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WO2010013123A1 - Internal combustion engine control apparatus for egr passage diagnosis - Google Patents

Internal combustion engine control apparatus for egr passage diagnosis Download PDF

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Publication number
WO2010013123A1
WO2010013123A1 PCT/IB2009/006393 IB2009006393W WO2010013123A1 WO 2010013123 A1 WO2010013123 A1 WO 2010013123A1 IB 2009006393 W IB2009006393 W IB 2009006393W WO 2010013123 A1 WO2010013123 A1 WO 2010013123A1
Authority
WO
WIPO (PCT)
Prior art keywords
egr
passage
internal combustion
combustion engine
egr passage
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/IB2009/006393
Other languages
French (fr)
Inventor
Toyokazu Nakashima
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.)
Toyota Motor Corp
Original Assignee
Toyota Motor 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 Toyota Motor Corp filed Critical Toyota Motor Corp
Publication of WO2010013123A1 publication Critical patent/WO2010013123A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/22—Safety or indicating devices for abnormal conditions
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • 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
    • F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D41/0047—Controlling exhaust gas recirculation [EGR]
    • F02D41/005—Controlling exhaust gas recirculation [EGR] according to engine operating conditions
    • F02D41/0055—Special engine operating conditions, e.g. for regeneration of exhaust gas treatment apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
    • F02M26/22—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories with coolers in the recirculation passage
    • F02M26/23—Layout, e.g. schematics
    • F02M26/25—Layout, e.g. schematics with coolers having bypasses
    • F02M26/26—Layout, e.g. schematics with coolers having bypasses characterised by details of the bypass valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/49—Detecting, diagnosing or indicating an abnormal function of the EGR system
    • 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
    • F02D2200/04—Engine intake system parameters
    • F02D2200/0406—Intake manifold pressure
    • 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
    • F02D41/18—Circuit arrangements for generating control signals by measuring intake air flow
    • 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 invention relates to a control apparatus for an internal combustion engine provided with an exhaust gas recirculation (EGR) device that recirculates to an intake passage a portion of exhaust gas discharged from a combustion chamber into an exhaust passage.
  • EGR exhaust gas recirculation
  • EGR devices are provided in internal combustion engines (to be referred to as engines) installed in automobiles and the like for the purpose of reducing nitrogen oxides (NOx) contained in exhaust gas discharged from the combustion chambers.
  • EGR devices recirculate a portion of the exhaust gas discharged into an exhaust passage to the intake passage through an EGR passage in the form of recirculated gas, and inhibits the formation of NOx by mixing with the air-fuel mixture to lower the combustion temperature.
  • EGR passage abnormality detection is carried out by, for example, opening the EGR passage on the side of the EGR cooler by controlling the switching control valve during vehicle deceleration, if the EGR passage is opened with EGR gas remaining in the passage immediately after deceleration, unburaed fuel components contained in the EGR gas are taken into the EGR cooler resulting in the possibility of promoting clogging of the EGR cooler.
  • a fuel addition valve for adding fuel to the exhaust manifold if the EGR passage is opened to detect clogging thereof when added fuel is present in the exhaust manifold, this can similarly result in the possibility of promoting clogging of the EGR cooler.
  • the invention provides a control apparatus for an internal combustion engine provided with an EGR device that recirculates a portion of exhaust gas discharged from combustion chambers into an exhaust passage into an intake passage, and which realizes control capable of inhibiting promotion of clogging of an EGR cooler when detecting abnormalities in an EGR passage.
  • the invention provides a control apparatus for an internal combustion engine provided with an EGR device having an EGR passage that recirculates to an intake passage a portion of exhaust gas discharged into an exhaust passage of an internal combustion engine, an EGR valve which is provided in the EGR passage and which adjusts an amount of exhaust gas recirculated from the exhaust passage to the intake passage, and an EGR cooler provided in the EGR passage, wherein the control apparatus is further provided with a switching device that controls opening and closing of the EGR passage and an abnormality detection device that detects abnormalities in the EGR device, and the abnormality detection device detects abnormalities in the EGR passage by opening the EGR passage by the control of the switching device when the inside of the exhaust passage upstream of the EGR cooler
  • the invention provides a control apparatus for an internal combustion engine provided with an EGR device provided with an EGR passage that recirculates to an intake passage a portion of exhaust gas discharged into an exhaust passage of an internal combustion engine, an EGR valve which is provided in the EGR passage and which adjusts an amount of exhaust gas recirculated from the exhaust passage to the intake passage, an EGR cooler provided in the EGR passage, a bypass passage that bypasses the EGR cooler, and a control valve that adjusts the opening of the EGR passage and the opening of the bypass passage; wherein the control apparatus is further provided with an abnormality detection device for detecting abnormalities in the EGR device, and the abnormality detection device detects abnormalities in the EGR passage by opening the EGR passage on the side of the EGR cooler by the control of the control valve when the inside of the exhaust passage upstream of the EGR cooler (upstream side of EGR gas flow) has been scavenged after the criterion for detecting abnormalities in the EGR passage
  • EGR gas containing unburned fuel components and added fuel into the EGR cooler can be prevented during EGR passage abnormality detection. As a result, promotion of clogging of the EGR cooler can be inhibited.
  • EGR passage abnormality detection is preferably carried out when an amount of time equivalent to the amount of time required for that scavenging (delay time) has elapsed.
  • the delay time from the time abnormality detection criterion has been satisfied is acquired by, for example, determining by experimentation and calculation the amount of time for the concentration of fuel components in the exhaust passage upstream of the ECR cooler to decrease to a concentration that does not promote clogging of the EGR cooler, and the value (delay time) empirically determined on the basis of that result is set for the delay time.
  • EGR passage abnormality detection is also preferably carried out when the inside of the exhaust passage upstream of the EGR cooler has been scavenged with fresh air after the criterion for detecting abnormalities in the EGR passage has been satisfied, and die concentration of fuel components in the exhaust passage upstream of the EGR cooler (and more specifically, the exhaust manifold, for example) has decreased to equal to or less than a judgment threshold value.
  • the judgment threshold value for fuel component concentration is acquired, for example, by determining by experimentation and calculation the relationship between the concentration of fuel components in gas passing through the EGR passage and the amount of fuel components adhered inside the EGR cooler, and the concentration (allowable value) of fuel components that does not promote clogging of the EQR cooler empirically determined on the basis of that relationship is set for the judgment threshold value.
  • a preferable specific configuration of a method for detecting abnormalities in an EGR passage consists of detecting the amount of clogging of the EGR passage based on the amount of change in the amount of intake air when the EGR valve is opened and when the EGR valve is closed while the EGR passage is opened, and then determining the presence of an abnormality in the EGR passage based on the results of detection.
  • another preferable specific configuration of a method for detecting abnormalities in an EGR passage consists of detecting the amount of clogging of the EGR passage based on the amount of change in pressure within the intake manifold when the EGR valve is opened and when the EGR valve is closed while the EGR passage is opened, and then determining the presence of an abnormality in the EGR passage based on the results of detection.
  • the criterion for detecting abnormalities in the EGR passage as the criterion for detecting abnormalities in the EGR system preferably consist of, for example, when the vehicle is decelerating or when operating in an operating range of the internal combustion engine suitable for detection of abnormalities in the EGR passage, such as an operating state during which combustion status is favorable as is such after the internal combustion engine has warmed up.
  • EGR passage abnormality detection or bypass passage abnormality detection may be allowed to be carried out selectively in the invention corresponding to the operating range of the internal combustion engine.
  • EGR passage abnormality detection may be made to not be carried out while bypass passage abnormality detection may be allowed to be carried out in operating ranges in which combustion status of the internal combustion engine is poor in consideration of these factors.
  • EGR passage abnormality detection is carried out after a criterion for detecting abnormalities in the EGR passage has been satisfied when the inside of the exhaust passage upstream of the EGR cooler has been scavenged, entrance of EGR gas and added fuel into the EGR cooler during detection of abnormalities can be prevented. As a result, promotion of clogging of the EGR cooler can be inhibited.
  • FIQ 1 is a schematic block diagram showing an example of a diesel engine to which an embodiment of the invention is applied;
  • FIG 2 is a block diagram showing the configuration of the control system such as an electronic control unit (ECU) shown in FIQ 1;
  • ECU electronice control unit
  • FIGS. 3A and 3B are schematic drawings for explaining a method for detecting the amount of clogging of an EGR passage in the embodiment
  • FIG 4 is a drawing showing the flow of intake air when clogging has occurred in an EGR cooler in the method for detecting the amount of clogging of FIGS. 3A and 3B;
  • FIG. S is a flow chart showing a control routine for abnormality detection processing of the embodiment carried out in an ECU.
  • FIG 6 is a timing chart for abnormality detection processing of the embodiment carried out in an ECU.
  • a diesel engine 1 of this example (to be referred to as "engine 1") is, for example, a common rail, fuel-injected 4-cylinder engine, and is composed by having for main components thereof a fuel supply system 2, combustion chambers 3, an intake system 6 and an exhaust system 7.
  • the fuel supply system 2 is provided with a supply pump 21, a common rail 22, injectors (fuel injection valves) 23, a shutoff valve 24, a fuel addition valve 25, a fuel pressure control valve 26, a fuel control valve 27, an engine fuel passage 28 and an added fuel passage 29.
  • the supply pump 21 pumps fuel from a fuel tank and after pressurizing the pumped fuel, supplies the pressurized fuel to the common rail 22 through the engine fuel passage 28.
  • the common rail 22 has the function of a pressure accumulation chamber that maintains pressurized fuel supplied from the supply pump 21 at a prescribed pressure (pressure accumulation), and this fuel for which pressure has been maintained is distributed to each injector 23.
  • the injectors 23 are electromagne ⁇ ' cally driven on-off valves that open when a prescribed voltage has been applied and inject fuel into the combustion chambers 3.
  • the supply pump 21 supplies a portion of the fuel pumped from the fuel tank to the fuel addition valve 25 through the added fuel passage 29.
  • the fuel addition valve 25 is an electromagneticaUy driven on-off valve that opens when a prescribed voltage has been applied and adds fuel to an exhaust manifold 72 to be described later from exhaust ports 71 of the exhaust system 7. During an emergency, the shutoff valve 24 stops the supply of fuel by blocking the added fuel passage 29.
  • the intake system 6 is provided with an intake manifold 62 connected to intake ports formed in cylinder heads, and an intake pipe 64 composing an intake passage is connected to this intake manifold 62.
  • an air cleaner 65, an air flow meter ' 32, an intercooler 61 to be described later, a throttle valve 63, an intake temperature sensor 33 and an intake pressure sensor 34 are arranged in order starting from the upstream side in the intake system 6.
  • the intake manifold 62 composes a portion of the intake passage.
  • the exhaust system 7 is provided with an exhaust manifold 72 connected to the exhaust ports 71 formed in cylinder heads, and exhaust pipes 73 and 74 composing the exhaust passage are connected to this exhaust manifold 72.
  • a catalyst device 4 is arranged in mis exhaust passage.
  • the exhaust manifold 72 composes a portion of the exhaust passage.
  • the catalyst device 4 is provided with an NOx storage reduction (NSR) catalyst 41 and a diesel particulate-NOx reduction system (DPNR) catalyst 42.
  • NSR NOx storage reduction
  • DPNR diesel particulate-NOx reduction system
  • the NSR catalyst 41 is an NOx occlusion-reduction catalyst having a composition consisting of, for example, an alumina (Al 2 Ch) support and an alkaline metal such as potassium (K), sodium (Na), lithium (Ii) or cesium (Cs) 1 alkaline earth such as barium (Ba) or calcium (Ca), rare earth such as lanthanum (La) or yttrium (Y), or a precious metal such as platinum (Pt), loaded on the support
  • an alkaline metal such as potassium (K), sodium (Na), lithium (Ii) or cesium (Cs) 1 alkaline earth such as barium (Ba) or calcium (Ca), rare earth such as lanthanum (La) or yttrium (Y), or a precious metal such as platinum (Pt), loaded on the support
  • the NSR catalyst 41 occludes NOx when a large amount of oxygen is present in the exhaust gas, and reduces NOx to NO2 or NO followed by the release thereof when the oxygen concentration of the exhaust gas is low and there are large amounts of reducing components (such as unbumed fuel components (HC)) present in the exhaust gas.
  • reducing components such as unbumed fuel components (HC)
  • the NOx that have been released in the form OfNO 2 or NO in this manner are further reduced to N 2 by rapidly reacting with HC and CO present in the exhaust gas.
  • the HC and CO are oxidized to H 2 O and CO 2 as a result of reducing NO 2 and NO.
  • the DPNR catalyst 42 consists of, for example, loading an NOx occlusion-reduction catalyst onto a porous ceramic structure, and particulate matter (PM) present in exhaust gas is captured when the exhaust gas passes through the porous walls thereof.
  • PM particulate matter
  • NOx in the exhaust gas are occluded by the NOx occlusion-reduction catalyst, while in the case of a rich air-fuel ratio, occluded NOx are reduced and released.
  • a catalyst causing oxidation and combustion of captured PM (such as an oxidation catalyst having as a main component thereof a precious metal such as platinum) is loaded on the DPNR catalyst 42.
  • a turbocharger (supercharger) 5 is provided in the engine 1.
  • This turbocharger S is provided with a turbine wheel 52 and a compressor impeller 53 linked through a turbine. shaft 51.
  • the compressor impeller 53 is arranged facing towards the inside of the intake pipe 64, and the turbine wheel 52 is arranged facing towards the inside of the exhaust pipe 73.
  • This type of turbocharger 5 supercharges intake air by causing the compressor impeller 53 to rotate by utilizing exhaust flow (exhaust pressure) received by the turbine wheel 52.
  • the turbocharger 5 of this example is a variable nozzle type of turbocharger, has a variable nozzle vane mechanism 54 provided on the side of the turbine wheel 52, and is able to adjust the boost pressure of the engine 1 by adjusting the opening of this variable nozzle vane mechanism 54.
  • the intercooler 61 is provided in the intake pipe 64 of the intake system 6 for forcibly cooling intake air heated by supercharging in the turbocharger S.
  • the throttle valve 63 is provided downstream from this intercooler 61.
  • the throttle valve 63 is an electronically controlled on-off valve capable of continuously adjusting the opening thereof, reduces the flow path area of intake air under prescribed conditions, and has the function of adjusting (reducing) the amount of intake air supplied.
  • an EOR device 8 is provided in this engine 1.
  • the EGR device 8 lowers combustion temperature by resupplies a portion of the exhaust to the combustion chambers 3 by suitably recirculating to the intake system (intake passage) 6, thereby reducing the level of NOx emissions.
  • the EGR device 8 is provided with an EGR passage 81 that connects the intake manifold 62 of the intake system 6 and the exhaust manifold 72 of the exhaust system 7.
  • An EGR valve 82 and an EGR cooler 83 for cooling EGR gas passing (recirculating) through the EGR passage 81 are provided in the EGR passage 81, and the amount of EGR gas introduced from the exhaust system 7 to the intake system 6 (exhaust recirculation volume) can be adjusted by adjusting the opening of the EGR valve 82.
  • a bypass passage 84 that bypasses the EGR cooler 83 is provided in the EGR device 8.
  • a switching control valve 85 for adjusting the opening of the EGR passage 81 and the opening of the bypass passage 84 is provided in the connection between the bypass passage 84 and the EGR passage 81 (connection on the downstream side of EGR gas flow).
  • the ratio of the flow rates between the amount of EGR gas entering the EGR cooler 83 and the amount of EGR gas entering the bypass passage 84 can be arbitrarily adjusted by controlling this switching control valve 85.
  • the status of the flow of EGR gas can be set to a state in which EGR gas flows only to the EGR passage 81 while blocking the bypass passage 84 by fully opening the EGR passage 81 and fully closing the bypass passage 84, or to a state in which EGR gas flows only to the bypass passage 84 while blocking the EGR passage 81 by fully opening the bypass passage 84 and fully closing the EGR passage 81.
  • This type of switching control valve 85 is controlled with an ECU
  • the air flow meter 32 is arranged upstream of the throttle valve 63 of the intake system 6, and outputs a detection signal corresponding to the amount of intake air.
  • the intake temperature sensor 33 is arranged in the intake manifold 62, and outputs a detection signal corresponding to the temperature of intake air.
  • the intake pressure sensor 34 is arranged in the intake manifold 62, and outputs a detection signal corresponding to intake air pressure.
  • An A/F sensor 35 is arranged in the exhaust pipe 74 downstream from the catalyst device 4 of the exhaust system 7, and outputs a detection signal corresponding to the oxygen concentration in the exhaust gas (exhaust A/F).
  • An exhaust temperature sensor 36 is arranged in the exhaust pipe 74 downstream from the catalyst device 4 of me exhaust system 7, and outputs a detection signal corresponding to the temperature of exhaust gas (exhaust temperature).
  • a rail pressure sensor 37 outputs a detection signal corresponding to the pressure of fuel accumulating in the common rail
  • the ECU 100 is provided with a central processing unit (CPU) 101, a read-only memory (ROM) 102, a random access memory (RAM) 103, a backup RAM 104 and the like.
  • the ROM 102 stores various control programs and maps and the like referred to when executing the various control programs.
  • the CPU 101 executes various types of arithmetic processing based on various control programs and maps stored in the ROM 102.
  • the RAM 103 is a memory device for temporarily storing arithmetic processing results of the CPU 101 and data and the like input from various sensors
  • the backup RAM 104 is a non- volatile memory device for storing data and the like to be saved when the engine 1 is stopped.
  • ROM 102, CPU 101, RAM 103 and backup RAM 104 are mutually connected via a bus 107, and are connected to an input interface 105 and an output interface 106.
  • a coolant temperature sensor 31 which outputs a detection signal corresponding to coolant temperature of the engine 1, the air flow meter 32, the intake temperature sensor 33, the intake pressure sensor 34, and A/F sensor 35, the exhaust temperature sensor 36, the rail pressure sensor 37, an accelerator depression amount sensor 38, which outputs a detection signal corresponding to the amount of depression of the accelerator pedal, and a crankshaft position sensor 39, which detects the rotating speed of the output shaft of the engine 1 in the form of the crankshaft (engine rotating speed), are connected to the input interlace 1 OS.
  • the injectors 23, the shutoff valve 24, the fuel addition valve 25, the variable nozzle vane mechanism 54, the throttle valve 63, the EGR valve 82 and the switching control valve 85 are connected to the output interface 106.
  • the ECU 100 then executes various controls of the engine 1, including control of the amount of fuel injection, based on the outputs of each of the sensors described above. Moreover, the ECU 100 executes abnormality detection processing of the EOR device 8 described below.
  • control apparatus for an internal combustion engine of the invention is realized by a program executed by the ECU 100.
  • abnormality detection processing of the EGR device abnormality detection of die EGR passage 81 and abnormality detection of the bypass passage 84 can be carried out selectively corresponding to the operating range of the engine 1.
  • EGR passage abnormality detection is carried out while the engine 1 is in operation by opening and closing the EGR valve 82 in the state in which the switching control valve 85 is switched to the EGR cooler 83 side (EGR passage 81 "open" position). More specifically, as shown hi FIQ 3A, the amount of intake air (fresh air volume) GNl is first measured based on the output signal of the air flow meter 32 with the EGR valve 82 fully open. Next, as shown in FIG 3B, the amount of intake air (fresh air volume) GN2 is measured based on the output signal of the air flow meter 32 with the EGR valve 82 fully closed.
  • the amount of intake air GNl as determined by the measurement of FIG 3A decreases. Namely, in the measurement of FIG 3A, since EGR gas is recirculated to the intake manifold 62 through the EGR passage 81, the amount of intake air (fresh air volume) is smaller than the measurement of FIG 3B (GNl ⁇ GN2), and the difference in the amounts of intake air between the two ⁇ GNa ( ⁇ GNa -
  • the degree of clogging of the EGR passage 81 can be detected from the difference in the amounts of intake air ⁇ GNa between the case in which the EGR valve 82 is fully open and the case in which it is fully closed in the state in which the bypass passage 84 is blocked and the EGR passage 81 is ope ⁇
  • the EGR passage 81 can be determined to be normal in the case the difference in the amounts of intake air ⁇ GNa exceeds the judgment threshold value Tha, or the EGR passage 81 can be determined to be abnormal in the case the difference in the amounts of intake air ⁇ GNa is equal to or less than the judgment threshold value Tha.
  • the judgment threshold value Tha may be set in consideration of, for example, an on board diagnosis (OBD) defined value relating to exhaust emissions (PM NOx).
  • OBD on board diagnosis
  • detection of abnormalities in the bypass passage 84 can be similarly carried out by detecting the degree of clogging of the bypass passage 84 from the difference in the amounts of intake air ⁇ GNb ( ⁇ GNb -
  • the bypass passage 84 can be determined to be normal in the case the difference in the amounts of intake air ⁇ GNb exceeds the judgment threshold value Thb, or can be determined to be abnormal in the case the difference in the amounts of intake air ⁇ GNb is equal to or less than the judgment threshold value Thb.
  • judgment threshold value Thb used for bypass passage abnormality detection in this manner may be set in the same manner as in the case of EGR passage abnormality detection, or may be individually set to conforming values in consideration of OBD defined values relating to exhaust emissions (FMNOx).
  • the processing routine of FIG 5 is repeatedly executed at prescribed time intervals (such as every several msec to every several tens of msec) in the ECU 100.
  • Step STlOl a determination is made as to whether or not the abnormality detection criterion of the EGR device 8 (EGR system) has been satisfied. More specifically, when a determination is made as to whether or not a vehicle is decelerating and the vehicle is determined to be decelerating, the abnormality detection criterion is determined to be satisfied and processing proceeds to Step STl 02. Processing returns in the case the result of the determination of Step STlOl is determined to be negative.
  • the addition of fuel from the fuel addition valve 25 to the exhaust manifold 72 stops simultaneous to the start of vehicle deceleration as shown in FIG 6.
  • the EGR passage 81 is temporarily fully closed by controlling the switching control valve 85 when the abnormality detection criterion has been satisfied as a result of the start of vehicle deceleration.
  • Step STlOl an abnormality detection criterion
  • Step STl 02 a determination is made as to whether or not a prescribed delay time DT has elapsed from the time abnormality detection criterion have been satisfied, and processing proceeds to Step STl 03 when that delay time DT has elapsed (when the result of the determination of Step STl 02 has become positive).
  • the delay time DT used in the determination processing of this step STl 02 is set in consideration of the time required for EGR gas and added fuel remaining in the exhaust manifold 72 upstream of the EGR cooler 83 (and which may include a portion of the EGR passage 81) to be scavenged with fresh air at the time abnormality detection criterion has been satisfied. More specifically, the time for the concentration of fuel components in the exhaust manifold 72 to decrease to equal to or lower than an allowed value (concentration of fuel components able to inhibit promotion of clogging of the EGR cooler 83) as a result of scavenging with fresh air is extracted in advance by experimentation and calculation, and the value (time) that conforms to those results is set as the delay time DT.
  • Step ST103 a determination is made as to whether the detection range is the detection range of the EGR passage 81 (to be referred to as the EGR passage detection range), and in the case the result of that determination is positive, processing proceeds to Step ST104. In the case the result of the determination of Step S 103 is negative, processing proceeds to Step STl 06.
  • Step STl 03 the EGR passage 81 is opened (the bypass passage 84 is closed) under the control of the switching control valve 85, and the EGR passage 81 is connected between the exhaust manifold 72 and the intake manifold 62 (Step STl 04).
  • the difference in amounts of intake air ⁇ GNa calculated in this manner is then compared with the above-mentioned judgment threshold value Tha, and in the case the difference in amounts of intake air ⁇ GNa exceeds the judgment threshold value Tha, the EGR passage 81 is determined to be normal, while if the difference in amounts of intake air ⁇ GNa is equal to or less than the judgment threshold value Tha, the EGR passage 81 is determined to be abnormal (Step STl 05).
  • Step STl 03 In the case the result of the determination of Step STl 03 is negative (case of not being in the EGR passage detection range), abnormality detection is carried out on the bypass passage 84. More specifically, the bypass passage 84 is opened (the EGR passage 81 is closed) under the control of the switching control valve 85, and the bypass passage 84 is connected between the exhaust manifold 72 and the intake manifold 62 (Step STl 06).
  • the difference in amounts of intake air ⁇ GNb calculated in this manner is then compared with the above-mentioned judgment threshold value Thb, and in the case the difference in amounts of intake air ⁇ ONb exceeds the judgment threshold value Thb, the bypass passage 84 is determined to be normal, while if the difference in amounts of intake air ⁇ GNb is equal to or less than die judgment threshold value Thb, the bypass passage 84 is determined to be abnormal (Step STl 07).
  • abnormalities in the EGR device 8 may also be detected in the example described above by processing consisting of detecting the degree of clogging of the EGR passage 81 on the side of the EGR cooler 83 (abnormality detection) several times after the abnormality detection criterion of the EGR device 8 has been satisfied, and then switching the switching control valve 85 and detecting clogging of the bypass passage 84 (abnormality detection) several times.
  • clogging of the EGR passage 81 (or clogging of the bypass passage 84) is detected at the time an amount of time required for scavenging EGR gas and added value within the exhaust manifold 72 with fresh air (delay time DT) has elapsed after the abnormality detection criterion has been satisfied in the previously explained embodiment
  • the invention is not limited thereto, but rather as shown in FIG. 6, for example, after the abnormality detection criterion has been satisfied, clogging of the EGR passage 81 (or clogging of the bypass passage 84) may be detected at the time the concentration of fuel components in (he exhaust manifold 72 has decreasedto a prescribed judgment threshold value Nth or lower.
  • the judgment threshold value Nth for the concentration of fuel components in the exhaust manifold 72 can be acquired experimentally or by calculation from the relationship between the fuel component concentration of gas passing through the EGR passage 81 and the amount of fuel components adhered inside the EGR cooler 83, and then using the empirically determined value for the fuel component concentration that does not promote clogging of the EGR cooler 83 based on that relationship for the judgment threshold value Nth.
  • the fuel component concentration in the exhaust manifold 72 may be determined based on the oxygen concentration detected with the A/F sensor 35, or a sensor for detecting oxygen concentration in the exhaust manifold 72 may be provided, and fuel component concentration may be detected based on the output from that sensor.
  • the degree of clogging of the EGR passage 81 is detected in the above example by measuring the amount of change in the difference in quantities of intake air (intake air volume difference) between the amount of intake air when the EGR valve 82 is fully open and the amount of intake air when the EGR valve is fully closed when detecting abnormalities in the EGR device 8, the invention is not limited thereto, but rather the degree of clogging of the EGR passage 81 (or the bypass passage 84) may be detected based on the amount of change in the pressure within the intake manifold 62 (which may also be referred to as intake manifold pressure), an explanation of which is provided below.
  • the degree of clogging of the EGR passage 81 can be detected from the amount of change in intake manifold pressure ⁇ PIN between the case in which the EGR valve 82 is fully open and the case in which it is fully closed in the state in which the bypass passage 84 is blocked and the EGR passage 81 is open.
  • the EGR passage 81 can be determined to be normal in the case the amount of change in intake manifold pressure ⁇ PIN exceeds the judgment threshold value, while the EGR passage 81 can be determined to be abnormal in the case the amount of change in intake manifold pressure ⁇ PIN is equal to or less than the judgment threshold value.
  • intake manifold pressure can be measured based on an output signal from an intake pressure sensor 34 arranged in the intake manifold 62.
  • bypass passage 84 can be determined to be normal or abnormal based on the detection result
  • the invention is not limited thereto, but rather can also be applied to, for example, a fuel-injected 6-cylinder diesel engine or other diesel engine having an arbitrary number of cylinders.
  • the invention is not limited to a fiiel-injected diesel engine, but rather can also be applied to the control of other types of diesel engines as well.
  • the invention is not limited to diesel engines, but rather can be applied to the control of gasoline engines as well.

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Abstract

An abnormality in an EGR passage (81) is diagnosed by detecting a degree of clogging of the EGR passage (81) at the time when a prescribed delay time DT has elapsed, or in other words, at the time when EGR gas and added fuel remaining in an exhaust manifold (72) upstream of an EGR cooler (83) has been scavenged with fresh air, after a criterion for detecting an abnormality in the EGR passage (81) of an EGR device (8) has been satisfied. As a result of detecting an abnormality in the EGR passage (81) after the inside of the exhaust manifold (72) has been scavenged with fresh air in this manner, since entrance of EGR gas containing unburned fuel components and added fuel into the EGR cooler (83) can be prevented during abnormality detection, promotion of clogging of the EGR cooler (83) can be inhibited.

Description

INTERNAL COMBUSTION ENGINE CONTROL APPARATUS FOR EGR PASSAGE DIAGNOSIS
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The invention relates to a control apparatus for an internal combustion engine provided with an exhaust gas recirculation (EGR) device that recirculates to an intake passage a portion of exhaust gas discharged from a combustion chamber into an exhaust passage.
2. Description of the Related Art
[0002] EGR devices are provided in internal combustion engines (to be referred to as engines) installed in automobiles and the like for the purpose of reducing nitrogen oxides (NOx) contained in exhaust gas discharged from the combustion chambers. EGR devices recirculate a portion of the exhaust gas discharged into an exhaust passage to the intake passage through an EGR passage in the form of recirculated gas, and inhibits the formation of NOx by mixing with the air-fuel mixture to lower the combustion temperature.
[0003] When exhaust gas is recirculated (circulated as reflux) to the intake passage in this manner, the ignitability of the air-fuel mixture in the combustion chamber decreases, and since this leads to a decrease in engine output and engine operability, it is necessary to adjust the flow rate of the exhaust gas (EGR gas) recirculated to the intake passage according to the operating status of the engine. Therefore, in this type of EGR device, an EGR valve is provided in the EGR passage, and the amount of EGR gas recirculated to the intake passage is controlled by mis EGR valve.
(0004) In addition, in an engine provided with an EGR device, conventionally smoke is produced easily in diesel engines in particular due to a reduction in the amount of fresh air caused by introduction of EGR gas into the combustion chambers of the engine. In order to accommodate mis, an EGR cooler is provided in the EGR passage, and the production of smoke is inhibited as a result of increasing the amount of fresh air by reducing the volume of high-temperature EGR gas passing through the EGR passage by cooling. In addition, in this type of EGR device, in addition to providing a bypass passage that bypasses the EGR cooler of the EGR passage, a switching control valve is provided for adjusting the ratio of the amount of EGR gas flowing into the EGR passage and the bypass passage (see, for example, Japanese Patent Application Publication No. 2003-247459 (JP-A-2003-247459), Japanese Patent Application Publication No. 2006-299895 (JP-A-2006-299895) and Japanese Patent Application Publication No. 2006-291921 (JP-A-2006-291921)). [0005] However, in engines provided with an EGR device, soot, unburaed hydrocarbons (unhurried HC) and the like contained in EGR gas become adhered and deposited within the EGR cooler (heat exchange portion) as a result of long-term use, causing the EGR cooler to become clogged, thus resulting in the need for detection of abnormalities in EGR systems, including this type of clogging of the EGR passage. [0006] Although detection of clogging of the EGR passage (EGR passage abnormality detection) is carried out by, for example, opening the EGR passage on the side of the EGR cooler by controlling the switching control valve during vehicle deceleration, if the EGR passage is opened with EGR gas remaining in the passage immediately after deceleration, unburaed fuel components contained in the EGR gas are taken into the EGR cooler resulting in the possibility of promoting clogging of the EGR cooler. In addition, in engines provided with a fuel addition valve for adding fuel to the exhaust manifold, if the EGR passage is opened to detect clogging thereof when added fuel is present in the exhaust manifold, this can similarly result in the possibility of promoting clogging of the EGR cooler.
SUMMARY OF THE INVENTION
[0007] With the foregoing in view, the invention provides a control apparatus for an internal combustion engine provided with an EGR device that recirculates a portion of exhaust gas discharged from combustion chambers into an exhaust passage into an intake passage, and which realizes control capable of inhibiting promotion of clogging of an EGR cooler when detecting abnormalities in an EGR passage.
[0008] Therefore, according to one aspect thereof, the invention provides a control apparatus for an internal combustion engine provided with an EGR device having an EGR passage that recirculates to an intake passage a portion of exhaust gas discharged into an exhaust passage of an internal combustion engine, an EGR valve which is provided in the EGR passage and which adjusts an amount of exhaust gas recirculated from the exhaust passage to the intake passage, and an EGR cooler provided in the EGR passage, wherein the control apparatus is further provided with a switching device that controls opening and closing of the EGR passage and an abnormality detection device that detects abnormalities in the EGR device, and the abnormality detection device detects abnormalities in the EGR passage by opening the EGR passage by the control of the switching device when the inside of the exhaust passage upstream of the EGR cooler
(upstream side of EGR gas flow) has been scavenged after a criterion for detecting abnormalities in the EGR passage has been satisfied.
[0009] In addition, according to another aspect thereof, the invention provides a control apparatus for an internal combustion engine provided with an EGR device provided with an EGR passage that recirculates to an intake passage a portion of exhaust gas discharged into an exhaust passage of an internal combustion engine, an EGR valve which is provided in the EGR passage and which adjusts an amount of exhaust gas recirculated from the exhaust passage to the intake passage, an EGR cooler provided in the EGR passage, a bypass passage that bypasses the EGR cooler, and a control valve that adjusts the opening of the EGR passage and the opening of the bypass passage; wherein the control apparatus is further provided with an abnormality detection device for detecting abnormalities in the EGR device, and the abnormality detection device detects abnormalities in the EGR passage by opening the EGR passage on the side of the EGR cooler by the control of the control valve when the inside of the exhaust passage upstream of the EGR cooler (upstream side of EGR gas flow) has been scavenged after the criterion for detecting abnormalities in the EGR passage has been satisfied. [0010] According to the control apparatus for an internal combustion engine as described above, instead of detecting abnormalities in the EGR passage immediately after the criterion for detecting abnormalities in the EGR passage has been satisfied, since abnormalities are detected in the EGR passage by switching the EGR passage from closed to open after EGR gas and added fuel remaining in the exhaust passage upstream of die EGR cooler (and more specifically, in the exhaust manifold (which may also include a portion of the EGR passage)) have been scavenged with fresh air, entrance of
EGR gas containing unburned fuel components and added fuel into the EGR cooler can be prevented during EGR passage abnormality detection. As a result, promotion of clogging of the EGR cooler can be inhibited.
[0011] In addition, the amount of time from the time the criterion for detecting abnormalities in the EGR passage were satisfied until the time EGR gas and added fuel remaining in the exhaust passage upstream of the EGR cooler (and more specifically, in the exhaust manifold (which may also include a portion of the EGR passage)) are scavenged with fresh air b taken into consideration, and EGR passage abnormality detection is preferably carried out when an amount of time equivalent to the amount of time required for that scavenging (delay time) has elapsed. In this case, the delay time from the time abnormality detection criterion has been satisfied is acquired by, for example, determining by experimentation and calculation the amount of time for the concentration of fuel components in the exhaust passage upstream of the ECR cooler to decrease to a concentration that does not promote clogging of the EGR cooler, and the value (delay time) empirically determined on the basis of that result is set for the delay time.
[0012] In addition, EGR passage abnormality detection is also preferably carried out when the inside of the exhaust passage upstream of the EGR cooler has been scavenged with fresh air after the criterion for detecting abnormalities in the EGR passage has been satisfied, and die concentration of fuel components in the exhaust passage upstream of the EGR cooler (and more specifically, the exhaust manifold, for example) has decreased to equal to or less than a judgment threshold value. In this case, the judgment threshold value for fuel component concentration is acquired, for example, by determining by experimentation and calculation the relationship between the concentration of fuel components in gas passing through the EGR passage and the amount of fuel components adhered inside the EGR cooler, and the concentration (allowable value) of fuel components that does not promote clogging of the EQR cooler empirically determined on the basis of that relationship is set for the judgment threshold value.
[0013] In addition, a preferable specific configuration of a method for detecting abnormalities in an EGR passage consists of detecting the amount of clogging of the EGR passage based on the amount of change in the amount of intake air when the EGR valve is opened and when the EGR valve is closed while the EGR passage is opened, and then determining the presence of an abnormality in the EGR passage based on the results of detection.
[0014] In addition, another preferable specific configuration of a method for detecting abnormalities in an EGR passage, consists of detecting the amount of clogging of the EGR passage based on the amount of change in pressure within the intake manifold when the EGR valve is opened and when the EGR valve is closed while the EGR passage is opened, and then determining the presence of an abnormality in the EGR passage based on the results of detection.
[0015] Furthermore, the criterion for detecting abnormalities in the EGR passage as the criterion for detecting abnormalities in the EGR system preferably consist of, for example, when the vehicle is decelerating or when operating in an operating range of the internal combustion engine suitable for detection of abnormalities in the EGR passage, such as an operating state during which combustion status is favorable as is such after the internal combustion engine has warmed up. [0016] Here, EGR passage abnormality detection or bypass passage abnormality detection may be allowed to be carried out selectively in the invention corresponding to the operating range of the internal combustion engine. In providing an explanation of this configuration, first since there is increased susceptibility to clogging of the EGR cooler and production of smoke and the like in an operating range in which the combustion status of the internal combustion engine is poor (such as when the internal combustion engine is operating at high engine speeds, when operating at low atmospheric pressure when traveling at high altitudes, or when operating at low ambient temperatures), EGR passage abnormality detection may be made to not be carried out while bypass passage abnormality detection may be allowed to be carried out in operating ranges in which combustion status of the internal combustion engine is poor in consideration of these factors. In this case, when the criterion for detecting abnormalities in the bypass passage has been satisfied, clogging of the bypass passage is detected based on the amount of change in the amount of intake air or the amount of change in pressure in the intake manifold when the EGR valve is open and when it is closed while the bypass passage is open, and determination of an abnormality in the bypass passage is made based on the results of detection.
[0017] According to the invention, since EGR passage abnormality detection is carried out after a criterion for detecting abnormalities in the EGR passage has been satisfied when the inside of the exhaust passage upstream of the EGR cooler has been scavenged, entrance of EGR gas and added fuel into the EGR cooler during detection of abnormalities can be prevented. As a result, promotion of clogging of the EGR cooler can be inhibited.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The features, advantages, and technical and industrial significance of mis invention will be described in the following detailed description of example embodiments of the invention with reference to the accompanying drawings, in which like numerals denote like elements, and wherein: FIQ 1 is a schematic block diagram showing an example of a diesel engine to which an embodiment of the invention is applied;
FIG 2 is a block diagram showing the configuration of the control system such as an electronic control unit (ECU) shown in FIQ 1;
FIGS. 3A and 3B are schematic drawings for explaining a method for detecting the amount of clogging of an EGR passage in the embodiment;
FIG 4 is a drawing showing the flow of intake air when clogging has occurred in an EGR cooler in the method for detecting the amount of clogging of FIGS. 3A and 3B;
FIG. S is a flow chart showing a control routine for abnormality detection processing of the embodiment carried out in an ECU; and,
FIG 6 is a timing chart for abnormality detection processing of the embodiment carried out in an ECU.
DETAILED DESCRIPTION OF EMBODIMENTS [0019) The following provides an explanation of embodiments of the invention based on the drawings.
The following provides an explanation of the general configuration of a diesel engine to which an embodiment of the invention is applied with reference to FIG 1.
A diesel engine 1 of this example (to be referred to as "engine 1") is, for example, a common rail, fuel-injected 4-cylinder engine, and is composed by having for main components thereof a fuel supply system 2, combustion chambers 3, an intake system 6 and an exhaust system 7.
[0020] The fuel supply system 2 is provided with a supply pump 21, a common rail 22, injectors (fuel injection valves) 23, a shutoff valve 24, a fuel addition valve 25, a fuel pressure control valve 26, a fuel control valve 27, an engine fuel passage 28 and an added fuel passage 29.
[0021] The supply pump 21 pumps fuel from a fuel tank and after pressurizing the pumped fuel, supplies the pressurized fuel to the common rail 22 through the engine fuel passage 28. The common rail 22 has the function of a pressure accumulation chamber that maintains pressurized fuel supplied from the supply pump 21 at a prescribed pressure (pressure accumulation), and this fuel for which pressure has been maintained is distributed to each injector 23. The injectors 23 are electromagneα'cally driven on-off valves that open when a prescribed voltage has been applied and inject fuel into the combustion chambers 3. [0022] In addition, the supply pump 21 supplies a portion of the fuel pumped from the fuel tank to the fuel addition valve 25 through the added fuel passage 29. The fuel addition valve 25 is an electromagneticaUy driven on-off valve that opens when a prescribed voltage has been applied and adds fuel to an exhaust manifold 72 to be described later from exhaust ports 71 of the exhaust system 7. During an emergency, the shutoff valve 24 stops the supply of fuel by blocking the added fuel passage 29.
[0023] The intake system 6 is provided with an intake manifold 62 connected to intake ports formed in cylinder heads, and an intake pipe 64 composing an intake passage is connected to this intake manifold 62. In addition, an air cleaner 65, an air flow meter ' 32, an intercooler 61 to be described later, a throttle valve 63, an intake temperature sensor 33 and an intake pressure sensor 34 are arranged in order starting from the upstream side in the intake system 6. Furthermore, the intake manifold 62 composes a portion of the intake passage.
[0024] The exhaust system 7 is provided with an exhaust manifold 72 connected to the exhaust ports 71 formed in cylinder heads, and exhaust pipes 73 and 74 composing the exhaust passage are connected to this exhaust manifold 72. In addition, a catalyst device 4 is arranged in mis exhaust passage. Furthermore, the exhaust manifold 72 composes a portion of the exhaust passage.
[0025] The catalyst device 4 is provided with an NOx storage reduction (NSR) catalyst 41 and a diesel particulate-NOx reduction system (DPNR) catalyst 42.
[0026] The NSR catalyst 41 is an NOx occlusion-reduction catalyst having a composition consisting of, for example, an alumina (Al2Ch) support and an alkaline metal such as potassium (K), sodium (Na), lithium (Ii) or cesium (Cs)1 alkaline earth such as barium (Ba) or calcium (Ca), rare earth such as lanthanum (La) or yttrium (Y), or a precious metal such as platinum (Pt), loaded on the support
[0027] The NSR catalyst 41 occludes NOx when a large amount of oxygen is present in the exhaust gas, and reduces NOx to NO2 or NO followed by the release thereof when the oxygen concentration of the exhaust gas is low and there are large amounts of reducing components (such as unbumed fuel components (HC)) present in the exhaust gas. The NOx that have been released in the form OfNO2 or NO in this manner are further reduced to N2 by rapidly reacting with HC and CO present in the exhaust gas. In addition, the HC and CO are oxidized to H2O and CO2 as a result of reducing NO2 and NO. [0028] The DPNR catalyst 42 consists of, for example, loading an NOx occlusion-reduction catalyst onto a porous ceramic structure, and particulate matter (PM) present in exhaust gas is captured when the exhaust gas passes through the porous walls thereof. In addition, in the case the exhaust gas has a lean air-fuel ratio, NOx in the exhaust gas are occluded by the NOx occlusion-reduction catalyst, while in the case of a rich air-fuel ratio, occluded NOx are reduced and released. Moreover, a catalyst causing oxidation and combustion of captured PM (such as an oxidation catalyst having as a main component thereof a precious metal such as platinum) is loaded on the DPNR catalyst 42. [0029] A turbocharger (supercharger) 5 is provided in the engine 1. This turbocharger S is provided with a turbine wheel 52 and a compressor impeller 53 linked through a turbine. shaft 51. The compressor impeller 53 is arranged facing towards the inside of the intake pipe 64, and the turbine wheel 52 is arranged facing towards the inside of the exhaust pipe 73. This type of turbocharger 5 supercharges intake air by causing the compressor impeller 53 to rotate by utilizing exhaust flow (exhaust pressure) received by the turbine wheel 52. The turbocharger 5 of this example is a variable nozzle type of turbocharger, has a variable nozzle vane mechanism 54 provided on the side of the turbine wheel 52, and is able to adjust the boost pressure of the engine 1 by adjusting the opening of this variable nozzle vane mechanism 54.
[0030] The intercooler 61 is provided in the intake pipe 64 of the intake system 6 for forcibly cooling intake air heated by supercharging in the turbocharger S. The throttle valve 63 is provided downstream from this intercooler 61. The throttle valve 63 is an electronically controlled on-off valve capable of continuously adjusting the opening thereof, reduces the flow path area of intake air under prescribed conditions, and has the function of adjusting (reducing) the amount of intake air supplied.
[0031] In addition, an EOR device 8 is provided in this engine 1. The EGR device 8 lowers combustion temperature by resupplies a portion of the exhaust to the combustion chambers 3 by suitably recirculating to the intake system (intake passage) 6, thereby reducing the level of NOx emissions. The EGR device 8 is provided with an EGR passage 81 that connects the intake manifold 62 of the intake system 6 and the exhaust manifold 72 of the exhaust system 7. An EGR valve 82 and an EGR cooler 83 for cooling EGR gas passing (recirculating) through the EGR passage 81 are provided in the EGR passage 81, and the amount of EGR gas introduced from the exhaust system 7 to the intake system 6 (exhaust recirculation volume) can be adjusted by adjusting the opening of the EGR valve 82. [0032] Moreover, a bypass passage 84 that bypasses the EGR cooler 83 is provided in the EGR device 8. A switching control valve 85 for adjusting the opening of the EGR passage 81 and the opening of the bypass passage 84 is provided in the connection between the bypass passage 84 and the EGR passage 81 (connection on the downstream side of EGR gas flow). The ratio of the flow rates between the amount of EGR gas entering the EGR cooler 83 and the amount of EGR gas entering the bypass passage 84 can be arbitrarily adjusted by controlling this switching control valve 85. In addition, by controlling this switching control valve 85, the status of the flow of EGR gas can be set to a state in which EGR gas flows only to the EGR passage 81 while blocking the bypass passage 84 by fully opening the EGR passage 81 and fully closing the bypass passage 84, or to a state in which EGR gas flows only to the bypass passage 84 while blocking the EGR passage 81 by fully opening the bypass passage 84 and fully closing the EGR passage 81. This type of switching control valve 85 is controlled with an ECU
100 to be described later.
[0033] Various sensors are mounted at each site of the engine 1, and signals relating to environmental conditions at each site and the operating status of the engine 1 are output
[0034] For example, the air flow meter 32 is arranged upstream of the throttle valve 63 of the intake system 6, and outputs a detection signal corresponding to the amount of intake air. The intake temperature sensor 33 is arranged in the intake manifold 62, and outputs a detection signal corresponding to the temperature of intake air. The intake pressure sensor 34 is arranged in the intake manifold 62, and outputs a detection signal corresponding to intake air pressure.
[0035] An A/F sensor 35 is arranged in the exhaust pipe 74 downstream from the catalyst device 4 of the exhaust system 7, and outputs a detection signal corresponding to the oxygen concentration in the exhaust gas (exhaust A/F). An exhaust temperature sensor 36 is arranged in the exhaust pipe 74 downstream from the catalyst device 4 of me exhaust system 7, and outputs a detection signal corresponding to the temperature of exhaust gas (exhaust temperature). A rail pressure sensor 37 outputs a detection signal corresponding to the pressure of fuel accumulating in the common rail
22.
[0036] As shown in FIGL 2, the ECU 100 is provided with a central processing unit (CPU) 101, a read-only memory (ROM) 102, a random access memory (RAM) 103, a backup RAM 104 and the like. [0037] The ROM 102 stores various control programs and maps and the like referred to when executing the various control programs. The CPU 101 executes various types of arithmetic processing based on various control programs and maps stored in the ROM 102. In addition, the RAM 103 is a memory device for temporarily storing arithmetic processing results of the CPU 101 and data and the like input from various sensors, while the backup RAM 104 is a non- volatile memory device for storing data and the like to be saved when the engine 1 is stopped.
[0038] The above-mentioned ROM 102, CPU 101, RAM 103 and backup RAM 104 are mutually connected via a bus 107, and are connected to an input interface 105 and an output interface 106. {0039] A coolant temperature sensor 31, which outputs a detection signal corresponding to coolant temperature of the engine 1, the air flow meter 32, the intake temperature sensor 33, the intake pressure sensor 34, and A/F sensor 35, the exhaust temperature sensor 36, the rail pressure sensor 37, an accelerator depression amount sensor 38, which outputs a detection signal corresponding to the amount of depression of the accelerator pedal, and a crankshaft position sensor 39, which detects the rotating speed of the output shaft of the engine 1 in the form of the crankshaft (engine rotating speed), are connected to the input interlace 1 OS. On the other hand, the injectors 23, the shutoff valve 24, the fuel addition valve 25, the variable nozzle vane mechanism 54, the throttle valve 63, the EGR valve 82 and the switching control valve 85 are connected to the output interface 106.
[0040] The ECU 100 then executes various controls of the engine 1, including control of the amount of fuel injection, based on the outputs of each of the sensors described above. Moreover, the ECU 100 executes abnormality detection processing of the EOR device 8 described below.
Furthermore, the control apparatus for an internal combustion engine of the invention is realized by a program executed by the ECU 100.
[0041] Next, an explanation is provided of abnormality detection processing of the EGR device. In this example, abnormality detection of die EGR passage 81 and abnormality detection of the bypass passage 84 can be carried out selectively corresponding to the operating range of the engine 1.
First, an explanation is provided of abnormality detection of the EGR passage 81 (also referred to as EGR passage abnormality detection) with reference to FIGS. 3A, 3B and 4. [0042] EGR passage abnormality detection is carried out while the engine 1 is in operation by opening and closing the EGR valve 82 in the state in which the switching control valve 85 is switched to the EGR cooler 83 side (EGR passage 81 "open" position). More specifically, as shown hi FIQ 3A, the amount of intake air (fresh air volume) GNl is first measured based on the output signal of the air flow meter 32 with the EGR valve 82 fully open. Next, as shown in FIG 3B, the amount of intake air (fresh air volume) GN2 is measured based on the output signal of the air flow meter 32 with the EGR valve 82 fully closed.
[0043] Here, in the case the EGR passage 81 is not clogged and normal, the amount of intake air GNl as determined by the measurement of FIG 3A decreases. Namely, in the measurement of FIG 3A, since EGR gas is recirculated to the intake manifold 62 through the EGR passage 81, the amount of intake air (fresh air volume) is smaller than the measurement of FIG 3B (GNl < GN2), and the difference in the amounts of intake air between the two ΔGNa (ΔGNa - |0Nl-GN2l) increases. In contrast, as shown in FIG 4 (state in which the EGR valve 82 is fully open), if the EGR cooler 83 becomes clogged, for example, the amount of EGR gas recirculated to the intake manifold 62 decreases corresponding to the degree of the clogging, and the difference in the amounts of intake air ΔGNa as described above decreases. Moreover, if the EGR passage 81 becomes completely obstructed due to clogging of the EGR cooler 83, the difference in the amounts of intake air ΔGNa decreases to virtually zero (ΔGNa «
0).
[0044] Ih this manner, the degree of clogging of the EGR passage 81 can be detected from the difference in the amounts of intake air ΔGNa between the case in which the EGR valve 82 is fully open and the case in which it is fully closed in the state in which the bypass passage 84 is blocked and the EGR passage 81 is opeα By then comparing the difference in the amounts of intake air ΔGNa with a prescribed judgment threshold value Tha, the EGR passage 81 can be determined to be normal in the case the difference in the amounts of intake air ΔGNa exceeds the judgment threshold value Tha, or the EGR passage 81 can be determined to be abnormal in the case the difference in the amounts of intake air ΔGNa is equal to or less than the judgment threshold value Tha. Furthermore, the judgment threshold value Tha may be set in consideration of, for example, an on board diagnosis (OBD) defined value relating to exhaust emissions (PM NOx).
[0045] When detecting abnormalities in the EGR passage 81 as described above or abnormalities in the bypass passage 84 as described above, the throttle opening of the throttle value 63 and the opening of the variable nozzle vane mechanism 54 are fixed.
[0046] In addition, detection of abnormalities in the bypass passage 84 (bypass passage abnormality detection) can be similarly carried out by detecting the degree of clogging of the bypass passage 84 from the difference in the amounts of intake air ΔGNb (ΔGNb - |GN3-GN4l) between the case in which the EGR valve 82 is fully open (amount of intake air GN3) and the case in which the EGR valve 82 is fully closed (amount of intake air GN4) with the EGR passage 81 blocked and the bypass passage 84 open. By then comparing the difference in the amounts of intake air ΔGNb with a prescribed judgment threshold value Thb, the bypass passage 84 can be determined to be normal in the case the difference in the amounts of intake air ΔGNb exceeds the judgment threshold value Thb, or can be determined to be abnormal in the case the difference in the amounts of intake air ΔGNb is equal to or less than the judgment threshold value Thb.
[0047] Furthermore, the judgment threshold value Thb used for bypass passage abnormality detection in this manner may be set in the same manner as in the case of EGR passage abnormality detection, or may be individually set to conforming values in consideration of OBD defined values relating to exhaust emissions (FMNOx).
[0048] Next, a specific example of the abnormality determination processing of this example is explained with reference to the flow chart of FIG S and the timing chart of FTG 6. The processing routine of FIG 5 is repeatedly executed at prescribed time intervals (such as every several msec to every several tens of msec) in the ECU 100.
[0049] First, in Step STlOl, a determination is made as to whether or not the abnormality detection criterion of the EGR device 8 (EGR system) has been satisfied. More specifically, when a determination is made as to whether or not a vehicle is decelerating and the vehicle is determined to be decelerating, the abnormality detection criterion is determined to be satisfied and processing proceeds to Step STl 02. Processing returns in the case the result of the determination of Step STlOl is determined to be negative. Here, in this example, the addition of fuel from the fuel addition valve 25 to the exhaust manifold 72 stops simultaneous to the start of vehicle deceleration as shown in FIG 6. In addition, the EGR passage 81 is temporarily fully closed by controlling the switching control valve 85 when the abnormality detection criterion has been satisfied as a result of the start of vehicle deceleration.
[0050] Furthermore, an example of a determination criterion in Step STlOl, or in other words, an abnormality detection criterion, is "after the engine 1 has warmed up". [0051] In Step STl 02, a determination is made as to whether or not a prescribed delay time DT has elapsed from the time abnormality detection criterion have been satisfied, and processing proceeds to Step STl 03 when that delay time DT has elapsed (when the result of the determination of Step STl 02 has become positive). The delay time DT used in the determination processing of this step STl 02 is set in consideration of the time required for EGR gas and added fuel remaining in the exhaust manifold 72 upstream of the EGR cooler 83 (and which may include a portion of the EGR passage 81) to be scavenged with fresh air at the time abnormality detection criterion has been satisfied. More specifically, the time for the concentration of fuel components in the exhaust manifold 72 to decrease to equal to or lower than an allowed value (concentration of fuel components able to inhibit promotion of clogging of the EGR cooler 83) as a result of scavenging with fresh air is extracted in advance by experimentation and calculation, and the value (time) that conforms to those results is set as the delay time DT. This delay time DT is stored in the ROM 102 of the ECU 100. [0052] Next, in Step ST103, a determination is made as to whether the detection range is the detection range of the EGR passage 81 (to be referred to as the EGR passage detection range), and in the case the result of that determination is positive, processing proceeds to Step ST104. In the case the result of the determination of Step S 103 is negative, processing proceeds to Step STl 06. [0053] Here, in providing an explanation of the EGR passage detection range, in an operating range in which combustion status of the engine 1 is poor, such as when the engine 1 is operating at high engine speeds, when operating at low atmospheric pressure when traveling at high altitudes, or when operating at low ambient temperatures, since there is increased susceptibility to the occurrence of clogging or smoking of the EGR cooler 83; abnormality detection of die EGR passage 81 is not carried out in such operating ranges, while detection of the amount of clogging and abnormalities in the EGR cooler 81 as described below is carried out during an operating range in which combustion status is favorable.
[0054] More specifically, in the case the result of the determination of Step STl 03 is positive and the operating status of the engine 1 is in the EGR passage detection range, the EGR passage 81 is opened (the bypass passage 84 is closed) under the control of the switching control valve 85, and the EGR passage 81 is connected between the exhaust manifold 72 and the intake manifold 62 (Step STl 04). While in this state, the EGR valve 82 is fully opened for a fixed period of time to extract the amount of intake air GNl as shown in FIG 6, after which the EGR valve 82 is fully closed for a fixed period of time to extract the amount of intake air GN2, followed by calculating the amount of change between the amount of intake air GNl when fully open and the amount of intake air GN2 when fully closed (difference in amounts of intake air ΔGNa [ΔGNa = |GNl-GN2|]: equivalentto degree ofclogging ofthe EGRpassage 81). The difference in amounts of intake air ΔGNa calculated in this manner is then compared with the above-mentioned judgment threshold value Tha, and in the case the difference in amounts of intake air ΔGNa exceeds the judgment threshold value Tha, the EGR passage 81 is determined to be normal, while if the difference in amounts of intake air ΔGNa is equal to or less than the judgment threshold value Tha, the EGR passage 81 is determined to be abnormal (Step STl 05).
[0055] On the other hand, in the case the result of the determination of Step STl 03 is negative (case of not being in the EGR passage detection range), abnormality detection is carried out on the bypass passage 84. More specifically, the bypass passage 84 is opened (the EGR passage 81 is closed) under the control of the switching control valve 85, and the bypass passage 84 is connected between the exhaust manifold 72 and the intake manifold 62 (Step STl 06). While in this state, the EGR valve 82 is fully opened for a fixed period of time to extract the amount of intake air GN3, after which the EGR valve 82 is fully closed for a fixed period of time to extract the amount of intake air GN4, followed by calculation of the amount of change between the amount of intake air GN3 when fully open and the amount of intake air GN4 when fully closed (difference in amounts of intake air ΔGNb [ΔGNb = I GN3-GN41 ]: equivalent to degree of clogging of bypass passage 84). The difference in amounts of intake air ΔGNb calculated in this manner is then compared with the above-mentioned judgment threshold value Thb, and in the case the difference in amounts of intake air ΔONb exceeds the judgment threshold value Thb, the bypass passage 84 is determined to be normal, while if the difference in amounts of intake air ΔGNb is equal to or less than die judgment threshold value Thb, the bypass passage 84 is determined to be abnormal (Step STl 07). [0056] As has been described above, according to this example, since the degree of clogging of the EGR passage 81 is detected and diagnosed for the presence of an abnormality in the EGR passage 81 at the time a prescribed delay time DT has elapsed, or in other words, at the time when EGR gas and added fuel remaining in the exhaust manifold 72 upstream of the EGR cooler 83 (upstream side of the flow of EGR gas) has been scavenged with fresh air, after the abnormality detection criterion of the EGR device 8 has been satisfied, entrance of EGR gas containing υnbumed fuel components and added fuel into the EGR cooler 83 can be prevented during abnormality detectioa As a result, promotion of clogging of the EGR cooler 83 can be inhibited.
[0057] Furthermore, abnormalities in the EGR device 8 may also be detected in the example described above by processing consisting of detecting the degree of clogging of the EGR passage 81 on the side of the EGR cooler 83 (abnormality detection) several times after the abnormality detection criterion of the EGR device 8 has been satisfied, and then switching the switching control valve 85 and detecting clogging of the bypass passage 84 (abnormality detection) several times. {0058} The following provides an explanation of another embodiment
Although clogging of the EGR passage 81 (or clogging of the bypass passage 84) is detected at the time an amount of time required for scavenging EGR gas and added value within the exhaust manifold 72 with fresh air (delay time DT) has elapsed after the abnormality detection criterion has been satisfied in the previously explained embodiment, the invention is not limited thereto, but rather as shown in FIG. 6, for example, after the abnormality detection criterion has been satisfied, clogging of the EGR passage 81 (or clogging of the bypass passage 84) may be detected at the time the concentration of fuel components in (he exhaust manifold 72 has decreasedto a prescribed judgment threshold value Nth or lower. [0059] In this case, the judgment threshold value Nth for the concentration of fuel components in the exhaust manifold 72 can be acquired experimentally or by calculation from the relationship between the fuel component concentration of gas passing through the EGR passage 81 and the amount of fuel components adhered inside the EGR cooler 83, and then using the empirically determined value for the fuel component concentration that does not promote clogging of the EGR cooler 83 based on that relationship for the judgment threshold value Nth. Furthermore, the fuel component concentration in the exhaust manifold 72 may be determined based on the oxygen concentration detected with the A/F sensor 35, or a sensor for detecting oxygen concentration in the exhaust manifold 72 may be provided, and fuel component concentration may be detected based on the output from that sensor.
[0060] Although the degree of clogging of the EGR passage 81 (or bypass passage 84) is detected in the above example by measuring the amount of change in the difference in quantities of intake air (intake air volume difference) between the amount of intake air when the EGR valve 82 is fully open and the amount of intake air when the EGR valve is fully closed when detecting abnormalities in the EGR device 8, the invention is not limited thereto, but rather the degree of clogging of the EGR passage 81 (or the bypass passage 84) may be detected based on the amount of change in the pressure within the intake manifold 62 (which may also be referred to as intake manifold pressure), an explanation of which is provided below.
[0061] First, in FIGS. 3 A and 3B (case in which the EGR passage 81 is normal), for example, when the throttle opening of the throttle valve 63 is constant (fixed), the absolute value of the intake manifold pressure (negative pressure) during the intake stroke of the engine 1 differs between the case in which the EGR valve 82 is fully open and the case in which it is fully closed, with that in the case the EGR valve 82 is fully open being smaller.
[0062] Namely, in the case of the EGR valve 82 is fully open (intake manifold pressure PINl), the absolute valve of the intake manifold pressure decreases by an amount corresponding to (he amount of EGR gas that recirculates to the intake manifold 62 in comparison with the case in which the EOR valve 82 is fully closed (intake manifold pressure PIN2) ( I PINl I <| PIN21 ), and the amount of change in intake manifold pressure between the two ΔPIN (ΔPIN = I PINl -PIN21 ) increases. In contrast, as shown in FIG 4, if the EGR cooler 83 becomes clogged, for example, the amount of EGR gaa recirculating to the intake manifold 62 decreases by an amount corresponding to the degree of clogging, and the amount of change in intake manifold pressure ΔPIN becomes smaller. Moreover, if the EGR passage 81 becomes completely obstructed due to clogging of the EGR cooler 83, the difference in the amounts of intake air PIN decreases to virtually zero (ΔPIN * 0). [0063] In this manner, the degree of clogging of the EGR passage 81 can be detected from the amount of change in intake manifold pressure ΔPIN between the case in which the EGR valve 82 is fully open and the case in which it is fully closed in the state in which the bypass passage 84 is blocked and the EGR passage 81 is open. Thus, similar to the case of detection using the difference in amounts of intake air ΔGNa described above, by comparing the amount of change in intake manifold pressure ΔPIN with a prescribed judgment threshold value, the EGR passage 81 can be determined to be normal in the case the amount of change in intake manifold pressure ΔPIN exceeds the judgment threshold value, while the EGR passage 81 can be determined to be abnormal in the case the amount of change in intake manifold pressure ΔPIN is equal to or less than the judgment threshold value. Furthermore, intake manifold pressure can be measured based on an output signal from an intake pressure sensor 34 arranged in the intake manifold 62.
[0064] In addition, since abnormalities in the bypass passage 84 can also be detected by detecting the degree of clogging of the bypass passage 84 from the amount of change b intake manifold pressure ΔPIN between the case in which the EGR valve 82 is fully open and the case in which it is fully closed with the EGR passage 81 blocked and the bypass passage 84 blocked, the bypass passage 84 can be determined to be normal or abnormal based on the detection result
[0065] In the above-mentioned example indicates an example of applying the control apparatus of the invention to a fuel-injected 4-cylinder diesel engine, the invention is not limited thereto, but rather can also be applied to, for example, a fuel-injected 6-cylinder diesel engine or other diesel engine having an arbitrary number of cylinders. In addition, the invention is not limited to a fiiel-injected diesel engine, but rather can also be applied to the control of other types of diesel engines as well. Moreover, the invention is not limited to diesel engines, but rather can be applied to the control of gasoline engines as well.

Claims

1. A control apparatus for an internal combustion engine provided with an EGR device having an EGR passage that recirculates to an intake passage a portion of exhaust gas discharged into an exhaust passage of an internal combustion engine, an EGR valve which is provided in the EGR passage and which adjusts an amount of exhaust gas recirculated from the exhaust passage to the intake passage, and an EGR cooler provided in the EGR passage, the control apparatus being characterized by further comprising: a switching device that controls opening and closing of the EGR passage; and an abnormality detection device that detects abnormalities in the EGR device, wherein the abnormality detection device detects abnormalities in the EGR passage by opening the EGR passage by the control of the switching device when the inside of the exhaust passage upstream of the EGR cooler has been scavenged after a criterion for detecting abnormalities in the EGR passage has been satisfied.
2. A control apparatus for an internal combustion engine provided with an EGR device provided with an EGR passage that recirculates to an intake passage a portion of exhaust gas discharged into an exhaust passage of an internal combustion engine, an EGR valve which is provided in the EGR passage and which adjusts an amount of exhaust gas recirculated from the exhaust passage to the intake passage, an EGR cooler provided in the EGR passage, a bypass passage that bypasses the EGR cooler, and a control valve mat adjusts the opening of the EGR passage and the opening of the bypass passage, the control apparatus being characterized by further comprising: an abnormality detection device for detecting abnormalities in the EGR device, wherein the abnormality detection device detects abnormalities in the EGR passage by opening the EGR passage on the side of the EGR cooler by the control of the control valve when the inside of the exhaust passage upstream of the EGR cooler has been scavenged after the criterion for detecting abnormalities in the EGR passage has been satisfied.
3. The control apparatus for an internal combustion engine according to claim 1 or 2, characterized in that the abnormality detection device detects abnormalities in the EGR passage when a prescribed delay time has elapsed after the criterion for detecting abnormalities in the EGR passage has been satisfied.
4. The control apparatus for an internal combustion engine according to claim 1 or 2, characterized in that the abnormality detection device detects abnormalities in the EGR passage when a concentration of fuel components in the exhaust passage upstream of the EGR cooler has decreased to equal to or less than a judgment threshold value after the criterion for detecting abnormalities in the EGR passage has been satisfied.
5. The control apparatus for an internal combustion engine according to any one of claims 1 through 4, characterized in that the abnormality detection device detects a degree of clogging of the EGR passage based on an amount of change in amounts of intake air between a case in which the EGR valve is opened and a case in which it the EGR valve is closed when the EGR passage is opened, and determines an abnormality in the EGR passage based on the detection result
6. The control apparatus for an internal combustion engine according to any one of claims 1 through 4, characterized hi that the abnormality detection device detects a degree of clogging of the EGR passage based on an amount of change in pressure in an intake manifold between a case in which the EGR valve is opened and the case in which the EGR valve is closed when the EGR passage is opened, and determines an abnormality in the EGR passage based on the detection result.
7. The control apparatus for an internal combustion engine according to any one of claims 2 through 6, characterized in that the abnormality detection device selectively detects an abnormality in the EGR passage or an abnormality in the bypass passage corresponding to an operating range of the internal combustion engine.
8. The control apparatus for an internal combustion engine according to claim 7, characterized in that in a case of detecting an abnormality in the bypass passage, the abnormality detection device detects a degree of clogging of the bypass passage based on an amount of change in amounts of intake air between a case in which the EGR valve is opened and a case in which the EGR valve is closed, with the bypass passage being opened by the control of the control valve, and determines an abnormality in the bypass passage based on the detection result
9. The control apparatus for an internal combustion engine according to claim 7, characterized in that in a case of detecting an abnormality in the bypass passage, the abnormality detection device detects a degree of clogging of the bypass passage based on an amount of change in pressure in the intake manifold between a case in which the EGR valve is opened and a case in which the EGR valve is closed, with the bypass passage being opened by the control of the control valve, and determines an abnormality in the bypass passage based on the detection results.
10. The control apparatus for an internal combustion engine according to claim 1 or 2, characterized in that the criterion for detecting the abnormalities is based on operation during deceleration of a vehicle in which the internal combustion engine is installed.
11. The control apparatus for an internal combustion engine according to claim 1 or 2, characterized in that the criterion for detecting the abnormalities is based on operation after the internal combustion engine has warmed up.
PCT/IB2009/006393 2008-07-29 2009-07-29 Internal combustion engine control apparatus for egr passage diagnosis Ceased WO2010013123A1 (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2492770A (en) * 2011-07-11 2013-01-16 Gm Global Tech Operations Inc Method and apparatus for operating an exhaust gas recirculation system
WO2014188246A1 (en) * 2013-05-20 2014-11-27 Toyota Jidosha Kabushiki Kaisha Control apparatus and control method for internal combustion engine
US9127606B2 (en) 2010-10-20 2015-09-08 Ford Global Technologies, Llc System for determining EGR degradation
US9476387B2 (en) 2011-05-13 2016-10-25 Ford Global Technologies, Llc System for determining EGR cooler degradation

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5674323B2 (en) * 2010-02-16 2015-02-25 レノボ・イノベーションズ・リミテッド（香港） Shield structure
JP5775509B2 (en) * 2012-12-10 2015-09-09 本田技研工業株式会社 Control device for internal combustion engine
JP6225701B2 (en) * 2013-12-27 2017-11-08 スズキ株式会社 EGR device failure diagnosis device

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0843084A2 (en) * 1996-11-14 1998-05-20 Toyota Jidosha Kabushiki Kaisha Combustion engine with EGR apparatus
JP2003247459A (en) * 2002-02-20 2003-09-05 Toyota Motor Corp EGR mechanism for internal combustion engine
DE10322535A1 (en) * 2002-05-20 2004-02-12 Denso Corp., Kariya Exhaust gas recirculation system with a cooler
DE102004041767A1 (en) * 2004-08-28 2006-03-02 Robert Bosch Gmbh Method and device for operating an internal combustion engine with exhaust gas recirculation
JP2006299895A (en) * 2005-04-20 2006-11-02 Honda Motor Co Ltd EGR device for internal combustion engine

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0843084A2 (en) * 1996-11-14 1998-05-20 Toyota Jidosha Kabushiki Kaisha Combustion engine with EGR apparatus
JP2003247459A (en) * 2002-02-20 2003-09-05 Toyota Motor Corp EGR mechanism for internal combustion engine
DE10322535A1 (en) * 2002-05-20 2004-02-12 Denso Corp., Kariya Exhaust gas recirculation system with a cooler
DE102004041767A1 (en) * 2004-08-28 2006-03-02 Robert Bosch Gmbh Method and device for operating an internal combustion engine with exhaust gas recirculation
JP2006299895A (en) * 2005-04-20 2006-11-02 Honda Motor Co Ltd EGR device for internal combustion engine

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9127606B2 (en) 2010-10-20 2015-09-08 Ford Global Technologies, Llc System for determining EGR degradation
US9476387B2 (en) 2011-05-13 2016-10-25 Ford Global Technologies, Llc System for determining EGR cooler degradation
GB2492770A (en) * 2011-07-11 2013-01-16 Gm Global Tech Operations Inc Method and apparatus for operating an exhaust gas recirculation system
WO2014188246A1 (en) * 2013-05-20 2014-11-27 Toyota Jidosha Kabushiki Kaisha Control apparatus and control method for internal combustion engine

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