WO2019102707A1 - 異常判定装置 - Google Patents

異常判定装置 Download PDF

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Publication number
WO2019102707A1
WO2019102707A1 PCT/JP2018/035470 JP2018035470W WO2019102707A1 WO 2019102707 A1 WO2019102707 A1 WO 2019102707A1 JP 2018035470 W JP2018035470 W JP 2018035470W WO 2019102707 A1 WO2019102707 A1 WO 2019102707A1
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WO
WIPO (PCT)
Prior art keywords
temperature
exhaust
abnormality
change
filter
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.)
Ceased
Application number
PCT/JP2018/035470
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English (en)
French (fr)
Japanese (ja)
Inventor
真吾 中田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Denso Corp
Original Assignee
Denso Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Denso Corp filed Critical Denso Corp
Priority to CN201880074736.XA priority Critical patent/CN111373127B/zh
Priority to DE112018005946.4T priority patent/DE112018005946T5/de
Publication of WO2019102707A1 publication Critical patent/WO2019102707A1/ja
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02—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
    • 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
    • F01N11/002—Monitoring or diagnostic devices for exhaust-gas treatment apparatus 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
    • F01N2430/00—Influencing exhaust purification, e.g. starting of catalytic reaction, filter regeneration, or the like, by controlling engine operating characteristics
    • 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
    • F01N2560/06—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
    • F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/06—Parameters used for exhaust control or diagnosing
    • F01N2900/08—Parameters used for exhaust control or diagnosing said parameters being related to the engine
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
    • F01N2900/06—Parameters used for exhaust control or diagnosing
    • F01N2900/14—Parameters used for exhaust control or diagnosing said parameters being related to the exhaust gas
    • F01N2900/1404—Exhaust gas temperature
    • 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
    • F02D41/04—Introducing corrections for particular operating conditions
    • F02D41/06—Introducing corrections for particular operating conditions for engine starting or warming up
    • F02D41/062—Introducing corrections for particular operating conditions for engine starting or warming up for starting
    • F02D41/064—Introducing corrections for particular operating conditions for engine starting or warming up for starting at cold start
    • 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
    • F02D41/1446—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 exhaust temperatures
    • 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 disclosure described in the present specification relates to an abnormality determination device that determines an abnormality in a particulate filter.
  • a particulate filter abnormality determining method is known.
  • the particulate filter is provided in the exhaust passage.
  • An upstream exhaust temperature sensor is disposed in the exhaust passage upstream of the particulate filter.
  • a downstream exhaust temperature sensor is disposed in the exhaust passage downstream of the particulate filter. Output signals of the upstream exhaust temperature sensor and the downstream exhaust temperature sensor are input to the ECU.
  • the ECU detects an abnormality of the particulate filter based on the input output signal.
  • the upstream side exhaust temperature sensor and the downstream side exhaust temperature sensor are required to detect the abnormality of the particulate filter. Therefore, there was an issue that the number of parts was large.
  • an object of the disclosure described in the present specification is to provide an abnormality determination device capable of detecting an abnormality in a particulate filter while suppressing an increase in the number of parts.
  • An abnormality determination device includes an exhaust gas temperature sensor for detecting the temperature of exhaust gas provided downstream of a particulate filter provided in an exhaust gas passage through which exhaust gas from a gasoline engine is discharged; A determination unit that determines an abnormality of the particulate filter based on a change in output of the exhaust gas temperature sensor at the time of change in operation of the gasoline engine in which a change occurs in the temperature of the exhaust gas discharged.
  • the output of the exhaust temperature sensor provided on the downstream side of the particulate filter is changed behind the change of the operating condition of the gasoline engine.
  • the particulate filter is not attached to the exhaust passage or a defect such as a hole occurs, heat transfer between the particulate filter and the exhaust gas does not occur or decreases. Therefore, the output of the exhaust temperature sensor changes following the change in the operating condition of the gasoline engine without delay as compared with the case where the particulate filter is normally attached to the exhaust passage.
  • the abnormality of the particulate filter can be determined based on the change in the output of the exhaust gas temperature sensor at the time of the change in the operation of the gasoline engine which causes the temperature change of the exhaust gas in the exhaust passage as described above.
  • FIG. 1 is a schematic view for explaining a combustion system
  • FIG. 2 is a timing chart for explaining the time change of the detected temperature
  • FIG. 3 is a flowchart for explaining abnormality determination of the particulate filter.
  • FIG. 4 is a flowchart for explaining the abnormality determination condition.
  • FIG. 5 is a flowchart for explaining the abnormality determination condition.
  • FIG. 6 is a flowchart for explaining the abnormality determination condition.
  • the combustion system 200 includes an abnormality determination device 100, an intake passage 110, an engine 120, an exhaust passage 130, a catalytic converter 140, and a PM filter 150.
  • Engine 120 corresponds to a gasoline engine.
  • PM filter is an abbreviation of particulate filter.
  • the engine 120 has a cylinder 121, a piston 122, an intake valve 123, an injector 124, an exhaust valve 125, and a spark plug 126.
  • a piston 122 is provided in the cylinder 121.
  • the combustion chamber 120 a is divided by the cylinder 121 and the piston 122.
  • the piston 122 reciprocates up and down in the cylinder 121.
  • the cylinder 121 is formed with an opening for communicating the combustion chamber 120 a with the intake port of the cylinder head.
  • An intake valve 123 is provided at this opening.
  • an intake pipe in which an intake passage 110 is formed therein is connected to an intake port via an intake manifold.
  • the communication between the combustion chamber 120 a and the intake port is controlled by the drive of the intake valve 123.
  • a throttle valve 111 is provided in the intake passage 110 located upstream of the intake port. By adjusting the opening degree of the throttle valve 111, the amount of gas in the intake passage 110 taken into the engine 120 from the intake passage 110 is adjusted.
  • the injector 124 injects a mist of gasoline fuel into the combustion chamber 120a.
  • the injection of gasoline fuel from the injector 124 to the combustion chamber 120a is performed within the period from the start of the intake stroke to the end of the compression stroke. As a result, a mixed gas of the gas of the intake passage 110 and the gasoline fuel is formed in the combustion chamber 120a.
  • the cylinder 121 is formed with an opening for communicating the combustion chamber 120 a with the exhaust port of the engine head.
  • An exhaust valve 125 is provided at this opening.
  • An exhaust pipe in which an exhaust passage 130 is formed is connected to an exhaust port via an exhaust manifold.
  • the communication between the combustion chamber 120 a and the exhaust port is controlled by driving the exhaust valve 125.
  • the spark plug 126 generates spark discharge in the combustion chamber 120a.
  • the spark discharge in the spark plug 126 occurs when the mixed gas in the combustion chamber 120 a is compressed and the piston 122 is located near the top dead center of the cylinder 121. Thereby, the mixed gas of the combustion chamber 120a burns.
  • the mixed gas in the combustion chamber 120a expands, whereby the piston 122 descends.
  • the kinetic energy of the piston 122 due to this combustion is converted to rotational energy of the crankshaft.
  • the rotational energy of the crankshaft is output to a drive wheel or the like through the power transmission device.
  • the exhaust valve 125 causes the combustion chamber 120a to communicate with the exhaust port.
  • the exhaust gas generated by the combustion of the mixed gas is discharged from the combustion chamber 120a to the exhaust port.
  • the exhaust gas is discharged to the exhaust passage 130 through the exhaust manifold.
  • a catalytic converter 140 and a PM filter 150 are provided in the exhaust passage 130. Assuming that the combustion chamber 120 a side of the exhaust passage 130 is upstream and the opposite side is downstream, the catalytic converter 140 is provided upstream of the PM filter 150.
  • the exhaust gas contains nitrogen oxides, carbon monoxide and hydrocarbons.
  • the catalytic converter 140 functions to convert these three air pollutants into nitrogen, carbon dioxide and water.
  • the exhaust gas also contains particulate matter.
  • the PM filter 150 functions to remove this particulate matter.
  • Catalytic converter 140 can not fully exhibit its function unless the temperature is high to a certain extent. Therefore, catalytic converter 140 is warmed up by combustion drive of engine 120 when engine 120 is started as described later. When the catalyst is applied to the PM filter 150, the catalyst is also warmed up by the combustion drive of the engine 120.
  • the combustion system 200 also includes a sensor 160 that detects various physical quantities.
  • a sensor 160 that detects various physical quantities.
  • this sensor 160 for example, there are a rotation angle sensor 161, a water temperature sensor 162, an air-fuel ratio sensor 163, a flow rate sensor 164, a pressure sensor 165, and an exhaust temperature sensor 166 shown in FIG.
  • a throttle opening sensor (not shown) which is different from the illustrated sensors.
  • a rotation angle sensor 161 shown in FIG. 1 detects the number of rotations of the engine 120.
  • a water temperature sensor 162 detects the temperature (cooling water temperature) of a refrigerant such as water that cools the engine 120.
  • the air-fuel ratio sensor 163 detects the air-fuel ratio of the exhaust gas.
  • the flow rate sensor 164 detects the amount of gas in the intake passage 110 sucked into the combustion chamber 120a.
  • the pressure sensor 165 detects the pressure of the exhaust gas.
  • An exhaust temperature sensor 166 detects the temperature of the exhaust gas. The exhaust temperature sensor 166 is also included in the abnormality determination device 100 as described later.
  • the abnormality determination device 100 includes the ECU 10 and the exhaust gas temperature sensor 166 described above.
  • the ECU 10 has a microcomputer and a memory.
  • a detection signal of a sensor 160 including an exhaust temperature sensor 166 is input to the ECU 10.
  • the ECU 10 is electrically connected to another in-vehicle ECU via a wiring (not shown).
  • a signal is also input to the ECU 10 from the in-vehicle ECU.
  • the ECU 10 controls the drive of the engine 120 based on the detection signals of these sensors and the signals input from the on-vehicle ECU.
  • the ECU 10 also plays a role in detecting an abnormality of the PM filter 150.
  • the exhaust temperature sensor 166 is provided on the downstream side of the PM filter 150 in the exhaust passage 130. Therefore, the exhaust temperature sensor 166 detects the temperature change of the exhaust gas on the downstream side of the PM filter 150.
  • the ECU 10 corresponds to a determination unit.
  • the ECU that controls the engine 120 and the ECU that detects an abnormality in the PM filter 150 may be separate units.
  • the abnormality of the PM filter 150 can be determined based on the output change of the exhaust gas temperature sensor 166 downstream of the PM filter 150 when the operation of the engine 120 changes due to the temperature change of the exhaust gas in the exhaust passage 130.
  • the operation change of the engine 120 which causes the temperature change of the exhaust gas of the exhaust passage 130 largely occurs, for example, at the following three times. That is, at the time of cold start, sudden transition, and fuel cut, a large temperature change of the exhaust gas in the exhaust passage 130 occurs.
  • the cold start is at the start of the engine 120 and the cooling water temperature is not so high.
  • the sudden transition is when the rotational speed of the engine 120 changes rapidly.
  • the fuel cut time is when the supply of gasoline fuel to the engine 120 is stopped.
  • the temperature of the PM filter 150 is approximately the ambient temperature. Therefore, when the engine 120 starts and exhausts exhaust gas to the exhaust port, the temperature of each portion of the exhaust port and the exhaust passage 130 downstream of the exhaust port increases by receiving heat from the exhaust gas. Immediately after the cold start, the temperature difference between the PM filter 150 and the exhaust gas is large. Therefore, when the exhaust gas flows into the PM filter 150, much heat of the exhaust gas is consumed to heat the PM filter 150 by heat transfer. The heat transfer from the exhaust gas to the PM filter 150 is continued until the temperature of the PM filter 150 rises near the temperature of the exhaust gas. Due to the heat transfer, the temperature change of the exhaust gas after passing through the PM filter 150 becomes gentle with respect to the temperature change of the exhaust gas flowing into the PM filter 150.
  • the abnormality of the PM filter 150 can be determined based on the temperature rise of the temperature (detected temperature) detected by the exhaust temperature sensor 166.
  • the delay in tracking the temperature of the exhaust gas downstream of the PM filter 150 due to the heat transfer between the PM filter 150 and the exhaust gas is the PM filter as well as the temperature difference between the PM filter 150 and the exhaust gas flowing into it immediately after cold start. It also depends on the heat capacity of 150 and the pressure loss coefficient.
  • the time change of the detected temperature also depends on the wall constituting the exhaust passage 130 upstream of the PM filter 150 and the heat capacity and pressure loss coefficient of the catalytic converter 140.
  • the temperature of the exhaust gas discharged from the engine 120 to the exhaust port rapidly increases and decreases. Therefore, the temperature difference between the PM filter 150 and the exhaust gas flowing into the PM filter 150 becomes large, and heat transfer occurs between the exhaust gas and the PM filter 150. Therefore, when the PM filter 150 is normally attached to the exhaust passage 130 downstream of the exhaust port, the temperature change of the exhaust gas downstream of the PM filter 150 is slower than when the PM filter 150 is not properly attached. There is expected. Thus, the abnormality of the PM filter 150 can be determined based on the change in the detected temperature.
  • the abnormality of the PM filter 150 can be determined based on the specific temperature decrease of the detected temperature.
  • the temperature change of the exhaust gas largely occurs also when, for example, the intake amount (load) of the gas of the intake passage 110 to the combustion chamber 120a, the ignition timing, the air fuel ratio, etc. change rapidly.
  • the abnormality of the PM filter 150 can also be determined based on the temperature change of the exhaust gas downstream of the PM filter 150 at the time of the change of these operating conditions.
  • the above-mentioned fuel cut flag is referred to as an F / C flag in order to simplify the notation.
  • the air-fuel ratio is indicated as A / F.
  • the exhaust gas temperature immediately below the exhaust valve 125 is referred to as the most upstream exhaust temperature.
  • the detected temperature when the PM filter 150 is normal is indicated as the filter normal detected temperature.
  • the detected temperature when the PM filter 150 is abnormal is referred to as a filter abnormal detection temperature. The same applies to the drawings.
  • the F / C flag is included in the volatile memory of the ECU 10.
  • the most upstream exhaust temperature is the temperature on the most upstream side of the exhaust port and can be estimated based on the engine speed and the amount of gas in the intake passage 110 sucked into the combustion chamber 120a.
  • the most upstream exhaust temperature is estimated by the ECU 10.
  • the most upstream exhaust temperature corresponds to the temperature on the upstream side of the particulate filter.
  • the filter normal detection temperature exhibits a gradual behavior of temperature change compared to the uppermost stream exhaust temperature because of heat transfer between the PM filter 150 and the exhaust gas.
  • the temperature change of the filter abnormality detection temperature is steeper than the filter normal detection temperature. The filter abnormal detection temperature becomes close to the change behavior of the most upstream exhaust temperature.
  • a threshold value for determining a time of a sudden transition at the time of cold start of the engine 120 is stored. That is, as a threshold for determining the cold start time, a cold threshold to be compared with the cooling water temperature is stored in the non-volatile memory. As a threshold value for determining a sudden transition time, a sudden transient threshold value to be compared with a time change of the engine speed is stored in the non-volatile memory. Then, a fuel cut threshold value is stored in the non-volatile memory to determine whether the fuel cut is continued for a time suitable for determining the abnormality of the PM filter 150.
  • the cold threshold corresponds to the temperature threshold.
  • the sudden transient threshold corresponds to the rotation speed threshold.
  • the fuel cut threshold corresponds to the time threshold.
  • the non-volatile memory of the ECU 10 of the present embodiment stores an acceleration diagnostic temperature and a deceleration diagnostic temperature for determining whether a temperature change suitable for determining an abnormality of the PM filter 150 can be obtained. ing.
  • the acceleration diagnosis temperature corresponds to the first temperature.
  • the deceleration diagnosis temperature corresponds to the second temperature.
  • the acceleration diagnosis temperature is a value for determining whether or not the temperature change can be largely observed at the time of acceleration of the vehicle.
  • the ECU 10 determines that it is suitable for determining the abnormality of the PM filter 150.
  • the deceleration-time diagnostic temperature is a value for determining whether or not the temperature change can be largely observed when the vehicle is decelerating.
  • the ECU 10 determines that it is suitable for determining the abnormality of the PM filter 150.
  • the ECU 10 performs fuel cut at the time of deceleration. Therefore, the ECU 10 compares the diagnosis temperature at deceleration and the most upstream exhaust temperature at the time of fuel cut.
  • the ECU 10 of the present embodiment does not determine whether it is a sudden transition or not at the time of deceleration.
  • the ECU 10 determines whether or not it is a sudden transition time during acceleration. Then, the ECU 10 compares the acceleration diagnosis temperature with the most upstream exhaust temperature during this rapid transition.
  • the ECU 10 may determine whether it is a sudden transition time or not.
  • the ECU 10 compares the cooling water temperature with the cold threshold at the time of cold start. Therefore, the ECU 10 does not compare the diagnosis temperature with the most upstream exhaust temperature at cold start.
  • the change in the operation of the engine 120 and the change in the detected temperature of the exhaust temperature sensor 166 will be specifically described.
  • the vehicle speed is zero.
  • the engine speed is zero.
  • the cooling water temperature is about the ambient temperature.
  • the F / C flag is off.
  • a / F indicates lean.
  • the most upstream exhaust temperature is not estimated.
  • the filter normal detection temperature and the filter abnormality detection temperature are respectively the ambient temperature.
  • the ECU 10 is in an activated state.
  • the ECU 10 acquires detection signals of each sensor.
  • the ECU 10 communicates information with the in-vehicle ECU.
  • cranking increases the engine speed.
  • the engine 120 starts to burn and drive.
  • the coolant temperature starts to rise.
  • Exhaust gas begins to be discharged to the exhaust port and the exhaust passage 130 downstream thereof.
  • a / F becomes stoichiometric.
  • the catalytic converter 140 starts to be warmed up. Then, the ECU 10 starts to estimate the most upstream exhaust temperature.
  • the ECU 10 determines that the cold start is being performed.
  • the temperature at which the filter is normally detected is raised more slowly than the temperature at which the filter is abnormally detected because of heat transfer between the PM filter 150 and the exhaust gas.
  • the temperature at which the filter is abnormal is gradually raised compared to the most upstream exhaust temperature due to heat transfer between the exhaust gas and the wall constituting the exhaust passage 130, the catalytic converter 140, the PM filter 150, and the like.
  • the temperature at the time of the filter abnormality detection at this time is closer to the change behavior of the most upstream exhaust temperature, as compared with the abnormality at the time when a hole or the like is formed in the PM filter 150.
  • the ECU 10 determines that the cold start has ended.
  • the temperature of the exhaust gas in the exhaust passage 130 continues to rise due to the exhaust gas being discharged. Therefore, the most upstream exhaust temperature, the filter normal detection temperature, and the filter abnormality detection temperature continue to rise.
  • the temperature change is the most upstream exhaust temperature, the filter abnormal detection temperature, and the filter normal detection temperature in order from the largest one.
  • the vehicle speed increases and the vehicle travels. Along with this, the engine speed increases.
  • the temperature change of each of the most upstream exhaust temperature, the filter normal detection temperature, and the filter abnormality detection temperature becomes sharp.
  • the time change of the engine speed at this time is lower than the sudden transition threshold. Therefore, the ECU 10 determines that the engine 120 is not in a sudden transition state. This increase in vehicle speed continues until time t4.
  • the vehicle speed decreases.
  • the engine speed decreases.
  • the most upstream exhaust temperature starts to fall accordingly.
  • the temperature at the time of the filter abnormality detection starts to drop slightly behind the most upstream exhaust temperature.
  • the filter normal temperature starts to fall behind the filter abnormal detection temperature.
  • the F / C flag is turned on.
  • the supply of gasoline fuel to the engine 120 is stopped and not supplied. This eliminates the exhaust of the burned exhaust gas.
  • a / F changes from stoichiometric to lean.
  • the temperature change of each of the most upstream exhaust temperature, the filter normal detection temperature, and the filter abnormality detection temperature rapidly changes.
  • the ECU 10 determines that the fuel cut is not suitable for the engine 120 to determine the abnormality of the PM filter 150.
  • the ECU 10 determines that it is not suitable for determining the abnormality of the PM filter 150.
  • the reduction of the vehicle speed continues until time t7.
  • the F / C flag is turned off after the time t7. Thereby, the supply of gasoline fuel to the engine 120 is resumed.
  • the vehicle speed rises sharply. Along with this, the engine speed also increases rapidly. In response to this, the most upstream exhaust temperature, the filter normal detection temperature, and the filter abnormality detection temperature are also raised. The time change of the engine speed at this time is higher than the sudden transition threshold. Therefore, the ECU 10 determines that the engine 120 is in a sudden transition state. The state where the engine 120 is in the rapid transition state is continued until time t10.
  • the ECU 10 determines that it is suitable to determine the abnormality of the PM filter 150 between time t9 and time t10.
  • the most upstream exhaust temperature rises with the increase of the engine speed.
  • the filter abnormality detection temperature rises slightly behind the most upstream exhaust temperature.
  • the filter normal temperature rises behind the filter abnormal detection temperature.
  • the vehicle speed becomes constant.
  • the temperature change of the most upstream exhaust temperature becomes almost constant.
  • the filter abnormality detection temperature is slightly delayed from the most upstream exhaust temperature, and the temperature change becomes almost constant.
  • the filter normal temperature lags behind the filter abnormal detection temperature, and the temperature change becomes constant.
  • the vehicle speed decreases and the F / C flag is turned on.
  • the fuel cut is continued, but the duration is longer than the fuel cut threshold.
  • the most upstream exhaust temperature is higher than the deceleration diagnostic temperature. Therefore, the ECU 10 determines that the fuel cut time is suitable for the engine 120 to determine the abnormality of the PM filter 150.
  • the most upstream exhaust temperature, the filter normal detection temperature, and the filter abnormality detection temperature are each lowered to near the ambient temperature. This fuel cut is continued until time t12.
  • the ECU 10 determines whether a condition for determining abnormality of the PM filter 150 is satisfied.
  • the abnormality determination condition is a flow shown in FIGS. 4 to 6 described later. If the abnormality determination condition is satisfied, the ECU 10 proceeds to S200. Conversely, when the abnormality determination condition is not satisfied, the ECU 10 repeats S100 and enters the standby state.
  • step S200 the ECU 10 acquires the downstream temperature of the PM filter 150 detected by the exhaust temperature sensor 166. At this time, the ECU 10 detects the output (detected temperature) of the exhaust gas temperature sensor 166 at each predetermined acquisition timing. Then, the ECU 10 proceeds to S300.
  • the ECU 10 calculates a time change (temperature change) of the exhaust temperature on the downstream side of the PM filter 150 based on the plurality of detected temperatures and the acquisition timing acquired in S200. Then, the ECU 10 compares the calculated temperature change with the determination threshold value read out under the abnormality determination condition of S100 described later in detail. If the temperature change is faster than the determination threshold, the ECU 10 proceeds to S400. If the temperature change is equal to or less than the determination threshold, the ECU 10 proceeds to S500.
  • a time change temperature change of the exhaust temperature on the downstream side of the PM filter 150 based on the plurality of detected temperatures and the acquisition timing acquired in S200. Then, the ECU 10 compares the calculated temperature change with the determination threshold value read out under the abnormality determination condition of S100 described later in detail. If the temperature change is faster than the determination threshold, the ECU 10 proceeds to S400. If the temperature change is equal to or less than the determination threshold, the ECU 10 proceeds to S500.
  • the ECU 10 determines that the PM filter 150 is abnormal. In this case, the ECU 10 notifies an abnormality of the PM filter 150 to the user on board the vehicle by lighting an indicator or the like mounted on the vehicle. Unlike this, when the process proceeds to S500, the ECU 10 determines that the PM filter 150 is normal. Then, the ECU 10 ends the abnormality determination of the PM filter 150.
  • FIG. 4 is a flow of determining whether or not cold start is in progress.
  • FIG. 5 is a sudden transition time, and is a flow for determining whether the exhaust gas at the exhaust port (exhaust passage 130) is at a suitable temperature for determining the abnormality of the PM filter 150.
  • FIG. 6 shows a flow at the time of fuel cut, and at the same time, it is a flow to determine whether the exhaust gas of the exhaust port (exhaust passage 130) has a suitable temperature for determining the abnormality of the PM filter 150.
  • the ECU 10 processes these three abnormality determination conditions in parallel in S100. These three abnormality determination conditions are implemented during cold start, acceleration, and deceleration of the vehicle. Therefore, two or more of these three abnormality determination conditions are not satisfied at the same time.
  • the ECU 10 stores a determination threshold for determining an abnormality of the PM filter 150 in the non-volatile memory.
  • determination thresholds corresponding to each of cold start, sudden transition, and fuel cut are individually stored.
  • these three determination thresholds are different values. However, these three determination thresholds may be uniformly set to the same value. Alternatively, three determination threshold values may be defined by multiplying a certain reference value by a coefficient corresponding to each of the three abnormality determination conditions.
  • the ECU 10 determines whether the engine 120 has been started to start combustion drive. If it is determined that the engine 120 has been started, the ECU 10 proceeds to S11. Conversely, if it is determined that the engine 120 has not been started, the ECU 10 repeats S10 and enters the standby state.
  • the ECU 10 determines whether it is within a predetermined time after the engine 120 is started.
  • the predetermined time can be set as appropriate by the user. For example, several seconds, such as 2 seconds, can be employed as the predetermined time. If it is within a predetermined time after the engine 120 is started, the ECU 10 proceeds to S12. If a predetermined time has elapsed since the engine 120 was started, the ECU 10 returns to S10.
  • the ECU 10 determines whether the cooling water temperature is equal to or less than the cold threshold.
  • the cold threshold can be set by the user as appropriate. For example, as the cold threshold, a temperature slightly higher than the ambient temperature such as 40 ° C. can be employed. If the cooling water temperature is equal to or less than the cold threshold value, the ECU 10 proceeds to S13. If a predetermined time has elapsed since the engine 120 was started, the ECU 10 returns to S10.
  • ECU10 will determine with it being in a cold start. Then, the ECU 10 reads the determination threshold at the time of cold start from the non-volatile memory. After this, the ECU 10 proceeds to S200.
  • the determination threshold can be determined based on the temperature change of the PM filter 150 when the catalytic converter 140 is warmed up. Therefore, the determination threshold depends on the heat capacity of the PM filter 150.
  • this determination threshold can be determined by multiplying this by a coefficient such as 0.7.
  • the determination threshold in this case is 7.9 ° C./sec. This determination threshold corresponds to the follow-up threshold.
  • a coefficient is used to determine the determination threshold.
  • the values of these coefficients can be set as appropriate by experiments or simulations.
  • the ECU 10 determines whether the engine 120 is in the combustion driving state. If the engine 120 is in the combustion drive state, the ECU 10 proceeds to S31. On the contrary, when the engine 120 is not driven to burn, the ECU 10 repeats S30 to be in the standby state.
  • the ECU 10 determines whether the time change at the time of the increase of the engine speed is equal to or more than the rapid transition threshold.
  • the sudden transition threshold can be set as appropriate by the user. For example, several tens of rpm / sec such as 16 rpm / sec can be adopted as the rapid transient threshold. If the engine speed is equal to or higher than the rapid transition threshold, the ECU 10 proceeds to S32. If the engine speed is lower than the rapid transient threshold, the ECU 10 returns to S30.
  • the ECU 10 estimates the most upstream exhaust temperature when the engine speed becomes equal to or higher than the rapid transient threshold value based on the detection signals of the rotation angle sensor 161 and the flow rate sensor 164. Then, the ECU 10 proceeds to S33.
  • the ECU 10 determines whether the most upstream exhaust temperature is less than or equal to the acceleration diagnosis temperature.
  • the acceleration diagnosis temperature can be set as appropriate by the user. For example, 400 ° C. or the like can be adopted as the diagnosis temperature during acceleration. If the most upstream exhaust temperature is equal to or lower than the acceleration diagnosis temperature, the ECU 10 proceeds to S34. If the most upstream exhaust gas temperature is higher than the acceleration diagnosis temperature, the ECU 10 returns to S30.
  • step S34 the ECU 10 determines that the temperature is a sudden transition, and that the exhaust gas at the exhaust port (exhaust passage 130) has a suitable temperature for determining the abnormality of the PM filter 150. Then, the ECU 10 reads the determination threshold at the time of sudden transition from the non-volatile memory. After this, the ECU 10 proceeds to S200.
  • This determination threshold is the sudden transition threshold used in S31 with the temporal change in engine speed, and the uppermost exhaust temperature in the case of the acceleration diagnostic temperature used in S33. It can be determined on the basis of
  • the time change of the most upstream exhaust temperature at this time is, for example, 2.8 ° C./sec.
  • the determination threshold can be determined by multiplying this by a factor such as 0.7.
  • the determination threshold in this case is 1.96 ° C./sec.
  • this determination threshold may be determined based on the temperature change on the downstream side of the PM filter 150, which depends on the heat capacity of the PM filter 150, not on the time change of the most upstream exhaust temperature.
  • the temperature change on the downstream side is 1.1 ° C./sec.
  • the determination threshold can be determined by multiplying this by a factor such as 1.7.
  • the determination threshold in this case is 1.87 ° C./sec.
  • this judgment threshold can be set appropriately between 2.8 ° C./sec and 1.1 ° C./sec.
  • the determination threshold 1.9 ° C./sec between them can be adopted.
  • the ECU 10 determines whether the F / C flag is on. If the F / C flag is on, the ECU 10 proceeds to S51. Conversely, when the F / C flag is off, the ECU 10 repeats S50 and enters the standby state.
  • the ECU 10 estimates the most upstream exhaust temperature when the F / C flag is turned on, based on the detection signals of the rotation angle sensor 161 and the flow rate sensor 164. Then, the ECU 10 proceeds to S52.
  • the ECU 10 determines whether the most upstream exhaust temperature is equal to or higher than the deceleration diagnosis temperature.
  • the deceleration diagnosis temperature can be set as appropriate by the user. For example, the diagnosis temperature during deceleration can be 660.degree. If the most upstream exhaust gas temperature is equal to or higher than the deceleration diagnosis temperature, the ECU 10 proceeds to S53. If the most upstream exhaust temperature is lower than the deceleration diagnosis temperature, the ECU 10 returns to S50.
  • step S53 the ECU 10 determines whether the on time of the F / C flag is equal to or greater than the fuel cut threshold.
  • the fuel cut threshold can be set as appropriate by the user. For example, the fuel cut threshold may be several tens of seconds, such as 19 seconds. If the on time of the F / C flag is equal to or greater than the fuel cut threshold, the ECU 10 proceeds to S54. If the on time of the F / C flag is less than the fuel cut threshold, the ECU 10 returns to S50.
  • step S54 the ECU 10 determines that the temperature of the exhaust gas at the exhaust port (exhaust passage 130) is suitable for determining that the PM filter 150 is abnormal, at the time of fuel cut. Then, the ECU 10 reads out the determination threshold at the time of fuel cut from the non-volatile memory. After this, the ECU 10 proceeds to S200.
  • This determination threshold is the fuel cut threshold value used in S51 for the on time of the F / C flag, and the time change of the most upstream exhaust temperature when the most upstream exhaust temperature is about the deceleration diagnostic temperature used in S52 It can be determined based on
  • the time change of the most upstream exhaust gas temperature at this time is, for example, ⁇ 6.0 ° C./sec.
  • the determination threshold can be determined by multiplying this by a factor such as 0.7.
  • the determination threshold in this case is ⁇ 4.2 ° C./sec.
  • the above determination threshold may be determined based on the temperature change on the downstream side of the PM filter 150, which depends on the heat capacity of the PM filter 150, not on the time change of the most upstream exhaust temperature. Under the above conditions, when the PM filter 150 is normally provided in the exhaust passage 130, the temperature change on the downstream side is ⁇ 3.0 ° C./sec.
  • the determination threshold can be determined by multiplying this by a factor such as 1.6.
  • the determination threshold in this case is ⁇ 4.8 ° C./sec.
  • the determination threshold can be set appropriately as long as it is between ⁇ 6.0 ° C./sec and ⁇ 3.0 ° C./sec.
  • the judgment threshold can adopt -4.5 ° C / sec between them.
  • the operation and effect of the abnormality determination device 100 will be described.
  • the change in the output of the exhaust temperature sensor 166 at the time of the change in the operation of the engine 120 is, for example, when the PM filter 150 is properly attached to the exhaust passage 130 or not attached. It differs depending on whether or not an abnormality has occurred. Therefore, the abnormality of the PM filter 150 can be determined based on the outputs of various sensors originally mounted on the vehicle and the output change of the exhaust gas temperature sensor 166 provided downstream of the PM filter 150.
  • an abnormality of the PM filter 150 can be determined. This suppresses an increase in the number of parts. In addition, the increase in product cost is also suppressed.
  • the ECU 10 detects a change in output of the exhaust temperature sensor 166 at the time of cold start, at which the temperature change of the exhaust passage 130 largely changes, at a time of a sudden transition, and at the time of fuel cut.
  • the change in the output of the exhaust gas temperature sensor 166 is suppressed from being reduced.
  • the reduction in the accuracy of determination of abnormality of the PM filter 150 is suppressed.
  • the ECU 10 detects a change in the output of the exhaust gas temperature sensor 166 when the most upstream exhaust gas temperature is equal to or lower than the acceleration diagnosis temperature at the time of rapid transition when the vehicle speed increases. Further, the ECU 10 detects a change in the output of the exhaust gas temperature sensor 166 when the fuel cut time at which the vehicle speed decreases decreases the continuation time thereof to the fuel threshold or more and the most upstream exhaust temperature is equal to or higher than the deceleration diagnosis temperature.
  • an example has been shown in which it is determined whether or not an abnormality of the PM filter 150 is determined at the time of fuel cut, based on the most upstream exhaust temperature and the on time of the F / C flag.
  • conditions may be further added, and after warm-up of catalytic converter 140, abnormality of PM filter 150 may be determined at the time of fuel cut based on the most upstream exhaust temperature and the on time of the F / C flag. .
  • the catalytic converter 140 also has a heat capacity. Therefore, when the warming up of catalytic converter 140 is not completed, catalytic converter 140 actively receives the heat of the exhaust gas. As a result, the temperature change on the downstream side of the catalytic converter 140 may be gradual. That is, there is a possibility that the change in the output of the exhaust temperature sensor 166 may be gradual.
  • the 4th modification In the present embodiment, an example is shown in which one determination threshold for each abnormality determination condition is stored in the non-volatile memory. On the other hand, it is also possible to adopt a configuration in which a map for the determination threshold according to the engine speed and the intake amount (load) of the gas of the intake passage 110 to the combustion chamber 120a is stored in the non-volatile memory.
  • (Fifth modification) In the present embodiment, it is determined based on the time change of the engine speed whether or not it is a sudden transition time. However, unlike this, it may be determined based on the time change of the intake amount (load) of the gas of the intake passage 110 to the combustion chamber 120 a whether or not it is a sudden transition time.

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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)
  • Processes For Solid Components From Exhaust (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)
PCT/JP2018/035470 2017-11-22 2018-09-25 異常判定装置 Ceased WO2019102707A1 (ja)

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JP2008190538A (ja) * 2008-05-15 2008-08-21 Toyota Motor Corp パティキュレートフィルタ異常判定方法
JP2010112254A (ja) * 2008-11-06 2010-05-20 Toyota Motor Corp パティキュレートフィルタの異常判定システム

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JP4238788B2 (ja) * 2004-06-21 2009-03-18 トヨタ自動車株式会社 パティキュレートフィルタ異常判定方法
JP4985071B2 (ja) * 2007-04-13 2012-07-25 トヨタ自動車株式会社 内燃機関の排気浄化装置
JP5040958B2 (ja) * 2009-05-26 2012-10-03 トヨタ自動車株式会社 フィルタの故障検出システム

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Publication number Priority date Publication date Assignee Title
JP2008190538A (ja) * 2008-05-15 2008-08-21 Toyota Motor Corp パティキュレートフィルタ異常判定方法
JP2010112254A (ja) * 2008-11-06 2010-05-20 Toyota Motor Corp パティキュレートフィルタの異常判定システム

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