WO2014035324A1 - Procédé et système pour établir une fonction de capteur pour un capteur pm dans un flux de gaz d'échappement - Google Patents

Procédé et système pour établir une fonction de capteur pour un capteur pm dans un flux de gaz d'échappement Download PDF

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Publication number
WO2014035324A1
WO2014035324A1 PCT/SE2013/051006 SE2013051006W WO2014035324A1 WO 2014035324 A1 WO2014035324 A1 WO 2014035324A1 SE 2013051006 W SE2013051006 W SE 2013051006W WO 2014035324 A1 WO2014035324 A1 WO 2014035324A1
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WO
WIPO (PCT)
Prior art keywords
sensor
change
exhaust stream
supply
signal
Prior art date
Application number
PCT/SE2013/051006
Other languages
English (en)
Inventor
Ola Stenlåås
Original Assignee
Scania Cv Ab
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 Scania Cv Ab filed Critical Scania Cv Ab
Priority to DE112013003883.8T priority Critical patent/DE112013003883B4/de
Publication of WO2014035324A1 publication Critical patent/WO2014035324A1/fr

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Classifications

    • 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
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/22—Safety or indicating devices for abnormal conditions
    • F02D41/222—Safety or indicating devices for abnormal conditions relating to the failure of sensors or parameter detection devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/14—Introducing closed-loop corrections
    • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
    • F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
    • F02D41/1466—Introducing 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 a soot concentration or content
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/22—Safety or indicating devices for abnormal conditions
    • 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
    • F01N2560/05—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being a particulate 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
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/033—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices
    • F01N3/035—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters in combination with other devices with catalytic reactors, e.g. catalysed diesel 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
    • 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
    • F01N3/105—General auxiliary catalysts, e.g. upstream or downstream of the main catalyst
    • F01N3/106—Auxiliary oxidation catalysts
    • 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
    • F01N9/00—Electrical control of exhaust gas treating apparatus
    • F01N9/002—Electrical control of exhaust gas treating apparatus of filter regeneration, e.g. detection of clogging
    • 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
    • Y02T10/40—Engine management systems

Definitions

  • the present invention pertains to a system for the treatment of exhaust streams resulting from a combustion process, and in particular to by which a sensor function for a PM sensor is confirmed according to the preamble of patent claim 1.
  • the invention also relates to a system and a vehicle, as well as a computer program and a computer program product, which
  • Such emission regulations often consist of requirements which define acceptable limits for exhaust emissions in vehicles equipped with combustion engines. For example, levels of nitrogen oxides (NO x ) , hydrocarbons (HC) and carbon monoxide (CO) are often regulated. These emission regulations usually also pertain to, at least in relation to certain types of vehicles, the presence of particles in exhaust emissions.
  • NO x nitrogen oxides
  • HC hydrocarbons
  • CO carbon monoxide
  • exhausts caused by the combustion of the combustion engine are treated (purified) .
  • purification process a so-called catalytic purification process may be used, so that aftertreatment systems in e.g. vehicles and other vessels usually comprise one or more catalysts.
  • aftertreatment systems often comprise, as an alternative to or in combination with a single or several catalysts, other components.
  • the combustion of fuel in the combustion chamber e.g.
  • soot particles forms soot particles. According to the above, there are emission regulations and standards also pertaining to these soot particles, and in order to comply with the
  • particulate filters may be used to catch soot particles.
  • the exhaust stream is led e.g.
  • PM Particulate Matter, Particulate Mass
  • Particle concentration may be determined e.g. as a particle mass per volume or weight unit, or as a certain number of particles of a certain size per volume unit, and several determinations of the amount of particles of varying sizes may be used to determine particle emission .
  • Aftertreatment systems with particulate filters may be very efficient, and the resulting particle concentration after the passage of the exhaust stream through the aftertreatment system of the vehicle is often low with a fully functional aftertreatment system. This also means that the signals which the sensor emits will indicate a low or no particle emission.
  • One objective of the present invention is to provide a method to establish a sensor function for a PM sensor intended to determine a particle concentration in an exhaust stream resulting from combustion in a combustion engine. This objective is achieved with a method according to patent claim 1.
  • the present invention pertains to a method to establish a sensor function for a PM sensor intended for the determination of a particle concentration in an exhaust stream resulting from combustion in a combustion engine, where an
  • the method comprises :
  • PM sensors may be used to ensure that the level of particles in the exhaust stream resulting from the combustion engine does not exceed stipulated levels.
  • a PM sensor may be set up at various points in the exhaust stream, and depending on its position, a PM sensor may be set up so that the presence of particles at the location of the PM sensor is very small. This applies e.g. to a PM sensor which is set up downstream from a particulate filter, where a correctly functioning particulate filter is often capable of separating a very significant part of the particles emitted from the combustion engine's combustion chamber.
  • the PM sensor may as such emit a signal representative of the environment in which the PM sensor is located, where the PM sensor and/or the aftertreatment system have been manipulated so that the sensor no longer measures particle concentration in a representative exhaust stream.
  • the senor may have been moved from the intended position in the exhaust stream to e.g. a position where it measures particle concentration in the vehicle's surroundings.
  • the PM sensor will always emit a signal representing a very low or no particle concentration
  • Another way of manipulating the signal emitted by the PM sensor in order to reduce the detected particle concentration is to divert all or part of the exhaust stream past the PM sensor, so that the latter is no longer exposed to a
  • the PM sensor may also be induced to emit signals representing a lower particle concentration than what is actually the case.
  • Another way of manipulating the sensor signal is by blocking the sensor so that the exhaust stream is not led through the sensor .
  • a method is provided in order to determine whether the PM sensor may be assumed to emit a representative signal and to determine whether the sensor is faulty or if it has been manipulated.
  • SCR catalysts usually use ammoniac (NH 3 ) , or a composition from which ammonia may be generated/formed, e.g. urea, as an additive for the reduction of nitrogen oxides NO x in the exhaust stream.
  • This additive is injected into the exhaust stream resulting from the combustion engine upstream from the SCR catalyst and the additive added to the catalyst is
  • the signal emitted by at least some PM sensors i.e. the signal which normally constitutes a representation of the particle concentration in the exhaust stream, is cross-sensitive to such additives. This cross- sensitivity entails that the PM sensor reacts to the presence of an additive in the exhaust stream and thus generates a signal which indicates a higher concentration of particles than the actual level.
  • This realisation is used according to the present invention in such a manner that a change in a signal emitted by one of the said PM sensors in response to a change in the supply of additives is determined, and based on the change in the signal emitted by the PM sensor, it is determined whether the said PM sensor emits a signal which is representative of the said exhaust stream.
  • the PM sensor does not carry out measurements of a representative exhaust stream, i.e. an exhaust stream which correctly reflects the
  • composition in the exhaust stream which leaves the combustion engine's combustion chamber, and thus malfunctions or has been manipulated .
  • Fig. la shows a diagram of a vehicle in which the present invention may be used.
  • Fig. lb shows a control device in the control system for the vehicle in Fig. 1.
  • Fig. 2 shows the aftertreatment system in more detail for the vehicle in Fig. 1.
  • Fig. 3 shows an example embodiment according to the present inventio .
  • Fig. 4 shows an alternative example embodiment according to the present invention.
  • the expression particle concentration comprises, in the description below and the subsequent patent claim,
  • concentration in the form of mass per unit and concentration as number of particles per unit may be comprised of any applicable unit and the concentration may be expressed as, for example, mass or number of particles per volume unit, per mass unit, per time unit, per work completed, or per distance travelled by the vehicle.
  • Fig. 1A shows a diagram of a driveline in a vehicle 100 according to an embodiment of the present invention.
  • the diagram of the vehicle 100 in Fig. 1A comprises only one shaft with wheels 113, 114, but the invention is applicable also to vehicles where more than one shaft is equipped with wheels, and vehicles with one or more shafts, such as one or more support shafts.
  • the driveline comprises one combustion engine 101, which in a customary manner, via an output shaft on the combustion engine 101, usually via a flywheel 102, is
  • the combustion engine 101 is controlled by the engine's control system via a control device 115.
  • the clutch 106 which may consist of e.g. an automatically controlled clutch, as well as the gearbox 103 are controlled by the vehicle's control system with the help of one or more
  • vehicle's driveline may also be of another type such as a type with a conventional automatic gearbox, etc.
  • An output shaft 107 from the gearbox 103 drives the wheels 113, 114 via a final drive 108, such as a customary
  • the vehicle 100 also comprises an exhaust system with an aftertreatment system 200 for treatment (purification) of exhaust emissions resulting from combustion in the combustion chamber (e.g. cylinders) of the combustion engine 101.
  • an aftertreatment system 200 for treatment (purification) of exhaust emissions resulting from combustion in the combustion chamber (e.g. cylinders) of the combustion engine 101 e.g. cylinders
  • FIG. 2 One example of an aftertreatment system 200 is displayed in more detail in Fig. 2.
  • the figure shows the combustion engine 101 of the vehicle 100, where the exhaust generated by the combustion (the exhaust stream) is led via a turbocharger 220.
  • the exhaust stream resulting from the combustion often drives a turbocharger which in turn
  • turbocharger may e.g. be of compound type.
  • the function of various types of turbochargers is well-known, and is therefore not described in any detail herein.
  • the exhaust stream is subsequently led via a pipe 204 (indicated with arrows) to a diesel particulate filter (DPF) 202 via a diesel oxidation catalyst (DOC) 205.
  • DPF diesel particulate filter
  • DOC diesel oxidation catalyst
  • the DOC 205 has several functions, and is normally used primarily in the aftertreatment to oxidise remaining
  • hydrocarbons and carbon monoxide in the exhaust stream into carbon dioxide and water.
  • heat is also formed, which may be used to increase the particulate filter's temperature when e.g. the particulate filter is emptied (regenerated) .
  • the oxidation catalyst 205 may also oxidise nitric oxide (NO) to nitrogen dioxide (NO 2 ) , which is used for e.g. N0 2 ⁇ based regeneration. Further reactions may occur in an oxidation catalyst .
  • NO oxidise nitric oxide
  • NO 2 nitrogen dioxide
  • the aftertreatment system may comprise more components than indicated in the examples above, or fewer components.
  • the aftertreatment system may, as in the present example, comprise a SCR (Selective Catalytic Reduction) catalyst 201 downstream of the particulate filter 202.
  • SCR catalysts use ammoniac (N3 ⁇ 4) , or a composition from which ammoniac may be generated/formed, as an additive to reduce the amount of nitrogen oxides NO x in the exhaust stream.
  • This additive may, according to the present invention, be used to determine whether the PM sensor emits a representative signal.
  • the components DOC 205, DPF 202 and the SCR catalyst 201 are integrated into one and the same exhaust purification unit 203. However, it should be
  • Fig. 2 also shows temperature sensors 210-212 and a differential pressure sensor 209.
  • the figure also shows a PM sensor 213, whose function is determined according to the present invention, and which is shown downstream of the exhaust purification unit 203 in the present example.
  • the PM sensor may also be set up upstream of the exhaust purification unit 203, as well as upstream of the turbocharger 220.
  • the vehicle's exhaust system may comprise more than one PM sensor, which may be set up at various positions, and by virtue of which the functionality of all the PM sensors in the vehicle may be assessed.
  • the PM sensor 213 is, in the present invention, integrated or collocated with a concentration/fraction sensor 214, where the
  • concentration/fraction sensor 214 is adapted to determine the concentration of some applicable substance normally occurring in the exhaust stream. As mentioned above, soot particles are formed during the combustion of the combustion engine 101, and these soot particles may in many cases not be emitted into the exhaust stream.
  • the soot particles are caught by the particulate filter 202, which functions so that the exhaust stream is led through a filter structure where soot particles are caught from the passing exhaust stream and subsequently stored in the particulate filter 202. With the help of the particulate filter 202, a very large part of the particles may be separated from the exhaust stream.
  • the PM sensor 213 may be used to control that the particulate filter 202 functions in the desired manner, but also to monitor e.g. the functionality of the combustion engine 101 in the event of e.g. a PM sensor position upstream from the particulate filter.
  • the PM sensor 213 may also be used for other purposes.
  • the PM sensor 213 must emit signals which are representative of the environment in which the PM sensor is intended to be representative
  • Fig. 3 shows an example embodiment 300, according to the present invention, with the help of which the PM sensor may be assessed and incorrect sensor signals contingent on non-representative exhaust streams may be detected.
  • the method is carried out according to the present example of the control device 208 shown in Fig. 1A-B and Fig. 2.
  • control systems in modern vehicles consist of a communication bus system consisting of one or more
  • ECUs electronice control devices
  • Such a control system may comprise a large number of control devices, and the responsibility for a specific function may be distributed among more than one control device.
  • FIG. 1A-B shows only the control devices 115, 208.
  • the present invention is thus in the embodiment displayed implemented in the control device 208, which in the embodiment displayed may be in charge of other functions as well in the aftertreatment system 200, such as regeneration (emptying) of the particulate filter 202, but the invention may thus also be implemented in a control device dedicated to the present invention, or wholly or partly in one or more other control devices already existing in the vehicle, such as the engine control device 115.
  • control device 208 or the control device (s) in which the present invention is implemented
  • a sensor 210 for determination of a concentration and/or fraction of a substance
  • control device (s) which control the engine's
  • Control devices of the type displayed are normally arranged to receive sensor signals from different parts of the vehicle.
  • the control device 208 may e.g. receive sensor signals as per the above, and from other control devices than the control device 115.
  • Such control devices are further usually set up to emit control signals to different parts and components of the vehicle.
  • the control device 208 may emit signals to e.g. the engine control device 115.
  • Control is often controlled by programmed instructions.
  • These programmed instructions typically consist of a computer program, which, when it is executed in a computer or control device, causes the computer/control device to carry out the desired steering, as a method step in the process according to the present invention.
  • the computer program usually consists of a computer program product, where the computer program product comprises an applicable storage medium 121 (see Fig. IB) with the computer program 109 stored on the said storage medium 121.
  • the said digital storage medium 121 may e.g. consist of any from the following group: ROM (Read-Only Memory), PROM (Programmable Read-Only Memory) , EPROM (Erasable PROM) , Flash, EEPROM
  • control device 208 is displayed in the diagram in Fig. IB, and the control device in turn may comprise a calculation unit 120, which may consist of e.g. a suitable type of processor or microcomputer, e.g. a circuit for digital signal processing (Digital Signal Processor, DSP) , or a circuit with a specific function (Application Specific Integrated Circuit, ASIC) .
  • the calculation unit 120 is connected to a memory unit 121, which provides the calculation unit 120 with e.g. the stored program code 109 and/or the stored data which the calculation unit 120 needs in order to be able to carry out calculations.
  • the calculation unit 120 is also set up to store interim or final results of calculations in the memory unit 121.
  • control device is equipped with devices 122, 123, 124, 125 for receipt and sending of input and output signals.
  • These input and output signals may contain waveforms, pulses, or other attributes, which may be detected by the devices 122, 125 for the receipt of input signals that may be detected as information for processing of the calculation unit 120.
  • the devices 123, 124 for sending output signals are arranged to convert the calculation result from the calculation unit 120 to output signals for transfer to other parts of the vehicle's control system and/or the component (s) for which the signals are intended.
  • Each one of the connections to the devices for receipt and sending of input and output signals may consist of one or several cables; or data buses, such as a CAN
  • Fig. 3 shows a first example embodiment 300, according to the present invention. The method begins at step 301, where it is
  • step 302. The transfer from step 301 to step 302 may e.g. be arranged to be controlled by the time elapsed since a previous evaluation of the PM sensor 213.
  • the PM sensor 213 may also be arranged to be evaluated continuously, with applicable intervals, each time the vehicle starts or at other suitable times, e.g. if for any reason, e.g. based on PM sensor signals emitted or signals from other sensors/units, it may be
  • a change in the signal Si emitted by the PM sensor 213 is established, where the signal emitted Si generally represents particulate matter in the exhaust stream.
  • This change may e.g. be represented by a frequency for an amplitude variation, i.e. the signal Si emitted may show amplitude peaks with a certain frequency.
  • This determination may e.g. be established by applicable signal processing.
  • the change confirmed at step 302 may also consist of another applicable determination, such as confirming an amplitude change which arises for subsequent comparison, according to the below, with an expected change.
  • step 303 a corresponding change in the supply of additives to the exhaust stream is established.
  • This change may e.g. consist of a determination of the frequency at which the additives are supplied to the exhaust stream.
  • the dosage of the additive is normally achieved with the use of e.g. an injector fitted in the exhaust system, and the injection is carried out with an applicable injection length at an
  • the change in supply of additives may also consist of e.g. a change in the injection frequency, or consist of a change of the injected amount of additive, or any applicable combination of these changes.
  • the change in additive supplied may be controlled by factors separate from the present invention, where such a change is only observed, but the change may also be arranged to be regulated by the present invention through a separate step preceding step 303 in Fig. 3.
  • step 304 the change in the signal emitted by the PM sensor is compared with the change in the supply of additives.
  • the frequency of the amplitude peaks in the signal emitted by the PM sensor may be compared to the dosage frequency. If these frequencies are consistent with each other to any applicable extent, it may be assumed that the PM sensor carries out measurements in the exhaust stream into which the additives are supplied, and in all likelihood it is therefore subjected to a representative exhaust stream.
  • a change in amplitude during any applicable period in the signal emitted by the PM sensor may be compared with an expected amplitude change caused by the change in the amount of additive supplied.
  • step 305 it is confirmed whether the comparison indicates that the PM sensor 213 emits a representative signal, and if so, the method continues to step 301.
  • the comparison indicates that the PM sensor 213 does not emit a representative signal
  • the method continues to step 306, where an error signal is generated, e.g. an alarm signal and/or error code, in order for the control system of the vehicle 100 to indicate that the PM sensor 213 cannot be deemed to emit a representative signal since it is not deemed to be subjected to a representative exhaust stream.
  • the signal generated may e.g. be used by the control system of the vehicle 100 in order to set the status of the vehicle 100 to a status where the vehicle 100 is in immediate need of service for action by the PM sensor 213.
  • the control system may also be arranged to limit the functionality of the vehicle 100, e.g. by limiting the maximum output of the combustion engine 101 of the vehicle 100 until the fault is remedied.
  • the method is then completed at step 307.
  • an active measure which is specifically intended to change the supply of additives may, but need not be, carried out and the
  • determination according to the present invention may be carried out when the vehicle is driven in such a way that there is a detectable change in the supply of additives anyway, e.g. achieved by the pulsation which is normally applied in the supply of additives or how the amount of additives changes.
  • FIG. 4 an example embodiment 400, according to the present invention, is shown, where a change in the supply of additives is implemented actively.
  • step 401 The method starts at step 401, and the transition to step 402 may be controlled according to the above description.
  • step 402 an initial representation Pi of the particulate matter in the exhaust stream is confirmed with the use of the said PM sensor 213.
  • step 403 a change in the supply of additives is carried out.
  • This change may be carried out in various ways and involves, according to one embodiment, completely shutting off the supply of additives to the exhaust stream, or changing the amount of additives which is supplied to the exhaust stream.
  • the supply of additives may be shut off instead, or may be shut off at a step preceding step 403, and the supply may be reactivated at step 403.
  • the injection frequency or the amount of additives supplied may also be altered.
  • no measure is taken, however, which is specifically intended to change the supply according to the invention, instead at step 403 it is expected that the applicable change of the supplied additives is made for another reason controlled by the vehicle's control system, where such change may consist of any of the examples herein or another applicable change.
  • the method continues in one embodiment to a step where the method waits for an initial time period tl in order to compensate for any potential delays in the system, so that the effects of previously supplied additives may be diminished or at least reduced.
  • the said initial time period may e.g. be controlled by the additive injector's position in the exhaust system in relation to the PM sensor and the number/type of components which are installed in between.
  • the time period tl may be brief, and according to the
  • this waiting step is not applied.
  • step 403 a second representation of the particulate matter in the exhaust stream is confirmed with the use of the said PM sensor 213, i.e. a particle concentration P 2 is confirmed at the PM sensor 213 after the said measure to change the supply of additives has been completed.
  • an expected PM sensor signal change is then confirmed AP exp (at the position of the PM sensor 213 after the change made at step 403 in the supply of additives, and the change AP J2 at step 406 between the said initial Pi and the second particle concentration indicated by the PM sensor P 2 is compared with the expected change in the particle
  • this signal difference may be converted to a particle concentration difference or compared to an expected signal difference.
  • the expected particle concentration change ⁇ ⁇ i.e. it is sufficient to confirm an expected difference without
  • the expected particle concentration change P SAP may e.g. be confirmed by table lookup, where the signal emitted by the PM sensor expected for various dosages may be specified, where this expected specified signal may constitute the signal difference which the additive as such is expected to give rise to due to cross-sensitivity, and which thus constitutes the difference signal which the additive causes.
  • the actual particle concentration (sensor signal) change hP 12 is then compared to the expected change in particle concentration ⁇ 6 ⁇ , where a discrepancy A between the expected particle concentration change AP e ⁇ P and the measured particle concentration change ⁇ ⁇ -? is confirmed.
  • the discrepancy A between the expected particle concentration change AT exp and the measured particle concentration change AT 12 is greater than any applicable limit An m .
  • the limit Ai im may e.g. be fixed in such a way that an applicably large discrepancy may be permitted in order to avoid giving rise unnecessarily to an alarm relating to the function of the PM sensor 213, since the particle concentration change which the PM sensor signal will indicate due to the additive may be difficult to predict with the desired accuracy.
  • the PM sensor 213 may be assumed to emit representative readings pertaining to the particulate matter in the exhaust stream, since the PM sensor 213 may be assumed to be located at a position where the PM signal varies in an expected manner and thus is likely also at the intended position in the exhaust system and thus carries out measurements of a representative exhaust stream.
  • the method resumes to step 401 in order to carry out a new determination of the function of the PM sensor 213 at the applicable time as per the above.
  • step 408 If, on the other hand, it is confirmed at step 408 that the discrepancy A is greater than the limit Ai lm , the method continues to step 408. At step 408, an error signal is generated as per the description above, and the method is completed at step 409.
  • a method is thus provided which may be used to confirm whether the PM sensor 213 emits a representative signal by confirming whether it is subjected to a representative exhaust stream, which is confirmed by confirming whether the emitted signal from the PM sensor 213 changes in the expected manner with a change in the supply of additives .
  • manipulating the function of the PM sensor 213 may thus be made by e.g. moving the PM sensor to a position outside the exhaust stream, alternatively by e.g. leading the exhaust stream past the PM sensor 213 discovered during the operation of the vehicle 100, since the PM sensor will not, in the event of such manipulation, show any change in the signal emitted compared to a correctly positioned PM sensor where there is a change in the supplied additives.
  • the invention thus reduces the possibilities of manipulating the aftertreatment system unnoticed.
  • particulate matter in the exhaust stream 200 may also vary significantly depending on other factors, such as the combustion engine's current operating parameters, where a measured single particle concentration change in unfavourable conditions may differ from the expected particle concentration change by more than the said discrepancy Ai ilT1 , even though the PM sensor 213 is correctly installed in the exhaust stream and subjected to a representative exhaust stream.
  • each method may be set up to be completed an applicable number of times x, e.g. a relatively big number of times x, where x measured values are confirmed, and thus x discrepancies A, where an overall integrated discrepancy for these x discrepancies may be determined and compared with the discrepancy limit Ai im , and where the overall integrated value is used to confirm whether the PM sensor 213 may be assumed to be subjected to a representative exhaust stream.
  • the discrepancy Ai im may also be set up to vary according to the number of measured values x. The greater the number of measured values x used, the lower the permitted discrepancy A n , may be set, since the overall integrated accuracy
  • a number of determinations are carried out instead, e.g. with regular or appropriate
  • the PM sensor 213 is placed in an exhaust gas composition, but also that the PM sensor 213 is arranged inside an exhaust stream whose
  • composition varies with the varying operational conditions in a representative manner.
  • determination according to the present invention is carried out regardless of the PM sensor's position in the exhaust system, as long as the change in additives supplied is made upstream of the PM sensor.
  • a frequency analysis is used to confirm whether the PM sensor 213 emits a representative signal.
  • This frequency analysis may be made with the help of an applicable transform, such as fourier transform, or FFT (Fast Fourier Transform) .
  • injection of additives is usually carried out with a certain frequency, such as a frequency in the interval 0.1-10 Hz. This means that the additive is "pulsated" into the exhaust stream, and pulselike differences will arise in the additive content of the exhaust stream over time. This also means that the pulsation will give rise to variations in concentration with the same frequency as for the additive, which is also used above, but which may be used in a way which ensures a more reliable detection.
  • the injection pulsation may be clarified and used according to the present invention.
  • the additive pulses will, according to the above, be visible as amplitude variations at a frequency which is equal to the injection frequency.
  • This frequency analysis may thus, at least in certain cases, be used to improve safety in the diagnosis of the PM sensor, since if this pulsation may be identified, it may then also be assumed that the PM sensor is subjected to a representative exhaust stream.
  • the frequency analysis may be used alone or in combination with a comparison against a limit as per the above, where this limit may be set in the time domain or the frequency domain.
  • variations i.e. a lower Ai im limit may be used. Variations in the frequency domain may also be used actively since the injection frequency, according to the method of the invention, may be varied to give a more reliable diagnosis. If e.g. An n , is exceeded for one injection frequency, a pending error may be set, so that one or more further diagnoses for further injection frequencies may be carried out before the malfunction is finally confirmed.
  • the result obtained from the analysis is more reliable the closer to the pulsation source the analysis is performed.
  • the said frequency analysis thus constitutes a representation of a change in the signal emitted by the said PM sensor 213.
  • PM sensors there are various types of PM sensors, and the present invention is applicable to all types of PM sensors which exhibit cross-sensitivity to additives.
  • IDE sensors where ceramic plates coated with conductive materials are used to confirm a particle content for a passing exhaust stream. As an exhaust stream containing particles passes the coated ceramic plates, particles will stick, which in turn entail that the
  • particle sensors such as electrostatic particle sensors, where particles pass by a first electrode to pick up a charge and then pass a second electrode set up in the particle sensor where the charge is delivered.
  • electrostatic particle sensors where particles pass by a first electrode to pick up a charge and then pass a second electrode set up in the particle sensor where the charge is delivered.
  • the number of electrons per time unit which is transmitted between the electrodes will thus vary, and therefore both the particle content and also the particle number may therefore be
  • this type of particle sensor is used to determine the concentration and/or fraction of particles in the exhaust stream. Thanks to the speed of the sensor, very good present value measurements may be made, i.e. very good values representing instantaneous particle content may be obtained.
  • the method according to the invention may be combined with the method described in the Swedish application No. 1250961-8 entitled "ME THOD AND SYSTEM PERTAINING TO
  • EXHAUST AFTERTREATMENT by the same inventor and with the same submission date as the present application, in order to establish a sensor function for a PM sensor.
  • a method is provided to establish whether a PM sensor emits a representative signal, where the sensor function for the PM sensor is established based on a
  • the present invention has been exemplified above in relation to vehicles.
  • the invention is, however, applicable to any vessels/processes where particulate filter systems, as per the above, are applicable, such as watercrafts and aircrafts with combustion processes as per the above.
  • combustion engine may e.g. consist of at least one of the group: automotive engine, marine engine, industrial engine, diesel engine, spark ignition engine, GDI engine, gas engine.

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

Abstract

La présente invention concerne un procédé pour établir une fonction de capteur pour un capteur PM (213) destiné à déterminer une teneur en particules dans un flux de gaz d'échappement résultant de la combustion dans un moteur à combustion (101), un système de post-traitement (200) étant installé pour le post-traitement dudit flux de gaz d'échappement. Ledit véhicule comprend un élément pour l'alimentation dudit flux de gaz d'échappement en additifs. Le procédé comprend : - l'établissement d'un changement du signal émis par ledit capteur PM (213) en réponse à un changement de l'alimentation en additifs, et - sur la base dudit changement dudit signal émis par ledit capteur PM, le fait de déterminer si ledit capteur PM (213) émet un signal représentant ledit flux de gaz d'échappement. La présente invention a également trait à un système et à un véhicule.
PCT/SE2013/051006 2012-08-30 2013-08-28 Procédé et système pour établir une fonction de capteur pour un capteur pm dans un flux de gaz d'échappement WO2014035324A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE112013003883.8T DE112013003883B4 (de) 2012-08-30 2013-08-28 Verfahren und System zum Feststellen einer Sensorfunktion für einen PM-Sensor in einem Abgasstrom

Applications Claiming Priority (2)

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SE1250966-7 2012-08-30
SE1250966A SE537009C2 (sv) 2012-08-30 2012-08-30 Förfarande och system för att fastställa en sensorfunktion hos en PM-sensor

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WO2014035324A1 true WO2014035324A1 (fr) 2014-03-06

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DE (1) DE112013003883B4 (fr)
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Citations (5)

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US20090113983A1 (en) * 2007-11-05 2009-05-07 Honeywell International Inc. Particulate matter sensor electrodes with embedded self-calibrator, and methods using same
US20100049462A1 (en) * 2008-08-19 2010-02-25 Honeywell International Inc. Particulate matter sensor calibration
US20110163761A1 (en) * 2010-01-07 2011-07-07 Ngk Insulators, Ltd. Particulate matter detection device and inspection method of the particulate matter detection device
US20120031078A1 (en) * 2010-08-06 2012-02-09 Denso Corporation Sensor controller
US20120227377A1 (en) * 2011-03-08 2012-09-13 Ford Global Technologies, Llc Method for Diagnosing Operation of a Particulate Matter Sensor

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DE102009028953A1 (de) 2009-08-27 2011-03-03 Robert Bosch Gmbh Verfahren zum Ermitteln eines Maßes für das Auftreten von Reagenzmitteltropfen im Abgasbereich einer Brennkraftmaschine und Vorrichtung zur Durchführung des Verfahrens
DE102011006923A1 (de) 2011-04-07 2012-10-11 Robert Bosch Gmbh Vorrichtung und Verfahren zur Diagnose der Funktion eines Partikelsensors
SE536773C2 (sv) 2012-08-30 2014-07-29 Scania Cv Ab Förfarande och system för att baserat på temperaturjämförelser fastställa en sensorfunktion för en PM-sensor
SE536845C2 (sv) 2012-08-30 2014-09-30 Scania Cv Ab Förfarande och system för att med hjälp av koncentrations- och/eller fraktionsjämförelser fastställa en sensorfunktion för en PM-sensor
SE536774C2 (sv) 2012-08-30 2014-07-29 Scania Cv Ab Förfarande och system för att med hjälp av tryckjämförelserfastställa en sensorfunktion för en PM-sensor

Patent Citations (5)

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Publication number Priority date Publication date Assignee Title
US20090113983A1 (en) * 2007-11-05 2009-05-07 Honeywell International Inc. Particulate matter sensor electrodes with embedded self-calibrator, and methods using same
US20100049462A1 (en) * 2008-08-19 2010-02-25 Honeywell International Inc. Particulate matter sensor calibration
US20110163761A1 (en) * 2010-01-07 2011-07-07 Ngk Insulators, Ltd. Particulate matter detection device and inspection method of the particulate matter detection device
US20120031078A1 (en) * 2010-08-06 2012-02-09 Denso Corporation Sensor controller
US20120227377A1 (en) * 2011-03-08 2012-09-13 Ford Global Technologies, Llc Method for Diagnosing Operation of a Particulate Matter Sensor

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SE537009C2 (sv) 2014-12-02
SE1250966A1 (sv) 2014-03-01
DE112013003883T5 (de) 2015-05-21
DE112013003883B4 (de) 2018-09-20

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