EP2013455A1 - Épurateur de gaz d'échappement pour moteur à combustion interne - Google Patents

Épurateur de gaz d'échappement pour moteur à combustion interne

Info

Publication number
EP2013455A1
EP2013455A1 EP07742870A EP07742870A EP2013455A1 EP 2013455 A1 EP2013455 A1 EP 2013455A1 EP 07742870 A EP07742870 A EP 07742870A EP 07742870 A EP07742870 A EP 07742870A EP 2013455 A1 EP2013455 A1 EP 2013455A1
Authority
EP
European Patent Office
Prior art keywords
fuel ratio
exhaust gas
nox
air
nox absorbent
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP07742870A
Other languages
German (de)
English (en)
Inventor
Nobumoto Ohashi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toyota Motor Corp
Original Assignee
Toyota Motor Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toyota Motor Corp filed Critical Toyota Motor Corp
Publication of EP2013455A1 publication Critical patent/EP2013455A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • F02D41/0275—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 NOx trap or adsorbent
    • 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
    • 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
    • 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
    • F02D41/024—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to increase temperature of the exhaust gas treating apparatus
    • 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
    • F01N2250/00—Combinations of different methods of purification
    • F01N2250/14—Combinations of different methods of purification absorption or adsorption, and filtering
    • 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
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/08—Exhaust gas treatment apparatus parameters
    • F02D2200/0802—Temperature of the exhaust gas treatment apparatus
    • 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 gas purification device for an internal combustion engine.
  • a NOx absorbent is arranged in the exhaust passage of the engine in which an NOx absorbent absorbs NOx contained in the exhaust gas therein when the air-fuel ratio of the exhaust gas is lean and releases absorbed NOx therefrom when the air-fuel ratio of the exhaust gas is switched to rich, wherein a fuel supply valve is arranged in the exhaust passage upstream of the NOx absorbent, and wherein fuel is supplied from the fuel supply valve to the NOx absorbent to make the air-fuel ratio of exhaust gas flowing through the NOx absorbent temporarily rich, when the NOx must be released from the NOx absorbent (see Japanese Unexamined Patent Publication No. 11-62666, for example) .
  • NOx generated when combustion is carried out under a lean air-fuel ratio is absorbed in the NOx absorbent.
  • the air-fuel ratio is temporarily made rich to release NOx from the NOx absorbent and reduce the NOx.
  • the temperature of the NOx absorbent is lowered since the temperature of exhaust gas inflowing through the NOx absorbent at this time is low.
  • the release rate of NOx from the NOx absorbent is low. Therefore, if the air-fuel ratio of exhaust gas is simply switched to rich, it may be impossible to obtain an adequate release of NOx from the NOx absorbent.
  • an object of the present invention to provide an exhaust gas purification device for an internal combustion engine, which is capable of obtaining an adequate release of NOx from an NOx absorbent even when the temperature of the NOx absorbent is low.
  • an exhaust gas purification device for an internal combustion engine having an exhaust passage, combustion being carried out under a basic lean air-fuel ratio, comprising: a NOx absorbent arranged in the exhaust passage, the NOx absorbent absorbing NOx contained in exhaust gas therein when the air-fuel ratio of exhaust gas is lean and releasing absorbed NOx therefrom when the air-fuel ratio of exhaust gas is switched to rich; and control means for controlling the air-fuel ratio of exhaust gas flowing through the NOx absorbent, wherein, when NOx must be released from the NOx absorbent, the air-fuel ratio of exhaust gas flowing through the NOx absorbent is first switched from the basic lean air-fuel ratio to and maintained at a lean air-fuel ratio with a lower leanness for a predetermined lean time, and is then switched to a rich air-fuel ratio.
  • Fig. 1 is an overall view of an internal combustion engine of a compression ignition type
  • Fig. 2 is a sectional side view of a NOx storing catalyst
  • Figs. 3A and 3B are sectional views of a surface part of a catalyst carrier
  • Figs. 4A and 4B are views of the structure of a particulate filter
  • Fig. 5 is a time chart explaining a NOx release control
  • Fig. 6 is a map illustrating the amount of NOx adsorbed per unit time dNOx
  • Figs. 7A and 7B are time charts illustrating variations of the air-fuel ratio of flowing exhaust gas AFEG;
  • Fig. 8 is a map illustrating a predetermined temperature TcS
  • Figs. 9A to 9D are maps illustrating lean time tL, respectively.
  • Fig. 10 is a flowchart for executing the NOx release control .
  • Fig. 1 illustrates a case where the present invention is applied to an internal combustion engine with a compression type ignition.
  • the present invention may also be applied to an internal combustion engine with a spark type ignition.
  • numeral 1 indicates an engine body, 2 a combustion chamber of each cylinder, 3 an electrically-controlled fuel injector for injecting fuel into each combustion chamber 2, 4 an intake manifold, and 5 an exhaust manifold.
  • the intake manifold 4 is connected through an intake duct 6 to an outlet of a compressor 7a of a turbocharger 7.
  • the inlet of the compressor 7a is connected via an air flow meter 8 to an air cleaner 9.
  • An electrically-controlled throttle valve 10 is arranged in the intake duct 6.
  • a cooling device 11 is arranged around the intake duct ⁇ for cooling intake air flowing through the intake duct 6.
  • engine cooling water is guided into the cooling device 11 and cools intake air.
  • the exhaust manifold 5 is connected to an inlet of an exhaust turbine 7b of the exhaust turbocharger 7, while the outlet of the exhaust turbine 7b is connected to an exhaust aftertreatment system 20.
  • the exhaust manifold 5 and the intake manifold 4 are interconnected through an exhaust gas recirculation
  • EGR passage 12 (hereinafter referred to as an "EGR") passage 12.
  • the EGR passage 12 is provided with an electrically-controlled EGR control valve 13.
  • a cooling device 14 is arranged around the EGR passage 12 for cooling EGR gas flowing through the EGR passage 12.
  • engine cooling water is guided into the cooling device 14 and cools the EGR gas.
  • Each fuel injector 3 is connected through a fuel feed tube 15 to a common rail 16.
  • This common rail 16 is supplied with fuel from an electrically-controlled type variable discharge fuel pump 20. Fuel supplied into the common rail 16 is supplied through each fuel feed tube 15 to the fuel injector 3.
  • the exhaust aftertreatment system 20 comprises an exhaust pipe 21 connected to an outlet of the exhaust turbine 7b, a catalytic converter 22 connected to the exhaust pipe 21, and an exhaust pipe 23 connected to the catalytic converter 22.
  • a NOx storing catalyst 24 and a particulate filter 25 are arranged in the catalytic converter 22 in order, starting from the upstream side.
  • a temperature sensor 26 for detecting the temperature of exhaust gas discharged from the catalytic converter 22 and an air-fuel ratio sensor 27 for detecting the air-fuel ratio of exhaust gas discharged from the catalytic converter 22 are arranged in the exhaust pipe 23.
  • the temperature of exhaust gas discharged from the catalytic converter 22 represents the temperature of the NOx storing catalyst 24 and the particulate filter 25.
  • the exhaust manifold 5 is provided with a fuel supply valve 28.
  • the fuel supply valve 28 is supplied with fuel from the common rail 16, the fuel is fed from the fuel supply valve 28 to the exhaust manifold 5.
  • fuel is comprised of light oil.
  • the fuel supply valve 28 may be arranged in the exhaust pipe 21, alternatively.
  • An electronic control unit 30 is comprised of a digital computer provided with read only memory (ROM) 32, TM" O ⁇
  • RAM random access memory
  • CPU microprocessor
  • input port 35 an output port 36, all connected to each other by a bidirectional bus 31.
  • the output signals of the air flow meter 8, the temperature sensor 26 and the air-fuel ratio sensor 27 are input through corresponding AD converters 37 to the input port 35.
  • a load sensor 40 generating output voltage proportional to the amount of the depression L of an accelerator pedal 39.
  • Outputted voltage of the load sensor 40 is input through a corresponding AD converter 37 to the input port 35.
  • crank angle sensor 41 connected to the input port 35 is a crank angle sensor 41 generating an output pulse each time the crankshaft turns, for example, by 15 degrees.
  • the CPU 34 calculates engine speed N based on the output pulse from the crank angle sensor 41.
  • the output port 36 is connected through corresponding drive circuits 38 to the fuel injectors 3, driver for the throttle valve 10, EGR control valve 13, fuel pump 20, and fuel supply valve 28.
  • Fig. 2 shows the structure of the NOx storing catalyst 24.
  • the NOx storing catalyst 24 is formed of a honeycomb structure and is provided with a plurality of exhaust gas passages 61 separated from each other by partitions 60.
  • the opposite surfaces of the partitions 60 carry a catalyst carrier comprised of, for example, alumina.
  • Figs. 3A and 3B schematically show the cross-section of the surface part of this catalyst carrier 65.
  • the catalyst carrier 65 carries a precious metal catalyst 66 diffused on its surface.
  • the catalyst carrier 65 is formed with a layer of a NOx absorbent 67 on its surface.
  • platinum Pt is used as the precious metal catalyst 66.
  • the ingredient for forming the NOx absorbent 67 for example, at least one element selected - -
  • the ratio of air and fuel (hydrocarbons) supplied to the engine intake passage, combustion chambers 2, and exhaust passage upstream of the NOx storing catalyst 24 is referred to as an air-fuel ratio of the exhaust gas.
  • the NOx absorbent 67 performs NOx absorption and release action of absorbing the NOx when the air-fuel ratio of the exhaust gas is lean and releasing the absorbed NOx when the oxygen concentration in the exhaust gas falls.
  • the NOx absorbent 67 when the air- fuel ratio of exhaust gas is lean, that is, when the oxygen concentration in exhaust gas is high, the NO contained in the exhaust gas is oxidized on the platinum Pt 66 such as shown in Fig. 3A to become NO 2 , and is then absorbed in the NOx absorbent 67 and diffused in the NOx absorbent 67 in the form of nitric acid ions N ⁇ 3 ⁇ while bonding with the barium carbonate BaCO3. In this way, NOx is absorbed in the NOx absorbent 67. If the oxygen concentration in the exhaust gas is high, NO 2 is produced on the surface of the platinum Pt 66. If the NOx absorbing capability of the NOx absorbent 67 is not saturated, the NO 2 is absorbed in the NOx absorbent 67 and nitric acid ions NO 3 " are produced.
  • fuel is supplied from the fuel supply valve 28 so as to temporarily make the air-fuel ratio of the exhaust gas rich, and thereby release NOx from the NOx absorbent 67.
  • Figs. 4A and 4B show the structure of the particulate filter 25.
  • Fig. 4A is a front view of the particulate filter 25
  • Fig. 4B is a side sectional view of the particulate filter 25.
  • the particulate filter 25 forms a honeycomb structure and is provided with a plurality of exhaust passages 70 and 71 extending parallel with each other. These exhaust passages are comprised of exhaust gas inflow passages 70 with downstream ends sealed by plugs 72 and exhaust gas outflow passages 71 with upstream ends sealed by plugs 73. Note that the hatched portions in Fig. 4A show plugs 73.
  • the exhaust gas inflow passages 70 and exhaust gas outflow passages 71 are arranged alternately through thin wall partitions 74.
  • the exhaust gas inflow passages 70 and exhaust gas outflow passages 71 are arranged so that each exhaust gas inflow passage 70 is surrounded by four exhaust gas outflow passages 71, and each exhaust gas outflow passage 71 is surrounded by four exhaust gas inflow passages 70.
  • the particulate filter 25 is formed from a porous material such as cordierite. Therefore, exhaust gas flowing into the exhaust gas inflow passages 70 flows out into the adjoining exhaust gas outflow passages 71 through the surrounding partitions 74 as shown by the arrows in Fig. 4B.
  • the peripheral walls of the exhaust gas inflow passages 70 and exhaust gas outflow passages 71 that is, the opposite surfaces of the partitions 74 and the inside walls of the micropores of the partitions 74 also carry a catalyst carrier comprised of, for example, alumina. As shown in Figs. 3A and 3B, the catalyst carrier 65 carries a precious metal catalyst 66 diffused on its surface.
  • the catalyst carrier 65 is formed with a layer of the NOx absorbent 67 on its surface. Therefore, combustion under a lean air-fuel ratio is carried out, NOx contained in the exhaust gas is also absorbed in the NOx absorbent 67 carried on the particulate filter 25. The thus absorbed NOx is released and reduced by supplying fuel from the fuel supply valve 28.
  • the particulate matter contained in the exhaust gas is trapped on the particulate filter 25 and successively oxidized.
  • the particulate matter trapped becomes greater than the amount of the particulate matter oxidized, the particulate matter will gradually be deposited on the particulate filter 25.
  • engine output may be decreased. Therefore, it is necessary to remove the deposited particulate matter when the amount of particulate matter deposited increases. In this case, if raising the temperature of the particulate filter 25 under an excess of air to about 600 0 C, the deposited particulate matter is oxidized and removed.
  • a particulate filter that does not carry NOx absorbent 67 may be used as a particulate filter 25.
  • the amount of NOx dNOx absorbed in the NOx absorbent 67 per unit of time is stored in ROM 32 in advance in the form of a map as shown in Fig. 6 as a function of the required torque TQ and engine speed N.
  • the cumulative NOx amount ⁇ NOx is calculated by a cumulation of the NOx amount of dNOx.
  • the temperature Tc of the NOx absorbent 67 is first detected, and the air-fuel ratio of the exhaust gas flowing to the NOx absorbent 67 is switched to a rich air-fuel ratio or is changed depending on the absorbent temperature Tc. This will be explained with reference to Figs. 7A and 7B.
  • Fig. 7A shows a case where the temperature Tc of the NOx absorbent 67 is lower than a predetermined temperature TcS.
  • fuel supply from the fuel supply valve 28 is not carried out until the timing indicated by X, that is, until the cumulative NOx amount ⁇ NOx exceeds the allowable amount MAX and NOx must be released from the NOx absorbent 67 (see Fig. 5) .
  • the air-fuel ratio AFEG of exhaust gas flowing through the NOx absorbent 67 is maintained at a lean air- fuel ratio.
  • the lean air-fuel ratio at this time is a basic lean air-fuel ratio AFLB
  • the basic air-fuel ratio AFLB conforms to the air-fuel ratio in the combustion chambers 2, in the engine shown in Fig. 1.
  • fuel from the fuel supply valve 28 is switched to start the air-fuel ratio of the inflowing exhaust gas AFEG from the basic lean air-fuel ratio AFLB to a lean air-fuel ratio with a lower leanness AFLL.
  • the air-fuel ratio of the inflowing exhaust gas AFEG is a basic lean air-fuel ratio AFLB.
  • the increased amount of unburned HC and CO will be oxidized in the NOx absorbent 67 under the presence of excess oxygen, and thus the temperature Tc of the NOx absorbent 67 increases rapidly. Therefore, the air-fuel ratio of inflowing exhaust gas AFEG is switched to the rich air-fuel ratio AFR after the temperature Tc of the NOx absorbent 67 is high, and an adequate NOx release from the NOx absorbent 67 is accordingly obtained.
  • the air-fuel ratio of the inflowing exhaust gas AFEG is returned from the rich air-fuel ratio AFR back to the basic lean air-fuel ratio AFLB, and is maintained at the basic lean air-fuel ratio AFLB until the NOx must be released from the NOx absorbent 67 again as shown in Fig. 5.
  • fuel from the fuel supply valve 28 is stopped when the air-fuel ratio of the inflowing exhaust gas AFEG is returned back to the basic lean air-fuel ratio AFLB until the cumulative NOx amount ⁇ NOx exceeds the allowable amount MAX again.
  • the predetermined temperature TcS is a temperature required for a good release of NOx from the NOx absorbent 67.
  • the temperature necessary for a good release of NOx from the NOx absorbent 67 will vary depending on the degree of deterioration of the NOx absorbent 67. Therefore, in the embodiment according to the present invention, the degree of the deterioration DET of the NOx absorbent 67 is first detected, and the predetermined temperature TcS is then determined depending on the degree of deterioration DET of the NOx absorbent 67. Specifically, the predetermined temperature TcS is set higher as the degree of deterioration DET becomes higher, as shown in Fig. 8.
  • the predetermined temperature TcS is stored in ROM 32 in advance, in the form of a map as shown in Fig. 8. Note that there are many procedures for obtaining the degree of deterioration DET of the NOx absorbent 67. For example, the degree of deterioration DET of the NOx absorbent 67 may be judged to be higher as the increment of the temperature Tc of the NOx absorbent 67 obtained when fuel is supplied from the fuel supply valve 28 to the NOx absorbent 67 is smaller.
  • TcY indicated in Fig. 7A is the temperature Tc of the NOx absorbent 67 when the lean time tL has elapsed from when the air-fuel ratio of inflowing exhaust gas AFEG is switched to the lean air-fuel ratio with a lower leanness AFLL. If the temperature TcY conforms approximately to the predetermined temperature TcS mentioned above, an adequate NOx release will be obtained while the amount of fuel from the fuel supply valve 28 is kept low.
  • the lean time tL is the amount of time required to increase the temperature Tc of the NOx absorbent 67 to approximately the predetermined temperature TcS when the air-fuel ratio of the inflowing exhaust gas AFEG is maintained at the lean air-fuel ratio with a lower leanness AFLL.
  • the lean time tL becomes longer as the temperature Tc of the NOx absorbent 67 becomes lower as shown in Fig. 9A, as the amount of intake air Ga becomes larger as shown in Fig. 9B, and as the degree of deterioration DET of the NOx absorbent 67 becomes higher as shown in Fig. 9C.
  • the lean time tL is stored in ROM 32 in advance, in the form of a map shown in Fig. 9D, as a function of the temperature Tc and the degree of deterioration DET of the NOx absorbent 67 and the amount of intake air Ga.
  • the amount of intake air Ga represents the amount of exhaust gas flowing through the NOx absorbent 67.
  • Fig. 10 shows a routine of the NOx release control. Referring to Fig. 10, the routine proceeds to step 100 where the amount of NOx ⁇ NOx absorbed in the NOx absorbent 67 is calculated. Specifically, in the embodiment according to the present invention, the amount of NOx dNOx adsorbed in the NOx absorbent 67 per unit time is calculated using the map shown in Fig. 6, and is then added to the absorbed NOx amount ⁇ NOx.
  • step 101 it is determined whether the absorbed NOx amount ⁇ NOx exceeds the allowable amount MAX.
  • the processing cycle is ended.
  • the routine proceeds to step 102 where the predetermined temperature TcS is calculated using the map shown in Fig. 8.
  • step 103 it is determined whether the temperature Tc of the NOx absorbent 67 is lower than the predetermined temperature TcS.
  • step 104 the lean time tL is calculated using the map shown in Fig. 9D.
  • step 105 the fuel supply valve 28 supplies fuel to maintain the air-fuel ratio of inflowing exhaust gas AFEG at the lean air-fuel ratio with a lower leanness AFLL for the lean time tL.
  • step 106 the routine jumps from step 103 to step 106.
  • step 106 the fuel supply valve 28 supplies fuel to maintain the air-fuel ratio of the inflowing exhaust gas AFEG at the rich air-fuel ratio AFR for the rich time tR.
  • step 107 the absorbed NOx amount ⁇ NOx is returned to zero.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)
  • Exhaust Gas Treatment By Means Of Catalyst (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Abstract

Selon l'invention, un absorbant de Nox est disposé dans une sortie d'échappement d'un moteur à combustion interne, et une soupape d'alimentation en carburant (28) est disposée dans la sortie d'échappement en amont de l'absorbant de Nox. Si la température de l'absorbant de Nox est inférieure à une température préétablie lorsque le Nox doit être libéré de l'absorbant de Nox, le rapport du mélange air-carburant du gaz d'échappement s'écoulant à travers l'absorbant de Nox est d'abord basculé et maintenu d'un rapport du mélange air-carburant pauvre basique à un rapport du mélange air-carburant pauvre en état de basse teneur inférieure, pendant une période de basse teneur préétablie, après quoi il est basculé à un rapport du mélange air-carburant riche. Si la température de l'absorbant de Nox est supérieure à la température préétablie lorsque le Nox doit être libéré de l'absorbant de Nox, le rapport du mélange air-carburant du gaz d'échappement s'écoulant à travers l'absorbant de Nox est basculé au rapport du mélange air-carburant riche sans être basculé au rapport du mélange air-carburant pauvre en état de basse teneur inférieure.
EP07742870A 2006-04-27 2007-04-26 Épurateur de gaz d'échappement pour moteur à combustion interne Withdrawn EP2013455A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2006123785A JP2007297918A (ja) 2006-04-27 2006-04-27 内燃機関の排気浄化装置
PCT/JP2007/059435 WO2007126140A1 (fr) 2006-04-27 2007-04-26 Épurateur de gaz d'échappement pour moteur à combustion interne

Publications (1)

Publication Number Publication Date
EP2013455A1 true EP2013455A1 (fr) 2009-01-14

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP07742870A Withdrawn EP2013455A1 (fr) 2006-04-27 2007-04-26 Épurateur de gaz d'échappement pour moteur à combustion interne

Country Status (5)

Country Link
US (1) US20090049825A1 (fr)
EP (1) EP2013455A1 (fr)
JP (1) JP2007297918A (fr)
CN (1) CN101427010A (fr)
WO (1) WO2007126140A1 (fr)

Families Citing this family (25)

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US7040094B2 (en) * 2002-09-20 2006-05-09 The Regents Of The University Of California Staged combustion with piston engine and turbine engine supercharger
JP5495293B2 (ja) 2009-07-06 2014-05-21 株式会社日立産機システム 圧縮機
BRPI1012615B1 (pt) 2010-03-15 2020-08-11 Toyota Jidosha Kabushiki Kaisha Sistema de purificação de exaustão de motor de combustão interna
ES2508365T3 (es) 2010-03-15 2014-10-16 Toyota Jidosha Kabushiki Kaisha Método de operación de un sistema de purificación de gases de escape de un motor de combustión interna
WO2011125198A1 (fr) 2010-04-01 2011-10-13 トヨタ自動車株式会社 Dispositif de purification de gaz d'échappement pour moteur à combustion interne
JP5196024B2 (ja) 2010-07-28 2013-05-15 トヨタ自動車株式会社 内燃機関の排気浄化装置
WO2012029187A1 (fr) 2010-08-30 2012-03-08 トヨタ自動車株式会社 Dispositif de purification des gaz d'échappement pour un moteur à combustion interne
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JP5168412B2 (ja) 2010-09-02 2013-03-21 トヨタ自動車株式会社 内燃機関の排気浄化装置
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