US20080034732A1 - Exhaust Emission Control Device - Google Patents

Exhaust Emission Control Device Download PDF

Info

Publication number
US20080034732A1
US20080034732A1 US11/569,688 US56968805A US2008034732A1 US 20080034732 A1 US20080034732 A1 US 20080034732A1 US 56968805 A US56968805 A US 56968805A US 2008034732 A1 US2008034732 A1 US 2008034732A1
Authority
US
United States
Prior art keywords
control device
selective reduction
reduction catalyst
urea water
reducing agent
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
US11/569,688
Inventor
Mitsuru Hosoya
Masatoshi Shimoda
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.)
Hino Motors Ltd
Original Assignee
Individual
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 Individual filed Critical Individual
Publication of US20080034732A1 publication Critical patent/US20080034732A1/en
Assigned to HINO MOTORS, LTD. reassignment HINO MOTORS, LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: HOSOYA, MITSURU, SHIMODA, MASATOSHI
Abandoned legal-status Critical Current

Links

Images

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D41/00Electrical control of supply of combustible mixture or its constituents
    • F02D41/02Circuit arrangements for generating control signals
    • F02D41/14Introducing closed-loop corrections
    • F02D41/1438Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
    • F02D41/1444Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
    • F02D41/146Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being an NOx content or concentration
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation 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
    • B01D53/34Chemical or biological purification of waste gases
    • B01D53/92Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9404Removing only nitrogen compounds
    • B01D53/9409Nitrogen oxides
    • B01D53/9431Processes characterised by a specific device
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N11/00Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
    • F01N11/007Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity the diagnostic devices measuring oxygen or air concentration downstream of the exhaust apparatus
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10Exhaust 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
    • F01N3/18Exhaust 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
    • F01N3/20Exhaust 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
    • F01N3/2066Selective catalytic reduction [SCR]
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D41/00Electrical control of supply of combustible mixture or its constituents
    • F02D41/22Safety or indicating devices for abnormal conditions
    • F02D41/221Safety or indicating devices for abnormal conditions relating to the failure of actuators or electrically driven elements
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2550/00Monitoring or diagnosing the deterioration of exhaust systems
    • F01N2550/05Systems for adding substances into exhaust
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2560/00Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/02Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor
    • F01N2560/026Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor for measuring or detecting NOx
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01NGAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2610/00Adding substances to exhaust gases
    • F01N2610/02Adding substances to exhaust gases the substance being ammonia or urea
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D41/00Electrical control of supply of combustible mixture or its constituents
    • F02D41/02Circuit arrangements for generating control signals
    • F02D41/021Introducing corrections for particular conditions exterior to the engine
    • F02D41/0235Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
    • F02D41/027Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus
    • F02D41/0275Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus the exhaust gas treating apparatus being a NOx trap or adsorbent
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00Road transport of goods or passengers
    • Y02T10/10Internal combustion engine [ICE] based vehicles
    • Y02T10/12Improving ICE efficiencies
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00Road transport of goods or passengers
    • Y02T10/10Internal combustion engine [ICE] based vehicles
    • Y02T10/40Engine management systems

Definitions

  • the present invention relates to an exhaust emission control device wherein NO x in exhaust gas is depurated through reduction.
  • some diesel engines have been provided with selective reduction catalyst incorporated in an exhaust pipe through which exhaust gas flows, said catalyst having a characteristic of selectively reacting NO x with a reducing agent even in the presence of oxygen.
  • a required amount of reducing agent is added upstream of the selective reduction catalyst to reduce NO x (nitrogen oxides) in the exhaust gas with the reducing agent on the catalyst to thereby reduce a concentration of discharged NO x .
  • urea water when added to the exhaust gas upstream of the selective reduction catalyst, the urea water is decomposed into ammonia and carbon dioxide gas with the temperature condition of about 170-180° C. or more to thereby depurate well NO x in the exhaust gas through reduction by ammonia on the catalyst.
  • the invention was made in view of the above and has its object to minimize the increase of NO x emission even if the NO x deputation system has malfunction.
  • the invention is directed to an exhaust emission control device wherein selective reduction catalyst is incorporated in an exhaust pipe, a reducing agent being added upstream of said catalyst by reducing-agent adding means to depurate NO x through reduction, comprising NO x sensors arranged respectively on entry and exit sides of the selective reduction catalyst for detecting NO x concentrations, and a control device for judging abnormality on the basis of detection signals from both of the NO x sensors by non-attainment of a predetermined NO x reduction ratio and for commanding restriction of an amount of fuel to be injected when said abnormality is judged.
  • No x concentrations on the entry and exit sides of the selective reduction catalyst are monitored by the control device on the basis of the detection signals from both of the NO x sensors, and abnormality of not attaining the predetermined NO x reduction ratio is judged when no remarkable difference is ascertained between the NO x concentrations on the entry and exit sides of the selective reduction catalyst; when such abnormality is judged, the amount of fuel to be injected is restricted by the command from the control device, so that an amount of NO x to be generated in the engine is reduced to suppress the increase of NO x emission.
  • the reducing agent may be urea water and the selective reduction catalyst may have a characteristic of capable of selectively reacting NO x with ammonia even in the presence of oxygen.
  • an excellent effect or advantage is obtained: even when an NO x deputation system has malfunction, the amount of fuel to be injected can be restricted to reduce an amount of NO x to be generated in the engine, whereby increase of NO x emission can be minimized.
  • FIG. 1 A schematic view showing an embodiment of the invention.
  • FIG. 2 A perspective view showing partly in cutout the selective reduction catalyst of FIG. 1 .
  • FIG. 3 A flow chart showing control steps of the NO x depuration control device shown in FIG. 1 .
  • FIGS. 1-3 shows the embodiment of the invention.
  • reference numeral 1 denotes diesel engine.
  • the engine 1 shown has a turbocharger 2 with a compressor 2 a to which air 4 from an air cleaner 3 is fed via an intake pipe 5 .
  • the air 4 thus pressurized in the compressor 2 a is fed further through the intake pipe to an intercooler 6 for cooling.
  • the cooled air 4 from the intercooler 6 is fed to an intake manifold (not shown) where the air 4 is introduced to each cylinder of the engine 1 .
  • the exhaust gas 7 discharged from each cylinder of the engine 1 is fed via an exhaust manifold 8 to a turbine 2 b of the turbocharger 2 , the exhaust gas 7 after having driven the turbine 2 b being discharged outside via an exhaust pipe 9 .
  • Selective reduction catalyst 10 encased in a casing 11 is incorporated in the exhaust pipe 9 through which exhaust gas 7 flows.
  • the selective reduction catalyst 10 is formed as flow-through type honeycomb structure as shown in FIG. 2 , and has a characteristic of capable of selectively reacting NO x with ammonia even in the presence of oxygen.
  • urea-water injection valve 13 with an injection nozzle 12 , the injection valve 13 being connected to an urea water tank 14 arranged at an appropriate site via an urea-water supply line 15 , so that the urea water (reducing agent) 17 in the tank 14 can be added upstream of the selective reduction catalyst 10 via the injection valve 13 by driving a supply pump 16 incorporated in the supply line 15 .
  • urea-water adding means (reducing-agent adding means) 18 is constituted by the urea-water injection valve 13 , urea water tank 14 , urea-water supply line 15 and supply pump 16 .
  • the engine 1 is provided with a revolution sensor 19 for detecting revolution of the engine.
  • a revolution signal 19 a from the revolution sensor 19 and a load signal 20 a from an accelerator sensor 20 (sensor for detecting treadled angle of an accelerator pedal) are inputted into an engine control unit or electric control unit 21 (ECU).
  • a fuel injection signal 22 a for commanding fuel injection timing and amount to be injected is outputted to a fuel injection device 22 for injecting fuel to each cylinder of the engine 1 , so that appropriate fuel injection control is carried out on the basis of current operation status judged from the above-mentioned revolution and load signals 19 a and 20 a from the sensors 19 and 20 .
  • the fuel injection device 22 comprises a plurality of injectors (not shown) each for each cylinder, an electromagnetic valve in each of the injectors being controlled in its opening by the fuel injection signal 22 a so as to appropriately control the fuel injection timing and amount to be injected.
  • An NO x deputation control device 23 (control device) arranged separately from the ECU 21 outputs a valve-opening command signal 13 a to the urea-water injection valve 13 , and further outputs a drive command signal 16 a to the supply pump 16 .
  • a valve-opening command signal 13 a to the urea-water injection valve 13
  • a drive command signal 16 a to the supply pump 16 .
  • the NO x depuration control device 23 receives from the ECU 21 the revolution and load signals 19 a and 20 a from the sensors 19 and 20 and, on the basis of current operation status judged from these signals, NO x generation amount is estimated; an amount of urea water 17 to be added commensurate with the estimated NO x generation amount is calculated and addition of such required amount of urea water 17 is carried out.
  • Inputted to the NO x deputation control device 23 are detection signals 24 a and 25 a from NO x sensors 24 and 25 arranged respectively on the entry and exit sides of the selective reduction catalyst 10 for detecting NO x concentrations as well as a detection signal 26 a from a temperature sensor 26 arranged on the entry side of the catalyst 10 ; on the basis of these detection signals 24 a , 25 a and 26 a , abnormality where a predetermined temperature or more is attained and a predetermined No x reduction ratio is not attained is judged and, when such abnormality is judged, the control device outputs a control signal 21 a to the ECU 21 so as to command restriction of an amount of fuel to be injected.
  • the revolution signal 19 a from the revolution sensor 19 is ascertained in step S 1 ; the detection signal 26 a from the temperature sensor 26 is ascertained in step S 2 ; and the detections signals 24 a and 25 a from both of the NO x sensors 24 and 25 , respectively, are ascetained in step S 3 .
  • step S 4 determines whether the procedure advances to step S 4 where whether the ratio of the exit-side NO x concentration to the entry-side NO x concentration is less than 0.5 or not is judged; if affirmative or “YES”, the procedure proceeds to step S 5 where restriction of an amount of fuel to be injected is commanded as control signal 21 a to the ECU 21 ; and if negative or “NO”, the procedure returns to step S 1 and the same control sequence is repeated.
  • ascertainment of temperature at step S 2 may not always be carried out by actual measurement through the temperature sensor 26 arranged on the entry side of the selective reduction catalyst 10 .
  • the exhaust temperature may be estimated from the operation status on the basis of the sensed engine revolution and load.
  • the ECU 21 When the ECU 21 receives the control signal 21 a from the NO x deputation control device 23 , it selects a map for fuel injection control with the fuel injection amount being reduced than normal, so that on the basis of this map, a reduced amount of fuel to be injected than usaul is outputted as fuel injection signal 22 a to the fuel injection device 22 .
  • restriction of the fuel injection amount lower than usual must be accompanied by changes of injection timing and pressure to appropriate values (corresponding to the change of the fuel injection amount). Therefore these are also adapted to be changed accordingly.
  • NO x concentrations on the entry and exit sides of the selective reduction catalyst 10 are monitored by NO x deputation control device 23 on the basis of the detection signals 24 a and 25 a from both of the NO x sensors 24 and 25 : when no remarkable difference between those on the entry and exit sides of the selective reduction catalyst 10 is ascertained, abnormality as non-attainment of a predetermined No x reduction ratio is judged, and when such abnormality is judged, the control signal 21 a is outputted from the NO x depuration control device 23 to the ECU 21 so as to restrict the amount of fuel to be injected; as a result, an amount of NO x to be generated in the engine 1 is reduced to suppress the increase of NO x emission.
  • an amount of fuel to be injected can be restricted to reduce an amount of NO x to be generated in the engine 1 to thereby minimize increase of NO x emission.
  • an exhaust emission control device of the invention is not limited to the above-mentioned embodiment and that various changes and modifications may be effected without leaving the gist of the invention.
  • the reducing agent added to the selective reduction catalyst may be diesel oil or the like other than the urea water.

Abstract

Increase of NOx emission is minimized even under a condition that NOx depuration system has malfunction.
An exhaust emission control device is disclosed which has selective reduction catalyst 10 incorporated in an exhaust pipe 9, urea water 17 (reducing agent) being added to exhaust gas upstream of the selective reduction catalyst 10 by urea water adding means 18 (reducing agent adding means) so as to depurate NOx through reduction. The exhaust emission control device has NOx sensors 24 and 25 respectively arranged on entry and exit sides of the selective reduction catalyst 10 for detecting NOx concentrations, and an NOx deputation control device 23 (control device) which judges abnormality, on the basis of detection signals 24a and 25a from the NOx sensors 24 and 25, by non-attainment of a predetermined Nox reduction ratio and, when such abnormality is judged, restriction of an amount of fuel to be injected is commanded.

Description

    TECHNICAL FIELD
  • The present invention relates to an exhaust emission control device wherein NOx in exhaust gas is depurated through reduction.
  • BACKGROUND ART
  • Conventionally, some diesel engines have been provided with selective reduction catalyst incorporated in an exhaust pipe through which exhaust gas flows, said catalyst having a characteristic of selectively reacting NOx with a reducing agent even in the presence of oxygen. A required amount of reducing agent is added upstream of the selective reduction catalyst to reduce NOx (nitrogen oxides) in the exhaust gas with the reducing agent on the catalyst to thereby reduce a concentration of discharged NOx.
  • In a field of industrial plant or the like with flue-gas denitration, it has been well known that ammonia (NH3) is effectively used as reducing agent to depurate NOx through reduction. However, for automobiles, safety in carrying ammonia itself during running is difficult to ensure, so that in recent years, use of nontoxic urea water as reducing agent has been researched (see, for example, Reference 1).
  • [Reference 1] JP 2002-161732A
  • More specifically when urea water is added to the exhaust gas upstream of the selective reduction catalyst, the urea water is decomposed into ammonia and carbon dioxide gas with the temperature condition of about 170-180° C. or more to thereby depurate well NOx in the exhaust gas through reduction by ammonia on the catalyst.
  • SUMMARY OF THE INVENTION Problems to be Solved by the Invention
  • However, in this kind of selective reduction catalyst, there may be a fear that urea water is left unreplenished or that urea water is not replenished in an appropriate concentration. In such a case, there may be a fear that, even if appropriate addition of urea water is commanded by a control system, system malfunction of not attaining targeted Nox reduction ratio may occur, resulting in increase of NOx emission before such system malfunction is resolved.
  • The invention was made in view of the above and has its object to minimize the increase of NOx emission even if the NOx deputation system has malfunction.
  • Means or Measures for Solving the Problems
  • The invention is directed to an exhaust emission control device wherein selective reduction catalyst is incorporated in an exhaust pipe, a reducing agent being added upstream of said catalyst by reducing-agent adding means to depurate NOx through reduction, comprising NOx sensors arranged respectively on entry and exit sides of the selective reduction catalyst for detecting NOx concentrations, and a control device for judging abnormality on the basis of detection signals from both of the NOx sensors by non-attainment of a predetermined NOx reduction ratio and for commanding restriction of an amount of fuel to be injected when said abnormality is judged.
  • More specifically, Nox concentrations on the entry and exit sides of the selective reduction catalyst are monitored by the control device on the basis of the detection signals from both of the NOx sensors, and abnormality of not attaining the predetermined NOx reduction ratio is judged when no remarkable difference is ascertained between the NOx concentrations on the entry and exit sides of the selective reduction catalyst; when such abnormality is judged, the amount of fuel to be injected is restricted by the command from the control device, so that an amount of NOx to be generated in the engine is reduced to suppress the increase of NOx emission.
  • When the invention is worked out more specifically, the reducing agent may be urea water and the selective reduction catalyst may have a characteristic of capable of selectively reacting NOx with ammonia even in the presence of oxygen.
  • Effects of the Invention
  • According to an exhaust emission control device of the invention as mentioned above, an excellent effect or advantage is obtained: even when an NOx deputation system has malfunction, the amount of fuel to be injected can be restricted to reduce an amount of NOx to be generated in the engine, whereby increase of NOx emission can be minimized.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • [FIG. 1] A schematic view showing an embodiment of the invention.
  • [FIG. 2] A perspective view showing partly in cutout the selective reduction catalyst of FIG. 1.
  • [FIG. 3] A flow chart showing control steps of the NOx depuration control device shown in FIG. 1.
  • EXPLANATION OF THE REFERENCE NUMERALS
    • 1 engine
    • 7 exhaust gas
    • 9 exhaust pipe
    • 10 selective reduction catalyst
    • 17 urea water (reducing agent)
    • 18 urea water adding means (reducing-agent adding means)
    • 21 electronic control unit
    • 21 a control signal
    • 22 fuel injection device
    • 23 NOx depuration control device (control device)
    • 24 NOx sensor
    • 24 a detection signal
    • 25 NOx sensor
    • 25 a detection signal
    Best Mode for Carrying Out the Invention
  • Next, an embodiment of the invention will be described in conjunction with the drawings.
  • FIGS. 1-3 shows the embodiment of the invention. In FIG. 1, reference numeral 1 denotes diesel engine. The engine 1 shown has a turbocharger 2 with a compressor 2 a to which air 4 from an air cleaner 3 is fed via an intake pipe 5. The air 4 thus pressurized in the compressor 2 a is fed further through the intake pipe to an intercooler 6 for cooling. The cooled air 4 from the intercooler 6 is fed to an intake manifold (not shown) where the air 4 is introduced to each cylinder of the engine 1.
  • The exhaust gas 7 discharged from each cylinder of the engine 1 is fed via an exhaust manifold 8 to a turbine 2 b of the turbocharger 2, the exhaust gas 7 after having driven the turbine 2 b being discharged outside via an exhaust pipe 9.
  • Selective reduction catalyst 10 encased in a casing 11 is incorporated in the exhaust pipe 9 through which exhaust gas 7 flows. The selective reduction catalyst 10 is formed as flow-through type honeycomb structure as shown in FIG. 2, and has a characteristic of capable of selectively reacting NOx with ammonia even in the presence of oxygen.
  • Further, arranged upstream of the casing 11 is an urea-water injection valve 13 with an injection nozzle 12, the injection valve 13 being connected to an urea water tank 14 arranged at an appropriate site via an urea-water supply line 15, so that the urea water (reducing agent) 17 in the tank 14 can be added upstream of the selective reduction catalyst 10 via the injection valve 13 by driving a supply pump 16 incorporated in the supply line 15. Thus, urea-water adding means (reducing-agent adding means) 18 is constituted by the urea-water injection valve 13, urea water tank 14, urea-water supply line 15 and supply pump 16.
  • The engine 1 is provided with a revolution sensor 19 for detecting revolution of the engine. A revolution signal 19 a from the revolution sensor 19 and a load signal 20 a from an accelerator sensor 20 (sensor for detecting treadled angle of an accelerator pedal) are inputted into an engine control unit or electric control unit 21 (ECU).
  • In the ECU 21, a fuel injection signal 22 a for commanding fuel injection timing and amount to be injected is outputted to a fuel injection device 22 for injecting fuel to each cylinder of the engine 1, so that appropriate fuel injection control is carried out on the basis of current operation status judged from the above-mentioned revolution and load signals 19 a and 20 a from the sensors 19 and 20.
  • More specifically, the fuel injection device 22 comprises a plurality of injectors (not shown) each for each cylinder, an electromagnetic valve in each of the injectors being controlled in its opening by the fuel injection signal 22 a so as to appropriately control the fuel injection timing and amount to be injected.
  • An NOx deputation control device 23 (control device) arranged separately from the ECU 21 outputs a valve-opening command signal 13 a to the urea-water injection valve 13, and further outputs a drive command signal 16 a to the supply pump 16. Thus, by valve-opening actuation of the injection valve 13, the amount of the urea water 17 to be added is appropriately controlled and, upon such addition of the urea water any required injection pressure is obtained by driving the supply pump 16.
  • The NOx depuration control device 23 receives from the ECU 21 the revolution and load signals 19 a and 20 a from the sensors 19 and 20 and, on the basis of current operation status judged from these signals, NOx generation amount is estimated; an amount of urea water 17 to be added commensurate with the estimated NOx generation amount is calculated and addition of such required amount of urea water 17 is carried out.
  • Inputted to the NOx deputation control device 23 are detection signals 24 a and 25 a from NOx sensors 24 and 25 arranged respectively on the entry and exit sides of the selective reduction catalyst 10 for detecting NOx concentrations as well as a detection signal 26 a from a temperature sensor 26 arranged on the entry side of the catalyst 10; on the basis of these detection signals 24 a, 25 a and 26 a, abnormality where a predetermined temperature or more is attained and a predetermined Nox reduction ratio is not attained is judged and, when such abnormality is judged, the control device outputs a control signal 21 a to the ECU 21 so as to command restriction of an amount of fuel to be injected.
  • More specifically, as shown in FIG. 3 which shows specific control sequence in the NOx deputation control device 23, the revolution signal 19 a from the revolution sensor 19 is ascertained in step S1; the detection signal 26 a from the temperature sensor 26 is ascertained in step S2; and the detections signals 24 a and 25 a from both of the NOx sensors 24 and 25, respectively, are ascetained in step S3. Under the operation status that 50% or more of Nox reduction ratio is surely obtained provided that the NOx deputation system has no malfunction, whether the procedure advances to step S4 where whether the ratio of the exit-side NOx concentration to the entry-side NOx concentration is less than 0.5 or not is judged; if affirmative or “YES”, the procedure proceeds to step S5 where restriction of an amount of fuel to be injected is commanded as control signal 21 a to the ECU 21; and if negative or “NO”, the procedure returns to step S1 and the same control sequence is repeated.
  • In this respect, ascertainment of temperature at step S2 may not always be carried out by actual measurement through the temperature sensor 26 arranged on the entry side of the selective reduction catalyst 10. For example, the exhaust temperature may be estimated from the operation status on the basis of the sensed engine revolution and load.
  • When the ECU 21 receives the control signal 21 a from the NOx deputation control device 23, it selects a map for fuel injection control with the fuel injection amount being reduced than normal, so that on the basis of this map, a reduced amount of fuel to be injected than usaul is outputted as fuel injection signal 22 a to the fuel injection device 22.
  • In this case, restriction of the fuel injection amount lower than usual must be accompanied by changes of injection timing and pressure to appropriate values (corresponding to the change of the fuel injection amount). Therefore these are also adapted to be changed accordingly.
  • With the exhaust emission control device thus constructed, NOx concentrations on the entry and exit sides of the selective reduction catalyst 10 are monitored by NOx deputation control device 23 on the basis of the detection signals 24 a and 25 a from both of the NOx sensors 24 and 25: when no remarkable difference between those on the entry and exit sides of the selective reduction catalyst 10 is ascertained, abnormality as non-attainment of a predetermined Nox reduction ratio is judged, and when such abnormality is judged, the control signal 21 a is outputted from the NOx depuration control device 23 to the ECU 21 so as to restrict the amount of fuel to be injected; as a result, an amount of NOx to be generated in the engine 1 is reduced to suppress the increase of NOx emission.
  • Thus, according to the above-mentioned embodiment, even if the NOx deputation system has malfunction, an amount of fuel to be injected can be restricted to reduce an amount of NOx to be generated in the engine 1 to thereby minimize increase of NOx emission.
  • It is to be understood that an exhaust emission control device of the invention is not limited to the above-mentioned embodiment and that various changes and modifications may be effected without leaving the gist of the invention. For example, the reducing agent added to the selective reduction catalyst may be diesel oil or the like other than the urea water.

Claims (2)

1. An exhaust emission control device wherein selective reduction catalyst is incorporated in an exhaust pipe, a reducing agent being added upstream of said catalyst by reducing-agent adding means to depurate NOx through reduction, comprising NOx sensors arranged respectively on entry and exit sides of the selective reduction catalyst for detecting NOx concentrations, and a control device for judging abnormality on the basis of detection signals from both of the NOx sensors by non-attainment of a predetermined NOx reduction ratio and for commanding restriction of an amount of fuel to be injected when said abnormality is judged.
2. An exhaust emission control device as claimed in claim 1, wherein the reducing agent is urea water, the selective reduction catalyst having a characteristic of capable of selectively reacting NOx with ammonia even in the presence of oxygen.
US11/569,688 2004-06-17 2005-06-16 Exhaust Emission Control Device Abandoned US20080034732A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2004179734A JP2006002663A (en) 2004-06-17 2004-06-17 Exhaust emission control device
JP2004-179734 2004-06-17
PCT/JP2005/011022 WO2005124116A1 (en) 2004-06-17 2005-06-16 Exhaust gas purification apparatus

Publications (1)

Publication Number Publication Date
US20080034732A1 true US20080034732A1 (en) 2008-02-14

Family

ID=35509736

Family Applications (1)

Application Number Title Priority Date Filing Date
US11/569,688 Abandoned US20080034732A1 (en) 2004-06-17 2005-06-16 Exhaust Emission Control Device

Country Status (4)

Country Link
US (1) US20080034732A1 (en)
EP (1) EP1767754A4 (en)
JP (1) JP2006002663A (en)
WO (1) WO2005124116A1 (en)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090013666A1 (en) * 2007-07-09 2009-01-15 Jae Yoon Jung Method for determining malfunction of nitrogen oxide sensor and selective catalytic reduction system operating the same
US20100031641A1 (en) * 2007-12-27 2010-02-11 Toyota Jidosha Kabushiki Kaisha Exhaust purification device of an internal combustion engine
US20100139249A1 (en) * 2007-02-21 2010-06-10 Volvo Lastvagnar Ab Exhaust gas after treatment system
CN101845982A (en) * 2009-03-02 2010-09-29 通用汽车环球科技运作公司 Select the NO of catalyst reduction system XThe diagnosis based on model of sensor fault
US20100257844A1 (en) * 2009-04-14 2010-10-14 Denso Corporation Exhaust gas purifying device for internal combustion engine
US20110005223A1 (en) * 2008-03-03 2011-01-13 Yanmar Co., Ltd. Engine
US20110146235A1 (en) * 2007-12-06 2011-06-23 Toyota Jidosha Kabushiki Kaisha Abnormality detection system and abnormality detection method for internal combustion engine
CN102216579A (en) * 2009-01-19 2011-10-12 丰田自动车株式会社 Abnormality detection device for exhaust purification device and abnormality detection method for exhaust purification device
US8132402B2 (en) 2007-04-25 2012-03-13 Toyota Jidosha Kabushiki Kaisha Exhaust purification device of internal combustion engine

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4326976B2 (en) * 2003-10-22 2009-09-09 日産ディーゼル工業株式会社 Engine exhaust purification system
ATE512300T1 (en) 2006-07-12 2011-06-15 Delphi Tech Holding Sarl DOSING PUMP FOR A REDUCING AGENT
JP4687709B2 (en) * 2007-04-25 2011-05-25 トヨタ自動車株式会社 Exhaust gas purification device for internal combustion engine
JP4840703B2 (en) * 2007-11-16 2011-12-21 トヨタ自動車株式会社 Abnormality diagnosis device for exhaust purification system
JP5106248B2 (en) * 2008-05-26 2012-12-26 Udトラックス株式会社 NOx sensor abnormality determination device
JP2013050083A (en) * 2011-08-31 2013-03-14 Mitsubishi Heavy Ind Ltd Operation control method for diesel engine and operation control device for diesel engine
JP5641258B2 (en) * 2012-05-17 2014-12-17 トヨタ自動車株式会社 Exhaust gas purification device for internal combustion engine
US20170203748A1 (en) * 2016-01-20 2017-07-20 Komatsu Ltd. Control device for hybrid work machine, hybrid work machine, and control method for hybrid work machine

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5845487A (en) * 1996-07-19 1998-12-08 Daimler-Benz Ag Method and device for operating an internal combustion engine with low nitrogen oxide emissions
US5937638A (en) * 1996-11-19 1999-08-17 Honda Giken Kogyo Kabushiki Kaisha Method of judging deterioration of catalytic converter for purifying exhaust gas
US6427439B1 (en) * 2000-07-13 2002-08-06 Ford Global Technologies, Inc. Method and system for NOx reduction
US20030051468A1 (en) * 2001-09-04 2003-03-20 Van Nieuwstadt Michiel J. Method and apparatus for determining whether a sensor which is responsive to both a reactant and a substance to be reduced by such reactant is responding to either un-reacted portions of the substance or un-reacted portions of the reactant
US6698191B2 (en) * 2001-08-09 2004-03-02 Ford Global Technologies, Llc High efficiency conversion of nitrogen oxides in an exhaust aftertreatment device at low temperature
US20040040284A1 (en) * 2002-09-04 2004-03-04 Ford Global Technologies, Inc. Exhaust emission diagnostics
US20040098974A1 (en) * 2002-11-21 2004-05-27 Nieuwstadt Michiel J. Van Exhaust gas aftertreatment systems
US6755014B2 (en) * 2002-03-29 2004-06-29 Mitsubishi Fuso Truck And Bus Corporation NOx cleaning apparatus and NOx cleaning method for internal combustion engine
US6892530B2 (en) * 2002-11-21 2005-05-17 Ford Global Technologies, Llc Exhaust gas aftertreatment systems

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2501616Y2 (en) * 1990-11-20 1996-06-19 三菱自動車工業株式会社 Exhaust gas treatment device
JP3114414B2 (en) * 1993-03-12 2000-12-04 日産自動車株式会社 Air-fuel ratio control device for internal combustion engine
JP2985638B2 (en) * 1993-10-18 1999-12-06 トヨタ自動車株式会社 Exhaust gas purification device for internal combustion engine
JP3324557B2 (en) * 1999-04-23 2002-09-17 三菱自動車工業株式会社 Combustion control device for internal combustion engine
JP2003293739A (en) * 2002-04-02 2003-10-15 Mitsubishi Fuso Truck & Bus Corp NOx CLEANING DEVICE FOR INTERNAL COMBUSTION ENGINE
JP4114425B2 (en) * 2002-07-29 2008-07-09 三菱ふそうトラック・バス株式会社 Engine control device
DE10254843A1 (en) * 2002-11-25 2004-06-03 Robert Bosch Gmbh Method of monitoring motor vehicle exhaust gas cleaning system involves injecting urea-water mix into exhaust to determine if sensor output varies

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5845487A (en) * 1996-07-19 1998-12-08 Daimler-Benz Ag Method and device for operating an internal combustion engine with low nitrogen oxide emissions
US5937638A (en) * 1996-11-19 1999-08-17 Honda Giken Kogyo Kabushiki Kaisha Method of judging deterioration of catalytic converter for purifying exhaust gas
US6427439B1 (en) * 2000-07-13 2002-08-06 Ford Global Technologies, Inc. Method and system for NOx reduction
US6698191B2 (en) * 2001-08-09 2004-03-02 Ford Global Technologies, Llc High efficiency conversion of nitrogen oxides in an exhaust aftertreatment device at low temperature
US20030051468A1 (en) * 2001-09-04 2003-03-20 Van Nieuwstadt Michiel J. Method and apparatus for determining whether a sensor which is responsive to both a reactant and a substance to be reduced by such reactant is responding to either un-reacted portions of the substance or un-reacted portions of the reactant
US6546720B2 (en) * 2001-09-04 2003-04-15 Ford Global Technologies, Inc. Method and apparatus for controlling the amount of reactant to be added to a substance using a sensor which is responsive to both the reactant and the substance
US6755014B2 (en) * 2002-03-29 2004-06-29 Mitsubishi Fuso Truck And Bus Corporation NOx cleaning apparatus and NOx cleaning method for internal combustion engine
US20040040284A1 (en) * 2002-09-04 2004-03-04 Ford Global Technologies, Inc. Exhaust emission diagnostics
US6701707B1 (en) * 2002-09-04 2004-03-09 Ford Global Technologies, Llc Exhaust emission diagnostics
US20040098974A1 (en) * 2002-11-21 2004-05-27 Nieuwstadt Michiel J. Van Exhaust gas aftertreatment systems
US6892530B2 (en) * 2002-11-21 2005-05-17 Ford Global Technologies, Llc Exhaust gas aftertreatment systems

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8656702B2 (en) * 2007-02-21 2014-02-25 Volvo Lastvagnar Ab Exhaust gas after treatment system
US20100139249A1 (en) * 2007-02-21 2010-06-10 Volvo Lastvagnar Ab Exhaust gas after treatment system
US8132402B2 (en) 2007-04-25 2012-03-13 Toyota Jidosha Kabushiki Kaisha Exhaust purification device of internal combustion engine
US20090013666A1 (en) * 2007-07-09 2009-01-15 Jae Yoon Jung Method for determining malfunction of nitrogen oxide sensor and selective catalytic reduction system operating the same
US7987661B2 (en) * 2007-07-09 2011-08-02 Hyundai Motor Company Method for determining malfunction of nitrogen oxide sensor and selective catalytic reduction system operating the same
US20110146235A1 (en) * 2007-12-06 2011-06-23 Toyota Jidosha Kabushiki Kaisha Abnormality detection system and abnormality detection method for internal combustion engine
US8171723B2 (en) 2007-12-06 2012-05-08 Toyota Jidosha Kabushiki Kaisha Abnormality detection system and abnormality detection method for internal combustion engine
US8505283B2 (en) 2007-12-27 2013-08-13 Toyota Jidosha Kabushiki Kaisha Exhaust purification device of an internal combustion engine
US20100031641A1 (en) * 2007-12-27 2010-02-11 Toyota Jidosha Kabushiki Kaisha Exhaust purification device of an internal combustion engine
US20110005223A1 (en) * 2008-03-03 2011-01-13 Yanmar Co., Ltd. Engine
US9488124B2 (en) * 2008-03-03 2016-11-08 Yanmar Co., Ltd. Turbocharged engine with post fuel injection control
CN102216579A (en) * 2009-01-19 2011-10-12 丰田自动车株式会社 Abnormality detection device for exhaust purification device and abnormality detection method for exhaust purification device
CN101845982A (en) * 2009-03-02 2010-09-29 通用汽车环球科技运作公司 Select the NO of catalyst reduction system XThe diagnosis based on model of sensor fault
US20100257844A1 (en) * 2009-04-14 2010-10-14 Denso Corporation Exhaust gas purifying device for internal combustion engine
US8418438B2 (en) 2009-04-14 2013-04-16 Denso Corporation Exhaust gas purifying device for internal combustion engine

Also Published As

Publication number Publication date
JP2006002663A (en) 2006-01-05
WO2005124116A1 (en) 2005-12-29
EP1767754A1 (en) 2007-03-28
EP1767754A4 (en) 2008-09-17

Similar Documents

Publication Publication Date Title
US20080034732A1 (en) Exhaust Emission Control Device
US8250859B2 (en) Exhaust emission control device
US7617672B2 (en) Engine exhaust emission control device and exhaust emission control method
US8516808B2 (en) Exhaust purification device of internal combustion engine
US7892508B2 (en) Internal combustion engine exhaust gas purification apparatus and method for controlling same
EP2136046B1 (en) Device for judging deterioration of catalyst
EP1111211B1 (en) Exhaust gas purification system for a lean burn engine
EP2060756B1 (en) Method and system using a reduction catalyst to reduce nitrate oxide
US7842267B2 (en) Exhaust emission purifying apparatus for engine
CN102312712B (en) System and method for determining an age of and controlling a selective catalytic reduction catalyst
CN103422950A (en) Exhaust air injection
US8652410B2 (en) Control method and arrangement for selective catalytic reduction
CN103423002A (en) Exhaust air injection
US8359830B2 (en) Exhaust purification device of an internal combustion engine
EP2426330B1 (en) Method for detecting abnormality in reducing agent
JP2004060515A (en) Engine control device
US20110271663A1 (en) Exhaust purifying device for internal combustion engines
US10125647B2 (en) Exhaust gas purification apparatus for an internal combustion engine
EP2857647B1 (en) Exhaust gas purification apparatus for an internal combustion engine
EP2682580B1 (en) Exhaust emission control system for internal combustion engine, and control method for exhaust emission control system
EP2927448A1 (en) Exhaust purification system of internal combustion engine
US8086389B2 (en) Control apparatus for controlling both fuel injection system and exhaust gas cleaning system
JP5774300B2 (en) Exhaust purification equipment
JP4530778B2 (en) Method for adding reducing agent to NOx reduction catalyst

Legal Events

Date Code Title Description
AS Assignment

Owner name: HINO MOTORS, LTD., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:HOSOYA, MITSURU;SHIMODA, MASATOSHI;REEL/FRAME:021074/0775

Effective date: 20061003

STCB Information on status: application discontinuation

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