JP4379407B2 - Diagnostic device for exhaust gas recirculation system - Google Patents

Description

  The present invention relates to a diagnostic device for an exhaust gas recirculation device.

  Conventionally, an exhaust gas recirculation (EGR) device that recirculates part of exhaust gas discharged from an internal combustion engine to an intake system is known. In general, the diagnosis of such an exhaust gas recirculation device is performed in such a manner as not to deteriorate drivability and emission.

  For example, Patent Document 1 describes a technique for detecting the presence or absence of a failure by continuing operation of an internal combustion engine after key-off and operating an EGR valve. Patent Document 2 describes a method of diagnosing a failure of an EGR valve in a hybrid vehicle (HV vehicle) using a deceleration cylinder suspension operation.

JP-A-2-78765 JP 2003-184595 A

  However, in the technique described in Patent Document 1 described above, fuel consumption for diagnosis is required and components may be discharged in advance. Moreover, in the technique described in Patent Document 2, since the decelerating cylinder suspension operation is used, there is a case where a highly accurate diagnosis cannot be performed due to fluctuations in the rotational speed of the internal combustion engine.

  The present invention has been made to solve such problems, and the object of the present invention is to perform highly accurate diagnosis on an exhaust gas recirculation device mounted on a hybrid vehicle. Another object of the present invention is to provide a diagnostic apparatus for an exhaust gas recirculation device.

In one aspect of the present invention, diagnostic apparatus for an internal combustion engine and an exhaust gas recirculation system for performing diagnostics on onboard exhaust gas recirculation system in a hybrid vehicle having a motor generator as a power source, the internal combustion engine is stopped when it is, and a control means for operating the internal combustion engine by driving the motor generator, when the internal combustion engine is operated by the control means, the opening of the EGR valve with said exhaust gas recirculation system Diagnostic means for making a diagnosis on the degree .

The diagnostic apparatus for exhaust gas recirculation apparatus described above is applied to a hybrid vehicle having an internal combustion engine and a motor generator as power sources. A diagnostic device for an exhaust gas recirculation device includes a control means for operating an internal combustion engine by driving a motor generator when the internal combustion engine is stopped , and an exhaust gas when the internal combustion engine is operated by the control means. Diagnostic means for diagnosing the opening degree of the EGR valve included in the recirculation device. According to the exhaust gas recirculation device diagnosis apparatus described above, since the internal combustion engine can be maintained in a desired state by actively operating the internal combustion engine by the motor generator, the accuracy of the diagnosis can be improved. Can be improved. Note that when the internal combustion engine is operated by the control means, the fuel supply to the internal combustion engine is stopped.

  In one aspect of the diagnostic apparatus for the exhaust gas recirculation device, the control means drives the motor generator so that the rotational speed of the internal combustion engine becomes a predetermined rotational speed. As a result, the diagnosis can be performed with the rotation speed of the internal combustion engine kept constant, and the accuracy of the diagnosis can be further improved.

Preferably, the internal combustion engine is stopped when traveling using only the motor generator as a power source and when the vehicle is stopped.

  In another aspect of the exhaust gas recirculation device diagnostic apparatus, the diagnostic means includes an intake air amount when the opening degree of the EGR valve is changed while the throttle valve is set to a predetermined opening degree, and Based on a change in at least one of the intake pipe pressures, the relationship between the opening degree commanded to the EGR valve and the actual opening degree of the EGR valve is diagnosed.

  In this embodiment, the exhaust gas recirculation device diagnosis device diagnoses the EGR valve by changing the opening of the EGR valve in a state where the throttle valve is set to a predetermined opening. Based on the change in intake air amount or intake pipe pressure obtained when the opening degree of the EGR valve is controlled in this way, the opening degree (command opening degree) commanded to the EGR valve and the EGR valve actually opened. The opening (actual opening) is known. Therefore, according to the diagnostic apparatus for the exhaust gas recirculation device described above, the relationship between the command opening degree of the EGR valve and the actual opening degree can be appropriately diagnosed.

  In another aspect of the exhaust gas recirculation device diagnosis apparatus, the diagnosis unit performs determination in a state where the opening degree of the throttle valve is set to a predetermined opening degree, and, depending on a result of the determination, The throttle valve opening is changed from the predetermined opening to the fully closed state, and when the fully closed command is issued to the EGR valve, it is diagnosed whether or not the EGR valve is set to the fully closed state. .

  In this aspect, the exhaust gas recirculation system diagnosis device actually sets the EGR valve at the time of full-close command based on the intake air amount or intake pipe pressure obtained when the throttle valve opening is set to be fully closed. Diagnose whether it is set to fully closed. Specifically, the determination is made with the throttle valve opening set to a predetermined opening, and the above diagnosis is made according to the result of this determination. That is, only when it is determined that the EGR valve may not be fully closed, the above diagnosis is performed with the throttle opening fully closed. As a result, the diagnosis can be performed while appropriately suppressing the deterioration of the fuel consumption that can occur by fully closing the throttle opening.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

[Vehicle configuration]
FIG. 1 is a schematic diagram showing an overall configuration of a vehicle 100 to which a diagnostic apparatus for an exhaust gas recirculation device according to the present embodiment is applied. In FIG. 1, solid arrows indicate gas flows, broken arrows indicate input / output of signals, and alternate long and short dash arrows indicate transmission destinations of driving force.

  The vehicle 100 mainly includes an intake passage 3, an air flow meter 4, a throttle valve 5, an engine (internal combustion engine) 6, an exhaust passage 7, an EGR passage 8, an EGR valve 9, an ECU (Engine Control Unit). ) 10, motor generator 21, power split mechanism 22, transmission mechanism 23, and wheels 25. The vehicle 100 is configured as a hybrid vehicle having an engine 6 and a motor generator 21 as power sources.

  Air sucked from the outside passes through the intake passage 3. In the intake passage 3, an air flow meter 4 that detects the flow rate (intake air amount) of intake air passing through the intake passage 3 and a throttle valve 5 that adjusts the intake air amount are provided. A detection signal S1 corresponding to the intake air amount detected by the air flow meter 4 is supplied to the ECU 10. The throttle valve 5 has its opening degree (hereinafter, also simply referred to as “throttle opening degree”) controlled by a control signal S <b> 2 supplied from the ECU 10.

  The engine 6 is a device that generates power by causing an air-fuel mixture obtained by mixing fuel and air supplied from the intake passage 3 to explode in a combustion chamber. The power generated by the engine 6 is transmitted to a power split mechanism 22 described later. Moreover, as the engine 6, a gasoline engine etc. can be used, for example.

  Exhaust gas discharged from the engine 6 flows through the exhaust passage 7. An EGR passage 8 is connected in the exhaust passage 7. Specifically, the EGR passage 8 has one end connected to the exhaust passage 7 and the other end connected to the intake passage 3. A part of the exhaust gas flows into the EGR passage 8 and the exhaust gas thus flowed back to the intake system. Further, an EGR valve 9 is provided on the EGR passage 8, and the flow rate of exhaust gas recirculated to the intake system is adjusted by the EGR valve 9. Specifically, the opening degree of the EGR valve 9 is controlled by a control signal S3 supplied from the ECU 10. Thus, the EGR passage 8 and the EGR valve 9 operate as the exhaust gas recirculation device 50.

  On the other hand, the motor generator 21 functions as an electric motor that assists the driving force of the engine 6 and also functions as a generator that charges a battery (not shown). The motor generator 21 is controlled by a control signal S4 supplied from the ECU 10.

  The power split mechanism 22 is a planetary gear mechanism including a sun gear, a planetary carrier, a pinion gear, and a ring gear (not shown). The rotation shaft of the sun gear is connected to the motor generator 21, and the rotation shaft of the planetary carrier is connected to the engine 6. The rotating shaft of the ring gear is connected to the transmission mechanism 23, and the driving force is transmitted to the wheels 25 via the transmission mechanism 23.

  In the vehicle 100 configured as a hybrid vehicle in this manner, the operations of the engine 6 and the motor generator 21 are performed in the running state of the vehicle 100 such as starting, starting, normal traveling, light load traveling, braking, and the like. It is controlled according to the storage state of the battery. For example, the distribution of driving force between the engine 6 and the motor generator 21 and whether the motor generator 21 is operated as an electric motor or a generator are controlled.

  The ECU 10 includes a CPU, a ROM, a RAM, an A / D converter, an input / output interface, and the like (not shown). As described above, the ECU 10 controls the opening degree of the throttle valve 5 and the EGR valve 9 and the motor generator 21 based on outputs of various sensors (for example, the air flow meter 4) in the vehicle 100. Specifically, in this embodiment, the ECU 10 controls the engine 6 to operate by driving the motor generator 21 when the output to the drive shaft of the engine 6 is cut off, and the engine 6 operates by the control means. In this case, it functions as a diagnostic means for performing a diagnosis on the exhaust gas recirculation device 50. That is, the ECU 10 functions as a diagnostic device for the exhaust gas recirculation device. Further, the ECU 10 performs various controls based on the diagnosis result for the exhaust gas recirculation device 50.

[Diagnostic method for exhaust gas recirculation system]
Next, the diagnostic method of the exhaust gas recirculation device 50 will be described in detail.

  In the present embodiment, when the output to the drive shaft of the engine 6 is interrupted, the engine 6 is operated by driving the motor generator 21 (the operation of the engine 6 by the motor generator 21 in this way is described below. Will be referred to as “motoring”), and the exhaust gas recirculation device 50 is diagnosed during motoring in this way. Specifically, when the output to the drive shaft of the engine 6 is cut off, the vehicle 100 travels using only the motor generator 21 as a power source (hereinafter referred to as “EV travel”), and the vehicle 100 It means at least one of when stopped. In the present embodiment, the diagnosis for the EGR valve 9 is performed as a diagnosis for the exhaust gas recirculation device 50. In addition, when the engine 6 is motored for diagnosis, the fuel supply to the engine 6 is stopped.

  As described above, in the present embodiment, the motor generator 21 performs motoring when the vehicle 100 is running on EV or is stopped, and the EGR valve 9 is diagnosed during motoring. Thereby, deterioration of the emission etc. resulting from diagnosis execution can be suppressed. Further, by actively operating the engine 6 by the motor generator 21, the rotation speed of the engine 6 (engine rotation speed) can be kept constant. Therefore, according to the diagnosis method of the exhaust gas recirculation device 50 according to the present embodiment, the diagnosis of the EGR valve 9 can be performed in a state where the rotation speed of the engine 6 is kept constant, so that the accuracy of diagnosis is improved. It becomes possible.

  Below, the Example of the diagnostic method of the exhaust-gas recirculation apparatus 50 is described.

(First embodiment)
First, a diagnostic method for the exhaust gas recirculation device 50 according to the first embodiment will be described. In the first embodiment, the EGR valve 9 is diagnosed based on a change in the intake air amount when the opening of the throttle valve 5 and the opening of the EGR valve 9 are controlled. More specifically, the EGR valve 9 is diagnosed based on a change in the intake air amount when the opening degree of the EGR valve 9 is changed in a state where the opening degree of the throttle valve 5 is set to the opening degree Ks1. The change in the intake air amount obtained when the opening degree of the EGR valve 9 is controlled in this way corresponds to the change in the flow rate of the gas passing through the EGR passage 8. Therefore, the opening degree commanded to the EGR valve 9 (the opening degree corresponding to the control signal S3, hereinafter referred to as “command opening degree”) and the flow rate of the gas actually passing through the EGR passage 8 I understand the relationship. Thus, since the opening degree of the EGR valve 9 actually opened (hereinafter referred to as “actual opening degree”) is known from the flow rate of the gas that has passed through the EGR passage 8, the command opening degree and the actual opening degree of the EGR valve 9 are known. A relationship with the degree can be obtained.

  Thus, in the first embodiment, as a diagnosis for the exhaust gas recirculation device 50, a diagnosis is made on the relationship between the command opening degree of the EGR valve 9 and the actual opening degree. Furthermore, in the first embodiment, the obtained diagnosis result is reflected in the control for the EGR valve 9.

  FIG. 2 is a flowchart showing a diagnostic process of the exhaust gas recirculation device 50 according to the first embodiment. This process is repeatedly executed by the ECU 10 at a predetermined cycle.

  First, in step S101, the ECU 10 determines whether or not the vehicle 100 is traveling on an EV. Specifically, the ECU 10 makes a determination based on the operating state of the motor generator 21 and the engine 6. If the vehicle is traveling in EV (step S101; Yes), the process proceeds to step S102. In this case, in order to diagnose the EGR valve 9, processing described later is executed. On the other hand, when the vehicle is not traveling in EV (step S101; No), the process exits the flow. In this case, the diagnosis for the EGR valve 9 is not performed.

  In step S102, the ECU 10 performs motoring by controlling the motor generator 21 so that the engine speed becomes a predetermined speed. Then, the process proceeds to step S103.

  In step S103, first, the ECU 10 sets the throttle opening to the opening Ks1, and fully closes the EGR valve 9. Then, the ECU 10 acquires the intake air amount GA1 from the air flow meter 4, and stores the acquired intake air amount GA1. In this case, almost no gas flows through the EGR passage 8. Therefore, the intake air amount GA1 corresponds to the flow rate of the gas flowing through the intake passage 3 when almost no gas flows through the EGR passage 8. When the above process ends, the process proceeds to step S104.

  In step S104, the ECU 10 sets the EGR valve 9 from the fully closed position to the opening degree Ke2 while maintaining the throttle opening degree at the opening degree Ks1. This opening degree Ke2 corresponds to the command opening degree commanded to the EGR valve 9. Then, the ECU 10 acquires the intake air amount GA2 from the air flow meter 4, and stores the acquired intake air amount GA2. In this case, gas flows through the EGR passage 8. Therefore, the intake air amount GA2 corresponds to the flow rate of the gas flowing through the intake passage 3 when the EGR valve 9 is set to the opening degree Ke2. When the above process ends, the process proceeds to step S105.

  In step S105, the ECU 10 calculates the actual opening of the EGR valve 9 based on the difference between the intake air amount GA1 obtained in step S103 and the intake air amount GA2 obtained in step S104. The difference between the intake air amount GA1 and the intake air amount GA2 corresponds to the flow rate of the gas passing through the EGR passage 8 when the EGR valve 9 is set to the opening degree Ke2. Therefore, the actual opening degree of the EGR valve 9 can be obtained from the difference between the intake air amount GA1 and the intake air amount GA2. Specifically, the ECU 10 obtains the actual opening degree from the difference between the intake air amount GA1 and the intake air amount GA2, using a map obtained in advance.

  Then, the ECU 10 learns the relationship between the command opening (corresponding to the opening Ke2) and the obtained actual opening and reflects it in the next control to the EGR valve 9. For example, when the actual opening is larger than the command opening, the command opening commanded to the EGR valve 9 is reduced, and when the actual opening is smaller than the command opening, the EGR valve 9 is Increase the command opening. When the above process ends, the process exits the flow.

  Thus, according to the diagnostic processing of the exhaust gas recirculation device 50 according to the first embodiment, the diagnostic accuracy for the EGR valve 9 can be improved. Moreover, the control with respect to the EGR valve 9 can be accurately performed using the diagnosis result.

  In the above description, the EGR valve 9 is set to one opening degree (in other words, the opening degree GA2 is set from the fully closed state) to perform the diagnosis. However, the EGR valve 9 is set to a plurality of opening degrees. Diagnosis may be performed.

  FIG. 3 shows a diagnostic process of the exhaust gas recirculation device 50 performed by setting the EGR valve 9 to two opening degrees. This process is also repeatedly executed by the ECU 10 at a predetermined cycle. In addition, since the process of step S201-S204 is the same as that of step S101-S104 mentioned above, these description is abbreviate | omitted. Here, the processing after step S205 will be described.

  In step S205, the ECU 10 sets the EGR valve 9 from the opening Ke2 to the opening Ke3 while maintaining the throttle opening at the opening Ks1. The opening degree Ke3 corresponds to a command opening degree that is commanded to the EGR valve 9. Then, the ECU 10 acquires the intake air amount GA3 from the air flow meter 4, and stores the acquired intake air amount GA3. The intake air amount GA3 corresponds to the flow rate of the gas flowing through the intake passage 3 when the EGR valve 9 is set to the opening degree Ke3. When the above process ends, the process proceeds to step S206.

  In step S206, the ECU 10 calculates the actual opening of the EGR valve 9 based on the intake air amounts GA1, GA2, and GA3 obtained in the processes of steps S203, S204, and S205. In this case, the difference between the intake air amount GA1 and the intake air amount GA2 corresponds to the flow rate of the gas passing through the EGR passage 8 when the EGR valve 9 is set to the opening degree Ke2, and the intake air amount GA1 and the intake air amount. The difference from GA3 corresponds to the flow rate of gas passing through the EGR passage 8 when the EGR valve 9 is set to the opening degree Ke3. The ECU 10 obtains the actual opening based on a map obtained in advance using both the difference between the intake air amount GA1 and the intake air amount GA2 and the difference between the intake air amount GA1 and the intake air amount GA3. . Then, the ECU 10 learns the relationship between the command opening for the EGR valve 9 (corresponding to the openings Ke2 and Ke3) and the obtained actual opening and reflects it in the next control to the EGR valve 9. When the above process ends, the process exits the flow.

  In this way, the diagnosis accuracy of the exhaust gas recirculation device 50 can be further improved by setting the EGR valve 9 to two opening degrees.

  In the above-described diagnosis processing of the exhaust gas recirculation device 50, an example is shown in which the EGR valve 9 is diagnosed while the vehicle 100 is traveling in EV (see steps S101 and S201). In addition, diagnosis for the EGR valve 9 can be performed.

(Second embodiment)
Next, a diagnostic method for the exhaust gas recirculation device 50 according to the second embodiment will be described. In the first embodiment, the relationship between the command opening of the EGR valve 9 and the actual opening is diagnosed. However, in the second embodiment, when a command for fully closing the EGR valve 9 is issued (fully closed). Diagnose whether or not the EGR valve 9 is actually fully closed (at the time of command). That is, in the first embodiment, the diagnosis is performed based on the idea that the EGR valve 9 is set to be fully closed at the time of the fully closed command (in other words, almost no gas flows through the EGR passage 8 at the time of the fully closed command). However, in the second embodiment, a diagnosis is made as to whether or not the EGR valve 9 is actually fully closed at the time of the fully closed command.

  Specifically, it is considered that deposits or the like on the EGR valve 9 are not mainly closed as described above. Therefore, in the second embodiment, whether or not deposits or the like are attached to the EGR valve 9. Make a diagnosis. Specifically, based on the difference between the intake air amount GA6 obtained when the throttle opening is substantially fully closed and a full close command is issued to the EGR valve 9, and a predetermined set value α6, the EGR valve 9 is diagnosed as to whether or not deposits are attached. More specifically, when it is determined that the intake air amount GA5 obtained is relatively larger than the set value α5 when the throttle opening is set to the opening Ks5 and the fully closed command is issued to the EGR valve 9. In addition, the above-described diagnosis is performed by setting the throttle opening to the fully closed position from the opening Ks5. That is, after making the determination by setting the throttle opening to the opening Ks5, the diagnosis is performed with the throttle opening fully closed.

  The reason for diagnosing in this order is as follows. If the throttle opening is fully closed, pump loss may increase and fuel consumption may deteriorate. Therefore, without making a diagnosis with the throttle opening fully closed from the beginning, first, there is a possibility that deposits may adhere to the EGR valve 9 with the throttle opening set to the opening Ks5. After the above determination is made, the above diagnosis is performed with the throttle opening fully closed only for the EGR valve 9 where deposits may be attached. Thereby, the diagnosis can be performed while appropriately suppressing deterioration of fuel consumption due to an increase in pump loss.

  FIG. 4 is a flowchart showing a diagnostic process of the exhaust gas recirculation device 50 according to the second embodiment. This process is repeatedly executed by the ECU 10 at a predetermined cycle.

  First, in step S301, the ECU 10 determines whether or not the vehicle 100 is traveling on an EV. If the vehicle is traveling in EV (step S301; Yes), the process proceeds to step S302. On the other hand, when the vehicle is not in EV travel (step S301; No), the process exits the flow. In step S302, the ECU 10 performs motoring by controlling the motor generator 21 so that the engine speed becomes a predetermined speed, and the process proceeds to step S303.

  In step S303, first, the ECU 10 sets the throttle opening to the opening Ks5 and issues a full-close command to the EGR valve 9. Next, the ECU 10 acquires the intake air amount GA5 from the air flow meter 4, and stores the acquired intake air amount GA5. Then, the process proceeds to step S304.

  In step S304, the ECU 10 determines whether or not the difference between the intake air amount GA5 obtained in step S303 and the set value α5 is larger than the determination value β5. That is, in step S304, it is determined whether or not there is a possibility that deposits are attached to the EGR valve 9. The set value α5 and the determination value β5 are obtained from a preset map or the like.

  If the difference between the intake air amount GA5 and the set value α5 is larger than the determination value β5 (step S304; Yes), the process proceeds to step S305. In this case, there is a possibility that deposits are attached to the EGR valve 9. On the other hand, when the difference between the intake air amount GA5 and the set value α5 is equal to or smaller than the determination value β5 (step S304; No), the process exits the flow. In this case, there is no possibility that deposits are attached to the EGR valve 9.

  In step S305, the ECU 10 changes the throttle opening from the opening Ks5 to the fully closed state (including the fully closed state and the vicinity of the fully closed state) while maintaining the fully closed command for the EGR valve 9. Next, the ECU 10 acquires the intake air amount GA6 from the air flow meter 4, and stores the acquired intake air amount GA6. Then, the process proceeds to step S306.

  In step S306, the ECU 10 determines whether or not the difference between the intake air amount GA6 obtained in step S305 and the set value α6 is larger than the determination value β6. That is, in step S306, it is determined whether or not deposits are attached to the EGR valve 9. The set value α6 and the determination value β6 are obtained from a preset map or the like.

  If the difference between the intake air amount GA6 and the set value α6 is larger than the determination value β6 (step S306; Yes), the process proceeds to step S307. In step S307, the ECU 10 diagnoses that deposits are attached to the EGR valve 9. Then, the process exits the flow. On the other hand, when the difference between the intake air amount GA6 and the set value α6 is equal to or smaller than the determination value β6 (step S306; No), the process exits the flow. In this case, no deposit adheres to the EGR valve 9.

  As described above, according to the diagnostic processing of the exhaust gas recirculation device 50 according to the second embodiment, whether or not deposit is attached to the EGR valve 9, that is, the EGR valve 9 is actually fully closed at the time of the full-close command. It is possible to accurately diagnose whether or not

  In the above description, an example in which the diagnosis according to the first example and the diagnosis according to the second example are performed separately has been described, but it is also possible to perform a combination of these diagnoses. For example, after performing the diagnosis according to the second embodiment, the diagnosis according to the first embodiment can be performed. Specifically, when the difference between the intake air amount GA5 and the set value α5 is equal to or less than the determination value β5 (step S304; No), or the difference between the intake air amount GA6 and the set value α6 is equal to or less than the determination value β6. In the case (step S306; No), the processes of steps S104 and S105 or the processes of steps S204 to S206 are performed. As a result, the relationship between the command opening and the actual opening can be diagnosed only for the EGR valve 9 in which no deposit is attached to the EGR valve 9.

  Further, when it is diagnosed that deposits are attached to the EGR valve 9 by the diagnostic processing of the exhaust gas recirculation device 50 according to the second embodiment, the ECU 10 estimates the opening degree of the EGR valve 9 at the time of the fully closed command. Based on this, the operation line of the hybrid control in the vehicle 100 can be changed.

  Furthermore, in the above-described diagnosis processing of the exhaust gas recirculation device 50, an example in which the EGR valve 9 is diagnosed while the vehicle 100 is running on EV (see step S301) is shown, but EGR is also performed when the vehicle 100 is stopped. Diagnosis of the valve 9 can be performed.

(Modification)
The present invention is not limited to diagnosing the exhaust gas recirculation device 50 based on the intake air amount. In another example, the diagnosis can be performed based on the intake pipe pressure instead of the intake air amount. In this case, a pressure sensor or the like is provided on the intake passage 3, and the ECU 10 can perform the diagnosis as described above for the exhaust gas recirculation device 50 based on the intake pipe pressure detected by the pressure sensor.

  Further, the present invention is not limited to performing diagnosis of the exhaust gas recirculation device 50 by setting the engine speed to one fixed speed when performing motoring. In another example, diagnosis can be performed by setting the engine speed to a plurality of engine speeds by motoring. For example, an appropriate rotation speed is selected from a plurality of rotation speeds according to the EV traveling state and the like, and motoring is performed so that the engine speed is set to the selected rotation speed.

  In yet another example, the control of the engine speed by motoring can be feedback-controlled based on the detected engine speed. Thereby, the accuracy of diagnosis for the exhaust gas recirculation device 50 can be further improved.

1 is a schematic diagram illustrating an overall configuration of a vehicle to which a diagnostic device for an exhaust gas recirculation device according to an embodiment of the present invention is applied. It is a flowchart which shows the diagnostic process of the exhaust-gas recirculation apparatus which concerns on 1st Example. It is a flowchart which shows the diagnostic process of the exhaust-gas recirculation apparatus which concerns on the other example of 1st Example. It is a flowchart which shows the diagnostic process of the exhaust-gas recirculation apparatus which concerns on 2nd Example.

Explanation of symbols

3 Intake passage 4 Air flow meter 5 Throttle valve 6 Engine 7 Exhaust passage 8 EGR passage 9 EGR valve 10 ECU
21 Motor generator

Claims (5)

A diagnostic device for an exhaust gas recirculation device that diagnoses an exhaust gas recirculation device mounted on a hybrid vehicle having an internal combustion engine and a motor generator as a power source,
Control means for operating the internal combustion engine by driving the motor generator when the internal combustion engine is stopped ;
A diagnostic means for diagnosing the opening degree of the EGR valve of the exhaust gas recirculation device when the internal combustion engine is operated by the control means; apparatus.   The diagnostic device for an exhaust gas recirculation device according to claim 1, wherein the control means drives the motor generator so that the rotational speed of the internal combustion engine becomes a predetermined rotational speed. 3. The exhaust according to claim 1 , wherein the internal combustion engine is stopped when at least one of a case where the motor generator is used as a power source and a case where the vehicle is stopped. Diagnostic device for gas recirculation device.   The diagnostic means is based on a change in at least one of the intake air amount and the intake pipe pressure when the opening degree of the EGR valve is changed with the throttle valve set to a predetermined opening degree. The diagnosis device for an exhaust gas recirculation device according to any one of claims 1 to 3, wherein a diagnosis is made of a relationship between an opening degree commanded to the engine and an actual opening degree of the EGR valve.   The diagnostic means makes a determination with the throttle valve opening set to a predetermined opening, and changes the throttle valve opening from the predetermined opening to the fully closed state according to the determination result. Then, a diagnosis is made as to whether or not the EGR valve is set to be fully closed when a fully closed command is issued to the EGR valve. Diagnostic equipment for exhaust gas recirculation equipment.

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