US20090000278A1 - Addition-amount controller for exhaust gas purifying agent and exhaust emission control system - Google Patents

Addition-amount controller for exhaust gas purifying agent and exhaust emission control system Download PDF

Info

Publication number
US20090000278A1
US20090000278A1 US12/146,829 US14682908A US2009000278A1 US 20090000278 A1 US20090000278 A1 US 20090000278A1 US 14682908 A US14682908 A US 14682908A US 2009000278 A1 US2009000278 A1 US 2009000278A1
Authority
US
United States
Prior art keywords
exhaust gas
amount
addition
catalyst
mode
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.)
Abandoned
Application number
US12/146,829
Other languages
English (en)
Inventor
Ataru Ichikawa
Tutomu Nakamura
Osamu Shimomura
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.)
Denso Corp
Soken Inc
Original Assignee
Denso Corp
Nippon Soken Inc
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 Denso Corp, Nippon Soken Inc filed Critical Denso Corp
Assigned to NIPPON SOKEN, INC., DENSO CORPORATION reassignment NIPPON SOKEN, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ICHIKAWA, ATARU, NAKAMURA, TUTOMU, SHIMOMURA, OSAMU
Publication of US20090000278A1 publication Critical patent/US20090000278A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86—Catalytic processes
    • B01D53/90—Injecting reactants
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9495—Controlling the catalytic process
    • 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
    • F01N13/009—Exhaust or silencing apparatus characterised by constructional features having two or more separate purifying devices arranged in series
    • 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
    • F01N3/206—Adding periodically or continuously substances to exhaust gases for promoting purification, e.g. catalytic material in liquid form, NOx reducing agents
    • F01N3/208—Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2251/00—Reactants
    • B01D2251/20—Reductants
    • B01D2251/206—Ammonium compounds
    • B01D2251/2062—Ammonia
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2258/00—Sources of waste gases
    • B01D2258/01—Engine exhaust gases
    • B01D2258/012—Diesel engines and lean burn gasoline engines
    • 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
    • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/02—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor
    • F01N2560/026—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor for measuring or detecting NOx
    • 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
    • F01N2570/00—Exhaust treating apparatus eliminating, absorbing or adsorbing specific elements or compounds
    • F01N2570/18—Ammonia
    • 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
    • F01N2610/02—Adding substances to exhaust gases the substance being ammonia or urea
    • 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
    • F01N2610/14—Arrangements for the supply of substances, e.g. conduits
    • 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
    • F01N2610/14—Arrangements for the supply of substances, e.g. conduits
    • F01N2610/1406—Storage means for substances, e.g. tanks or reservoirs
    • 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
    • F01N2610/14—Arrangements for the supply of substances, e.g. conduits
    • F01N2610/1453—Sprayers or atomisers; Arrangement thereof in the exhaust apparatus
    • F01N2610/146—Control thereof, e.g. control of injectors or injection valves
    • 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
    • F01N2900/08—Parameters used for exhaust control or diagnosing said parameters being related to the engine
    • 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
    • F01N2900/16—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

Definitions

  • the present invention relates to an addition-amount controller for an exhaust gas purifying agent, for controlling an amount of addition of NH 3 for purifying exhaust gas by reaction with NO x in the exhaust gas.
  • the invention also relates to an exhaust emission control system e.g., a urea-SCR system, for purifying exhaust gas by an exhaust gas purifying reaction based on NH 3 on a catalyst.
  • urea-SCR selective reduction
  • urea-SCR selective reduction
  • post treatment techniques of exhaust gas for purifying and reducing NO x (nitrogen oxides) in the exhaust gas are classified into two important trends, namely, the above-mentioned urea-SCR system, and a NO x storage-reduction catalyst.
  • the urea-SCR system is already put into practical use in large trucks, and known to have a high purification ratio of a maximum of about “90%”.
  • JP-A-2003-293739 is known as a specific example of such a urea-SCR system.
  • This system mainly includes a catalyst for promoting a specific exhaust gas purifying reaction (reduction reaction of NO x ), an exhaust pipe for guiding the exhaust gas discharged from an exhaust gas generating source (for example, an internal combustion engine) to the catalyst, and a urea water addition valve disposed at a midway point of the exhaust pipe for injecting and adding the urea aqueous solution (additive) to the exhaust gas flowing in the exhaust pipe.
  • an exhaust gas generating source for example, an internal combustion engine
  • the system with this arrangement is configured to inject and add the urea aqueous solution into the exhaust gas by the urea water addition valve, and to supply the urea aqueous solution to the catalyst on the downstream side together with the exhaust gas, using a flow of the exhaust gas.
  • the urea aqueous solution thus supplied is hydrolyzed by exhaust gas heat or the like to generate NH 3 (ammonia), as represented by the following chemical equation: (NH 2 ) 2 CO+H 2 O ⁇ 2NH 3 +CO 2 . This leads to a reduction reaction of NO x by the NH 3 on the catalyst, through which the exhaust gas is purified.
  • the catalyst used in such purification of the exhaust gas generally promotes the reduction reaction of NO x in a temperature range exceeding an activation temperature (critical reaction temperature) inherent to the catalyst, that is, a temperature range having the activation temperature as the lower limit.
  • an activation temperature critical reaction temperature
  • the system as disclosed in JP-A-2003-293739 cannot have a sufficient capacity of purifying the exhaust gas when the catalyst is at a low temperature below the activation temperature.
  • the inventors of the present application take into consideration the facts that the general catalyst for purifying the exhaust gas used in a vehicle-mounted internal combustion engine or the like can store NH 3 and that the larger the amount of the stored NH 3 , the lower the activation temperature (critical reaction temperature) of the catalyst.
  • the inventors now conduct various studies on and have developed an addition-amount controller for an exhaust gas purifying agent so as to improve an exhaust gas purification capacity using a decrease in activation temperature (critical reaction temperature) due to the storage of NH 3 .
  • an exhaust gas purification capacity largely changes according to timing of storing NH 3 by addition of the exhaust gas purifying agent.
  • the temperature of portions around the internal combustion engine including the catalyst become sufficiently high due to the combustion caused by previous acceleration of the engine.
  • the temperature of the catalyst remains at a temperature above the activation temperature for a while.
  • the present invention has been made in view of the forgoing facts, and it is an object of the invention to provide an addition-amount controller for an exhaust gas purifying agent, which can obtain a high exhaust gas purification capacity in response to more conditions, and an exhaust emission control system which can exhibit the high exhaust gas purification capacity by using the addition-amount controller.
  • an addition-amount controller for an exhaust gas purifying agent is configured to be applied to an exhaust emission control system for purifying exhaust gas emitted from an internal combustion engine.
  • the exhaust emission control system includes a catalyst for promoting a specific exhaust gas purification reaction in a temperature range having a critical reaction temperature as a lower limit, and an addition valve for adding an additive of NH 3 (ammonia) or an additive serving as a generating source of the NH 3 to the catalyst itself or the exhaust gas on an upstream side with respect to the catalyst, the additive being adapted to purify NO x (nitrogen oxides) in the exhaust gas by the exhaust gas purification reaction on the catalyst.
  • the addition-amount controller is adapted to control an amount of addition by the addition valve, and the catalyst has properties of storing NH 3 and further decreasing the critical reaction temperature as the amount of NH 3 storage is increased.
  • the addition-amount controller includes: mode selection means for selecting one mode to be executed at that time based on satisfaction of an execution condition for each mode, from among a plurality of control modes, the control modes including a purification control mode in which the addition amount by the addition valve is determined according to a predetermined parameter associated with an amount of NO x in the exhaust gas, and a storage control mode in which the addition amount by the addition valve is set to be larger than that in the purification control mode; and condition determining means for determining whether a rotation speed of an output shaft of the internal combustion engine is decelerated from a higher speed state than an allowable level.
  • the execution condition of the storage control mode is set to be satisfied after a predetermined dissatisfaction time period from start of the deceleration when the condition determining means determines that the rotation speed is decelerated from the higher speed state.
  • the addition-amount controller includes: mode selection means for selecting one mode to be executed at that time based on satisfaction of an execution condition for each mode, from among a plurality of control modes, the control modes including a purification control mode in which the addition amount by the addition valve is determined according to a predetermined parameter associated with an amount of NO x in the exhaust gas, and a storage control mode in which the addition amount by the addition valve is set to be larger than that in the purification control mode; and condition determining means for determining whether an amount of fluctuation in a load on the output shaft of the internal combustion engine toward a negative side is larger than an allowable level.
  • the execution condition of the storage control mode is set to be satisfied after a predetermined dissatisfaction time period from the fluctuation when the condition determining means determines that the amount of fluctuation in the load toward the negative side is larger than the allowable level.
  • the addition-amount controller includes: mode selection means for selecting one mode to be executed at that time based on satisfaction of an execution condition for each mode, from among a plurality of control modes, the control modes including a purification control mode in which the addition amount by the addition valve is determined according to a predetermined parameter associated with an amount of NO x in the exhaust gas, and a storage control mode in which the addition amount by the addition valve is set to be larger than that in the purification control mode; and condition determining means for determining whether an amount of fluctuation in the rotation speed of the output shaft of the internal combustion engine toward the negative side is larger than an allowable level.
  • the execution condition of the storage control mode is set to be satisfied after a predetermined dissatisfaction time period from the fluctuation when the condition determining means determines that the amount of fluctuation in the rotation speed toward the negative side is larger than the allowable level.
  • the addition-amount controller includes: mode selection means for selecting one mode to be executed at that time based on satisfaction of an execution condition for each mode, from among a plurality of control modes, the control modes including a purification control mode in which the addition amount by the addition valve is determined according to a predetermined parameter associated with an amount of NO x in the exhaust gas, and a storage control mode in which the addition amount by the addition valve is set to be larger than that in the purification control mode; and condition determining means for determining whether fuel cut is performed in the internal combustion engine. Furthermore, the execution condition of the storage control mode is set to be satisfied after a predetermined dissatisfaction time period from start of the fuel cut when the condition determining means determines that the fuel cut is performed.
  • the amount of NH 3 for effectively purifying NO x in the exhaust gas is different from an amount of NH 3 that is appropriate to be stored (and an amount of addition by the addition valve, appropriate to be stored). This is because when storing of NH 3 , the amount of NH 3 to be further stored is needed in addition to the amount of NH 3 to be consumed for purifying the NO x . Any one controller of the above first to fourth aspects of the invention is made taking into consideration this fact with the above-mentioned property of the catalyst that the larger the amount of stored NH 3 , the lower the critical reaction temperature.
  • Such a controller can enhance the purification capacity of the catalyst at a low temperature by decreasing the critical reaction temperature of the catalyst through execution of the above-mentioned storage control mode. Further, at the time of deceleration or the like when the catalyst is supposed to be in a high temperature state, or in a similar situation thereto, the mode selection means does not start storing of NH 3 immediately in deceleration of the internal combustion engine to be purified, in a decrease of load on the engine, or in start of the fuel cut. However, the mode selection means starts the storing of NH 3 after a predetermined dissatisfaction time period that can be set, for example, by the time, the temperature of the catalyst, or the like.
  • the controller according to any one aspect of the above first to fourth aspects of the present invention can suitably suppress the deterioration of the emission characteristics, while reducing the deterioration of the emission characteristics due to the exertion of the unnecessary storage of the NH 3 .
  • the temperature of the catalyst has an influence on the property of the catalyst (for example, a limit NH 3 storage amount, or the like). Further, it is known that the higher the temperature of the catalyst, the less the limit storage amount of NH 3 (limit NH 3 storage amount). Thus, when the catalyst temperature is sufficiently low, an allowance degree up to the limit NH 3 storage amount is large, which may require more storage of NH 3 . As mentioned above, when the catalyst is at a low temperature, the activation temperature (critical reaction temperature) of the catalyst is strongly required to be decreased. In view this point, the addition-amount controller may be further provided with catalyst temperature determination means for determining whether the temperature of the catalyst at that time is lower than an allowable level. In this case, the predetermined dissatisfaction time period has end timing at which the catalyst temperature determination means determines that the temperature of the catalyst is lower than the allowable level.
  • the catalyst temperature determination means determines that the temperature of the catalyst at that time is lower than the allowable level.
  • the execution condition of the purification control mode may be set to be satisfied when the execution condition of the storage control mode is not satisfied.
  • the mode selection means switches between two types of the control modes of the purification control mode and the storage control mode according to satisfaction or dissatisfaction of the execution condition.
  • an addition-amount controller for an exhaust gas purifying agent is configured to be applied to an exhaust emission control system for purifying exhaust gas emitted from an internal combustion engine.
  • the exhaust emission control system includes a catalyst for promoting a specific exhaust gas purification reaction in a temperature range having a critical reaction temperature as a lower limit, and an addition valve for adding an additive of NH 3 (ammonia) or an additive serving as a generating source of the NH 3 to the catalyst itself or the exhaust gas on an upstream side with respect to the catalyst, the additive being adapted to purify NO x (nitrogen oxides) in the exhaust gas by the exhaust gas purification reaction on the catalyst.
  • the addition-amount controller is adapted to control an amount of addition by the addition valve, and the catalyst has properties of storing NH 3 and further decreasing the critical reaction temperature as the amount of NH 3 storage is increased. Furthermore, the addition-amount controller includes: operating mode determination means for determining whether the operating mode of the internal combustion engine is a preset operating mode in which a load on the output shaft of the internal combustion engine is controlled to be decreased when the catalyst is at a high temperature exceeding the critical reaction temperature; and prohibition means for prohibiting addition of NH 3 or the additive serving as the generating source of NH 3 by the addition valve to the catalyst in the amount of storing NH 3 , during a predetermined time period, when the operating mode determination means determines that the operating mode at that time is the preset operating mode.
  • the temperature of the catalyst is supposed to be at the high temperature.
  • the storage of NH 3 (specifically, addition for the purpose of storage) is prohibited for the predetermined time period, for example, while the catalyst temperature is sufficiently high. This can suitably suppress deterioration of the emission characteristics, while reducing a decrease in purification ratio of NO x due to the execution of the unnecessary storage of NH 3 .
  • the addition valve may be adapted to inject and add a urea aqueous solution as the additive to the exhaust gas on an upstream side with respect to the catalyst.
  • the urea aqueous solution is injected and added to the exhaust gas on the upstream side with respect to the catalyst, so that the urea is hydrolyzed by exhaust gas heat or the like until the urea reaches the catalyst to form NH 3 .
  • This can supply more NH 3 (purifying agent) to the catalyst.
  • FIG. 1 is a schematic diagram showing an addition-amount controller for an exhaust gas purifying agent, and an exhaust emission control system with the addition-amount controller, according to one embodiment of the invention
  • FIG. 2 is a flowchart showing control processing for controlling an amount of addition of urea water
  • FIG. 3 is a flowchart showing control processing for determining start timing of an engine deceleration time period
  • FIG. 4 is a flowchart showing control processing for determining end timing of the engine deceleration time period
  • FIG. 5 is a graph showing an example of a map used for calculation of a limit NH 3 storage amount
  • FIG. 6 is a graph showing an example of a relationship between the critical reaction temperature of a SCR catalyst and the NH 3 storage amount
  • FIG. 7 is a graph showing an example of a purifying property of the SCR catalyst
  • FIGS. 8A to 8C are timing charts showing one form of urea water addition control according to the embodiment.
  • FIG. 9 is a flowchart showing another example of control processing regarding mode selection.
  • the exhaust emission control system of this embodiment has the basic structure used in a general urea-SCR (selective reduction) system, as an example.
  • NH 3 ammonia generated from a urea ((NH 2 ) 2 CO) aqueous solution (hereinafter referred to as a urea water) reduces (purifies) NO x in exhaust gas.
  • FIG. 1 is a diagram schematically showing the structure of a urea-SCR system (exhaust gas purification device) according to this embodiment.
  • this system is adapted to purify exhaust gas emitted from a diesel engine (exhaust gas generating source) mounted on, for example, a four-wheeled vehicle (not shown).
  • the system mainly includes various actuators and sensors for purifying the exhaust gas, and an ECU (electronic control unit) 40 .
  • the engine of this embodiment (engine of interest) is supposed to be a multi-cylinder engine (for example, inline four-cylinder engine) mounted on the four-wheeled vehicle (for example, an automatic car).
  • Each cylinder is provided with an injector having a fuel injection valve. Fuel supplied to each cylinder by the injector burns off in the corresponding cylinder.
  • the engine is the so-called four stroke (4 ⁇ piston stroke) reciprocating diesel engine (internal combustion engine) which is designed to convert energy generated by combustion of the fuel into a rotational operation to rotate an output shaft (crankshaft).
  • the cylinder of interest at that time is sequentially determined by a cylinder determination sensor (electromagnetic pickup) provided in a cam shaft of an air intake and exhaust valve.
  • One combustion cycle consisting of four strokes, namely, suction, compression, combustion, and exhaust, is performed in a cycle of “720° CA” at each of four cylinders # 1 to # 4 .
  • the respective combustion cycles for the four cylinders are sequentially executed at the cylinders # 1 , # 3 , # 4 , and # 2 in that order by shifting the cycle between one cylinder and the next cylinder by 180° CA”.
  • various exhaust gas purification devices are disposed in the exhaust emission control system to form an exhaust gas purification system.
  • the exhaust gas purification devices include a diesel particulate filter (DPF) 11 , an exhaust gas pipe (exhaust gas passage) 12 , a SCR catalyst 13 , an exhaust gas pipe (exhaust gas passage) 14 , and a NH 3 catalyst (for example, oxidation catalyst) 15 disposed from the upstream side of the exhaust gas (on the engine side which is an exhaust gas generating source) in that order.
  • a urea water addition valve 16 is disposed such that an injection port 16 a opens toward the downstream side of the exhaust gas.
  • the urea water addition valve 16 is adapted to add (inject and supply) the urea water pressure-fed into a urea water tank 17 a to the downstream part with respect to the DPF 11 .
  • the urea water addition valve 16 is a so-called electromagnetic driven injection valve whose driving is electrically controlled by the ECU 40 .
  • the addition valve 16 is controlled by the ECU 40 so that the urea water serving as an additive is injected and supplied by a desired addition amount to the exhaust gas flowing in the exhaust gas pipe 12 between the DPF 11 and the SCR catalyst 13 .
  • the urea water added or NH 3 after decomposition
  • exhaust gas flow exhaust gas flow
  • addition of the urea water through the urea water addition valve 16 generates the NH 3 (purifying agent) based on the urea water as indicated by the following decomposition reaction (formula 1) in the exhaust gas.
  • the following NO x reduction reaction (as indicated by the following formula 2) is performed by use of NH 3 on the SCR catalyst 13 , thereby purifying the exhaust gas (purifying NO x ) to be purified.
  • the temperature of the exhaust gas on the downstream side of the SCR catalyst 13 and the amount of NO x (i.e., NO x emission amount) contained in the exhaust gas can be detected (specifically, can be calculated by the ECU 40 based on outputs from the sensors) by an exhaust gas sensor 14 a (incorporating therein a NO x sensor and a temperature sensor) provided in the exhaust gas pipe 14 .
  • the DPF 11 is a continuously regenerated filter for particulate matter PM removal, that is, for collecting particulate matter (PM) in the exhaust gas.
  • the DPF 11 can be continuously used by repeatedly burning and removing (corresponding to a regeneration process) the collected PM in post injection or the like after main injection for mainly generating torque.
  • the DPF 11 supports a platinum-based oxidation catalyst not shown (in this example, the DPF and the oxidation catalyst are integrally formed with each other, but may be formed separately).
  • the SCR catalyst 13 is formed of catalytic metal, such as vanadium oxide (V 2 O 5 ), supported on, for example, a honeycomb structural catalyst carrier.
  • the SCR catalyst 13 has a catalytic action for promoting the reduction reaction (exhaust gas purification reaction) of NO x , that is, the reaction indicated by the above formula 2.
  • the structure of the urea water addition valve 16 is based on that of a fuel injection valve (injector) commonly used in supply of fuel to an engine for a vehicle (internal combustion engine).
  • the structure of the urea water addition valve 16 is well known, and thus will be briefly described below. That is, for convenience of explanation, illustration of an inside structure of the addition valve 16 will be omitted.
  • the urea water addition valve 16 incorporates in a valve body, a needle driving portion formed of an electromagnetic solenoid or the like, and a needle driven by the needle driving portion and reciprocating (moving vertically) in the valve body (housing).
  • the needle is adapted to open and close a necessary number of injection holes formed in an injection port 16 a at the tip of the valve body, or a circulation route to these injection holes.
  • the electromagnetic solenoid When the electromagnetic solenoid is energized, the urea water addition valve 16 with this arrangement (each element) moves in the direction of opening the valve by driving the needle by use of the electromagnetic solenoid according to an electric signal from the ECU 40 (for example, a pulse signal by PWM (Pulse Width Modulation) control), that is, according to an injection command from the ECU 40 .
  • PWM Pulse Width Modulation
  • the injection port 16 a at the tip of the valve body is opened, specifically, at least one of the injection holes at the injection port 16 a is opened, so that the urea water is added (injected) toward the exhaust gas flowing through the exhaust pipe 12 .
  • the amount of addition of the urea water is determined based on an energization time of the electromagnetic solenoid (for example, corresponding to a pulse width of a pulse signal by the ECU 40 ).
  • a urea water supply system for pressure-feeding the urea water to the urea water addition valve 16 mainly includes a urea water tank 17 a, and a pump 17 b. That is, the urea water stored in the urea water tank 17 a is pumped by the pump 17 b disposed in the tank 17 a, and then pressure-fed toward the urea water addition valve 16 . The pressure-fed urea water is sequentially supplied to the urea water addition valve 16 through a pipe 17 c for supply of the urea water.
  • a barrier filter 17 f provided on the upstream side with respect to the addition valve 16 before the urea water is supplied to the urea water addition valve 16 .
  • the pressure of supply of the urea water to the addition valve 16 is controlled by a urea water pressure regulator 17 d. Specifically, when the supply pressure exceeds a predetermined value, a mechanical device using a spring or the like allows the urea water in the pipe 17 c to return to the urea water tank 17 a. In the present system, the supply pressure of the urea water is controlled to remain at the predetermined value (set pressure) based on the action of the regulator 17 d.
  • the supply pressure of the urea water is not controlled precisely to be kept at the set pressure even by the action of such a regulator 17 d.
  • the supply pressure of the urea water can be detected by the urea water pressure sensor 17 e (specifically, calculated by the ECU 40 based on the sensor output) provided in a predetermined detection position (for example, on the downstream side of the regulator 17 d where a fuel pressure is stabilized through the pressure control by the regulator 17 d ).
  • a section for mainly performing control associated with the exhaust gas purification as an electronic control unit in such a system is the ECU 40 (for example, the ECU for control of the purification of exhaust gas connected to an ECU for control of the engine via a CAN or the like), that is, the addition-amount controller for an exhaust gas purifying agent according to this embodiment.
  • the ECU 40 includes a well-known microcomputer (not shown), and operates various types of actuators, such as the urea water addition valve 16 , based on detection signals from the various sensors to perform various types of control operations associated with the exhaust gas purification in the optimal form according to the condition of each time.
  • the microcomputer installed on the ECU 40 basically includes a CPU (central processing unit) for performing various computations, a RAM (random access memory) serving as a main memory for temporarily storing therein data in the middle of the computation, the result of computation, or the like, and a ROM (read-only memory) serving as a program memory.
  • the microcomputer also includes an EEPROM (electrically erasable and programmable read-only memory; electrically erasable programmable nonvolatile memory) serving as a memory for data storage, and a backup RAM (RAM fed by a backup power source, such as a vehicle-mounted battery).
  • the microcomputer includes signal processors, including an A/D converter and a clock generation circuit, various computation devices, such as an input/output port, for inputting and outputting signals with the external element, a storage device, a communication device, and a power supply circuit.
  • the ROM previously stores therein various programs and a control map associated with the control of the exhaust gas purification, including a program associated with control of an addition amount of the exhaust gas purifying agent.
  • the memory for storing data (for example, EEPROM) previously stores therein various kinds of control data or the like, including design data for the engine.
  • NH 3 serving as the purifying agent is added to the exhaust gas in the form of urea aqueous solution (urea water) by the urea aqueous addition valve 16 .
  • the urea water is decomposed in the exhaust gas to form NH 3 , and the NO x reduction reaction (indicated by the formula 2) is performed on the SCR catalyst 13 based on the thus-generated NH 3 to purify the exhaust gas (exhaust gas from the engine) to be purified.
  • the processing shown in FIG. 2 is carried out as the control of an addition amount of the urea water. This processing can obtain the high exhaust gas purification capacity in response to more conditions.
  • the control of the addition amount of the urea water will be described with reference to FIGS. 2 to 8 .
  • FIG. 2 is a flowchart showing the addition-amount control of the urea water.
  • a series of control steps in the processing shown in FIG. 2 is basically performed repeatedly at intervals of a predetermined processing time while a predetermined condition is satisfied by executing the program stored in the ROM by means of the ECU 40 , for example, during the time from the startup of the engine to the stopping of the engine.
  • Values of various parameters used in the processing shown in FIG. 2 are stored in the storage device, such as the RAM or EEPROM mounted on the ECU 40 , as occasion arises, and updated at any time if necessary.
  • step S 10 it is determined whether or not the engine is being accelerated, that is, it is determined whether or not the timing at that time of step S 10 is in an engine deceleration time period.
  • the engine deceleration time period is set by repeatedly performing a routine processing other than the processing shown in FIG. 2 , that is, the series of steps in the processes shown in FIGS. 3 and 4 , stored in the ROM of the ECU 40 , at intervals of the predetermined processing time.
  • the processing shown in FIG. 3 is to determine the start timing of the engine deceleration time period.
  • step S 31 it is determined whether or not the engine is driven at a high speed, specifically, whether or not a rotation speed (engine rotation speed) of the output shaft of the engine is larger than a predetermined determination value (engine rotation speed>determination value). Furthermore, at step S 31 , it is also determined whether or not the engine is being decelerated, specifically, whether or not an accelerator pedal is in a non-operation state (an amount of operation of the accelerator ⁇ 0). The determination at step S 31 is repeatedly performed.
  • the timing at that time is set as the start timing of the engine deceleration time period in the subsequent step S 32 .
  • the above-mentioned engine deceleration time period corresponds to a time period from when the start timing is set at step S 32 to when the end timing is set.
  • fuel cut stopping processing of fuel injection associated with generation of torque
  • processing shown in FIG. 4 is to determine the end timing of the engine deceleration time period.
  • step S 41 it is determined whether or not the engine is being decelerated, that is, whether or not the start timing of the engine deceleration time period is already set in the previous step S 32 shown in FIG. 3 . Only when it is determined that the engine is being decelerated at step S 41 , the processes at step S 42 and the following steps are carried out.
  • step S 42 it is determined whether or not the engine rotation speed at that time is smaller than an allowable level, specifically, whether or not the engine rotation speed is smaller than a predetermined determination value (engine rotation speed ⁇ determination value).
  • the predetermined determination value at step S 42 is not necessarily the same as the determination value at step S 31 .
  • the determination process at step S 42 is repeatedly performed.
  • the engine rotation speed is determined to be smaller than the allowable level (predetermined determination value) at step S 42
  • the engine is determined to be at the low speed, and in the subsequent step S 43 , the timing at that time is set as the end timing of the engine deceleration time period.
  • the engine deceleration time period described above is determined in this way.
  • step S 10 When the time is determined to be in the engine deceleration time period at step S 10 , the processes at step S 11 and the following steps will be carried out. When the time is determined not to be in the engine deceleration time period in the same step S 10 , the procedure will proceed to step S 19 a.
  • the addition-amount controller selects one of a purification control mode and a storage control mode to be carried out.
  • a purification control mode an amount of addition of the urea water by the urea water addition valve 16 is determined according to a predetermined parameter about an NO x amount in the exhaust gas, specifically, the engine rotation speed and the fuel injection amount.
  • an addition amount of the urea water by the urea water addition valve 16 is set to be larger than that in the purification control mode (specifically, only by increasing an amount required to cover a shortfall with respect to a target value of the NH 3 storage amount). That is, while one of the control modes is not performed, the other is performed.
  • the selection of the control mode is performed based on the result of determination by the processes in steps S 10 and S 13 . More specifically, when the necessary condition is determined not to be satisfied in at least one of steps S 10 and S 13 , the storage of NH 3 is determined to be unnecessary, and thus the purification control mode is performed through the processes at steps S 19 a and S 20 . On the other hand, when the necessary conditions are determined to be satisfied in both steps S 10 and S 13 , the storage control mode is performed through the processes in steps S 14 to S 20 so as to store the NH 3 on the SCR catalyst 13 .
  • the purification control mode is performed through the processes in steps S 19 a and S 20 .
  • an addition amount Q of the urea water is obtained according to the engine rotation speed and the fuel injection amount using a reference map (or a mathematical formula) for calculation of a predetermined addition amount of the urea water.
  • This reference map has suitable values (optimal values) of the urea water addition amount Q previously determined and written therein by experiments or the like according to (or in an appropriate manner to) respective values of the engine rotation speed and the fuel injection amount.
  • the map is stored, for example, in the ROM or the like in the ECU 40 .
  • the urea water addition valve 16 is driven (energized only for a time period according to the urea water addition amount Q) based on the urea water addition amount Q thus obtained.
  • an exhaust gas temperature Tex is detected in the subsequent step S 11 .
  • the exhaust gas temperature Tex can be actually measured by the exhaust gas sensor 14 a.
  • the temperature of the SCR catalyst 13 (catalyst temperature Tc) is calculated based on the detected exhaust gas temperature Tex.
  • the catalyst temperature Tc is calculated using, for example, a predetermined map (or a mathematical formula).
  • step S 13 it is determined whether or not the catalyst temperature Tc calculated in the previous step S 12 is smaller than a predetermined determination value Ts (Tc ⁇ Ts).
  • the determination value Ts is variably set, for example, to an occasional critical reaction temperature of each time.
  • the storage control mode is performed through the processes in the following steps S 14 to S 20 so as to store NH 3 in the SCR catalyst 13 .
  • a present NH 3 storage amount ST 1 which is the NH 3 storage amount at that time of the SCR catalyst 13 is obtained.
  • the above NH 3 amount supplied to the SCR catalyst 13 is calculated based on, for example, the addition amount of urea water by the urea water addition valve 16 .
  • the consumption amount of NH 3 on the SCR catalyst 13 is calculated mainly based on the NO x amount emitted from the engine and the purification capacity of the catalyst 13 .
  • the NO x amount emitted from the engine can be calculated based on the predetermined parameter (for example, the engine rotation speed and the fuel injection amount) associated with the operating condition of the engine.
  • the purification capacity of the SCR catalyst 13 reaction rate of the NH 3
  • a limit NH 3 storage amount ST 21 is calculated based on the catalyst temperature Tc calculated in the previous step S 12 .
  • FIG. 5 shows an example of a map used for calculation of the limit NH 3 storage amount ST 21 . This map has suitable values (optimal values) previously written therein by experiments. As shown in FIG. 5 , the limit NH 3 storage amount ST 21 tends to decrease (a NH 3 storage capacity tends to decrease) with an increasing of the catalyst temperature Tc.
  • a necessary NH 3 storage amount (required NH 3 storage amount ST 22 , for example, a fixed value) is obtained so as to obtain a desired temperature as the critical reaction temperature (activation temperature) of the SCR catalyst 13 .
  • the required NH 3 storage amount ST 22 is determined based on the relationship between the critical reaction temperature of the SCR catalyst 13 and the NH 3 storage amount as shown in FIG. 6 (one example provided by experiments or the like by the inventors). As indicated by the solid line RT in FIG. 6 , the critical reaction temperature of the SCR catalyst 13 tends to decrease with increasing NH 3 storage amount.
  • the desired temperature is supposed to be a critical reaction temperature T 1 with respect to the critical reaction temperature T 0 when NH 3 is not stored.
  • the critical reaction temperature T 1 is a temperature lower than “140° C.” which is the catalyst temperature supposed in idling, more specifically, for example, one temperature in a range of “50 to 120° C.”.
  • the critical reaction temperature (activation temperature) of the SCR catalyst 13 is an important parameter for determining the purification property of the SCR catalyst 13 .
  • FIG. 7 is a graph showing an example of the purification property of the SCR catalyst 13 . As shown in FIG. 7 , the NO x purification ratio of the SCR catalyst 13 largely changes at the boundary of the critical reaction temperature.
  • the NO x purification ratio is set to substantially “0”, and the NH 3 storage amount is larger than the NH 3 consumption amount consumed by the purification reaction with NO x .
  • the NO x purification ratio basically becomes larger as increasing catalyst temperature (in particular, drastically changes at a temperature near the critical reaction temperature RT).
  • step S 17 by comparing the limit NH 3 storage amount ST 21 obtained at step S 15 with the required NH 3 storage amount ST 22 obtained at step S 16 , it is determined whether or not the required NH 3 storage amount ST 22 is smaller than the limit NH 3 storage amount ST 21 (ST 21 >ST 22 ).
  • ST 21 >ST 22 the relation of ST 21 >ST 22 is determined to be satisfied at step S 17
  • the above required NH 3 storage amount ST 22 is set as a target NH 3 storage amount ST 2 .
  • step S 172 the above limit NH 3 storage amount ST 21 is set as the target NH 3 storage amount ST 2 .
  • a urea water addition amount Q is obtained using the reference map for calculation of the predetermined urea water addition amount (the same one as that used at step S 19 a ) and the NH 3 storage amount shortfall ⁇ ST at step S 19 b.
  • the urea water addition amount Q in the storage control mode is a urea water addition amount increased so as to cover the NH 3 storage amount shortfall ⁇ ST, as compared to the urea water addition amount in the purification control mode.
  • the urea water addition valve 16 is driven (energized only for a time corresponding to the urea water addition amount Q) based on the urea water addition amount Q thus obtained.
  • FIGS. 8A to 8C are timing charts showing the urea water addition control by taking as an example a case where the vehicle equipped with the exhaust gas purification device and the exhaust emission control system of this embodiment is decelerated from a high speed state.
  • FIG. 8A shows the transition of the engine rotation speed.
  • FIG. 8B shows the transition of the temperature of the SCR catalyst 13 .
  • a device for starting storing of NH 3 at the same time as the start of deceleration (for example, see Japanese Patent Application No. 2000-556137) is used as a comparative example.
  • the operating form of the comparative example is indicated by the solid line L 1 in FIG. 8C
  • the operating form of this embodiment is indicated by the solid line L 2 in FIG. 8C .
  • the following description will be given by comparing both operating forms with each other.
  • the vehicle is driven in the steady state at a high speed until the timing t 1 shown, and starts to decelerate when the driver's foot releases the accelerator pedal at the timing t 1 .
  • the accelerator pedal is determined to be in a non-operating state during the high-speed operation at step S 31 shown in FIG. 3 .
  • the timing of the determination is set as start timing of the engine deceleration time period.
  • the temperature of the SCR catalyst 13 starts to decrease at the timing t 2 that is slightly delayed from the deceleration described above (timing t 1 ).
  • the catalyst temperature Tc is determined to be smaller than the allowable level at step S 13 shown in FIG. 2 .
  • the control mode is switched from the purification control mode to the storage control mode, so that the storage of NH 3 on the SCR catalyst 13 is started.
  • the end timing of the engine deceleration time period (set at step S 43 in FIG. 4 ) is timing after the timing t 3 .
  • the activation temperature of the catalyst 13 (critical reaction temperature) is controlled to an appropriate one (for “ST21>ST22”, to the critical reaction temperature T 1 ).
  • the execution of the storage control mode is not started immediately after the deceleration of the engine, but started after the predetermined dissatisfaction time period. This can suitably suppress the deterioration of the emission characteristics, while reducing the deterioration of the emission characteristics due to the exertion of the unnecessary storage of the NH 3 .
  • the addition-amount controller for an exhaust gas purifying agent and the exhaust emission control system according to this embodiment obtain the following excellent effects and advantages.
  • the addition-amount controller can be suitably applied to the exhaust emission control system for purifying the exhaust gas emitted from the internal combustion engine (engine).
  • the addition-amount controller includes the SCR catalyst 13 having properties of storing NH 3 and further decreasing the critical reaction temperature (activation temperature) as the amount of NH 3 storage is increased (see FIG. 6 ).
  • the SCR catalyst 13 is adapted to promote a specific exhaust gas purification reaction in a temperature range having the critical reaction temperature as the lower limit.
  • the addition-amount controller also includes the urea water addition valve 16 for adding the additive (urea water) serving as a NH 3 (ammonia) generating source to the exhaust gas on the upstream side with respect to the SCR catalyst 13 .
  • the additive is adapted to purify the exhaust gas by the above exhaust gas purification reaction with NO x (nitrogen oxides) in the exhaust gas on the catalyst 13 .
  • the addition-amount controller is adapted to control the amount of addition of the urea water by the urea water addition valve 16 .
  • Such an addition-amount controller for an exhaust gas purifying agent (ECU 40 ) includes a control program (mode selection means, corresponding to steps S 10 and S 13 in FIG. 2 ) for selecting one mode to be executed at that time based on satisfaction of the execution condition for each mode, from among a plurality of control modes, including a purification control mode and a storage control mode.
  • the addition amount of the urea water by the urea water addition valve 16 is determined according to a predetermined parameter associated with the NO x amount of the exhaust gas.
  • the addition amount of the urea water by the urea water addition valve 16 is set to be larger than that in the purification control mode.
  • the addition-amount controller also includes a control program (condition determining means, corresponding to step S 31 in FIG. 3 ) for determining whether or not a rotation speed of an output shaft of the engine (engine rotation speed) is decelerated from a higher speed state than an allowable level.
  • the execution condition of the storage control mode is satisfied after a predetermined dissatisfaction time period (set by the process at step S 13 shown in FIG. 2 ) from start of the deceleration.
  • a predetermined dissatisfaction time period set by the process at step S 13 shown in FIG. 2
  • This can enhance the purification capacity of the catalyst by decreasing the critical reaction temperature of the catalyst through execution of the above-mentioned storage control mode.
  • the storing of NH 3 is not started immediately after the start of deceleration, but after the predetermined dissatisfaction time period (after a time period in which the catalyst temperature becomes lower than the allowable level). This can suitably suppress the deterioration of the emission characteristics, while reducing the deterioration of the emission characteristics due to the exertion of the unnecessary storage of the NH 3 .
  • the NH 3 storage amount of the SCR catalyst 13 is controlled to be the target NH 3 storage amount ST 2 by compensating for the shortfall of the NH 3 storage amount corresponding to a difference between the target NH 3 storage amount ST 2 and the present NH 3 storage amount ST 1 (i.e., NH 3 storage amount shortfall ⁇ ST) by the processing at step S 19 b.
  • the shortfall of the NH 3 storage amount (NH 3 storage amount shortfall ⁇ ST) is compensated, so that the NH 3 storage amount of the SCR catalyst 13 can be set to the target NH 3 storage amount.
  • step S 20 shown in FIG. 2 while a predetermined condition (conditions in steps S 10 and S 13 ) is satisfied, the control of the NH 3 storage amount at steps S 14 to S 20 described above is repeatedly performed.
  • the NH 3 storage amount of the SCR catalyst 13 can be continuously controlled to an appropriate amount with high accuracy while the predetermined condition at steps S 10 and S 13 is satisfied.
  • the activation temperature (i.e., critical reaction temperature) of the catalyst 13 is controlled to an appropriate temperature.
  • the addition-amount controller further includes a control program (catalyst temperature determination means, step S 13 shown in FIG. 2 ) for determining whether or not the temperature of the SCR catalyst 13 at that time (catalyst temperature Tc) is lower than the allowable level.
  • the timing when the temperature of the SCR catalyst 13 is determined to be lower than the allowable level at step S 13 (timing t 3 shown in FIG. 8 ) is set as the end timing of the predetermined dissatisfaction time period. At this end timing, the storage control mode is started. Accordingly, it is possible to store the NH 3 in a limited way in the more demanding condition, that is, when the catalyst temperature is sufficiently low (lower than the allowable level).
  • the determination value Ts used at step S 13 shown in FIG. 2 can be variably set to the critical reaction temperature of each time. That is, at step S 13 , when the catalyst temperature Tc is in a predetermined temperature range (Tc ⁇ Ts) in which the critical reaction temperature (determination value Ts) is the upper limit boundary value, the catalyst temperature Tc is determined to be lower than the allowable level. In this way, the start timing of the NH 3 storage as described above (timing t 3 shown in FIGS. 8A to 8C ) can be set to a more preferable time.
  • the execution condition of the purification control mode is satisfied when the execution condition of the storage control mode is not satisfied. That is, at steps S 10 and S 13 shown in FIG. 2 , two types of control modes, namely, the purification control mode and the storage control mode are switched according to the satisfaction or dissatisfaction of these execution conditions. This can more easily and accurately achieve the control of the exhaust gas purification.
  • This arrangement makes it possible to accurately calculate the amount of increase or decrease in NH 3 storage amount of each time and the present NH 3 amount ST 1 by determination that the remaining NH 3 is stored on the SCR catalyst 13 based on the revenue and expenditure of the NH 3 amount.
  • the amount of consumption of NH 3 on the SCR catalyst 13 is determined based on a predetermined parameter associated with the operating condition of the engine (for example, the engine rotation speed and the fuel injection amount).
  • a predetermined parameter associated with the operating condition of the engine for example, the engine rotation speed and the fuel injection amount.
  • the addition-amount controller also includes a control program (limit storage amount detection means, corresponding to step S 15 shown in FIG. 2 ) for detecting the limit storage amount of NH 3 that can be stored in the SCR catalyst 13 at that time (limit NH 3 storage amount ST 21 ).
  • the addition-amount controller further includes a control program (steps S 17 , S 171 , and S 172 shown in FIG. 2 ) for setting a variable range of the target NH 3 storage amount ST 2 by using the limit NH 3 storage amount ST 21 .
  • the limit NH 3 storage amount ST 21 is detected by the process at step S 15 and is set as the upper limit value (guard value). Thus, it is possible to set the limit NH 3 storage amount ST 21 as the upper limit, so as to prevent (or suppress) the supply of the excess NH 3 .
  • step S 15 shown in FIG. 2 the limit NH 3 storage amount ST 21 is detected based on the exhaust gas temperature on the downstream side with respect to the catalyst 13 , which corresponds to the temperature of the SCR catalyst 13 . Thus, it can detect (estimate) the temperature of the SCR catalyst 13 with high accuracy.
  • a temperature lower than the catalyst temperature of “140° C.” supposed in idling, and an NH 3 storage amount corresponding to the temperature are set as the critical reaction temperature T 1 , and further as the required NH 3 storage amount ST 22 (see FIG. 6 for both), respectively. This can surely purify the exhaust gas even when starting to accelerate from the idling state.
  • the urea water addition valve 16 is configured to inject and add the urea aqueous solution as the additive for acting as the NH 3 generating source, to the exhaust gas on the upstream side (exhaust pipe 12 ) with respect to the SCR catalyst 13 (that is, to achieve the so-called urea SCR system).
  • the urea aqueous solution is injected and added to the exhaust gas on the upstream side with respect to the SCR catalyst 13 . Therefore, until the urea water reaches the catalyst 13 , the urea is hydrolyzed by exhaust gas heat or the like to form NH 3 . This can supply more NH 3 (purifying agent) to the SCR catalyst 13 .
  • the above urea SCR system is installed on the vehicle equipped with the diesel engine (four-wheeled vehicle in this embodiment). This can improve the fuel efficiency and decrease the PM by allowing the generation of NO x during the combustion process. This can achieve the cleaner diesel vehicle having the high exhaust gas purification capacity.
  • the exhaust emission control system includes the SCR catalyst 13 and the urea water addition valve 16 together with each program (ECU 40 ), and a urea water supply device (the urea water tank 17 a, the pump 17 b, and the like) for supplying the urea aqueous solution to the addition valve 16 .
  • the exhaust emission control system with this arrangement achieves the exhaust gas purification system having the higher exhaust gas purification capacity.
  • the catalyst temperature Tc when the catalyst temperature Tc is in the predetermined temperature range (Tc ⁇ Ts) using the critical reaction temperature (determination value Ts) as the upper limit boundary value, the catalyst temperature To is determined to be lower than the allowable level (step S 13 shown in FIG. 2 ), but the invention is not limited thereto.
  • a predetermined temperature (a temperature lower than the critical reaction temperature of each time only by a predetermined temperature, or a sufficiently low fixed value) lower than the critical reaction temperature may be set as the determination value Ts.
  • the catalyst temperature Tc when the catalyst temperature Tc is in a predetermined temperature range (“Tc ⁇ Ts” or “Tc ⁇ Ts”) using the determination value Ts as the upper limit boundary value, the catalyst temperature Tc may be determined to be lower than the allowable level at step S 13 described above. In such a case, an effect based on the effect described in the paragraph (5) can be obtained.
  • the control process at step S 15 , S 17 , S 171 , or S 172 shown in FIG. 2 may be omitted.
  • the required NH 3 storage amount ST 22 is effectively set to the target NH 3 storage amount ST 2 as it is.
  • the dissatisfaction time period (the non-execution time period of the storage control mode) is set when the rotation speed of the output shaft of the engine (engine rotation speed) is decelerated from the high speed state in which the rotation speed is higher than the allowable level, but the invention is not limited thereto.
  • the dissatisfaction time interval may be set. That is, in this case, for example, at step S 31 , it is determined whether or not the amount of fluctuation in an accelerator operation amount (corresponding to a required torque) toward the negative side (non-operation side) is larger than a predetermined determination value.
  • the amount of fluctuation is the amount of change per unit of time, for example.
  • the amount of fluctuation in the accelerator operation amount is determined to be larger (it is determined that the amount of pushing the accelerator quickly becomes smaller) at step S 31 , the procedure will proceed to step S 32 .
  • an estimated value based on such an accelerator operation amount but also, for example, an actually measured value by a cylinder inner pressure sensor can be used as the detection value of the load on the engine.
  • the dissatisfaction time interval may be set. That is, in this case, for example, it is determined whether or not the amount of fluctuation in the engine rotation speed toward the negative side (deceleration side) is larger than the predetermined determination value.
  • the amount of fluctuation in the engine rotation speed is determined to be larger at step S 31 , the procedure will proceed to step S 32 .
  • the dissatisfaction time period may be set. That is, in this case, for example, at step S 31 , it is determined whether the fuel cut is being performed or not. When it is determined that the fuel cut is being performed at step S 31 , the procedure will proceed to step S 32 .
  • these structures can obtain an effect based on the effect described in the paragraph (1).
  • the addition-amount controller includes a control program (operating mode determination means) for determining whether the operating mode of the engine (internal combustion engine) at that time is a preset operating mode or not.
  • the preset operating mode is a mode in which the load applied to the output shaft of the engine is controlled to be decreased when the temperature of the SCR catalyst 13 is in the high temperature state exceeding the critical reaction temperature (activation temperature). Specifically, it is determined whether the operating mode at that time is the above-mentioned preset operating mode or not at step S 31 shown in FIG. 3 . With this arrangement, when, for example, the operating mode at that time is determined to be the preset operating mode, the procedure will proceed to step S 32 .
  • the addition of urea water by the urea water addition valve 16 (storage control mode) for the purpose of storing NH 3 on the SCR catalyst 13 by the amount corresponding to the addition amount by the valve 16 is prohibited for a predetermined time period (i.e., a time period until the catalyst temperature becomes lower than the allowable level). Also this arrangement can obtain an effect based on the effect described in the paragraph (1). It is effective that the preset operating modes set can include, for example, the deceleration operation, the fuel cut operation, the reduced-cylinder operation, and the like.
  • the dissatisfaction time period set is not limited to the time period associated with the catalyst temperature, but can be any other time period.
  • the dissatisfaction time period may be set based on the time. Specifically, the timing after a predetermined time from the start of the deceleration may be set as the end timing of the dissatisfaction time period.
  • the end timing of the dissatisfaction time period corresponds to the start timing of NH 3 storage.
  • control modes of the purification control mode and the storage control mode are switched, the invention is not limited thereto. Adding another control mode to these control modes enables selection of one to be executed at that time from among three or more types of control modes based on satisfaction of the execution condition of each mode.
  • mode selection may be performed through the processing exemplified as shown in the flowchart of FIG. 9 .
  • the use of a value of a urea water addition control flag F (“0 to 2”) selects one of three types of the purification control mode, the storage control mode, and the urea water non-addition mode.
  • step S 101 it is determined whether or not a predetermined execution condition associated with the storage control mode (storage control execution condition) is satisfied at step S 101 .
  • a predetermined execution condition associated with the storage control mode storage control execution condition
  • the urea water addition control flag F is set to “2” at the subsequent step S 103 .
  • the storage control execution condition is determined not to be satisfied at step S 101 , it is determined whether or not a predetermined execution condition associated with the purification control mode (purification control execution condition) is satisfied in the subsequent step S 102 .
  • the purification control execution condition is determined to be satisfied at step S 102
  • the urea water addition control flag F is set to “1” at the subsequent step S 105 .
  • the purification control execution condition is determined not to be satisfied at step S 102
  • the urea water addition control flag F is set to “0” at the subsequent step S 104 .
  • the NH 3 storage amount is set corresponding to the predetermined critical reaction temperature T 1 lower than the catalyst temperature of “140° C.” supposed in idling, as the required NH 3 storage amount ST 22 for use in determination of the target NH 3 storage amount ST 2 , the invention is not limited thereto.
  • the required NH 3 storage amount ST 22 can be effectively set to a boundary value (convergent point) at which the critical reaction temperature is not decreased even by increasing the NH 3 storage amount of the SCR catalyst 13 . This arrangement can suitably prevent (or suppress) the excess storage of NH 3 not contributing to the critical reaction temperature.
  • the required NH 3 storage amount ST 22 is set as the fixed value, but the invention is not limited thereto.
  • the required NH 3 storage amount ST 22 may be variably set according to the condition of each time.
  • the storage amount may be set to differ between at the startup time of the engine and the idling time.
  • the required NH 3 storage amount ST 22 may be variably set according to a target value of the critical reaction temperature or a target value of the NO x purification ratio on the SCR catalyst 13 .
  • the catalyst temperature Tc is determined based on the exhaust gas temperature.
  • the temperature of the catalyst itself is not determined, and the exhaust gas temperature may be used as a substitute for the catalyst temperature.
  • the NO x amount in the exhaust gas can be determined not only by estimation from the engine operating state, but also, for example, by the actually measured value (sensor output) by an NO x sensor or the like. Furthermore, for example, the NO x amount in the exhaust gas can be estimated based on the state of the exhaust gas (e.g., exhaust gas temperature detected, for example, by the exhaust gas temperature sensor or the like) or components (for example, an oxygen concentration detected by an oxygen concentration sensor or the like).
  • the kind of the exhaust gas generating source to be purified or the system structure can be arbitrarily changed according to the used conditions or the like.
  • the invention when the exhaust gas from the engine for a vehicle is an object to be purified, the invention can be applied not only to a compression ignition diesel engine, but also a spark ignition gasoline engine or the like. Since the compression ignition engine, such as the diesel engine, has the low exhaust gas temperature as compared to that in the spark ignition engine, the invention is effectively applied to the compression ignition engine, thereby enhancing the purification capacity when the catalyst temperature is low.
  • the invention can also be applied to a rotary engine or the like other than a reciprocating engine.
  • the invention can also be applied to purification of exhaust gas from sources other than the vehicle, that is, for example, purification of exhaust gas from an electric power plant, various factories, or the like.
  • the system structure may be changed in the following way.
  • the additive urea water
  • the additive is added to the exhaust gas on the upstream side with respect to the catalyst 13 to deliver the additive to the catalyst 13 by the exhaust gas flow, but the invention is not limited thereto.
  • the additive may be directly added (for example, injected) to the catalyst itself.
  • the NH 3 catalyst 15 can be omitted from the structure.
  • the main demand for the invention comes from the urea-SCR (selective reduction) system.
  • the invention can also be used for other applications as long as the exhaust gas is purified on a catalyst using the same purifying agent (NH 3 ) for purifying the same specific component of interest.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Combustion & Propulsion (AREA)
  • Health & Medical Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Biomedical Technology (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Toxicology (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Exhaust Gas Treatment By Means Of Catalyst (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
US12/146,829 2007-06-27 2008-06-26 Addition-amount controller for exhaust gas purifying agent and exhaust emission control system Abandoned US20090000278A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2007168405A JP4459986B2 (ja) 2007-06-27 2007-06-27 排気浄化剤の添加量制御装置、及び排気浄化システム
JP2007-168405 2007-06-27

Publications (1)

Publication Number Publication Date
US20090000278A1 true US20090000278A1 (en) 2009-01-01

Family

ID=40092660

Family Applications (1)

Application Number Title Priority Date Filing Date
US12/146,829 Abandoned US20090000278A1 (en) 2007-06-27 2008-06-26 Addition-amount controller for exhaust gas purifying agent and exhaust emission control system

Country Status (3)

Country Link
US (1) US20090000278A1 (ja)
JP (1) JP4459986B2 (ja)
DE (1) DE102008002326B4 (ja)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090000280A1 (en) * 2007-06-27 2009-01-01 Denso Corporation Addition-amount controller for exhaust gas purifying agent and exhaust emission control system
US20090000279A1 (en) * 2007-06-27 2009-01-01 Denso Corporation Addition-amount controller for exhaust gas purifying agent and exhaust emission control system
FR2952675A1 (fr) * 2009-11-17 2011-05-20 Peugeot Citroen Automobiles Sa Procede de controle des emissions polluantes d'un moteur a combustion
CN102906410A (zh) * 2010-05-21 2013-01-30 丰田自动车株式会社 内燃机的控制装置
EP2570626A4 (en) * 2010-05-14 2014-03-26 Toyota Motor Co Ltd Exhaust gas purification system for internal combustion engine
US20180320572A1 (en) * 2017-05-04 2018-11-08 GM Global Technology Operations LLC Selective catalytic reduction dosing control
WO2022084850A1 (en) * 2020-10-19 2022-04-28 Fpt Motorenforschung Ag Method and system for managing an active scr device of an aftretreatment system ats
DE112014004254B4 (de) 2013-09-17 2022-04-28 Cummins Emission Solutions Inc. System, Verfahren und Vorrichtung für Niedertemperatur-Dosierung in Diesel-Abgas-Systemen

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6295809B1 (en) * 1999-07-12 2001-10-02 Ford Global Technologies, Inc. Emission control system with a catalyst
US6427439B1 (en) * 2000-07-13 2002-08-06 Ford Global Technologies, Inc. Method and system for NOx reduction
US20030037542A1 (en) * 2001-08-09 2003-02-27 Lifeng Xu High efficiency conversion of nitrogen oxides in an exhaust aftertreatment device at low temperature
US20030182935A1 (en) * 2002-03-29 2003-10-02 Kenji Kawai NOx cleaning apparatus and NOx cleaning method for internal combustion engine
US6637196B1 (en) * 1999-11-24 2003-10-28 Siemens Aktiengesellschaft Device and method for denoxing exhaust gas from an internal combustion engine
US6871489B2 (en) * 2003-04-16 2005-03-29 Arvin Technologies, Inc. Thermal management of exhaust systems
US20050103000A1 (en) * 2003-11-19 2005-05-19 Nieuwstadt Michiel V. Diagnosis of a urea scr catalytic system
US6959540B2 (en) * 1998-06-23 2005-11-01 Toyota Jidosha Kabushiki Kaisha Exhaust gas purification device of internal combustion engine
US20060000202A1 (en) * 2004-06-30 2006-01-05 Wolfgang Ripper Method for operating a catalytic converter used for purifying the exhaust gas of an internal combustion engine and a device for implementing the method
US20060272317A1 (en) * 2005-06-03 2006-12-07 Brown David B Exhaust treatment diagnostic using a temperature sensor
US20070048204A1 (en) * 2005-09-01 2007-03-01 Rahul Mital Flash injector for NH3-SCR NOx aftertreatment
US20070160508A1 (en) * 2005-12-09 2007-07-12 Mitsubishi Fuso Truck And Bus Corporation Exhaust gas purification device
US20090000280A1 (en) * 2007-06-27 2009-01-01 Denso Corporation Addition-amount controller for exhaust gas purifying agent and exhaust emission control system

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003293739A (ja) 2002-04-02 2003-10-15 Mitsubishi Fuso Truck & Bus Corp 内燃機関のＮＯｘ浄化装置

Patent Citations (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7086223B2 (en) * 1998-06-23 2006-08-08 Toyota Jidosha Kabushiki Kaisha Exhaust gas purification device of internal combustion engine
US7272924B2 (en) * 1998-06-23 2007-09-25 Toyota Jidosha Kabushiki Kaisha Exhaust gas purification device of internal combustion engine
US6959540B2 (en) * 1998-06-23 2005-11-01 Toyota Jidosha Kabushiki Kaisha Exhaust gas purification device of internal combustion engine
US20050262832A1 (en) * 1998-06-23 2005-12-01 Kazuhiro Itoh Exhaust gas purification device of internal combustion engine
US7086222B2 (en) * 1998-06-23 2006-08-08 Toyota Jidosha Kabushiki Kaisha Exhaust gas purification device of internal combustion engine
US6295809B1 (en) * 1999-07-12 2001-10-02 Ford Global Technologies, Inc. Emission control system with a catalyst
US6637196B1 (en) * 1999-11-24 2003-10-28 Siemens Aktiengesellschaft Device and method for denoxing exhaust gas from an internal combustion engine
US6427439B1 (en) * 2000-07-13 2002-08-06 Ford Global Technologies, Inc. Method and system for NOx reduction
US20030037542A1 (en) * 2001-08-09 2003-02-27 Lifeng Xu High efficiency conversion of nitrogen oxides in an exhaust aftertreatment device at low temperature
US20050005596A1 (en) * 2001-08-09 2005-01-13 Lifeng Xu High efficiency conversion of nitrogen oxides in an exhaust aftertreatment device at low temperature
US20030182935A1 (en) * 2002-03-29 2003-10-02 Kenji Kawai NOx cleaning apparatus and NOx cleaning method for internal combustion engine
US6871489B2 (en) * 2003-04-16 2005-03-29 Arvin Technologies, Inc. Thermal management of exhaust systems
US20050103000A1 (en) * 2003-11-19 2005-05-19 Nieuwstadt Michiel V. Diagnosis of a urea scr catalytic system
US20060000202A1 (en) * 2004-06-30 2006-01-05 Wolfgang Ripper Method for operating a catalytic converter used for purifying the exhaust gas of an internal combustion engine and a device for implementing the method
US20060272317A1 (en) * 2005-06-03 2006-12-07 Brown David B Exhaust treatment diagnostic using a temperature sensor
US20070048204A1 (en) * 2005-09-01 2007-03-01 Rahul Mital Flash injector for NH3-SCR NOx aftertreatment
US20070160508A1 (en) * 2005-12-09 2007-07-12 Mitsubishi Fuso Truck And Bus Corporation Exhaust gas purification device
US20090000280A1 (en) * 2007-06-27 2009-01-01 Denso Corporation Addition-amount controller for exhaust gas purifying agent and exhaust emission control system

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090000279A1 (en) * 2007-06-27 2009-01-01 Denso Corporation Addition-amount controller for exhaust gas purifying agent and exhaust emission control system
US8336298B2 (en) 2007-06-27 2012-12-25 Denso Corporation Addition-amount controller for exhaust gas purifying agent and exhaust emission control system
US8341940B2 (en) 2007-06-27 2013-01-01 Denso Corporation Addition-amount controller for exhaust gas purifying agent and exhaust emission control system
US20090000280A1 (en) * 2007-06-27 2009-01-01 Denso Corporation Addition-amount controller for exhaust gas purifying agent and exhaust emission control system
FR2952675A1 (fr) * 2009-11-17 2011-05-20 Peugeot Citroen Automobiles Sa Procede de controle des emissions polluantes d'un moteur a combustion
WO2011061425A1 (fr) * 2009-11-17 2011-05-26 Peugeot Citroën Automobiles SA Procede de controle des emissions polluantes d'un moteur a combustion
EP2570626A4 (en) * 2010-05-14 2014-03-26 Toyota Motor Co Ltd Exhaust gas purification system for internal combustion engine
CN102906410A (zh) * 2010-05-21 2013-01-30 丰田自动车株式会社 内燃机的控制装置
DE112014004254B4 (de) 2013-09-17 2022-04-28 Cummins Emission Solutions Inc. System, Verfahren und Vorrichtung für Niedertemperatur-Dosierung in Diesel-Abgas-Systemen
US20180320572A1 (en) * 2017-05-04 2018-11-08 GM Global Technology Operations LLC Selective catalytic reduction dosing control
US10443471B2 (en) * 2017-05-04 2019-10-15 GM Global Technology Operations LLC Selective catalytic reduction dosing control
CN108798840B (zh) * 2017-05-04 2021-01-19 通用汽车环球科技运作有限责任公司 用于处理包括内燃机的机动车辆中的排气的排放控制系统
CN108798840A (zh) * 2017-05-04 2018-11-13 通用汽车环球科技运作有限责任公司 选择性催化还原配量控制
WO2022084850A1 (en) * 2020-10-19 2022-04-28 Fpt Motorenforschung Ag Method and system for managing an active scr device of an aftretreatment system ats
CN116438368A (zh) * 2020-10-19 2023-07-14 Fpt发动机研究公司 用于管理后处理系统ats的活性scr装置的方法和系统
US12098687B2 (en) 2020-10-19 2024-09-24 Fpt Motorenforschung Ag Method and system for managing an active selective catalyst reduction device of an after treatment system

Also Published As

Publication number Publication date
JP4459986B2 (ja) 2010-04-28
JP2009007967A (ja) 2009-01-15
DE102008002326A1 (de) 2009-01-08
DE102008002326B4 (de) 2016-12-29

Similar Documents

Publication Publication Date Title
US8341940B2 (en) Addition-amount controller for exhaust gas purifying agent and exhaust emission control system
US20090000278A1 (en) Addition-amount controller for exhaust gas purifying agent and exhaust emission control system
EP2172627B1 (en) Exhaust emission control device
CN108625953B (zh) 内燃机的排气净化装置
EP1653058A1 (en) Engine exhaust gas cleaning method and system
JP4407705B2 (ja) 排気浄化剤の添加量制御装置、及び排気浄化システム
US8540953B2 (en) Exhaust gas control apparatus and reductant dispensing method for internal combustion engine
JP2010121478A (ja) 内燃機関の排気浄化制御装置及び排気浄化システム
CN101384800A (zh) 内燃机的排气净化装置
US8336298B2 (en) Addition-amount controller for exhaust gas purifying agent and exhaust emission control system
EP2937534B1 (en) System for purifying exhaust of internal combustion engine
JP2005240811A (ja) 内燃機関の排気浄化装置
JP6344259B2 (ja) 尿素添加制御装置、学習装置
EP3025036B1 (en) Scr exhaust emission control system and method therefore, for filling the urea reducing agent after returning to the tank
CN107448264A (zh) 内燃机的排气净化装置
JP2008163856A (ja) 内燃機関の排気浄化装置
US20180179936A1 (en) Exhaust gas purification apparatus for an internal combustion engine
JP2016037903A (ja) 内燃機関の排気浄化装置
JP2015086714A (ja) 内燃機関の排気浄化装置
US20100077736A1 (en) Exhaust purification system for internal combustion engine
JP2011241783A (ja) 内燃機関の排気浄化装置
JP6573225B2 (ja) エンジンの自動停止制御装置
JP2011117458A (ja) 内燃機関の排気浄化装置
JP4779774B2 (ja) 内燃機関の排気浄化装置
JP2018112089A (ja) 還元剤添加弁の異常診断装置

Legal Events

Date Code Title Description
AS Assignment

Owner name: NIPPON SOKEN, INC., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ICHIKAWA, ATARU;NAKAMURA, TUTOMU;SHIMOMURA, OSAMU;REEL/FRAME:021155/0399;SIGNING DATES FROM 20080526 TO 20080529

Owner name: DENSO CORPORATION, JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ICHIKAWA, ATARU;NAKAMURA, TUTOMU;SHIMOMURA, OSAMU;REEL/FRAME:021155/0399;SIGNING DATES FROM 20080526 TO 20080529

STCB Information on status: application discontinuation

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