WO2010096782A2 - Compensation de la dégradation d'un catalyseur post-traitement - Google Patents

Compensation de la dégradation d'un catalyseur post-traitement Download PDF

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Publication number
WO2010096782A2
WO2010096782A2 PCT/US2010/024954 US2010024954W WO2010096782A2 WO 2010096782 A2 WO2010096782 A2 WO 2010096782A2 US 2010024954 W US2010024954 W US 2010024954W WO 2010096782 A2 WO2010096782 A2 WO 2010096782A2
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WIPO (PCT)
Prior art keywords
value
reductant
catalyst
adjusted
degradation
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PCT/US2010/024954
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English (en)
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WO2010096782A3 (fr
Inventor
Jim C. Clerc
Timothy M. White
Melissa A. Zaczek
Baohua Qi
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Cummins Emission Solutions
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Publication of WO2010096782A2 publication Critical patent/WO2010096782A2/fr
Publication of WO2010096782A3 publication Critical patent/WO2010096782A3/fr
Priority to US13/215,162 priority Critical patent/US20120067028A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F01N3/208—Control of selective catalytic reduction [SCR], e.g. dosing of reducing agent
    • 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
    • F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
    • F01N11/002—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity the diagnostic devices measuring or estimating temperature or pressure in, or downstream of the exhaust 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
    • F01N2550/00—Monitoring or diagnosing the deterioration of exhaust systems
    • F01N2550/02—Catalytic activity of catalytic converters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/06—Parameters used for exhaust control or diagnosing
    • F01N2900/14—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust gas
    • F01N2900/1402—Exhaust gas composition
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/06—Parameters used for exhaust control or diagnosing
    • F01N2900/14—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust gas
    • F01N2900/1411—Exhaust gas flow rate, e.g. mass flow rate or volumetric flow rate
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/06—Parameters used for exhaust control or diagnosing
    • F01N2900/16—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust apparatus, e.g. particulate filter or catalyst
    • F01N2900/1602—Temperature of exhaust gas 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
    • F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/06—Parameters used for exhaust control or diagnosing
    • F01N2900/16—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust apparatus, e.g. particulate filter or catalyst
    • F01N2900/1616—NH3-slip from catalyst
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/06—Parameters used for exhaust control or diagnosing
    • F01N2900/16—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust apparatus, e.g. particulate filter or catalyst
    • F01N2900/1621—Catalyst conversion efficiency
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/06—Parameters used for exhaust control or diagnosing
    • F01N2900/16—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust apparatus, e.g. particulate filter or catalyst
    • F01N2900/1622—Catalyst reducing agent absorption capacity or consumption amount
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

Definitions

  • the technical field generally relates to internal combustion engine aftertreatment systems.
  • a variety of aftertreatment systems include one or more catalytic components that experience degradation and/or reduced efficiency over time. Efficiency reductions can affect the conversion capability of the catalyst, and can also affect the storage capacity of the catalyst as an adsorption device. Degradation of a catalyst introduces challenges into the system to continue to meet emissions targets and in some cases to continue to meet target levels of undesirable constituents in the exhaust. In some systems, a system response to continue to meet emissions may increase the amount of undesirable constituents in the exhaust. In some systems, the appropriate system response to a catalyst degradation may be variable depending upon the current operating conditions. Therefore, further improvements in this area of technology are desirable.
  • One embodiment is a unique method for compensating for catalyst degradation in an aftertreatment system. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings.
  • Fig. 1 is a schematic diagram of a system for compensating for catalyst degradation.
  • Fig. 2 is a schematic diagram of an apparatus for compensating for catalyst degradation.
  • Fig. 3 is an illustration of a space-velocity temperature map for a non-degraded catalyst.
  • Fig. 4 is an illustration of a space- velocity temperature map for a degraded catalyst.
  • Fig. 5 is an illustration of catalyst degradation values as a function of temperature.
  • Fig. 6 is an alternate illustration of catalyst degradation values as a function of temperature.
  • Fig. 7 is a schematic flow diagram of a procedure for compensating for catalyst degradation.
  • Fig. 8 is a schematic flow diagram of an alternate procedure for compensating for catalyst degradation.
  • Fig. 1 is a schematic diagram of a system 100 for compensating for catalyst degradation.
  • the system 100 includes an aftertreatment catalyst 102 disposed in an exhaust stream 104 of an internal combustion engine 106.
  • the aftertreatment catalyst 102 may be any type of catalyst that works in conjunction with a reductant 108, and includes at least a selective catalytic reduction (SCR) catalyst or a NO x adsorption catalyst.
  • the system 100 may further include a particulate filter (not shown) upstream or downstream of the aftertreatment catalyst 102, and a clean-up catalyst 122 downstream of the aftertreatment catalyst 102.
  • the clean-up catalyst 122 may be an ammonia oxidation catalyst, a catalyst to oxidize unburned hydrocarbons, or to catalyze any other undesirable constituents of the exhaust stream 104.
  • the system 100 includes the reductant 108 that reacts with an amount of NO x in the exhaust stream 104 in the presence of the aftertreatment catalyst 102.
  • the reductant 108 includes any product known to reduce NO x including at least ammonia, urea, and/or hydrocarbons.
  • the reductant 108 may be injected at other locations in the system 100, including addition of hydrocarbons by post-injection of fuel in the engine 106.
  • the system 100 further includes an injector 110 that injects the reductant 108 into the exhaust stream 104 at a position upstream of the aftertreatment catalyst 102.
  • the injector 110 may be located at any position in the system 100 upstream of the aftertreatment catalyst 102, including at least a position upstream of a turbocharger 112 and a position within a cylinder of the engine 106.
  • the system 100 further includes a controller 120 structured to perform certain operations to compensate for catalyst degradation.
  • the controller 120 forms a portion of a processing subsystem including one or more computing devices having memory, processing, and communication hardware.
  • the controller 120 may be a single device or a distributed device, and the functions of the controller 120 may be performed by hardware or software.
  • the controller 120 includes one or more modules structured to functionally execute the operations of the controller.
  • the description herein including modules emphasizes the structural independence of the aspects of the controller 120, and illustrates one grouping of operations and responsibilities of the controller 120. Other groupings that execute similar overall operations are understood within the scope of the present application. Modules may be implemented in hardware and/or software on computer readable medium, and modules may be distributed across various hardware or software components. More specific descriptions of certain embodiments of controller 120 operations are included in the section referencing FIG. 2.
  • the controller includes a degradation module, an injection amount module, a degradation compensation module, and/or an injection control module.
  • the degradation module interprets a catalyst degradation value corresponding to the aftertreatment catalyst 102
  • the injection amount module interprets a nominal reductant value comprising a nominal reductant to NO x ratio
  • the degradation compensation module determines an adjusted reductant value in response to the catalyst degradation value and the nominal reductant value
  • the controller 120 includes an injection control module that provides an injection rate signal based on the adjusted reductant value.
  • the injector 110 injects the reductant 108 into the exhaust stream 104 at a position upstream of the aftertreatment catalyst 102 in response to the injection rate signal.
  • Fig. 2 is a schematic diagram of an apparatus 200 for compensating for catalyst degradation.
  • the apparatus 200 may be a portion of a processing subsystem including a controller 120.
  • the controller 120 includes a degradation module 202, an injection amount module 204, and a degradation compensation module 206.
  • the degradation module 202 interprets a catalyst degradation value 210 corresponding to the aftertreatment catalyst 102.
  • Interpreting the catalyst degradation value 210 includes reading the catalyst degradation value 210 from a memory location, from a user input, over a datalink, and/or determining the catalyst degradation value 210 based on other parameters in the system 100.
  • the catalyst degradation value 210 includes a NO x conversion efficiency value 218 and/or a reductant storage value 220.
  • the catalyst degradation value 210 may include a description of a NOx conversion efficiency at a standard set of conditions based on the current level of catalyst degradation, and/or may include a description of a reductant storage amount (e.g. maximum storage value).
  • the reductant storage amount includes a storage description for the reductant 108 (e.g. ammonia) as the reductant 108 is stored on the aftertreatment catalyst 102, and may further include a description of adsorption and desorption dynamics of the reductant 108.
  • the reductant 108 may be urea
  • the catalyst degradation value 210 may include a reductant storage value 220 that describes an amount of ammonia that can be stored on the aftertreatment catalyst 102 at a standard set of conditions.
  • the catalyst degradation value 210 may be a function of a temperature of the aftertreatment catalyst 102 and/or a function of a space velocity of the exhaust stream 104 in the aftertreatment catalyst 102.
  • the catalyst degradation value 210 may include a description of a maximum amount of ammonia storage on the aftertreatment catalyst 102 across a range of operating temperatures.
  • the catalyst degradation value 210 may include a description of aNO x conversion efficiency (i.e. moles OfNO x converted for each mole of the limiting reactant available - either NO x or reductant) across a range of operating temperatures.
  • the catalyst degradation value 210 may include a description of a NO x conversion efficiency across a range of space velocity values.
  • the catalyst degradation value 210 may include a two-dimensional description of a NO x conversion efficiency across a range of space velocity values and a range of temperatures.
  • the catalyst degradation value 210 includes a description of a reductant storage amount based upon an amount of reductant present in the exhaust stream 104 — as the dynamic equilibrium of the system allows for increased reductant storage in some catalyst systems where excess reductant is present.
  • AU examples are provided for purposes of illustration only, and are not considered to be limiting.
  • the degradation module 202 further defines a first compensation region 224, a second compensation region 226, and an efficient catalyst region 228 on a space-velocity temperature map 222 in response to the catalyst degradation value 210.
  • the degradation module 202 further determines the adjusted reductant value 208 as a value higher than the nominal reductant value 212 in the first compensation region 224 and as a value lower than the nominal reductant value 212 in the second compensation region 226. In certain embodiments, the degradation module 202 does not adjust the nominal reductant value 212 when operating conditions are in the efficient catalyst region 228.
  • the injection amount module 204 interprets a nominal reductant value 212 comprising a nominal reductant to NO x ratio.
  • the nominal reductant to NO x ratio may be a molar ratio of reductant to NO x .
  • Interpreting the nominal reductant value 212 includes reading the nominal reductant value 212 from a memory location, from a user input, over a datalink, and/or determining the nominal reductant value 212 based on other parameters in the system 100.
  • the nominal reductant value 212 is a value of reductant to NO x ratio that would be utilized in the absence of catalyst degradation compensation, and is not necessarily a single or static value.
  • the nominal reductant value 212 may be a dynamic value based on various parameters in the system 100 including, but not limited to, an NO:N ⁇ 2 ratio in the exhaust stream, an amount OfNO x in the exhaust stream, the present temperature of the aftertreatment catalyst 102 and/or exhaust stream 104, and the current space velocity of the aftertreatment catalyst 102 based on the present exhaust stream 104 flow rate and amount of catalyst in the aftertreatment catalyst 102.
  • the degradation compensation module 206 determines an adjusted reductant value 208 in response to the catalyst degradation value 210 and the nominal reductant value 212.
  • the adjusted reductant value 208 is determined as a value to achieve similar results to the nominal reductant value 212 in a non-degraded catalyst, and/or a value to achieve at least a minimal set of results for emissions or other purposes.
  • the degradation compensation module 206 determines the adjusted reductant value 208 as a value that provides a NO x reduction amount achievable by a non- degraded catalyst with the nominal reductant value 212.
  • the degradation compensation module 206 determines the adjusted reductant value 208 as a value that provides a NO x reduction amount achievable by a non-degraded catalyst with the nominal reductant value limited by an ammonia slip amount 230.
  • the degradation compensation module 206 determines the adjusted reductant value 208 as a value that provides at least a minimum NO x reduction amount 232. In another example, the degradation compensation module 206 determines the adjusted reductant value 208 as a value that does not exceed an ammonia slip amount 230. Examples are provided for illustration only and are not considered limiting.
  • interpreting a nominal reductant value includes determining a nominal reductant to NO x ratio, and determining an adjusted reductant value includes determining an adjusted reductant to NO x ratio.
  • the adjusted reductant value is an adjusted reductant to NO x ratio.
  • the adjusted reductant to NO x ratio may be a value between 0.5 and 1.6.
  • the adjusted reductant to NO x ratio is a value greater than 0.3, a value less than 3, and/or a value less than 5.
  • the NO x conversion will not be greater than the NO x ratio, so a NO x ratio of 0.3 provides about 30% maximum conversion OfNO x (which may not be fully achieved) .
  • S ome benefits in NO x conversion continue with ratios of 3 : 1 , 5 : 1 , or even greater.
  • an effective ammonia oxidation catalyst 122 is present, or where avoidance of NO x is more important than slip of ammonia, higher reductant to NO x ratios may be indicated.
  • the controller 120 includes an injection control module 214 that provides an injection rate signal 216 based on the adjusted reductant value 208.
  • the injection rate signal 216 may be a parameter determined from the adjusted reductant value 208, and may be otherwise adjusted due to injector dynamics, unit conversions, system limitations, or for other adjustments known in the art.
  • Fig. 3 is an illustration of a space- velocity temperature map for a non-degraded catalyst.
  • the regions 302, 304, 306, 308, 310 illustrated are regions of decreasing NO x conversion efficiency, in the order listed where the region 302 is a highest efficiency and the region 310 is a lowest efficiency.
  • FIG. 4 an illustration of a space-velocity temperature map for a degraded catalyst is illustrated.
  • the region 406 is an illustration of the region 302 of highest efficiency from the non-degraded catalyst of Fig. 3. In the example shown, the highest efficiency region 302 occurs at a lower temperature in the degraded catalyst than in the non-degraded catalyst.
  • a first compensation region 224 is illustrated and a second compensation region 226 is illustrated.
  • the adjusted reductant value 208 may be higher than the nominal reductant value 212 in the first compensation region 224, and the adjusted reductant value 208 may be lower than the nominal reductant value 212 in the second compensation region 226.
  • the responses illustrated are for example purposes only, and the emissions and degraded catalyst behaviors for a given embodiment of the system 100 determine specific responses for the system 100.
  • the determination of efficiency contours 302, 304, 306, 308, 310, the number of contours, and the thresholds for contours are mechanical steps for one of skill in the art with the benefit of the disclosures herein.
  • the region 302 of Fig. 4 may be an efficient catalyst region 228, and in certain embodiments within the efficient catalyst region the adjusted reductant value 208 may be equivalent to the nominal reductant value 212.
  • the positioning of the efficient catalyst region 228, where present, is a decision based upon the catalyst efficiencies of the system 100 that allow the degraded catalyst to operate similarly to a non-degraded catalyst and still meet design criteria. In certain embodiments, the positioning of the efficient catalyst region 228 may significantly differ from the region 302.
  • Fig. 5 is an illustration of catalyst degradation values 210 as a function of temperature.
  • the curve 502 illustrates a NO x conversion efficiency at a first relatively low temperature and the curve 504 illustrates a NO x conversion efficiency at a second relatively high temperature over a range of degradation values 210.
  • the units of the degradation value 210 scale may be of any available degradation description, including a damage index, an amount of time spent above a threshold temperature, a number of damage events that have occurred (for example a number of high, temperature regeneration events), or any other parameter known in the art.
  • a catalyst is exposed to an aging or damage process, and the NO x conversion efficiency for the catalyst is tracked with the damage to build curves 502, 504 such as those illustrated in Fig. 5.
  • the degradation compensation module 206 utilizes curves such as those illustrated in Fig. 5 to determine the adjusted reductant value 208 based on the nominal reductant value 212.
  • Fig. 6 is an alternate illustration of catalyst degradation values 210 as a function of temperature.
  • a reductant to NO x ratio is plotted against temperature for a plurality of catalyst degradation values 210.
  • the curve 602 illustrates the nominal reductant value 212 for a non-degraded catalyst
  • the curves 604, 606, 608 illustrate adjusted reductant values 208 for the catalyst at various levels of degradation.
  • the curve 604 represents a catalyst with 25 hours spent over a threshold temperature
  • the curve 606 represents a catalyst with IOO hours spent over the threshold temperature
  • the curve 608 represents a catalyst with 200 hours spent over the threshold temperature.
  • the degradation compensation module 206 utilizes curves such as those illustrated in Fig.
  • a number of curves 602, 604, 606, 608 are stored on the controller 120 and the degradation compensation module 206 interpolates between curves 602, 604, 606, 608 based upon the catalyst degradation value 210 compared to the catalyst degradation values associated with the curves 602, 604, 606, 608.
  • Fig. 7 is a schematic flow diagram of a procedure 700 for compensating for catalyst degradation.
  • the procedure 700 includes an operation 702 to provide an aftertreatment catalyst disposed in an exhaust stream of an internal combustion engine and an operation 704 to provide a reductant that reacts with an amount of NO x in the exhaust stream in the presence of the aftertreatment catalyst.
  • the procedure 700 further includes an operation 706 to interpret a catalyst degradation value corresponding to the aftertreatment catalyst, and an operation 708 to interpret a nominal reductant value.
  • the procedure 700 further includes an operation 710 to determine an adjusted reductant value in response to the catalyst degradation value and the nominal reductant value.
  • the procedure 700 further includes an operation 712 to inject the reductant into the exhaust stream at a rate based on the adjusted reductant value.
  • Fig. 8 is a schematic flow diagram of an alternate procedure 800 for compensating for catalyst degradation.
  • the procedure 800 includes an operation 802 to interpret a catalyst degradation value corresponding to an aftertreatment catalyst, and an operation 804 to interpret a nominal reductant value comprising a nominal reductant to NO x ratio.
  • the procedure 800 further includes an operation 806 to determine an adjusted reductant value in response to the catalyst degradation value and the nominal reductant value.
  • the procedure 800 further includes an operation 818 to provide an injection rate signal based on the adjusted reductant value, and an operation 820 to inject an amount of reductant into an exhaust stream in response to the injection rate signal.
  • the procedure 800 includes an operation 808 to select an adjustment method for determining the adjusted reductant value.
  • An adjustment method "A” includes an operation 810 to determine an adjusted reductant value that provides a NOx reduction amount achievable by a non-degraded catalyst with the nominal reductant value.
  • An adjustment method “B” includes an operation 812 to determine an adjusted reductant value that provides a NOx reduction amount achievable by a non-degraded catalyst with the nominal redt ⁇ ctant value limited by an ammonia slip amount.
  • An adjustment method “C” includes an operation 814 to determine an adjusted reductant value that provides at least a minimum NOx reduction amount.
  • An adjustment method “D” includes an operation 816 to determine an adjusted reductant value that provides an adjusted reductant value that does not exceed an ammonia slip amount.
  • One exemplary embodiment is a method including providing an aftertreatment catalyst disposed in an exhaust stream of an internal combustion engine and providing a reductant that reacts with an amount of NO x in the exhaust stream in the presence of the aftertreatment catalyst.
  • the method further includes interpreting a catalyst degradation value corresponding to the aftertreatment catalyst, interpreting a nominal reductant value, and determining an adjusted reductant value in response to the catalyst degradation value and the nominal reductant value.
  • the method further includes injecting the reductant into the exhaust stream at a rate based on the adjusted reductant value.
  • the reductant includes urea, ammonia, and/or a hydrocarbon.
  • the catalyst degradation value includes a NO x conversion efficiency value and/or a reductant storage value.
  • the catalyst degradation value further includes a function of a temperature of the aftertreatment catalyst, and/or a function of a space velocity of the exhaust stream in the aftertreatment catalyst.
  • the nominal reductant value includes a molar ratio of the reducta ⁇ t to the amount of NO x .
  • interpreting a nominal reductant value includes determining a nominal reductant to NO x ratio, and determining an adjusted reductant value includes determining an adjusted reductant to NO x ratio.
  • the adjusted reductant value is an adjusted reductant to NO x ratio, and is a value between 0.5 and 1.6, a value greater than 0.3, a value less than 3, and/or a value less than 5.
  • Another exemplary embodiment is a system including an aftertreatment catalyst disposed in an exhaust stream of an internal combustion engine, a reductant that reacts with an amount of NO x in the exhaust stream in the presence of the aftertreatment catalyst, and an injector structured to inject the reductant into the exhaust stream at a position upstream of the aftertreatment catalyst.
  • the system may include a controller having modules structured to functionally execute operations to compensate for catalyst degradation.
  • the controller includes a degradation module, an injection amount module, and a degradation compensation module.
  • the degradation module interprets a catalyst degradation value corresponding to the aftertreatment catalyst, the injection amount module interprets a nominal reductant value comprising a nominal reductant to NO x ratio, and the degradation compensation module determines an adjusted reductant value in response to the catalyst degradation value and the nominal reductant value.
  • the controller includes an an injection control module that provides an injection rate signal based on the adjusted reductant value.
  • the system further includes an injector that injects the reductant into the exhaust stream at a position upstream of the aftertreatment catalyst in response to the injection rate signal.
  • the catalyst degradation value includes a NO x conversion efficiency value and/or a reductant storage value.
  • the catalyst degradation value may be a function of a temperature of the aftertreatment catalyst and/or a function of a space velocity of the exhaust stream in the aftertreatment catalyst.
  • the degradation module further defines a first compensation region, a second compensation region, and an efficient catalyst region on a space- velocity temperature map in response to the catalyst degradation value, and further determines the adjusted reductant value as a value higher than the nominal reductant value in the first compensation region and as a value lower than the nominal reductant value in the second compensation region.
  • the degradation compensation module further determines the adjusted reductant value according to at least one of the following schemes: determining an adjusted reductant value that provides a NOx reduction amount achievable by a non- degraded catalyst with the nominal reductant value, determining an adjusted reductant value that provides a NOx reduction amount achievable by a non-degraded catalyst with the nominal reductant value limited by an ammonia slip amount, determining an adjusted reductant value that provides at least a minimum NOx reduction amount, and determining an adjusted reductant value that does not exceed an ammonia slip amount.
  • Yet another exemplary embodiment is an apparatus including a degradation module that interprets a catalyst degradation value corresponding to an aftertreatment catalyst, an injection amount module that interprets a nominal reductant value including a nominal reductant to NO x ratio, a degradation compensation module that determines an adjusted reductant value in response to the catalyst degradation value and the nominal reductant value, and an injection control module that provides an injection rate signal based on the adjusted reductant value.
  • the degradation module may further define a first compensation region, a second compensation region, and an efficient catalyst region on a space-velocity temperature map in response to the catalyst degradation value.
  • the degradation compensation module further determines the adjusted reductant value as a value higher than the nominal reductant value in the first compensation region, and determines the adjusted reductant value as a value lower than the nominal reductant value in the second compensation region.
  • One exemplary embodiment is a method that includes interpreting a catalyst degradation value corresponding to an aftertreatment catalyst, interpreting a nominal reductant value comprising a nominal reductant to NO x ratio, determining an adjusted reductant value in response to the catalyst degradation value and the nominal reductant value, providing an injection rate signal based on the adjusted reductant value, and injecting an amount of reductant into an exhaust stream in response to the injection rate signal.
  • the method further includes determining an adjusted reductant value that provides a NOx reduction amount achievable by a non-degraded catalyst with the nominal reductant value, determining an adjusted reductant value that provides a NOx reduction amount achievable by a non-degraded catalyst with the nominal reductant value limited by an ammonia slip amount, determining an adjusted reductant value that provides at least a minimum NOx reduction amount, and determining an adjusted reductant value that does not exceed an ammonia slip amount.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Exhaust Gas After Treatment (AREA)

Abstract

L'invention concerne, selon un mode de réalisation, un procédé consistant à utiliser un catalyseur post-traitement disposé dans un courant d'échappement d'un moteur à combustion interne et un agent réducteur qui réagit avec une quantité donnée de NOx dans le courant d'échappement en présence dudit catalyseur. Le procédé consiste à interpréter une valeur de dégradation du catalyseur correspondant audit catalyseur, et à interpréter une valeur nominale de l'agent réducteur. Le procédé consiste en outre à déterminer une valeur ajustée de l'agent réducteur en réponse à la valeur de dégradation du catalyseur et à la valeur nominale de l'agent réducteur, et à injecter l'agent réducteur dans le courant d'échappement à un débit calculé sur la base de la valeur ajustée de l'agent réducteur.
PCT/US2010/024954 2009-02-23 2010-02-22 Compensation de la dégradation d'un catalyseur post-traitement WO2010096782A2 (fr)

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Application Number Priority Date Filing Date Title
US13/215,162 US20120067028A1 (en) 2010-02-22 2011-08-22 Aftertreatment catalyst degradation compensation

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US15456109P 2009-02-23 2009-02-23
US61/154,561 2009-02-23

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WO2010096782A3 WO2010096782A3 (fr) 2011-01-27

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WO2015130647A1 (fr) * 2014-02-25 2015-09-03 Cummins Inc. Commande de papillon des gaz d'échappement pour gestion thermique de système de post-traitement
US20230028415A1 (en) * 2021-07-23 2023-01-26 Robert Bosch Gmbh Method, computing unit and computer program for operating an scr catalytic converter

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US20060242945A1 (en) * 2005-05-02 2006-11-02 Wang Yue Y Method and apparatus for diagnosing exhaust gas aftertreatment component degradation
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WO2008149213A1 (fr) * 2007-06-08 2008-12-11 Toyota Jidosha Kabushiki Kaisha Appareil de purification du gaz d'échappement d'un moteur à combustion interne et procédé servant à contrôler celui-ci

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US20040175305A1 (en) * 2003-03-07 2004-09-09 Honda Motor Co., Ltd. Exhaust gas purification system
US20060242945A1 (en) * 2005-05-02 2006-11-02 Wang Yue Y Method and apparatus for diagnosing exhaust gas aftertreatment component degradation
US20080022658A1 (en) * 2006-07-25 2008-01-31 Gm Global Technology Operations, Inc. Method and Apparatus for Monitoring a Urea Injection System in an Exhaust Aftertreatment System
KR20080030163A (ko) * 2006-09-29 2008-04-04 현대자동차주식회사 차량 배기계 선택적 촉매장치의 제어 시스템 및 그제어방법
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015130647A1 (fr) * 2014-02-25 2015-09-03 Cummins Inc. Commande de papillon des gaz d'échappement pour gestion thermique de système de post-traitement
US9212587B2 (en) 2014-02-25 2015-12-15 Cummins Inc. Exhaust throttle control for aftertreatment system thermal management
CN106102871A (zh) * 2014-02-25 2016-11-09 卡明斯公司 用于后处理系统热管理的排气节流阀控制
CN106102871B (zh) * 2014-02-25 2019-12-03 卡明斯公司 用于后处理系统热管理的排气节流阀控制
US20230028415A1 (en) * 2021-07-23 2023-01-26 Robert Bosch Gmbh Method, computing unit and computer program for operating an scr catalytic converter

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