US20020134075A1 - Method for operation of a nox storage catalyst in internal combustion engines - Google Patents

Method for operation of a nox storage catalyst in internal combustion engines Download PDF

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Publication number
US20020134075A1
US20020134075A1 US09/914,468 US91446801A US2002134075A1 US 20020134075 A1 US20020134075 A1 US 20020134075A1 US 91446801 A US91446801 A US 91446801A US 2002134075 A1 US2002134075 A1 US 2002134075A1
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United States
Prior art keywords
exhaust gas
nox
catalytic converter
oxygen
exhaust
Prior art date
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Abandoned
Application number
US09/914,468
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English (en)
Inventor
Wilhelm Polach
Bernd Hupfeld
Thomas Wahl
Frank Brenner
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Robert Bosch GmbH
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Individual
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Filing date
Publication date
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Assigned to ROBERT BOSCH GMBH reassignment ROBERT BOSCH GMBH ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: BRENNER, FRANK, WAHL, THOMAS, HUPFELD, BERND, POLACH, WILHELM
Publication of US20020134075A1 publication Critical patent/US20020134075A1/en
Abandoned legal-status Critical Current

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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
    • 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
    • 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
    • F02D41/027—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
    • F01N2610/00—Adding substances to exhaust gases
    • F01N2610/03—Adding substances to exhaust gases the substance being hydrocarbons, e.g. engine fuel

Definitions

  • the invention relates to the operation of an NOx storage catalytic converter in internal combustion engines which are operated with a lean air/fuel mixture.
  • internal combustion engines are lean operated spark ignition engines or diesel engines.
  • NOx storage catalytic converters are used for the exhaust-gas after treatment in the combustion of lean air/fuel mixtures.
  • the NOx storage catalytic converters store the nitrogen oxide, which is emitted in lean engine operation, in a first operating phase whose length is in the order of magnitude of minutes.
  • a second shorter operating phase having a length in the range of seconds, an emptying of the storage takes place via the supply of exhaust gas with a reducing agent to the storage catalytic converter.
  • the storage capability of the NOx catalytic converter is dependent upon charge and reduces continuously. If the first phase takes too long, then unwanted nitrogen oxide emissions occur. A second phase which takes too long has increased HC emissions and CO emissions as a consequence.
  • the regeneration is preferably achieved by injecting fuel into the exhaust-gas system ahead of the catalytic converter.
  • the transition from lean to rich and the total regeneration process is especially critical because the varying flow conditions make the appropriate metering for generating a homogeneous distribution of the reducing agent in the exhaust gas ahead of the catalytic converter difficult. This transition phase appears not to be capable of being modeled with a reasonable complexity under the changing flow conditions in the exhaust gas.
  • the invention relates to the problem of controlling the change between the two phases.
  • An advantage of the invention lies in the significantly more unified conditions of the regeneration phase.
  • FIG. 1 shows the technical background in which the invention develops its effect
  • FIG. 2 shows time-dependent traces of various signals
  • FIG. 3 shows a modified structure for realizing the invention
  • FIG. 4 shows an embodiment in the form of a flowchart.
  • FIG. 1 shows an internal combustion engine 1 having an NOx storage catalytic converter 2 , exhaust-gas probes 3 and 4 , a control apparatus 5 , a fuel metering device 6 and various sensors ( 7 , 8 , 9 ) for load L and rpm n as well as other operating parameters of the engine as may be required such as temperature, throttle flap position, et cetera.
  • the control apparatus forms, inter alia, fuel metering signals with which the fuel metering means 6 is driven.
  • the fuel metering means 6 can be configured for a so-called intake manifold injection as well as for a gasoline direct injection into the combustion chambers la of the individual cylinders.
  • the variation of the mixture composition can take place via a change of the injection pulse widths with which the fuel metering means is driven.
  • the essence of the method of the invention relates, in this environment, primarily to the control apparatus 5 and the exhaust-gas probe 4 mounted rearward of the catalytic converter.
  • FIG. 2 presents in FIG. 2 a the change in the mixture composition “lambda” ahead of the catalytic converter (line 2 a ) in combination with the signal US of the rearward exhaust-gas probe 4 (line 2 b ) and the NOx concentration (line 2 c ) rearward of the catalytic converter.
  • the rearward exhaust-gas probe can, for example, be realized as an oxygen measuring sensor, a hydrocarbon sensor (HC sensor), as a carbon dioxide sensor (CO sensor) or as a nitrogen oxide sensor. What is shown is the signal of an oxygen sensor which supplies a high signal level when there is an oxygen deficiency and a low signal level when there is an oxygen excess.
  • the low signal level of the rearward probe (line 2 b ) indicates that an air or oxygen excess is present also rearward of the catalytic converter.
  • the mixture composition is reversed from lambda greater than one to lambda less than one, that is, oxygen deficiency.
  • the rearward sensor 4 reacts to the oxygen deficiency with an increase of its signal from a low level to the high level.
  • the illustrated change of the mixture composition leads to the situation that the engine emits hydrocarbons and carbon monoxide as reducing agents.
  • the reducing agent can be supplied from a supply tank 11 via a valve 12 to the exhaust gas forward of the catalytic converter.
  • the valve 12 is driven by the control apparatus 5 .
  • the engine can then be operated continuously with a lean mixture.
  • FIG. 3 A corresponding modification of the structure of FIG. 1 is shown in FIG. 3.
  • the regeneration phase is not modeled via computations and therefore is held variable.
  • a predetermined constant mass of fuel is introduced into the exhaust-gas system ahead of the catalytic converter in each case for regeneration.
  • the storing phase is then adapted in its duration to the regeneration phase. Defective adaptations are determined by an exhaust-gas probe mounted rearward of the catalytic converter and are reduced by influencing the length of the storing phase. For this purpose, the storing phase is shortened when an exhaust-gas probe signals no adequate change of the concentration of an exhaust-gas component toward the end of the regeneration phase. If such a change occurs, however, too early, then the storing phase is lengthened.
  • FIG. 4 An embodiment of the method of the invention is shown in FIG. 4.
  • Step 1 represents an engine operation with a lean mixture.
  • the NOx which is emitted by the engine in this operating phase, it taken up by the storage catalytic converter.
  • the degree of charge of the storage catalytic converter is computed in step 2 from operating parameters of the engine such as known, for example, from DE 197 39 848.
  • control apparatus If the degree of the charge reaches a threshold value SW—NOx, the control apparatus triggers a regeneration of the storage catalytic converter. This is shown in steps 3 and 4 .
  • the predetermined mass of reducing agent can be metered from the tank 11 into the exhaust gas forward of the storage catalytic converter via the controllable valve 12 .
  • the predetermined mass of reducing agent is generated in the exhaust gas by a rich engine operation. For example, all fuel metering signals, which are specific for the normal engine operation with lean mixture, can be increased in a predetermined manner until the sum of the increases of the fuel metering signals corresponds to the desired fuel mass predetermined for the regeneration.
  • the signal does not reach the threshold, this means that no oxygen deficiency has arisen rearward of the catalytic converter at the end of the regeneration.
  • the reducing agent quantity has then not been adequate to completely regenerate the NOx storage catalytic converter.
  • it is not the reduction agent quantity which is increased, but the storing phase is shortened.
  • the illustrated example achieves the shortening via a reduction of the threshold value SW—NOx in step 6 . If, in contrast, the reaction of the rearward probe is too pronounced (which, for example, can be determined in step 5 by the threshold value being exceeded), a lengthening of the storing phase takes place in step 7 via an increase of the threshold value SW—NOx.
US09/914,468 1999-12-29 2000-12-29 Method for operation of a nox storage catalyst in internal combustion engines Abandoned US20020134075A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19963624A DE19963624A1 (de) 1999-12-29 1999-12-29 Verfahren zum Betrieb eines NOx-Speicherkatalysators bei Brennkraftmaschinen
DE19963624.9 1999-12-29

Publications (1)

Publication Number Publication Date
US20020134075A1 true US20020134075A1 (en) 2002-09-26

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US09/914,468 Abandoned US20020134075A1 (en) 1999-12-29 2000-12-29 Method for operation of a nox storage catalyst in internal combustion engines

Country Status (7)

Country Link
US (1) US20020134075A1 (de)
EP (1) EP1163431B1 (de)
JP (1) JP2003519317A (de)
KR (1) KR20010102422A (de)
CN (1) CN1342244A (de)
DE (2) DE19963624A1 (de)
WO (1) WO2001049985A1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080173009A1 (en) * 2006-12-22 2008-07-24 Kocher Lyle E System for controlling regeneration of an adsorber

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1687336B (zh) * 2005-04-06 2010-10-13 上海纳克润滑技术有限公司 一种高温链条油复合添加剂及其制备方法
DE102016219301A1 (de) * 2016-10-05 2018-04-05 Audi Ag Verfahren und Vorrichtung zur Abgasreinigung

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3228006B2 (ja) * 1994-06-30 2001-11-12 トヨタ自動車株式会社 内燃機関の排気浄化要素劣化検出装置
DE19739848A1 (de) * 1997-09-11 1999-03-18 Bosch Gmbh Robert Brennkraftmaschine insbesondere für ein Kraftfahrzeug
DE19755600C2 (de) * 1997-12-15 2002-01-17 Bosch Gmbh Robert Betrieb eines Verbrennungsmotors in Verbindungmit einem NOx-Speicherkatalysator
DE19830829C1 (de) * 1998-07-09 1999-04-08 Siemens Ag Verfahren zur Regeneration eines NOx-Speicherkatalysators

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080173009A1 (en) * 2006-12-22 2008-07-24 Kocher Lyle E System for controlling regeneration of an adsorber
US8474243B2 (en) 2006-12-22 2013-07-02 Cummins, Inc. System for controlling regeneration of an adsorber

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Publication number Publication date
WO2001049985A1 (de) 2001-07-12
EP1163431B1 (de) 2003-11-26
CN1342244A (zh) 2002-03-27
JP2003519317A (ja) 2003-06-17
DE19963624A1 (de) 2001-07-12
KR20010102422A (ko) 2001-11-15
EP1163431A1 (de) 2001-12-19
DE50004565D1 (de) 2004-01-08

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Owner name: ROBERT BOSCH GMBH, GERMANY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:POLACH, WILHELM;HUPFELD, BERND;WAHL, THOMAS;AND OTHERS;REEL/FRAME:012319/0593;SIGNING DATES FROM 20010802 TO 20010904

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION