PH12018000215A1 - Exhaust gas cleaning system - Google Patents
Exhaust gas cleaning system Download PDFInfo
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- PH12018000215A1 PH12018000215A1 PH12018000215A PH12018000215A PH12018000215A1 PH 12018000215 A1 PH12018000215 A1 PH 12018000215A1 PH 12018000215 A PH12018000215 A PH 12018000215A PH 12018000215 A PH12018000215 A PH 12018000215A PH 12018000215 A1 PH12018000215 A1 PH 12018000215A1
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- Philippines
- Prior art keywords
- catalytic reduction
- selective catalytic
- scr
- reduction device
- exhaust gas
- Prior art date
Links
- 238000004140 cleaning Methods 0.000 title claims abstract description 38
- 238000010531 catalytic reduction reaction Methods 0.000 claims abstract description 37
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 37
- 239000003054 catalyst Substances 0.000 claims abstract description 26
- 238000002485 combustion reaction Methods 0.000 claims abstract description 20
- 238000011144 upstream manufacturing Methods 0.000 claims abstract description 12
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 10
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims abstract description 10
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052802 copper Inorganic materials 0.000 claims abstract description 8
- 239000010949 copper Substances 0.000 claims abstract description 8
- 239000003795 chemical substances by application Substances 0.000 claims 1
- 239000007789 gas Substances 0.000 description 43
- 229940124024 weight reducing agent Drugs 0.000 description 32
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical group N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 31
- WTHDKMILWLGDKL-UHFFFAOYSA-N urea;hydrate Chemical compound O.NC(N)=O WTHDKMILWLGDKL-UHFFFAOYSA-N 0.000 description 23
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 20
- 229910021529 ammonia Inorganic materials 0.000 description 17
- 238000006722 reduction reaction Methods 0.000 description 15
- 231100000572 poisoning Toxicity 0.000 description 14
- 230000000607 poisoning effect Effects 0.000 description 14
- 229910002089 NOx Inorganic materials 0.000 description 13
- 239000000446 fuel Substances 0.000 description 13
- 230000009467 reduction Effects 0.000 description 11
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- 238000000034 method Methods 0.000 description 8
- 230000008569 process Effects 0.000 description 8
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 7
- 239000010970 precious metal Substances 0.000 description 6
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 5
- 229910052717 sulfur Inorganic materials 0.000 description 5
- 239000011593 sulfur Substances 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 229910001868 water Inorganic materials 0.000 description 5
- 239000004215 Carbon black (E152) Substances 0.000 description 4
- 229930195733 hydrocarbon Natural products 0.000 description 4
- 150000002430 hydrocarbons Chemical class 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- 239000000919 ceramic Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000006870 function Effects 0.000 description 3
- 230000007062 hydrolysis Effects 0.000 description 3
- 238000006460 hydrolysis reaction Methods 0.000 description 3
- 238000012805 post-processing Methods 0.000 description 3
- MGWGWNFMUOTEHG-UHFFFAOYSA-N 4-(3,5-dimethylphenyl)-1,3-thiazol-2-amine Chemical compound CC1=CC(C)=CC(C=2N=C(N)SC=2)=C1 MGWGWNFMUOTEHG-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 2
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 2
- 239000004202 carbamide Substances 0.000 description 2
- 229910002091 carbon monoxide Inorganic materials 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 description 1
- 229940044927 ceric oxide Drugs 0.000 description 1
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 239000010948 rhodium Substances 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
- F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
- F01N13/0093—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series the purifying devices are of the same type
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
- F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
- F01N3/2066—Selective catalytic reduction [SCR]
-
- 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
- F01N2570/00—Exhaust treating apparatus eliminating, absorbing or adsorbing specific elements or compounds
-
- 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
- F01N2570/00—Exhaust treating apparatus eliminating, absorbing or adsorbing specific elements or compounds
- F01N2570/04—Sulfur or sulfur oxides
-
- 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
- F01N2570/00—Exhaust treating apparatus eliminating, absorbing or adsorbing specific elements or compounds
- F01N2570/14—Nitrogen oxides
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/40—Engine management systems
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Exhaust Gas After Treatment (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Catalysts (AREA)
Abstract
An exhaust gas cleaning system includes: a first selective catalytic reduction device disposed in an exhaust pipe through which exhaust gas discharged from an internal combustion engine passes, the first selective catalytic reduction device including a selective reducing catalyst using vanadium; a first jetting section provided upstream of the first selective catalytic reduction device in the exhaust pipe, the first jetting section being configured to jet reducing agent; and a second selective catalytic reduction device provided downstream of the first selective catalytic reduction device in the exhaust pipe, the second selective catalytic reduction device including a selective reducing catalyst using copper.
Description
metal components (Pt) contained in exhaust gas can be caused to adhere to SCR 23C - on the upstream side so as to maintain at least the NOx-cleaning performance of SCR : 23D on downstream side, and it is thus possible to prevent reduction in NOx-cleaning =~ performance resulting from poisoning in the entire exhaust system 20. -
When a precious metal component adheres to the front surface of SCR 23C, = and the NOx-cleaning performance of SCR 23C is reduced due to oxidization of the = ammonia generated by being jetted from reducing-agent injector 22, the amount of the = ammonia that reaches SCR 23D might be reduced, and in turn, the NOx-cleaning performance of SCR 23D might be reduced. In this case, ammonia is stably supplied to SCR 23D by jetting urea water from reducing-agent injector 26 provided between
SCR 23C and SCR 23D such that the NOx-cleaning performance of SCR 23D is maintained.
Next, with reference to a flowchart of FIG. 2, a jet control process of control section 40 of the present embodiment is described. The jet control process of FIG. 2 is started after internal combustion engine 10 is operated.
First, temperature acquiring section 41 receives a signal output from temperature sensor 24, and acquires the temperature of the exhaust gas that passes through exhaust pipe 21 (step S100). Next, determination section 43 determines whether the temperature acquired by temperature acquiring section 41 is not smaller than a predetermined temperature (e.g. 200°C) (step S120).
When it is determined that the temperature acquired by temperature acquiring section 41 is smaller than the predetermined temperature (NO at step S120), the process is returned to step S100. On the other hand, when the temperature acquired by temperature acquiring section 41 is not smaller than the predetermined temperature (YES at step S120), jet control section 44 controls reducing-agent injector 22 to start pr jetting of urea water (step S140). -
Next, concentration acquiring section 42 receives a signal output from > concentration sensor 25, and acquires the concentration of NOx contained in exhaust a gas that passes through exhaust pipe 21 (step S160). Next, determination section 43 - determines whether the concentration acquired by concentration acquiring section 42 - is not smaller than a predetermined concentration (step S180). Here, the case where = the concentration acquired by concentration acquiring section 42 is not smaller than a = predetermined concentration is a case where there is a possibility of reduction in *
NOx-cleaning performance of SCR 23C resulting from oxidization of ammonia due to the precious metal component adhered to the front surface of SCR 23C.
When it is determined that the concentration acquired by concentration acquiring section 42 is smaller than the predetermined concentration (NO at step
S180), the process is returned to step S180. On the other hand, when the concentration acquired by concentration acquiring section 42 is not smaller than the predetermined concentration (YES at step S180), jet control section 44 controls reducing-agent injector 26 to start jetting of urea water (step S200). Upon completion of the process of step S200, control section 40 terminates the processes of
FIG. 2.
As has been elaborated above, in the present embodiment, an exhaust gas cleaning system includes: a first selective catalytic reduction device (SCR 23C) disposed in an exhaust pipe 21 through which exhaust gas discharged from an internal combustion engine 10 passes, the first selective catalytic reduction device (SCR 23C) including a selective reducing catalyst using vanadium; a first jetting section (reducing-agent injector 22) provided upstream of the first selective catalytic reduction device (SCR 23C) in the exhaust pipe 21, the first jetting section
(reducing-agent injector 22) being configured to jet reducing agent; and a second - selective catalytic reduction device (SCR 23D) provided downstream of the first > selective catalytic reduction device (SCR 23C) in the exhaust pipe 21, the second - selective catalytic reduction device (SCR 23D) including a selective reducing catalyst o using copper. o
According to the above-mentioned configuration of the present embodiment, © poisoning-resistant SCR 23C is disposed on the upstream side in exhaust pipe 21, and ®
SCR 23D that is vulnerable to poisoning but has a higher NOx-cleaning performance - in comparison with SCR 23C is disposed on the downstream side in exhaust pipe 21.
With this configuration, the sulfur components (S) and/or the precious metal components (Pt) contained in exhaust gas can be caused to adhere to SCR 23C on the upstream side so as to at least maintain the NOx-cleaning performance of SCR 23D of the downstream side, and it is thus possible to prevent reduction in NOx-cleaning performance resulting from poisoning in the entire exhaust system 20.
In addition, in the present embodiment, the exhaust gas cleaning system includes: a second jetting section (reducing-agent injector 26) provided between the first selective catalytic reduction device (SCR 23C) and the second selective catalytic reduction device (SCR 23D) in the exhaust pipe 21, the second jetting section (reducing-agent injector 26) being configured to jet reducing agent; and a control section 40 configured to control the second jetting section (reducing-agent injector 26) to jet reducing agent in a case where a NOx concentration of exhaust gas passing between the first selective catalytic reduction device (SCR 23C) and the second selective catalytic reduction device (SCR 23D) is equal to or greater than a predetermined concentration, and controls the second jetting section not to jet the reducing agent in a case where the NOx concentration is smaller than the
- predetermined concentration. = rs
According to the above-mentioned configuration of the present embodiment, = in the case where the NOx concentration of the exhaust gas passing between SCR 23C ” and SCR 23D is a predetermined concentration or greater, and in turn, the - NOx-cleaning performance of SCR 23D might be reduced, urea water is jetted from = reducing-agent injector 26 provided between SCR 23C and SCR 23D. Therefore, = even in the case where the amount of the ammonia that reaches SCR 23D is reduced = due to poisoning of SCR 23C, ammonia can be stably supplied to SCR 23D and the -
NOx-cleaning performance of SCR 23D can be maintained.
While jetting of urea water by reducing-agent injector 26 is started when the concentration acquired by concentration acquiring section 42 is equal to or greater than a predetermined concentration, but jetting of urea water by reducing-agent injector 26 is not started when the concentration acquired by concentration acquiring section 42 is smaller than the predetermined concentration in the present embodiment, the present disclosure is not limited to this. For example, jetting of urea water by reducing-agent injector 26 may be started when the concentration acquired by concentration acquiring section 42 is smaller than the predetermined concentration.
It should be noted that, in view of cost reduction of urea water, prevention of ammonia slip at SCR 23D and the like, it is preferable to minimize the amount of urea water jetted by reducing-agent injector 26. That is, preferably, the amount of jetting of urea water by reducing-agent injector 26 is greater in the case where the concentration acquired by concentration acquiring section 42 is equal to or greater than the predetermined concentration than the case where the concentration acquired by concentration acquiring section 42 is smaller than the predetermined concentration.
The embodiment disclosed herein is merely an exemplification and should not be considered as limitative. The scope of the present invention is specified by the - following claims, not by the above-mentioned description. It should be understood > that various modifications, combinations, sub-combinations and alterations may occur = po depending on design requirements and other factors in so far as they are within the P scope of the appended claims or the equivalents thereof. o
Industrial Applicability 5
The present disclosure is suitable for an exhaust gas cleaning system capable - of preventing reduction in NOx-cleaning performance resulting from poisoning.
Reference Signs List 1 Vehicle 10 Internal combustion engine 11 Combustion chamber 13 Fuel injector 15 Suction valve 17 Exhaust valve 19 Piston
Exhaust system 20 21 Exhaust pipe 22, 26 Reducing-agent injector 23A DOC 23B DPF 23C, 23D SCR 24 Temperature sensor
25 Concentration sensor - 40 Control section > 41 Temperature acquiring section = 42 Concentration acquiring section o 43 Determination section = 44 Jet control section = 50 Suction pipe @
err -
EXHAUST GAS CLEANING SYSTEM -
The present disclosure relates to an exhaust gas cleaning system. ~ os
As an exhaust gas cleaning system for cleaning NOx in the exhaust gas of a = diesel engine mounted in a vehicle such as a truck and a bus, a selective catalytic > reduction (SCR) system has been developed in which urea water or the like is used as reducing agent to reduce NOx to nitrogen and water (see, for example, PTL 1).
A selective catalytic reduction system supplies urea water retained in a urea water tank to an exhaust pipe upstream of a selective catalytic reduction device (SCR), to generate ammonia through hydrolysis of urea with the heat of exhaust gas, and reduce, with the resulting ammonia, NOx by a selective reducing catalyst in the selective catalytic reduction device. The urea water is appropriately jetted with a urea water injector provided at the exhaust passage, for example.
Patent Literature
PTL 1
Japanese Patent Application Laid-Open No. 2000-303826
However, adhesion of sulfur components (S) and/or precious metal components (Pt) contained in the exhaust gas to the front surface of the selective reducing catalyst eee eee might result in reduction in NOx-cleaning performance of the selective reducing catalyst (hereinafter referred to also as poisoning). In particular, when precious 5 ps metal components adhere to the front surface of the selective reducing catalyst, Le ammonia generated by being jetted from the urea water injector is oxidized, and o consequently the NOx-cleaning of the selective reducing catalyst is inhibited. While o it is conceivable to use a selective reducing catalyst using vanadium to prevent such oo poisoning, the NOx-cleaning performance of such a selective reducing catalyst is low, © and as such strict NOx limitation may not be achieved. -
An object of the present disclosure is to provide an exhaust gas cleaning system capable of preventing reduction in NOx-cleaning performance resulting from poisoning.
An exhaust gas cleaning system according to the present disclosure includes: a first selective catalytic reduction device disposed in an exhaust pipe through which exhaust gas discharged from an internal combustion engine passes, the first selective catalytic reduction device including a selective reducing catalyst using vanadium; a first jetting section provided upstream of the first selective catalytic reduction device in the exhaust pipe, the first jetting section being configured to jet reducing agent; and a second selective catalytic reduction device provided downstream of the first selective catalytic reduction device in the exhaust pipe, the second selective catalytic reduction device including a selective reducing catalyst using copper.
According to the present disclosure, reduction in NOx-cleaning performance resulting from poisoning can be prevented. -
Brief Description of Drawings - os
FIG. 1 illustrates a configuration of a vehicle of the present embodiment; and i
FIG. 2 is a flowchart of a jet control process of the present embodiment. -
Description of Embodiment 5
An embodiment of the present disclosure is described below with reference to - the accompanying drawings. FIG. 1 illustrates a configuration of vehicle 1 of the present embodiment. As illustrated in FIG. 1, in vehicle 1 such as a truck and a bus, internal combustion engine 10, exhaust system 20, and control section 40 (more specifically, DSU) are mounted. Exhaust system 20 and control section 40 function as an exhaust gas cleaning system.
First, a configuration of internal combustion engine 10 is described. Internal combustion engine 10 is a diesel engine, for example. In combustion chamber 11 of internal combustion engine 10, fuel injector 13 jets fuel into combustion chamber 11.
It is to be noted that fuel injector 13 may jet fuel to a suction port of combustion chamber 11. Jetting of fuel is controlled by an engine control module (ECM; not illustrated). In addition, with the operation of piston 19, the fuel in combustion chamber 11 is compressed and burned.
Suction valve 15 and exhaust valve 17 are capable of opening and closing.
When suction valve 15 opens, fresh air from suction pipe 50 is sucked into combustion chamber 11. In addition, when exhaust valve 17 opens, exhaust gas resulting from combustion of fuel in combustion chamber 11 is sent out to exhaust system 20 (more specifically, exhaust pipe 21).
Next, a configuration of exhaust system 20 is described. For example, - exhaust system 20 is provided in a lower part of vehicle 1, and mainly includes metal = exhaust pipe 21. Exhaust pipe 21 guides exhaust gas resulting from combustion of . fuel in internal combustion engine 10 to the atmosphere (vehicle outside).
In addition, various post-processing devices for cleaning (purifying) exhaust . gas are provided in exhaust pipe 21. In the present embodiment, the post-processing = devices are DOC (oxidation catalyst) 23A, DPF 23B, SCR 23C (corresponding to & “first selective catalytic reduction device” of the present disclosure), and SCR 23D " (corresponding to “second selective catalytic reduction device” of the present disclosure).
DOC 23A is formed of a metal bearing member supporting rhodium, ceric oxide, platinum, aluminum oxide and the like. DOC 23A decomposes and removes hydrocarbon (HC) and carbon monoxide (CO) contained in exhaust gas. In addition,
DOC 23A also has a function of generating nitrogen dioxide (NO2) by oxidizing
I5 nitrogen monoxide (NO), which is the most part of the NOx contained in exhaust gas.
With this function, the NOx-cleaning efficiency of SCR 23C and SCR 23D can be improved.
On the upstream side (more specifically, the upstream side in the flow direction of the exhaust gas) of DOC 23A in exhaust pipe 21, a fuel supply injector (not illustrated) is disposed as a fuel supply section that temporarily supplies fuel into exhaust gas and oxidizes hydrocarbon (HC) in the fuel with DOC 23A so as to raise the temperature of the exhaust gas by utilizing the oxidation reaction heat.
DPF 23B is composed of a wall flow filter of a monolithic honeycomb type in which the inlets and the outlets of the channels (cells) of the honeycomb made of porous ceramic are alternately closed. DPF 23B collects and removes particulate br matters (PM) contained in exhaust gas. =
In exhaust pipe 21, reducing-agent injector 22 (corresponding to “first jetting @ section” of the present disclosure) for jetting (more specifically, spraying) urea water = as a reducing agent is provided downstream (more specifically, downstream in the . flow direction of the exhaust gas) of DPF 23B, and upstream of SCR 23C. o
It is to be noted that a mixer that mixes and uniformly diffuses, into exhaust gas, = urea water jetted from reducing-agent injector 22 may be provided downstream of = reducing-agent injector 22 in exhaust pipe 21. -
Temperature sensor 24 is provided in a region near the entrance of SCR 23C in exhaust pipe 21. Temperature sensor 24 is used for control of jetting of urea water by reducing-agent injector 22. Temperature sensor 24 detects the temperature of the exhaust gas, and outputs a signal indicating the temperature to control section 40.
For example, SCR 23C has a columnar shape, and includes a honeycomb carrier made of ceramic. A catalyst using vanadium (hereinafter referred to as vanadium catalyst) is borne or coated on the honeycomb wall surface. That is, with the vanadium catalyst, SCR 23C does not easily cause reduction in NOXx-cleaning performance even when sulfur components (S) and/or precious metal components (Pt) contained in exhaust gas adhere to the front surface of SCR 23C (in other words, SCR 23C is resistant to poisoning).
SCR 23C having the above-mentioned configuration is disposed downstream of
DPF 23B in exhaust pipe 21. In addition, at a position between DPF 23B and SCR 23C in exhaust pipe 21, urea water as reducing agent is jetted by reducing-agent injector 22, and supplied to exhaust gas past DPF 23B. As a result, hydrolysis of urea water to ammonia is caused. Regarding exhaust gas containing ammonia in a region near the surface layer of SCR 23C, a reaction of nitrogen oxide (that is, NOx)
to nitrogen and water (reduction reaction) is caused with the effect of the vanadium =o fo catalyst. In this manner, the nitrogen oxide in the exhaust gas is cleaned. =
Here, hydrolysis occurs when the temperature of the exhaust gas passing - through SCR 23C is equal to or higher than a predetermined temperature (e.g. 200°C). ~
Accordingly, in the present embodiment, reducing-agent injector 22 supplies urea = water to the exhaust gas in exhaust pipe 21 when the temperature of the exhaust gas = flowing into SCR 23C is 200°C or above. Jetting of urea water is controlled by = control section 40. It is to be noted that the predetermined temperature (200°C) is ” appropriately set in consideration of the reaction temperature between ammonia and
NOx and the like obtained through experiments, simulations and the like in the phase of design of exhaust system 20.
For example, SCR 23D has a columnar shape, and includes a honeycomb carrier made of ceramic. Catalyst using copper (hereinafter referred to as copper catalyst) is borne or coated on the honeycomb wall surface. That is, with the copper catalyst, SCR 23D relatively easily causes reduction in NOx-cleaning performance (i.e. vulnerable to poisoning) when sulfur components (S) and/or precious metal components (Pt) contained in exhaust gas adhere to the front surface of SCR 23D in comparison with SCR 23C including the vanadium catalyst. Meanwhile, the
NOx-cleaning performance of SCR 23D is higher than that of SCR 23C.
Regarding slipping ammonia, which comes from SCR 23C without being used for reduction reaction, a reaction of nitrogen oxide (so-called NOx) to nitrogen and water (reduction reaction) is caused in a region near the surface layer of SCR 23D with the effect of the copper catalyst. In this manner, the nitrogen oxide in the exhaust gas is cleaned.
It is to be noted that a slipping-ammonia catalyst that oxidizes and removes the slipping ammonia may be disposed downstream of SCR 23D so that slipping - ammonia which has not been used for reduction reaction in SCRs 23C and 23D is not > emitted to the atmosphere. >
Concentration sensor 25 is provided between SCR 23C and SCR 23D in " exhaust pipe 21. Concentration sensor 25 detects the concentration of the NOx =o contained in exhaust gas past SCR 23C, and outputs a signal indicating the = concentration to control section 40. =
In addition, reducing-agent injector 26 (which corresponds to “second jetting - section” of the present disclosure) for jetting urea water as reducing agent is provided between SCR 23C and SCR 23D in exhaust pipe 21.
The water, nitrogen, carbon dioxide generated from the exhaust gas processed by the above-mentioned post-processing devices are discharged to the atmosphere through a muffler (not illustrated) or the like.
Control section 40 includes a work memory such as a random access memory (RAM), a read only memory (ROM) that stores a control program, a central processing unit (CPU) and the like. The CPU reads a control program from the
ROM, loads the program in the RAM, and controls execution of various types of processes in conjunction with the loaded control program.
As illustrated in FIG. 1, control section 40 includes temperature acquiring section 41, concentration acquiring section 42, determination section 43 and jet control section 44.
As described above, in exhaust pipe 21, SCR 23C that is resistant to poisoning is disposed on the upstream side, and SCR 23D that is vulnerable to poisoning but has a higher NOx-cleaning performance in comparison with SCR 23C is disposed on the downstream side. With this configuration, sulfur components (S) and/or precious
Claims (3)
1. An exhaust gas cleaning system comprising: 5 a first selective catalytic reduction device disposed in an exhaust pipe through i. which exhaust gas discharged from an internal combustion engine jasses, the first t- selective catalytic reduction device including a selective reducing / catalyst using bs vanadium; a first jetting section provided upstream of the first selective catalytic reduction = device in the exhaust pipe, the first jetting section being configured to jet reducing © agent; and ol a second selective catalytic reduction device provided downstream of the first selective catalytic reduction device in the exhaust pipe, the second selective catalytic reduction device including a selective reducing catalyst using copper.
2. The exhaust gas cleaning system according to claim 1 further comprising: a second jetting section provided between the first selective catalytic reduction device and the second selective catalytic reduction device in the exhaust pipe, the second jetting section being configured to jet reducing agent; wherein the second jetting section is controlled such that a jetting amount of the reducing agent is greater in a case where a NOx concentration of exhaust gas passing between the first selective catalytic reduction device and the second selective catalytic reduction device is equal to or greater than a predetermined concentration than in a case where the NOx concentration is smaller than the predetermined concentration.
3. The exhaust gas cleaning system according to claim 2, wherein the second jetting section is controlled to jet the reducing agent when the NOx concentration is equal to or greater than the predetermined concentration, and not to jet < the reducing agent when the NOx concentration is smaller than the predetermined pegatrs © concentration. prolate
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2017156578A JP2019035360A (en) | 2017-08-14 | 2017-08-14 | Exhaust emission control system |
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| Publication Number | Publication Date |
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| PH12018000215A1 true PH12018000215A1 (en) | 2019-03-04 |
| PH12018000215B1 PH12018000215B1 (en) | 2019-03-04 |
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| PH12018000215A PH12018000215B1 (en) | 2017-08-14 | 2018-08-10 | Exhaust gas cleaning system |
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| JP (1) | JP2019035360A (en) |
| CN (1) | CN109386364B (en) |
| PH (1) | PH12018000215B1 (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130061576A1 (en) * | 2011-09-09 | 2013-03-14 | GM Global Technology Operations LLC | Selective catalytic reduction (scr) device control system |
| US20150096287A1 (en) * | 2013-10-03 | 2015-04-09 | Baohua Qi | Multi-stage SCR Control and Diagnostic System |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000303826A (en) * | 1999-04-16 | 2000-10-31 | Isuzu Motors Ltd | Exhaust emission control device for diesel engine |
| EP1286027A1 (en) * | 2001-08-14 | 2003-02-26 | Siemens Aktiengesellschaft | Catalyst system, its use and method of its operation |
| DE10308288B4 (en) * | 2003-02-26 | 2006-09-28 | Umicore Ag & Co. Kg | Process for the removal of nitrogen oxides from the exhaust gas of a lean-burned internal combustion engine and exhaust gas purification system for this purpose |
| JP2006057578A (en) * | 2004-08-23 | 2006-03-02 | Hino Motors Ltd | Exhaust emission control device |
| EP2116293B1 (en) * | 2008-04-11 | 2010-03-17 | Umicore AG & Co. KG | Exhaust gas cleaning system for treating motor exhaust gases with an SCR catalytic converter |
| RU2524165C2 (en) * | 2009-02-20 | 2014-07-27 | Хальдор Топсеэ А/С | Diesel exhaust gas cleaning |
| US20110064632A1 (en) * | 2009-09-14 | 2011-03-17 | Ford Global Technologies, Llc | Staged Catalyst System and Method of Using the Same |
| US10113462B2 (en) * | 2015-04-24 | 2018-10-30 | Cummins Inc. | Advanced exhaust aftertreatment system architecture |
| SE539133C2 (en) * | 2015-08-27 | 2017-04-11 | Scania Cv Ab | Exhaust gas treatment system and method for treating an exhaust gas stream |
| US9616385B1 (en) * | 2015-09-30 | 2017-04-11 | Deere & Company | System and method for regulating exhaust emissions |
-
2017
- 2017-08-14 JP JP2017156578A patent/JP2019035360A/en active Pending
-
2018
- 2018-08-06 CN CN201810885545.3A patent/CN109386364B/en active Active
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130061576A1 (en) * | 2011-09-09 | 2013-03-14 | GM Global Technology Operations LLC | Selective catalytic reduction (scr) device control system |
| US20150096287A1 (en) * | 2013-10-03 | 2015-04-09 | Baohua Qi | Multi-stage SCR Control and Diagnostic System |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109386364A (en) | 2019-02-26 |
| CN109386364B (en) | 2021-08-13 |
| JP2019035360A (en) | 2019-03-07 |
| PH12018000215B1 (en) | 2019-03-04 |
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