WO2008001950A1 - Purificateur de gaz d'échappement pour moteur à combustion interne - Google Patents
Purificateur de gaz d'échappement pour moteur à combustion interne Download PDFInfo
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- WO2008001950A1 WO2008001950A1 PCT/JP2007/063508 JP2007063508W WO2008001950A1 WO 2008001950 A1 WO2008001950 A1 WO 2008001950A1 JP 2007063508 W JP2007063508 W JP 2007063508W WO 2008001950 A1 WO2008001950 A1 WO 2008001950A1
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- exhaust gas
- supply
- sox
- temperature
- release
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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
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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
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/90—Injecting reactants
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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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- 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
- F01N3/0807—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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- 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
- F01N3/0828—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents characterised by the absorbed or adsorbed substances
- F01N3/0842—Nitrogen oxides
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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
- F01N3/0828—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents characterised by the absorbed or adsorbed substances
- F01N3/085—Sulfur or sulfur oxides
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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
- F01N3/0871—Regulation of absorbents or adsorbents, e.g. purging
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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
- F01N3/0871—Regulation of absorbents or adsorbents, e.g. purging
- F01N3/0885—Regeneration of deteriorated absorbents or adsorbents, e.g. desulfurization of NOx traps
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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
- F01N9/00—Electrical control of exhaust gas treating apparatus
- F01N9/002—Electrical control of exhaust gas treating apparatus of filter regeneration, e.g. detection of clogging
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/021—Introducing corrections for particular conditions exterior to the engine
- F02D41/0235—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
- F02D41/027—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus
- F02D41/0285—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus the exhaust gas treating apparatus being a SOx trap or adsorbent
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/30—Controlling fuel injection
- F02D41/38—Controlling fuel injection of the high pressure type
- F02D41/40—Controlling fuel injection of the high pressure type with means for controlling injection timing or duration
- F02D41/402—Multiple injections
- F02D41/405—Multiple injections with post injections
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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
- B01D2251/208—Hydrocarbons
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/30—Sulfur compounds
- B01D2257/302—Sulfur oxides
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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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- 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
- F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
- F01N2900/06—Parameters used for exhaust control or diagnosing
- F01N2900/16—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust apparatus, e.g. particulate filter or catalyst
- F01N2900/1612—SOx amount trapped in catalyst
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B37/00—Engines characterised by provision of pumps driven at least for part of the time by exhaust
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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
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
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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 emission control device for an internal combustion engine.
- Japanese Patent Application Laid-Open No. Hei 6 1 7 3 6 5 2 discloses an exhaust gas purification apparatus for an internal combustion engine provided with an NO X absorbent for absorbing NO X (nitrogen oxide) in exhaust gas in an exhaust passage.
- the exhaust gas also contains S0x
- the NOx absorbent described in Japanese Patent Laid-Open No. 6-17372652 absorbs SOx in addition to NOx. The amount of NOx that can be absorbed by the NOX absorbent will be reduced by the amount of SOx absorbed. Therefore, in the exhaust emission control device described in Japanese Patent Application Laid-Open No.
- the SO x absorbent that absorbs SOX in the exhaust gas is disposed upstream of the NO x absorbent, and the SO x absorption SOx in the exhaust gas is absorbed by the agent, so that SOX does not flow into the NOX absorbent. Disclosure of the invention
- the SOx absorbent has an air-fuel ratio in which the air-fuel ratio of the exhaust gas flowing into it is leaner than the stoichiometric air-fuel ratio, and the temperature of the SOx absorbent is higher than the so-called activation temperature. When it is high, it absorbs S ⁇ x in the exhaust gas.
- the air-fuel ratio of the exhaust gas flowing into it becomes the stoichiometric air-fuel ratio or a rich air-fuel ratio, and the temperature of the SOx absorbent is higher than the activation temperature (a certain temperature (Hereinafter referred to as “SOX release temperature”), the absorbed SOX is released. To do.
- S0 x absorbent has the original function of absorbing SOX in the exhaust gas, so when the 30 absorbent should absorb 30, the SOX absorbent will absorb S0 x. It is not preferable to release it. And this is not only for the exhaust purification system with SOX absorbent that aims to absorb S0 x in the exhaust gas, but also to capture the SOX in the exhaust gas. This also applies to the exhaust emission control equipment with the intended SOX capture material.
- the object of the present invention is that in an internal combustion engine equipped with a SO x capture material that captures SO x in exhaust gas, the SO x capture material releases SOX when the SO x capture material should capture SO x. This is to surely prevent this.
- an SO x trapping material for trapping SO x in exhaust gas is provided in an exhaust passage, and the SOX trapping material is the SOx trap.
- the air-fuel ratio of the exhaust gas flowing into the capture material is an air-fuel ratio leaner than the theoretical air-fuel ratio and the temperature of the SOX capture material is lower than a predetermined temperature, S 0 X in the exhaust gas is captured.
- the SOX capture material is captured.
- the first HC that supplies HC into the exhaust gas upstream of the S0X trapping material in a predetermined pattern is used as the HC supply control.
- Execute supply control, and the amount of SO x captured by the SO x trap If there are many, the HC supply control has a pattern that is different from the predetermined pattern, and the temperature of the SXX trapping material is prevented from being locally higher than the predetermined temperature.
- HC is supplied into the exhaust gas upstream of the SOX capture material in a pattern that suppresses the formation of a region in which the air-fuel ratio is locally rich in the exhaust gas flowing into the SOX capture material. Execute second HC supply control.
- the predetermined HC per unit time is supplied into the exhaust gas upstream of the SOX capture material
- O Pre-determined amount HC per unit time HC is supplied in the exhaust gas upstream of S0 X capture material
- the diffusibility into the exhaust gas is higher than the HC supplied into the exhaust gas upstream of the S X capture material.
- High HC is supplied into the exhaust gas upstream of the SO x trap.
- HC is supplied into the exhaust gas upstream of the OX trapping material so that the lean degree of the air-fuel ratio of the exhaust gas flowing into the X trapping material is maintained larger than the predetermined lean degree.
- the predetermined lean degree is set larger as the temperature of the S 0 X trapping material is lower.
- the local temperature rise amount of the S0 X trapping material per unit time is allowed per unit time allowed in the first HC supply control.
- HC is supplied into the exhaust gas upstream of the SOx trap so that it is kept smaller than the local temperature rise of the SOX trap.
- the unit S0 x capture so that the temperature rise of the entire Sx trapping material per hour is kept smaller than the temperature rise of the entire SOx trapping material per unit time allowed in the first HC supply control.
- HC is supplied into the exhaust gas upstream of the material.
- a particulate filter for collecting particulate matter in the exhaust gas is disposed in the exhaust passage downstream of the SO x trapping material, and one of the predetermined conditions is Particulate — A fuel removal condition that determines that the particulate matter collected in the particulate filter should be burned and removed by raising the temperature of the particulate filter to a predetermined target temperature.
- the first HC supply control is executed when the combustion removal condition is satisfied. In this case, HC is supplied into the exhaust gas upstream of the SO x trapping material with a temperature lower than the target temperature in the first HC supply control as the target temperature.
- the temperature amplitude of the SOX trapping material is maintained smaller than the temperature amplitude of the SOx trapping material allowed in the first HC supply control.
- HC is supplied into the exhaust gas upstream of the SOX capture material.
- a NOX absorbent that absorbs NOX in exhaust gas is disposed in the exhaust passage downstream of the SOX capture material, and one of the predetermined conditions is the NOX absorption NO x release conditions for which it is determined that NO x should be released from the agent, and when the second HC supply control is executed when the NO x release conditions are satisfied, the second x In the HC supply control, when the temperature amplitude of the SOX capture material satisfies the NOX release condition, the SOX capture allowed in the first HC supply control when the first HC supply control is executed. HC is supplied into the exhaust gas upstream of the SO x trap so that it is kept below the temperature swing of the catch.
- an oxidizing catalyst having an oxidizing ability higher than that of the SO trapping material is disposed in the exhaust passage upstream of the SO trapping material.
- FIG. 1 is a view showing a compression ignition type internal combustion engine equipped with an exhaust purification device of the present invention.
- Figures 2 (A) and (B) are diagrams showing the structure of the Patikyule tofil.
- FIG. 3 is a cross-sectional view of the surface portion of the catalyst carrier of the NO X catalyst.
- FIG. 4 is a cross-sectional view of the surface portion of the catalyst support of the S O X capture material.
- FIGS. 5A to 5C are views for explaining Nx release control of the exhaust purification system of the first embodiment.
- FIGS. 6A to 6C are views for explaining NO X release control of the exhaust purification system of the second embodiment.
- FIG. 7 is a diagram showing an example of a routine for executing N O X release control according to the embodiment of the present invention.
- FIGS. 8A to 8C are views for explaining PM removal control of the exhaust purification system of the seventh embodiment.
- FIGS. 9A to 9C are views for explaining PM removal control of the exhaust purification system of the eighth embodiment.
- FIG. 10 is a diagram showing an example of a routine for executing PM removal control according to the embodiment of the present invention.
- FIG. 11 is a diagram showing an example of a routine for performing NOX release control of the exhaust purification system of the 15th embodiment.
- FIG. 12 is a diagram showing an example of a routine for performing PM removal control of the exhaust purification system of the 16th embodiment.
- FIG. 13 is a view showing one of the compression ignition internal combustion engines to which the present invention can be applied.
- FIG. 14 is a view showing another one of the compression ignition type internal combustion engines to which the present invention can be applied.
- ⁇ 15 is a view showing still another one of the compression ignition type internal combustion engines to which the present invention can be applied.
- FIG. 1 shows a compression ignition type internal combustion engine equipped with the exhaust emission control device of the present invention.
- 1 is an engine body
- 2 is a combustion chamber of each cylinder
- 3 is an electronically controlled fuel injection valve for injecting fuel into each combustion chamber
- 4 is an intake manifold
- 5 is an exhaust manifold. It shows.
- the intake manifold 4 is connected to the outlet of the compressor 7 a of the exhaust outlet charger 7 through the intake duct 6, and the inlet of the compressor 7 a is connected to the air cleaner 8.
- a throttle valve 9 driven by a step motor is arranged in the intake duct 6, and a cooling device for cooling the intake air flowing in the intake duct 6 around the intake duct 6.
- the engine cooling water is guided into the cooling device 10 and the intake air is cooled by the engine cooling water.
- the exhaust manifold 5 is connected to the inlet of the exhaust turbine 7 b of the exhaust turbocharger 7.
- the outlet of the exhaust evening bin 7 b is connected to the SOX capture material 1 through the exhaust pipe 1 3.
- an HC supply valve 14 for supplying HC (hydrocarbon) to the exhaust gas flowing through the exhaust pipe 13 is attached to the exhaust pipe 13.
- the outlet of the SOX capture material 1 1 is connected to the NOX catalyst 1 2.
- the exhaust manifold 5 and the intake manifold 4 are connected to each other via an exhaust gas recirculation (hereinafter referred to as “EGR”) passage 15, and in the EGR passage 15, an electronically controlled EGR control valve 1 6 is arranged. Further, a cooling device 17 for cooling the EGR gas flowing in the EGR passage 15 is disposed around the EGR passage 15. In the embodiment shown in FIG. 1, the engine cooling water is guided into the cooling device 17 and the EGR gas is cooled by the engine cooling water.
- each fuel injection valve 3 is connected to a common rail 19 through a fuel supply pipe 18. Fuel is supplied to the common rail 19 from an electronically controlled variable discharge fuel pump 20, and the fuel supplied to the common rail 19 is supplied to the fuel injection valve 3 via each fuel supply pipe 18. Supplied.
- the electronic control unit 30 consists of a digital computer and is connected to each other by a bidirectional bus 3 1.
- ROM read-only memory
- RAM random access memory
- CPU microprocessor
- the SO x trap 1 1 is equipped with a temperature sensor 2 1 for detecting the temperature of the SOX trap 1 1, and the NO x catalyst 1 2 is used for detecting the temperature of the NO x catalyst 1 2.
- the temperature sensor 2 2 is installed. The output signals of these temperature sensors 2 1 and 2 2 are input to the input port 35 via the corresponding AD converters 37.
- a differential pressure sensor 2 3 for detecting the differential pressure across the N0 x catalyst 1 2 is attached to the N0 x catalyst 1 2, and the output signal of the differential pressure sensor 2 3 is the corresponding AD To input port 3 5 via converter 3 7 Entered.
- a load sensor 41 that generates an output voltage proportional to the amount of depression of the accelerator pedal 40 is connected to the accelerator pedal 40.
- the output voltage of the load sensor 41 is the corresponding AD converter 3 7 Through the input port 3 5.
- the input port 35 is connected to a crank angle sensor 42 that generates an output pulse every time the crankshaft is rotated by 15 °, for example.
- the output port 3 6 is connected to the fuel injection valve 3, the throttle valve 9 through the corresponding drive circuit 3 8, the step motor for driving, the HC supply valve 14, the EGR control valve 16, and the fuel pump 2. Connected to 0.
- N0 x catalyst 1 2 will be described.
- NO x catalyst 1 2 is supported on a particulate filter (hereinafter referred to as “fill evening”) having a honeycomb structure supported on a monolithic carrier or pellet-like carrier having a three-dimensional network structure.
- the N0X catalyst 12 can be supported on various supports.
- Figures 2 (A) and 2 (B) show the structure of the film 1 2a carrying the N0 x catalyst 1 2.
- Fig. 2 (A) shows a front view of Phil evening 12 a
- Fig. 2 (B) shows a side sectional view of Phil evening 12 a. As shown in FIGS.
- the filter 12a has a honeycomb structure and has a plurality of exhaust flow passages 60, 61 extending in parallel with each other. These exhaust flow passages are constituted by an exhaust gas inflow passage 60 whose downstream end is closed by a plug 62 and an exhaust gas outflow passage 61 whose upper end is closed by a plug 63.
- the hatched part shows the plug 6 3. Therefore, the exhaust gas inflow passage 60 and the exhaust gas outflow passage 6 1 are alternately arranged through the thin partition walls 64. Yes.
- each exhaust gas inflow passage 60 is surrounded by four exhaust gas outflow passages 61, and each exhaust gas outflow passage 61 has four It is arranged so as to be surrounded by the exhaust gas inflow passage 60.
- the fill gas 1 2 a is formed of a porous material such as a cordierite. Therefore, the exhaust gas flowing into the exhaust gas inflow passage 60 is indicated by an arrow in FIG. 2 (B). As shown in the drawing, the gas flows out into the adjacent exhaust gas outflow passage 6 1 through the surrounding partition wall 64.
- a catalyst carrier made of, for example, alumina is supported on the upper and inner wall surfaces of the pores in the partition wall 64, and FIG. 3 schematically shows a cross section of the surface portion of the catalyst carrier 45.
- the noble metal catalyst 4 6 is dispersedly supported on the surface of the catalyst support 4 5, and further, N 0 X absorbent 4 7 is supported on the surface of the catalyst support 4 5. Layer is formed.
- platinum (Pt) is used as the shell metal catalyst 4 6, and the component constituting the N X absorbent 4 7 is, for example,
- Alkaline metals such as calcium (K), sodium (Na), cesium (Cs), alkaline metals such as barium (Ba), calcium (Ca), At least one selected from rare earths such as orchids (L a) and Itsu ⁇ Rium (Y) is used.
- the ratio of the air and fuel (hydrocarbon) supplied into the exhaust passage upstream of the engine intake passage, combustion chamber 2, and NOX catalyst 1 2 is called the exhaust gas air-fuel ratio.
- the air-fuel ratio of the exhaust gas When the air-fuel ratio of the exhaust gas is leaner than the stoichiometric air-fuel ratio, it absorbs Nx and releases the absorbed NOX when the oxygen concentration in the exhaust gas decreases.
- barium (B a) is used as a component constituting the NO x absorbent 4 7 as an example.
- the air-fuel ratio of the exhaust gas is lean, that is, the oxygen concentration in the exhaust gas
- N is high
- N 0 contained in the exhaust gas is oxidized on platinum 46 to N 0 2 as shown in Fig. 3, and then absorbed into NO X absorbent 47.
- N 0 X is absorbed in N 0 X absorbent 4 7.
- N_ ⁇ 2 is produced on the surface of the platinum 4 6, N_ ⁇ X absorbent 4
- N 0 2 is absorbed into the N 0 X absorbent 4 7 to produce nitrate (N 0 3 —) unless the N 0 X absorption capacity of 7 is saturated.
- the reaction is reversed because the oxidation concentration in the exhaust gas decreases.
- the nitrate ions NO 3 in the NO X absorbent 4 7
- the released Nx is reduced by unburned HC and CO contained in the exhaust gas.
- S_ ⁇ the exhaust gas x (sulfur oxides), that is, includes the S ⁇ 2, this S_ ⁇ 2 flows into N_ ⁇ x catalyst 1 2, S_ ⁇ 2 This platinum It is oxidized at 4 6 to S 0 3 . Then, S_ ⁇ 3 of this, while being absorbed in the NO X absorbent 4 in 7 combined with barium oxide (B a ⁇ ), in the NO x absorbent 4 7 in the form of sulfate (S_ ⁇ 4) Diffuses to produce stable sulfate (B a S0 4 ).
- N_ ⁇ X absorbent 4 7 While only, to N_ ⁇ X absorbent 4 7 has a strong basicity, the sulfate salt (B a S_ ⁇ 4) is difficult is decomposed is stable, simply re pitch the air-fuel ratio of the exhaust gas By just making it, the sulfate (B a S0 4 ) remains as it is without being decomposed. Therefore, the N_ ⁇ X absorbent 4 in 7, will be increased sulfate (B a S_ ⁇ 4) over time, and thus, N_ ⁇ X absorbent 4 7 over time The amount of N0 X that can be absorbed will decrease.
- the exhaust gas flowing into the NO X catalyst 1 1 in the state where the temperature of the NO x catalyst 1 1 is raised to the above SO x release temperature at 600 or more is empty.
- SOX is released from the NO x absorbent 47.
- NOx is released little by little from the NO X absorbent 47. Therefore, in order to release all SOX from the N0 X absorbent 4 7, the air-fuel ratio of the exhaust gas must be kept for a long time, so that a large amount of fuel or reducing agent is consumed. There is a problem that it becomes necessary.
- SOx released from the SOx absorbent 47 is discharged into the atmosphere, which is also not preferable.
- the SOO capture material 1 1 is arranged upstream of the NOX catalyst 1 2 and is contained in the exhaust gas by the SOX capture material 1 1. It captures the rare SO x, thereby preventing SOX from flowing into the NO x catalyst 12. Next, this SOX capture material 1 1 will be explained.
- the S O X capture material 11 is made of, for example, a monolith catalyst having a honeycomb structure, and has a large number of exhaust gas flow holes extending straight in the axial direction of the 30 capture material 1 1.
- a catalyst carrier made of alumina for example, is supported on the inner peripheral wall surface of each exhaust gas circulation hole.
- a cross section of the surface portion of the catalyst carrier 50 is shown schematically.
- a coat layer 51 is formed on the surface of the catalyst support 50, and the noble metal catalyst 52 is dispersed on the surface of the coat layer 51. It is supported.
- platinum (Pt) is used as the noble metal catalyst 52.
- components constituting the coating layer 51 include force lithium (K), sodium (N a), alkali metals such as cesium (Cs), alkali earths such as norium (Ba), calcium (Ca), lanthanum (La), yttrium (Y) At least one selected from such rare earths is used. That is, the coating layer 5 1 of the S0 x trapping material 11 has a strong basicity.
- S_ ⁇ 2 SO x contained in the exhaust gas, mainly S_ ⁇ 2, as shown in FIG. 4, it is oxidized at platinum 5 2, then is trapped in the coat layer 5 1. That is, S_ ⁇ 2 diffuses to coat layer 5 in 1 in the form of sulfate (S_ ⁇ 4 2 _), to form a sulfate.
- the coat layer 51 has a strong basicity. Therefore, as shown in FIG. 4, a part of S 0 2 contained in the exhaust gas is a coat. Captured directly in layer 51.
- the exhaust gas also contains particulate matter.
- Particulate matter contained in the catalyst is collected on the filter 1 2a carrying the NOX catalyst 12 and is sequentially oxidized.
- the particulate matter gradually accumulates on the filter 1 2 a, and in this case, the amount of particulate matter deposited increases. Then, the engine output will decrease. Therefore, when the amount of accumulated particulate matter increases, the deposited particulate matter must be removed. In this case, the accumulated particulate matter is oxidized and removed when the temperature of the filter 12 a is raised to about 60 ° C. in excess of air.
- the air-fuel ratio of the exhaust gas is reduced under the lean air flow ratio.
- the temperature is raised so that the accumulated particulate matter is removed by oxidation.
- the amount of deposited particulate matter exceeds the allowable capacity when the differential pressure across the filter 1 2 a detected by the differential pressure sensor 2 3 exceeds the allowable value.
- temperature rise control is performed to increase the temperature of the fill 12 a while maintaining the air-fuel ratio of the exhaust gas flowing into the fill 12 a lean.
- the SO x trapping action of the above-described SOO trapping material 11 is such that the air-fuel ratio of the exhaust gas flowing into the SOx trapping material 11 is leaner than the stoichiometric air-fuel ratio, and This is performed when the temperature is higher than a certain temperature (hereinafter referred to as “activation temperature”).
- the S o x trapping material 11 has a certain temperature (hereinafter referred to as “the stoichiometric air-fuel ratio” or higher than the above-mentioned activation temperature). If it becomes higher than (SO x release temperature), the captured SOO X will be released.
- At least S ⁇ make sure that the air-fuel ratio of the exhaust gas flowing into the X trapping material 1 1 does not become the stoichiometric air-fuel ratio or higher, and that the temperature of the SOX trapping material 1 1 does not become higher than the SOX release temperature. It is necessary to keep it.
- the temperature of the SOx trapping material 11 as a whole is lower than the SOx release temperature, it may be locally higher than the SOx release temperature.
- the amount of SOx trapped in the SOx trapping material 1 1 (hereinafter referred to as "SOx trapping amount") is relatively large and the stoichiometric air-fuel ratio or higher. If air-fuel ratio exhaust gas flows into S ⁇ x capture material 1 1, SO x may be released from the SOX capture material 1 1 part where the temperature is locally higher than the S ⁇ x release temperature. .
- the air-fuel ratio of the exhaust gas flowing into the SOO capture material 1 1 is lean as a whole, it may become locally a lit.
- SO x trapping material 1 1 SO may be released from some parts. That is, in order to reliably prevent SO x from being released from the SO x trapping material 1 1, the amount of SO x trapped by the 30 trapping material 1 1 is relatively large, and 30 1
- the air-fuel ratio of the exhaust gas flowing into 1 is the stoichiometric air-fuel ratio or higher, or when it is estimated that the air-fuel ratio is higher than the stoichiometric air-fuel ratio or SO Even if the temperature of the x trapping material 1 1 is local, it is necessary not to be higher than the SO x emission temperature.
- SO x trapping material 1 1 has a relatively large amount of SO x trapped, and SO x trap 1 When the temperature of 1 is higher or higher than the SOX release temperature, SO x Even if the air-fuel ratio of the exhaust gas flowing into the trapping material 1 1 is local, it is necessary to prevent it from becoming the stoichiometric air-fuel ratio or more.
- the air-fuel ratio of the exhaust gas flowing into the OX trapping material 1 1 also becomes the stoichiometric air-fuel ratio or higher than that. Therefore, at this time, if the amount of S0 X captured by S O X extract material 1 1 is relatively large, S 0 X capture material 1 1 to S
- the SOX trapping amount of the 30 trapping material 1 1 is determined in advance (hereinafter referred to as “placement”). If the amount is less than that, simply perform NO X release control to release NO X from the NO X absorbent 47 (hereinafter referred to as ⁇ normal NO x release control)
- HC supply supplying HC from the HC supply valve 14 into the exhaust gas
- HC supply rate The amount of HC that is supplied.
- ⁇ HC supply time '' The time during which HC is supplied into the exhaust gas from the HC supply valve 14
- ⁇ HC supply interval '' The time interval for each HC supply is called ⁇ HC supply interval ''.
- Release control or SOX release suppression ⁇ The number of times HC is supplied in Ox release control is called “HC supply frequency”.
- the normal NO X release control of the first embodiment is when it is determined that NO x should be released from the NO X absorbent 47, and the SOx trapping material 1 1 Performed when less than a predetermined amount.
- the HC supply rate is a predetermined HC supply rate (hereinafter referred to as "normal HC supply rate”) Q a and HC supply time.
- HC supply with a predetermined HC supply time (hereinafter referred to as “normal HC supply time”) Ta is determined in advance with a predetermined HC supply interval (hereinafter referred to as “normal HC supply interval”) I a.
- Perform the specified number of HC supplies hereinafter referred to as “normal HC supply times”, 3 times in the example shown in Fig. 5 (A)).
- the HC supply rate in each HC supply, the HC supply time in each HC supply, and the number of HC supply are determined when the NOX catalyst is completed when all HC supply is completed. 1 Ensure that the total amount of HC supplied to 2 is sufficient to release a predetermined amount of NO x from the NO X absorbent 47 (hereinafter referred to as the “predetermined HC amount”). Is set. Therefore, according to the normal NO x release control of the first embodiment, a predetermined amount of NO x can be released from the NO x absorbent 47.
- S0 X release suppression ⁇ NO X release control is determined when NO x should be released from the NO X absorbent 47, and the SO x capture material 11 This is done when the amount of SOX captured is greater than the predetermined amount.
- This SOX release suppression ⁇ NO x release control 5 As shown in (B), the HC supply rate is
- H C supply time T a equal to H C supply time T a is
- the number of times of supply is greater than the number of normal HC feeds described above with an interval Ib shorter than the C feed port interval Ia. According to this, since the amount of HC supplied from the HC supply port valve 14 to the exhaust gas in one HC supply is small,
- the occurrence of a region where the air-fuel ratio is locally large and rich in the exhaust gas is suppressed, so a partial region of the S o X catch material 1 1
- the temperature is suppressed from becoming higher than the SO x release temperature. Therefore, the temperature of the S 0 X trapping material 1 1 is suppressed from being locally higher than the S O X release temperature, and the S O x trapping material 1 1 is reliably suppressed from being released.
- the HC supply rate is equal to the normal HC supply.
- HC supply rate Q b smaller than the supply rate Q a and HC supply time T c longer than the normal HC supply time above HC supply at intervals I c longer than the normal HC supply interval I a Therefore, the same number of times as the above normal HC supply times may be used.
- the HC supply rate in each HC supply is small, HC supplied from the HC supply valve 14 is likely to diffuse into the exhaust gas. For this reason, since the temperature of the SO x trapping material 1 1 is suppressed from being locally higher than the SOX release temperature, the release of S0 x from the 30 trapping material 1 1 is reliably suppressed. .
- the total HC amount supplied to the NO X catalyst 12 when all the HC supply is completed becomes the predetermined HC amount.
- the HC supply interval is set to an interval Ib that is half the normal HC supply interval Ia.
- the HC supply rate is half the normal HC supply rate Q a HC supply rate Q b and the HC supply time is twice the normal HC supply time Ta.
- Time Tc is set, and the number of HC supplies is the same as the number of normal HC supplies.
- the upper line indicates the supply of HC from the HC supply valve 14 into the exhaust gas
- the lower line indicates the expansion stroke in a specific cylinder. Late or exhaust
- the fuel injection from the fuel injection valve 3 during the stroke is shown.
- the fuel injection from the fuel injection valve 2 in the latter half of the expansion stroke or during the exhaust stroke in a specific cylinder is referred to as “post fuel injection”, and each post fuel injection is performed per unit time.
- post fuel injection rate The amount of fuel injected from the fuel injection valve 2 is referred to as “post fuel injection rate”, and the time during which fuel is injected from the fuel injection valve 2 in one post fuel injection is referred to as “post fuel injection time”.
- post fuel injection interval The time interval at which each post fuel injection is performed
- post fuel injection frequency The number of times one post fuel injection is performed.
- NO x release control when it is determined that NO x should be released from the NO x absorbent 47 (that is, when the NO x release condition is satisfied), SO Normally, NO X release control is executed when the amount of S0 x trapped by the x trapping material 1 1 is smaller than the predetermined amount (that is, when the SO x release suppression condition is not satisfied).
- NO X release control as shown in the upper line of Fig. 6 (A), the HC supply rate is equal to the normal HC supply rate Q a and the HC supply rate Q a is HC supply.
- the HC supply whose time is a time Ta equal to the normal HC supply time Ta is performed the same number of times as the normal number with an interval Ia equal to the normal HC supply interval Ia. At this time, as indicated by the lower line in FIG. 6 (A), post fuel injection is not performed in any of the cylinders.
- the HC supply rate in each HC supply, the HC supply time in each HC supply, and the number of HC supplies are determined by the NOX catalyst 1 2 when all the HC supplies are completed. It is set so that the total amount of HC supplied is equal to the specified HC amount.
- the S0x emission suppression / NOx emission control is executed.
- the HC supply rate is smaller than the normal HC supply rate Q a above HC supply rate Q b
- the HC supply time is equal to the normal supply time Ta, and the HC supply is performed the same number of times as the normal number of times with the interval Ia equal to the normal HC supply interval Ia.
- the post fuel injection rate is a boost fuel injection rate Q bp smaller than the normal HC supply rate Q a and the normal fuel injection time is the normal fuel injection time.
- the post fuel injection having a time Tap equal to the HC supply time Ta is performed the same number of times as the normal HC supply with the interval lap equal to the normal HC supply interval la. According to this, since the amount of HC supplied from the HC supply valve 14 to the exhaust gas is small in one HC supply, the HC supplied from the HC supply valve 14 easily diffuses into the exhaust gas. For this reason, the HC injected from the HC supply valve 14 suppresses the temperature of the S0x trapping material 11 from being locally higher than the SOX release temperature.
- the fuel injected from the fuel injection valve 3 during the latter half of the expansion stroke or during the exhaust stroke in a specific cylinder is reformed and lightened by the heat in the cylinder.
- the lightened fuel passes through S 0 x capture material 1 1 and is supplied to N 0 x catalyst 1 2, but this lightened fuel enters the exhaust gas.
- the fuel injected from the fuel injection valve 3 during the latter half of the expansion stroke or during the exhaust stroke in a specific cylinder suppresses the temperature of the SO x trap 11 from being locally higher than the S0 X release temperature. Is done. Therefore, the release of SOX from the SO x trap 11 is reliably suppressed.
- the SO x release suppression ⁇ NO x release control As shown in FIG. 6 (C), HC (fuel) may be supplied to the NO x catalyst 12 only by post fuel injection.
- the post fuel injection rate is equal to the normal HC supply rate Q a described above.
- Post fuel injection with a time Tap equal to the normal HC supply time T a is the same as the normal HC supply frequency with an interval I a P equal to the normal HC supply interval I a.
- HC is not supplied from the HC supply valve 14 into the exhaust gas. According to this, through S ⁇ X capture material 1 1
- the catalyst (HC) fed to the X catalyst 1 2 is lightened and easily diffuses into the exhaust gas. For this reason, the temperature of the S O x trapping material 1 1 is suppressed from being locally higher than the S O X emission temperature.
- the HC supply port rate is set to HC supply rate Qb, which is half of the normal HC supply rate Qa
- the HC supply time is set to The time Ta equal to the normal HC supply time Ta
- the HC supply frequency equal to the normal HC supply frequency
- the boss h fuel injection rate is half the normal HC supply rate Qa.
- the post injection time is set to a time Tap equal to the normal HC supply time Ta
- the post fuel injection frequency is set equal to the normal HC supply frequency.
- both the HC supply interval and the boss / fuel injection interval are set to intervals Ia and Iap equal to the normal HC supply interval Ia.
- the post fuel injection rate is set to the post fuel injection rate Q ap equal to the normal HC supply rate Q a
- the post fuel injection time is set to the normal HC supply time T a. Is equal to the time Tap
- the number of post fuel injections is equal to the number of normal HC supplies.
- the post fuel injection interval is set to an interval I ap equal to the normal HC supply interval I a.
- the post fuel injection is shown to be executed at the same timing as the HC supply.
- the post fuel injection timing is based on the crank angle of the internal combustion engine. Strictly speaking, in many cases, the post fuel injection timing will not be the same as the HC supply timing, and will be slightly offset.
- the post fuel injection interval is equal to the normal HC supply interval, but for the same reason, strictly speaking, in most cases, the post fuel injection interval is usually the HC supply interval. It will not be equal to the interval, and will shift slightly.
- the HC supplied to the NOX catalyst 12 when post fuel injection is performed in the latter half of the expansion stroke is more likely to be post fuel.
- injection is performed during the exhaust stroke, it is more diffusible into the exhaust gas than HC supplied to the NO x catalyst 12. Therefore, in the above-described embodiment, as a method for supplying HC to the NO x catalyst 12 as the NO x release control, only the post fuel injection is adopted, and in the normal NO x release control, the post fuel is used.
- HC is supplied to the NO x catalyst 1 2 by performing injection during the exhaust stroke.
- NO x catalyst 1 is controlled by performing post fuel injection in the second half of the expansion stroke in the S0 X release suppression / NO X release control.
- HC may be supplied to 2. This also reliably suppresses the release of SO from the SO x trapping material 11.
- NOX emission control of the exhaust purification system of the third embodiment will be described.
- the Nx release control of the third embodiment when the NOx release condition is established and the Sx release suppression condition is not established, the same control as the normal NOx release control of the first embodiment described above. Is executed.
- each HC supply is set to the normal HC with the normal HC supply rate, the normal HC supply time, and the normal HC supply interval in the same manner as the normal NOX release control of the first embodiment described above.
- the HC lightened by fractional distillation is prepared in advance, and a part of the HC supplied into the exhaust gas from the HC supply valve 14 in each HC supply is referred to as this lightened HC. As mentioned above, lighter HC tends to diffuse into the exhaust gas.
- the temperature of the 30 trapping material 11 1 is suppressed from being locally higher than the S O X release temperature. Therefore, the release of S0 X from the S O X trapping material 1 1 is reliably suppressed.
- NO X release control of the exhaust purification system of the fourth embodiment will be described.
- NO X release control of the fourth embodiment when the NO x release condition is satisfied and the SOX release suppression condition is not satisfied, the same control as the normal NOX release control of the first embodiment described above is executed. .
- the NO X release control of the fourth embodiment the NO x release condition is satisfied. Then, when the S0 x release suppression condition is satisfied, the SO x release suppression ⁇ ⁇ 0 ⁇ release control is executed.
- the HC in the exhaust gas burns into the exhaust gas in the SOX capture material 1 1, the temperature of the NO x catalyst 1 2 corresponding to the temperature of the SOX capture material 1 1 (below) Control the HC supply rate in each HC supply, the HC supply time in each HC supply, and the HC supply interval so that the temperature of NO x catalyst 1 2 is maintained lower than the “maximum NO X catalyst temperature” To do.
- the temperature of S0 x capture material 1 1 will be higher than the temperature at which the HC flowing into it will burn at once. Yes.
- the SO x release suppression ⁇ N 0 x release control keeps the temperature of the NO X catalyst 12 lower than the above maximum NO X catalyst temperature.
- the SOX release suppression / NOx release control of the fourth embodiment when all the HC supply is completed, the total amount of HC supplied to the NOX catalyst 12 becomes the above-mentioned predetermined HC amount.
- NO x release control of the exhaust emission control device of the fifth embodiment will be described.
- NO X release control of the fifth embodiment when the NO x release condition is satisfied and the S0 X release suppression condition is not satisfied, the first embodiment The same control as the normal NO x release control is executed.
- the SOx release suppression / Ox release control when the NO x release condition is satisfied and the SOx release suppression condition is satisfied, the SOx release suppression / Ox release control is executed.
- the temperature rise and fall range of NO X catalyst 1 2 (hereinafter referred to as “temperature amplitude”) is normally allowed for NO x release control.
- Temperature amplitude of NO x catalyst 1 2 The HC supply rate in each HC supply, the HC supply time in each HC supply, and the HC supply interval are controlled so as to be kept smaller. That is, in the S0x release suppression / NOx release control, HC is supplied intermittently, and therefore, the H 2 O 3 is intermittently supplied to the NOx catalyst 12.
- the temperature of the NO x catalyst 12 rises due to the reaction heat of HC in the NO x catalyst 12, and then falls.
- the large temperature amplitude of the NO x catalyst 12 has a large range of rise and fall of the temperature of the S O x trapping material 11.
- the temperature of the SO x trapping material 11 is at least locally higher than the SOX release temperature. If the amount is higher than the fixed amount, SOX may be released from the S0 x capture material 1 1.
- the temperature amplitude of NOx catalyst 12 is kept smaller than the temperature amplitude of NOx catalyst 12 that is normally allowed in NOx release control.
- the HC supply rate in each HC supply, the HC supply time in each HC supply, and the HC supply interval are controlled. According to this, it is possible to suppress the temperature of the S o X trap 11 from being locally higher than the S O x release temperature. Therefore, the release of SOx from the SOx trapping material 1 1 is reliably suppressed.
- SOX release suppression ⁇ NOX release control The HC supply rate in each HC supply, the HC in each HC supply, so that the total HC amount supplied to the NO x catalyst 12 when all the HC supply is completed is equal to the above specified HC amount. It is preferable to set the supply time and the number of HC supply.
- NO X release control of the exhaust emission control device of the sixth embodiment will be described.
- the same control as the normal NO X release control of the first embodiment described above is executed when the NO x release condition is satisfied and the SOX release suppression condition is not satisfied. Is done.
- the S O x release suppression ⁇ X ⁇ x release control is executed.
- the air / fuel ratio of the exhaust gas supplied to the NOx catalyst 12 is maintained to be less than the target level of the normal NOx release control.
- the HC supply rate in each HC supply, the HC supply time in each HC supply, and the HC supply interval are controlled. That is, when the degree of air-fuel ratio of exhaust gas flowing into NO x catalyst 12 is large, the degree of air-fuel ratio of exhaust gas flowing into SOx trapping material 11 is also large. Become.
- the air / fuel ratio of the exhaust gas supplied to the NOx catalyst 12 is as follows: For example, it is estimated from the output of an air-fuel ratio sensor attached to the exhaust pipe downstream of N0 x catalyst 1 2.
- HC flowing into the 30 capture material 1 1 adheres to a partial region of the S 0 X capture material 1 1.
- the attached HC does not burn and remains attached there.
- the temperature of the region of S0x trapping material 11 to which HC is attached rises to the combustion temperature of HC, the attached HC may be burned into the air. That is, the lower the temperature of the S O x trapping material 11, the more likely the HC attached to the S Ox trapping material 11 will burn.
- the degree of air-fuel ratio latching of the exhaust gas supplied to the NOX catalyst 12 is normally set in the NOX release control.
- the temperature is kept smaller than the target degree of latch, the lower the temperature of S0 x capture material 11 is, the smaller the degree of air-fuel ratio of exhaust gas supplied to NO x catalyst 1 2 is. You may make it maintain.
- FIG. 7 shows an example of a routine for performing Nx release control according to the embodiment of the present invention.
- the routine of FIG. 7 first, in step 10, whether or not the amount of NO x ⁇ ⁇ absorbed in the NO x absorbent 4 7 is larger than the allowable value ⁇ ( ⁇ ⁇ ⁇ > ⁇ ) (ie, ⁇ ⁇ ⁇ whether or not the release condition is satisfied.
- the routine is terminated as it is.
- Step 1 the process proceeds to Step 1 1, and the S ⁇ x capture amount ⁇ SOX of the 30,000 capture material 1 1 is larger than the predetermined amount / 3 ( ⁇ S ⁇ X> j8) (that is, whether or not the S0 x emission suppression condition is satisfied).
- step 11 When it is determined in step 11 that ⁇ S0 X> jS, the process proceeds to step 12 and the first to sixth embodiments described above are performed. SO X release suppression-Execute one of the NOX release controls. On the other hand, when it is determined in step 1 1 that ⁇ S ⁇ X ⁇ iS
- Step 13 one of the normal N X release control of the first to sixth embodiments described above is executed.
- ⁇ PM combustion temperature The temperature is raised to the above temperature, and the particulate matter deposited on the filter 12 a is burned and removed (hereinafter referred to as “PM removal control”).
- PM removal control in order to raise the temperature of the filter 11 2a while maintaining the air-fuel ratio of the exhaust gas flowing into the filter 12a to be lean, it flows into the filter 12a.
- HC is supplied into the exhaust gas from the HC supply valve 14. That is, when HC is supplied into the exhaust gas from the HC supply valve 14, HC is supplied to the fill 12 a.
- the temperature of the SO x trapping material 11 is also relatively high. For this reason, the temperature of the SO x trapping material 11 is locally increased during the PM removal control. It can also be said that it tends to be higher than the SOX release temperature. In any case, in order to reliably suppress the release of SO x from SO x trapping material 1 1 during execution of PM removal control, the SO x trapping amount of SO x trapping material 1 1 is compared. S0 X capture material 1 When the exhaust gas flows into the exhaust gas 1 1, it is possible to suppress the formation of a locally rich region of the air-fuel ratio, or SO x capture material. 1 It is necessary to suppress the temperature of 1 from becoming locally higher than the SOX release temperature.
- PM removal control of the exhaust purification system of the seventh embodiment will be described.
- the PM removal control of the seventh embodiment when the amount of the particulate matter deposited on the fill 12a exceeds the allowable amount (that is, when the PM removal condition is satisfied), When the SOX trapping amount of the trapping material 11 is smaller than the above-mentioned predetermined amount (that is, when the S0x emission suppression condition is not satisfied), normal PM removal control is executed. In this normal PM removal control, as shown in Fig.
- the HC supply rate is a predetermined HC supply rate (hereinafter referred to as “normal HC supply rate”) Q d and the HC supply time
- Predetermined HC supply with a predetermined HC supply time hereinafter referred to as “normal HC supply time” T d with a predetermined HC supply interval (hereinafter referred to as “normal HC supply interval”) I d
- normal HC supply time a predetermined HC supply time
- I HC supply interval predetermined HC supply interval
- the number of times of HC supply hereinafter referred to as “normal number of HC supplies”, 3 times in the example shown in Fig. 8 (A)).
- the HC supply rate in each HC supply, the HC supply time in each HC supply, and the number of HC supplies are calculated based on the PM combustion temperature.
- the total amount of HC supplied to the filter 12 a burns the particulate matter deposited in the filter 1 2 a ⁇ by a predetermined amount.
- the amount of HC is sufficient to be removed (hereinafter referred to as “predetermined amount of HC”). Therefore, according to the normal PM removal control of the seventh embodiment, the particulate matter deposited on the fill 12a can be burned and removed by a predetermined amount.
- the HC supply rate is the normal HC supply rate Q d HC supply rate Q e which is smaller than the above normal HC supply time T d and HC supply time is equal to the above normal HC supply time T d. Normally, it is performed more times than the number of HC supply. According to this, the HC supply valve 14 supplies the exhaust gas to the exhaust gas in one HC supply.
- the HC supply rate is HC supply rate Q e which is smaller than the above normal HC supply rate Q d and the HC supply time is longer than the above normal HC supply port time.
- HC supply which is T f for a long time, usually above
- the same number of times of the normal HC supply may be performed with an interval If longer than the HC supply interval Id. According to this, since the HC supply rate in each HC supply is small, HC supplied from the HC supply valve 14 is diffused in the exhaust gas. For this reason, the formation of a region where the air-fuel ratio is locally rich in the exhaust gas is suppressed.
- the C supply interval and the number of H C supplies are set so that at least the temperature of the fill can be raised to the PM combustion temperature.
- the SO x emission suppression and PM removal control The HC supply rate in each HC supply, the HC in each HC supply, so that the total HC amount supplied to Phil Y 12a when all HC supply is completed is the above specified HC amount. It is preferable to set the supply time and the number of HC supply. Therefore, in the example shown in Fig. 8 (B), the HC supply rate is half the normal HC supply rate Qd, and the HC supply time is equal to the normal HC supply time Td. And the number of HC supply is twice the number of normal HC supply. In the example shown in FIG. 8 (B s), the HC supply interval is an interval I e that is half of the normal HC supply interval I d.
- the HC supply rate is set so that the total amount of HC supplied to Phil 12a when the supply of all HC is completed becomes the specified HC amount.
- HC supply rate Q e which is half of the normal HC supply rate Q d above
- HC supply time is set to T f which is twice the normal HC supply time T d above
- the number of HC supply is the same as the above normal HC supply frequency It is said.
- the HC supply interval is about 1.5 times the normal HC supply interval.
- the upper line indicates the supply of HC from the HC supply valve 14 into the exhaust gas
- the lower line indicates the expansion stroke in a specific cylinder. It shows fuel injection from the fuel injection valve 3 in the second half or during the exhaust stroke.
- normal PM removal control is executed when the PM removal condition is satisfied and the SOX release suppression condition is not satisfied.
- the HC supply rate is equal to the normal HC supply rate Q d above, and the HC supply time HC supply with a time T d equal to the normal HC supply time T d above, and the normal HC supply interval I d Is equal to the normal number of times with an interval I d equal to and this time
- the boss does not perform fuel injection in any cylinder.
- the HC yarn feeding rate in each HC supply, the HC supply time in each Hc supply, and the number of HC supply times are
- the SOx release suppression / ⁇ ⁇ removal control is executed.
- the HC supply rate is smaller than the normal HC supply rate Q d above.
- HC supply time equal to the normal supply time is equal to the normal supply time Id, and the HC supply time is equal to the normal number of times as shown in FIG. 9 (B).
- the phosphine fuel injection rate is a boss h fuel injection rate Q e P smaller than the normal HC supply rate Q d and the post fuel injection time is the normal HC supply time.
- Post fuel injection with a time T dp equal to the clue time T d is
- the H C supplied from the HC supply valve 14 suppresses a region in which the air-fuel ratio is locally large and rich in the exhaust gas.
- the fuel injection valve in a specific cylinder during the latter half of the expansion stroke or during the exhaust stroke is likely to diffuse into the exhaust gas.
- the fuel injected from No. 3 is reformed by the heat in the cylinder and lightened. It is. This lightened fuel is easy to diffuse into the exhaust gas. For this reason, it is suppressed that a U-shaped region in which the air-fuel ratio is locally large is generated in the exhaust gas by the fuel injected from the fuel injection valve 3 in the latter half of the expansion stroke or during the exhaust stroke in a specific cylinder. Therefore, S
- HC (fuel) is supplied to the filter 12a only by post fuel injection. You can do it. That is, as shown in the lower line of FIG. 9 (C), the post fuel injection rate is equal to the normal HC supply rate Q d and the post fuel injection rate Q dp is the post fuel injection rate.
- the post fuel injection whose fuel injection time is equal to the normal HC supply time T d is the same number of times as the normal HC supply frequency with the interval I dp equal to the normal HC supply interval I d. May be. Of course, at this time, as shown in the upper line of FIG.
- the HC supply rate in each HC supply, the HC supply time in each HC supply, the HC supply interval, and the number of HC supplies are at least the filter settings. It is set so that the temperature of 1 2 a can be raised to the PM combustion temperature.
- the number of times of HC supply is equal to the number of times of normal HC supply
- the post fuel injection rate is set to the post fuel injection rate Q dp, which is half of the normal HC supply rate Q d
- the post injection time is The time T dp is equal to the normal HC supply time T d
- the number of post fuel injections is equal to the number of normal HC supply times.
- the HC supply interval and the boost fuel injection interval are set to intervals Id and Idp equal to the normal HC supply interval Id.
- the total amount of HC (fuel) supplied to the fill 12a when all the HC supply and all post fuel injections are completed is the predetermined value.
- the post fuel injection rate is equal to the normal HC supply rate Q d above, so that the HC (fuel) amount is equal, and the post fuel injection time is equal to the normal HC supply time T d above.
- the time T dp is assumed, and the number of post fuel injections is set equal to the number of normal HC supply times.
- the post fuel injection interval is set to an interval I d P equal to the normal HC supply interval I d.
- the post fuel injection is shown to be executed at the same timing as the HC supply, but the post fuel injection timing depends on the crank angle of the internal combustion engine. Because it is controlled based on strict To be precise, in many cases, the post fuel injection timing is not the same as that of the HC supply evening, and is slightly shifted. In the example shown in Fig. 9, it is explained that the post fuel injection interval is equal to the normal HC supply interval, but for the same reason, strictly speaking, in many cases, the post fuel injection interval is usually set to the normal HC supply interval. It will not be equal to the interval, and will shift slightly.
- PM removal control of the exhaust emission control device will be described.
- the same control as the normal PM removal control of the seventh embodiment is executed when the PM removal condition is satisfied and the SOX release suppression condition is not satisfied.
- each HC supply is set to a normal HC with the normal HC supply rate, normal HC supply time, and normal HC supply interval, as in the normal NO X release control of the seventh embodiment.
- the HC lightened by fractional distillation is prepared in advance, and a part of the HC supplied into the exhaust gas from the HC supply valve 14 in each HC supply is referred to as this lightened HC.
- lighter HC tends to diffuse into the exhaust gas. For this reason, since a region where the air-fuel ratio is locally rich in the exhaust gas is suppressed, the release of S0X from the S0x trapping material 11 is reliably suppressed.
- PM removal control of the exhaust emission control device of the tenth embodiment will be described.
- the same control as the normal PM removal control of the seventh embodiment is executed when the PM removal condition is satisfied and the SOX release suppression condition is not satisfied.
- the PM removal control of the 10th embodiment the PM removal condition is satisfied. Then, when the SO x release suppression condition is satisfied, SO x release suppression ⁇ ⁇ ⁇ removal control is executed.
- the temperature of S ⁇ X trapping material 11 is kept lower than the temperature at which HC in the exhaust gas burns into the air in S ⁇ X trapping material 11
- the HC supply rate in each HC supply, the HC supply time in each HC supply, and the HC supply interval are controlled. According to this, even if a region where the air-fuel ratio is locally rich is formed in the exhaust gas,? 10 is 50 O X trapping material 1 1 is prevented from burning at once. For this reason, since the temperature of the SO x trapping material 11 is locally suppressed from being higher than the S0 x emission temperature, the SO x trapping material 11 is reliably prevented from being released. Is done.
- At least the HC supply rate in each HC supply, the HC supply time in each HC supply, the HC supply interval, and the number of HC supplies are at least a filter. It is set so that the temperature of evening 12 a can be raised to ⁇ ⁇ combustion temperature.
- the total amount of HC supplied to the filter 12 a when all the HC supply is completed becomes the predetermined HC amount. It is preferable to set the HC supply rate in each HC supply, the HC supply time in each HC supply, and the number of HC supplies.
- PM removal control of the exhaust emission control device of the first embodiment will be described.
- the same control as the normal PM removal control of the seventh embodiment is executed.
- the HC supply rate for each HC supply is set to be small, the HC supply time in one HC supply is set to be short, or the HC supply interval is set to be long. Therefore, the HC supplied from the HC supply valve 14 is likely to diffuse into the exhaust gas. For this reason, the formation of a region in which the air-fuel ratio is locally rich in the exhaust gas is suppressed, so that the release of S0 X from the S0 x trapping material 11 is reliably suppressed. .
- At least the HC supply rate in each HC supply, the HC supply time in each HC supply, the HC supply interval, and the number of HC supplies are at least the filter settings. It is set so that the temperature of 1 2 a can be raised to the PM combustion temperature.
- the total amount of HC supplied to the filter 12 a when all the HC supply is completed becomes the predetermined HC amount. It is preferable to set the HC supply rate in each HC supply, the HC supply time in each HC supply, and the number of HC supplies. In this case, the time during which S0 x release suppression and PM removal control are executed is longer than the time during which normal PM removal control is executed.
- the HC supply rate in each HC supply, the HC supply time in each HC supply, and the HC supply interval are controlled so as to be kept smaller than the temperature amplitude of the material 11. According to this, the HC supply rate for each HC supply is set to be smaller than that during normal PM removal control, or the HC supply time for each HC supply is set to be shorter, or the HC supply interval is set to be shorter. Set long. For this reason, HC supplied from the HC supply valve 14 is likely to diffuse into the exhaust gas. Therefore, the formation of a region in which the air-fuel ratio is locally rich in the exhaust gas is suppressed, so that the release of SOX from the SOX capture material 11 is reliably suppressed.
- the HC supply rate in each HC supply, the HC supply time in each HC supply, the HC supply interval, and the number of HC supply are at least It is set so that the temperature of the fill can be raised to the combustion temperature.
- the total HC amount supplied to the fill 12a when all the HC supply is completed is equal to the predetermined HC amount.
- PM removal control of the exhaust purification system of the thirteenth embodiment will be described.
- the PM removal condition is satisfied.
- the S0 x emission suppression condition is not satisfied, the same control as the normal PM removal control of the seventh embodiment is executed.
- the S O x release suppression / ⁇ ⁇ ⁇ removal control is executed.
- the lean degree of the air-fuel ratio of the exhaust gas supplied to the filter 12 a is normally maintained larger than the target lean degree in the ⁇ M removal control.
- the HC supply rate in each HC supply, the HC supply time in each HC supply, and the HC supply interval are controlled.
- the degree of leanness of the air-fuel ratio of the exhaust gas flowing into the fill 12a is small, the degree of leanness of the air-fuel ratio of the exhaust gas flowing into the S o capture material 11 is also small.
- a region in which the air-fuel ratio is locally rich may be formed in the exhaust gas flowing into the S O x trapping material 11.
- a region where the air-fuel ratio is locally rich is formed in the exhaust gas flowing into the S0 X trapping material 1 1. This suppresses the release of SOx from the SO x trapping material 1 1 with certainty.
- At least the HC supply rate in each HC supply, the HC supply time in each HC supply, the HC supply interval, and the number of HC supplies are at least filter 1 2 It is set so that the temperature of a can be raised to ⁇ ⁇ combustion temperature.
- the total HC amount supplied to the filter 12 a when all the HC supply is completed becomes the predetermined HC amount.
- the lean degree of the air-fuel ratio of the exhaust gas supplied to the fill 12a is, for example, in the exhaust pipe downstream of the fill 12a. Estimated from the output of the installed air-fuel ratio sensor.
- PM removal control of the exhaust purification system of the 14th embodiment will be described.
- the same control as the normal PM removal control of the seventh embodiment is executed when the PM removal condition is satisfied and the SOX release suppression condition is not satisfied.
- the S O x release suppression / ⁇ removal control is executed.
- the HC in each HC supply is set so that the temperature increase rate when the temperature of the filter 12 2 a is raised is kept smaller than the target temperature increase rate in the normal PM removal control. Control the supply rate, the HC supply time for each HC supply, and the HC supply interval. According to this, the HC supply rate in one HC supply is set small, the HC supply time in one HC supply is set short, or the HC supply interval is set long.
- HC supplied from the HC supply valve 14 is likely to diffuse into the exhaust gas. For this reason, since a region in which the air-fuel ratio is locally localized in the exhaust gas is suppressed, the release of SOx from the 30 trapping material 11 is reliably suppressed.
- the HC supply rate in each ⁇ C supply, the HC supply time in each HC supply, ⁇ C supply interval, and the number of HC supply are at least It is set so that the temperature of the fill can be raised to the combustion temperature.
- the HC supply rate in each HC supply the HC supply in each HC supply, so that the total amount of HC supplied to the Phil evening 12 a when all HC supply is completed becomes the above specified HC amount. It is preferable to set the time and the number of times of HC supply.
- FIG. 10 shows an example of a routine for executing PM removal control according to the embodiment of the present invention.
- the routine of Fig. 10 first, in step 20, whether or not the amount of particulate matter deposited on the fill 1 2 a ⁇ ⁇ ⁇ M is greater than the allowable value a ( ⁇ PM> r) (That is, whether ⁇ ⁇ removal condition is satisfied) is determined.
- a ⁇ PM> r
- the process proceeds to step 21 and the SOx trapping amount of SOX trapping material 11 is greater than the predetermined amount
- step 21 If it is determined in step 21 that ⁇ S ⁇ X>) 8, the process proceeds to step 22 to suppress the release of S ⁇ x in the seventh to 14th embodiments ⁇ PM Perform one of the removal controls. On the other hand, when it is determined in step 21 that ⁇ S ⁇ X ⁇ iS, the routine proceeds to step 23, where the S ⁇ x release suppression and PM removal control of the seventh to 14th embodiments described above is performed. Do one of the following:
- NO x absorbent 4 7 NO X is released from the HC supply valve 1 4
- SOX is released from the S0 x capture material 1 1. Therefore, as NOx release control of the exhaust purification device of the 15th embodiment, when NOx is to be released from the NO x absorbent 47 (that is, the NOx release condition is satisfied).
- FIG. 11 shows an example of a routine for executing the NO x release control of the 15th embodiment.
- the routine shown in Fig. 11 first, in step 30, whether the NO x amount ⁇ ⁇ absorbed in the NO X absorbent 4 7 is larger than the allowable value ⁇ ( ⁇ ⁇ ⁇ > ⁇ ). Or not (that is, whether or not the release condition is satisfied).
- the routine is terminated as it is.
- the process proceeds to step 3 1 where the temperature T sox of the 30 trapping material 1 1 is equal to or higher than the S ⁇ x release temperature T th (T so X ⁇ T th).
- step 31 If it is determined in step 31 that TsoX ⁇ Thh, the routine proceeds to step 32, and execution of NOx release control is prohibited. That is, in this case, NO X release control is not executed.
- step 3 1 if it is determined in step 3 1 that T so X ⁇ T th, the process proceeds to step 33, and the SOx trapping amount ⁇ S ⁇ X of the SO x trapping material 1 1 is greater than the predetermined amount j8. Or not ( ⁇ S ⁇ X> / 3) (that is, whether or not the SOX release suppression condition is satisfied).
- step 3 3 When it is determined in step 3 3 that ⁇ S0 X> jS, the process proceeds to step 3 4 to suppress SO x release in the above first to sixth embodiments ⁇ NO X release control Do one.
- step 33 when it is determined in step 33 that ⁇ S ⁇ X ⁇ ⁇ , the process proceeds to step 35 to execute one of the normal NO X release control of the first to sixth embodiments described above. To do.
- the following control may be adopted as the soot removal control of the exhaust purification system of the 16th embodiment. That is, as described above, during the execution of ⁇ ⁇ removal control, the temperature of the S ⁇ x trapping material 11 is relatively high.
- the temperature of the S ⁇ x trapping material 11 is SO x
- the temperature is higher than the discharge temperature, a region where the air-fuel ratio is locally rich is more reliably formed in the exhaust gas than when the temperature of the SO x trap 11 is lower than the S0 X release temperature. It should be suppressed. Therefore, in the PM removal control of the 16th embodiment, when the PM removal condition is satisfied and the SO x emission suppression condition is not satisfied, the normal PM removal control of the seventh to 14th embodiments described above is performed. Do one.
- the PM removal control of the 16th embodiment when the PM removal condition is satisfied and the S0 X emission suppression condition is satisfied, whether the temperature of the SO x trapping material 11 is higher than the SOX release temperature or not. Determine whether.
- the temperature of the SO x trapping material 11 is lower than the S0 X emission temperature, either the SOx emission suppression or PM removal control of the seventh embodiment to the 14th embodiment described above is performed. Execute.
- the SOx trapping suppression is performed when the temperature of the SOx trapping material 11 is lower than the SOx release temperature.
- the HC supply rate at this time is the HC in the SOX release suppression and ⁇ ⁇ removal control performed when the temperature of the SO x trapping material 11 is lower than the S0 x release temperature. Make it smaller than the supply rate. According to this, since the amount of HC supplied from the HC supply valve 14 is small in one HC supply, HC supplied from the HC supply valve 14 is likely to diffuse into the exhaust gas. For this reason, since a region in which the air-fuel ratio is locally rich in the exhaust gas is suppressed, the release of SOX from the S O x trapping material 11 is suppressed.
- the PM removal control of the first embodiment described above PM When the removal condition is satisfied and the S0 X emission suppression condition is satisfied, and the temperature of the SO x trapping material 1 1 is higher than the S0 X release temperature,
- the range in which the temperature rises or falls (temperature amplitude) is 30 ⁇ S o x emission suppression performed when the temperature of the trapping material 1 1 is lower than the SOX release temperature ⁇ SO x allowed in PM removal control
- the HC supply rate in each HC supply, the HC supply time in each HC supply, and the HC supply interval may be controlled so as to be kept smaller than the temperature amplitude of the trapping material 11.
- the HC supply rate in each HC supply is set smaller than that during the execution of SOX release suppression and PM removal control performed when the temperature of the SO x trapping material 1 1 is lower than the SOX release temperature,
- the HC supply time in each HC supply is set short, or the HC supply interval is set long. For this reason, HC supplied from the HC supply valve 14 diffuses into the exhaust gas. Therefore, it is possible to suppress the formation of a region where the air-fuel ratio is locally U-rich in the exhaust gas.
- FIG. 12 shows an example of a routine that executes the PM removal control of the 16th embodiment.
- the routine shown in Fig. 12 first, in step 40, whether or not the particulate matter deposited on the fill 12a is greater than the allowable value ( ⁇ PM> r) (ie It is determined whether the PM removal condition is satisfied.
- the routine is terminated as it is,
- step 4 1 When it is determined in step 4 1 that ⁇ S ⁇ X ⁇
- step 4 1 when it is determined in step 4 1 that ⁇ SOX>; 6, the process proceeds to step 4 2, where the temperature T sox of 30 trapping material 11 is equal to or higher than the SO x release temperature T th (T so It is determined whether or not X ⁇ T th).
- step 42 If it is determined in step 42 that T so X ⁇ T hh, the process proceeds to step 44 and S0 X release suppression / PM removal control I I is executed. In this S O x release suppression / ⁇ removal control I I, any of the S O X release suppression / PM removal control of the seventh to 14th embodiments is executed. On the other hand, when it is determined in step 42 that T s .o x ⁇ T hh, the process proceeds to step 45 and S O X emission suppression / ⁇ ⁇ removal control I is executed.
- the following control may be adopted as the NO X release control of the exhaust purification system of the 17th embodiment. That is, in the N 0 x release control of the 17th embodiment, the lean degree of the air-fuel ratio of the exhaust gas discharged from each cylinder is greater than a predetermined lean degree (hereinafter referred to as “predetermined lean degree”).
- predetermined lean degree a predetermined lean degree
- the NOx release condition is satisfied when the lean degree of the air-fuel ratio of the exhaust gas discharged from each cylinder is smaller than the predetermined lean degree
- the SOX emission suppression of the first to sixth embodiments ⁇ ⁇ Release Perform one of the controls.
- the release of S ⁇ X from the SOO X trapping material 11 is reliably suppressed. That is, when the lean degree of the air-fuel ratio of the exhaust gas discharged from each cylinder is smaller than the predetermined lean degree, the air-fuel ratio of the exhaust gas is close to the rich air-fuel ratio. At this time, if NO x release control is executed, there is a high possibility that a rich region where the air-fuel ratio is locally large in the exhaust gas flowing into the SO x trapping material 1 1 is formed. The temperature of the trapping material 1 1 is likely to be locally higher than the SOX release temperature.
- NOx release control when NOx release control is executed, it is ensured that SOX is released from the SOX capture material 1 1 when the lean degree of the air-fuel ratio of the exhaust gas discharged from each cylinder is smaller than the predetermined lean degree. In order to suppress this, it is possible to suppress the formation of a region where the air-fuel ratio is locally large and rich in the exhaust gas. Therefore, the temperature of the SO x trapping material 11 is locally higher than the SOX release temperature. It is necessary to suppress the rise. Therefore, in the NOX emission control of the 17th embodiment, when the lean degree of the air-fuel ratio of the exhaust gas discharged from each cylinder is smaller than the predetermined lean degree, the SOX of the first to sixth embodiments Release control ⁇ One of the NOX release controls is executed.
- the following control may be adopted as the PM removal control of the exhaust purification system of the 18th embodiment. That is, in the PM removal control of the 18th embodiment, when the lean degree of the air-fuel ratio of the exhaust gas discharged from each cylinder is larger than a predetermined lean degree (hereinafter referred to as “predetermined lean degree”), PM When the removal condition is satisfied, one of the normal PM removal control of the seventh embodiment to the 14th embodiment is executed. On the other hand, when the PM removal condition is satisfied when the lean degree of the air-fuel ratio of the exhaust gas discharged from each cylinder is smaller than the predetermined lean degree, the SOx release of the seventh to the 14th embodiments Suppress ⁇ Perform PM removal control.
- predetermined lean degree a predetermined lean degree
- the SO x of the seventh to 14th embodiment releases control ⁇ ⁇ ⁇ One of the removal control is executed.
- the soot removal control of the 18th embodiment is prohibited when the lean degree of the air-fuel ratio of the exhaust gas discharged from each cylinder is smaller than the predetermined lean degree. May be. This also reliably suppresses the release of SOx from the S O x trapping material 11.
- the NO X release control and PM removal control of the above-described embodiment can also be applied to the compression ignition type internal combustion engine shown in FIG.
- the internal combustion engine shown in FIG. 13 is the same as the internal combustion engine shown in FIG. 1, except that the internal combustion engine shown in FIG. Instead of the supported NO X catalyst 1 2, a particulate filter 12 a that simply collects particulate matter is disposed, and the NO x catalyst 1 2 is downstream of the particulate filter 1 2 a. It is in place. Then, in the internal combustion engine shown in Fig. 13, when trying to release NOX from the NO x absorbent of NO x catalyst 12, In the internal combustion engine shown in FIG. 13, when the particulate matter accumulated on the particulate filter 12 a is to be burned and removed, the internal combustion engine shown in FIG. The PM removal control of the embodiment described above is employed.
- the particulate filter 1 2 a includes a temperature sensor 2 2 for detecting the temperature of the particulate filter 1 2 a and the particulate filter 1 2 a.
- a differential pressure sensor 2 3 for detecting the front and rear differential pressure is attached.
- a temperature sensor 24 for detecting the temperature of the N0 x catalyst 12 is attached to the N0 x catalyst 1 2.
- the N O X release control and PM removal control of the above-described embodiment can also be applied to the compression ignition type internal combustion engine shown in FIG.
- the internal combustion engine shown in FIG. 14 is the same as the internal combustion engine shown in FIG. 1, but in the internal combustion engine shown in FIG. 14, the filter 1 2 a is carried downstream of the SOX trap 1 1. Instead of the NOX catalyst 1 2, a 1 ⁇ 0 catalyst 1 2 is arranged, and a particulate filter 1 2 a that simply collects particulate matter is arranged downstream of the NOX catalyst 1 2.
- the NOx release control of the embodiment described above is employed.
- the PM removal control of the above-described embodiment is adopted. Is done.
- an oxidation catalyst that oxidizes HC supplied into the exhaust gas from the HC supply valve 14 upstream of the SOO capture material 11.
- An oxidation catalyst 2 6 having an oxidation capacity higher than that of the SO x trapping material 1 1 may be disposed.
- HC supplied into the exhaust gas from the HC supply valve 14 is oxidized by the oxidation catalyst 26, a region in which the air-fuel ratio is locally rich is formed in the exhaust gas. This is surely suppressed.
- the HC supply valve 14 is provided with a heater for heating the HC supply valve 14, and the HC supply valve 1 is used in the normal NO X release control or the normal PM removal control.
- the HC supply valve 14 is not heated by the above-mentioned heating function, but HC is supplied in the S ⁇ X release control, N ⁇ X release control or SOX release control, ⁇ ⁇ removal control.
- the HC supply valve 14 may be heated by heat.
- HC supplied from the HC supply valve 14 is easily diffused into the exhaust gas in the suppression of SO x release ⁇ NO X release control or SOX release ⁇ ⁇ ⁇ removal control.
- the release of S ⁇ X from the trapping material 1 1 is suppressed.
- the pressure for supplying HC into the exhaust gas from the HC supply valve 14 in the S0 x release suppression ⁇ ⁇ ⁇ release control or SOX release control ⁇ PM removal control is normally NO X release.
- the pressure may be higher than the pressure at which HC is supplied from the HC supply valve 14 into the exhaust gas. This also suppresses SOX release ⁇ N ⁇ x release control or SO x release control, PM removal control, because HC supplied from the HC supply valve 14 diffuses into the exhaust gas. Release of SO x from the material 11 is suppressed.
- an HC supply valve that includes a plurality of supply holes for supplying HC and can appropriately change the number of supply holes for supplying HC is adopted.
- S ⁇ x emission suppression ⁇ ⁇ ⁇ emission control or SO x emission suppression ⁇ PM removal control When supplying HC into the exhaust gas from the HC supply valve, even if the number of supply holes for supplying HC is larger than the number of supply holes for supplying HC in normal NOX release control or normal PM removal control Good.
- NO X release controls of the above-described embodiments may be combined within a range where no contradiction occurs, or some of the PM removal controls of the above-described embodiments are combined within a range where no contradiction occurs. It's okay.
- the NO X release control or PM removal control of the second embodiment, the third embodiment, the eighth embodiment, and the ninth embodiment other than the above-described one is the HC supply valve 1
- the present invention is also applicable to an internal combustion engine that injects fuel from the fuel injection valve 3 during the latter half of the expansion stroke of a specific cylinder or during the exhaust stroke, instead of supplying HC into the exhaust gas from 4.
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Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
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EP07790450A EP2039900B1 (en) | 2006-06-30 | 2007-06-29 | Exhaust gas purifier for internal combustion engine |
CN2007800250024A CN101484670B (zh) | 2006-06-30 | 2007-06-29 | 内燃机的排气净化装置 |
US12/227,718 US20090249768A1 (en) | 2006-06-30 | 2007-06-29 | Exhaust Purification System of Internal Combustion Engine |
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JP2006-181380 | 2006-06-30 | ||
JP2006181380A JP4404073B2 (ja) | 2006-06-30 | 2006-06-30 | 内燃機関の排気浄化装置 |
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PCT/JP2007/063508 WO2008001950A1 (fr) | 2006-06-30 | 2007-06-29 | Purificateur de gaz d'échappement pour moteur à combustion interne |
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US (1) | US20090249768A1 (ja) |
EP (1) | EP2039900B1 (ja) |
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ES2629430T3 (es) | 2010-12-24 | 2017-08-09 | Toyota Jidosha Kabushiki Kaisha | Sistema de purificación de gases de escape para motor de combustión interna |
CN102753794B (zh) | 2011-02-07 | 2015-05-13 | 丰田自动车株式会社 | 内燃机的排气净化装置 |
EP2503120B1 (en) | 2011-02-10 | 2016-09-14 | Toyota Jidosha Kabushiki Kaisha | Nox purification method of an exhaust-gas purifying system for internal-combustion engine |
CN103502590B (zh) | 2011-03-17 | 2016-03-16 | 丰田自动车株式会社 | 内燃机的排气净化装置 |
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JP2004360575A (ja) * | 2003-06-04 | 2004-12-24 | Toyota Motor Corp | 内燃機関の排気浄化システム |
JP2005273573A (ja) * | 2004-03-25 | 2005-10-06 | Toyota Motor Corp | 内燃機関の排気浄化装置 |
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WO1998048153A1 (fr) * | 1997-04-24 | 1998-10-29 | Toyota Jidosha Kabushiki Kaisha | Systeme de gestion d'emissions d'echappement pour moteurs a combustion interne |
DE10001432A1 (de) * | 2000-01-15 | 2001-08-16 | Volkswagen Ag | Verfahren und Vorrichtung zur Steuerung einer Entschwefelung eines in einem Abgaskanal einer Verbrennungskraftmaschine angeordneten NO¶x¶-Speicherkatalysators |
JP3645841B2 (ja) * | 2001-08-28 | 2005-05-11 | 本田技研工業株式会社 | 内燃機関の排気浄化装置 |
JP4083453B2 (ja) * | 2002-03-29 | 2008-04-30 | いすゞ自動車株式会社 | NOx浄化システム及びその触媒劣化回復方法 |
JP3867612B2 (ja) * | 2002-04-12 | 2007-01-10 | トヨタ自動車株式会社 | 内燃機関の空燃比制御装置 |
JP3945335B2 (ja) * | 2002-07-31 | 2007-07-18 | トヨタ自動車株式会社 | 内燃機関の排気浄化装置 |
WO2004025091A1 (ja) * | 2002-09-10 | 2004-03-25 | Toyota Jidosha Kabushiki Kaisha | 内燃機関の排気浄化装置 |
JP2004339993A (ja) * | 2003-05-14 | 2004-12-02 | Toyota Motor Corp | 内燃機関の排気浄化システム |
JP3938136B2 (ja) * | 2003-10-29 | 2007-06-27 | トヨタ自動車株式会社 | 圧縮着火式内燃機関の排気浄化装置 |
-
2006
- 2006-06-30 JP JP2006181380A patent/JP4404073B2/ja not_active Expired - Fee Related
-
2007
- 2007-06-29 WO PCT/JP2007/063508 patent/WO2008001950A1/ja active Application Filing
- 2007-06-29 EP EP07790450A patent/EP2039900B1/en not_active Expired - Fee Related
- 2007-06-29 CN CN2007800250024A patent/CN101484670B/zh not_active Expired - Fee Related
- 2007-06-29 US US12/227,718 patent/US20090249768A1/en not_active Abandoned
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JPH06173652A (ja) | 1992-12-03 | 1994-06-21 | Toyota Motor Corp | 内燃機関の排気浄化装置 |
JPH09122443A (ja) * | 1995-11-08 | 1997-05-13 | Toyota Motor Corp | ディーゼル機関の排気ガス浄化方法 |
JP2000018021A (ja) * | 1998-07-03 | 2000-01-18 | Toyota Motor Corp | 内燃機関の排気浄化装置 |
JP2004360575A (ja) * | 2003-06-04 | 2004-12-24 | Toyota Motor Corp | 内燃機関の排気浄化システム |
JP2005273573A (ja) * | 2004-03-25 | 2005-10-06 | Toyota Motor Corp | 内燃機関の排気浄化装置 |
Non-Patent Citations (1)
Title |
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See also references of EP2039900A4 |
Also Published As
Publication number | Publication date |
---|---|
EP2039900A4 (en) | 2010-11-24 |
CN101484670B (zh) | 2011-09-28 |
JP2008008249A (ja) | 2008-01-17 |
CN101484670A (zh) | 2009-07-15 |
JP4404073B2 (ja) | 2010-01-27 |
EP2039900B1 (en) | 2012-01-25 |
US20090249768A1 (en) | 2009-10-08 |
EP2039900A1 (en) | 2009-03-25 |
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