WO2012081094A1 - 電気加熱式触媒の故障検出装置 - Google Patents
電気加熱式触媒の故障検出装置 Download PDFInfo
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- WO2012081094A1 WO2012081094A1 PCT/JP2010/072560 JP2010072560W WO2012081094A1 WO 2012081094 A1 WO2012081094 A1 WO 2012081094A1 JP 2010072560 W JP2010072560 W JP 2010072560W WO 2012081094 A1 WO2012081094 A1 WO 2012081094A1
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- electrically heated
- catalyst
- heated catalyst
- fuel ratio
- air
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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
- F01N3/08—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
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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
- F01N3/08—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
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N11/00—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity
- F01N11/007—Monitoring or diagnostic devices for exhaust-gas treatment apparatus, e.g. for catalytic activity the diagnostic devices measuring oxygen or air concentration downstream of the exhaust apparatus
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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
- F01N3/08—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
- F01N3/2006—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating
- F01N3/2013—Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating using electric or magnetic heating means
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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
- F01N3/08—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
- F01N3/24—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 constructional aspects of converting apparatus
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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
- F01N9/00—Electrical control of exhaust gas treating apparatus
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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
- F01N9/00—Electrical control of exhaust gas treating apparatus
- F01N9/007—Storing data relevant to operation of exhaust systems for later retrieval and analysis, e.g. to research exhaust system malfunctions
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- 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
- F02D41/021—Introducing corrections for particular conditions exterior to the engine
- F02D41/0235—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
- F02D41/024—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to increase temperature of the exhaust gas treating apparatus
- F02D41/0255—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to increase temperature of the exhaust gas treating apparatus to accelerate the warming-up of the exhaust gas treating apparatus at engine start
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- 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
- F02D41/1473—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the regulation method
- F02D41/1474—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the regulation method by detecting the commutation time of the sensor
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- 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
- F02D41/221—Safety or indicating devices for abnormal conditions relating to the failure of actuators or electrically driven elements
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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
- F01N2550/00—Monitoring or diagnosing the deterioration of exhaust systems
- F01N2550/02—Catalytic activity of catalytic converters
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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
- F01N2550/00—Monitoring or diagnosing the deterioration of exhaust systems
- F01N2550/22—Monitoring or diagnosing the deterioration of exhaust systems of electric heaters for exhaust systems or their power supply
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D2200/00—Input parameters for engine control
- F02D2200/02—Input parameters for engine control the parameters being related to the engine
- F02D2200/08—Exhaust gas treatment apparatus parameters
- F02D2200/0802—Temperature of the exhaust gas treatment apparatus
- F02D2200/0804—Estimation of the temperature of the exhaust gas treatment apparatus
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- 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
- F02D41/1454—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 an oxygen content or concentration or the air-fuel ratio
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- 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
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/40—Engine management systems
Definitions
- the present invention relates to a failure detection device for an electrically heated catalyst.
- a technique is known in which a catalyst carrier having electrical resistance is energized to increase the temperature of the catalyst at the time of cold start of the internal combustion engine so as to activate the catalyst at an early stage (see, for example, Patent Document 1). Further, a technique for determining an abnormality of a catalyst based on an output value of an oxygen concentration sensor provided on the downstream side of the catalyst is known (for example, see Patent Document 2). Further, it is determined that the catalyst is activated when the reversal cycle of the rich / lean air-fuel ratio detected by the oxygen sensor provided on the downstream side of the catalyst exceeds a predetermined time. There is known a technique for estimating the amount of heat required until conversion and determining the deterioration of the catalyst according to the integrated value of the amount of heat (see, for example, Patent Document 3).
- the temperature of the electrically heated catalyst does not rise unless energized. For this reason, if the temperature of the electrically heated catalyst is known, it can be determined whether or not power is supplied, so that the failure of the electrically heated catalyst can be detected.
- a temperature sensor may be attached to the heating element.
- SiC used for a heating element of an electrically heated catalyst is hard and brittle. And it is difficult to embed a temperature sensor because it is difficult to expand. There is also a cost to process and add a temperature sensor.
- the present invention has been made in view of the above problems, and its purpose is to determine whether or not the electrically heated catalyst is normal by accurately detecting whether or not the temperature of the electrically heated catalyst has increased. Is to detect.
- An air-fuel ratio control device that makes the air-fuel ratio of the exhaust gas flowing into the electric heating catalyst when the internal combustion engine starts into a rich air-fuel ratio;
- a downstream side detection device that is provided downstream of the electrically heated catalyst and detects the oxygen concentration in the exhaust; The oxygen concentration detected by the downstream side detection device changes to a value indicating the rich air-fuel ratio after the internal combustion engine is started and when the air-fuel ratio of the exhaust gas is made rich by the air-fuel ratio control device.
- the air-fuel ratio control device only needs to set the air-fuel ratio of the exhaust to the rich air-fuel ratio in the period required for the determination by the determination device.
- the determination device may perform the determination only during a period in which the air-fuel ratio of the exhaust gas is set to the rich air-fuel ratio by the air-fuel ratio control device.
- the electrically heated catalyst fails and the temperature of the catalyst does not rise, oxygen is not stored in the catalyst, so oxygen is not released even if the air-fuel ratio of the exhaust gas passing through the catalyst becomes a rich air-fuel ratio. For this reason, the air-fuel ratio of the exhaust downstream of the electrically heated catalyst immediately becomes a rich air-fuel ratio.
- the timing when the oxygen concentration detected by the downstream side detection device changes to a value indicating the rich air-fuel ratio changes according to the temperature of the electrically heated catalyst. That is, it is possible to determine whether or not the temperature of the electrically heated catalyst is rising based on the timing when the oxygen concentration detected by the downstream side detection device changes to a value indicating a rich air-fuel ratio.
- the temperature of the electrically heated catalyst is increased, it is possible to determine that the electrically heated catalyst is normal because the electricity to the electrically heated catalyst is normally supplied. Even when the internal combustion engine is controlled to have a rich air-fuel ratio, the exhaust gas from the previous operation of the internal combustion engine remains in the exhaust passage before the internal combustion engine is started. For this reason, when the internal combustion engine is started, a gas containing a large amount of oxygen passes through the electrically heated catalyst. At this time, oxygen is stored in the catalyst.
- the determination device has a time from when the internal combustion engine is started to when the oxygen concentration detected by the downstream detection device changes to a value indicating a rich air-fuel ratio, When it is longer than a predetermined time, it is determined that the electric heating catalyst is normally energized, When the time is equal to or shorter than the predetermined time, it can be determined that the electric heating catalyst is not normally energized.
- the electrically heated catalyst is normal, oxygen is released from the catalyst when the rich air-fuel ratio exhaust gas passes, and therefore the period during which the downstream air-fuel ratio is substantially the stoichiometric air-fuel ratio is relatively long.
- the temperature of the electrically heated catalyst is not increased, oxygen is not released even if the rich air-fuel ratio exhaust gas passes, so the downstream air-fuel ratio becomes the same rich air-fuel ratio as the upstream side.
- the amount of increase in the temperature of the catalyst is not sufficient, the amount of oxygen stored is reduced by that amount. Therefore, when the rich air-fuel ratio exhaust gas passes through, the time for which the stoichiometric air-fuel ratio is substantially reduced on the downstream side is shortened.
- the time from when the internal combustion engine is started until the air-fuel ratio downstream of the catalyst becomes the rich air-fuel ratio has a correlation with the temperature of the catalyst. Based on this time, it can be determined whether or not the temperature of the catalyst has risen, so that a failure of the electrically heated catalyst can be detected.
- the predetermined time can be set as a threshold when the electric heating catalyst is in a boundary between when it is normal and when it is out of order.
- the determination device has a time from when the internal combustion engine is started until the oxygen concentration detected by the upstream side detection device and the downstream side detection device becomes a value indicating a rich air-fuel ratio. When it is longer than a predetermined time, it is determined that the electric heating catalyst is normally energized, When the time is equal to or shorter than the predetermined time, it can be determined that the electric heating catalyst is not normally energized.
- the electrically heated catalyst is normal, oxygen is released from the catalyst when the rich air-fuel ratio exhaust gas passes, so the air-fuel ratio upstream of the electrically heated catalyst is the rich air-fuel ratio.
- the period during which the downstream air-fuel ratio is substantially the stoichiometric air-fuel ratio is relatively long.
- the temperature of the electrically heated catalyst is not increased, oxygen is not released even when the rich air-fuel ratio exhaust gas passes, so the upstream air-fuel ratio and the downstream air-fuel ratio become the rich air-fuel ratio. Further, when the amount of increase in the temperature of the catalyst is not sufficient, the amount of oxygen stored is reduced by that amount.
- the time for which the stoichiometric air-fuel ratio is substantially reduced on the downstream side is shortened.
- the time from when the internal combustion engine is started until the oxygen concentration detected by the upstream side detection device and the downstream side detection device becomes a value indicating the rich air-fuel ratio is correlated with the temperature of the catalyst. That is, based on this time, it can be determined whether or not the temperature of the catalyst is rising, so that a failure of the electrically heated catalyst can be detected.
- the predetermined time can be set as a threshold value when the electric heating catalyst is in a boundary between when it is normal and when it is out of order.
- the time from when the oxygen concentration detected by the upstream side detection device becomes a value indicating the rich air-fuel ratio until the oxygen concentration detected by the downstream side detection device becomes a value indicating the rich air-fuel ratio is less than a predetermined time.
- the electric heating catalyst can be energized before the internal combustion engine is started.
- the electrically heated catalyst is normal, the temperature of the electrically heated catalyst is high when the internal combustion engine is started, and oxygen can be stored immediately. For this reason, the time required for failure detection can be shortened and the detection accuracy can be increased.
- a resistance detection device that detects an electric resistance of the electric heating catalyst when the electric heating catalyst is energized;
- An estimation device that estimates the temperature of the electrically heated catalyst based on the electrical resistance detected by the resistance detection device; With The determination device can determine whether the electric heating catalyst is energized when the temperature of the electric heating catalyst estimated by the estimation device is higher than a predetermined value.
- the temperature can be estimated based on the electric resistance.
- the temperature estimated in this way is low in accuracy, if the failure detection of the electrically heated catalyst is performed based on this temperature, the accuracy becomes low.
- an approximate temperature can be estimated.
- the energization may be stopped because there is no need for energization. After the energization is thus stopped, the temperature of the electrically heated catalyst gradually decreases. If the time until the internal combustion engine is started becomes long, the activity of the catalyst cannot be maintained due to a decrease in temperature.
- the temperature estimated by the estimation device is higher than a predetermined value as a precondition for detecting a failure of the electrically heated catalyst. That is, failure detection is performed only when the estimated temperature is higher than a predetermined value.
- the predetermined value may be an upper limit value of the temperature at which the catalyst is not activated. When the temperature of the catalyst exceeds this upper limit value, it is estimated that the catalyst is activated. Then, it is possible to further improve the detection accuracy by determining whether or not to perform failure detection based on the estimated temperature.
- a resistance detection device that detects an electric resistance of the electric heating catalyst when the electric heating catalyst is energized;
- An estimation device that estimates the temperature of the electrically heated catalyst based on the electrical resistance detected by the resistance detection device; With The determination device can determine that the electric heating catalyst is energized only when the temperature of the electric heating catalyst estimated by the estimation device is higher than a predetermined value.
- the detection accuracy can be further improved by performing the failure detection based on the estimated temperature and the oxygen concentration downstream of the electrically heated catalyst.
- the present invention it is possible to detect whether or not the electrically heated catalyst is normal by accurately detecting whether or not the temperature of the electrically heated catalyst has risen.
- 3 is a flowchart illustrating a failure determination flow of the electrically heated catalyst according to the first embodiment. It is the figure which showed the relationship between the electrical resistance when supplying with electricity to an electrically heated catalyst, and temperature.
- 3 is a flowchart illustrating a flow of a failure determination process using the oxygen sensor according to the first embodiment.
- 10 is a flowchart illustrating a flow of a failure determination process using an air-fuel ratio sensor and an oxygen sensor according to a second embodiment.
- 10 is a flowchart illustrating a temporary failure determination flow of the electrically heated catalyst according to the third embodiment. It is the flowchart which showed the flow of the temporary failure determination process. It is the flowchart which showed the flow of this failure determination process. It is another flowchart which showed the flow of this failure determination process.
- FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine and an electrically heated catalyst according to the present embodiment.
- the internal combustion engine 1 is mounted on a vehicle and may be a diesel engine or a gasoline engine.
- a hybrid system including the electric motor 2 may be employed.
- the electric motor 2 can rotate the crankshaft of the internal combustion engine 1 or drive the vehicle.
- the exhaust passage 3 is connected to the internal combustion engine 1.
- An electrically heated catalyst 4 is provided in the middle of the exhaust passage 3.
- An air-fuel ratio sensor 5 for measuring the air-fuel ratio of the exhaust gas flowing through the exhaust passage 3 is attached to the exhaust passage 3 upstream of the electrically heated catalyst 4.
- An oxygen sensor 6 for measuring the oxygen concentration of the exhaust gas flowing through the exhaust passage 3 is attached to the exhaust passage 3 downstream of the electrically heated catalyst 4.
- the air-fuel ratio sensor 5 outputs a signal corresponding to the air-fuel ratio of the exhaust. That is, according to the air-fuel ratio sensor 5, the value of the air-fuel ratio can be detected. Further, the output signal of the oxygen sensor 6 changes suddenly with the theoretical air-fuel ratio as a boundary.
- the oxygen sensor 6 can detect whether the air-fuel ratio of the exhaust is richer or leaner than the stoichiometric air-fuel ratio.
- the air-fuel ratio sensor 5 corresponds to the upstream side detection device in the present invention.
- the oxygen sensor 6 corresponds to the downstream side detection device in the present invention.
- the electrically heated catalyst 4 is configured to include a heating element and a catalyst.
- a heating element a material that generates heat when energized is used.
- SiC can be used as the material of the heating element.
- Two electrodes are connected to the heating element, and the heating element is energized by applying a voltage between the electrodes. The heating element generates heat due to the electrical resistance of the heating element.
- the catalyst is supported on this heating element, or the catalyst is provided on the downstream side of the heating element.
- the catalyst should just be provided in the range which can receive the heat from a heat generating body.
- the catalyst include an oxidation catalyst, a three-way catalyst, an occlusion reduction type NOx catalyst, and a selective reduction type NOx catalyst. These catalysts have the ability to store oxygen.
- the internal combustion engine 1 is provided with an ECU 10 that is an electronic control unit for controlling the internal combustion engine 1.
- the ECU 10 includes a ROM, a RAM, and the like that store various programs and maps in addition to the CPU, and controls the internal combustion engine 1 according to the operating conditions of the internal combustion engine 1 and the driver's request.
- the ECU 10 is connected to an air-fuel ratio sensor 5 and an oxygen sensor 6 via electric wiring, and output signals from these sensors are input to the ECU 10.
- the electrically heated catalyst 4 is connected to the ECU 10 via an electrical wiring, and the ECU 10 controls energization to the electrically heated catalyst 4.
- the ECU 10 detects a failure of the electrically heated catalyst 4. In this failure detection, it is determined that a failure has occurred when the electric heating catalyst 4 is not energized normally. In this embodiment, the determination is made based on the oxygen storage amount of the catalyst.
- the catalyst when the catalyst is activated, oxygen in the exhaust gas is stored in the catalyst. Therefore, if the electrically heated catalyst 4 is normal, the catalyst is activated by energization and oxygen is stored. On the other hand, if the electrically heated catalyst 4 fails and the temperature of the catalyst does not rise, the catalyst is not activated and oxygen is not stored. In this way, there is a difference in the oxygen storage amount of the catalyst between the case where the electrically heated catalyst 4 is normal and the case where it is broken. By detecting this difference, failure detection of the electrically heated catalyst 4 can be performed.
- the electrically heated catalyst 4 is energized so that the catalyst is activated. Thereafter, the internal combustion engine 1 is started. At this time, the fuel injection amount or the intake air amount is adjusted so that the internal combustion engine 1 is operated at a rich air-fuel ratio. If the time from when the internal combustion engine 1 is started until the output value of the oxygen sensor 6 shows a rich air-fuel ratio is longer than a predetermined time, it is determined that the electric heating catalyst 4 is normal, If this time is equal to or shorter than the predetermined time, it is determined that the electrically heated catalyst 4 has failed. This predetermined time can be obtained by experiments or the like.
- the ECU 10 that operates the internal combustion engine 1 at a rich air-fuel ratio by adjusting the fuel injection amount or the intake air amount when the internal combustion engine 1 is started corresponds to the air-fuel ratio control device in the present invention.
- oxygen is released from the catalyst when the air-fuel ratio of the exhaust gas flowing into the electrically heated catalyst 4 is a rich air-fuel ratio.
- This oxygen makes the air-fuel ratio of the exhaust gas substantially the stoichiometric air-fuel ratio. That is, the air-fuel ratio of the exhaust gas becomes the stoichiometric air-fuel ratio downstream of the electrically heated catalyst 4.
- the output value of the oxygen sensor 6 does not indicate a rich air-fuel ratio. Thereafter, when the release of oxygen stored in the catalyst is finished, the output value of the oxygen sensor 6 indicates a rich air-fuel ratio.
- the electrically heated catalyst 4 is normal, it takes a certain amount of time from when the internal combustion engine 1 is started until the output value of the oxygen sensor 6 shows a rich air-fuel ratio.
- the catalyst is not activated, oxygen is hardly released from the catalyst even if the air-fuel ratio of the exhaust gas flowing into the electrically heated catalyst 4 is a rich air-fuel ratio. For this reason, the air-fuel ratio of the exhaust downstream of the electrically heated catalyst 4 becomes a rich air-fuel ratio. Therefore, immediately after the internal combustion engine 1 is started, the output value of the oxygen sensor 6 shows a rich air-fuel ratio. Thus, if the electrically heated catalyst 4 is out of order, it will not take much time until the output value of the oxygen sensor 6 indicates a rich air-fuel ratio after the internal combustion engine 1 is started.
- the electric heating catalyst 4 is normally energized based on the time from when the internal combustion engine 1 is started until the output value of the oxygen sensor 6 indicates a rich air-fuel ratio. Can do. That is, failure detection of the electrically heated catalyst 4 can be performed.
- FIG. 2 is a flowchart showing a failure determination flow of the electrically heated catalyst 4 according to the present embodiment. This routine is executed every predetermined time by the ECU 10.
- step S101 it is determined whether or not the catalyst is normal. That is, when the catalyst is deteriorated, the oxygen storage capacity is lowered, so that it is difficult to determine whether or not the electric heating type catalyst 4 is normally energized. Therefore, in this step, it is determined whether or not the catalyst has an ability to store oxygen. Whether or not the catalyst is normal is determined at the time of the previous operation of the internal combustion engine 1, and this result is stored in the ECU 10. A known technique can be used to determine whether or not the catalyst is normal. If an affirmative determination is made in step S101, the process proceeds to step S102. If a negative determination is made, this routine is terminated because there is a possibility that failure detection of the electrically heated catalyst 4 cannot be accurately performed.
- step S102 it is determined whether failure detection of the electrically heated catalyst 4 is incomplete. If an affirmative determination is made in step S102, the process proceeds to step S103. If a negative determination is made, it is not necessary to detect a failure of the electrically heated catalyst 4, and this routine is ended.
- step S103 it is determined whether or not energization of the electrically heated catalyst 4 is completed.
- the electrically heated catalyst 4 is normal, it is determined whether or not electric power sufficient to activate the catalyst is supplied.
- the energization is completed when a predetermined time has elapsed from the start of energization. Further, energization may be completed when predetermined power is supplied.
- the temperature of the electrically heated catalyst 4 may be estimated by, for example, electrical resistance, and the energization may be completed when the temperature reaches a predetermined temperature. This temperature estimation will be described later. If an affirmative determination is made in step S103, the process proceeds to step S104, and if a negative determination is made, this routine is terminated because it is not possible to determine the failure of the electrically heated catalyst 4.
- step S104 it is determined whether there is a request for starting the internal combustion engine 1.
- the internal combustion engine 1 is started when a predetermined speed is reached. That is, in such a case, it is determined that there is a request for starting the internal combustion engine 1. In the case of a vehicle that runs only with the internal combustion engine 1, for example, it is determined that there is a request for starting the internal combustion engine 1 when a switch for starting the internal combustion engine 1 is turned on. If an affirmative determination is made in step S104, the process proceeds to step S105, and if a negative determination is made, the process proceeds to step S106.
- step S105 failure determination processing for the electrically heated catalyst 4 is performed. This determination will be described later.
- the ECU 10 that processes step S105 corresponds to the determination device in the present invention.
- step S106 the temperature of the electrically heated catalyst 4 is estimated.
- the temperature of the electrically heated catalyst 4 is estimated until a request for starting the internal combustion engine 1 is made. This estimation is performed based on, for example, the electrical resistance when the electrically heated catalyst 4 is energized. At this time, since the electric heating catalyst 4 is not energized, the electric heating catalyst 4 is energized in order to detect the electric resistance of the electric heating catalyst 4.
- FIG. 3 is a diagram showing the relationship between electrical resistance and temperature when the electrically heated catalyst 4 is energized.
- the temperature T can be estimated based on the electric resistance R when the electric heating catalyst 4 is energized.
- the relationship between the temperature and the electric resistance may vary depending on individual differences and aging of the electrically heated catalyst 4. If so, there may be a difference between the relationship stored in the ECU 10 and the actual relationship.
- FIG. 4 is a flowchart showing a flow of a failure determination process using the oxygen sensor 6 according to the first embodiment. This routine is executed in step S105.
- step S201 it is determined whether or not the temperature of the electrically heated catalyst 4 estimated in step S106 is higher than a predetermined value.
- the predetermined value here is an upper limit value of the temperature at which the catalyst is not activated. That is, the catalyst is said to be activated when the temperature of the catalyst exceeds this upper limit. Since it is determined in step S103 that energization has been completed, energization of the electrically heated catalyst 4 is not performed when this step is processed. Then, since the temperature of the catalyst is gradually lowered, there is a possibility that the temperature of the catalyst becomes lower than the activation temperature. Therefore, in this step, it is determined whether or not the catalyst is activated.
- step S201 When the temperature of the catalyst is low, failure detection is not performed because failure detection based on the oxygen storage amount is difficult. Since the estimated temperature is low in accuracy, it is not used for failure detection, but is used for determining whether or not a precondition for performing failure detection is satisfied. If an affirmative determination is made in step S201, the process proceeds to step S202. If a negative determination is made, failure detection of the electrically heated catalyst 4 cannot be performed, and thus this routine is terminated.
- step S202 it is determined whether or not a rich air-fuel ratio is detected by the oxygen sensor 6. That is, it is determined whether or not the output value of the oxygen sensor 6 indicates a rich air-fuel ratio. If an affirmative determination is made in step S202, the process proceeds to step S203, and if a negative determination is made, this routine is ended because oxygen is being released from the catalyst.
- step S203 the time from when the internal combustion engine 1 is started until the output value of the oxygen sensor 6 indicates a rich air-fuel ratio is measured. This time is counted by a timer built in the ECU 10.
- step S204 it is determined whether the time from when the internal combustion engine 1 is started until the output value of the oxygen sensor 6 indicates a rich air-fuel ratio is longer than a predetermined time.
- the predetermined time is an upper limit value of the time from when the internal combustion engine 1 is started when the electrically heated catalyst 4 is out of order until the output value of the oxygen sensor 6 indicates a rich air-fuel ratio. That is, if the electrically heated catalyst 4 is normal, the time taken for the output value of the oxygen sensor 6 to exhibit a rich air-fuel ratio becomes longer.
- step S204 determines whether the catalyst is activated, and thus the process proceeds to step S205 where it is determined that the electrically heated catalyst 4 is normal.
- step S204 determines whether the catalyst is activated, and the process proceeds to step S206, and it is determined that the electrically heated catalyst 4 has failed.
- the catalyst is activated based on the output value of the oxygen sensor 6. Therefore, since it can be determined whether or not the temperature of the electrically heated catalyst 4 has increased, it can be determined whether or not the electrically heated catalyst 4 is normal. Further, since the temperature of the electrically heated catalyst 4 is unlikely to change when the internal combustion engine 1 is started, the accuracy of failure detection can be improved by performing failure detection at this time.
- the electric heating catalyst 4 is energized before the internal combustion engine 1 is started. Instead, the electric heating catalyst 4 is energized after or simultaneously with the internal combustion engine 1 is started. May start. Since it takes time until the catalyst is activated after the electric heating type catalyst 4 is energized, if the electric heating type catalyst 4 is energized before the internal combustion engine 1 is started, the exhaust gas can be purified quickly. It becomes possible. Further, since the hybrid vehicle can run only by the electric motor 2 without operating the internal combustion engine 1, even when the electric heating catalyst 4 is energized before the internal combustion engine 1 is started, The motor 2 can travel.
- the oxygen sensor 6 is heated before the internal combustion engine 1 is started in the same manner as the electrically heated catalyst 4 so that the exhaust gas is exhausted at an early stage.
- the oxygen concentration can be measured.
- the oxygen sensor 6 is provided on the downstream side of the electrically heated catalyst 4, but an air-fuel ratio sensor may be provided instead. That is, an air-fuel ratio sensor that outputs a signal corresponding to the air-fuel ratio may be provided, and failure detection may be performed based on the time from when the internal combustion engine 1 is started until the rich air-fuel ratio is detected by the air-fuel ratio sensor.
- This embodiment is different from the first embodiment in the processing performed in step S105. Since other devices are the same as those in the first embodiment, the description thereof is omitted.
- failure detection of the electrically heated catalyst 4 is performed using the output values of the air-fuel ratio sensor 5 and the oxygen sensor 6.
- FIG. 5 is a flowchart showing a flow of a failure determination process using the air-fuel ratio sensor 5 and the oxygen sensor 6 according to the second embodiment.
- This routine is executed in step S105.
- symbol is attached
- step S301 transitions of output values of the air-fuel ratio sensor 5 and the oxygen sensor 6 are read. That is, the output values of the air-fuel ratio sensor 5 and the oxygen sensor 6 are stored in the ECU 10, and the transition of the output values is obtained.
- step S302 it is calculated whether or not the catalyst is activated.
- this step it is calculated whether or not the catalyst is activated based on the transition of the output values of the air-fuel ratio sensor 5 and the oxygen sensor 6.
- the output value of the air-fuel ratio sensor 5 is not affected by the electrically heated catalyst 4.
- the air-fuel ratio detected by the air-fuel ratio sensor 5 is the air-fuel ratio of the exhaust before flowing into the electrically heated catalyst 4. Accordingly, the output value of the air-fuel ratio sensor 5 shows a rich air-fuel ratio immediately after the internal combustion engine 1 is started, and thereafter continues to change at the rich air-fuel ratio.
- the output value of the oxygen sensor 6 is affected by the electrically heated catalyst 4 as described in the first embodiment. For this reason, the transition of the output value of the oxygen sensor 6 differs depending on whether or not the catalyst is activated. If the catalyst is activated when the internal combustion engine 1 is started, the time from when the internal combustion engine 1 is started until the rich air-fuel ratio is detected by the air-fuel ratio sensor 5 and the oxygen sensor 6 becomes longer. Therefore, for example, when this time is longer than a predetermined time, it is determined that the catalyst is activated.
- the predetermined time here is the upper limit of the time from when the internal combustion engine 1 is started when the electrically heated catalyst 4 is out of order until the output values of the air-fuel ratio sensor 5 and the oxygen sensor 6 indicate a rich air-fuel ratio. Value.
- step S303 it is determined whether or not it has been calculated in step S302 that the catalyst is activated. If an affirmative determination is made in step S303, the process proceeds to step S205, where it is determined that the electrically heated catalyst 4 is normal, assuming that the catalyst is activated. On the other hand, if a negative determination is made, the process proceeds to step S206, and it is determined that the electrically heated catalyst 4 has failed because the catalyst is not activated.
- failure detection is performed using the temperature of the electrically heated catalyst 4 estimated based on the electrical resistance of the electrically heated catalyst 4 together. That is, failure detection is performed based on the time until the output value of the oxygen sensor 6 changes to a value indicating a rich air-fuel ratio and the temperature estimated based on the electrical resistance.
- the accuracy of failure detection can be improved.
- the internal combustion engine 1 is started to detect a failure of the electric heating catalyst 4.
- the accuracy of failure detection can be improved by positively starting the internal combustion engine 1 when the electrically heated catalyst 4 is stable at a high temperature.
- the electric motor 2 rotates the crankshaft of the internal combustion engine 1 while energizing the electrically heated catalyst 4.
- air is discharged from the internal combustion engine 1 and air is fed into the electrically heated catalyst 4.
- sufficient oxygen can be stored in the catalyst in advance, so that the accuracy of failure detection can be improved.
- the time required for failure detection can be shortened.
- the suppression of the electrically heated catalyst 4 being cooled by the exhaust, the suppression of the discharge of unburned fuel, and the completion of the failure detection in a short time are performed.
- the internal combustion engine 1 is controlled so as to be realized.
- the exhaust gas having a low temperature flows into the electrically heated catalyst 4. If it is suppressed that the electrically heated catalyst 4 is cooled by this exhaust gas, the exhaust gas purification rate can be kept high.
- emission of unburned fuel is suppressed, it can suppress that unburned fuel is discharge
- failure detection can be completed in a short time, it can be made less susceptible to the influence of the operating state of the internal combustion engine 1, so that the accuracy of failure detection can be increased.
- the internal combustion engine 1 is controlled so that the ignition timing is on the advance side with respect to the top dead center and the air-fuel ratio is on the rich side with respect to the stoichiometric air-fuel ratio.
- the combustion state can be stabilized and the combustion gas temperature can be raised, so that the electrically heated catalyst 4 is suppressed from being cooled by exhaust gas, the discharge of unburned fuel is suppressed, and the failure in a short time
- the completion of detection can be realized.
- FIG. 6 is a flowchart showing a temporary failure determination flow of the electrically heated catalyst 4 according to the present embodiment.
- symbol is attached
- step S401 it is determined whether the electric heating catalyst 4 is energized. That is, it is determined whether or not the temperature of the electrically heated catalyst 4 is being raised. If an affirmative determination is made in step S401, the process proceeds to step S402, and if a negative determination is made, the process proceeds to step S103.
- step S402 it is determined whether or not the catalyst leaning process is not performed.
- the catalyst leaning process is a process of sending air to the electrically heated catalyst 4 before supplying fuel to the internal combustion engine 1 and starting it.
- fuel is not supplied to the internal combustion engine 1, and the crankshaft of the internal combustion engine 1 is rotated by the electric motor 2. That is, air is discharged from the internal combustion engine 1.
- the electrically heated catalyst 4 is energized.
- oxygen is stored in the electrically heated catalyst 4 as the temperature of the electrically heated catalyst 4 increases. That is, oxygen can be stored in the catalyst before the internal combustion engine 1 is started.
- step S402 If a positive determination is made in step S402, the process proceeds to step S403. If a negative determination is made, the process proceeds to step S404.
- step S403 a catalyst leaning process is performed.
- the catalyst leaning process is performed until the temperature of the electrically heated catalyst 4 becomes higher than the predetermined value.
- a temporary failure determination process is performed.
- the temporary failure determination process is a process for determining whether or not the electric heating catalyst 4 is normal from the estimated value of the temperature of the electric heating catalyst 4.
- the temperature of the electrically heated catalyst 4 is estimated based on the electrical resistance of the electrically heated catalyst 4 when the electrically heated catalyst 4 is energized. Details will be described later.
- step S401 when a negative determination is made in step S401, the process proceeds to step S103, and it is determined whether or not energization to the electrically heated catalyst 4 is completed. If an affirmative determination is made in step S103, the process proceeds to step S405.
- step S405 the internal combustion engine 1 is started. At this time, fuel is supplied to the internal combustion engine 1. In this step, the internal combustion engine 1 is started to perform failure detection.
- step S406 the failure determination process is performed. This failure determination process will be described later.
- step S407 the internal combustion engine 1 is stopped. That is, the internal combustion engine 1 is operated only while the failure determination process is being performed.
- FIG. 7 is a flowchart showing the flow of the temporary failure determination process.
- step S501 the temperature of the electrically heated catalyst 4 is estimated from the electrical resistance of the electrically heated catalyst 4. This estimation is obtained from the relationship shown in FIG.
- the ECU 10 that detects the electric resistance of the electrically heated catalyst 4 corresponds to the resistance detecting device in the present invention.
- the ECU 10 that estimates the temperature of the electrically heated catalyst 4 in step S501 corresponds to the estimation device in the present invention.
- step S502 it is determined whether or not the temperature estimated in step S501 is higher than a predetermined value.
- the predetermined value here is an upper limit value of the temperature at which the electrically heated catalyst 4 is considered to be in failure, and is set in advance.
- step S502 If an affirmative determination is made in step S502, the process proceeds to step S503, and it is determined that the electrically heated catalyst 4 is normal in the provisional determination. In addition, if a negative determination is made in step S502, the process proceeds to step S504, and it is determined that the electrically heated catalyst 4 has failed in the temporary determination.
- step S503 since the accuracy is low even if the temperature is estimated based on the electric resistance of the electrically heated catalyst 4, the accuracy of the provisional determination is low. For this reason, failure detection of the electrically heated catalyst 4 based only on the estimated temperature value is not performed, but failure detection is performed using an output value of an oxygen sensor 6 described later.
- FIG. 8 is a flowchart showing the flow of this failure determination process.
- symbol is attached
- step S601 it is determined whether or not the elapsed time from the start of the internal combustion engine 1 measured in step S203 is longer than a predetermined time and is normal in the provisional determination.
- This predetermined time is the same as the predetermined time described in step S204.
- the elapsed time from the start of the internal combustion engine 1 measured in step S203 being longer than the predetermined time means that the oxygen storage amount of the catalyst was sufficiently large, and the electrically heated catalyst 4 Is likely to be normal.
- the provisional determination is normal, there is a high possibility that the electrically heated catalyst 4 is normal. Therefore, in this embodiment, when the elapsed time measured in step S203 is longer than the predetermined time and is normal in the provisional determination, it is determined that the electrically heated catalyst 4 is normal.
- step S601 If an affirmative determination is made in step S601, the process proceeds to step S205, where it is determined that the electrically heated catalyst 4 is normal. On the other hand, if a negative determination is made in step S601, the process proceeds to step S602.
- step S602 it is determined whether the elapsed time from the start of the internal combustion engine 1 measured in step S203 is shorter than a predetermined time and whether or not a failure has occurred in the provisional determination.
- the fact that the elapsed time measured in step S203 is shorter than the predetermined time means that the amount of oxygen stored in the catalyst is not sufficient, and there is a high possibility that the electrically heated catalyst 4 has failed.
- the elapsed time measured in step S203 is shorter than the predetermined time and the failure is determined as a result of the tentative determination, it is determined that the electrically heated catalyst 4 has failed.
- step S602 determines whether the electrically heated catalyst 4 has failed. If a negative determination is made in step S602, the process proceeds to step S603.
- step S603 the determination as to whether or not the electrically heated catalyst 4 is normal is suspended. That is, since the elapsed time measured after the start of the internal combustion engine 1 measured in step S203 is inconsistent with the provisional determination result, the final determination (main determination) is suspended. For example, when the operating state of the internal combustion engine 1 deteriorates, the output value of the oxygen sensor 6 is not stable, and thus the elapsed time may be measured incorrectly. In such a case, accuracy can be improved by performing failure detection again. In step S603, it may be determined that the electrically heated catalyst 4 has failed.
- FIG. 9 is another flowchart showing the flow of the failure determination process.
- symbol is attached
- step S701 it is determined whether the catalyst is activated in step S302 and is normal in the provisional determination.
- the calculation that the catalyst is activated in step S302 means that the oxygen storage amount of the catalyst is sufficiently large, and there is a high possibility that the electrically heated catalyst 4 is normal. In addition, even when the provisional determination is normal, there is a high possibility that the electrically heated catalyst 4 is normal. Therefore, in this embodiment, it is calculated that the catalyst is activated in step S302, and it is determined that the electrically heated catalyst 4 is normal when the provisional determination indicates normal.
- step S701 when an affirmative determination is made in step S701, the process proceeds to step S205, where it is determined that the electrically heated catalyst 4 is normal. On the other hand, if a negative determination is made in step S701, the process proceeds to step S702.
- step S702 it is determined whether or not the catalyst has not been activated in step S302, and whether or not a failure has occurred in the provisional determination.
- the fact that the catalyst is not activated in step S302 means that the amount of oxygen stored in the catalyst is not sufficient, and there is a high possibility that the electrically heated catalyst 4 has failed.
- step S702 when an affirmative determination is made in step S702, the process proceeds to step S206, where it is determined that the electrically heated catalyst 4 has failed. On the other hand, if a negative determination is made in step S702, the process proceeds to step S603 and the determination is suspended.
- the failure detection based on the oxygen sensor 6 and the failure determination based on the electrical resistance are used in combination, thereby further improving the accuracy of failure detection of the electrically heated catalyst 4. be able to.
Abstract
Description
内燃機関の排気通路に設けられ通電により発熱して触媒を加熱する電気加熱式触媒の故障検出装置において、
前記内燃機関の始動時に前記電気加熱式触媒に流入する排気の空燃比をリッチ空燃比とする空燃比制御装置と、
前記電気加熱式触媒よりも下流側に設けられ排気中の酸素濃度を検知する下流側検知装置と、
前記内燃機関の始動後であって前記空燃比制御装置により排気の空燃比がリッチ空燃比とされているときに前記下流側検知装置により検知される酸素濃度がリッチ空燃比を示す値に変化する時期に基づいて前記電気加熱式触媒へ通電されているか否か判定する判定装置と、
を備える。
所定時間よりも長い場合に前記電気加熱式触媒への通電が正常に行われていると判定し、
所定時間以下の場合に前記電気加熱式触媒への通電が正常に行われていないと判定することができる。
前記判定装置は、前記内燃機関が始動されてから、前記上流側検知装置及び下流側検知装置により検知される酸素濃度が共にリッチ空燃比を示す値となるまでの時間が、
所定時間よりも長い場合に前記電気加熱式触媒への通電が正常に行われていると判定し、
所定時間以下の場合に前記電気加熱式触媒への通電が正常に行われていないと判定することができる。
前記抵抗検知装置により検知される電気抵抗に基づいて前記電気加熱式触媒の温度を推定する推定装置と、
を備え、
前記判定装置は、前記推定装置により推定される前記電気加熱式触媒の温度が所定値よりも高いときに、前記電気加熱式触媒へ通電されているか否か判定することができる。
前記抵抗検知装置により検知される電気抵抗に基づいて前記電気加熱式触媒の温度を推定する推定装置と、
を備え、
前記判定装置が、前記電気加熱式触媒へ通電されていると判定するのは、前記推定装置により推定される前記電気加熱式触媒の温度が所定値よりも高い場合に限ることができる。
2 電動モータ
3 排気通路
4 電気加熱式触媒
5 空燃比センサ
6 酸素センサ
10 ECU
Claims (6)
- 内燃機関の排気通路に設けられ通電により発熱して触媒を加熱する電気加熱式触媒の故障検出装置において、
前記内燃機関の始動時に前記電気加熱式触媒に流入する排気の空燃比をリッチ空燃比とする空燃比制御装置と、
前記電気加熱式触媒よりも下流側に設けられ排気中の酸素濃度を検知する下流側検知装置と、
前記内燃機関の始動後であって前記空燃比制御装置により排気の空燃比がリッチ空燃比とされているときに前記下流側検知装置により検知される酸素濃度がリッチ空燃比を示す値に変化する時期に基づいて前記電気加熱式触媒へ通電されているか否か判定する判定装置と、
を備える電気加熱式触媒の故障検出装置。 - 前記判定装置は、前記内燃機関が始動されてから、前記下流側検知装置により検知される酸素濃度がリッチ空燃比を示す値に変化するまでの時間が、
所定時間よりも長い場合に前記電気加熱式触媒への通電が正常に行われていると判定し、
所定時間以下の場合に前記電気加熱式触媒への通電が正常に行われていないと判定する請求項1に記載の電気加熱式触媒の故障検出装置。 - 前記電気加熱式触媒よりも上流側に設けられ排気中の酸素濃度を検知する上流側検知装置を備え、
前記判定装置は、前記内燃機関が始動されてから、前記上流側検知装置及び下流側検知装置により検知される酸素濃度が共にリッチ空燃比を示す値となるまでの時間が、
所定時間よりも長い場合に前記電気加熱式触媒への通電が正常に行われていると判定し、
所定時間以下の場合に前記電気加熱式触媒への通電が正常に行われていないと判定する請求項1に記載の電気加熱式触媒の故障検出装置。 - 前記電気加熱式触媒へ前記内燃機関の始動前から通電する請求項1から3の何れか1項に記載の電気加熱式触媒の故障検出装置。
- 前記電気加熱式触媒へ通電したときの該電気加熱式触媒の電気抵抗を検知する抵抗検知装置と、
前記抵抗検知装置により検知される電気抵抗に基づいて前記電気加熱式触媒の温度を推定する推定装置と、
を備え、
前記判定装置は、前記推定装置により推定される前記電気加熱式触媒の温度が所定値よりも高いときに、前記電気加熱式触媒へ通電されているか否か判定する請求項1から4の何れか1項に記載の電気加熱式触媒の故障検出装置。 - 前記電気加熱式触媒へ通電したときの該電気加熱式触媒の電気抵抗を検知する抵抗検知装置と、
前記抵抗検知装置により検知される電気抵抗に基づいて前記電気加熱式触媒の温度を推定する推定装置と、
を備え、
前記判定装置が、前記電気加熱式触媒へ通電されていると判定するのは、前記推定装置により推定される前記電気加熱式触媒の温度が所定値よりも高い場合に限る請求項1から4の何れか1項に記載の電気加熱式触媒の故障検出装置。
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EP10860784.7A EP2653683B1 (en) | 2010-12-15 | 2010-12-15 | Failure detection apparatus for an electrically heated catalyst |
PCT/JP2010/072560 WO2012081094A1 (ja) | 2010-12-15 | 2010-12-15 | 電気加熱式触媒の故障検出装置 |
US13/994,570 US8776586B2 (en) | 2010-12-15 | 2010-12-15 | Failure detection apparatus for an electrically heated catalyst |
JP2012548573A JP5348336B2 (ja) | 2010-12-15 | 2010-12-15 | 電気加熱式触媒の故障検出装置 |
CN201080070658.XA CN103261604B (zh) | 2010-12-15 | 2010-12-15 | 电加热式催化剂的故障检测装置 |
KR1020137017449A KR101331370B1 (ko) | 2010-12-15 | 2010-12-15 | 전기 가열식 촉매의 고장 검출 장치 |
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KR (1) | KR101331370B1 (ja) |
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WO (1) | WO2012081094A1 (ja) |
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US9297843B2 (en) * | 2013-03-15 | 2016-03-29 | GM Global Technology Operations LLC | Fault diagnostic systems and methods using oxygen sensor impedance |
JP5783202B2 (ja) * | 2013-03-27 | 2015-09-24 | トヨタ自動車株式会社 | 内燃機関の異常検出装置 |
US10221792B2 (en) * | 2013-08-15 | 2019-03-05 | Ford Global Technologies, Llc | Two-stage catalyst regeneration |
JP6376169B2 (ja) * | 2016-04-20 | 2018-08-22 | トヨタ自動車株式会社 | ハイブリッド車両 |
JP6424861B2 (ja) * | 2016-04-20 | 2018-11-21 | トヨタ自動車株式会社 | ハイブリッド車両 |
DE102016219387B4 (de) * | 2016-10-06 | 2019-01-24 | Audi Ag | Verfahren und Vorrichtung zur Kalibrierung eines Abgassensors |
DE102017107678A1 (de) * | 2017-04-10 | 2018-10-11 | Volkswagen Aktiengesellschaft | Verfahren zur Inbetriebnahme eines Verbrennungsmotors und Kraftfahrzeug mit einem Verbrennungsmotor |
JP2021110321A (ja) * | 2020-01-15 | 2021-08-02 | トヨタ自動車株式会社 | 内燃機関の触媒劣化判断装置 |
US11268416B2 (en) * | 2020-05-19 | 2022-03-08 | Denso International America, Inc. | Methods and systems for detecting an impedance of a catalytic converter |
IT202100017255A1 (it) * | 2021-06-30 | 2022-12-30 | Marelli Europe Spa | Metodo di controllo di un bruciatore per un sistema di scarico di un motore a combustione interna |
CN114033536B (zh) * | 2021-11-29 | 2022-09-13 | 东风汽车有限公司东风日产乘用车公司 | 三元催化器加热控制方法、装置、设备及存储介质 |
CN114542251B (zh) * | 2022-03-18 | 2023-01-20 | 潍柴动力股份有限公司 | 一种电加热催化剂载体电阻故障诊断方法及系统 |
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- 2010-12-15 CN CN201080070658.XA patent/CN103261604B/zh not_active Expired - Fee Related
- 2010-12-15 US US13/994,570 patent/US8776586B2/en not_active Expired - Fee Related
- 2010-12-15 JP JP2012548573A patent/JP5348336B2/ja not_active Expired - Fee Related
- 2010-12-15 KR KR1020137017449A patent/KR101331370B1/ko active IP Right Grant
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Also Published As
Publication number | Publication date |
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JPWO2012081094A1 (ja) | 2014-05-22 |
CN103261604B (zh) | 2014-11-12 |
KR101331370B1 (ko) | 2013-11-20 |
JP5348336B2 (ja) | 2013-11-20 |
US20130291630A1 (en) | 2013-11-07 |
EP2653683A1 (en) | 2013-10-23 |
US8776586B2 (en) | 2014-07-15 |
EP2653683B1 (en) | 2017-01-25 |
EP2653683A4 (en) | 2014-06-11 |
KR20130087608A (ko) | 2013-08-06 |
CN103261604A (zh) | 2013-08-21 |
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