WO2007015478A1 - 排気浄化装置 - Google Patents
排気浄化装置 Download PDFInfo
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- WO2007015478A1 WO2007015478A1 PCT/JP2006/315193 JP2006315193W WO2007015478A1 WO 2007015478 A1 WO2007015478 A1 WO 2007015478A1 JP 2006315193 W JP2006315193 W JP 2006315193W WO 2007015478 A1 WO2007015478 A1 WO 2007015478A1
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- temperature
- storage catalyst
- nox storage
- supply
- nox
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
- B01D53/9404—Removing only nitrogen compounds
- B01D53/9409—Nitrogen oxides
- B01D53/9431—Processes characterised by a specific device
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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
- F01N13/0097—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series the purifying devices are arranged in a single housing
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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
- F01N3/0821—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents combined with particulate filters
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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
- F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
- F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
- F01N3/2006—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating
- F01N3/2033—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating using a fuel burner or introducing fuel into exhaust duct
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- 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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- 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
- F01N2260/00—Exhaust treating devices having provisions not otherwise provided for
- F01N2260/14—Exhaust treating devices having provisions not otherwise provided for for modifying or adapting flow area or back-pressure
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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
- F01N2410/00—By-passing, at least partially, exhaust from inlet to outlet of apparatus, to atmosphere or to other device
- F01N2410/12—By-passing, at least partially, exhaust from inlet to outlet of apparatus, to atmosphere or to other device in case of absorption, adsorption or desorption of exhaust gas constituents
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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
- F02B29/00—Engines characterised by provision for charging or scavenging not provided for in groups F02B25/00, F02B27/00 or F02B33/00 - F02B39/00; Details thereof
- F02B29/04—Cooling of air intake supply
- F02B29/0406—Layout of the intake air cooling or coolant circuit
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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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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D9/00—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits
- F02D9/04—Controlling engines by throttling air or fuel-and-air induction conduits or exhaust conduits concerning exhaust conduits
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
- F02M26/02—EGR systems specially adapted for supercharged engines
- F02M26/04—EGR systems specially adapted for supercharged engines with a single turbocharger
- F02M26/05—High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
- F02M26/02—EGR systems specially adapted for supercharged engines
- F02M26/09—Constructional details, e.g. structural combinations of EGR systems and supercharger systems; Arrangement of the EGR and supercharger systems with respect to the engine
- F02M26/10—Constructional details, e.g. structural combinations of EGR systems and supercharger systems; Arrangement of the EGR and supercharger systems with respect to the engine having means to increase the pressure difference between the exhaust and intake system, e.g. venturis, variable geometry turbines, check valves using pressure pulsations or throttles in the air intake or exhaust system
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
- F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
- F02M26/14—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories in relation to the exhaust system
- F02M26/15—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories in relation to the exhaust system in relation to engine exhaust purifying apparatus
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
Definitions
- the present invention relates to an exhaust purification device for purifying engine exhaust, and more particularly to an exhaust purification device provided with a NOx storage catalyst.
- NOx (nitrogen oxides) in exhaust gas is stored in an oxygen atmosphere, and NOx storage catalyst that releases and reduces the stored NOx in a reducing atmosphere is placed in the exhaust passage of the engine.
- An exhaust gas purification device that is provided and purifies NOx in the exhaust gas is known.
- fuel components and engine lubricating oil contain xio components, and these xio components become SOx (sulfur oxides) and are discharged together with engine exhaust.
- SOx sulfur oxides
- This SOx is also stored in the NOx storage catalyst by the same mechanism as NOx, and so-called poisoning occurs in which the NOx storage capacity decreases as the storage amount of SOx increases.
- Patent Document 1 It is known to supply (hydrocarbon) to raise the temperature of the NOx storage catalyst and make it a reducing atmosphere (hereinafter referred to as a rich spike), and the execution of such S purge is disclosed in, for example, Japanese Patent Laid-Open No. 2004-251172 It is disclosed in a gazette (hereinafter referred to as Patent Document 1).
- the NOx storage catalyst is supported on the particulate filter, and when the S purge is resumed after being interrupted, the temperature is raised to regenerate the particulate filter. After that, the temperature is further raised and S purge is performed. Even when the temperature of the NOx storage catalyst is raised stepwise in this way, it is necessary to raise the exhaust temperature to around 600 ° C in order to regenerate the particulate filter.
- the HC supplied by the rich spike burns rapidly on the catalyst that has become hot, causing an excessive temperature rise, and maintaining an appropriate amount of HC required for S purge in the exhaust gas It becomes difficult.
- the present invention has been made in view of such problems, and the object of the present invention is to stably recover the NO X storage catalyst without poisoning without overheating the NOx storage catalyst.
- an object of the present invention is to provide an exhaust purification device that can be efficiently performed.
- an exhaust emission control device of the present invention is provided in an exhaust passage of an engine and occludes NOx in exhaust gas in an oxygen atmosphere and occludes in a reducing atmosphere.
- NOx storage catalyst that releases and reduces NOx
- HC supply means that supplies HC into the exhaust gas flowing into the NOx storage catalyst
- HC supply means force HC supply to raise the temperature of the NOx storage catalyst
- the control means includes the control means for performing the S purge of the NOx storage catalyst by performing HC supply by rich snooping to form a reducing atmosphere and the control means includes the HC supply means By controlling the temperature of the NOx storage catalyst, the temperature of the NOx storage catalyst is raised to a second temperature obtained by subtracting the temperature increase caused by the first rich spike as a temperature required for the S purge.
- the first temperature power NOx occlusion determined in advance as the temperature for recovering the poisoning prior to the start of the S purge of the NOx occlusion catalyst by the rich spike.
- the amount of HC required to maintain the NOx storage catalyst at the second temperature minus the temperature rise due to rich snooping to make the catalyst into a reducing atmosphere is supplied to the exhaust gas flowing into the NOx storage catalyst. Therefore, even after the start of the supply of HC for making the NOx storage catalyst into a reducing atmosphere, even if the exhaust gas still contains a large amount of oxygen, the reaction of the supplied HC and oxygen causes a NOx storage catalyst. Does not overheat
- the first temperature force continues to supply the amount of HC necessary to raise the NOx storage catalyst to the second temperature minus the temperature increase due to the rich sneak for making the NOx storage catalyst into a reducing atmosphere. While doing this, add S to the HC supply and add HC necessary for the rich spike to make the NOx storage catalyst a reducing atmosphere and perform S purge. Therefore, it becomes easy to maintain the temperature of the NOx occlusion catalyst at the first temperature, which is a temperature for recovering the Xo poisoning, during execution of the S purge by the rich spike.
- FIG. 1 is an overall configuration diagram of an exhaust emission control device according to an embodiment of the present invention
- FIG. 2 is a flowchart of S purge control performed in the exhaust gas purification device of FIG. 1, and
- FIG. 3 is a diagram showing temporal changes of the HC supply amount, the excess air ratio of the exhaust gas flowing into the NOx storage catalyst, and the exhaust gas temperature on the outlet side of the NOx storage catalyst when the S purge control of FIG. 2 is executed. is there.
- FIG. 1 is a system configuration diagram of a four-cylinder diesel engine (hereinafter referred to as an engine) to which an exhaust purification system according to an embodiment of the present invention is applied.
- the present invention is based on FIG. The configuration of the exhaust emission control device will be described.
- the engine 1 includes a high-pressure accumulator chamber (hereinafter referred to as a common rail) 2 common to each cylinder, and light oil, which is high-pressure fuel supplied from a fuel injection pump (not shown) and stored in the common rail 2, Supplied to each injector 4 provided in each cylinder, and from each injector 4 Light oil is injected into each cylinder.
- a high-pressure accumulator chamber hereinafter referred to as a common rail
- light oil which is high-pressure fuel supplied from a fuel injection pump (not shown) and stored in the common rail 2, Supplied to each injector 4 provided in each cylinder, and from each injector 4 Light oil is injected into each cylinder.
- the intake passage 6 is equipped with a turbocharger 8, and intake air drawn from an air cleaner (not shown) flows into the compressor 8a of the turbocharger 8 from the intake passage 6 and is supercharged by the compressor 8a. Is introduced into the intake manifold 14 via the intercooler 10 and the intake control valve 12. Further, an intake flow rate sensor 16 for detecting the intake air flow rate to the engine 1 is provided upstream of the compressor 8a in the intake passage 6.
- an exhaust port (not shown) through which exhaust is discharged from each cylinder of the engine 1 is connected to an exhaust pipe (exhaust passage) 20 via an exhaust manifold 18.
- An EGR passage 24 is provided between the exhaust mold 18 and the intake manifold 14 for communicating the exhaust manifold 18 and the intake manifold 14 via the EGR valve 22.
- the exhaust pipe 20 passes through the turbine 8 b of the turbocharger 8 and is connected to the exhaust aftertreatment device 28 via the exhaust throttle valve 26. Further, the rotating shaft of the turbine 8b is connected to the rotating shaft of the compressor 8a, and the turbine 8b receives the exhaust flowing in the exhaust pipe 20 and drives the compressor 8a.
- the exhaust aftertreatment device 28 includes an upstream casing 30 and a downstream casing 34 communicated with the downstream side of the upstream casing 30 through a communication path 32.
- a NOx storage catalyst 36 is accommodated, and a particulate filter (hereinafter referred to as a filter) 38 is accommodated on the downstream side of the NOx storage catalyst 36.
- a filter 38 is accommodated on the downstream side of the NOx storage catalyst 36.
- This NOx storage catalyst 36 stores NOx in the exhaust when it is in an acidic atmosphere where the oxygen concentration in the inflowing exhaust gas is high, and the oxygen concentration in the inflowing exhaust gas is low so that HC and CO (— Reducing component power such as acid (carbon) S Stores in the reducing atmosphere contained in the exhaust gas N
- the filter 38 has a Hercam type ceramic carrier force, and a large number of passages communicating the upstream side and the downstream side are arranged side by side, and the upstream side opening and the downstream side opening of the passage are alternately closed.
- the exhaust of the engine 1 is reduced by collecting the particulates in the exhaust.
- NOx occlusion catalyst 36 The NOx occlusion amount exceeds the limit amount and is no longer occluded. NOx flows into the filter 38 and acts as an oxidant for the particulates trapped and deposited in the filter 38. That is, the NOx that flows into the filter 38 oxidizes the particulates and removes them from the filter 38, continuously regenerates the filter 38 and becomes N in the atmosphere.
- an exhaust temperature sensor 40 for detecting the outlet side exhaust temperature Tc of the NOx storage catalyst 36 is provided downstream of the NOx storage catalyst 36. Further, before and after the filter 38, an upstream pressure sensor 42 for detecting the exhaust pressure upstream of the filter 38 and a downstream pressure sensor 44 for detecting the exhaust pressure downstream of the filter 38 are provided.
- a downstream oxidation catalyst 46 is accommodated in the downstream casing 34.
- the post-stage oxidation catalyst 46 has a function of oxidizing HC and CO remaining in the exhaust gas without being purified by the NOx storage catalyst 36.
- the post-stage oxidation catalyst 46 oxidizes this HC and the particulates are incinerated by the forced regeneration of the filter 38. CO generated during
- An addition valve (HC supply means) 48 is provided. By injecting fuel from the fuel addition valve 48 into the exhaust gas flowing into the NOx storage catalyst 36, the NOx storage catalyst 38 is brought into a reducing atmosphere. Thereby, NOx stored in the NOx storage catalyst 38 is released and reduced.
- the ECU (control means) 50 is a control device for performing comprehensive control including the operation control of the engine 1.
- the ECU (control means) 50 is also configured with power such as a CPU, a memory, a timer counter, and can calculate various control amounts. At the same time, various devices are controlled based on the control amount.
- ECU 50 On the input side of the ECU 50, in order to collect information necessary for various controls, in addition to the intake flow sensor 16, exhaust temperature sensor 40, upstream pressure sensor 42, and downstream pressure sensor 44 described above, engine rotation is performed. Various sensors, such as a rotation speed sensor 52 for detecting the number and an accelerator opening sensor 54 for detecting the depression amount of the accelerator pedal, are connected. Also ECU Connected to the output side of 50 are various devices such as the indicator 4, intake control valve 12, EGR valve 22, exhaust throttle valve 26, and fuel addition valve 48 for each cylinder that is controlled based on the calculated control amount. Has been.
- the ECU 50 also performs calculation of the fuel supply amount to each cylinder of the engine 1 and fuel supply control from the injector 4 based on the calculated fuel supply amount.
- the fuel supply amount (main injection amount) necessary for the operation of the engine 1 is stored in advance based on the engine speed detected by the speed sensor 52 and the accelerator position detected by the accelerator position sensor 54.
- the map power that is present is also read and determined.
- the amount of fuel supplied to each cylinder is adjusted according to the valve opening time of the indicator 4, and each injector 4 is driven to open during the driving time corresponding to the determined fuel amount, and main injection is performed to each cylinder. As a result, the amount of fuel required to operate the engine 1 is supplied.
- the ECU 50 also performs control for forcibly regenerating the filter 38. Particulates deposited on the filter 38 are removed by oxidation through continuous regeneration through reaction with NO flowing through the NOx storage catalyst 36 and flowing into the filter 38 as described above.
- the accumulated particulates may not be sufficiently removed by oxidation. If this condition continues, excessive particulates may accumulate in the filter 38 and the filter 38 may be clogged. For this reason, the filter 38 is forcedly regenerated appropriately according to the particulate accumulation state in the filter 38. Is done.
- the exhaust temperature is raised by controlling the intake control valve 12 and the exhaust throttle valve 26 in the closing direction, and fuel is injected into the exhaust from the fuel addition valve 48, and the particulates are reduced.
- the temperature of the filter 38 is raised to a temperature that can be incinerated. That is, the HC supplied by the fuel addition valve 48 reaches the NOx storage catalyst 36, and high-temperature exhaust gas whose temperature has further increased due to the oxidation reaction of HC in the NOx storage catalyst 36 flows into the filter 38.
- the particulates deposited on the filter 38 are incinerated by the exhaust gas that has become high in this way, and the filter 38 is forcibly regenerated.
- the ECU 50 also performs control for appropriately performing NOx purification by the NOx storage catalyst 36.
- Engine 1 is a diesel engine, and lean combustion is performed in most of the operating range, and the oxygen concentration in the exhaust gas becomes high, and NOx in the exhaust gas is stored in the NOx storage catalyst 36. If the state in which the NOx storage catalyst 36 stores NOx in the exhaust gas continues for a long time, the NOx storage capacity of the NOx storage catalyst 36 is saturated, and the NOx in the exhaust gas is not stored in the NOx storage catalyst 36 and remains as it is. May be released into the atmosphere.
- the ECU 50 controls the fuel addition valve 48 to supply HC by, for example, injecting fuel into the exhaust gas every predetermined time to supply the NOx storage catalyst.
- 36 is used as a reducing atmosphere, and NOx occluded in the NOx occlusion catalyst 36 is released and reduced.
- the Xo component is contained in the fuel and the lubricating oil of the engine 1, and this Xo component becomes SOx and the engine 1 power is also reduced. It is discharged with the exhaust. SOx contained in the exhaust gas is stored in the NOx storage catalyst 36 by the same mechanism as NOx, so the NOx storage capacity of the NOx storage catalyst 36 decreases as the storage amount of SOx increases. Poisoning occurs. Even if this Xo poisoning is left unattended, the NOx purification efficiency by the NOx storage catalyst 36 is reduced, and NOx in the exhaust gas may be released into the atmosphere without being stored in the NOx storage catalyst 36. There is.
- the SOx storage amount of the NOx storage catalyst 36 is estimated according to the fuel consumption of the engine 1 and the operation time, etc., and when this estimated SOx storage amount exceeds a predetermined value, the control for the S purge is performed by the ECU 50. Done. In the control of the S purge, it is necessary to raise the temperature of the NOx storage catalyst 36 to around 700 ° C and make the NOx storage catalyst 36 into a reducing atmosphere.
- Such an S purge control routine is determined by the other S purge control necessity determination routine (not shown) that the estimated SOx occlusion amount is equal to or greater than the predetermined value as described above and the S purge is necessary. Is started at a predetermined control cycle according to the flowchart shown in FIG. [0039]
- step S2 it is determined whether or not the value of the flag F1 is 1.
- the flag F1 is a flag indicating whether or not HC supply by rich spike for the S purge may be performed. When the value is 1, rich snooke is permitted.
- the initial value of flag F1 is 0, and the control proceeds to step S4 in the first control cycle when the S purge control is started.
- step S4 it is determined whether or not the value of the flag Fa is 1.
- the flag Fa is a flag indicating whether or not the timer A, which will be described later, has started counting, and indicates that when the value is 1, the timer A starts counting. Since the initial value of the flag Fa is 0, the process proceeds to step S6.
- step S6 the timer A starts counting, and in the next step S8, the value of the flag Fa is set to 1 in accordance with the start of the timer A power count.
- next step S 10 it is determined whether or not the outlet side exhaust gas temperature Tc of the NOx storage catalyst 36 detected by the exhaust gas temperature sensor 40 is equal to or higher than a predetermined temperature T2.
- the predetermined temperature T2 is obtained by subtracting the temperature increase expected when the HC supply is performed by the rich spike described later from the temperature required for the S purge (first temperature) as the temperature of the NOx storage catalyst 36. This corresponds to the exhaust gas temperature on the outlet side of the NOx storage catalyst 36 at the temperature (second temperature). Therefore, when it is determined in step S10 that the outlet side exhaust temperature Tc of the NOx storage catalyst 36 is equal to or higher than the predetermined temperature T2, it is determined that the temperature of the NOx storage catalyst 36 is equal to or higher than the second temperature.
- the first temperature is a temperature necessary for performing the S purge, and is set to be several tens of degrees C higher than the lower limit temperature at which the S purge of the NOx storage catalyst 36 can be performed.
- the second temperature is set to an appropriate value according to the characteristics of the NOx storage catalyst 36 and the engine 1. In the present embodiment, for example, the first temperature is set to 700 ° C and the second temperature is set to 500 ° C.
- step S10 Based on the comparison result between the exhaust temperature Tc at the outlet side of the NOx storage catalyst 36 detected by the exhaust temperature sensor 40 and the predetermined temperature T2, the temperature of the NOx storage catalyst 36 has not reached the second temperature in step S10. If it is determined that the temperature is higher than the second temperature, the process proceeds to step S12.
- step S12 and step S14 the engine speed detected by the rotational speed sensor 52 is detected.
- the fuel addition valve 48 opens and closes so that the pre-stored map force is supplied to the HC power exhaust of the read supply amount based on the number and the accelerator pedal depression amount detected by the accelerator opening sensor 54. Be controlled.
- the HC supply amount necessary for raising the NOx storage catalyst 36 to the second temperature is set in the map, and when the processing proceeds to step S12, the temperature of the NOx storage catalyst 36 is Since the second temperature has not been reached, an increase map with a relatively large HC supply is used.
- step S14 since the temperature of the NOx storage catalyst 36 is equal to or higher than the second temperature, a reduction map in which the HC supply amount is set to be relatively small is used.
- step S16 it is determined whether or not the timer A count time ta started counting in step S6 has reached a predetermined time tl. In the initial stage of control start of the S purge, the count time ta has not reached the predetermined time tl, and this time the control cycle ends.
- step S2 since the value of the flag F1 is still 0, the process proceeds from step S2 to step S4. Since the value of the flag Fa has already been set to 1, the process directly proceeds from step S4 to step S10. The process will proceed.
- step S10 it is determined whether or not the outlet side exhaust gas temperature Tc of the NOx storage catalyst 36 is equal to or higher than the predetermined temperature T2, whereby the temperature of the NOx storage catalyst 36 is set to the second temperature. It is determined whether or not the temperature is higher.
- HC supply is performed using the increase map in step S12, and the temperature of the NOx storage catalyst 36 is set to the second temperature. If it is determined that the temperature is higher than the temperature, in step S14, HC is supplied using the weight loss map.
- step S12 or step S14 is repeatedly performed at each control cycle, whereby the temperature of the NOx storage catalyst 36 is raised to the second temperature or in the vicinity thereof.
- Fig. 5 shows how the HC supply amount from the fuel addition valve 48 at this time, the excess air ratio of the exhaust gas supplied to the NOx storage catalyst 36, and the exhaust gas temperature on the outlet side of the NOx storage catalyst 36 change over time. Shown in 3.
- HC is supplied in step S12 or step S14 in FIG. 2, but for a while, the outlet side exhaust temperature Tc of the NOx storage catalyst 36 becomes the predetermined temperature T2. HC supply using the increase map in step S12 will be performed.
- the excess air ratio of the exhaust gas flowing into the NOx storage catalyst 36 at this time is reduced by the HC supply in step S12 or step S14, and the oxygen concentration is lowered before the start of control, but is still oxidized. In the atmosphere.
- step S16 the count time ta of the timer A has exceeded the predetermined time tl
- the process is Proceeding to step S18 to set the value of flag F1 to 1, the control cycle is ended.
- step S12 or step S14 reacts with the oxygen on the catalyst, so that the NOx storage catalyst 36 has a local concentration.
- the HC supplied at this time is just enough to raise the temperature of the NOx storage catalyst 36 to the second temperature, and HC supply by rich spike is not performed. The temperature does not rise so high that the NOx storage catalyst 36 overheats.
- the locally raised temperature is made uniform over the entire NOx storage catalyst 36 over time.
- the predetermined time tl is set so as to ensure a period necessary for such a uniform temperature. Therefore, as described above, until the predetermined time tl after the start of the S purge control, only the HC supply by the step S12 or the step S14 is performed, and the HC supply by the rich spike is not performed. While the NOx storage catalyst 36 is heated to around the second temperature, the temperature power NOx storage catalyst 36 that has risen locally is made uniform throughout.
- step S18 the value of the flag F1 is set to 1, and in the control cycle after HC supply by rich spike is permitted, the process proceeds from step S2 to step S20.
- step S20 it is determined whether or not the value of the flag Fb is 1.
- the flag Fb is a flag indicating whether or not the timer B, which will be described later, has started counting. When the flag Fb is 1, it indicates that the timer B has started counting. Since the initial value of the flag Fb is 0, the process proceeds to step S22.
- step S22 the timer B starts counting, and in the next step S24, the value of the flag Fb is set to 1 in accordance with the start of timer B counting.
- next step S26 it is determined whether or not the outlet side exhaust temperature Tc of the NOx storage catalyst 36 detected by the exhaust temperature sensor 40 is equal to or higher than a predetermined temperature T1.
- the predetermined temperature T1 corresponds to the exhaust gas temperature on the outlet side of the NOx storage catalyst 36 when the temperature force S of the NOx storage catalyst 36 is at the first temperature that is a temperature necessary for the purge. Therefore, if it is determined in step S26 that the outlet side exhaust temperature Tc of the NOx storage catalyst 36 is equal to or higher than the predetermined temperature T1, it is determined that the temperature of the NOx storage catalyst 36 is equal to or higher than the first temperature. become.
- step S30 Based on the comparison result between the exhaust temperature Tc at the outlet side of the NOx storage catalyst 36 detected by the exhaust temperature sensor 40 and the predetermined temperature T1, the temperature of the NOx storage catalyst 36 does not reach the first temperature in step S26. If it is determined, the process proceeds to step S28, and if it is determined that the temperature is equal to or higher than the first temperature, the process proceeds to step S30.
- step S28 and step S30 based on the engine speed detected by the speed sensor 52, the amount of depression of the accelerator pedal detected by the accelerator opening sensor 54, etc., in step S12 or step S14, Supply amount of HC that also reads the map power used
- the fuel addition valve 48 is controlled to be opened and closed so as to be supplied into the force S exhaust.
- the temperature increase of the NOx storage catalyst 36 has not reached the first temperature, so the increase map is used.
- step S30 the NOx storage catalyst 36 has a temperature equal to or higher than the first temperature, and thus a weight reduction map is used.
- step S32 HC is supplied from the fuel addition valve 48 by rich spike.
- This rich spike is added to the HC supply in step S28 or step S30, and the HC supply is performed by opening the fuel addition valve 48 only during a predetermined period. It is changed according to the operating condition of 1.
- HC supply by rich spike is performed when the control cycle corresponds to the timing of performing rich spike, instead of performing HC supply by rich spike every time in step S32 in each control cycle. It is like that.
- step S28 or step S30 Since the amount of HC required to raise the NOx storage catalyst 36 to the second temperature is supplied in step S28 or step S30, if HC supply by rich spike is performed in step S32, The temperature of the NOx storage catalyst 36 further rises from the second temperature due to the acid-oxidation reaction of the supplied HC, and the NOx storage catalyst 36 becomes a reducing atmosphere.
- step S34 it is determined whether or not the force is such that the count time tb of the timer B started counting in step S22 is equal to or greater than the predetermined time t2.
- This predetermined time tb is set as a time during which rich poisoning can sufficiently recover the NO poisoning of the NOx storage catalyst 36, and the count time tb of timer B reaches the predetermined time t2. If not, the control cycle is terminated after the determination in step S34.
- step S20 determine whether or not the value of the flag Fb is 1. Since the value of flag Fb is set to 1 in step S24 when timer B starts counting, the process proceeds directly from step S20 to step S26 this time.
- step S26 by determining whether or not the outlet side exhaust temperature Tc of the NOx storage catalyst 36 is equal to or higher than the predetermined temperature T1, the temperature of the NOx storage catalyst 36 is changed to the first temperature. It is determined whether this is the case. [0073] Then, if it is determined that the temperature of the NOx storage catalyst 36 has not reached the first temperature, HC supply using the increase map is performed in step S28, and the temperature of the NOx storage catalyst 36 is set to the first temperature. If it is determined that this is the case, HC supply using the weight loss map is performed in step S30.
- HC is supplied by rich spike.
- the supply amount of HC supplied in step S28 or step S30 is set based on the map used in step S12 or step S14, and the temperature of the NO X storage catalyst 36 is set to the second temperature as described above.
- the amount required to raise the temperature is a temperature obtained by subtracting the temperature rise expected when HC is supplied by Richsno ⁇ Ick from the first temperature that is the temperature necessary for S purge, step S28 or
- the temperature of the NOx storage catalyst 36 is maintained around the first temperature required for the S purge.
- the temperature adjustment of the NOx storage catalyst 36 is performed by considering the increase in the temperature of the NOx storage catalyst 36 due to the rich spike, and the HC supply and step by the increase map in step S28. Since this is performed by switching between the HC supply based on the reduction map in S30, the temperature of the NOx storage catalyst 36 can be easily maintained at the first temperature.
- FIG. 3 shows the time of each of the HC supply amount from the fuel addition valve 48 at this time, the excess air ratio of the exhaust gas supplied to the NOx storage catalyst 36, and the outlet side exhaust temperature of the NOx storage catalyst 36. The state of the change is shown.
- the HC supply force by the rich spike in step S32 is performed in a form added to the HC supply by step S28 or step S30.
- the exhaust gas temperature Tc on the outlet side of the NOx storage catalyst 36 is maintained around the predetermined temperature T1, and the temperature of the NOx storage catalyst 36 is maintained around the first temperature required for the S purge. .
- the excess air ratio of the NOx storage catalyst 36 is temporarily greatly reduced by the HC supplied by the rich spike when the rich spike is performed, and the oxygen concentration is reduced to reduce the reducing atmosphere. It becomes. As a result, the SOx stored in the NOx storage catalyst 36 is released and the NO poisoning of the NOx storage catalyst 36 is recovered.
- step S36 all the values of the flags Fl, Fa, and Fb used in the control of the S purge are set to 0. Further, in step S38, the timer A and the timer B are reset to complete the control cycle, and not shown. The S purge control routine is terminated by the S purge necessity determination routine.
- the control for the S purge is started and the HC is supplied by a rich spike for a predetermined time tl. Therefore, the temperature is made uniform throughout the NOx storage catalyst 36. Due to this uniform temperature, the NOx storage catalyst 36 will not be overheated even if HC is supplied by rich noise thereafter.
- the fuel addition valve 48 is used as the HC supply means.
- a fuel addition valve 48 is not provided, and the exhaust gas is exhausted by post-injection after main injection for each cylinder of the engine 1. You may make it supply HC.
- the injector 4 provided in each cylinder corresponds to the HC supply means of the present invention.
- the temperature at which the NOx catalyst 36 has reached the first temperature or the second temperature is reduced.
- the inlet portion of the NOx storage catalyst 36 or the inside thereof It is superior to those that detect temperatures at other locations in that it is less susceptible to local temperature variations.
- the control for the S purge is performed.
- S purge control start conditions are not limited to this.
- S purge control may be started every predetermined operating time of the engine 1, or downstream of the NOx storage catalyst 36.
- a NOx sensor may be provided on the side, and the control of the S purge may be started when the amount of NOx in the exhaust gas detected by the NOx sensor exceeds a predetermined amount.
- control termination condition for the S purge is not limited to the elapsed time after starting the HC supply by the rich spike as in the above embodiment.
- the NOx purification of the NOx storage catalyst 36 will be performed when the detection value after starting the S purge control falls below a predetermined value.
- the control for S purge may be terminated as the function has been restored, or the elapsed time from the start of HC supply by rich spike may be varied according to the operating state of engine 1. Oh ,.
- the exhaust aftertreatment device 28 is configured by a single casing having a force formed by dividing the exhaust aftertreatment device 28 into the upstream casing 30 and the downstream casing 34. A little.
- the present invention is applied to an exhaust gas purification device for a diesel engine.
- the engine type is not limited to this, and a NOx storage catalyst and the NOx storage catalyst. Any engine equipped with HC supply means for supplying HC to the engine can be applied.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Environmental & Geological Engineering (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Toxicology (AREA)
- Exhaust Gas After Treatment (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/997,691 US20100218486A1 (en) | 2005-08-04 | 2005-08-01 | Exhaust gas purification device |
DE112006002021T DE112006002021T5 (de) | 2005-08-04 | 2006-08-01 | Abgasreinigungsgerät |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP2005-226596 | 2005-08-04 | ||
JP2005226596A JP2007040222A (ja) | 2005-08-04 | 2005-08-04 | 排気浄化装置 |
Publications (1)
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WO2007015478A1 true WO2007015478A1 (ja) | 2007-02-08 |
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ID=37708759
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/JP2006/315193 WO2007015478A1 (ja) | 2005-08-04 | 2006-08-01 | 排気浄化装置 |
Country Status (5)
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US (1) | US20100218486A1 (ja) |
JP (1) | JP2007040222A (ja) |
CN (1) | CN101228341A (ja) |
DE (1) | DE112006002021T5 (ja) |
WO (1) | WO2007015478A1 (ja) |
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KR101028556B1 (ko) * | 2008-12-05 | 2011-04-11 | 기아자동차주식회사 | 배기 가스 정화 장치 |
KR20110023158A (ko) * | 2009-08-28 | 2011-03-08 | 현대자동차주식회사 | 배기 시스템 |
CN103080493A (zh) * | 2010-07-07 | 2013-05-01 | 丰田自动车株式会社 | 内燃机 |
WO2014162163A1 (en) * | 2013-04-03 | 2014-10-09 | Renault Trucks | Method and internal combustion engine arrangement for regenerating an exhaust after-treatment device |
CN112610316B (zh) * | 2020-12-10 | 2022-02-25 | 安徽江淮汽车集团股份有限公司 | 温度检测装置和方法 |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH11343836A (ja) * | 1998-06-03 | 1999-12-14 | Toyota Motor Corp | 内燃機関の排気浄化装置 |
JP2004068700A (ja) * | 2002-08-06 | 2004-03-04 | Toyota Motor Corp | 排気ガス浄化方法 |
JP2004176632A (ja) * | 2002-11-27 | 2004-06-24 | Toyota Motor Corp | 内燃機関の排気浄化装置 |
Family Cites Families (5)
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JP3835241B2 (ja) * | 2001-10-15 | 2006-10-18 | トヨタ自動車株式会社 | 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 |
JP2005048746A (ja) * | 2003-07-31 | 2005-02-24 | Nissan Motor Co Ltd | 内燃機関の燃焼制御装置 |
JP3876874B2 (ja) * | 2003-10-28 | 2007-02-07 | トヨタ自動車株式会社 | 触媒再生方法 |
JP4125255B2 (ja) * | 2004-03-11 | 2008-07-30 | トヨタ自動車株式会社 | 内燃機関の排気浄化装置 |
-
2005
- 2005-08-01 US US11/997,691 patent/US20100218486A1/en not_active Abandoned
- 2005-08-04 JP JP2005226596A patent/JP2007040222A/ja active Pending
-
2006
- 2006-08-01 DE DE112006002021T patent/DE112006002021T5/de not_active Withdrawn
- 2006-08-01 CN CNA2006800269134A patent/CN101228341A/zh active Pending
- 2006-08-01 WO PCT/JP2006/315193 patent/WO2007015478A1/ja active Application Filing
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH11343836A (ja) * | 1998-06-03 | 1999-12-14 | Toyota Motor Corp | 内燃機関の排気浄化装置 |
JP2004068700A (ja) * | 2002-08-06 | 2004-03-04 | Toyota Motor Corp | 排気ガス浄化方法 |
JP2004176632A (ja) * | 2002-11-27 | 2004-06-24 | Toyota Motor Corp | 内燃機関の排気浄化装置 |
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CN101228341A (zh) | 2008-07-23 |
JP2007040222A (ja) | 2007-02-15 |
DE112006002021T5 (de) | 2008-06-12 |
US20100218486A1 (en) | 2010-09-02 |
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