided on the downstream side of the partition wall surface of the carrier 7 facing the outlet cell 5.
- the outlet downstream part 15 is provided so as to cover a range from the outlet end face 12 to a position closer to the front than the innermost part of the outlet cell 5. That is, the catalyst is not carried on the upstream side of the outlet downstream portion 15 in the partition wall surface facing the outlet cell 5.
- the length L 2 of the outlet downstream section 15 in side view satisfies the relationship of at least "0 ⁇ L 2 ⁇ L DOWN" to the total length L DOWN outlet cells, preferably "0.5 L DOWN ⁇ L 2 ⁇ 0.75 L DOWN ”.
- the inlet upstream portion 14 and the outlet downstream portion 15 are arranged so as to overlap in the vertical direction in a side view.
- the length L 2 of the outlet downstream portion 15 is also set to 60% of the total length L DOWN of the outlet cell 5.
- the downstream end of the inlet upstream section 14 and the upstream end of the outlet downstream section 15 are vertically overlapped in FIGS. 2 to 4.
- silver (Ag), cerium oxide (CeO 2 ), or a rare earth element (Rare-Earth Elements, REE) is supported on the inlet upstream portion 14.
- Silver or cerium oxide functions as a PM promoter, and can burn PM at a lower temperature than the noble metal supported in the partition interior 13.
- rare earth elements function as P / Zn traps (phosphorus and zinc traps) and suppress poisoning by phosphorus and zinc contained in exhaust gas.
- its carrying density is about 2.0 [g / L].
- both the former (silver and cerium oxide) and the latter (rare earth) are supported on the inlet upstream portion 14, it is preferable to expose the portion containing silver and cerium oxide to the inlet cell 4 side.
- a portion containing a rare earth element be the base layer 16 and a portion containing silver and cerium oxide be the surface layer 17.
- the surface layer 17 containing silver and cerium oxide may be formed again by the wash coat method.
- rare earth element here include scandium (Sc), yttrium (Y), lanthanoid [lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium ( Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu)] Can be By supporting at least one of these at the inlet upstream portion 14, the P / Zn trap performance is improved.
- a noble metal is carried in the outlet downstream portion 15.
- the noble metal supported on the outlet downstream portion 15 include platinum group elements [platinum, palladium, ruthenium, rhodium, osmium, iridium], gold, silver and the like.
- the type of the noble metal carried here may be the same as or different from that carried on the inside 13 of the partition wall.
- rhodium or palladium is used. When rhodium is used, its loading density is about 0.4 [g / L].
- the partition interior 13 may contain not only a noble metal but also barium (Ba) or potassium (K). Barium and potassium act as a NOx trap that temporarily adsorbs NOx. As shown in FIG. 6, potassium is suitable for NOx purification at a higher temperature than barium, and is suitable for exhaust gas purification in a gasoline engine having a high combustion temperature. Further, potassium has higher NO 2 trapping performance and higher NOx purification efficiency than barium. On the other hand, potassium is thermally unstable and may fall or scatter from the loading position. In this case, the scattered potassium may hinder the catalytic action (ternary activity, especially THC purification performance) of another catalyst or a noble metal. Therefore, it is preferable to use not only potassium but also barium.
- a blank column in the table may be a non-supported catalyst or a certain catalyst (eg, platinum, transition metal sulfate, alkali metal sulfate, etc.). It is assumed that at least the inlet upstream portions 14 of No. 1, No. 6, No. 11, and No. 16 carry some catalyst. Similarly, it is also assumed that some catalyst is carried in the outlet downstream portions 15 of No. 1 to No. 10. If the inlet upstream portion 14 does not contain both silver and cerium oxide and a rare earth element, it is not necessary to form a two-layer structure (forming the base layer 16 and the surface layer 17).
- a certain catalyst eg, platinum, transition metal sulfate, alkali metal sulfate, etc.
- the pressure loss of the exhaust passage can be reduced by providing the inlet upstream portion on the upstream side on the inlet cell side and providing the outlet downstream portion on the downstream side on the outlet cell side. Further, the pressure loss can be reduced while improving the PM collection efficiency, and the exhaust gas purification performance can be efficiently increased. More specifically, the exhaust gas purifying apparatus described above has various functions and effects as described below.
- FIGS. 7A to 7C show that the length L 1 of the inlet upstream portion 14 is fixed to half (50%) of the total length L UP of the inlet cell 4 and the length L 2 of the outlet downstream portion 15 is reduced from zero.
- 10 is a graph showing how the pressure loss, the exhaust gas purification performance, and the PM collection efficiency change when the total length L DOWN of the outlet cell 5 is changed (from 0% to 100%).
- the pressure loss can be suppressed to a small value by the length L 2 of the outlet downstream section 15 below 7-8% of the total length L DOWN. Furthermore, purification performance and PM trapping efficiency is drastically increased by the length L 2 of the outlet downstream section 15 in more than half of the total length L DOWN. Thus, the preferred length range L 2 of the outlet downstream section 15 is considered to 0.5L DOWN ⁇ L 2 ⁇ 0.75L DOWN .
- the broken lines in FIGS. 7A to 7C show the pressure loss, the exhaust gas purification performance, and the PM collection efficiency when the amount of the noble metal supported on the inside 13 of the partition wall is increased. As described above, even when the outlet downstream portion 15 is not formed in a wide range over the entire length L DOWN of the outlet cell 5, good exhaust gas purification performance can be maintained by adjusting the amount of noble metal carried in the partition interior 13.
- FIGS. 8A to 8C show that the length L 2 of the outlet downstream portion 15 is fixed to half (50%) of the total length L DOWN of the outlet cell 5 and the length L 1 of the inlet upstream portion 14 is changed from zero.
- 6 is a graph showing how the pressure loss, the exhaust gas purification performance, and the PM collection efficiency change when the total length L UP of the inlet cell 4 is changed (from 0% to 100%). It is possible to suppress the pressure loss by the length L 1 of the inlet upstream section 14 below 7-8% of the total length L DOWN. Furthermore, purification performance and PM trapping efficiency is rapidly increased by the length L 1 of the inlet upstream section 14 to more than half of the total length L UP. Thus, the preferred length range L 1 of the inlet upstream section 14 is considered to 0.5L UP ⁇ L 1 ⁇ 0.75L UP .
- the pressure loss of the exhaust passage 2 is reduced by providing the inlet upstream section 14 on the upstream side of the inlet cell 4 side of the surface of the partition wall 6 and providing the outlet downstream section 15 on the downstream side of the outlet cell 5 side. be able to. Further, the pressure loss can be reduced while improving the PM collection efficiency, and the exhaust gas purification performance can be efficiently increased. Note that, on the partition wall surface facing the inlet cell 4, no catalyst is supported downstream of the inlet upstream portion 14. Similarly, the catalyst is not carried on the upstream side of the outlet downstream portion 15 in the partition wall surface facing the outlet cell 5. These “catalyst non-supporting portions” function as flow paths having a small exhaust gas flow resistance and a small pressure loss. Therefore, pressure loss can be reduced with a simple configuration.
- the NOx reduction efficiency at the outlet cell 5 side can be increased by including the noble metal catalyst in the outlet downstream portion 15.
- the amount of slip of NOx from the exhaust gas purification device 3 can be reduced, and the exhaust gas purification performance can be efficiently increased.
- silver or cerium oxide is contained in the inlet upstream section 14. By doing so, the combustion of PM can be promoted, and the PM can be burned at a lower temperature than the inside 13 of the partition wall. This makes it possible to regenerate the carrier 7 more quickly and in a shorter time than before, and it is possible to efficiently improve exhaust gas purification performance. In addition, an increase in pressure loss due to deposition of PM can be prevented.
- the PM upstream efficiency and the exhaust gas purification efficiency can be increased by vertically overlapping the inlet upstream section 14 and the outlet downstream section 15 in a side view.
- the length L 1 of the inlet upstream section 14 and sets in the range of 0.5L UP ⁇ L 1 ⁇ 0.75L UP
- the length L 2 of the outlet downstream section 15 0.5L DOWN ⁇ L 2 ⁇ 0.75L DOWN 7 and 8
- the purification performance and the PM collection efficiency can be maintained at high levels without excessively increasing the pressure loss.
- the exhaust gas purifying device described above can achieve the object of reducing pressure loss while improving PM collection efficiency. It is to be noted that the above-described exhaust gas purifying apparatus is not limited to this object, and has the function and effect derived from each configuration shown in the “Embodiment for Carrying Out the Invention”. Can be positioned as other purposes.
- FIG. 9 illustrates a structure of the exhaust gas purifying apparatus 3 of the present embodiment.
- the partition interior 13 is classified into two regions, a side near the entrance cell 4 and a side near the exit cell 5.
- the former is a portion where the distance to the partition wall surface (or the inlet cell 4) on the entrance cell 4 side is equal to or less than a predetermined value T, and the latter is a portion where the distance to the entrance cell 4 exceeds the predetermined value T.
- the value of the predetermined value T is arbitrary, and is set, for example, so as to satisfy the relationship of “T ⁇ 0.5 T WALL ”, where the thickness of the partition wall 6 is T WALL .
- the side of the partition interior 13 that is closer to the inlet cell 4 is referred to as “inner inlet side 18”, and the side closer to the outlet cell 5 is referred to as “inner outlet side 19”.
- Different catalyst layers are formed on the surface of the partition 6 on the inlet cell 4 side and the outlet cell 5 side.
- an inlet upstream portion 14 is provided on the upstream side of the partition wall surface of the carrier 7 facing the inlet cell 4.
- the inlet upstream portion 14 is provided so as to cover a range from the inlet end face 11 to a position closer to the front than the innermost portion of the inlet cell 4. That is, the catalyst 9 is not carried on the outlet end face 12 side of the inlet upstream portion 14 in the partition wall surface facing the inlet cell 4.
- the length L 1 of the inlet upstream portion 14 in side view satisfies the relationship of at least "0 ⁇ L 1 ⁇ L UP" to the total length L UP inlet cells, preferably "0.5 L UP ⁇ L 1 ⁇ 0.75 L UP ”.
- the inlet upstream section 14 may have a multilayer structure including the base layer 16 and the surface layer 17.
- the surface layer 17 is the surface of the inlet upstream portion 14 in contact with the inlet cell 4 or a portion close to the surface (a portion where the distance to the surface is equal to or less than a second predetermined value).
- the base layer 16 is a portion located closer to the carrier 7 than the surface layer 17, and is preferably provided so as to be in contact with the carrier 7.
- a portion other than the surface layer 17 is the base layer 16. In such a multilayer structure, it is preferable to support different catalysts 9 on the base layer 16 and the surface layer 17.
- An outlet downstream portion 15 is provided on the downstream side of the partition wall surface of the carrier 7 facing the outlet cell 5.
- the outlet downstream part 15 is provided so as to cover a range from the outlet end face 12 to a position closer to the front than the innermost part of the outlet cell 5. That is, the catalyst 9 is not carried on the inlet end face 11 side of the outlet downstream portion 15 in the partition wall surface facing the outlet cell 5.
- the length L 2 of the outlet downstream section 15 in side view satisfies the relationship of at least "0 ⁇ L 2 ⁇ L DOWN" to the total length L DOWN outlet cells, preferably "0.5 L DOWN ⁇ L 2 ⁇ 0.75 L DOWN ”.
- the inlet upstream portion 14 and the outlet downstream portion 15 are arranged so as to overlap in the vertical direction in a side view.
- the length L 2 of the outlet downstream portion 15 is also set to 60% of the total length L DOWN of the outlet cell 5.
- the downstream end portion of the inlet upstream portion 14 and the upstream end portion of the outlet downstream portion 15 overlap each other in the vertical direction in FIGS.
- a noble metal catalyst is supported in the partition interior 13.
- the noble metal include platinum group elements [platinum (Pt), palladium (Pd), ruthenium (Ru), rhodium (Rh), osmium (Os), iridium (Ir)], gold (Au), and silver (Ag). ).
- platinum group elements platinum group elements [platinum (Pt), palladium (Pd), ruthenium (Ru), rhodium (Rh), osmium (Os), iridium (Ir)], gold (Au), and silver (Ag).
- rhodium or palladium having higher catalytic performance than platinum is used.
- rhodium and palladium have a higher catalytic activity per supported amount (conversion efficiency with respect to total hydrocarbons) than platinum. Therefore, by using rhodium or palladium, the exhaust gas purification performance can be efficiently increased.
- its carrying density is about 1.0 [g / L].
- silver and cerium oxide function as a PM combustion promoting material (combustion promoting catalyst), and can burn PM at a lower temperature than the noble metal supported in the partition wall interior 13.
- combustion promoting materials include tin ceria (Sn / CeO 2 ) and ceria zirconia (CeO 2 / ZrO 2 ).
- rare earth elements function as P / Zn traps (phosphorus and zinc traps) and suppress poisoning by phosphorus and zinc contained in exhaust gas.
- its carrying density is about 2.0 [g / L].
- both the former (silver, cerium oxide, silver ceria) and the latter (rare earth) are supported on the inlet upstream section 14, it is preferable to expose the part containing the former to the inlet cell 4 side.
- a portion containing a rare earth element be the base layer 16 and a portion containing silver, cerium oxide, and silver ceria be the surface layer 17.
- the surface layer 17 containing silver, cerium oxide and silver ceria may be formed again by the wash coat method.
- the inlet upstream portion 14 may have a single-layer structure instead of a multilayer structure. Good.
- rare earth element here include scandium (Sc), yttrium (Y), lanthanoid [lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium ( Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu)] Can be By supporting at least one of these at the inlet upstream portion 14, the P / Zn trap performance is improved.
- a noble metal is carried in the outlet downstream portion 15.
- the noble metal supported on the outlet downstream portion 15 include platinum group elements [platinum, palladium, ruthenium, rhodium, osmium, iridium], gold, silver and the like.
- the type of the noble metal carried here may be the same as or different from that carried on the inside 13 of the partition wall.
- rhodium or palladium is used. When rhodium is used, its loading density is about 0.4 [g / L].
- the NOx trap catalyst (nitrogen oxide trap catalyst) that temporarily stores and adsorbs NOx may be included in the partition interior 13.
- Specific examples of the NOx trap catalyst include an alkali metal and an alkaline earth metal.
- barium (Ba), potassium (K), rubidium (Rb), strontium (Sr), cesium (Cs), francium (Fr), radium (Ra) and the like are preferable, and barium and potassium are preferably used in combination.
- potassium is suitable for NOx purification at a higher temperature than barium, and is suitable for exhaust gas purification in a gasoline engine having a high combustion temperature. Further, potassium has higher NO 2 trapping performance and higher NOx purification efficiency than barium. On the other hand, potassium is thermally unstable and may fall or scatter from the loading position. In this case, the scattered potassium may hinder the catalytic action (ternary activity, particularly THC purification performance) of another catalyst or a noble metal. Therefore, it is preferable to use barium and potassium together.
- Tables 3 to 10 below show combinations of the type of the catalyst 9 and the supporting position.
- 64 types of embodiments No. 21 to No. 84
- “Pd / Rh” in the table means that palladium and rhodium are included.
- the noble metal is contained in the partition interior 13.
- “Ag / CeO 2 ” in the table means that it contains silver ceria which is a PM combustion promotion catalyst. The silver ceria is carried on the inside of the partition wall 13 and on the inlet upstream portion 14 (Nos. 22 to 36, 38 to 52, 54 to 68, 70 to 84).
- ⁇ " Ba / K in the table means that it contains barium and potassium. Barium and potassium are supported in the partition interior 13, preferably at least on the internal outlet side 19 (Nos. 53 to 84). “REE” in the table means that rare earth elements are included. The rare earth element is carried in the inlet upstream portion 14 (Nos. 23 to 24, 27 to 28, 31 to 32, 35 to 36, 39 to 40, 42 to 44, 47 to 48, 51 to 52, 55 to 56). , 59-60, 63-64, 67-68, 71-72, 75-76, 79-80, 83-84). If the entrance upstream portion 14 does not contain both silver ceria and a rare earth element, it is not necessary to form a two-layer structure (forming the base layer 16 and the surface layer 17).
- a catalyst may not be supported, or some catalyst (for example, platinum, transition metal sulfate, alkali metal sulfate, etc.) may be supported.
- some catalyst for example, platinum, transition metal sulfate, alkali metal sulfate, etc.
- some PM combustion promoting catalyst for example, silver (Ag), cerium oxide (CeO 2 ), tin ceria (Sn / CeO 2 ) and ceria zirconia (CeO 2 / ZrO 2 ). Therefore, all embodiments include some PM combustion promoting catalyst on the support 7.
- Examples that do not include barium and potassium are described in Tables 3-6, and examples that include barium and potassium are described in Tables 7-10.
- Examples in which the outlet downstream portion 15 does not include a noble metal are described in Tables 3 and 4, and examples in which the outlet downstream portion 15 includes a noble metal are described in Tables 5 to 10.
- Examples in which silver ceria is not included in the internal outlet side 19 are described in Tables 3, 5, 7, and 9; examples in which silver ceria is included in the internal outlet side 19 are shown in Tables 4, 6, and 6. It is described in Tables 8 and 10.
- the PM combustion promoting catalyst is supported at a higher density on the upstream side than on the downstream side.
- the upstream side and the downstream side are an upstream (distribution source) and a downstream (distribution destination) based on the flow direction of the exhaust gas.
- the following (A) to (G) can be considered.
- the carrier In the inlet upstream portion 14, the carrier is supported at a higher density on the surface layer 17 (upstream side) than on the base layer 16 (downstream side).
- the carrier In the partition interior 13, the carrier is carried at a higher density on the inner inlet side 18 (upstream side) than on the inner outlet side 19 (downstream side).
- the support In the upstream part 14 of the inlet and the inside 13 of the partition wall, the support is carried out such that the carrying density becomes lower in the order of the surface layer 17, the base layer 16, the inner inlet side 18, and the inner outlet side 19.
- FIG. 10 is a graph showing a setting example of the carrying density of the PM combustion promoting catalyst.
- the broken lines in FIG. 10 correspond to the settings according to the above (A) and (D).
- the dashed line in FIG. 10 corresponds to the setting according to the above (B) and (F), and the thick solid line corresponds to the setting according to the above (C) to (G).
- the PM combustion promoting catalyst carried on the upstream side where the PM tends to accumulate higher than on the downstream side, the PM is uniformly burned on the upstream side and the downstream side of the carrier 7. It will be easier. This makes it easier for the PM accumulated at various places of the carrier 7 to be incinerated in the same incineration time, thereby preventing local excessive temperature rise.
- the NOx trap catalyst may be supported at a higher density on the downstream side than on the upstream side.
- Specific methods for setting the loading density of the NOx trap catalyst include, for example, the following (H) to (J).
- the carrier In the partition interior 13, the carrier is carried at a higher density on the internal outlet side 19 (downstream side) than on the internal inlet side 18 (upstream side).
- the carrier On the inner outlet side 19, the carrier is carried at a higher density in a portion (downstream side) closer to the outlet cell 5 than in a portion (upstream side) farther from the outlet cell 5.
- a higher density On the inner inlet side 18, a higher density is carried at a portion (downstream side) farther from the inlet cell 4 than at a portion (upstream side) closer to the inlet cell 4.
- FIG. 11 is a graph showing a setting example of the carrying density of the NOx trap catalyst.
- the dashed line in FIG. 11 corresponds to the setting according to the above (H)
- the dashed line corresponds to the setting according to the above (H) to (I)
- the solid line is the above (H) to (J).
- the content ratio of barium and potassium may be different for each part of the carrier 7 as shown in FIG. That is, the barium content may be set high on the upstream side and low on the downstream side. In other words, the potassium content may be set low on the upstream side and high on the downstream side. Such a setting suppresses a decrease in other catalytic action due to the scattering of potassium.
- the distribution of PM collected on the carrier is not necessarily uniform, and a deviation occurs depending on the shape of the carrier, the flow of exhaust gas, and the like.
- PM easily accumulates on the surface of the carrier facing the inlet cell or near the inlet of the exhaust gas flow path inside the carrier. Therefore, there is a problem that it is difficult to burn PM uniformly on the upstream side and the downstream side of the carrier. It should be noted that the incineration time is prolonged more easily on the upstream side where the deposition amount of PM tends to increase, and there is a risk of performance degradation due to excessive heating.
- the PM (particulate matter) can be efficiently burned by supporting the combustion promoting catalyst at a high density on the upstream side, and the purification efficiency of PM and the purification efficiency of exhaust gas can be improved efficiently. Can be enhanced. More specifically, the exhaust gas purifying apparatus described above has various functions and effects as described below.
- FIG. 7 (A) ⁇ (C) observed the relationship shown in FIG. 8 (A) ⁇ (C) , preferably the length L 2 range of outlet downstream section 15 0.5L It is considered that DOWN ⁇ L 2 ⁇ 0.75L DOWN . Even when the outlet downstream portion 15 is not formed in a wide area over the entire length L DOWN of the outlet cell 5, good exhaust gas purification performance can be maintained by adjusting the amount of noble metal carried in the partition interior 13. Also preferred length range L 1 of the inlet upstream section 14 is considered to be 0.5L UP ⁇ L 1 ⁇ 0.75L UP .
- the PM combustion promotion catalyst is supported on the inside 13 of the partition wall to deposit it on the inside 13 of the partition wall.
- the burned PM can be burned at a lower temperature. Therefore, PM combustion efficiency can be improved, and clogging and pressure loss increase due to PM can be prevented.
- the PM combustion efficiency can be further increased by supporting the PM combustion promoting catalyst on the inner inlet side 18 where PM easily accumulates inside the partition wall 13.
- the PM combustion promoting catalyst can be carried in the inlet upstream portion 14 having the highest probability of contact with PM in the exhaust gas, so that the PM combustion efficiency can be further improved. Temperature. Further, the PM can be burned before entering the partition interior 13, and the pressure loss in the exhaust passage 2 can be reduced. Therefore, comprehensive exhaust gas purification performance can be improved.
- the NOx reduction efficiency on the outlet cell 5 side can be increased by including a noble metal catalyst in the outlet downstream portion 15. As a result, the amount of slip of NOx from the exhaust gas purification device 3 can be reduced, and the exhaust gas purification performance can be efficiently increased.
- the PM upstream efficiency and the exhaust gas purification efficiency can be increased by vertically overlapping the inlet upstream portion 14 and the outlet downstream portion 15 in a side view.
- the length L 1 of the inlet upstream section 14 and sets in the range of 0.5L UP ⁇ L 1 ⁇ 0.75L UP
- the length L 2 of the outlet downstream section 15 0.5L DOWN ⁇ L 2 ⁇ 0.75L DOWN 7 and 8
- the purification performance and the PM collection efficiency can be maintained at high levels without excessively increasing the pressure loss.
- the above exhaust gas purifying device can achieve the purpose of burning PM uniformly. It is to be noted that the above-described exhaust gas purifying apparatus is not limited to this object, and has the function and effect derived from each configuration shown in the “Embodiment for Carrying Out the Invention”. Can be positioned as other purposes.
- the vehicle 10 equipped with the engine 1 is illustrated, but the application target of the present invention is not limited to the vehicle 10.
- the above-mentioned exhaust gas purifying device 3 can be interposed in the exhaust passage 2 of the engine 1 mounted on a ship or an aircraft, for example. Alternatively, it can be used as an exhaust gas purifying device 3 of the engine 1 built in a generator or an industrial machine.
Abstract
In an exhaust gas purification device (3) for collecting and burning particulate matter contained in exhaust gas from an internal combustion engine (1), noble metal is made to be supported inside a partition wall of a wall flow type carrier (6) having an inlet cell (4) and an outlet cell (5). An inlet upstream section (14) on which a catalyst is supported is provided upstream of the side of a partition wall surface, which faces the inlet cell (4). An outlet downstream section (15) on which a catalyst is supported is provided downstream of the side of the partition wall surface, which faces the outlet cell (5). As a result, exhaust gas purification performance is efficiently enhanced.
Description
本発明は、内燃機関の排ガスに含まれる粒子状物質（PM）を捕集して燃焼させる排ガス浄化装置に関する。
The present invention relates to an exhaust gas purifying apparatus that collects and burns particulate matter (PM) contained in exhaust gas of an internal combustion engine.
従来、内燃機関の排ガス（排気ガス）を浄化するための排ガス浄化装置として、触媒が担持された担体を用いて有害成分を除去するものが知られている。すなわち、多数の微細孔が貫通形成された担体（キャリア）の内部に触媒成分を固定して排ガスを流通させ、排ガス中に含まれる一酸化炭素，未燃燃焼成分，窒素酸化物，粒子状物質（Particulate Matter；以下PM）などを浄化するものである。担体の種類としては、セラミックス成形品や金属製品（メタル担体）などが存在する。また、担体に担持される触媒の種類は、浄化の対象となる物質に応じて多様に選択される（特許文献１～３参照）。
Conventionally, as an exhaust gas purifying apparatus for purifying exhaust gas (exhaust gas) of an internal combustion engine, an apparatus for removing harmful components using a carrier carrying a catalyst is known. That is, a catalyst component is fixed inside a carrier having a large number of micropores formed therethrough and exhaust gas is circulated, and carbon monoxide, unburned combustion components, nitrogen oxides, particulate matter contained in the exhaust gas are contained. (PM). Examples of the type of the carrier include a ceramic molded product and a metal product (metal carrier). Further, the type of the catalyst supported on the carrier is variously selected according to the substance to be purified (see Patent Documents 1 to 3).
排ガスに含まれるPMを捕集して燃焼させる排ガス浄化装置では、PMをそのまま大気に放出すると環境悪化につながるため、排ガス浄化性能を効率的に高める必要がある。
(4) In an exhaust gas purification device that collects and burns PM contained in exhaust gas, if PM is directly released to the atmosphere, it will lead to environmental degradation. Therefore, it is necessary to efficiently improve exhaust gas purification performance.
本件の目的の一つは、上記のような課題に鑑みて創案されたものであり、排ガス浄化性能を効率的に高める排ガス浄化装置を提供することである。
目的 One of the objects of the present invention was created in view of the above-mentioned problems, and it is an object of the present invention to provide an exhaust gas purifying apparatus that efficiently improves exhaust gas purifying performance.
（１）開示の排ガス浄化装置は、入口セル及び出口セルを有するウォールフロー型の担体の隔壁内部に貴金属が担持され、内燃機関の排ガスに含まれる粒子状物質を捕集して燃焼させる排ガス浄化装置である。本装置は、隔壁表面のうち前記入口セルに面する側の上流側に触媒が担持される入口上流部を備える。また、前記隔壁表面のうち前記出口セルに面する側の下流側に触媒が担持される出口下流部を備える。
(1) The disclosed exhaust gas purification apparatus purifies an exhaust gas in which a noble metal is supported inside a partition of a wall flow type carrier having an inlet cell and an outlet cell, and the particulate matter contained in exhaust gas of an internal combustion engine is collected and burned. Device. The present apparatus is provided with an inlet upstream portion in which a catalyst is supported on an upstream side of the partition wall surface facing the inlet cell. In addition, an outlet downstream portion on which a catalyst is supported is provided on a downstream side of the partition wall surface facing the outlet cell.
前記隔壁内部に担持される貴金属の具体例としては、金(Au)，銀(Ag)，白金族元素〔ルテニウム(Ru)，ロジウム(Rh)，パラジウム(Pd)，オスミウム(Os)，イリジウム(Ir)，白金(Pt)〕などが挙げられる。これらの少なくとも一つ以上が、前記隔壁内部に担持される。好ましくは、白金(Pt)よりも触媒性能の高いロジウム(Rh)またはパラジウム(Pd)が前記隔壁内部に担持される。
Specific examples of the noble metal supported inside the partition include gold (Au), silver (Ag), platinum group elements [ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium ( Ir), platinum (Pt)]. At least one of these is carried inside the partition. Preferably, rhodium (Rh) or palladium (Pd) having a higher catalytic performance than platinum (Pt) is supported inside the partition.
前記入口上流部は、前記担体の入口端面から前記入口セルの最奥部よりも手前までの範囲をカバーするように設けられることが好ましい。換言すれば、前記隔壁表面のうち前記入口セルに面する側の下流側には、触媒が担持されない部位が設けられることが好ましい。同様に、前記出口下流部は、前記担体の出口端面から前記出口セルの最奥部よりも手前までの範囲をカバーするように設けられることが好ましい。換言すれば、前記隔壁表面のうち前記出口セルに面する側の上流側には、触媒が担持されない部位が設けられることが好ましい。
It is preferable that the inlet upstream portion is provided so as to cover a range from the inlet end face of the carrier to a position shorter than the innermost portion of the inlet cell. In other words, it is preferable that a portion on which no catalyst is supported is provided on the downstream side of the partition wall surface facing the inlet cell. Similarly, it is preferable that the outlet downstream portion is provided so as to cover a range from the outlet end surface of the carrier to a position closer to the front than the innermost portion of the outlet cell. In other words, it is preferable that a portion on which no catalyst is supported is provided on the upstream side of the partition wall surface facing the outlet cell.
（２）また、前記出口下流部が貴金属を含むことが好ましい。前記出口下流部に担持される貴金属の具体例としては、金(Au)，銀(Ag)，白金族元素〔ルテニウム(Ru)，ロジウム(Rh)，パラジウム(Pd)，オスミウム(Os)，イリジウム(Ir)，白金(Pt)〕などが挙げられる。好ましくは、白金(Pt)よりも触媒性能の高いロジウム(Rh)またはパラジウム(Pd)が用いられる。
（３）前記入口上流部が銀(Ag)または酸化セリウム(CeO2)を含むことが好ましい。好ましくは、銀(Ag)及び酸化セリウム(CeO2)の双方が前記入口上流部に含まれる。 (2) Preferably, the downstream portion of the outlet contains a noble metal. Specific examples of the noble metal supported on the downstream of the outlet include gold (Au), silver (Ag), platinum group elements [ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium. (Ir), platinum (Pt)] and the like. Preferably, rhodium (Rh) or palladium (Pd) having higher catalytic performance than platinum (Pt) is used.
(3) Preferably, the upstream portion of the inlet contains silver (Ag) or cerium oxide (CeO 2 ). Preferably, both silver (Ag) and cerium oxide (CeO 2 ) are included in the inlet upstream.
（３）前記入口上流部が銀(Ag)または酸化セリウム(CeO2)を含むことが好ましい。好ましくは、銀(Ag)及び酸化セリウム(CeO2)の双方が前記入口上流部に含まれる。 (2) Preferably, the downstream portion of the outlet contains a noble metal. Specific examples of the noble metal supported on the downstream of the outlet include gold (Au), silver (Ag), platinum group elements [ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium. (Ir), platinum (Pt)] and the like. Preferably, rhodium (Rh) or palladium (Pd) having higher catalytic performance than platinum (Pt) is used.
(3) Preferably, the upstream portion of the inlet contains silver (Ag) or cerium oxide (CeO 2 ). Preferably, both silver (Ag) and cerium oxide (CeO 2 ) are included in the inlet upstream.
（４）前記入口上流部が希土類元素を含むことが好ましい。ここでいう希土類元素の具体例としては、スカンジウム(Sc)，イットリウム(Y)，ランタノイド〔ランタン(La)，セリウム(Ce)，プラセオジム(Pr)，ネオジム(Nd)，プロメチウム(Pm)，サマリウム(Sm)，ユウロピウム(Eu)，ガドリニウム(Gd)，テルビウム(Tb)，ジスプロシウム(Dy)，ホルミウム(Ho)，エルビウム(Er)，ツリウム(Tm)，イッテルビウム(Yb)，ルテチウム(Lu)〕が挙げられる。これらの少なくとも一つ以上が前記入口上流部に担持されることが好ましい。
(4) Preferably, the upstream portion of the inlet contains a rare earth element. Specific examples of the rare earth element here include scandium (Sc), yttrium (Y), lanthanoid [lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium ( Sm), Europium (Eu), Gadolinium (Gd), Terbium (Tb), Dysprosium (Dy), Holmium (Ho), Erbium (Er), Thulium (Tm), Ytterbium (Yb), Lutetium (Lu)] Can be It is preferable that at least one of these is carried in the inlet upstream part.
（５）前記入口上流部が銀または酸化セリウムと希土類元素とを含む場合には、銀または酸化セリウムが含まれる部位を前記入口セル側に露出させることが好ましい。すなわち、前記入口上流部が銀または酸化セリウムを含む表層と希土類元素を含む基層とを有することが好ましい。
（６）前記隔壁内部が窒素酸化物をトラップするバリウム(Ba)またはカリウム(K)を含むことが好ましい。なお、バリウム(Ba)，カリウム(K)は窒素酸化物(NOx)を一時的に吸着するNOxトラップ触媒として作用する。 (5) When the inlet upstream portion contains silver or cerium oxide and a rare earth element, it is preferable to expose a portion containing silver or cerium oxide to the inlet cell side. That is, it is preferable that the upstream portion of the inlet has a surface layer containing silver or cerium oxide and a base layer containing a rare earth element.
(6) Preferably, the inside of the partition contains barium (Ba) or potassium (K) for trapping nitrogen oxides. Barium (Ba) and potassium (K) act as NOx trap catalysts for temporarily adsorbing nitrogen oxides (NOx).
（６）前記隔壁内部が窒素酸化物をトラップするバリウム(Ba)またはカリウム(K)を含むことが好ましい。なお、バリウム(Ba)，カリウム(K)は窒素酸化物(NOx)を一時的に吸着するNOxトラップ触媒として作用する。 (5) When the inlet upstream portion contains silver or cerium oxide and a rare earth element, it is preferable to expose a portion containing silver or cerium oxide to the inlet cell side. That is, it is preferable that the upstream portion of the inlet has a surface layer containing silver or cerium oxide and a base layer containing a rare earth element.
(6) Preferably, the inside of the partition contains barium (Ba) or potassium (K) for trapping nitrogen oxides. Barium (Ba) and potassium (K) act as NOx trap catalysts for temporarily adsorbing nitrogen oxides (NOx).
（７）前記入口上流部と前記出口下流部とが側面視で上下方向にオーバーラップして配置されることが好ましい。例えば、側面視での前記入口セルの全長LUPに対して前記入口上流部の長さL1を60％とし、前記出口セルの全長LDOWNに対して前記出口下流部の長さL2も60％とする。前記入口上流部の好ましい長さL1の範囲は例えば0.5LUP≦L1<0.75LUPであり、前記出口下流部の好ましい長さL2の範囲は例えば0.5LDOWN≦L2<0.75LDOWNである。
(7) It is preferable that the inlet upstream portion and the outlet downstream portion are arranged so as to overlap in the vertical direction in a side view. For example, the length L 1 of the inlet upstream portion to 60% to the total length L UP of the inlet cells in a side view, also the length L 2 of the outlet downstream portion with respect to the total length L DOWN of the outlet cells 60%. The preferred length range L 1 of the inlet upstream portion is, for example, 0.5L UP ≦ L 1 <0.75L UP , preferred length range of L 2 of the outlet downstream portion, for example 0.5 L DOWN ≦ L 2 <0.75 L DOWN .
（８）開示の排ガス浄化装置は、担体の隔壁内部に貴金属が担持され、内燃機関の排ガスに含まれる粒子状物質を捕集して燃焼させる排ガス浄化装置である。本装置においては、前記粒子状物質の燃焼を促進する燃焼促進触媒が下流側よりも上流側で高密度に担持される。前記燃焼促進触媒の具体例としては、銀(Ag)，酸化セリウム(CeO2)，銀セリア(Ag/CeO2)，錫セリア(Sn/CeO2)，セリアジルコニア（CeO2/ZrO2）などが挙げられる。
(8) The disclosed exhaust gas purifying apparatus is an exhaust gas purifying apparatus in which a noble metal is carried inside a partition of a carrier, and the particulate matter contained in exhaust gas of an internal combustion engine is collected and burned. In the present apparatus, a combustion promoting catalyst for promoting the combustion of the particulate matter is supported at a higher density on the upstream side than on the downstream side. Specific examples of the combustion promoting catalyst include silver (Ag), cerium oxide (CeO 2 ), silver ceria (Ag / CeO 2 ), tin ceria (Sn / CeO 2 ), and ceria zirconia (CeO 2 / ZrO 2 ). Is mentioned.
前記隔壁内部に担持される貴金属の具体例としては、金(Au)，銀(Ag)，白金族元素〔ルテニウム(Ru)，ロジウム(Rh)，パラジウム(Pd)，オスミウム(Os)，イリジウム(Ir)，白金(Pt)〕などが挙げられる。これらの少なくとも一つ以上が、前記隔壁内部に担持される。好ましくは、白金(Pt)よりも触媒性能の高いロジウム(Rh)またはパラジウム(Pd)が前記隔壁内部に担持される。
Specific examples of the noble metal supported inside the partition include gold (Au), silver (Ag), platinum group elements [ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium ( Ir), platinum (Pt)]. At least one of these is carried inside the partition. Preferably, rhodium (Rh) or palladium (Pd) having a higher catalytic performance than platinum (Pt) is supported inside the partition.
（９）前記燃焼促進触媒が前記隔壁内部に担持されることが好ましい。つまり、前記燃焼促進触媒が前記隔壁内部の上流側に高密度で担持されることが好ましい。
（１０）前記担体が入口セル及び出口セルを有するウォールフロー型担体であって、前記燃焼促進触媒が、前記入口セルまでの距離が所定値以下となる範囲内に担持されることが好ましい。例えば、前記隔壁の内部を厚み方向の中央で区画したときに、前記入口セルに近い側に前記燃焼促進触媒を担持させることが考えられる。 (9) Preferably, the combustion promoting catalyst is carried inside the partition. That is, it is preferable that the combustion promoting catalyst is supported at a high density on the upstream side inside the partition wall.
(10) Preferably, the support is a wall flow type support having an inlet cell and an outlet cell, and the combustion promoting catalyst is supported within a range in which a distance to the inlet cell is equal to or less than a predetermined value. For example, when the inside of the partition is partitioned at the center in the thickness direction, it is conceivable to carry the combustion promoting catalyst on the side near the inlet cell.
（１０）前記担体が入口セル及び出口セルを有するウォールフロー型担体であって、前記燃焼促進触媒が、前記入口セルまでの距離が所定値以下となる範囲内に担持されることが好ましい。例えば、前記隔壁の内部を厚み方向の中央で区画したときに、前記入口セルに近い側に前記燃焼促進触媒を担持させることが考えられる。 (9) Preferably, the combustion promoting catalyst is carried inside the partition. That is, it is preferable that the combustion promoting catalyst is supported at a high density on the upstream side inside the partition wall.
(10) Preferably, the support is a wall flow type support having an inlet cell and an outlet cell, and the combustion promoting catalyst is supported within a range in which a distance to the inlet cell is equal to or less than a predetermined value. For example, when the inside of the partition is partitioned at the center in the thickness direction, it is conceivable to carry the combustion promoting catalyst on the side near the inlet cell.
（１１）前記担体の隔壁表面のうち前記入口セルに面する側の上流側に設けられ前記燃焼促進触媒が担持される入口上流部を備えることが好ましい。
（１２）前記担体の隔壁表面のうち前記出口セルに面する側かつ下流側に設けられ貴金属が担持される出口下流部を備えることが好ましい。
（１３）前記入口上流部と前記出口下流部とが側面視で上下方向にオーバーラップして配置されることが好ましい。 (11) It is preferable to include an inlet upstream portion provided on the upstream side of the partition wall surface of the carrier facing the inlet cell and supporting the combustion promoting catalyst.
(12) It is preferable to provide an outlet downstream portion provided on the side facing the outlet cell and on the downstream side of the partition wall surface of the carrier and supporting a noble metal.
(13) It is preferable that the inlet upstream portion and the outlet downstream portion are arranged so as to overlap vertically in a side view.
（１２）前記担体の隔壁表面のうち前記出口セルに面する側かつ下流側に設けられ貴金属が担持される出口下流部を備えることが好ましい。
（１３）前記入口上流部と前記出口下流部とが側面視で上下方向にオーバーラップして配置されることが好ましい。 (11) It is preferable to include an inlet upstream portion provided on the upstream side of the partition wall surface of the carrier facing the inlet cell and supporting the combustion promoting catalyst.
(12) It is preferable to provide an outlet downstream portion provided on the side facing the outlet cell and on the downstream side of the partition wall surface of the carrier and supporting a noble metal.
(13) It is preferable that the inlet upstream portion and the outlet downstream portion are arranged so as to overlap vertically in a side view.
（１４）前記隔壁内部に窒素酸化物をトラップする窒素酸化物トラップ触媒を含むことが好ましい。前記窒素酸化物トラップ触媒の具体例としては、アルカリ金属やアルカリ土類金属が挙げられる。例えば、バリウム(Ba)，カリウム(K)，ルビジウム(Rb)，ストロンチウム(Sr)，セシウム（Cs），フランシウム(Fr)，ラジウム(Ra)などである。
(14) It is preferable that a nitrogen oxide trap catalyst for trapping nitrogen oxides is included in the partition. Specific examples of the nitrogen oxide trap catalyst include alkali metals and alkaline earth metals. For example, barium (Ba), potassium (K), rubidium (Rb), strontium (Sr), cesium (Cs), francium (Fr), radium (Ra), and the like.
（１５）前記窒素酸化物トラップ触媒が上流側よりも下流側で高密度に担持されることが好ましい。
（１６）前記窒素酸化物トラップ触媒がバリウム及びカリウムを含み、前記窒素酸化物トラップ触媒の全体に対する前記カリウムの含有割合が上流側よりも下流側で高く設定されることが好ましい。 (15) It is preferable that the nitrogen oxide trap catalyst is supported at a higher density on the downstream side than on the upstream side.
(16) It is preferable that the nitrogen oxide trap catalyst contains barium and potassium, and the content ratio of potassium relative to the entire nitrogen oxide trap catalyst is set higher on the downstream side than on the upstream side.
（１６）前記窒素酸化物トラップ触媒がバリウム及びカリウムを含み、前記窒素酸化物トラップ触媒の全体に対する前記カリウムの含有割合が上流側よりも下流側で高く設定されることが好ましい。 (15) It is preferable that the nitrogen oxide trap catalyst is supported at a higher density on the downstream side than on the upstream side.
(16) It is preferable that the nitrogen oxide trap catalyst contains barium and potassium, and the content ratio of potassium relative to the entire nitrogen oxide trap catalyst is set higher on the downstream side than on the upstream side.
排ガス浄化性能を効率的に高めることができる。
The exhaust gas purification performance can be improved efficiently.
［１．第一実施形態］
［１－１．構成］
以下、図面を参照して、第一の実施形態としての排ガス浄化装置について説明する。図１に示すように、本件の排ガス浄化装置３は、エンジン１（内燃機関）を搭載した車両１０に適用される。エンジン１の種類はディーゼルエンジンであってもよいし、ガソリンエンジンであってもよい。なお、本件の排ガス浄化装置３は、リーンバーン運転が可能なガソリンエンジンに好適である。 [1. First Embodiment]
[1-1. Constitution]
Hereinafter, an exhaust gas purifying apparatus as a first embodiment will be described with reference to the drawings. As shown in FIG. 1, the exhaustgas purification device 3 of the present application is applied to a vehicle 10 equipped with an engine 1 (internal combustion engine). The type of the engine 1 may be a diesel engine or a gasoline engine. In addition, the exhaust gas purifying apparatus 3 of the present case is suitable for a gasoline engine capable of lean burn operation.
［１－１．構成］
以下、図面を参照して、第一の実施形態としての排ガス浄化装置について説明する。図１に示すように、本件の排ガス浄化装置３は、エンジン１（内燃機関）を搭載した車両１０に適用される。エンジン１の種類はディーゼルエンジンであってもよいし、ガソリンエンジンであってもよい。なお、本件の排ガス浄化装置３は、リーンバーン運転が可能なガソリンエンジンに好適である。 [1. First Embodiment]
[1-1. Constitution]
Hereinafter, an exhaust gas purifying apparatus as a first embodiment will be described with reference to the drawings. As shown in FIG. 1, the exhaust
排ガス浄化装置３は、エンジン１の排気通路２に介装される。排ガス浄化装置３は、排ガスに含まれる各種有害成分を効率よく浄化するための触媒装置であり、三元触媒としての機能と、NOx吸蔵還元触媒としての機能と、PM除去フィルターとしての機能とを併せ持つ。排ガス浄化装置３の配設位置は、例えば図１中に示すように、エンジン１に近接した位置（エキゾーストマニホールドの直下流側や過給機の直下流側など）に設定してもよいし、エンジン１から離れた位置に設定してもよい。また、排ガス浄化装置３の上流側や下流側に三元触媒コンバーターを別設し、排ガス浄化性能を向上させてもよい。
The exhaust gas purification device 3 is interposed in the exhaust passage 2 of the engine 1. The exhaust gas purification device 3 is a catalyst device for efficiently purifying various harmful components contained in exhaust gas, and has a function as a three-way catalyst, a function as a NOx storage reduction catalyst, and a function as a PM removal filter. Have both. The disposition position of the exhaust gas purifying device 3 may be set at a position close to the engine 1 (directly downstream of the exhaust manifold or immediately downstream of the supercharger, for example) as shown in FIG. It may be set at a position away from the engine 1. Further, a three-way catalytic converter may be separately provided upstream or downstream of the exhaust gas purifying device 3 to improve the exhaust gas purifying performance.
排ガス浄化装置３の内部には、排ガスが通過しうる多数の流路が形成された多孔質体が設けられる。多孔質体とは、多孔質の担体７に触媒９を担持させたものであり、円筒状や楕円筒状，直方体状に形成される。担体７の材料は、炭化ケイ素やコーディエライト（コージライト）などのセラミックスであってもよいし金属であってもよい。担体７の空孔率は高いほど好ましい。本実施形態の担体７は空孔率が50[％]を超え、かつ直径が1[μm]以上の細孔についての細孔容積が0.2[mL/g]を超えるものとする。
多孔 Inside the exhaust gas purifying device 3, there is provided a porous body in which a number of flow paths through which the exhaust gas can pass are formed. The porous body is obtained by supporting the catalyst 9 on a porous carrier 7 and is formed in a cylindrical shape, an elliptic cylindrical shape, or a rectangular parallelepiped shape. The material of the carrier 7 may be a ceramic such as silicon carbide or cordierite (cordierite) or a metal. The porosity of the carrier 7 is preferably as high as possible. The carrier 7 of the present embodiment has a porosity exceeding 50 [%] and a pore volume of pores having a diameter of 1 [μm] or more exceeding 0.2 [mL / g].
触媒９を担体７に担持させるための母材例としては、酸化アルミニウム（アルミナ，Al2O3）や酸化セリウム（セリア，CeO2）や酸化ジルコニウム（ジルコニア，ZrO2）などが挙げられる。なお、還元環境下で酸素を吸蔵する酸素吸蔵材料を母材に含ませてもよい。酸素吸蔵材料の例としては、セリア・ジルコニア複合固溶体（CeO2-ZrO2系物質）や希土類オキシ硫酸塩（Ln2O2SO4）などが挙げられる。
Examples of a base material for supporting the catalyst 9 on the carrier 7 include aluminum oxide (alumina, Al 2 O 3 ), cerium oxide (ceria, CeO 2 ), and zirconium oxide (zirconia, ZrO 2 ). Note that an oxygen storage material that stores oxygen in a reducing environment may be included in the base material. Examples of the oxygen storage material include a ceria-zirconia composite solid solution (CeO 2 -ZrO 2 -based substance) and rare earth oxysulfate (Ln 2 O 2 SO 4 ).
排ガス浄化装置３に内装される多孔質体の構造は、図２に示すようなウォールフロー型である。担体７の内部は、排ガスの流通方向に沿って複数のセル（小部屋状の通路）に分割され、各セルは多孔質の隔壁６（リブ）によって区画される。また、各セルは入口側か出口側のいずれかの端が目封じ８によって閉塞される。出口側の端部が閉塞されたセルは入口セル４と呼ばれ、入口側の端部が閉塞されたセルは出口セル５と呼ばれる。
構造 The structure of the porous body provided in the exhaust gas purification device 3 is a wall flow type as shown in FIG. The inside of the carrier 7 is divided into a plurality of cells (small chamber-like passages) along the flow direction of the exhaust gas, and each cell is partitioned by a porous partition wall 6 (rib). Further, each cell is closed at one end on the inlet side or the outlet side by a plug 8. The cell whose outlet end is closed is called an inlet cell 4, and the cell whose inlet end is closed is called an outlet cell 5.
それぞれの入口セル４は、少なくとも一つ以上の出口セル５に隣接するように配置され、好ましくは多数の出口セル５に隣接するように配置される。これにより、担体７の入口端面１１から流入した排ガスは、まず入口セル４へと進入し、隔壁６の中を通過したのちに出口セル５へと進入して、担体７の出口端面１２から流出する。つまり、すべての排ガスが隔壁６の内部を通過することになり、PM捕集効率が向上する。
Each inlet cell 4 is arranged adjacent to at least one or more outlet cells 5, and is preferably arranged adjacent to a number of outlet cells 5. As a result, the exhaust gas flowing from the inlet end face 11 of the carrier 7 first enters the inlet cell 4, passes through the partition 6, then enters the outlet cell 5, and flows out of the outlet end face 12 of the carrier 7. I do. That is, all the exhaust gas passes through the inside of the partition 6, and the PM collection efficiency is improved.
担体７には、その部位に応じた種類の触媒９が担持される。例えば、隔壁６の内部と表面とで異なる触媒９が担持される。また、隔壁６の表面において、入口セル４側と出口セル５側とで異なる触媒９が担持される。以下、隔壁６の内部のことを「隔壁内部１３」と呼ぶ。隔壁内部１３には、貴金属触媒が担持される。貴金属の具体例としては、白金族元素〔白金(Pt)，パラジウム(Pd)，ルテニウム(Ru)，ロジウム(Rh)，オスミウム(Os)，イリジウム(Ir)〕や金(Au)，銀(Ag)などが挙げられる。
The catalyst 9 of a type corresponding to the site is supported on the carrier 7. For example, different catalysts 9 are carried between the inside and the surface of the partition 6. Further, on the surface of the partition wall 6, different catalysts 9 are carried on the inlet cell 4 side and the outlet cell 5 side. Hereinafter, the inside of the partition 6 is referred to as "partition interior 13". A noble metal catalyst is supported in the partition interior 13. Specific examples of the noble metal include platinum group elements [platinum (Pt), palladium (Pd), ruthenium (Ru), rhodium (Rh), osmium (Os), iridium (Ir)], gold (Au), silver (Ag) ).
好ましくは、白金よりも触媒性能の高いロジウムやパラジウムが用いられる。図５に示すように、ロジウムやパラジウムは白金よりも担持量あたりの触媒活性（全炭化水素に対する変換効率）が高い。したがって、ロジウムやパラジウムを用いることで、効率的に排ガス浄化性能を高めることができる。なお、ロジウムを用いる場合にはその担持密度を1.0[g/L]程度とする。
Preferably, rhodium or palladium having higher catalytic performance than platinum is used. As shown in FIG. 5, rhodium and palladium have a higher catalytic activity per supported amount (conversion efficiency with respect to total hydrocarbons) than platinum. Therefore, by using rhodium or palladium, the exhaust gas purification performance can be efficiently increased. When rhodium is used, its carrying density is about 1.0 [g / L].
前述の通り、隔壁６の表面には入口セル４側と出口セル５側とで異なる触媒層が形成される。図２～図４に示すように、担体７の隔壁表面のうち、入口セル４に面する側の上流側には入口上流部１４が設けられる。入口上流部１４は、入口端面１１から入口セル４の最奥部よりも手前までの範囲をカバーするように設けられる。つまり、入口セル４に面する隔壁表面のうち、入口上流部１４よりも下流側には触媒が担持されない。側面視での入口上流部１４の長さL1は、入口セルの全長LUPに対して少なくとも「0<L1<LUP」の関係を満たし、好ましくは「0.5LUP≦L1<0.75LUP」の関係を満たすように設定される。
As described above, different catalyst layers are formed on the surface of the partition wall 6 on the inlet cell 4 side and the outlet cell 5 side. As shown in FIGS. 2 to 4, an inlet upstream portion 14 is provided on the upstream side of the partition wall surface of the carrier 7 facing the inlet cell 4. The inlet upstream portion 14 is provided so as to cover a range from the inlet end face 11 to a position closer to the front than the innermost portion of the inlet cell 4. That is, the catalyst is not carried on the downstream side of the inlet upstream portion 14 in the partition wall surface facing the inlet cell 4. The length L 1 of the inlet upstream portion 14 in side view satisfies the relationship of at least "0 <L 1 <L UP" to the total length L UP inlet cells, preferably "0.5 L UP ≦ L 1 <0.75 L UP ”.
また、担体７の隔壁表面のうち、出口セル５に面する側の下流側には出口下流部１５が設けられる。出口下流部１５は、出口端面１２から出口セル５の最奥部よりも手前までの範囲をカバーするように設けられる。つまり、出口セル５に面する隔壁表面のうち、出口下流部１５よりも上流側には触媒が担持されない。側面視での出口下流部１５の長さL2は、出口セルの全長LDOWNに対して少なくとも「0<L2<LDOWN」の関係を満たし、好ましくは「0.5LDOWN≦L2<0.75LDOWN」の関係を満たすように設定される。
An outlet downstream portion 15 is provided on the downstream side of the partition wall surface of the carrier 7 facing the outlet cell 5. The outlet downstream part 15 is provided so as to cover a range from the outlet end face 12 to a position closer to the front than the innermost part of the outlet cell 5. That is, the catalyst is not carried on the upstream side of the outlet downstream portion 15 in the partition wall surface facing the outlet cell 5. The length L 2 of the outlet downstream section 15 in side view satisfies the relationship of at least "0 <L 2 <L DOWN" to the total length L DOWN outlet cells, preferably "0.5 L DOWN ≦ L 2 <0.75 L DOWN ”.
より好ましくは、図２～図４に示すように、入口上流部１４と出口下流部１５とが側面視で上下方向にオーバーラップして配置される。例えば、側面視での入口セル４の全長LUPに対して、入口上流部１４の長さL1を60％とする。また、出口セル５の全長LDOWNに対して、出口下流部１５の長さL2も60％とする。この場合、入口上流部１４の下流端部と出口下流部１５の上流端部とが図２～図４中で上下方向にオーバーラップした状態となる。これにより、入口上流部１４や出口下流部１５の近傍を通過せずに流出する排ガスの量が減少し、PM捕集効率や排ガス浄化効率が向上する。
More preferably, as shown in FIGS. 2 to 4, the inlet upstream portion 14 and the outlet downstream portion 15 are arranged so as to overlap in the vertical direction in a side view. For example, with respect to the total length L UP inlet cells 4 in side view, the length L 1 of the inlet upstream section 14 and 60%. Further, the length L 2 of the outlet downstream portion 15 is also set to 60% of the total length L DOWN of the outlet cell 5. In this case, the downstream end of the inlet upstream section 14 and the upstream end of the outlet downstream section 15 are vertically overlapped in FIGS. 2 to 4. As a result, the amount of exhaust gas flowing out without passing near the inlet upstream portion 14 and the outlet downstream portion 15 is reduced, and the PM collection efficiency and the exhaust gas purification efficiency are improved.
入口上流部１４には、銀(Ag)または酸化セリウム(CeO2)または希土類元素（Rare-Earth Elements，REE）を担持させることが好ましい。銀や酸化セリウムはPMの燃焼促進材として機能し、隔壁内部１３に担持される貴金属よりも低温でPMを燃焼させうる。一方、希土類元素は、P/Znトラップ（リン及び亜鉛トラップ）として機能し、排ガス中に含まれるリンや亜鉛による被毒を抑制する。なお、銀を用いる場合にはその担持密度を2.0[g/L]程度とする。
It is preferable that silver (Ag), cerium oxide (CeO 2 ), or a rare earth element (Rare-Earth Elements, REE) is supported on the inlet upstream portion 14. Silver or cerium oxide functions as a PM promoter, and can burn PM at a lower temperature than the noble metal supported in the partition interior 13. On the other hand, rare earth elements function as P / Zn traps (phosphorus and zinc traps) and suppress poisoning by phosphorus and zinc contained in exhaust gas. When silver is used, its carrying density is about 2.0 [g / L].
前者（銀，酸化セリウム）と後者（希土類）とをともに入口上流部１４に担持させる場合には、銀，酸化セリウムが含まれる部位を入口セル４側に露出させることが好ましい。例えば図４に示すように、希土類元素を含む部位を基層１６とし、銀，酸化セリウムを含む部位を表層１７とすることが好ましい。この場合、希土類元素を含む基層１６をウォッシュコート法で形成した後に、銀，酸化セリウムを含む表層１７を再びウォッシュコート法で形成すればよい。入口セル４側に銀，酸化セリウムを露出させることで、PMの燃焼性が向上する。なお、前者（銀，酸化セリウム）と後者（希土類）とのいずれか一方を入口上流部１４に担持させる場合には、図３に示すように、単一層を形成すればよい。
In the case where both the former (silver and cerium oxide) and the latter (rare earth) are supported on the inlet upstream portion 14, it is preferable to expose the portion containing silver and cerium oxide to the inlet cell 4 side. For example, as shown in FIG. 4, it is preferable that a portion containing a rare earth element be the base layer 16 and a portion containing silver and cerium oxide be the surface layer 17. In this case, after forming the base layer 16 containing the rare earth element by the wash coat method, the surface layer 17 containing silver and cerium oxide may be formed again by the wash coat method. By exposing silver and cerium oxide to the inlet cell 4 side, PM combustibility is improved. When one of the former (silver, cerium oxide) and the latter (rare earth) is to be carried by the inlet upstream portion 14, a single layer may be formed as shown in FIG.
ここでいう希土類元素の具体例としては、スカンジウム(Sc)，イットリウム(Y)，ランタノイド〔ランタン(La)，セリウム(Ce)，プラセオジム(Pr)，ネオジム(Nd)，プロメチウム(Pm)，サマリウム(Sm)，ユウロピウム(Eu)，ガドリニウム(Gd)，テルビウム(Tb)，ジスプロシウム(Dy)，ホルミウム(Ho)，エルビウム(Er)，ツリウム(Tm)，イッテルビウム(Yb)，ルテチウム(Lu)〕が挙げられる。これらの少なくとも一つ以上を入口上流部１４に担持させることで、P/Znトラップ性能が向上する。
Specific examples of the rare earth element here include scandium (Sc), yttrium (Y), lanthanoid [lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium ( Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu)] Can be By supporting at least one of these at the inlet upstream portion 14, the P / Zn trap performance is improved.
出口下流部１５には、貴金属を担持させることが好ましい。出口下流部１５に担持される貴金属の具体例としては、白金族元素〔白金，パラジウム，ルテニウム，ロジウム，オスミウム，イリジウム〕，金，銀などが挙げられる。ここで担持される貴金属の種類は、隔壁内部１３に担持されるものと同一であってもよいし、相違してもよい。好ましくは、ロジウムまたはパラジウムが用いられる。なお、ロジウムを用いる場合にはその担持密度を0.4[g/L]程度とする。
貴 It is preferable that a noble metal is carried in the outlet downstream portion 15. Specific examples of the noble metal supported on the outlet downstream portion 15 include platinum group elements [platinum, palladium, ruthenium, rhodium, osmium, iridium], gold, silver and the like. The type of the noble metal carried here may be the same as or different from that carried on the inside 13 of the partition wall. Preferably, rhodium or palladium is used. When rhodium is used, its loading density is about 0.4 [g / L].
なお、隔壁内部１３には貴金属だけでなくバリウム(Ba)またはカリウム(K)を含ませてもよい。バリウム，カリウムはNOxを一時的に吸着するNOxトラップとして作用する。図６に示すように、カリウムはバリウムよりも高温でのNOx浄化に適しており、燃焼温度の高いガソリンエンジンでの排ガス浄化に適している。また、カリウムはバリウムよりもNO2のトラップ性能が高く、NOx浄化効率が高い。一方、カリウムは熱的に不安定であり、担持位置から落下，飛散することがある。この場合、飛散したカリウムが他の触媒や貴金属の触媒作用（三元活性，特にTHC浄化性能）を阻害しうる。したがって、カリウムだけでなくバリウムを併用することが好ましい。
The partition interior 13 may contain not only a noble metal but also barium (Ba) or potassium (K). Barium and potassium act as a NOx trap that temporarily adsorbs NOx. As shown in FIG. 6, potassium is suitable for NOx purification at a higher temperature than barium, and is suitable for exhaust gas purification in a gasoline engine having a high combustion temperature. Further, potassium has higher NO 2 trapping performance and higher NOx purification efficiency than barium. On the other hand, potassium is thermally unstable and may fall or scatter from the loading position. In this case, the scattered potassium may hinder the catalytic action (ternary activity, especially THC purification performance) of another catalyst or a noble metal. Therefore, it is preferable to use not only potassium but also barium.
触媒９の種類と担持位置との組み合わせを、以下の表１，表２に例示する。ここでは、20種類の実施例（No.1～No.20）を示す。すべての実施例において、隔壁内部１３に貴金属が含まれている。表中の「Pd/Rh」はパラジウムまたはロジウムを含むことを意味し、「Pd/Rh-Ba/K」はさらにバリウムまたはカリウムが添加されていることを意味する。また、表中の「Ag/CeO2」は銀または酸化セリウムを含むことを意味し、「REE」は希土類元素を含むことを意味する。
Combinations of the type of the catalyst 9 and the supporting position are shown in Tables 1 and 2 below. Here, twenty types of examples (No. 1 to No. 20) are shown. In all the embodiments, the noble metal is contained in the partition interior 13. "Pd / Rh" in the table means that palladium or rhodium is contained, and "Pd / Rh-Ba / K" means that barium or potassium is further added. “Ag / CeO 2 ” in the table means that silver or cerium oxide is contained, and “REE” means that rare earth elements are contained.
表中の空欄は、触媒非担持としてもよいし、何らかの触媒（例えば白金，遷移金属硫酸塩，アルカリ金属硫酸塩など）を担持させてもよい。少なくともNo.1，No.6，No.11，No.16の入口上流部１４については、何らかの触媒が担持されているものとする。同様に、No.1～No.10の出口下流部１５についても、何らかの触媒が担持されているものとする。また、入口上流部１４に銀及び酸化セリウムと希土類元素とがともに含まれないものについては、二層構造にする（基層１６及び表層１７を形成する）必要はない。
空 A blank column in the table may be a non-supported catalyst or a certain catalyst (eg, platinum, transition metal sulfate, alkali metal sulfate, etc.). It is assumed that at least the inlet upstream portions 14 of No. 1, No. 6, No. 11, and No. 16 carry some catalyst. Similarly, it is also assumed that some catalyst is carried in the outlet downstream portions 15 of No. 1 to No. 10. If the inlet upstream portion 14 does not contain both silver and cerium oxide and a rare earth element, it is not necessary to form a two-layer structure (forming the base layer 16 and the surface layer 17).
［１－２．作用・効果］
排ガスに含まれるPMを捕集して燃焼させる排ガス浄化装置では、気孔率（空孔率）を低下させることでPMの捕集効率が向上しうる。しかしながら、PMが捕集された後の圧力損失が大きくなり、エンジン性能に悪影響を与えうる。反対に、気孔率を上昇させれば圧力損失の影響が小さくなるものの、PMの捕集効率が低下する。したがって、PMの捕集効率を高めつつ圧力損失を減少させることが難しいという課題がある。 [1-2. Action / Effect]
In an exhaust gas purifying device that collects and burns PM contained in exhaust gas, PM collection efficiency can be improved by reducing porosity (porosity). However, the pressure loss after the PM is trapped increases, which can adversely affect engine performance. Conversely, if the porosity is increased, the effect of pressure loss is reduced, but the PM collection efficiency is reduced. Therefore, there is a problem that it is difficult to reduce the pressure loss while increasing the PM collection efficiency.
排ガスに含まれるPMを捕集して燃焼させる排ガス浄化装置では、気孔率（空孔率）を低下させることでPMの捕集効率が向上しうる。しかしながら、PMが捕集された後の圧力損失が大きくなり、エンジン性能に悪影響を与えうる。反対に、気孔率を上昇させれば圧力損失の影響が小さくなるものの、PMの捕集効率が低下する。したがって、PMの捕集効率を高めつつ圧力損失を減少させることが難しいという課題がある。 [1-2. Action / Effect]
In an exhaust gas purifying device that collects and burns PM contained in exhaust gas, PM collection efficiency can be improved by reducing porosity (porosity). However, the pressure loss after the PM is trapped increases, which can adversely affect engine performance. Conversely, if the porosity is increased, the effect of pressure loss is reduced, but the PM collection efficiency is reduced. Therefore, there is a problem that it is difficult to reduce the pressure loss while increasing the PM collection efficiency.
このような課題に対し、入口上流部を入口セル側の上流側に設け、出口下流部を出口セル側の下流側に設けることで、排気通路の圧損を低減させることができる。また、PMの捕集効率を向上させつつ圧力損失を減少させることができ、排ガス浄化性能を効率的に高めることができる。具体的にいえば、上記の排ガス浄化装置は、以下のような種々の作用，効果を奏する。
に 対 し In order to solve such a problem, the pressure loss of the exhaust passage can be reduced by providing the inlet upstream portion on the upstream side on the inlet cell side and providing the outlet downstream portion on the downstream side on the outlet cell side. Further, the pressure loss can be reduced while improving the PM collection efficiency, and the exhaust gas purification performance can be efficiently increased. More specifically, the exhaust gas purifying apparatus described above has various functions and effects as described below.
図７(A)～(C)は、入口上流部１４の長さL1を入口セル４の全長LUPの半分（50％）に固定し、出口下流部１５の長さL2をゼロから出口セル５の全長LDOWNまで（0％から100％まで）変化させたときに、圧力損失，排ガスの浄化性能，PM捕集効率のそれぞれがどのように変化するかを示すグラフである。
FIGS. 7A to 7C show that the length L 1 of the inlet upstream portion 14 is fixed to half (50%) of the total length L UP of the inlet cell 4 and the length L 2 of the outlet downstream portion 15 is reduced from zero. 10 is a graph showing how the pressure loss, the exhaust gas purification performance, and the PM collection efficiency change when the total length L DOWN of the outlet cell 5 is changed (from 0% to 100%).
圧力損失は、出口下流部１５の長さL2を全長LDOWNの7～8割以下にすることで小さな値に抑えることが可能である。また、浄化性能及びPM捕集効率は、出口下流部１５の長さL2を全長LDOWNの半分以上にすることで急激に上昇する。したがって、出口下流部１５の好ましい長さL2の範囲は0.5LDOWN≦L2<0.75LDOWNと考えられる。なお、図７(A)～(C)中の破線は、隔壁内部１３に担持される貴金属の担持量を増加させた場合の圧力損失，排ガスの浄化性能，PM捕集効率を示す。このように、出口下流部１５が出口セル５の全長LDOWNにわたる広範囲に形成されない場合であっても、隔壁内部１３の貴金属担持量を調節することで良好な排ガス浄化性能が維持されうる。
The pressure loss can be suppressed to a small value by the length L 2 of the outlet downstream section 15 below 7-8% of the total length L DOWN. Furthermore, purification performance and PM trapping efficiency is drastically increased by the length L 2 of the outlet downstream section 15 in more than half of the total length L DOWN. Thus, the preferred length range L 2 of the outlet downstream section 15 is considered to 0.5L DOWN ≦ L 2 <0.75L DOWN . The broken lines in FIGS. 7A to 7C show the pressure loss, the exhaust gas purification performance, and the PM collection efficiency when the amount of the noble metal supported on the inside 13 of the partition wall is increased. As described above, even when the outlet downstream portion 15 is not formed in a wide range over the entire length L DOWN of the outlet cell 5, good exhaust gas purification performance can be maintained by adjusting the amount of noble metal carried in the partition interior 13.
図８(A)～(C)は、出口下流部１５の長さL2を出口セル５の全長LDOWNの半分（50％）に固定し、入口上流部１４の長さL1をゼロから入口セル４の全長LUPまで（0％から100％まで）変化させたときに、圧力損失，排ガスの浄化性能，PM捕集効率のそれぞれがどのように変化するかを示すグラフである。入口上流部１４の長さL1を全長LDOWNの7～8割以下にすることで圧力損失を小さく抑えることが可能である。また、浄化性能及びPM捕集効率は、入口上流部１４の長さL1を全長LUPの半分以上にすることで急激に上昇する。したがって、入口上流部１４の好ましい長さL1の範囲は0.5LUP≦L1<0.75LUPと考えられる。
FIGS. 8A to 8C show that the length L 2 of the outlet downstream portion 15 is fixed to half (50%) of the total length L DOWN of the outlet cell 5 and the length L 1 of the inlet upstream portion 14 is changed from zero. 6 is a graph showing how the pressure loss, the exhaust gas purification performance, and the PM collection efficiency change when the total length L UP of the inlet cell 4 is changed (from 0% to 100%). It is possible to suppress the pressure loss by the length L 1 of the inlet upstream section 14 below 7-8% of the total length L DOWN. Furthermore, purification performance and PM trapping efficiency is rapidly increased by the length L 1 of the inlet upstream section 14 to more than half of the total length L UP. Thus, the preferred length range L 1 of the inlet upstream section 14 is considered to 0.5L UP ≦ L 1 <0.75L UP .
（１）入口上流部１４を隔壁６の表面のうち入口セル４側の上流側に設け、出口下流部１５を出口セル５側の下流側に設けることで、排気通路２の圧力損失を減少させることができる。また、PMの捕集効率を向上させつつ圧力損失を減少させることができ、排ガス浄化性能を効率的に高めることができる。なお、入口セル４に面する隔壁表面のうち、入口上流部１４よりも下流側には触媒が担持されない。同様に、出口セル５に面する隔壁表面のうち、出口下流部１５よりも上流側には触媒が担持されない。これらの「触媒非担持部」は、排ガスの流通抵抗が小さく圧力損失の小さい流路として機能する。したがって、簡素な構成で圧力損失を減少させることができる。
(1) The pressure loss of the exhaust passage 2 is reduced by providing the inlet upstream section 14 on the upstream side of the inlet cell 4 side of the surface of the partition wall 6 and providing the outlet downstream section 15 on the downstream side of the outlet cell 5 side. be able to. Further, the pressure loss can be reduced while improving the PM collection efficiency, and the exhaust gas purification performance can be efficiently increased. Note that, on the partition wall surface facing the inlet cell 4, no catalyst is supported downstream of the inlet upstream portion 14. Similarly, the catalyst is not carried on the upstream side of the outlet downstream portion 15 in the partition wall surface facing the outlet cell 5. These “catalyst non-supporting portions” function as flow paths having a small exhaust gas flow resistance and a small pressure loss. Therefore, pressure loss can be reduced with a simple configuration.
（２）表２のNo.11～20に示すように、出口下流部１５に貴金属触媒を含ませることで、出口セル５側でのNOx還元効率を高めることができる。これにより、排ガス浄化装置３からのNOxのスリップ量を減少させることができ、排ガス浄化性能を効率的に高めることができる。
（３）表１～表２のNo.2，4，5，7，9，10，12，14，15，17，19，20に示すように、入口上流部１４に銀または酸化セリウムを含ませることで、PMの燃焼を促進することができ、隔壁内部１３よりも低温な状態でPMを燃焼させることができる。これにより、従来よりも短時間で迅速に担体７を再生させることが可能となり、排ガス浄化性能を効率的に高めることができる。また、PMの堆積による圧損上昇を防止することができる。 (2) As shown in Nos. 11 to 20 of Table 2, the NOx reduction efficiency at theoutlet cell 5 side can be increased by including the noble metal catalyst in the outlet downstream portion 15. As a result, the amount of slip of NOx from the exhaust gas purification device 3 can be reduced, and the exhaust gas purification performance can be efficiently increased.
(3) As shown in Nos. 2, 4, 5, 7, 9, 10, 12, 14, 15, 17, 19, and 20 in Tables 1 and 2, silver or cerium oxide is contained in the inletupstream section 14. By doing so, the combustion of PM can be promoted, and the PM can be burned at a lower temperature than the inside 13 of the partition wall. This makes it possible to regenerate the carrier 7 more quickly and in a shorter time than before, and it is possible to efficiently improve exhaust gas purification performance. In addition, an increase in pressure loss due to deposition of PM can be prevented.
（３）表１～表２のNo.2，4，5，7，9，10，12，14，15，17，19，20に示すように、入口上流部１４に銀または酸化セリウムを含ませることで、PMの燃焼を促進することができ、隔壁内部１３よりも低温な状態でPMを燃焼させることができる。これにより、従来よりも短時間で迅速に担体７を再生させることが可能となり、排ガス浄化性能を効率的に高めることができる。また、PMの堆積による圧損上昇を防止することができる。 (2) As shown in Nos. 11 to 20 of Table 2, the NOx reduction efficiency at the
(3) As shown in Nos. 2, 4, 5, 7, 9, 10, 12, 14, 15, 17, 19, and 20 in Tables 1 and 2, silver or cerium oxide is contained in the inlet
（４）表１～表２のNo.3～5，8～10，13～15，18～20に示すように、入口上流部１４に希土類元素を含ませることで、燃料やエンジンオイルに含まれるリン成分や亜鉛成分を希土類元素に吸着させることができる。これにより、耐被毒性を向上させることができ、排ガス浄化性能を効率的に高めることができる。
（５）表１～表２のNo.5，10，15，20に示すように、希土類元素を含む部位を基層１６とし、銀，酸化セリウムを含む部位を表層１７とすることで、耐被毒性を向上させつつPMの燃焼性を効率的に向上させることができる。 (4) As shown in Nos. 3 to 5, 8 to 10, 13 to 15, and 18 to 20 in Tables 1 and 2, by including a rare earth element in the inletupstream section 14, it is contained in fuel and engine oil. Phosphorus component and zinc component can be adsorbed to the rare earth element. Thereby, the poisoning resistance can be improved, and the exhaust gas purification performance can be efficiently increased.
(5) As shown in Nos. 5, 10, 15, and 20 in Tables 1 and 2, the portion containing the rare earth element is used as thebase layer 16 and the portion containing silver and cerium oxide is used as the surface layer 17, so that the coating resistance can be improved. PM flammability can be efficiently improved while improving toxicity.
（５）表１～表２のNo.5，10，15，20に示すように、希土類元素を含む部位を基層１６とし、銀，酸化セリウムを含む部位を表層１７とすることで、耐被毒性を向上させつつPMの燃焼性を効率的に向上させることができる。 (4) As shown in Nos. 3 to 5, 8 to 10, 13 to 15, and 18 to 20 in Tables 1 and 2, by including a rare earth element in the inlet
(5) As shown in Nos. 5, 10, 15, and 20 in Tables 1 and 2, the portion containing the rare earth element is used as the
（６）表１～表２のNo.6～10，16～20に示すように、隔壁内部１３にバリウム，カリウムを含ませることで、隔壁内部１３のNOx吸蔵量を増加させることができる。また、隔壁内部１３には貴金属も含まれているため、バリウム，カリウムに吸蔵されたNOxをその場で還元することが容易であり、NOx浄化効率を高めることができる。
(6) As shown in Nos. 6 to 10 and 16 to 20 in Tables 1 and 2, by including barium and potassium in the inside 13 of the partition, the NOx storage amount in the inside 13 of the partition can be increased. In addition, since the noble metal is also contained in the partition interior 13, NOx stored in barium and potassium can be easily reduced in situ, and the NOx purification efficiency can be increased.
（７）図２～図４に示すように、入口上流部１４と出口下流部１５とを側面視で上下方向にオーバーラップさせることで、PM捕集効率や排ガス浄化効率を高めることができる。なお、入口上流部１４の長さL1を0.5LUP≦L1<0.75LUPの範囲内で設定するとともに、出口下流部１５の長さL2を0.5LDOWN≦L2<0.75LDOWNの範囲内で設定すれば、図７～図８に示すように、圧力損失を過度に上昇させることなく浄化性能とPM捕集効率とを高い水準に維持することができる。
(7) As shown in FIGS. 2 to 4, the PM upstream efficiency and the exhaust gas purification efficiency can be increased by vertically overlapping the inlet upstream section 14 and the outlet downstream section 15 in a side view. Incidentally, the length L 1 of the inlet upstream section 14 and sets in the range of 0.5L UP ≦ L 1 <0.75L UP , the length L 2 of the outlet downstream section 15 0.5L DOWN ≦ L 2 <0.75L DOWN 7 and 8, the purification performance and the PM collection efficiency can be maintained at high levels without excessively increasing the pressure loss.
上記の排ガス浄化装置は、PMの捕集効率を向上させつつ圧力損失を減少させるという目的を達成しうる。なお、この目的に限らず「発明を実施するための形態」に示す各構成から導き出される作用効果であって、従来の技術では得られない作用効果を奏することも、上記の排ガス浄化装置によって達成される他の目的として位置付けることができる。
The exhaust gas purifying device described above can achieve the object of reducing pressure loss while improving PM collection efficiency. It is to be noted that the above-described exhaust gas purifying apparatus is not limited to this object, and has the function and effect derived from each configuration shown in the “Embodiment for Carrying Out the Invention”. Can be positioned as other purposes.
［２．第二実施形態］
［２－１．構成］
以下、図面を参照して、第二実施形態としての排ガス浄化装置について説明する。本実施形態の排ガス浄化装置３の構造を図９に例示する。隔壁内部１３は、入口セル４に近い側と出口セル５に近い側との二領域に分類される。前者は入口セル４側の隔壁表面（または入口セル４）までの距離が所定値T以下となる部分であり、後者は入口セル４までの距離が所定値Tを超える部分である。所定値Tの値は任意であり、例えば隔壁６の厚みをTWALLとして「T≦0.5TWALL」の関係を満たすように設定される。以下、隔壁内部１３のうち入口セル４に近い側を「内部入口側１８」と呼び、出口セル５に近い側を「内部出口側１９」と呼ぶ。 [2. Second Embodiment]
[2-1. Constitution]
Hereinafter, an exhaust gas purifying apparatus as a second embodiment will be described with reference to the drawings. FIG. 9 illustrates a structure of the exhaustgas purifying apparatus 3 of the present embodiment. The partition interior 13 is classified into two regions, a side near the entrance cell 4 and a side near the exit cell 5. The former is a portion where the distance to the partition wall surface (or the inlet cell 4) on the entrance cell 4 side is equal to or less than a predetermined value T, and the latter is a portion where the distance to the entrance cell 4 exceeds the predetermined value T. The value of the predetermined value T is arbitrary, and is set, for example, so as to satisfy the relationship of “T ≦ 0.5 T WALL ”, where the thickness of the partition wall 6 is T WALL . Hereinafter, the side of the partition interior 13 that is closer to the inlet cell 4 is referred to as “inner inlet side 18”, and the side closer to the outlet cell 5 is referred to as “inner outlet side 19”.
［２－１．構成］
以下、図面を参照して、第二実施形態としての排ガス浄化装置について説明する。本実施形態の排ガス浄化装置３の構造を図９に例示する。隔壁内部１３は、入口セル４に近い側と出口セル５に近い側との二領域に分類される。前者は入口セル４側の隔壁表面（または入口セル４）までの距離が所定値T以下となる部分であり、後者は入口セル４までの距離が所定値Tを超える部分である。所定値Tの値は任意であり、例えば隔壁６の厚みをTWALLとして「T≦0.5TWALL」の関係を満たすように設定される。以下、隔壁内部１３のうち入口セル４に近い側を「内部入口側１８」と呼び、出口セル５に近い側を「内部出口側１９」と呼ぶ。 [2. Second Embodiment]
[2-1. Constitution]
Hereinafter, an exhaust gas purifying apparatus as a second embodiment will be described with reference to the drawings. FIG. 9 illustrates a structure of the exhaust
隔壁６の表面には、入口セル４側と出口セル５側とで異なる触媒層が形成される。図２，図９に示すように、担体７の隔壁表面のうち、入口セル４に面する側の上流側には、入口上流部１４が設けられる。入口上流部１４は、入口端面１１から入口セル４の最奥部よりも手前までの範囲をカバーするように設けられる。つまり、入口セル４に面する隔壁表面のうち、入口上流部１４よりも出口端面１２側には触媒９が担持されない。側面視での入口上流部１４の長さL1は、入口セルの全長LUPに対して少なくとも「0<L1<LUP」の関係を満たし、好ましくは「0.5LUP≦L1<0.75LUP」の関係を満たすように設定される。
Different catalyst layers are formed on the surface of the partition 6 on the inlet cell 4 side and the outlet cell 5 side. As shown in FIGS. 2 and 9, an inlet upstream portion 14 is provided on the upstream side of the partition wall surface of the carrier 7 facing the inlet cell 4. The inlet upstream portion 14 is provided so as to cover a range from the inlet end face 11 to a position closer to the front than the innermost portion of the inlet cell 4. That is, the catalyst 9 is not carried on the outlet end face 12 side of the inlet upstream portion 14 in the partition wall surface facing the inlet cell 4. The length L 1 of the inlet upstream portion 14 in side view satisfies the relationship of at least "0 <L 1 <L UP" to the total length L UP inlet cells, preferably "0.5 L UP ≦ L 1 <0.75 L UP ”.
図９に示すように、入口上流部１４は基層１６と表層１７とを含む多層構造にしてもよい。この場合、表層１７は入口セル４に接触している入口上流部１４の表面、あるいはその表面に近い部分（その表面までの距離が第二所定値以下となる部分）である。基層１６は、表層１７よりも担体７側に位置する部分であって、好ましくは担体７に接触するように設けられる。図９に示す例では、表層１７以外の部分が基層１６になっている。このような多層構造では、基層１６と表層１７とに異なる触媒９を担持させることが好ましい。
As shown in FIG. 9, the inlet upstream section 14 may have a multilayer structure including the base layer 16 and the surface layer 17. In this case, the surface layer 17 is the surface of the inlet upstream portion 14 in contact with the inlet cell 4 or a portion close to the surface (a portion where the distance to the surface is equal to or less than a second predetermined value). The base layer 16 is a portion located closer to the carrier 7 than the surface layer 17, and is preferably provided so as to be in contact with the carrier 7. In the example shown in FIG. 9, a portion other than the surface layer 17 is the base layer 16. In such a multilayer structure, it is preferable to support different catalysts 9 on the base layer 16 and the surface layer 17.
また、担体７の隔壁表面のうち、出口セル５に面する側の下流側には、出口下流部１５が設けられる。出口下流部１５は、出口端面１２から出口セル５の最奥部よりも手前までの範囲をカバーするように設けられる。つまり、出口セル５に面する隔壁表面のうち、出口下流部１５よりも入口端面１１側には触媒９が担持されない。側面視での出口下流部１５の長さL2は、出口セルの全長LDOWNに対して少なくとも「0<L2<LDOWN」の関係を満たし、好ましくは「0.5LDOWN≦L2<0.75LDOWN」の関係を満たすように設定される。
An outlet downstream portion 15 is provided on the downstream side of the partition wall surface of the carrier 7 facing the outlet cell 5. The outlet downstream part 15 is provided so as to cover a range from the outlet end face 12 to a position closer to the front than the innermost part of the outlet cell 5. That is, the catalyst 9 is not carried on the inlet end face 11 side of the outlet downstream portion 15 in the partition wall surface facing the outlet cell 5. The length L 2 of the outlet downstream section 15 in side view satisfies the relationship of at least "0 <L 2 <L DOWN" to the total length L DOWN outlet cells, preferably "0.5 L DOWN ≦ L 2 <0.75 L DOWN ”.
より好ましくは、図２，図９に示すように、入口上流部１４と出口下流部１５とが側面視で上下方向にオーバーラップして配置される。例えば、側面視での入口セル４の全長LUPに対して、入口上流部１４の長さL1を60％とする。また、出口セル５の全長LDOWNに対して、出口下流部１５の長さL2も60％とする。この場合、入口上流部１４の下流端部と出口下流部１５の上流端部とが図２，図９中で上下方向にオーバーラップした状態となる。これにより、入口上流部１４や出口下流部１５の近傍を通過せずに流出する排ガスの量が減少し、PM捕集効率や排ガス浄化効率が向上する。
More preferably, as shown in FIGS. 2 and 9, the inlet upstream portion 14 and the outlet downstream portion 15 are arranged so as to overlap in the vertical direction in a side view. For example, with respect to the total length L UP inlet cells 4 in side view, the length L 1 of the inlet upstream section 14 and 60%. Further, the length L 2 of the outlet downstream portion 15 is also set to 60% of the total length L DOWN of the outlet cell 5. In this case, the downstream end portion of the inlet upstream portion 14 and the upstream end portion of the outlet downstream portion 15 overlap each other in the vertical direction in FIGS. As a result, the amount of exhaust gas flowing out without passing near the inlet upstream portion 14 and the outlet downstream portion 15 is reduced, and the PM collection efficiency and the exhaust gas purification efficiency are improved.
ここで、担体７に担持される触媒９の種類について詳述する。
隔壁内部１３には、貴金属触媒が担持される。貴金属の具体例としては、白金族元素〔白金(Pt)，パラジウム(Pd)，ルテニウム(Ru)，ロジウム(Rh)，オスミウム(Os)，イリジウム(Ir)〕や金(Au)，銀(Ag)などが挙げられる。好ましくは、白金よりも触媒性能の高いロジウムやパラジウムが用いられる。図５に示すように、ロジウムやパラジウムは白金よりも担持量あたりの触媒活性（全炭化水素に対する変換効率）が高い。したがって、ロジウムやパラジウムを用いることで、効率的に排ガス浄化性能を高めることができる。なお、ロジウムを用いる場合にはその担持密度を1.0[g/L]程度とする。 Here, the type of thecatalyst 9 supported on the carrier 7 will be described in detail.
A noble metal catalyst is supported in thepartition interior 13. Specific examples of the noble metal include platinum group elements [platinum (Pt), palladium (Pd), ruthenium (Ru), rhodium (Rh), osmium (Os), iridium (Ir)], gold (Au), and silver (Ag). ). Preferably, rhodium or palladium having higher catalytic performance than platinum is used. As shown in FIG. 5, rhodium and palladium have a higher catalytic activity per supported amount (conversion efficiency with respect to total hydrocarbons) than platinum. Therefore, by using rhodium or palladium, the exhaust gas purification performance can be efficiently increased. When rhodium is used, its carrying density is about 1.0 [g / L].
隔壁内部１３には、貴金属触媒が担持される。貴金属の具体例としては、白金族元素〔白金(Pt)，パラジウム(Pd)，ルテニウム(Ru)，ロジウム(Rh)，オスミウム(Os)，イリジウム(Ir)〕や金(Au)，銀(Ag)などが挙げられる。好ましくは、白金よりも触媒性能の高いロジウムやパラジウムが用いられる。図５に示すように、ロジウムやパラジウムは白金よりも担持量あたりの触媒活性（全炭化水素に対する変換効率）が高い。したがって、ロジウムやパラジウムを用いることで、効率的に排ガス浄化性能を高めることができる。なお、ロジウムを用いる場合にはその担持密度を1.0[g/L]程度とする。 Here, the type of the
A noble metal catalyst is supported in the
入口上流部１４には、銀(Ag)，酸化セリウム(CeO2)，銀セリア（Ag/CeO2），希土類元素（Rare-Earth Elements，REE）などを担持させることが好ましい。銀や酸化セリウムはPM燃焼促進材（燃焼促進触媒）として機能し、隔壁内部１３に担持される貴金属よりも低温でPMを燃焼させうる。その他の燃焼促進材の具体例としては、錫セリア(Sn/CeO2)やセリアジルコニア（CeO2/ZrO2）などが挙げられる。一方、希土類元素は、P/Znトラップ（リン及び亜鉛トラップ）として機能し、排ガス中に含まれるリンや亜鉛による被毒を抑制する。なお、銀を用いる場合にはその担持密度を2.0[g/L]程度とする。
It is preferable that silver (Ag), cerium oxide (CeO 2 ), silver ceria (Ag / CeO 2 ), rare earth elements (Rare-Earth Elements, REE), and the like be carried in the inlet upstream portion 14. Silver and cerium oxide function as a PM combustion promoting material (combustion promoting catalyst), and can burn PM at a lower temperature than the noble metal supported in the partition wall interior 13. Specific examples of other combustion promoting materials include tin ceria (Sn / CeO 2 ) and ceria zirconia (CeO 2 / ZrO 2 ). On the other hand, rare earth elements function as P / Zn traps (phosphorus and zinc traps) and suppress poisoning by phosphorus and zinc contained in exhaust gas. When silver is used, its carrying density is about 2.0 [g / L].
前者（銀，酸化セリウム，銀セリア）と後者（希土類）とをともに入口上流部１４に担持させる場合には、前者が含まれる部位を入口セル４側に露出させることが好ましい。例えば図９に示す図中において、希土類元素を含む部位を基層１６とし、銀，酸化セリウム，銀セリアを含む部位を表層１７とすることが好ましい。この場合、希土類元素を含む基層１６をウォッシュコート法で形成した後に、銀，酸化セリウム，銀セリアを含む表層１７を再びウォッシュコート法で形成すればよい。入口セル４側に銀，酸化セリウムを露出させることで、PMの燃焼性が向上する。なお、前者（銀，酸化セリウム，銀セリア）と後者（希土類）とのいずれか一方を入口上流部１４に担持させる場合には、入口上流部１４を多層構造にせずに単層構造とすればよい。
In the case where both the former (silver, cerium oxide, silver ceria) and the latter (rare earth) are supported on the inlet upstream section 14, it is preferable to expose the part containing the former to the inlet cell 4 side. For example, in the diagram shown in FIG. 9, it is preferable that a portion containing a rare earth element be the base layer 16 and a portion containing silver, cerium oxide, and silver ceria be the surface layer 17. In this case, after forming the base layer 16 containing the rare earth element by the wash coat method, the surface layer 17 containing silver, cerium oxide and silver ceria may be formed again by the wash coat method. By exposing silver and cerium oxide to the inlet cell 4 side, PM combustibility is improved. In the case where one of the former (silver, cerium oxide, silver ceria) and the latter (rare earth) is supported on the inlet upstream portion 14, the inlet upstream portion 14 may have a single-layer structure instead of a multilayer structure. Good.
ここでいう希土類元素の具体例としては、スカンジウム(Sc)，イットリウム(Y)，ランタノイド〔ランタン(La)，セリウム(Ce)，プラセオジム(Pr)，ネオジム(Nd)，プロメチウム(Pm)，サマリウム(Sm)，ユウロピウム(Eu)，ガドリニウム(Gd)，テルビウム(Tb)，ジスプロシウム(Dy)，ホルミウム(Ho)，エルビウム(Er)，ツリウム(Tm)，イッテルビウム(Yb)，ルテチウム(Lu)〕が挙げられる。これらの少なくとも一つ以上を入口上流部１４に担持させることで、P/Znトラップ性能が向上する。
Specific examples of the rare earth element here include scandium (Sc), yttrium (Y), lanthanoid [lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium ( Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu)] Can be By supporting at least one of these at the inlet upstream portion 14, the P / Zn trap performance is improved.
出口下流部１５には、貴金属を担持させることが好ましい。出口下流部１５に担持される貴金属の具体例としては、白金族元素〔白金，パラジウム，ルテニウム，ロジウム，オスミウム，イリジウム〕，金，銀などが挙げられる。ここで担持される貴金属の種類は、隔壁内部１３に担持されるものと同一であってもよいし、相違してもよい。好ましくは、ロジウムまたはパラジウムが用いられる。なお、ロジウムを用いる場合にはその担持密度を0.4[g/L]程度とする。
貴 It is preferable that a noble metal is carried in the outlet downstream portion 15. Specific examples of the noble metal supported on the outlet downstream portion 15 include platinum group elements [platinum, palladium, ruthenium, rhodium, osmium, iridium], gold, silver and the like. The type of the noble metal carried here may be the same as or different from that carried on the inside 13 of the partition wall. Preferably, rhodium or palladium is used. When rhodium is used, its loading density is about 0.4 [g / L].
なお、隔壁内部１３にNOxを一時的に吸蔵・吸着するNOxトラップ触媒（窒素酸化物トラップ触媒）を含ませてもよい。NOxトラップ触媒の具体例としては、アルカリ金属やアルカリ土類金属が挙げられる。例えば、バリウム(Ba)，カリウム(K)，ルビジウム(Rb)，ストロンチウム(Sr)，セシウム（Cs），フランシウム(Fr)，ラジウム(Ra)などであり、好ましくはバリウム及びカリウムが併用される。
The NOx trap catalyst (nitrogen oxide trap catalyst) that temporarily stores and adsorbs NOx may be included in the partition interior 13. Specific examples of the NOx trap catalyst include an alkali metal and an alkaline earth metal. For example, barium (Ba), potassium (K), rubidium (Rb), strontium (Sr), cesium (Cs), francium (Fr), radium (Ra) and the like are preferable, and barium and potassium are preferably used in combination.
図６に示すように、カリウムはバリウムよりも高温でのNOx浄化に適しており、燃焼温度の高いガソリンエンジンでの排ガス浄化に適している。また、カリウムはバリウムよりもNO2のトラップ性能が高く、NOx浄化効率が高い。一方、カリウムは熱的に不安定であり、担持位置から落下，飛散することがある。この場合、飛散したカリウムが他の触媒や貴金属の触媒作用（三元活性，特にTHC浄化性能）を阻害しうる。したがって、バリウムとカリウムとを併用することが好ましい。
As shown in FIG. 6, potassium is suitable for NOx purification at a higher temperature than barium, and is suitable for exhaust gas purification in a gasoline engine having a high combustion temperature. Further, potassium has higher NO 2 trapping performance and higher NOx purification efficiency than barium. On the other hand, potassium is thermally unstable and may fall or scatter from the loading position. In this case, the scattered potassium may hinder the catalytic action (ternary activity, particularly THC purification performance) of another catalyst or a noble metal. Therefore, it is preferable to use barium and potassium together.
触媒９の種類と担持位置との組み合わせを、以下の表３～表１０に例示する。ここでは、64種類の実施例（No.21～No.84）を示す。表中の「Pd/Rh」は、パラジウム及びロジウムを含むことを意味する。すべての実施例において、隔壁内部１３に貴金属が含まれている。また、表中の「Ag/CeO2」は、PM燃焼促進触媒である銀セリアを含むことを意味する。銀セリアは、隔壁内部１３や入口上流部１４に担持される（No.22～36，38～52，54～68，70～84）。
Tables 3 to 10 below show combinations of the type of the catalyst 9 and the supporting position. Here, 64 types of embodiments (No. 21 to No. 84) are shown. “Pd / Rh” in the table means that palladium and rhodium are included. In all the embodiments, the noble metal is contained in the partition interior 13. Further, “Ag / CeO 2 ” in the table means that it contains silver ceria which is a PM combustion promotion catalyst. The silver ceria is carried on the inside of the partition wall 13 and on the inlet upstream portion 14 (Nos. 22 to 36, 38 to 52, 54 to 68, 70 to 84).
表中の「Ba/K」は、バリウム及びカリウムを含むことを意味する。バリウム及びカリウムは、隔壁内部１３に担持され、好ましくは少なくとも内部出口側１９に担持される（No.53～84）。また、表中の「REE」は、希土類元素を含むことを意味する。希土類元素は、入口上流部１４に担持される（No.23～24，27～28，31～32，35～36，39～40，42～44，47～48，51～52，55～56，59～60，63～64，67～68，71～72，75～76，79～80，83～84）。入口上流部１４に銀セリアと希土類元素とがともに含まれないものについては、二層構造にする（基層１６及び表層１７を形成する）必要はない。
「" Ba / K "in the table means that it contains barium and potassium. Barium and potassium are supported in the partition interior 13, preferably at least on the internal outlet side 19 (Nos. 53 to 84). “REE” in the table means that rare earth elements are included. The rare earth element is carried in the inlet upstream portion 14 (Nos. 23 to 24, 27 to 28, 31 to 32, 35 to 36, 39 to 40, 42 to 44, 47 to 48, 51 to 52, 55 to 56). , 59-60, 63-64, 67-68, 71-72, 75-76, 79-80, 83-84). If the entrance upstream portion 14 does not contain both silver ceria and a rare earth element, it is not necessary to form a two-layer structure (forming the base layer 16 and the surface layer 17).
表３～表１０中の空欄は、触媒非担持としてもよいし、何らかの触媒（例えば白金，遷移金属硫酸塩，アルカリ金属硫酸塩など）を担持させてもよい。ただし、少なくともNo.21，No.37，No.53，No.69の入口上流部１４については、何らかのPM燃焼促進触媒〔例えば、銀(Ag)，酸化セリウム(CeO2)，錫セリア(Sn/CeO2)，セリアジルコニア（CeO2/ZrO2）など〕が担持されているものとする。したがって、すべての実施例は担体７上に何らかのPM燃焼促進触媒を含む。
In the blanks in Tables 3 to 10, a catalyst may not be supported, or some catalyst (for example, platinum, transition metal sulfate, alkali metal sulfate, etc.) may be supported. However, at least at the inlet upstream portion 14 of No. 21, No. 37, No. 53, No. 69, some PM combustion promoting catalyst [for example, silver (Ag), cerium oxide (CeO 2 ), tin ceria (Sn / CeO 2 ) and ceria zirconia (CeO 2 / ZrO 2 ). Therefore, all embodiments include some PM combustion promoting catalyst on the support 7.
バリウム及びカリウムを含まない実施例は表３～表６に記載されており、バリウム及びカリウムを含む実施例は表７～表１０に記載されている。また、出口下流部１５に貴金属を含まない実施例は表３～表４に記載されており、出口下流部１５に貴金属を含む実施例は表５～表１０に記載されている。また、内部出口側１９に銀セリアを含まない実施例は表３，表５，表７，表９に記載されており、内部出口側１９に銀セリアを含む実施例は表４，表６，表８，表１０に記載されている。
@Examples that do not include barium and potassium are described in Tables 3-6, and examples that include barium and potassium are described in Tables 7-10. Examples in which the outlet downstream portion 15 does not include a noble metal are described in Tables 3 and 4, and examples in which the outlet downstream portion 15 includes a noble metal are described in Tables 5 to 10. Examples in which silver ceria is not included in the internal outlet side 19 are described in Tables 3, 5, 7, and 9; examples in which silver ceria is included in the internal outlet side 19 are shown in Tables 4, 6, and 6. It is described in Tables 8 and 10.
上記のすべての実施例（No.21～84）において、PM燃焼促進触媒が下流側よりも上流側で高密度に担持される。ここでいう上流側及び下流側とは、排ガスの流れ方向を基準とした上流（流通元）及び下流（流通先）である。PM燃焼促進触媒の担持密度を設定するための具体的な手法としては、例えば以下の(A)～(G)が考えられる。
に お い て In all of the above examples (Nos. 21 to 84), the PM combustion promoting catalyst is supported at a higher density on the upstream side than on the downstream side. Here, the upstream side and the downstream side are an upstream (distribution source) and a downstream (distribution destination) based on the flow direction of the exhaust gas. As specific methods for setting the loading density of the PM combustion promoting catalyst, for example, the following (A) to (G) can be considered.
(A) 入口上流部１４において、基層１６（下流側）よりも表層１７（上流側）で高密度に担持する。
(B) 隔壁内部１３において、内部出口側１９（下流側）よりも内部入口側１８（上流側）で高密度に担持する。
(C) 入口上流部１４及び隔壁内部１３において、表層１７,基層１６，内部入口側１８，内部出口側１９の順に担持密度が低くなるように担持する。 (A) In the inletupstream portion 14, the carrier is supported at a higher density on the surface layer 17 (upstream side) than on the base layer 16 (downstream side).
(B) In thepartition interior 13, the carrier is carried at a higher density on the inner inlet side 18 (upstream side) than on the inner outlet side 19 (downstream side).
(C) In theupstream part 14 of the inlet and the inside 13 of the partition wall, the support is carried out such that the carrying density becomes lower in the order of the surface layer 17, the base layer 16, the inner inlet side 18, and the inner outlet side 19.
(B) 隔壁内部１３において、内部出口側１９（下流側）よりも内部入口側１８（上流側）で高密度に担持する。
(C) 入口上流部１４及び隔壁内部１３において、表層１７,基層１６，内部入口側１８，内部出口側１９の順に担持密度が低くなるように担持する。 (A) In the inlet
(B) In the
(C) In the
(D) 表層１７において、基層１６に近い部分（下流側）よりも表面（上流側）で高密度に担持する。
(E) 基層１６において、表層１７から遠い部分（下流側）よりも表層１７に近い部分（上流側）で高密度に担持する。
(F) 内部入口側１８において、入口セル４から遠い部分（下流側）よりも入口セル４に近い部分（上流側）で高密度に担持する。
(G) 内部出口側１９において、出口セル５に近い部分（下流側）よりも出口セル５から遠い部分（上流側）で高密度に担持する。 (D) In thesurface layer 17, it is carried at a higher density on the surface (upstream side) than on the portion (downstream side) near the base layer 16.
(E) In thebase layer 16, a higher density is supported on a portion (upstream side) closer to the surface layer 17 than on a portion (downstream side) farther from the surface layer 17.
(F) On theinner inlet side 18, the carrier is carried at a higher density in a portion (upstream side) closer to the inlet cell 4 than in a portion (downstream side) farther from the inlet cell 4.
(G) On theinner outlet side 19, the carrier is carried at a higher density in a portion (upstream side) farther from the outlet cell 5 than in a portion (downstream side) closer to the outlet cell 5.
(E) 基層１６において、表層１７から遠い部分（下流側）よりも表層１７に近い部分（上流側）で高密度に担持する。
(F) 内部入口側１８において、入口セル４から遠い部分（下流側）よりも入口セル４に近い部分（上流側）で高密度に担持する。
(G) 内部出口側１９において、出口セル５に近い部分（下流側）よりも出口セル５から遠い部分（上流側）で高密度に担持する。 (D) In the
(E) In the
(F) On the
(G) On the
図１０は、PM燃焼促進触媒の担持密度の設定例を示すグラフである。図１０中の破線は、上記の(A)及び(D)に従った設定に対応する。また、図１０中の一点鎖線は、上記の(B)及び(F)に従った設定に対応し、太実線は上記の(C)～(G)に従った設定に対応する。このように、PMの堆積しやすい上流側に担持されるPM燃焼促進触媒の担持密度を下流側よりも高密度にすることで、担体７の上流側と下流側とでPMが均一に燃焼しやすくなる。これにより、同程度の焼却時間で担体７の各所に堆積していたPMが焼却されやすくなり、局所的な過昇温の発生が防止される。
FIG. 10 is a graph showing a setting example of the carrying density of the PM combustion promoting catalyst. The broken lines in FIG. 10 correspond to the settings according to the above (A) and (D). The dashed line in FIG. 10 corresponds to the setting according to the above (B) and (F), and the thick solid line corresponds to the setting according to the above (C) to (G). In this way, by making the carrying density of the PM combustion promoting catalyst carried on the upstream side where the PM tends to accumulate higher than on the downstream side, the PM is uniformly burned on the upstream side and the downstream side of the carrier 7. It will be easier. This makes it easier for the PM accumulated at various places of the carrier 7 to be incinerated in the same incineration time, thereby preventing local excessive temperature rise.
また、NOxトラップ触媒としてバリウム及びカリウムを含む上記の実施例（No.53～84）において、NOxトラップ触媒を上流側よりも下流側で高密度に担持させてもよい。NOxトラップ触媒の担持密度を設定するための具体的な手法としては、例えば以下の(H)～(J)が考えられる。
に お い て In addition, in the above embodiments (Nos. 53 to 84) containing barium and potassium as the NOx trap catalyst, the NOx trap catalyst may be supported at a higher density on the downstream side than on the upstream side. Specific methods for setting the loading density of the NOx trap catalyst include, for example, the following (H) to (J).
(H) 隔壁内部１３において、内部入口側１８（上流側）よりも内部出口側１９（下流側）で高密度に担持する。
(I) 内部出口側１９において、出口セル５から遠い部分（上流側）よりも出口セル５に近い部分（下流側）で高密度に担持する。
(J) 内部入口側１８において、入口セル４に近い部分（上流側）よりも入口セル４から遠い部分（下流側）で高密度に担持する。 (H) In thepartition interior 13, the carrier is carried at a higher density on the internal outlet side 19 (downstream side) than on the internal inlet side 18 (upstream side).
(I) On theinner outlet side 19, the carrier is carried at a higher density in a portion (downstream side) closer to the outlet cell 5 than in a portion (upstream side) farther from the outlet cell 5.
(J) On theinner inlet side 18, a higher density is carried at a portion (downstream side) farther from the inlet cell 4 than at a portion (upstream side) closer to the inlet cell 4.
(I) 内部出口側１９において、出口セル５から遠い部分（上流側）よりも出口セル５に近い部分（下流側）で高密度に担持する。
(J) 内部入口側１８において、入口セル４に近い部分（上流側）よりも入口セル４から遠い部分（下流側）で高密度に担持する。 (H) In the
(I) On the
(J) On the
図１１は、NOxトラップ触媒の担持密度の設定例を示すグラフである。図１１中の破線は上記の(H)に従った設定に対応し、一点鎖線は上記の(H)～(I)に従った設定に対応し、実線は上記の(H)～(J)に従った設定に対応する。このように、隔壁内部１３に担持されるNOxトラップ触媒の担持密度を上流側よりも下流側で高密度に設定することで、NOxスリップが効果的に抑制される。
FIG. 11 is a graph showing a setting example of the carrying density of the NOx trap catalyst. The dashed line in FIG. 11 corresponds to the setting according to the above (H), the dashed line corresponds to the setting according to the above (H) to (I), and the solid line is the above (H) to (J). Corresponds to the setting according to. As described above, by setting the loading density of the NOx trap catalyst loaded in the partition interior 13 to be higher on the downstream side than on the upstream side, NOx slip is effectively suppressed.
なお、バリウム及びカリウムの含有割合は、図１２に示すように担体７の部位ごとに相違させてもよい。すなわち、バリウムの含有割合を上流側で高く設定するとともに下流側で低く設定してもよい。言い換えれば、カリウムの含有割合を上流側で低く設定するとともに下流側で高く設定してもよい。このような設定により、カリウムの飛散による他の触媒作用の低下が抑制される。
The content ratio of barium and potassium may be different for each part of the carrier 7 as shown in FIG. That is, the barium content may be set high on the upstream side and low on the downstream side. In other words, the potassium content may be set low on the upstream side and high on the downstream side. Such a setting suppresses a decrease in other catalytic action due to the scattering of potassium.
［２－２．作用・効果］
担体上に捕集されるPMの分布は必ずしも均一ではなく、担体の形状や排ガスの流れ方などに応じた偏りが生じる。例えば、ウォールフロー型の担体では、入口セルに面した担体表面や、担体内部における排ガス流路の入口付近にPMが堆積しやすい。そのため、担体の上流側と下流側とでPMを均一に燃焼させることが難しいという課題がある。なお、PMの堆積量が増大しやすい上流側ほど焼却時間が長引きやすく、過昇温による性能低下のリスクがある。 [2-2. Action / Effect]
The distribution of PM collected on the carrier is not necessarily uniform, and a deviation occurs depending on the shape of the carrier, the flow of exhaust gas, and the like. For example, in the case of a wall flow type carrier, PM easily accumulates on the surface of the carrier facing the inlet cell or near the inlet of the exhaust gas flow path inside the carrier. Therefore, there is a problem that it is difficult to burn PM uniformly on the upstream side and the downstream side of the carrier. It should be noted that the incineration time is prolonged more easily on the upstream side where the deposition amount of PM tends to increase, and there is a risk of performance degradation due to excessive heating.
担体上に捕集されるPMの分布は必ずしも均一ではなく、担体の形状や排ガスの流れ方などに応じた偏りが生じる。例えば、ウォールフロー型の担体では、入口セルに面した担体表面や、担体内部における排ガス流路の入口付近にPMが堆積しやすい。そのため、担体の上流側と下流側とでPMを均一に燃焼させることが難しいという課題がある。なお、PMの堆積量が増大しやすい上流側ほど焼却時間が長引きやすく、過昇温による性能低下のリスクがある。 [2-2. Action / Effect]
The distribution of PM collected on the carrier is not necessarily uniform, and a deviation occurs depending on the shape of the carrier, the flow of exhaust gas, and the like. For example, in the case of a wall flow type carrier, PM easily accumulates on the surface of the carrier facing the inlet cell or near the inlet of the exhaust gas flow path inside the carrier. Therefore, there is a problem that it is difficult to burn PM uniformly on the upstream side and the downstream side of the carrier. It should be noted that the incineration time is prolonged more easily on the upstream side where the deposition amount of PM tends to increase, and there is a risk of performance degradation due to excessive heating.
このような課題に対し、燃焼促進触媒を上流側で高密度に担持させることで、PM（粒子状物質）を効率的に燃焼させることができ、PMの浄化効率及び排ガス浄化性能を効率的に高めることができる。具体的にいえば、上記の排ガス浄化装置は、以下のような種々の作用，効果を奏する。
In order to solve such problems, the PM (particulate matter) can be efficiently burned by supporting the combustion promoting catalyst at a high density on the upstream side, and the purification efficiency of PM and the purification efficiency of exhaust gas can be improved efficiently. Can be enhanced. More specifically, the exhaust gas purifying apparatus described above has various functions and effects as described below.
まず、第二実施形態においても、図７(A)～(C)，図８(A)～(C)に示す関係が認められ、出口下流部１５の好ましい長さL2の範囲は0.5LDOWN≦L2<0.75LDOWNであると考えられる。出口下流部１５が出口セル５の全長LDOWNにわたる広範囲に形成されない場合であっても、隔壁内部１３の貴金属担持量を調節することで良好な排ガス浄化性能が維持されうる。また、入口上流部１４の好ましい長さL1の範囲は0.5LUP≦L1<0.75LUPであると考えられる。
First, also in the second embodiment, FIG. 7 (A) ~ (C) , observed the relationship shown in FIG. 8 (A) ~ (C) , preferably the length L 2 range of outlet downstream section 15 0.5L It is considered that DOWN ≦ L 2 <0.75L DOWN . Even when the outlet downstream portion 15 is not formed in a wide area over the entire length L DOWN of the outlet cell 5, good exhaust gas purification performance can be maintained by adjusting the amount of noble metal carried in the partition interior 13. Also preferred length range L 1 of the inlet upstream section 14 is considered to be 0.5L UP ≦ L 1 <0.75L UP .
（１）図１０に示すように、PM燃焼促進触媒を上流側で高密度に担持させることで、PMを効率的に燃焼させることができ、排ガス浄化性能を効率的に高めることができる。特に、PMが堆積しやすい上流側での迅速な着火を促すことができ、燃焼のきっかけを生じやすくすることができる。これにより、担体７の上流側と下流側とでPMを均一に燃焼させることができ、焼却時間を上流側と下流側とでほぼ同程度にすることができる。これにより、局所的な過昇温の発生を防止することができ、排ガス浄化性能を効率的に高めることができる。
(1) As shown in FIG. 10, by carrying the PM combustion promoting catalyst at a high density on the upstream side, PM can be efficiently burned, and the exhaust gas purification performance can be efficiently improved. In particular, quick ignition on the upstream side where PM is likely to accumulate can be promoted, and combustion can be easily triggered. Thereby, the PM can be uniformly burned on the upstream side and the downstream side of the carrier 7, and the incineration time can be made substantially the same between the upstream side and the downstream side. As a result, local overheating can be prevented, and the exhaust gas purification performance can be efficiently increased.
（２）表３～表１０のNo.25～36，41～52，57～68，73～84に示すように、隔壁内部１３にPM燃焼促進触媒を担持させることで、隔壁内部１３に堆積したPMをより低温な状態で燃焼させることができる。したがって、PM燃焼効率を高めることができるとともに、PMによる目詰まりや圧損上昇を防止することができる。
（３）隔壁内部１３でPMが堆積しやすい内部入口側１８にPM燃焼促進触媒を担持させることで、PM燃焼効率をさらに高めることができる。 (2) As shown in Tables 3 to 10, Nos. 25 to 36, 41 to 52, 57 to 68, and 73 to 84, the PM combustion promotion catalyst is supported on the inside 13 of the partition wall to deposit it on the inside 13 of the partition wall. The burned PM can be burned at a lower temperature. Therefore, PM combustion efficiency can be improved, and clogging and pressure loss increase due to PM can be prevented.
(3) The PM combustion efficiency can be further increased by supporting the PM combustion promoting catalyst on theinner inlet side 18 where PM easily accumulates inside the partition wall 13.
（３）隔壁内部１３でPMが堆積しやすい内部入口側１８にPM燃焼促進触媒を担持させることで、PM燃焼効率をさらに高めることができる。 (2) As shown in Tables 3 to 10, Nos. 25 to 36, 41 to 52, 57 to 68, and 73 to 84, the PM combustion promotion catalyst is supported on the inside 13 of the partition wall to deposit it on the inside 13 of the partition wall. The burned PM can be burned at a lower temperature. Therefore, PM combustion efficiency can be improved, and clogging and pressure loss increase due to PM can be prevented.
(3) The PM combustion efficiency can be further increased by supporting the PM combustion promoting catalyst on the
（４）排ガス中のPMとの接触確率が最も高い入口上流部１４にPM燃焼促進触媒を担持させることで、PM燃焼効率をさらに高めることができるとともに、例えば冷態始動直後の担体７を早期に昇温させることができる。また、PMが隔壁内部１３に進入する前に燃焼させることが可能となり、排気通路２の圧力損失を低減させることができる。したがって、総合的な排ガス浄化性能を高めることができる。
(4) The PM combustion promoting catalyst can be carried in the inlet upstream portion 14 having the highest probability of contact with PM in the exhaust gas, so that the PM combustion efficiency can be further improved. Temperature. Further, the PM can be burned before entering the partition interior 13, and the pressure loss in the exhaust passage 2 can be reduced. Therefore, comprehensive exhaust gas purification performance can be improved.
（５）表５～表１０のNo.37～84に示すように、出口下流部１５に貴金属触媒を含ませることで、出口セル５側でのNOx還元効率を高めることができる。これにより、排ガス浄化装置３からのNOxのスリップ量を減少させることができ、排ガス浄化性能を効率的に高めることができる。
(5) As shown in Nos. 37 to 84 in Tables 5 to 10, the NOx reduction efficiency on the outlet cell 5 side can be increased by including a noble metal catalyst in the outlet downstream portion 15. As a result, the amount of slip of NOx from the exhaust gas purification device 3 can be reduced, and the exhaust gas purification performance can be efficiently increased.
（６）図２，図９に示すように、入口上流部１４と出口下流部１５とを側面視で上下方向にオーバーラップさせることで、PM捕集効率や排ガス浄化効率を高めることができる。なお、入口上流部１４の長さL1を0.5LUP≦L1<0.75LUPの範囲内で設定するとともに、出口下流部１５の長さL2を0.5LDOWN≦L2<0.75LDOWNの範囲内で設定すれば、図７～図８に示すように、圧力損失を過度に上昇させることなく浄化性能とPM捕集効率とを高い水準に維持することができる。
(6) As shown in FIGS. 2 and 9, the PM upstream efficiency and the exhaust gas purification efficiency can be increased by vertically overlapping the inlet upstream portion 14 and the outlet downstream portion 15 in a side view. Incidentally, the length L 1 of the inlet upstream section 14 and sets in the range of 0.5L UP ≦ L 1 <0.75L UP , the length L 2 of the outlet downstream section 15 0.5L DOWN ≦ L 2 <0.75L DOWN 7 and 8, the purification performance and the PM collection efficiency can be maintained at high levels without excessively increasing the pressure loss.
（７）表７～表１０のNo.53～84に示すように、隔壁内部１３にNOxトラップ触媒（バリウム及びカリウム）を含ませることで、隔壁内部１３のNOx吸蔵量を増加させることができる。また、隔壁内部１３には貴金属も含まれているため、バリウムやカリウムに吸蔵されたNOxをその場で還元することが容易であり、NOx浄化効率を高めることができる。
(7) As shown in Nos. 53 to 84 of Tables 7 to 10, by including a NOx trap catalyst (barium and potassium) in the inside 13 of the partition, the NOx storage amount in the inside 13 of the partition can be increased. . Further, since the noble metal is also contained in the partition interior 13, it is easy to reduce NOx stored in barium or potassium on the spot, and the NOx purification efficiency can be increased.
（８）図１１に示すように、NOxトラップ触媒を下流側で高密度に担持させることで、排ガス浄化装置３からスリップしようとしたNOxをより確実に捕獲することができ、NOxスリップを効果的に抑制することができる。したがって、排ガス浄化装置３からのNOxのスリップ量を減少させることができ、排ガス浄化性能を効率的に高めることができる。
(8) As shown in FIG. 11, by carrying the NOx trap catalyst at a high density on the downstream side, it is possible to more reliably capture the NOx that is about to slip from the exhaust gas purification device 3 and effectively reduce the NOx slip. Can be suppressed. Therefore, the slip amount of NOx from the exhaust gas purification device 3 can be reduced, and the exhaust gas purification performance can be efficiently increased.
（９）図１２に示すように、カリウムの担持割合を下流側で高く設定することで、カリウムの飛散を抑制することができるとともに、飛散による他の触媒作用の低下を防ぐことができる。したがって、排ガス浄化性能を効率的に高めることができる。また、バリウムがカリウムよりも上流側に担持されることから、低温時のNOxトラップ性能を向上させることができる。
(9) As shown in FIG. 12, by setting the carrying ratio of potassium to be higher on the downstream side, it is possible to suppress the scattering of potassium and to prevent a reduction in other catalytic action due to the scattering. Therefore, the exhaust gas purification performance can be efficiently improved. Further, since barium is supported on the upstream side of potassium, the NOx trap performance at low temperatures can be improved.
上記の排ガス浄化装置は、PMを均一に燃焼させるという目的を達成しうる。なお、この目的に限らず「発明を実施するための形態」に示す各構成から導き出される作用効果であって、従来の技術では得られない作用効果を奏することも、上記の排ガス浄化装置によって達成される他の目的として位置付けることができる。
The above exhaust gas purifying device can achieve the purpose of burning PM uniformly. It is to be noted that the above-described exhaust gas purifying apparatus is not limited to this object, and has the function and effect derived from each configuration shown in the “Embodiment for Carrying Out the Invention”. Can be positioned as other purposes.
［３．変形例］
上記の実施形態はあくまでも例示に過ぎず、本実施形態で明示しない種々の変形や技術の適用を排除する意図はない。本実施形態の各構成は、それらの趣旨を逸脱しない範囲で種々変形して実施することができる。また、必要に応じて取捨選択することができ、あるいは適宜組み合わせることができる。 [3. Modification]
The above embodiment is merely an example, and there is no intention to exclude various modifications and application of technology that are not explicitly described in the present embodiment. Each configuration of the present embodiment can be variously modified and implemented without departing from the spirit thereof. Further, they can be selected as needed, or can be appropriately combined.
上記の実施形態はあくまでも例示に過ぎず、本実施形態で明示しない種々の変形や技術の適用を排除する意図はない。本実施形態の各構成は、それらの趣旨を逸脱しない範囲で種々変形して実施することができる。また、必要に応じて取捨選択することができ、あるいは適宜組み合わせることができる。 [3. Modification]
The above embodiment is merely an example, and there is no intention to exclude various modifications and application of technology that are not explicitly described in the present embodiment. Each configuration of the present embodiment can be variously modified and implemented without departing from the spirit thereof. Further, they can be selected as needed, or can be appropriately combined.
上述の実施形態ではエンジン１を搭載した車両１０を例示したが、本件の適用対象は車両１０に限定されない。上記の排ガス浄化装置３は、例えば船舶や航空機などに搭載されるエンジン１の排気通路２に介装させることが可能である。あるいは、発電機や産業用機械に内蔵されるエンジン１の排ガス浄化装置３として利用することができる。
In the above-described embodiment, the vehicle 10 equipped with the engine 1 is illustrated, but the application target of the present invention is not limited to the vehicle 10. The above-mentioned exhaust gas purifying device 3 can be interposed in the exhaust passage 2 of the engine 1 mounted on a ship or an aircraft, for example. Alternatively, it can be used as an exhaust gas purifying device 3 of the engine 1 built in a generator or an industrial machine.
１ エンジン（内燃機関）
２ 排気通路
３ 排ガス浄化装置
４ 入口セル
５ 出口セル
６ 隔壁
７ 担体
８ 目封じ
９ 触媒
１０ 車両
１１ 入口端面
１２ 出口端面
１３ 隔壁内部
１４ 入口上流部
１５ 出口下流部
１６ 基層
１７ 表層
１８ 内部入口側
１９ 内部出口側 1 engine (internal combustion engine)
2Exhaust passage 3 Exhaust gas purifier 4 Inlet cell 5 Outlet cell 6 Partition wall 7 Carrier 8 Sealing 9 Catalyst 10 Vehicle 11 Inlet end surface 12 Outlet end surface 13 Inside partition wall 14 Inlet upstream part 15 Outlet downstream part 16 Base layer 17 Surface layer 18 Internal inlet side 19 Internal exit side
２ 排気通路
３ 排ガス浄化装置
４ 入口セル
５ 出口セル
６ 隔壁
７ 担体
８ 目封じ
９ 触媒
１０ 車両
１１ 入口端面
１２ 出口端面
１３ 隔壁内部
１４ 入口上流部
１５ 出口下流部
１６ 基層
１７ 表層
１８ 内部入口側
１９ 内部出口側 1 engine (internal combustion engine)
2
Claims (16)
- 入口セル及び出口セルを有するウォールフロー型の担体の隔壁内部に貴金属が担持され、内燃機関の排ガスに含まれる粒子状物質を捕集して燃焼させる排ガス浄化装置において、
隔壁表面のうち前記入口セルに面する側の上流側に触媒が担持される入口上流部と、
前記隔壁表面のうち前記出口セルに面する側の下流側に触媒が担持される出口下流部と
を備えることを特徴とする排ガス浄化装置。 Noble metal is carried inside the partition of a wall flow type carrier having an inlet cell and an outlet cell, and in an exhaust gas purifying device that collects and burns particulate matter contained in exhaust gas of an internal combustion engine,
An inlet upstream portion in which a catalyst is supported on an upstream side of the partition wall surface facing the inlet cell,
An exhaust gas purification device, comprising: an outlet downstream portion on which a catalyst is supported, on a downstream side of the partition wall surface facing the outlet cell. - 前記出口下流部が貴金属を含む
ことを特徴とする請求項１記載の排ガス浄化装置。 The exhaust gas purifying apparatus according to claim 1, wherein the downstream portion of the outlet contains a noble metal. - 前記入口上流部が銀または酸化セリウムを含む
ことを特徴とする請求項１または２記載の排ガス浄化装置。 The exhaust gas purifying apparatus according to claim 1 or 2, wherein the upstream portion of the inlet contains silver or cerium oxide. - 前記入口上流部が希土類元素を含む
ことを特徴とする請求項１～３のいずれか１項に記載の排ガス浄化装置。 The exhaust gas purifying apparatus according to any one of claims 1 to 3, wherein the upstream portion of the inlet contains a rare earth element. - 前記入口上流部が銀または酸化セリウムを含む表層と希土類元素を含む基層とを有する
ことを特徴とする請求項３に従属する請求項４に記載の排ガス浄化装置。 The exhaust gas purifying apparatus according to claim 4, wherein the upstream portion of the inlet has a surface layer containing silver or cerium oxide and a base layer containing a rare earth element. - 前記隔壁内部が窒素酸化物をトラップするバリウムまたはカリウムを含む
ことを特徴とする請求項１～５のいずれか１項に記載の排ガス浄化装置。 The exhaust gas purifying apparatus according to any one of claims 1 to 5, wherein the inside of the partition wall contains barium or potassium for trapping nitrogen oxides. - 前記入口上流部と前記出口下流部とが側面視で上下方向にオーバーラップして配置される
ことを特徴とする請求項１～６のいずれか１項に記載の排ガス浄化装置。 The exhaust gas purifying apparatus according to any one of claims 1 to 6, wherein the inlet upstream portion and the outlet downstream portion are arranged so as to overlap in a vertical direction in a side view. - 担体の隔壁内部に貴金属が担持され、内燃機関の排ガスに含まれる粒子状物質を捕集して燃焼させる排ガス浄化装置において、前記粒子状物質の燃焼を促進する燃焼促進触媒が下流側よりも上流側で高密度に担持される
ことを特徴とする排ガス浄化装置。 In an exhaust gas purifying apparatus in which a noble metal is supported inside a partition wall of a carrier and captures and burns particulate matter contained in exhaust gas of an internal combustion engine, a combustion promoting catalyst for promoting the combustion of the particulate matter is provided upstream of a downstream side. An exhaust gas purifying device characterized in that the exhaust gas purifying device is supported at high density on the side. - 前記燃焼促進触媒が前記隔壁内部に担持される
ことを特徴とする請求項８記載の排ガス浄化装置。 The exhaust gas purifying apparatus according to claim 8, wherein the combustion promoting catalyst is carried inside the partition. - 前記担体が入口セル及び出口セルを有するウォールフロー型担体であって、
前記燃焼促進触媒が、前記入口セルまでの距離が所定値以下となる範囲内に担持される
ことを特徴とする請求項８または９記載の排ガス浄化装置。 The carrier is a wall flow type carrier having an inlet cell and an outlet cell,
The exhaust gas purifying apparatus according to claim 8, wherein the combustion promoting catalyst is supported within a range in which a distance to the inlet cell is equal to or less than a predetermined value. - 前記担体の隔壁表面のうち前記入口セルに面する側の上流側に設けられ前記燃焼促進触媒が担持される入口上流部を備える
ことを特徴とする請求項１０記載の排ガス浄化装置。 The exhaust gas purifying apparatus according to claim 10, further comprising an inlet upstream portion provided on an upstream side of the partition wall surface of the carrier facing the inlet cell and carrying the combustion promoting catalyst. - 前記担体の隔壁表面のうち前記出口セルに面する側かつ下流側に設けられ貴金属が担持される出口下流部を備える
ことを特徴とする請求項１０または１１記載の排ガス浄化装置。 The exhaust gas purifying apparatus according to claim 10 or 11, further comprising an outlet downstream portion provided on a side facing the outlet cell and downstream of the partition wall surface of the carrier and supporting a noble metal. - 前記入口上流部と前記出口下流部とが側面視で上下方向にオーバーラップして配置される
ことを特徴とする請求項１１に従属する請求項１２に記載の排ガス浄化装置。 13. The exhaust gas purifying apparatus according to claim 12, wherein the upstream part of the inlet and the downstream part of the outlet are arranged so as to overlap vertically in a side view. - 前記隔壁内部に窒素酸化物をトラップする窒素酸化物トラップ触媒を含む
ことを特徴とする請求項８～１３のいずれか１項に記載の排ガス浄化装置。 14. The exhaust gas purifying apparatus according to claim 8, further comprising a nitrogen oxide trap catalyst for trapping nitrogen oxide inside the partition. - 前記窒素酸化物トラップ触媒が上流側よりも下流側で高密度に担持される
ことを特徴とする請求項１４記載の排ガス浄化装置。 The exhaust gas purifying apparatus according to claim 14, wherein the nitrogen oxide trap catalyst is supported at a higher density on a downstream side than on an upstream side. - 前記窒素酸化物トラップ触媒がバリウム及びカリウムを含み、前記窒素酸化物トラップ触媒の全体に対する前記カリウムの含有割合が上流側よりも下流側で高く設定される
ことを特徴とする請求項１４または１５記載の排ガス浄化装置。
The said nitrogen oxide trap catalyst contains barium and potassium, The content rate of the said potassium with respect to the whole of this nitrogen oxide trap catalyst is set higher downstream than an upstream, The Claim 14 or 15 characterized by the above-mentioned. Exhaust gas purification equipment.
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| JP2018-188915 | 2018-10-04 | ||
| JP2018188914A JP2020056381A (en) | 2018-10-04 | 2018-10-04 | Exhaust emission control device |
| JP2018-188914 | 2018-10-04 | ||
| JP2018188915A JP7167614B2 (en) | 2018-10-04 | 2018-10-04 | Exhaust gas purifier |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| EP4015064A1 (en) * | 2020-12-15 | 2022-06-22 | UMICORE AG & Co. KG | Catalytically active particle filter with high filtration efficiency |
| WO2022129010A1 (en) * | 2020-12-15 | 2022-06-23 | Umicore Ag & Co. Kg | Catalytically active particle filter with a high degree of filtration efficiency |
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