US20100037596A1 - Exhaust purification device of compression ignition type internal combustion engine - Google Patents
Exhaust purification device of compression ignition type internal combustion engine Download PDFInfo
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- US20100037596A1 US20100037596A1 US12/312,785 US31278508A US2010037596A1 US 20100037596 A1 US20100037596 A1 US 20100037596A1 US 31278508 A US31278508 A US 31278508A US 2010037596 A1 US2010037596 A1 US 2010037596A1
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- reducing catalyst
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
- F01N3/0814—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
- B01D53/9404—Removing only nitrogen compounds
- B01D53/9409—Nitrogen oxides
- B01D53/9413—Processes characterised by a specific catalyst
- B01D53/9418—Processes characterised by a specific catalyst for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a lean exhaust gas
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
- B01D53/9459—Removing one or more of nitrogen oxides, carbon monoxide, or hydrocarbons by multiple successive catalytic functions; systems with more than one different function, e.g. zone coated catalysts
- B01D53/9477—Removing one or more of nitrogen oxides, carbon monoxide, or hydrocarbons by multiple successive catalytic functions; systems with more than one different function, e.g. zone coated catalysts with catalysts positioned on separate bricks, e.g. exhaust systems
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
- B01D53/9495—Controlling the catalytic process
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/96—Regeneration, reactivation or recycling of reactants
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
- F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- 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
- F01N3/105—General auxiliary catalysts, e.g. upstream or downstream of the main catalyst
- F01N3/106—Auxiliary oxidation catalysts
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/18—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
- F01N3/2006—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating
- F01N3/2033—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating using a fuel burner or introducing fuel into exhaust duct
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/18—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]
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N9/00—Electrical control of exhaust gas treating apparatus
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2251/00—Reactants
- B01D2251/20—Reductants
- B01D2251/206—Ammonium compounds
- B01D2251/2067—Urea
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2251/00—Reactants
- B01D2251/20—Reductants
- B01D2251/21—Organic compounds not provided for in groups B01D2251/206 or B01D2251/208
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/10—Noble metals or compounds thereof
- B01D2255/102—Platinum group metals
- B01D2255/1021—Platinum
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/20—Metals or compounds thereof
- B01D2255/207—Transition metals
- B01D2255/20738—Iron
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2255/00—Catalysts
- B01D2255/50—Zeolites
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2258/00—Sources of waste gases
- B01D2258/01—Engine exhaust gases
- B01D2258/012—Diesel engines and lean burn gasoline engines
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
- F01N2560/06—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being a temperature sensor
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
- F01N2560/14—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics having more than one sensor of one kind
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2610/00—Adding substances to exhaust gases
- F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2610/00—Adding substances to exhaust gases
- F01N2610/03—Adding substances to exhaust gases the substance being hydrocarbons, e.g. engine fuel
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- 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
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- 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
Definitions
- the present invention relates to an exhaust purification device of a compression ignition type internal combustion engine.
- Known in the art is an internal combustion engine arranging an NO x selective reducing catalyst in an engine exhaust passage, arranging an oxidation catalyst in the engine exhaust passage upstream of the NO x selective reducing catalyst, feeding urea to the NO x selective reducing catalyst, and using the ammonia produced from the urea to selectively reduce the NO x contained in the exhaust gas (for example, see Japanese Patent Publication (A) No. 2005-23921).
- the NO x selective reducing catalyst adsorbs ammonia and the adsorbed ammonia reacts with the NO x contained in the exhaust gas whereby the NO x is reduced.
- An object of the present invention is to provide an exhaust purification device of a compression ignition type internal combustion engine capable of obtaining a good NO x purification rate at engine startup.
- an exhaust purification device of a compression ignition type internal combustion engine arranging an NO x selective reducing catalyst in an engine exhaust passage, arranging an oxidation catalyst in the engine exhaust passage upstream of the NO x selective reducing catalyst, feeding urea to the NO x selective reducing catalyst, and using an ammonia produced from the urea to selectively reduce NO x contained in the exhaust gas, wherein HC is fed to the oxidation catalyst at the time of engine startup to raise a temperature of the NO x selective reducing catalyst with a heat of oxidation reaction of HC, and at this time, the temperature of the NO x selective reducing catalyst is increased to a HC desorption temperature range where HC is desorbed from the NO x selective reducing catalyst.
- Increasing the temperature of the NO x selective reducing catalyst to the HC desorption temperature range eliminates the HC poisoning of the NO x selective reducing catalyst and thereby gives a good NO x purification rate.
- FIG. 1 is an overview of a compression ignition type internal combustion engine
- FIG. 2 is an overview showing another embodiment of the compression ignition type internal combustion engine
- FIG. 3 is a view showing an oxidation rate and desorption rate
- FIG. 4 is a time chart showing warm-up control
- FIG. 5 is a flow chart for performing the warm-up control.
- FIG. 1 shows an overview of a compression ignition type internal combustion engine.
- 1 indicates an engine body, 2 a combustion chamber of a cylinder, 3 an electronic control type fuel injector for injecting fuel into each combustion chamber 2 , 4 an intake manifold, and 5 an exhaust manifold.
- the intake manifold 4 is connected through an intake duct 6 to the outlet of a compressor 7 a of an exhaust turbocharger 7 , while the inlet of the compressor 7 a is connected through an intake air amount detector 8 to an air cleaner 9 .
- a throttle valve 10 driven by a step motor is arranged inside the intake duct 6 .
- a cooling device 11 for cooling the intake air flowing through the inside of the intake duct 6 is arranged. In the embodiment shown in FIG. 1 , the engine cooling water is guided to the cooling device 11 where the engine cooling water cools the intake air.
- the exhaust manifold 5 is connected to the inlet of an exhaust turbine 7 b of the exhaust turbocharger 7 , while the outlet of the exhaust turbine 7 b is connected to the inlet of an oxidation catalyst 12 .
- a particulate filter 13 is arranged adjacent to the oxidation catalyst 12 for collecting particulate matter contained in the exhaust gas, while the outlet of this particulate filter 13 is connected through an exhaust pipe 14 to the inlet of an NO x selective reducing catalyst 15 .
- the outlet of this NO x selective reducing catalyst 15 is connected to an oxidation catalyst 16 .
- an aqueous urea solution feed valve 17 is arranged inside an exhaust pipe 14 upstream of the NO x selective reducing catalyst 15 .
- This aqueous urea solution feed valve 17 is connected through a feed pipe 18 and a feed pump 19 to an aqueous urea solution tank 20 .
- the aqueous urea solution stored inside the aqueous urea solution tank 20 is injected by the feed pump 19 into the exhaust gas flowing within the exhaust pipe 14 from the aqueous urea solution feed valve 17 , while the ammonia ((NH 2 ) 2 CO+H 2 O 2 NH 3 +CO 2 ) generated from urea causes the NO x contained in the exhaust gas to be reduced in the NO x selective reducing catalyst 15 .
- the exhaust manifold 5 and the intake manifold 4 are connected to each other through an exhaust gas recirculation (hereinafter referred to as the “EGR”) passage 21 .
- EGR exhaust gas recirculation
- an electronic control type EGR control valve 22 Inside the EGR passage 21 is arranged an electronic control type EGR control valve 22 .
- a cooling device 23 for cooling the EGR gas flowing through the inside of the EGR passage 21 .
- the engine cooling water is guided through the cooling device 23 , where the engine cooling water is used to cool the EGR gas.
- each fuel injector 3 is connected through a fuel feed pipe 24 to a common rail 25 .
- This common rail 25 is connected through an electronically controlled variable discharge fuel pump 26 to a fuel tank 27 .
- the fuel stored in the fuel tank 27 is fed by the fuel pump 26 into the common rail 25 , and the fuel fed to the inside of the common rail 25 is fed through each fuel pipe 24 to the fuel injectors 3 .
- an HC feed valve 28 for feeding hydrocarbons, i.e., HC into the exhaust manifold 5 is arranged in the exhaust manifold 5 .
- this HC is comprised of diesel oil.
- An electronic control unit 30 is comprised of a digital computer provided with a ROM (read only memory) 32 , RAM (random access memory) 33 , CPU (microprocessor) 34 , input port 35 , and output port 36 all connected to each other by a bi-directional bus 31 .
- a temperature sensor 45 for detecting the bed temperature of the oxidation catalyst 12 is attached to the oxidation catalyst 12
- a temperature sensor 46 for detecting the bed temperature of the NO x selective reducing catalyst 15 is attached to the NO x selective reducing catalyst 15 .
- the output signals of these temperature sensors 45 and 46 and intake air amount detector 8 are input through corresponding AD converters 37 into the input port 35 .
- the accelerator pedal 40 has a load sensor 41 generating an output voltage proportional to the amount of depression L of the accelerator pedal 40 connected to it.
- the output voltage of the load sensor 41 is input through a corresponding AD converter 37 to the input port 35 .
- the input port 35 has a crank angle sensor 42 generating an output pulse each time the crank shaft rotates by for example 15° C. connected to it.
- the output port 36 is connected through corresponding drive circuits 38 to the fuel injectors 3 , throttle valve 10 drive step motor, aqueous urea solution feed valve 17 , feed pump 19 , EGR control valve 22 , fuel pump 26 , and HC feed valve 28 .
- the oxidation catalyst 12 for example, carries a precious metal catalyst such as platinum.
- This oxidation catalyst 12 performs the action of converting the NO contained in the exhaust gas to NO 2 and the action of oxidizing the HC contained in the exhaust gas. That is, NO 2 has stronger oxidation properties than NO. Therefore, if NO is converted to NO 2 , the oxidation reaction of the particulate matter trapped on the particulate filter 13 is promoted. Further, the reduction action by the ammonia at the NO x selective reducing catalyst 15 is promoted.
- the NO x selective reducing catalyst 15 as explained above, if HC is deposited, the adsorption amount of the ammonia will decrease, therefore the NO x purification rate will fall. Accordingly, by using the oxidation catalyst 12 to oxidize the HC, the deposition of HC at the NO x selective reducing catalyst 15 , that is, the HC poisoning of the NO x selective reducing catalyst 15 , is avoided.
- a particulate filter not carrying a catalyst may be used.
- a particulate filter carrying, for example, a precious metal catalyst such as platinum may be used.
- the NOX selective reducing catalyst 15 is comprised of an ammonia adsorption type Fe zeolite having a high NO x purification rate at low temperatures.
- the oxidation catalyst 16 carries, for example, a precious metal catalyst comprised of platinum, and this oxidation catalyst 16 performs an action of oxidizing ammonia leaked from the NO x selective reducing catalyst 15 .
- FIG. 2 shows another embodiment of the compression ignition type internal combustion engine.
- the particulate filter 13 is arranged downstream of the oxidation catalyst 16 , accordingly, in this embodiment, the outlet of the oxidation catalyst 12 is coupled through the exhaust pipe 14 to the inlet of the NO x selective reducing catalyst 15 .
- HC is fed to the oxidation catalyst 12 at the time of engine startup so as to raise the temperature of the NO x selective reducing catalyst 15 with the heat of oxidation reaction of HC.
- the feed of the HC may be performed, for example, by injecting fuel into the combustion chamber 2 during the exhaust stroke or by feeding HC into the engine exhaust passage.
- the HC is fed by injecting diesel fuel from the HC feed valve 28 .
- FIG. 3(A) shows the relation between the bed temperature T 0 of the oxidation catalyst 12 and the oxidation rate M 0 (g/sec) of the HC, that is, the amount of HC able to be oxidized per unit time.
- the oxidation catalyst 12 upon activation of the oxidation catalyst 12 , when the amount of HC flowing into the oxidation catalyst 12 per unit time is lower than the oxidation rate M 0 determined from the bed temperature T 0 of the oxidation catalyst 12 , all of the inflowing HC is oxidized in the oxidation catalyst 12 , and when the amount of HC flowing into the oxidation catalyst 12 per unit time is greater than the oxidation rate M 0 determined from the bed temperature of the oxidation catalyst 12 , the amount by which the HC exceeds the oxidation rate M 0 will slip the oxidation catalyst 12 .
- the HC slipping the oxidation catalyst 12 will flow into the NO x selective reducing catalyst 15 and deposit on the NO x selective reducing catalyst 15 .
- this deposited HC may be desorbed from the NO x selective reducing catalyst 15 by raising the temperature of the NO x selective reducing catalyst 15 . This will be explained while referring to FIG. 3(B) .
- FIG. 3(B) shows the relation between the bed temperature Tn of the NO x selective reducing catalyst 15 and the desorption rate Md(g/sec) of the HC, that is, the amount of HC desorbed from the NO x selective reducing catalyst 15 per unit time.
- the desorption rate Md rises.
- the approximately 350° C. indicated by TF becomes the desorption start temperature. Accordingly, by raising the bed temperature Tn of the NO x selective reducing catalyst 15 to the desorption start temperature TF or above, HC can be desorbed from the NO x selective reducing catalyst 15 .
- a large amount of HC may be fed from the HC feed valve 28 .
- HC will slip the oxidation catalyst 12 and the NO x selective reducing catalyst 15 will be poisoned by HC.
- raising the temperature of the NO x selective reducing catalyst 15 to an HC desorption temperature range greater than the desorption start temperature TF HC poisoning can be eliminated. Accordingly, in the present invention, the temperature of the NO x selective reducing catalyst 15 at the time of engine startup will be raised to the HC desorption temperature range where HC is desorbed from the NO x selective reducing catalyst 15 .
- HC feed from the HC feed valve 28 will begin. Fluctuation in the HC feed amount is indicated as G I . That is, the HC feed amount G I is reduced little by little so that the bed temperature T 0 of the oxidation catalyst 12 approaches the target temperature smoothly.
- the HC feed amount G I is large, so a large amount of HC will slip the oxidation catalyst 12 , but the more the bed temperature T 0 of the oxidation catalyst 12 rises, the more the HC amount oxidized in the oxidation catalyst 12 , so, as shown in FIG. 4 , the slipped HC amount W will gradually decrease along with the elapse of time.
- the NO x selective reducing catalyst 15 is heated by the exhaust gas raised in temperature in the oxidation catalyst 12 , so, as shown by the solid line in FIG. 4 , its temperature will rise slower than the oxidation catalyst 12 .
- the bed temperature Tn of the NO x selective reducing catalyst 15 is lower than the desorption start temperature TF, the slipped HC amount W will be added to the HC deposition amount ⁇ HC, whereby the deposition amount ⁇ HC will gradually increase.
- the bed temperature Tn of the NO x selective reducing catalyst 15 exceeds the desorption start temperature TF, the desorption action of the HC from the NO x selective reducing catalyst 15 will begin, whereby the HC deposition amount ⁇ HC will gradually decrease.
- the feed of HC is stopped. That is, in this embodiment, the HC amount deposited on the NO x selective reducing catalyst 15 is calculated and the feed of HC is stopped when the calculated HC amount ⁇ HC becomes less than the predetermined set value HCX.
- the change of the bed temperature Tn of the NO x selective reducing catalyst 15 shown by the broken line in FIG. 4 shows the change at the time of conventional temperature raising control.
- T f the convergence temperature which the temperature of the NO x selective reducing catalyst 15 ultimately converges to.
- This convergence temperature T f is approximately 200° C. to 250° C.
- the bed temperature Tn of the NO x selective reducing catalyst 15 is changed to smoothly increase towards the convergence temperature T f .
- the bed temperature Tn of the NO x selective reducing catalyst 15 at the time of engine startup is raised to a temperature of 350° C. at least 100° C. higher than the convergence temperature T f .
- step 50 the exhaust HC amount G 0 is calculated.
- the exhaust HC amount G 0 changing based on the operation state of the engine is stored in advance in the ROM 32 .
- step 51 it is judged whether the bed temperature T 0 of the oxidation catalyst 12 exceeds the activation temperature TX.
- T 0 ⁇ TF the routine proceeds to step 52 , where the slipped amount W is made the exhaust HC amount G 0 , then the routine proceeds to step 59 .
- step 53 the routine proceeds to step 53 , where the HC feed amount G I is calculated.
- step 54 feed control for the HC from the HC feed valve 28 is performed.
- step 55 the oxidation rate M 0 , as shown in FIG. 3(A) , is calculated based on the bed temperature T 0 of the oxidation catalyst 12 .
- step 56 it is judged whether the oxidation rate M 0 is larger than the sum (G 0 +G 1 ) of the exhaust HC amount G 0 and the fed HC amount G 1 .
- step 57 When M 0 ⁇ G 0 +G 1 , the routine proceeds to step 57 , where the slipped amount W is made 0, then the routine proceeds to step 59 . As opposed to this, when the M 0 ⁇ G 0 +G 1 , the routine proceeds to step 58 , where the slipped amount is made G 0 +G 1 ⁇ M 0 , then the routine proceeds to step 59 .
- the desorption rate Md shown in FIG. 3(B) is calculated based on the bed temperature Tn of the NO x selective reducing catalyst 15 .
- the slipped amount W is added to the HC deposition amount ⁇ HC and the desorption rate Md is subtracted from the HC deposition amount ⁇ HC to calculate the HC deposition amount ⁇ HC.
Abstract
In an internal combustion engine, an NOx selective reducing catalyst (15) is arranged in an engine exhaust passage and an oxidation catalyst (12) is arranged in the engine exhaust passage upstream of the NOx selective reducing catalyst (15). At the time of engine startup, HC is fed from a HC feed valve (28) to the oxidation catalyst (12), thereby raising the temperature of the NOx selective reducing catalyst(15) by the heat of the oxidation reaction of HC. At this time, the temperature of the NOx selective reducing catalyst (15) is raised to a HC desorption range where HC is desorbed from the NOx selective reducing catalyst (15).
Description
- The present invention relates to an exhaust purification device of a compression ignition type internal combustion engine.
- Known in the art is an internal combustion engine arranging an NOx selective reducing catalyst in an engine exhaust passage, arranging an oxidation catalyst in the engine exhaust passage upstream of the NOx selective reducing catalyst, feeding urea to the NOx selective reducing catalyst, and using the ammonia produced from the urea to selectively reduce the NOx contained in the exhaust gas (for example, see Japanese Patent Publication (A) No. 2005-23921). In this internal combustion engine, the NOx selective reducing catalyst adsorbs ammonia and the adsorbed ammonia reacts with the NOx contained in the exhaust gas whereby the NOx is reduced.
- In this internal combustion engine, however, when HC is fed into the oxidation catalyst at engine startup and the heat of oxidation reaction of the HC raises the temperature of the NOx selective reducing catalyst, if a large amount of HC is fed to warm up the NOx selective reducing catalyst early, HC unable to be completely oxidized in the oxidation catalyst will flow into the NOx selective reducing catalyst and deposit on the NOx selective reducing catalyst. In this regard, the problem arises that if HC deposits on the NOx selective reducing catalyst, the NOx selective reducing catalyst will become unable to adsorb ammonia and thereby the NOx purification rate will fall.
- As opposed to this, if reducing the amount of HC so as to keep HC from adhering to the NOx selective reducing catalyst, that is, to prevent the NOx selective reducing catalyst from being poisoned by HC, time will be needed for the NOx selective reducing catalyst to rise and therefore, in this case as well, the problem arises that the NOx purification rate will fall.
- An object of the present invention is to provide an exhaust purification device of a compression ignition type internal combustion engine capable of obtaining a good NOx purification rate at engine startup.
- According to the present invention, there is provided an exhaust purification device of a compression ignition type internal combustion engine arranging an NOx selective reducing catalyst in an engine exhaust passage, arranging an oxidation catalyst in the engine exhaust passage upstream of the NOx selective reducing catalyst, feeding urea to the NOx selective reducing catalyst, and using an ammonia produced from the urea to selectively reduce NOx contained in the exhaust gas, wherein HC is fed to the oxidation catalyst at the time of engine startup to raise a temperature of the NOx selective reducing catalyst with a heat of oxidation reaction of HC, and at this time, the temperature of the NOx selective reducing catalyst is increased to a HC desorption temperature range where HC is desorbed from the NOx selective reducing catalyst.
- Increasing the temperature of the NOx selective reducing catalyst to the HC desorption temperature range eliminates the HC poisoning of the NOx selective reducing catalyst and thereby gives a good NOx purification rate.
-
FIG. 1 is an overview of a compression ignition type internal combustion engine, -
FIG. 2 is an overview showing another embodiment of the compression ignition type internal combustion engine, -
FIG. 3 is a view showing an oxidation rate and desorption rate, -
FIG. 4 is a time chart showing warm-up control, and -
FIG. 5 is a flow chart for performing the warm-up control. -
FIG. 1 shows an overview of a compression ignition type internal combustion engine. - Referring to
FIG. 1 , 1 indicates an engine body, 2 a combustion chamber of a cylinder, 3 an electronic control type fuel injector for injecting fuel into eachcombustion chamber 2, 4 an intake manifold, and 5 an exhaust manifold. Theintake manifold 4 is connected through anintake duct 6 to the outlet of acompressor 7 a of anexhaust turbocharger 7, while the inlet of thecompressor 7 a is connected through an intakeair amount detector 8 to anair cleaner 9. Inside theintake duct 6, athrottle valve 10 driven by a step motor is arranged. Further, around theintake duct 6, acooling device 11 for cooling the intake air flowing through the inside of theintake duct 6 is arranged. In the embodiment shown inFIG. 1 , the engine cooling water is guided to thecooling device 11 where the engine cooling water cools the intake air. - On the other hand, the
exhaust manifold 5 is connected to the inlet of anexhaust turbine 7 b of theexhaust turbocharger 7, while the outlet of theexhaust turbine 7 b is connected to the inlet of anoxidation catalyst 12. Downstream of theoxidation catalyst 12, aparticulate filter 13 is arranged adjacent to theoxidation catalyst 12 for collecting particulate matter contained in the exhaust gas, while the outlet of thisparticulate filter 13 is connected through anexhaust pipe 14 to the inlet of an NOx selective reducingcatalyst 15. The outlet of this NOx selective reducingcatalyst 15 is connected to anoxidation catalyst 16. - Inside an
exhaust pipe 14 upstream of the NOx selective reducingcatalyst 15, an aqueous ureasolution feed valve 17 is arranged. This aqueous ureasolution feed valve 17 is connected through afeed pipe 18 and afeed pump 19 to an aqueousurea solution tank 20. The aqueous urea solution stored inside the aqueousurea solution tank 20 is injected by thefeed pump 19 into the exhaust gas flowing within theexhaust pipe 14 from the aqueous ureasolution feed valve 17, while the ammonia ((NH2)2CO+H2O2NH3+CO2) generated from urea causes the NOx contained in the exhaust gas to be reduced in the NOx selective reducingcatalyst 15. - The
exhaust manifold 5 and theintake manifold 4 are connected to each other through an exhaust gas recirculation (hereinafter referred to as the “EGR”)passage 21. Inside the EGRpassage 21 is arranged an electronic control typeEGR control valve 22. Further, around the EGRpassage 21 is arranged acooling device 23 for cooling the EGR gas flowing through the inside of the EGRpassage 21. In the embodiment shown inFIG. 1 , the engine cooling water is guided through thecooling device 23, where the engine cooling water is used to cool the EGR gas. On the other hand, eachfuel injector 3 is connected through afuel feed pipe 24 to acommon rail 25. Thiscommon rail 25 is connected through an electronically controlled variabledischarge fuel pump 26 to afuel tank 27. The fuel stored in thefuel tank 27 is fed by thefuel pump 26 into thecommon rail 25, and the fuel fed to the inside of thecommon rail 25 is fed through eachfuel pipe 24 to thefuel injectors 3. Furthermore, anHC feed valve 28 for feeding hydrocarbons, i.e., HC into theexhaust manifold 5 is arranged in theexhaust manifold 5. In the embodiment shown inFIG. 1 , this HC is comprised of diesel oil. - An
electronic control unit 30 is comprised of a digital computer provided with a ROM (read only memory) 32, RAM (random access memory) 33, CPU (microprocessor) 34,input port 35, andoutput port 36 all connected to each other by abi-directional bus 31. Atemperature sensor 45 for detecting the bed temperature of theoxidation catalyst 12 is attached to theoxidation catalyst 12, and atemperature sensor 46 for detecting the bed temperature of the NOx selective reducingcatalyst 15 is attached to the NOx selective reducingcatalyst 15. The output signals of thesetemperature sensors air amount detector 8 are input throughcorresponding AD converters 37 into theinput port 35. - On the other hand, the
accelerator pedal 40 has aload sensor 41 generating an output voltage proportional to the amount of depression L of theaccelerator pedal 40 connected to it. The output voltage of theload sensor 41 is input through acorresponding AD converter 37 to theinput port 35. Further, theinput port 35 has acrank angle sensor 42 generating an output pulse each time the crank shaft rotates by for example 15° C. connected to it. On the other hand, theoutput port 36 is connected throughcorresponding drive circuits 38 to thefuel injectors 3,throttle valve 10 drive step motor, aqueous ureasolution feed valve 17,feed pump 19,EGR control valve 22,fuel pump 26, andHC feed valve 28. - The
oxidation catalyst 12, for example, carries a precious metal catalyst such as platinum. Thisoxidation catalyst 12 performs the action of converting the NO contained in the exhaust gas to NO2 and the action of oxidizing the HC contained in the exhaust gas. That is, NO2 has stronger oxidation properties than NO. Therefore, if NO is converted to NO2, the oxidation reaction of the particulate matter trapped on theparticulate filter 13 is promoted. Further, the reduction action by the ammonia at the NOx selective reducingcatalyst 15 is promoted. On the other hand, at the NOx selective reducingcatalyst 15, as explained above, if HC is deposited, the adsorption amount of the ammonia will decrease, therefore the NOx purification rate will fall. Accordingly, by using theoxidation catalyst 12 to oxidize the HC, the deposition of HC at the NOx selective reducingcatalyst 15, that is, the HC poisoning of the NOx selective reducingcatalyst 15, is avoided. - As the
particulate filter 13, a particulate filter not carrying a catalyst may be used. For example, a particulate filter carrying, for example, a precious metal catalyst such as platinum may be used. On the other hand, the NOX selective reducingcatalyst 15 is comprised of an ammonia adsorption type Fe zeolite having a high NOx purification rate at low temperatures. Further, theoxidation catalyst 16 carries, for example, a precious metal catalyst comprised of platinum, and thisoxidation catalyst 16 performs an action of oxidizing ammonia leaked from the NOx selective reducingcatalyst 15. -
FIG. 2 shows another embodiment of the compression ignition type internal combustion engine. In this embodiment, theparticulate filter 13 is arranged downstream of theoxidation catalyst 16, accordingly, in this embodiment, the outlet of theoxidation catalyst 12 is coupled through theexhaust pipe 14 to the inlet of the NOx selective reducingcatalyst 15. - If the NOx selective reducing
catalyst 15 does not rise in temperature a certain degree, the selective reduction action of NOx will not be performed, that is, the catalyst will not be activated. Accordingly, it is necessary to activate the NOx selective reducingcatalyst 15 as soon as possible at engine startup. Here, in the present invention, HC is fed to theoxidation catalyst 12 at the time of engine startup so as to raise the temperature of the NOx selective reducingcatalyst 15 with the heat of oxidation reaction of HC. The feed of the HC may be performed, for example, by injecting fuel into the combustion chamber 2 during the exhaust stroke or by feeding HC into the engine exhaust passage. In the embodiments shown inFIG. 1 andFIG. 2 , the HC is fed by injecting diesel fuel from theHC feed valve 28. - However, it is not necessarily possible to oxidize all of the HC fed in the
oxidation catalyst 12 at the time of engine startup. This will be explained while referring toFIG. 3(A) .FIG. 3(A) shows the relation between the bed temperature T0 of theoxidation catalyst 12 and the oxidation rate M0(g/sec) of the HC, that is, the amount of HC able to be oxidized per unit time. - As is clear from
FIG. 3(A) , when the bed temperature T0 of theoxidation catalyst 12 is approximately 200° C. or below, that is, when theoxidation catalyst 12 is not activated, the oxidation rate M0 is zero. Accordingly, the HC flowing into theoxidation catalyst 12 at this time will slip theoxidation catalyst 12. On the other hand, upon activation of theoxidation catalyst 12, when the amount of HC flowing into theoxidation catalyst 12 per unit time is lower than the oxidation rate M0 determined from the bed temperature T0 of theoxidation catalyst 12, all of the inflowing HC is oxidized in theoxidation catalyst 12, and when the amount of HC flowing into theoxidation catalyst 12 per unit time is greater than the oxidation rate M0 determined from the bed temperature of theoxidation catalyst 12, the amount by which the HC exceeds the oxidation rate M0 will slip theoxidation catalyst 12. - The HC slipping the
oxidation catalyst 12 will flow into the NOx selective reducingcatalyst 15 and deposit on the NOx selective reducingcatalyst 15. However, this deposited HC may be desorbed from the NOx selective reducingcatalyst 15 by raising the temperature of the NOx selective reducingcatalyst 15. This will be explained while referring toFIG. 3(B) . -
FIG. 3(B) shows the relation between the bed temperature Tn of the NOx selective reducingcatalyst 15 and the desorption rate Md(g/sec) of the HC, that is, the amount of HC desorbed from the NOx selective reducingcatalyst 15 per unit time. As shown inFIG. 3(B) , when the bed temperature Tn of the NOx selective reducingcatalyst 15 exceeds approximately 350° C., the desorption rate Md rises. InFIG. 3(B) , the approximately 350° C. indicated by TF becomes the desorption start temperature. Accordingly, by raising the bed temperature Tn of the NOx selective reducingcatalyst 15 to the desorption start temperature TF or above, HC can be desorbed from the NOx selective reducingcatalyst 15. - To raise the temperature of the NOx selective reducing
catalyst 15 early, a large amount of HC may be fed from theHC feed valve 28. However, if feeding a large amount of HC, HC will slip theoxidation catalyst 12 and the NOx selective reducingcatalyst 15 will be poisoned by HC. However, if raising the temperature of the NOx selective reducingcatalyst 15 to an HC desorption temperature range greater than the desorption start temperature TF, HC poisoning can be eliminated. Accordingly, in the present invention, the temperature of the NOx selective reducingcatalyst 15 at the time of engine startup will be raised to the HC desorption temperature range where HC is desorbed from the NOx selective reducingcatalyst 15. - Next, the warm-up control of the NOx selective reducing
catalyst 15 according to the present invention will be explained while referring toFIG. 4 . - When the engine is started up, a large amount of unburned HC will be exhausted from the combustion chamber 2. Accordingly, as shown in
FIG. 4 , the amount G0 of HC exhausted from the combustion chamber 2 at the time of engine startup will temporarily become high. Normally, theoxidation catalyst 12 is not activated at this time, so this exhaust HC slips theoxidation catalyst 12. This slipped HC is deposited on the NOx selective reducingcatalyst 15. Accordingly, as is clear fromFIG. 4 , the slipped HC amount W is added to the NOx HC deposition amount ΣHC of the selective reducingcatalyst 15. - Next, when the bed temperature T0 of the
oxidation catalyst 12 exceeds the activation temperature TX, HC feed from theHC feed valve 28 will begin. Fluctuation in the HC feed amount is indicated as GI. That is, the HC feed amount GI is reduced little by little so that the bed temperature T0 of theoxidation catalyst 12 approaches the target temperature smoothly. The HC feed amount GI is large, so a large amount of HC will slip theoxidation catalyst 12, but the more the bed temperature T0 of theoxidation catalyst 12 rises, the more the HC amount oxidized in theoxidation catalyst 12, so, as shown inFIG. 4 , the slipped HC amount W will gradually decrease along with the elapse of time. - On the other hand, as the NOx selective reducing
catalyst 15 is heated by the exhaust gas raised in temperature in theoxidation catalyst 12, so, as shown by the solid line inFIG. 4 , its temperature will rise slower than theoxidation catalyst 12. When the bed temperature Tn of the NOx selective reducingcatalyst 15 is lower than the desorption start temperature TF, the slipped HC amount W will be added to the HC deposition amount ΣHC, whereby the deposition amount ΣHC will gradually increase. However, when the bed temperature Tn of the NOx selective reducingcatalyst 15 exceeds the desorption start temperature TF, the desorption action of the HC from the NOx selective reducingcatalyst 15 will begin, whereby the HC deposition amount ΣHC will gradually decrease. - Next, when the HC deposition amount ΣHC is less than the set value HCX, the feed of HC is stopped. That is, in this embodiment, the HC amount deposited on the NOx selective reducing
catalyst 15 is calculated and the feed of HC is stopped when the calculated HC amount ΣHC becomes less than the predetermined set value HCX. - Note that, the maximum temperature limit which the bed temperature T0 of the NOx selective reducing
catalyst 15 can be raised to, when considering heat deterioration, becomes approximately 650°. Accordingly, in the embodiment of the present invention, the temperature of the NOx selective reducingcatalyst 15 at the time of engine startup is increased within the range of 350° C. to 650° C. - On the other hand, the change of the bed temperature Tn of the NOx selective reducing
catalyst 15 shown by the broken line inFIG. 4 shows the change at the time of conventional temperature raising control. In the internal combustion engine, when idling operation is continued during the warm-up operation, there is a convergence temperature Tf which the temperature of the NOx selective reducingcatalyst 15 ultimately converges to. This convergence temperature Tf is approximately 200° C. to 250° C. In a conventional temperature raising control, the bed temperature Tn of the NOx selective reducingcatalyst 15, as shown by the broken line, is changed to smoothly increase towards the convergence temperature Tf. - As opposed to this, in the present invention, it is learned that the bed temperature Tn of the NOx selective reducing
catalyst 15 at the time of engine startup is raised to a temperature of 350° C. at least 100° C. higher than the convergence temperature Tf. - Next, the warm-up control routine shown in
FIG. 5 will be explained. Note that this control routine is executed by interruption every constant time period. - Referring to
FIG. 5 , first, atstep 50, the exhaust HC amount G0 is calculated. The exhaust HC amount G0 changing based on the operation state of the engine is stored in advance in theROM 32. Next, atstep 51, it is judged whether the bed temperature T0 of theoxidation catalyst 12 exceeds the activation temperature TX. When T0≦TF, the routine proceeds to step 52, where the slipped amount W is made the exhaust HC amount G0, then the routine proceeds to step 59. - As opposed to this, when T0>TX, the routine proceeds to step 53, where the HC feed amount GI is calculated. Next, at
step 54, feed control for the HC from theHC feed valve 28 is performed. Next, atstep 55, the oxidation rate M0, as shown inFIG. 3(A) , is calculated based on the bed temperature T0 of theoxidation catalyst 12. Next, atstep 56, it is judged whether the oxidation rate M0 is larger than the sum (G0+G1) of the exhaust HC amount G0 and the fed HC amount G1. When M0≧G0+G1, the routine proceeds to step 57, where the slipped amount W is made 0, then the routine proceeds to step 59. As opposed to this, when the M0<G0+G1, the routine proceeds to step 58, where the slipped amount is made G0+G1−M0, then the routine proceeds to step 59. - At
step 59, the desorption rate Md shown inFIG. 3(B) is calculated based on the bed temperature Tn of the NOx selective reducingcatalyst 15. Next, atstep 60, the slipped amount W is added to the HC deposition amount ΣHC and the desorption rate Md is subtracted from the HC deposition amount ΣHC to calculate the HC deposition amount ΣHC. Next, atstep 61, it is judged whether the HC deposition amount ΣHC is still decreasing. When it is still decreasing, the routine proceeds to step 62, where it is judged whether the HC deposition amount ΣHC has become lower than the set value HCX. When ΣHC<HCX, the routine proceeds to step 63, where the feed of HC is stopped. -
- 4 . . . intake manifold
- 5 . . . exhaust manifold
- 7 . . . exhaust turbocharger
- 12, 16 . . . oxidation catalyst
- 13 . . . particulate filter
- 15 . . . NOX selective reducing catalyst
- 17 . . . aqueous urea feed valve
- 28 . . . HC feed valve
Claims (4)
1-4. (canceled)
5. An exhaust purification device of a compression ignition type internal combustion engine arranging an NOx selective reducing catalyst in an engine exhaust passage, arranging an oxidation catalyst in the engine exhaust passage upstream of the NOx selective reducing catalyst, feeding urea to the NOx selective reducing catalyst, and using an ammonia produced from the urea to selectively reduce NOx contained in an exhaust gas, wherein HC is fed into the oxidation catalyst at the time of engine startup to raise a temperature of the NOx selective reducing catalyst with a heat of oxidation reaction of HC, and at this time, the temperature of the NOx selective reducing catalyst is increased to a HC desorption temperature range where HC is desorbed from the NOx selective reducing catalyst, an amount of HC deposited at the NOx selective reducing catalyst being calculated, and the feed of HC being stopped when a calculated HC amount becomes less than a predetermined set value.
6. The exhaust purification device of the compression ignition type internal combustion engine as claimed in claim 5 , wherein at the time of raising the temperature of the NOx selective reducing catalyst, the temperature of the NOx selective reducing catalyst is increased to a range within 350° C. to 650° C.
7. The exhaust purification device of the compression ignition type internal combustion engine as claimed in claim 5 , wherein there is a convergence temperature at which the temperature of the NOx selective reducing catalyst ultimately converges when an idling operation is continued during warm-up operation and wherein the temperature of the NOx selective reducing catalyst at the time of raising the temperature of the NOx selective reducing catalyst is increased to a temperature at least 100° C. higher than the convergence temperature.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
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JP2007070020A JP4702310B2 (en) | 2007-03-19 | 2007-03-19 | Exhaust gas purification device for compression ignition type internal combustion engine |
JP2007-070020 | 2007-03-19 | ||
PCT/JP2008/055615 WO2008114885A1 (en) | 2007-03-19 | 2008-03-18 | Exhaust purification apparatus for compression-ignition internal combustion engine |
Publications (1)
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US20100037596A1 true US20100037596A1 (en) | 2010-02-18 |
Family
ID=39765983
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US12/312,785 Abandoned US20100037596A1 (en) | 2007-03-19 | 2008-03-18 | Exhaust purification device of compression ignition type internal combustion engine |
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US (1) | US20100037596A1 (en) |
EP (1) | EP2123875B1 (en) |
JP (1) | JP4702310B2 (en) |
CN (1) | CN101600862B (en) |
AT (1) | ATE555282T1 (en) |
WO (1) | WO2008114885A1 (en) |
Cited By (7)
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US20120036839A1 (en) * | 2010-08-10 | 2012-02-16 | Gm Global Technology Operations, Inc. | Vehicle oxidation catalyst efficiency model for adaptive control and diagnostics |
US8806851B2 (en) | 2007-09-28 | 2014-08-19 | Daimler Ag | Method for reducing emission of nitrogen oxide in a motor vehicle having a lean burning internal combustion engine |
US9212586B2 (en) | 2012-05-29 | 2015-12-15 | Toyota Jidosha Kabushiki Kaisha | Exhaust gas purification apparatus for internal combustion engine |
US20160290204A1 (en) * | 2013-03-22 | 2016-10-06 | Toyota Jidosha Kabushiki Kaisha | Exhaust Gas Purification Apparatus for Internal Combustion Engine |
US9776134B2 (en) | 2012-11-29 | 2017-10-03 | Toyota Jidosha Kabushiki Kaisha | Exhaust purification system of internal combustion engine |
US20180216510A1 (en) * | 2017-01-30 | 2018-08-02 | Ford Global Technologies, Llc | Exhaust gas aftertreatment |
CN114607490A (en) * | 2022-03-17 | 2022-06-10 | 潍柴动力股份有限公司 | Engine mode adjusting method and device, electronic equipment and storage medium |
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JP5615502B2 (en) * | 2009-02-24 | 2014-10-29 | バブコック日立株式会社 | Denitration catalyst protection method and denitration catalyst protection device |
US8904760B2 (en) * | 2009-06-17 | 2014-12-09 | GM Global Technology Operations LLC | Exhaust gas treatment system including an HC-SCR and two-way catalyst and method of using the same |
JP6129215B2 (en) * | 2012-03-02 | 2017-05-17 | ハルドール・トプサー・アクチエゼルスカベット | Method and system for removing harmful compounds from engine exhaust |
US9810124B2 (en) * | 2013-04-05 | 2017-11-07 | Toyota Jidosha Kabushiki Kaisha | Exhaust gas purification system of internal combustion engine |
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- 2008-03-18 US US12/312,785 patent/US20100037596A1/en not_active Abandoned
- 2008-03-18 EP EP08722814A patent/EP2123875B1/en not_active Not-in-force
- 2008-03-18 WO PCT/JP2008/055615 patent/WO2008114885A1/en active Application Filing
- 2008-03-18 CN CN2008800039860A patent/CN101600862B/en not_active Expired - Fee Related
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US6089015A (en) * | 1997-05-21 | 2000-07-18 | Degussa-Huls Aktiengesellschaft | Method of purifying a lean exhaust gas and catalytic system therefor |
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Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
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US8806851B2 (en) | 2007-09-28 | 2014-08-19 | Daimler Ag | Method for reducing emission of nitrogen oxide in a motor vehicle having a lean burning internal combustion engine |
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US9212586B2 (en) | 2012-05-29 | 2015-12-15 | Toyota Jidosha Kabushiki Kaisha | Exhaust gas purification apparatus for internal combustion engine |
US9776134B2 (en) | 2012-11-29 | 2017-10-03 | Toyota Jidosha Kabushiki Kaisha | Exhaust purification system of internal combustion engine |
US20160290204A1 (en) * | 2013-03-22 | 2016-10-06 | Toyota Jidosha Kabushiki Kaisha | Exhaust Gas Purification Apparatus for Internal Combustion Engine |
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US20180216510A1 (en) * | 2017-01-30 | 2018-08-02 | Ford Global Technologies, Llc | Exhaust gas aftertreatment |
US10690029B2 (en) * | 2017-01-30 | 2020-06-23 | Ford Global Technologies, Llc | System and method for exhaust gas aftertreatment with lean NOx trap and exhaust gas recirculation |
CN114607490A (en) * | 2022-03-17 | 2022-06-10 | 潍柴动力股份有限公司 | Engine mode adjusting method and device, electronic equipment and storage medium |
Also Published As
Publication number | Publication date |
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JP2008231966A (en) | 2008-10-02 |
EP2123875A4 (en) | 2011-05-11 |
ATE555282T1 (en) | 2012-05-15 |
CN101600862B (en) | 2013-01-02 |
CN101600862A (en) | 2009-12-09 |
EP2123875B1 (en) | 2012-04-25 |
WO2008114885A1 (en) | 2008-09-25 |
JP4702310B2 (en) | 2011-06-15 |
EP2123875A1 (en) | 2009-11-25 |
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