WO2008048175A1 - Procédé et agencement destinés à surveiller le fonctionnement d'un système de post-traitement des gaz d'échappement - Google Patents

Procédé et agencement destinés à surveiller le fonctionnement d'un système de post-traitement des gaz d'échappement Download PDF

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Publication number
WO2008048175A1
WO2008048175A1 PCT/SE2007/050703 SE2007050703W WO2008048175A1 WO 2008048175 A1 WO2008048175 A1 WO 2008048175A1 SE 2007050703 W SE2007050703 W SE 2007050703W WO 2008048175 A1 WO2008048175 A1 WO 2008048175A1
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Prior art keywords
exhaust gas
gas aftertreatment
sensor
measuring signal
catalyst
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PCT/SE2007/050703
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English (en)
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Lars Eriksson
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Scania Cv Ab (Publ)
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Publication of WO2008048175A1 publication Critical patent/WO2008048175A1/fr

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
    • F01N11/002—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity the diagnostic devices measuring or estimating temperature or pressure in, or downstream of the exhaust apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
    • F01N11/007—Monitoring 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
    • F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
    • F01N3/2066—Selective catalytic reduction [SCR]
    • F01N3/208—Control of selective catalytic reduction [SCR], e.g. dosing of reducing agent
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2550/00—Monitoring or diagnosing the deterioration of exhaust systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2550/00—Monitoring or diagnosing the deterioration of exhaust systems
    • F01N2550/02—Catalytic activity of catalytic converters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2550/00—Monitoring or diagnosing the deterioration of exhaust systems
    • F01N2550/04—Filtering activity of particulate filters
    • 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
    • F01N2560/021—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being an exhaust gas sensor for measuring or detecting ammonia NH3
    • 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
    • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/06—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being a temperature sensor
    • 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
    • F01N2610/03—Adding substances to exhaust gases the substance being hydrocarbons, e.g. engine fuel
    • 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
    • F01N2900/04—Methods of control or diagnosing
    • F01N2900/0404—Methods of control or diagnosing using a data filter
    • 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
    • F01N9/00—Electrical control of exhaust gas treating apparatus
    • F01N9/005—Electrical control of exhaust gas treating apparatus using models instead of sensors to determine operating characteristics of exhaust systems, e.g. calculating catalyst temperature instead of measuring it directly
    • 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
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

Definitions

  • the present invention relates to a method and a monitoring arrangement for monitoring the functioning of an exhaust gas aftertreatment system of a motor vehicle based on a measuring signal from a sensor as to the magnitude of a parameter related to exhaust gases flowing out of an exhaust gas aftertreatment appliance, for instance in the form of a catalyst or a filter, included in the exhaust gas aftertreatment system. Furthermore, the invention relates to a computer program comprising computer program code for implementing a method according to the invention, a computer program product comprising a data storage medium readable by an electronic control unit and having said computer program stored thereon, and an electronic control unit.
  • SCR Selective Catalytic Reduction
  • a method for monitoring an SCR catalyst is previously known from WO 2004/109072 A1 .
  • a temperature value representing the temperature of exhaust gases flowing out of the SCR catalyst is calculated by means of a calculation model and compared with a temperature value measured in the exhaust line downstream of the SCR catalyst. Based on the correspondence between these temperature values, such as for instance the difference between them, it is established whether or not the SCR catalyst and its injection device are functioning in a satisfying and expected manner.
  • Similar methods are also previously known from DE 4 122 787 A1 , US 5 860 277 A and EP 0 756 071 A2.
  • a problem associated with this type of monitoring methods relying on a calculation model is that the calculation model normally might give rather correct calculation values but at some operating conditions might give calculation values deviating substantially from the corresponding real values. Thus, incorrect fault indications might be generated based on test samples recorded during the last mentioned operating conditions.
  • the functioning of an SCR catalyst may also be monitored by means of a NO x sensor arranged to measure the NO x content in the exhaust gases downstream of the catalyst.
  • This NO x sensor may be supplemented by another NO x sensor arranged to measure the NO x content in the exhaust gases upstream of the catalyst in order to provide a comparison value.
  • a NO x sensor is an expensive component and one option for dispensing with a NO x sensor upstream of the catalyst is to use a calculation model for calculating the amount of NO x produced by the vehicle engine.
  • another calculation model may be used for calculating the expected conversion of NO x in the catalyst so as to obtain calculated values of the NO x content in the exhaust gases downstream of the catalyst.
  • calculated values may then be compared with the measuring values from the NO x sensor downstream of the catalyst in order to detect possible disorders of the catalyst and the associated equipment.
  • the use of calculation models for calculating the magnitude of the NO x content in the exhaust gases may however give calculation values deviating substantially from the corresponding real values, which in its turn may result in the generation of incorrect fault indications.
  • the object of the present invention is to propose a new and reliable manner of monitoring an exhaust gas aftertreatment system of a motor vehicle.
  • the functioning of the exhaust gas aftertreatment system is monitored based on a measuring signal from a sensor as to the magnitude of a parameter related to exhaust gases flowing out of an exhaust gas aftertreatment appliance, for instance in the form of a catalyst or a filter, included in the exhaust gas aftertreatment system.
  • a frequency analysis of the measuring signal supplied by the sensor during a certain period of time is performed so as to establish an evaluation value that reflects the character of a frequency part, preferably the high frequency part, of the measuring signal supplied by the sensor during this period of time.
  • the evaluation value is compared with a comparison value or a given threshold value in order to generate information regarding the functioning of the exhaust gas aftertreatment system
  • the inventive solution is based on the realization that a properly functioning exhaust gas aftertreatment appliance in the form of a
  • NO x reducing catalyst has an inertness that will cause a low-pass filtering effect on the NOx content in exhaust gases passing the catalyst, and that a properly functioning exhaust gas aftertreatment appliance in the form of a catalyst or particle filter has a temperature inertness that will cause a low-pass filtering effect on the temperature of exhaust gases passing the catalyst/filter.
  • a properly functioning exhaust gas aftertreatment appliance in the form of a catalyst or particle filter has a temperature inertness that will cause a low-pass filtering effect on the temperature of exhaust gases passing the catalyst/filter.
  • the measuring signal from a NO x sensor or temperature sensor arranged downstream of a catalyst or particle filter will comprise more high-frequency parts when the catalyst/filter is subjected to a disorder that reduces the efficiency thereof as compared to the case when the catalyst/filter is functioning properly.
  • a disorder that reduces the efficiency thereof as compared to the case when the catalyst/filter is functioning properly.
  • the monitoring of the exhaust gas aftertreatment system By basing the monitoring of the exhaust gas aftertreatment system on a frequency analysis of the measuring signal from a sensor, such as a temperature sensor or NO x sensor, arranged downstream of the exhaust gas aftertreatment appliance, it will be possible to generate information regarding the functioning of the exhaust gas aftertreatment system without being dependent on comparative calculation values from a complex and sometimes inaccurate calculation model, and without being dependent on measuring values from a corresponding sensor arranged upstream of the exhaust gas aftertreatment appliance. Furthermore, the monitoring will be insensitive to deviations between the real parameter values and the corresponding measuring values supplied by the sensor, which deviations for instance may be caused by offset errors of the sensor due to sensor drifting.
  • the evaluation value is chosen so as to represent the signal energy of a high-pass filtered measuring signal obtained by filtering the measuring signal supplied by the sensor during the evaluation period by means of a high-pass filter.
  • the evaluation value may be established in a simple and efficient manner.
  • the evaluation value may be established by evaluation of a frequency spectrum established by said frequency analysis.
  • the evaluation value is chosen as a value representing the estimated cutoff frequency of a low-pass filter model, which represents the signal filtering characteristics of the exhaust gas aftertreatment system with respect to said parameter and which is established by evaluation of the measuring signal from the sensor.
  • the comparison value is with advantage a stored value, which is established in advance and associated with specific operating conditions of the motor vehicle. In this case, a monitoring operation will only be carried out when the prevailing operating conditions of the motor vehicle correspond to operating conditions for which a comparison value has been established and stored.
  • the comparison value may alternatively be established in connection with the execution of a monitoring operation, based on measured or calculated values of the magnitude of said parameter of exhaust gases flowing into the exhaust gas aftertreatment appliance or based on calculated values of the magnitude of said parameter of exhaust gases flowing out of the exhaust gas aftertreatment appliance.
  • the invention also relates to a computer program having the features defined in claim 16, a computer program product having the features defined in claim 17 and an electronic control unit having the features defined in claim 18.
  • Fig 1 is a schematic diagram of a combustion engine with an associated exhaust gas aftertreatment system, illustrating an embodiment of a monitoring arrangement according to the present invention
  • Fig 2 is a diagram showing an exemplifying measuring signal from a sensor as a function of time
  • Fig 3 is a diagram showing the frequency spectrum of the measuring signal of Fig 2
  • Fig 4 is an exemplifying Bode plot representing the frequency response of a catalyst included in an exhaust gas aftertreatment appliance
  • Fig 5 is a schematic outline diagram of an electronic control unit for implementing a method according to the invention.
  • Fig 6 is a flow diagram illustrating a method according to an embodiment of the invention.
  • An inventive monitoring method and monitoring arrangement will in the following be described as implemented to monitor the functioning of an exhaust gas aftertreatment system comprising an exhaust gas aftertreatment appliance in the form of a catalyst.
  • the invention is in no way limited to this utilization.
  • the invention may be utilized for monitoring an exhaust gas aftertreatment system having any type of exhaust gas aftertreatment appliance that has a low-pass filtering effect on a measurable exhaust gas parameter.
  • the invention may for instance be used for monitoring the functioning of an exhaust gas aftertreatment system comprising an exhaust gas aftertreatment appliance in the form of a filter, such as a particle filter or an open structure filter.
  • a combustion engine 1 with an associated exhaust gas aftertreatment system 2 is schematically shown in Fig 1 .
  • the exhaust gases leaving the combustion engine 1 are conveyed through an exhaust line 3 and are discharged into the surroundings via an exhaust outlet 4.
  • a catalyst 5 is arranged in the exhaust line 3. The exhaust gases from the combustion engine 1 will pass the catalyst 5 before being discharged into the surroundings via the exhaust outlet 4.
  • the catalyst 5 is an SCR catalyst.
  • reducing agent is injected by means of an injection device 6 into the exhaust gases in the exhaust line 3 upstream of the catalyst 5.
  • the injection device 6 comprises one or several injection members 7 in the form of injection nozzles or the like arranged in the exhaust line 3, and a reducing agent storage container 8 connected thereto.
  • the injection device 6 also comprises a regulating member 9, e.g. in the form of a control valve, arranged to regulate the supply of reducing agent to said one or several injection members 7, and a control means 10 connected to the regulating member 9.
  • the regulating member 9 is controlled by said control means 10, which determines, on the basis of the prevailing operating conditions of the combustion engine 1 and the catalyst 5, the amount of reducing agent to be injected into the exhaust gases.
  • the injection device 6 may also comprise further components, such as a dosing appliance etc.
  • the reducing agent may be urea (CO(NH 2 ) 2 ), ammonia (NH 3 ) or hydrocarbon (fuel).
  • a sensor 1 1 is arranged in the exhaust line 3 downstream of the catalyst 5.
  • the sensor 1 1 is a NO x sensor arranged to generate a measuring signal representing the NO x content in the exhaust gases flowing out of the catalyst 5, i.e. the NO x content in the exhaust gases at the outlet of the catalyst.
  • the measuring signal may be a continuous signal representing the continuous changes of the measured parameter, i.e. forming a continuous stream of measuring values as to the magnitude of the parameter, but is normally recorded as a discrete-time signal forming a series of consecutive and discrete measuring values as to the magnitude of the parameter.
  • the monitoring arrangement 20 comprises processing means 21 arranged to receive the measuring signal from the sensor 1 1 as to the measured magnitude of the NO x content in the exhaust gases downstream of the catalyst 5.
  • the processing means 21 is adapted to perform a frequency analysis of the measuring signal supplied by the sensor 1 1 during a certain period of time T ev , here denominated evaluation period, and to generate information regarding the functioning of the exhaust gas aftertreatment system 2 based on said frequency analysis.
  • the catalyst If the catalyst is functioning properly, it will under normal operating conditions of the combustion engine 1 and the catalyst 5 have a general reducing effect on the NO x content of the exhaust gases passing through the catalyst and will also dampen peak values and rapidly varying fluctuations of the NO x content occurring in the exhaust gases upstream of the catalyst 5 in such a manner that these peak values and fluctuations have been eliminated or at least substantially reduced when the exhaust gases leave the catalyst.
  • the catalyst resembles a low-pass filter and will have a low-pass filtering effect on the magnitude of the NO x content of the exhaust gases passing through the catalyst 5.
  • the measuring signal from the sensor 1 1 resembles a low-pass filtered signal.
  • the low-pass filtering effect varies with variations in the NO x reducing efficiency of the catalyst.
  • the processing means 21 is adapted to establish an evaluation value V ev that reflects the character of a frequency part, preferably the high frequency part, of the measuring signal supplied by the sensor during the evaluation period T ev .
  • the processing means 21 is then adapted to compare this evaluation value V ev with a comparison value V co or a given threshold value V th in order to generate information regarding the functioning of the catalyst 5 and the associated exhaust gas aftertreatment system 2.
  • the measuring signal supplied by the sensor 1 1 during the evaluation period T ev is filtered by means of a high-pass filter 22 and the evaluation value V ev is chosen so as to represent the signal energy of the high-pass filtered measuring signal.
  • This signal energy may be calculated in any suitable and conventional manner with the aid of an algorithm known to a person skilled in the art.
  • the established evaluation value V ev may then be compared with a signal energy representing comparison value V co or a given threshold value V th .
  • the comparison value V co may for instance be chosen so as to represent the signal energy of a previously high-filtered measuring signal from the sensor 1 1 recorded during a period of time when the catalyst and the associated exhaust gas aftertreatment system were known to function properly or the signal energy of a correspondingly high-pass filtered signal established by means of suitable calculation models.
  • the processing means 21 is suitably adapted generate a fault indication if the difference or ratio between the evaluation value V ev and the comparison value V co exceeds a threshold level so as to thereby indicate a functional disorder of the system.
  • a frequency spectrum of the measuring signal supplied by the sensor 1 1 during the evaluation period is established by frequency analysis of said measuring signal.
  • This frequency spectrum may be established in any suitable and conventional manner with the aid of an algorithm known to a person skilled in the art, such as for instance the algorithm denominated Fast Fourier Transform (FFT).
  • FFT algorithm denominated Fast Fourier Transform
  • Fig 3 shows a frequency spectrum 23 established by FFT based on the measuring signal 24 shown in Fig 2.
  • the frequency spectrum shows the magnitude of each frequency component of the measuring signal.
  • the frequency spectrum of the measuring signal from the sensor 1 1 is the product of the frequency spectrum of a signal representing the magnitude of the parameter in question upstream of the catalyst 5 and the frequency response of the catalyst.
  • the established frequency spectrum 23 may be evaluated in any suitable manner in order to establish the evaluation value V ev -
  • the evaluation value may for instance be established from a frequency spectrum by the formula:
  • V ev ⁇ high Y(f)/ ⁇ tot Y(f)
  • - Y(f) is the y-axis value for the frequency f in said frequency spectrum
  • Y(f) is the sum of Y(f) across a selected high frequency part of said frequency spectrum
  • the processing means 21 is suitably adapted generate a fault indication if the evaluation value V ev exceeds the threshold value V th so as to thereby indicate a functional disorder of the exhaust gas aftertreatment system.
  • a low-pass filter model representing the signal filtering characteristics of the exhaust gas aftertreatment system with respect to said parameter is established by evaluation of the measuring signal from the sensor 1 1 during the evaluation period T ev -
  • This low-pass filter model may be established in any suitable and conventional manner with the aid of an algorithm known to a person skilled in the art, such as for instance by autoregressive Modeling or autoregressive Moving Average Modeling.
  • the evaluation value V ev is chosen as a value representing the estimated cutoff frequency of the low-pass filter model.
  • a Bode plot 25 associated with an established low-pass filter model in the form of an autoregressive Model of the first order is shown in Fig 4.
  • the cutoff frequency f cut is indicated in the Bode plot of Fig 4.
  • the established evaluation value V ev may then be compared with a comparison value V co representing the cutoff frequency of a comparative low-pass filter model or a given threshold value V th .
  • the comparison value V co may for instance be chosen so as to represent the cutoff frequency of a comparative low-pass filter model previously established based on a measuring signal from the sensor 1 1 recorded during a period of time when the catalyst and the associated exhaust gas aftertreatment system were known to function properly or based on a corresponding signal established by means of suitable calculation models.
  • the length of the evaluation period T ev and the interval between each monitoring operation may of course vary widely from case to case depending on the nature of the system to be monitored.
  • the evaluation period may for instance be in the order of 10-30 seconds or longer.
  • a suitable comparison value V co or threshold value V th may be established empirically by practical tests and/or theoretically on the basis of suitable calculations.
  • the comparison value V co or threshold value V th is with advantage a stored value, which is established in advance and associated with specific operating conditions of the motor vehicle.
  • the comparison value V co may alternatively be established in connection with the execution of a monitoring operation, based on measured or calculated values of the magnitude of said parameter of exhaust gases flowing into the exhaust gas aftertreatment appliance 5 or based on calculated values of the magnitude of said parameter of exhaust gases flowing out of the exhaust gas aftertreatment appliance 5.
  • the monitoring arrangement 20 suitably comprises some sort of indicating device for displaying an error message and/or emitting an acoustic or luminous warning signal when a fault of the monitored system has been detected.
  • An abnormal evaluation value V ev indicates that the catalyst 5 and/or any other component of the exhaust gas aftertreatment system 2, such as for instance the injection device 6 or the sensor 1 1 , is not functioning satisfyingly, and may for instance be due to one or more of the following causes:
  • the injection device 6 does not inject the expected amount of the expected reducing agent
  • the processing means 21 is with advantage a computer unit, for instance in the form of an electronic control unit of a motor vehicle.
  • the embodiment examples described above in connection with the monitoring of an exhaust gas aftertreatment system provided with an exhaust gas aftertreatment appliance in the form of an SCR catalyst easily could be modified in order to monitor the functioning of an exhaust gas aftertreatment system provided with any other type of exhaust gas aftertreatment appliance having an inertness with respect to the measured parameter in question, such as another type of catalyst or a filter.
  • the parameter could for instance be the temperature of the exhaust gases flowing out of a catalyst or a filter, in which case the above-indicated sensor is a temperature sensor arranged downstream of the catalyst/filter.
  • the parameter could also be the ammonia content of the exhaust gases flowing out of an SCR catalyst operated with a reducing agent in the form of urea or ammonia, in which case the above-indicated sensor is an ammonia sensor arranged downstream of the catalyst.
  • a flow diagram illustrating a method according to an embodiment of the invention is shown in Fig 6.
  • a measuring signal from a sensor 1 1 as to the magnitude of a parameter related to exhaust gases flowing out of an exhaust gas aftertreatment appliance is recorded during a certain period of time T ev -
  • a frequency analysis of the recorded measuring signal is performed so as to establish an evaluation value V ev that reflects the character of a frequency part, preferably the high frequency part, of the measuring signal supplied by the sensor 1 1 during said period of time T ev -
  • the evaluation value V ev is compared with a comparison value V co or a given threshold value V th in order to generate information regarding the functioning of the exhaust gas aftertreatment system, whereupon the monitoring cycle is terminated in step S4.
  • Computer program code for implementing a method according to the invention is suitably included in a computer program, which is loadable into the internal memory of a computer, such as the internal memory of an electronic control unit of a motor vehicle comprising an exhaust gas aftertreatment system to be monitored.
  • a computer program is suitably provided via a computer program product comprising a data storage medium readable by an electronic control unit, which data storage medium has the computer program stored thereon.
  • Said data storage medium is for instance an optical data storage medium in the form of a CD-ROM disc, a DVD disc etc, a magnetic data storage medium in the form of a hard disc, a diskette, a cassette tape etc, or a memory of the type ROM, PROM, EPROM or EEPROM or a Flash memory.
  • Fig 5 very schematically illustrates an electronic control unit 30 comprising an execution means 31 , such as a central processing unit (CPU), for executing computer software.
  • the execution means 31 communicates with a memory 33, for instance of the type RAM, via a data bus 32.
  • the control unit 30 also comprises data storage medium 34, for instance in the form of a memory of the type ROM, PROM, EPROM or EEPROM or a Flash memory.
  • the execution means 31 communicates with the data storage medium 34 via the data bus 32.
  • a computer program comprising computer program code for implementing a method according to the invention is stored on the data storage medium 34.

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

Abstract

L'invention concerne un procédé et un agencement destinés à surveiller le fonctionnement d'un système de post-traitement des gaz d'échappement (2) d'un véhicule à moteur, sur la base d'un signal de mesure issu d'un capteur (11) relatif à la magnitude d'un paramètre concernant les gaz d'échappement s'écoulant hors d'un dispositif de post-traitement des gaz d'échappement (5), par exemple sous la forme d'un catalyseur ou d'un filtre, contenu dans le système de post-traitement des gaz d'échappement (2). Une analyse de fréquence (10) du signal de mesure fourni par le capteur (11) pendant un certain laps de temps est réalisée de manière à établir une valeur d'évaluation qui reflète les caractéristiques d'une partie de fréquence du signal de mesure fourni par le capteur pendant ce laps de temps. Des informations concernant le fonctionnement (15) du système de post-traitement des gaz d'échappement (2) sont générées sur la base de cette valeur d'évaluation.
PCT/SE2007/050703 2006-10-19 2007-10-03 Procédé et agencement destinés à surveiller le fonctionnement d'un système de post-traitement des gaz d'échappement WO2008048175A1 (fr)

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SE0602190A SE530435C2 (sv) 2006-10-19 2006-10-19 Förfarande och inrättning för övervakning av funktionen hos ett avgasefterbehandlingssystem
SE0602190-1 2006-10-19

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WO2008048175A1 true WO2008048175A1 (fr) 2008-04-24

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2956987A1 (fr) * 2010-03-02 2011-09-09 Peugeot Citroen Automobiles Sa Procede de detection du fonctionnement defaillant d'un filtre a particules d'un systeme anti-pollution
FR2970749A1 (fr) * 2011-01-20 2012-07-27 Bosch Gmbh Robert Procede de surveillance des fonctions d'un systeme de dosage, notamment applique a un catalyseur rcs.
WO2015090521A1 (fr) * 2013-12-19 2015-06-25 Daimler Ag Procédé et ensemble de commande pour faire fonctionner un système de gaz d'échappement

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5771685A (en) * 1996-10-16 1998-06-30 Ford Global Technologies, Inc. Method for monitoring the performance of a NOx trap
EP1434049A1 (fr) * 2002-12-29 2004-06-30 Volkswagen AG Procédé et dispositif pour surveiller le signal NOx d'un capteur de NOx
DE102004052063A1 (de) * 2004-10-26 2006-04-27 Volkswagen Ag Vorrichtung und Verfahren zur Regenerierung von Speicherkatalysatoren
US20060137326A1 (en) * 2004-12-27 2006-06-29 Mitsubishi Jidosha Kogyo Kabushiki Kaisha Control device for an internal combustion engine

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5771685A (en) * 1996-10-16 1998-06-30 Ford Global Technologies, Inc. Method for monitoring the performance of a NOx trap
EP1434049A1 (fr) * 2002-12-29 2004-06-30 Volkswagen AG Procédé et dispositif pour surveiller le signal NOx d'un capteur de NOx
DE102004052063A1 (de) * 2004-10-26 2006-04-27 Volkswagen Ag Vorrichtung und Verfahren zur Regenerierung von Speicherkatalysatoren
US20060137326A1 (en) * 2004-12-27 2006-06-29 Mitsubishi Jidosha Kogyo Kabushiki Kaisha Control device for an internal combustion engine

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2956987A1 (fr) * 2010-03-02 2011-09-09 Peugeot Citroen Automobiles Sa Procede de detection du fonctionnement defaillant d'un filtre a particules d'un systeme anti-pollution
WO2011107686A1 (fr) * 2010-03-02 2011-09-09 Peugeot Citroën Automobiles SA Procede de detection du fonctionnement defaillant d'un filtre a particules d'un systeme anti-pollution
FR2970749A1 (fr) * 2011-01-20 2012-07-27 Bosch Gmbh Robert Procede de surveillance des fonctions d'un systeme de dosage, notamment applique a un catalyseur rcs.
WO2015090521A1 (fr) * 2013-12-19 2015-06-25 Daimler Ag Procédé et ensemble de commande pour faire fonctionner un système de gaz d'échappement
US10724413B2 (en) 2013-12-19 2020-07-28 Dailer AG Method and control assembly for operating an exhaust gas system

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SE0602190L (sv) 2008-04-20

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