WO2022024551A1 - Système d'egr - Google Patents

Système d'egr Download PDF

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Publication number
WO2022024551A1
WO2022024551A1 PCT/JP2021/021502 JP2021021502W WO2022024551A1 WO 2022024551 A1 WO2022024551 A1 WO 2022024551A1 JP 2021021502 W JP2021021502 W JP 2021021502W WO 2022024551 A1 WO2022024551 A1 WO 2022024551A1
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WO
WIPO (PCT)
Prior art keywords
egr
valve
passage
engine
failure
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Application number
PCT/JP2021/021502
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English (en)
Japanese (ja)
Inventor
衛 吉岡
海翔 曹
崇 別所
伸二 河井
Original Assignee
愛三工業株式会社
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Publication of WO2022024551A1 publication Critical patent/WO2022024551A1/fr

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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
    • F02D43/00—Conjoint electrical control of two or more functions, e.g. ignition, fuel-air mixture, recirculation, supercharging or exhaust-gas treatment
    • 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
    • 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
    • F02M26/45—Sensors specially adapted for EGR systems
    • F02M26/46—Sensors specially adapted for EGR systems for determining the characteristics of gases, e.g. composition
    • F02M26/47—Sensors specially adapted for EGR systems for determining the characteristics of gases, e.g. composition the characteristics being temperatures, pressures or flow rates
    • 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

Definitions

  • the technique disclosed herein relates to an EGR system configured to allow a portion of the exhaust gas discharged from the engine to the exhaust passage as EGR gas to flow through the EGR passage to the intake passage and return to the engine. Relates to an EGR system configured to diagnose a failure of that system.
  • the exhaust gas recirculation device (EGR device) of this technology is an EGR control valve (EGR gas flow rate) that controls the exhaust gas circulation amount (EGR gas flow rate) in the exhaust gas recirculation passage (EGR passage) that connects the exhaust passage and the intake passage of the engine. It is provided with an EGR valve), an EGR cooler that cools the EGR gas, a bypass passage that bypasses the EGR cooler, and a switching control valve (bypass valve) that controls the inflow of the EGR gas into the bypass passage.
  • EGR control valve EGR gas flow rate
  • EGR passage exhaust gas recirculation passage
  • this EGR device is detected by the temperature detecting means provided on the downstream side of the bypass valve, the operating means for switching and operating the bypass valve at a predetermined time, and the temperature detecting means before and after the switching operation of the bypass valve by the operating means. Further provided with a diagnostic means for diagnosing a cooling abnormality of the EGR cooler based on the temperature difference.
  • Patent Document 1 can diagnose a cooling abnormality of the EGR cooler, it particularly shows how to control the introduction of EGR gas into the engine when the occurrence of the cooling abnormality is determined. Not. Therefore, it was not possible to properly deal with the cooling abnormality. As a result, if EGR is performed even though a cooling abnormality has occurred, there is a risk that condensed water will be generated in the EGR passage due to insufficient warming up, or that the EGR passage will be melted due to overheating. there were.
  • This disclosure technique was made in view of the above circumstances, and the purpose is to generate condensed water in the EGR cooler and the EGR passage downstream of the bypass passage even if the bypass valve provided in the bypass passage fails. It is an object of the present invention to provide an EGR system capable of suppressing melting damage of an EGR passage.
  • the aspect of the present invention is configured so that a part of the exhaust gas discharged from the engine to the exhaust passage is passed as EGR gas to the intake passage through the EGR passage and returned to the engine.
  • an EGR valve for adjusting the flow rate of EGR gas in the EGR passage and an EGR cooler for exchanging heat between the EGR gas and the cooling water of the engine to cool the EGR gas flowing in the EGR passage.
  • EGR temperature detecting means for detecting wall temperature or EGR gas temperature
  • bypass valve failure diagnostic means for diagnosing a bypass valve failure based on at least the operating state of the bypass valve and the detected temperature. It is intended that the EGR valve control means for controlling the EGR valve according to the failure diagnosis result by the bypass valve failure diagnosis means is provided.
  • the bypass valve when the bypass valve is normally opened, the pressure loss of the bypass passage is small, so that most of the EGR gas flowing from the exhaust passage to the EGR passage flows to the bypass passage, and the rest is the EGR cooler. Flow to. Then, these two flows merge in the downstream EGR passage, flow to the intake passage, and are returned to the engine. Therefore, even if a high-temperature EGR gas flows from the exhaust passage to the EGR passage, a part of the EGR gas is heat-exchanged by the EGR cooler to lower the temperature, and then merges with the EGR gas flowing through the bypass passage to increase the temperature. As the temperature drops, the EGR gas lowered to an appropriate temperature flows to the intake passage through the downstream EGR passage.
  • the bypass valve failure diagnosis means diagnoses the failure of the bypass valve based on at least the operating state of the bypass valve and the temperature of the wall of the EGR passage or the temperature of the EGR gas detected by the EGR temperature detecting means. Then, the EGR valve control means controls the EGR valve according to the failure diagnosis result by the bypass valve failure diagnosis means. Therefore, since the EGR valve is controlled according to the diagnosis result of the failure of the bypass valve, it is possible to prevent the high temperature EGR gas from unnecessarily flowing to the downstream EGR passage.
  • the diagnosis result by the bypass valve failure diagnosis means is a failure of the bypass valve open failure (a failure with the bypass valve open).
  • the EGR valve is controlled to an opening of less than a predetermined value, and the diagnosis result is a failure to close the bypass valve (a failure with the bypass valve closed). Underneath, it is preferable to control the EGR valve to be fully closed.
  • the EGR control means sets the EGR valve to a predetermined value or less. Since the opening degree is controlled, the flow rate of the high temperature EGR gas flowing to the downstream EGR passage is suppressed, and the temperature of the EGR gas flowing to the downstream EGR passage is reduced.
  • the diagnosis result by the bypass valve failure diagnosis means is a closed failure of the bypass valve
  • the EGR control means controls the EGR valve to be fully closed under the valve opening condition of the bypass valve. The flow of EGR gas is cut off, and the EGR gas whose temperature has dropped due to heat exchange by the EGR cooler does not flow to the downstream EGR passage.
  • the cooling water temperature detecting means for detecting the temperature of the cooling water of the engine is further provided, and the bypass valve failure diagnosis means is provided. It is preferable to diagnose the failure of the bypass valve by comparing the temperature of the cooling water detected after starting the engine with the temperature of the wall of the EGR passage or the temperature of the EGR gas detected by the EGR temperature detecting means.
  • the bypass valve failure diagnosis means is the temperature of the cooling water detected by the cooling water temperature detecting means after the engine is started.
  • the failure of the bypass valve is diagnosed by comparing the temperature of the wall of the EGR passage detected by the EGR temperature detecting means or the temperature of the EGR gas.
  • the cooling water temperature detecting means is usually used to control the engine. Therefore, in order to diagnose the failure of the bypass valve, it is not necessary to provide a special detecting means other than the EGR temperature detecting means.
  • bypass valve failure diagnosis means corrects the temperature of the detected cooling water according to the opening degree of the EGR valve.
  • the bypass valve failure diagnosis means corrects the temperature of the detected cooling water according to the opening degree of the EGR valve.
  • the temperature of the EGR gas flowing through the EGR passage changes according to the flow rate of the EGR gas, that is, the opening degree of the EGR valve. Therefore, the temperature of the wall of the EGR passage or the temperature of the cooling water compared with the temperature of the EGR gas is corrected according to the flow rate of the EGR gas.
  • an EGR valve failure diagnosis means for diagnosing a failure of the EGR valve and an engine output for adjusting the output of the engine.
  • an engine control means for controlling the output adjusting means.
  • the diagnosis result by the bypass valve failure diagnosis means is the open failure of the bypass valve, and the EGR valve failure diagnosis means.
  • the engine control means controls the output adjusting means in order to limit the output of the engine. Therefore, in the case of an open failure in which the EGR valve cannot be controlled (double failure) in addition to the open failure of the bypass valve, the output of the engine is limited by the output adjusting means, so that the engine can be operated normally. It disappears.
  • the configuration of the EGR system in addition to the effect of the configuration of the above (1) or (2), the configuration of the EGR system can be simplified to the extent that no special detection means needs to be provided. Product costs can be reduced.
  • FIG. 1 shows a gasoline engine system of this embodiment (hereinafter, simply referred to as “engine system”) by a schematic configuration diagram.
  • the engine system mounted on the automobile includes an engine 1 having a plurality of cylinders.
  • the engine 1 is a 4-cylinder, 4-cycle reciprocating engine and includes well-known configurations such as a piston and a crankshaft.
  • the engine 1 is provided with an intake passage 2 for introducing intake air into each cylinder and an exhaust passage 3 for deriving exhaust gas from each cylinder of the engine 1.
  • the intake passage 2 is provided with an air cleaner 9, a throttle device 4, and an intake manifold 5 from the upstream side thereof.
  • this engine system comprises a high pressure loop type exhaust gas recirculation device (EGR device) 11.
  • EGR device high pressure loop type exhaust gas recirculation device
  • the throttle device 4 is arranged in the intake passage 2 upstream of the intake manifold 5, and by driving the butterfly type throttle valve 4a to open and close with a variable opening according to the accelerator operation of the driver, the amount of intake air flowing through the intake passage 2 Is designed to be adjusted.
  • the throttle device 4 corresponds to an example of the output adjusting means in the disclosed technique.
  • the intake manifold 5 is mainly composed of a resin material and is arranged in the intake passage 2 directly upstream of the engine 1.
  • One surge tank 5a into which the intake air is introduced and the intake air introduced in the surge tank 5a are used in the engine 1. It includes a plurality of (four) branch pipes 5b branched from the surge tank 5a for distribution to each cylinder.
  • the exhaust manifold 6 and the catalyst 7 are provided in the exhaust passage 3 in order from the upstream side thereof. For example, a three-way catalyst is built in the catalyst 7 in order to purify the exhaust gas.
  • the engine 1 is provided with a fuel injection device (not shown) for injecting fuel corresponding to each cylinder.
  • the fuel injection device is configured to inject fuel supplied from a fuel supply device (not shown) into each cylinder of the engine 1.
  • a combustible air-fuel mixture is formed by the fuel injected from the fuel injection device and the intake air introduced from the intake manifold 5.
  • the engine 1 is provided with an ignition device (not shown) corresponding to each cylinder.
  • the igniter is configured to ignite the combustible mixture in each cylinder.
  • the combustible air-fuel mixture in each cylinder explodes and burns due to the ignition operation of the ignition device, and the exhaust gas after combustion is discharged from each cylinder to the outside via the exhaust manifold 6 and the catalyst 7.
  • the piston (not shown) moves up and down in each cylinder, and the crankshaft (not shown) rotates to obtain power to the engine 1.
  • the EGR system of this embodiment includes a high pressure loop type EGR device 11.
  • the EGR device 11 is configured to flow a part of the exhaust gas discharged from each cylinder of the engine 1 to the exhaust passage 3 as an exhaust gas recirculation gas (EGR gas) to the intake passage 2 and return the exhaust gas to each cylinder of the engine 1.
  • the EGR device 11 includes an exhaust gas recirculation passage (EGR passage) 12 for flowing EGR gas from the exhaust passage 3 to the intake passage 2, and an exhaust gas recirculation cooler (EGR cooler) 13 for cooling the EGR gas flowing through the EGR passage 12.
  • EGR passage exhaust gas recirculation passage
  • EGR cooler exhaust gas recirculation cooler
  • the exhaust gas recirculation valve (EGR valve) 14 provided downstream from the EGR cooler 13 in order to adjust the flow rate of the EGR gas flowing through the EGR passage 12, and the EGR gas flowing through the EGR passage 12 are distributed to each cylinder of the engine 1. Therefore, an exhaust gas recirculation gas distributor (EGR gas distributor) 15 made of a resin that distributes EGR gas to each branch pipe 5b of the intake manifold 5 is provided.
  • the EGR gas distributor 15 is provided in the EGR passage 12 downstream of the EGR cooler 13 and the EGR valve 14.
  • the EGR passage 12 includes an inlet 12a and an outlet 12b.
  • the inlet 12a of the EGR passage 12 is connected to the exhaust passage 3 upstream of the catalyst 7, and the outlet 12b of the passage 12 is connected to the EGR gas distributor 15.
  • the EGR gas distributor 15 constitutes the final stage of the EGR passage 12.
  • the EGR valve 14 is provided adjacent to the EGR cooler 13 downstream of the EGR cooler 13.
  • the EGR valve 14 is configured to drive the valve body using a step motor as a drive source.
  • the EGR cooler 13 is configured to allow the cooling water of the engine 1 to flow.
  • the EGR cooler 13 is configured to exchange heat between the EGR gas and the cooling water of the engine 1 in order to cool the EGR gas flowing through the EGR passage 12.
  • the detailed description of the configuration of the EGR cooler 13 will be omitted.
  • the EGR cooler 13 is provided with a bypass passage 16.
  • the bypass passage 16 is a passage for bypassing a part of the EGR gas flowing to the EGR cooler 13 in the EGR passage 12.
  • the bypass passage 16 is provided with a bypass valve 17 for opening and closing the passage 16.
  • the EGR gas distributor 15 is mainly composed of a resin material, has a horizontally long shape as a whole, and has a plurality of branch pipes of the intake manifold 5 in the longitudinal direction (left-right direction in FIG. 1) as shown in FIG. Arranged so as to cross 5b.
  • the EGR gas distributor 15 is branched from one gas chamber 15a in which the EGR gas introduced from the outlet 12b of the EGR passage 12 collects, and the gas chamber 15a, and the EGR is branched from the gas chamber 15a to each branch pipe 5b. It includes a plurality (4) gas distribution passages 15b for distributing gas.
  • bypass valve 17 is attached to the housing of the EGR cooler 13 and is configured to open and close the bypass passage 16 integrally with the housing.
  • the bypass valve 17 is configured to allow engine cooling water to flow.
  • the bypass valve 17 is configured to operate in response to a change in the temperature of the cooling water.
  • the bypass valve 17 includes an actuator configured to close the valve body from the open state when the temperature of the cooling water exceeds a predetermined value.
  • the actuator can be configured, for example, with a thermowax.
  • a detailed description of the configuration of the bypass valve 17 will be omitted.
  • the bypass valve 17 is opened by an actuator to open the bypass passage 16 at a low temperature, and closed by an actuator to shut off the bypass passage 16 at a high temperature. That is, in this embodiment, when the temperature of the cooling water is lower than a predetermined value, the bypass valve 17 is not warmed and is opened.
  • the bypass valve 17 opens, most of the EGR gas flowing from the exhaust passage 3 to the EGR passage 12 flows to the bypass passage 16, and the remaining EGR gas flows to the EGR cooler 13, respectively downstream of the EGR cooler 13. Meet at EGR passage 12.
  • the merged EGR gas further flows to the EGR gas distributor 15 and is distributed to each cylinder of the engine 1 via the intake manifold 5.
  • the bypass valve 17 is warmed and closed.
  • the bypass valve 17 is closed, all of the EGR gas flowing from the exhaust passage 3 to the EGR passage 12 flows to the EGR cooler 13 to be cooled, and further flows to the EGR valve 14 and the EGR gas distributor 15 to drive the intake manifold 5. It is distributed to each cylinder of the engine 1 and circulated.
  • various sensors and the like 70 to 79 provided in this engine system constitute an operating state detecting means for detecting an operating state of the engine 1.
  • the ignition switch (IG switch) 70 provided in the driver's seat is turned on and off by the driver in order to start or stop the engine 1, and outputs an electric signal corresponding to the operation.
  • the water temperature sensor 71 provided in the engine 1 detects the temperature (cooling water temperature) THW of the cooling water flowing inside the engine 1 and outputs an electric signal according to the detected value.
  • the water temperature sensor 71 corresponds to an example of the cooling water temperature detecting means in the disclosed technology.
  • the rotation speed sensor 72 provided in the engine 1 detects the rotation angle (crank angle) of the crankshaft of the engine 1 and uses the change in the crank angle (crank angle speed) as the rotation speed (engine rotation speed) NE of the engine 1. Detects and outputs an electric signal according to the detected value.
  • the air flow meter 73 provided in the vicinity of the air cleaner 9 detects the intake air amount Ga flowing through the air cleaner 9, and outputs an electric signal according to the detected value.
  • the intake pressure sensor 74 provided in the surge tank 5a detects the intake pressure PM in the intake passage 2 (surge tank 5a) downstream of the throttle device 4, and outputs an electric signal according to the detected value.
  • the throttle sensor 75 provided in the throttle device 4 detects the opening degree (throttle opening degree) TA of the throttle valve 4a and outputs an electric signal corresponding to the detected value.
  • the oxygen sensor 76 provided in the exhaust passage 3 between the inlet 12a of the EGR passage 12 and the catalyst 7 detects the oxygen concentration Ox in the exhaust and outputs an electric signal according to the detected value.
  • the intake air temperature sensor 77 provided at the inlet of the air cleaner 9 detects the temperature (intake air temperature) THA of the outside air sucked into the air cleaner 9, and outputs an electric signal according to the detected value.
  • the wall temperature sensor 78 provided in the EGR gas distributor 15 detects the wall temperature (wall temperature) THDW of the EGR gas distributor 15 and outputs an electric signal according to the detected value.
  • the wall temperature sensor 78 corresponds to an example of the EGR temperature detecting means in this disclosed technique.
  • the accelerator sensor 79 provided on the accelerator pedal 10 in the driver's seat detects the amount of depression of the accelerator pedal 10 by the driver as the accelerator opening ACC, and outputs an electric signal according to the detected value.
  • This engine system further includes an electronic control unit (ECU) 80 that controls the system.
  • ECU electronice control unit
  • Various sensors and the like 70 to 79 are connected to the ECU 80, respectively.
  • an injector (not shown) and an ignition coil (not shown) are connected to the ECU 80.
  • the ECU 80 corresponds to an example of the bypass valve failure diagnosis means, the EGR control means, the EGR valve failure diagnosis means, and the engine control means in the disclosed technology.
  • the ECU 80 includes a central processing unit (CPU), various memories, an external input circuit, an external output circuit, and the like.
  • a predetermined control program related to various controls is stored in the memory.
  • the CPU executes fuel injection control, ignition timing control, EGR control, and the like based on a predetermined control program based on the detection signals of various sensors and the like 70 to 79 input via the input circuit.
  • the ECU 80 controls the EGR valve 14 (the step motor thereof) according to the operating state of the engine 1 in the EGR control. Specifically, the ECU 80 controls the EGR valve 14 to be fully closed during engine 1 stop, idle operation, and deceleration operation, and calculates a target EGR opening degree according to the operating state during other operations. However, the EGR valve 14 is controlled to the target EGR opening degree. At this time, when the EGR valve 14 is opened, it is discharged from the engine 1 to the exhaust passage 3, and a part of the exhaust gas is used as EGR gas in the EGR passage 12, the EGR cooler 13, the EGR valve 14, and the EGR gas distributor 15. It flows to the intake passage 2 (intake manifold 5) via the above, and is distributed to each cylinder of the engine 1 to be circulated.
  • bypass valve failure diagnosis control In this embodiment, when the engine 1 is started, the following bypass valve failure diagnosis control is executed in order to diagnose the failure of the bypass valve 17 according to the EGR operating state after the start.
  • FIG. 2 shows the contents of the bypass valve failure diagnosis control of this embodiment by a flowchart.
  • step 110 the ECU 80 determines whether or not the engine 1 has been operated. For example, the ECU 80 can make this determination based on the engine speed NE detected by the rotation speed sensor 72. If the determination result is affirmative, the ECU 80 shifts the process to step 120, and if the determination result is negative, the ECU 80 returns the process to step 100.
  • step 120 the ECU 80 determines whether or not the EGR is on, that is, whether or not the EGR is being executed. If the determination result is affirmative, the ECU 80 shifts the process to step 130, and if the determination result is negative, the ECU 80 returns the process to step 100.
  • the ECU 80 takes in the cooling water temperature THW, the intake air temperature THA, and the wall temperature THDW, respectively, based on the detection values of the water temperature sensor 71, the intake air temperature sensor 77, and the wall temperature sensor 78, and opens the EGR valve 14 ( EGR opening) Take in EEGR.
  • the ECU 80 can obtain, for example, the EGR opening degree EEGR based on the control command value for the step motor of the EGR valve 14.
  • step 140 the ECU 80 determines whether or not the EGR opening degree EEGR is equal to or greater than the predetermined value ⁇ . If the determination result is affirmative, the ECU 80 shifts the process to step 150, and if the determination result is negative, the ECU 80 returns the process to step 100.
  • step 150 the ECU 80 determines whether or not the cooling water temperature THW is smaller than the half-open temperature THVHO of the bypass valve 17.
  • the half-open temperature THVHO means the temperature at which the bypass valve 17 is half-open.
  • FIG. 3 graphically shows the opening characteristic of the bypass valve 17 with respect to the cooling water temperature THW.
  • the temperature (55 ° C.)) THVHO and the temperature at which the bypass valve 17 is fully closed (fully closed temperature (70 ° C.)) THVFC are shown. If the determination result is affirmative, the ECU 80 shifts the process to step 160, and if the determination result is negative, the ECU 80 shifts the process to step 190.
  • step 160 the ECU 80 waits for the elapse of the predetermined time A1 and shifts the process to step 170.
  • step 170 the ECU 80 determines whether or not the wall temperature THDW is lower than the cooling water temperature THW. If the determination result is affirmative, the ECU 80 shifts the process to step 180, and if the determination result is negative, the ECU 80 returns the process to step 100.
  • step 180 in the ECU 80, although the cooling water temperature THW is lower than the half-open temperature THVHO, the wall temperature THDW is lower than the cooling water temperature THW, so that the bypass valve 17 is closed (the bypass valve 17 is closed).
  • the closed failure flag XCL is set to "1", and the process is returned to step 100.
  • step 190 after shifting from step 150, the ECU 80 determines whether or not the cooling water temperature THW is equal to or higher than the fully closed temperature THVFC (see FIG. 3) of the bypass valve 17. If the determination result is affirmative, the ECU 80 shifts the process to step 200, and if the determination result is negative, the ECU 80 returns the process to step 100.
  • step 200 the ECU 80 waits for the elapse of the predetermined time B1 and shifts the process to step 210.
  • step 210 the ECU 80 determines whether or not the wall temperature THDW is equal to or higher than the cooling water temperature THW. If the determination result is affirmative, the ECU 80 shifts the process to step 220, and if the determination result is negative, the ECU 80 shifts the process to step 230.
  • step 220 the ECU 80 fails to open the bypass valve 17 (the bypass valve 17 opens) because the wall temperature THWW is equal to or higher than the cooling water temperature THW even though the cooling water temperature THW is equal to or higher than the fully closed temperature THVFC. It is determined that the failure is caused while the valve is in the valved state), the open failure flag XOP is set to "1", and the process is returned to step 100.
  • step 230 after shifting from step 210, the ECU 80 determines whether or not the closed failure flag XCL is "0". If the determination result is affirmative, the ECU 80 shifts the process to step 240 because the closing failure has not been determined, and if the determination result is negative, the closing failure has been determined. , Return the process to step 100.
  • step 240 since the ECU 80 has not determined whether the bypass valve 17 has opened or closed, it determines that the bypass valve 17 is normal, sets the normal flag XOK to "1", and steps the process. Return to 100.
  • step 250 after shifting from step 100, the ECU 80 sets the open failure flag XOP, the closed failure flag XCL, and the normal flag XOK to "0", respectively.
  • step 260 the ECU 80 stops the engine 1. That is, the control of the fuel supply to the engine 1 and the ignition operation is stopped.
  • step 270 the ECU 80 stops the ECU 80 and then returns the process to step 100.
  • the ECU 80 diagnoses the failure of the bypass valve 17 based on at least the operating state of the bypass valve 17 and the detected wall temperature THDW (the temperature of the wall of the EGR passage 12). It has become. Specifically, after the engine 1 is started, the failure of the bypass valve 17 is diagnosed by comparing the cooling water temperature THW reflecting the operating state of the bypass valve 17 with the wall temperature THW.
  • the correlation between the intake air temperature THA, the wall temperature THDW, and the cooling water temperature THW before the start of the engine 1 is THA ⁇ THDW ⁇ THW after a long stop, and THA ⁇ THDW ⁇ THW after a short stop.
  • the correlation between the intake air temperature THA, the wall temperature THDW and the cooling water temperature THW after the start of the engine 1 is as follows: (1) After a long stop and before the start of the EGR, the cooling water temperature THW is delayed and the wall The temperature THDW rises, the change in the intake air temperature THA is small, and the rise in the wall temperature ⁇ THWW is smaller than the rise in the cooling water temperature THW ⁇ THW.
  • EGR control will be described.
  • the ECU 80 is adapted to execute EGR control as follows according to the diagnosis result of the bypass valve failure diagnosis control described above.
  • FIG. 4 shows the contents of the EGR control by a flowchart.
  • step 300 the ECU 80 determines the cooling water temperature THW, the engine rotation speed NE, and the engine load based on the detection values of the water temperature sensor 71, the rotation speed sensor 72, the intake pressure sensor 74, and the throttle sensor 75. Import each KL.
  • the ECU 80 can obtain, for example, the engine load KL based on the intake pressure PM or the throttle opening degree TA.
  • the ECU 80 calculates the target EGR opening degree TEGR according to the engine speed NE and the engine load KL. For example, the ECU 80 can obtain the target EGR opening degree TEGR according to the engine speed NE and the engine load KL by referring to a predetermined target EGR opening degree map.
  • step 320 the ECU 80 determines whether or not the normal flag XOK is "1", that is, whether or not the failure diagnosis result of the bypass valve 17 is a normal determination. If the determination result is affirmative, the ECU 80 shifts the process to step 330, and if the determination result is negative, the ECU 80 shifts the process to 350.
  • step 330 the ECU 80 determines whether or not the cooling water temperature THW is "40 ° C.” or higher. If the determination result is affirmative, the ECU 80 shifts the process to step 340, and if the determination result is negative, the ECU 80 shifts the process to 410.
  • step 340 the ECU 80 controls the EGR valve 14 to the target EGR opening degree TEGR, and returns the process to step 300.
  • step 410 the ECU 80 sets the target EGR opening TEGR to "0" for EGR cut, and shifts the process to step 340.
  • step 350 after shifting from step 320, it is determined whether or not the closed failure flag XCL is "1", that is, whether or not the failure diagnosis result of the bypass valve 17 is a closed failure determination. If the determination result is affirmative, the ECU 80 shifts the process to step 360 as a closed failure determination, and if the determination result is negative, the ECU 80 shifts the process to 370 as an open failure determination.
  • step 360 the ECU 80 determines whether or not the cooling water temperature THW is "65 ° C.” or higher. If the determination result is affirmative, the ECU 80 shifts the process to step 340, and if the determination result is negative, the ECU 80 shifts the process to 410.
  • step 370 after shifting from step 350, the ECU 80 determines whether or not the cooling water temperature THW is "40 ° C.” or higher. If the determination result is affirmative, the ECU 80 shifts the process to step 380, and if the determination result is negative, the ECU 80 shifts the process to 410.
  • step 380 the ECU 80 determines whether or not the cooling water temperature THW is equal to or higher than the fully closed temperature THVFC. If the determination result is affirmative, the ECU 80 shifts the process to step 390, and if the determination result is negative, the ECU 80 shifts the process to 340.
  • step 390 the ECU 80 determines whether or not the target EGR opening degree TEGR is equal to or greater than the predetermined opening degree C1. If the determination result is affirmative, the ECU 80 shifts the process to step 400, and if the determination result is negative, the ECU 80 shifts the process to 340.
  • step 400 the ECU 80 sets the target EGR opening TEGR to the predetermined opening C1 in order to guard the target EGR opening TEGR at the predetermined opening C1, and shifts the process to step 340.
  • the ECU 80 controls the EGR valve 14 according to the diagnosis result of the failure of the bypass valve 17. Specifically, the ECU 80 controls the EGR valve 14 to an opening degree of C1 (predetermined value) or less when the failure diagnosis result is an open failure of the bypass valve 17 after the EGR start condition is satisfied.
  • the failure diagnosis result is a closed failure of the bypass valve 17
  • the EGR valve 14 is controlled to be fully closed under the valve opening condition of the bypass valve 17.
  • the ECU 80 has the following EGR valve failure in order to diagnose an open failure (for example, due to foreign matter biting) of the EGR valve 14 according to the EGR operating state after the engine 1 is started. It is designed to execute diagnostic control.
  • FIG. 5 shows the contents of the EGR valve failure diagnosis control of this embodiment by a flowchart.
  • This flowchart shows the contents for diagnosing the presence or absence of an open failure of the EGR valve 14 when the EGR valve 14 is controlled to be fully closed or when the EGR valve 14 is controlled to be fully closed during deceleration of the engine 1.
  • step 500 the ECU 80 takes in various signals indicating the operating state of the engine 1 from various sensors and the like 72, 73, 75, 77. That is, the engine rotation speed NE, the engine load KL, the throttle opening TA, the intake amount Ga, and the intake pressure PM, and the motor step number STegr of the step motor corresponding to the opening degree of the EGR valve 14 are taken in, respectively.
  • the ECU 80 can obtain the engine load KL based on the throttle opening TA or the intake pressure PM.
  • the number of motor steps STegr has a relationship proportional to the opening degree (EGR opening degree) of the EGR valve 14.
  • the ECU 80 determines whether or not the operating state of the engine 1 is within the foreign matter biting detection range.
  • the ECU 50 can determine, for example, whether the range defined by the relationship between the engine speed NE and the engine load KL is within a predetermined detection range suitable for detecting foreign matter biting.
  • the predetermined detection range includes deceleration operation or steady operation of the engine 1. If the determination result is affirmative, the ECU 80 shifts the process to step 520, and if the determination result is negative, the ECU 80 returns the process to step 500.
  • step 520 the ECU 80 determines whether or not the number of motor steps STegr is smaller than "8 steps". “8 steps” is an example and corresponds to a minute opening degree of the EGR valve 14. If the determination result is affirmative, the ECU 80 shifts the process to step 530, and if the determination result is negative, the ECU 80 returns the process to step 500.
  • the ECU 80 takes in the fully closed reference intake pressure PMegr0 at the time of deceleration according to the engine speed NE and the engine load KL.
  • the ECU 80 can obtain the fully closed reference intake pressure PMegr0 at the time of deceleration according to the engine speed NE and the engine load KL by referring to a preset fully closed reference intake pressure map (not shown). ..
  • a preset fully closed reference intake pressure map (not shown). ..
  • this fully closed reference intake pressure map the relationship between the fully closed reference intake pressure PMegr0 with respect to the engine speed NE and the engine load KL when the opening (EGR opening) of the EGR valve 14 is "0", that is, when fully closed, is in advance. It is a set map.
  • the intake pressure PM at the time of deceleration of the engine 1 has a correlation with the engine load KL regardless of the presence or absence of foreign matter being caught in the EGR valve 14, and both are substantially proportional to each other.
  • the fully closed reference intake pressure PMegr0 is set for the engine speed NE and the engine load KL in the fully closed reference intake pressure map.
  • step 540 the ECU 80 takes in the pressure increase allowance ⁇ according to the engine speed NE.
  • the ECU 80 can obtain this pressure increase allowance ⁇ , for example, by referring to a predetermined pressure increase allowance map set in advance.
  • This pressure increase allowance ⁇ is added to the fully closed reference intake pressure PMegr0 in order to allow an error or the like at the time of determination described later.
  • step 550 the ECU 80 determines whether or not the detected intake pressure PM is larger than the addition result of the fully closed reference intake pressure PMegr0 and the pressure increase allowance ⁇ . If the determination result is affirmative, the ECU 80 shifts the process to step 560, and if the determination result is negative, the ECU 80 shifts the process to step 580.
  • step 560 the ECU 80 determines that the EGR valve 14 is an open failure due to foreign matter biting, and stores the determination result in the memory.
  • step 570 the ECU 80 calculates the biting foreign matter diameter K ⁇ XOP based on the current intake pressure PM and the fully closed reference intake pressure PMegr0.
  • the ECU 80 can obtain the biting foreign matter diameter K ⁇ XOP according to the difference between the intake pressure PM and the fully closed reference intake pressure PMegr0, for example, by referring to a predetermined biting foreign matter diameter map set in advance. After that, the ECU 80 returns the process to step 500.
  • step 580 after shifting from step 550, the ECU 50 determines that the EGR valve 14 is fully closed and normal, and returns the process to step 500.
  • the ECU 80 diagnoses an open failure of the EGR valve 14 (for example, due to foreign matter biting) based on the detected operating state of the engine 1 (intake pressure PM). It is composed. Specifically, when the engine 1 is decelerating and the ECU 80 controls the EGR valve 14 to be fully closed or the valve is closed, the ECU 80 refers to the fully closed reference intake pressure map to obtain an EGR opening degree. The fully closed reference intake pressure PMegr0 according to the engine rotation speed NE and the engine load KL is obtained.
  • the ECU 80 diagnoses the presence or absence of an open failure (for example, due to foreign matter biting) of the EGR valve 14 by comparing the fully closed reference intake pressure PMegr0 with the detected intake pressure PM. ..
  • the ECU 80 calculates the degree of the open failure (bite foreign matter diameter K ⁇ XOP) based on the detected intake pressure PM and the fully closed reference intake pressure PMegr0 when it is determined that the open failure exists.
  • FIG. 6 shows the contents of the control by a flowchart.
  • the ECU 80 determines in step 600 whether the operating state of the engine 1 is decelerated or idle. The ECU 80 can make this determination based on, for example, the accelerator opening degree ACC and the engine speed NE. If the determination result is affirmative, the ECU 80 shifts the process to step 610, and if the determination result is negative, the ECU 80 returns the process to step 600.
  • step 610 the ECU 80 determines whether or not the EGR valve 14 has an open failure.
  • the ECU 80 can make this determination based on the diagnosis result by the EGR valve failure diagnosis control. If the determination result is affirmative, the ECU 80 shifts the process to step 620, and if the determination result is negative, the ECU 80 returns the process to step 600.
  • step 620 the ECU 80 determines whether the bypass valve 17 is open or not. The ECU 80 can make this determination based on the diagnosis result by the bypass valve failure diagnosis control. If the determination result is affirmative, the ECU 80 shifts the process to step 630, and if the determination result is negative, the ECU 80 shifts the process to step 640.
  • step 630 the ECU 80 causes a double failure in which both the EGR valve 14 and the bypass valve 17 are open failures. Therefore, after prohibiting the engine stall countermeasure control, the process is returned to step 600.
  • the open failure of the EGR valve 14 and the open failure of the bypass valve 17 double failure
  • high-temperature EGR gas flows into the resin EGR gas distributor 15 and the intake manifold 5, and these There is a risk of melting damage.
  • engine stall countermeasure control for example, idle-up control
  • the implementation of engine stall countermeasure control that is effective when the EGR valve 14 is opened is prohibited. That is, it is designed to be stalled. In this way, the engine stall control is prohibited and the vehicle is intentionally stalled to make the vehicle unable to drive normally and to urge the driver to repair it.
  • step 640 since the open failure of the EGR valve 14 and the open failure of the bypass valve 17 do not overlap, the ECU 80 executes the engine stall countermeasure control (for example, idle-up control) and returns the process to step 600. That is, since only the EGR valve 14 has an open failure, the ECU 80 executes the engine stall countermeasure control.
  • the engine stall countermeasure control for example, idle-up control
  • the ECU 80 determines that the diagnosis result by the bypass valve failure diagnosis control is the open failure of the bypass valve 17 and the diagnosis result by the EGR valve failure diagnosis control is the open failure of the EGR valve 14. It is designed to prohibit the control of anti-stall measures.
  • This prohibition of anti-stall control means that when the operating state of the engine 1 is decelerated or idle, the engine stalls without helping to stall, and the throttle is used to limit the output of the engine 1. It corresponds to controlling the device 4 (output adjusting means).
  • the EGR gas lowered to an appropriate temperature flows to the intake passage 2 (including the intake manifold 5) through the downstream EGR passage 12 (including the EGR gas distributor 15).
  • the bypass valve 17 is normally closed, almost all of the EGR gas flowing from the exhaust passage 3 to the EGR passage 12 flows to the EGR cooler 13, and heat is exchanged by the EGR cooler 13 to lower the temperature to an appropriate level.
  • EGR gas at a different temperature flows to the intake passage 2 (including the intake manifold 5) via the downstream EGR passage 12 (including the EGR gas distributor 15).
  • the ECU 80 fails the bypass valve 17 based on at least the operating state (open / closed state) of the bypass valve 17 and the wall temperature THDW of the EGR passage 12 (including the EGR gas distributor 15) detected by the wall temperature sensor 78. To diagnose. Then, the ECU 80 controls the EGR valve 14 according to the diagnosis result of the failure of the bypass valve 17. Therefore, since the EGR valve 14 is controlled according to the diagnosis result of the failure of the bypass valve 17, the high temperature EGR gas is prevented from unnecessarily flowing to the downstream EGR passage 12 (including the EGR gas distributor 15). It becomes possible.
  • the ECU 80 when the diagnosis result by the ECU 80 is an open failure of the bypass valve 17 after the EGR start condition is satisfied, the ECU 80 opens the EGR valve 14 at a predetermined opening degree C1 (predetermined value) or less. Since the opening degree is controlled, the flow rate of the high temperature EGR gas flowing to the downstream EGR passage 12 (including the EGR gas distributor 15) is suppressed, and the temperature of the EGR gas flowing to the downstream EGR passage 12 is reduced.
  • the diagnosis result of the bypass valve 17 by the ECU 80 when the diagnosis result of the bypass valve 17 by the ECU 80 is a closed failure, the ECU 80 controls the EGR valve 14 to be fully closed under the valve opening condition of the bypass valve 17, so that the downstream EGR passage 12 (EGR gas distribution) is used.
  • the ECU 80 compares the cooling water temperature THW detected by the water temperature sensor 71 after the engine 1 is started with the wall temperature THW of the EGR gas distributor 15 detected by the wall temperature sensor 78. By doing so, the failure of the bypass valve 17 is diagnosed.
  • the water temperature sensor 71 is usually used to control the engine 1. Therefore, in order to diagnose the failure of the bypass valve 17, it is not necessary to provide a special detecting means other than the wall temperature sensor 78. Therefore, the configuration of the EGR system can be simplified and the product cost can be suppressed because it is not necessary to provide a special detection means.
  • the ECU 80 controls the engine stall. Is prohibited. Therefore, in the case of an open failure in which the EGR valve 14 cannot be controlled (double failure) in addition to the open failure of the bypass valve 17, the output of the engine 1 is limited by the throttle device 4, so that the engine 1 is normally operated. You will not be able to make it. Therefore, it is possible to promptly notify the driver that the engine 1 cannot be operated normally, and urge the driver to repair the bypass valve 17 and the EGR valve 14 as soon as possible for a double failure.
  • the ECU 80 determines the engine stall countermeasure control (for example, idle-up control) which is effective when the EGR valve 14 opens failure.
  • the implementation is intentionally prohibited. Therefore, after the engine 1 is started, an engine stall can be generated at the time of deceleration or idle, and the driver can be urged to repair.
  • bypass valve 17 since the bypass valve 17 operates in response to a change in the temperature of the cooling water, it is not necessary to electrically control the bypass valve 17, and the configuration relating to the bypass valve 17 is simplified. Therefore, the product cost as an EGR system can be suppressed.
  • This embodiment is different from the first embodiment in the content of the bypass valve failure diagnosis control executed by the ECU 80.
  • FIG. 7 shows the contents of the bypass valve failure diagnosis control of this embodiment by a flowchart.
  • the flowchart shown in FIG. 7 is different from the first embodiment in that step 700 and step 710 are provided instead of step 210 in the flowchart of FIG.
  • the ECU 80 calculates the correction temperature KTHW according to the EGR opening degree EEGR in step 700.
  • the ECU 80 can obtain the correction temperature KTHW according to the EGR opening degree EEGR by referring to the correction temperature map as shown in FIG. 8, for example.
  • the correction temperature KTHW is set so that the EGR opening EEGR becomes "0" from the fully closed state to the predetermined opening E1 and increases linearly from the predetermined opening E1 to the fully open. Will be done.
  • step 710 the ECU 80 determines whether or not the wall temperature THDW is equal to or higher than the addition result of the cooling water temperature THW and the correction temperature KTHW. If the determination result is affirmative, the ECU 80 shifts the process to step 220, and if the determination result is negative, the ECU 80 shifts the process to 230.
  • the ECU 80 corrects the detected cooling water temperature THW according to the opening degree of the EGR valve 14, unlike the first embodiment.
  • the cooling water temperature THW is corrected according to the EGR opening EEGR because the temperature of the EGR gas flowing out from the EGR cooler 13 and the bypass passage 16 increases as the flow rate of the EGR gas increases, that is, the EGR valve 14. This is because it becomes higher as the opening degree of is increased.
  • the ECU 80 corrects the detected cooling water temperature THW according to the opening degree of the EGR valve 14.
  • the temperature of the EGR gas flowing through the EGR passage 12 changes according to the flow rate of the EGR gas, that is, the opening degree of the EGR valve 14. Therefore, the cooling water temperature THW to be compared with the wall temperature THDW of the EGR passage 12 (including the EGR gas distributor 15) is corrected according to the flow rate of the EGR gas. Therefore, the failure of the bypass valve 17 can be accurately diagnosed.
  • This embodiment differs from each of the above embodiments in the content of the fail-safe control of the engine.
  • FIG. 9 shows the contents of the fail-safe control of the engine in this embodiment by a flowchart.
  • the ECU 80 calculates the target throttle opening TTA based on the detected accelerator opening ACC in step 800.
  • the ECU 80 can obtain the target throttle opening TTA according to the accelerator opening ACC by referring to the target throttle opening map shown in FIG. 10, for example.
  • step 810 the ECU 80 determines whether or not the bypass valve 17 is open.
  • the ECU 80 can make this determination based on the diagnosis result by the bypass valve failure diagnosis control. If the determination result is affirmative, the ECU 80 shifts the process to step 820, and if the determination result is negative, the ECU 80 shifts the process to step 860.
  • step 820 the ECU 80 determines whether or not the EGR valve 14 has an open failure.
  • the ECU 80 can make this determination based on the diagnosis result by the EGR valve failure diagnosis control. If the determination result is affirmative, the ECU 80 shifts the process to step 830, and if the determination result is negative, the ECU 80 shifts the process to step 860.
  • step 830 the ECU 80 takes in the open failure opening TEGROD of the EGR valve 14.
  • the ECU 80 can obtain this open failure opening TEGROD based on the biting foreign matter diameter K ⁇ XOP obtained by the EGR valve failure diagnosis control, for example, by referring to a predetermined map.
  • step 840 the ECU 80 calculates the limited throttle opening TAEM according to the open failure opening TEGROD.
  • the ECU 80 can obtain the limited throttle opening TAEM according to the open failure opening TEGROD by referring to the limited throttle opening map shown in FIG. 11, for example. In this map, the limit throttle opening TAEM is set to decrease as the open failure opening TEGROD increases.
  • step 850 the ECU 80 determines whether or not the target throttle opening TTA is less than the limit throttle opening TAEM. If the determination result is affirmative, the ECU 80 shifts the process to step 860, and if the determination result is negative, the ECU 80 shifts the process to step 870.
  • step 860 the ECU 80 sets the target throttle opening TTA as the final control throttle opening LTTA. Then, the ECU 80 controls the throttle device 4 to this final control throttle opening degree LTTA. After that, the ECU 80 returns the process to step 800.
  • step 870 the ECU 80 sets the limited throttle opening TAEM as the target throttle opening TTA, and then shifts the process to step 860.
  • the ECU 80 outputs the output of the engine 1 unlike the above embodiments.
  • the throttle device 4 output adjusting means
  • the throttle device 4 is controlled to a limited throttle opening TAEM smaller than the original target throttle opening TTA.
  • This embodiment is different from the third embodiment in the content of the fail-safe control of the engine.
  • FIG. 12 shows the contents of the fail-safe control of the engine in this embodiment by a flowchart.
  • the flowchart shown in FIG. 12 differs from the third embodiment in that steps 900, 910, and 920 are provided in place of steps 840, 850, and 870 of the flowchart of FIG.
  • the ECU 80 calculates the fuel cut throttle opening TAEMFC according to the open failure opening TEGROD in step 900 after executing the processes of steps 800 to 830.
  • the ECU 80 can obtain the fuel cut throttle opening TAEMFC according to the open failure opening TEGROD by referring to the fuel cut throttle opening map according to FIG. 11, for example.
  • step 910 the ECU 80 determines whether or not the target throttle opening TTA is less than the fuel cut throttle opening TAEMFC. If the determination result is affirmative, the ECU 80 shifts the process to step 860, and if the determination result is negative, the ECU 80 shifts the process to step 920.
  • step 920 the ECU 80 is configured to execute a fuel cut (cut off the supply of fuel to the engine 1). Therefore, the ECU 80 controls the fuel injection device. After that, the ECU 80 shifts the process to step 860.
  • the ECU 80 is a fuel injection device (output) in order to limit the output of the engine 1 when a double failure of the bypass valve 17 and the EGR valve 14 occurs, unlike the third embodiment.
  • the adjusting means is controlled to cut the fuel.
  • the bypass valve 17 is configured to open or close according to the temperature of the cooling water, but the bypass valve is opened or closed according to the temperature of the EG gas. It can also be configured.
  • thermowax is used for the bypass valve 17 as an actuator that operates in response to a change in temperature, but bimetal or a shape memory alloy can also be used instead of the thermowax.
  • a wall temperature sensor 78 for detecting the temperature of the inner wall of the EGR gas distributor 15 is provided as an EGR temperature detecting means for detecting the temperature of the EGR passage 12 downstream of the EGR cooler 13.
  • a wall temperature sensor that detects the temperature of the inner wall of the EGR passage 12 itself can be provided.
  • a wall temperature sensor 78 for detecting the temperature of the inner wall of the EGR gas distributor 15 is provided as an EGR temperature detecting means for detecting the temperature of the EGR passage 12 downstream of the EGR cooler 13.
  • an EGR gas temperature sensor for detecting the temperature of the EGR gas can also be provided as an EGR temperature detecting means.
  • This disclosure technology can be applied to gasoline engines and diesel engines mounted on vehicles.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Analytical Chemistry (AREA)
  • Exhaust-Gas Circulating Devices (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)

Abstract

Ce système d'EGR comprend : une vanne EGR (14) qui régule le débit de gaz EGR dans un passage d'EGR (12) ; un refroidisseur EGR (13) qui effectue un échange de chaleur entre le gaz EGR et l'eau de refroidissement du moteur pour refroidir le gaz EGR s'écoulant à travers le passage d'EGR (12) ; un passage de dérivation (16) qui permet à une partie du gaz EGR s'écoulant vers le refroidisseur EGR (13) dans le passage d'EGR (12) d'éviter le refroidisseur EGR (13) ; une soupape de dérivation (17) qui ouvre et ferme le passage de dérivation (16) ; un capteur de température de paroi (78) qui est disposé dans le passage d'EGR (12) en aval du refroidisseur EGR (13) et du passage de dérivation (16), et qui détecte la température de paroi du passage d'EGR (12) ; et une unité de commande électronique (80) qui diagnostique une défaillance de la vanne de dérivation (17) sur la base d'au moins l'état de fonctionnement de la soupape de dérivation (17) et de la température de paroi détectée, et qui commande la vanne EGR (14) en fonction du résultat du diagnostic.
PCT/JP2021/021502 2020-07-31 2021-06-07 Système d'egr WO2022024551A1 (fr)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003247459A (ja) * 2002-02-20 2003-09-05 Toyota Motor Corp 内燃機関のｅｇｒ機構
JP2010539388A (ja) * 2007-09-20 2010-12-16 ルノー・エス・アー・エス 排気ガス再循環回路の熱交換器バイパスフラップの診断方法

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003247459A (ja) * 2002-02-20 2003-09-05 Toyota Motor Corp 内燃機関のｅｇｒ機構
JP2010539388A (ja) * 2007-09-20 2010-12-16 ルノー・エス・アー・エス 排気ガス再循環回路の熱交換器バイパスフラップの診断方法

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